JP2016083851A - Resin-molded article and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-molded article that achieves a cushioning capability while ensuring the strength and rigidity, and to provide a production method for resin-molded article.SOLUTION: The resin-molded article 10 includes a front surface wall 25A having a cushioning capability, a rear surface wall 25B having a rigidity and oppositely facing to the front surface wall 25A, a hard first core member 21 disposed between front surface wall 25A and rear surface wall 25B to wholly abut to the rear surface wall 25B, and a soft second core member 22 disposed so as at least a portion to be surrounded by the core member 21, and in which the first core member 21 is abutted to the front surface wall 25A in at least a portion of an outer edge part thereof and is integrally adhered.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin molded product and a method for producing a resin molded product.

  Conventionally, regarding a resin molded product, various techniques have been proposed for uses such as floor materials, tatami mats, wall boards, seat sheets, seat back boards, cushions, benches, and the like (for example, see Patent Document 1).

  Patent Document 1 proposes a stand chair in which a seat surface, a footrest surface, and a leg portion are integrally formed of a resin material. Generally, in this type of stand chair, the required strength is obtained by the hardness of the resin itself.

  Incidentally, in resin molded products such as a chair for a stand, in addition to strength and rigidity, a cushioning property may be desired. However, since the stand chair of Patent Document 1 simply obtains strength by the hardness of the resin itself, it does not have cushioning properties and cannot meet the above demand.

JP-A-10-14697

  This invention is made | formed in view of such a situation, The objective is providing the manufacturing method of the resin molded product which can obtain cushioning properties, ensuring strength and rigidity, and a resin molded product. It is in.

The present invention is grasped by the following composition.
(1) The present invention is a resin molded article, a front wall having cushioning properties, a rear wall facing the front wall and having rigidity, and the rear wall between the front wall and the rear wall. A hard first core material disposed so as to generally contact the first core material, and a soft second core material disposed so as to be at least partially surrounded by the first core material, The first core member is in contact with the surface wall at at least a part of an outer edge portion thereof, and is integrally bonded.

(2) In the configuration of (1), the present invention provides the second core in a range in which the first core material is in partial contact with the surface wall and the first core material is not in contact. The material is in contact with the surface wall.

(3) In the configuration of (2), the present invention is characterized in that the first core material is partially in contact with the surface wall at a plurality of locations.

(4) According to the present invention, in the configuration of (1), the first core material is composed of a pair of first core materials, and the second core material is sandwiched between the pair of first core materials. One of the pair of first core members is in contact with and adhered to the front wall as a whole, and the other of the pair of first core members is abutted against the back wall. It is characterized by being bonded in contact.

(5) The present invention is a method for producing a resin molded product, which is a hard first core material and a soft second material disposed so that at least a part of the outer periphery is surrounded by the first core material. The first resin sheet in the molten state and the molten state between the step (A) of preparing a core material made of the core material in advance and the first divided mold and the second divided mold constituting the molding die Arranging the second resin sheet (B), and sucking the first resin sheet and the second resin sheet into the first split mold and the second split mold, respectively, A step (C) of forming a front wall and a back wall in a shape along a molding surface of each of the first split mold and the second split mold; and the core material as the first split mold and the second split mold. A step (D) of clamping the molding die in a state of being arranged between the split die, and in the molding die The first core material is in contact with the surface wall so that the first core material is in general contact with the back wall and at least a part of the outer edge of the first core material. And the step (E) of cooling while sandwiched between the back wall and the surface wall, the core material, and the back wall are integrated, and the resin molded product cooled to a predetermined temperature or less is opened. And (F) removing from the molding die.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the resin molded product and the resin molded product which can obtain cushioning properties, ensuring intensity | strength and rigidity can be provided.

It is sectional drawing of the resin molded product which concerns on 1st Embodiment of this invention. It is sectional drawing of the resin molded product which concerns on 2nd Embodiment. It is sectional drawing of the resin molded product which concerns on 3rd Embodiment. It is a side view of the stand bench concerning a 4th embodiment. It is sectional drawing of the stand bench shown by FIG. It is a figure explaining the structure of the shaping | molding apparatus used for the manufacturing method of a resin molded product. It is explanatory drawing of the manufacturing method of a resin molded product, and is a figure which shows the state which extrudes a sheet | seat. It is explanatory drawing of the manufacturing method of a resin molded product, and is a figure which shows the state which forms the extruded sheet | seat in a predetermined shape. It is explanatory drawing of the manufacturing method of a resin molded product, and is a figure which shows the state which has arrange | positioned the core material to the shaping die. It is explanatory drawing of the manufacturing method of a resin molded product, and is a figure which shows the state which clamped the shaping die.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. The same number is attached | subjected to the same element through the whole description of embodiment.

(First embodiment)
First, the whole structure of the resin molded product according to the first embodiment will be described with reference to FIG.

  As shown in FIG. 1, the resin molded product 10 is sandwiched between a front wall 25A having cushioning properties, a back wall 25B having rigidity, facing the front wall 25A, and the front wall 25A and the back wall 25B. The sandwich panel structure includes a hard first core material 21 and a soft second core material 22. The planar shape of the resin molded product 10 can be selected from various shapes such as a square shape. The resin molded product 10 can be used for various panels that require cushioning, such as a stand bench installed on a stadium stand, a cushion, a seat, a flooring, a wall, and a tatami.

  The first core material 21 is a member having a predetermined compressive strength and shear strength from the viewpoint of expressing rigidity as a sandwich structure, and includes a flat base portion 21a provided on the back wall 25B side and an outer edge of the base portion 21a. And an annular standing wall 21b rising from the portion to the surface wall 25A side. The base 21a is integrated by being brought into contact with and welded to the back wall 25B as a whole. Further, the first core material 21 is in contact with the surface wall 25A at least at a part of its outer edge, and in this example, the annular end surface 21b1 of the standing wall 21b having two to four sides contacts the surface wall 25A. It is integrated by contact and welding.

  The first core material 21 is preferably, for example, a foam having a closed cell structure such as foamed polyolefin, a honeycomb structure, or the like. In particular, from the viewpoint of welding and fixing to the front wall 25A and the back wall 25B, the front wall 25A and the back wall A bead foam composed of expanded beads of the same material as the resin constituting 25B is preferred.

  The second core material 22 is a plate-like member having cushioning properties, and is arranged so that at least a part thereof is surrounded by the first core material 21. In this example, the outer peripheral shape of the second core material 22 is formed into a shape corresponding to the inner peripheral shape of the standing wall 21b of the first core material 21, and the second core material 22 is formed in the space surrounded by the standing wall 21b. Fit. Further, the surface 22a of the second core member 22 on the surface wall 25A side is located on substantially the same plane as the end surface 21b1 of the standing wall 21b. Thereby, the second core material 22 is in contact with the surface wall 25A in a range where the first core material 21 is not in contact (a range surrounded by the annular end surface 21b1). For the second core material 22, it is preferable to use, for example, a foam having an open cell structure such as urethane foam, a soft resin such as a fibrous body, or a resin structure having resilience.

  Most of the surface wall 25A forms the surface 25A1 of the resin molded product 10. Further, the surface wall 25A has a peripheral wall 25A2 that is bent from the outer periphery of the surface 25A1 along the outer peripheral surface of the first core material 21 (in this example, the outer peripheral surface of the standing wall 21b). A space portion is provided between the outer peripheral surface of the first core material 21 and the surface wall 25A from the viewpoint of improving moldability, and is in contact with and welded to obtain rigidity as a sandwich structure. There is no need.

  The surface wall 25A is made of a thin sheet and / or a soft material, and does not hinder the cushioning property of the second core material 22, and the second core material is made through the surface wall 25A. Can transmit cushioning properties. The surface wall 25A is preferably a sheet formed of a soft resin. As the constituent material of the surface wall 25A, for example, polyolefin, thermoplastic elastomer (polyethylene elastomer, polystyrene elastomer, soft urethane, soft vinyl chloride resin) or the like can be used, and talc or glass fiber is used to increase the strength. Inorganic fillers such as, weathering agents and antioxidants may be added to increase weather resistance. In addition, a decorative sheet or the like can be attached to the surface wall 25A in order to improve design properties and weather resistance.

  The back wall 25B is bonded to the first core material 21 by welding, an adhesive, or the like, and most of the back wall 25B forms the back surface 25B1 of the resin molded product 10. Further, the back wall 25B has a peripheral wall 25B2 that bends from the outer periphery of the back surface 25B1 along the outer peripheral surface of the first core material 21 (in this example, the outer peripheral surface of the base portion 21a). Similarly, a space is provided between the outer peripheral surface of the first core member 21 and the back wall 25B. End portions 25A3 and 25B3 of the peripheral wall 25A2 and the peripheral wall 25B2 are welded on the outer periphery of the resin molded product 10.

  The back wall 25B is composed of a sheet and / or a hard material formed thicker than the front wall 25A, and has rigidity. The back wall 25B is preferably a sheet formed of a hard resin. As the constituent material of the back wall 25B, high-density polyethylene, polyolefin such as polypropylene, amorphous resin such as ABS resin, etc. can be used. Furthermore, inorganic fillers such as talc and glass fiber, weather resistance, etc. are used to increase the strength. In order to improve the properties, a weathering agent, an antioxidant and the like may be added.

  The material and thickness of each of the front wall 25A and the back wall 25B can be arbitrarily set as long as the required cushioning property is obtained on the front wall 25A side and the required strength is obtained on the back wall 25B side. It is. For example, even when the same material is used for the front wall 25A and the back wall 25B, the front wall 25A is made thinner so that the front wall 25A has cushioning properties, and the back wall 25B is more than the front wall 25A. It is possible to give strength to the back wall 25B side and to obtain high rigidity as a whole resin molded product. Further, even when the front wall 25A and the back wall 25B have the same thickness, the front wall 25A is made of a soft material so that the front wall 25A has cushioning properties. By forming it with a hard material, it is possible to give strength to the back wall 25B side.

  In the resin molded product 10 configured as described above, a sandwich structure including the front wall 25A, the back wall 25B, and the first core material 21 that is surface-bonded to each of the front wall 25A and the rear wall 25B is configured. Furthermore, the soft second core material 22 is fitted inside the upright wall 21b so as to be integrally provided, thereby obtaining the resin molded product 10 having sufficient strength and rigidity as a whole and having cushioning properties on the surface 25A1 side. be able to.

  On the other hand, if no standing wall is provided, that is, if a simple plate-like hard core material is placed on the back wall side with a cushion material of the same size as this, the back wall side in the resin molded product However, since the compressive strain is easily generated on the entire surface wall side by the soft core material serving as a cushion material, high rigidity as a sandwich structure cannot be obtained. In this case, sufficient rigidity is not ensured as a whole resin molded product.

  In this regard, in the resin molded product 10, at least a part of the first core material 21 (the end surface 21b1 of the standing wall 21b formed on the two to four sides of the outer edge of the first core material) is used as the surface wall 25A. Since they are brought into contact with each other, the distance between the front wall 25A and the back wall 25B, that is, the bulk (thickness) of the first core material 21 can be secured. Therefore, in the present embodiment, in the vicinity of the outer periphery of the resin molded product 10, the effective thickness for obtaining rigidity is approximately the same as the total thickness of the resin molded product 10, so that sufficient strength and rigidity can be obtained.

  Moreover, according to the resin molded product 10, the gap 26 is formed between the peripheral walls 25A2 and 25B2 and the outer peripheral surface of the first core material 21, and thus the peripheral walls 25A2 and 25B2 after molding and the first core are formed. The resin molded product 10 is prevented from being deformed by the difference in thermal shrinkage with the material 21.

(Second Embodiment)
Next, the resin molded product of 2nd Embodiment is demonstrated based on FIG. In addition, the same code | symbol is attached | subjected to the element which is common in the resin molded product 10 (refer FIG. 1) mentioned above, and the overlapping description is abbreviate | omitted (same also about 3rd and 4th embodiment mentioned later).

  As shown in FIG. 2, in the resin molded product 30 of the second embodiment, the first core material 21 is partially brought into contact with the surface wall 25A at a plurality of locations. Here, the partition wall 32 is formed in the space inside the standing wall 21 b of the first core material 21, and the second core material 22 is fitted into each space section partitioned by the partition wall 32. In addition to the end surface 21b1 of the standing wall 21b, the end surface 32a of the partition wall 32 is also brought into contact with and welded to the surface wall 25A. Further, the surface 22a on the surface wall 25A side of each second core member 22 is located on substantially the same plane as the end surface 21b1 of the standing wall 21b.

  According to the resin molded product 30 of the second embodiment, the bulk (thickness) of the first core material 21 can be secured by the partition wall 32 even in a portion other than the standing wall 21b, and the center of the resin molded product 30 can be secured. Rigidity can also be obtained on the part side. In addition, a plurality of portions having cushioning properties can be set in the resin molded product 30 by arranging the plurality of second core members 22.

(Third embodiment)
Next, the resin molded product of 3rd Embodiment is demonstrated based on FIG.
As shown in FIG. 3, in the resin molded product 80 of the third embodiment, the first core material 21 is made up of a plurality of divided bodies (here, a pair of rear side divided bodies 82 and front side divided bodies 83). 1st core material), and the 2nd core material 22 is clamped by these some division bodies. The surface side divided body 83 is preferably configured to be thinner than the back side divided body 82 in order to develop cushioning properties on the surface wall 25A side.

  The rear surface side divided body 82 is provided along the rear surface wall 25B, and a base portion 82a that is entirely in contact with the rear surface wall 25B, an annular vertical wall 82b that rises from the outer periphery of the base portion 82a toward the front surface wall 25A, and the vertical wall And a convex concave portion 82c provided on the annular end surface 82b1 of 82b.

  The front surface side divided body 83 is provided along the front surface wall 25A, and has a base portion 83a that abuts the entire surface wall 25A, and an annular standing wall 83b that is formed from the outer periphery of the base portion 83a toward the back wall 25B side. And an uneven portion 83c provided on the annular end surface 83b1 of the standing wall 83b. The concavo-convex portion 83 c of the front surface side divided body 83 is formed in a shape that meshes with the convex concave portion 82 c of the back surface side divided body 82.

  The soft second core material 22 is accommodated in the space surrounded by the upper and lower two standing walls 82b and 83b in a state where the convex and concave portions 82c and the concave and convex portions 83c are engaged with each other. Thereby, the second core material 22 is surrounded by the first core material 21 on the entire surface thereof.

  According to the resin molded product 30 of the third embodiment, the bulk (thickness) of the first core material 21 is secured by the upper and lower two standing walls 82b and 83b, and high rigidity is obtained. Is brought into contact with and welded to the entire surface of the surface wall 25A, so that an appropriate rigidity can be obtained even on the surface 25A1 of the surface wall 25A (for example, the seating surface of the bench).

(Fourth embodiment)
Next, the resin molded product of 4th Embodiment is demonstrated based on FIG. 4, FIG.
As shown in FIG. 4, in the fourth embodiment, the resin molded product of the present invention is applied to a folding stand bench, and this stand bench 90 is a resin molded product 91 constituting a member on the seating surface side. And a resin molded product 92 constituting a member on the backrest side, and a hinge portion 93 is provided between the resin molded products 91 and 92.

  As shown in FIG. 5, each of the resin molded products 91 and 92 has a sandwich structure in which the resin molded products 10, 30, and 80 of the first to third embodiments described above are the basic components. In this example, each of the resin molded products 91 and 92 is configured by a sandwich structure having the above-described resin molded product 10 (see FIG. 1) as a basic configuration. Further, in the molding die for forming the resin molded products 91 and 92, the resin molded products 91 and 92 and the hinge portion 93 are integrated by integrally forming the hinge portion 93 between the resin molded products 91 and 92. A stand bench 90 is formed. The hinge part 93 has at least one or more thin-walled parts 93a by compression molding, is formed to be bendable, and connects the resin molded product 91 to the resin molded product 92 so as to be rotatable.

  According to the fourth embodiment, in each of the resin molded product 91 on the seat surface side and the resin molded product 92 on the backrest side, the bulk (thickness) of the first core material 21 is ensured and the strength and rigidity are obtained. At the same time, it is possible to provide an integrally molded product of the folding stand bench 90 in which cushioning properties can be obtained by the soft second core material 22.

  On the other hand, it is also possible to form the resin molded products 91 and 92 individually and to connect the resin molded products 91 and 92 with separate hinges. However, in this case, three or more components of the stand bench are required.

  In this respect, since the stand bench 90 can be constituted by one molded product integrally including the resin molded products 91 and 92 and the hinge portion 93, the number of parts can be compared with the case where the resin molded products 91 and 92 are individually formed. The manufacturing man-hours and assembly man-hours can be greatly reduced.

(Production method of resin molded products)
Next, the manufacturing method of a resin molded product is demonstrated based on FIGS. Here, a manufacturing method in the case of manufacturing the resin molded product 10 (see FIG. 1) will be described.

(Configuration of molding apparatus 40)
Prior to description of specific steps of the manufacturing method (steps (A) to (F) to be described later), a molding apparatus 40 used in the manufacturing method will be described with reference to FIG.

  As shown in FIG. 6, the molding apparatus 40 includes first and second extrusion apparatuses 42A and 42B, and a mold clamping apparatus 43 disposed below the first and second extrusion apparatuses 42A and 42B. Prepare. In the molding apparatus 40, the molten first and second resin sheets 41A and 41B made of the thermoplastic resin extruded from the first and second extrusion apparatuses 42A and 42B are sent to the mold clamping apparatus 43, and the mold clamping is performed. The first and second resin sheets 41A and 41B in a molten state are formed into a predetermined shape by the device 43.

  In addition, since the 1st extrusion apparatus 42A and the 2nd extrusion apparatus 42B are the same, in the following description, only the 1st extrusion apparatus 42A corresponding to the 1st resin sheet 41A is demonstrated, and the 2nd Description of the second extrusion device 42B corresponding to the resin sheet 41B is omitted. Further, in the molding apparatus 40, “A” is followed by the symbol of the element corresponding to the first resin sheet 41A, and “B” is followed by the symbol of the element corresponding to the second resin sheet 41B.

  The first extruding device 42A is a well-known extruding device and will not be described in detail. However, a cylinder 46A provided with a hopper 45A, a screw (not shown) provided in the cylinder 46A, and a screw The hydraulic motor 47A is connected, an accumulator 48A is connected to the cylinder 46A, and a plunger 51A is provided in the accumulator 48A. In the first extrusion device 42A, the resin pellets introduced from the hopper 45A are melted and kneaded by rotation of the screw by the hydraulic motor 47A in the cylinder 46A, and the molten resin is transferred to the accumulator 48A and stored in a certain amount. Then, the molten resin in the accumulator 48A is sent to the T die 52A by driving the plunger 51A, and is extruded as a continuous first resin sheet 41A having a predetermined length through the extrusion slit 53A. The extruded first resin sheet 41A is sent downward while being clamped by a pair of rollers 55A arranged at intervals, and is suspended between first and second split dies 57A and 57B (described later). Accordingly, the first resin sheet 41A is disposed between the first and second split dies 57A and 57B in a state having a uniform thickness in the vertical direction (extrusion direction).

The extrusion capability of the first extrusion device 42A is appropriately determined from the viewpoint of the size of the first resin sheet 41A, the draw-down of the first resin sheet 41A, or the prevention of neck-in occurrence. More specifically, from a practical point of view, the extrusion rate of one shot in intermittent extrusion is preferably 1 to 10 kg, and the extrusion rate of the resin from the extrusion slit 53A is several hundred kg / hour or more, more preferably 700 kg / hour or more. In addition, from the viewpoint of preventing the first resin sheet 41A from being drawn down or necking in, the extrusion process of the first resin sheet 41A is preferably as short as possible and depends on the type of resin, the MFR value, and the melt tension value. However, in general, the extrusion process should be completed within 40 seconds, more preferably within 10-20 seconds. For this reason, the extrusion area per unit time and unit time from the extrusion slit 53A of the thermoplastic resin is 50 kg / hour / cm ² or more, more preferably 150 kg / hour / cm ² or more.

  The first resin sheet 41A can be stretched and thinned by feeding the first resin sheet 41A sandwiched between the pair of rollers 55A downward. By adjusting the relationship between the extrusion speed of the extruded first resin sheet 41A and the delivery speed of the first resin sheet 41A by the pair of rollers 55A, it is possible to prevent the occurrence of drawdown or neck-in. Therefore, the restriction on the type of resin, particularly the MFR value and melt tension value, or the extrusion amount per unit time can be reduced.

  The extrusion slit 53A provided in the T die 52A is arranged vertically downward, and the first resin sheet 41A pushed out from the extrusion slit 53A is sent from the extrusion slit 53A as it is and is sent vertically downward. ing. The extrusion slit 53A can change the thickness of the first resin sheet 41A by making the interval variable.

  The pair of rollers 55A is arranged below the extrusion slit 53A in a state in which the respective rotation axes are substantially horizontal and are arranged in parallel to each other. One of the pair of rollers 55A is a rotation driving roller, and the other is a rotation driven roller. More specifically, the pair of rollers 55A is arranged so as to be line-symmetric with respect to the first resin sheet 41A extruded in a form that hangs downward from the extrusion slit 53A.

  The diameter of the roller 55A and the axial length of the roller 55A are the extrusion speed of the first resin sheet 41A to be formed, the length of the first resin sheet 41A in the extrusion direction, the width of the first resin sheet 41A, the resin It is set as appropriate according to the type. However, from the viewpoint of smoothly feeding the first resin sheet 41A downward by the rotation of the roller 55A with the first resin sheet 41A sandwiched between the pair of rollers 55A, the diameter of the rotation driving roller is driven to rotate. It is preferable to set it slightly larger than the diameter of the roller. In addition, if the curvature of the roller 55A is too large or too small, there is a problem that the first resin sheet 41A is wound around the roller 55A. Therefore, the diameter of the roller 55A is preferably in the range of 50 to 300 mm.

  On the other hand, the mold clamping device 43 is a well-known mold clamping device and has a mold driving device (not shown) and a molding die 56, although detailed explanation thereof is omitted. The molding die 56 is a divided type, and includes a first split die 57A and a second split die 57B that fits the first split die 57A. The first and second split dies 57A and 57B are arranged with their molding surfaces 58A and 58B facing each other, and the molding surfaces 58A and 58B are arranged along a substantially vertical direction.

  The mold driving device is a device that moves the first and second split dies 57A and 57B in a direction substantially perpendicular to the supply direction of the molten first and second resin sheets 41A and 41B. 1. The second split molds 57A and 57B are moved between the open position and the closed position.

  A first annular pinch-off portion 61A and a second annular pinch-off portion 61B are formed around the molding surfaces 58A and 58B of the first and second split dies 57A and 57B, respectively. The first and second annular pinch-off portions 61A and 61B are formed in an annular shape so as to surround the molding surfaces 58A and 58B, and project toward the opposed first and second split dies 57A and 57B. Thus, when the first and second split dies 57A and 57B are clamped, the tip portions of the first and second annular pinch-off portions 61A and 61B come into contact with each other.

  Form frames 62A and 62B are slidably fitted in close contact with the outer peripheral portions of the first and second split dies 57A and 57B. The molds 62A and 62B can be moved relative to the first and second split molds 57A and 57B by a mold moving device (not shown). More specifically, the molds 62A and 62B protrude inward from the first and second split molds 57A and 57B, thereby being arranged between the first and second split molds 57A and 57B. 1. It can contact the outer surfaces 63A and 63B of the second resin sheets 41A and 41B.

  The first and second split dies 57A and 57B are respectively driven by a mold driving device, and in the open position, the first and second resin sheets 41A and 41B are interposed between the first and second split dies 57A and 57B. In the closed position, the first and second annular pinch-off portions 61A and 61B of the first and second split molds 57A and 57B are brought into contact with each other in the closed position, whereby the first and second split molds 57A are disposed. , 57B are formed with sealed spaces 67A, 67B (see FIG. 4). The closed position is set to a substantially intermediate position between the first and second resin sheets 41A and 41B (a position approximately equidistant from the first and second resin sheets 41A and 41B). The first extrusion device 42A and the pair of rollers 55A, and the second extrusion device 42B and the pair of rollers 55B are arranged symmetrically with respect to the closed position.

  Further, vacuum suction chambers 65A and 65B are provided in the first and second split dies 57A and 57B, respectively. The vacuum suction chambers 65A and 65B communicate with the molding surfaces 58A and 58B through the suction holes 66A and 66B. By suctioning from the vacuum suction chambers 65A and 65B through the suction holes 66A and 66B, the first The second resin sheets 41A and 41B are adsorbed on the molding surfaces 58A and 58B. Thus, the first and second resin sheets 41A and 41B are shaped into shapes along the surfaces of the molding surfaces 58A and 58B.

(Process (A))
In the step (A), a core material 11 (see FIG. 1) composed of a hard first core material 21 and a soft second core material 22 disposed so as to be at least partially surrounded by the first core material 21. 1) is prepared in advance. The second core material 22 can be bonded to the first core material 21 with an adhesive or an adhesive tape.

(Process (B))
In the step (B), as shown in FIG. 6, first, a predetermined amount of the melt-kneaded thermoplastic resin is stored in the accumulators 48A, 48B, and the extrusion slits 53A, 53A, 52B provided in the T dies 52A, 52B are provided. From 53B, the stored thermoplastic resin is intermittently extruded at a predetermined extrusion rate per unit time. Thereby, the thermoplastic resin swells and hangs downward in a molten sheet shape, and is extruded at a predetermined extrusion speed with a predetermined thickness. Next, the rollers 55A and 55B were moved to the open position, and the distance between the pair of rollers 55A and the distance between the pair of rollers 55B were increased below the thickness of the first and second resin sheets 41A and 41B, and the rollers 55A and 55B were pushed downward. The lowermost portions of the melted first and second resin sheets 41A and 41B are smoothly supplied between the pair of rollers 55A and the pair of rollers 55B. In addition, the timing which makes the space | interval of a pair of rollers 55A and the space | interval of a pair of roller 55B larger than the thickness of 1st, 2nd resin sheet 41A, 41B is not after an extrusion start, and secondary shaping | molding was complete | finished for every one shot It may be done at the time. Next, the pair of rollers 55A and the pair of rollers 55B are moved closer to each other and moved to the closed position, the first and second resin sheets 41A and 41B are sandwiched, and the first and second rollers 55A and 55B are rotated to rotate the first and second. The resin sheets 41A and 41B are sent out downward.

  Further, the first and second resin sheets 41A and 41B formed to have a uniform thickness in the extrusion direction are disposed between the first and second split dies 57A and 57B. At this time, the first and second resin sheets 41 </ b> A and 41 </ b> B are positioned in a form that protrudes from around the first and second annular pinch-off portions 61 </ b> A and 61 </ b> B. As described above, the first and second resin sheets 41A and 41B, which are the materials of the front wall 25A and the back wall 25B (see FIG. 1), are spaced apart from each other. It arrange | positions between split type | molds 57A and 57B. Note that the first and second split molds can be obtained by individually adjusting the interval between the extrusion slits 53A and 53B or the rotation speed of the rollers 55A and 55B with respect to the first and second resin sheets 41A and 41B, respectively. The thicknesses of the first and second resin sheets 41A and 41B disposed between 57A and 57B can be individually adjusted.

  In this example, the first resin sheet 41A corresponding to the thin front wall 25A (see FIG. 1) is formed thin, and the second resin sheet 41B corresponding to the thick back wall 25B (see FIG. 1) is thick. The distance between the extrusion slits 53A and 53B or the rotation speed of the rollers 55A and 55B is adjusted so as to be formed.

  Next, as shown in FIG. 7, the molds 62A and 62B are moved from the first and second split molds 57A and 57B until they contact the outer surfaces 63A and 63B of the first and second resin sheets 41A and 41B. Then, sealed spaces 67A and 67B surrounded by the molding surfaces 58A and 58B, the inner peripheral surfaces of the molds 62A and 62B, and the outer surfaces 63A and 63B of the first and second resin sheets 41A and 41B are formed.

(Process (C))
In step (C), as shown in FIG. 8, the first and second sealed spaces 67A and 67B (see FIG. 5) are sucked through the suction holes 66A and 66B communicating with the vacuum suction chambers 65A and 65B. The second resin sheets 41A and 41B are pressed against the molding surfaces 58A and 58B to form the first and second resin sheets 41A and 41B in a shape along the surfaces of the molding surfaces 58A and 58B. Thereby, the front wall 25A and the back wall 25B are formed.

(Process (D))
In the step (D), as shown in FIG. 9, the core material 11 formed in a predetermined shape is placed between the front wall 25A and the back wall 25B (between the first and second resin sheets 41A and 41B). Deploy. Here, as a means for arranging the core material 11 between the front wall 25A and the back wall 25B, for example, a well-known adsorption manipulator can be used. That is, after the core material 11 is pressed and held against one of the front wall 25A and the back wall 25B by the suction type manipulator, the suction type manipulator is detached from the core material 11 and the first and second split dies 57A and 57B are removed. Try to pull it out.

  Then, while sucking and holding the first and second resin sheets 41A and 41B, the first and second split molds 57A and 57B are held until the first and second annular pinch-off portions 61A and 61B come into contact with each other. The first and second split molds 57A and 57B are clamped by moving them toward each other. That is, the first resin sheet 41A and the core material are formed by the first split mold 57A disposed outside the first resin sheet 41A and the second split mold 57B disposed outside the second resin sheet 41B. 11 and the second resin sheet 41B are sandwiched.

(Process (E))
In the step (E), as shown in FIG. 10, the back wall 25 </ b> B and the front wall 25 </ b> A are welded to the first core material 21 in the clamped molding die 56, and the first and second annular shapes are welded. When the pinch-off portions 61A and 61B are brought into contact with each other, the end 25B3 of the back wall 25B and the end 25A3 of the front wall 25A are welded and integrated and cooled. As a result, a molded body 71 in which the entire core material 11 is covered with the front wall 25A and the back wall 25B is formed.

(Process (F))
In the step (F), the front wall 25A, the core material 11 and the back wall 25B are integrated, and the molded body 71 cooled to a predetermined temperature or lower is opened from the first and second divided dies 57A and 57B. The burrs 73 on the outside of the first and second annular pinch-off portions 61A and 61B are cut out. Thereby, the resin molded product 10 (refer FIG. 1) is obtained.

  By repeating the above steps (A) to (F), the resin molded product 10 can be manufactured one after another.

(Other manufacturing methods for resin molded products)
In the manufacturing method described above, the core material 11 (see FIG. 1) is used, but the configuration of the core material disposed between the front wall 25A and the back wall 25B is arbitrary. For example, it replaces with the core material 11 (refer FIG. 1), and is using the core material 31 (refer FIG. 2) and the core material 81 (refer FIG. 3), and is the same as the process (B)-process (F) mentioned above. In a manner, the resin molded product 30 (see FIG. 2) and the resin molded product 80 (see FIG. 3) can be obtained.

  The effects of the resin molded products 10, 30, 80, stand bench 90, and resin molded product manufacturing method described above will be described.

  According to the resin molded products 10, 30, 80, the stand bench 90, and the resin molded product manufacturing method, the soft second core material 22 and the soft surface wall 25A provide cushioning properties, and at the same time bulk (thickness). The required strength is also obtained by the hard first core material 21 and the hard back wall 25B. As a result, in the resin molded products 10, 30, 80, and the stand bench 90, cushioning properties can be obtained while ensuring strength and rigidity.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. Further, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  For example, in the embodiment, an example in which a sheet is extruded from a T die and a resin molded product is manufactured using a split mold has been described. However, the method of manufacturing the resin molded product of the present invention is not particularly limited thereto. Alternatively, a cylindrical parison may be extruded and divided into two sheets before or immediately after extrusion, and a resin molded product may be manufactured using the two sheets thus divided. Alternatively, instead of using the two molten sheets extruded from the T-die directly for molding, the raw sheets of the two sheets prepared in advance are preheated before molding, The method for producing the resin molded product of the present invention can be selected from various methods, such as using a molding technique (so-called twin composite molding) for producing a resin molded product using a plurality of divided molds arranged in the direction.

DESCRIPTION OF SYMBOLS 10 Resin molded product 11 Core material 21 1st core material 22 2nd core material 25A Front wall 25B Back wall 30 Resin molded product 31 Core material 80 Resin molded product 81 Core material 91 Resin molded product 92 Resin molded product 40 Molding apparatus 41A First resin sheet 41B Second resin sheet 56 Molding mold 57A First split mold 57B Second split mold

Claims (5)

A resin molded product,
A surface wall having cushioning properties;
A back wall facing the front wall and having rigidity;
A hard first core material disposed between the front wall and the back wall so as to be entirely in contact with the back wall;
A soft second core material disposed so as to be at least partially surrounded by the first core material;
The resin molded product, wherein the first core material is in contact with the surface wall at at least a part of an outer edge thereof and is integrally bonded.   The first core material is partially in contact with the surface wall, and the second core material is in contact with the surface wall in a range where the first core material is not in contact. The resin molded product according to claim 1.   The resin molded product according to claim 2, wherein the first core material is in partial contact with the surface wall at a plurality of locations.   The first core material is composed of a pair of first core materials, the second core material is sandwiched between the pair of first core materials, and one of the pair of first core materials is 2. The apparatus according to claim 1, wherein the entire surface wall is in contact with and adhered to the front wall, and the other of the pair of first core members is in contact with and adhered to the back wall in general. The resin molded product described. A method for producing a resin molded product, comprising:
A step (A) of preparing in advance a core material made of a hard first core material and a soft second core material arranged so as to be at least partially surrounded by the first core material;
A step (B) of disposing a molten first resin sheet and a molten second resin sheet between a first divided mold and a second divided mold constituting the molding die;
Each of the first resin sheet and the second resin sheet is sucked into the first split mold and the second split mold, and each of the first split mold and the second split mold is molded. Forming a front wall and a back wall in a shape along the surface (C);
A step (D) of clamping the molding die in a state where the core material is disposed between the first split mold and the second split mold;
In the molding die, the first core material is in contact with the back wall as a whole, and the first core material is in contact with the surface wall at least at a part of the outer edge portion of the first core material. A step (E) of cooling the core material between the front wall and the back wall;
A step (F) in which the surface wall, the core material, and the back wall are integrated and a resin molded product cooled to a predetermined temperature or less is removed from the mold that has been opened. A method for manufacturing a resin molded product.

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