JP2697877B2 - Buffer packaging method and buffer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an "energy absorbing ability due to bending deformation" of a foamed molded product having a foamed product interposed between an object to be packaged and an inner surface of a packaging box. The present invention relates to a technical field in which cushioning of an article to be packaged is carried out by utilizing the technology.

[Conventional technology]

It is a common technique to interpose a synthetic resin foam molded article between an object to be packaged and the inner surface of a packaging box, and to perform buffer packaging of the object to be packaged by utilizing its buffering ability. However, most of them utilize the "energy absorbing ability by compressive deformation" of the synthetic resin foam molded article, and this type of buffer is not suitable for buffer packaging of articles having a low allowable impact value.

Similarly, for example, Japanese Utility Model Laid-Open No. 13817/1987,
No. 3225 discloses that a low-foaming thin sheet is formed into a tray container, and the low-foaming thin sheet is adhered on the packaging sheet in a direction in which the opening of the tray container is sealed with the packaging sheet. A method has been proposed in which the package is fixedly buffered with the packaging sheet so that the spine of the low-foamed thin sheet is in contact with the package. However, since this method mainly uses "energy absorbing ability by compressing gas in a sealed state" for buffer packaging, it is not suitable for buffer packaging of articles to be packaged having a low allowable impact value.

On the other hand, a proposal for extracting a high degree of cushioning performance [low value of maximum deceleration (low G value)] by utilizing the “energy absorbing ability due to bending deformation” of a synthetic resin foam molded article is disclosed in, for example,
JP-A-61-33958, JP-A-62-146130, JP-A-62-146130
-168875 and the like. According to these descriptions, the target synthetic resin foam molded article has an elongation (JI
SK 6767) is 15% or more and the compression set at the time of compression by 25% (JIS K 6767) is 15% or less.

[Problems to be solved by the invention]

However, when this was applied to a foamed molded article obtained by in-mold foaming of pre-expanded particles of a synthetic resin, there was a problem that a buffer performance as expected was not exhibited. In other words, when trying to apply and apply the principle of “using the energy absorbing ability by bending deformation” of the above-mentioned publication to an actual package, the foamed molded article serving as a cushioning material must be of a complicated shape. Absent. Therefore, it was attempted whether or not the production cost of the cushioning material could be reduced by preparing the pre-expanded particles by the in-mold expansion molding method. However, a) The impacted projections (columns) and walls do not always bend as designed, and depending on the direction of the impact, they may be deformed in various directions (bending deformation with twisting). Deformation as a cushioning material is not constant, the maximum deceleration (G value) becomes unstable, and the cushioning performance as expected is not exhibited. B) When shock is applied as a cushioning material, foaming occurs. The problem is that the probability of occurrence of damage to the packaged object due to local deformation or local breakage of the molded body as individual variations and a local breakage is high, and the reliability as a cushioning material is poor. The measures to increase the wall thickness for this reinforcement not only make it difficult to obtain a high level of cushioning performance, but also tend to increase the dispersion, which is not appropriate as a measure for eliminating individual dispersion of the foamed molded article. Problems, c) In the case of molded products with many pillars or protrusions as cushioning material, it is difficult to achieve uniform foaming as a whole during foam molding in the mold, and the mold releasability from the mold is poor, resulting in reduced efficiency and shape There is a problem that it is unlikely that the processing cost can be reduced.

[Means for solving the problem]

For example, JP-A-61-33958, JP-A-62-146130, JP-A-62-168875, and the like, utilizing the "energy absorption capacity by bending deformation", a high degree of In order to make the principle of taking out the cushioning performance [low value maximum deceleration (low G value)] practically applicable to the in-mold foam molding, the foam molding uses pre-expanded particles of synthetic resin. It is a molded body formed by in-mold foam molding, and its main wall is
It is composed of almost constant thickness in the range of 10 to 30 mm. The molded body was cut in the thickness direction of the molded body along the vertical axis (or horizontal axis) direction of the molded body. In the cross-section, the shape drawn by tracing the inner surface of the wall of the molded body with the opening of the molded body as the bottom is where the area has at least one trapezoidal space portion of 5 cm ² or more, The molded article is a container-shaped molded article having a concave portion, and the molded article is directed toward the surface side of the article to be packaged, and when the molded article is deformed by an applied external force, the molded article is It is important that the air in the recess is arranged so that it can move freely to other places with substantially no resistance.

In this way, when the in-mold foam molded article is interposed between the object to be packaged and the inner surface of the packaging box, the "energy absorbing ability due to bending deformation" indicated by the foam molded article can be taken out stably, and the (low) The buffering method utilizing the maximum deceleration of the value (low G value) is completed.

Hereinafter, the contents of the present invention will be described in detail with reference to the drawings and the like. First
7 are representative views of an embodiment of the packaging method of the present invention, and FIGS. 1 to 5 are detailed views of the cushioning material used in the packaging method of the present invention described in claim 2 of the present invention. 6 and 7 are cross-sectional views showing the state of use (packing method). 8 to 10 are sectional views showing another embodiment of the packaging method according to the present invention, in which a cushioning material having no flange portion is used.

6 to 7 and FIGS. 8 to 10, a common packaging method according to the present invention is such that a synthetic resin foam molded article 9 is interposed between an article 7 to be packaged and the inner surface of a packaging box 8 so as to be covered. This is a cushioning packaging method using a foamed molded article as a cushioning material to reduce the influence of external force applied to the package.

In this case, the molded body 9 is an in-mold foam molded body of synthetic resin pre-expanded particles, the main wall portions of which are all formed with a substantially constant thickness. Then, in the cross section of the molded body cut in the thickness direction of the molded body along the longitudinal axis (or the horizontal axis) of the molded body, the opening of the molded body is set as the bottom side and the inner surface of the wall of the molded body is traced. The shape to be drawn is where there is at least one of the trapezoidal spaces,
It is a container-shaped molded article having a concave portion, and the concave opening is directed toward the surface side of the article to be packaged, and when the molded body is deformed by an applied external force, air in the concave section of the molded body is formed. Are arranged in a state where they can be moved to other places freely with substantially no resistance. In other words, in the case of FIGS. 6 and 7, since there is a gap between the pair of synthetic resin foams provided opposite to each other with the packaged object interposed therebetween, the air in the recessed portion flows along the surface of the packaged item. And can be moved out of the gap between the foams with substantially no resistance. In the case of FIGS. 8 to 10 as well, the air in the depression can move out of the system from the gap 11 with substantially no resistance in the same manner as described above.

 The significance of the main part of the requirement will be described below.

First, in the above requirements, the necessity of “all of the main wall portions are configured with substantially constant thickness dimensions” is required because the target molded body is an in-mold foam molded body of synthetic resin pre-expanded particles. In view of the above, the ultimate measure is to address the above-mentioned "problem of lack of reliability as a cushioning material". Supplementing this point, the in-mold foam molded article is one in which a large number of pre-expanded particles are heated and expanded in a mold, and adjacent particles are thermally fused to each other into a desired shape. Heating at this time uses an efficient heating method in which heated steam is blown from a number of small holes drilled in the mold wall, and the foamed particles in the mold are heated directly in contact with steam, Nevertheless, uneven foaming, that is, for example, expansion of the particles on the mold wall surface side proceeds first, preventing the inflow of water vapor to the core particle side in the mold, and as a result, thermal fusion of the particles on the mold wall surface side occurs. A nonuniform foaming phenomenon such as insufficient heat fusion of the particles at the core of the molded body even though the adhesion is complete is likely to occur in the in-mold foam molding.

Therefore, even if it looks like a good foam in appearance inspection and physical property confirmation such as sampling inspection, when the foam molded body receives an impact as individual local variations, it will be deformed or broken with a bottom Is high, and the tendency is high for molded articles having irregular wall thicknesses, and those for which the wall thickness is too thick and too thin. Therefore, in the molded article of the present invention, the first meaning is that "all of the main wall portions are formed with substantially constant thickness dimensions", and in addition to this, the heat fusion of particles to the core of the molded article is completely prevented. For this purpose, the thickness was limited to a value in the range of 10 to 30 mm, and the reliability as a cushioning material was successfully improved.

Next, among the above requirements, the meaning of “a container-like shaped article having a recess where there is at least one trapezoidal space” is essentially “various depending on the direction of impact. In the direction of bending (bending deformation with torsion)
Occurs, the deformation as a cushioning material is not constant, the maximum deceleration (G value) becomes unstable, and the cushioning performance as expected is not exhibited. "

FIG. 12 shows the “bending deformation” of the molded article used in the present invention.
, The solid line indicates the prototype, and the dashed line indicates the preferred manner of deformation. The fact that the “dent has a trapezoidal shape” is combined with the aforementioned “substantially constant thickness”, which prevents the molded product from deforming in a undulating manner, and achieves the expected cushioning performance (low quality) from stable bending deformation. G value).
For this purpose, a trapezoidal concave portion may be used in a cross-section taken along the vertical axis (or horizontal axis) direction of the molded body in the thickness direction of the molded body. Shape), the bending deformation is more stable and desirable.
And the meaning that the area of the trapezoid is 5 cm ² or more, together with the thickness of the wall, when the depression is too narrow,
Structural strength is added thereto, and it becomes difficult to take out a low G value.
However, if the area of the trapezoid becomes too large, bending deformation of the ceiling of the trapezoid becomes large and instability is added. Therefore, it is better to provide an appropriate partition. The maximum value between the partitions at this time is 15
The number of trapezoids may be increased based on 0 mm. The height of the trapezoid usually ranges from 35 to 120 mm. This height is selected depending on the allowable impact force of the packaged object, the falling distance in the cushioning design, and the like. In general, a high trapezoidal shape is adopted for taking out a low G value.

The synthetic resin foam molded article applicable to the present invention has an in-mold foam having a closed cell structure having an elongation (JIS K 6767) of 13% or more and a compression set (JIS K 6767) of 15% or less when compressed at 25%. Desirably, it is a molded body. In order to easily obtain such characteristic values, the material resin is, for example, ethylene polymer, ethylene-based resin represented by ethylene-vinyl acetate copolymer, etc., propylene polymer, ethylene-propylene copolymer, etc. Select a polypropylene resin and a multi-component copolymer whose components are styrene and ethylene, or styrene, ethylene and vinyl acetate, or a multi-component copolymer such as vinylidene chloride, acrylonitrile, styrene, and N-phenylmaleimide. Is desirable. In order to form a high-quality foam, it is often advantageous to cross-link such a single resin or a mixed resin at a stage before foaming.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Embodiment As shown in FIGS. 1 to 5, the best cushioning material has a flange portion 1 protruding from a peripheral portion and two bulging portions 2 formed on an upper surface. It is in the form of a series of two hats.

In particular, as clearly shown in FIG.
Is bent by bending the middle part on the base side upward and further bending the middle part on the tip side substantially horizontally. By appropriately adjusting the protrusion length and thickness of the flange portion 1 in addition to the size of the warpage of the flange portion 1,
The buffer performance according to the weight of the packaged object can be obtained.

As described above, the rear side (the concave side of the warp) of the flange portion 1 warped upward is supported by the supporting portions 4a and 4b formed between the flange portion 1 and the side wall at an appropriate interval. This support 4
a and 4b are for adjusting the bending deformability of the flange portion 1, and the cushioning performance can also be adjusted by the width and the interval of the support portions 4a and 4b.

As is clear from FIG. 1, the flange portion 1 is notched one by one on the left and right sides, and forms a handle portion 3. The handle portion 3 is particularly easy to carry after the packaged material is clamped by the cushioning material. The reason why the support portions 4b on both sides of the handle portion 3 are wider than the support portions 4a at other positions is that the flange portion 1 on both sides of the handle portion 3 This is to prevent bending deformation.

The bulging portion 2 has a truncated quadrangular pyramid shape and is provided on the left and right sides of the upper surface. Each of the bulging portions 2 absorbs an impact by bending deformation, and each of the bulging portions 2 is formed to have a large area so as not to cause irregular lodging depending on the direction of the impact. The bulging portion 2 can obtain a cushioning performance according to the weight of the packaged object by adjusting the formation area and the thickness of the bulging portion 2 in a range that does not cause irregular lodging.

As shown in FIG. 4, a partition wall 5 is formed at the center of the front surface on the inner surface side of the cushioning material.
Divided into three blocks. As shown in FIG. 5, each block is formed with five fitting grooves 6 for fitting the items to be packaged. That is, the present cushioning material can collectively package 10 items to be packaged at a time.

Next, a usage state of the cushioning material will be described with reference to FIGS. 6 and 7. FIG.

In the figure, reference numeral 7 denotes an article to be packaged. Ten articles to be packaged 7 are fitted into fitting grooves 6 (see FIG. 5), and are sandwiched between two upper and lower cushioning members. In the illustrated use state, the upper and lower main cushioning materials are in contact with each other to cover the package 7, but the upper and lower main cushioning materials may be separated to hold the package 7. Also, the packaged object 7 held by the cushioning material is usually further stored in a box 8 such as cardboard and transported.
The tip of the flange portion 1 and the upper surface of the bulging portion 2 are respectively in contact with the inner surface of the box 8 to prevent rattling in the box 8 and
It absorbs the shock applied from outside the box 8.

Although the present embodiment has been described by taking the case of collective packaging as an example, the present invention is not limited to use in collective packaging, and may be used for packaging a single packaged object 7.

The following Table 1 is a result table of other examples of the present invention, and is a summary of the evaluation of the cushioning performance as a cushioning material when the foam molded article shown in FIGS. 8 to 10 is used as a cushioning material. . No.
FIG. 11 is a sectional view showing the dimensions of the cushioning material. Eleventh
The edge indicated by F in the figure does not directly contribute to the buffering capacity, and therefore its dimensions are not included in the height T. The role of the rim portion F is to stabilize the contact surface of the cushioning material opening and to prevent deformation of the cushioning material opening by leg opening. Therefore, the edge base F can exert its effect sufficiently if it is arranged on the entire circumference on at least three sides around the cushioning material opening and the width is about 20 to 30 mm.

According to the results in Table 1, it has been confirmed that the buffer packaging method using the cushioning material of the present invention can stably take out a G value as low as at least 12, which proves the usefulness of the present invention. .

〔The invention's effect〕

The present invention has the following effects by having the above configuration.

B) Even if the direction of the impact changes, it is unlikely that lodging deformation (bending deformation with torsion) occurs, the deformation is constant as a cushioning material, and the cushioning performance as expected [low maximum deceleration (low G)
Value)] can be taken out stably.

B) When subjected to an impact as a cushioning material, the variation of each foam molded article, which locally deforms or breaks due to bottom deformation and damages the packaged object, is greatly reduced, and Reliability can be improved.

C) During in-mold foam molding, uniform foaming can be achieved as a whole, and the upper trapezoidal depression facilitates mold releasability from the mold, enhances efficiency, and reduces shape processing costs.

It is an excellent invention that has many advantages such as, etc. and plays a large role in the industrial world.

[Brief description of the drawings]

1 to 7 are views of a foam molded article (cushion material) used in an embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a front view thereof, FIG. 3 is a side view, and FIG. Is an enlarged sectional view taken along line IV-IV in FIG. 1, FIG. 5 is an enlarged sectional view taken along line VV in FIG. 1, and FIG. 6 and FIG. It is. 8 to 11 are sectional views showing a foam molded article (cushioning material) used in another embodiment of the present invention and a use state thereof, and FIG. 12 is a conceptual diagram of a deformed state of the cushioning material of the present invention. 1 is a flange portion, 2 is a bulging portion, 3 is a handle portion, 4a and 4b are support portions, 5 is a partition wall, 6 is a fitting groove, 7 is a packaged object, 8 is a packaging box, 9 is a cushioning material ( In-mold foam molded article), 10 is a hollow (trapezoidal space) portion, and 11 is a gap portion.

Claims (2)

(57) [Claims] 1. A foamed molded article, which is used as a cushioning material, in which a molded article of a synthetic resin foam is interposed between an article to be packaged and an inner surface of a packaging box to reduce the influence of an external force applied to the article to be packaged. In the cushioning packaging method described above, the foamed molded article is a molded article obtained by in-mold foaming molding of pre-expanded particles of a synthetic resin, and the main wall portions are all formed.
It is composed of almost constant thickness in the range of 10 to 30 mm. The molded body was cut in the thickness direction of the molded body along the vertical axis (or horizontal axis) direction of the molded body. In the cross-sectional view, the shape drawn by tracing the inner surface of the wall of the molded body with the opening of the molded body as the bottom side is where the area has at least one of the trapezoidal space portions of 5 cm ² or more, The molded article is a container-shaped molded article having a concave portion, and the molded article is directed toward the surface side of the article to be packaged, and when the molded article is deformed by an applied external force, the molded article is The air in the recess is arranged so that it can move freely to other places with substantially no resistance.The foam molded article is interposed as a cushioning material between the article to be packaged and the inner surface of the packaging box. A buffer packaging method that reduces the effects of external force applied to the package. The cushioning material is a cushioning material made of a synthetic resin foam provided opposite to each other with the packaged object interposed therebetween. The cushioning material used in the method according to claim 1, wherein the cushioning material has a protrusion.