WO2024048521A1 - 発泡樹脂シート - Google Patents

発泡樹脂シート Download PDF

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Publication number
WO2024048521A1
WO2024048521A1 PCT/JP2023/030995 JP2023030995W WO2024048521A1 WO 2024048521 A1 WO2024048521 A1 WO 2024048521A1 JP 2023030995 W JP2023030995 W JP 2023030995W WO 2024048521 A1 WO2024048521 A1 WO 2024048521A1
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WO
WIPO (PCT)
Prior art keywords
resin sheet
foamed resin
edge
apparent density
width direction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/030995
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English (en)
French (fr)
Japanese (ja)
Inventor
敏晴 後藤
智史 山本
圭 水谷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maxell Ltd
Original Assignee
Maxell Ltd
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Filing date
Publication date
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Priority to JP2024544246A priority Critical patent/JPWO2024048521A1/ja
Publication of WO2024048521A1 publication Critical patent/WO2024048521A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/36—Feeding the material to be shaped
    • B29C44/46—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length
    • B29C44/50—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length using pressure difference, e.g. by extrusion or by spraying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/60—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/36—After-treatment

Definitions

  • the present disclosure relates to a foamed resin sheet that can be used as a molding material for vacuum molding, rolling molding, or the like.
  • Patent Document 1 JP 2019-98567A discloses a structure in which a skin sheet and a foamed resin sheet are integrally molded.
  • the foamed resin sheet constituting the structure is formed so that at least a portion of its outer periphery has a foaming ratio that gradually decreases toward the periphery.
  • the rigidity of at least a portion of the outer peripheral edge of the foamed resin sheet is improved, and burrs can be smoothly removed from the structure in which the skin sheet and the foamed resin sheet are integrally molded.
  • Patent Document 2 discloses an oriented laminated polyester film.
  • the oriented laminated polyester film is manufactured as follows. A film layer (A) made of polyester (A) and a film layer (B) made of polyester (B) are laminated, and polyester ( The unstretched sheet provided with the single-layer edge portion consisting of B) is extruded, stretched at least in the width direction, and then the single-layer edge portion is trimmed.
  • a film layer (A) made of polyester (A) and a film layer (B) made of polyester (B) are laminated, and polyester ( The unstretched sheet provided with the single-layer edge portion consisting of B) is extruded, stretched at least in the width direction, and then the single-layer edge portion is trimmed.
  • the resin used for each layer by specifying the resin used for each layer and their inherent viscosity, thickness unevenness that occurs at the boundary between the single layer part and the center part can be suppressed, and cutting This eliminates the problem of thickness and thinness, resulting in improved productivity.
  • JP 2008-246936A discloses a foam molded article.
  • the foam molded product is manufactured as follows in order to obtain a wide sheet-like foam molded product with a uniform expansion ratio.
  • a thermoplastic resin in which at least heat-swellable microcapsules are dispersed is extruded from an extruder equipped with a circular die to obtain a cylindrical thermoplastic resin, and then the cylindrical thermoplastic resin is expanded into a flat plate and at the same time 1.5 times or more It is foamed at a foaming ratio of .0 times or less, and then cooled and solidified.
  • JP 2020-185773A discloses a laminate.
  • the laminate includes a laminate portion including, in this order, a layer (A) containing a fiber-reinforced thermoplastic resin, a layer (B) containing a thermoplastic foamed resin, and a layer (C) containing a fiber-reinforced thermoplastic resin,
  • the (B) layer includes a low-density part where the apparent density is low and a high-density part where the apparent density is high and the ratio of the apparent density to the low-density part is 1.5 or more, and in plan view,
  • the total area of the laminated portion is 100%, the area of the low density portion is 50 to 90%, and the area of the high density portion is 10 to 50%. This provides a lightweight laminate with a high degree of freedom in shape.
  • the outer periphery of a foamed resin sheet is gripped and fixed by a clamp of a molding machine, and heated from above and below.
  • the desired shape is obtained by suctioning vacuum from inside the mold in vacuum forming, or by placing the foamed resin sheet along the mold and pressurizing it with compressed air in pressure forming. Form into shape.
  • the final part or product can be manufactured by trimming the excess portion of the molded article made of the foamed resin sheet.
  • the portion fixed by the above-mentioned clamp or the like that is, the gripping margin of the outer peripheral edge gripped by the clamp or the like is always removed.
  • the present inventors have found that by reducing the amount of resin contained in the gripping margin at the outer periphery of the foamed resin sheet, it is possible to reduce the amount of resin material discarded due to trimming.
  • the foamed resin sheet constituting the structure of Patent Document 1 is formed so that at least a portion of its outer periphery has a foaming ratio that gradually decreases toward the periphery, that is, the density of the resin increases toward the periphery. It is molded into. Therefore, there is a problem in that the amount of resin in the grip margin on the outer peripheral edge of the foamed resin sheet increases, and the amount of resin material discarded due to trimming increases.
  • the oriented laminated polyester film of Patent Document 2 includes single-layer edge portions at both ends. The edge single layer portion is trimmed. However, the oriented laminated polyester film suppresses the thickness spots that occur at the boundary between the edge single layer portion and the center portion, thereby improving productivity. Therefore, Patent Document 2 does not propose a reduction in the amount of resin material discarded due to trimming.
  • Patent Document 3 The foam molded article of Patent Document 3 is molded so that the expansion ratio is uniform. Therefore, Patent Document 3 does not propose a reduction in the amount of resin material discarded due to trimming.
  • the laminate of Patent Document 4 can include, in the laminate portion, a low-density portion in which the apparent density of the layer (B) is low, and a high-density portion in which the ratio of the apparent density to the low-density portion is 1.5 or more.
  • Patent Document 4 does not disclose the arrangement of the low-density portion, and does not propose a reduction in the amount of resin material discarded due to trimming.
  • An object of the present disclosure is to provide a foamed resin sheet that can reduce the amount of resin material wasted due to trimming after molding in molding methods such as vacuum molding and pressure molding.
  • the foamed resin sheet according to the present disclosure is a foamed resin sheet made of an extruded sheet, and includes one edge in the width direction extending along the extrusion direction of the foamed resin sheet and the opposite side of the one edge.
  • the foam resin sheet may include the other edge in the width direction extending along the extrusion direction of the foamed resin sheet, and a center portion located between one edge and the other edge.
  • One edge and at least a portion of the other edge may have a lower apparent density than the center.
  • foamed resin sheet according to the present disclosure it is possible to reduce the amount of resin material wasted due to trimming after molding in molding methods such as vacuum molding and pressure molding.
  • FIG. 1 is a perspective view showing a foamed resin sheet according to a first embodiment.
  • FIG. 2 is a sectional view of the foamed resin sheet shown in FIG. 1.
  • FIG. 3 is a sectional view showing how the foamed resin sheet shown in FIG. 1 is vacuum formed.
  • FIG. 4 is a sectional view showing how the foamed resin sheet shown in FIG. 1 is vacuum formed.
  • FIG. 5 is a sectional view showing a foamed resin sheet according to the second embodiment.
  • FIG. 6 is a sectional view showing a foamed resin sheet according to the third embodiment.
  • FIG. 7 is a sectional view showing a modified example of a foamed resin sheet.
  • FIG. 8 is a sectional view showing a modified example of a foamed resin sheet.
  • FIG. 9 is a sectional view showing a modified example of a foamed resin sheet.
  • FIG. 10 is a perspective view showing a wooden mold used for vacuum forming.
  • a foamed resin sheet according to an embodiment of the present disclosure is a foamed resin sheet made of an extruded sheet, and includes one edge in the width direction extending along the extrusion direction of the foamed resin sheet and an opposite edge of the one edge.
  • the foam resin sheet may include the other edge in the width direction extending along the extrusion direction of the foamed resin sheet on the side, and a center portion located between the one edge and the other edge.
  • One edge and at least a portion of the other edge may have a lower apparent density than the center.
  • One edge and the other edge become gripping margins that are fixed during vacuum forming or the like, and are removed by trimming after forming.
  • One edge and at least a portion of the other edge have a lower apparent density than the center. That is, the amount of resin at one edge and the other edge is smaller than that at the center. Thereby, it is possible to reduce the amount of resin material discarded due to trimming.
  • At least one of one edge and the other edge has an apparent density that is 15% to 50% lower than the apparent density of the central portion in the density distribution along the width direction. may have. This makes it possible to reduce the amount of waste resin material caused by trimming, and to ensure moldability during vacuum forming and the like.
  • one edge and the other edge may each have a length of 3 cm to 10 cm in the width direction. Thereby, the amount of waste resin material can be sufficiently reduced depending on the size of the foamed resin sheet and various molding machines.
  • one edge portion and the other edge portion may have an elastic modulus that is 10 to 70% lower than the elastic modulus of the central portion. Thereby, better vacuum formability of the foamed resin sheet can be ensured.
  • one edge portion and the other edge portion may have a thickness that is 10% or more smaller than the thickness of the center portion. Thereby, it is possible to further reduce the amount of resin material wasted due to trimming after molding.
  • the foamed resin sheet according to another embodiment is a foamed resin sheet made of an extruded sheet, wherein one edge in the width direction extending along the extrusion direction and the foamed resin sheet on the opposite side of the one edge. the other edge in the width direction extending along the extrusion direction, and a center portion located between the one edge and the other edge.
  • the weight per unit area of at least one of the one edge portion and the other edge portion is smaller than the weight per unit area of the central portion.
  • a foamed resin sheet according to another embodiment may include an outer periphery located at the outer periphery of the foamed resin sheet, and a central portion surrounded by the outer periphery. At least a portion of the outer periphery may have a lower apparent density than the central portion. Thereby, it is possible to reduce the amount of resin material discarded due to trimming.
  • the foamed resin sheet may further have a skin layer on either one of the main surfaces and the other main surface. Thereby, the strength of the foamed resin sheet can be improved, and the vacuum formability can be further improved.
  • the foamed resin sheet may be made of at least one of engineering plastics and super engineering plastics.
  • the foamed resin sheet may be made of polycarbonate resin.
  • FIGS. 1 to 4 a first embodiment of the foamed resin sheet 1 of the present disclosure will be specifically described using FIGS. 1 to 4.
  • the same reference numerals are attached to the same or corresponding components in the figures, and the same explanations will not be repeated. Note that, in order to make the explanation easier to understand, in the drawings referred to below, the configuration is shown in a simplified or schematic manner, and some structural members are omitted.
  • the foamed resin sheet 1 is an extruded sheet formed by an extrusion method. As shown in FIG. 1, it has an edge part 2, an edge part 3 and a central part 4.
  • the foamed resin sheet 1 is made of thermoplastic resin, preferably polycarbonate resin.
  • the resin used for the foamed resin sheet 1 of the present disclosure can be variously selected from various resin materials such as general-purpose plastics, engineering plastics, and super engineering plastics. However, from the viewpoint of improving heat resistance and strength and expanding the scope of use, it is preferable to use engineering plastics and super engineering plastics.
  • Engineering plastics that can be used in the present disclosure include, for example, polyamide (PA), polycarbonate (PC), polyacetal (POM), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), glass fiber reinforced polyethylene terephthalate (GF-PET), ultra-high molecular weight polyethylene (UHPE), and syndiotactic polystyrene (SPS).
  • super engineering plastics include polyphenylene sulfide (PPS), polysulfone (PSF), polyether sulfone (PES), polyarylate (PAR), polyamideimide (PAI), thermoplastic polyimide (PI), and polyetherimide (PEI). , liquid crystal polymer (LCP).
  • various alloy materials or copolymers of the above-mentioned engineering plastics and super engineering plastics may be used, and organic fillers or inorganic fillers may be included.
  • organic fillers or inorganic fillers may be included.
  • polycarbonate from the viewpoints of formability, cost efficiency, and low-temperature impact resistance, it is preferable to contain polycarbonate, and from the viewpoints of strength, cost efficiency, and foamability, it is preferable to contain polyphenylene sulfide.
  • the edge portion 2 is one end portion in the width direction TD extending along the extrusion direction MD. That is, the edge portion 2 is a region extending along the extrusion direction MD at one end side in the width direction TD.
  • the extrusion direction MD is the direction in which the foamed resin sheet 1 is extruded during extrusion molding, and usually corresponds to the longitudinal direction of the extruded molded product (foamed resin sheet 1), and the extruded polymer molecules and This corresponds to the direction of bubble orientation.
  • the bubbles contained in the foamed resin sheet 1 have a substantially elliptical spherical shape extending along the extrusion direction MD.
  • the edge portion 2 serves as one gripping margin for fixing the foamed resin sheet 1 to a molding machine when the foamed resin sheet 1 is subjected to vacuum forming, pressure forming, or the like.
  • the gripping allowance will be described later with reference to FIGS. 3 and 4, together with how the foamed resin sheet 1 is vacuum-formed into a desired shape.
  • the edge portion 3 is located at the edge in the width direction opposite to the edge portion 2, and is the other end in the width direction TD extending along the extrusion direction MD. That is, the edge portion 3 is a region extending along the extrusion direction MD on the other end side in the width direction TD.
  • the edge portion 3 serves as the other gripping margin for fixing the foamed resin sheet 1 to a molding machine when the foamed resin sheet 1 is subjected to vacuum forming, pressure forming, or the like. That is, the foamed resin sheet 1 is fixed to the molding machine by having the clamp of the molding machine grip the gripping margin.
  • the gripping margin is the outer peripheral edge (four sides) of the foamed resin sheet 1 including the edge 2 and the edge 3.
  • the central portion 4 is located between the edge portions 2 and 3. As will be described later, a portion of the central portion 4 is deformed into a desired shape by a mold during vacuum forming or pressure forming. Note that the two-dot chain line in the figure indicates the boundary between the edge portion 2 and the center portion 4, and the boundary between the edge portion 3 and the center portion 4. Moreover, in this embodiment, the central portion 4 is a portion located between the edge portions 2 and 3 in the width direction.
  • the edge portions 2 and 3 have a lower apparent density than the central portion 4. That is, the foaming ratio of the edge portions 2 and a portion of the edge portions 3 is higher than that of the center portion 4.
  • the foaming ratio can be calculated by ( ⁇ 1/ ⁇ 2), where the apparent density before foaming is ⁇ 1 and the apparent density after foaming is ⁇ 2.
  • FIG. 2 is a cross-sectional view of the foamed resin sheet 1 cut in the thickness direction along the width direction TD.
  • the apparent density of the edge portions 2 is 15% to 50% lower than that of the central portion 4.
  • the apparent density of the edge portions 3 is 15-50% lower than the apparent density of the central portion 4. If the apparent density of the edge portion 2 or edge portion 3 is too lower than the apparent density of the center portion 4, the strength of the edge portion 2 or edge portion 3 will decrease, so the edge portion may be used as a gripping margin during vacuum forming. There is a risk that the portion 2 or the edge portion 3 may be damaged or easily bent during heating, resulting in reduced vacuum formability.
  • the apparent density of the edge portions 2 or 3 is 15% lower than that of the center portion 4. % or more, preferably 20% or more, more preferably 25% or more, and 50% or less, preferably 45% or less, more preferably 40% or less.
  • the apparent density of each of the edge portions 2, edge portions 3, and center portion 4 is calculated as follows by measuring the density distribution in the width direction TD.
  • the foamed resin sheet 1 is cut in a direction parallel to the width direction TD, and a sheet piece having a length of 12 cm is cut in the MD direction parallel to the extrusion direction.
  • the length of the sheet piece in the width direction TD depends on the length of the extruded foamed resin sheet 1 in the width direction TD.
  • a plurality of strips are created by cutting the sheet piece at intervals of 2 cm from the center of the sheet piece in the width direction TD toward both ends in the width direction TD.
  • each of the plurality of strips has a length of 12 cm in the extrusion direction MD and a length of 2 cm in the width direction TD.
  • the plurality of strips may include strips having a length of less than 2 cm at both ends in the width direction TD (cut ends at both ends in the width direction TD). Such strips having a length of less than 2 cm are not used in the calculation of apparent density below.
  • the apparent density of each strip is calculated using the following formula.
  • ⁇ w/(d ⁇ L1 ⁇ L2)
  • ⁇ indicates the apparent density
  • w indicates the weight of the strip
  • d indicates the thickness of the strip
  • L1 indicates the length of the strip in the extrusion direction MD
  • L2 indicates the length of the strip in the width direction TD. shows.
  • the thickness d of the strip is determined as follows. First, in plan view, a center line extending in the extrusion direction MD is drawn along the center of the strip in the width direction TD. The length of the center line is 12 cm, which is the same as the length of the strip in the extrusion direction MD. Next, the thickness of the strip is measured at five points on the center line at 2 cm intervals excluding both ends.
  • the average value of the thicknesses of these five points is defined as the thickness d of the strip.
  • the apparent density of the edge portion 2 can be calculated from the average value of the apparent densities of the strips included in the edge portion 2.
  • the apparent density of the edge portion 3 can be calculated from the average value of the apparent densities of the strips included in the edge portion 3.
  • the apparent density of the central portion 4 can be calculated from the average value of the apparent densities of the strips included in the central portion 4. Note that the strip including the boundary between the edge portion 2 and the center portion 4 and the strip including the boundary between the edge portion 3 and the center portion 4 are not used in the above-mentioned calculation of the apparent density.
  • the vacuum forming machine 100 includes a clamp 101 for fixing the foamed resin sheet 1, a heater 102 for heating and plasticizing the foamed resin sheet 1, and a mold 103 shown in FIG.
  • the clamp 101 grips the edge portions 2 and 3 of the foamed resin sheet 1 . That is, in the foamed resin sheet 1, the width indicated by arrow A becomes the gripping margin. Thereby, the foamed resin sheet 1 is fixed to the clamp 101. Next, the foamed resin sheet 1 (particularly the central portion 4) is heated by the heater 102 from above and below. As shown in FIG.
  • the mold 103 is moved downward to the foamed resin sheet 1, and vacuum suction is applied from inside the mold 103, so that the foamed resin sheet 1 mold into the desired shape.
  • the deformed foamed resin sheet 1 is cooled and solidified, and then released from the mold 103.
  • unnecessary portions of the deformed foamed resin sheet 1, including the edge portions 2 and 3, are trimmed. In this way, parts or finished products can be manufactured using the foamed resin sheet 1 as a material.
  • the width A of the gripping allowance varies depending on the size of the foamed resin sheet 1 in plan view and various molding machines. Therefore, the length of the edge portion 2 or edge portion 3 in the width direction TD shown in FIG. The height should be between 3cm and 10cm. Thereby, the amount of waste resin material can be sufficiently reduced depending on the size of the foamed resin sheet 1 and various molding machines.
  • the air bubbles contained in the foamed resin sheet 1, which is an extruded sheet tend to extend in the extrusion direction during extrusion molding. That is, the bubbles tend to have an ellipsoidal shape with a long axis along the extrusion direction (not shown). If ellipsoidal bubbles extending in the extrusion direction exist near the inner end of the gripping margin, stress will concentrate near the inner end of the gripping margin during vacuum forming, making the foamed resin sheet 1 more likely to be damaged or buckled. That is, the vacuum formability of the foamed resin sheet 1 is reduced.
  • the length of the bubbles included in the width region W is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 12 mm or less. Thereby, the vacuum formability of the foamed resin sheet 1 can be sufficiently ensured.
  • the length of the bubbles included in the width region W is preferably 0.1 mm or more, preferably 0.2 mm or more, and more preferably 0.4 mm or more.
  • the length of the bubble refers to the distance between the line segments that connect the farthest vertices of the contour forming the stretched bubble.
  • the air bubbles are considered to have the same effect on the foamed resin sheet 1 as cracks.
  • the foamed resin sheet 1 accumulates elastic strain energy in tension in proportion to the square of 1/2 the length of the crack, and becomes more likely to break.
  • the foamed resin sheet 1 since the outer peripheral surface side of the bend R is in tension, it is thought that the same concept as the Griffith theory is possible. Therefore, the longer the length of the bubbles contained in the foamed resin sheet 1, the easier the foamed resin sheet 1 will be to break.
  • the edge portions 2 and 3 have an elastic modulus that is 10 to 70% lower than the elastic modulus of the central portion 4. Note that the elastic modulus of either the edge portion 2 or the edge portion 3 may be lower than the elastic modulus of the central portion 4 by 10 to 70%. Thereby, vacuum formability can be ensured. If the elastic modulus of the edge portion or the edge portion 3 (gripping margin) is too lower than the elastic modulus of the central portion 4, the gripping margin will easily bend, making it difficult to fix the foamed resin sheet 1 with a clamp.
  • the elastic modulus of the edge portion or the edge portion 3 is preferably lower than the elastic modulus of the central portion 4 by 10% or more, preferably 20% or more, more preferably 30% or more, and 70% or less, It is preferable to lower it by 60% or less, more preferably by 50% or less.
  • a coat hanger die (hereinafter referred to as die) is attached to the extrusion molding machine.
  • the resin material is put into an extrusion molding machine, and while melting, a foaming agent is injected and stirred. Thereafter, the molten resin in which the foaming agent is dispersed is discharged from the die.
  • the apparent density of the edge portions 2, 3, and center portion 4 is adjusted by the shape of the manifold, the temperature distribution in the width direction of the coat hanger die, and the choke bar. More specifically, when the temperature of the die is lowered, the expansion ratio of the foamed resin sheet 1 becomes smaller and the apparent density becomes higher.
  • the foamed resin sheet 1 of the present disclosure can be manufactured by appropriately adjusting the expansion ratio (apparent density) and thickness of the edge portions 2, 3, and the center portion. Note that the foamed resin sheet 1 discharged from the die is cooled and solidified, and then cut into a desired length.
  • the thickness of the edge portions 2 and 3 is smaller than the thickness of the center portion 4.
  • the thickness of either the edge portion 2 or the edge portion 3 may be smaller than the thickness of the center portion 4.
  • the thickness of either the edge portion 2 or the edge portion 3 is smaller than the thickness of the center portion 4 by 10% or more. Thereby, it is possible to reduce the amount of resin material discarded due to trimming.
  • the thickness of the edge portion 2 or the edge portion 3 is preferably 10% or more, preferably 13% or more smaller than the thickness of the center portion 4. , 30% or less, preferably 20% or less, more preferably 15% or less.
  • the foamed resin sheet 1 of the third embodiment will be specifically described with reference to FIG. 1.
  • a plan view of the foamed resin sheet 1 that is, when looking at the main surface of the foamed resin sheet 1 from above, at least one of the edge portions 2 and 3 per unit area of the center portion 4. has a weight per unit area that is less than the weight of In other words, the weight per unit area of at least one of the edge portions 2 and 3 is smaller than the weight per unit area of the central portion 4. Thereby, it is possible to reduce the amount of resin material discarded due to trimming.
  • the foamed resin sheet 1 of the third embodiment can include the foamed resin sheet 1 in which at least a portion of the edge portions 2 and 3 have a lower apparent density than the center portion 4, and Includes a foamed resin sheet 1 in which the end portions 2, the edge portions 3, and the center portion 4 have the same apparent density, and at least one of the edge portions 2 and the edge portions 3 has a smaller thickness than the center portion 4. Can be done.
  • the weight per unit area of the edge portion 2, edge portion 3, and center portion 4 can be calculated as follows. First, as in the case of calculating the above-mentioned apparent density, a plurality of strips are created. For each strip, the weight per unit area (W/S) is calculated based on the area S in plan view and the weight W of the strip.
  • the weight per unit area of the edge part 2 can be calculated from the average value of the weights per unit area of the strips included in the edge part 2.
  • the weight per unit area of the edge part 3 can be calculated from the average value of the weights per unit area of the strips included in the edge part 3.
  • the weight per unit area of the central part 4 can be calculated from the average value of the weights per unit area of the strips included in the central part 4.
  • the plurality of strips may include strips (cut ends at both ends in the width direction TD) having a length of less than 2 cm at both ends in the width direction TD. Such strips having a length of less than 2 cm are not used in calculating the weight per unit area. Further, the strip including the border between the edge portion 2 and the center portion 4 and the strip including the border between the edge portion 3 and the center portion 4 are also not used in calculating the weight per unit area.
  • the foamed resin sheet 1 further has a skin layer 5 on its main surface.
  • the skin layer 5 is formed on at least one of one main surface and the other main surface of the foamed resin sheet 1.
  • the skin layer 5 is made of non-foamed resin. That is, the skin layer 5 is not foam-molded.
  • the skin layer 5 may be integrally laminated with the foamed resin sheet 1 of the first embodiment by a coextrusion method. Alternatively, a skin layer 5 separately formed into a sheet shape may be formed so as to be adhered to the main surface of the foamed resin sheet 1.
  • a thermoplastic resin that can be well bonded to the foamed resin sheet 1 may be used.
  • the resin material of the skin layer 5 is the same resin material as the foamed resin sheet 1 of the first embodiment.
  • the skin layer 5 may contain, for example, inorganic fillers such as glass fiber, carbon fiber, aramid fiber, talc, and mica. Thereby, the strength of the foamed resin sheet 1 can be improved, and the vacuum formability can be further improved.
  • the foamed resin sheet 1 may be provided with a skin layer 5 on the main surface of the central portion 4. At this time, the skin layer 5 is not formed on the edge portions 2 and 3.
  • the combined thickness of the center portion 4 and the skin layer 5 and the thickness of the edge portion 2 or edge portion 3 are approximately the same.
  • the foamed resin sheet 1 may be provided with a skin layer 5 only on the main surface of the central portion 4.
  • the combined thickness of the center portion 4 and the skin layer 5 is greater than the thickness of the edge portion 2 or the edge portion 3.
  • the thickness of each of the center part 4, the edge part 2, and the edge part 3 is substantially the same.
  • the foamed resin sheet 1 may include an outer peripheral portion located at the outer peripheral edge and a central portion surrounded by the outer peripheral portion. At least a portion of the outer periphery may have a lower apparent density than the central portion. Similar to the edge portions 2 and 3 described above, the outer peripheral portion has a lower apparent density than the central portion in a portion thereof. Therefore, the outer peripheral portion can be used as a gripping margin during vacuum forming. Therefore, the outer circumferential portion and the above-mentioned edge portion 2 are substantially the same, and a detailed explanation of the outer circumferential portion will be omitted.
  • the foamed resin sheet 1 can contribute to improving resource utilization efficiency, reducing energy consumption, and reducing CO2 emissions.
  • Goal 7 Available and Clean Energy
  • Goal 9 Industry and Technology
  • SDGs 17 Sustainable Development Goals
  • foamed resin sheets of Examples 1 to 7 and Comparative Example 1 were produced, and the amount of waste and vacuum formability of each was evaluated.
  • Each foamed resin sheet was produced to have a widthwise length of 1.3 m by extruding polycarbonate (Panlite L1225Y, manufactured by Teijin) at an extrusion temperature of 220°C using an extrusion molding machine. At this time, the apparent density, etc. of each foamed resin sheet was adjusted according to the above-mentioned manufacturing method.
  • the "reduction rate of elastic modulus at both ends” in Table 1 below indicates the degree of lower density of the edge portions relative to the elastic modulus of the center portion as a percentage, and is a value obtained by rounding the value to the first decimal place.
  • the "both ends density reduction rate” indicates the degree of lower apparent density at the edges relative to the apparent density at the center as a percentage, and is a value obtained by rounding the value to the first decimal place.
  • “Both end cell length” is the length of the cell included in a width region of 10 to 20 from each edge in the width direction, when the entire width direction of the foamed resin sheet is taken as 100.
  • “Thickness at both ends” indicates the degree of decrease in the thickness at the edge portions relative to the thickness at the center portion, expressed as a percentage, and is a value obtained by rounding the value to the first decimal place. "Width at both ends” is the width of the portion at the edge where the apparent density is 20% or more lower than the apparent density at the center.
  • “both ends” in “Both ends density reduction rate”, “Both ends elastic modulus reduction rate”, “Both ends width” and “Both ends thickness” in Table 1 refers to the difference between one edge and the other edge. It is an average value, and for example, “density reduction rate at both ends” is the average of the degree of low density of one edge with respect to the center and the degree of low density of the other edge with respect to the center. It is a value.
  • Waste reduction index (1-(1-A/100) x (1-C/100)) x 100 x B
  • A represents the density reduction rate (%) at both ends in Table 1
  • B represents the width at both ends (cm) in Table 1
  • C represents the thickness at both ends (%) in Table 1. Show value. It was determined that the larger the value of the waste reduction index calculated in this way, the greater the effect of reducing the amount of waste.
  • a wooden mold 104 was prepared.
  • the wooden mold 104 is a male mold having a truncated quadrangular pyramid shape.
  • the bottom surface of the wooden mold 104 is square, and the length L of one side is 150 mm. Further, the height h of the wooden pattern 104 is 50 mm, and the inclination angle ⁇ of the side surface is 7°.
  • This wooden mold 104 was continuously heated at 80°C, and each foamed resin sheet was heated from above and below with an infrared heater so that the surface temperature of each foamed resin sheet was 200°C.
  • the foamed resin sheets of Examples 1 to 7 have a larger apparent density reduction rate at the edge than the foamed resin sheet of Comparative Example 1, that is, the apparent density of the edge is smaller than that of the center, so the amount of waste can be reduced. We were able to reduce this significantly.
  • the "bubble length at both ends" of Examples 1 to 7 was confirmed.
  • the cell length at both ends was 20 mm, there were cases in which vacuum forming was possible using plug assist as in Example 5, and cases in which vacuum formability was poor as in Examples 4 and 6. That is, when the cell length at both ends exceeded 20 mm, the result was that vacuum forming was inferior. In this way, by setting the cell length at both ends to 20 mm or less, it was possible to reduce the amount of waste and ensure vacuum formability. In particular, when the cell length at both ends was 12 mm or less, excellent vacuum formability could be ensured.
  • the “reduction rate of elastic modulus at both ends” of Examples 1 to 7 was confirmed.
  • the elastic modulus reduction rate at both ends was 10% to 70%, it was possible to reduce the amount of waste and ensure vacuum formability.
  • the elastic modulus reduction rate at both ends was set to 50% or less, better vacuum formability could be ensured.
  • Example 1 The "thickness at both ends” of Examples 1 to 7 was confirmed. Comparing Examples 1 to 6 and Example 7, it was found that if the "thickness at both ends" was 10% or more, the amount of waste could be reduced relatively significantly. On the other hand, when comparing Example 1 and Example 7, which differ only in the condition of "thickness at both ends", when the "thickness at both ends" reached 30%, the evaluation of vacuum formability was "B". Further, in Example 4 in which the "thickness at both ends" was 30%, the evaluation of vacuum formability was "B". In this way, by setting the "thickness at both ends” to 10% or more, the amount of waste could be reduced, and by setting it to 30% or less, vacuum formability could be ensured.

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  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0592745A (ja) * 1991-07-23 1993-04-16 Nippon Plast Co Ltd エアバツグカバー体
JPH0948054A (ja) * 1995-08-08 1997-02-18 Jsp Corp 熱成形用ポリスチレン系樹脂発泡シートロール
JP2001138383A (ja) * 1999-11-10 2001-05-22 Kanegafuchi Chem Ind Co Ltd ポリスチレン系樹脂発泡シート及びその製造方法
JP2021535862A (ja) * 2018-09-04 2021-12-23 ハンファ アズデル インコーポレイテッド 可変坪量を有するコア層及び複合品

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0592745A (ja) * 1991-07-23 1993-04-16 Nippon Plast Co Ltd エアバツグカバー体
JPH0948054A (ja) * 1995-08-08 1997-02-18 Jsp Corp 熱成形用ポリスチレン系樹脂発泡シートロール
JP2001138383A (ja) * 1999-11-10 2001-05-22 Kanegafuchi Chem Ind Co Ltd ポリスチレン系樹脂発泡シート及びその製造方法
JP2021535862A (ja) * 2018-09-04 2021-12-23 ハンファ アズデル インコーポレイテッド 可変坪量を有するコア層及び複合品

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