Hollow structure plate and method for manufacturing the same

Abstract

To provide a hollow structure plate which 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. Surface roughness Ra of the pair of plate-like bodies may be 1.3 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 with excellent 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] Therefore, the technical field of hollow structural panels having fine uneven patterns 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 with excellent design and a manufacturing method thereof. [Means for solving the problem]

[0008] As a result of intensive experimental investigations, the inventors of the present application discovered a hollow structure board with excellent designability and a manufacturing method thereof, and thus completed the present invention.

[0009] That is, 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, in which a matte pattern is formed on the pair of plate-like bodies and the rib. The pair of plate-like bodies may have a surface roughness of Ra 1.3 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 separating 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, the method comprising 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 setting the temperature as shown in (A) or (B) below, based on the presence or absence of the melt fracture phenomenon. (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 heat kneading temperature. Effect of the Invention

[0011] According to the present invention, it is possible to provide a hollow structure board with excellent design 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 substantially parallel to each other 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.

[0014] That is, in the present invention, the matte pattern is formed over the entire surface of the plate-like body 11 and the ribs 12 (see FIG. 3), and compared to the hollow structure board of Comparative Example 1 shown in FIG. 4, it has a different appearance and is rich in design. Even if scratches, breaks, etc. occur, they are less noticeable compared to when the matte pattern is not present. Therefore, the hollow structure board 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 rib 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 adhered together using an adhesive or the like, and further compressed, if necessary, 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 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).

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] The surface roughness (Ra; arithmetic mean height (μm)) of the pair of plate-like bodies 11 is not particularly limited, but is preferably Ra1.3 μm or less, and more preferably Ra1 μm or less. By making the surface roughness Ra1.3 μm or less, it is possible to improve design, printability, and cleanability (for example, preventing adhesion of dirt, dust, etc.).

[0026] Although the lower limit of the surface roughness Ra is not particularly limited, the surface roughness is preferably Ra 0.3 μm or more, and more preferably Ra 0.5 μm or more. By making the surface roughness Ra 0.3 μm or more, the unevenness of the matte pattern can be beautifully expressed.

[0027] 2. Manufacturing method of hollow structure plate 1 2 is a conceptual diagram showing a schematic diagram of one embodiment of the method for producing a hollow structure plate 1 according to the present invention. The method for producing a hollow structure plate 1 according to the present invention is characterized in that, in the above-mentioned method for producing a hollow structure plate, 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) is heated and kneaded, and the temperature is set to one of the following (A) or (B) depending on whether or not melt fracture occurs. (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. Furthermore, in the method for producing the hollow structure board 1 according to the present invention, other steps may be carried out as necessary.

[0028] (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.

[0029] 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 the die temperature and the heat-kneading temperature 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] (2) Cooling process The cooling step 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 the hollow structure plate 1 according to the present invention is obtained by cooling and solidifying while maintaining the thickness of the hollow structure plate 1. The pear-skin pattern in the hollow structure plate 1 is a pattern of repeated concaves and convexes in the direction in which the hollow structure plate 1 is taken up, i.e., in the longitudinal direction, in the extension direction of the ribs 12, and the interval (pitch) of the concaves and convexes can be controlled by adjusting the take-up speed of the take-up machine. This makes it possible to obtain hollow structure plates 1 with different pear-skin patterns. Furthermore, the primary cooling mechanism can adjust the wind pressure of the wind cooling to finely adjust the shading of the pear-skin pattern in the hollow structure plate 1.

[0036] (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

[0037] 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.

[0038] <Example 1> According to the above-mentioned "(1) Extrusion step" of "2. Manufacturing method of hollow structure plate 1", extrusion molding was performed at 75 cm / min. 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 cooling and solidifying according to "(2) Cooling step", to produce a hollow structure plate. The obtained hollow structure plate had a matte pattern in the extension direction of the ribs.

[0039] 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.

[0040] <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 a matte pattern with longer intervals between the projections and recesses in the extension direction of the ribs compared to Example 1.

[0041] <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.

[0042] 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.

[0043] <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.

[0044] These results suggest that the melt fracture phenomenon can be induced by setting the temperature as in (A) or (B) below, resulting in the formation of a matte texture. (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. It was also found that the present invention can form a matte pattern on the plate-like body and the ribs without using a transfer material as used in the prior art. [Industrial Applicability]

[0045] According to the present invention, it is possible to provide a hollow structure board with rich design and a manufacturing method thereof. In addition, since the manufacturing efficiency is excellent, it is suitable for mass production and is expected to be used in a wide range of applications such as packing cases, containers such as returnable boxes, surface protective packaging materials, partition boards, building materials, and decorative materials. [Explanation of symbols]

[0046] 1:Hollow structure plate 11: Plate-shaped body 12: Rib

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 hollow structure plate, wherein a matte pattern is formed on the pair of plate-like bodies and the rib.

2. The hollow structure plate according to claim 1 , wherein the pair of plate-like bodies have a surface roughness Ra of 1.3 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, A method for producing a hollow structure plate, comprising 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 setting the temperature as shown in (A) or (B) below based on the occurrence or non-occurrence of the melt fracture phenomenon. (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.

4. The method for producing a hollow structure plate according to claim 3, wherein in the extrusion step (B), the die temperature is set to a temperature 5°C to 45°C lower than the heating and kneading temperature.

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