JP2018140537A - Method for manufacturing multicolor molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the man-hours of molding and to smoothly connect a boundary part of different materials.SOLUTION: A method for manufacturing a two-color molded product (11) comprises: an injection step that injects each of materials (m1, m2) at both sides of a partition plate (3) for partitioning a boundary of the materials (m1, m2), in a direction where the partition plate (3) exists; and a partition plate removing step that opens the boundary by removing the partition plate (3) from the boundary at any time point during a period when foam or vulcanization occurs in each of the materials (m1, m2) after injecting each of the materials (m1, m2).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a multicolor molded product obtained by integrally molding a plurality of different materials.

  A multicolor molded product is a molded product generally obtained by injection molding a plurality of types or colors of resin materials simultaneously or sequentially. However, here, a material of the same type or the same color is defined as a multicolor molded product as long as it is a molded product obtained by simultaneous or sequential injection molding with a plurality of injection units. From the above definition, multicolor molding is assumed to be a molding method in which a plurality of injection units are used to simultaneously or sequentially inject materials.

  As a manufacturing method of a multicolor molded product, (1) a manufacturing method using a multicolor molding machine and (2) a manufacturing method by moving a molded product between a plurality of injection molding machines are known. The method (1) includes a method of simultaneously injecting a plurality of types of materials into one mold using an injection molding machine having a plurality of injection units, a mechanism for rotating the plurality of injection units and the mold, There is a method in which a plurality of types of materials are sequentially injection-molded using an injection molding machine equipped with In the method (2), the primary molded product injection-molded by the first injection molding machine is set at a predetermined position on the mold of the injection molding machine in the next order, and injection molding is performed by the injection molding machine. This is a method for performing multicolor molding by repeating the process of setting the obtained molded product in a mold of an injection molding machine in the next order and performing injection molding.

  Patent Document 1 discloses a method for forming a laminated molded body capable of accurately molding a two-color molded body in which a part of the surface of a resin core material is covered and integrated with a skin material. In this molding method, the lower plate for mold press molding is provided with a partition plate that partitions the semi-molten resin supplied from each gate.

  Patent Document 2 discloses a method for manufacturing an automotive interior for an airbag, which is a two-color molded product. In this manufacturing method, a hard thermoplastic resin material is supplied from the injection hole of one injection plunger to the molding resin injection gate, and a soft thermoplastic resin material is supplied from the injection hole of the other injection plunger into the resin injection gate. doing.

JP-A-8-267479 (published October 15, 1996) JP 2001-97163 A (published April 10, 2001)

  However, in the molding method described in Patent Document 1, although the boundary portion of different materials is smoothly connected by using a partition plate, different materials are injection-molded in two steps. There is a problem that the number of molding steps increases.

  On the other hand, in the manufacturing method described in Patent Document 2, since different materials are injection-molded in a single process, the number of molding steps can be reduced, but different materials can be used as in the molding method described in Patent Document 1. There is a problem that consideration is not given to the point of view of smoothly connecting the boundary portions.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a multicolor molded product capable of reducing the number of molding steps and smoothly connecting boundary portions of different materials. There is to do.

  In order to solve the above problems, a method for manufacturing a multicolor molded product according to an aspect of the present invention is a method for manufacturing a multicolor molded product obtained by integrally molding a plurality of different materials, An injection step of injecting each of the plurality of different materials in the direction in which the partition plate exists, and injecting each of the plurality of different materials, A partition plate removing step of removing the partition plate from the boundary and opening the boundary at any point in time during which foaming or vulcanization is occurring in each of a plurality of different materials. .

  According to the above method, in the injection step, each of the plurality of different materials is injected in the direction in which the partition plate exists, with the partition plate for partitioning the boundaries between the plurality of different materials interposed therebetween. For this reason, each of several different material can be inject | emitted with one process. Thereby, compared with the method of dividing each of a plurality of different materials into a plurality of processes and performing injection molding, the number of molding steps can be reduced. Further, according to the above method, in the partition plate removing step, after injecting each of the plurality of different materials, at any point in time during which foaming or vulcanization occurs in each of the plurality of different materials Remove from the boundary to release the boundary. For this reason, it is possible to smoothly connect the boundary portions of different materials by forming a plurality of different materials in parallel and adapting the boundary portions of the plurality of different materials. As described above, according to the above method, it is possible to reduce the number of molding steps and smoothly connect the boundary portions of different materials.

  In the method for manufacturing a multicolor molded product according to one aspect of the present invention, the plurality of different materials may be two different materials. According to the above method, it is possible to manufacture a two-color molded product in which the boundary portions of different materials are smoothly connected.

  In the method for producing a multicolor molded product according to one aspect of the present invention, the taper angle of each of the two side surfaces extending along the extending direction of the boundary in the partition plate is more than 0 degree and not more than 1 degree. Preferably there is. According to the above method, the partition plate can be moved smoothly.

  In the method for producing a multicolor molded product according to one aspect of the present invention, when the partition plate is lowered, one of the two side surfaces extending along the extending direction of the boundary in the partition plate, and the plurality of the plurality of side surfaces It is preferable that the width of the gap along the injection direction formed between the different materials and the material adjacent to one of the side surfaces is greater than 0 mm and equal to or less than 0.05 mm. According to the above method, continuous injection can be made possible by avoiding clogging due to material entering the gap.

  According to the method for manufacturing a multicolor molded product according to one aspect of the present invention, it is possible to reduce the number of molding steps and to smoothly connect the boundary portions of different materials.

It is a perspective view which shows the structure of the molding machine which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the longitudinal cross-section of the said molding machine. (A) is a perspective view showing the state of a two-color molded product when a plurality of materials are injected in the direction in which the partition plate exists, and (b) is a cross-sectional view of the two-color molded product. (c) is a perspective view showing the state of the two-color molded product when the partition plate is lowered, (d) is a diagram for explaining the taper angle of the side surface of the partition plate, and (e) It is a figure for demonstrating the width | variety of the clearance gap made between the side surface of a partition plate, and the material which adjoins the side surface. (A) is a figure which shows an example of the structure of the two-color molded product which concerns on one Embodiment of this invention, (b) is sectional drawing which shows the structure of the cross section of the said two-color molded product.

  The embodiment of the present invention will be described with reference to FIGS. Hereinafter, for convenience of explanation, components having the same functions as those described in a certain item may be denoted by the same reference numerals in other items, and the description thereof may be omitted.

[Molding machine structure]
FIG. 1 is a perspective view showing the structure of a molding machine 100 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing a longitudinal sectional structure of the molding machine 100. As shown in these drawings, the molding machine 100 includes an upper mold 1, a lower mold 2, a partition plate 3, a pot 4, a plunger 5, a hydraulic cylinder 6, a nozzle 7, and a nozzle 8.

  On the lower surface of the upper mold 1, a mold for forming a substantially upper half of a two-color molded product (multicolor molded product) 11 manufactured by the molding machine 100 is engraved. In addition, a mold for forming a substantially lower half of the two-color molded product 11 is engraved on the upper surface of the lower mold 2.

  By joining the lower surface of the upper mold 1 and the upper surface of the lower mold 2 and injecting the material m1 from the nozzle 7 described later in the mold and injecting the material m2 from the nozzle 8 in the mold, A two-color molded product 11 in the middle of molding in a state where the boundary between the material m1 and the material m2 is partitioned by the partition plate 3 is formed. The two-color molded product 11 is a molded product that is molded integrally by combining a plurality of different materials m1 and m2. An injection port 10 is formed above the upper mold 1, and the material m 1 is injected through the injection port 10.

  Examples of the combination of the material m1 and the material m2 include a combination of a solid molding material and a sponge molding material, and a hard molding material and a soft molding material (for example, an olefin elastomer). The combination of these can be illustrated.

  In the present embodiment, a method of forming the two-color molded article 11 in which a plurality of different materials are two different materials m1 and m2 will be described, but the method to which the present invention can be applied is not limited to this, for example, The present invention can also be applied to a method for forming a multicolor molded product in which three or more different materials are combined and molded integrally.

  An opening h is formed on the front side of the joint between the upper mold 1 and the lower mold 2, and the two-color molded product 11 is taken out through the opening h. Further, a handle 3 a for lowering the partition plate 3 protrudes from a hole formed in a lower portion of the opening h on the side surface on the near side of the lower mold 2.

  The partition plate 3 is a plate-like member for partitioning boundaries between a plurality of different materials m1 and materials m2. The pot 4 is a substantially cylindrical member formed by extending a circular hole centering on a point on the central axis along the central axis, and one end of the pot 4 is connected to the nozzle 8. One end of the nozzle 8 is connected to the hole of the pot 4. The material m2 is injected from the injection portion of the nozzle 8 by putting the material m2 into the hole of the pot 4 and pushing it with the plunger 5. The plunger 5 is pushed into the hole of the pot 4 by pressing of the hydraulic cylinder 6. On the other hand, the material m1 is injected from the injection portion of the nozzle 7.

[Method for producing two-color molded product]
The manufacturing method of the two-color molded product 11 of the present embodiment using the molding machine 100 described above includes at least the following steps (1) and (2).
(1) An injection step of injecting each of the material m1 and the material m2 in the direction in which the partition plate 3 exists with the partition plate 3 for partitioning the boundary between the material m1 and the material m2 interposed therebetween.
(2) After injecting each of the material m1 and the material m2, the partitioning is performed at any point in time during which foaming or vulcanization is occurring in each of the material m1 and the material m2 (for example, 30 seconds after the start of injection). A partition plate removing step of removing the plate 3 from the boundary to open the boundary (more specifically, lowering the partition plate 3).

  By incorporating the two nozzles 7 and 8 into the mold in the molding machine 100 described above, each of the material m1 and the material m2 is injected in one step by the injection step (1). be able to. Thereby, compared with the method of dividing each of the material m1 and the material m2 into two processes and performing injection molding, the number of molding steps can be reduced.

  Moreover, the boundary part of the material m1 and the material m2 is made smooth by forming the material m1 and the material m2 simultaneously and in parallel by the partition plate removing step of (2) above, and making the boundary part of the material m1 and the material m2 familiar. Can be produced. As described above, according to the above method, the molding steps can be reduced by realizing simultaneous molding of the material m1 and the material m2 in one step, and the boundary portion between the material m1 and the material m2 can be smoothly connected without a gap. be able to.

  Further, according to the above method, only one molding machine 100 is used, and the material m1 and the material m2 can be simultaneously molded within 180 seconds which is a normal molding time. Thereby, the total molding time can be halved as compared with the method in which each of the material m1 and the material m2 is divided into two processes and injection-molded. In addition, in the conventional method of injection molding divided into two steps, two molding machines or dedicated machines are required, and there is a problem that additional equipment investment is required, but according to the above method, Such a problem does not occur.

[About the state of two-color molded products during molding]
Next, the state of the two-color molded product 11 in the middle of molding will be described with reference to FIG. FIG. 3A is a perspective view showing a state of the two-color molded product 11 when each of the material m1 and the material m2 is injected in the direction in which the partition plate 3 exists. FIG. 3B is a cross-sectional view of the two-color molded product 11 in the state shown in FIG.

  FIG. 3B shows a two-color molded product when each of the material m1 and the material m2 is injected in the direction in which the partition plate 3 exists with the partition plate 3 for partitioning the boundary between the material m1 and the material m2 interposed therebetween. 11 states are shown.

  FIG. 3C is a perspective view showing a state of the two-color molded product 11 when the partition plate 3 is lowered. FIG. 3 (c) shows a state in which foaming or vulcanization occurs in each of the material m1 and the material m2 after the material m1 and the material m2 are respectively injected in the injection process described above. The state when the partition plate 3 is lowered is shown.

  Next, the taper angle of the side surface of the partition plate 3 will be described with reference to FIG. As shown in the figure, the taper angles θ of the two side surfaces SUF1 and SUF2 extending along the extending direction of the boundary BD in the partition plate 3 are preferably more than 0 degree and less than 1 degree. . If this condition is satisfied, the partition plate 3 can be moved smoothly when the partition plate 3 is lowered.

  Next, based on (e) of FIG. 3, the width | variety of the clearance gap formed between the side surface of the partition plate 3 and the material which adjoins the side surface is demonstrated. As shown in the figure, when the partition plate 3 is lowered, the injection direction formed between the side surface SUF1 extending along the extending direction of the boundary BD in the partition plate 3 and the material m2 close to the side surface SUF1. It is preferable that the width d of the gap along the line exceeds 0 mm and is 0.05 mm or less. Similarly, when the partition plate 3 is lowered, the side surface SUF2 extending along the extending direction of the boundary BD in the partition plate 3 and the injection direction formed between the material m1 adjacent to the side surface SUF2 are aligned. The width d of the gap is preferably more than 0 mm and not more than 0.05 mm. If the above conditions are satisfied, continuous injection can be made possible by avoiding clogging due to material entering the gap.

[About the structure of two-color molded products]
Next, based on FIG. 4, the structure of the two-color molded product 11 manufactured by the method described above will be described. (A) of FIG. 4 is a figure which shows an example of the structure of the two-color molded product 11 manufactured with the method mentioned above. On the other hand, FIG. 4B is a cross-sectional view of the two-color molded product 11 shown in FIG.

  As shown in FIG. 4A, the joint portion J1, which is a boundary portion between the material m1 and the material m2 of the two-color molded article 11, is a portion formed by opening the partition plate 3, and the boundary portion is a gap. It has a structure that connects smoothly. Further, in the two-color molded article 11 manufactured by the above-described method, as shown in FIG. 4B, the position of the boundary surface (joint portion J1) between the material m1 and the material m2 is clear even in the cross section. It becomes a structure that can be specified.

  Each of the joint portion J2 and the joint portion J3 is a boundary portion that can be inevitably formed by being partitioned by the inner walls on the front and back side surfaces of the upper mold 1 and the lower mold 2 shown in FIG. This is different from the boundary portion formed by opening the partition plate 3 described above.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

3 Partition plate 3a 11 Two-color molded product (multicolor molded product)
BD boundary θ taper angle d width m1 material m2 material SUF1 side SUF2 side

Claims (4)

A method for producing a multicolor molded product obtained by integrally combining a plurality of different materials,
An injection step of injecting each of the plurality of different materials in the direction in which the partition plate exists, with a partition plate for partitioning the boundaries between the plurality of different materials,
After injecting each of the plurality of different materials, the partition plate is removed from the boundary to open the boundary at any point in time during which foaming or vulcanization occurs in each of the plurality of different materials. And a partition plate removing step.   The manufacturing method according to claim 1, wherein the plurality of different materials are two kinds of different materials.   3. The method according to claim 1, wherein a taper angle of each of the two side surfaces extending along the extending direction of the boundary in the partition plate is greater than 0 degree and equal to or less than 1 degree. .   When the partition plate is lowered, between one of the two side surfaces extending along the extending direction of the boundary in the partition plate, and a material close to one of the side surfaces among the plurality of different materials. The manufacturing method according to any one of claims 1 to 3, wherein a width of the gap along the direction of injection that can be reduced exceeds 0 mm and is 0.05 mm or less.

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