JP2019147323A - Method for manufacturing foamed resin molded product and foamed resin molded product - Google Patents

Abstract

To ensure sufficient fastening strength of a foamed resin molded product.SOLUTION: A method for manufacturing a plate-like foamed resin molded product 20 having a fastening hole 21 for fastening a fastening part 17 has a mold closing step of temporarily closing a mold 51 having a first molding surface 53A, a general part molding surface 55A, and an extended part molding surface 57A, a molten resin filling step of filling a molten resin 59 containing a foaming agent into a cavity 51A of the mold 51 that is temporarily closed, and a core back step of increasing a cavity width between the general part molding surface 55A and the first molding surface 53A so that a core back amount of the general part molding surface 55A is larger than a core back amount of the extended part molding surface 57A in a state where the cavity 51A is filled with the molten resin 59, and forming a foam layer 31 between the general part molding surface 55A and the first molding surface 53A.SELECTED DRAWING: Figure 6

Description

  The technology disclosed in this specification relates to a method for producing a foamed resin molded product and a foamed resin molded product.

  As a fixing structure of a foamed resin molded product, one described in Patent Document 1 below is known. In Patent Document 1, there is provided a load reducing body around the through-hole into which the fastener is inserted, and on the surface of the foamed resin molded product, which makes it difficult to transmit the load from the fastener to the inside of the foamed resin molded product. It is described that. Further, it is described that the provision of the load reducing body prevents the foamed layer from being crushed, so that the skin layer is not broken and the door trim can be firmly fixed to the vehicle body panel with a fastener.

JP 2012-200909 A

  In recent years, there has been a demand for a foamed resin molded article having a high foaming ratio that is lightweight and capable of reducing the amount of resin material used. However, the foamed resin molded product has a problem that the higher the foaming ratio, the easier it is for the shape of the hole edge of the fastening hole to sag from the expected shape, and it is difficult to secure a fastening surface for fastening the fastening member. Has occurred.

  In the configuration as disclosed in Patent Document 1, the load reducing body is locally provided on the surface of the portion having the foamed layer at the hole edge of the fastening hole. For this reason, depending on the expansion ratio of the foamed resin molded product, the load reducing body is also drawn into the fastening hole following the shape sag of the fastening hole, and a sufficient fastening surface is secured at the fastening hole. There is concern that it is difficult.

  The technology disclosed in the present specification has been completed based on such circumstances, and an object thereof is to make the fastening strength of the foamed resin molded article sufficient even at a high foaming ratio.

  The method for producing a foamed resin molded product disclosed in the present specification is a method for producing a plate-like foamed resin molded product having a fastening hole for fastening a fastening portion, and one plate surface of the foamed resin molded product From the first molding surface, a general molding surface that molds a general part of the other plate surface having a predetermined cavity width between the first molding surface and the first molding surface. A mold having an extension portion molding surface for molding a plurality of extension portions extending from the fastening hole toward the outer side in the circumferential direction among the other plate surfaces spaced apart from a predetermined cavity width; A mold closing step for temporarily closing the mold, a molten resin filling step for filling a molten resin containing a foaming agent into a cavity of the mold that has been temporarily closed, and a state in which the molten resin is filled in the cavity The core back amount of the general part molding surface is the extension part. The cavity width between the general part molding surface and the first molding surface is increased so as to be larger than the core back amount of the profile surface, and the space between the general part molding surface and the first molding surface is increased. And a core back step of forming a foam layer.

  According to such a method for producing a foamed resin molded product, the extension portion and the general portion are formed so that the core back amount of the general portion molding surface is larger than the core back amount of the extension portion molding surface. Since it is molded, it can be formed such that a plurality of extending portions having a lower expansion ratio than the general portion are partially included in the foam layer. For this reason, at the hole edge of the fastening hole, even if it is difficult to secure a fastening surface for fastening the fastening part by sagging the general part having a foam layer with a high foaming ratio from the expected shape, The fastening surface can be secured by a plurality of extending portions that are difficult to sag at a low expansion ratio. Moreover, when such an extended part is partly included in the foamed layer, it is possible to receive the fastening force applied to the plurality of extended parts at the general part. As a result, the fastening strength of the foamed resin molded product can be made sufficient.

  In the core back step, the general part molding surface may be retracted to the same position as the extended part molding surface. According to such a configuration, the fastening surface of the fastening portion can be configured in the general portion as well as the plurality of extending portions, and the fastening strength of the foamed resin molded product can be further increased. .

  Further, the foamed resin molded product disclosed in the present specification is a plate-like foamed resin molded product having a fastening hole for fastening a fastening portion, and a general part having a foamed layer therein, and the fastening hole A plurality of extending portions extending from the edge of the hole toward the outside in the circumferential direction and having a foaming ratio lower than that of the foamed layer, and at least a part of the extended portion is included in the foamed layer. Is formed.

  According to such a foamed resin molded product, a fastening surface for fastening the fastening portion is secured by sagging the general portion having a foam layer with a high foaming ratio at the hole edge of the fastening hole from the expected shape. Even if it is difficult to achieve, a fastening surface can be secured by a plurality of extended portions that are difficult to sag at a low foaming ratio, and a plurality of such extended portions are inherent in the foam layer, thereby The fastening force applied to the extending portion can be received by the general portion. As a result, the fastening strength of the foamed resin molded product can be made sufficient.

  The general part and the extended part may be formed flush with each other on one plate surface. According to such a configuration, the fastening surface of the fastening portion can be configured in the general portion as well as the plurality of extending portions, and the fastening strength of the foamed resin molded product can be further increased. .

  The plurality of extending portions may be arranged so as to extend radially from the fastening holes. According to such a configuration, the fastening force applied to the fastening surface can be distributed and received by the plurality of extending portions, and the foamed resin molded product can be fastened stably.

  According to the technique disclosed in this specification, the fastening strength of the foamed resin molded product can be made sufficient.

The front view of a door trim provided with the upper board concerning Embodiment 1. Partial sectional view in which the fastening portion between the upper board and the middle board is cut at a position corresponding to the extended portion (corresponding to a sectional view taken along line II-II in FIG. 1) Exploded perspective view showing fastening part and fastening hole (A) is sectional drawing of the 1st shaping | molding die and 2nd shaping | molding die showing a mold closing process, (B) is sectional drawing of the 1st shaping | molding die and 2nd shaping | molding die showing a molten resin filling process, (C) is a core Sectional drawing of the 1st shaping | molding die and 2nd shaping | molding die showing a back process (corresponding to the figure cut | disconnected by the IV-IV line of FIG. 3) (A) is sectional drawing of the 1st shaping | molding die and split type | mold showing a mold closing process, (B) is sectional drawing of the 1st shaping | molding die and split type | mold showing a molten resin filling process, (C) represents a core back process. Sectional drawing of a 1st shaping | molding die and a division | segmentation type | mold (corresponding to the figure cut | disconnected by the VV line | wire of FIG. 3) (A) is a sectional view around the hole forming portion representing the mold closing step, (B) is a sectional view around the hole forming portion representing the molten resin filling step, and (C) is a hole forming portion representing the core back step. Cross-sectional view of the surrounding area (corresponding to the view cut along line VI-VI in FIG. 3) Partial sectional drawing which cut | disconnected the fastening part of the upper board and middle board which concern on Embodiment 2 in the position corresponded to a general part.

<Embodiment 1>
Embodiment 1 will be described with reference to FIGS. 1 to 6. In this embodiment, what is used for the door trim 10 which is an interior material for vehicles is illustrated as a foamed resin molded product.

  As shown in FIG. 1, the door trim 10 is mainly configured by a trim board 11 in which a plurality of board members are fastened to each other. In the present embodiment, in the trim board 11, an upper board 20 that is an example of a foamed resin molded product and a middle board 13 (member to be fastened) are fastened to each other via a fastening portion 17. The upper board 20 is composed of a plate-like member made of a resin material such as polypropylene resin having bubbles 31A inside (see FIG. 4).

  As shown in FIG. 2, the middle board 13 is composed of a plate member made of a resin material such as polypropylene resin. The middle board 13 is integrally provided with a mounting boss 14 on the outer surface of the upper end portion of the passenger compartment. A rib 15 that reinforces the mounting boss 14 is provided around the mounting boss 14 to constitute a seat surface on which the upper board 20 (the flange portion 23) is placed.

  As shown in FIG. 2, the fastening portion 17 includes a head portion 17A and a shaft portion 17B. In the present embodiment, the fastening portion 17 includes an attachment boss 14 and a fastener 18 such as a screw screwed to the attachment boss 14. In other words, the fastening portion 17 is configured by the head 17 </ b> A including the head of the fastener 18, and the shaft portion 17 </ b> B including the mounting boss 14 in which the shaft of the fastener 18 is screwed.

  As shown in FIGS. 2 and 3, the upper board 20 has a fastening hole 21 for fastening the fastening portion 17. Specifically, the upper board 20 is provided with a flange-like flange portion 23 so as to extend downward. A surface 20A (one plate surface) of the flange portion 23 on the vehicle interior side and the vehicle exterior side. A fastening hole 21 having a circular shape in plan view is formed so as to open on the surface 20B (the other plate surface). A mounting boss 14 is inserted into the fastening hole 21 from the vehicle interior side so that the upper end of the middle board 13 overlaps the vehicle interior side of the flange portion 23. The fastening portion 17 is locked to the hole edge 21 </ b> A of the fastening hole 21 from the outside of the vehicle compartment by screwing the fastening tool 18 into the mounting boss 14 inserted through the fastening hole 21 from the outside of the compartment of the flange portion 23. It is the composition which becomes.

  As shown in FIGS. 3 to 6, the upper board 20 includes a general part 30 having a foam layer 31 inside, and a foam layer 31 extending from the hole edge 21 </ b> A of the fastening hole 21 toward the outer side in the circumferential direction. A plurality of extending portions 40 having a lower expansion ratio. In each figure, the foam layer 31 is schematically depicted as a portion having bubbles 31A, and the extended portion 40 and the skin layer 33 having a low foaming ratio are hatched.

  As shown in FIG. 4, an unfoamed or slightly foamed skin layer 33 having a lower foaming ratio than the foamed layer 31 is formed on the general portion 30. The general portion 30 has a configuration in which the core back amount of the general portion molding surface 55A described later is large, that is, the foam layer 31 has a high expansion ratio, so that the skin layer 33 is connected to the fastening hole 21 at the hole edge 21A of the fastening hole 21. An inclined surface 35 is formed so as to be drawn into the.

  As shown in FIG. 5 and FIG. 6, the extending portion 40 is formed so that at least a part thereof is inherent in the foam layer 31. The extending portion 40 is set to a width dimension such that the molten resin filled therein can be solidified in an unfoamed or slightly foamed state in a filling step described later. The extending portion 40 is formed in an unfoamed or finely foamed rib shape having a height dimension larger than the thickness dimension of the skin layer 33, and is formed so that the root portion is embedded in the foamed layer 31. In the present embodiment, the general portion 30 and the extending portion 40 are formed flush with each other on the surface 20A of the upper board 20 outside the passenger compartment. That is, the extended portion 40 has a rib front end surface 40 </ b> A arranged at the same position as the skin layer 33 of the general portion 30 in the thickness direction of the upper board 20. Of these, only the rib front end surface 40A and a protrusion 41 described later appear (see FIG. 3). In addition, between the rib front end surface 40A and the skin layer 33 of the general portion 30, a linear seam or a step (not shown) may be formed so that the skin layer 33 is folded.

  As shown in FIG. 3, the plurality of extending portions 40 are arranged so as to extend radially from the fastening holes 21. Each of the plurality of extending portions 40 includes, at the hole edge 21 </ b> A of the fastening hole 21, a protruding portion 41 that protrudes in the circumferential direction, and an extending portion 43 that extends from the protruding portion 41 to the inside of the general portion 30. have. The protruding portion 41 is a portion that protrudes relatively from the inclined surface 35 when the general portion 30 located around the extending portion 40 is bent from the intended shape at the hole edge 21A of the fastening hole 21. . The extension portion 43 extends at least radially outward from the head portion 17A of the fastening portion 17. With such a configuration, the head 17 </ b> A of the fastening portion 17 can be stably supported by the plurality of protrusions 41, and the fastening force applied to the protrusion 41 can also be received by the general portion 30 via the extension portion 43. Is possible.

  Then, the manufacturing method of the upper board 20 of this embodiment is demonstrated, referring FIGS. 4-6. The upper board 20 is molded by injection foam molding using the molding apparatus 50. The molding device 50 includes an injection device (not shown) and a molding die 51 to which a molten resin 59 is supplied from the injection device.

  The mold 51 includes a first mold 53 and a second mold 55 that can be opened and closed with each other, and a split mold 57 incorporated in the second mold 55. The first molding die 53 has a first molding surface 53A for molding the surface 20A on the vehicle interior side of the upper board 20. The 2nd shaping | molding die 55 has 55 A of general part shaping | molding surfaces which shape | mold the general part 30 among the surfaces 20B of the vehicle interior outer side in the upper board 20. FIG. The split mold 57 has an extended portion forming surface 57A for forming a plurality of extended portions 40 in the surface 20B on the outer side of the upper board 20. The cavity 51A of the molding die 51 is a space defined by the first molding surface 53A, the general part molding surface 55A, and the extended part molding surface 57A.

  In the present embodiment, an example is given of a molding die 51 in which the first molding die 53 is a fixed die and the second molding die 55 is a movable die. As shown in FIG. 6, the split mold 57 is incorporated in an opening 55 </ b> B that opens to the general part molding surface 55 </ b> A, and is nested so as not to follow the movement of the second mold 55. The split mold 57 is incorporated into the second mold 55 such that the extended portion molding surface 57A is positioned by retracting a predetermined amount D from the general portion molding surface 55A. Hereinafter, the position of the second molding die 55 in this state is referred to as an initial position. At the initial position of the second mold 55, an extension portion forming space 51B for forming the extension portion 40 is defined by the extension portion forming surface 57A and the inner surface of the opening 55B. The molding die 51 cores the second molding die 55 from the initial position, thereby maintaining the cavity width between the extension portion molding surface 57A and the first molding surface 53A while maintaining the general part molding surface 55A. The cavity width between the first molding surface 53A and the first molding surface 53A can be increased. Hereinafter, the position where the second mold 55 is core-backed is referred to as a core-back position.

  As shown in FIG. 5, the first mold 53 is provided with a hole forming portion 54 that protrudes from the first molding surface 53 </ b> A and forms the fastening hole 21. In the second mold 55, a fitting portion 56 that fits with the hole forming portion 54 is recessed at a position facing the hole forming portion 54 in the general portion forming surface 55A. With such a configuration, the fastening hole 21 can be formed through the upper board 20 in the thickness direction in the cavity 51 </ b> A of the mold 51.

  The manufacturing method of the upper board 20 includes a mold closing process in which the mold 51 is temporarily closed and a molten resin filling in which the cavity 51A of the mold 51 that has been temporarily closed is filled with a molten resin 59 containing a foaming agent. And a core back step of forming the foamed layer 31 between the general part molding surface 55A and the first molding surface 53A.

  In the mold closing step, the general part molding surface 55A is disposed with a predetermined cavity width C between the first molding surface 53A and extends away from the first molding surface 53A by a distance greater than the predetermined cavity width C. A partial molding surface 57A is arranged. That is, the second molding die 55 and the first molding die 53 are closed with the second molding die 55 as the initial position. At this time, the predetermined cavity width C is smaller than the plate thickness of the flange portion 23, and the separation distance between the first molding surface 53A and the extension portion molding surface 57A is set to be approximately equal to the plate thickness of the flange portion 23. Has been.

  In the molten resin filling step, a molten resin 59 containing a foaming agent is injected from the injection device into the cavity 51A and filled into the cavity 51A. At this time, portions of the molten resin 59 that are in contact with the side surfaces of the first molding surface 53A, the general portion molding surface 55A, and the hole forming portion 54 are cooled and solidified to form the skin layer 33. In addition, a portion of the molten resin 59 filled in the extension portion forming space 51 </ b> B is cooled and solidified to form the extension portion 40. In the molten resin filling step, the internal pressure in the cavity 51A is kept high, and the foaming agent is kept almost unfoamed.

  In the core back step, the general part molding surface is set so that the core back amount of the general part molding surface 55A is larger than the core back amount of the extension part molding surface 57A in a state where the cavity 51A is filled with the molten resin 59. The cavity width between 55A and the first molding surface 53A is increased. Specifically, the second molding die 55 is moved from the initial position to the core back position, and the general part molding surface 55A is core-backed by a predetermined amount D from the first molding surface 53A in the width direction of the cavity 51A (general part). The core back amount of the molding surface 55A = D> 0), and the extended portion molding surface 57A is maintained in a state where the core back is not back from the first molding surface 53A (core back amount of the extension portion molding surface 57A = 0). Then, the internal pressure of the cavity 51 </ b> A decreases, the foaming agent foams, and the foam layer 31 is formed in the general part 30.

  In the core back process of the present embodiment, the general part molding surface 55A is retracted to the same position as the extension part molding surface 57A. As a result, the rib front end surface 40A of the extended portion 40 and the skin layer 33 of the general portion 30 are formed flush with each other on the outer surface 20B of the upper board 20. The foam layer 31 is also formed around the extension 43 in the extension 40, and the extension 40 is in the foam layer 31.

  In the process of core-backing the general part molding surface 55A, the skin layer 33 formed by the general part molding surface 55A is formed around the hole forming part 54 around the hole forming part 54, and exists in a cylindrical shape. An inclined surface 35 that is inclined toward the inside of the fastening hole 21 is formed so as to be drawn into the side 33 (see FIG. 4C). On the other hand, since the extension portion molding surface 57A does not core-back, the force directed to the inside of the fastening hole 21 acting on the extension portion 40 is small, and the extension portion 40 has a thickness dimension ( The protrusion 41 is formed by having a configuration in which the height dimension of the rib shape is large and the rigidity is high (see FIG. 5C). After the core back process, when the molten resin 59 in the cavity 51A is cooled and solidified, the upper board 20 is obtained.

  Then, the effect of this embodiment is demonstrated. According to the manufacturing method of the upper board 20 of the present embodiment, the extension portion 40 and the general portion are formed so that the core back amount of the general portion molding surface 55A is larger than the core back amount of the extension portion molding surface 57A. Since the portion 30 is formed, the plurality of extending portions 40 having a lower expansion ratio than the general portion 30 are formed so as to be partially included in the foam layer 31. And according to such an upper board 20, in the hole edge 21A of the fastening hole 21, the fastening part 17 is fastened by the general part 30 having the foaming layer 31 having a high foaming ratio falling from its intended shape. Therefore, even if it is difficult to secure the fastening surface, the fastening surface can be secured by the plurality of extending portions 40 that are difficult to sag at a low expansion ratio. In addition, since the extended portion 40 is partially included in the foamed layer 31, the general portion 30 can receive the fastening force applied to the plurality of extended portions 40. As a result, the fastening strength of the upper board 20 can be made sufficient.

  In the present embodiment, the general part molding surface 55A is retracted to the same position as the extended part molding surface 57A in the core back step. In the upper board 20, the general portion 30 and the extending portion 40 are formed flush with each other on the outer surface 20B of the passenger compartment. For this reason, the fastening surface of the fastening portion 17 can be configured in the general portion 30 together with the plurality of extending portions 40, and the fastening strength of the upper board 20 can be further increased.

  In the present embodiment, the plurality of extending portions 40 are arranged so as to extend radially from the fastening holes 21. For this reason, the fastening force applied to the fastening surface can be distributed and received by the plurality of extending portions 40, and the upper board 20 can be stably fastened.

<Embodiment 2>
Next, Embodiment 2 Embodiment 1 will be described with reference to FIG. In this embodiment, the door trim 110 in which the configuration of the fastening portion is different from that of the first embodiment is illustrated. The same parts as those in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The fastening portion 117 has a head portion 17A and a shaft portion 17B. In the present embodiment, the fastening portion 117 has a head portion 17 </ b> A and a shaft portion 17 </ b> B formed by caulking the mounting boss 114 erected on the middle board 13. A mounting boss 114 is inserted into the fastening hole 21 from the vehicle interior side so that the upper end portion of the middle board 13 overlaps the vehicle interior side of the flange portion 23. The front end portion 114A of the mounting boss 114 inserted through the fastening hole 21 is melted by using a caulking means such as an ultrasonic horn to form a head portion 17A having a diameter larger than the diameter of the fastening hole 21, whereby the fastening portion 117. Is locked to the hole edge 21A of the fastening hole 21 from the outside of the passenger compartment. In FIG. 7, the mounting boss 114 before the tip end portion 114 </ b> A is melted is indicated by a two-dot chain line.

  In this embodiment, since the inclined surface 35 is formed by the shape sag in the general portion 30 at the hole edge 21A of the fastening hole 21, the inclined surface 35 becomes a guide for the molten resin, and a part of the molten resin is fastened. The inside of the hole 21 can be filled. Furthermore, a plurality of protrusions 41 configured by a part of the extended portion 40 are arranged on the hole edge 21A of the fastening hole 21 so as to be scattered in the circumferential direction. Compared to a configuration that does not have a contact area, the ground contact area between the molten resin and the hole edge 21A is large. As a result, the fastening strength between the upper board 20 and the middle board 13 by the fastening part 117 can be improved.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, the scope not deviating from the gist other than the following. It can be implemented with various changes.
(1) In the above embodiment, the configuration in which only the second mold is moved in the molding apparatus is illustrated, but the configuration of the molding apparatus is not limited to this. For example, the second mold may be a fixed mold, and the first mold and the split mold may be moved together. Also, when the second mold is moved, the split mold is also moved by the second mold. It may be configured to move by a movement amount smaller than the amount.
(2) In the above embodiment, the general part molding surface is retracted to the same position as the extension part molding surface, and the general part and the extension part are formed to be flush with each other on the surface of the upper board outside the passenger compartment. Although the configuration is exemplified, the configuration is not limited to this. For example, it is good also as a structure which makes a general part shaping | molding surface retreat to the front of an extension part shaping | molding surface, and a part of extension part protrudes in a rib shape from a general part.
(3) In the above embodiment, the configuration in which the plurality of extending portions are arranged so as to extend radially from the fastening holes is exemplified, but the present invention is not limited thereto. If the plurality of extending portions are at least two or more, the head portion of the fastening portion can be supported. Further, the shape of each extending portion is not limited to a rib shape, and may be a tapered shape in which the width dimension and / or the height dimension decrease as the distance from the fastening hole increases.
(4) In addition to the above embodiment, the shape, material, fastening hole and fastening portion configuration of the foamed resin molded product can be changed as appropriate.
(5) In the above embodiment, the vehicle interior material and the manufacturing method thereof are exemplified as the foamed resin molded product and the manufacturing method thereof. However, the foamed resin molded product is widely used in the construction related field as well as the automobile related field. can do. In particular, it is suitable for interior materials, exterior materials and structural materials for automobiles, railway vehicles, ships and airplanes, etc., and among them, it is suitable for automotive interior materials and the like. Furthermore, it is also suitable for interior materials, exterior materials and structural materials such as buildings and furniture. In addition, it is also suitable as a package, a container (such as a tray), a protective member, and a partition member.

  DESCRIPTION OF SYMBOLS 17,117 ... Fastening part, 20 ... Upper board (foamed resin molded product), 20A ... Vehicle interior side surface (one plate surface), 20B ... Vehicle interior side surface (the other plate surface), 21 ... Fastening hole 30 ... General part, 31 ... Foam layer, 40 ... Extension part, 51 ... Mold, 51A ... Cavity, 53A ... First molding surface, 55A ... General part molding surface, 57A ... Extension part molding surface, 59 ... Molten resin

Claims (5)

A method for producing a plate-like foamed resin molded article having a fastening hole for fastening a fastening portion,
General part molding having a predetermined cavity width between a first molding surface for molding one plate surface of the foamed resin molded product and the first molding surface, and molding a general portion of the other plate surface An extended portion for forming a plurality of extending portions extending from the fastening hole toward the outer side in the circumferential direction on the other plate surface and spaced apart from the first molding surface by a distance greater than the predetermined cavity width A mold closing step for temporarily closing a mold having a part molding surface;
A molten resin filling step of filling a molten resin containing a foaming agent into a cavity of the mold that is temporarily closed;
In a state where the cavity is filled with the molten resin, the general part molding surface and the first part are formed such that the core back amount of the general part molding surface is larger than the core back amount of the extension part molding surface. A core back step of increasing a cavity width between the molding surface and forming a foamed layer between the general part molding surface and the first molding surface.   The method for producing a foamed resin molded article according to claim 1, wherein in the core back step, the general part molding surface is retracted to the same position as the extension part molding surface. A plate-like foamed resin molded product having a fastening hole for fastening a fastening part,
A general part having a foam layer inside;
A plurality of extending portions extending from the hole edge of the fastening hole toward the outer side in the circumferential direction and having a lower expansion ratio than the foam layer;
The extended portion is a foamed resin molded article formed so that at least a part thereof is inherent in the foamed layer.   The foamed resin molded product according to claim 3, wherein the general portion and the extended portion are formed flush with each other on one plate surface.   The foamed resin molded product according to claim 3 or 4, wherein the plurality of extending portions are arranged so as to extend radially from the fastening holes.

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