JP6614432B2 - Manufacturing method of molded products - Google Patents

Description

  The present invention relates to a method for manufacturing a molded product in which a thermoplastic resin sheet (single wall molded body) and a core material are integrated, and particularly relates to a technique for preventing deformation such as warpage.

  As exterior sheets used for interior walls of buildings, partitions, ceilings, floors, doors, housings for electronic devices, interior materials for vehicles such as automobiles, wall materials for cold storage beds, wall materials for refrigerators and refrigerators, containers for cold storage, etc. Plastic molded products having high strength and rigidity and excellent heat insulation and sound insulation are widely used. As such a molded product, for example, a foam with an exterior formed by molding a decorative plastic sheet (film) by sheet insert molding, a molded body filled with a foamed resin after a surface wall is previously molded, and the like are known.

  However, these molded products are not formed by molding the thermoplastic resin sheet and the foam in the mold at the same time, even if the exterior material or the surface wall is formed on the surface of the foam. There is a problem that it is difficult to shorten the cost and low cost is difficult. Further, for example, when the surface wall is formed of an insert, there is a problem that the bonding strength due to fusion with the foam is weak.

  Under such circumstances, the applicant of the present application has proposed a new plastic composite molded body that can shorten the molding cycle, obtain a lightweight, low-cost molded body, and a manufacturing method thereof ( (See Patent Document 1).

  Patent Document 1 proposes a method of manufacturing a molded product that can shorten a molding cycle and can obtain a molded product that is lightweight and has high strength and rigidity. In the manufacturing method, The thermoplastic resin sheet extruded from the extrusion head is placed in a pair of split molds. Vacuum is sucked from the cavity surface of the mold, air is introduced into the mold to mold the thermoplastic resin sheet into a shape along the cavity of the mold, and pre-expanded resin particles are filled into the mold. The particles are fused together by blowing heated steam. The thermoplastic resin sheet is extruded in a molten state, vacuumed from the cavity surface of the mold, and air is introduced into the mold to mold the thermoplastic resin sheet.

JP 2006-68930 A

  However, the manufacturing method described in Patent Document 1 is desired to be improved, for example, the use of steam is large in terms of equipment. Also, in the molding that integrates the thermoplastic resin sheet and foam, the resin temperature on the side in contact with the core material such as foam does not drop completely after taking out from the mold, and deformation such as warping and wavy phenomenon occur The big problem of doing is left.

  The present invention has been made in view of the above-described conventional situation, and can form a lightweight and high-strength molded article with a short molding cycle and simple equipment, and suppress defects due to deformation such as warpage and undulation. An object of the present invention is to provide a method for producing a molded product that can be used.

In order to achieve the above-described object, the method for producing a molded article of the present invention arranges a pair of molten resin sheets between a pair of molds, and arranges a pair of core materials between these molten resin sheets, By clamping the mold, the pair of molten resin sheets are sandwiched between the pair of core materials in a state having a space therein , and the pair of molten resin sheets are welded at least at a part of the periphery of the core material. Then, a pair of molded products in which each molten resin sheet and the core material are integrated are molded in a state of being coupled to each other, and the molded product is taken out from the mold and divided into the molded products. Alternatively, a pair of molten resin sheets are disposed between a pair of molds, a pair of core materials are disposed between the molten resin sheets, and the pair of core materials are sandwiched between the pair of molten resin sheets. The mold is clamped with an insertion member interposed between the core materials, and a pair of molten resin sheets are welded at least partially around the core material, so that each molten resin sheet and the core material are integrated. The paired molded products are molded in a state of being coupled to each other, and the molded product is taken out from the mold and divided into the molded products.

  The manufacturing method according to the present invention is a method of performing batch molding in a state where a pair of molded products are joined, and the molding efficiency is greatly improved. Further, during and after the molding of the pair of molded products, the molded products are supported with each other, and deformation such as warpage and undulation is effectively suppressed. In particular, if the insertion member is inserted between the core members, the core member is pressed and supported from behind by the insertion member, and the deformation is greatly suppressed. Furthermore, in this invention, since it is the structure which inserts a core material and integrates with a thermoplastic resin sheet, it is not necessary to use a steam etc., and capital investment is also suppressed.

  According to the present invention, a lightweight and high-strength molded product can be molded efficiently and with simple equipment, and defects due to deformation such as warpage and undulation can be suppressed.

It is a schematic sectional drawing which shows the manufacturing process of the molded article to which this invention is applied, and shows the supply process of a thermoplastic resin sheet. It is a schematic sectional drawing which shows the shaping process by the metal mold | die of a thermoplastic resin sheet. It is a schematic sectional drawing which shows the assembly process of a core material and an insertion member. It is a schematic sectional drawing which shows the process of inserting a core material and an insertion member. It is a schematic sectional drawing which shows the mold clamping process of a metal mold | die. It is a schematic sectional drawing which shows the taking-out process of a molded article. It is a schematic sectional drawing which shows the division | segmentation process of a molded article. It is a schematic sectional drawing which shows the example of a form of the shape | molded molded article. It is a schematic sectional drawing which shows the other manufacturing process of a molded article, and shows the process of inserting a core material. It is a schematic sectional drawing which shows the mold clamping process of a metal mold | die. It is a schematic sectional drawing which shows the taking-out process of a molded article.

  Hereinafter, an embodiment of a method for producing a molded article of the present invention will be described in detail with reference to the drawings.

  The molded product manufactured by the manufacturing method of the present embodiment has a single wall structure in which a single thermoplastic resin sheet (molten resin sheet) is molded, and the core material is joined and integrated.

  The thermoplastic resin used for the thermoplastic resin sheet is not particularly limited and may be any one as long as it can be molded. For example, polyolefin such as polyethylene resin or polypropylene resin Other than resin, ethylene-vinyl acetate copolymer, vinyl chloride resin, ABS resin (acrylonitrile-styrene-butadiene resin), polyamide resin, polystyrene resin, polyester resin, polycarbonate resin, engineering plastics such as modified polyphenylene ether, etc. are suitable It is also possible to add fillers such as glass fiber, carbon fiber, calcium carbonate, talc, mica, etc. as necessary.

  Arbitrary things can be used as a core material, for example, a foam can be used. The foam is obtained by foam-molding various resin materials, and examples of the resin material include polyethylene resins and polypropylene resins. As the polyethylene resin, low density polyethylene (LDPE), high density polyethylene (HDPE), linear short chain branched polyethylene (LLDPE), and the like can be used. Copolymerization of ethylene and other copolymerizable monomers It may be a coalescence. Examples of the polypropylene resin include a propylene homopolymer, a random or block copolymer of propylene and another α-olefin (such as ethylene, butene, pentene, hexene, octene, and methylpentene). In any case, it is preferable to contain polyethylene or polypropylene having a long-chain branched structure. Alternatively, it is also possible to use a foam of polyacrylonitrile / styrene copolymer (so-called heat pole).

  Of course, not only this but the foam which consists of arbitrary resin materials can be used. Moreover, the core material does not necessarily need to be a foam, and a non-foamed material can be used as the core material.

  Next, a method for manufacturing the above-described molded product will be described. In the manufacturing method of the present embodiment, two molded products are simultaneously molded in a back-to-back state, and each molded product is pressed down by interposing an insertion member therebetween. It is intended to suppress the occurrence of phenomena such as undulations.

  In this embodiment, in order to manufacture a molded product in which a thermoplastic resin sheet and a core material are integrated, first, as shown in FIG. 1, a pair of molten thermoplastics extruded from the resin extrusion heads 1 and 2 are used. Resin sheets (molten resin sheets) 3 and 4 are supplied between a pair of molds 5 and 6, and as shown in FIG. Shape along the cavity. The surfaces of the molds 5 and 6 that contact the thermoplastic resin sheets 3 and 4 are set as ventilation contact surfaces, and vacuum suction is performed on the ventilation contact surfaces so that the thermoplastic resin sheets 3 and 4 follow the mold cavity. Shaped into shape.

  On the other hand, as shown in FIG. 3, the core materials 7 and 8 and the insertion member 9 are prepared and integrated beforehand. As described above, the core materials 7 and 8 are made of a resin foam or the like, and are formed so as to coincide with the shapes of the thermoplastic resin sheets 3 and 4 that have been shaped in advance. The insertion member 9 has a shape that fits into the irregularities of the thermoplastic resin sheets 3 and 4 and the core materials 7 and 8 in the molds 5 and 6, and when the molds 5 and 6 are closed. The space between the core materials 7 and 8 is filled. That is, the insertion member 9 is formed to have a large diameter corresponding to the retreat of the core materials 7 and 8, the center portion 9 a that abuts against the thermoplastic resin sheets 3 and 4, and both sides corresponding to the recessed shapes of the core materials 7 and 8. The side portions 9b and 9c enter into the recesses of the core materials 7 and 8, and are in close contact with the core materials 7 and 8.

  After shaping the thermoplastic resin sheets 3 and 4, as shown in FIG. 4, the integrated core materials 7 and 8 and the insertion member 9 are inserted by a robot or the like. At this time, the core materials 7 and 8 and the insertion member 9 integrated with each other are brought into close contact with a thermoplastic resin sheet (for example, the thermoplastic resin sheet 3) formed in one mold (for example, the mold 5). The robot is inserted and placed in the mold, and then the mold is clamped.

  The insertion member 9 is preferably formed to be slightly larger than the space between the core materials 7 and 8, thereby pressing the core materials 7 and 8 when the molds 5 and 6 are closed. It becomes possible. The insertion member 9 is preferably formed of a foam material for the purpose of imparting an appropriate pressing force, but is not limited thereto. Examples of the foam material include foamed polystyrene. Expanded polystyrene is an inexpensive material and can be reused by removing the insertion member 9 after molding.

  After the insertion of the core members 7 and 8 and the insertion member 9, as shown in FIG. 5, the molds 5 and 6 are closed and clamping is performed. Thereby, the thermoplastic resin sheets 3 and 4 and the core materials 7 and 8 are heat-welded and integrated. At the same time, the end portions of the thermoplastic resin sheets 3 and 4 are thermally welded to at least a part (for example, the entire circumference) of the periphery of the core materials 7 and 8 so that a pair of molded products are joined. At this time, since an appropriate pressing force is applied from behind the core materials 7 and 8 by the insertion member 9, the entire surfaces of the core materials 7 and 8 are pressure-bonded to the thermoplastic resin sheets 3 and 4 without unevenness, which is favorable. A heat-welded state is realized.

  Next, the molds 5 and 6 are opened, and the molded body is taken out as shown in FIG. At this stage, the two molded products are in an integrated state. That is, in a state where the first molded product in which the thermoplastic resin sheet 3 and the core material 7 are integrated and the second molded product in which the thermoplastic resin sheet 4 and the core material 8 are integrated are integrated. It is taken out.

  In molding to integrate the core material made of thermoplastic resin sheet and foam material, the resin temperature at the part in contact with the core material, which is the foam material, cannot be lowered even after taking out from the mold, which causes warpage and undulation. Such deformation may occur.

  On the other hand, in the state in which the two molded products are integrated, an appropriate pressing force is applied from the back of the core materials 7 and 8 by the insertion member 9 even after taking out from the molds 5 and 6. Even if it tries to deform, such as warping or undulation, it is pressed down and cannot be deformed. Thereby, generation | occurrence | production of deformation | transformation, such as curvature and a wave, is suppressed.

  The taken out molded product is divided into each molded product after cooling. For example, as shown in FIG. 7, the division may be performed by cutting along a one-dot chain line in the drawing and dividing into two. At this time, if the insertion member 9 is formed of foamed polystyrene, the insertion member 9 can be cut together, and the insertion member 9 can be removed after cutting. Alternatively, the first molded product in which only the thermoplastic resin sheets 3 and 4 are cut and the thermoplastic resin sheet 3 and the core material 7 are integrated, and the first molded product in which the thermoplastic resin sheet 4 and the core material 8 are integrated. It is possible to separate the molded product 2 and to take out the insertion member 9. In this case, since the insertion member 9 remains in its original form, it can be reused.

  Alternatively, instead of cutting, a first molded product in which the thermoplastic resin sheet 3 and the core material 7 are integrated and a second molded product in which the thermoplastic resin sheet 4 and the core material 8 are integrated are drawn. It is also possible to separate by peeling. Since the two molded products are merely joined to each other at the end surfaces of the thermoplastic resin sheets 3 and 4, they can be easily peeled off by applying an external force. In this case, since the peeled surface is likely to be a rough surface, it is preferable to perform some post-processing (polishing or the like) after the separation to smooth the surface.

  FIG. 8 shows a molded article 10 to be manufactured. The molded product 10 manufactured by the manufacturing method of this embodiment is excellent in the integrity of the thermoplastic resin sheets 3 and 4 and the core materials 7 and 8, and is suppressed to the minimum deformation such as warpage and undulation.

  In the above-described embodiment, the insertion member 9 is inserted behind the core members 7 and 8 to suppress the occurrence of deformation such as warpage and undulation. However, the effect of suppressing the deformation even if the insertion member 9 is omitted. Can be obtained. Hereinafter, the manufacturing process when the insertion member 9 is not inserted will be described.

  In this case, as shown in FIG. 9, a pair of molten resin sheets (thermoplastic resin sheets 3, 4) are disposed between the pair of molds 5, 6, and the thermoplastic resin sheets 3, 4 are interposed between them. A pair of core materials 7 and 8 are arranged. The core members 7 and 8 are inserted so as to be in contact with the thermoplastic resin sheets 3 and 4 by, for example, a robot. The pair of core materials 7 and 8 may be of a size that abuts each other or may not be abutted, but since a pressing force is applied when the molds 5 and 6 are clamped, It is preferable that the core members 7 and 8 abut each other.

  Next, as shown in FIG. 10, the molds 5 and 6 are clamped, and the thermoplastic resin sheets 3 and 4 and the core materials 7 and 8 are thermally welded and integrated. At the same time, the end portions of the thermoplastic resin sheets 3 and 4 are thermally welded around the entire circumference of the core materials 7 and 8, and the pair of molded products are formed in a combined state.

  Next, the molds 5 and 6 are opened, and the molded product is taken out as shown in FIG. 11. At this stage, the end portions of the thermoplastic resin sheets 3 and 4 are heat-welded to integrate the two molded products. It is in the state. The two molded products are integrated in this way, and the molded products are taken out from the molds 5 and 6 so that the molded products support each other during the cooling period after being molded and taken out from the molds 5 and 6. And the deformations are suppressed to each other. It is the same as in the previous embodiment that it is taken out from the molds 5 and 6 and cooled and then separated into two molded products.

  As mentioned above, although embodiment which applied this invention has been described, this invention is not limited to this embodiment, and it cannot be overemphasized that a various change is possible in the range which does not deviate from the summary of this invention. .

  According to the manufacturing method of the present invention, when the mold is clamped or after being taken out of the mold, the molded products support each other, or an appropriate pressing force is applied to the core materials 7 and 8, It is possible to produce a molded product without deformation such as warpage and undulation. Further, the apparatus configuration is only a mold, and expensive equipment is unnecessary. Further, when the insertion member 9 is used, if it is reused, the manufacturing cost is not increased.

1, 2 Resin extrusion heads 3 and 4 Thermoplastic resin sheets 5 and 6 Molds 7 and 8 Core material 9 Insertion member 10 Molded product

Claims (5)

While arranging a pair of molten resin sheets between a pair of molds, arranging a pair of core materials between these molten resin sheets,
By clamping the mold, the pair of molten resin sheets are sandwiched between the pair of core materials in a state having a space therein , and the pair of molten resin sheets are welded at least at a part of the periphery of the core material. A molded product characterized in that a pair of molded products in which each molten resin sheet and the core material are integrated are molded in a state of being coupled to each other, and this is taken out of the mold and divided into each molded product. Method.   The method for producing a molded product according to claim 1, wherein a pair of molten resin sheets are welded around the entire circumference of the core material. While arranging a pair of molten resin sheets between a pair of molds, arranging a pair of core materials between these molten resin sheets,
The pair of molten resin sheets are sandwiched between the pair of molten resin sheets, an insert member is interposed between the pair of core materials, and the mold is clamped, and the pair of molten resin sheets is at least partially around the core material. Is formed by bonding a pair of molded products in which each molten resin sheet and the core material are integrated with each other, and taking them out of the mold and dividing them into the molded products. Manufacturing method of molded products.   4. The method of manufacturing a molded product according to claim 3, wherein each core member is pressed by the insertion member when the mold is clamped and taken out from the mold.   The method for manufacturing a molded product according to any one of claims 1 to 4, wherein the core material is a foam.

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