Packing method and contents

Abstract

The present invention addresses the problem of providing a packing method by which both suppression of an increase in temperature of blackish foam and stacking stability can be simultaneously achieved at low cost. The problem is solved by a packing method for a packed object (100), which includes: an installation step for installing a covering plate (2) onto blackish foam (1), which is stacked in one or more layers on a pallet (4), so as to cover the uppermost main surface thereof; and a covering step for covering the outer periphery of side surfaces of the blackish foam (1) with a blackish stretch film (3).

Description

Technical Field

[0006] , , , , ,

[0001] The present invention relates to a method for packaging a foam molded body and a package.

Background Art

[0002] Bead foam molded bodies (foams) are excellent in cushioning properties and light weight, and can be designed in various shapes according to the intended use. Therefore, they are used in a wide range of applications such as packaging materials, building materials, and vehicle members. For example, bead foam molded bodies are produced by pre-foaming thermoplastic resin particles into pre-foamed particles in a molding processing factory and then molding the pre-foamed particles in a mold. Since they can be foam-molded into various shapes depending on the mold used in the in-mold molding, bead foam molded bodies are widely used in various shapes such as block shapes and box shapes.

[0003] Bead foam molded bodies containing carbon (carbon-containing bead foam molded bodies) have excellent heat insulation performance compared to general bead foam molded bodies, and in recent years, the demand for them as heat insulation materials for housing has been increasing.

[0004] As a packaging film used in a conventional method for packaging bead foam molded bodies, for example, Patent Document 1 discloses a packaging film in which small through holes are formed in a thermoplastic resin film containing a white pigment or a metal powder. Further, Patent Document 2 discloses a method of packaging a black-colored bead foam molded body with white paper.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] [[ID=4…]] The method described in Patent Document 1 is for foams coated with a low-melting-point resin and is a packaging method based on the premise of packaging bead foam molded products (foams) that do not contain carbon, i.e., are not black. For this reason, the method described in Patent Document 1 has a problem in suppressing the temperature rise of the foam in the package when packaging black foams, which absorb heat more easily than white foams. In addition, the packaging method described in Patent Document 2 has a problem in terms of the loading stability of the packaged products.

[0007] In view of the above circumstances, an object of one aspect of the present invention is to provide a foam packaging method that can suppress the temperature rise of the black foam and ensure loading stability when packaging a black foam. [Means for solving the problem]

[0008] In other words, one aspect of the present invention includes the following configuration.

[0009] A packaging method for packaging rectangular black foam made of thermoplastic resin having a brightness index L* of less than 65 into a single package, comprising: an installation step of installing a covering plate larger than the dimensions of the black foam so as to cover the main surface of at least the uppermost layer of the black foam, with respect to the black foam stacked in at least one layer on a pallet; and a covering step of covering the outer periphery of the sides of the covering plate and the black foam with a black stretch film, leaving a gap between the covering plate and the black foam.

[0010] A package comprising: a rectangular black foam made of thermoplastic resin having a lightness index L* of less than 65, laminated in at least one layer on a pallet; a covering plate, which is installed over the black foam so as to cover at least the main surface of the uppermost layer of the black foam and is larger than the dimensions of the black foam; and a black stretch film that covers the outer periphery of the covering plate and the sides of the black foam, with a gap between the covering plate and the black foam. [Effects of the Invention]

[0011] According to one aspect of the present invention, when packaging a black foam, it is possible to achieve both suppression of temperature rise in the foam and load stability. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view showing the schematic configuration of a package according to one embodiment of the present invention. [Figure 2] This is a side view showing a schematic configuration of a package according to another embodiment of the present invention. [Figure 3] Figure 2 is a side view showing a schematic configuration of a modified example of the packaging shown. [Modes for carrying out the invention]

[0013] One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents mentioned herein are incorporated as references herein. Furthermore, unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)." Furthermore, each drawing is shown for clarity when referred to in conjunction with the following description and is not necessarily drawn to a fixed scale.

[0014] [1. Technical concept of the present invention] Black foams, particularly bead foam molded products containing carbon that can act as a radiant heat transfer inhibitor, have excellent thermal insulation properties and have recently become widely used in applications such as residential insulation materials.

[0015] When using black foam materials outdoors, such as at construction sites, they are transported to the site in their packaging and, in some cases, stored outdoors in their packaging until use. However, because black foam materials easily absorb heat, their surface temperature tends to rise. Polyolefin bags were commonly used as simple packaging to protect against rain or dirt. However, with such simple packaging, the transparent bags allow sunlight to pass through, which can cause the temperature inside the packaging to rise abnormally. Therefore, it was found that when black foam materials are packaged in polyolefin bags, the foam absorbs heat and melts, causing deformation of the foam material.

[0016] One method of packaging foam that can avoid deformation of the foam due to sunlight is to package the foam with a light-shielding thermoplastic resin film, as described in Patent Document 1. However, conventional packaging methods are intended for white foam, which absorbs less heat than black foam, and when packaging black foam, the suppression of temperature rise is insufficient. Furthermore, even when packaging with a light-shielding thermoplastic resin film, the temperature of the thermoplastic resin film itself may rise, causing the surface of the foam in contact with the thermoplastic resin film to melt and deform.

[0017] Patent document 2 describes a method of packaging black foam with white paper. However, since paper packaging lacks elasticity, there was room for improvement in the loading stability of the foam, such as the tendency for the load to collapse.

[0018] Another proposed method involves covering the packaged foam (packaging) with a blue tarp or similar material to block sunlight. However, this method is difficult to implement thoroughly at construction sites. Furthermore, large-scale packaging using blue tarps or similar materials incurs high costs and presents significant disposal challenges.

[0019] The black-colored foam is a product that is prone to cracking and is traded at a relatively low cost. Therefore, it is desirable to keep the packaging method of the black-colored foam simple and low-cost, and also desirable to have good stacking stability in order to avoid damage during transportation etc.

[0020] In view of the above circumstances, when packaging the black-colored foam, an object is to provide a packaging method for the black-colored foam that can achieve both suppression of temperature rise of the black-colored foam and stacking stability at a low cost. As a result of intensive studies by the present inventors, the present invention has been completed.

[0021] [2. Packaging method for black-colored foam] A packaging method for a black-colored foam according to an embodiment of the present invention is a packaging method for packaging a rectangular black-colored foam made of a thermoplastic resin having a lightness index L* of less than 65 into one package, and at least for the black-colored foam stacked in at least one layer on a pallet, an installation step of installing a covering plate larger than the dimensions of the black-colored foam so as to cover at least the main surface of the uppermost black-colored foam, and a covering step of covering the outer periphery of the side surfaces of the covering plate and the black-colored foam with a black stretch film with a gap provided between them. Hereinafter, the "packaging method for a black-colored foam according to an embodiment of the present invention" may be referred to as the "present packaging method".

[0022] According to the above configuration, in the covering step, the outer periphery of the side surfaces of the covering plate and the black-colored foam is covered with a black stretch film with a gap provided between them and the black-colored foam. Therefore, since air intervenes between the black-colored foam and the black stretch film, the heat absorbed by the black film is less likely to be transmitted to the black-colored foam. Therefore, according to the above configuration, the temperature rise of the black-colored foam can be suppressed. Furthermore, warping, deformation, or dimensional change of the black-colored foam accompanying this temperature rise can be prevented.

[0023] Furthermore, according to the above configuration, both the covering plate that covers the main surface of the uppermost black foam and the outer periphery of the side surface of the black foam are covered with a black stretch film. Therefore, the black stretch film maintains contact between the black foam and the covering plate, preventing the black foam from collapsing and resulting in a package with loading stability.

[0024] As described above, with the above configuration, when packaging black foam, it is possible to achieve both suppression of temperature rise in the black foam and load stability.

[0025] (Loading process) This packaging method preferably includes a loading step of stacking at least one layer of black foam on a pallet. The loading step may be performed before or after the installation step, which will be described later.

[0026] In the stacking process according to one embodiment of the present invention, the number of layers in which the black foam is stacked is not particularly limited as long as it is one or more layers, and may be two or more layers, or four or more layers. Here, the number of layers of black foam can also be said to be the number of black foams stacked.

[0027] In the loading process according to one embodiment of the present invention, the method of loading the black foam (loading method) is not particularly limited, but from the viewpoint of preventing cargo collapse, alternating row loading, brick loading, pinwheel loading, and split loading are preferred.

[0028] (Installation process) This packaging method includes an installation step of installing a covering plate larger than the dimensions of the black foam so as to cover the main surface of at least the uppermost layer of the black foam, with respect to the black foam stacked in at least one layer on a pallet. In this specification, the covering plate installed on the uppermost layer of the stacked black foam may be referred to as the upper (topmost) covering plate. Here, "main surface" means the surface of the black foam that is mainly affected by the covering plate. More specifically, "main surface" means the top or bottom surface of the black foam when the stacking direction of the black foam is considered as the vertical direction.

[0029] In one embodiment of the present invention, the installation step may further include the step of placing a covering plate on a pallet. This configuration makes it possible to suppress contamination of the black foam during packaging. When the installation step includes the step of placing a covering plate on a pallet, it is preferable to perform the step of placing the covering plate on the pallet before the (stacking step). That is, it is preferable that the black foam be stacked on the covering plate placed on the pallet. In this specification, the covering plate placed on the pallet may be referred to as the lower (underlay) covering plate.

[0030] In one embodiment of the present invention, the installation step preferably further includes a step of interposing a covering plate between the black foam layers that were stacked in the loading step. The step of interposing a covering plate between the black foam layers may be performed before installing the upper covering plate and / or the lower covering plate, or after installing the upper covering plate and / or the lower covering plate. In this specification, at least one covering plate interposed between the black foam layers may be referred to as the middle (center) covering plate.

[0031] In this specification, the structure consisting of a covering plate and a black foam laminated on a pallet in the (loading process) and (installation process) may be referred to as a laminate.

[0032] (Coating process) This packaging method includes a covering step in which a black stretch film is used to cover the outer periphery of the sides of the covering plate and the black foam, while leaving a gap between the film and the black foam. Here, "leaving a gap between the film and the black foam" means that the black stretch film and the black foam are not in contact.

[0033] The covering step according to one embodiment of the present invention is a step in which, in the (loading step) and the (installation step), the covering plate and the black foam (lamination) stacked on the pallet are wrapped with a black stretch film so as to cover the entire side surface of the laminate, at least one turn (or more), preferably two turns or more, and more preferably three turns or more, so that the black foam is not exposed to the outside, with the black stretch film covering (contacting) the side surface and edges of the covering plate. By covering the laminate with a black stretch film at least once, the loading stability of the black foam can be improved.

[0034] In one embodiment of the present invention, it is preferable that the gap between the black foam and the black stretch film is 5 mm or more. If the gap between the black foam and the black stretch film is 5 mm or more, when the black stretch film absorbs sunlight and heats up, there is no risk of the black foam coming into contact with the heated black stretch film, and the temperature rise and melting of the black foam due to sunlight can be suppressed more strongly.

[0035] In the coating process according to one embodiment of the present invention, the laminate may be coated with a stretch film other than black in addition to the black stretch film. The stretch film other than black is not particularly limited, but for example, a white or transparent stretch film may be used.

[0036] [3. Packaging] The packaging provided by this packaging method will be described in detail below with reference to Figures 1 to 3. Figure 1 is a cross-sectional view showing the schematic configuration when a single foam is packaged using this packaging method. Figure 2 is a diagram showing the schematic configuration when multiple foams are packaged using this packaging method. Figure 3 is a side view showing the schematic configuration of a modified example of the packaging shown in Figure 2.

[0037] As shown in Figure 1, the package 100 provided by this packaging method comprises a single layer of black foam 1, covering plates 2a and 2b, black stretch film 3, and a pallet 4. The covering plates 2a and 2b are larger in dimensions than the black foam 1 and are installed above and below the black foam 1. Note that the package 100 only needs to include a covering plate 2a that covers at least the upper surface of the black foam 1.

[0038] The packaged product 100 has a structure in which the black foam 1 and the covering plates 2a and 2b, configured in this manner, are stacked on a pallet 4. The black stretch film 3 covers the outer periphery of the sides of the black foam 1 and the covering plates 2a and 2b, leaving a gap between it and the black foam 1. The black stretch film 3 is made to cover at least the outer periphery of the side of the covering plate 2a.

[0039] In the configuration shown in Figure 1, the black stretch film 3 is spaced apart from the side surface of the black foam 1, in contact with the outer periphery of the side surfaces of the covering plates 2a and 2b, and covers the entire upper surface of the covering plate 2a. This improves the stacking stability of the black foam 1 in the package 100. Considering the stacking stability of the black foam 1, it is sufficient for the black stretch film 3 to be in contact with at least the outer periphery of the side surface of the covering plate 2a and to cover at least the edge of the upper surface of the covering plate 2a. In this specification, the direction in which the pallet 4 is installed in the laminated structure is referred to as the lower layer, and the opposite direction is referred to as the upper layer.

[0040] The package 100 may have at least one layer of black foam 1. As shown in Figure 2, in another embodiment of the present invention, the package 100 provided by this packaging method has a configuration comprising two layers of black foam 1a and 1b. The package 100 shown in Figure 2 comprises black foam 1a and 1b, covering plates 2c, 2d and 2e, black stretch film 3, and a pallet 4.

[0041] Covering plate 2c covers the upper surface of the upper layer of black foam 1a. Covering plate 2d is interposed between the stacked black foams 1a and 1b. Covering plate 2e covers the lower surface of the lower layer of black foam 1b. The stack of black foams 1a, 1b and covering plates 2c, 2d, and 2e configured in this way is placed on the pallet 4. Note that the package 100 shown in Figure 2 only needs to include a covering plate 2c that covers the upper surface of the top layer of black foam 1a.

[0042] The black stretch film 3 covers the outer periphery of the sides of the black foams 1a and 1b and the covering plates 2c, 2d, and 2e, leaving a gap between the film and the black foams 1a and 1b. The black stretch film 3 is covered so as to be in contact with at least the outer periphery of the side of the covering plate 2c.

[0043] In the configuration shown in Figure 2, the black stretch film 3 is spaced apart from the sides of the black foams 1a and 1b, in contact with the outer periphery of the sides of the covering plates 2c, 2d, and 2e, and covers the entire upper surface of the covering plate 2c. This improves the loading stability of the black foams 1a and 1b in the package 100. Considering the loading stability of the black foams 1a and 1b, it is sufficient for the black stretch film 3 to be in contact with at least the outer periphery of the sides of the covering plate 2c and to cover the edges of the upper surface of the covering plate 2c.

[0044] The packaging 100 shown in Figure 3 differs from the configuration shown in Figure 2 in that it does not have a covering plate interposed between the black foams 1a and 1b. More specifically, in the packaging 100 shown in Figure 3, the covering plate 2f covers the upper surface of the upper black foam 1a. The covering plate 2g covers the lower surface of the lower black foam 1b. The black foams 1a and 1b are in direct contact with each other, and there is no covering plate interposed between the black foams 1a and 1b.

[0045] The packaging 100 according to one embodiment of the present invention can also be described as a packaging comprising: a rectangular black foam 1 made of a thermoplastic resin having a brightness index L* of less than 65, laminated in at least one layer on a pallet 4; a covering plate 2, which is installed over the black foam 1 so as to cover at least the main surface of the uppermost layer of the black foam 1 and is larger than the dimensions of the black foam 1; and a black stretch film 3 that covers the outer periphery of the sides of the covering plate 2 and the black foam 1, with a gap between them.

[0046] The following describes in detail the materials that make up the packaging 100 according to one embodiment of the present invention.

[0047] (Black foam 1) The black foam 1 according to one embodiment of the present invention is a black resin foam molded article having a lightness index L* of less than 65, and is not particularly limited as long as it is a bead foam molded article obtained by pre-foaming and molding foamable thermoplastic resin particles, or a bead foam molded article obtained by foaming and molding thermoplastic resin foam particles. The black foam 1 may consist of one black resin foam molded article having a lightness index L* of less than 65, or it may be composed of two or more black resin foam molded articles having a lightness index L* of less than 65 laminated together.

[0048] The thermoplastic resin constituting the foamed thermoplastic resin particles or thermoplastic foamed particles is not particularly limited, but examples include styrene-based resins such as polystyrene (PS), styrene-acrylonitrile copolymer (AS), styrene-(meth)acrylic acid copolymer (heat-resistant PS), styrene-(meth)acrylic acid ester copolymer, styrene-butadiene copolymer (HIPS), N-phenylmaleimide-styrene-maleic anhydride three-dimensional copolymer, and alloys thereof with AS (IP); vinyl-based resins such as polymethyl methacrylate, polyacrylonitrile-based resin, and polyvinyl chloride-based resin; and polyolefin-based resins such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-butene three-dimensional copolymer, and cycloolefin-based (co)polymers. Examples include polyolefin resins with rheological control by introducing branched or crosslinked structures; polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, and MXD nylon; aromatic polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; aliphatic polyester resins such as polylactic acid; and engineering plastics such as polycarbonate resin, polyphenylene ether resin (PPE), modified polyphenylene ether resin (modified PPE), polyoxymethylene resin, polyphenylene sulfide resin, polyphenylene sulfide resin, aromatic polyether resin, and polyether ether ketone resin. These may be used individually or mixed in combination of two or more. Among these thermoplastic resins, polystyrene resins are preferred because they are relatively inexpensive, can be molded using low-pressure steam without special methods, and provide high cushioning and heat insulation effects. In other words, in one embodiment of the present invention, the black foam 1 is preferably a foam made of polystyrene foam resin.

[0049] In one embodiment of the present invention, the method for making the lightness index L* of the black foam 1 less than 65, that is, the method for making the bead foam molded body made of thermoplastic resin a black color, is not particularly limited, and examples include a method of incorporating carbon into the foamable thermoplastic resin particles or thermoplastic foam particles constituting the bead foam molded body, or a method of incorporating a black pigment. Among these, the method of incorporating carbon into the foamable thermoplastic resin particles or thermoplastic foam particles is preferred because it can impart excellent heat insulation properties to the black foam 1. In other words, it is preferable that the black foam 1 according to one embodiment of the present invention contains carbon.

[0050] The carbon content of the black foam 1 according to one embodiment of the present invention is not particularly limited, but from the viewpoint of improving heat insulation, it is preferably 2% by weight or more in a 100% by weight black foam 1, and 8% by weight or less is preferable to obtain good foaming moldability.

[0051] Examples of carbon contained in black foam 1 include graphite, graphene, activated carbon, coke, and carbon black. Among these, graphite or carbon black is preferred, with graphite being more preferred, due to its excellent balance of cost and thermal insulation improvement effect.

[0052] In one embodiment of the present invention, the black foam 1 has a lightness index L* of less than 65, preferably less than 60, more preferably less than 55, and even more preferably less than 50. Foams with a lightness index L* of less than 65 are black or gray in color. Therefore, when the black foam 1 is packaged using conventional packaging methods, it may heat up due to absorption of sunlight, causing it to melt or deform. On the other hand, when the black foam 1 is packaged using this packaging method, the heating of the black foam 1 can be suppressed, so even black foam 1 with a lightness index L* of less than 65 can be packaged and stored stably.

[0053] In this specification, the lightness index L* refers to the value of the lightness index L* in the CIE1976 L*a*b* color space. For example, the lightness index L* value for white is 100, and the lightness index L* value for black is 0. The lightness index L* in the CIE1976 L*a*b* color space can be measured, for example, using a spectrophotometer (such as the Konica Minolta CM-2500d), with a xenon lamp as the light source and a measurement diameter of φ8 mm.

[0054] In one embodiment of the present invention, the shape of the black foam 1 is not particularly limited and can be rectangular, triangular or hexagonal, circular, or the like. The black foam 1 may also be embedded within a wooden panel such as a load-bearing wall panel. The shape of the black foam 1 can be appropriately set according to the desired application.

[0055] In one embodiment of the present invention, it is preferable that the foaming ratio of the black foam 1 is 60 times or more. If the foaming ratio of the black foam 1 is 60 times or more, the foam can be provided at a relatively low cost, which is economically advantageous.

[0056] Conventional packaging methods, such as those using plastic bands or vinyl strings, have been used to package black foam 1 with an expansion ratio of 60 times or more. In such cases, the corners of the molded body where the plastic bands or other materials come into contact with the black foam 1 can deform or crack. With this packaging method, the black foam 1 and the black stretch film 3 do not come into direct contact, thus enabling packaging of such foam without deformation or cracking.

[0057] (Covering plate 2) The covering plate 2 according to one embodiment of the present invention is not particularly limited, but it is preferably at least one selected from the group consisting of wooden boards, corrugated cardboard, plastic corrugated cardboard, and synthetic resin boards including foamed material.

[0058] The dimensions of the covering plate 2 are preferably such that at least one of the width and / or depth directions is greater than the outer dimensions of the black foam 1, and preferably both the width and depth directions are 5 mm or more greater than the outer dimensions of the black foam 1.

[0059] The thickness of the covering plate 2 is not particularly limited, but it must be thick enough to withstand the strength required for covering and fixing with the black stretch film 3. Specifically, a thickness of 1 mm or more is preferred, a thickness of 2 mm or more is more preferred, and a thickness of 3 mm or more is even more preferred. Alternatively, two or more covering plates 2 may be stacked to achieve the desired thickness.

[0060] (Black stretch film 3) A black stretch film 3 according to one embodiment of the present invention is made of a black synthetic resin.

[0061] In one embodiment of the present invention, the synthetic resin constituting the black stretch film 3 is not particularly limited, and examples include polyolefin resins, acrylic resins, polyvinyl chloride resins, etc. Among these synthetic resins, polyolefin resins are preferred because they have tensile breaking strength and tensile elongation that provide the stretchability to stably cover the packaged object, and polyethylene resins are particularly preferred.

[0062] The polyethylene resin is not particularly limited as long as it is an ethylene homopolymer or a copolymer mainly composed of ethylene and is applicable as a stretch film. In particular, it is preferable to use a polyethylene resin whose melt flow rate (MFR), measured at a temperature of 190°C and a load of 21.18N, is 0.5 g / 10 min or more and 7 g / 10 min or less. The lower limit of the MFR of the polyethylene resin is more preferably 0.7 g / 10 min or more, and particularly preferably 1.0 g / 10 min or more. The upper limit of the MFR of the polyethylene resin is more preferably 5.0 g / 10 min or less, and particularly preferably 3.0 g / 10 min or less. If the MFR of the polyethylene resin is 0.5 g / 10 min or more, there is no risk of excessive load on the extruder during extrusion molding, and there is no risk of problems with the dispersibility of carbon black in the resin, as described later. Furthermore, if the MFR is 7g / 10min or less, there is no risk of problems occurring with the film formation stability during inflation film molding, and there is no risk of the molded film having excessively low strength.

[0063] In this specification, "black synthetic resin" refers to a synthetic resin that exhibits a dark color having a solar absorptive rate of 90% or more in the wavelength range of 380 to 720 nm. The wavelength range of 380 to 720 nm is referred to as the visible light range, which is light that humans can perceive with the naked eye. When the absorption rate of light in the visible light range is high, it exhibits a dark color such as black or gray.

[0064] In this specification, the solar absorptance in the wavelength range of 380 to 720 nm can be measured by the following methods (1) to (5): (1) Prepare a black stretch film as a test specimen, and using a self-recording spectrophotometer, set the reflectance of a white alumina substrate to 100% and measure the reflectance (spectral reflectance) at each wavelength in the wavelength range of 380 to 720 nm at 1 nm intervals; (2) Using Appendix 3 of JIS A5759, calculate the value obtained by multiplying the spectral reflectance at each wavelength measured in (1) by the corresponding weighting coefficient at each wavelength, and calculate the solar reflectance as the sum of these values ​​(spectral solar reflectance test method); (3) Using a self-recording spectrophotometer, set the transmittance without the test specimen to 100% and measure the transmittance (spectral transmittance) at each wavelength; (4) JIS Using Appendix 3 of A5759, calculate the values ​​obtained by multiplying the spectral transmittance at each wavelength measured in (3) by the weighting coefficient at each wavelength, and calculate the solar transmittance as the sum of these values; (5) Furthermore, from the obtained solar reflectance and solar transmittance values, calculate the solar absorptance using the following formula (1): (Solar absorptivity) = 100% - (Solar reflectance) - (Solar transmittance) ... (1).

[0065] In one embodiment of the present invention, the method for making the black stretch film 3 black is not particularly limited, but one method is to blend a pigment into the synthetic resin constituting the black stretch film 3. By blending a black pigment such as carbon black or aniline black as the pigment, the black stretch film 3 can be made black, that is, the solar radiation absorptivity of the black stretch film 3 in the wavelength range of 380 nm to 720 nm can be made 90% or more. As the black pigment, carbon black is particularly preferred from the viewpoint of cost and ease of handling.

[0066] The pigment (black pigment) content in the synthetic resin is influenced by the film thickness and the desired light-shielding performance, and therefore cannot be determined definitively. However, it is preferably 3.0 to 15.0 parts by weight per 100 parts by weight of synthetic resin. In particular, the lower limit is preferably 5.0 parts by weight or more, and more preferably 6.0 parts by weight or more. The upper limit is preferably 12.0 parts by weight or less, and more preferably 10.0 parts by weight or less. If the pigment content is 3.0 parts by weight or more, the total light transmittance is low and the decrease in solar absorptive rate is suppressed, so even when exposed to sunlight, excessive temperature rise of the foam can be suppressed. Furthermore, if the pigment content is 15.0 parts by weight or less, it does not affect the scratch resistance and flexibility of the synthetic resin, so there is no risk of deterioration of moldability due to a decrease in strength and elongation of the black stretch film 3, and furthermore, there is no risk of increased cost or deterioration of lightness due to an increase in specific gravity.

[0067] In one embodiment of the present invention, the method for producing the pigment is not particularly limited, and any pigment produced by known methods such as the furnace method, channel method, or acetylene method can be used. From the viewpoint of availability, pigments produced by the oil furnace method are preferred. Furthermore, from the viewpoint of ensuring good dispersibility in the black stretch film 3, the average particle size of the pigment is preferably 10 μm or less.

[0068] A black stretch film 3 according to one embodiment of the present invention can be easily manufactured by molding a resin mixture containing the above-mentioned synthetic resin and pigment using a known molding method. To obtain a homogeneous film, it is preferable to knead the resin mixture in a heated and molten state (melt kneading) using a kneader such as a single-screw extruder, twin-screw extruder, Banbury mixer, Brabender, open roll, or kneader before molding. The molding method of the melt-kneaded mixture is not particularly limited, but examples include film formation methods such as air-cooled inflation film molding and T-die film molding. Air-cooled inflation film molding is particularly simple and economical and therefore preferred.

[0069] The thickness of the black stretch film 3 according to one embodiment of the present invention is preferably 10 μm to 250 μm, more preferably 20 μm to 150 μm, and even more preferably 25 μm to 100 μm. If the thickness of the black stretch film 3 is 10 μm or more, it can sufficiently absorb light in the visible light range, and tends to exhibit a stable dark color. If the thickness of the black stretch film 3 is 250 μm or less, good handling during packaging can be maintained, and there is no risk of unnecessarily increasing costs.

[0070] In one embodiment of the present invention, the black stretch film 3 satisfies a stretch ratio (hereinafter also referred to as elongation) of at least 250% in the longitudinal direction, and preferably satisfies a stretch ratio of 250% or more in the longitudinal direction and 150% or more in the transverse direction when stretched coaxially or sequentially biaxially. In this specification, the stretch ratio of the black stretch film 3 is a value measured by the following method in accordance with ASTM-D-882: Using a tensile and compression testing machine (manufactured by Shimadzu Corporation), the black stretch film 3, set to a width of 1 cm and a distance between chucks of 10 cm, is pulled up and down at a speed of 300 mm / min, and the elongation (%) at the time of breakage is measured and defined as the stretch ratio (%). The measurement of the stretch ratio of the black stretch film 3 is carried out in an atmosphere of 23°C and 50% RH.

[0071] Furthermore, it is preferable that the black stretch film 3 according to one embodiment of the present invention has a tensile breaking strength (hereinafter also referred to as elongation strength) of 30 MPa or more in the longitudinal direction and 15 MPa or more in the transverse direction. In this specification, the tensile breaking strength of the black stretch film 3 is a value measured by the following method in accordance with ASTM-D-882: Using a tensile and compression testing machine (manufactured by Shimadzu Corporation), the black stretch film 3, set to a width of 1 cm and a distance between chucks of 10 cm, is pulled up and down at a speed of 300 mm / min, and the strength (MPa) at which it breaks is measured and defined as the tensile breaking strength (MPa). The measurement of the tensile breaking strength of the black stretch film 3 is carried out in an atmosphere of 23°C and 50% RH.

[0072] The black stretch film 3 according to one embodiment of the present invention has the above-mentioned stretchability and tensile strength, so when wrapping the black foam 1 on the pallet 4 over the covering plate 2, it is possible to prevent the film from tearing or the workability from deteriorating.

[0073] Furthermore, it is preferable that the black stretch film 3 according to one embodiment of the present invention has ventilation holes. In this packaging method, when covering the side wall surface of the black foam 1 placed on the pallet 4 with the black stretch film 3, a gap is provided between the black foam 1 and the black stretch film 3. Here, if the black stretch film 3 has ventilation holes, outside air can be circulated through the ventilation holes, thereby suppressing the temperature rise in the space forming the gap. As a result, the rise in temperature (for example, surface temperature) of the covered black foam 1 can be further suppressed.

[0074] The shape of the ventilation holes in the black stretch film 3 is not particularly limited, but a circular shape (for example, a perfect circle or an ellipse) is preferred because it can suppress the occurrence of breakage in the black stretch film 3 due to stretching.

[0075] The diameter of the ventilation holes in the black stretch film 3 is not particularly limited, but it is preferably 0.2 mm to 5.0 mm in order to prevent tearing due to stretching of the black stretch film 3 and to suppress contamination of the black foam 1 with dust, etc., by ventilation.

[0076] The opening ratio of the vents in the black stretch film 3 is not particularly limited, but is preferably 1% to 20% per unit area. If the opening ratio of the vents in the black stretch film 3 is within the above range, it is possible to achieve both the suppression of temperature rise of the covered black foam 1 and the prevention of contamination of the black foam 1 due to dust and other particles entering through the vents by ensuring adequate ventilation.

[0077] The black stretch film 3 having ventilation holes may be a film that already has ventilation holes, or a film that does not have ventilation holes may be used in which holes have been formed by a known method such as hot needle or punching. Furthermore, the pattern of the arrangement of the ventilation holes is not particularly limited and may be in a parallel arrangement or a staggered arrangement.

[0078] In this packaging method, the black foam 1 (and the covering plate 2) may be covered with a single-layer film consisting of one type of black stretch film 3, or it may be covered with a multilayer film containing one or more types of black stretch film 3 and optionally other films. For example, a multilayer film may be formed by further covering (wrapping) the outer periphery of the black stretch film 3 that covers the outer periphery of the sides of the covering plate 2 and the black foam 1 with other films, and the black foam 1 (and the covering plate 2) may be covered with this multilayer film. Note that "multilayer" in the context of a multilayer film means that the multilayer film contains two or more types of films.

[0079] In one embodiment of the present invention, when the covering plate 2 and the black foam 1 are covered with a multilayer film, the multilayer film may consist of at least one layer of black stretch film 3. That is, the multilayer film may include one or more types of black stretch film 3 and one or more types of other films, or it may be a multilayer film consisting only of two or more types of black stretch film 3 without including other films. The other films that may be included in the multilayer film are not particularly limited, and transparent films, white films, etc., can be used. These other films may be used individually or in combination of two or more types.

[0080] In one embodiment of the present invention, if the multilayer film includes other films, these other films can also be said to be films that cover the outer periphery of the sides of the covering plate 2 and the black foam 1 together with the black stretch film 3. The other films may cover the entire side of the black stretch film 3 by only one layer, or by two or more layers. It is preferable to cover the black stretch film 3 by two or more layers with the other films, as this has the advantage of reducing the cost of the black stretch film.

[0081] (Palette 4) Pallet 4 serves as the base when the black foam 1 and the covering plate 2 are stacked. In one embodiment of the present invention, pallet 4 may be made of wood or synthetic resin. Furthermore, the shape of pallet 4 is not particularly limited and may be rectangular, for example.

[0082] In one embodiment of the present invention, the size of the pallet 4 is not particularly limited, but examples include one with a width of 1,100 mm x a length of 1,100 mm x a thickness of 125 mm, or one with a width of 1,000 mm x a length of 1,200 mm x a thickness of 150 mm.

[0083] One embodiment of the present invention may have the following configuration.

[0084] [1] A packaging method for packaging rectangular black foam made of thermoplastic resin having a brightness index L* of less than 65 into a single package, comprising: an installation step of installing a covering plate larger than the dimensions of the black foam so as to cover the main surface of at least the uppermost layer of the black foam, with respect to the black foam stacked in at least one layer on a pallet; and a covering step of covering the outer periphery of the sides of the covering plate and the black foam with a black stretch film, leaving a gap between the covering plate and the black foam.

[0085] [2] The packaging method according to [1], wherein the installation step includes the step of placing a covering plate on the pallet, and the black foam is stacked on the covering plate placed on the pallet.

[0086] [3] The packaging method according to [1] or [2], wherein the black stretch film has a thickness of 10 to 250 μm and a solar absorptance of 90% or more in the visible light region of 380 to 720 nm.

[0087] [4] The packaging method according to any one of [1] to [3], wherein the black stretch film comprises 100 parts by weight of polyolefin resin and 3 to 15 parts by weight of carbon black.

[0088] [5] The packaging method according to any one of [1] to [4], wherein the black stretch film has ventilation holes.

[0089] [6] The packaging method according to [5], wherein the opening ratio of ventilation holes per unit area of ​​the black stretch film is 1% to 20%.

[0090] [7] The packaging method according to any one of [1] to [6], wherein the covering plate is composed of at least one selected from the group consisting of wooden boards, corrugated cardboard, plastic corrugated cardboard, and synthetic resin boards, and the thickness of the covering plate is 1 mm or more.

[0091] [8] The packaging method according to any one of [1] to [7], wherein the installation step includes the step of interposing the covering plate between the stacked black foams.

[0092] [9] The packaging method according to any one of [1] to [8], wherein the gap between the black stretch film and the black foam is 5 mm or more.

[0093]

[10] A package comprising: a rectangular black foam made of thermoplastic resin having a lightness index L* of less than 65, laminated in at least one layer on a pallet; a covering plate installed over the black foam so as to cover at least the main surface of the uppermost layer of the black foam, and which is larger than the dimensions of the black foam; and a black stretch film covering the outer periphery of the covering plate and the sides of the black foam, with a gap between the covering plate and the black foam. [Examples]

[0094] Examples, comparative examples, and reference examples are given below, but the present invention is not limited thereto.

[0095] 〔material〕 The materials used in the examples, comparative examples, and reference examples are shown below.

[0096] (Foam) Foam A: Black polystyrene foam molded product using the bead method (expansion ratio 80x, brightness index 48, size: width 909mm x length 1,818mm x thickness 50mm) Foam B: White bead-type polystyrene resin foam molded product (expansion ratio 80x, brightness index 91, size: width 909mm x length 1,818mm x thickness 50mm) (covering plate) Covering board A: Wooden covering board (Size: Width 1,000mm x Length 1,920mm x Thickness 10mm) Covering board B: Plastic corrugated cardboard (Size: 1,000mm wide x 1,920mm long x 14mm thick, manufactured by Gifu Plastic Industry Co., Ltd., Texcel T14-3200) (Stretch film) Black stretch film: Dia Stretch Film Color Stretch Film BA (Black) Product number: TK-30420BLACK Thickness 20μm x Width 500mm x (Length 300m) Solar radiation absorption rate: 95%, manufactured by Tsukasa Chemical Industry Co., Ltd. Transparent stretch film: Dia Stretch Film Part number: TK-30000 Thickness 20μm x Width 500mm x (Length 300m) Solar radiation absorption rate: 0%, manufactured by Tsukasa Chemical Industry Co., Ltd. (palette) Pallet: Wooden pallet (Size: Width 1,100mm x Length 2,000mm x Thickness 150mm) [Measurement method] The evaluation methods used in the examples, comparative examples, and reference examples are described below.

[0097] (Solar radiation absorption ratio) The solar absorptance of stretch film was measured by the following methods (1) to (5): (1) A black stretch film was prepared as a test specimen, and using a self-recording spectrophotometer, the reflectance (spectral reflectance) at each wavelength in the wavelength range of 380 to 720 nm was measured at 1 nm intervals on a white alumina substrate with a reflectance of 100%; (2) Using Appendix 3 of JIS A5759, the spectral reflectance at each wavelength measured in (1) was multiplied by the corresponding weighting coefficient for each wavelength to calculate the value, and the sum of these values ​​was used to calculate the solar reflectance (spectral solar reflectance test method); (3) For the test specimen from (1), using a self-recording spectrophotometer, the transmittance without the test specimen was set to 100%, and the transmittance (spectral transmittance) at each wavelength was measured; (4) JIS Using Appendix Table 3 of A5759, the spectral transmittance at each wavelength measured in (3) was multiplied by the weighting coefficient at each wavelength to calculate the solar transmittance, and the sum of these values ​​was used to calculate the solar radiation transmittance; (5) Furthermore, from the obtained solar radiation reflectance and solar radiation transmittance values, the solar radiation absorptance was calculated using the following formula (1): (Solar absorptivity) = 100% - (Solar reflectance) - (Solar transmittance) ... (1).

[0098] (Loading stability) The condition of the packages was visually inspected while they were being transported using a forklift for 3 minutes, and the loading stability of the packages was evaluated according to the following criteria: ○: No problems such as cargo collapse will occur. ×: Problems such as cargo shifting may occur, requiring the items to be rearranged.

[0099] (Exposure test) Outdoor exposure tests were conducted as follows: Packages prepared for each example, comparative example, and reference example were left outdoors and exposed from August 10th to August 17th, 2020. During this period, the average temperature was 31.4°C, the minimum temperature was 24.7°C, and the maximum temperature was 40.5°C.

[0100] During the exposure test, the temperature of the foam in the packaging was measured at 15-minute intervals using thermocouples with the following equipment, and the highest temperature reached by the foam during the exposure period was defined as the maximum surface temperature. Thermocouple: K-type thermocouple, ESCO brand, EA742HD-32 Temperature logger: GRAPHTEC midi LOGGER GL840 (20-point type) After the exposure period, the foam was removed from the packaging and its surface properties, shape, and appearance were evaluated using the following method.

[0101] (Evaluation of surface and shape of foam after packaging) The foam was visually inspected after the exposure test, and its surface properties and shape were evaluated according to the following criteria; ○ (Good): No abnormalities were found in the beads that make up the foam. × (Defective): Enlargement and / or melting of the beads constituting the foam are observed.

[0102] (Appearance of the foam after packaging) The foam was visually inspected after the exposure test, and its appearance was evaluated according to the following criteria: ○ (Good): No dirt is visible on the surface of the foam. × (Defective): Dirt is visible on the surface of the foam.

[0103] [Example 1] Four layers of foam A were placed on top of a covering plate A (lower covering plate A) which was placed on a pallet (lower foam A), and then another covering plate A (center covering plate A) was placed on top of the lower foam A. Then, four more layers of another foam A were placed on top of the center covering plate A (upper foam A), and then another covering plate A (upper covering plate A) was placed on top of that (the stacking order from bottom to top was: polypropylene pallet / lower (underlay) covering plate A / lower foam A (4 layers) / middle (center) covering plate A / upper foam A (4 layers) / upper (topmost) covering plate A). Next, a thermocouple was attached to the approximate center (length / thickness direction) of the long side of the upper foam A. Subsequently, the sides of the laminate consisting of foam A and covering plate A were covered with black stretch film in a vertical (height) direction from the side of the pallet, so that the side walls of the laminate were wrapped three times (wrapped three times in the same place) to obtain the package. A loading stability test and an outdoor exposure test were conducted on the package, and the maximum surface temperature was measured to evaluate the loading stability, the surface properties and shape of the foam after packaging, and the appearance of the foam after packaging. The results are shown in Table 1.

[0104] [Example 2] The packaging was obtained using the same method as in Example 1, except that instead of wrapping the laminate three times with black stretch film, the side walls of the laminate were covered with black stretch film once (wrapped once in the same place), and then transparent stretch film was wrapped twice over that (wrapped twice in the same place). The physical properties of the package were then measured and evaluated. The results are shown in Table 1.

[0105] [Example 3] Except for using covering plate B instead of covering plate A as the covering plate, the packaged material was obtained using the same method as in Example 1, and its physical properties were measured and evaluated. The results are shown in Table 1.

[0106] [Example 4] Except for creating ventilation holes (hole diameter φ1 mm, staggered hole arrangement, 5% opening ratio) by perforating black stretch film with a hot needle, a packaged product was obtained using the same method as in Example 1, and its physical properties were measured and evaluated. The results are shown in Table 1.

[0107] [Comparative Example 1] Except for not using black stretch film, the packaging was prepared using the same method as in Example 1, by wrapping the side walls of the laminate three times with transparent stretch film (wrapping it three times in the same place). The physical properties were then measured and evaluated. The results are shown in Table 1.

[0108] [Comparative Example 2] Except for not using stretch film (not covering the laminate), the packaging was obtained using the same method as in Example 1, and each physical property was measured and evaluated. The results are shown in Table 1. In addition, after the exposure test, dirt caused by sand and dust was observed adhering to the surface of the foam.

[0109] [Comparative Example 3] Except for not using covering plates A (lower covering plate, middle covering plate, and upper covering plate), the packaged material was obtained using the same method as in Example 1, and its physical properties were measured and evaluated. The results are shown in Table 1.

[0110] [Reference example 1] A package was obtained using the same method as in Example 1, except that foam B was laminated instead of foam A, and the side walls of the laminate were covered with transparent stretch film three times (wrapped three times in the same place) instead of black stretch film. The physical properties of each package were measured and evaluated. The results are shown in Table 1.

[0111] [Reference example 2] A package was obtained using the same method as in Example 1, except that foam B was laminated instead of foam A. Each physical property was then measured and evaluated. The results are shown in Table 1.

[0112] [Table 1] 〔summary〕 The following is clearly evident from Table 1: (1) A comparison of Examples 1-4 and Comparative Example 1 shows that this packaging method, by packaging with black stretch film, can suppress deterioration of the surface properties and shape of the foam, such as the enlargement of the beads constituting the packaged foam and the melting of the surface of the foam, compared to packaging with conventionally used transparent stretch film.

[0113] (2) A comparison of Examples 1-4 and Comparative Example 2 shows that when the package is not wrapped in stretch film, the loading stability of the packaged goods is poor, and if left unattended, dirt adheres to the surface of the foam, resulting in a poor appearance.

[0114] (3) A comparison of Examples 1-4 and Comparative Example 3 shows that when a covering plate is not installed, the black stretch film comes into direct contact with the foam inside the package, causing the foam to heat up and the beads to enlarge, resulting in poor surface properties and shape of the foam.

[0115] (4) Based on the results of Reference Examples 1 and 2, when the foam is white (not a black foam), even if it is packaged in transparent stretch film, no problems such as deformation of the foam will occur. However, the packaging method of the present invention can also be used to package it appropriately. [Industrial applicability]

[0116] According to one embodiment of the present invention, a packaging method for black foam can be provided that achieves both suppression of temperature rise of the black foam and load stability at a low cost. The black foam can be suitably used for applications such as residential insulation. [Explanation of symbols]

[0117] 1, 1a, 1b Black foam 2a~2g Covering board 3. Black stretch film 4 pallets 100 packages

Claims

1. A packaging method for packaging a rectangular black foam made of thermoplastic resin having a lightness index L* of less than 65 into a single package, Installation step: Installing a covering plate larger than the dimensions of the black foam so as to cover the main surface of at least the uppermost layer of the black foam, with respect to the black foam stacked in at least one layer on a pallet. The process includes a covering step of covering the outer periphery of the side surface of the covering plate and the black foam with a black stretch film, while leaving a gap between the black foam and the film, The covering plate is composed of at least one selected from the group consisting of wooden boards, corrugated cardboard, plastic corrugated cardboard, and synthetic resin boards containing foamed material. The thickness of the covering plate is 10 mm or more. The aforementioned black stretch film has a thickness of 20 to 250 μm and a solar absorptance of 95% or more in the visible light region of 380 to 720 nm. A packaging method wherein, when the black stretch film has ventilation holes, the opening ratio of the ventilation holes per unit area of ​​the black stretch film is 1% to 5%.

2. The installation step includes the step of placing the covering plate on the pallet, The packaging method according to claim 1, wherein the black foam is stacked on the covering plate placed on the pallet.

3. The packaging method according to claim 1 or 2, wherein the black stretch film comprises 100 parts by weight of polyolefin resin and 3 to 15 parts by weight of carbon black.

4. The packaging method according to any one of claims 1 to 3, wherein the installation step includes the step of interposing the covering plate between the stacked black foams.

5. The packaging method according to any one of claims 1 to 4, wherein the gap between the black stretch film and the black foam is 5 mm or more.

6. A rectangular black foam made of thermoplastic resin having a lightness index L* of less than 65, with at least one layer laminated on a pallet, A covering plate is installed over the black foam, at least covering the main surface of the uppermost layer of the black foam, and is larger than the dimensions of the black foam. A black stretch film covers the outer periphery of the side surface of the covering plate and the black foam, with a gap between the black foam and the covering plate, The covering plate is composed of at least one selected from the group consisting of wooden boards, corrugated cardboard, plastic corrugated cardboard, and synthetic resin boards containing foamed material. The thickness of the covering plate is 10 mm or more. The aforementioned black stretch film has a thickness of 20 to 250 μm and a solar absorptance of 95% or more in the visible light region of 380 to 720 nm. A package in which, if the black stretch film has ventilation holes, the opening ratio of the ventilation holes per unit area of ​​the black stretch film is 1% to 5%.

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