JP2017119380A - Manufacturing method for resin molded article and manufacturing mold for resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a resin molded article capable of suppressing generation of thin wall of a side wall portion or the like and molding failure of a pinhole or the like when molding a resin molded article having a cross section with a U-shape and a manufacturing mold for a resin molded article.SOLUTION: There can be provided a manufacturing method of a resin molded article suppressing generations of thin wall, pinhole, or the like by making wall thickness of a side wall uniform because an outer side of a pinch off part 81 in a side wall formation part 51a of a male mold 41 has a specific shape, such as a flat part 61 or a male inclined plane part 62, when a resin molded article having a cross section with a U-shape is formed by forming a sheet-like resin with a melting state to shapes of a core 43 of the male mold 41 and a cavity of a female mold respectively by using vacuum suction or the like at secondary forming, then mold closing the male mold 41 and the female mold and laminating the sheet-like resin so that peripheral parts of the sheet-like resin are deposited each other.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a method for producing a resin molded product and a mold for producing a resin molded product. More specifically, the present invention relates to a method for manufacturing a resin molded product having a U-shaped cross section, which requires deep drawing during molding, and a mold for manufacturing the resin molded product.

  In order to obtain a shape that requires deep drawing at the time of molding, for example, a U-shaped (including substantially U-shaped) cross-section with a hollow portion inside, conventionally, a blow-extrusion die head is used as a cylinder. In some cases, a blow molding method is used in which a hollow sheet product is obtained by gas blowing by sandwiching a molten sheet-like resin extruded into a shape (becomes a parison) between a pair of split molds (for example, patent literature) 1).

  In the blow molding method for producing a resin molded product having a shape that requires deep drawing, the part of the parison that contacts the mold maintains the thickness at the point of contact, and the part that is not in contact is stretched. However, since it is in contact with the mold, the deeply drawn portion finally contacting the mold is most thinned, which causes molding defects such as pin poles. In particular, in the case of a molded product having a U-shaped cross section and a box shape, the corner (corner) is most easily thinned. On the other hand, if the corners of such a box-shaped molded product are thinned, the product strength will be insufficient, and if the overall thickness of the molded product is increased to compensate for this, the weight will become too large and the cost will be increased. I was invited.

  Also, when molding molded products that require a U-shaped deep drawing by blow molding, many vacuum holes are arranged in the cavity and molding is performed using pre-blow, but when a hollow part is formed inside In that case, on the side wall side, defects (shearing) due to contact between the front and back meats occurred, and there was a problem that a good molded product could not be obtained.

  In recent years, in place of the blow molding method described above, a sheet-shaped resin in a molten state having an extrusion device and a mold clamping device disposed under the extrusion device and provided with a split mold (extruded from the extrusion device) There is provided a molding method in which a parison is sent to a mold clamping device, and a molten sheet-like resin is molded by the mold clamping device (see, for example, Patent Document 2). According to this molding method, the thermoplastic resin is intermittently extruded as a melted sheet-like resin by extrusion molding of primary molding, and the two sheet-like resins extruded by using vacuum suction or the like in secondary molding. By clamping the mold after forming it into the shape of the mold, the sheet-shaped resin is bonded so that the peripheral portions of the two sheet-shaped resins are welded to each other by joining the pinch-off portions of the divided molds. Is. In the molding method disclosed in Patent Document 2, the movable mold is disposed so as to surround the mold, and the sheet-shaped resin is moved to the movable mold so that the sheet-shaped resin is held in close contact with the movable mold. In this state, the movable mold frame is moved back to the mold side, the sheet resin is brought into contact with the male core and the female cavity, and the sheet resin is shaped into the shape of the male core. ing.

JP-A-9-76335 International Publication No. 2009/157197

  In the molding method disclosed in Patent Document 2, the sheet-shaped resin (parison) is drawn into the cavity in advance by evacuation, so that the occurrence of shirring, which is a problem in the blow molding method, is eliminated. The problem of thinning or pinholes has remained, and improvement has been demanded.

  In particular, when moving the sheet-shaped resin to the mold side using the movable mold as described above and shaping the sheet-shaped resin into the shape of the male core by vacuum suction or the like, the movement is performed. After the sheet-like resin attracted to the male mold side by the mold frame comes into contact with the male core, the sheet-shaped resin is attracted to both the side wall forming part of the core and the movable mold frame side. Or pinholes would occur.

  The present invention has been made in view of the above problems, and when forming a resin molded product having a U-shaped cross section that requires deep drawing at the time of molding, molding a thin wall, a pinhole, etc. An object of the present invention is to provide a method for producing a resin molded product capable of suppressing the occurrence of defects and a mold for producing the resin molded product.

  In order to solve the above problems, a method for producing a resin molded product according to the present invention includes a pair of side walls that are spaced apart from each other, and a connecting wall that connects end portions of the side walls, and has a hollow portion inside. A method for producing a resin molded product having a U-shaped cross section, in which two melted sheet-like resins, which are formed into a sheet from a melt-kneaded thermoplastic resin, are present on the lower side, and a side wall forming portion And a first step of disposing the male mold having a convex core having a connecting wall forming portion and a female die having a concave cavity having a side wall forming portion and a connecting wall forming portion, the two sheets One of the sheet-shaped resins close to the male mold is shaped into the shape of the core of the male mold using vacuum suction, and the female mold of the two sheet-shaped resins is molded into the female mold. Using a vacuum suction, close one piece of the cavity on the female mold. A second step of forming the first and second molds, and clamping the male and female molds together to bond the two sheet-shaped resins together so as to weld the peripheral edges of the two sheet-shaped resins. When forming a U-shaped resin molded product by a process, the outer side of the pinch-off part of the side wall forming part of the male mold has a flat shape toward the outer side of the male mold. The flat part and the male inclined surface part which becomes the inclination which becomes high toward the outward of the male type | mold from the said flat part are formed continuously over the longitudinal direction of the said side wall formation part, It is characterized by the above-mentioned.

  The method for producing a resin molded product according to the present invention is characterized in that, in the above-described present invention, the flat portion has a width of 15 mm or more, and the male inclined surface portion has an inclination angle of 20 ° to 80 °.

  The method for producing a resin molded product according to the present invention is characterized in that, in the above-described present invention, the vacuum suction is performed at least one of the periphery of the pinch-off portion and the flat portion in the side wall forming portion.

  The method for producing a resin molded product according to the present invention is the above-described present invention, in the above-described present invention, when molding the resin molded product having a U-shaped cross section in which the core material is disposed in the portion where the hollow portion is formed, After the second step, the core material is welded to at least one of the shaped sheet-like resins, and the third step is performed.

  The mold for producing a resin molded product according to the present invention includes a pair of side walls that are spaced apart from each other and a connecting wall that connects end portions of the side walls, and has a hollow portion inside, and has a U-shaped cross section. A mold for manufacturing a resin molded product, which has a convex core provided with a side wall forming portion and a connecting wall forming portion, outside the pinch-off portion in the side wall forming portion, outside the male die On the other hand, a flat portion having a flat shape and a male inclined surface portion having an inclination increasing from the flat portion toward the outside of the male die are continuously formed over the longitudinal direction of the side wall forming portion. It is characterized by that.

  The mold for producing a resin molded product according to the present invention is characterized in that, in the above-described present invention, the flat portion has a width of 15 mm or more, and the male inclined surface portion has an inclination angle of 20 ° to 80 °.

  In the mold for producing a resin molded product according to the present invention, in the above-described present invention, the suction part for performing vacuum suction is formed around at least one of the pinch-off part and the flat part in the side wall forming part. It is characterized by that.

  According to the present invention, the molten sheet-like resin is shaped into the respective shapes of the male core and the female cavity by using vacuum suction in secondary molding, and then the male mold and the female mold are clamped. When the sheet-shaped resin is bonded so that the peripheral portions of the sheet-shaped resin are welded together to form a resin molded product having a U-shaped cross section, the outer side of the pinch-off portion in the male side wall forming portion Since the side has a specific shape, it is possible to provide a method for manufacturing a resin molded product that equalizes the thickness of the side wall and suppresses the occurrence of thin portions or pinholes in the side wall, and a mold for manufacturing the resin molded product. it can.

It is the schematic which showed the one aspect | mode of the resin molded product of the shaping | molding object. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is the figure which showed the other aspect (mode in which the core material is arrange | positioned) of FIG. It is the figure which showed the other aspect (mode in which the core material is arrange | positioned) of FIG. It is the schematic which showed the one aspect | mode of the shaping | molding apparatus. In FIG. 6, it is the figure which showed the state cut | disconnected in the direction orthogonal to the drooping direction of sheet-like resin. It is the schematic (figure seen from the surface facing sheet-like resin) which showed the one aspect | mode of the structure of a male type | mold. It is CC sectional drawing of FIG. It is DD sectional drawing of FIG. It is the schematic (figure seen from the surface facing sheet-like resin) which showed the one aspect | mode of the structure of a female type | mold. It is EE sectional drawing of FIG. It is FF sectional drawing of FIG. It is the schematic which showed the female type | mold inclined surface part and its periphery. It is the figure which showed the cross-sectional structure of a female type | mold inclined surface part and its periphery. It is the figure which showed the state which made the movable mold | frame etc. contact | abut to sheet-like resin. It is the schematic which showed the state by which sheet-like resin was shaped to the metal mold | die. It is the schematic which showed the state which clamped. It is the figure which showed the state which inserted the core material between the metal mold | dies. In 2nd Embodiment, it is the schematic which showed the state by which sheet-like resin was shaped to the metal mold | die. In 2nd Embodiment, it is the schematic which showed the state clamped.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In the present invention, “manufacturing method” and “molding method” can be regarded as the same.

(A) About the shape of the resin molded product 1 to be molded:
First, the shape of the resin molded product 1 molded by the molding method of the resin molded product 1 according to the present invention (hereinafter sometimes simply referred to as “molding method”) will be described with reference to FIGS. 1 to 5. .

  1 is a schematic view showing an embodiment of a resin molded product 1 to be molded, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along the line BB in FIG. The figure which showed the other aspect (mode in which the core material 17 is arrange | positioned), FIG. 5: each shows the figure which showed the other aspect (mode in which the core material 17 is arrange | positioned) of FIG.

  As will be described in detail later, in the present invention, when the resin molded product 1 having the hollow portion 16 therein is molded using two molten sheet-like resins 31 and 32, the thickness is uniform. The melted sheet-like resins 31 and 32 that are extruded so as to have the peripheral portions of the sheet-like resins 31 and 32 are welded together by clamping the molds 41 and 42 so that the hollow portions 16 are provided inside (or the inside The core material 17 is disposed on the resin molded product 1.

  A resin molded product 1 to be molded is a molded product having a U-shaped cross section (a U-shaped cross section). As shown in FIG. 1, as shown in FIG. , 12 are connected to each other. In FIG. 1, a wide connecting wall 13 is included. Moreover, in the structure shown in FIG. 1, the surface (wall) which connects the side edges 11 and 12 and the side edge of the connection wall 13 is not formed.

  2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line BB in FIG. As shown in FIGS. 2 and 3, the resin molded product 1 to be molded is composed of two sheet-like resins 31 and 32 (in FIGS. 1 to 5, the sheets 31 and 32), and the hollow portion. 16.

In consideration of the deep-drawn shape of the resin molded product 1 to be molded, for example, the angle formed by the perpendicular lines of the side walls 11 and 12 and the connecting wall 13 shown in FIG. 2 (as shown in FIG. 2). (Θ _A ) is 0 ° to 15 ° (preferably 3 ° to 10 °), and the thickness t of the side walls 11 and 12 is 30 mm or less. (Preferably 20 mm or less) and the depth d of the connecting wall 13 may be 30 mm or more (preferably 50 to 200 mm). The depth d of the connection wall 13 may be the shortest distance from the lowest surface of the side wall 11 (also the side wall 12) to the top surface of the connection wall 13, as shown in FIG.

FIG. 4 shows another embodiment of FIG. 2, and FIG. 5 shows another embodiment of FIG. 4 and 5
The mode which has arrange | positioned the core material 17 inside the resin molded product 1 (The core material 17 is arrange | positioned in the hollow part 16 shown in FIG.2 and FIG.3) is shown. By disposing the predetermined core material 17 on the resin molded product 1, various functions (thermal insulation, heat retention, mechanical degree, rigidity, etc.) can be imparted to the resin molded product 1. 4 and the like show an aspect in which the core material 17 is disposed in all the hollow portions 16 existing inside the side walls 11 and 12 and the connecting wall 13 in the resin molded product 1, but this is an example. The positions and portions where the core member 17 is arranged, such as the hollow portion 16 existing in both or one of the side walls 11 and 12, the hollow portion 16 existing inside the connecting wall 13, etc. are various functions required. It can be determined accordingly.

  Hereinafter, a first embodiment and a diagram of an embodiment of a molding method of the resin molded product 1 having the configuration shown in FIGS. 1 to 3 (the hollow portion 16 is formed and the core material 17 is not disposed in the hollow portion 16). An embodiment of a molding method of the resin molded product 1 having the configuration shown in FIGS. 1, 4, and 5 (the core material 17 is disposed in the hollow portion 16) will be described using a second embodiment.

(B) First embodiment:
A molding method according to the first embodiment of the present invention will be described with reference to the drawings. In this embodiment, in the shape of FIG. 1 described above, the AA cross section is represented by FIG. 2 and the BB cross section is represented by FIG. Hereinafter, “manufacturing mold” will be simply described as “mold”.

  FIG. 6 is a schematic view showing an aspect of the molding apparatus X. The molding apparatus X shown in FIG. 6 includes an extrusion apparatus P and a mold clamping apparatus Q disposed below the extrusion apparatus P. The molten sheet-like resin 31 extruded from the extrusion apparatus P1, and the extrusion Two sheet-like resins 31 and 32 (which becomes a parison; the same applies hereinafter) such as the molten sheet-like resin 32 extruded from the apparatus P2 are sent to the mold clamping apparatus Q, and the molten sheet is fed by the mold clamping apparatus Q. The shaped resins 31 and 32 are moved in a direction substantially orthogonal to the two divided molds 41 and 42, and the molds 41 and 42 are clamped and molded.

  That is, in the primary molding, the molten thermoplastic resin is extruded into a sheet having a predetermined width in a form that hangs downward from the extrusion slits 27a and 27b of the T dies 26a and 26b, and in the secondary molding, vacuum suction (evacuation) is performed. Is used to mold the resin molded product 1 through mold clamping of the molds 41 and 42 using the sheet-like resin extruded downward. At this time, the two sheet-like resins 31 and 32 are At the same time, for each of the sheet-like resins 31 and 32, the molten thermoplastic resin is extruded in a form that hangs downward from the extrusion slits 27a and 27b of the T dies 26a and 26b. The two sheet-shaped resins 31 and 32 that have been extruded are brought into contact with the movable molds 90 to 93 and vacuum suction is used to squeeze the sheet-shaped resins 31 and 32 into the mold 4. , And shaped into the shape of 42, through clamping, in which cross section forming the resin molded article 1 of the U-shaped.

(1) Extruder P:
The extrusion device P (extrusion devices P1 and P2) has a conventionally known configuration, and cylinders 22a and 22b provided with hoppers 21a and 21b, screws (not shown) provided in the cylinders 22a and 22b, and the like. The hydraulic motors 23a and 23b connected to the screw, the cylinders 22a and 22b, accumulators 24a and 24b communicated with each other, and plungers 25a and 25b provided inside the accumulators 24a and 24b.

  The pellets of the thermoplastic resin introduced from the hoppers 21a and 21b are melted and kneaded by rotation of the screws by the hydraulic motors 23a and 23b inside the cylinders 22a and 22b, and the thermoplastic resin (molten resin) in a molten state is accumulated in the accumulator 24a, It is transferred to 24b and stored in a certain amount. When the plungers 25a and 25b are driven, the molten resin is fed toward the T dies 26a and 26b, and the molten sheet-like resins 31 and 32 are continuously fed through the extrusion slits 27a and 27b. While being pinched by a pair of rollers (28a and 28c, 28b and 28d, hereinafter simply referred to as “28”) that are pushed and spaced apart, they are sent downward and divided. It hangs down between the molds 41, 42. Thereby, as will be described in detail later, the sheet-like resins 31 and 32 are arranged between the molds 41 and 42 in a state of having a uniform thickness in the vertical direction (extrusion direction).

  By feeding the sheet-like resins 31 and 32 sandwiched between the pair of rollers 28 by the rotation of the pair of rollers 28 downward, the sheet-like resins 31 and 32 can be stretched and thinned, and are extruded. By adjusting the relationship between the extrusion speed of the resins 31 and 32 and the delivery speed of the sheet-like resins 31 and 32 by the pair of rollers 28, it is possible to prevent the occurrence of drawdown or neck-in. , Especially melt flow rate (MFR) and melt tension, or restrictions on the amount of extrusion per unit time can be reduced.

  As shown in FIG. 6, the extrusion slits 27a and 27b provided in the T dies 26a and 26b are arranged vertically downward, and the sheet-like resins 31 and 32 extruded from the extrusion slits 27a and 27b are left as they are. In a form that hangs down from 27b, it is sent vertically downward. The sheet-like resins 31 and 32 extruded from the T dies 26a and 26b are adjusted so that the thickness in the extrusion direction becomes uniform in a state where they are suspended between the molds 41 and 42, that is, when the molds are clamped. Is preferred.

  The pair of rollers (28a and 28c, 28b and 28d) are arranged substantially horizontally in parallel with each other below the extrusion slits 27a and 27b. As shown in FIG. 6, a pair of roller 28 is arrange | positioned so that it may become line symmetrical about sheet-like resin 31 and 32 extruded in the form which hangs down from extrusion slit 27a, 27b. The thicknesses of the sheet-like resins 31 and 32 (the sheets 31 and 32 in the resin molded product 1) can be appropriately set according to, for example, the shape of the resin molded product 1 and the like.

(2) Mold clamping device Q:
The mold clamping device Q is in an open position in a direction substantially perpendicular to the supply direction of the two divided molds 41 and 42 and the molten sheet-like resins 31 and 32 (parisons). And a mold drive device (not shown) that moves between the closed position and the closed position.

  FIG. 7 is a view showing a state in which the sheet-like resins 31 and 32 are cut in a direction perpendicular to the hanging direction in FIG. Hereinafter, the basic configuration of the mold clamping device Q will be described with reference to FIGS. 6 and 7. Specific shapes of the molds 41 and 42 (male mold 41 and female mold 42) will be described later with reference to FIGS. On the other hand, the shapes of the molds 41 and 42 in FIGS. 6 and 7 are partially simplified for explanation. The pinch-off portions 83 and 84 do not actually appear on the cut surface, but are included for convenience of explanation.

  As shown in FIGS. 6 and 7, the two divided molds 41 and 42 are arranged with the core 43 and the cavity 44 facing each other. On the surfaces of the core 43 and the cavity 44, the shape of the resin molded product 1 molded based on the melted sheet-like resins 31 and 32 (parisons), and irregularities corresponding to the surface shape of the resin molded product 1 are provided. It will be. In carrying out the molding method of the present invention, as one of the two molds 41 and 42 (for example, the mold 41), the male mold 41 having one configuration shown in FIGS. As the metal mold 42), molding is carried out using a female mold 42 whose configuration is shown in FIGS.

  In the two divided types of male mold 41 and female mold 42, pinch-off portions 81 and 83 are formed around the core 43 of the male mold 41 so as to protrude toward the opposed female mold 42. Pinch-off portions 82 and 84 are formed around the cavity 44 of the mold 42 so as to protrude toward the opposing male mold 41. Due to the presence of the pinch-off portions 81, 82, 83, 84, when clamping the two divided types of the male die 41 and the female die 42, the respective pinch-off portions (the pinch-off portion 81 of the male die 41 and the pinch-off of the female die 42). And the tips of the pinch-off part 83 of the male mold 41 and the pinch-off part 84 of the female mold 42 are in contact with each other, and a parting line is formed at the periphery of the molten sheet-like resin 31, 32.

  In addition, a movable mold 90 (see FIG. 8 and the like for the movable mold 91) is provided around the male mold 41, and movable molds 92 and 93 (both in FIG. 11 and the like) are disposed around the mold (female mold 42). ) Is slidably attached, and the movable molds 90 and 91 are relative to the male mold 41 and the movable molds 92 and 93 are relatively relative to the female mold 42 with respect to a mold moving device (not shown). It can be moved.

  The movable molds 90 and 91 are disposed with respect to the male mold 41 and project toward the female mold 42, thereby side surfaces of the sheet-like resin 31 (parison) disposed between the male mold 41 and the female mold 42. The movable mold frames 92 and 93 are disposed with respect to the female mold 42 and project toward the male mold 41 to thereby form a sheet-like sheet disposed between the male mold 41 and the female mold 42. It is possible to contact the side surface of the resin 32 (parison).

  The movable mold 90 and the movable mold 91 located on the lower side of the movable mold 90 (see FIG. 8 to be described later) are movable with respect to the male mold 41. By adopting such a configuration, the movable mold 90 and the movable mold 91 can be separated and moved. First, after the movable mold 90 is moved and brought into contact with the sheet-like resin 31, The movable mold 91 can be moved and brought into contact with the sheet-like resin 31.

  In this embodiment, as shown in FIG. 11 described later, the two movable molds 92 and 93 with respect to the female mold 42 show a mode in which the molds 74 are vertically divided and attached. The movable molds 92 and 93 are movable with respect to the female mold 42. With such a configuration, the movable mold 92 and the movable mold 93 can be moved separately. Further, for example, the movable mold 92 and the movable mold 93 are moved to the height of the mold 74 sandwiched between the movable molds 92 and 93, and all of them are brought into contact with the sheet-like resin 32. Good.

  The mold 74 is basically a fixed (non-movable) mold, and the top surface is fixed at a position higher than the height of the top surface of the inner fixed mold 73 as will be described later. Alternatively, the inner fixed mold 73 may be moved so as to be retractable to the height. In the following description, it is assumed that the mold 74 is a mold 74 that can be moved in this manner.

  The mold driving device (not shown) is the same as the conventional one, and the description thereof will be simplified. However, the two divided male and female dies 41 and 42 are respectively driven by the mold driving device. In the open position, the melted sheet-like resins 31 and 32 can be disposed between the male mold 41 and the female mold 42, while the pinch-off portions 81 and 83 of the male mold 41 and the female mold are disposed in the closed position. The pinch-off portions 82 and 84 of 42 are in contact with each other, so that a sealed space S 1 is formed inside the male mold 41 and a sealed space S 2 is formed inside the female mold 42. As for the movement of the male mold 41 and the female mold 42 from the open position to the closed position, the closed position is the position of the center line of the molten sheet-like resin 31, 32, and the male mold 41 and the female mold 42 are molds. It is driven by the driving device so as to move toward the position.

  In addition, a vacuum suction chamber (not shown) is provided inside the male mold 41 and the female mold 42, and the vacuum suction chamber is connected to the core 43 of the male mold 41 and the female mold 42 via a suction portion (also not shown). By communicating with the cavity 44 and performing vacuum suction from the vacuum suction chamber through the suction portion, the sheet-like resins 31 and 32 are adsorbed toward the core 43 and the cavity 44, and along the outer surfaces of the core 43 and the cavity 44. The shape is shaped into a different shape. Furthermore, the periphery of the core 43 and the cavity 44, the movable molds 90 to 93, the inner fixed mold 73, and the mold 74 are also provided with a suction unit (not shown) capable of vacuum suction. Details of these suction portions will be described later.

(2-1) Configuration of male mold 41:
Hereinafter, an aspect of the configuration of the male mold 41 among the molds (the male mold 41 and the female mold 42) for performing the molding method according to the present invention will be described with reference to FIGS. FIG. 8 is a schematic diagram showing an aspect of the configuration of the male mold 41 (viewed from the surface facing the sheet-like resin 31), FIG. 9 is a cross-sectional view taken along the line CC in FIG. 8, and FIG. FIG. 8 is a sectional view taken along line D-D. Note that FIG. 9 (and FIG. 15 to be described later) does not show hatching (hatch).

  As shown in FIG. 7, the core 43 of the male mold 41 has a substantially turret shape that is convex toward the molten sheet-like resin 31 and is shown in FIGS. 1 to 3 to be molded. The cross section has a shape corresponding to the shape of the U-shaped resin molded product. The core 43 includes a connecting wall forming portion 53a that forms the connecting wall 13 of the resin molded product 1, side wall forming portions 51a and 52a that form a pair of side walls 11 and 12, and non-wall forming portions 54a and 55a that do not form a wall. It is formed including.

  FIG. 9 is a cross-sectional view taken along the line CC of FIG. 8 and shows a cross-sectional structure around one side wall forming portion 51a. As shown in FIG. 9, the cross-sectional structure around the side wall forming portion 51 a (same as the side wall forming portion 52 a) in the male die 41 is outward from the pinch-off portion 81 connected to the core 43 (outward of the male die 41, For example, in FIG. 9, the plane portion 61, the male inclined surface portion 62 that inclines upward, and the bank portion 63 are continuously formed in the direction toward the moving mold 90. The plane portion 61, the male inclined surface portion 62, and the preferably formed bank portion 63 are continuously formed in the longitudinal direction of the pinch-off portion 81 outward from the pinch-off portion 81. In addition, as long as the effect can be obtained, a portion that is not formed may be included.

  The flat surface portion 61 is a flat surface that is disposed along the longitudinal direction of the side wall forming portion 51 a and is continuously formed between the pinch-off portion 81 and the end portion of the male inclined surface portion 62. The width W1 of the flat surface portion 61 (for example, from the end portion of the pinch-off portion 81 serving as the starting end of the flat surface portion 71 or the outside thereof (the portion indicated by the dotted line Z in FIG. 9) to the end portion of the male inclined surface portion 62 described later) In general, it is preferably 15 mm or more, particularly preferably 30 to 150 mm.

  The male inclined surface portion 62 is disposed along the longitudinal direction of the side wall forming portion 51 a, and the inclined surface that is inclined outwardly from the flat surface portion 61 has an end portion of the flat surface portion 61 and an end portion of the bank portion 63. It becomes the surface formed continuously between. The width W2 of the male inclined surface portion 62 (for example, from the end portion of the flat surface portion 71 to the end portion of the bank portion 63) is preferably approximately 50 to 150 mm.

  The bank portion 63 is a flat surface that is disposed over the longitudinal direction of the side wall forming portion 51 a and is formed outward from the end portion of the male inclined surface portion 62. The outer end of the bank portion 63 is the outer end of the mold (male mold 41), and a movable mold frame 90 is attached to the outer side of the bank portion 63. The width W3 of the bank 63 (for example, from the end of the male inclined surface 62 to the outer end of the mold (male 41)) is preferably about 5 to 50 mm.

  In the male mold 41, the flat surface portion 61 and the male inclined surface portion 62 are formed outside the pinch-off portion 81 in the side wall forming portions 51a and 52a so as to be continuous with the pinch-off portion 81. There are the following merits. That is, when the sheet-like resin 31 drawn to the male die 41 side by the movable molds 90 and 91 comes into contact with the core 43 of the male die 41, the sheet-like resin 31 is moved outward of the pinch-off portion 81 (the movable die frame 90). Since the sheet-like resin 31 can be appropriately drawn toward the side wall forming portions 51a and 52a of the core 43 while being pulled toward the side), the side walls 11 and 12 are formed with an equal thickness, and the thin portions at the side walls 11 and 12 are formed. And pinholes can be suppressed.

  On the other hand, when the flat surface portion 61 and the male inclined surface portion 62 (and the bank portion 63) are not formed, the outer side of the pinch-off portion 81 is substantially flat including the movable mold frame 90. When the vacuum suction is performed, the sheet-like resin 31 is extended to the side wall forming portions 51a and 52a side of the core 43 and is also extended to the movable mold 90 side, so that the periphery of the pinch-off portion 81 is entirely thin. As a result, a thin portion, a pinhole or the like is generated. In addition, since it takes time for vacuum suction, the sheet-like resins 31 and 32 are cooled during that time, so that the moldability is deteriorated, which adversely affects the resin molded product 1 itself. In addition, the energy required for vacuum suction is excessive, which may lead to high costs such as electricity costs.

  When only the male inclined surface portion 62 is formed without forming the flat surface portion 61, the male inclined surface portion 62 is directly connected to the outside of the pinch-off portion 81, so that vacuum suction is performed by the core 43 of the male die 41. In this case, the periphery of the pinch-off part 81 is narrow in the width direction, and a pointed downward space is formed. As a result, with vacuum suction, the vicinity of the pinch-off portion 81 becomes thin, and a thin portion or the like is generated. Therefore, the flat portion 61 and the male inclined surface portion 62 are formed outside the pinch-off portion 81 so as to be continuous with the pinch-off portion 81.

The inclination angle of the male inclined surface portion 62 (the angle θ _B formed by the straight line extending from the end of the flat surface portion 61 and the inclined surface of the male inclined surface portion 62) is preferably approximately 20 ° to 80 °. It is particularly preferable to set the angle to 60 °. If the inclination angle θ _B is smaller than 20 °, the inclination is so gentle that the outside of the pinch-off portion 81 becomes substantially flat including the movable mold 90, and the same problem as described above may occur. On the other hand, if the inclination angle θ _B is greater than 80 °, the inclination is too steep and the sheet-like resin 31 is less likely to come into contact with the male inclined surface portion 62, and the effect of providing the male inclined surface portion 62 and the like is not exhibited. When the sheet-shaped resin 31 comes into contact with the male mold 41, the temperature of the sheet-shaped resin 31 is higher than the temperature of the male mold 41, so that the sheet-shaped resin 31 is cooled and the elongation of the sheet-shaped resin 31 is deteriorated. If it is within the range, the periphery of the pinch-off portion 81 is appropriately narrowed, and the male inclined surface portion 62 and the sheet-like resin 31 are easily brought into contact with each other. It becomes easy to be extended.

  In addition, formation of the bank part 63 is preferable because the sheet-shaped resin 31 can be securely held in close contact with the movable mold 90 and the bank part 63 in contact with each other. By forming the bank portion 63, the behavior in which the sheet-like resin 31 is excessively extended toward the side wall forming portions 51a and 52a of the core 43 can be suppressed, and the above-described effects can be efficiently achieved. On the other hand, when the bank portion 63 is not formed, the sheet-like resin 31 is first brought into contact with the male inclined surface portion 62 of the male mold 41 and is vacuum-sucked by the male mold 41. Since the end portion of the sheet-like resin 31 is held, the sheet-like resin 31 is extended to the side wall forming portions 51a and 52a of the core 43. End up. As a result, the sheet-shaped resin 31 may be peeled off from the movable mold 90 and the male mold 41, and the sealed state may not be maintained.

  FIG. 10 is a sectional view taken along the line DD of FIG. As shown in FIG. 10, a pinch-off portion 83 is formed at the height of the connecting wall forming portion 53a as a cross-sectional structure around the wall non-forming portion 54a (the same applies to the wall non-forming portion 55a). On the other hand, as shown in FIG. 9, which is a cross-sectional structure around the side wall forming portion 51a, the male mold 41 is lowered from the connecting wall forming portion 53a, and the side wall forming portion 51a and the pinch-off portion 81 are continuously formed. In the side wall forming part 51a, the pinch-off part 81 is formed at a position lower than the height of the connecting wall forming part 53a. As described above, when the resin molded product 1 having a U-shaped cross section in which the side surfaces (walls) connecting the side walls 11 and 12 and the side walls of the connecting wall 13 are not formed is formed, the pinch-off portion 81 of the male mold 41, 83 is formed at a position where the pinch-off part 81 of the side wall forming part 51a and the pinch-off part 83 of the wall non-forming part 54a have different heights. The same applies to the pinch-off portions 82 and 84 (the pinch-off portion 82 of the side wall forming portion 51b and the pinch-off portion 82 of the wall non-forming portion 54b) described later.

  As shown in FIG. 10, the cross-sectional structure around the wall non-forming portion 54 a in the male mold 41 is such that a pinch-off portion 83 is formed in the connecting wall forming portion 53 a and outward from the pinch-off portion 83 (outward of the male die 41. For example, the height of the core 43 is continuously maintained in the direction of the movable mold 90 in FIG. 10, and the bank is formed outward of the wall non-forming portion 54 a when further outward. The flat portion 64 has substantially the same height as the portion 63. The outer end of the flat part 64 is the outer end of the male mold 41, and the movable mold frame 90 is attached to the outer side of the flat part 64.

  Further, a vacuum suction chamber (not shown) is provided inside the male mold 41, and the vacuum suction chamber communicates with the core 43 via a suction portion (not shown) (described later), and the suction portion is connected to the vacuum suction chamber. The sheet-shaped resin 31 is adsorbed toward the core 43 by vacuum suction, and is shaped into a shape along the outer surface of the core 43.

  At the time of vacuuming in the male mold 41, the side wall forming portions 51a and 52a, the pinch-off portions 81 and 83, the flat surface portion 61, the male inclined surface portion 62 and the bank portion 63 (hereinafter referred to as “from the side wall forming portions 51a and 52a to the bank portion 63). The suction part (not shown) is preferably formed around the pinch-off part 81 of the side wall forming part 51a and the flat part 61, for example. As will be described later, the sheet-like resin 31 comes into contact with the male mold 41 and is shaped while being sucked and held by the movable molds 90 and 91.

  By forming a suction portion around the pinch-off portion 81 and the flat portion 61 and evacuating the core, the sheet-like resin 31 from the flat portion 61 to the bank portion 63 is sucked and held by the movable mold 90. Thus, the sheet-like resin 31 can be appropriately drawn toward the side wall forming portions 51a and 52a of 43, which helps to equalize the thickness of the side walls 11 and 12 of the resin molded product 1. The evacuation by the suction part may be performed around the pinch-off part 81 of the side wall forming part 51 a or one of the flat part 61, and is preferably formed both around the pinch-off part 81 and the flat part 61.

  Thus, the suction part is formed on the periphery of the pinch-off part 81 of the side wall forming parts 51a and 52a and the flat part 61, and the sheet-like resin 31 from the flat part 61 to the bank part 63 is formed on the side wall forming part 51a, In view of the appropriate pulling toward the 52a side, the suction part from the side wall forming parts 51a, 52a of the male mold 41 to the bank part 63 is formed on the periphery of the pinch-off part 81 of the side wall forming parts 51a, 52a and the flat part 61. In comparison, the male inclined surface portion 62 is not so necessary, and the bank portion 63 may or may not be formed.

  Note that the movable molds 90 and 91 (similar to the movable molds 92 and 93 to be described later) arranged around the male mold 41 also hold the sheet-shaped resin 31 at the time of molding. A suction part (not shown) is provided on the contacting surface, and vacuuming can be performed. It is preferable that the suction part is formed evenly over the entire surface of the movable molds 90 and 91. By performing vacuum suction through such a suction portion, the sheet-like resin 31 can be reliably adhered toward the surfaces of the movable molds 90 and 91. The shape of the suction portion may be a conventionally known shape such as a circular, elliptical, or polygonal hole (hole), or a slit shape (also referred to as a linear shape or a groove shape). it can.

  The suction part formed in the movable molds 90 and 91 (the movable molds 92 and 93, the inner fixed mold 73 and the mold 74 are described later) forms the resin molded product 1 having a U-shaped cross section. In view of this, a slit shape is preferable. In molding the resin molded product 1 having a U-shaped cross section, since the force with which the sheet-like resins 31 and 32 are attracted to the core 43 and the cavity 44 is increased, the sheet is also formed on the movable molds 90 and 91 side. If the shaped resins 31 and 32 are not reliably sucked and adhered, the thickness of the side walls 11 and 12 may not be uniform.

  From the above, it is preferable that the suction portions of the movable molds 90 and 91 have a slit shape rather than a general (vent) hole. The sheet-like resin 31 can be securely held outside the pinch-off portion 81.

(2-2) Configuration of female mold 42:
Next, with reference to FIG. 11 to FIG. 15, one aspect of the configuration of the female mold 42 among the molds 41 and 42 for performing the molding method according to the present invention will be described. FIG. 11 is a schematic diagram showing an embodiment of the configuration of the female mold 42 (a diagram viewed from the surface facing the sheet-like resin 32), FIG. 12 is a cross-sectional view taken along line EE in FIG. 11, and FIG. FIG. 14 is a schematic view showing the female inclined surface portion 72 and its periphery, and FIG. 15 is a view showing a sectional structure of the female inclined surface portion 72 and its periphery.

  The cavity 44 of the female mold 42 has a concave shape toward the melted sheet-like resin 32, and, like the male mold 41, the resin molded product 1 shown in FIGS. The shape corresponds to the shape. The cavity 44 also includes a connecting wall forming portion 53b that forms the connecting wall 13 of the resin molded product 1, side wall forming portions 51b and 52b that form the pair of side walls 11 and 12, and non-wall forming portions 54b and 55b that do not form walls. It is formed including.

  Further, as shown in FIG. 11 and the like, the movable mold frames 92 and 93 that are movable with respect to the female mold 42 surround the mold frame 74 at a position toward the non-wall-forming portion 54b when viewed from the mold frame 74. It is attached.

  FIG. 12 is a cross-sectional view taken along the line EE of FIG. 11 and shows a cross-sectional structure around the side wall forming portion 51b. As shown in FIG. 12, the cross-sectional structure around the side wall forming portion 51 b (same as the side wall forming portion 52 b) in the female die 42 is outward from the pinch-off portion 82 connected to the cavity 44 (outward of the female die 42, For example, in FIG. 12, the inner fixed mold 73 is formed continuously as a surface formed toward the inner fixed mold 73 and the mold 74. A mold 74 is formed outside the inner fixed mold 73. The inner fixed mold 73 is formed integrally with the female mold 42, and the mold 74 is fixed at a position slightly higher than the height of the inner fixed mold 73 in this embodiment. On the other hand, it is possible to retreat (move) to the height of the inner fixed mold 73.

  As shown in FIG. 12, the top surface of the mold 74 is preferably slightly higher than the top surface of the inner fixed mold 73 (hereinafter, the height is referred to as the height of the top surface). As shown in FIG. 12, the inner fixed mold 73 is lower than the pinch-off portion 82, and when the mold 74 is at the same height as the inner fixed mold 73, the sheet pulled by the movable molds 92 and 93. First, the resin-like resin 32 comes into contact with the pinch-off portion 82, and the soft sheet-like resin 32 in the molten state may not be able to adhere well to the female mold 42.

  On the other hand, when the sheet-shaped resin 32 is brought into close contact with the movable molds 92 and 93 by fixing the mold 74 with a high height, the movable molds 92 and 93 are placed at the height of the mold 74. By combining them, the sheet-like resin 32 first comes into contact with the mold 74 and the movable molds 92 and 93, and the sheet-like resin can be reliably held by the mold 74 and the movable molds 92 and 93. it can. The height of the mold 74 is higher than the height of the pinch-off portion 82, preferably 2 to 30 mm higher than the inner fixed mold 73, and particularly preferably 5 to 20 mm higher.

  The pinch-off part 82 is continuously formed on the top of the concave cavity 44 over the longitudinal direction of the side wall forming part 51b, and is higher than the pinch-off part 84 formed on the wall non-forming part 54b described later. Has been.

  13 is a cross-sectional view taken along the line FF in FIG. 11 and shows a cross-sectional structure around the wall non-forming portion 54b. As shown in FIG. 12, the cross-sectional structure around the wall non-forming part 54 b (same as the wall non-forming part 55 b) in the female mold 42 is formed with a pinch-off part 84 formed on the surface connected to the cavity 44, An appropriate slope that increases toward the movable mold frame 92 side is formed toward the direction (outward of the female mold 42, for example, in the direction of the movable mold frame 92 in FIG. 13). Is formed. In addition, a movable mold frame 92 that is movable with respect to the female mold 42 exists outside the flat portion 71. Thus, the pinch-off portion 84 is formed continuously at the bottom of the concave cavity 44 over the longitudinal direction of the wall non-forming portion 54b, and is compared with the pinch-off portion 82 formed on the side wall forming portion 51b. The position is low.

  As described above, the pinch-off portions 81 and 83 formed on the male die 41 and the pinch-off portions 82 and 84 formed on the female die 42 are separated from the side wall forming portions (51a and 52a in the male die 41, female 51b, 52b in 42), the pinch-off part 81 formed at a low position of the male mold 41 and the pinch-off part 82 formed at a high position of the female mold 42 come into contact with each other, and a non-wall-forming part ( 54a and 55a in the male mold 41 and 54b and 55b in the female mold 42), a pinch-off portion 83 formed at a high position of the male mold 41 and a pinch-off section 84 formed at a low position of the female mold 42 are provided. By abutting, a parting line is formed.

  FIG. 14 is a schematic view showing the female inclined surface portion 72 and its periphery. As shown in FIGS. 11 and 14, the outer side of the pinch-off part 82 in the side wall forming part 51b (not shown, but also the side wall forming part 52b) of the female mold 42 (as described above, the outer side of the female mold 42, For example, in FIG. 12, the inner fixed mold 73, which is a surface formed along the longitudinal direction of the inner fixed mold 73 and the mold 74), is provided on both ends of the inner fixed mold 73 on the wall non-forming portions 54 b and 55 b side. A female inclined surface portion 72 having an inclined surface that is lowered toward the outside of the longitudinal direction of 73 (in the direction of the arrow placed near the female inclined surface portion 72 in FIG. 11) is formed. As shown in FIG. 14, the female inclined surface portions 72 formed of inclined surfaces formed at both ends of the inner fixed mold frame 73 are connected to the flat portions 71 constituting the wall non-forming portion 54 b.

  The sheet-like resin 32 held in close contact with the movable molds 92 and 93 is moved to the pinch-off portions 82 and 84 when the movable mold frames 92 and 93 are retracted toward the female mold 42 and come into contact with the cavity 44. 82 (the higher one) and then the pinch-off portion 84 (the lower one). Here, the movable molds 92 and 93 need to be retracted to the vicinity of the lowest position (for example, the flat portion 71) of the female mold 42 in order to reliably perform the shaping in the cavity 44. If the female mold 42 is brought into close contact with the movable mold frames 92 and 93 without retreating, the lowest part (the connecting wall forming portion) is formed in the cavity 44 of the female mold 42 having a U-shaped cross section. 53b, the pinch-off portion 84, etc.) The sheet-like resin 32 in the vicinity is extended and becomes thin, which may cause problems such as pinholes and insufficient strength.

  As described above, the pinch-off part 82 is formed on the top of the concave cavity 44, and the pinch-off part 84 is formed on the surface connected from the bottom surface of the cavity 44, and the heights of the pinch-off parts 82 and 84 are different (the pinch-off part 82). Therefore, when the movable molds 92 and 93 are moved backward, the difference in height causes the vicinity of both ends of the inner fixed mold 73, such as the vicinity of the portion where the pinch-off portions 82 and 84 intersect. There is a problem that the sheet-like resin 32 is peeled off from the inner fixed mold 73 which is a surface formed outward from the pinch-off portion 82. In that case, the sealed space (for example, the sealed space S2 in FIG. 16) between the sheet-like resin 32 and the female mold 42 cannot be maintained, and can be shaped into a shape that follows the shape of the cavity 44. Disappear.

  On the other hand, by forming the female inclined surface portions 72 at both ends of the inner fixed mold 73 on the wall non-forming portions 54b and 55b side, the female inclined surface portion 72 has pinch-off portions 82 and 84 having different heights. Therefore, the occurrence of the above-mentioned problem is prevented. That is, in the portion where the female inclined surface portion 72 is formed, the sheet-like resin 32 comes into contact with the pinch-off portions 82 and 84 with the female inclined surface portion 72 interposed therebetween. The pinch-off part 84 and the pinch-off part 82 can be connected, and as a result, it is possible to prevent the sheet-like resin 32 from being peeled off (the sealed space S2 is released) at the switching position with the inner fixed mold 73. it can.

FIG. 15 is a diagram showing a cross-sectional structure of the female inclined surface portion 72 and its periphery. As shown in FIG. 15, the female inclined surface portion 72 is inclined so as to be lowered from the top surface of the inner fixed mold 73 (the surface facing the sheet-like resin 32) to the surface connected to the flat portion 71 of the wall non-forming portion 54b. The inclination angle θ _C of the female inclined surface portion 72 is preferably 20 ° to 70 °, and particularly preferably 30 ° to 50 °, in order to efficiently achieve the above-described effects. Moreover, as shown in FIG. 15, it is preferable that the female inclined surface portion 72 is formed so that its length L1 is approximately 30 to 120 mm in order to efficiently exhibit the above-described effects. The female inclined surface portion 72 may be formed wider than the inner fixed mold 73 as shown in FIGS. 11 and 14, but the width of the female inclined surface portion 72 is the shape of the female die 42. It can be arbitrarily determined according to the size and the like.

  The sheet-like resin 32 is fixed on the inner side while the movable molds 92 and 93 are retracted after the sheet resin 32 is securely held in close contact with the mold 74 that has been vacuum-sucked and the movable molds 92 and 93. It closely adheres to the mold 73 and the female inclined surface portion 72 (both vacuum suction). When vacuum suction is performed by the inner fixed mold 73, it immediately comes into contact with the pinch-off portion 82 that is the inner portion thereof. The timing of vacuum suction of the inner fixed mold 73 and the female inclined surface portion 72 and the timing of retraction of the movable molds 92 and 93 are substantially the same, but are not substantially the same, either one comes first. There is no problem.

  A suction part (not shown) is formed in the inner fixed mold 73, the mold 74, the movable mold 92, and the cavity 44. By suctioning through the suction part, the inner fixed mold 73, the mold 74, and the movement are moved. The sheet-like resin 32 can be adsorbed toward the surface of the mold 92 (also the movable mold 93). By sucking the sheet-like resin 32 in a vacuum toward the surface of the mold 74 or the movable mold 92, the sheet-like resin 32 can be reliably sucked and held.

  Similarly to the male die 41, a vacuum suction chamber (not shown) is provided inside the female die 42. The vacuum suction chamber communicates with the cavity 44 via a suction portion (not shown), and the vacuum suction chamber passes through the suction portion. By vacuum suction, the sheet-like resin 32 is adsorbed toward the cavity 44 and shaped into a shape along the outer surface of the cavity.

  At the time of evacuation in the female mold 42, it is preferable that the suction part for evacuation is formed in the vicinity of the pinch-off part 82 toward the outside of the pinch-off part 82 in the side wall forming parts 51b and 52b. By forming a suction part in the vicinity of the pinch-off part 82 so that vacuuming can be performed, the sheet-like resin 32 can be stably maintained in close contact with the periphery of the pinch-off part 82, and the side walls 11 and 12 can be drawn. The thickness can be made even. The suction part is preferably formed, for example, at a position within approximately 10 mm when viewed from the pinch-off part 82 so that vacuuming can be performed. Further, as described above, it is preferable to form a suction portion for evacuation as shown in FIG. 14 in the adjacent inner fixed mold 73 and mold 74 as well.

(3) Sheet resin 31, 32 (Parison)
The resin material constituting the sheet-like resins 31 and 32 (parison) is not particularly limited as long as it is a thermoplastic resin, and for example, a polyolefin-based resin, a so-called engineering plastic, or the like can be used. In addition, as a resin material which comprises the sheet-like resins 31 and 32, it is preferable to use a resin material having a high melt tension from the viewpoint of preventing a variation in thickness due to drawdown, neck-in, or the like. Therefore, it is preferable to use a resin material having high fluidity in order to improve transferability to the mold and followability.

  Specifically, polyolefin resins which are homopolymers or copolymers of olefins such as ethylene, propylene, butene, isoprene pentene and methyl pentene can be used. For example, polypropylene, high density polyethylene (HDPE) Etc. can be used.

  Furthermore, the resin material constituting the sheet-like resins 31 and 32 may contain an additive. Examples of the additive include inorganic materials such as silica, mica, talc, calcium carbonate, glass fiber, and carbon fiber. Examples include fillers, plasticizers, stabilizers, colorants, antistatic agents, flame retardants, and foaming agents.

(4) Example of molding method:
An example of the molding method of the resin molded product 1 having the above-described configuration will be described below with reference to the drawings.

(I) Extrusion and arrangement of the sheet-like resins 31 and 32 (first step):
First, a predetermined amount of the melted and kneaded thermoplastic resin is stored in the accumulators 24a and 24b shown in FIG. 6, and the stored thermoplastics from the extrusion slits 27a and 27b provided in the T dies 26a and 26b. The resin is intermittently extruded at a predetermined extrusion rate per unit time. Thus, the molten sheet-like resins 31 and 32 are extruded at a predetermined extrusion speed with a predetermined thickness so as to hang downward.

  Next, by driving a piston-cylinder mechanism (not shown), a pair of rollers (28a and 28c, 28b and 28d, hereinafter simply referred to as “roller 28”) is moved to the open position, and the extrusion slits 27a and 27b. By extending the distance between the pair of rollers 28 arranged below the thickness of the sheet-like resins 31 and 32, the lowermost portion of the molten sheet-like resins 31 and 32 extruded downward is the pair of rollers 28. Make sure that it is supplied smoothly.

  Next, the sheet-like resins 31 and 32 having a uniform thickness in the extrusion direction are arranged between the two male molds 41 and the female molds 42 existing below the pair of rollers 28 (see FIGS. 6 and 6 described above). 7).

(Ii) Movement of the movable molds 90 to 93 and shaping of the sheet-like resins 31 and 32 (second step):
The extruded sheet-like resins 31 and 32 are suspended between the male mold 41 and the female mold 42. In the male mold 41, the sheet-like resin 31 is passed through the lower position of the movable mold 91 in a state where the movable mold 90 is advanced and protruded from the height of the top surface of the male side 41.

  Further, the movable mold 91 is moved forward toward the sheet-shaped resin 31 to be the same position as the movable mold 90, and then the entire male mold 41 is moved forward so that the movable molds 90 and 91 are moved to the sheet-shaped resin 31. Make contact. Thereby, the sheet-like resin 31 can be brought into contact with the entire contact surface of the movable mold frames 90 and 91.

  After the sheet-shaped resin 31 is brought into contact with the entire contact surfaces of the movable molds 90 and 91, air is sucked from a suction portion (not shown) provided on the contact surfaces, and the sheet-shaped resin 31 is moved to the movable mold frames. Vacuum suction to the 90, 91 side. Thereby, the sheet-like resin 31 can be adhered to the contact surface.

  In the female mold 42, the movable mold frame 92 is advanced to the position of the mold frame 74, and the movable mold frame 93 is moved to the mold frame in a state where the sheet-like resin 32 passes through the movable mold frame 93 which is the lower movable mold frame. After being advanced to the position 74, the entire female mold 42 is advanced until the movable mold frames 92 and 93 and the mold frame 74 abut against the sheet-like resin 32. Thereby, the sheet-like resin 32 can be brought into contact with the entire contact surfaces of the movable mold frames 92 and 93 and the mold frame 74.

  After the sheet-like resin 32 is brought into contact with the entire contact surfaces of the movable mold frames 92 and 93 and the mold frame 74, air is sucked from a suction portion (not shown) provided on the contact surfaces, and the sheet-like resin 32 is drawn. Is vacuum-sucked to the movable molds 92 and 93 and the mold 74 side. Thereby, the sheet-like resin 32 can be tightly held on the contact surface.

  FIG. 16 is a diagram showing a state in which the movable molds 90 to 93 are brought into contact with the sheet-like resins 31 and 32 (the movable molds 90 and 91 are placed on the sheet-like resin 31 and the movable molds 92 and 93 (and FIG. 6 is a view showing a state in which a mold 74 (not shown) is brought into contact with the sheet-like resin 32). By the above-described operation, the movable mold frames 90 and 91 corresponding to the sheet-shaped resin 31 and the male mold 41 move the sealed space S1, the movable mold frames 92 and 93 (and the unillustrated mold frame 74) corresponding to the sheet-shaped resin 32, and the female. Sealed spaces S2 are formed by the molds 42, respectively.

  In the male mold 41, the movable mold frames 90 and 91 are brought into contact with the side surfaces of the sheet-like resin 31, and then the movable mold frames 90 and 91 are moved (retracted) to the male mold 41 side while being evacuated. The sheet-like resin 31 is moved to the male mold 41 side (core 43 side) so that the sheet-like resin 31 is formed on the movable mold frames 90, 91 → the non-wall-forming portions 54a, 55a. ) → bank portion 63 → male inclined surface portion 62 → pinch-off portion 81 (lower one) disposed on the side wall forming portions 51a and 52a.

  In the female mold 42, the movable mold frames 92 and 93 and the mold frame 74 are brought into contact with the side surfaces of the sheet-like resin 32, and then the movable mold frames 92 and 93 are evacuated and the female mold 42. Is moved (retracted) to the side, the mold 74 is stopped at the position of the inner fixed mold 73, the movable molds 92 and 93 are moved (retracted), and the sheet-like resin 32 is moved to the mold 42 side (cavity 44 side). The sheet-like resin 32 is moved to the movable mold frames 92 and 93 and the mold frame 74 → the pinch-off portion 82 (the higher one) disposed on the side wall forming portions 51b and 52b → the inner fixed mold frame 73 → female. The mold abutment surface portion 72 is in contact with the pinch-off portion 84 (having the lower height) formed in the wall non-forming portions 54b and 55b in this order.

  At the same time, the air in the sealed spaces S1 and S2 is sucked from a vacuum suction chamber (not shown) via a suction part (also not shown), and is evacuated, whereby the sheet-like resin 31 becomes the core 43 of the male die 41. The sheet-like resin 32 is adsorbed to the cavity 44 of the female mold 42. Thereby, the sheet-shaped resin 31 is shaped along the shape of the core 42 of the male mold 42, and the sheet-shaped resin 32 is shaped along the shape of the cavity 44 of the female mold 42.

  In this case, even in the movable molds 90 to 93 and the mold 74, the movable molds 90 and 91 are moved to the male mold 41 side in a state of being sucked and evacuated from a suction unit (not shown). By moving the molds 92 and 93 (and the mold 74) to the female mold 42 side, the sheet-like resins 31 and 32 can be drawn to the mold side (core 43 and cavity 44 side), and shaping is efficient. Well implemented.

  FIG. 17 is a schematic view showing a state in which the sheet-like resins 31 and 32 are shaped on the mold (male mold 41 and female mold 42). FIG. 17 shows a surface cut in a direction orthogonal to the side wall forming portions 51a, 51b, 52a, and 52b (the same applies to FIGS. 18, 20 and 21 described later).

  As shown in FIG. 17, since the flat part 61 and the male inclined surface part 62 (and bank part 63) are formed outside the pinch-off part 81 on the male die 41 side, the thickness of the side walls 11 and 12 is increased. Can be even.

  Further, on the female mold 42 side, due to the presence of the female inclined surface portion 72 formed on the mold 74, the sheet-like resin 32 is transferred at the switching position with the inner fixed mold 73 when the movable molds 92 and 93 are retracted. The pinch-off part 84 and the pinch-off part 82 can be reliably connected to each other through the female inclined surface part 72, and the shape following the shape of the cavity 44 is prevented. Can be shaped.

(Iii) Clamping (third process):
FIG. 18 is a schematic view showing a state where the mold is clamped. The moving molds 90 and 91 and the male mold 41 are moved together, and the moving mold frames 92 and 93 and the female mold 42 are moved together so as to be close to each other, whereby the male mold 41 and the female mold 42 are clamped. Is done. When the pinch-off portions 81 and 83 of the male mold 41 and the pinch-off portions 82 and 84 of the female mold 42 come into contact with each other, the peripheral portions of the two sheet-like resins 31 and 32 are welded to each other. A hollow portion 16 is formed inside 32.

  Further, at the time of clamping, as described above, the pinch-off portion 81 formed at a low position of the male die 41 in the side wall forming portions (51a, 52a in the male die 41, 51b, 52b in the female die 42). And the pinch-off portion 82 formed at a high position of the female mold 42 abuts. Further, although not shown in FIG. 18, in the non-wall-forming portions (54 a and 55 a in the male mold 41 and 54 b and 55 b in the female mold 42), The pinch-off part 84 formed at a low position of the female die 42 comes into contact.

  Thereafter, the movable molds 90 and 91 and the male mold 41, and the movable molds 92 and 93 and the female mold 42 are moved integrally away from each other, so that the male mold 41 and the female mold 42 are opened. Made. Then, the molded resin molded product 1 is taken out, burrs formed around the parting line are removed, and the secondary molding is completed.

(5) Effects of the present invention:
According to the present invention described above, the melted sheet-like resins 31 and 32 are shaped into the shapes of the core 43 of the male mold 41 and the cavity 44 of the female mold 42 by using vacuum suction in secondary molding, Thereafter, the male mold 41 and the female mold 42 are clamped, the sheet-shaped resins 31 and 32 are bonded together so that the peripheral portions of the sheet-shaped resins 31 and 32 are welded together, and the cross-section is a U-shaped resin. When molding the molded product 1, the outer side of the pinch-off part 81 in the side wall forming parts 51 a and 52 a of the male mold 41 has a specific shape. With such a shape, the sheet-like resin 31 can be appropriately drawn toward the side wall forming portions 51a and 52a of the core 43 while the sheet-like resin 31 is drawn toward the outside of the pinch-off portion 81. Can be provided, and the manufacturing method of the resin molded product 1 and the mold 41 of the resin molded product 1 can be provided.

(C) Second embodiment:
A second embodiment of the present invention will be described with reference to the drawings. In the following description, the same structure and the same members as those described above are denoted by the same reference numerals, detailed description thereof will be omitted or simplified, and characteristic portions of the present embodiment will be described in detail.

  The core material 17 has a cross section that can be placed inside the resin molded product 1 by molding a conventionally known resin material or the like for the purpose of improving heat insulation, heat retention, mechanical strength or elasticity, for example. As a letter shape, it can be arranged inside the resin molded product 1. Regarding the resin molded product 1, in the first embodiment described above, the resin molded product in which the core material 17 is not disposed in the hollow portion 16 shown in FIGS. 1 to 3 using the two sheet-like resins 31 and 32. 1 and described. On the other hand, in this embodiment, in the shape of FIG. 1 described above, the AA sectional view is represented by FIG. 4 and the BB sectional view is represented by FIG. The resin molded product 1 will be described as a molding target.

  As the constituent material of the core material 17, polyolefin (for example, polypropylene, high density polyethylene), polyamide, polystyrene, poly, which is a homopolymer or copolymer of olefins such as ethylene, propylene, butene, isoprene pentene, and methyl pentene. Acrylic derivatives such as vinyl chloride, polyacrylonitrile, ethylene-ethyl acrylate copolymer, polycarbonate, vinyl acetate copolymers such as ethylene-vinyl acetate copolymer, terpolymers such as ionomer, ethylene-propylene-dienes, ABS resin And thermoplastic resins such as polyolefin oxide and polyacetal. In addition, these may be used individually by 1 type, or may be used in combination of 2 or more types.

  In addition, foamed plastics (foamed polypropylene, foamed polyethylene, foamed polyurethane, foamed polystyrene (styrofoam), etc.) made by foaming polyolefin resin (polypropylene, polyethylene, etc.), polyurethane resin, polystyrene resin, etc. to provide heat insulation, etc. May be interposed and arranged as the core material 17.

  The constituent material of the core material 17 may contain an additive. Examples of the additive include silica, mica, talc, calcium carbonate, glass fiber, carbon fiber, and other inorganic fillers, plasticizers, stabilizers, Coloring agents, antistatic agents, flame retardants, foaming agents and the like can be mentioned.

  In addition, as a resin material which comprises the sheet-like resins 31 and 32, the same resin material as that described in the first embodiment can be used.

  In order to mold the resin molded product 1 having the above-described configuration, for example, in the contents described in “(4) Example of molding method” of the first embodiment, “(i) First step”, “( ii) After performing the “second step”, before clamping the male mold 41 and the female mold 42 (before performing “(iii) the third step”), the core material 17 is formed as described later. What is necessary is just to insert and attach to the sheet-like resin 31 and 32.

  FIG. 19 is a view showing a state in which the core member 17 is inserted between the molds (male mold 41 and female mold 42). As shown in FIG. 19, the core material 17 held by the suction disk R of a manipulator (not shown) is inserted between the two divided male molds 41 and female molds 42 from the side. Next, by moving the manipulator in a horizontal direction, for example, toward the female mold 42, the core material 17 is pressed against the sheet-shaped resin 32 adsorbed in the cavity of the female mold 42, whereby the core material 17 is formed into a sheet shape. It is welded to the resins 31 and 32.

  Next, the suction plate R is removed from the core member 17, and a manipulator (not shown) is pulled out between the two male dies 41 and the female dies 42 and clamped. FIG. 20 is a schematic view showing a state in which the sheet-like resins 31 and 32 are formed on the molds 41 and 42 in the second embodiment. In FIG. 17, the core material 17 is arranged on the sheet-like resin 32. It will be in the state.

  After that, as described in “(iii) third step” of the first embodiment, the male mold 41 and the female mold 42 are moved from the open position to the closed position by a mold driving device (not shown), Clamp the mold. As a result, the core material 17 welded to the sheet-like resin 32 of the female mold 42 is welded to the sheet-like resin 31 and the peripheral edges of the sheet-like resins 31 and 32 are welded to form a parting line. The FIG. 21 is a schematic diagram illustrating a state in which the mold is clamped in the second embodiment. In FIG. 18, the core material 17 is disposed in a portion corresponding to the hollow portion 16.

  Then, the male mold 41 and the female mold 42 are opened, and the completed resin molded product 1 is separated from the male mold 41 and the female mold 42 to remove burrs formed around the parting line.

(D) Variation of embodiment:
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the objects and effects. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. Further, the specific structure, shape, and the like in carrying out the present invention are not problematic as other structures, shapes, and the like as long as the objects and effects of the present invention can be achieved. The present invention is not limited to the above-described embodiments, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

  For example, in the above-described embodiment, as the mold (male mold 41, female mold 42), the side wall forming portions 51a, 51b, 52a, 52b are provided in two directions, and the non-wall forming portions 54a, 54b, 55a, 55b are provided in two directions. Arranged and explained as an example of the resin molded product 1 with the side walls 11, 12 as two sides and the side wall 11, 12 and the surface (wall) connecting the side edges of the connecting wall 13 is not formed. . On the other hand, as a mold (male mold 41, female mold 42), by adopting a configuration in which side wall forming portions 51a, 51b, 52a, 52b are arranged in four directions, a resin molded product 1 is formed in four directions. It is also possible to adopt a shape in which the side walls 11 and 12 are formed.

Further, in the above-described embodiment, the mold 74 in the above-described embodiment is fixed at a position slightly higher than the height of the inner fixed mold 73, and is retracted to the height of the inner fixed mold 73. However, it is possible to use a fixed mold that does not move, and a movable mold that can be retracted more than the height of the inner fixed mold 73, similar to the movable molds 92 and 93. It is good.
In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  INDUSTRIAL APPLICABILITY The present invention has industrial applicability as a molding means for suppressing the occurrence of pinholes, thin portions, etc. when molding a resin molded product having a U-shaped cross section that requires deep drawing. Is expensive.

DESCRIPTION OF SYMBOLS 1 ... Resin molded article 11, 12 ... Side wall 13 ... Connection wall 16 ... Hollow part 17 ... Core material 21a, 21b ... Hopper 22a, 22b ... Cylinder 23a, 23b ... Hydraulic motor 24a, 24b ... ... Accumulator 25a, 25b ... Plunger 26a, 26b ... T-die 27a, 27b ... Extrusion slit 28a, 28b, 28c, 28d ... Roller 31, 32 ... Sheet-like resin (sheet)
41 ...... Mold (male)
42 ...... Mold (female)
43 ... Core 44 ... Cavity 51a, 51b, 52a, 52b ... Side wall forming part 53a, 53b ... Connecting wall forming part 54a, 54b, 55a, 55b ... Wall non-forming part 61 ... Flat part 62 ... Male inclined surface portion 63 ...... Bank portion 64 ...... Flat portion 71 ...... Flat portion 72 ...... Female inclined surface portion 73 ...... Inside fixed mold frame 74 ...... Mold frame 90, 91, 92, 93 ...... Movable mold frame 81, 83 ...... Pinch-off part (male type)
82,84 …… Pinch-off part (female type)
S1, S2 ... Sealed space P, P1, P2 ... Extruder Q ... Mold clamping device R ... Suction plate X ... Molding device

Claims (7)

A manufacturing method of a resin molded product including a pair of side walls that are spaced apart from each other and a connecting wall that connects end portions of the side walls, and having a hollow portion inside, and having a U-shaped cross section,
A male mold having a convex core having a side wall forming portion and a connecting wall forming portion, which is present in the lower part of two sheet-like resins in a molten state, in which a melt-kneaded thermoplastic resin is formed into a sheet shape, A first step of placing between a female mold having a concave cavity with a side wall forming portion and a connecting wall forming portion;
One of the two sheet-like resins on the side close to the male mold is shaped into the shape of the core of the male mold using vacuum suction, and the one of the two sheet-shaped resins is the above-mentioned A second step of shaping one sheet closer to the female mold into the shape of the cavity of the female mold using vacuum suction;
In the third step of clamping the male mold and the female mold and bonding the two sheet-shaped resins so that the peripheral portions of the two sheet-shaped resins are welded to each other, the cross section is U-shaped. When molding shaped resin molded products,
On the outside of the pinch-off part of the male side wall forming part, a flat part having a flat shape is formed toward the outside of the male part, and the flat part is increased from the flat part to the outside of the male part. A method for producing a resin molded product, wherein a sloped male inclined surface portion is formed continuously over the longitudinal direction of the side wall forming portion.   2. The method for producing a resin molded product according to claim 1, wherein a width of the flat portion is 15 mm or more and an inclination angle of the male inclined surface portion is 20 ° to 80 °.   The method for producing a resin molded product according to claim 1, wherein the vacuum suction is performed at least one of a periphery of the pinch-off portion and the flat portion in the side wall forming portion. When forming a resin molded product having a U-shaped cross section in which a core material is disposed in a portion where the hollow portion is formed,
4. The method according to claim 1, wherein after the second step, the core material is welded to at least one of the shaped sheet-like resins, and the third step is performed. 5. Manufacturing method of resin molded product. A mold for manufacturing a resin molded product including a pair of side walls that are spaced apart from each other and a connecting wall that connects end portions of the side walls, having a hollow portion inside, and having a U-shaped cross section,
Having a convex core with side wall forming portions and connecting wall forming portions;
On the outer side of the pinch-off part in the side wall forming part, there is a flat part having a flat shape toward the outer side of the male mold, and a male having an inclination that increases from the flat part toward the outer side of the male mold. A mold for producing a resin molded product, wherein the mold inclined surface portion is formed continuously over the longitudinal direction of the side wall forming portion.   6. The mold for producing a resin molded product according to claim 5, wherein a width of the flat portion is 15 mm or more and an inclination angle of the male inclined surface portion is 20 to 80 degrees.   The mold for producing a resin molded product according to claim 6, wherein a suction part for performing vacuum suction is formed on at least one of the periphery of the pinch-off part and the flat part in the side wall forming part.

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