Resin molded product, molding apparatus, molding method, and die

Abstract

To provide a resin molded product which is molded in a shortened time.SOLUTION: The resin molded product is molded from plural resins and includes a runner with a joint at which a first resin and a second resin meet. The joint includes a first joint molded from the first resin and a second joint molded from the second resin, and the first joint is formed in a concave shape including a wall coming in contact with part of the second joint.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a resin molded product, a molding apparatus, a molding method, and a mold. [Background technology]

[0002] For example, in a multi-colored molded product molded using a plurality of resins, different resins may be connected to each other at the runner portion. Patent Document 1 describes a molding device for molding such a multi-colored molded product. In the molding device described in Patent Document 1, a partition member is provided in the runner groove of the mold, and the partition member blocks the flow of the primary molding resin flowing from one side of the runner groove. After the primary molding resin hardens, a secondary molding resin different from the primary molding resin flows from the other side of the runner groove. At this time, the partition member is pushed down outside the runner groove by the flow pressure of the secondary molding resin, so that the secondary molding resin flows into the position where the partition member was located and is welded to the primary molding resin. Then, a multi-colored molded product is formed, which is made of the primary molding resin and the secondary molding resin of a color different from the primary molding resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-258082 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the molding device described in Patent Document 1, if the secondary molding resin reaches the partition member before the primary molding resin hardens, the primary molding resin and the secondary molding resin may mix at the location where the partition member was located. Therefore, the injection time must be adjusted by delaying the injection of the secondary molding resin so that the secondary molding resin reaches the partition member after the primary molding resin hardens, which takes a long time for molding.

[0005] The present invention provides a resin molded product in which the molding time is shortened. [Means for solving the problem]

[0006] According to one aspect of the present invention, for example, there is provided a resin molded product molded from a plurality of resins and including a joint portion where a first resin and a second resin join on a runner, the joint portion including a first joint portion molded from the first resin and a second joint portion molded from the second resin, the first joint portion being formed in a concave shape having a wall portion in contact with a portion of the second joint portion. Effect of the Invention

[0007] According to the present invention, it is possible to provide a resin molded product in which the molding time is shortened. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of a molding device according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] 4A is a perspective view of a main portion of the runner groove, FIG. 4B is a perspective view of a main portion of the runner groove showing a state in which a partition member is retracted, and FIG. 4C is an enlarged perspective view of the partition member in the runner groove. [Figure 4] 1A is a perspective view of a runner of a resin molding according to a first embodiment of the present invention, and FIG. [Diagram 5] (A) is a perspective view of the runner of the resin molded product in Figure 4, and (B) is a cross-sectional view. [Figure 6] 1A is a cross-sectional view of the mold after completion of injection of the first resin, and FIG. 1B is a cross-sectional view of the mold after completion of injection of the second resin. [Figure 7] FIG. 4 is a cross-sectional view of a main portion of a runner groove according to a second embodiment of the present invention. [Figure 8] 1A is a cross-sectional view of the mold after completion of injection of the first resin, and FIG. 1B is a cross-sectional view of the mold after completion of injection of the second resin. [Figure 9]6A and 6B are a perspective view and a cross-sectional view, respectively, of a runner of a resin molded product according to a second embodiment of the present invention. [Figure 10] (A) is a perspective view of the runner of the resin molded product in Figure 9, and (B) is a cross-sectional view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same elements. In each drawing, the up, down, left and right directions relative to the paper surface will be used in the description in the text as the up, down, left and right directions of the device in this embodiment. In the embodiment described below, the present invention will be exemplified by resin materials of different colors as molding materials, but is not limited to this, and can be applied to molding materials of different materials (thermoplastic resins such as polystyrene, polyethylene, ABS, thermosetting resins, metals, etc.), resins of different transparencies, etc.

[0010] First Embodiment The molding device 1 includes a known injection device (not shown) and is made up of a movable mold body 2 attached to the moving side of the injection device and a fixed mold body 3 attached to the fixed side of the injection device. Figure 1 is a cross-sectional view of the entire molding device 1 in which the movable mold body 2 is joined to the fixed mold body 3.

[0011] The movable mold body 2 comprises a male mold mounting plate 6 for mounting a male mold (movable mold) 5, a fixed base 7 for fixing the male mold mounting plate 6, a movable side mounting plate 9 attached to the injection device, and spacers 10 provided on both sides between the fixed base 7 and the movable side mounting plate 9. Reference numerals 11 and 12 denote recesses for connecting injection nozzles for injecting molding resin materials of different colors through runner grooves 15 and 16 into a molding mold 18 formed between the male mold 5 and a female mold 51, which will be described later.

[0012] A chamber 19 is formed in the fixed base 7, and a push-out plate 20 is movably provided in this chamber 19. A plurality of knock-out pins 21 are implanted in this push-out plate 20. Each knock-out pin 21 penetrates the male mold mounting plate 6, the male mold 5, etc., and its tip appears and disappears in the molding die 18 and the runner grooves 15, 16, so as to push out a multi-color molded product 24 molded in the molding die 18 and a multi-color runner R molded in the runner grooves 15, 16, as described later. The push-out plate 20 is fixed to a pressing shaft 25 inserted through holes 22, 23 formed in approximately the center of the fixed base 7 and the movable mounting plate 9.

[0013] The fixed base 7 is formed with a mounting hole 29 that is open on the side of the fixed mold body 3, and the rear part of the partition member 30 is slidably provided in this mounting hole 29. Coil springs 31a, 31b are provided in this mounting hole 29 to bias the rear ends of the partition members 30a, 30b toward the fixed mold body 3. A flange 32 may be formed at the rear part of the partition member 30a and engaged with a step 33 formed in the mounting hole 29 to restrict the movement range of the partition member 30a. The partition members 30a, 30b are pressed against a female mold (fixed mold) 51 (described later) with their tips partitioning the runner groove 16 and the inside of the molding die 18 into at least two parts.

[0014] The fixed mold body 3 is composed of a fixed side mounting plate 50 which is attached to an injection device (not shown), a female mold mounting plate 52 to which a female mold 51 is attached, and spacers 53 provided on both sides between them. Reference numeral 55 denotes an injection nozzle connecting recess formed in the fixed side mounting plate 50. The tip of the injection nozzle attached to this connecting recess 55 is connected to a sprue hole 56 formed in the female mold mounting plate 52 and the female mold 51. This sprue hole 56 is formed so as to communicate with the runner grooves 15, 16.

[0015] <Partition member 30a> The partition member 30a will be described in detail with reference to Figures 1 and 2. The partition member 30a is provided on the movable mold body 2 (or the fixed mold body 3) so as to be able to enter and exit the runner groove 16 so as to separate the inside of the runner groove 16. The partition member 30a is biased in a direction in which it moves out into the runner groove 16 by an elastic member 31a.

[0016] 2, the partition member 30a that separates the runner groove 16 is formed in a round shaft shape in this embodiment, although the cross-sectional shape is not particularly limited. If it is a round shaft shape, it is easy to process a die that accommodates the partition member 30a, and the partition member 30a can be manufactured by processing a conventionally used ejector pin. The partition member 30a is not limited to a round shaft shape, and may be formed in a square column shape.

[0017] A small diameter portion 35 is formed at the tip of the partition member 30a, and the tip of this small diameter portion 35 is biased by a coil spring 31a, protrudes into the runner groove 16, and is pressed against the female die 51. One surface (the surface at the back in FIG. 2, the regulating surface) 36 of this small diameter portion 35 is approximately perpendicular to the direction in which the molding resin material flows through the runner groove 16, which will be described later. In addition, a step recess 40 is formed on the other surface (the surface at the front in FIG. 2) 37, which is open up to an upper end surface 39 of the partition member 30a.

[0018] There is no particular limitation on the shape of the step recess 40. For example, the step recess 40 shown in Fig. 2 includes a recess 40a forming a hemispherical depression formed in the center of the upper end surface having a circular cross section, and a notch 40b cut out from this hemispherical recess toward the other surface 37.

[0019] FIG. 3(A) shows a perspective view of the male mold 5 with the partition member 30a accommodated in the runner groove 16. A pair of squeeze pins 16a are arranged in the runner groove 16 to sandwich the partition member 30a. The squeeze pins 16a suppress the force of the flowing resin and prevent the resin from flowing over the partition member 30a to the opposite side. A protrusion 16b is arranged in the runner groove 16 adjacent to the partition member 30a, protruding into the runner groove 16 on one surface (regulating surface) 36 side of the partition member 30a, for forming a concave portion 17a having a wall portion 17a1 that covers a part of the partition member 30a in the runner R described later. FIG. 3(B) shows a state in which the partition member 30a accommodated in the runner groove 16 of the male mold 5 is in a retracted position. FIG. 3(C) shows an enlarged perspective view of the partition member 30a. 3(A), 3(B), and 3(C) show a state in which the runner groove 16 is not filled with resin.

[0020] <Runner R> The runner R in this embodiment will be described with reference to Figs. 4 and 5. Figs. 4(A) and 5(A) are perspective views of the runner R constituting a part of the resin molded product according to the first embodiment of the present invention. Fig. 4(B) is a cross-sectional view taken along line IV-IV in Fig. 4(A). Fig. 5(B) is a cross-sectional view taken along line VV in Fig. 5(A). As shown in Fig. 4(A), the runner R includes a first runner portion A1 formed of a first resin A, a second runner portion B1 formed of a second resin B, and a joint portion 17 where the first resin A and the second resin B join together. Thus, the runner R forms a part of the resin molded product molded from a plurality of resins. The first runner portion A1 and the second runner portion B1 are disposed on opposite sides of each other via the joint portion 17, and include openings A2 and B2 formed by the drawing pin 16a, respectively.

[0021] The joint portion 17 includes a first joint portion 17a molded from a first resin A and a second joint portion 17b molded from a second resin B. The second joint portion 17b is molded in the runner groove 16 by retracting the partition member 30a described below, and therefore includes a bottom portion to which the shape of the step recess 40 of the partition member 30a is transferred, and a cylindrical portion having the same diameter as the small diameter portion 35 of the partition member 30a.

[0022] On the other hand, the first joint part 17a is formed in a concave shape having a wall part 17a1 that contacts a part of the side surface of the cylindrical part of the second joint part 17b and a bottom part (deep part) 17a2. That is, the concave shape is composed of the bottom part 17a2 and the wall part 17a1 erected around the bottom part 17a2. However, the concave shape is not limited to the above, and for example, instead of the space defined by the bottom part 17a2 and the side wall 17a1, a hemispherical depression may be adopted like the recess 40a of the above-mentioned stepped recess 40. That is, the concave shape may not have a bottom part. By doing so, the shape of the protrusion part 16b described later can be made simple.

[0023] In this embodiment, the bottom 17a2 has a shape in which an arc, which is the cross-sectional shape of the second joint part 17b, is cut from one side of a rectangle. A part of the wall part 17a1 erected on the arc-shaped part of the bottom 17a2 is disposed so as to cover the side surface of the second joint part 17b. The inner peripheral surface of the wall part 17a1 is formed along a part of the second joint part 17b. In this way, the side surface of the second joint part 17b can be covered with a part of the thin wall part 17a1, and the bonding force between the first joint part 17a1 and the second joint part 17a2 can be effectively strengthened with a small volume of resin (see FIG. 4(B)).

[0024] On the other hand, for example, if the second joint part 17b is a prism having a rectangular cross section, the wall part 17a1 of the first joint part 17a may be a partially linear wall part 17a1 that contacts one side of the prism of the second joint part 17b. In other words, the wall part 17a1 is not limited to a curved shape, and may be linear.

[0025] The first joint portion 17a will be described in detail with reference to the cross-sectional view shown in FIG. 5B. When the diameter of the second runner portion B1 (the same applies to the first runner portion A1) having a circular cross section is R1, the thickness of the first joint portion 17a is t1. In this case, the thickness t1 is set smaller than the diameter R1. For example, when R1 is set to about 3.0 mm, the thickness t1 may be set to about 1.5 mm. In other words, the first joint portion 17a is formed thinner than the first runner portion A1 or the second runner portion B1.

[0026] 5B, at least a part of inner peripheral surface 17a1a of wall portion 17a1 in the left-right direction is an inclined surface that is inclined from bottom 17a2 of the concave shape toward the top of wall portion 17a1 at an inclination angle Θ1 toward the outside of the concave shape. At least a part of outer peripheral surface 17a1b of wall portion 17a1 is an inclined surface that is inclined at an inclination angle Θ2 toward the inside of the concave shape toward the top of wall portion 17a1. The inclination angles Θ1 and Θ2 can be, for example, about 5 degrees.

[0027] The wall portion 17a1 is configured such that the horizontal cross-sectional area gradually decreases from the bottom portion 17a2 toward the top of the wall portion 17a1. In other words, by making the inner and outer peripheral surfaces of the wall portion 17a1 inclined surfaces, the force acting on the first joint portion 17a can be reduced when the runner R is removed from the mold, and it is possible to prevent an unnecessary force from acting on the fastening portion between the first joint portion 17a and the second joint portion 17b. Therefore, it is possible to prevent the first joint portion 17a and the second joint portion 17b from being released from the connection and separated when the runner R is removed from the mold. In addition, since an unnecessary force is prevented from acting on the fastening portion between the first joint portion 17a and the second joint portion 17b when the runner R is removed from the mold, it is possible to prevent the connection between the first joint portion 17a and the second joint portion 17b from being already weakened at the time of completion of molding. Therefore, even when the resin molded product according to this embodiment is applied to plastic model parts and the runners that support them in a plastic model kit, it is possible to prevent the connection between first joint portion 17a and second joint portion 17b from being released due to vibration or impact while the plastic model kit is being transported in a product packaging box.

[0028] In this embodiment, the wall 17a1 and bottom 17a2 constituting the first joint portion 17a are each formed of a thin material, which further reduces the force acting on the first joint portion 17a when the runner R is removed from the mold, and also accelerates the hardening of the first joint portion 17a, which will be described later. For example, when the thickness t1 of the first joint portion 17a is about 1.5 mm, the thickness of the bottom portion 17a2 can be about 0.5 mm.

[0029] Furthermore, the first joint portion 17a is molded with a smaller volume than the volume of the first joint portion 17a of the adjacent first runner portion A1 at the same length. Specifically, referring to FIG. 5(A), the axial length of the first joint portion 17a is d1, and the axial length of the first joint portion 17a in the first runner portion A1 is d2. d1 and d2 are the same length. At this time, the volume of the first joint portion 17a at the length d1 is set smaller than the volume of the first runner portion A1 at the length d2. Note that, in the past, the portion corresponding to the first joint portion was molded as solid with a thickness of, for example, about 2.5 mm.

[0030] That is, as described above, the first joint portion 17a is set to be thinner than the first runner portion A1, and furthermore, has a concave shape composed of a thin wall portion 17a1 and a bottom portion 17a2, so that the volume is smaller than that of the first runner portion A1 of the same length. In this way, the volume of the first runner portion A1 adjacent to the first joint portion 17a is reduced and the contact area with the mold is increased, so that the first joint portion 17a can be hardened quickly during molding, which will be described later.

[0031] <Forming process> With reference to Figures 6(A) and 6(B), the molding process of the runner R in the first embodiment will be described. The cross-sectional views shown in Figures 6(A) and 6(B) are cross-sectional views of the mold cut along the line VI-VI in Figure 3(A), for example. First, when the male mold 5 and the female mold 51 are closed as shown in Figure 1, an injection device (not shown) is connected to the mold and injects the first resin A flowing from one side of the runner groove into the molding space 18 and the runner groove 16 from the recess 11 connecting the injection nozzle (first injection process). Next, without waiting for the completion of injection of the first resin A, the injection device injects the second resin B flowing from the other side of the runner groove 16 into the mold from the recess 12 connecting the injection nozzle, for example (second injection process).

[0032] In the first injection step, as shown in FIG. 6(A), the first resin A flows from the left side to the right side in the figure, and fills the space in the runner groove 16 on the side of one surface (regulating surface) 36 of the partition member 30a where the protrusion 16b is arranged. At this time, the regulating surface side of the partition member 30a regulates the flow of the first resin A flowing from one side (the left side in the figure) of the runner groove 16 (regulating step). In other words, the one surface 36 of the partition member 30a is approximately perpendicular to the inflow direction of the molding resin material, and can block the flow of the molding resin material flowing toward this one surface 36 side. The first resin A is then blocked by the one surface 36 of the partition member 30a, and the flow stops.

[0033] At this time, the first resin A molds a first joint portion (concave portion) 17a having a concave shape including a wall portion 17a1 and a bottom portion 17a2 surrounding a part of the partition member 30a in the runner groove 16 on one surface (regulating surface) 36 side (first molding step). Here, referring to Figs. 3(A) and 3(C), the protrusion portion 16b in the runner groove 16 has a first side surface 16b1 facing the surface 16d of the runner groove 16 and a second side surface 16b2 along a part of the partition member 30a at a predetermined distance from one surface of the partition member 30a. As shown in Fig. 3(C), the second side surface 16b2 is separated from one surface of the partition member 30a by a predetermined distance d. As described above, since the wall portion 17a1 of the first joint portion 17a has an inclined surface, at least the first side surface 16b1 of the protrusion portion 16b and the surface 16d of the runner groove 16 are formed as inclined surfaces.

[0034] As described above, the concave first joint portion 17a is formed by the thin wall portion 17a1 and bottom portion 17a2, and its volume is set small, so that it hardens quickly. In other words, the first joint portion 17a is provided with the thin bottom portion 17a2 and the thin wall portion 17a1 surrounding it by the protrusion portion 16b of the runner groove 16, so that the contact area with the mold is large and it hardens quickly.

[0035] For example, in the runner groove 16 where the protrusion 16b is not formed, a solid runner without a concave shape is formed at the location corresponding to the first joint part. In this case, a certain time is required for the inside of the solid runner to cool, and therefore a certain time is required for hardening, compared to the concave first joint part 17a of the present embodiment. Therefore, the concave first joint part 17a molded from the first resin A is hardened quickly (hardening process) compared to the conventional method.

[0036] Next, as shown in FIG. 6B, a second resin B of, for example, a different color is injected into the runner groove 16 by an injection nozzle connected to the connecting recess 55. When the second resin B flows from the other side of the runner groove 16 (from the right side to the left side in the figure), the second resin B is temporarily blocked by the other surface 37 of the small diameter portion 35 of the partition member 30a, but flows into the step recess 40. The flow pressure of this second resin B presses the hemispherical recess 41a of the step recess 40 in the direction of the arrow A, and the partition member 30a is pressed down against the biasing force of the elastic member 31a. The state at this time is shown in FIG. 3B. Therefore, the partition member 30a is retreated from the runner groove 16 by the flow of the second resin B flowing from the other side of the runner groove 16 (retraction process). In this way, the second resin B forms a joint portion that joins with the concave portion formed in the first molding process (second formation process).

[0037] In other words, when the second resin B reaches the partition member 30a, the hardening of the first joint portion 17a is completed, so after the first injecting unit injects the first resin A, the second injecting unit can inject the second resin B without waiting for the completion of injection of the first resin A. Therefore, it is possible to provide a resin molded product with a reduced molding time.

[0038] The timing at which the second resin B reaches the partition member 30a is changed as appropriate depending on the position from the gate of the mold to the partition member 30a and the protrusion 16b of the present invention, but at least the hardening of the portion corresponding to the first joint portion 17a is accelerated compared to the conventional method, thereby shortening the injection molding cycle and improving the freedom of mold design. The molding cycle is shortened by, for example, 3 seconds when the present invention is applied and the conventional method are compared with the same mold design.

[0039] In the runner R thus molded, the cylindrical second joint portion 17b corresponding to the shape of the partition member 30a is fitted into the curved surface formed by a part of the wall portion 17a1 of the first joint portion 17a, as shown in Fig. 4. That is, the first joint portion 17a forms a molded recess that surrounds half of the small diameter portion of the second joint portion 17b, and this molded recess embraces the second joint portion 17b, so that the welding between the first joint portion 17a made of the first resin A and the second joint portion 17b made of the second resin B is strong. Therefore, even if the resin molded product according to this embodiment is applied to the parts of a plastic model in a plastic model kit and the runner that supports the parts, it is possible to prevent the welding between the first joint portion 17a and the second joint portion 17b from being released due to vibration or impact during transportation of the plastic model kit in a product packaging box.

[0040] 1 is then separated from the fixed mold body 3, and the pressing shaft 25 is pressed to move the push-out plate 20, causing the knock-out pins 21... on the push-out plate 20 to push out the multi-color runner R and the multi-color molded product adhering to the male die 5 of the movable mold body 2, allowing them to be removed. In the above embodiment, the partition member 30 and the protrusion 16b are provided on the movable mold body 2 side, but they may be provided on the fixed mold body 3 side. Also, although the coil spring 31 is used as the elastic member for biasing the partition member 30, other elastic parts such as rubber and a leaf spring may be used.

[0041] Second Embodiment 7 and 8 show an example in which a pair of partition members 100 are arranged in the runner groove 85 to sandwich a protrusion 127, and the regulating surface 106 of each partition member 100 is arranged opposite the protrusion 127. The second embodiment differs from the first embodiment in that a pair of partition members 100 is provided, and other configurations are the same as those of the first embodiment.

[0042] The partition member 100 is formed in the shape of a round shaft, similar to the partition member 30a shown in Fig. 2, with a stepped recess 110 formed at its tip and a flange 102 provided at its lower end. The rear part of this partition member 100 is slidably provided in a shaft hole 99 formed in the front push plate 90. The flange 102 of the partition member 100 is slidably attached to the slide hole 96 of the front push plate 90, and is biased in the direction of the runner groove 85 by a spring 101 provided in a spring receiving hole 104 of the rear push plate 91, so as to engage with an upper wall 103 of the slide hole 96.

[0043] Furthermore, the flange 102 is pushed down against the elasticity of the spring 101 until it abuts against a step 117 formed in the upper part of the spring receiving hole 104. Furthermore, an engagement groove 116 is formed on one side of the sliding hole 96, and an engagement shaft 115 provided on the flange 102 is slidably engaged with this engagement groove 116. Therefore, the partition member 100 does not rotate.

[0044] The tip of the partition member 100 is biased by the elasticity of the coil spring 101, protruding into the runner groove 85 and pressing against the female die 122. One surface 106 of this partition member 100 is approximately perpendicular to the direction in which the molding resin material flows through the runner groove 85. The other surface 107 is formed with a stepped recess 110 that opens up to the upper end surface 109 of the partition member 100. The partition members 100 are provided in pairs and protrude into each runner groove 85. The two partition members 100, 100 are provided so that one surface 106, 106 faces each other.

[0045] As shown in FIG. 8(A), the injection device causes the first resin A to flow from one side (the left side in the figure) of the runner groove 85. This first resin A flows into a step recess 110 formed in the other surface 107 of the partition member 100 on the left side in the figure. The flow pressure of this first resin A presses the bottom surface 111 of the step recess 110, and the partition member 100 on the left side in the figure is pressed down against the biasing force of the elastic member 101. The first resin A flows as it is in the runner groove 85 and is blocked by one surface 106 of the next partition member 100, stopping the flow. At this time, a concave first joint portion 217a is formed.

[0046] 8(B), when a second resin B of a different color is injected from the other side (the right side in the figure) of the runner groove 85 by the injection device, this second resin B flows into a step recess 110 formed in the other surface 107 of the partition member 100 on the right side in the figure. The flow pressure of this second resin B presses the bottom surface 111 of the step recess 110, and the partition member 100 on the right side in the figure is pressed down against the biasing force of the elastic member 101. The second resin B of a different color flows into the position where the partition member 100 on the right side in the figure was located, and is welded to the initial first resin A. In this way, a multi-colored runner 84 is formed in the runner groove 85.

[0047] The runner 84 formed as described above is shown in Figures 10 and 11. The runner 84 shown in Figures 10 and 11 has a reference number beginning with 2 to indicate that it is the same member as the runner R shown in Figures 5 and 6. The runner 84 has the same shape as the runner R, except that the first joint portion 217a is formed with a portion 200 shaped to correspond to the partition member 100.

[0048] In the second embodiment described above, for example, because partition members 100 are disposed on both sides of protrusion 127 of runner groove 85, it is possible to, for example, inject simultaneously without adjusting the injection time of each injection nozzle. In this way, by providing a pair of opposing partition members 30 in one runner groove, if either the first resin A or the second resin B reaches protrusion 127 first, the hardening of that resin is accelerated, so that it is possible to inject simultaneously without adjusting the injection time of each injection nozzle, and it is possible to further improve molding efficiency.

[0049] As described above, in this embodiment, there is no need to wait for the joint parts to harden as in conventional molding devices, and the injection time required to mold a multi-color runner or a multi-color molded product can be shortened with a very simple mechanism that only requires providing a protrusion with one mold. In addition, since the mechanism is simple and can be made small and lightweight, it can be manufactured at low cost, and even if it is attached to an injection device, the burden on the injection device is small. Furthermore, since it is not necessary to inject and mold each color of molding resin material in order, and it is possible to injection mold them simultaneously, the molding cycle of the molded product can be extremely shortened, which improves production efficiency and reduces production costs.

[0050] In addition, since the amount of the first resin A in the joint portion near one surface of the partition member is reduced, the first resin A near one surface of the partition member hardens faster than in conventional molding devices. This allows the second resin B to be injected faster than in conventional molding devices, improving molding efficiency and increasing the freedom of mold design. The present invention is applicable to resin molded products that are distributed without separating the molded product from the runner, such as plastic model kits. [Explanation of symbols]

[0051] 17a first joint portion, 17a1 wall portion, 17b second joint portion, A first resin, B second resin, 84, R runner

Claims

1. A resin molded product is molded from a plurality of resins and has a joint portion where a first resin and a second resin join in a runner, the joint portion includes a first joint portion molded from the first resin and a second joint portion molded from the second resin, the first joint portion is formed to have a wall portion in contact with a portion of the second joint portion; The resin molded product, wherein the wall portion is thinner than the runner, and the first joint portion is thinner than the runner.

2. The resin molded product according to claim 1 , wherein the wall portion covers the part of the second joint portion.

3. 3. The resin molded product according to claim 1, wherein at least a part of an inner peripheral surface of the wall portion is an inclined surface that inclines outwardly from the wall portion toward an end portion of the wall portion.

4. 4. The resin molded product according to claim 1, wherein an inner circumferential surface of the wall portion is formed along a part of the second joint portion.

5. 5. The resin molded product according to claim 1, wherein at least a part of an outer circumferential surface of the wall portion is an inclined surface that slopes inwardly toward the end of the wall portion.

6. 6. The resin molded product according to claim 1, wherein the first joint portion is molded to have a smaller volume than a volume of the first joint portion of an adjacent runner over the same length.

7. an injection device that injects a molding material; A plurality of dies that, when fitted together, form a molding space for molding a molded product and a runner groove connected to the molding space; a partition member provided in at least one of the molds, capable of entering and exiting the runner groove, and partitioning the runner groove; A molding apparatus comprising: the injection device is connected to the mold and injects the molding material into the molding space and the runner groove; the partition member includes a regulating surface that regulates the flow of the molding material flowing from one side of the runner groove, and a step recess that allows the partition member to move away from the runner groove by the flow of the molding material flowing from the other side of the runner groove, the die includes a protrusion that protrudes into the runner groove on the regulating surface side and forms a wall portion on the runner that comes into contact with a part of the partition member, The protrusion has a side surface, and the wall is formed by the side surface. The molding apparatus is characterized in that the width and thickness of the wall portion are formed thinner than those of the runner.

8. The molding apparatus according to claim 7, characterized in that the protrusion portion has an inclined surface for molding at least a portion of an inner circumferential surface of the wall portion of the runner so as to incline outwardly from the wall portion toward an end of the wall portion.

9. 9. The molding apparatus according to claim 7, wherein the protrusion has a side surface along a part of the partition member, the side surface being spaced a predetermined distance from the partition member.

10. The molding apparatus according to any one of claims 7 to 9, characterized in that the runner groove has an inclined surface for forming at least a portion of the outer peripheral surface of the wall portion of the runner so as to incline inwardly toward the end of the wall portion.

11. The injection device includes at least a first injection section that injects a first resin that flows from the one of the runner grooves; a second injection section that injects a second resin flowing from the other of the runner grooves; Equipped with The molding apparatus according to any one of claims 7 to 10, characterized in that after the first injection section has injected the first resin, the second injection section injects the second resin without waiting for completion of injection of the first resin.

12. The mold is A moving side mold attached to a moving side of the molding device; A fixed side mold attached to a fixed side of the molding device; Equipped with The molding apparatus according to claim 7 , wherein the partition member and the protrusion are disposed on the movable mold.

13. A molding apparatus described in any one of claims 7 to 12, characterized in that the partition member is biased by an elastic member in a direction protruding into the runner groove, and is retreated from the runner groove against the biasing force of the elastic member by the molding material flowing into the step recess.

14. The partition members are arranged in a pair in the runner groove so as to sandwich the protrusion therebetween, The molding apparatus according to claim 7 , wherein the regulating surface of each partition member is disposed opposite the protrusion.

15. an injection device that injects molding resin; A plurality of dies that, when fitted together, form a molding space for molding a molded product and a runner groove connected to the molding space; a partition member provided in at least one of the molds, capable of entering and exiting the runner groove, and partitioning the runner groove; A molding method for a molding apparatus comprising: a first injection step in which the injection device is connected to the mold and injects a first resin flowing from one side of the runner groove into the molding space and the runner groove; a second injection step in which the injection device injects a second resin flowing from the other of the runner grooves into the mold without waiting for the completion of injection of the first resin; a restricting step of restricting a flow of the first resin flowing from the one side of the runner groove by the partition member; a first molding process in which the first resin is molded into the runner groove on a regulating surface side to form a wall portion surrounding a part of the partition member; a hardening step of hardening the wall portion molded from the first resin; a retracting step in which the partition member is retracted from the runner groove by a flow of the second resin flowing from the other side of the runner groove; a second molding step in which the second resin is molded into a joint portion that is joined to the wall portion molded in the first molding step; Equipped with A molding method for a molding apparatus, characterized in that the width and thickness of the wall portion are formed thinner than the runner formed by the runner groove.

16. A mold forming a molding space for molding a molded product and a runner groove connected to the molding space, a partition member that divides the runner groove and is capable of entering and exiting the runner groove and that includes a regulating surface that regulates the flow of molding material flowing from one side of the runner groove and a step recess that allows the partition member to retreat from the runner groove by the flow of the molding material flowing from the other side of the runner groove; a protrusion portion that protrudes into the runner groove on the regulating surface side and forms a wall portion on the runner to cover a part of the partition member; Equipped with The mold is characterized in that the width and thickness of the wall portion are formed thinner than those of the runner.

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