Feeder for filling bead, mold for molding bead foam, bead foam, and method for manufacturing bead foam

Abstract

According to the present invention, in the production of a bead foam, in particular a bead foam as a thin-walled molded article, a bead foam having a complete shape without defects is produced. In the feeder for filling beads, the length of a plunger tube at the front end part of the feeder is more than 10 mm and less than 40 mm, and the inclination angle of an inclined flow path at the front end part of the feeder is more than 10 degrees and less than 30 degrees.

Description

Technical Field

[0001] The present invention relates to a feeder for bead filling, a mold for molding a bead foam, a bead foam, and a method for producing the bead foam. Background Art

[0002] Resin bead foams are molded articles made from expanded resin beads. Due to the properties of the resin, these articles are expected to have a wide range of applications as molded articles exhibiting properties such as flame retardancy, heat resistance, insulation, and high dimensional accuracy. For example, Patent Documents 1 and 2 describe feeders used to blow the expanded resin beads into a mold when molding articles made from expanded resin beads. Patent Documents 3 to 5 propose molds that can be used to mold articles made from expanded resin beads.

[0003] Resin bead foams are used in a variety of applications, and demand for thin-walled molded articles made of resin bead foam is increasing, particularly for applications such as automotive and wireless communications. When attempting to mold the resin bead foam in a mold by blowing the raw resin foam beads into a mold using a feeder, localized filling defects are prone to occur. Especially when molding thin-walled molded articles, the area near the feeder is prone to forming defects (holes), making it difficult to obtain thin-walled molded articles with shapes sufficient for automotive and wireless communications applications.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-001359

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-104784

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 07-178749

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 11-020027

[0010] Patent Document 5: Japanese Patent Application Laid-Open No. 2001-198940 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] The present invention has been completed in view of the above situation, and its purpose is to provide a feeder used for filling raw material beads into a molding mold for a bead foam (for example, a bead foam as a thin-walled molded product), a molding mold for such a bead foam, a bead foam molded using such a mold, and a method for manufacturing such a bead foam, wherein the bead foam has a complete shape without defects, and in particular, no filling defects will occur in the part near the feeder of the mold.

[0013] Means for solving problems

[0014] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that, when manufacturing bead foam using a mold having multiple feeders, by using a feeder having a plunger tube length of 10 mm to 40 mm at the front end portion and an inclined flow path at the front end portion of the feeder having an inclination angle of 10 degrees to less than 30 degrees, a bead foam having a perfect shape without defects, particularly a bead foam as a thin-walled molded article, can be manufactured. Furthermore, by molding the bead foam using a mold having a molding material-filled space having a pair of opposing surfaces, one of the pair of surfaces having a feeder and the other having a vent plug, wherein a region on the one surface where at least one feeder is present and a region on the other surface where at least one vent plug is present overlap in a vertically spaced view relative to the opposing surfaces, the present inventors have completed the present invention.

[0015] That is, the present invention is as follows. [1]

[0017] A feeder for bead filling, wherein:

[0018] The length of the plunger tube at the front end of the feeder is not less than 10 mm and not more than 40 mm.

[0019] The inclined flow path at the front end portion of the feeder has an inclination angle of 10 degrees or more and less than 30 degrees. [2]

[0021] The feeder for bead filling as described in [1], wherein the intersection distance of the inclined flow path at the front end portion of the feeder is 0 mm or more and 20 mm or less. [3]

[0023] The feeder for bead filling as described in [1] or [2], wherein the front end portion of the feeder has a slit. [4]

[0025] A bead foamed body comprising a resin, wherein:

[0026] The beads foam body has one or more portions corresponding to discharge marks of a feeder during molding of the beads foam body.

[0027] The thinnest thickness of the portion corresponding to the feeder discharge mark is 5 mm or less. [5]

[0029] The beads foam as described in [4], wherein a thickness of a portion of the beads foam is 60 mm or less.

[0030] [5a]

[0031] A bead foamed body comprising a resin, wherein:

[0032] The beads foam body has one or more portions corresponding to the discharge port of the feeder during molding of the beads foam body.

[0033] The thickness of the molding material-filled space at the portion where at least one of the discharge ports of the feeder exists is 5 mm or less,

[0034] The thickness of the portion of the space filled with the molding material is not less than 2 mm and not more than 60 mm. [6]

[0036] The beads foam according to any one of [4] to [5a], wherein

[0037] The bead foam body has a pair of opposite surfaces.

[0038] One of the pair of surfaces has a portion corresponding to a discharge trace of a feeder during bead foam molding.

[0039] The other side has a portion corresponding to the trace of the air plug when the beads are formed.

[0040] In a viewing angle perpendicular to the one surface, part or all of a portion corresponding to at least one vent plug mark on the other surface exists within the region occupied by the feeder discharge mark.

[0041] [6a]

[0042] A bead foam comprising a resin, wherein the bead foam has one or more portions corresponding to a discharge outlet of a feeder during bead foam molding, and the thinnest thickness of at least one of the portions corresponding to the discharge outlet of the feeder is 5.0 mm or less.

[0043] [6b]

[0044] The bead foam as described in [6a], wherein

[0045] The bead foam body has a pair of opposite surfaces.

[0046] One of the pair of surfaces has one or more portions corresponding to the discharge ports of the feeder during bead foam molding.

[0047] The other side has a portion that corresponds to the air plug when the beads are formed.

[0048] In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface exists within a region occupied by at least one of the portions corresponding to the discharge port of the feeder. [7]

[0050] The beads foam according to any one of [4] to [6b], wherein

[0051] The bead foam body has a flow channel portion that is cut off during use.

[0052] The flow channel portion includes a portion corresponding to the discharge trace of the feeder during molding of the beads foam.

[0053] [7a]

[0054] The beads foam according to any one of [4] to [7], wherein

[0055] The bead foam body has a flow channel portion that is cut off during use.

[0056] The flow channel portion includes at least one of the portions corresponding to the discharge port of the feeder during molding of the beads foam. [8]

[0058] The beads foam as described in [7] or [7a] is characterized by the following (A) or (B):

[0059] (A) the flow channel portion exists in a direction perpendicular to the plane of the beads foam;

[0060] (B) The flow channel portion exists within the plane of the beads foam.

[0061] [8a]

[0062] The beads foam body as described in [8], wherein the flow channel portion exists in a direction perpendicular to the plane of the beads foam body.

[0063] [8b]

[0064] The bead foam body as described in [8], wherein the flow channel portion exists within the plane of the bead foam body. [9]

[0066] The beads foam according to any one of [4] to [8b], wherein the feeder discharge mark during molding of the beads foam has an air hole mark.

[0067] [9a]

[0068] The beads foam according to any one of [4] to [9], wherein a slit mark is present on at least one periphery of the portion corresponding to the discharge port of the feeder during molding of the beads foam.

[10]

[0070] The beads foam according to any one of [4] to [9a], wherein the flatness of the expanded beads (per 1 cm of the portion corresponding to the feeder discharge mark measured on the cross section of the expanded beads) in the portion corresponding to the feeder discharge mark during molding of the beads foam is 2 The average value of ((maximum value of in-plane diameter−maximum value of thickness direction diameter) / maximum value of in-plane diameter) in the cross section is 0.7 or less.

[0071] [10a]

[0072] The beads foam according to any one of [4] to

[10] , wherein the flatness of the expanded beads at at least one of the portions corresponding to the discharge outlet of the feeder during molding of the beads foam (per 1 cm of the portion corresponding to the feeder discharge outlet measured on the cross section of the expanded beads) is 2 The average value of ((maximum value of in-plane diameter−maximum value of thickness direction diameter) / maximum value of in-plane diameter) in the cross section is 0.7 or less.

[11]

[0074] The bead foam according to [4] or 5, wherein the number of expanded beads in the thickness direction of the bead foam (per 1 cm of the portion corresponding to the feeder discharge outlet measured on the cross section of the bead foam) is 2 The average number of expanded beads in the thickness direction in the cross section is 1.2 or more and 15 or less.

[0075] [11a]

[0076] The bead foam according to any one of [4] to

[11] , wherein, with respect to at least one of the portions corresponding to the discharge outlet of the feeder, the number of expanded beads in the thickness direction of the bead foam (per 1 cm of the portion corresponding to the discharge outlet of the feeder measured on the cross section of the bead foam) is 2The average number of expanded beads in the thickness direction in the cross section is 1.2 or more and 15 or less.

[12]

[0078] The beads foam according to any one of [4] to [11a], wherein the ratio of the density of the portion corresponding to the feeder discharge port trace during molding of the beads foam to the average density of the entire beads foam molded product is 110 to 300%.

[13]

[0080] The beads foam according to any one of [4] to [11a], wherein the ratio of the elastic modulus of the portion corresponding to the feeder discharge port trace during molding of the beads foam to the average elastic modulus of the entire beads foam molded product is 120 to 600%.

[0081] [13a]

[0082] The beads foam according to any one of [4] to

[13] , wherein a slit mark is present on at least one periphery of the portion corresponding to the discharge port of the feeder during molding of the beads foam.

[14]

[0084] A mold for bead foam molding, characterized by the following (A) or (B).

[0085] (A) The molding material filling space of the mold has a pair of opposing surfaces,

[0086] The above molding material filling space is connected to the feeder,

[0087] One of the pair of surfaces has a discharge port of the feeder,

[0088] The other side has a breathable plug.

[0089] The thickness of the molding material filling space at the discharge port of the feeder is 5 mm or less.

[0090] In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface is present within the area occupied by the discharge port of the feeder;

[0091] (B) The molding material-filled space of the mold has a portion corresponding to the runner portion of the beads foam molded by the mold that is cut away during use.

[0092] The above part corresponding to the runner part has the feeder discharge trace,

[0093] The thickness of the molding material-filled space at the portion where the discharge port of the feeder exists is 5 mm or less.

[0094] [14a]

[0095] A mold for molding a bead foam body, wherein:

[0096] The molding material filling space of the mold has a pair of opposite surfaces.

[0097] The above molding material filling space is connected to one or more feeders,

[0098] One of the pair of surfaces has a discharge port of the feeder at one or more locations.

[0099] The other side has a breathable plug.

[0100] The thickness of the molding material-filled space at the portion where at least one of the discharge ports of the feeder exists is 5 mm or less,

[0101] In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface exists within a region occupied by at least one discharge port of the feeder.

[0102] [14b]

[0103] A mold for molding a bead foam body, wherein:

[0104] The molding material filling space of the mold has a portion corresponding to the runner portion of the bead foam molded by the mold that is cut off during use.

[0105] The portion corresponding to the flow channel portion has at least one of the discharge ports of the feeder.

[0106] The thickness of the molding material-filled space in a portion where at least one of the discharge ports of the feeder is present is 5 mm or less.

[15]

[0108] A mold for molding beads foam, wherein the molding material filling space of the mold has a pair of opposite surfaces,

[0109] The above molding material filling space is connected to one or more feeders,

[0110] One of the pair of surfaces has a discharge port of the feeder at one or more locations.

[0111] One or more of the feeders are the feeders described in any one of [1] to [3].

[0112] [15a]

[0113] A mold for molding a bead foam body, wherein:

[0114] The molding material filling space of the mold has a pair of opposite surfaces.

[0115] The above molding material filling space is connected to two or more feeders,

[0116] One of the pair of surfaces has discharge outlets of the feeder at two or more locations.

[0117] One or more of the feeders are the feeders described in any one of [1] to [3].

[0118] [15b]

[0119] A mold for molding a bead foam body, wherein:

[0120] The molding material filling space of the mold has a pair of opposite surfaces.

[0121] The above molding material filling space is connected to two or more feeders,

[0122] One of the pair of surfaces has discharge outlets of the feeder at two or more locations.

[0123] The thickness of the molding material-filled space at the portion where at least one of the discharge ports of the feeder exists is 5 mm or less,

[0124] The thickness of the portion of the space filled with the molding material is not less than 2 mm and not more than 60 mm.

[16]

[0126] The beads foam molding die according to any one of

[14] to [15b], further comprising a vent hole near the discharge port of the feeder.

[0127] [16a]

[0128] The beads foam molding die according to any one of

[14] to

[16] , wherein a slit hole is present near at least one of the discharge ports of the feeder.

[17]

[0130] A method for producing a bead foam comprises the following steps:

[0131] A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and

[0132] The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body.

[0133] This production method is characterized by the following (A) or (B).

[0134] (A) The molding material filling space of the mold has a pair of opposing surfaces,

[0135] One of the pair of surfaces has a discharge port of the feeder,

[0136] The other side has a breathable plug.

[0137] The thickness of the molding material filling space at the discharge port of the feeder is 5 mm or less.

[0138] In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface is present within the area occupied by the discharge port of the feeder;

[0139] (B) The molding material-filled space of the mold has a portion corresponding to the runner portion of the beads foam molded by the mold that is cut away during use.

[0140] The portion corresponding to the flow channel has a discharge port of the feeder.

[0141] The thickness of the molding material-filled space at the portion where the discharge port of the feeder exists is 5 mm or less.

[18]

[0143] A manufacturing method comprising the following steps:

[0144] A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and

[0145] The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body.

[0146] The molding material filling space of the above-mentioned mold has a pair of opposite surfaces.

[0147] One of the pair of surfaces has a discharge port of the feeder at one or more locations.

[0148] The intersection point of the inclined flow path of the feeder is present in the molding material filling space.

[0149] [18a]

[0150] A method for producing a bead foam comprises the following steps:

[0151] A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and

[0152] The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body.

[0153] in,

[0154] The molding material filling space of the above-mentioned mold has a pair of opposite surfaces.

[0155] One of the pair of surfaces has a discharge port of the feeder at one or more locations.

[0156] The other side has a breathable plug.

[0157] The thickness of the molding material-filled space at the portion where at least one of the discharge ports of the feeder exists is 5 mm or less,

[0158] In a viewing angle perpendicular to the one surface, at least one of the opening in the vent plug and the discharge port of the feeder has an overlapping region in a viewing angle perpendicular to the opposing surface.

[0159] [18b]

[0160] A method for producing a bead foam comprises the following steps:

[0161] A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and

[0162] The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body.

[0163] in,

[0164] The molding material filling space of the above-mentioned mold has a portion corresponding to the flow channel portion of the bead foam molded by the mold that is cut off when in use.

[0165] The portion corresponding to the flow channel portion has at least one of the discharge ports of the feeder.

[0166] The thickness of at least one molding material-filled space in the portion where the discharge port of the feeder is located is 5 mm or less.

[19]

[0168] The method for producing a beads foam according to any one of

[17] to [18b], wherein the feeder has a vent hole near the discharge port.

[0169] [19a]

[0170] The method for producing a beads foam according to any one of

[17] to

[19] , wherein a slit hole is present near at least one of the discharge ports of the feeder.

[0171] Effects of the Invention

[0172] According to the present invention, in the production of beads foam, particularly thin-walled molded articles, beads foam having a flawless, perfect shape can be produced. In particular, the thin-walled molded articles produced in this manner are suitable for use in automotive applications, wireless communications, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0173] Figure 1 An example of a schematic diagram of a feeder (1) of the present invention is shown.

[0174] Figure 2 An example of a schematic diagram showing the periphery of the front end portion (2) of the feeder (1) of the present invention.

[0175] Figure 3 An example of a schematic diagram showing the feeder (1) of the present invention when in use.

[0176] Figure 4 An example of a schematic diagram of the feeder (1) of the present invention in the case of having a vent hole (slit) (2c) is shown.

[0177] Figure 5 An example of a schematic diagram of a mold (200) of the present invention is shown.

[0178] Figure 6 This is an example of a cross-sectional view of a mold for molding beads foam of the present invention.

[0179] Figure 7A This is a front view of the inner surface of the feeder-side mold of the beads foam molding mold of the present invention.

[0180] Figure 7B This is a front view of the inner surface of the opposing mold of the beads foam molding mold of the present invention.

[0181] Figure 8A This is a perspective view of the feeder side of the beads foam of the present invention.

[0182] Figure 8B It is a perspective view of the opposite side surface of the beads foam of the present invention.

[0183] Figure 9A This is an example of a perspective view of a feeder used in the beads foam molding mold of the present invention as viewed from above the back surface.

[0184] Figure 9B For Figure 9A An example of a stereoscopic view of a feeder viewed from above the front.

[0185] Figure 9C for Figure 9A Example of a top view of a feeder.

[0186] Figure 9D for Figure 9A Example of a side view of a feeder.

[0187] Figure 9E for Figure 9A The following figure shows an example of a feeder.

[0188] Figure 9F for Figure 9A Example of a rear view of a feeder.

[0189] Figure 9G for Figure 9A Example of a front view of a feeder.

[0190] Figure 9H For Figure 9A An example of a stereogram of a feeder viewed from the backside below.

[0191] Figure 9I For Figure 9A An example of a stereoscopic view of a feeder viewed from the front below.

[0192] Figure 10A This is an example of a perspective view of a feeder (having a vent (slit) at the discharge port) used in the beads foam molding die of the present invention, as viewed from above on the back side.

[0193] Figure 10B For Figure 10A An example of a stereoscopic view of a feeder viewed from above the front.

[0194] Figure 10C for Figure 10A Example of a top view of a feeder.

[0195] Figure 10D for Figure 10A Example of a side view of a feeder.

[0196] Figure 10E for Figure 10A The following figure shows an example of a feeder.

[0197] Figure 10F for Figure 10A Example of a rear view of a feeder.

[0198] Figure 10G for Figure 10AExample of a front view of a feeder.

[0199] Figure 10H For Figure 10A An example of a stereogram of a feeder viewed from the backside below.

[0200] Figure 10I For Figure 10A An example of a stereoscopic view of a feeder viewed from the front below.

[0201] Figure 11A This is an example of a top perspective view of a vent plug used in the bead foam molding mold of the present invention.

[0202] Figure 11B for Figure 11A Example of a top view of a vent plug.

[0203] Figure 11C for Figure 11A Example of a side view of a vent plug.

[0204] Figure 11D for Figure 11A The vent plug from Figure 11C Examples of side views from different viewing directions.

[0205] Figure 11E for Figure 11A The following figure shows an example of a vent plug.

[0206] Figure 11F for Figure 11A Example of a perspective view of the underside of a vent plug.

[0207] Figure 12A This is a front view of the inner surface of a feeder-side mold of a bead foam molding mold having a runner portion.

[0208] Figure 12B It is a front view of the inner surface of the opposite side mold of the bead foam molding mold having a runner portion.

[0209] Figure 13A This is a perspective view of the feeder side of the bead foam body having the flow channel portion.

[0210] Figure 13B It is a perspective view of the opposite side of the beads foam body having the flow channel portion.

[0211] Figure 13C This is a diagram showing a state in which the flow channel portion is cut out from a beads foam body having the flow channel portion.

[0212] Figure 14A This is a front side perspective view of the mold used in Example 21.

[0213] Figure 14B This is a perspective view of the back side of the mold used in Example 21.

[0214] Figure 14C A diagram showing the front shape of the mold used in Example 21.

[0215] Figure 14D This is a diagram showing the cross-sectional shape of the mold used in Example 21.

[0216] Figure 15A This is a front side perspective view of the mold used in Example 22.

[0217] Figure 15B This is a perspective view of the back side of the mold used in Example 22.

[0218] Figure 15C This is a diagram showing the front shape of the mold used in Example 22.

[0219] Figure 15D This is a diagram showing the cross-sectional shape of the mold used in Example 22.

[0220] Figure 16A This is a front side perspective view of the mold used in Example 23.

[0221] Figure 16B This is a perspective view of the back side of the mold used in Example 23.

[0222] Figure 16C A diagram showing the front shape of the mold used in Example 23.

[0223] Figure 16D This is a diagram showing the cross-sectional shape of the mold used in Example 23.

[0224] Figure 17A This is a front side perspective view of the mold used in Example 24.

[0225] Figure 17B This is a perspective view of the back side of the mold used in Example 24.

[0226] Figure 17C A diagram showing the front shape of the mold used in Example 24.

[0227] Figure 17D This is a diagram showing the cross-sectional shape of the mold used in Example 24.

[0228] Figure 18A This is a front side perspective view of the mold used in Example 25.

[0229] Figure 18BThis is a back side perspective view of the mold used in Example 25.

[0230] Figure 18C This is a diagram showing the front shape of the mold used in Example 25.

[0231] Figure 18D This is a diagram showing the cross-sectional shape of the mold used in Example 25.

[0232] Figure 19A This is a front side perspective view of the mold used in Example 26.

[0233] Figure 19B This is a perspective view of the back side of the mold used in Example 26.

[0234] Figure 19C A diagram showing the front shape of the mold used in Example 26.

[0235] Figure 19D This is a diagram showing the cross-sectional shape of the mold used in Example 26.

[0236] Figure 20A This is a front side perspective view of the mold used in Example 27.

[0237] Figure 20B This is a back side perspective view of the mold used in Example 27.

[0238] Figure 20C A diagram showing the front shape of the mold used in Example 27.

[0239] Figure 20D This is a diagram showing the cross-sectional shape of the mold used in Example 27.

[0240] Figure 21A This is a front side perspective view of the mold used in Example 28.

[0241] Figure 21B This is a back side perspective view of the mold used in Example 28.

[0242] Figure 21C This is a diagram showing the front shape of the mold used in Example 28.

[0243] Figure 21D This is a diagram showing the cross-sectional shape of the mold used in Example 28.

[0244] Figure 22A This is a front side perspective view of the mold used in Example 29.

[0245] Figure 22B This is a perspective view of the back side of the mold used in Example 29.

[0246] Figure 22C A diagram showing the front shape of the mold used in Example 29.

[0247] Figure 22D This is a diagram showing the cross-sectional shape of the mold used in Example 29.

[0248] Figure 23A This is a front side perspective view of the mold used in Example 30.

[0249] Figure 23B This is a back side perspective view of the mold used in Example 30.

[0250] Figure 23C This is a diagram showing the front shape of the mold used in Example 30.

[0251] Figure 23D This is a diagram showing the cross-sectional shape of the mold used in Example 30.

[0252] Figure 24A This is a front side stereoscopic view of the mold used in Example 31.

[0253] Figure 24B This is a back side perspective view of the mold used in Example 31.

[0254] Figure 24C A diagram showing the front shape of the mold used in Example 31.

[0255] Figure 24D This is a diagram showing the cross-sectional shape of the mold used in Example 31.

[0256] Figure 25A This is a front side stereoscopic view of the mold used in Example 32.

[0257] Figure 25B This is a back side stereoscopic view of the mold used in Example 32.

[0258] Figure 25C A diagram showing the front shape of the mold used in Example 32.

[0259] Figure 25D This is a diagram showing the cross-sectional shape of the mold used in Example 32.

[0260] Figure 26A This is a front side stereoscopic view of the mold used in Example 33.

[0261] Figure 26B This is a back side stereoscopic view of the mold used in Example 33.

[0262] Figure 26CA diagram showing the front shape of the mold used in Example 33.

[0263] Figure 26D This is a diagram showing the cross-sectional shape of the mold used in Example 33.

[0264] Figure 27A This is a front side stereoscopic view of the mold used in Example 34.

[0265] Figure 27B This is a back side stereoscopic view of the mold used in Example 34.

[0266] Figure 27C A diagram showing the front shape of the mold used in Example 34.

[0267] Figure 27D This is a diagram showing the cross-sectional shape of the mold used in Example 34.

[0268] Figure 28A This is a front side stereoscopic view of the mold used in Example 35.

[0269] Figure 28B This is a back side stereoscopic view of the mold used in Example 35.

[0270] Figure 28C A diagram showing the front shape of the mold used in Example 35.

[0271] Figure 28D This is a diagram showing the cross-sectional shape of the mold used in Example 35.

[0272] Figure 29A This is a front perspective view of the mold used in Comparative Examples 5 and 6.

[0273] Figure 29B This is a rear perspective view of the mold used in Comparative Examples 5 and 6.

[0274] Figure 29C 3 is a diagram showing the front shape of the mold used in Comparative Examples 5 and 6.

[0275] Figure 29D 3 is a diagram showing the cross-sectional shape of the mold used in Comparative Examples 5 and 6.

[0276] Figure 30 It is a figure which shows the opening part of the ventilation plug used in Example and comparative example.

[0277] Figure 31 This is a photograph of a bead foam according to the present invention.

[0278] Figure 32 This is a photograph of a bead foam that does not comply with the present invention. DETAILED DESCRIPTION

[0279] (definition)

[0280] The terms used in this specification are defined below.

[0281] <Beads Foam and Parts of Beads Foam>

[0282] <<Bead foam, foam beads>>

[0283] In this specification, "beads foam" refers to a molded body formed by agglomerating expanded beads. In this specification, "expanded beads" are the molding material of beads foam and refer to porous bead-shaped (particle-shaped) objects generated by foaming.

[0284] <<Flow channel part, main body part>>

[0285] In this specification, the term "flow channel portion" refers to the portion of the beads foam that is removed as a waste portion during use. Furthermore, if the beads foam has a flow channel portion, the portion of the beads foam other than the flow channel portion is referred to as the "main body portion."

[0286] <Parts of the Mold>

[0287] <<Molding material fills the space>>

[0288] In this specification, the "molding material filling space" refers to the void space in a mold for filling the molding material (expanded beads) to mold a molded article.

[0289] <<Ventilation plug>>

[0290] In this specification, the "vent plug" refers to a filler of a hole provided on the wall surface of a void space for allowing steam or air to pass through.

[0291] <<Feeder, vent>>

[0292] <Parts of the feeder>

[0293] In this specification, a "feeder" refers to a delivery tube used to introduce expanded beads into the molding material-filled space. The feeder may have a "vent" (e.g., a slit) near the discharge port. A vent (e.g., a slit) is a hole used to allow excess air to escape from the molding material-filled space into the chamber and / or to allow air, vapor, etc. to flow in and out of the molding material-filled space.

[0294] (Contents of the present invention)

[0295] The following describes a part of the present invention in detail with reference to the accompanying drawings. It should be noted that the accompanying drawings are examples for illustrating the present invention, and the technical scope of the present invention is not limited by the examples based on the accompanying drawings.

[0296] (Feeder for bead filling)

[0297] The bead-filled feeder of the present invention has a plunger tube length of 10 mm to 40 mm at the front end and an inclination angle of 10 degrees to less than 30 degrees at the inclined portion of the front end.

[0298] <Structure of feeder>

[0299] Figure 1 An example of a schematic diagram of a feeder (1) of the present invention is shown. Figure 2 An example of a schematic diagram showing the periphery of the front end portion (2) of the feeder (1) of the present invention. Figure 3 An example of a schematic diagram of the feeder (1) of the present invention when in use is shown. It should be noted that, Figure 1 、 Figure 2 In the figure, a schematic diagram of a single-tube nozzle type feeder is shown as an example of the feeder (1) of the present invention, but in the case where the feeder (1) of the present invention is a focus type feeder, the front end portion (2) and the periphery thereof also have the same structure.

[0300] The feeder (1) of the present invention comprises at least a main pipe portion (3) and a front end portion (2) (sometimes also referred to as a "front pipe"). The feeder (1) of the present invention may optionally further comprise a branch pipe (4) branching from the main pipe portion (3), a plunger (5), and a rod (6) connected to the plunger (5).

[0301] The main pipe section (3) is a section including a pipe for carrying the foamed beads in the air flow and transporting them. The front end section (2) is a section that discharges the foamed beads transported from the main pipe section (3) from the discharge port. The front end section (2) has a region (hereinafter referred to as the "inclined section (2a)") in which the flow path is inclined so that the inner diameter continuously decreases from the connection section with the main pipe section (3) toward the discharge port, and a region from the discharge port side end point of the inclined section (2a) to the discharge port (the region where the plunger (5) is arranged when the plunger (5) moves toward the discharge port side. Hereinafter, it is sometimes referred to as the "plunger tube region"). The length from the discharge port side end point of the inclined section (2a) to the discharge port is referred to as the "plunger tube length (L)". In the feeder (1) of the present invention, the extrapolated intersection point of the inclined flow path from the inclined section (2a) is referred to as the "intersection point (2b)". The "intersection point (2b)" is preferably located outside the feeder (1). The distance between the intersection point (2b) and the outlet is called the "intersection distance (D)" of the inclined flow path. The angle between the extrapolated lines of the inclined flow path at the intersection point (2b) in cross-sectional view is called the "inclination angle (θ)" of the inclined flow path.

[0302] The plunger tube length (L) needs to be 10 mm or more and 40 mm or less. When used for producing bead foams as thin-walled molded articles, it is preferably 15 mm or more, preferably 30 mm or less, and more preferably 27 mm or less. By using a feeder (1) having a plunger tube length (L) within the above range in a mold, it is possible to produce bead foams having a perfect shape without defects, particularly bead foams as thin-walled molded articles.

[0303] The inclination angle (θ) of the inclined flow path needs to be 10 degrees or more and less than 30 degrees. When used for the production of bead foam as a thin-walled molded article, it is preferably 15 degrees or more, more preferably 20 degrees or more, and preferably 25 degrees or less. By using a feeder (1) having a plunger tube length (L) within the above range for the mold, a bead foam having a perfect shape without defects, in particular a bead foam as a thin-walled molded article, can be produced.

[0304] The intersection point (2b) of the inclined flow path is preferably located outside the feeder (1). In this case, the intersection distance (D) is preferably 0 mm or more and preferably 20 mm or less. By using the feeder (1) having the intersection distance (D) of the inclined flow path within the above range in the mold, it is possible to produce a bead foam with further reduced defects and a more improved shape, especially a bead foam as a thin-walled molded article.

[0305] The front end portion (2) of the feeder (1) of the present invention may be, for example, Figure 4The front end portion (2) of the feeder (1) is provided with a vent hole (e.g., a slit (2c)). If the front end portion (2) of the feeder (1) is provided with a vent hole (e.g., a slit (2c)), the exhaust of the air supplied to introduce the foamed beads into the mold can be ensured, and the molding of an incomplete bead foam body due to missing filling of the foamed beads near the discharge port of the feeder (1) can be suppressed, especially the molding of the bead foam body as a thin-walled molded product, which is preferred.

[0306] (Mold for molding beads foam)

[0307] In one embodiment, the bead foam molding die (200) of the present invention is, for example, Figure 5 The structure shown may be as follows: the molding material filling space (205) of the mold (200) has a pair of opposing faces, the molding material filling space (205) is connected to one or more feeders (203), one of the pair of faces has a discharge outlet (203a) of the feeder (203) at one or more locations, and one or more of the feeders (203) is the feeder (1) of the present invention. The number of feeders (203) provided by one mold (200) is not particularly limited, and the number of feeders can be appropriately increased as the size of the molded product molded using the mold (200) increases. The bead foam produced using such a mold can be a molded product with small thickness irregularities (flat molded product). The thickness of the thinnest part of the flat molded product can be 5 mm or less, preferably 2 mm or more. By using such a mold, a bead foam with a complete shape without defects, especially a bead foam as a thin-walled molded product, can be produced.

[0308] In another embodiment, the mold (200) for molding beads foam of the present invention may have the following structure: the molding material filling space (205) of the mold (200) has a pair of opposing surfaces, the molding material filling space (205) is connected to two or more feeders (203), one of the pair of surfaces has discharge ports (203a) of the feeders (203) at two or more locations, the thickness of the thinnest portion of the molding material filling space (205) where at least one of the discharge ports (203a) of the feeders (203) is located is 5 mm or less, and the thickness of a portion of the molding material filling space (205) is 60 mm or less, preferably 30 mm or less, preferably 1 mm or more, and more preferably 2 mm or more. By using such a mold, beads foam having portions with different thicknesses, particularly beads foam as a thin-walled molded article, can be manufactured as a beads foam having a perfect shape without defects.

[0309] In any embodiment, a vent (e.g., a slit hole) may be present near at least one of the discharge outlets of the feeder. In addition, a surface (hereinafter referred to as "the other surface") different from the surface (hereinafter referred to as "the one surface") having the discharge outlet (203a) of the feeder (203) at multiple locations may have a breathable plug (204b). In addition, the area where the discharge outlet (203a) of at least one feeder (203) in the one surface exists and the area where at least one breathable plug (204c) in the other surface exists may have an overlapping area when viewed perpendicular to the opposite surface. In this case, the opening portion in the breathable plug and the opening portion of the feeder capable of supplying foamed beads may have an overlapping area when viewed perpendicular to the opposite surface.

[0310] (Bead foam)

[0311] The beads foam of the present invention is a resin-containing beads foam having one or more portions corresponding to feeder discharge marks during bead foam molding. The density of these portions corresponding to the feeder discharge marks during bead foam molding is 110 to 300% of the average density of the entire beads foam molded body. The term "portion corresponding to the feeder discharge mark" herein includes portions corresponding to the feeder discharge mark, portions surrounding the feeder discharge mark, portions bearing marks caused by the feeder, feeder fittings, the feeder mounting portion of the mold, and portions subjected to compression caused by discharge from the feeder. The beads foam of the present invention may have a minimum thickness of 5 mm or less for at least one of the portions corresponding to the feeder discharge mark. Furthermore, in the beads foam of the present invention, the elastic modulus of the portion corresponding to the feeder discharge mark during bead foam molding may be 120 to 600% of the average elastic modulus of the entire beads foam molded body. Furthermore, the beads foam of the present invention may have a vent mark (e.g., a slit mark) around at least one portion of the feeder discharge mark corresponding to the above-mentioned discharge mark during bead foam molding. Such beads foam can be produced, for example, using the beads foam molding mold of the present invention, thereby enabling the production of a beads foam having a flawless, perfectly shaped bead foam, particularly a thin-walled molded article.

[0312] <Material of Bead Foam>

[0313] The beads foam of the present invention comprises a resin as a material. The resin is preferably a thermoplastic resin. Examples of the thermoplastic resin include general-purpose thermoplastic resins such as modified polyphenylene ether (m-PPE), polyamide, polypropylene, polystyrene, high-impact polystyrene, ABS resin, polyethylene (high density, low density), polymethyl methacrylate, polyvinylidene chloride copolymer resin, polyethylene terephthalate, polycarbonate, and mixtures thereof.

[0314] <Shape of Bead Foam>

[0315] The shape of the beads foam (100) of the present invention is not particularly limited. The beads foam (100) of the present invention may have, for example, Figure 8A and 8B The shape of a thin-walled molded product (thin-walled sheet) as shown. The bead foam (100) of the present invention is molded using a mold (200) having a molding material filling space (205) (which has a shape corresponding to the shape of the bead foam (100)). In the present invention, as the mold (200), a mold having a discharge port (203a) of a feeder (203) for supplying foamed beads as a raw material constituting the bead foam (100) and a vent plug (204a, 204b, 204c) on the inner surface of the molding material filling space (205) is usually used. With respect to the mold (200), for example, as described below, Figure 6 、 7A The molding is performed in the molding material filling space (205) of the mold (200) composed of a pair of molds (in the present invention, for convenience, referred to as the feeder side mold (201) and the opposite side mold (202) as shown in 7B. And, if the bead foam (100) of the present invention taken out from the mold (200) after molding has, for example, Figure 8A and 8B For example, a thin-walled molded product (thin-walled sheet) having the shape shown in FIG. 1 has a pair of opposing surfaces (101, 102). For convenience, the sheet surface that contacts the inner surface of the feeder-side mold (201) during molding is referred to as the "feeder-side surface (101)", and the sheet surface that contacts the inner surface of the opposite-side mold (202) during molding is referred to as the "opposite-side surface (102)".

[0316] <Surface State of Bead Foam>

[0317] The feeder-side surface (101) of the bead foam (100) of the present invention has a feeder discharge mark (103) including a portion corresponding to the discharge outlet (203a) of the feeder (203) in the feeder-side mold (201) during bead foam molding (hereinafter sometimes referred to as "feeder discharge outlet equivalent portion", "feeder discharge outlet mark", etc.), and optionally has a vent plug mark (104a) including a portion corresponding to the vent plug (204a) (hereinafter referred to as "vent plug equivalent portion"). The feeder discharge mark (103) may be present in one or more than two forms on the feeder-side surface (101). The feeder discharge mark (103) and the vent plug mark (104a) may also be identified as, for example, a feeder mark and a vent plug mark, respectively. In addition, when the feeder has a vent hole (e.g., a slit hole) near the discharge outlet, the feeder discharge mark (103) can be identified as a vent hole mark (e.g., a slit mark) around the feeder discharge mark (e.g., a portion equivalent to the feeder discharge outlet).

[0318] The opposing surface (102) of the bead foam (100) of the present invention has a portion corresponding to a gas plug (204b) in the opposing mold (202) during bead foam molding (hereinafter referred to as "gas plug corresponding portion (104b)"). The gas plug corresponding portion (104b) can be identified as, for example, a gas plug mark.

[0319] As described below, the bead foam of the present invention is manufactured using a mold in which the area where at least one feeder is present in the feeder-side mold surface and the area where at least one vent plug is present in the opposite mold surface have overlapping areas when viewed perpendicularly to the opposite surface. Specifically, the mold is a mold in which the opening portion in the vent plug and the opening portion (discharge port) for the foamed beads (thermoplastic resin beads) that can be fed to the feeder have overlapping areas when viewed perpendicularly to the opposite surface. Taking this into consideration, the at least one feeder discharge mark (103) in the feeder-side surface (101) of the bead foam (100) of the present invention and the equivalent portion of at least one vent plug in the opposite surface (102) (for example) have overlapping areas. Figure 7B The equivalent portion (104c) of the air permeable plug in the embodiment preferably has an overlapping area when viewed perpendicularly to either the surface (101) on the feeder side or the surface (102) on the opposite side.

[0320] <Thickness of Bead Foam>

[0321] The thickness of the bead foam (100) of the present invention is not particularly limited. For example, the thinnest thickness of the portion corresponding to the feeder discharge mark (103) (for example, the portion corresponding to the feeder discharge outlet) is preferably 5.0 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less. When there are two or more feeder discharge marks (103), at least one feeder discharge mark (103) satisfies the above-mentioned thinnest thickness range, and preferably all feeder discharge marks (103) satisfy the above-mentioned thinnest thickness range. When the thinnest thickness of the portion corresponding to the feeder discharge mark in the bead foam is 5.0 mm or less, filling in the molding process usually becomes difficult, and in particular, the filling performance around the portion corresponding to the feeder discharge mark tends to deteriorate. When filling the thin-walled portion like this, the crack filling method described later is usually used for filling. However, if crack filling is used, although the filling performance can be improved, problems such as deterioration of thickness accuracy, increase in the mold clamping force of the molding machine, and bending of the foam will occur.

[0322] The thickness of a portion of the beads foam of the present invention is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 7 mm or more, and preferably 60 mm or less, and even more preferably 30 mm or less. With such beads foam, it is possible to simultaneously perform filling and molding of beads foam having portions of varying thicknesses, i.e., molded articles having both thin-walled and thick-walled portions. Furthermore, it is possible to simultaneously perform filling and molding of beads foam having a flawless, fully shaped article, particularly, molded articles having both thin-walled and thick-walled portions.

[0323] <State of Expanded Beads in Bead Foam>

[0324] The average particle size of expanded beads in the beads foam at the portion corresponding to the feeder discharge trace (measured on the cross section of the beads foam per 1 cm of the portion corresponding to the feeder discharge trace) 2 The average particle size in the cross section is preferably more than 0.5 mm, more preferably more than 0.7 mm, further preferably more than 1.0 mm, preferably less than 5.0 mm, more preferably less than 3.0 mm, further preferably less than 2.0 mm, and particularly preferably less than 1.8 mm. If the average particle size is small, the fluid resistance of the flow path in which steam and air circulate between the foaming beads in the molding process becomes large, which has a tendency to easily cause deterioration of filling properties and insufficient heating. On the other hand, if the average particle size is too large, filling properties and shapeability tend to deteriorate. It should be noted that, when the particle shape of the foaming beads in the bead foam is deformed, the equivalent circle diameter can also be used as a substitute indicator.

[0325] The flatness of the expanded beads in the beads foam (measured on the cross section of the beads foam, per 1 cm of the portion corresponding to the feeder discharge mark) 2The average value of (maximum in-plane diameter - maximum thickness diameter) / maximum in-plane diameter in a cross section is preferably 0.7 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. It should be noted that a flattening of 0 indicates that the expanded beads are not flattened at all, resulting in a circular cross-section (no flattening). A smaller flattening value (closer to 0) indicates less flattening of the expanded beads (lower flattening), while a larger flattening value (closer to 1.0) indicates greater flattening of the expanded beads (higher flattening). Excessive flattening of the expanded beads significantly reduces the cushioning properties of the foam.

[0326] When the flatness of the expanded beads is large, the amount of cracks during crack filling (described later) in the molding process generally tends to increase, which can easily lead to deterioration of thickness accuracy, increase in the mold clamping force of the molding machine, and warping of the foam. It should be noted that the "in-plane direction" and "thickness direction" refer to the directions corresponding to the "in-plane direction" (i.e., the direction along the surface) and the "thickness direction" (i.e., the direction corresponding to the thickness of the surface) in the bead foam, respectively.

[0327] The number of expanded beads in the thickness direction of the beads foam (per 1 cm of the portion corresponding to the feeder discharge trace measured on the cross section of the beads foam) 2 The average number of expanded beads in the thickness direction of the cross section (the average number of expanded beads in the thickness direction of the cross section) is preferably 1.2 or more, more preferably 2.0 or more, and even more preferably 3.0 or more. The upper limit is not particularly limited, but is preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less. If the number in the thickness direction is too large, the heating efficiency by steam decreases; if it is too small, the strength of the bead foam is insufficient.

[0328] It should be noted that when there are more than two feeder discharge marks (103), it is sufficient as long as at least one feeder discharge mark (103) meets the above-mentioned average particle size, flatness and number range of the foamed beads in the thickness direction. It is preferred that all feeder discharge marks (103) meet the above-mentioned average particle size, flatness and number range of the foamed beads in the thickness direction.

[0329] <Bead Foam with Flow Channel Portion>

[0330] As another embodiment, the beads foam (100) of the present invention can be, for example, Figure 12A and 12BAs shown, the bead foam (100) of the present invention is divided into a main body (111) and a flow channel (112) region. In addition, the feeder discharge trace (103) may be present inside the flow channel (112) or at the boundary between the main body (111) and the flow channel (112). Such a bead foam (100) can be used, for example, as Figure 11A and 11B The bead foam (100) of the present invention is formed by combining a feeder side mold (201) and an opposing side mold (202) as shown in FIG. When the bead foam (100) has a flow channel portion (112), the flow channel portion (112') can be cut off from the bead foam (100) after molding as shown in FIG. 12C, and the remaining main body portion (111') can be used. In addition, when the flow channel portion is cut off and used, even if filling defects occur in the flow channel portion, filling defects do not occur in the main body portion.

[0331] The flow channel portion (112) may exist in a direction perpendicular to the plane of the bead foam (100). Alternatively, the flow channel portion (112) may exist within the plane of the bead foam (100).

[0332] <Foamed Beads>

[0333] The material of the expanded beads is the same as that of the beads foam to be produced, and is a material containing a resin. The resin is preferably a thermoplastic resin, and specific examples thereof include the thermoplastic resins mentioned above.

[0334] The average particle size of the expanded beads is preferably 0.5 mm or greater, more preferably 0.7 mm or greater, even more preferably 1.0 mm or greater, preferably 5.0 mm or less, more preferably 3.0 mm or less, even more preferably 2.0 mm or less, and particularly preferably 1.8 mm or less. If the average particle size is too small, the flow path width of steam and air flowing between the expanded beads during the molding process may become narrow, which may easily lead to deterioration of filling properties and insufficient heating. On the other hand, if the average particle size is too large, there is a tendency for deterioration of filling properties and shaping properties.

[0335] The expandable beads used in the bead foam production method described below can be obtained by including (impregnating) a blowing agent in a base resin composition to cause foaming (this step is referred to as the "bead foaming step"). Specifically, for example, the following method can be used: according to the method described in Example 1 of Japanese Patent Application Laid-Open No. 4-372630, a base resin composition (in pellet form, bead form, etc.) is contained in a pressure-resistant container, the gas in the container is replaced with dry air, and then a blowing agent (gas) is pressurized into the base resin composition to impregnate the blowing agent (gas). The pressure is then released, and the base resin composition pellets are transferred from the pressure container to a foaming furnace. In the foaming furnace, the base resin composition pellets are heated with pressurized steam while a stirring blade is rotated to foam them, thereby producing expandable beads.

[0336] The conditions for impregnating the base resin composition with the blowing agent (gas) according to the above method are not particularly limited. However, to more efficiently impregnate the base resin composition with the blowing agent (gas), the conditions are preferably an impregnation pressure of 0.3 to 30 MPa, an impregnation temperature of -20 to 100°C, and an impregnation time of 10 minutes to 96 hours. Furthermore, to facilitate achieving the desired expansion ratio and optimizing the appearance, the maximum vapor pressure of the pressurized steam within the foaming furnace is preferably 30 to 700 kPa·G.

[0337] The foaming agent is not particularly limited, and commonly used gases can be used.

[0338] Examples thereof include: inorganic gases such as air, carbon dioxide, nitrogen, oxygen, ammonia, hydrogen, argon, helium, and neon; fluorocarbons such as trichlorofluoromethane (R11), dichlorodifluoromethane (R12), chlorodifluoromethane (R22), tetrachlorodifluoroethane (R112), dichlorofluoroethane (R141b), chlorodifluoroethane (R142b), difluoroethane (R152a), HFC-245fa, HFC-236ea, HFC-245ca, and HFC-225ca; saturated hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, and neopentane; Ethers such as methyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methylfuran, tetrahydrofuran, tetrahydropyran; ketones such as dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone, ethyl n-propyl ketone, ethyl n-butyl ketone; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol; carboxylic acid esters such as methyl formate, ethyl formate, propyl formate, butyl formate, amyl formate, methyl propionate, ethyl propionate; chlorinated hydrocarbons such as methyl chloride and ethyl chloride; etc.

[0339] These may be used alone or in combination of two or more.

[0340] From the aspect of flame retardancy, the foaming agent preferably does not have flammability and combustion-supporting property, or has low flammability and combustion-supporting property. From the aspect of gas safety, inorganic gases are more preferred. In addition, inorganic gases are not easily soluble in resins than organic gases such as hydrocarbons. After the foaming process or the molding process, the gas is easily discharged from the resin. Therefore, it also has the advantage of more excellent dimensional stability of the foam after molding over time. Furthermore, when using inorganic gases, it is also not easy to plasticize the resin due to residual gas. It also has the advantage of easily showing excellent heat resistance at an earlier stage without going through processes such as aging. Among inorganic gases, carbon dioxide is preferred from the aspect of solubility in resin and ease of handling. In addition, hydrocarbon-based organic gases are generally highly flammable. When remaining in the foam, the flame retardancy tends to deteriorate.

[0341] (Mold)

[0342] The mold (200) used for molding the bead foam (100) of the present invention can be, for example, Figure 6 、 7A 7B shows the following bead foam molding mold:

[0343] The molding material filling space (205) of the mold (200) has a pair of opposite faces.

[0344] One of the pair of surfaces has a discharge port (203a) of the feeder (203),

[0345] The other side has a breathable plug (204b),

[0346] The thickness of the molding material filling space (205) at the discharge port of the feeder (203) is less than 5 mm,

[0347] The area where the discharge outlet (203a) of at least one feeder (203) in the above-mentioned one side exists and the area where at least one air plug (204c) in the above-mentioned other side exists have an overlapping area when viewed from a perspective perpendicular to the opposite side (the opening portion in the air plug and the opening portion of the foamed beads that can be supplied to the feeder may have an overlapping area when viewed from a perspective perpendicular to the opposite side).

[0348] Figure 6 、 7AAnd 7B shows a mold (200) composed of a feeder side mold (201) and an opposite side mold (202), wherein the above-mentioned "one side" having the discharge port of the feeder (203) exists in the feeder side mold (201), and the above-mentioned "other side" having the air permeable plug (204b) exists in the opposite side mold (202). For convenience, the above-mentioned "one side" and "other side" are respectively referred to as "the mold inner surface of the feeder side mold (201)" and "the mold inner surface of the opposite side mold (202)". The mold inner surface of the feeder side mold (201) can optionally have a air permeable plug (204a). In addition, the area where the discharge outlet of at least one feeder (203) exists on the inner surface of the mold of the feeder side mold (201) and the area where at least one air plug (204c) exists on the inner surface of the mold of the opposite side mold (202) can have an overlapping area when viewed from a perspective perpendicular to the opposite surfaces, thereby enabling the molding of the bead foam (100) as a thin-walled molded product (thin-wall sheet).

[0349] <Feeder>

[0350] The feeder (203) is a conveying pipe for introducing the foaming beads (150) into the molding material filling space (205). There can be one or more feeders (203). In addition, there can be one or more discharge outlets (203a) of the feeder (203) on the inner surface of the mold (201) on the feeder side. The shape of the front end (discharge outlet) on the molding material filling space side of the feeder (203) is not particularly limited. At least one of the discharge outlets (203a) of the feeder (203) can be, for example, Figure 9A The shape of the tube tip without modification as shown can also be Figure 9B The shape of the front end of the tube having a vent hole (e.g., a slit (206)) as shown. If a vent hole (e.g., a slit (206)) is provided at the front end (discharge port (203a)) of the feeder (203) on the side of the molding material filling space, the discharge of the air introduced into the foam beads (150) can be ensured, and the formation of an incomplete thin-walled molded product due to the lack of filling of the foam beads (150) near the feeder (203) can be suppressed, which is preferred.

[0351] <Breathable plug>

[0352] The filler used as the vent plugs (204a, 204b, 204c) (hereinafter also collectively referred to as "vent plugs (204)") is not particularly limited, and examples thereof include fillers having a shape as shown in FIG. 10.

[0353] Regarding the ventilation plug (204) arranged at a portion having an overlapping area with the discharge port of the feeder in a vertical viewing angle relative to the opposite surface, the total opening area (mm) of the portion that can actually pass steam, air, etc. 2 ) For example, preferably 1mm 2 More than 5mm, more preferably 2 More preferably, 9mm 2 Above, preferably 300mm 2 Less than, more preferably 200mm 2 Below, more preferably 180mm 2 the following.

[0354] The size of the air permeable plug (204) arranged at a portion having an overlapping area with the area where the discharge outlet of the feeder exists at a viewing angle perpendicular to the opposite surface (the diameter of the peripheral portion through which air and steam pass) is, for example, preferably greater than 2 mm, more preferably greater than 3 mm, further preferably greater than 5 mm, preferably less than 30 mm, more preferably less than 15 mm, further preferably less than 20 mm.

[0355] The slit width of the vent plug (204) disposed at a portion having an overlapping region with the region where the discharge port of the feeder exists in a vertical viewing angle relative to the opposing surface is preferably 0.05 mm or more, more preferably 0.10 mm or more, and even more preferably 0.15 mm or more. In addition, it is preferably 2.0 mm or less, more preferably 1.5 mm or less, and even more preferably 1.0 mm or less. If the opening area, diameter, and slit width are within the above ranges, it is preferred from the perspectives of being able to effectively form a flow path for air introduced from the feeder during filling, facilitating heating of the expanded beads present in the vicinity of the feeder during the heating process, and preventing traces of the vent plug remaining in the bead foam after molding from becoming noticeable.

[0356] In addition, at the location where the vent plug (204) is arranged at the overlapped area with the discharge port of the feeder in the vertical viewing angle relative to the opposite surface, the total opening area (mm 2 ) / The circumference of the outer periphery of the vent plug opening (mm) can be used as an indicator of the relative width of the flow path where air and steam actually flow. If the opening area is the same, the total opening area (mm 2 ) / The larger the circumference of the opening (mm), the wider the flow path, which reduces the fluid resistance, so that air and steam can flow efficiently. The total opening area (mm 2 ) / perimeter of the opening (mm) is preferably 0.01 or more, more preferably 0.09 or more, and further preferably 0.19 or more.

[0357] From the same perspective as above, the sum of the overlapping areas of the opening of the vent plug (204) and the opening of the discharge outlet of the feeder, the perimeter of the overlapping area, and the sum of the overlapping areas / the perimeter of the overlapping area, which overlap with the area where the discharge outlet of the feeder exists when viewed perpendicularly to the opposite surface, can be defined. The sum of the overlapping areas, the perimeter of the overlapping area, and the sum of the overlapping areas / the perimeter of the overlapping area are particularly important because they relate to the area that functions as a flow path for air to flow when the expanded beads are filled.

[0358] The sum of the overlapping areas of the opening of the vent plug (204) and the opening of the discharge outlet of the feeder arranged at the portion having the overlapping area at a viewing angle perpendicular to the opposite surface is preferably 1 mm. 2 More than 5mm, more preferably 2 More preferably, 9mm 2 Above, preferably 300mm 2 Less than, more preferably 200mm 2 Below, more preferably 180mm 2 the following.

[0359] The size of the overlapping portion (the diameter of the outer periphery of the portion through which air and steam flow) of the opening portion of the air permeable plug (204) arranged at a portion having an overlapping region with the region where the discharge outlet of the feeder exists at a viewing angle perpendicular to the opposite surface and the overlapping portion of the opening portion of the discharge outlet of the feeder is, for example, preferably greater than 2 mm, more preferably greater than 3 mm, further preferably greater than 5 mm, preferably less than 30 mm, more preferably less than 15 mm, further preferably less than 20 mm.

[0360] In addition, the sum of the overlapping areas (mm) of the opening of the vent plug (204) and the opening of the feeder outlet arranged at the portion having the overlapping area in the area where the feeder outlet exists at a viewing angle perpendicular to the opposite surface is 2 ) / perimeter of the repeating part (mm) can be used as an indicator of the relative width of the flow path where air and steam actually flow. If the repeating area is the same, the sum of the repeating areas (mm 2 ) / The larger the perimeter of the repeating part (mm), the wider the flow path is, and the fluid resistance is reduced, so air and steam can flow efficiently. The total repeating area (mm 2 ) / repeating portion perimeter (mm) is preferably 0.01 or more, more preferably 0.09 or more, and further preferably 0.19 or more.

[0361] <Thickness of the Molding Material Filling Space>

[0362] The thickness of the molding material filling space (205) is set corresponding to the thickness of the molded bead foam (100), and the thickness of the molding material filling space (205) at the discharge port of the feeder (203) is 5 mm or less, preferably 4.5 mm or less, and more preferably 4.0 mm or less. When the thickness of the molding material filling space (205) at the discharge port of the feeder (203) is 5 mm or less, filling in the molding process usually becomes difficult, especially the filling property around a considerable part of the feeder discharge port tends to deteriorate. When filling a thin-walled part like this, the crack filling method described later is usually used for filling. However, if the crack filling method is used, although the filling property can be improved, problems such as deterioration of thickness accuracy, increase in the mold clamping force of the molding machine, and bending of the foam body will occur.

[0363] <Mold with runner area>

[0364] As another embodiment, for example, Figure 12A and 12B In the case of molding a bead foam (100) having a flow channel portion (112) as shown, the molding material filling space (205) of the mold (200) may have a portion (flow channel region (212a, 212b)) corresponding to the flow channel portion (112). In this case, the flow channel region (212a) in the mold inner surface of the feeder side mold (201) has a discharge port (203a) of the feeder (203). In addition, the thickness of the molding material filling space (205) at the interface portion between the portion 112 where the discharge port (203a) of the feeder (203) exists and the main body portion 111 is preferably 5 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less. It should be noted that in the molding material filling space (205), the portion other than the flow channel region (212a, 212b) becomes the main body region (211a, 211b).

[0365] (Method for producing beads foam)

[0366] The beads foam of the present invention can be produced, for example, by the following production method (hereinafter referred to as "the production method of the present invention").

[0367] A method for producing a bead foam comprises the following steps:

[0368] A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and

[0369] The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body.

[0370] The molding material filling space of the above-mentioned mold has a pair of opposite surfaces.

[0371] One of the pair of surfaces has a discharge port of the feeder at one or more locations.

[0372] The intersection point of the air flow path of the feeder exists in the molding material filling space.

[0373] The beads foam of the present invention can also be produced by an in-mold foaming method.

[0374] In this case, the method for forming a foamed article using the expandable beads is not particularly limited, and an example thereof includes a method in which the expandable beads are filled into a space filled with a molding material, the expandable beads are heated to fuse the expandable beads together, and the product is solidified by cooling to form the article (this process is also referred to as an in-mold foaming method). The method for filling the expandable beads is not particularly limited, and a known method can be used.

[0375] In the in-mold foaming method, a mold of the desired shape is prepared and filled with expandable beads for molding. This makes it easy to mold the foam into finer and more complex shapes. Furthermore, the in-mold foaming method easily increases the expansion ratio of the foam, and the resulting foam tends to exhibit both thermal insulation properties and flexibility.

[0376] In the production method of the present invention, the feeder of the present invention described above can be used as at least one of the feeders. Furthermore, the mold of the present invention described above can be used as the mold.

[0377] The production method of the present invention is a method for producing a bead foam by an in-mold foaming method. In the in-mold foaming method, a mold of the desired shape is prepared and filled with expandable beads to form the foam. This makes it easy to mold the foam into finer and more complex shapes. Furthermore, the in-mold foaming method easily increases the expansion ratio of the foam, and the resulting foam easily exhibits flexibility in addition to thermal insulation properties.

[0378] Before the foaming beads are filled into the molding material filling space, the foaming beads can be subjected to a gas-based pressure treatment. By applying a certain gas pressure to the bubbles of the foaming beads, the foaming beads expand during the heating process, and the foaming beads constituting the resulting foam body are firmly welded to each other, which can improve the rigidity and appearance of the molded body. The gas used in the pressure treatment is not particularly limited, and air and inorganic gases are preferred from the perspectives of ease of handling and economy. The method for the pressure treatment is not particularly limited, and the following methods can be cited: the foaming beads are filled in a pressurized container, and then pressurized gas is introduced, and the pressure is increased to a maximum pressure of 0.1 to 20 MPa over 10 minutes to 96 hours, thereby supplying the gas to the pressurized container.

[0379] From the perspective of improving lightness, the expansion ratio of the beads foam is preferably 1.5 cm 3 / g or more, more preferably 2.0cm 3 / g or more, more preferably 2.5cm 3 In addition, from the perspective of improving mechanical strength and flame retardancy, the expansion ratio of the beads foam is preferably 100 cm 3 / g or less, more preferably 50cm 3 / g or less, more preferably 30cm 3 / g or less.

[0380] Examples of methods for filling expanded beads include the following: the slit method, which involves filling with the mold slightly open; the compression method, which involves applying pressure while keeping the mold closed to fill compressed beads; and the compression slit method, which involves filling compressed beads and then slitting them. The slit method is often used for filling applications with poor filling performance, as it improves filling performance without requiring special mold adjustments and minimizes cycle time degradation. However, due to factors such as insufficient mold clamping force when closing the mold after slit filling for large product areas, decreased thickness accuracy of the bead foam in the mold clamping direction, and increased density of the bead foam relative to the bulk density of the expanded beads themselves, the slit ratio (described below) is preferably 200% or less, more preferably 100% or less, and even more preferably 50% or less.

[0381] The crack rate is preferably 0% (a method of filling expanded beads in a completely closed mold state without filling by the crack method). In particular, when the thickness of the molding material filling space is 10 mm or less, especially 5 mm or less, the filling property tends to deteriorate significantly.

[0382] Crack rate (%) = (thickness of the space filled by the molding material (mm) + crack amount (mm)) / thickness of the space filled by the molding material (mm) × 100

[0383] ※Gap: The distance the mold is opened during filling (mm)

[0384] It should be noted that the pressure of the filling air during filling is preferably 0.1 MPaG or higher, more preferably 0.2 MPaG or higher, and even more preferably 0.3 MPaG or higher. Furthermore, it is preferably 1.0 MPaG or lower, more preferably 0.8 MPaG or lower, and even more preferably 0.6 MPaG or lower. The filling air pressure within the above range is preferred because it is less likely to cause filling defects due to air interference during filling and because it facilitates the transport of the beads foam.

[0385] The filling time (the time required for the step of filling the expanded beads) is preferably 1 second or longer, more preferably 2 seconds or longer, and even more preferably 3 seconds or longer. Furthermore, it is preferably 20 seconds or shorter, more preferably 15 seconds or shorter, and even more preferably 10 seconds or shorter. A filling time within this range is preferred from the perspectives of lessening cycle time degradation and facilitating the filling of the expanded beads into the molding material filling space within the mold.

[0386] The heating method for molding the expanded beads includes heating using a heat medium such as steam, heating using a heater such as an IR heater, heating using microwaves, etc. When heating using a heat medium, a general heat medium can be used, but steam is preferred from the perspective of efficiently heating the resin.

[0387] The molding method of bead foam using water vapor (steam foam molding) can generally include the following steps: using a mold with a breathable plug, a process called one-side / opposite-side heating to replace the air in the mold and between the foamed beads with steam; a process called two-side heating to introduce steam from both sides of the mold to fully heat the foamed beads and fuse the foamed beads to each other; a cooling process of blowing water to cool the product after heating.

[0388] If the heating temperature of the foaming beads is high, the foaming beads are easily welded to each other, which easily reduces the residual stress of the bead foam, and thus has a tendency to improve formability, the appearance of the molded product, and the heat resistance. However, if the heating temperature is too high, there is a tendency to easily produce shrinkage, warping, etc. of the bead foam. In addition, if the heating time of the foaming beads is long, the foaming beads are easily welded to each other, which easily reduces the residual stress of the bead foam, and thus has a tendency to improve formability and heat resistance. However, if the heating time is too long, shrinkage, warping, etc. of the bead foam, or cycle degradation and formability degradation may occur.

[0389] From the above-mentioned viewpoints, the heating temperature of the expanded beads in the molding step is preferably 50 to 200°C, more preferably 70 to 160°C, and even more preferably 80 to 150°C.

[0390] <Method for producing a bead foam having a flow channel portion>

[0391] The beads foam having a flow channel portion can be produced by the above-mentioned in-mold foaming method, and the beads foam having a desired shape can be obtained by cutting off the flow channel portion after molding.

[0392] Example

[0393] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that the measurement and evaluation methods used in the examples and comparative examples are as follows.

[0394] [Measurement method of thinnest part]

[0395] In a portion corresponding to a discharge trace of a feeder during molding of the beads foam, the thickness of the thinnest portion of the beads foam in a direction perpendicular to the plane of the beads foam was measured.

[0396] In addition, when there are two or more feeders, the thinnest part corresponding to the feeder discharge mark is selected and cut, and the thinnest thickness of this part is used as the thickness of the thinnest part.

[0397] [Expansion ratio of foam]

[0398] Refer to the production method of each foam body and make a sample with a size of 30 mm square and 10 mm thickness. Measure the mass W (g) of the sample and the volume V (cm 3 ) divided by the mass W to obtain the value V / W as the expansion ratio (cm 3 / g).

[0399] [Aperture of Expanded Beads in Bead Foam]

[0400] The flatness of the expanded beads in the beads foam was calculated immediately below the portion corresponding to the feeder discharge mark (per 1 cm of the portion corresponding to the feeder discharge mark measured on the cross section of the beads foam). 2 The average value of (maximum value of in-plane diameter - maximum value of thickness diameter) / maximum value of in-plane diameter) in the cross section).

[0401] It should be noted that regarding the shape of the expanded beads in the bead foam, the bead foam was cut in a direction perpendicular to the plane of the bead foam, and the cross section was observed using a microscope (3D Real Surface View microscope VE-9800 manufactured by Keyence Corporation). The cross-sectional shape of the expanded beads in the cross-sectional image thus obtained was analyzed. Based on the cross-sectional image obtained, the maximum value in the in-plane direction and the maximum value in the thickness direction of each expanded bead observed in the cross section of the bead foam were measured, and the above-mentioned flatness was calculated. This operation was repeated until the total cross-sectional area observed by the same operation reached 1 cm 2 So far, calculate every 1cm 2 The flatness of the expanded beads.

[0402] [Number of expanded beads in the thickness direction of the beads foam]

[0403] The number of expanded beads in the thickness direction of the beads foam was calculated immediately below the portion corresponding to the feeder discharge mark (per 1 cm of the portion corresponding to the feeder discharge mark measured on the cross section of the beads foam). 2 The average number of expanded beads in the thickness direction of the cross section).

[0404] It should be noted that the shape of the expanded beads in the bead foam was analyzed by cutting the bead foam in a direction perpendicular to the plane of the bead foam and observing the cross section using a microscope (3D Real Surface View microscope VE-9800 manufactured by Keyence Corporation). The cross-sectional shape of the expanded beads in the cross-sectional image thus obtained was analyzed. A line (measurement line) was drawn along the thickness direction of the obtained cross-sectional image, and the number of expanded beads contained in the line was measured. This operation was repeated until the total cross-sectional area observed by the operation reached 1 cm. 2 The average number of expanded beads in the thickness direction of the beads foam is calculated until the number of measurement lines is 30 or more. It should be noted that the spacing between the measurement lines is made as uniform as possible so that the number of expanded beads in the thickness direction on each measurement line does not become random.

[0405] [Filling performance of the portion immediately below the feeder outlet]

[0406] In Examples 1 to 19 and Comparative Examples 1 to 4, the filling properties of the obtained beads foams at the portion immediately below the portion corresponding to the feeder discharge mark were evaluated as follows.

[0407] The area of ​​the portion where filling failure occurs (a state where expanded beads are not filled and a defect occurs) when viewed from a direction perpendicular to the surface of the molded body,

[0408] Fill the missing area to 0mm 2 Case: S (no missing padding)

[0409] Fill missing area greater than 0mm 2 and 5mm 2 The following cases: A (almost no filling missing, no practical problems)

[0410] Filling missing area greater than 5mm 2 and 10mm 2 The following situation: B (slightly missing filling, but no practical problem)

[0411] Filling missing area greater than 10mm 2 and 20mm 2 The following situation: C (a small amount of padding is missing, but it is not a practical problem)

[0412] Filling missing area greater than 20mm 2 And 30mm 2 The following situations: D (fill missing)

[0413] Filling missing area greater than 30mm 2 Case: E (obvious lack of padding)

[0414] In Examples 20 to 34 and Comparative Examples 5 to 6, the filling properties of the obtained beads foams at the portion immediately below the portion corresponding to the feeder discharge mark were evaluated as follows.

[0415] The area of ​​the portion where filling failure occurs (a state where expanded beads are not filled and a defect occurs) when viewed from a direction perpendicular to the surface of the molded body,

[0416] Fill the missing area to 0mm 2 Case: +++ (no missing fill)

[0417] Fill missing area greater than 0mm 2 And 30mm 2 The following situation: ++ (slightly missing padding, but no practical problem)

[0418] Filling missing area greater than 30mm 2 And 100mm 2 The following cases: + (fill missing)

[0419] Greater than 100mm 2 Situation: NG (large filling missing)

[0420] Example 1:

[0421] 60% by mass of a polyphenylene ether resin ("S201A" manufactured by Asahi Kasei Corporation), 15% by mass of bisphenol A-bis(diphenyl phosphate) (BBP) (melting point below 20°C) as a non-halogen flame retardant, 10% by mass of an impact-resistant polystyrene resin (HIPS) having a rubber concentration of 6% by mass, and 15% by mass of GP685 (manufactured by PS Japan Co., Ltd.) as a general-purpose polystyrene resin (PS) were added, heated and melt-kneaded in an extruder, and then extruded to produce base resin composition pellets.

[0422] According to the method described in Example 1 of Japanese Patent Application Laid-Open No. 4-372630, base resin composition pellets were placed in a pressure vessel. After the atmosphere in the vessel was replaced with dry air, carbon dioxide (gas) was injected as a blowing agent. The carbon dioxide was allowed to permeate the base resin composition pellets under conditions of 3.0 MPa and 10°C for 3 hours. The pellets were then removed from the pressure vessel and immediately conveyed to a foaming furnace. The pellets were foamed with pressurized steam at a maximum pressure of 330 kPa·G while a stirring blade was rotated at 77 rpm, thereby producing expanded beads having an average particle size of 1.8 mm. The hydrocarbon gas content of the expanded beads was measured by gas chromatography immediately after foaming and was found to be below the detection limit (0.01 mass %).

[0423] The expanded beads were then placed in a container and pressurized air was introduced (the pressure was raised to 0.4 MPa over 4 hours and then maintained at 0.4 MPa for 16 hours) to perform a pressure treatment. Figure 5 In a 150mm×150mm mold of a feeder of the structure shown (filling conditions: filling pressure 0.5MPaG, filling time 5 seconds, crack rate 10%), the foaming beads are heated by water vapor to expand and fuse with each other, then cooled and taken out from the molding mold to obtain a bead foam. In the feeder, the outer diameter of the feeder is Φ28mm, the plunger diameter is Φ10mm, and the inclination angle, plunger tube length and intersection distance (negative indicates that the intersection exists on the inside of the feeder) are shown in Table 1. There is no slit in the front end of the feeder. The crack rate during molding is 10%. The thickness of the foam is 3mm over the entire surface, and the density of the portion corresponding to the feeder discharge mark is about 200% relative to the average density of the entire foam. The evaluation results of the filling property of the foam are shown in Table 1.

[0424] Examples 2 to 17, Comparative Examples 1 to 4:

[0425] Bead foams were produced and evaluated in the same manner as in Example 1, except that the feeder inclination angle, plunger tube length, intersection distance, and presence or absence of a slit in the feeder tip were changed as shown in Table 1. The foam thickness and the density ratio of the portion corresponding to the feeder discharge mark were approximately the same as in Example 1.

[0426] Example 18:

[0427] 60% by mass of a polyphenylene ether resin ("S201A" manufactured by Asahi Kasei Corporation), 15% by mass of bisphenol A-bis(diphenyl phosphate) (BBP) (melting point below 20°C) as a non-halogen flame retardant, 10% by mass of an impact-resistant polystyrene resin (HIPS) having a rubber concentration of 6% by mass, and 15% by mass of GP685 (manufactured by PS Japan Co., Ltd.) as a general-purpose polystyrene resin (PS) were added, heated and melt-kneaded in an extruder, and then extruded to produce base resin composition pellets.

[0428] According to the method described in Example 1 of Japanese Patent Application Laid-Open No. 4-372630, base resin composition pellets were placed in a pressure vessel. After the atmosphere in the vessel was replaced with dry air, carbon dioxide (gas) was injected as a blowing agent. The carbon dioxide was allowed to permeate the base resin composition pellets under conditions of 3.0 MPa and 10°C for 3 hours. The pellets were then removed from the pressure vessel and immediately conveyed to a foaming furnace. The pellets were foamed with pressurized steam at a maximum pressure of 330 kPa·G while a stirring blade was rotated at 77 rpm, thereby producing expanded beads having an average particle size of 1.8 mm. The hydrocarbon gas content of the expanded beads was measured by gas chromatography immediately after foaming and was found to be below the detection limit (0.01 mass %).

[0429] The expanded beads were then placed in a container and pressurized air was introduced (the pressure was raised to 0.4 MPa over 4 hours and then maintained at 0.4 MPa for 16 hours) to perform a pressure treatment. Figure 5In a 700mm×500mm mold of 9 feeders of the structure shown (filling conditions: filling pressure 0.5MPaG, filling time 5 seconds, crack rate 10%), the foamed beads are heated by water vapor to expand and fuse with each other, and then cooled and taken out from the molding mold to obtain a bead foam. In the feeder, the outer diameter of the feeder is Φ28mm, the plunger diameter is Φ10mm, and the inclination angle, plunger tube length and intersection distance (negative indicates that the intersection exists on the inside of the feeder) are shown in Table 1. There is no slit in the front end of the feeder. The crack rate during molding is 10%. The thickness of the foam is 3mm over the entire surface, and the ratio of the density of the portion corresponding to the feeder discharge mark to the average density of the entire foam is about 200%. The evaluation results of the filling property of the foam are shown in Table 1. It shows that even when multiple feeders are configured, uniform filling is performed except for the portion corresponding to the feeder discharge mark.

[0430] Example 19:

[0431] 60% by mass of a polyphenylene ether resin ("S201A" manufactured by Asahi Kasei Corporation), 15% by mass of bisphenol A-bis(diphenyl phosphate) (BBP) (melting point below 20°C) as a non-halogen flame retardant, 10% by mass of an impact-resistant polystyrene resin (HIPS) having a rubber concentration of 6% by mass, and 15% by mass of GP685 (manufactured by PS Japan Co., Ltd.) as a general-purpose polystyrene resin (PS) were added, heated and melt-kneaded in an extruder, and then extruded to produce base resin composition pellets.

[0432] According to the method described in Example 1 of Japanese Patent Application Laid-Open No. 4-372630, base resin composition pellets were placed in a pressure vessel. After the atmosphere in the vessel was replaced with dry air, carbon dioxide (gas) was injected as a blowing agent. The carbon dioxide was allowed to permeate the base resin composition pellets under conditions of 3.0 MPa and 10°C for 3 hours. The pellets were then removed from the pressure vessel and immediately conveyed to a foaming furnace. The pellets were foamed with pressurized steam at a maximum pressure of 330 kPa·G while a stirring blade was rotated at 77 rpm, thereby producing expanded beads having an average particle size of 1.8 mm. The hydrocarbon gas content of the expanded beads was measured by gas chromatography immediately after foaming and was found to be below the detection limit (0.01 mass %).

[0433] The expanded beads were then placed in a container and pressurized air was introduced (the pressure was raised to 0.4 MPa over 4 hours and then maintained at 0.4 MPa for 16 hours) to perform a pressure treatment. Figure 5In a 700mm×500mm mold of 9 feeders of the structure shown (filling conditions: filling pressure 0.5MPaG, filling time 5 seconds, crack rate 10%), the foaming beads are heated by water vapor to expand and fuse with each other, and then cooled and taken out from the molding mold to obtain a bead foam. In the feeder, the outer diameter of the feeder is Φ28mm, the plunger diameter is Φ10mm, and the inclination angle, plunger tube length and intersection distance (negative indicates that the intersection exists on the inside of the feeder) are shown in Table 1. There is a slit at the front end of the feeder. The crack rate during molding is 10%. The thickness of the foam is 3mm over the entire surface, and the ratio of the density of the portion corresponding to the feeder discharge mark to the average density of the entire foam is about 200%. The evaluation results of the filling property of the foam are shown in Table 1. It shows that even when multiple feeders are configured, uniform filling is performed except for the portion corresponding to the feeder discharge mark.

[0434]

[0435] Example 20:

[0436] 60% by mass of a polyphenylene ether resin ("S201A" manufactured by Asahi Kasei Corporation), 15% by mass of bisphenol A-bis(diphenyl phosphate) (BBP) (melting point below 20°C) as a non-halogen flame retardant, 10% by mass of an impact-resistant polystyrene resin (HIPS) having a rubber concentration of 6% by mass, and 15% by mass of GP685 (manufactured by PS Japan Co., Ltd.) as a general-purpose polystyrene resin (PS) were added, heated and melt-kneaded in an extruder, and then extruded to produce base resin composition pellets.

[0437] According to the method described in Example 1 of Japanese Patent Application Laid-Open No. 4-372630, base resin composition pellets were placed in a pressure vessel. After the atmosphere in the vessel was replaced with dry air, carbon dioxide (gas) was injected as a blowing agent. The carbon dioxide was allowed to permeate the base resin composition pellets under conditions of 3.0 MPa and 10°C for 3 hours. The pellets were then removed from the pressure vessel and immediately conveyed to a foaming furnace. The pellets were foamed with pressurized steam at a maximum pressure of 330 kPa·G while a stirring blade was rotated at 77 rpm, thereby producing expanded beads having an average particle size of 1.8 mm. The hydrocarbon gas content of the expanded beads was measured by gas chromatography immediately after foaming and was found to be below the detection limit (0.01 mass %).

[0438] Thereafter, the foamed beads are placed in a container, and pressurized air is introduced (the pressure is increased to 0.4 MPa in 4 hours, and then maintained at 0.4 MPa for 16 hours) to perform a pressurization treatment. The beads are filled into the molding die shown in Figures 14 to 29 (filling conditions: filling pressure 0.4 MPaG, filling time 5 seconds, crack rate 0%), and heated with water vapor to expand and fuse the foamed beads to each other. The beads are then cooled and taken out from the molding die to obtain a bead foam. In the molding die shown in Figures 14 to 23 and Figures 27 and 28, a vent plug is provided on the surface opposite to the discharge port of the feeder during molding of the bead foam. The shape of the opening of the vent plug is shown in FIG. Figure 30 Table 2 shows an overview of mold design, molding process conditions (crack ratio), and foam evaluation results.

[0439] Examples 21 to 34, Comparative Examples 5 to 6:

[0440] Bead foams were produced and evaluated in the same manner as in Example 20 except that the outline of the mold design and the conditions of the molding step (crack ratio) were changed as described in Table 2.

[0441]

[0442]

[0443] Industrial Applicability

[0444] According to the present invention, in the production of beads foam, particularly thin-walled molded articles, beads foam having a flawless, perfect shape can be produced. In particular, the thin-walled molded articles produced in this manner are suitable for use in automotive applications, wireless communications, and the like.

[0445] Explanation of symbols

[0446] 1. Feeder of the present invention

[0447] 1a The discharge port of the feeder of the present invention

[0448] 2Front end (front tube)

[0449] 2a inclined portion

[0450] 2b intersection

[0451] 2c vent (slit)

[0452] 3 Supervisor part

[0453] 4 branch pipes

[0454] 5 plunger

[0455] 6 strokes

[0456] 100 beads foam

[0457] 101 Feeder side surface

[0458] 102 opposite side surface

[0459] 103 Feeder discharge traces

[0460] 104a Vent plug traces (inside the feeder side)

[0461] 104b Ventilation plug mark (on the inside of the opposite side)

[0462] 104c Vent plug mark (located at the feeder discharge mark on the opposite side of the surface)

[0463] 111 Main part

[0464] 111'The main body after being cut off

[0465] 112 runner part

[0466] 112' flow channel after cutting off

[0467] 200 molds

[0468] 201 feeder side mold

[0469] 202 Opposite side mold

[0470] 203 feeder

[0471] 203a Discharge outlet of feeder

[0472] 204 vent plug

[0473] 204a Ventilation plug (inside the mold on the feeder side)

[0474] 204b Ventilation plug (inside the opposite mold)

[0475] 204c Ventilation plug (located at the feeder equivalent in the opposite mold)

[0476] 205 molding material fills the space

[0477] 211a Main body area (inside the feeder side mold)

[0478] 211b Main body area (inside the opposite mold)

[0479] 212a Runner area (inside the mold on the feeder side)

[0480] 212b Runner area (inside the opposite mold)

[0481] L plunger tube length

[0482] D Intersection distance

[0483] θ tilt angle

Claims

1. A feeder for bead filling, wherein: The length of the plunger tube at the front end of the feeder is not less than 10 mm and not more than 40 mm. The inclined flow path of the front end portion of the feeder has an inclination angle of 10 degrees or more and less than 30 degrees.

2. The bead filling feeder according to claim 1, wherein The intersection distance of the inclined flow path at the front end portion of the feeder is not less than 0 mm and not more than 20 mm.

3. The bead filling feeder according to claim 1 or 2, wherein: The front end portion of the feeder has a slit.

4. A bead foam comprising a resin, wherein: The bead foam body has one or more portions corresponding to discharge marks of a feeder during molding of the bead foam body. The thinnest thickness of the portion corresponding to the feeder discharge mark is 5 mm or less.

5. The beads foam according to claim 4, wherein The thickness of a portion of the beads foam is 60 mm or less.

6. The beads foam according to claim 4 or 5, wherein The bead foam body has a pair of opposite surfaces. One of the pair of surfaces has a portion corresponding to a discharge trace of a feeder during molding of the bead foam. The other side has a portion corresponding to the trace of the air plug when the beads are formed. In a viewing angle perpendicular to the one surface, part or all of a portion corresponding to at least one vent plug mark on the other surface exists within the region occupied by the feeder discharge mark.

7. The beads foam according to claim 4 or 5, wherein The bead foam body has a flow channel portion that is cut off during use. The flow channel portion includes a portion corresponding to a discharge trace of a feeder during molding of a beads foam.

8. The bead foam according to claim 7, characterized in that (A) or (B) below: (A) the flow channel portion exists in a direction perpendicular to the plane of the beads foam body; (B) The flow channel portion exists within the plane of the beads foam body.

9. The beads foam according to claim 4 or 5, wherein There are vent hole marks on the feeder discharge mark during bead foam molding.

10. The beads foam according to claim 4 or 5, wherein The flatness of the expanded beads in the portion corresponding to the feeder discharge mark during bead foam molding is 0.7 or less, and the flatness is the square root of the feeder discharge mark corresponding portion per 1 cm measured on the cross section of the expanded beads. 2 The average value of (maximum value of in-plane diameter - maximum value of thickness direction diameter) / maximum value of in-plane diameter) in the cross section.

11. The beads foam according to claim 4 or 5, wherein The number of expanded beads in the bead foam in the thickness direction of the portion corresponding to the feeder discharge mark is 1.2 or more and 15 or less, and the number in the thickness direction is per 1 cm of the portion corresponding to the feeder discharge mark measured on the cross section of the bead foam. 2 The average number of expanded beads in the thickness direction of a cross section.

12. The beads foam according to claim 4 or 5, wherein The ratio of the density of the portion corresponding to the feeder discharge port trace during molding of the beads foamed article to the average density of the entire beads foamed article is 110% to 300%.

13. The beads foam according to claim 4 or 5, wherein The ratio of the elastic modulus of the portion corresponding to the feeder discharge port trace during molding of the beads foamed body to the average elastic modulus of the entire beads foamed body is 120% to 600%.

14. A mold for bead foaming, characterized in that (A) or (B) below: (A) The molding material filling space of the mold has a pair of opposing surfaces, The molding material filling space is connected to the feeder, One of the pair of surfaces has a discharge port of the feeder, The other side has a breathable plug. The thickness of the molding material filling space at the discharge port of the feeder is 5 mm or less. In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface is within the area occupied by the discharge port of the feeder; (B) The molding material-filled space of the mold has a portion corresponding to the runner portion of the beads foam molded by the mold that is cut away during use. The portion corresponding to the flow channel has a feeder discharge mark, The thickness of the molding material-filled space at the portion where the discharge port of the feeder exists is 5 mm or less.

15. A mold for molding beads foam, wherein: The molding material filling space of the mold has a pair of opposite surfaces. The molding material filling space is connected to one or more feeders, One of the pair of surfaces has a discharge port of the feeder at one or more locations, One or more of the feeders are the feeders according to claim 1 or 2. 16 . The beads foam molding die according to claim 14 , further comprising a vent hole near a discharge port of the feeder.

17. A method for producing a bead foam, comprising the following steps: A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body. The method is characterized by the following (A) or (B): (A) The molding material filling space of the mold has a pair of opposing surfaces, One of the pair of surfaces has a discharge port of the feeder, The other side has a breathable plug. The thickness of the molding material filling space at the discharge port of the feeder is 5 mm or less. In a viewing angle perpendicular to the one surface, a portion or all of at least one vent plug on the other surface is within the area occupied by the discharge port of the feeder; (B) The molding material-filled space of the mold has a portion corresponding to the runner portion of the beads foam molded by the mold that is cut away during use. The portion corresponding to the flow channel portion has a discharge port of the feeder, The thickness of the molding material-filled space at the portion where the discharge port of the feeder exists is 5 mm or less.

18. A manufacturing method comprising the following steps: A step of filling thermoplastic resin beads into a molding material filling space of a mold via one or more feeders; and The process of performing bead foaming molding on thermoplastic resin beads filled in the molding material filling space of the mold to form a bead foam body. The molding material filling space of the mold has a pair of opposite surfaces, One of the pair of surfaces has a discharge port of the feeder at one or more locations, An intersection point of the inclined flow paths of the feeder exists in the molding material filling space.

19. The method for producing a beads foam according to claim 17 or 18, wherein: A vent hole is provided near the discharge port of the feeder.

Images