JP5013474B2 - Foamed resin molded product - Google Patents

Description

  In the present invention, after the movable side mold and the fixed side mold are clamped, the foamed resin material is filled into the cavity, and further, the movable side mold is retracted to secure a foaming space. In particular, the present invention relates to a foamed resin molded product formed into a required shape, and in particular, it is possible to prevent as much as possible the deformation of the entire length of the peripheral edge of the product or the tip of the vertical wall portion provided at a part of the peripheral edge, and The present invention relates to a foamed resin molded article in which gloss unevenness or the like does not occur on the surface of a wall portion and appearance performance and accuracy of matching with adjacent parts are improved.

  FIG. 11 shows an automotive door trim 1 mounted on the interior side of a door panel (not shown). The door trim 1 is lightweight, has excellent rigidity and impact resistance, and is inexpensive. Many foamed resin molded products such as polypropylene (PP) foam are used. The door trim 1 is integrally formed with an armrest portion 1a that bulges toward the indoor side. A door pocket opening 1b is formed below the armrest portion 1a, and a speaker grill 1c is provided on the front side of the door trim. 1 or a separate body. In addition, the vertical wall part 1d which faces the panel side is integrated with the full length of the periphery of the door trim 1, or a part of periphery.

  And the conventional molding method which shape | molds the door trim 1 using this kind of foamed resin molded product in a required shape is demonstrated based on FIG. 12, FIG. FIG. 12 shows a schematic configuration of the molding die, and FIG. 13 shows a press chart of the molding die. The molding die 2 is generally composed of a movable side die 3 and a fixed side die 4, and the movable side die 3 can be moved up and down by a predetermined stroke by driving the elevating cylinder 3 a. On the other hand, mold opening and mold clamping are performed. In addition, an injection machine (not shown) is connected to the stationary mold 4, and a foamed resin material M supplied from the injection machine is injected and filled into the cavity C between the molds 3 and 4. Here, in the initial mold state at the time of mold clamping, the mold position of the movable side mold 3 is the position (a1) in the press chart diagram of FIG. 13, and in this state, the foaming resin material M is transferred from the injection machine. Is injected and filled in a cavity C defined between the movable mold 3 and the fixed mold 4.

  Then, after a certain period of time, the movable mold 3 is moved in the mold opening direction, and is opened to the position (a2) in the press chart diagram of FIG. The door trim 1 is molded. That is, since the clearance between the movable mold 3 and the fixed mold 4 is set to be small when the mold position is the position (a1) in FIG. 13, the foaming reaction of the foamed resin material M is suppressed. The foamed resin material M can be quickly injected and filled into the cavity C. In the filled foamed resin material M, a solid layer is immediately formed at a portion in contact with the mold surface of the movable side mold 3 and the fixed side mold 4, but the inside remains unfoamed. Then, if the mold position is opened to the position (a2) in FIG. 13, that is, the mold clearance between the movable mold 3 and the fixed mold 4 is set slightly wider, thereby securing a foaming space. The door trim 1 can be molded into the final product shape by smoothly performing the foaming reaction of the foamed resin material inside the solid layer.

  A forming process of the vertical wall portion 1d formed on the peripheral portion of the door trim 1 formed as described above will be described with reference to FIGS. First, a point (a) in the press chart diagram of FIG. 13 is a state in which the movable side mold 3 and the fixed side mold 4 are clamped, that is, a state before injection filling, and FIG. As shown, the mold clearance of the general portion is 2.0 mm, whereas the mold clearance of the vertical wall portion 1d is set to 2.5 mm or more. Then, at the point (b) in the press chart in FIG. 13, as shown in FIG. 14 (b), the foamed resin material M is injected and filled into the cavity C, and in particular, solidification starts in the solid layer on the outer surface. Become. At this time, in order to form the foam layer inside the solid layer, the movable side mold 3 is raised as shown in FIG. 14C, and the mold clearance of the general part is secured up to 3.6 mm. In the case of FIG. 14C, the foamed resin material M inside the solid layer formed on the outer surface remains unfoamed.

  Thereafter, as shown in FIG. 14 (d), the foamed resin material M in an unfoamed state is foamed in the general wall portion as well as the vertical wall portion 1d, and the foam layer b is formed inside the solid layer a. Molding of the door trim 1 having the portion 1d is completed. A conventional example of the method for molding the foamed resin molded product is described in detail in Patent Document 1.

JP 2002-120252 A

  Thus, in the conventional method for molding a foamed resin molded product, the movable side mold 3 is retracted when the movable side mold 3 is retracted as shown in FIG. Since a clearance (indicated by L in the figure) is generated between the mold 3 and the fixed mold 4, the restriction by the mold surface of the movable mold 3 is released. As a result, the foaming pressure of the foamed resin material M causes the terminal Deformation is likely to occur in the portion, and the degree of occurrence of this deformation tends to become more prominent as the plate thickness increases.

  Therefore, the outer peripheral line of the foam resin molded product peripheral part is easy to meander, and there is a disadvantage that the appearance performance is remarkably deteriorated, and there is a problem such as interference with adjacent parts, and the alignment accuracy is lowered. Is also pointed out at the same time.

  The present invention has been made in view of such circumstances, and after the movable side mold and the fixed side mold are clamped, the foamed resin material is injected and filled into the cavity, and then the movable side mold is retracted. A foamed resin molded product having a foamed layer inside a solid layer formed by inducing a foaming reaction in a state where a foaming space is secured and molded into a required shape, and having a full length of the foamed resin molded product or one of the peripheral edges. An object of the present invention is to provide a foamed resin molded product that improves the appearance appearance and improves the accuracy of alignment with adjacent parts by preventing deformation and gloss unevenness at the tip of the vertical wall portion provided in the portion.

In order to achieve the above object, the present invention, after injecting and filling the foamed resin material into the cavity defined between the movable mold and the fixed mold, the movable mold is moved backward, After securing a foaming space, by foaming the foamed resin material, the foamed resin molded product is molded into a required shape, and in the foamed resin molded product having a solid layer on the outer surface and a foamed layer on the inside, A vertical wall portion is provided at the entire length of the peripheral edge of the foamed resin molded product or a part of the peripheral edge, and a thin-walled portion consisting only of a solid layer is set at the front end portion of the vertical wall portion. A plate thickness gradually changing portion is formed between the thin wall portion and the thickness thereof changes gently . The inner surface of the plate thickness gradually changing portion from the vertical wall portion to the thin wall portion is processed into a concave R surface. , this proportion of the solid layer is set to be larger The features.

  Here, the molding die used for molding the foamed resin molded product is composed of a movable side die, a fixed side die, and an injection machine connected to the fixed side die. The movable mold moves up and down from the mold opening position to the mold clamping position (bottom dead center) by the operation of the drive cylinder. Further, in order to secure a foaming space for the foamed resin material, the movable side mold moves backward by a small stroke and then moves to the mold opening position. That is, the movable side mold takes three positions: a mold opening position, a mold clamping position, and a foaming position where a mold clearance is secured a little from the mold clamping position.

  On the other hand, the fixed-side mold has a hot runner as a resin passage for injecting and filling the foamed resin material supplied from the injection machine into a cavity defined between the movable-side mold and the fixed-side mold. A valve gate is provided, and an ejector mechanism such as an ejector pin for projecting a foamed resin molded product after molding is provided.

  Then, in the cavity shape defined between the movable side mold and the fixed side mold, the vertical wall is formed so that the vertical wall portion is formed on the entire length of the peripheral edge of the foamed resin molded product or on a part of the peripheral edge. The cavity is set to the fixed side mold so that the thickness of the tip of the cavity for the vertical wall is halved, and the thickness of the cavity for the vertical wall is set to the tip. It has been adjusted to change gently toward. In addition, this vertical wall part is provided in order to give a three-dimensional feeling and rigidity to a product. As for the dimensional relationship between the vertical wall part and the thin part, the thickness of the thin part is 1.0 to 2.0 mm, the height of the thin part is 0.5 to 2.0 mm, and the gradual change part where the plate thickness gradually changes. The length is preferably 1.0 mm or more.

  Next, as the material of the foamed resin molded product, a thermoplastic resin in which a foaming agent is mixed is used. For example, the thermoplastic resin used is polyethylene resin, polypropylene resin, polystyrene resin, polyethylene terephthalate resin, polyvinyl alcohol resin, vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin. The resin is suitably selected from acrylonitrile / butadiene / styrene (ABS) resin and the like. On the other hand, as the foaming agent, an organic foaming agent such as azodicarbonamide or an inorganic foaming agent such as sodium bicarbonate can be used.

  Therefore, if the movable mold is driven to the bottom dead center and the movable mold and the fixed mold are clamped, the foamed resin material is injected and filled into the cavity defined between the two. As the time passes, the portion that contacts the mold surface is cooled and solidified, so that a solid layer is formed from the outer surface toward the inside. Then, after a certain period of time, if the movable side mold moves in the mold opening direction and the movable side mold is stopped with the mold clearance between the movable side mold and the fixed side mold secured, foaming is possible. By the foaming reaction of the resin material, a foam layer is formed in the solid layer, and a foamed resin molded product having a predetermined thickness is molded into a required shape.

  As is clear from the above configuration, after the foamed resin material is injected and filled into the cavity defined by the mold clamping operation of the movable side mold and the fixed side mold, the movable side mold is retracted in the mold opening direction. By operating, the foaming resin material is allowed to undergo a foaming reaction in a state where a foaming space is secured, and a foamed resin molded product having a foamed layer in a solid layer can be molded into a required shape. At that time, since the thin wall part consisting only of the solid layer is formed at the tip of the vertical wall part provided at the full length of the peripheral part of the product or a part of the peripheral part, it is movable by the mold opening operation of the movable side mold. Even if the restraint by the mold surface of the side mold is released, the thin wall portion is not deformed because the foaming internal pressure is not applied. Furthermore, since the thickness is gradually changed from the thin wall portion to the vertical wall portion, uneven gloss and the like do not occur in appearance.

In the present invention, as described above, the inner surface of the plate thickness gradually changing portion from the vertical wall portion to the thin wall portion is subjected to concave R-surface processing, and a large proportion of the solid layer is set . For this reason, when the plate thickness is gradually changed from the vertical wall portion to the tip, since the concave R surface is formed on the inner surface of the plate thickness gradually changing portion, the ratio of the solid layer increases. The rigidity can be maintained more firmly.

  As described above, in the foamed resin molded product according to the present invention, after the foamed resin material is injected and filled into the cavity of the molding die, the movable side mold is moved backward to ensure a foaming space with a predetermined thickness. , Inducing a foaming reaction and molding a foamed resin molded product consisting of a solid layer and a foamed layer into the required shape. At that time, a vertical wall is provided at the full length of the product or part of the periphery. Since the thin wall portion consisting only of the solid layer is formed at the front end portion of the vertical wall portion, foaming internal pressure does not act on the thin wall portion, and defects such as meandering of the outer peripheral line that have occurred in the past have occurred in advance. Can be prevented.

  Furthermore, although the thickness of the foamed resin molded product according to the present invention changes from the vertical wall portion to the thin-walled portion, since the plate thickness is gently changed, gloss unevenness or the like does not occur on the surface, and is beautiful. The appearance can be maintained, and the appearance performance and the alignment accuracy with respect to adjacent parts can be improved.

  Hereinafter, an embodiment of a foamed resin molded product according to the present invention will be described in detail with reference to the accompanying drawings. Note that the gist of the present invention is as described in the scope of claims, and the contents of the embodiments described below are merely examples of the present invention.

  FIG. 1 to FIG. 10 show an embodiment of the present invention. FIG. 1 is a front view showing a door trim having an upper and lower split structure in which a foamed resin molded product according to the present invention is applied to a door trim lower, and FIG. FIG. 3 is a sectional view showing the configuration of the vertical wall portion of the door trim lower in the door trim, FIG. 4 is a schematic diagram showing the configuration of a molding die used for molding the door trim lower in the door trim, and FIG. 5 is a press chart diagram of the movable side mold in the molding die shown in FIG. 4, FIGS. 6 to 8 are explanatory views showing the molding process of the door trim lower, and FIGS. 9 and 10 are foamed resin moldings according to the present invention. It is each sectional drawing which shows the modification of goods.

  In FIG. 1 and FIG. 2, the automobile door trim 10 is composed of an upper and lower divided body of a door trim upper 20 and a door trim lower 30. An inside handle escutcheon 11 is attached to the door trim upper 20, and a pull handle 12 and a power window switch finisher 13 are attached to an armrest portion on which an occupant places an elbow. On the other hand, the door trim lower 30 is provided with a door pocket opening 14 capable of accommodating equipment, and a speaker grill 15 is provided integrally with or separately from the door trim lower 30 on the front side thereof.

  Further, as shown in FIG. 2, the door trim upper 20 and the door trim lower 30 are configured by a laminated structure in which a skin 22 is pasted on the surface of a resin core 21, as shown in FIG. 2. The synthetic resin used as the material of the resin core material 21 is polyethylene resin, polypropylene resin, polystyrene resin, polyethylene terephthalate resin, polyvinyl alcohol resin, vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin. , Ionomer-based resins, acrylonitrile / butadiene / styrene (ABS) resins, and the like may be appropriately selected. If desired, fillers such as talc, clay, and wood powder may be mixed into the synthetic resin. On the other hand, the skin 22 is made of a synthetic resin sheet such as a thermoplastic elastomer resin typified by thermoplastic olefin (TPO), or a synthetic resin sheet such as a laminated sheet material lined with a cushion layer such as polyethylene foam on the back side of the TPO sheet. it can.

  Further, in order to mold the door trim upper 20 into a desired shape, the injection molding method and the mold press molding method are suitable in consideration of mass productivity. That is, the outer skin 22 is set in a molding die, and the resin core material 21 is molded into a desired curved shape by injection filling the molten resin after the mold clamping or immediately before the mold clamping. The skin 22 can be integrally attached to the surface side. On the other hand, the door trim lower 30 uses a foamed resin molded product in the present invention, and a foaming agent is mixed in the synthetic resin. Synthetic resins that can be used are polyethylene resins, polypropylene resins, polystyrene resins, polyethylene terephthalate resins, polyvinyl alcohol resins, vinyl chloride resins, polyamide resins, polyacetal resins, polycarbonate resins, ionomer resins, acrylonitrile. / Butadiene / styrene (ABS) resin, etc. And what mixed organic foaming agents, such as azodicarbonamide, or inorganic foaming agents, such as sodium bicarbonate, with respect to a synthetic resin is used.

  The door trim 10 shown in FIG. 1 and FIG. 2 can obtain a good product appearance due to the accent effect on the appearance of the door trim upper 20 and the door trim lower 30 and can achieve a compact molding die. Moreover, the door trim lower 30 is made of a foamed resin molded product, which greatly contributes to weight reduction.

  By the way, as shown in FIG. 3, the door trim lower 30 has a vertical wall portion 33 bent toward the panel P side on both sides and a lower edge of the general portion 32 with respect to the general portion 32 which is the product surface. Further, a thin portion 34 is integrally formed at the tip portion. The vertical wall portion 33 is provided to give the door trim lower 30 a three-dimensional effect. Furthermore, the internal structure of the door trim lower 30 has a two-layer structure including a cell-structured foam layer 30b inside the solid layer 30a. The foam layer 30b extends from the general portion 32 to the vertical wall portion 33. However, the thin portion 34 is formed only by the solid layer 30a. Further, regarding the dimensional relationship, in this embodiment, the thickness t1 of the general portion 32 is 3.0 mm, the thickness t2 of the vertical wall portion 33 is 2.0 mm, the thickness A of the thin portion 34 is 1.0 mm, and the thin portion The height B of each plate 34 is set to 1.0 mm, and in particular, the plate thickness gradually changing portion 35 (the length dimension in FIG. 3 is α in FIG. 3) where the thickness gradually changes from the vertical wall portion 33 to the thin wall portion 34. Set). The thickness A of the thin portion 34 may be in the range of 1.0 to 2.0 mm, and the height B of the thin portion 34 may be in the range of 0.5 to 2.0 mm.

  Therefore, since the door trim lower 30 according to the present invention has the thin wall portion 34 made of only the solid layer 30a at the front end portion of the vertical wall portion 33, the deformation of the outer peripheral portion due to the foaming internal pressure is obviated when molding the door trim lower 30 described later. The outer peripheral line does not meander, and the plate thickness gradually changes from the vertical wall portion 33 to the thin wall portion 34 by the plate thickness gradual changing portion 35, so that there is no occurrence of uneven gloss on the appearance. The appearance appearance can be maintained well, and the alignment accuracy with respect to adjacent parts can be improved.

  Next, a schematic configuration of the molding die 40 used for molding the door trim lower 30 will be described with reference to FIG. The molding die 40 is generally composed of a movable die 50, a fixed die 60, and an injection machine 70. More specifically, the movable side mold 50 is driven to take three positions of a foaming position in addition to a mold opening position and a mold clamping position by an operation of a drive cylinder (not shown). On the other hand, in the fixed side mold 60, the molten resin is supplied to the mold surface through the hot runner 61 and the valve gate 62 which are resin passages of the molten resin supplied from the injection machine 70, and the molded resin molded product after the molding is used. An ejector pin 63 for projecting is provided.

  Furthermore, the door trim lower 30 is formed into a required shape along the shape of the cavity C defined between the movable side mold 50 and the fixed side mold 60, but the vertical wall portion 33 is formed on the periphery of the door trim lower 30. In the molding die 40, a vertical wall cavity C1 is set on the outer periphery of the cavity C. Further, a stepped portion 64 for forming a thin portion 34 provided at the distal end portion of the vertical wall portion 33 of the door trim lower 30 is provided in the fixed-side mold 60 at the distal end portion of the vertical wall portion cavity C1. In addition, an inclined surface 65 that forms a plate thickness gradually changing portion 35 set from the vertical wall portion 33 to the thin portion 34 is formed.

  5 shows a press chart of the movable mold 50 in the molding die 40, and FIGS. 6 to 8 show the molding process of the door trim lower 30 using the molding die 40 over time. That is, the movable mold 50 is moved by the operation of the drive cylinder from the mold opening position (point indicated by (a) in the press chart of FIG. 5), and the bottom dead center (the press of FIG. 5). The movable side mold 50 is clamped to a point where a certain clearance is maintained with respect to the fixed side mold 60.

  Further, after the movable side mold 50 is clamped with respect to the fixed side mold 60, the foamed resin material M is injected and filled into the cavity C from the injection machine 70 through the hot runner 61 and the valve gate 62 as shown in FIG. . The foamed resin material M is also injected and filled into the vertical wall cavity C1. At this time, although not shown, it is also possible to adopt a counter pressure method in which air is forcibly introduced from the outside into the cavity C and the resin is filled in the cavity C so that the foamed resin material M does not undergo a foaming reaction.

  And if the injection filling process of the foamed resin material M is completed, as shown by (c) to (d) in the press chart diagram of FIG. 5, the movable side mold 50 moves backward in the mold opening direction. 7, a foaming space indicated by a symbol S is secured. In this backward movement of the movable mold 50, as shown in FIG. 7, the dimension of the backward stroke is set to 1.6 mm so that the clearance of the general part is 3.6 mm. In addition, the dimension of the step part 64 provided in the fixed side metal mold | die 60 is set on the basis of the dimension of the backward stroke of the movable side metal mold | die 50. As shown in FIG. Furthermore, in the foaming process shown in (d) to (e) in the press chart diagram of FIG. 5, the foamed resin material M in the solid layer 30a is foamed to form the foamed layer 30b. As shown in FIG. A door trim lower 30 having a predetermined thickness is formed.

  In the present invention, when the movable side mold 50 shown in FIGS. 7 and 8 is retracted, a stepped portion is formed on the fixed side mold 60 so that the thin wall portion 34 is formed at the distal end portion of the vertical wall portion 33 in the door trim lower 30. 64 is set, and the plate thickness gradually changing portion 35 is set so that the thickness change between the vertical wall portion 33 and the thin wall portion 34 becomes gentle. The shape is set, and the thin portion 34 is composed of only the solid layer 30 a depending on the width dimension of the step portion 64. Thus, the tip portion of the vertical wall portion 33 in the door trim lower 30 is partially thinned by the mold shape, and the internal resin is solidified as the solid layer 30a without inducing a foaming reaction. No foaming internal pressure is applied to the outside, the appearance of the outer peripheral line of the vertical wall portion 33 is good, the alignment accuracy with respect to adjacent parts is improved, and the plate thickness change between the vertical wall portion 33 and the thin wall portion 34 is gentle. Therefore, gloss unevenness does not occur on the outer surface of the vertical wall portion 33, which is also a factor for maintaining good appearance performance.

  Next, FIGS. 9 and 10 show a modification of the door trim lower 30 to which the foamed resin molded product according to the present invention is applied. The structure of FIG. 9 has a thickness between the vertical wall portion 33 and the thin portion 34. The inner surface side of the plate thickness gradually changing portion 35 that reveals the change is processed into a concave R surface 35a. In this case, since the thin portion 34 is composed of only the solid layer 30a, the deformation can be prevented and the plate thickness is gradually changed by the plate thickness gradual changing portion 35, so that gloss unevenness does not occur. The same effect as the embodiment can be expected. In addition, in the plate thickness gradual change portion 35, since the concave-shaped R surface processing is performed on the inner surface, the ratio of the solid layer 30a is relatively large in the plate thickness gradual change portion 35 as compared with the foam layer 30b. Thus, there is an advantage that the rigidity of the vertical wall portion 33 can be further strengthened. Further, as shown in FIG. 10, the thickness A of the thin wall portion 34 is set to 1.0 mm or more, and the change in the plate thickness between the vertical wall portion 33 and the thin wall portion 34 is reduced to reduce the vertical wall portion 33 and the thin wall portion 34. The rigidity including can be further enhanced.

  Although the embodiment described above is applied to the door trim lower 30 in the upper and lower divided door trim 10, the application is not limited to this and can be applied to general foamed resin molded products. Further, as the structure of the molding die 40, in addition to using the valve gate 62, for example, a side gate type die can be used, and a core portion and a fixed side die are provided on the movable side die 50 side. A cavity portion can also be set on the 60 side. It is also possible to employ a counter pressure method for supplying compressed air into the cavity when the foamed resin material M is injected and filled.

It is a front view which shows the door trim of the upper and lower split structure using the door trim lower which is one Example of the foamed resin molded product which concerns on this invention. It is the II-II sectional view taken on the line in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is explanatory drawing which shows schematic structure of the shaping die for shape | molding the door trim lower in the door trim shown in FIG. It is a press chart figure of the movable side metal mold | die in the shaping die shown in FIG. It is explanatory drawing which shows the injection filling process of the foamed resin material in the molding method of the door trim lower which shape | molds a door trim lower using the shaping die shown in FIG. It is explanatory drawing which shows the retraction operation | movement of the movable side metal mold | die in the molding method of the door trim lower which shape | molds a door trim lower using the molding die shown in FIG. It is explanatory drawing which shows the foam molding process in the molding method of the door trim lower which shape | molds a door trim lower using the shaping die shown in FIG. It is sectional drawing which shows the modification of the door trim lower to which the foamed resin molded product which concerns on this invention is applied. It is sectional drawing which shows the modification of the door trim lower to which the foamed resin molded product which concerns on this invention is applied. It is a front view which shows the conventional door trim for motor vehicles. It is explanatory drawing which shows schematic structure of the shaping die used for the shaping | molding method of the conventional automotive door trim. It is a press chart figure of the movable side metal mold | die in the conventional door trim shaping | molding method. It is explanatory drawing which shows the shaping | molding process of the vertical wall part in the shaping | molding method of the conventional door trim. It is explanatory drawing which shows the malfunction in the shaping | molding method of the conventional door trim.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automotive door trim 20 Door trim upper 30 Door trim lower 30a Solid layer 30b Foamed layer 32 General part 33 Vertical wall part 34 Thin part 35 Sheet thickness gradual change part 40 Molding die 50 Movable side die 60 Fixed side die 61 Hot runner 62 Valve gate 63 Ejector pin 64 Step portion 65 Inclined surface 70 Injection machine C cavity C1 Vertical wall cavity M Foamed resin material

Claims (1)

After the foamed resin material (M) is injected and filled into the cavity (C) defined between the movable mold (50) and the fixed mold (60), the movable mold (50) is retracted. The foamed resin material (M) is foamed by securing the foaming space and then molded into a required shape, and the solid layer (30a) is formed on the outer surface. In the foamed resin molded product (30) having the foam layer (30b) in
A vertical wall portion (33) is provided at the entire peripheral edge of the foamed resin molded product (30) or a part of the peripheral edge, and a solid layer (30a) is provided at the tip of the vertical wall portion (33). A thin-walled portion (34) consisting of only a thin-walled portion (34) is set, and between the vertical wall portion (33) and the thin-walled portion (34), a plate thickness gradually changing portion (35) whose thickness changes gently is set , The inner surface of the plate thickness gradually changing portion (35) from the vertical wall portion (33) to the thin wall portion (34) is processed into a concave R surface (35a), and the ratio of the solid layer (30a) is set to be large. the resin foam product, characterized in that there.

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