Hollow structure plate and method for manufacturing the same

Abstract

To provide a hollow structure plate which has smoothness and is rich in designability and a method for manufacturing the same.SOLUTION: A hollow structure plate made of a thermoplastic resin includes at least a pair of plate-like bodies arranged substantially in parallel, and ribs partitioning a space between the pair of plate-like bodies. The pair of plate-like bodies and the ribs are formed with a crepe pattern, and a smooth part is provided on the surfaces of the pair of plate-like bodies. Surface roughness Ra of the pair of plate-like bodies may be 0.5 μm or less. There is also provided a method for manufacturing the hollow structure plate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hollow structure board and a manufacturing method thereof, and more particularly to a hollow structure board having smoothness and rich designability, and a manufacturing method thereof. [Background technology]

[0002] Plastic cardboard molded using resin has excellent impact resistance and compression resistance, as well as water resistance, light transparency, and recyclability, and is used for a wide range of purposes, including packing cases, returnable boxes and other containers, surface protective packaging material, partition boards, building materials, and decorative materials.

[0003] For example, Patent Document 1 discloses "a textured hollow sheet made of thermoplastic resin having two opposing liner plates and a number of ribs connecting the two liner plates, characterized in that the surface of the liner plates is provided with fine irregularities." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-99516 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in order to provide a fine unevenness on the surface of a plate-shaped body, it was necessary to bring a transfer body with a fine unevenness formed on its surface into close contact with the surface of a softened thermoplastic resin sheet, transfer the fine unevenness of the transfer body to the surface of the thermoplastic resin, and then cool and solidify the thermoplastic resin. Therefore, the work of preparing and setting up the transfer body is essential, and during that time, the machine is stopped, and work such as starting up the machine again is also required, which causes a problem of a significant decrease in manufacturing efficiency. In addition, the number of fixtures increases, making the work complicated.

[0006] In addition, although the thermoplastic resin with the fine unevenness transferred thereto is useful in that scratches, creases, etc. of the hollow structure plate are less noticeable, for example, when printing is to be performed on the surface of the hollow structure plate, there is a concern that the printability may be deteriorated. Therefore, the technical field of hollow structure plates having fine uneven patterns, etc. is still in the process of development, and new technologies are desired.

[0007] Therefore, the main object of the present invention is to provide a hollow structure board that is smooth and has a wide range of design features, and a method for manufacturing the same. [Means for solving the problem]

[0008] As a result of intensive experimental investigations, the inventors of the present application discovered a hollow structure board that is smooth and highly aesthetically pleasing, and a manufacturing method thereof, which led to the completion of the present invention.

[0009] In other words, the present invention provides a hollow structure plate made of thermoplastic resin comprising at least a pair of plate-like bodies arranged approximately parallel to each other and a rib dividing the space between the pair of plate-like bodies, wherein a matte pattern is formed on the pair of plate-like bodies and the rib, and the surfaces of the pair of plate-like bodies have smooth portions. The smooth portion may have a surface roughness of Ra 0.5 μm or less.

[0010] The present invention also provides a method for producing a hollow structure plate made of a thermoplastic resin, comprising at least a pair of plate-like bodies arranged approximately in parallel and a rib dividing the space between the pair of plate-like bodies, the pair of plate-like bodies and the rib having a matte pattern formed thereon, and the pair of plate-like bodies having a smooth surface, the method comprising at least an extrusion step of heating and kneading a thermoplastic resin having a melt flow rate (MFR) of 0.5 g / 10 min to 2.0 g / 10 min as specified in JIS K7210:2014 (ISO1133:2011) and extruding the resin at a heating and kneading temperature and a die temperature set based on the presence or absence of a melt fracture phenomenon, and a cooling step of cooling the extrusion step using a cooling sizing former, the cooling step using the cooling sizing former to cool the uncooled hollow structure plate while it is in pressurized contact with the cooling plate by vacuum suction from pores on the contact surface side of the hollow structure plate before cooling. The vacuum suction pressure may be 5 kPa or more and 20 kPa or less. In the cooling step, air may be applied under internal pressure from the center of the core metal of the die. In the extrusion step, the following temperature setting (A) or (B) may be performed. (A) Set the die temperature and the heating and kneading temperature to a temperature equal to or higher than the melting start temperature and equal to or lower than the melting start temperature + 50°C. (B) The die temperature is set to a temperature lower than the heating and kneading temperature. In the extrusion step, the die temperature may be set to a temperature that is 5° C. to 45° C. lower than the temperature set in the heat kneading. Effect of the Invention

[0011] According to the present invention, it is possible to provide a hollow structure board having smoothness and rich designability, and a manufacturing method thereof. It should be noted that the effects described here are not necessarily limited to those described herein and may be any of the effects described herein. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1A is a perspective view showing one example of an embodiment of a hollow structure plate 1 according to the present invention, and FIG. [Diagram 2] FIG. 1 is a conceptual diagram showing a schematic diagram of an example of an embodiment of a method for producing a hollow structure plate 1 according to the present invention. [Diagram 3] A is a photograph in lieu of a drawing of the hollow structure board 1 produced in Example 1, B is a partially enlarged photograph of the appearance of the outer layer of Example 1, C is a partially enlarged photograph of the appearance of the rib surface of Example 1, and D is a partially enlarged photograph of the appearance of the inner layer of Example 1. [Figure 4] A is a photograph in lieu of a drawing of the hollow structural board produced in Comparative Example 1, B is a partially enlarged photograph of the appearance of the outer layer of Comparative Example 1, C is a partially enlarged photograph of the appearance of the rib surface of Comparative Example 1, and D is a partially enlarged photograph of the appearance of the inner layer of Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1.Hollow structural board 1 Fig. 1A is a perspective view showing one example of an embodiment of a hollow structure plate 1 according to the present invention, and Fig. 1B is an enlarged view of the dashed line portion of A. The hollow structure plate 1 according to the present invention comprises at least a pair of plate-like bodies 11 arranged approximately in parallel and a rib 12 that divides the space between the pair of plate-like bodies 11, is made of a thermoplastic resin, and is characterized in that the pair of plate-like bodies 11 and the rib 12 are formed with a matte pattern, and the pair of plate-like bodies 11 have a smooth portion 13 on their surfaces.

[0014] That is, in the present invention, while the matte pattern is formed on the plate-like body 11 and the rib 12, the surface of the plate-like body 11 has a smooth portion 13 (see Figs. 1 and 3), and compared with the hollow structure plate of Comparative Example 1 shown in Fig. 4, it has a different appearance, and is smooth and rich in design. Therefore, when printing is to be performed on the surface of the hollow structure plate 1, defects such as missing dots during printing are unlikely to occur, and printability is also good. In addition, even if scratches, creases, etc. are formed, they are less noticeable compared to when there is no matte pattern, and therefore it has excellent design. Therefore, the hollow structure plate 1 according to the present invention is useful in a wide range of applications such as containers such as packing cases and returnable boxes, surface protective packaging materials, partition boards, building materials, and decorative materials.

[0015] In the present invention, the plate-like body 11 and the ribs 12 constituting the hollow structure plate 1 may be integrally molded as shown in FIG. 1, or, although not shown, may be formed separately to have a matte pattern, and then the surface of the plate-like body 11 may be smoothed and they may be adhered together using an adhesive or the like, and if necessary, further compressed to form the hollow structure plate 1.

[0016] In this specification, the "matte pattern" refers to a ripple-like pattern consisting of minute projections and recesses formed in the extending direction of the rib, as shown in Fig. 1 and Fig. 3A.

[0017] In this specification, the term "plate-like" means that the material is substantially plate-like, and may be partially curved or may have an uneven shape on part of its surface.

[0018] Furthermore, in this specification, the "rib" may be any structure that divides the space between the plate-like bodies 11 into two or more, and its shape is not particularly limited. In addition, in Fig. 1, the angle between the plate-like bodies 11 and the rib 12 is approximately 90°, but the present invention is not limited to this. The upper and / or lower ends of the ribs 12 may be subjected to processing such as rounding.

[0019] In addition, in this specification, the "smooth portion" refers to a portion without fine irregularities, and may be formed on a part or the entire surface (preferably the entire surface) of the plate-like body 11. Furthermore, as described above, the smooth portion 13 may be formed on at least a part or the entire surface of the plate-like body 11, but if necessary, the smooth portion 13 may also be formed on one or both (preferably both) of the outermost ribs 12. When the smooth portion 13 is formed on both of the outermost ribs 12, the matte pattern can be applied only within the four faces surrounded by the plate-like body 11 and the ribs 12, and an opaque hollow structure plate 1 can be formed without impairing the smoothness of the four surfaces.

[0020] In the present invention, although not shown, both ends of the hollow structure plate 1 can be processed into a desired shape by heat treatment including thermocompression bonding, or can be sealed (sealed).

[0021] In the present invention, the pair of plate-like bodies 11 and the rib 12 are made of a thermoplastic resin. Examples of the thermoplastic resin include polyester-based resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PENp), and liquid crystal polyester (LCP); polyolefin-based resins such as polyimide-based resins, polypropylene (PP), polyethylene (PE), and polyisobutylene (PIB); styrene-based resins such as polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-acrylic-styrene resin (AAS), and acrylonitrile-ethylene propylene rubber-styrene (AES); polyphenylene ether-based resins; polyamide-based resins; polycarbonate-based resins; polyarylate-based resins; polyphenylsulfone-based resins; polysulfone-based resins; and polyethersulfone-based resins. In the present invention, two or more of these may be used in combination, or commercially available products may be used.

[0022] Other examples include olefin-based elastomers, styrene-based elastomers, etc. Examples of olefin-based elastomers include ethylene-α-olefin copolymer elastomers such as ethylene-propylene copolymer elastomers (EPR), ethylene-butene copolymer elastomers (EBR), ethylene-hexene copolymer elastomers (EHR), and ethylene-octene copolymer elastomers (EOR); and ethylene-α-olefin-diene terpolymer elastomers such as ethylene-propylene-ethylidenenorbornene copolymer, ethylene-propylene-butadiene copolymer, and ethylene-propylene-isoprene copolymer. Examples of styrene-based elastomers include styrene-butadiene-styrene triblock copolymer elastomer (SBS), styrene-isoprene-styrene triblock copolymer elastomer (SIS), styrene-ethylene-butylene copolymer elastomer (SEB), styrene-ethylene-propylene copolymer elastomer (SEP), styrene-ethylene-butylene-styrene copolymer elastomer (SEBS), styrene-ethylene-butylene-ethylene copolymer elastomer (SEBC), and hydrogenated styrene-butadiene elastomer (HSBR). Examples of the elastomer include styrene-based elastomers such as styrene-ethylene propylene-styrene copolymer elastomer (SEPS), styrene-ethylene ethylene propylene-styrene copolymer elastomer (SEEPS), styrene-butadiene butylene-styrene copolymer elastomer (SBBS), partially hydrogenated styrene-isoprene-styrene copolymer elastomer, partially hydrogenated styrene-isoprene butadiene-styrene copolymer elastomer, and hydrogenated polymer-based elastomers such as ethylene-ethylene butylene-ethylene copolymer elastomer (CEBC). In the present invention, two or more of these may be used in combination, or commercially available products may be used.

[0023] In the present invention, among these, it is preferable to use a thermoplastic resin having a melt flow rate (MFR) of 0.5 g / 10 min or more and 2.0 g / 10 min or less as specified in JIS K7210:2014 (ISO1133:2011). If the MFR is less than 0.5 g / 10 min, the fluidity of the molten resin is low, the conformability is deteriorated, and molding is difficult. Also, if the MFR is more than 2.0 g / 10 min, it is difficult to maintain the structure of the hollow structure plate 1 during molding.

[0024] Examples of thermoplastic resins having an MFR of 0.5 g / 10 min or more and 2.0 g / 10 min or less include polypropylene, polyethylene, polycarbonate, and polyethylene terephthalate resins. Among these, it is particularly preferable to use polypropylene in the present invention.

[0025] In addition, the hollow structure board 1 of the present invention may contain other optional components such as, for example, ultraviolet absorbers, colorants, antioxidants, crystallization promoters, lubricants, crosslinking agents, surfactants, shrinkage prevention agents, flame retardants, and deterioration prevention agents, but the present invention is not limited to these.

[0026] The surface roughness (Ra; arithmetic mean height (μm)) of the pair of plate-like bodies 11 is not particularly limited, but is preferably Ra 0.5 μm or less, and more preferably Ra 0.4 μm or less. By making the surface roughness Ra 0.5 μm or less, it is possible to improve design, printability, and cleanability (for example, preventing adhesion of dirt, dust, etc.).

[0027] Although the lower limit of the surface roughness Ra is not particularly limited, the surface roughness is preferably Ra 0.01 μm or more, and more preferably Ra 0.05 μm or more. By making the surface roughness Ra 0.01 μm or more, the unevenness of the matte pattern can be beautifully expressed.

[0028] 2. Manufacturing method of hollow structure plate 1 2 is a conceptual diagram showing an example of an embodiment of the manufacturing method of the hollow structure plate 1 according to the present invention. The manufacturing method of the hollow structure plate 1 according to the present invention is characterized in that, in the above-mentioned manufacturing method of the hollow structure plate 1, at least an extrusion step is performed in which a thermoplastic resin having a melt flow rate (MFR) of 0.5 g / 10 min or more and 2.0 g / 10 min or less as shown in JISK7210:2014 (ISO1133:2011) is heated and kneaded, and extruded at a heating and kneading temperature and a die temperature set based on the occurrence or non-occurrence of a melt fracture phenomenon, and a cooling step is performed after the extrusion step, in which the hollow structure plate 1 before cooling is cooled using a cooling sizing former by vacuum suction from a fine hole on the contact surface side of the hollow structure plate before cooling while being pressed and contacted with the cooling plate. Furthermore, in the method for producing the hollow structure board 1 according to the present invention, other steps may be carried out as necessary.

[0029] (1) Extrusion process In the extrusion process, first, the thermoplastic resin is put into an extruder equipped with a screw or the like. The extruder may be used alone, or a tandem extruder may be used. Next, the put in thermoplastic resin is heated and kneaded by the screw of the extruder under heating, while an extrusion force is applied in the direction of the tip of the screw. The kneading conditions here vary depending on the thermoplastic resin used, but the heating conditions are, for example, 200°C or more and 300°C or less, and are preferably set to at least the melting start temperature of the thermoplastic resin. In addition, although they vary depending on the type of screw (for example, screw diameter, etc.), the screw rotation speed and extrusion speed can be set appropriately.

[0030] The melt-kneaded thermoplastic resin is extruded into a low-pressure region through a die having a predetermined shape. The die temperature and the heat-kneading temperature vary depending on the type of thermoplastic resin used, but are preferably set to a temperature between the melting start temperature and the melting start temperature +50°C, and more preferably between the melting start temperature and the melting start temperature +30°C. By setting the die temperature and the heat-kneading temperature to a temperature between the melting start temperature and the melting start temperature +50°C, it becomes easier to form a matte pattern.

[0031] Specifically, the die temperature and the heat kneading temperature can be set based on the occurrence or non-occurrence of the melt fracture phenomenon. This is based on the fact that the inventors of the present application found that the matte pattern in the hollow structure plate 1 according to the present invention is caused by the occurrence of the melt fracture phenomenon. That is, in the present invention, the die temperature and the heat kneading temperature are lowered to a temperature lower than that during normal operation (=the die temperature and the heat kneading temperature are set to a temperature equal to or higher than the melting start temperature and equal to or lower than the melting start temperature + 50°C), thereby inducing the melt fracture phenomenon and forming the matte pattern.

[0032] In addition, the inventors of the present application have discovered that, in addition to the above-mentioned conditions, the melt fracture phenomenon can be induced and a matte texture can be formed by setting the die temperature to a temperature lower than the heat kneading temperature.

[0033] In the present invention, the matte pattern can be formed on the plate-like body 11 and the rib 12 without using the transfer body used in the conventional technology, so there is no need to prepare and install the transfer body, and there is no problem of a significant drop in manufacturing efficiency, making it suitable for mass production. In addition, the number of fixtures does not increase, and the work does not become complicated.

[0034] The "melt fracture phenomenon" generally occurs when the flow rate of the thermoplastic resin becomes unstable when the thermoplastic resin passes through the die lip of the extruder, causing uneven friction between the die lip and the thermoplastic resin. Therefore, it is preferable to set the die temperature lower than the heating and kneading temperature to such an extent that the melt fracture phenomenon occurs.

[0035] More specifically, although it depends on the type of thermoplastic resin used, the die temperature is preferably set at a temperature 5°C to 45°C lower than the heat-kneading temperature, and more preferably set at a temperature 10°C to 40°C lower than the heat-kneading temperature. If the die temperature is the same as the temperature during heat-kneading or the temperature difference is less than 5°C, the matte pattern is not formed. Also, if the die temperature is more than 45°C higher than the temperature during heat-kneading, the melt viscosity is low, making production difficult and the matte pattern is not formed.

[0036] (2) Cooling process The cooling process is composed of, for example, a primary cooling (air-cooling) mechanism such as cooling air and cooling rolls, and a secondary cooling mechanism of a cooling sizing former. The secondary cooling mechanism has a cooling sizing former consisting of a pair of metal cooling plates having a gap corresponding to the thickness of the hollow structure plate 1, and cools the hollow structure plate 1 before cooling while pressing it against the cooling plates by vacuum suction from fine holes on the contact surface side of the hollow structure plate before cooling. This makes it possible to smooth the part in contact with the cooling plate, and form a smooth part 13. Furthermore, by adjusting the air pressure of the air cooling in the primary cooling mechanism, it is possible to finely adjust the shading of the matte pattern in the hollow structure plate 1.

[0037] In the cooling process, the vacuum suction pressure is preferably 5 kPa or more and 20 kPa or less. By making the pressure 5 kPa or more, the hollow structure plate 1 before cooling can be reliably pressurized and bonded to the cooling plate. In addition, by making the pressure 20 kPa or less, the expansion of the space in the inner wall can be avoided, and the structure of the hollow structure plate 1 can be maintained.

[0038] In addition, in the cooling step, air may be applied under internal pressure from the center of the core of the die on the contact surface side of the hollow structure plate 1 before cooling. The timing of the vacuum suction is preferably simultaneous with the timing of cooling the hollow structure plate 1 before cooling while being in pressure contact with the cooling plate. The internal pressure during the air application is, for example, 10 kPa or more and 130 kPa or less, and preferably 20 kPa or more and 120 kPa or less.

[0039] In the cooling process, vacuum suction is performed from the small holes on the contact surface side with the hollow structure plate 1 before cooling, and air is applied under internal pressure from the center of the die core metal, thereby further pressing the plate against the cooling plate with no gaps, and heat is exchanged.The hollow structure plate 1 is cooled and solidified while maintaining its thickness, and the hollow structure plate 1 of the present invention is obtained.

[0040] If the vacuum suction is weak or the internal pressure air supply is weak, the contact with the cooling plate becomes insufficient, and the matte pattern remains on the outer surface of the plate-like body 11, impairing the smoothness of the outer surface of the plate-like body 11. On the other hand, if the vacuum suction from the pores on the contact surface side of the hollow structure plate 1 is strong, it becomes difficult to take it out. Also, if the internal pressure air supply supplied from the center of the die core metal is strong, as described above, the space of the inner wall expands, causing manufacturing problems such as the structure of the hollow structure plate 1 being unable to be maintained.

[0041] In the cooling step, if necessary, the smooth portion 13 may also be formed on one or both (preferably both) of the outermost ribs 12.

[0042] The textured pattern of the hollow structure board 1 is a pattern of repeated projections and recesses in the direction in which the hollow structure board 1 is pulled (i.e., the longitudinal direction, the extension direction of the ribs 12), and the interval (pitch) of the projections and recesses can be controlled by adjusting the pulling speed of the puller. This allows the production of hollow structure boards 1 with different textured patterns.

[0043] (3) Other processes In the manufacturing method according to the present invention, as another step, the obtained hollow structure plate 1 may be cut to a desired size by a cutting machine, if necessary. In addition, a step may be performed in which both ends of the hollow structure plate 1 are processed into a desired shape by heat treatment including thermocompression bonding, or sealed. EXAMPLES

[0044] The present invention will now be described in further detail with reference to examples. The embodiment described below is merely a representative example of the present invention, and the scope of the present invention should not be construed as being narrow.

[0045] <Example 1> According to the above-mentioned "(1) Extrusion step" of "2. Manufacturing method of hollow structure plate 1", extrusion molding was performed. As the thermoplastic resin, polypropylene (MFR measured at 230 ° C. and 2.16 kgf: 0.75 g / 10 min, manufactured by Sun Allomer Co., Ltd.) was used. In the extrusion step, the melt was extruded from the die nozzle at a die temperature 20 ° C lower than the cylinder temperature (= heating and kneading temperature), while according to "(2) Cooling step", air with an internal pressure (50 kPa) supplied from the center of the die nozzle and vacuum suction in the cooling sizing former were appropriately adjusted to cool and solidify while in contact with the cooling sizing former without gaps, thereby producing a hollow structure plate. The obtained hollow structure plate had smoothness on the entire surface of the plate-like body, and a matte pattern was formed on the inner surface of the plate-like body and the ribs in the extension direction of the ribs.

[0046] Furthermore, when the character "a" was printed with black ink on the surface of the hollow structure board produced in Example 1, there were no missing dots and good printability was demonstrated.

[0047] Note that A in Fig. 3 is a photograph of the hollow structure board 1 produced in Example 1, B in Fig. 3 is a partially enlarged photograph of the outer layer appearance of Example 1, C in Fig. 3 is a partially enlarged photograph of the appearance of the rib surface of Example 1, and D in Fig. 3 is a partially enlarged photograph of the inner layer appearance of Example 1. In addition, the left-right direction in Fig. 3A is the extension direction of the ribs.

[0048] <Example 2> A hollow structure plate was produced in the same manner as in Example 1, except that the take-up speed of the take-up machine was increased by 25 cm / min. The obtained hollow structure plate had smoothness over the entire surface of the plate-like body, and compared to Example 1, a matte pattern with longer intervals between the projections and recesses was formed in the extension direction of the ribs.

[0049] <Comparative Example 1> A hollow structure plate was produced in the same manner as in Example 1, except that the cylinder temperature (=heating and kneading temperature) and the die temperature were the same in the extrusion process as in Example 1. No matte pattern was observed in the obtained hollow structure plate.

[0050] Note that A in Fig. 4 is a photograph of the hollow structure board produced in Comparative Example 1, B in Fig. 4 is a partially enlarged photograph of the outer layer appearance of Comparative Example 1, C in Fig. 4 is a partially enlarged photograph of the appearance of the rib surface of Comparative Example 1, and D in Fig. 4 is a partially enlarged photograph of the inner layer appearance of Comparative Example 1. In addition, the left-right direction in Fig. 4A is the extension direction of the rib.

[0051] <Comparative Example 2> A hollow structure plate was produced in the same manner as in Example 1, except that in the extrusion process, melt extrusion was performed from the die nozzle at a die temperature 40°C higher than the cylinder temperature (=heat kneading temperature). In Comparative Example 2, the melt viscosity was low, making it difficult to produce, and no matte pattern was observed in the obtained hollow structure plate.

[0052] <Comparative Example 3> A hollow structure plate was produced in the same manner as in Example 1, except that in the cooling process, internal air pressure was not applied from the center of the die mouthpiece. The contact with the cooling sizing former was partial, and as a result, a hollow structure plate with unevenness and impaired smoothness was formed on the surface of the plate.

[0053] Furthermore, when the character "a" was printed with black ink on the surface of the hollow structure board produced in Comparative Example 3, missing dots were noticeable and the printability was poor.

[0054] <Comparative Example 4> A hollow structure plate was produced in the same manner as in Example 1, except that in the cooling process, vacuum suction in the cooling sizing former was not performed, as compared with Example 1. The contact with the cooling sizing former was partial, and as a result, as in Comparative Example 3, a hollow structure plate was formed with unevenness remaining on the surface of the plate-like body and with impaired smoothness.

[0055] Furthermore, when the character "a" was printed with black ink on the surface of the hollow structure board produced in Comparative Example 4, missing dots were noticeable and the printability was poor.

[0056] These results suggest that the matte pattern can be formed by setting the temperature as in (A) or (B). It was also found that the present invention can form the matte pattern on the plate-like body and the rib without using the transfer body used in the conventional technology.

[0057] Furthermore, it was suggested that a hollow structure plate with excellent smoothness can be obtained by vacuum suction from small holes on the contact surface with the hollow structure plate 1 before cooling and / or by applying internal pressure air from the center of the die core metal, thereby exchanging heat while bringing it into pressurized contact with the cooling plate without any gaps. [Industrial Applicability]

[0058] According to the present invention, it is possible to provide a hollow structure board having smoothness and rich designability, and a manufacturing method thereof. In addition, since the manufacturing efficiency is excellent, it is suitable for mass production, and it is expected to be used in a wide range of applications such as packing cases, containers such as returnable boxes, surface protection packaging materials, partition boards, building materials, and decorative materials.

[0059] Furthermore, when printing is desired on the surface of a hollow structure board, problems such as missing dots during printing are unlikely to occur, so that the smoothness of the hollow structure board according to the present invention can be utilized to meet the need for printing. [Explanation of symbols]

[0060] 1:Hollow structure plate 11: Plate-shaped body 12: Rib 13: Smooth section

Claims

1. A pair of plate-like bodies arranged approximately parallel to each other; A rib that divides a space between the pair of plate-like bodies; A hollow structure plate made of a thermoplastic resin, comprising at least A matte pattern is formed on the pair of plate-like bodies and the rib, A hollow structure plate having smooth portions on the surfaces of the pair of plate-like bodies.

2. The hollow structure plate according to claim 1 , wherein the surface roughness of the smooth portion is Ra 0.5 μm or less.

3. A method for manufacturing a hollow structure plate made of a thermoplastic resin, comprising at least a pair of plate-like bodies arranged approximately parallel to each other and a rib dividing a space between the pair of plate-like bodies, the pair of plate-like bodies and the rib being formed with a matte pattern, and the pair of plate-like bodies having a smooth portion on their surfaces, An extrusion step of heating and kneading a thermoplastic resin having a melt flow rate (MFR) of 0.5 g / 10 min or more and 2.0 g / 10 min or less as specified in JIS K7210:2014 (ISO1133:2011), and extruding the resin at a heating and kneading temperature and a die temperature set based on whether or not a melt fracture phenomenon occurs; A cooling step of cooling the extrusion process using a cooling sizing former; At a minimum, In the cooling step, the cooling sizing former is used, A method for manufacturing a hollow structure plate, comprising: cooling an uncooled hollow structure plate while being pressed into contact with a cooling plate by vacuum suction through fine holes on the contact surface side of the uncooled hollow structure plate.

4. The method for manufacturing a hollow structure plate according to claim 3 , wherein the vacuum suction pressure is 5 kPa or more and 20 kPa or less.

5. The method for producing a hollow structure plate according to claim 3, further comprising the step of applying internal air pressure from a center of a core metal of the die in the cooling step.

6. The method for producing a hollow structure plate according to claim 3, wherein the extrusion step is performed at a temperature setting of the following (A) or (B). (A) Set the die temperature and the heat kneading temperature to a temperature equal to or higher than the melting start temperature and equal to or lower than the melting start temperature + 50°C; (B) The die temperature is set to a temperature lower than the heat kneading temperature.

7. The method for producing a hollow structure plate according to claim 3, wherein in the extrusion step, the die temperature is set to a temperature that is 5°C to 45°C lower than the temperature setting in the heat kneading step.

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