JP2018171751A - Foamed resin molded article and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed resin molded article having a resin film and a manufacturing method of the same, capable of sufficiently suppressing warping of a molded article which can occur due to a difference in shrinkage factor between a resin film and a foamed resin molded article at a time of molding.SOLUTION: The foamed resin molded article includes: a front portion made of a resin film; a back portion; and a foam portion interposed between the front portion and the back portion. The front portion is inserted into the foamed portion. In the foam molding of the foamed portion, a shrinkage factor of the front portion and the back portion is smaller than a shrinkage factor of the foam portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foamed resin molded body and a method for producing the same.

  For example, a molded body made of a foamed resin, that is, a foamed resin molded body, is used for a vehicle instrument panel from the viewpoint of weight reduction. This foamed resin molding is obtained by placing a molding material containing a foaming agent in a resin material such as polypropylene or acrylonitrile-butadiene-styrene copolymer resin (hereinafter referred to as ABS resin) in a cavity of a molding die having a movable mold. After injection filling, it can be molded by a core back method or a short shot method. The foamed resin molded body thus molded has a porous foam layer formed by foaming a foaming agent. That is, since the inside of the foamed resin molded body has a relatively low density, it is lighter than a solid resin molded body having no foamed layer.

  Further, from the viewpoint of improving the design of the surface of the foamed resin molded body, a resin film or a skin is also conventionally laminated on this surface. As a method for producing a foamed resin molded body having a resin film, for example, in the above-described core back method, there is a method of using an insert molding method in which a resin film is inserted into a foamed resin molded body. An in-mold method can also be used.

  However, when the above-described insert molding method is used, there is a problem in that the molded product warps after molding because the shrinkage rate of the resin film and the foamed resin molded body at the time of molding differ greatly.

  For example, Patent Document 1 discloses a foamed resin molded body in which a transparent resin portion made of a dense resin layer and a foamed resin portion having a rough resin layer are formed as a two-color molded body. In Patent Document 1, a primary injection molding process for molding a transparent resin part with a first molding die, and a secondary injection molding process for molding a foamed resin part between the molded transparent resin part and the second molding die. And a method of controlling the mold surface temperature on the transparent resin portion side and the mold surface temperature on the foamed resin portion side of the second mold to a predetermined temperature difference is disclosed. Accordingly, in the foamed resin molded body, the transparent resin portion side and the opposite side of the transparent resin portion are contracted almost equally, and the occurrence of warpage in the foamed resin molded body is suppressed.

International Publication No. 2011/074041 Specification

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molded resin product having a resin film, which can occur due to a difference in shrinkage between the resin film and the foamed resin molded product during molding. It is providing the foaming resin molding which can fully suppress curvature, and its manufacturing method.

  In order to solve the above-mentioned problems, a foamed resin molded article of the present invention comprises a front part made of a resin film, a back part, and a foamed part interposed between the front part and the back part. The foamed resin molded body with the front part inserted therein is characterized in that the shrinkage rate of the front part and the back part is smaller than the shrinkage rate of the foamed part when foaming the foamed part.

  In addition, another foamed resin molded body of the present invention includes a front part made of a resin film, a back part, and a foamed part interposed between the front part and the back part, with respect to the back part and the foamed part. The front part is a foamed resin molded body, and the back part is a resin part denser than the foamed part.

  Moreover, the manufacturing method of the foamed resin molding of the present invention uses a foaming mold having a first mold having a first mold surface and a second mold having a second mold surface facing the first mold surface. A back portion forming step of injecting a resin material into the first cavity defined between the first mold surface and the second mold surface to form a back portion, and the back portion being placed on the second mold surface , An insert step of disposing a front portion on the first mold surface, an injection step of injecting a foamed resin material into a second cavity defined between the front portion and the back portion, and a foamed resin in the second cavity The method includes a foaming step of foaming a material to form a molding intermediate, and a solidification step of solidifying the molding intermediate.

  The foamed resin molded article of the present invention having the above-described configuration is formed by sandwiching a foamed part made of a rough resin part between a front part and a back part made of a dense resin part. In other words, the foamed resin molded body of the present invention is configured such that the foamed part is sandwiched between the front part and the back part having a smaller shrinkage rate at the time of molding than the foamed part. Thereby, the curvature in a molded article can be suppressed effectively. Moreover, since the surface part consists of a resin film, the foamed resin molding of this invention can improve designability easily. Furthermore, according to the manufacturing method of the present invention that adopts the above-described configuration, it is possible to manufacture a foamed resin molded body that can effectively suppress warping.

It is a figure which represents typically the cross section of the foamed resin molding 1 of 1st Embodiment. It is explanatory drawing showing the back part formation process in the manufacturing method of the foamed resin molding 1 of 1st Embodiment. It is explanatory drawing showing the insert process in the manufacturing method of the foamed resin molding 1 of 1st Embodiment. It is explanatory drawing showing the injection | pouring process in the manufacturing method of the foamed resin molding 1 of 1st Embodiment. It is explanatory drawing showing the foaming process in the manufacturing method of the foamed resin molding 1 of 1st Embodiment. It is a figure which represents typically the cross section of the foamed resin molding 2 of 2nd Embodiment. It is explanatory drawing showing the insert process in the manufacturing method of the foamed resin molding 2 of 2nd Embodiment. It is explanatory drawing showing the foaming process in the manufacturing method of the foamed resin molding 2 of 2nd Embodiment. It is a figure which represents typically the cross section of the foamed resin molding 3 of 3rd Embodiment. It is explanatory drawing showing the insert process in the manufacturing method of the foamed resin molding 3 of 3rd Embodiment. It is explanatory drawing showing the temperature control process in the manufacturing method of the foaming resin molding 3 of 3rd Embodiment. It is explanatory drawing showing the foaming process in the manufacturing method of the foamed resin molding 3 of 3rd Embodiment.

  Hereinafter, the foamed resin molded article of the present invention and the method for producing the same will be described with reference to preferred embodiments with reference to FIGS.

  The drawings used for explanation are schematic diagrams, and the shape, relative positional relationship, size relationship, and the like in fine portions are not necessarily described strictly. Further, unless otherwise specified, the numerical range “x to y” described in the present specification includes the lower limit x and the upper limit y in the range. And a new numerical value range can be comprised by combining these arbitrarily including those upper limit values and lower limit values and numerical values listed in the embodiments. Furthermore, numerical values arbitrarily selected from these numerical ranges can be used as upper and lower numerical values.

  Matters necessary for the implementation of the present invention other than matters specifically mentioned in the present specification can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

(First embodiment)
The foamed resin molded body 1 of the first embodiment is used for an instrument panel that is a vehicle interior part. As shown in FIG. 1, the foamed resin molded body 1 of the present embodiment includes a front part 4 made of a resin film, a back part 5, and a foamed part 6 interposed between the front part 4 and the back part 5. Have. In other words, the foamed resin molded body 1 of this embodiment is formed by laminating the front portion 4, the foamed portion 6, and the back portion 5 in this order.

  The front portion 4 corresponds to a decorative layer that improves the design of the foamed resin molded body 1, and the surface of the front portion 4 is a design surface facing the vehicle interior. The surface part 4 consists of a resin film.

  The resin film has a design layer (not shown) on the design surface side and a backing layer (not shown) on the foamed portion 6 side. The design layer is a layer on the design surface side of the resin film, and improves the design properties of the foamed resin molded body 1. The design layer may be colored or colorless and transparent. The design layer may be provided with a pattern or may be a non-patterned one. The material of the design layer is preferably a resin material, and may be a metal material. The resin material is acrylonitrile-butadiene-styrene copolymer resin (ABS resin). For example, polyolefin resins such as polypropylene, acrylic resins such as polymethyl methacrylate and polyethyl methacrylate, polyamide resins, Cellulose ester resins such as acetyl cellulose, polyester resins such as polyethylene terephthalate, cyclic hydrocarbon resins such as ethylene norbornene copolymer, poly (meth) acrylimide resins, aromatic polycarbonate resins, polyarylate resins, Examples of the resin include polymer type urethane acrylate resins and polyimide resins.

  A backing layer is a layer by the side of a foaming part among resin films, and welds the surface part 4 and the foaming part 6. FIG. The backing layer is made of the same material as the resin material of the foamed portion 6 or a material that can be welded to each other. As such a resin material, the thing similar to the resin material of the above-mentioned design layer can be illustrated, and a desired thing can be selected with the resin material of the foaming part 6. FIG. As will be described later, the backing layer is melted by the foamed resin material for molding the foamed portion 6 and then welded to the foamed portion 6 by cooling.

  The thickness of the resin film is not particularly limited, and can be any thickness as desired. For example, the thickness of the resin film is desirably 100 μm to 500 μm, and preferably 200 to 300 μm.

  The back part 5 is a part which is located on the opposite side to the front part 4 in the foamed resin molded body 1 and is not exposed to the vehicle interior. The back portion 5 in this embodiment is made of a solid resin. The back part 5 made of a solid resin is a dense resin part having no air bubbles inside. Here, the solid resin means a resin molded body made of a resin material containing no foaming agent and molded by a general injection molding method.

  The resin material of the solid resin in the embodiment is an ABS resin. However, the resin material of the solid resin is not limited to this, and may be the same material as the resin material of the foamed portion 6 or a material that can be welded to each other. As such a resin material, the thing similar to the resin material of the above-mentioned resin film can be illustrated.

  The thickness of the solid resin is not particularly limited, and can be any thickness as desired. For example, the thickness of the solid resin is desirably 100 μm to 2 mm, and preferably 500 μm to 1 mm.

  The foaming part 6 is made of a foamed resin material containing a resin material and a foaming agent. The foamed portion 6 made of a foamed resin material is a rough resin portion having a porous interior. That is, the foamed part 6 has a lower density than the front part 4 and the back part 5. Thus, the foamed part 6 which is a low density resin part contributes to the weight reduction of the foamed resin molded body 1.

  The foamed part 6 in this embodiment has a skin layer 11 on the front part 4 side and a skin layer 12 on the back part 5 side, and has a foamed layer 13 between the skin layers 11 and 12. The skin layers 11 and 12 are layers in which foaming of the foaming agent is suppressed more than the foam layer 13 at the time of molding, and are resin layers denser than the foam layer 13. The skin layers 11 and 12 are coarse resin portions having a density lower than that of the front portion 4 and the back portion 5 due to a slightly foaming foaming agent.

  In the embodiment, the molding material of the foamed portion 6 uses ABS resin as the resin material and sodium bicarbonate as the foaming agent. The combination of the resin material and the foaming agent in the molding material of the foamed portion 6 is not particularly limited. For example, the resin material is preferably a thermoplastic resin. Examples of thermoplastic resins other than ABS resin include polypropylene, polyethylene, polystyrene, polyvinyl acetate, acrylonitrile-styrene copolymer resin (so-called AS resin), acrylic resin, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyethylene terephthalate, and polybutylene. Examples include terephthalate and cyclic polyolefin. Furthermore, a fiber reinforced plastic (so-called FRP) obtained by adding a fiber material to these resin materials may be used.

  The foaming agent is not particularly limited, and a foaming agent having a suitable foaming performance and foaming temperature may be appropriately selected according to the resin material used. For example, as a foaming agent, the general thing which produces gas by being thermally decomposed can be used. Alternatively, it is possible to use a material whose volume is increased by heat.

  Common blowing agents include inorganic compounds such as sodium bicarbonate, ammonium bicarbonate and ammonium carbonate, azodicarbonamide, 2,2′-azobis9isobutyronitrile, azohexahydrobenzonitrile, and diazoaminobenzene Azo compounds such as benzenesulfonylhydrazide, benzene-1,3-sulfonylhydrazide, diphenylsulfone-3,3′-disulfonylhydrazide, diphenyloxide-4,4′-disulfonylhydrazide, 4,4′-oxybis9 ( Benzenesulfonyl hydrazide), and sulfonyl hydrazide compounds such as p-toluenesulfonyl hydrazide, N, N′-dinitrosopentamethylenetetramine, N, N′-dinitroso-N, and N′-dimethylphthalamide Nitroso compounds of terephthalic azide, and the azide compound such as p-t-butyl-benzimidazole azide and the like.

  An example of the foaming agent whose volume is increased by heat is a capsule foaming agent. The capsule foaming agent refers to a foaming agent enclosed in an outer shell made of a thermoplastic resin. Copolymers such as vinylidene chloride, acrylonitrile, acrylic acid ester, methacrylic acid ester are used as the thermoplastic resin constituting the outer shell, and isobutane, pentane, petroleum ether, hexane, heptane, low-boiling halogenation as foaming agents Volatile organic solvents such as hydrocarbons and methylsilane are used. Note that the volatile organic solvent is also called a swelling agent.

  In addition to the chemical foaming agent as described above, a physical foaming agent using a Mucell (registered trademark) process using carbon dioxide, nitrogen, or the like, or a physical foaming agent using microcapsules may be used.

  In any case, the foaming agent foams, for example, gas is generated from the foaming agent, gas is generated by a chemical reaction between the foaming agent and the foaming initiator, or the volume of the gas is increased. Bubbles are formed in the molding material. And the foamed resin molding 1 of this invention can be obtained because a bubble expand | swells or grows in a core back process.

  The addition ratio of the foaming agent to the resin material is not particularly limited. For example, the foaming agent is preferably 1.0 part by weight or more and 10.0 parts by weight or less with respect to 100 parts by weight of the resin material.

  In the foamed resin molded body 1 of the embodiment, as described above, the foamed portion 6 is sandwiched between the resin film as the front portion 4 and the solid resin as the back portion 5. By the way, since the foaming part 6 shape | molded from the resin material containing a foaming agent turns into a rough resin part, the shrinkage | contraction rate at the time of shaping | molding is larger than the resin film shape | molded from the resin material which does not contain a foaming agent. It is known. Although it depends on the resin material used, the foamed resin molded product and the resin film have a difference in shrinkage of about 2 to 4 times. In this way, when the foamed portion 6 and the resin film, which have greatly different shrinkage rates, are insert-molded, warping occurs such that the foamed portion 6 having a large shrinkage rate is on the inside and the resin film having a small shrinkage rate is on the outside. End up.

  Therefore, in the foamed resin molded body 1 of this embodiment, a solid resin having a shrinkage rate smaller than that of the foamed part 6 is provided on the back part 5 opposite to the front part 4 that is a resin film. Thus, by sandwiching both sides of the foamed portion 6 having a large shrinkage rate with a resin film and a solid resin having a shrinkage rate smaller than that of the foamed portion 6, warping caused by the difference in the shrinkage rate at the time of molding, It can be effectively suppressed. That is, the expansion of the foamed portion 6 can be physically or mechanically suppressed by sandwiching the foamed portion 6 having a large shrinkage rate from both sides with a resin film and a solid resin having a small shrinkage rate. Therefore, according to the foamed resin molded body 1 of the embodiment, it is possible to effectively suppress the warpage due to the difference in shrinkage rate during molding.

  In general, when a resin part having pores is compared with a resin part having no pores, the resin part having pores has a higher shrinkage than the resin part having no pores. In other words, a dense resin portion having a high density has a smaller shrinkage rate than a low density resin portion having a low density.

  As shown in FIG. 1, according to the foamed resin molded body 1 of the embodiment, the foamed portion 6 is a rough resin portion, and the resin film as the front portion 4 and the solid resin as the back portion 5 are dense resins. Part. Also from this, it can be said that the foamed resin molded body 1 of the embodiment has a configuration in which the foamed portion 6 having a large shrinkage rate is sandwiched from both sides by a resin film and a solid resin having a small shrinkage rate. Warpage caused by the difference in rate can be effectively suppressed.

  Moreover, it is desirable for the resin film of the front part 4 and the solid resin of the back part 5 in the said embodiment to have a shrinkage rate as close as possible, and preferably the same shrinkage rate. Thus, at the time of shaping | molding, the resin film and solid resin which pinch | interpose the foaming part 6 can suppress more effectively the curvature resulting from the difference in shrinkage | contraction rate by shrinkage | contraction rate as close as possible. Moreover, it becomes possible to suppress this curvature more effectively because the resin film and the solid resin sandwiching the foamed portion 6 have the same shrinkage rate.

  Here, the “shrinkage rate” used in the present specification means a molding shrinkage rate when the foamed foamed resin material cools and solidifies in the foamed portion 6. Further, when the back portion 5 is a solid resin in the back portion 5, it means a molding shrinkage rate when the solid resin and the foamed portion 6 are two-color molded after the solid resin is molded. In the back part 5, when the back part 5 is a resin film, it means the molding shrinkage rate at the time of insert molding. When the back portion 5 is a skin layer in the back portion 5, it means a molding shrinkage rate at the time of foam molding, similarly to the shrinkage rate of the foamed portion 6. Moreover, in the front part 4, it is the same as that of the case where the said back part 5 is a resin film.

  Further, “the shrinkage rate is the same” is used to mean that the difference between these shrinkage rates is within 0.01% to 0.1%. Thus, if the difference in shrinkage rate is within the above range, it is possible to sufficiently suppress the warpage of the foamed resin molded body due to the difference in shrinkage rate during molding.

  Next, the manufacturing method of the foamed resin molding 1 of the embodiment will be described with reference to FIGS. The method for manufacturing the foamed resin molded body 1 according to this embodiment includes the first mold 71 having the first mold surface 71a and the second mold 72 having the second mold surface 72a facing the first mold surface 71a. A foam mold 7 is used.

  In the manufacturing method, the first mold 71 is a movable mold and the second mold is a fixed mold. The first mold 71 is movable by a predetermined distance so as to approach or separate from the second mold 72 in the mold opening direction. A cavity is formed between the second mold surface 72a and the first mold surface 71a. This cavity forms the first cavity 73 in the back portion forming process described below, and forms the second cavity 74 in the insert process and the injection process. The cavity forms a third cavity 75 after the core back process. These cavity widths increase in the order of the first cavity 73, the second cavity 74, and the third cavity 75.

  The manufacturing method of the embodiment includes a back portion forming process, an insert process, an injection process, a foaming process, and a solidifying process.

  The back portion forming step is a step of forming the back portion 5 of the foamed resin molded body 1. In the back portion forming step in the embodiment, a solid resin is molded. First, the mold 7 is clamped. At this time, as shown in FIG. 2, a first cavity 73 is formed between the second mold surface 72a and the first mold surface 71a. The cavity width of the first cavity 73 is the same as the film thickness of the solid resin.

  Next, a molten resin material for molding the solid resin is injected into the first cavity 73 by an injection device and filled. At this time, the first mold 71 is clamped toward the second mold 72 with a force sufficient to maintain the size of the first cavity 73 against the fluid pressure caused by the resin material. Thereafter, the resin material is cooled and solidified by the first mold surface 71a and the second mold surface 72a, and the back portion 5 is molded.

  After the back part 5 is molded, an insert process is performed. In the insert step, the front portion 4 that is a resin film is placed in the mold 7. First, the first mold 71 is moved in the mold opening direction so that the first mold 71 and the second mold 72 are separated from the mold 7 that has been clamped in the back portion forming step.

  Thereafter, as shown in FIG. 3, the resin film prepared in advance is placed on the first mold surface 71 a while leaving the solid resin as the back portion 5 on the second mold surface 72 a, and the mold 7 is again mounted. Clamp the mold. At this time, the mold 7 that has been clamped has a second cavity 74 formed between the solid resin and the resin film. The cavity width of the second cavity 74 is smaller than the film thickness of the foamed portion 6. The resin film has a design layer disposed on the first mold surface 71a so that the backing layer is on the second cavity 74 side.

  After the insert process, an injection process is performed. In the injection step, as shown in FIG. 4, a molten foamed resin material 61 that molds the foamed portion 6 is injected and filled into the second cavity 74 defined in the mold 7. At this time, as in the case of the back portion forming step, the mold 7 that partitions and forms the second cavity 74 is clamped with a force that resists the fluid pressure of the foamed resin material 61.

  The foamed resin material 61 used in the injection step in the embodiment contains 75 parts by mass of ABS resin, 5 parts by mass of sodium hydrogen carbonate, and 20 parts by mass of talc. Of these, sodium bicarbonate functions as a blowing agent. Specifically, sodium bicarbonate is thermally decomposed to produce sodium carbonate, water, and carbon dioxide. Of these, carbon dioxide can constitute bubbles in the resin material. Moreover, since this decomposition reaction rate increases in the presence of water, foaming in the resin material by the above decomposition reaction can proceed continuously. At this time, the foaming agent generates small bubbles (fine foaming).

  As described above, a physical foaming agent using carbon dioxide, nitrogen or the like can be used instead of the chemical foaming agent. In this embodiment, these foaming agents are added in advance to the heat-melted resin material put into the mold, but instead, the resin material previously heated and melted is filled in the mold. Then, it may be added directly to the heat-melted resin material.

  The molten foamed resin material 61 injected and filled in the second cavity 74 in the injection step is heated and thus has a high temperature (for example, 140 ° C.). Therefore, the resin film backing layer disposed on the first mold surface 71 a side is melted by the foamed resin material 61 in a molten state. Similarly, the surface of the solid resin arranged on the second mold 72 side is also melted.

  In the injection step in the embodiment, after the foamed resin material 61 is injected and filled in the second cavity 74, the pressure in the second cavity 74 is maintained for a predetermined time. The pressure holding performed in the injection step is intended to form the skin layers 11 and 12 in the foamed portion 6.

  The holding pressure in the second cavity 74 is such that after the foamed resin material 61 is injected and filled into the second cavity 74, the mold is kept in a clamped state and the injection pressure is maintained as it is. Then, the surface of the foamed resin material 61 is cooled by the second mold surface 72a and the resin film. Thereby, the skin layers 11 and 12 in which the foaming agent is solidified in a finely foamed state are formed on the surface of the foamed resin material 61 filled in the second cavity 74. At this time, the foamed resin material 61 present inside the skin layers 11 and 12 is not solidified, and the foaming agent is in a slightly foamed state. Note that the holding pressure may be omitted in the injection step in the embodiment.

  A foaming process is performed after an injection | pouring process. In the foaming step, the foamed resin material 61 injected and filled in the second cavity 74 is inflated with bubbles by the foaming agent to expand the entire volume of the foamed resin material 61. Specifically, in the mold 7 having the second cavity 74, the first mold 71 is moved in the mold opening direction so as to be separated from the second mold 72, and the volume of the second cavity 74 is increased. At this time, a third cavity 75 is formed in the mold 7 as shown in FIG. The cavity width of the third cavity 75 is the same as the film thickness of the foamed portion 6.

  In this way, by increasing the volume of the second cavity 74 and forming the third cavity 75, the internal pressure in the mold 7 is lowered, and the bubbles due to the foaming agent of the foamed resin material 61 are greatly expanded. As a result, the foamed resin material 61 expands as a whole, and the molding intermediate 62 is molded.

  Then, the solidification process in which the shaping | molding intermediate body 62 is cooled and solidified is performed. In the solidification process in the embodiment, the molding intermediate 62 is cooled by the mold surface without using a cooling medium or the like. As a result, the backing layer of the resin film and the surface of the solid resin that have been melted in the pouring step are cooled and solidified and welded to the foamed resin molded body 1 respectively. Thus, the foamed resin molded body 1 including the resin film as the front portion 4 and the solid resin as the back portion 5 is formed on both surfaces of the foamed portion 6.

  At this time, since the foamed portion 6 made of the foamed resin material 61 becomes a rough resin portion, the shrinkage rate is relatively large. On the other hand, a resin film and a solid resin, which are dense resin parts, are welded to both surfaces of the foamed part 6. The dense resin portion has a relatively small shrinkage rate. That is, the foamed resin molded body 1 molded by the manufacturing method of the embodiment has a configuration in which a resin portion having a relatively high shrinkage rate is sandwiched between resin portions having a relatively low shrinkage rate. In other words, the rough resin portion is sandwiched between the dense resin portions. Therefore, it is possible to effectively suppress the warp that may occur in the foamed resin molded body 1.

  Moreover, if it is the foamed resin molding 1 of the said embodiment, it will only provide a resin film in the front part 4, and can reduce manufacturing cost compared with 2nd Embodiment mentioned later. Further, providing the back part 5 with a solid resin is advantageous for improving the strength of the foamed resin molded body 1. In this case, the strength of the foamed resin molded body 1 can be further improved by increasing the thickness of the solid resin as much as possible.

  As described above, in the manufacturing method of the present embodiment, the solid resin as the back portion 5 and the foamed portion 6 are formed by the two-color molding method, and the resin film as the front portion 4 is formed by the two-color molding. 5 and the foaming part 6 are insert-molded.

(Second Embodiment)
As shown in FIG. 6, the foamed resin molded body 2 of the second embodiment is such that the back portion 5 in the foamed resin molded body 1 of the first embodiment is the same resin film as the front portion 4. Accordingly, in the foamed resin molded body 2 of the embodiment, the foamed portion 6 is a rough resin portion, and the resin film that is the front portion 4 and the back portion 5 is the same as the foamed resin molded body 1 of the first embodiment. It is a dense resin part. That is, since the foamed portion 6 having a large shrinkage rate is sandwiched from both sides with a resin film having a low shrinkage rate, warping due to a difference in shrinkage rate during molding can be effectively suppressed.
Moreover, since the front part 4 and the back part 5 are the same resin films, they have the same shrinkage rate. That is, the foaming part 6 in the embodiment is sandwiched between the front part 4 and the back part 5 which are smaller than the shrinkage rate of the foaming part 6 and have the same shrinkage rate. Therefore, if it is the foamed resin molding 2 of the said embodiment, since the difference of the shrinkage | contraction rate of the front part 4 and the back part 5 at the time of shaping | molding will disappear, curvature can be suppressed more effectively.

  Next, the manufacturing method of the foamed resin molding 2 of 2nd Embodiment is demonstrated with reference to FIG.7 and FIG.8. The manufacturing method in this embodiment is different in that the back portion forming step of the manufacturing method in the first embodiment is not present, and the front portion 4 and the back portion 5 are formed in the insert step, and the other steps are the first. This is the same as the manufacturing method in the embodiment.

  In the manufacturing method of this embodiment, the same foaming mold 8 as that of the manufacturing method of the first embodiment is used. The cavity formed in the mold 8 forms the fourth cavity 83 in the insert process and the injection process described below. Further, the fifth cavity 84 is formed after the foaming process. These cavity widths increase in the order of the fourth cavity 83 and the fifth cavity 84.

  As shown in FIG. 7, in the insert process in the embodiment, resin films having the same material and film thickness are respectively disposed on the mold surfaces of the second mold 82 and the first mold 81 that are separated from each other by a predetermined interval. . At this time, the fourth cavity 83 is formed in the mold 8 between the resin film disposed on the second mold surface 82a and the resin film disposed on the first mold surface 81a.

  Thereafter, an injection step of injecting the foamed resin material 61 into the fourth cavity 83, and a foaming step of increasing the volume of the fourth cavity 83 injected and filled with the foamed resin material 61 to form the fifth cavity 84 (FIG. 8). Are sequentially performed to form the molding intermediate 63. Then, the foaming resin molding 2 (FIG. 6) is shape | molded by cooling and solidifying the shaping | molding intermediate body 63 in a solidification process.

  Similarly to the foamed resin molded body 1 molded by the manufacturing method in the first embodiment, the foamed resin molded body 2 molded by the manufacturing method in the present embodiment is also a rough resin portion, and the front portion 4 and the resin film which is the back part 5 are dense resin parts. That is, since the foamed portion 6 having a large shrinkage rate is sandwiched from both sides with a resin film having a low shrinkage rate, warping due to a difference in shrinkage rate during molding can be effectively suppressed.

(Third embodiment)
The foamed resin molded body 3 of the third embodiment is different in the configuration of the foamed resin molded body 1 and the back portion 5 of the first embodiment. That is, in the foamed resin molded body 3 of the third embodiment, the back portion 5 and the foamed portion 6 are formed by foam molding, and the back portion 5 is formed of a resin portion that is denser than the foamed portion 6. Specifically, the back part 5 is a skin layer of the foamed resin body 30 described later.

  As shown in FIG. 9, the foamed resin molded body 3 of the third embodiment has a surface portion 4 that is a resin film and a foamed resin body 30. The foamed resin body 30 is formed by foaming a foamed resin material, and includes a first skin layer 31, a foam layer 33, and a second skin layer 32. In the foamed resin molded body 3 of this embodiment, in the foamed resin body 30, the second skin layer 32 becomes the back part 5, and the first skin layer 31 and the foamed layer 33 become the foamed part 6.

  The second skin layer 32 serving as the back portion 5 is formed so as to have a layer thickness larger than that of the first skin layer 31 at the time of molding. Therefore, the second skin layer 32 can be said to be a denser resin part than the first skin layer 31. That is, it can be said that the foamed portion 6 composed of the first skin layer 31 and the foamed layer 33 is a resin portion rougher than the resin film as the front portion 4 and the second skin layer 32 as the back portion 5.

  As shown in FIG. 9, the foamed resin body 30 of the foamed resin molded body 3 of the embodiment can be molded in a foaming process such as a core back that increases the cavity volume in the mold. The foamed resin body 30 includes a first skin layer 31 in contact with the resin film, a foam layer 33, and a second skin layer 32 located on the opposite side of the first skin layer 31 with the foam layer 33 interposed therebetween. That is, the foamed resin body 30 is laminated such that the foamed layer 33 is interposed between the first skin layer 31 and the second skin layer 32. The foam layer 33 is a resin part having a density lower than that of the first skin layer 31 and the second skin layer 32 and the first skin layer 31 and the second skin layer 32 are resin parts denser than the foam layer 33. .

  As shown in FIG. 9, in the foamed resin body 30, the layer thickness of the second skin layer 32 is larger than the layer thickness of the first skin layer 31 on the resin film side. That is, the foamed resin molded body 3 of this embodiment has a dense resin portion composed of the resin film and the first skin layer 31 on one side of the foam layer 33, and the first skin on the other side of the foam layer 33. It has a dense resin part composed of the second skin layer 32 having a larger layer thickness than the layer 31.

  The second skin layer 32 has a denser resin portion than the first skin layer 31 by increasing the thickness of the second skin layer 32 than the first skin layer 31. Then, the shrinkage rate of the second skin layer 32 at the time of molding can be made smaller than the shrinkage rate of the first skin layer 31. In addition, a resin film having a smaller shrinkage rate than the foam layer 33 is provided outside the first skin layer 31. That is, in the foamed resin molded body 3 of the embodiment, on one surface of the foamed portion 6 having the foam layer 33 having a large shrinkage rate at the time of molding, the front portion 4 that is a resin film having a small shrinkage rate at the time of molding, On the other side, the back portion 5 which is the second skin layer 32 having a small shrinkage rate at the time of molding is provided.

  As described above, the foamed resin molded body 3 includes the surface portion 4 that is a resin film made of a dense resin portion on both sides of the foamed portion 6 made of a coarse resin portion, and the second skin layer 32 made of a dense resin portion. Are sandwiched by the back portion 5. That is, also in the foamed resin molded body 3 of the embodiment, like the foamed resin molded body 3 of the first embodiment, the foamed portion 6 having a large shrinkage rate at the time of molding is replaced with the front portion 4 and the back portion having a small shrinkage rate. 5 can be said to be sandwiched from both sides, and the warpage caused by the difference in shrinkage during molding can be effectively suppressed.

  Making the layer thickness of the second skin layer 32 larger than the layer thickness of the first skin layer 31 can be performed by controlling the temperature of the mold surface to be described later. For example, by controlling the temperature of the mold surface on the first skin layer 31 side so that the temperature of the mold surface on the second skin layer 32 side is lower than the temperature of the surface of the resin film before the foaming step, The growth of the two skin layers 32 can be promoted. Thereby, the film thickness of the second skin layer 32 can be made larger than the film thickness of the first skin layer 31.

  The film thickness of the second skin layer 32 is preferably 1.5 to 3.5 times that of the first skin layer 31, and preferably 2.0 to 3.0 times. If the film thickness of the second skin layer 32 is within the above range, the shrinkage rate of the second skin layer 32 during molding can be sufficiently reduced.

  Moreover, it is desirable that the shrinkage rate between the resin film as the front portion 4 and the second skin layer 32 as the back portion 5 is as close as possible, and is preferably the same. Thus, at the time of molding, the resin film and the second skin layer 32 sandwiching the foamed portion 6 have shrinkage rates that are as close as possible to each other, so that it is possible to more effectively suppress warping caused by the difference in shrinkage rates. It becomes. Moreover, it becomes possible to suppress this curvature more effectively because the resin film and the second skin layer 32 sandwiching the foamed portion 6 have the same shrinkage rate.

  Next, the manufacturing method of the foamed resin molding 3 of 3rd Embodiment is demonstrated with reference to FIGS. The manufacturing method of the foamed resin molded body 3 according to the third embodiment is different from the manufacturing method according to the third embodiment in that there is no back portion forming step and that there is a temperature control step. This is the same as the manufacturing method in In the insert step of the manufacturing method in the embodiment, the front portion 4 that is a resin film is disposed on the second mold surface 92a.

  The manufacturing method in the embodiment includes an insert process, an injection process, a temperature control process, a foaming process, and a solidification process.

  In the manufacturing method in the embodiment, the same foaming mold 9 as that in the manufacturing method in the first embodiment is used. As shown in FIG. 10, the cavity formed in the mold 9 forms a sixth cavity 93 in the insert process and the injection process described below. Further, after the foaming process, a seventh cavity 94 is formed. These cavity widths increase in the order of the sixth cavity 93 and the seventh cavity 94.

  In the manufacturing method in the embodiment, a temperature control process for controlling the temperatures of the first mold surface 91a and the second mold surface 92a is performed together with the insert process and the injection process. That is, in the manufacturing method of the embodiment, the temperature of the first mold surface 91a and the second mold surface 92a is controlled before the foamed resin material 61 is injected into the mold 9 by the injection device.

  In the temperature control step, the thickness of the second skin layer 32 formed on the surface of the foamed resin material 61 opposite to the resin film side in the foamed resin material 61 injected and filled in the sixth cavity 93 is set to the first thickness. This is a process intended to be larger than one skin layer 31.

  In the temperature control step, the heating medium is supplied to the heating medium passage 92b provided in the second mold 92 to heat the second mold surface 92a, and the cooling medium is supplied to the cooling medium passage 91b provided in the first mold 91. To cool the first mold surface 91a. Specifically, as shown in FIG. 11, the foamed resin material 61 filled in the sixth cavity 93 is quickly put on the surface of the foamed resin material 61 opposite to the resin film side by the first mold surface 91 a. Cooling. Further, it is possible to prevent the surface of the foamed resin material 61 in contact with the resin film from being quickly cooled by the heated second mold surface 92a. That is, the surface of the foamed resin material 61 in contact with the resin film is slowly cooled. Thereby, the formation of the skin layer is promoted more in the second skin layer 32 formed by being cooled quickly than in the first skin layer 31 formed by being cooled slowly. That is, the layer thickness of the second skin layer 32 is larger than the layer thickness of the first skin layer 31. The first skin layer 31 is quickly cooled by the surface of the resin film heated by the second mold surface 92a.

  The first mold surface 91 a is cooled by the cooling medium before the foamed resin material 61 is injected into the sixth cavity 93. When the foamed resin material 61 is filled in the sixth cavity 93, the temperature of the first mold surface 91a is controlled to be 40 to 80 ° C., for example. Since the foamed resin material 61 filled in the sixth cavity 93 is melted by heating, the temperature is high (for example, about 140 ° C.). Therefore, if the temperature of the first mold surface 91a is within the above range, the surface of the foamed resin material 61 can be sufficiently cooled, which is effective in promoting the formation of the second skin layer 32.

  The second mold surface 92 a is also heated by the heating medium before the foamed resin material 61 is injected into the sixth cavity 93. The temperature of the 2nd type | mold surface 92a should just be the temperature which the resin film which is the surface part 4 does not fuse | melt, for example, the temperature control is 100-130 degreeC. If the temperature of the second mold surface 92a is within the above range, the surface of the foamed resin material 61 can be prevented from being quickly cooled via the resin film, and the thickness of the first skin layer 31 can be reduced to the second skin layer. It is effective to make it thinner than 32.

  The temperature control process may be performed at least before the injection process. In the temperature control process in the embodiment, the process is performed from before the foamed resin material 61 is injected into the mold 9 until the foaming process is completed. As described above, the second skin layer 32 can have a desired layer thickness by performing the temperature control process between the injection process and the foaming process.

  A heating medium and a cooling medium are not specifically limited, A well-known thing can be used. Examples of the heating medium include steam, pressurized hot water, and heating oil, and examples of the heating medium include an electric or electromagnetic induction heater as a heating means. Further, examples of the cooling medium include water, chlorofluorocarbon, liquid nitrogen, and the like.

  In the temperature control step, the growth of the second skin layer 32 is sufficiently promoted, and after forming the second skin layer 32 to a desired thickness, a foaming step is performed as shown in FIG. 64 is formed. Then, the foaming resin molding 3 of the said embodiment is shape | molded by performing the solidification process in which the shaping | molding intermediate body 64 is cooled and solidified.

  As described above, the foamed resin molded body 3 molded by the manufacturing method of the embodiment includes a resin film and a back portion in which both surfaces of the foamed portion 6 made of a rough resin portion are front portions 4 made of a dense resin portion. 5 is sandwiched between the second skin layers 32. That is, also in the foamed resin molded body 3 of the present embodiment, as with the foamed resin molded body 1 of the first embodiment, the foamed portion 6 having a large shrinkage rate at the time of molding is replaced with a resin film (surface portion 4) having a small shrinkage rate. ) And the second skin layer 32 (back portion 5), it is possible to effectively suppress the warpage caused by the difference in shrinkage rate during molding.

  As mentioned above, although the suitable embodiment of the foaming resin molding of the present invention and its manufacturing method has been explained, the foaming resin molding of the present invention and its manufacturing method are not particularly limited to the above-mentioned embodiment, and the following Even if it is such a modification, the effect of this invention can be show | played.

  For example, in the manufacturing method in the foamed resin molded body 2 of the second embodiment, after the solidification step, that is, after molding the foamed resin molded body 2 in which the front part 4 and the back part 5 are both resin films, the resin film of the back part 5 You may add the back part removal process which removes.

  Moreover, in the temperature control process of the manufacturing method in the foamed resin molded body 3 of the third embodiment, the second mold surface 92a is heated and the first mold surface 91a is cooled, but only the second mold surface 92a is used. The case where it heats may be sufficient and the case where only the 1st type | mold surface 91a is cooled may be sufficient. In short, the temperature of the first mold surface 91a and the second mold surface 92a is such that the surface of the foamed resin material on the resin film side is relatively higher in temperature than the surface of the foamed resin material on the opposite side. It only needs to be controlled.

  Moreover, the foamed resin molded body of the said embodiment is applicable to the various member in which weight reduction is desired. For example, the present invention can be applied to an interior member such as a door trim as well as an assembly member such as a bracket that is arranged on the back side of an instrument panel of an automobile and holds an air-conditioning register or a cluster.

The foamed resin molded article and the production method thereof of the present invention can be expressed as follows.
<1> A front part 4 made of a resin film, a back part 5, and a foam part 6 interposed between the front part 4 and the back part 5, and the front part 4 is inserted into the foam part 6. The foamed resin molded body is a foamed resin molded body in which the shrinkage rate of the front portion 4 and the back portion 5 is smaller than the shrinkage rate of the foamed portion 6 during foam molding of the foamed portion 6.
<2> A front portion 4 made of a resin film, a back portion 5, and a foamed portion 6 interposed between the front portion 4 and the back portion 5, and the front portion with respect to the back portion 5 and the foamed portion 6. 4 is a foamed resin molded body in which the front part 4 and the back part 5 are resin parts denser than the foamed part 6.
<3> The foamed resin molded article according to claim 1 or 2, wherein the shrinkage ratio between the front portion 4 and the back portion 5 is the same.
<4> The foamed resin molded body according to any one of claims 1 to 3, wherein the back portion 5 and the foamed portion 6 are two-color molded of the same material or different materials.
<5> The back resin part 5 is a foamed resin molded article according to any one of claims 1 to 3, which is made of a resin film inserted into the foam part 6.
<6> The foamed resin molding according to any one of claims 1 to 3, wherein the back part 5 and the foamed part 6 are formed by foam molding, and the back part 5 is formed of a skin layer that is a resin part denser than the foamed part 6. body.
<7> The method for producing the foamed resin molded body 1 according to claim 3 or 4, wherein a first mold 71 having a first mold surface 71a and a second mold surface 72a facing the first mold surface 71a are provided. A foam molding die 7 having a second mold 72 is used, and a resin material is injected into the first cavity 73 defined between the first mold surface 71a and the second mold surface 72a to form the back portion 5. Between the front portion 4 and the back portion 5, the insert step of disposing the front portion 4 on the first mold surface 71 a while the back portion 5 is disposed on the second mold surface 72 a An injection step of injecting the foamed resin material 61 into the second cavity 74 divided into two, a foaming step of foaming the foamed resin material 61 in the second cavity 74 to form a molding intermediate 62, and a molding intermediate 62 A method for producing a foamed resin molded body 1 comprising a solidifying step for solidifying.
<8> The method for producing a foamed resin molded body 2 according to claim 3 or 5, wherein a first mold 81 having a first mold surface 81a and a second mold surface 82a facing the first mold surface 81a are provided. An insert process in which the front mold 4 is disposed on one of the first mold surface 81a and the second mold surface 82a and the back 5 is disposed on the other. An injection step of injecting the foamed resin material 61 into the fourth cavity 83 defined between the portion 4 and the back portion 5, and foaming the foamed resin material 61 in the fourth cavity 83 to form a molding intermediate 63. The manufacturing method of the foaming resin molding 2 including a foaming process and the solidification process which solidifies the shaping | molding intermediate body 63. FIG.
<9> The method for manufacturing the foamed resin molded body 3 according to claim 6, wherein the first mold 91 having the first mold surface 91a and the second mold surface 92a facing the first mold surface 91a are provided. Using the foaming mold 9 having two molds 92, an insert step of disposing the front part 4 on one of the first mold surface 91a and the second mold surface 92a, the surface of the front part 4, and the first mold surface 91a And the injection step of injecting the foamed resin material 61 into the sixth cavity 93 defined between the second mold surface 92a and the other of the second mold surface 92a, and the temperature of the other of the first mold surface 91a and the second mold surface 92a A temperature control step of relatively lowering the temperature of the step, a foaming step of foaming the foamed resin material 61 in the sixth cavity 93 to form a molding intermediate 64, and a solidification step of solidifying the molding intermediate 64. The manufacturing method of the foaming resin molding 3 containing.

1, 2, 3: Foamed resin molding 4: Front part 5: Back part 6: Foaming part 61: Foaming resin material 62, 63, 64: Molding intermediates 7, 8, 9: Foaming mold (molding mold)
71, 81, 91: 1st type | mold 71a, 81a, 91a: 1st type | mold surface 72, 82, 92: 2nd type | mold 72a, 82a, 92a: 2nd type | mold surface 73: 1st cavity 74: 2nd cavity 83: Fourth cavity 93: Sixth cavity

Claims (9)

A foamed resin molded article comprising a front part made of a resin film, a back part, and a foamed part interposed between the front part and the back part, wherein the front part is inserted into the foamed part. There,
At the time of foam molding of the foamed part, the shrinkage rate of the front part and the back part is a foamed resin molded body that is smaller than the shrinkage rate of the foamed part. Foam in which a front part made of a resin film, a back part, and a foamed part interposed between the front part and the back part are provided, and the front part is inserted into the back part and the foamed part A resin molded body,
The said back part is a foaming resin molding which is a resin part denser than the said foaming part.   The foamed resin molded product according to claim 1 or 2, wherein the shrinkage rate of the front portion and the back portion is the same.   The foamed resin molded body according to any one of claims 1 to 3, wherein the back portion and the foamed portion are two-color molded of the same material or different materials.   The said back part is a foamed resin molding as described in any one of Claims 1-3 which consists of a resin film inserted with respect to the said foaming part.   The foamed resin molded article according to any one of claims 1 to 3, wherein the back part and the foamed part are formed by foam molding, and the back part is a skin layer that is a resin part denser than the foamed part. A method for producing a foamed resin molded article according to claim 3 or 4,
Using a foam mold having a first mold having a first mold surface and a second mold having a second mold surface facing the first mold surface,
A back portion forming step of injecting a resin material into a first cavity defined between the first mold surface and the second mold surface to form the back portion;
An insert step of disposing the front portion on the first mold surface while the back portion is disposed on the second mold surface;
An injection step of injecting a foamed resin material into a second cavity defined between the front portion and the back portion;
A foaming step of foaming the foamed resin material in the second cavity to form a molding intermediate;
A solidification step of solidifying the molding intermediate;
The manufacturing method of the foaming resin molding containing this. It is a manufacturing method of the foaming resin fabrication object according to claim 3 or 5,
Using a foam mold having a first mold having a first mold surface and a second mold having a second mold surface facing the first mold surface,
An insert step of disposing the front portion on one of the first mold surface and the second mold surface and disposing the back portion on the other;
An injection step of injecting a foamed resin material into a fourth cavity defined between the front portion and the back portion;
A foaming step of foaming the foamed resin material in the fourth cavity to form a molding intermediate;
A solidification step of solidifying the molding intermediate;
The manufacturing method of the foaming resin molding containing this. It is a manufacturing method of the foaming resin fabrication object according to claim 6,
Using a foam mold having a first mold having a first mold surface and a second mold having a second mold surface facing the first mold surface,
An insert step of disposing the front portion on one of the first mold surface and the second mold surface;
An injection step of injecting a foamed resin material into a sixth cavity defined between the surface of the front portion and the other of the first mold surface and the second mold surface;
In the first mold surface and the second mold surface, a temperature control step of making the other temperature relatively lower than the one temperature;
A foaming step of foaming the foamed resin material in the sixth cavity to form a molding intermediate;
A solidification step of solidifying the molding intermediate;
The manufacturing method of the foaming resin molding containing this.

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