JP2018202704A - Method for producing resin molded article - Google Patents

Abstract

To form a desired texture reliably on an inner surface of a hollow resin molded article.SOLUTION: A method for producing a resin molded article (drain pipe 10) having a hollow portion (flow path 11) includes joining a first divided body 21 and a second divided body 22 to each other. The method includes a molding step of primarily injecting a resin material into a space (cavity 210, 220) formed by a first mold 400 and a second mold 500 to mold the first divided body and the second divided body, a moving step of approaching the first divided body and the second divided body close to each other by relative displacement of the first mold and the second mold, and a bonding step of bonding the first divided body and the second divided body to each other. A texture molding portion of an inner surface of the hollow portion is provided in at least one of a region corresponding to the second divided body in the molding step in the first mold and a region corresponding to the first divided body in the molding step in the second mold.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method for producing a hollow resin molded product such as a drain pipe.

  For example, what is formed by blow molding as a hollow resin molded product such as a drain pipe is known (for example, see Patent Document 1).

JP 2007-138498 A

  By the way, in a drain pipe, in order to control the flow of drainage, it is examined to form a desired texture (texture, roughness, unevenness, etc.) on the inner surface of a flow path. However, when the drain pipe is formed by blow molding, the formation of a desired texture on the inner surface of the flow path requires execution of a process dedicated to texture formation after blow molding, and the entire manufacturing process becomes long. In addition, depending on the shape of the drain pipe, it may be difficult to form a desired texture on the inner surface of the flow path after blow molding.

  Then, this invention aims at providing the manufacturing method of the resin molded product which can form a desired texture reliably in the inner surface of a hollow resin molded product, without performing the process only for texture formation. .

  In order to achieve the above object, a method for producing a resin molded product according to one aspect of the present invention is a resin molding for molding a resin molded product having a hollow portion by joining a first divided body and a second divided body. A method of manufacturing a product, wherein a resin material is first injected into a space formed by a first mold and a second mold, and a first divided body and a second divided body are individually molded; and While the first divided body is held by the first mold and the second divided body is held by the second mold, the first divided body and the second divided body are moved by relative movement of the first mold and the second mold. Including a moving step of bringing the respective joining edges of the divided body closer to each other, and a joining step of joining the respective joined edges of the first divided body and the second divided body, in the molding step in the first mold A region corresponding to the second divided body and a region corresponding to the first divided body in the molding process in the second mold. At least one of A, texture forming unit for forming the texture of the inner surface of the resin molded article is provided.

  According to the method for manufacturing a resin molded product according to one aspect of the present invention, a desired texture can be reliably formed on the inner surface of a hollow resin molded product without performing a process dedicated to texture formation.

FIG. 1 is a front view showing a schematic configuration of a drain pipe according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the same drain pipe. FIG. 3 is an enlarged cross-sectional view showing the inner surface shapes of the first divided body and the second divided body of the drainage pipe. FIG. 4 is a cross-sectional view showing the mold according to the first embodiment and in a state where the mold is opened. FIG. 5 is a cross-sectional view showing the same mold as in the first embodiment, but closed in the primary injection. FIG. 6 is an enlarged cross-sectional view showing a region forming the internal shape of the first divided body in the first core portion according to the first embodiment. FIG. 7 is a cross-sectional view showing the state of the mold during the molding process according to the first embodiment. FIG. 8 is a cross-sectional view showing a state of the mold during the moving process according to the first embodiment. FIG. 9 is a cross-sectional view showing the state of the mold during the joining step according to the first embodiment. FIG. 10 is a cross-sectional view of a drain pipe according to the second embodiment. FIG. 11 is an enlarged cross-sectional view showing a part of the drain pipe before the secondary injection according to the second embodiment. FIG. 12 is an enlarged cross-sectional view showing a part of the drain pipe before the secondary injection according to the second embodiment. FIG. 13 is a cross-sectional view of the first divided body and the second divided body during the moving process according to the third embodiment. FIG. 14 is a cross-sectional view of the first divided body and the second divided body after the moving process according to the third embodiment and before the secondary injection. FIG. 15 is an enlarged sectional view showing a part of the first divided body and the second divided body before the secondary injection after the moving process according to the third embodiment. FIG. 16 is an enlarged cross-sectional view showing a part of the first divided body, the second divided body, and the resin material after the secondary injection in the joining step according to the third embodiment. FIG. 17 is an enlarged cross-sectional view showing a part of the first divided body, the second divided body, and the resin material after the secondary injection in the joining process according to the comparative example.

  Below, the manufacturing method of the resin molded product which concerns on embodiment of this invention is demonstrated in detail using drawing. Each of the embodiments described below shows a preferred specific example of the present invention. Accordingly, numerical values, shapes, materials, components, arrangement and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member.

(First embodiment)
Hereinafter, the manufacturing method of the resin molded product which concerns on 1st embodiment is demonstrated based on FIGS.

[Resin molded product]
First, an example of a resin molded product molded by the method for manufacturing a resin molded product according to the first embodiment will be described. Here, a resin drain pipe will be described as an example of the resin molded product. In addition, as a resin molded product, it is not limited to a drain pipe, What is necessary is just a resin molded product which has a hollow part.

  FIG. 1 is a front view showing a schematic configuration of a drain pipe according to the first embodiment. FIG. 2 is a cross-sectional view of the drain pipe according to the first embodiment. Specifically, FIG. 2 is a cross-sectional view as seen from the section taken along the line II-II in FIG.

  As shown in FIG.1 and FIG.2, the drain pipe 10 is an S-shaped trap which has the S-shaped flow path 11 as a hollow part, for example. Here, an S-shaped trap is illustrated as an example of the drain pipe 10, but for example, a P-shaped drain pipe other than the S-shaped trap may be used.

  The drain pipe 10 has an inflow port 12 formed in the upper portion and an outflow port 13 formed in the lower portion, and an S-shaped flow path 11 is formed so as to connect the inflow port 12 and the outflow port 13. . Although the drain pipe 10 is integrally formed of a resin material, it is divided into a first divided body 21 and a second divided body 22 at the time of manufacture, and the first divided body 21, By joining the second divided body 22 with the joint portion 23, the entire drain pipe 10 is integrated.

  The first divided body 21 is a portion forming the upper half of the drain pipe 10 in FIG. The first divided body 21 is formed with a first groove 211 having an S-shape in front view that forms the flow path 11. A concave portion 213 is formed in the joining edge 212 of the first divided body 21 with the second divided body 22. The recess 213 is formed along the outer surface of the first divided body 21, and the joint 23 is provided in the recess 213.

  The second divided body 22 is a portion forming the lower half of the drain pipe 10 in FIG. The second divided body 22 is formed with a second groove portion 221 having an S-shape in front view that forms the flow path 11. A concave portion 223 is formed in the joining edge 222 of the second divided body 22 with the first divided body 21. The concave portion 223 is formed along the outer surface of the second divided body 22, and the joint portion 23 is provided in the concave portion 223.

  By joining the first divided body 21 and the second divided body 22, the first groove 211 and the second groove 221 constitute the flow path 11. The channel 11 includes a first straight part 111, a second straight part 112, a third straight part 113, a first bent part 114, and a second bent part 115. The 1st straight line part 111, the 2nd straight line part 112, and the 3rd straight line part 113 are arranged in parallel. The first bent portion 114 and the second bent portion 115 are bent in a U shape.

  Hereinafter, the upstream side will be described as the base end portion and the downstream side will be described as the front end portion with reference to the flow of the drainage passing through the drain pipe 10. The base end portion of the first straight portion 111 is continuous with the inflow port 12. The distal end portion of the first straight portion 111 and the proximal end portion of the first bent portion 114 are continuous. The distal end portion of the first bending portion 114 and the proximal end portion of the second linear portion 112 are continuous. The distal end portion of the second straight portion 112 and the proximal end portion of the second bent portion 115 are continuous. The distal end portion of the second bending portion 115 and the proximal end portion of the third linear portion 113 are continuous. The tip of the third straight line 113 is continuous with the outlet 13.

  In the first divided body 21 and the second divided body 22, first gaps 24 and 25 are formed between the outer walls of the first straight portion 111 and the second straight portion 112 facing each other by the first bent portion 114. Has been. Further, in the first divided body 21 and the second divided body 22, second gaps 26 and 27 are formed between the outer walls of the second straight portion 112 and the third straight portion 113 that are opposed by the second bending portion 115. Has been. Joint portions 23 are provided in the first gaps 24 and 25 and the second gaps 26 and 27, respectively.

  The joint portion 23 is a portion that fills the recesses 213 and 223 and joins the first divided body 21 and the second divided body 22 together. In the joint portion 23, portions corresponding to the first gaps 24 and 25 and the second gaps 26 and 27 are ribs 231 protruding from one outer wall of the opposed outer walls toward the other outer wall. Specifically, the rib 231 is connected to the outer walls of the first divided body 21 and the second divided body 22. In addition, the rib 231 may be spaced apart from one outer wall of the opposing outer walls or the other outer wall. In FIG. 1, the rib 231 is illustrated as being continuously formed along the longitudinal direction of each of the first gaps 24 and 25 and the second gaps 26 and 27. It may be formed automatically.

  FIG. 3 is an enlarged sectional view showing the inner surface shapes of the first divided body 21 and the second divided body 22 according to the first embodiment. Specifically, FIG. 3 shows an enlarged view of the one-dot chain lines C1 and C2 in FIG.

  As shown in FIG. 3, the inner surface shape of the first divided body 21 and the second divided body 22, that is, the inner surface shape forming the flow path 11 is formed by intermittently patterning a concave portion 19 having a rectangular shape in cross section. ing. Thereby, the unevenness | corrugation is continuously formed in the flow-path inner surface of the drain pipe 10. As shown in FIG. This unevenness constitutes the texture 18 on the inner surface of the flow path. Note that the texture 18 shown in FIG. 3 is merely an example of a texture, and the shape and size of the texture may be anything. Further, the texture may be provided on the entire inner surface of the flow path or may be provided partially. What is necessary is just to employ | adopt the texture suitable in order to control the waste_water | drain which flows through the flow path 11. FIG.

[Mold]
Next, a mold for forming the drain pipe 10 will be described.

  FIG. 4 is a cross-sectional view showing the mold according to the first embodiment and in a state where the mold is opened. FIG. 5 is a cross-sectional view showing a mold according to the first embodiment, which is closed at the time of primary injection.

  As shown in FIGS. 4 and 5, the mold 300 is provided in a molding machine (not shown) that performs die slide injection molding (DSI molding), and includes a first mold 400 and a second mold 500. I have. The first mold 400 and the second mold 500 are made of a metal material such as stainless steel, for example.

  The first mold 400 is a mold for molding a part of the first divided body 21 and a part of the second divided body 22. Specifically, the first mold 400 has a first cavity portion 410 for molding the external shape of the first divided body 21, and an internal shape of the second divided body 22 and a first cavity for molding the recess 223. 1 core part 420 is provided. In the first cavity portion 410, a recess corresponding to the external shape of the first divided body 21 is formed. The first core portion 420 is formed with convex portions corresponding to the internal shape of the second divided body 22 and the concave portions 223.

  The second mold 500 is a mold for molding a part of the first divided body 21 and a part of the second divided body 22. Specifically, the second mold 500 has a second core portion 510 for molding the internal shape of the first divided body 21 and the concave portion 213, and a second shape for molding the external shape of the second divided body 22. A two-cavity portion 520 is provided. In the second cavity portion 520, a recess corresponding to the external shape of the second divided body 22 is formed. The second core portion 510 is formed with a convex portion corresponding to the internal shape of the first divided body 21 and the concave portion 213.

  FIG. 6 is an enlarged cross-sectional view showing a region forming the internal shape of the second divided body 22 in the first core part 420 according to the first embodiment. In addition, in FIG. 6, the 2nd division body 22 shape | molded by the 1st core part 420 is also shown in figure.

  As shown in FIG. 6, a texture forming portion 425 for forming the texture of the inner surface of the flow path is formed in a region where the internal shape of the second divided body 22 is formed in the first core portion 420. The texture forming unit 425 has an uneven shape corresponding to the texture 18. That is, by forming the shape corresponding to the desired texture 18 in the texture forming portion 425, the desired texture 18 can be formed on the inner surface of the flow path of the drain pipe 10 only by injection molding.

  A similar texture forming portion 425 is also provided in a region of the first core portion 420 that forms the internal shape of the second divided body 22.

  As shown in FIG. 5, when the first mold 400 and the second mold 500 are closed before the primary injection, the first cavity part 410 and the second core part 510 are used for the first divided body 21. The cavity (space) 210 of the second divided body 22 is formed by the second cavity portion 520 and the first core portion 420.

  The first mold 400 is formed with a first molding gate 450 for injecting a resin material for primary injection into the cavity 220. The injection port of the first molding gate 450 is arranged at a position corresponding to the concave portion 223 of the second divided body 22 in the first core portion 420.

  The second mold 500 is provided with a second molding gate 550 for injecting a resin material for primary injection into the cavity 210. The injection port of the second molding gate 550 is arranged at a position corresponding to the concave portion 213 of the first divided body 21 in the second core portion 510.

  Thus, the first molding gate 450 and the second molding gate 550 are primary injection gates, and the injection ports thereof are arranged at positions corresponding to the joint portions 23 formed by the recesses 213 and 223. ing.

  The second mold 500 is formed with a junction gate 560 for injecting a resin material for secondary injection. The junction gate 560 is a gate for secondary injection. The injection port of the junction gate 560 is disposed at a position corresponding to the rib 231 in the junction portion 23. Specifically, a plurality of junction gates 560 are provided so as to correspond to the ribs 231 formed in the gaps 25 and 27 of the second divided body 22 (two are shown in FIG. 4 and the like).

  The molding machine includes an injection molding unit (not shown) for injecting a resin material to the first molding gate 450, the second molding gate 550, and the joining gate 560, and the first mold 400 and the second mold. A first drive source (not shown) for switching between mold closing and mold opening of the mold 500 and a second drive source (not shown) for sliding the second mold 500 relative to the first mold 400 when the mold is opened. And are provided. Note that the slide movement of the second mold 500 by the second drive source may be linear movement or rotational movement, but in the following description, linear movement will be described as an example.

  Further, the molding machine includes a computer (control circuit) for controlling the operation of each device such as an injection molding unit, a first drive source, and a second drive source. The computer includes, for example, a nonvolatile memory in which a program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, and a processor that executes the program.

[Operation]
Then, the manufacturing method of the resin molded product which concerns on 1st embodiment is demonstrated. In the description of this manufacturing method, the resin material before curing is shown by shading.

  The method of manufacturing a resin molded product is performed by a computer of a molding machine executing a program to control operations of each device such as an injection molding unit, a first drive source, and a second drive source.

  First, at the time of standby, as shown in FIG. 4, the first mold 400 and the second mold 500 are in a state of being opened. Then, as the resin molding starts, the first mold 400 and the second mold 500 are closed as shown in FIG.

  After the mold is closed, a molding process is executed.

  FIG. 7 is a cross-sectional view showing a state of the mold 300 during the molding process according to the first embodiment. In FIG. 7, the resin material before curing is shown by shading.

  As shown in FIG. 7, the resin material is primarily injected into the cavities 210 and 220 from the first molding gate 450 and the second molding gate 550. Thereby, the 1st division body 21 and the 2nd division body 22 are shape | molded separately. At this time, a region (first core portion 420) corresponding to the second divided body 22 in the first mold 400, and a region (second core portion 510) corresponding to the first divided body 21 in the second mold 500. In addition, since the texture forming portion 425 is formed, the texture 18 is formed on the inner surface of the flow path between the first divided body 21 and the second divided body 22 (see FIG. 6).

  After the molding process, a moving process is performed.

  FIG. 8 is a cross-sectional view showing a state of the mold 300 during the moving process according to the first embodiment.

  After the molding process, when the first divided body 21 and the second divided body 22 are cured, the first mold 400 and the second mold 500 are once opened, and then the second mold 500 is the first mold. Slide and move with respect to the mold 400. Then, as shown in FIG. 8, the first mold 400 and the second mold 500 are closed again. The first divided body 21 is held in the first cavity part 410 of the first mold 400 and the second cavity part 520 of the second mold 500 has the first cavity between the opening of the mold and the closing of the mold again. A two-part body 22 is held. Then, by closing the mold, the joining edge 212 of the first divided body 21 and the joining edge 222 of the second divided body 22 approach each other and come into contact with each other.

  At this time, a space S <b> 1 filled with a secondary injection resin material is formed between the first mold 400, the second mold 500, the first divided body 21, and the second divided body 22.

  After the moving process, a joining process is performed.

  FIG. 9 is a cross-sectional view showing a state of the mold 300 during the joining process according to the first embodiment.

  As shown in FIG. 9, in the bonding process, the resin material is secondarily injected from the bonding gate 560 into the space S1. When the entire space S1 is filled with the resin material, the joint portion 23 is formed. By the joint portion 23, the joining edges 212 and 222 of the first divided body 21 and the second divided body 22 are joined to each other. The same resin material is used for the primary injection and the secondary injection. Examples of the resin material used in the primary injection and the secondary injection include thermoplastic materials such as PP (polypropylene) and ABS resin.

  Then, after the joining step, when the joining portion 23 is cured, the first mold 400 and the second mold 500 are opened, and the drain pipe 10 as shown in FIGS. 1 and 2 is taken out.

  In addition, before the resin material is secondarily injected into the space S1, surface modification such as plasma treatment is performed on the surface of the portion of the first divided body 21 and the second divided body 22 where the joint portion 23 is to be formed. A quality treatment may be applied. Thereby, minute irregularities are formed on the surface. The unevenness exerts an anchor effect, and the bonding strength between the second injected resin material and the first divided body 21 and the second divided body 22 can be improved.

(Second embodiment)
Next, the drain pipe which concerns on 2nd embodiment is demonstrated based on FIGS.

  FIG. 10 is a cross-sectional view of a drain pipe according to the second embodiment. Specifically, FIG. 10 corresponds to FIG. In addition, in the following description, in the part equivalent to the drain pipe 10 which concerns on 1st embodiment, the same code | symbol may be attached | subjected and the description may be abbreviate | omitted.

  As shown in FIG. 10, in the first divided body 21A and the second divided body 22A forming the drain pipe 10A, the outer walls forming the flow path 11 (see FIG. 1) are formed without a gap. 21 A of 1st division bodies are provided with the wall part 291 which divides | segments the 1st linear part 111 and the 2nd linear part 112, and the wall part 292 which divides the 2nd linear part 112 and the 3rd linear part 113. ing. Similarly, the second divided body 22A includes a wall portion 293 that divides the first straight portion 111 and the second straight portion 112, and a wall portion 294 that divides the second straight portion 112 and the third straight portion 113. Is provided.

  In the cross-sectional view, the wall portions 291 and 292 of the first divided body 21A are formed lower than the wall portions 293 and 294 of the second divided body 22A. The wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A are joined, and the wall portion 292 of the first divided body 21A and the wall portion 294 of the second divided body 22A are joined. Yes. Thereby, the joining position P of the wall portions 291, 292, 293, and 294 is a position biased outward of the first divided body 21 </ b> A.

  Further, the first divided body 21A and the second divided body 22A are formed with projections 281 and 282 projecting outward on the outer peripheral edge excluding the inflow port 12 and the outflow port 13. By joining the joining protrusions 281 and 282, the outer peripheral edges of the first divided body 21A and the second divided body 22A are integrated.

  At the time of molding the first divided body 21A, it is preferable that a gate for primary injection is provided at a location corresponding to at least one of the front end surfaces of the wall portions 291 and 292 of the first divided body 21A. On the other hand, at the time of molding the second divided body 22A, a gate for primary injection may be provided at a location corresponding to at least one of the front end surfaces of the wall portions 293 and 294 of the second divided body 22A. An arrow G1 in FIG. 10 illustrates the primary injection gate position of the first divided body 21A, and an arrow G2 illustrates the primary injection gate position of the second divided body 22A. What is necessary is just to manufacture a metal mold | die so that each gate may be arrange | positioned in such a position.

  FIG. 11 is an enlarged cross-sectional view showing a part of the drain pipe 10A before the secondary injection according to the second embodiment. Specifically, FIG. 11 shows a contact state between the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A, which is surrounded by the alternate long and short dash line L1 in FIG. Since the wall portion 292 of the first divided body 21A and the wall portion 294 of the second divided body 22A have the same structure, the description thereof is omitted.

  As shown in FIG. 11, the boundary between the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A is filled with a circular space in cross section over the entire length of the wall portions 291 and 293. A portion 298 is formed. In the first divided body 21A, at least one gate portion 299 that penetrates to the filling portion 298 is formed. By filling the filling portion 298 with the resin material for secondary injection through the gate portion 299, the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A are joined. . Here, as described above, since the joining position P of the wall portions 291 and 293 is a position biased outward of the first divided body 21A, the total length of the gate portion 299 can be shortened. Therefore, even if it passes through the gate part 299, the filling part 298 can be filled in a highly fluid state without cooling the resin material.

  FIG. 12 is an enlarged cross-sectional view showing a part of the drain pipe 10A before the secondary injection according to the second embodiment. Specifically, FIG. 12 shows an enlarged view of a portion surrounded by a one-dot chain line L2 in FIG.

  As shown in FIG. 12, the boundary between the joint protrusion 281 of the first divided body 21A and the joint protrusion 282 of the second divided body 22A is a space having a circular cross section over the entire length of the joint protrusions 281 and 282. A filling portion 288 is formed. In addition, at least one gate portion 289 that penetrates to the filling portion 288 is formed at the boundary between the bonding protrusion 281 and the bonding protrusion 282. The filling projections 281 and 282 are joined to each other by filling the filling portion 288 with the resin material for secondary injection via the gate portion 289.

  Further, a fitting portion 285 is formed at the boundary between the joining protrusion 281 and the joining protrusion 282 on the flow channel 11 side with respect to the filling portion 288. The fitting portion 285 includes a convex portion 285a formed on one of the first divided body 21A and the second divided body 22A and a concave portion 285b formed on the other. Although FIG. 12 illustrates the case where the convex portion 285a is formed in the second divided body 22A and the concave portion 285b is formed in the first divided body 21A, these may be reversed. The fitting part 285 is continuously formed along the entire length of the filling part 288. Even if the resin material tries to enter the flow path 11 side from the filling portion 288, the fitting portion 285 blocks it.

(Third embodiment)
Next, the drain pipe which concerns on 3rd embodiment is demonstrated based on FIGS.

  FIG. 13 is a cross-sectional view of a state where the first divided body and the second divided body of the drain pipe according to the third embodiment are divided, and FIG. 14 is after the movement process of the drain pipe according to the third embodiment. And it is sectional drawing before a joining process. Specifically, FIG. 14 is a diagram corresponding to FIG. 10 in the second embodiment. In addition, in the following description, in the part equivalent to 10 A of drainage pipes concerning 2nd embodiment, the same code | symbol may be attached | subjected and the description may be abbreviate | omitted.

  As shown in FIG. 13, in the first divided body 21B and the second divided body 22B forming the drain pipe 10B, the outer walls forming the flow path 11 (see FIG. 1) are formed without a gap. The second divided body 22B is provided with a wall portion that is provided between the first straight portion 111 and the second straight portion 112, and between the second straight portion 112 and the third straight portion 113, and divides between the two. 295,295 are provided.

  In addition, although not particularly illustrated, the joint protrusions 281 and 282, the filling portion 288, the gate portion 289, and the fitting portion 285 (the convex portion 285a and the concave portion 285b) provided in the second embodiment are similarly provided in the drain pipe 10B. It is done.

  A recess 296 is formed as a joining edge in the first divided body 21B. The second divided body 22 </ b> B is provided with a bonding protrusion 2950 that is inserted into the recess 296 as a bonding edge. The joint protrusion 2950 is configured by the tip portion of the wall portion 295.

  At the time of molding the first divided body 21B, a primary injection gate may be provided on the inner wall surface of the concave portion 296 of the first divided body 21B. On the other hand, at the time of molding the second divided body 22B, it is preferable to provide a primary injection gate at a location corresponding to at least one of the front end surfaces of the walls 295 and 295 of the second divided body 22B. What is necessary is just to manufacture a metal mold | die so that each gate may be arrange | positioned in such a position.

  FIG. 15 is an enlarged cross-sectional view showing a part of FIG. 14 showing the drain pipe 10B before the secondary injection according to the third embodiment.

  As shown in FIG. 15, the joining protrusion 2950 of the second divided body 22 </ b> B is inserted into the concave portion 296 of the first divided body 21 </ b> B and the mold is closed by the moving process. The remaining space in the recess 296 in which the bonding protrusion 2950 is inserted becomes a filling portion of the resin material for secondary injection. The first divided body 21B is formed with at least one gate portion (not shown) that penetrates to the filling portion. A resin material for secondary injection is injected into the filling portion through this gate portion.

  In the third embodiment, a rib 2951 is provided at an end portion of the joining projection 2950 that contacts the recess 296. In the joining step, the resin material for secondary injection is injected through the gate portion, and the resin material 297 for secondary injection is filled in the filling portion as shown in FIG. The concave portion 296 of 21B and the joint protrusion 2950 of the second divided body 22B are joined. At this time, since the bonding protrusion 2950 has the rib 2951, the resin material 297 is suppressed from protruding from the filling portion.

  That is, when the bonding protrusion 2950 does not have the rib 2951, as shown in FIG. 17, when the filling material is filled with the resin material 297 for secondary injection, the pressure between the resin materials 297 causes the gap between the inner wall surfaces of the recesses 296. It spreads and a gap is formed between the inner wall surface of the recess 296 and the outer surface of the bonding projection 2950, and the resin material 297 passes through the gap and the excess resin material 2971 protrudes from the recess 296.

  On the other hand, in the third embodiment, the filling material is filled with the resin material 297 for secondary injection, and the force between the ribs 2951 is applied in addition to the force between the inner wall surfaces of the recesses 296 due to the pressure of the resin material 297. . For this reason, a gap is not easily formed between the inner wall surface of the recess 296 and the outer surface of the bonding projection 2950, and the resin material 297 is unlikely to protrude from the recess 296.

(Other)
As mentioned above, although the insert molding apparatus concerning the present invention was explained based on an embodiment, the present invention is not limited to the above-mentioned embodiment.

  For example, in the above-described embodiment, the joint portion 23 is formed by performing a second injection of a resin material on the joint edges 212 and 222 of the first divided body 21 and the second divided body 22 in the joining step. The case where it shape | molds and the joining edges 212 and 222 are joined is illustrated. However, in the joining step, the joining edges 212 and 222 may be joined together by thermally welding the joining edges 212 and 222 of the first divided body 21 and the second divided body 22. By adopting so-called HP-DSI (hot plate DSI) in the joining process, secondary injection becomes unnecessary and the die can be simplified.

  Further, in the above embodiment, gaps (first gaps 24 and 25, second gaps 26 and 27) are formed between the outer walls of the flow path 11 facing each other by the first bent portion 114 and the second bent portion 115. The drainage pipe 10 thus made has been described as an example. However, it may be a drain pipe in which the outer walls are close to each other and there is no gap.

  Further, in the above embodiment, the case where the resin material in the primary injection and the resin material in the secondary injection are the same is illustrated, but the resin material in the primary injection and the resin material in the secondary injection are It may be different. Thereby, the freedom degree of selection of the resin material used by primary injection or secondary injection can be raised. In particular, it is possible to individually select resin materials suitable for the respective characteristics of primary injection and secondary injection.

  For example, in the secondary injection, since the resin material is poured into the space S1 having a narrower cross-sectional area than the cavities 210 and 220, the fluidity of the resin material for secondary injection may be higher than the resin material for primary injection. desired. In this case, a resin material having higher fluidity than the resin material for primary injection may be used for secondary injection. If the fluidity of the resin material for secondary injection is increased, the resin material can be supplied to the entire space S1 even if the number of the junction gates 560 is reduced.

  It is also possible to add an additive to the resin material. In order to increase the impact resistance, rubber, elastomer or the like may be added to the resin material. Further, in order to increase the bonding strength, a strength-specific grade material (filler) may be added to the resin material for secondary injection.

  Further, for example, a resin material that is difficult to be oiled such as an acrylic resin may be used.

  In addition, a form obtained by subjecting each embodiment to various modifications conceived by those skilled in the art, and a form realized by arbitrarily combining components and functions in each embodiment without departing from the gist of the present invention. It is included in the present invention.

  As is apparent from the first to third embodiments described above and the modifications thereof, the method for manufacturing the resin molded product of the first aspect joins the first divided body 21 and the second divided body 22 together. This is a method for manufacturing a resin molded product for molding the drain pipe 10 having the flow path 11. This manufacturing method includes a forming step, a moving step, and a joining step. In the molding step, the resin material is primarily injected into the cavities 210 and 220 formed by the first mold 400 and the second mold 500 to mold the first divided body 21 and the second divided body 22 individually. In the moving step, the first mold 400 and the second mold 500 are held in a state where the first divided body 21 is held by the first mold 400 and the second divided body 22 is held by the second mold 500. The joint edges 212 and 222 of the first divided body 21 and the second divided body 22 are brought closer to each other by relative movement. In the joining step, the joining edges 212 and 222 of the first divided body 21 and the second divided body 22 are joined together. At least one of the first core part 420 in the first mold 400 and the second core part 510 in the second mold 500 is provided with a texture forming part 425 for forming the texture 18 on the inner surface of the flow path.

  According to the first aspect, since the texture molding part 425 is provided in at least one of the first core part 420 of the first mold 400 and the second core part 510 of the second mold 500, the first When the divided body 21 and the second divided body 22 are formed by primary injection, the texture 18 can also be formed at the same time. Therefore, the desired texture 18 can be reliably formed on the inner surface of the flow path of the drain pipe 10 without performing a process dedicated to texture formation.

  In addition to shaping the texture 18 by the texture shaping unit 425, after joining the first divided body 21 and the second divided body 22, a plasma generating electrode is inserted into the interior to perform plasma treatment, and surface modification is performed. The texture may be formed on the inner surfaces of the first divided body 21 and the second divided body 22.

  The second aspect is realized by a combination with the first aspect. In the second aspect, in the bonding step, the resin material is secondarily injected to the respective bonding edges 212 and 222 of the first divided body 21 and the second divided body 22, thereby the bonding edges 212 and 222. They are joined together.

  According to the second aspect, the desired texture 18 can be reliably formed even when the first divided body 21 and the second divided body 22 are integrated by secondary injection of the resin material. .

  The third aspect is realized by a combination with the second aspect. In the third aspect, a concave portion 296 is formed as the joining edge in the first divided body 21 (21B), and a joining protrusion 2950 is formed as the joining edge in the second divided body 22 (22B), and the joining step Then, the joining protrusion 2950 formed in the second divided body 22 is inserted partway through the concave portion 296 formed in the first divided body 21, and the resin material is secondarily injected into the remaining space of the concave portion 296. The joining edges are joined together, and a rib 2951 is provided at an end portion of the joining projection 2950 that contacts the recess 296.

  According to the third aspect, the pressure between the ribs 2951 is applied in addition to the force between the inner wall surfaces of the recesses 296 due to the pressure of the resin material 297. For this reason, a gap is not easily formed between the inner wall surface of the recess 296 and the outer surface of the bonding projection 2950, and the resin material 297 is unlikely to protrude from the recess 296.

  The fourth aspect is realized by a combination with the second or third aspect. In the fourth aspect, the resin material in the primary injection and the resin material in the secondary injection are the same.

  According to the fourth aspect, since the same resin material is used for the primary injection and the secondary injection, the bonding strength between the first divided body 21 and the second divided body 22 and the bonding portion 23 can be increased. it can. Moreover, since the same resin material can be used, it is also possible to make the injection molding part of primary injection and secondary injection common.

  The fifth aspect is realized by a combination with the second or third aspect. In the fourth aspect, the resin material in the primary injection is different from the resin material in the secondary injection.

  According to the fifth aspect, since different resin materials are used for the primary injection and the secondary injection, the degree of freedom in selecting the resin material used for the primary injection and the secondary injection can be increased.

  In a 6th aspect, it implement | achieves by the combination with the 1st-5th aspect. In the sixth aspect, the resin molded product is the drain pipe 10 in which the hollow portion becomes the flow path 11. According to the sixth aspect, the texture 18 can be reliably formed even when the drain pipe 10 is manufactured.

  The seventh aspect is realized by a combination with the sixth aspect. In the seventh aspect, the flow path 11 has at least one bent portion (first bent portion 114 and second bent portion 115) bent in a U shape. According to the 7th aspect, the texture 18 can be reliably shape | molded also when manufacturing the drain pipe 10 which has two bending parts, such as S-shaped trap, for example.

  The eighth aspect is realized by a combination with the seventh aspect. In the eighth aspect, gaps (first gaps 24 and 25, second gaps 26 and 27) are formed between the outer walls of the flow path 11 facing each other by the bent portion. According to the 8th aspect, the 1st shaping | molding gate 450, the 2nd shaping | molding gate 550, and the joining gate 560 can be formed in the location corresponding to a clearance gap.

  The ninth aspect is realized by a combination with the eighth aspect. In the ninth aspect, the first gaps 24 and 25 and the second gaps 26 and 27 of the drain pipe 10 are formed with ribs 231 that protrude from one outer wall of the outer walls toward the other outer wall. According to the ninth aspect, the rib 231 reinforces the drain pipe 10, and the rigidity can be increased.

  The tenth aspect is realized by a combination with the ninth aspect. In the tenth aspect, the ribs 231 are connected to the outer walls. According to the tenth aspect, since the rib 231 is connected to the outer walls, the rib 231 is spanned between the first gaps 24 and 25 and the second gaps 26 and 27. Therefore, the rigidity of the entire drain pipe 10 can be further increased.

  The eleventh aspect is realized by a combination with the tenth aspect. In the eleventh aspect, the rib 231 is formed by secondary injection. According to the 11th aspect, when integrating the 1st division body 21 and the 2nd division body 22 by secondary injection, the rib 231 can also be formed simultaneously.

  The twelfth aspect is realized by a combination with the ninth to eleventh aspects. In the twelfth aspect, a first molding gate 450 and a second molding gate 550 that are gates for primary injection are provided at positions corresponding to the ribs 231. According to the twelfth aspect, the second molding gate 550 can be disposed in the vicinity of the cavity 210 for the first divided body 21, and the first molding gate in the vicinity of the cavity 220 for the second divided body 22. 450 can be arranged. Therefore, the filling balance of the resin material with respect to each cavity 210,220 can be improved, and the 1st division body 21 and the 2nd division body 22 can be shape | molded uniformly.

  The thirteenth aspect is realized by a combination with the ninth to twelfth aspects. In the thirteenth aspect, the junction gate 560 that is a gate for secondary injection is provided at a position corresponding to the rib 231. According to the 13th aspect, the filling balance at the time of shape | molding the junction part 23 can be improved, and the whole drain pipe 10 can be shape | molded uniformly.

  The fourteenth aspect is realized by a combination with the first aspect. In the fourteenth aspect, in the joining step, the joining edges of the first divided body 21 and the second divided body 22 are joined together by heat welding.

  According to the fourteenth aspect, secondary injection is not required, and the mold 300 can be simplified.

DESCRIPTION OF SYMBOLS 10 Drain pipe 11 Flow path 114 1st bending part 115 2nd bending part 18 Texture 21 1st division body 21B 1st division body 210 Cavity 212 Joining edge 22 2nd division body 22B 2nd division body 220 Cavity 222 Joining edge 231 Rib 24 1st gap 25 1st gap 26 2nd gap 27 2nd gap 2950 Joining projection 2951 Rib 296 Recessed portion 400 First mold 420 First core portion 425 Texture forming portion 450 First molding gate 500 Second mold 510 Second 2 core part 550 Second molding gate 560 Joint gate

Claims (14)

A method for producing a resin molded product for molding a resin molded product having a hollow portion by joining the first divided body and the second divided body,
A molding step of first injecting a resin material into a space formed by the first mold and the second mold, and individually molding the first divided body and the second divided body;
While the first mold is held by the first mold and the second mold is held by the second mold, the first mold and the second mold are moved relative to each other. A moving step of bringing the joint edges of the first divided body and the second divided body closer to each other;
A joining step of joining the joining edges of the first divided body and the second divided body,
In at least one of the region corresponding to the second divided body in the molding step in the first mold and the region corresponding to the first divided body in the molding step in the second mold, A method for producing a resin molded product, wherein a texture molding part for molding the texture of the inner surface of the resin molded product is provided. The joining step joins the joining edges by second-injecting a resin material to the joining edges of the first divided body and the second divided body, respectively. Manufacturing method for resin molded products. A concave portion is formed as the joining edge in the first divided body,
A joining protrusion is formed as the joining edge on the second divided body,
In the joining step, the joining protrusion formed on the second divided body is inserted partway through the recessed portion formed on the first divided body, and a resin material is secondarily injected into the remaining space of the recessed portion. By joining the joint edges,
The method for producing a resin molded product according to claim 2, wherein a rib is provided at an end portion of the joining protrusion that contacts the concave portion. The method for producing a resin molded product according to claim 2 or 3, wherein the resin material in the primary injection is the same as the resin material in the secondary injection. The method for producing a resin molded product according to claim 2 or 3, wherein the resin material in the primary injection is different from the resin material in the secondary injection. The method for producing a resin molded product according to any one of claims 1 to 5, wherein the resin molded product is a drain pipe in which the hollow portion serves as a flow path.   The said flow path is a manufacturing method of the resin molded product of Claim 6 which has at least 1 bending part bent in the U-shape. The manufacturing method of the resin molded product of Claim 7. The clearance gap is formed between the outer walls of the said flow path which opposes by the said bending part. The manufacturing method of the resin molded product according to claim 8, wherein a rib projecting from one outer wall of the outer walls toward the other outer wall is formed in the gap of the drain pipe. The method for manufacturing a resin molded product according to claim 9, wherein the rib is connected to the outer walls. The method for manufacturing a resin molded product according to claim 10, wherein the rib is formed by the secondary injection. The method for manufacturing a resin molded product according to any one of claims 9 to 11, wherein the primary injection gate is provided at a position corresponding to the rib. The method for manufacturing a resin molded product according to any one of claims 9 to 12, wherein the secondary injection gate is provided at a position corresponding to the rib. The method for producing a resin molded product according to claim 1, wherein in the joining step, the joining edges of the first divided body and the second divided body are joined together by heat welding. .