Heavy load trestle

Abstract

To realize a novel heavy load trestle.SOLUTION: A heavy load trestle (10) has a trestle body (1) with a loading member (2) for receiving heavy objects, and the loading member (2) is composed of polycarbonate resin foam with a compression load of 20KN or more when compressed by 20%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heavy object support stand. [Background technology]

[0002] BACKGROUND ART Receiving members (heavy object placing stands) for placing heavy objects have been known in the past.

[0003] For example, Patent Document 1 discloses a heavy load support stand on which a metal coil is placed as a support object. The heavy load support stand in Patent Document 1 has an inclined surface on the upper surface side against which the support object abuts, and is configured with an upper surface member that forms the upper surface side, and a base member that forms a base below the upper surface member. The upper surface member is formed from a polypropylene-based resin foam with a high expansion ratio, while the base member is formed from a polypropylene-based resin foam with a low expansion ratio. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-126771 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the above-mentioned conventional heavy load mounting stands are excellent, there is a demand for the development of new heavy load mounting stands.

[0006] An object of one aspect of the present invention is to provide a novel heavy object support stand. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention is as follows.

[0008] [1] A heavy-load support stand comprising a support body having a support member for supporting a heavy load, the support member being made of a polycarbonate-based resin foam that has a compressive load of 20KN or more when compressed by 20%.

[0009] [2] The heavy-load support stand of [1], wherein the absolute value of the difference between the 20% compressive stress at -30°C and the 20% compressive stress at 80°C divided by the 20% compressive stress at 23°C is 0.8 or less.

[0010] [3] A heavy-duty load support stand according to [1] or [2], wherein the support body is a single structure consisting of the support member, and the foaming ratio of the polycarbonate-based resin foam constituting the support member is less than 6 times.

[0011] [4] A heavy-duty loading platform according to [1] or [2], wherein the platform body has a two-layer structure comprising the mounting member and a base member that forms a base portion below the mounting member, and the base member is made of a polycarbonate-based resin foam having a smaller foaming ratio than the polycarbonate-based resin foam that constitutes the mounting member.

[0012] [5] A heavy-duty load support stand according to [4], wherein the foaming ratio of the polycarbonate-based resin foam constituting the mounting member is 4 times or more, and the foaming ratio of the polycarbonate-based resin foam constituting the base member is less than 4 times. [Effects of the Invention]

[0013] According to one aspect of the present invention, a novel heavy object mounting stand can be realized. [Brief explanation of the drawings]

[0014] [Figure 1] 1A to 1C are a perspective view, a side view, a top view, a bottom view, and a front view showing a schematic configuration of a heavy object placement platform according to a first embodiment of the present invention. [Figure 2] 10A to 10C are a perspective view, a side view, a top view, a bottom view, and a front view showing a schematic configuration of a heavy object placement platform according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to these, and various modifications are possible within the scope of the description. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments and examples are also included in the technical scope of the present invention. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more (including A and greater than A) and B or less (including B and less than B)."

[0016] In the drawings, "LD" refers to the length direction, "LDa" refers to the front side (front side) which is one side of the length direction, "LDb" refers to the back side (rear side) which is the other side of the length direction, "WD" refers to the width direction, "HD" refers to the vertical direction, "HDa" refers to the upper side which is one side of the vertical direction, and "HDb" refers to the lower side which is the other side of the vertical direction. The "length direction" here refers to one of the horizontal directions, i.e., the length direction of the pedestal body, which is an elongated member of the heavy-load carrying platform, and the "width direction" refers to the horizontal direction perpendicular to the length direction. The "vertical direction" refers to the direction perpendicular to both the "length direction" and the "width direction." In the "vertical direction," the "upper side" refers to the side of the heavy-load carrying platform that receives (contacts) the heavy load, and the "lower side" refers to the side of the heavy-load carrying platform opposite to the "upper side."

[0017] [Embodiment 1] An embodiment of the present invention will be described in detail below. FIG. 1 shows a perspective view, a side view, a top view, a bottom view, and a front view illustrating the schematic configuration of a heavy load support platform 10 according to this embodiment. The heavy load support platform 10 according to this embodiment is a support for a long heavy load. The long heavy load to be placed on the heavy load support platform 10 is preferably a long metal heavy load such as round steel, wire rod, or H-shaped steel, or a wound metal heavy load such as a metal coil. Such long heavy loads are stacked on the heavy load support platform 10, or a wound heavy load is placed on it.

[0018] As shown in FIG. 1, the heavy object mounting stand 10 includes a mount body 1 that mainly functions as a support for a heavy object. The mount body 1 is a long member extending in the LD direction. In the heavy object mounting stand 10, multiple mount bodies 1 are arranged in parallel with a gap in the WD direction. A long heavy object is then arranged so as to intersect (preferably perpendicular to) the multiple mount bodies 1 arranged in this manner in the LD direction. Therefore, in the heavy object mounting stand 10, a long heavy object is placed across multiple mount bodies 1.

[0019] In the heavy load placing cradle 10, the cradle main body 1 has a mounting member 2 for receiving a heavy load. The mounting member 2 has a long rectangular parallelepiped shape extending in the LD direction. A receiving surface 2b for receiving a heavy load is formed on the HDa side of the mounting member 2 in the HD direction. In the heavy load placing cradle 10, the cradle main body 1 is a single structure made up of the mounting member 2. Note that in the configuration shown in FIG. 1, the receiving surface 2b is flat, but this is not limited to this and it may be any surface that is capable of receiving a heavy load. Furthermore, the shape of the mounting member 2 is not limited to a rectangular parallelepiped shape and it may be any shape that is long and has a surface that is capable of receiving a heavy load as the receiving surface 2b.

[0020] Here, conventional heavy load support stands such as those described in Patent Document 1 are made from a polypropylene resin foam with a relatively low expansion ratio, and therefore have excellent handleability and sufficient load-bearing capacity. On the other hand, there is a demand for the development of a new heavy load support stand.

[0021] In the heavy load mounting cradle 10 according to this embodiment, the mounting member 2 of the cradle main body 1 is made of a polycarbonate resin foam that has a compressive load of 20 KN or more when compressed by 20% (hereinafter sometimes referred to as the 20% compressive load). Therefore, the heavy load mounting cradle 10 is a novel heavy load mounting cradle, as the material of the mounting member 2 is different from conventional ones. Furthermore, since the polycarbonate resin foam that constitutes the mounting member 2 has a compressive load of 20 KN or more when compressed by 20%, the heavy load mounting cradle 10 has sufficient load-bearing capacity for a heavy load (particularly the long metal heavy load described above) to be placed on it. The 20% compressive load of the mounting member 2 is preferably 22 KN or more, and more preferably 24 KN or more.

[0022] The mounting member 2 of the gantry body 1 will be described in further detail below.

[0023] (Placement member 2) Any foam can be used as the polycarbonate-based resin foam constituting the mounting member 2, as long as it is a foam using a polycarbonate-based resin as a base resin. Preferably, the polycarbonate-based resin foam is a polycarbonate-based resin foamed bead molded product (hereinafter referred to as a PC foamed molded product). A PC foamed molded product can be produced by in-mold molding of polycarbonate-based pre-expanded resin particles (hereinafter referred to as PC pre-expanded resin particles) obtained by pre-expanding polycarbonate-based expandable resin particles (hereinafter referred to as PC expandable resin particles).

[0024] The polycarbonate resin has a polyester structure of carbonic acid and glycol or dihydric phenol, and is particularly preferably one containing an aromatic group. Examples of polycarbonate resins containing an aromatic group include aromatic polycarbonates derived from bisphenols, such as 2,2-bis(4-oxyphenyl)propane, 2,2-bis(4-oxyphenyl)butane, 1,1-bis(4-oxyphenyl)cyclohexane, 1,1-bis(4-oxyphenyl)butane, 1,1-bis(4-oxyphenyl)isobutane, and 1,1-bis(4-oxyphenyl)ethane. These polycarbonate resins are preferred because of their excellent heat resistance.

[0025] Furthermore, within the scope of the object and effect of the present invention, the mounting member 2 may be formed from a resin foam containing a polycarbonate resin and other resins, such as polypropylene resin, acrylic resin, saturated polyester resin, acrylonitrile butadiene styrene (ABS) resin, polystyrene resin, polyphenylene oxide resin, etc.

[0026] As one embodiment of the present invention, a method for producing a PC foam molded article will be described below.

[0027] The PC expandable resin particles can be produced by known production methods, but either the following first or second production method is preferred in terms of ease and stability of production.

[0028] The first method for producing PC expandable resin particles is a method comprising the following steps (1) to (3): (1) Using an extruder, resin components including a polycarbonate resin, a blowing agent, and, if necessary, additives are melt-kneaded. (2) The molten mixture is extruded into a cutter chamber filled with pressurized circulating water through a die with many small holes attached after the extruder. (3) Immediately after extrusion, the molten mixture is cut by a rotating cutter in contact with the die and cooled and solidified by the pressurized circulating water.

[0029] The second method for producing PC expandable resin particles is as follows: resin particles containing a resin component including a polycarbonate resin and, if necessary, additives are suspended in water, and a blowing agent is supplied to the resin particles to incorporate the blowing agent into the resin particles, thereby obtaining expandable resin particles.

[0030] From the viewpoint of simplicity of equipment and ease of production, the first method for producing PC expandable resin particles is more preferred.

[0031] The blowing agent may be a volatile blowing agent and / or an inorganic blowing agent. Specific examples of volatile blowing agents include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, aliphatic alcohols, aliphatic ketones, and halogenated hydrocarbons. Aliphatic hydrocarbons include propane, n-butane, i-butane, n-pentane, i-pentane, and hexane. Alicyclic hydrocarbons include cyclobutane, cyclopentane, and cyclohexane. Aromatic hydrocarbons include benzene, toluene, and xylene. Aliphatic alcohols include methanol, ethanol, and propanol. Aliphatic ketones include acetone and methyl ethyl ketone. Halogenated hydrocarbons include 1-chloro-1,1-difluoroethane, pentafluoroethane, 1,1,1,2-tetrafluoroethane, and 1,1-difluoroethane. Inorganic blowing agents include inorganic gases such as carbon dioxide (CO2), nitrogen gas (N2), and air. In this embodiment, the above-mentioned foaming agents can be used alone or in combination of two or more. For example, different types of foaming agents, such as an inorganic foaming agent and a volatile foaming agent, can be used in combination. The amount of foaming agent used is appropriately determined depending on the type of foaming agent and the desired expansion ratio. When the amount of foaming agent used is determined depending on the desired expansion ratio, the density of the PC foam molded product is determined by the expansion ratio, so the amount of foaming agent used is determined mainly by the desired density of the PC foam molded product.

[0032] Any known method can be used to pre-expand the PC expandable resin particles. For example, the PC expandable resin particles are expanded with heated steam to a desired expansion ratio to form PC pre-expanded resin particles, which are then cured for a certain period of time as necessary. The resulting PC pre-expanded resin particles are then used for molding.

[0033] In this embodiment, the obtained PC pre-expanded resin particles are heated by steam in a conventional molding machine under normal molding conditions to produce a PC foamed molded article. Specifically, a preferred method for molding a PC foamed molded article is to fill a mold with the PC pre-expanded resin particles and further expand them by steam heating to fuse and integrate the PC pre-expanded resin particles to produce a PC foamed molded article. The reasons for this are as follows: (1) even complex shapes can be produced relatively easily, and (2) the PC foamed molded article has excellent density uniformity, making it easy to obtain relatively uniform mechanical properties. As a result, when comparing foamed molded articles of the same density, it is easier to achieve high compressive stress and high energy absorption performance than foamed molded articles of the same density obtained by methods other than in-mold molding.

[0034] In this embodiment, the PC foam molded article may contain additives such as antioxidants, weather resistance improvers, antistatic agents, colorants, flame retardant improvers, and electrical conductivity improvers, as needed.

[0035] These additives may be conventionally known additives that can be used in the production of PC foam molded products. There are no limitations on the colorants listed above as examples of additives. PC foam molded products can be natural in color without the addition of colorants. However, to impart design features or to make stains that accumulate over time less noticeable, colorants such as blue, red, and black can be added to create a desired color.

[0036] In the heavy load mounting stand 10 according to this embodiment, the expansion ratio of the PC foam molding forming the mounting member 2 is less than 6 times (density 200 kg / m 3 It is preferable that the density is less than 5 times (density 240 kg / m 3This makes it easy to realize a PC foam molded article with a compressive load of 20 KN or more when compressed by 20%. From the viewpoint of lightness, the expansion ratio of the PC foam molded article is preferably 1.5 times or more (density 800 Kg / m or more). 3 It is preferable that the density is at least twice as high (density 600 kg / m 3 The expansion ratio of the PC foam molded article is calculated by submerging the density of the PC foam molded article in water and multiplying it by the density of the polycarbonate resin (1,200 kg / m or less). 3 ) by the calculated value (expansion ratio of PC foam molded product = density of polycarbonate resin / density of PC foam molded product).

[0037] In the heavy-load loading platform 10, it is preferable that the loading member 2 has a value (hereinafter sometimes referred to as the 20% compressive stress change rate) of 0.8 or less, obtained by dividing the absolute value of the difference between the 20% compressive stress at -30°C and the 20% compressive stress at 80°C by the 20% compressive stress at 23°C.

[0038] The 20% compressive stress change rate will be specifically described. First, the compressive stress (20% compressive stress) of the PC foam molded article forming the mounting member 2 at 20% compression at −30° C. is calculated as C (-30) The compressive stress at 20% compression at 80°C is C (80) The compressive stress at 20% compression at 23°C is C (23) The above 20% compressive stress change rate is C (-30) and C (80) The absolute value of the difference between (23) This is the value obtained by dividing by , and corresponds to the left side of the following formula (1). As shown in the following formula (1), the 20% compressive stress change rate is preferably 0.8 (80%) or less. More preferably, the 20% compressive stress change rate is 0.7 (70%) or less. Furthermore, the smaller the 20% compressive stress change rate, the better, but it is preferably 0.1 or more, and more preferably 0.2 or more. |C (-30) -C (80) | / C (23) ≦0.8 … (1) When the 20% compressive stress change rate is 0.8 or less, the change in 20% compressive stress of the PC foam molded article between low and high temperatures is small, and the 20% compressive stress at room temperature is relatively high in the mounting member 2. Therefore, the mounting member 2 exhibits little change in 20% compressive stress over a wide range from low to high temperatures (for example, a range of -30°C to 80°C), maintaining a stable shape, and exhibiting relatively high load-bearing performance.

[0039] On the other hand, when the 20% compressive stress change rate exceeds 0.8, the mounting member tends to lose its superiority over conventional polypropylene resin foams in terms of the temperature dependency of compressive stress.

[0040] Also, 20% compressive stress C at -30℃ (-30) The 20% compressive stress C at 80°C is preferably 4.0 MPa to 25.0 MPa, and more preferably 4.5 MPa to 20.0 MPa. (80) The 20% compressive stress C at 23°C is preferably 2.0 MPa to 13.5 MPa, and more preferably 2.5 MPa to 10.0 MPa. (23) The 20% compressive stress C at -30°C is preferably 3.0 MPa to 20.0 MPa, and more preferably 3.3 MPa to 15.0 MPa. (-30) , 20% compressive stress C at 80℃ (80) , and 20% compressive stress C at 23°C (23) When the value of is in the above range, the effect of being able to exhibit stable load-bearing performance over a wide temperature range is achieved.

[0041] 20% compressive stress C at -30℃ (-30) , 20% compressive stress C at 80℃ (80) , and 20% compressive stress C at 23°C (23) can be measured in accordance with JIS K 7181:2011.

[0042] For example, by using the above-mentioned aromatic group-containing polycarbonate resin, which has high heat resistance, as the raw material for the PC foam molded article, the 20% compressive stress change rate can be reduced to 0.8 or less.

[0043] Furthermore, from the viewpoint of increasing the 20% compressive stress described above, the closed cell ratio of the PC foam molded article is 70% or more, preferably 80% or more, and more preferably 85% or more.

[0044] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0045] The heavy object mounting stand according to this embodiment differs from that of embodiment 1 in that the stand body has a two-layer structure including a mounting member and a base member. Fig. 2 shows a perspective view, a side view, a top view, a bottom view, and a front view showing the schematic configuration of the heavy object mounting stand 10A according to this embodiment.

[0046] As shown in Fig. 2, in the heavy object mounting cradle 10A according to this embodiment, the cradle main body 1A has a two-layer structure consisting of a mounting member 2A and a base member 3. The base member 3 has a long, approximately cubic appearance, and its external shape when viewed from the HDa side is approximately the same as that of the mounting member 2A. The base member 3 is in contact with the HDb side surface of the mounting member 2A, and forms a base portion on the HDb side of the mounting member 2A. The base member 3 is made of a polycarbonate-based resin foam with a smaller expansion ratio than the polycarbonate-based resin foam that constitutes the mounting member 2A.

[0047] As described above, according to the heavy object mounting gantry 10A of this embodiment, the gantry main body 1A is a two-layer structure having a mounting member 2A with a high foaming ratio and a base member 3 with a low foaming ratio. In this two-layer structure, the mounting member 2A is relatively lightweight while ensuring load-bearing capacity, and the base member 3 has a relatively higher load-bearing capacity than the mounting member 2A. Therefore, according to the heavy object mounting gantry 10A of this embodiment, the weight of the portion having the receiving surface 2b for receiving the heavy object (the mounting member 2A) can be reduced, while the base member 3 can be made to exhibit sufficient load-bearing capacity. In other words, according to the heavy object mounting gantry 10A of this embodiment, the gantry main body 1A can be made as light as possible while exhibiting a high load-bearing capacity sufficient to support the heavy object to be placed thereon.

[0048] Furthermore, when reducing the weight of the gantry body while maintaining its load-bearing capacity, the heavy object mounting gantry 10A of this embodiment offers greater freedom in designing the gantry body 1A compared to when the gantry body is a single structure of a mounting member.

[0049] Furthermore, according to the heavy object mounting stand 10A of this embodiment, the mounting member 2A and the base member 3 are separate components of the stand main body 1A. Therefore, even if either the mounting member 2A or the base member 3 is damaged, only the damaged member needs to be replaced, which reduces the operating cost.

[0050] Furthermore, since the mounting member 2A and the base member 3 are made of the same material, even when the heavy object mounting stand 10A is in use, the amount of broken members that are discarded can be reduced, and material recycling can be carried out.

[0051] Furthermore, in the heavy-weight object mounting stand 10A according to this embodiment, the mounting member 2A, which has a high foaming ratio and a receiving surface 2b for receiving a heavy object, is relatively easily deformed. Therefore, when a heavy object is placed on the receiving surface 2b, the receiving surface 2b of the mounting member 2A deforms to match the shape of the contact portion with the heavy object, resulting in a state of wide surface contact with the heavy object. Therefore, the loading force from the heavy object can be dispersed in the mounting member 2A, providing sufficient load-bearing capacity to support the heavy object. Furthermore, because the mounting member 2A has a high foaming ratio and is relatively easily deformed (soft), damage to the wrapping covering the heavy object can be prevented, for example.

[0052] If the mounting member 2A has a low foaming ratio and is relatively hard to deform (hard), when a long heavy object is placed on the mounting member 2A or moved from the mounting member 2A, the heavy object may move slightly while in contact with the mounting member 2A, which may damage the wrapping covering the heavy object. In contrast, the heavy object mounting stand 10A according to this embodiment has a soft mounting member 2A, which can prevent such damage to the wrapping.

[0053] In the heavy load mounting stand 10A according to this embodiment, the 20% compression load of the polycarbonate-based resin foam constituting the mounting member 2A is 20 KN or more, and preferably 22 KN or more. The expansion ratio of the polycarbonate-based resin foam constituting the mounting member 2A may be any expansion ratio that provides a 20% compression load of 20 KN or more, but is preferably 4 times or more and less than 6 times, and more preferably 5 times or more and less than 6 times.

[0054] The 20% compression load of the polycarbonate-based resin foam constituting the base member 3 is preferably 20 KN or more, more preferably 24 KN or more. The expansion ratio of the polycarbonate-based resin foam constituting the base member 3 may be lower than the expansion ratio of the polycarbonate-based resin foam constituting the mounting member 2A, but is preferably less than 4 times, more preferably less than 3 times.

[0055] Furthermore, from the viewpoint of minimizing the change in 20% compressive stress over a wide range from low to high temperatures, it is preferable that the 20% compressive stress change rate of the base member 3 is 0.8 or less, similar to the mounting member 2 A. In other words, it is preferable that the absolute value of the difference between the 20% compressive stress at −30° C. and the 20% compressive stress at 80° C. divided by the 20% compressive stress at 23° C. is 0.8 or less.

[0056] As shown in FIG. 2, in the gantry body 1A of the heavy-load mounting gantry 10A, the mounting member 2A and the base member 3 preferably engage with each other via concave and convex portions, and more preferably fit together. Specifically, the HDb-side surface of the mounting member 2A has convex portions 2c and 2d. The HDa-side surface of the base member 3 has concave portions 3c and 3d. The surface constituting the convex portion 2c has a surface that intersects at least the LD direction. The surface constituting the convex portion 2d has a surface that intersects at least the WD direction. The concave portions 3c and 3d engage with the convex portions 2c and 2d, respectively. The engagement between the convex portion 2c and the concave portion 3c prevents unintended displacement of the mounting member 2A relative to the base member 3 at least in the LD direction. The engagement between the convex portion 2d and the concave portion 3d prevents unintended displacement of the mounting member 2A relative to the base member 3 at least in the WD direction.

[0057] Therefore, the heavy object mounting stand 10A according to this embodiment can prevent the mounting member 2A from unintentionally separating from the base member 3 during use. That is, it is possible to realize a heavy object mounting stand 10A in which the stand main body 1A is less likely to be damaged.

[0058] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Example]

[0059] Examples, comparative examples and reference examples are given below, but the present invention is not limited to these.

[0060] The measurement and evaluation methods used in the following examples and comparative examples are as follows.

[0061] <Measurement method> [Bulk expansion ratio of pre-expanded particles] The bulk expansion ratio of the pre-expanded particles was calculated by placing the pre-expanded particles in a measuring cylinder so that the volume was 1,000 cc, measuring the weight, and using the following formula. Bulk expansion ratio (cc / g) = 1,000 cc / [weight of pre-expanded particles (g)] ... (2) [density] The density of the foamed molded article was calculated according to the following formula in accordance with JIS K 7222:2005. Density (Kg / m 3 ) = Weight of foamed molded product (Kg) / Volume of foamed molded product (m 3 )…(3) [Expansion ratio] The expansion ratio of the foamed molded article was calculated from the above density using the following formula. Expansion ratio (times) = 1,200 (Kg / m 3 ) / density(Kg / m 3 ) …(4) [20% compressive stress] The resulting foam molded article was cut into a size of 250 mm long, 120 mm wide, and 60 mm thick to serve as a test specimen (excluding the foam molded article skin layer). Using a thermostatically controlled tensile / compression universal material testing machine, Technograph (Minebea Co., Ltd.), the test environment temperature was set to -30°C to +80°C, and the test specimen was left in the thermostatic chamber for 3 to 5 hours to adjust the temperature of the test specimen to the test environment temperature. The load (20% compression load) at 20% compression (12 mm displacement) was then measured at a compression rate of 10 mm / min in the temperature range of -30°C to +80°C, and the compressive stress (MPa) was calculated.

[0062] The 20% compressive strength measured at temperatures of -30℃, 23℃, and 80℃ (C (-30) , C (23) , C (80) From this, the 20% compressive strength temperature change rate was calculated based on the following formula (5). 20% compressive strength temperature change rate = |C (-30) -C (80) | / C (23) …(5) <Evaluation method> The following evaluation criteria were set and evaluated.

[0063] (20% compressive load at room temperature (23°C): Evaluation index for load-bearing performance) Good: 20% compression load is 20KN or more Not allowed: 20% compression load less than 20KN (20% compressive stress temperature change rate: evaluation index for temperature dependence of compressive stress) Good: 20% compressive stress temperature change rate is less than 0.6 Acceptable: 20% compressive stress temperature change rate 0.6 to 0.8 Unacceptable: 20% compressive stress temperature change rate exceeds 0.8 (comprehensive evaluation) Pass: 20% compressive load and 20% compressive stress temperature change rate are both "pass" or higher Unacceptable: At least one of the 20% compressive load and 20% compressive stress temperature change rate is "unacceptable." Example 1 [Formation of expandable resin particles] 80 parts by weight of polycarbonate resin (manufactured by Mitsubishi Engineering Plastics Corporation; NOVAREX M7027BF), 20 parts by weight of polycarbonate resin (manufactured by Mitsubishi Engineering Plastics Corporation; LUPILON H-4000), and 0.5 parts by weight of talc (manufactured by Hayashi Kasei Co., Ltd.; Talcan Powder TP-20) were fed into a 40 mm diameter co-meshing twin-screw extruder (first extruder) at a total feed rate of 50 kg / hr. The cylinder temperature after the raw material feed section of the twin-screw extruder was set to 260°C, and the feed materials were melt-kneaded. Next, 4.0 parts by weight of ethyl chloride and 4.0 parts by weight of cyclopentane as foaming agents were injected into the cylinder after the raw material feed section of the twin-screw extruder, per 100 parts by weight of the melt obtained by melt-kneading, and further melt-kneaded.

[0064] The resulting melt (melt impregnated with the blowing agent) was then supplied to a 90 mm diameter single-screw extruder (second extruder) through a continuation pipe set at 220°C. A gear pump set at 210°C and a diverter valve were connected to the tip of the single-screw extruder. A die was connected downstream of the diverter valve. The die had 55 small holes with a diameter of 0.65 mm and a land length of 5.0 mm and was set at a temperature of 270°C. The cylinder temperature of the single-screw extruder was then set at 210°C to knead the melt, and the melt obtained by melt kneading was extruded through the die connected to the tip of the single-screw extruder at an extrusion (discharge) rate of 54 kg / hr into pressurized water at a temperature of 94°C and a water pressure of 1.3 MPa.

[0065] Immediately after that, a rotary cutter with four blades was used to cut the melt into particles by rotating the cutter at a rotation speed of 2,000 rpm, thereby forming expandable resin particles for molding in a mold.

[0066] [Formation of pre-expanded particles] The resulting expandable resin particles were placed in a pre-expanding machine and expanded by introducing steam at 0.16 MPa for 150 seconds. This resulted in the formation of pre-expanded particles. The bulk expansion ratio of the resulting pre-expanded particles was 30 times (cc / g).

[0067] [Production of foamed bead molded body (PC foamed molded body)] A sample of a PC foam molded article for compressive stress measurement was produced as follows. The obtained pre-expanded particles were filled into a mold (in-mold molding mold) attached to a foamed polypropylene molding machine, and water vapor of 0.24 MPa was introduced for 30 seconds to cause in-mold foaming. The resin foam molded article in the mold was then water-cooled until the pressure pressing the mold down to 0.015 MPa (gauge pressure), producing a sample of a PC foam molded article. The sample measured 370 mm long x 320 mm wide x 80 mm thick, with a density of 350 kg / m. 3 It is a rectangular parallelepiped foam molded body with an expansion ratio of 3.4 times and a closed cell ratio of 92%.

[0068] Test pieces for measuring compressive load and compressive stress were cut out from the prepared PC foam molded article. The cut-out test pieces were then subjected to compressive load and compressive stress tests at 23°C, as well as compressive stress tests at test temperatures of -30°C and 80°C. The compressive load (20% compressive load) at which the thickness displacement (strain) rate was 20% was determined from the test at 23°C, and the compressive stress (20% compressive stress) was calculated. Furthermore, the compressive stress (20% compressive stress) at which the thickness displacement (strain) rate was 20% was calculated from the tests at -30°C and 80°C. The results are shown in Table 1. The PC foam molded article sample of this example corresponds to the mounting member 2 of the platform main body 1 of the heavy-load mounting platform 10 according to embodiment 1.

[0069] Example 2 The sample of the PC foam molded article of Example 1 (density 350 kg / m 3 A test piece (hereinafter referred to as test piece 1) measuring 250 mm in length, 120 mm in width, and 30 mm in thickness was cut out from the foam (expansion ratio: 3.4). On the other hand, another PC foam molded sample was cut out measuring 370 mm in length, 320 mm in width, and 80 mm in thickness, with a density of 250 kg / m 3 A rectangular parallelepiped foam molded article with an expansion ratio of 4.8 and a closed cell ratio of 88% was separately produced. A test piece (hereinafter referred to as Test Piece 2) measuring 250 mm in length, 120 mm in width, and 30 mm in thickness was cut out from the other PC foam molded article sample.

[0070] On the bottom, density 350Kg / m 3 (expansion ratio 3.4 times) test piece 1 was placed on the upper side of the test piece 1, and a density of 250 kg / m 3 Test piece 2 (expansion ratio 4.8 times) was laminated with adhesive to prepare test piece 3 consisting of a two-layer structure (upper layer; test piece 2: expansion ratio 4.8 times / lower layer; test piece 1: expansion ratio 3.4 times) measuring 250 mm in length, 120 mm in width, and 60 mm in thickness.

[0071] Test piece 2 (upper layer) was subjected to compressive load and compressive stress tests in the same manner as in Example 1. Then, the 20% compressive load at 23°C was determined, and the 20% compressive stress at 23°C was calculated. In addition, the 20% compressive stress at -30°C and 80°C was calculated. The results are shown in Table 1. Note that the two-layered test piece 3 of this example corresponds to the gantry body 1A of the heavy-load support gantry 10A according to embodiment 2. In test piece 3, test piece 1 corresponds to the base member 3, and test piece 2 corresponds to the support member 2A.

[0072] (Comparative Example 1) Density 265kg / m 3 Except for using a foam molded article made of a polypropylene resin with an expansion ratio of 3.4 and a closed cell content of 93%, compressive load and compressive stress tests were carried out in the same manner as in Example 1. Then, the 20% compressive load at 23°C was determined and the 20% compressive stress at 23°C was calculated. In addition, the 20% compressive stresses at -30°C and 80°C were calculated. The results are shown in Table 1.

[0073] (Comparative Example 2) Density 111kg / m 3 Compressive load and compressive stress tests were carried out in the same manner as in Example 1, except that a foamed molded article made of a polycarbonate resin with an expansion ratio of 10.8 and a closed cell content of 82% was used. The 20% compressive load at 23°C was then determined and the 20% compressive stress at 23°C was calculated. The 20% compressive stresses at -30°C and 80°C were also calculated. The results are shown in Table 1.

[0074] [Table 1] [Industrial Applicability]

[0075] The present invention can be used in a heavy object support stand on which a long heavy object is placed. [Explanation of symbols]

[0076] 1. 1A Stand body 2, 2A Mounting member 2b receiving surface 2c, 2d convex part 3 Foundation members 3c, 3d recess 10, 10A Heavy Load Stand

Claims

1. a base body having a mounting member for supporting a heavy object; The heavy load mounting stand is made of a polycarbonate resin foam that has a compressive load of 20 KN or more when compressed by 20%.

2. The heavy-duty loading platform according to claim 1, wherein the absolute value of the difference between the 20% compressive stress at -30°C and the 20% compressive stress at 80°C divided by the 20% compressive stress at 23°C is 0.8 or less.

3. the gantry body is a single structure made up of the mounting member, 3. The heavy load support platform according to claim 1, wherein the foaming ratio of the polycarbonate resin foam constituting the support member is less than 6 times.

4. The gantry body includes: The mounting member; a base member that forms a base portion below the mounting member; 3. The heavy-duty mounting platform according to claim 1, wherein the base member is made of a polycarbonate-based resin foam having a foaming ratio smaller than that of the polycarbonate-based resin foam constituting the mounting member.

5. the expansion ratio of the polycarbonate-based resin foam constituting the mounting member is 4 times or more; 5. The heavy load support platform according to claim 4, wherein the foaming ratio of the polycarbonate-based resin foam constituting the base member is less than four times.

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