JP6940747B2 - Manufacturing method of integrally molded body and integrally molded body - Google Patents

Description

The present invention relates to an integrally molded body and a method for producing the same.

Some automobile interior members such as door trims may require attachment of insert members such as clips to a resin molded body (base material) made of thermoplastic resin for the purpose of assembling with other parts. .. In such a case, by introducing the resin into the cavity with the insert member arranged in the cavity of the mold, an integrally molded body composed of the base material and the insert member is formed. In Patent Document 1, one foamed resin sheet is reheated to be in a softened state and placed between a pair of split molds, and the foamed resin sheet is sucked under reduced pressure from both molds to obtain a foamed resin. A technique for forming a thick portion in a foamed molded product by secondary foaming a sheet is disclosed.

Japanese Unexamined Patent Publication No. 2001-310380

As described above, the integrally molded body used as an automobile interior member is required to have a high degree of designability in terms of appearance (design surface) visually recognized by the consumer. For example, if the integrally molded body is a double-walled body, the uneven shape derived from the insert member does not occur on the design surface side, but in the case of a single-walled body, the uneven shape appears on the design surface side and the design property is deteriorated. It is expected to be done. As a workaround, the product thickness may be increased to a level at which the uneven shape does not appear, but the product weight may increase and the practicality as a product may be impaired.

The present invention has been made in view of such circumstances, and provides an integrally molded body capable of avoiding exposure of an uneven shape by an insert member and a method for manufacturing the same.

According to the first aspect of the present invention, the foam molded product in the form of a sheet and an insert member are provided, the foamed molded product has first and second surfaces facing each other, and the insert member is a main body portion. An integrally molded body comprising, and an extending portion extending from the main body portion, and the extending portion is embedded inside the foam molded body on the first surface side. Is provided.

In the integrally molded body according to the first aspect of the present invention, the base material is made of foamed resin, is lightweight, and the insert member is embedded in the base material to be molded. It is possible to avoid the exposure of the uneven shape derived from the insert member. That is, it is possible to mold an integrally molded body having higher practicality and design.

In the present invention, a foamed resin is used instead of a solid resin as the base material. In a solid single-walled body, it is necessary to increase the thickness of the base material in order to hide the unevenness, but when a foamed resin is used, it is easier to make a product that is lighter than a non-foamed molded product. Moreover, since it is a foamed resin, it can be thickened by vacuum shaping. At this time, when the insert molding is performed only by increasing the internal bubble diameter, it is almost unnecessary to change the product weight even if the product thickness is increased to a level where the uneven shape does not appear.

Further, since it is a foamed resin as compared with the conventional solid resin, it is expected that the pull-out strength of the insert member will be lowered. Therefore, by compressing the periphery of the portion where the insert member is arranged, the pull-out strength can be increased by improving the circumference of the resin around the insert member.

As described above, according to the present invention, the uneven shape of the insert member mounting portion is not shown on the design surface side, the weight is light even when the thickness of the base material is large, and the insert member is pulled out by compressing the peripheral portion. It has high strength and can produce a highly designed foam molded product.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with each other.
Preferably, the second surface has a flat region corresponding to the insert member and a region around the insert member.
Preferably, the foam molded product comprises first and second portions, in which the insert member is embedded and t1> t2, where t1 is the thickness of the first portion. Yes, the t2 is the wall thickness of the second portion.
Preferably, a groove is provided at the boundary between the first portion and the second portion.
Preferably, the second surface is covered with a skin member.
Preferably, the average wall thickness of the foam molded product is 20 mm or less.

Further, according to the second aspect of the present invention, it is a method of manufacturing an integrally molded body using the first and second dies, which includes an insert step, an arrangement step, and a molding step. In the insert step, the insert member is mounted on the second mold, and in the placement step, the mold is mounted between the first and second molds with the insert member mounted on the second mold. The foamed resin in a molten state is hung down, and the insert member includes a main body portion and an extending portion extending from the main body portion, and the extending portion is embedded in the foamed resin in the molding process. The method is provided.

From the second aspect of the present invention, by sucking the foamed resin sheet in a molten state under reduced pressure by both the first and second molds, air bubbles in the central portion, which are less likely to be cooled by the atmosphere and have a low viscosity, are stretched and the mold is formed. It is possible to increase the wall thickness to the gap provided between them. Therefore, when the insert member is inserted, the uneven shape is less likely to appear on the design surface side, and a flat molded body having high designability can be manufactured.

Preferably, the molding step includes an expansion step, and the expansion step includes the first and second molds so that a gap larger than the thickness of the foamed resin is provided between the first and second molds. The foamed resin is expanded to the thickness of the gap by sucking the foamed resin under reduced pressure with both the first and second molds in a state where the molds are brought close to each other.
Preferably, the expansion step includes a first suction step, a mold proximity step, and a second suction step in this order, and in the first suction step, the foamed resin is sucked under reduced pressure by the first mold. The foamed resin is shaped into a shape along the cavity of the first mold, and in the mold proximity step, the first and first molds are provided so that the gap is provided between the first and second molds. The two molds are brought close to each other, and in the second suction step, the foamed resin is sucked under reduced pressure by the first and second molds to expand the foamed resin to the thickness of the gap.
Preferably, the second mold includes a convex portion that surrounds the mounting portion of the insert member, and in the expansion step, the convex portion presses the foamed resin to form a groove in the foamed resin.

It is a perspective view of the integrally molded body 1 according to the embodiment of the present invention, in particular, FIG. 1A shows the first surface 3a side, and FIG. 1B shows the second surface 3b side. It is an exploded view which disassembled the integrally molded body 1 shown in FIG. 1 into an insert member 2 and a foam molded body 3. 3A is a plan view of the integrally molded body 1 shown in FIG. 1, FIG. 3B is a sectional view taken along line PP of FIG. 3A, and FIG. 3C is a partially enlarged view of FIG. 3B. It is a perspective view of the integrally molded body 1 which concerns on the modification which does not provide the 1st part 1st surface 3ca and the groove 3e shown in FIG. 2 and the like. An example of a foam molding machine that can be used in the method for manufacturing the integrally molded body 1 according to the embodiment of the present invention is shown. It is a perspective view of the 1st and 2nd molds 21 and 22. Here, the decompression suction holes 21a and 22a are not shown in consideration of visibility. It is a perspective view seen from the angle different from FIG. It is an end view which shows the Q cross section of FIG. 7 about 1st and 2nd molds 21 and 22. FIG. 5 is an end view showing a state in which the insert member 2 is arranged and the foamed resin sheet 23 is hung down, continuing from the state of FIG. FIG. 5 is an end view showing a state in which decompression suction is performed through the decompression suction hole 21a, continuing from the state of FIG. FIG. 5 is an end view showing a state in which decompression suction is performed through the decompression suction hole 21a, continuing from the state of FIG. FIG. 5 is an end view showing a state in which the foamed resin sheet 23 is expanded to the thickness of the gap G by performing decompression suction through the decompression suction hole 22a, continuing from the state of FIG. A cross-sectional photograph of the foam molded product 3 obtained in the examples of the present invention is shown. An example of the form of bubbles for explaining the calculation method of the tentative average bubble diameter is shown.

Hereinafter, embodiments of the present invention will be described. The various features shown in the embodiments shown below can be combined with each other. In addition, the invention is independently established for each feature.

1. 1. Integral molded body 1
1A and 1B are perspective views showing an integrally molded body 1 according to an embodiment of the present invention. As shown in FIGS. 1A and 1B, the integrally molded body 1 according to the embodiment of the present invention is an automobile interior member such as a door trim, and is an integrally molded body formed by insert molding. That is, the integrally molded body 1 includes an insert member 2 (for example, a clip) molded by injection molding or the like, and a foam molded body 3 molded so that the insert member 2 is embedded. As shown in FIGS. 1A and 1B, the foam molded product 3 has a sheet-like shape and has a first surface 3a and a second surface 3b. Here, the first surface 3a is a surface on which the insert member 2 is attached, and the second surface 3b is the back surface (so-called design surface) thereof, and is a region corresponding to the insert member 2 (that is, facing the second surface 3b). A region in which the insert member 2 is embedded in the first surface 3a) and a region around the insert member 2) are flat. Although not shown in FIGS. 1A and 1B, the second surface 3b may be covered with a skin member such as a carpet. In the method for manufacturing the integrally molded body 1 described later, the case where the integrally molded body 1 is covered with a skin member will be described.

FIG. 2 is an exploded view of the integrally molded body 1 shown in FIG. 1A decomposed into an insert member 2 and a foam molded body 3. 3A is a plan view of the integrally molded body 1 shown in FIGS. 1A and 1B, FIG. 3B is a sectional view taken along line PP of FIG. 3A, and FIG. 3C is a partially enlarged view of FIG. 3B. Is. The insert member 2 may be a resin molded body or a metal molded body, and the manufacturing method thereof is not particularly limited. As shown in FIG. 2, the insert member 2 includes a main body portion 2a and an extension portion 2b. In particular, as shown in FIGS. 3B and 3C, the main body portion 2a is adjacent to the embedded portion 2aa embedded in the foam molded body 3 via the first surface 3a and the embedded portion 2aa in the integrally molded body 1. Moreover, it is provided with a protruding portion 2ab that is not embedded in the foam molded body 3 and protrudes from the first surface 3a. The extending portion 2b is adjacent to the embedding portion 2aa on the second surface 3b side of the embedding portion 2aa. The extending portion 2b extends in the plane direction related to the first and second surfaces 3a and 3b. With such a configuration, the insert member 2 is prevented from coming out of the foam molded body 3. In the present embodiment, as shown in FIG. 3A and the like, the shape of the extending portion 2b in a plan view is substantially square, but this may be a substantially rectangular shape or a substantially circular shape.

The foam molded product 3 has first and second surfaces 3a and 3b as described above. Further, the foam molded body 3 has a first portion 3c and a second portion 3d, which are two portions having different wall thicknesses, and the first surface 3a with respect to the two portions is the first portion first surface 3ca and the first portion. The second part is referred to as the first surface 3da. The insert member 2 is arranged so as to be embedded in the first portion first surface 3ca. As shown in FIG. 3C, where t1 is the wall thickness of the first portion 3c and t2 is the wall thickness of the second portion 3d, t1> t2. The values of t1 / t2 are, for example, 1.1 to 3.0, and specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1. 7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, It is 3.0, and may be within the range between any two of the numerical values exemplified here.

As shown in FIG. 3C, where the wall thickness of the extending portion 2b is t3, the value of t3 / t1 is, for example, 0.05 to 0.90, and specifically, for example, 0.05, 0. .10, 0.15, 0.25, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70 , 0.75, 0.80, 0.85, 0.90, and may be within the range between any two of the numerical values exemplified here.

As shown in FIG. 3C, where h is the height of the embedded portion 2aa (that is, the depth at which the extending portion 2b is buried from the first surface 3ca of the first portion), the value of h / t1 is, for example, It is 0.05 to 0.80, and specifically, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0. It is 45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, even if it is within the range between any two of the numerical values exemplified here. good.

As shown in FIGS. 3B and 3C, a groove 3e is provided at the boundary between the first portion first surface 3ca and the second portion first surface 3da. As shown in FIG. 3C, where d is the depth of the groove, the value of d / t2 is, for example, 0.05 to 0.90, and specifically, for example, 0.05, 0.10, 0. .15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75 , 0.80, 0.85, 0.90, and may be within the range between any two of the numerical values exemplified here. That is, the first portion 3c and the second portion 3d are defined with the groove 3e separated from each other. In the present embodiment, as shown in FIG. 3A and the like, the first portion first surface 3ca has a substantially square shape, but the groove so that the first portion first surface 3ca has a substantially rectangular shape or a substantially circular shape. 3e may be formed. Further, it should be noted that it is only necessary to prevent the insert member 2 from falling out of the foam molded body 3, and the first portion first surface 3ca and the groove 3e are not essential configurations (see FIG. 4).

Further, as shown in FIG. 3C, the length of one side of the first portion first surface 3ca in the plane direction is L1, the length of one side of the extending portion 2b in the same direction is L3, and the width of the groove 3e is defined as the width of the groove 3e. When w, the value of L3 / L1 is, for example, 0.30 to 0.80, and specifically, for example, 0.30, 0.35, 0.40, 0.45, 0.50, 0. It is 55, 0.60, 0.65, 0.70, 0.75, 0.80, and may be within the range between any two of the numerical values exemplified here. The value of w / L1 is, for example, 0.01 to 0.30, and specifically, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0. .07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 , 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, which are exemplified here. It may be within the range between any two of the given numerical values.

The average wall thickness of the foam molded product 3 in consideration of all the first and second portions 3c and 3d and the groove 3e is preferably 20 mm or less. This average wall thickness is, for example, 1 to 20 mm, and specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16. , 17, 18, 19, 20 mm, and may be within the range between any two of the numerical values exemplified here.

2. Configuration of Foam Molding Machine 4 Subsequently, with reference to FIGS. 5 to 12, a foam molding machine that can be used to carry out the method for producing an integrally molded body according to an embodiment of the present invention will be described. FIG. 5 shows an example of a foam molding machine that can be used in the method for manufacturing the integrally molded body 1 according to the embodiment of the present invention. The foam molding machine 4 includes a resin supply device 5, a T-die 18, a first mold 21, and a second mold 22. The resin supply device 5 includes a hopper 12, an extruder 13, an injector 16, and an accumulator 17. The extruder 13 and the accumulator 17 are connected via a connecting pipe 25. The accumulator 17 and the T-die 18 are connected via a connecting pipe 27. The T-die can also be carried out by using a cylindrical die core. Hereinafter, each configuration will be described in detail.

<Hopper 12, extruder 13>
The hopper 12 is used to put the raw material resin 11 into the cylinder 13a of the extruder 13. The form of the raw material resin 11 is not particularly limited, but is usually in the form of pellets. The raw material resin is, for example, a thermoplastic resin such as polyolefin, and examples of the polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer and a mixture thereof. The raw material resin 11 is charged into the cylinder 13a from the hopper 12 and then melted by being heated in the cylinder 13a to become a molten resin. Further, it is conveyed toward the tip of the cylinder 13a by the rotation of the screw arranged in the cylinder 13a. The screw is arranged in the cylinder 13a, and the molten resin is kneaded and conveyed by its rotation. A gear device is provided at the base end of the screw, and the screw is rotationally driven by the gear device. The number of screws arranged in the cylinder 13a may be one or two or more.

<Injector 16>
The cylinder 13a is provided with an injector 16 for injecting a foaming agent into the cylinder 13a. Examples of the foaming agent injected from the injector 16 include a physical foaming agent, a chemical foaming agent, and a mixture thereof, and a physical foaming agent is preferable. As the physical foaming agent, inorganic physical foaming agents such as air, carbon dioxide, nitrogen gas, and water, organic physical foaming agents such as butane, pentane, hexane, dichloromethane, and dichloroethane, and their supercritical fluids are used. be able to. As the supercritical fluid, it is preferable to use carbon dioxide, nitrogen, etc., for nitrogen, the critical temperature is -149.1 ° C, the critical pressure is 3.4 MPa or more, and for carbon dioxide, the critical temperature is 31 ° C, the critical pressure. It is obtained by setting the pressure to 7.4 MPa or more. Examples of the chemical foaming agent include those that generate carbon dioxide gas by a chemical reaction between an acid (eg, citric acid or a salt thereof) and a base (eg, baking soda). The chemical foaming agent may be injected from the hopper 12 instead of being injected from the injector 16.

<Accumulator 17, T-die 18>
The foamed resin obtained by melt-kneading the raw material resin and the foaming agent is extruded from the resin extrusion port of the cylinder 13a and injected into the accumulator 17 through the connecting pipe 25. The accumulator 17 includes a cylinder 17a and a piston 17b slidable inside the cylinder 17a, so that foamed resin can be stored in the cylinder 17a. Then, by moving the piston 17b after a predetermined amount of the foamed resin is stored in the cylinder 17a, the foamed resin is pushed out from the slit provided in the T die 18 through the connecting pipe 27 and hung down to form the foamed resin sheet 23. Form.

<Molds 21 and 22>
6 and 7 are perspective views of the first and second molds 21 and 22. Here, the decompression suction holes 21a and 22a are not shown in consideration of visibility. The foamed resin sheet 23 (see FIG. 9) is guided between the first mold 21 and the second mold 22 (both are collectively referred to as molds 21 and 22). As shown in FIGS. 8 to 12, the first mold 21 is provided with a large number of decompression suction holes 21a, and the foamed resin sheet 23 is decompressed and sucked along the cavity 21b of the first mold 21. It is possible to shape it into a plastic shape. Further, as shown in FIGS. 6 and 8 to 12, a pinch-off portion 21d is provided so as to surround the cavity 21b. As shown in FIGS. 8 to 12, the second mold 22 is provided with a large number of decompression suction holes 22a, and the foamed resin sheet 23 is decompressed and sucked along the cavity 22b of the second mold 22. It is possible to shape it into a plastic shape. As shown in FIGS. 7 to 12, a pinch-off portion 22d is provided so as to surround the cavity 22b.

In the present embodiment, the second mold 22 is provided with an insert member arranging portion 22e into which the insert member 2 can be inserted. Here, as an example, it is assumed that there is only one insert member arranging location 22e, but a plurality of insert member arranging locations 22e may be provided so that a plurality of insert member 2 can be arranged. It should be noted here that the insert member 2 is arranged above the center of the second mold 22. Generally, the resin temperature tends to be higher on the upper side of the mold than on the lower side. That is, with such an arrangement, the meat circumference when embedding the insert member 2 in the foam molded body 3 is improved. Further, as a result, the pull-out strength of the insert member 2 becomes stronger. Further, a convex portion 22f is provided around the insert member arranging portion 22e in the second mold 22. The foamed resin around the insert member 2 is compressed by the convex portion 22f when the molds 21 and 22 are clamped, which will be described in detail later.

3. 3. Method for manufacturing integrally molded body 1 Here, a method for manufacturing the integrally molded body 1 according to the embodiment of the present invention will be described with reference to FIGS. 8 to 12. The method of this embodiment includes an insert step, a placement step, and an expansion step. Hereinafter, a detailed description will be given.

3.1 Insert step In this step, in the molds 21 and 22 in the open state shown in FIG. 8, the preformed insert member 2 is placed at the insert member placement portion 22e in the second mold 22. (Fig. 9). Here, it is assumed that the skin member 6 is hung between the molds 21 and 22 in advance. The method of inserting into the second mold 22 may be a method of using a robot or the like, in addition to a method of mounting by a human hand.

3.2 Arrangement step In this step, as shown in FIG. 9, one foamed resin sheet 23 formed by extruding the molten foam resin from the slit of the T die 18 and hanging it is placed between the molds 21 and 22. Therefore, it is arranged closer to the mold 22 than the skin member 6. That is, the skin member 6, the foamed resin sheet 23, and the insert member 2 are arranged in this order from the mold 21 to the mold 22. In the present embodiment, since the direct vacuum forming using the foamed resin sheet 23 extruded from the T die 18 as it is is performed, the foamed resin sheet 23 is not cooled to room temperature and solidified before molding. The solidified foamed resin sheet 23 is not heated before molding. Further, the foamed resin sheet 23 of the present embodiment has a substantially uniform temperature as a whole immediately after being extruded from the slit, and is gradually cooled from the surface by the atmosphere while being hung down. The foamed resin sheet 23 of the present embodiment is less affected by cooling by the atmosphere toward the center in the thickness direction of the foamed resin sheet 23. Therefore, the temperature of the foamed resin sheet 23 of the present embodiment rises toward the center in the thickness direction to increase the viscosity. Has the property of becoming low. The wall thickness of the foamed resin sheet 23 is not particularly limited, but is, for example, 0.5 to 5.0 mm, preferably 1.0 to 3.0 mm. Specifically, the wall thickness is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mm. It may be within the range between any two of the numerical values exemplified here.

3.3 Expansion step In this step, as shown in FIGS. 10 to 12, the molds 21 and 22 are provided so that a gap G larger than the thickness of the foamed resin sheet 23 is provided between the molds 21 and 22. The foamed resin sheet 23 is sucked under reduced pressure from both the molds 21 and 22 in a close state. As a result, the foamed resin sheet 23 is expanded to the thickness of the gap G. At this time, the convex portion 22f locally presses the foamed resin sheet 23, so that the portion is compressed. The portion corresponds to the groove 3e in the foam molded body 3. By such compression, the foamed resin effectively wraps around the extending portion 2b of the insert member 2 arranged in the second mold 22, and the insert member 2 is prevented from being detached. As a result of such molding, since the first portion 3c is molded to be thicker than the second portion 3d, the insert member 2 does not protrude to the second surface 3b side. In other words, the second surface 3b has a flat region corresponding to the insert member 2 (that is, a region of the second surface 3b in which the insert member 2 is embedded in the opposite first surface 3a) and a region around the second surface 3b. It will be molded so as to become. Further, as shown in FIGS. 10 to 12, in this step, the skin member 6 and the foamed resin sheet 23 are integrated on the side of the mold 21. The expansion step is not essential, and for example, the foamed resin sheet 23 may be crushed by the first and second dies 21 and 22 to be molded so as to embed the insert member 2. In particular, a cylindrical foamed parison may be used instead of the foamed resin sheet 23.

In the present embodiment, the molds 21 and 22 are provided with pinch-off portions 21d and 22d, and when the molds 21 and 22 are brought close to each other until the pinch-off portions 21d and 22d come into contact with each other, a space surrounded by the pinch-off portions 21d and 22d. Is the closed space S. The portion of the foamed resin sheet 23 in the closed space S becomes the foamed molded product 3. On the other hand, the portion of the foamed resin sheet 23 outside the closed space S becomes the burr 3f.

The cavities 21b and 22b of the molds 21 and 22 are located between the molds 21 and 22 over the entire portion of the foamed resin sheet 23 that becomes the foamed molded product 3 (that is, the portion in the closed space S). The gap G is configured to be substantially constant. When the foamed resin sheet 23 is sucked under reduced pressure by the molds 21 and 22 in this state, the foamed resin sheet 23 expands to the thickness of the gap G to form the foamed molded product 3. The pinch-off portions 21d and 22d are not indispensable, and the molds 21 and 22 may be brought close to each other in a non-contact manner so that a gap G is formed between the molds 21 and 22. However, if decompression suction is performed by the molds 21 and 22 in a state where the pinch-off portions 21d and 22d are brought into contact with each other to form the closed space S, the pressure in the closed space S tends to decrease, so that the foamed resin sheet 23 is expanded. It has the advantage of being easy.

The thickness of the gap G is not particularly limited, but is preferably 1.1 to 3.0 times the thickness of the foamed resin sheet 23. Specifically, (thickness of gap G) / (thickness of foamed resin sheet 23) is, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1 .7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 , 3.0, and may be within the range between any two of the numerical values exemplified here.

In the decompression suction by the molds 21 and 22, the decompression suction by the first mold 21 may be started first, or the decompression suction by the second mold 22 may be started first, and the decompression suction by the molds 21 and 22 may be started first. Decompression suction may be started at the same time. Further, the decompression suction by the first mold 21 may be stopped first, the decompression suction by the second mold 22 may be stopped first, or the decompression suction by the molds 21 and 22 may be stopped at the same time. good. The decompression suction by the molds 21 and 22 may be started before the molds 21 and 22 are brought close to each other, or may be started after the molds 21 and 22 are brought close to each other.

When the foamed resin sheet 23 is sucked under reduced pressure by both the molds 21 and 22, the foaming of the foamed resin sheet 23 is promoted and the foamed resin sheet 23 expands. Since the foamed resin sheet 23 has the lowest viscosity (highest fluidity) near the center in the thickness direction, foaming near the center in the thickness direction is particularly promoted and the foamed resin sheet 23 expands. As a result, the foamed molded product 3 having a structure in which the average cell diameter in the layer near the center (central layer) in the thickness direction is large and the average cell diameter in the surface layer near the surface is small can be obtained. Such a foamed molded body 3 is lightweight and highly rigid because the central layer having a large average cell diameter has a sandwich structure sandwiched between surface layers having a small average cell diameter.

As shown in the cross-sectional photograph of FIG. 13, the foamed molded body 3 obtained by the method of the present embodiment has a layer from the surface of the foamed molded body 3 to a thickness of 10% with respect to the wall thickness of the foamed molded body 3. Is used as the surface layer, and a layer having a thickness of 25 to 50% from the surface of the foamed molded product is used as the central layer, the average cell diameter of the central layer becomes larger than the average cell diameter of the surface layer. The ratio of (average cell diameter of the central layer) / (average cell diameter of the surface layer) is not particularly limited, but is, for example, 1.2 to 10. Specifically, this ratio is, for example, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 7.0, 8.0, 9.0, 10.0, which are exemplified here. It may be in the range between any two of the numerical values.

The average cell diameter of the entire foam molded product 3 in the thickness direction is, for example, 100 to 2000 μm. Specifically, the average bubble diameter is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000 μm, and is between any two of the numerical values exemplified here. It may be within the range. The average cell diameter of the surface layer is, for example, 80 to 500 μm. Specifically, the average bubble diameter is, for example, 80, 100, 150, 200, 250, 300, 350, 400, 450, 500 μm, and is within the range between any two of the numerical values exemplified here. You may. The average bubble diameter of the central layer is, for example, 100 to 2000 μm. Specifically, the average cell diameter is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900. It is 2000 μm and may be within the range between any two of the numerical values exemplified here.

The average cell diameter is measured by the following method.
First, a cross-sectional photograph of the foam molded product 3 is taken at a magnification of 50 times as shown in FIG.
-Next, in the cross-sectional photograph, five reference lines R1 to R5 extending in the thickness direction are drawn. The distance between the reference lines is 500 μm.
-For each reference line, count the number of bubbles passing through the reference line in the layer to be measured (surface layer, central layer, or the entire thickness direction).
-Measure the maximum length in the thickness direction (the length at the part where the length in the thickness direction is the longest) for each bubble.
-Calculate the tentative average bubble diameter for each reference line according to Equation 1. Further, the average cell diameter is calculated by arithmetically averaging the tentative average cell diameters calculated for each reference line.
(Equation 1) Temporary average bubble diameter = total maximum length of all counted bubbles / number of counted bubbles

For example, in the example of FIG. 14, the number of bubbles through which the reference line R passes in the central layer is 6, and the maximum length of each bubble in the thickness direction is l1 to l6. Therefore, in this example, the tentative average bubble diameter of the central layer is calculated by (l1 + l2 + l3 + l4 + l5 + l6) / 6.

The expansion step is preferably performed by executing the first suction step, the mold proximity step, and the second suction step in this order. In the first suction step, as shown in FIG. 10, the foamed resin sheet 23 is sucked under reduced pressure by the first mold 21 to shape the foamed resin sheet 23 into a shape along the cavity 21b of the first mold 21. .. In the mold proximity step, as shown in FIG. 11, the molds 21 and 22 are brought close to each other so that the gap G is provided between the molds 21 and 22. In the second suction step, as shown in FIG. 12, the foamed resin sheet 23 is sucked under reduced pressure by the molds 21 and 22, and the foamed resin sheet 23 is expanded to the thickness of the gap G.

If decompression suction by the molds 21 and 22 is started after the molds 21 and 22 are brought close to each other, the foamed resin sheet 23 comes into contact with the convex portion 22c of the mold 22 before the foamed resin sheet 23 is formed. .. Normally, the temperatures of the molds 21 and 22 are lower than the temperature of the foamed resin sheet 23. Therefore, when the foamed resin sheet 23 comes into contact with the convex portion 22c of the mold 22, the foamed resin sheet 23 is cooled and its viscosity increases. However, the followability of the molds 21 and 22 to the cavities 21b and 22b deteriorates. On the other hand, when the expansion step is performed by executing the first suction step, the mold proximity step, and the second suction step in this order, the foamed resin sheet 23 has a shape along the cavity 21b of the first mold 21. Since the contact of the foamed resin sheet 23 with the molds 21 and 22 before being shaped is minimized, the increase in the viscosity of the foamed resin sheet 23 is suppressed, and the foamed resin sheet 23 is pressed into the mold 21. , 22 cavities can be made to follow with high accuracy.

3.4 Finishing step After the expansion step, the molds 21 and 22 are opened, the foamed molded product 3 with the burr 3f is taken out, and the foamed molded product 3 is obtained by cutting the burr 3f. The insert member 2 is embedded in the foam molded body 3, that is, a desired integrally molded body 1 can be obtained.

4. Conclusion According to the integrally molded body 1 according to the present embodiment, the following effects can be obtained.
(1) Since foamed resin is used as a raw material for the base material, it is possible to produce a product that is lighter than the unfoamed molded product. Further, since it is a foamed resin, it can be thickened by vacuum shaping as described above. At this time, only the diameter of the internal bubbles is increased, and even if the product thickness is increased to a level at which the uneven shape does not appear when performing insert molding, there is almost no need to change the product weight.
(2) Since it is a foamed resin as compared with the conventional solid resin, it is expected that the pull-out strength of the insert member will decrease. Therefore, by compressing the periphery where the insert member 2 is embedded (compression portion 23e, groove 3e), it is possible to improve the circumference of the resin to the insert member 2 and increase the pull-out strength.

As described above, according to the present embodiment, when the uneven shape of the mounting portion of the insert member 2 is not shown on the second surface 3b (design surface) side and the wall thickness of the foam molded body 3 (base material) is large. However, it is possible to manufacture an integrally molded body 1 having high practicality and design, which is lightweight.

Although the embodiments according to the present invention have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1: Integral molded body 2: Insert member 2a: Main body part 2aa: Embedded part 2ab: Protruding part 2b: Extension part 3: Foam molded body 3a: First surface 3b: Second surface 3c: First part 3ca: First 1st part 1st surface 3d: 2nd part 3da: 2nd part 1st surface 3e: Groove 3f: Burr 4: Foam molding machine 5: Resin supply device 6: Skin member 11: Raw material resin 12: Hopper 13: Extruder 13a : Cylinder 16: Injector 17: Accumulator 17a: Cylinder 17b: Piston 18: T-die 21: First mold 21a: Decompression suction hole 21b: Cavity 21d: Pinch-off portion 22: Second mold 22a: Decompression suction hole 22b: Cavity 22c: Convex portion 22d: Pinch-off portion 22e: Insert member placement location 22f: Convex portion 23: Foamed resin sheet 25: Connecting pipe 27: Connecting pipe

Claims (9)

A sheet-shaped foam molded body and an insert member are provided.
The foam molded product has first and second surfaces facing each other, and has a first surface and a second surface facing each other.
The second surface is a design surface,
The insert member includes a main body portion and an extension portion extending from the main body portion.
The extending portion is embedded inside the foamed molded product on the first surface side so as to come into contact with the foamed molded product.
The main body portion protrudes toward the first surface side.
The foamed molded article includes first and second parts.
In the first part, the insert member is embedded and
t1> t2,
The t1 is the wall thickness of the first portion, and the t2 is the wall thickness of the second portion.
One body moldings. The second surface has a flat region corresponding to the insert member and a region around the insert member.
The integrally molded body according to claim 1. A groove is provided at the boundary between the first portion and the second portion.
The integrally molded body according to claim 1. The second surface is covered with a skin member.
The integrally molded body according to any one of claims 1 to 3. The average wall thickness of the foam molded product is 20 mm or less.
The integrally molded body according to any one of claims 1 to 4. A method for manufacturing an integrally molded body using the first and second dies.
The method includes an insert step, a placement step, and a molding step.
In the insert step, the insert member is mounted on the second mold, and the insert member is attached.
In the arrangement step, with the insert member mounted on the second mold, a foamed resin in a molten mold state is hung between the first and second molds.
The insert member includes a main body portion and an extending portion extending from the main body portion, and the extending portion is embedded in the foamed resin in the molding step.
The molding step includes an expansion step.
The expansion step is a method of expanding the foamed resin by sucking it under reduced pressure. The molding step includes an expansion step.
In the expansion step, the first and second molds are brought close to each other so that a gap larger than the thickness of the foamed resin is provided between the first and second molds. By sucking the foamed resin under reduced pressure with both molds, the foamed resin is expanded to the thickness of the gap.
The method according to claim 6. The expansion step includes a first suction step, a mold proximity step, and a second suction step in this order.
In the first suction step, the foamed resin is sucked under reduced pressure by the first mold to shape the foamed resin into a shape along the cavity of the first mold.
In the mold proximity step, the first and second molds are brought close to each other so that the gap is provided between the first and second molds.
In the second suction step, the foamed resin is sucked under reduced pressure by the first and second molds to expand the foamed resin to the thickness of the gap.
The method according to claim 7. The second mold includes a convex portion that surrounds the mounting portion of the insert member.
In the expansion step, the convex portion presses the foamed resin to form a groove in the foamed resin.
The method according to claim 7 or 8.

Images