JP5748105B2 - Method for producing molded structure and mold - Google Patents

Description

  The present invention relates to a method for manufacturing a molded structure and a mold.

  Conventionally, as a molded structure used for a door trim or the like, a structure including a base material including a thermoplastic resin and a molded body (an attachment boss, a bracket, or the like) joined to the base material is known (for example, the following patents) Reference 1). As a method for producing such a molded structure, the following method is known. First, a base material is formed by pressing a preboard softened and melted by heating with a forming die (base material forming step). Next, in a state where the base material is pressed, a molded body is formed on the base material by injecting molten resin into a cavity (molding space) formed in the mold (molded body forming step). Thereby, a molded object is shape | molded in the state joined to the base material.

JP 2009-113244 A

  However, in the manufacturing method described above, there is a concern that when the preboard is pressed by the mold, the material including the thermoplastic resin constituting the preboard (base material) enters the cavity. If a material containing a thermoplastic resin (a part of the base material) enters the cavity, the molten resin may be prevented from flowing when the molten resin is injected into the cavity in the next step (molded body molding step). . As a result, a situation occurs in which a part of the molded body is not molded, and there is a concern that the quality of the molded body may deteriorate.

  This invention is completed based on the above situations, Comprising: It aims at providing the manufacturing method of the molded structure which can make the quality of a molded object higher. Moreover, it aims at providing the shaping | molding die which can shape | mold such a molded structure.

  In order to solve the above problems, a method for producing a molded structure according to the present invention is a method for producing a molded structure including a base material and a molded body molded on the base material, and includes a fiber and a heat Of the pair of molds, in a state in which the substrate is pressed by the pair of molds, and a substrate molding step of molding the substrate by press-molding a pre-board containing a plastic resin with a pair of molds, A molded body molding step of molding the molded body in a state of being bonded to the base material by injecting a molten resin into a cavity formed on the contact surface with the base material in one mold, In the pair of molds, at least one of the abutment surface of the one mold or the abutment surface of the other mold with the base material has a friction resistance portion having a higher frictional resistance than the surroundings. Features that are formed along A.

  According to the present invention, in the base material forming step, when the preboard is pressed by the forming die, a part of the preboard (base material) is pressed. Part of the pressed preboard (fibers and thermoplastic resin constituting the preboard) may flow toward the cavity and enter the cavity. In the present invention, a frictional resistance portion having a higher frictional resistance than the surroundings extends along the cavity on the contact surface with the base material in one mold or the other mold. With such a configuration, in a part of the preboard that flows toward the cavity, the fibers constituting the preboard are caught by the frictional resistance portion, and the flow is hindered. Thereby, the situation where a part of preboard enters into a cavity can be suppressed. For this reason, when the molten resin is injected into the cavity in the molded body forming step, which is the next step, it is possible to suppress a situation in which the flow of the molten resin is hindered. As a result, a situation in which a part of the molded body is not molded can be more reliably suppressed, and the quality of the molded body can be further increased.

  In the above configuration, the cavity includes a molded body cavity having a shape corresponding to the shape of the molded body, and a resin circulation portion that communicates with the molded body cavity and allows the molten resin to flow to the molded body cavity. And the frictional resistance portion may be formed along the resin circulation portion.

  According to this invention, the situation where a part of preboard penetrate | invades into a resin distribution part can be suppressed by forming a friction resistance part in the form along a resin distribution part. Thereby, the situation where the resin distribution part is blocked by the preboard (base material) can be suppressed, and the molten resin can be more reliably distributed to the molded body cavity.

  The arithmetic average roughness of the frictional resistance portion may be a value larger than the arithmetic average roughness around the frictional resistance portion on the one surface.

  According to the present invention, the frictional resistance portion can be formed by making the arithmetic average roughness larger than the arithmetic average roughness around the arithmetic average roughness. With such a configuration, the frictional resistance portion can be easily formed by a relatively simple method of adjusting the surface roughness.

  Next, in order to solve the above-mentioned problems, a molding die of the present invention is a molding die for molding a molded structure including a base material and a molded body molded on the base material. A pair of molds capable of molding the base material by press-molding a preboard containing fibers and a thermoplastic resin, and in any one of the pair of molds, a contact surface with the base material Is formed with a cavity for molding the molded body, and in the pair of molds, at least one surface of the contact surface of the one mold or the contact surface of the other mold with the substrate. In addition, a frictional resistance portion having a higher frictional resistance than the surroundings may be formed along the cavity.

  In the present invention, frictional resistance portions having higher frictional resistance than the surroundings are extended along the cavity on the contact surfaces of the pair of molds with the base material. If it is set as such a structure, the flow of a preboard will be prevented because the fiber of a preboard is caught in a friction resistance part. Thereby, when a preboard is press-molded, a situation in which a part of the preboard enters the cavity can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the molded structure which can make the quality of a molded object higher can be provided. Moreover, the shaping | molding die which can shape | mold such a molded structure can be provided.

The perspective view which shows the shaping | molding structure which concerns on one Embodiment of this invention. Sectional drawing which shows the manufacturing method and shaping | molding die which manufacture the shaping | molding structure of FIG. 1 (state before a trim board is shape | molded) Sectional drawing which shows a base-material formation process (corresponding to the figure cut in the AA line of Drawing 1) Sectional drawing which shows the state which injected molten resin from the state of FIG. 3 to the attachment boss | molding space (figure which shows a molded object formation process) Sectional drawing which expands and shows a runner vicinity in a base-material formation process (corresponding to the figure cut by the BB line in FIG. 3) The perspective view which expands and shows the runner vicinity in the shaping | molding die of this embodiment. Sectional drawing which shows the state which pressed the preboard in the base-material formation process In this embodiment, the expanded sectional view which shows typically the contact location of a trim board and a friction resistance part Sectional view showing a comparative example In the comparative example, an enlarged cross-sectional view schematically showing a contact portion between the trim board and the friction resistance portion

  An embodiment of the present invention will be described with reference to FIGS. The door trim 10 (molded structure) of this embodiment is attached to a vehicle door. As shown in FIG. 1, as shown in FIG. 1, a trim board 20 (base material) and an attachment boss 30 ( Molded body, functional part).

  The trim board 20 has a substantially flat plate shape, and is formed by press-molding a mat-like preboard P1 (see FIG. 2) formed by impregnating fibers with polypropylene, which is a thermoplastic resin. The trim board 20 is compressed (thin plate thickness is reduced) by, for example, press molding, and has a higher density than the pre-board P1. In addition, as a fiber used for the preboard P1 (trim board 20), for example, a wood fiber obtained by weaving wood or the like, a bast plant fiber such as kenaf, or the like is used, but the type of the fiber is limited to this. Not.

  In the trim board 20, polypropylene plays a role as a binder for connecting fibers. Moreover, you may form the trim board 20 with the mixture of thermoplastic resins other than polypropylene, such as a polyethylene terephthalate, and a fiber.

  The mounting boss 30 is made of, for example, polypropylene, which is a thermoplastic resin, and is formed so as to protrude from the back surface (surface on the vehicle interior side) of the trim board 20 as shown in FIG. The mounting boss 30 is joined to the trim board 20. The mounting boss 30 has a cylindrical main body 31. The main body 31 functions, for example, as an attachment part for components (for example, door pockets, ornaments, armrests, etc.) attached to the door trim 10.

  The mounting boss 30 has a plurality of reinforcing ribs 32 extending from the base end of the main body 31 (near the joint portion with the trim board 20). The reinforcing rib 32 has a function of increasing the bonding strength of the main body 31 to the trim board 20.

  The mounting boss 30 is molded by injecting molten resin onto the trim board 20 in a state where the trim board 20 is set on the molding die 50 (details will be described later). That is, the mounting boss 30 is joined to the trim board 20 at the same time as molding.

  A plurality (two in this embodiment) of mounting bosses 30 are formed on the trim board 20. Two mounting bosses 30 (denoted by reference numerals 30A and 30B in the following description) are respectively molded by molten resin injected from one gate 62 (see FIG. 4) provided in the molding die 50 (details). Will be described later).

  Further, as shown in FIG. 1, a first rib 21 is formed on the rear surface of the trim board 20 so as to extend so as to be connected to one of the two mounting bosses 30 </ b> A and 30 </ b> B. The first rib 21 is formed by cooling the molten resin filled in the runner 66 (see FIG. 2, details will be described later) when forming the mounting boss 30A (trace of the runner 66). It is. Note that the connecting portion 21A of the first rib 21 with the mounting boss 30A has a structure in which the protruding height increases toward the mounting boss 30A.

  Further, as shown in FIG. 1, a second rib 22 is extended on the rear surface of the trim board 20 so as to connect the two mounting bosses 30A and 30B. The second rib 22 is formed by cooling the molten resin filled in the runner 67 (see FIG. 2, details will be described later) when the mounting boss 30B is formed (trace of the runner 67). It is.

  In the present embodiment, a non-woven fabric (not shown) may be attached to the back surface of the trim board 20 (more specifically, between the ribs 21 and 22 and the back surface of the trim board 20). By sticking a non-woven fabric having a flat surface on the surface of the trim board 20 having a relatively rough surface shape, the surface of the non-woven fabric can easily flow through the molten resin. That is, the molten resin can easily flow through the runners 66 and 67.

  Next, the shaping | molding apparatus 40 which manufactures the door trim 10 is demonstrated. The molding apparatus 40 in this embodiment is an injection molding apparatus, and includes an injection apparatus 41 and a molding die 50 including an upper mold 51 and a lower mold 61 (a pair of molds). The injection device 41 is, for example, a screw type, and is provided in the lower die 61 in this embodiment.

  The upper mold 51 is a movable mold that can move with respect to the lower mold 61 (fixed mold) by a driving device (not shown) (for example, an electric motor, an air cylinder, a hydraulic cylinder, or the like). The upper mold 51 can be closed and opened by moving the upper mold 51 close to and away from the lower mold 61. In the following description, the state where the upper mold 51 and the lower mold 61 are closed is the closed state (the state shown in FIGS. 3 and 4), and the state where the upper mold 51 and the lower mold 61 are opened is the open state (FIG. 2). ) State.

  The lower mold 61 has a shape in which a surface 61 </ b> A facing the upper mold 51 protrudes toward the upper mold 51. Further, the upper mold 51 has a shape in which the facing surface 51 </ b> A facing the lower mold 61 is recessed corresponding to the shape of the lower mold 61. As shown in FIG. 3, the upper mold 51 is disposed opposite to the lower mold 61 with a distance equal to the plate thickness of the trim board 20 in the closed state.

  That is, in the closed state, a base material forming space S1 for forming the trim board 20 is formed between the upper die 51 and the lower die 61. Thus, when the preboard P1 is pressed by the upper mold 51 and the lower mold 61, the preboard P1 is compressed into a shape corresponding to the shape of the base material forming space S1, and the trim board 20 is formed.

  A gate 62 that is a resin injection port for the runner 66 is provided inside the lower mold 61. The molten resin can be injected from the injection device 41 to the runner 66 through the gate 62. The lower die 61 is formed with an attachment boss forming space S2 for forming the attachment boss 30A and an attachment boss forming space S3 for forming the attachment boss 30B.

  The runner 66 is formed in the lower mold 61 so as to communicate the gate 62 and the mounting boss forming space S2. Accordingly, the molten resin can be injected from the injection device 41 (and thus the gate 62) into the mounting boss molding space S2 through the runner 66. Moreover, the depth of the connection portion between the runner 66 and the mounting boss forming space S2 increases toward the mounting boss forming space S2. As a result, the molten resin easily flows from the runner 66 to the mounting boss molding space S2.

  The runner 67 (cavity, resin distribution part) is formed in the lower mold 61 so as to communicate the mounting boss molding space S2 and the mounting boss molding space S3 (molded body cavity). Thus, the molten resin injected into the mounting boss molding space S2 is distributed through the runner 67 to the mounting boss molding space S3. Thus, in this embodiment, it is possible to inject the molten resin into each of the mounting boss molding space S2 and the mounting boss molding space S3 with only one injection device 41 for injecting the molten resin. Two mounting bosses 30A and 30B can be formed with a simple configuration.

  Further, the mounting boss molding spaces S2 and S3 are respectively formed on a surface 61A of the lower mold 61 facing the upper mold 51 (a contact surface with the base material in one mold). That is, the mounting boss molding spaces S2 and S3 have openings to the outside. In the closed state, the base material forming space S1 is communicated with each of the mounting boss forming spaces S2 and S3 as shown in FIG. The communicating portion between the base material forming space S1 and the mounting boss forming spaces S2, S3 corresponds to the joint portion between the trim board 20 and the mounting bosses 30A, 30B.

  The mounting boss molding space S2 has a main body molding space S21 for molding the main body 31 of the mounting boss 30A, and a plurality of reinforcing rib molding spaces S22 for molding the reinforcing ribs 32 in the mounting boss 30A. Yes. The mounting boss molding space S3 includes a main body molding space S31 for molding the main body 31 of the mounting boss 30B and a plurality of reinforcing rib molding spaces S32 for molding the reinforcing ribs 32 in the mounting boss 30B. doing. That is, the main body portion forming spaces S21 and S31 have a concave shape corresponding to the cylindrical shape of the main body portion 31, and the reinforcing rib forming spaces S22 and S32 have a groove shape corresponding to the plate shape of the reinforcing rib 32. ing.

  As shown in FIGS. 5 and 6, the runner 67 is formed on the facing surface 61 </ b> A (the contact surface with the base material) of the lower die 61 facing the upper die 51. 63. In other words, the runner 67 is formed by recessing the protruding end surface 63A of the protruding portion 63. As shown in FIG. 5, the runner 67 has a shape in which the opening width increases as it goes upward (opening side). As a result, the second rib 22 can be easily removed from the runner 67.

  In the present embodiment, the projecting portion 63 has a substantially trapezoidal shape in cross section as shown in FIG. 6, and has a projecting end surface 63A and inclined surfaces 63B and 63C extending from the projecting end surface 63A, respectively. And the runner 67 is formed in the form in which the protrusion end surface 63A of the protrusion 63 is recessed.

  In the present embodiment, the runners 66 and 67 are recessed in a surface 61A facing the upper mold 51 in the lower mold 61 (a contact surface with the base material in one mold). That is, the runners 66 and 67 are opened upward (upper mold 51 side). Thereby, runners 66 and 67 can be easily formed by, for example, cutting.

  The protruding end surface 63A and the inclined surfaces 63B and 63C of the protruding portion 63 are formed with a friction resistance portion 64 having a higher friction resistance than the surroundings (surfaces other than the protruding end surface 63A and the inclined surfaces 63B and 63C of the facing surface 61A). Has been. Specifically, the protruding end surface 63A and the inclined surfaces 63B and 63C have a surface roughness larger than the surroundings (surfaces other than the protruding end surface 63A and the inclined surfaces 63B and 63C on the facing surface 61A). The frictional resistance portion 64 is shown in a satin pattern in FIG.

  The “surface roughness” mentioned here can be defined by, for example, arithmetic average roughness Ra. In the present embodiment, the arithmetic average roughness Ra of the projecting end surface 63A and the inclined surfaces 63B and 63C is set, for example, in the range of 150 μm to 400 μm. On the other hand, the arithmetic average roughness Ra of the opposing surface 61A other than the protruding end surface 63A and the inclined surfaces 63B and 63C is, for example, about 1.6 μm.

  In the present embodiment, the friction resistance portion 64 can be formed by performing surface treatment such as knurling or shot blasting on the protruding end surface 63A and the inclined surfaces 63B and 63C to increase the surface roughness. . In addition, the formation method of the frictional resistance part 64 is not limited to the said surface treatment process.

  In the present embodiment, as shown in FIG. 6, the frictional resistance portions 64 are formed so as to sandwich both sides of the runner 67. Further, the frictional resistance portion 64 extends along the entire length of the runner 67 along the runner 67.

  Next, the manufacturing method of the door trim 10 by the shaping | molding apparatus 40 is demonstrated. The manufacturing method of the door trim 10 according to the present embodiment includes a preboard forming process for forming the preboard P1, a base material forming process (base material arranging process) for forming the trim board 20 from the preboard P1, and the mounting boss 30 on the trim board 20. A molded body molding step for molding the molded body.

<Preboard molding process>
In the pre-board molding process, for example, a mat material in which fibers and polypropylene (thermoplastic resin) are mixed is heated and press-molded, and this is made longer than a predetermined length (for example, the length dimension of the trim board 20 after molding). The pre-board P1 is formed by cutting along the dimension (1). Note that the preboard P1 is heated immediately after molding, and the internal thermoplastic resin (polypropylene) is in a softened state.

<Base material forming step (base material arranging step)>
First, as shown in FIG. 2, the preboard P1 molded by the preboard molding process is heated again to the extent that the polypropylene is melted and softened, and is set between the upper mold 51 and the lower mold 61 in the open state (see FIG. 2 and FIG. 2). The state of FIG. Thereafter, as shown in FIGS. 3 and 7, the upper die 51 and the lower die 61 are closed to press the preboard P <b> 1 by the forming die 50. At the same time, the peripheral end portion P2 (unnecessary outer periphery portion) of the preboard P1 is cut off by shearing of both molds 51 and 61. As a result, the trim board 20 is molded by the mold 50.

  As shown in FIGS. 5 and 7, in the pre-board P <b> 1, the portion pressed by the protruding portion 63 is compressed more than the surrounding portions. Thereby, in the trim board 20, the part pressed by the protrusion part 63 is made into the high-density part 24 whose density is high compared with the surrounding part.

  Further, the molded trim board 20 is arranged in the molding die 50 in a state where the openings of the mounting boss molding spaces S2, S3 are closed. That is, this process is a process of forming the trim board 20 and arranging the trim board 20 on the molding die 50 (base material arrangement process) in preparation for the next molded body molding process. The mounting boss forming spaces S2 and S3 are formed as closed spaces by being closed by the trim board 20.

<Molded body forming process>
Next, in a state where the trim board 20 is pressed by the molding die 50 (a state where the openings of the mounting boss molding spaces S2 and S3 are closed by the trim board 20, the state shown in FIG. 3), the injection device 41 melts from the gate 62. Resin is injected into the runner 66. At this time, the temperature of the trim board 20 is set to a temperature at which the polypropylene inside the trim board 20 is softened.

  As shown in FIG. 4, the molten resin injected into the runner 66 flows and is supplied to the mounting boss forming space S <b> 2 through the runner 66. In addition, the molten resin supplied into the mounting boss molding space S2 flows through the runner 67 and flows into the mounting boss molding space S3. Thereby, the mounting boss molding space S2 and the mounting boss molding space S3 are filled with the molten resin.

  In the process of filling the mounting boss molding spaces S2 and S3 with the molten resin, the molten resin penetrates into the fibers instead of the softened polypropylene while pushing the softened polypropylene inside the trim board 20 upward. At the same time, the molten resin that has penetrated into the fiber mixes with the softened polypropylene inside the trim board 20 and becomes a unitary (mixed).

  Thus, both the mounting boss molding spaces S2 and S3 are filled with the molten resin, and then the molten resin is cooled, so that the mounting bosses 30A and 30B are joined to the trim board 20 as shown in FIG. Molded with. In addition, the molten resin with which the runner 66 and the runner 67 were filled is formed as the 1st rib 21 and the 2nd rib 22 on the trim board 20 by being cooled, respectively. Thereafter, the upper die 51 and the lower die 61 are opened, and the door trim 10 in a state where the mounting boss 30 is integrally joined to the trim board 20 is removed from the mold, whereby the manufacture of the door trim 10 is completed.

  Next, the effect of this embodiment will be described. In order to explain the effect of the present embodiment, first, a comparative example of FIG. 9 will be described. As shown in FIG. 9, when the preboard P1 is pressed by the upper mold 51 and the lower mold 61 in the base material forming step, a part of the preboard P1 is pressed.

  Temporarily, in the case of a configuration that does not include the frictional resistance portion 64 as in the present embodiment, a part P3 of the pressed preboard P1 (fibers and thermoplastic resin constituting the preboard P1) flows toward the runner 67. There is a risk of entering the runner 67. In addition, the flow of the fiber and thermoplastic resin which comprise the preboard P1 at this time is shown by the arrow lines f1 and f2 in FIG.

  A part P3 of the preboard P1 entering the runner 67 blocks a part of the runner 67. For this reason, it becomes difficult for the molten resin for molding the mounting boss 30 </ b> B to flow in the runner 67 in the molded body molding step. In particular, the fiber is considered to be the main factor that hinders the flow of the molten resin because the fluidity in the runner 67 is low. Accordingly, there is a concern that the molten resin injected from the gate 62 is not filled into the mounting boss molding space S3 and a part of the mounting boss 30B is not molded.

  On the other hand, according to the present embodiment, the friction resistance portion 64 having a higher friction resistance than the surroundings extends along the runner 67 on the surface 61A of the lower mold 61 facing the upper mold 51. With such a configuration, in a part of the preboard P1 that flows toward the runner 67, the fibers 26 constituting the preboard P1 are caught by the unevenness of the frictional resistance portion 64, thereby preventing the flow (see FIG. 8). ).

  Thereby, the situation where a part of preboard P1 enters into the runner 67 can be suppressed. For this reason, when the molten resin is injected from the injection device 41 to the runner 67 in the molded body forming step, which is the next step, it is possible to suppress a situation in which the flow of the molten resin is hindered. As a result, a situation in which a part of the mounting boss 30B is not molded can be more reliably suppressed, and the quality of the mounting boss 30B can be further improved.

  The mounting boss forming space S3 has a shape corresponding to the shape of the mounting boss 30B, and the runner 67 communicates with the mounting boss forming space S3 and allows the molten resin to flow through the mounting boss forming space S3. The frictional resistance portion 64 is formed along the runner 67.

  According to the present embodiment, by forming the friction resistance portion 64 along the runner 67, it is possible to suppress a situation where a part of the preboard P <b> 1 enters the runner 67. Thereby, the situation where the runner 67 is blocked by the preboard P1 (trim board 20) can be suppressed, and the molten resin can be more reliably distributed to the mounting boss molding space S3.

  Further, the depth of the runner 67 is substantially the same value as the height of the second rib 22. If the second rib 22 is high, for example, the second rib 22 may interfere with the vehicle door when the door trim 10 is attached to the vehicle door. For this reason, in order to make the 2nd rib 22 low, it is preferable to make the depth of the runner 67 small.

  However, if the depth of the runner 67 is small, the fluidity of the molten resin in the runner 67 is greatly reduced by only a small amount of the preboard P1 entering. For this reason, it is necessary to pay particular attention to the entry of the preboard P1 into the runner 67. In this regard, in this embodiment, by forming the frictional resistance portion 64 along the runner 67 (in an adjacent form), the entry of the preboard P1 into the runner 67 can be effectively suppressed.

  Further, the arithmetic average roughness of the frictional resistance portion 64 is set to a value larger than the arithmetic average roughness around the frictional resistance portion 64. According to the present embodiment, the frictional resistance portion 64 can be formed by making the arithmetic average roughness larger than the surrounding arithmetic average roughness. With this configuration, the frictional resistance portion 64 can be easily formed by a relatively simple method such as adjusting the surface roughness.

  In the present embodiment, the arithmetic average roughness Ra of the projecting end surface 63A and the inclined surfaces 63B and 63C (friction resistance portion 64) is set in the range of 150 μm or more and 400 μm or less, for example. On the other hand, when the fibers 26 included in the preboard P1 are, for example, kenaf fibers, the thickness (outer diameter) is, for example, about 60 to 120 μm. Thereby, by setting the arithmetic average roughness Ra of the frictional resistance portion 64 to 150 μm or more sufficiently larger than 120 μm, most of the fibers 26 are fine on the surface of the frictional resistance portion 64 as shown in FIG. It becomes easy to get caught in irregularities. Thereby, the situation where a part of pre board P1 flows toward runner 67 can be controlled more certainly. When the arithmetic average roughness Ra of the projecting end surface 63A (and the inclined surfaces 63B and 63C) is small, the unevenness of the surface is fine, so that the fibers 26 included in the preboard P1 are not easily caught on the surface (see FIG. 10).

  On the other hand, when the arithmetic average roughness Ra of the frictional resistance portion 64 is 400 μm or more, the preboard P1 (fiber 26) is easily caught and the flow to the runner 67 can be suppressed, but the surface of the frictional resistance portion 64 and the preboard P1 The gap generated between the two becomes large. As a result, the molten resin injected and flowed to the runner 67 leaks to the back surface of the trim board 20 through this gap, and the amount of resin used for the mounting boss 30 is reduced, thereby causing problems such as lack of thickness. There is a fear. Further, it is conceivable that the surface of the friction resistance portion 64 becomes rough, so that the trace of the friction resistance portion 64 remains on the surface of the trim board 20 and affects the product quality. From the above, it is preferable to set the arithmetic average roughness Ra of the frictional resistance portion 64 in a range of 150 μm or more and 400 μm or less.

  Further, according to the present embodiment, the protruding portion 63 is formed on the lower mold 61. For this reason, in the pre-board P1, the amount pressed by the protrusion 63 is larger than the surrounding portion (see FIGS. 5 and 7). Thereby, in the trim board 20, the part pressed by the protrusion part 63 is made into the high-density part 24 whose density is high compared with the surrounding part.

  With such a configuration, when the molten resin is injected into the runner 67 in the molded body molding step, the high-density portion 24 has a higher density than the configuration having the same density as the surrounding portions. It becomes difficult for the molten resin to penetrate the portion 24. Moreover, the high density part 24 is pressed by the protrusion part 63 with a pressure higher than another location. For this reason, it becomes difficult for the molten resin to enter between the high density portion 24 and the protruding portion 63. From the above, it is possible to suppress the situation where the molten resin oozes out (appears) on the surface of the high density portion 24. Thereby, the situation where the joining area of the trim board 20 and the 2nd rib 22 (rib formed on the trim board 20 with the molten resin with which the runner 67 was filled) increases can be suppressed.

  In general, when the bonding area between the trim board 20 and the second rib 22 is increased, the influence on the trim board 20 is increased when the second rib 22 is thermally contracted. For example, there is a concern that the design surface (surface opposite to the surface on which the second rib 22 is formed) of the trim board 20 may be uneven due to heat shrinkage of the second rib 22. In this respect, in the present embodiment, by providing the protrusion 63, it is possible to suppress a situation in which the joining area between the trim board 20 and the second rib 22 increases, and it is possible to further improve the quality of the trim board 20. .

  Thus, in this embodiment, the preboard P1 is pressed more strongly in the vicinity of the protrusion 63. That is, in the vicinity of the protrusion 63, the preboard P1 is more strongly compressed, and as a result, more fibers and thermoplastic resin are likely to face the runner 67.

  Therefore, in the present embodiment, the frictional resistance portion 64 is formed in the protruding portion 63 (where the preboard P1 is pressed more strongly). Thereby, the situation where a part of preboard P1 penetrate | invades into the runner 67 can be suppressed effectively.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, the door trim 10 is exemplified as the molded structure, and the trim board 20 is exemplified as the base material. However, the present invention is not limited to this. The molded structure includes a base material containing a thermoplastic resin such as an ornament base material constituting the door trim 10, a seat backboard, and a shielding material for concealing a functional product of the seat, and a molten resin is injected onto the base material. What is necessary is just to provide the molded object shape | molded by shape | molding. The door trim 10 may be provided with parts other than the mounting boss 30.

  (2) In the said embodiment, although the attachment boss | hub 30 was illustrated as a molded object, it is not limited to this. For example, a bracket that can be attached to a door inner panel can be exemplified as the molded body.

  (3) The number of mounting bosses 30 is not limited to the number illustrated in the above embodiment (two) and can be changed as appropriate. For example, only one mounting boss 30 may be formed on the trim board 20, or three or more may be formed.

  (4) The shapes of the plurality of molded bodies molded on the substrate may be different from each other. For example, the two mounting bosses 30A and 30B may have different shapes.

  (5) In the above embodiment, the configuration in which the frictional resistance portions 64 are formed on both sides of the runner 67 is exemplified, but the present invention is not limited to this. The friction resistance portion 64 may be formed only on one side of the runner 67.

  (6) In the said embodiment, although the runner 67 (resin flow part) was illustrated as a cavity to which the frictional resistance part 64 adjoins, it is not limited to this. The frictional resistance portion 64 may be anything that is adjacent to the cavity for molding the molded body. For example, the frictional resistance portion 64 may be formed adjacent to the mounting boss forming spaces S2, S3 for forming the mounting boss 30.

  (7) In the above embodiment, the configuration in which the runner 67 and the frictional resistance portion 64 are provided in the protruding portion 63 in the lower mold 61 is exemplified, but the configuration is not limited thereto. The mold 50 may not have the protruding portion 63. Further, the frictional resistance portion 64 may be provided at a place other than the protruding portion 63.

  (8) The arithmetic average roughness Ra of the surface of the lower mold 61 is not limited to the values exemplified in the above embodiment, and can be changed as appropriate.

  (9) In the above embodiment, the configuration in which the frictional resistance portion 64 is formed at a location adjacent to the runner 67 in the lower mold 61 is illustrated, but the present invention is not limited to this. The frictional resistance portion 64 only needs to be formed along the runner 67. For example, the friction resistance portion 64 may be formed at a position facing the runner 67 in the surface 51A facing the trim board 20 in the upper mold 51 (contact surface with the base material in the other mold).

  (10) In the above-described embodiment, the configuration in which the protrusion 63 is provided at the place where the runner 67 is formed is illustrated, but the present invention is not limited to this. For example, the protrusion 63 may be provided at a place where the runner 66 is formed.

  (11) The materials of the trim board 20 and the mounting boss 30 are not limited to those exemplified in the above embodiment, and can be changed as appropriate.

  (12) In the above embodiment, the upper mold 51 is a movable mold and the lower mold 61 is a fixed mold. However, the present invention is not limited to this. Moreover, the structure for shape | molding attachment boss | hubs 30, such as runner 67, may be provided in the upper mold | type 51, for example.

  (13) In the above embodiment, the configuration in which the frictional resistance portion 64 is formed by adjusting the surface roughness of the lower mold 61 is illustrated, but the present invention is not limited to this. The frictional resistance portion 64 only needs to be a location where the frictional resistance is higher than its surroundings, and its formation means can be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Door trim (molded structure), 20 ... Trim board (base material), 26 ... Fiber, 30 ... Mounting boss (molded body), 50 ... Mold, 51 ... Upper mold (comprising a pair of molds), 61 ... Lower mold (one of a pair of molds), 61A ... the surface facing the upper mold in the lower mold (contact surface with one substrate in one mold, one surface), 64 ... frictional resistance portion, 67 ... Runner (resin distribution part, part of cavity), P1 ... Pre-board, S3 ... Mounting boss molding space (molded body cavity)

Claims (4)

A method for producing a molded structure comprising: a base material; and a molded body molded on the base material,
A base material molding step for molding the base material by press molding a preboard containing fibers and a thermoplastic resin with a pair of molds;
In the state where the base material is pressed by the pair of molds, the molding is performed by injecting a molten resin into a cavity formed on a contact surface of the one mold with the base material in one of the pair of molds. A molded body molding step for molding a body in a state of being bonded to the base material,
In the pair of molds, at least one of the abutment surface of the one mold or the abutment surface of the other mold with the base material has a friction resistance portion having a higher frictional resistance than the surroundings. A method for producing a molded structure, characterized by being formed along a cavity. The cavity has a molded body cavity that has a shape corresponding to the shape of the molded body, and a resin circulation portion that communicates with the molded body cavity and allows the molten resin to flow to the molded body cavity.
The method for manufacturing a molded structure according to claim 1, wherein the frictional resistance portion is formed along the resin circulation portion.   3. The molding structure according to claim 1, wherein the arithmetic average roughness of the frictional resistance portion is a value larger than the arithmetic average roughness around the frictional resistance portion on the one surface. Body manufacturing method. A molding die for molding a molded structure including a base material and a molded body molded on the base material,
A pair of molds capable of molding the base material by press molding a preboard containing fibers and a thermoplastic resin,
In any one of the pair of molds, a cavity for molding the molded body is formed on the contact surface with the base material,
In the pair of molds, at least one of the abutment surface of the one mold or the abutment surface of the other mold with the base material has a friction resistance portion having a higher frictional resistance than the surroundings. A molding die characterized by being formed along the line.

Images