JP2019059165A - Foam resin molding method - Google Patents

Abstract

To provide a method for producing a foamed resin molded article which is excellent in a designability of a design surface.SOLUTION: A method for molding a foamed resin molded article 7 has an injection process for injecting a foamed resin raw material 90 into a cavity 8 of a foaming mold 1, and a core back process for moving a core back part 20mp which is a part of the foaming mold 1 in a direction away from a regulating mold part 1cp which is at least a part of the other parts of the foaming mold. An entire design surface 77 of the foamed resin molded article 7 is molded by the regulating mold part 1cp, and at least a part of the foamed resin molded article 7 other than the design surface 77 is molded by the core back part 20mp.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of molding a foamed resin molded body by a core back molding method.

  In recent years, weight reduction is desired for various devices, and weight reduction of a resin molded product as a component of the device is also desired. As one of the methods of reducing the weight of the resin molded body, there is a method of foaming a resin material. A molded article made of a foamed resin material, that is, a foamed resin molded article has many pores in its inside. Since the pores contain gas, the foamed resin molded article has a relatively low density and is lightweight.

As a foamed resin molding method for molding a foamed resin molding, a core back molding method is known (see, for example, Patent Document 1).
The core back molding method is also referred to as a moving cavity method, and is a molding method in which the volume of the cavity is increased by moving a part of the foam mold while the foam resin raw material is injected into the cavity of the foam mold. According to the core back molding method, the volume of the cavity can be increased to foam the foamed resin material injected into the cavity. Specifically, fine bubbles in the foamed resin raw material grow due to the increase in the volume of the cavity.

By the way, according to the above-mentioned core back molding method, in order to change the volume of the cavity at the time of molding, it may be difficult to sufficiently control the shape of the obtained foamed resin molded product. In particular, with respect to a design surface which is easily watched by the user among the foamed resin moldings, a foamed resin molding having excellent designability can not be obtained unless its shape can be sufficiently controlled at the time of molding.
Therefore, a technique capable of producing a foamed resin molded article excellent in the designability of the design surface has been desired.

JP, 2010-162809, A

  This invention is made in view of the said situation, and it aims at providing the technique which manufactures the foamed resin molded object which is excellent in the designability of a design surface.

The foamed resin molded article of the present invention for solving the above problems is
Injecting the foamed resin raw material into the cavity of the foam mold, and separating the core back part which is a part of the foam mold with respect to a regulation part which is at least a part of other parts of the foam mold. A core back process for moving in a direction, and a method of molding a foamed resin molded article,
Molding the entire design surface of the foamed resin molded body by the restriction mold portion;
In the foamed resin molding method, at least a part of a portion other than the design surface in the foamed resin molded body is molded by the core back portion.

  According to the foamed resin molding method of the present invention, a foamed resin molded product excellent in the designability of the design surface can be produced.

FIG. 2 is a perspective view schematically showing a foamed resin molded product produced by the foamed resin molding method of Example 1. FIG. 7 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of the first embodiment. FIG. 7 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of the first embodiment. FIG. 7 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of the first embodiment. FIG. 14 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of Example 2. FIG. 14 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of Example 2. FIG. 18 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of the third embodiment. FIG. 18 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of the third embodiment. FIG. 18 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of Example 4. FIG. 18 is an explanatory view schematically showing the inside of the cavity in the foamed resin molding method of Example 4. It is explanatory drawing which represents typically the mode in the cavity in a reference method. It is explanatory drawing which represents typically the mode in the cavity in a reference method. It is explanatory drawing which represents typically the mode in the cavity in a reference method.

  Hereinafter, the foamed resin molding method of the present invention will be described by way of specific examples.

  In addition, unless otherwise indicated, numerical value range "x-y" described in this specification includes the lower limit x and the upper limit y in the range. Then, new numerical ranges can be configured by arbitrarily combining these upper and lower limit values and the numerical values listed in the embodiment. Further, numerical values arbitrarily selected from these numerical ranges can be used as upper and lower numerical values.

  The inventors of the present invention considered the above-mentioned problem, that is, it may be difficult to sufficiently control the shape of the foamed resin molded product obtained by the core back molding method, and speculated as follows. . Hereinafter, the core back molding method in which it is difficult to sufficiently control the shape of the foamed resin molded product will be described based on FIG. 11, FIG. 12 and FIG. Hereinafter, the core back molding method is referred to as a reference method. The reference method is not the core back molding method of the present invention.

  First, in the reference method, as shown in FIG. 11, the foamed resin raw material 190 is injected into the cavity 108 of the foam molding die 101. The foam mold 101 used in the reference method is composed of a first mold 110 and a second mold 120. The second mold 120 has a positive molding surface 121 for molding the design front 160 of the foamed resin molding 107 shown in FIG. 13 and a vertical molding surface 122 for molding the design elevation 150 of the foamed resin molding 107. The first mold 110 has a back mold surface 123 for molding the back surface 140 of the foamed resin molded body 107. The second mold 120 constitutes a core back portion mp in the foam molding mold 101, and the first mold 110 constitutes a stationary part ump in the foam molding mold 101.

  In the reference method, molding of the foamed resin molded body 107 is performed in two steps of an injection step and a core back step.

(Injection process)
In the injection step, the foamed resin raw material 190 is injected into the cavity 108 of the foam mold 101. As shown in FIG. 11, the cavity 108 is formed between the first mold 110 and the second mold 120. At this time, the foamed resin raw material 190 is injected into the entire cavity 108 substantially without a gap.

(Core back process)
In the core back process, as shown in FIG. 12, the second mold 120, that is, the core back portion mp is moved in a direction away from the first mold 110, that is, the stationary portion ump. Hereinafter, the operation of the core back unit mp is referred to as the core back unit mp retreats as necessary. Conversely, operation of the core back unit mp in a direction in which the stationary unit ump and the core back unit mp approach each other is referred to as advancing of the core back unit mp.
When the core back portion mp retracts, a gap s is formed between the foamed resin raw material 190 in the cavity 108 and the core back portion mp, and the volume of the cavity 108 is increased by the gap s. Therefore, the volume of the foamed resin raw material 190 in the cavity 108 can be increased by the space of the gap s, that is, by the increased volume of the cavity 108. For this reason, as shown in FIG. 13, the foamed resin raw material 190 foams, and the fine bubbles present in the foamed resin raw material 190 grow.

  The cavity 108 of the foam mold 101 is partitioned by the mold surfaces 121 to 123 of the foam mold 101. The temperature of the mold surfaces 121 to 123 is generally lower than the temperature of the foamed resin raw material 190 injected into the cavity 108 in the injection step. For this reason, in the injecting step, the foamed resin raw material 190 in contact with the mold surfaces 121 to 123 is cooled before the core back step. Since the cooled foamed resin raw material 190 solidifies, a skin layer 175 with few pores is formed on the surface of the foamed resin raw material 190 in the cavity 108.

In particular, of the foamed resin raw material 190 in the cavity 108, a portion of the corner of the foamed resin molded body 107 which becomes the design corner 179 for which design is required, that is, the planned corner 199 in FIG. It is surrounded by two of 121-123 and cooled by the two mold faces. For this reason, the design corner portion scheduled portion 199 is easily cooled as compared with the other portion of the foamed resin raw material 190 in the cavity 108, and solidification tends to proceed. In other words, the designed corner portion planned portion 199 is considered to have a thicker skin layer 175 as compared to the other portion of the foamed resin raw material 190 in the cavity 108.
Then, it can be said that the designed corner portion planned portion 199 is less likely to be deformed as compared with other portions, and the surface area of the foamed resin raw material 190 in the cavity 108 does not increase much in the designed corner portion planned portion 199.

  By the way, when the core back portion mp retreats and the volume of the cavity 108 increases in the core back step, naturally, the surface area of the cavity 108 also increases. At this time, if the surface area of the foamed resin raw material 190 in the cavity 108 does not increase following the increase of the surface area of the cavity 108, the foamed resin molded body 107 shaped along the cavity 108, ie, the shape is sufficiently controlled. It is difficult to obtain a foamed resin molded body 107.

  In particular, since the designed corner portion planned portion 199 is in a state in which the thick skin layer 175 is already formed by cooling and solidifying before the core back process, the surface area is hard to increase and follows the shape change of the cavity 108 It is difficult to do. As a result, as shown in FIG. 13, the foamed resin molded body 107 obtained by the reference method is considered to have a surface shape with blunt corners which does not conform to the shape of the cavity 108.

If the design front 160 and the design elevation 150 are design faces that are easily watched by the user, the design corner portion 179 configured of the design front 160 and the design elevation 150 is also easily watched by the user.
As described above, according to the reference method, the designability of the foamed resin molded body 107 is lowered by the dull design corner portion 179 which is not as designed.

  The inventor of the present invention finds out the problem of such a reference method and carries out earnest research to find a foamed resin molded product having a design surface constituted by corner portions, which is excellent in the designability of the design surface. I found a way to manufacture. Hereinafter, specific examples will be described as examples, and the foamed resin molding method of the present invention different from the above reference method will be described.

Example 1
In the foamed resin molding method of the first embodiment, a lid of a console box of a vehicle is molded as a foamed resin molded body. FIG. 1 is a perspective view schematically showing a foamed resin molded article produced by the foamed resin molding method of Example 1, and FIGS. 2, 3 and 4 are in a cavity in the foamed resin molding method of Example 1. It is explanatory drawing which represents a mode typically. In detail, the cavity shown in FIGS. 2 to 4 is formed by the mold surface of a portion of the foamed resin molded body which corresponds to the position A-A in FIG. Further, FIG. 2 shows the inside of the cavity in the injection step, FIG. 3 shows the inside of the cavity in the early stage of the core back step, and FIG. 4 shows the inside of the cavity in the late stage of the core back step. Hereinafter, as necessary, the foamed resin molding method of the embodiment is referred to as the molding method of the embodiment, and the foam molding die used for the foamed resin molding method of the embodiment is referred to as the molding die of the embodiment or simply the molding die, The molded product obtained by the foamed resin molding method of the embodiment is referred to as a molded product of the embodiment or simply a molded product.

  The molded body 7 of Example 1 shown in FIG. 1 has a thin box shape having a thin plate-like upper wall 73 having a window-like opening 7op and an upright wall 74 extending from the end face of the upper wall 73.

The molded body 7 of Example 1 has a design elevation 50, a design front 60 and a back 40. The design front 60 is formed by the upper surface of the upper wall 73. The design elevation surface 50 is formed by the inner peripheral surface of the opening 7 op, which is one of the end surfaces of the molded body 7. The design front face 60 and the design elevation face 50 smoothly and continuously arc in the boundary portion, but as a whole, extend in directions intersecting each other. A corner-like portion surrounded by adjacent two faces of the molded body 7 is referred to as a corner 79, and a corner-like portion surrounded by the design elevation 50 and the design front 60 is referred to as a design corner 79d. The design corner 79d constitutes the peripheral portion of the opening 7op. The back surface 40 is configured by the back surface of the upper wall 73 and faces the design front 60. The back surface 40 is continuous with the design elevation 50.
The molded body 7 has a skin layer 75 and a foam layer 76. As shown in FIG. 4, the skin layer 75 constitutes the surface of the molded body 7, and the foam layer 76 constitutes the inside of the molded body 7, that is, the part of the molded body 7 surrounded by the skin layer 75. The foam layer 76 is a portion that is rougher than the skin layer 75 and has more pores than the skin layer 75.

  As shown in FIG. 4, the design surface 77 of the molded body 7 of Example 1 is configured of a design elevation surface 50 and a design front surface 60. The design front 60 has a design front end 61 and a design front general part 62. The design front end portion 61 is a portion on the design elevation surface 50 side in the design front surface 60 and faces the regulation back surface 41 described later. The design corner portion 79 d is a portion of the molded body 7 surrounded by the design elevation surface 50 and the design front end portion 61.

  The molding method of Example 1 will be described below.

(Injection process)
The injection step and the core back step described later are performed using the mold 1 of the first embodiment shown in FIG.
The mold 1 is composed of a first mold 10 and a second mold 20. Among them, the first die 10 is a fixed die, and the second die 20 is a movable die movable toward the first die 10 and away from the first die 10. The second mold 20 is configured of a restricting portion 20 cp and a core back portion 20 mp.

  The cavity 8 of the mold 1 is defined by the positive mold surface 21 and the vertical mold surface 22 of the first mold 10, and the regulated back mold surface 23c and the general back mold surface 23m of the second mold 20. The positive mold surface 21 of the first mold 10 is a mold surface for molding the design front surface 60 of the molded body 7, and the vertical mold surface 22 of the first mold 10 is a mold surface for molding the design elevation surface 50 of the molded body 7. . The positive mold surface 21 and the vertical mold surface 22 smoothly and continuously arc in the boundary portion, but as a whole, extend in directions intersecting with each other. The portion on the vertical surface 22 side of the normal surface 21 is referred to as a design positive surface 21 d, and the other portion is referred to as a general positive surface 21 g. The design surface 77 of the molded body 7 of Example 1 is molded by the positive mold surface 21 and the vertical mold surface 22. A portion of the design surface 77 that constitutes the design corner portion 79 d of the molded body 7 is molded by the design regular surface 21 d and the vertical surface 22.

The regulated back surface 23c and the general back surface 23m of the second mold 20 are arranged side by side on the same plane. The regulated back mold surface 23 c and the general back mold surface 23 m constitute a back mold surface 23 for molding the back surface 40 of the molded body 7.
The control back mold surface 23c is a mold surface of the control portion 20 cp, and the general back mold surface 23m is a mold surface of the core back portion 20 mp. The regulated back surface 23c is adjacent to the vertical surface 22 of the first mold 10 and faces the design regular surface 21d. The general back mold surface 23m is disposed at a distance from the vertical mold surface 22 of the first mold 10, and faces the general positive mold surface 21g. The portions other than the core back portion 20mp in the mold 1 of the first embodiment shown in FIG. 2, that is, the first mold 10 and the restriction portion 20cp are referred to as a restriction portion 1cp.

The restricting portion 20cp and the core back portion 20mp are connected to a drive portion (not shown), and can integrally move forward and backward with respect to the first mold 10. When the restricting portion 20cp and the core back portion 20mp are integrally advanced with respect to the first mold 10, between the second mold 20 configured of the restricting portion 20cp and the core back portion 20mp and the first mold 10 The cavity 8 is formed in
Further, when the restricting portion 20 cp and the core back portion 20 mp integrally retract with respect to the first mold 10, the mold 1 can be opened to expose the inside of the cavity 8.
The core back unit 20mp is operable independently of the restriction unit 20cp. Therefore, the core back portion 20mp can be advanced and retracted with respect to the restriction mold portion 1cp configured by the restriction portion 20cp and the first mold 10.

  In the injection step, the second die 20 including the restricting portion 20 cp and the core back portion 20 mp is advanced with respect to the first die 10 and disposed at the clamping position shown in FIG. A cavity 8 is formed between the second mold 20 and the second mold 20.

[1] Preparation of Foamed Resin Raw Material As a foamed resin raw material, a mixture of 75 parts by mass of polypropylene, 5 parts by mass of sodium hydrogen carbonate and 20 parts by mass of talc is used. Among these, sodium bicarbonate functions as a foaming agent. Specifically, sodium bicarbonate is thermally decomposed to yield sodium carbonate, water and carbon dioxide. Among these, carbon dioxide can constitute air bubbles in the resin material. In addition, since the decomposition reaction rate is increased in the presence of water, foaming of the resin material by the above decomposition reaction can proceed continuously.
The above foamed resin raw material is put into a not-shown foamed resin molding machine, heated and softened to obtain a fluid foamed resin raw material.

[2] Injection of Foamed Resin Raw Material, Clamping, and Holding Pressure Next, the above-mentioned fluid foamed resin raw material is injected into the cavity 8 of the mold 1 through an injection machine (not shown). At this time, as shown in FIG. 2, the foamed resin raw material 90 spreads substantially all over the cavity 8.
In the injection step, the second mold 20 configured of the restriction portion 20 cp and the core back portion 20 mp is a first mold 10 having a force sufficient to maintain the size of the cavity 8 against the fluid pressure by the foamed resin raw material 90. The mold is clamped towards. In other words, the second mold 20 is clamped toward the first mold 10 with a force sufficient to stay in the clamping position shown in FIG. 2 against the fluid pressure of the foamed resin raw material 90. At this time, the foamed resin raw material 90 is at a relatively high temperature, and the mold 1 is also in a heated state. For this reason, at this time, in the cavity 8, the foaming agent contained in the foamed resin raw material 90 is thermally decomposed gradually to generate small bubbles.
After the injection of the foamed resin raw material 90, the holding pressure is maintained by maintaining the internal pressure of the cavity 8 at a predetermined value for 0.5 to 3 seconds while maintaining the clamping force of the second mold 20 described above. I do.

(Core back process)
In the core back step, after the above-described pressure holding, the core back portion 20mp of the second mold 20 is retracted in the direction indicated by the arrow in FIG. At this time, the restricting portion 20 cp of the second mold 20 does not move in the same manner as the first mold 10. Therefore, at this time, the core back portion 20mp retracts with respect to the restriction mold portion 1cp constituted by the first mold 10 and the restriction portion 20cp. As shown in FIG. 3, the volume of the cavity 8 is increased by the amount of retraction of the core back portion 20mp. That is, the volume of the cavity 8 in the core back process is larger than the volume of the cavity 8 in the injection process.
In the core back step of the molding method of Example 1, the distance between the positive mold surface 21 and the restricting reverse mold surface 23c, more specifically, the distance between the design positive mold surface 21d and the restricting reverse mold surface 23c is 2 mm. is there.

At this time, the inside of the cavity 8 has a negative pressure as the volume increases. For this reason, as shown in FIG. 4, the foamed resin raw material 90 in the cavity 8 foams, and the bubbles generated in the foamed resin raw material 90 expand.
Here, in the above-described injection step, the surface of the foamed resin raw material 90 in the cavity 8 is cooled by the mold surfaces 21 to 23 of the mold 1 and solidified. Therefore, the skin layer 75 is formed on the foamed resin raw material 90 in the cavity 8. The foamed resin raw material 90 located inside the skin layer 75 is foamed to be a foamed layer 76. Therefore, in the core back step, the foamed resin raw material 90 in the cavity 8 becomes the foamed resin molded body 7 of a two-layer structure having the skin layer 75 and the foamed layer 76.

  The surface of the foamed resin molded body 7 of Example 1 has a design front 60 molded by the front surface 21 of the first mold 10 and a design elevation surface 50 molded by the vertical surface 22 of the first mold 10; And a back surface 40 molded by the back mold surface 23. More specifically, the design front 60 has a design front end 61 and a design front general part 62. The design front end portion 61 is molded with the design regular mold surface 21 d of the positive mold surface 21, and the design front general part 62 is molded with the general regular mold surface 21 g of the positive mold surface 21. The back surface 40 has a regulated back surface 41 and a general back surface 42. The control back surface 41 is formed by the control back surface 23c of the back mold surface 23, and the general back surface 42 is formed by the general back mold surface 23m of the back mold surface 23.

In the molding method of the first embodiment, the general back surface 42 which is a part of a portion other than the design surface 77 in the molded body 7 is molded by the core back portion 20mp which is retracted in the core back step. As a result, the gap 8s formed in the cavity 8 by the retraction of the core back portion 20mp is a general back mold surface 23m which is the surface of the core back portion 20mp and a portion to be the general back surface 42 of the foamed resin material 90. , Becomes easier to be formed. Therefore, in the molding method of Example 1, it is difficult to control the shape of the general back surface 42 as desired.
However, the general back surface 42 is not the design surface 77 but a portion that is difficult for the user to look at. Therefore, the designability of the molded body 7 of Example 1 is not easily influenced by the designability of the general back surface 42. That is, the shape of the general back surface 42 does not have to be strictly controlled.

  On the other hand, the design surface 77 in the molded body 7 is molded by the restricting mold portion 1cp which does not retreat in the core back process. As a result, even if the core back portion 20mp retracts in the core back process, the portion between the positive mold surface 21 of the control mold portion 1cp and the portion of the foamed resin raw material 90 which becomes the design front 60 and the control mold portion 1cp. Between the vertical mold surface 22 and the portion of the foamed resin raw material 90 to be the design vertical surface 50, the gap 8s is not easily formed. Therefore, the shape of the design surface 77 in the molded body 7 of Example 1 can be controlled to the shape along the mold surfaces 21, 22 and 23c of the restriction mold portion 1cp. Therefore, according to the molding method of Example 1, it is possible to obtain the molded object 7 of Example 1 which is excellent in the designability of the design surface 77.

  In other words, according to the molding method of Example 1, the portion of the molded body 7 that hardly affects the designability is molded with the core back portion 20mp, and the portion of the molded body 7 that greatly affects the designability is the restricted mold portion 1cp By molding in this way, it is possible to obtain a foamed resin molded body 7 excellent in the designability of the design surface 77.

  By the way, as shown in FIG. 4, the surface of the design corner portion 79 d which is one of the corner portions 79 constitutes a part of the design surface 77. Therefore, as shown in FIG. 2, a portion of the foamed resin raw material 90 in the cavity 8 to be the design corner portion 79d, that is, the design corner portion planned portion 90dc is formed of two parts, a vertical surface 22 and a design positive surface 21d. It is cooled by the mold surface. Therefore, a relatively thick skin layer 75 is formed on the design corner portion scheduled portion 90dc. Since the thick skin layer 75 is not easily deformed, the designed corner portion planned portion 90dc is not easily deformed in the core back process.

  According to the molding method other than the molding method of the present invention, for example, in the reference method described above, as shown in FIG. 12, in the core back step, the mold surfaces 121 and 122 of the mold 1 for molding the design corner portion 179 and the foamed resin A gap s is generated between the raw material 90 and the raw material 90. If a thick skin layer 175 is formed on the design corner portion planned portion 199 of the foamed resin raw material 190 in the cavity 108, the foamed resin raw material 90 foams in the core back process, and the volume of the foamed resin raw material 90 increases. The skin layer 75 is not sufficiently deformed, and the design corner portion 179 having a surface shape along the mold surface can not be obtained. Therefore, according to the reference method, it is extremely difficult to control the surface shape of the design corner 179 exactly.

On the other hand, according to the molding method of the first embodiment, as shown in FIGS. 3 to 4, the design corner portion 79 d is molded with the immobile control mold portion 1 cp in the core back process. For this reason, even if the core back portion 20mp retreats in the core back process, the gap 8s is not easily generated between the design corner portion scheduled portion 90dc and the mold surface of the restriction mold portion 1cp.
If the above-mentioned gap 8s which is the original cause of the surface shape defect of the molded body 7 does not occur, the shape of the design corner portion 79d becomes a shape along the mold surface of the mold 1. Therefore, according to the molding method of Example 1, the surface shape of the design corner portion 79d can be strictly controlled, and the molded body 7 excellent in the designability of the design corner portion 79d can be obtained.

  Furthermore, according to the manufacturing method of the first embodiment, the portion of the foamed resin raw material 90 in the cavity 8 which becomes the design corner 79d is the vertical surface 22, the positive surface 21, and the back surface 23c of the restriction mold 1cp. Molding while sandwiching from three directions. For this reason, the gap 8s is further less likely to occur between the design corner portion scheduled portion 90dc and the mold surface of the restriction mold portion 1cp. Therefore, according to the manufacturing method of Example 1, it is possible to control the surface shape of the design corner 79 d more strictly, and it is possible to obtain the molded body 7 more excellent by the design of the design corner 79 d.

In addition, the core back process in the manufacturing method of Example 1 can also be demonstrated as follows.
In the manufacturing method of the first embodiment, as shown in FIGS. 2 to 3, the cavity 8 is formed into a region (A) for molding the design corner portion 79 d of the molded body 7 and the other portion of the molded body 7. It is roughly divided into the area (B) to Then, in the core back step, the increase rate of the volume of the area (A) and the mold area is made smaller than the increase rate of the volume and the mold area of the area (B).

In the first embodiment, the area (A) is an area surrounded by the design regular surface 21 d, the control back surface 23 c, and the vertical surface 22. The area (B) is an area formed between the general back mold surface 23m and the general positive mold surface 21g.
The mold area of the area (A) means the area of the mold surface of the mold 1 that divides the area (A). Similarly, the mold area of the area (B) means the area of the mold surface of the mold 1 which divides the area (B).
Further, the above-mentioned increase rate is the area (A) when the volume or mold area of the area (A) in the injection step is 100% by volume or 100 area% and the retraction of the core back portion 20mp is completed in the core back step. From the percentage of the volume or surface area of

  In the core-back step, the volume and area increase ratio of the region (A) is preferably 10% or less, preferably 5% or less, more preferably 3% or less, and 0% Particular preference is given to

  In the molding method of Example 1, although polypropylene was used as a resin material of the foamed resin raw material 90 and sodium hydrogencarbonate was used as a foaming agent, the combination of the resin material and the foaming agent is not limited to this. The resin material is preferably a thermoplastic resin. As thermoplastic resins other than polypropylene, polyethylene, polystyrene, polyvinyl acetate, acrylonitrile-butadiene-styrene copolymer resin (so-called ABS resin), acrylonitrile-styrene copolymer resin (so-called AS resin), acrylic resin, polyamide, polyacetal, Polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin and the like are exemplified. 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 also not particularly limited, and one having suitable foaming performance and foaming temperature may be appropriately selected according to the resin material to be used. For example, as a foaming agent, a general one that generates a gas by being thermally decomposed can be used. Alternatively, it is also possible to use one that increases in volume due to heat.

  Common blowing agents include inorganic compounds such as sodium hydrogen carbonate, ammonium hydrogen carbonate and ammonium carbonate, azodicarbonamide, 2,2'-azobis 9 isobutyronitrile, azohexahydrobenzonitrile, and diazoaminobenzene Azo compounds such as benzenesulfonyl hydrazide, benzene-1,3-sulfonyl hydrazide, diphenyl sulfone-3,3'-disulfonyl hydrazide, diphenyl oxide-4,4'-disulfonyl hydrazide, 4,4'-oxybis 9 ( Benzenesulfonyl hydrazide), and sulfonyl hydrazide compounds such as para-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.

  As a foaming agent which increases in volume by heat, a capsule foaming agent can be mentioned. The capsule foaming agent refers to one in which a foaming agent is enclosed in an outer shell made of a thermoplastic resin. As the thermoplastic resin constituting the outer shell, a copolymer such as vinylidene chloride, acrylonitrile, acrylic ester, methacrylic ester or the like is used, and as the foaming agent isobutane, pentane, petroleum ether, hexane, heptane, low boiling point halogenation Volatile organic solvents such as hydrocarbons and methylsilane are used. In addition, the said volatile organic solvent is also called an expansion agent.

  In any case, foaming of the foaming agent, for example, generation of gas from the foaming agent, generation of gas by chemical reaction between the foaming agent and the foaming initiator, or increase of gas volume, etc. Air bubbles are formed in the foamed resin raw material. And the said foam | bubble expands or grows in a core back process, The foamed resin molded object of this invention can be obtained.

  In the molding method of the first embodiment, the entire design surface of the molded body and the regulated back surface which is a part of the back surface are molded by the regulated mold portion, and the general back surface which is a part of the other surface of the back is core back Molded in part. However, the restriction mold portion in the molding method of the present invention only needs to mold the entire design surface, and the entire back surface may be molded by the core back portion. Also in this case, as long as the design surface is formed by the portion other than the core back portion in the mold, that is, the restricting mold portion, in the core back process, between the mold surface of the mold and the foamed resin raw material in the cavity. It is hard for a gap to occur. Therefore, also in this case, it is possible to obtain a foamed resin material excellent in the designability of the design surface.

(Example 2)
The foamed resin molding method of Example 2 is substantially the same as the foamed resin molding method of Example 1 except for the shape of the molding die. The shaped product of Example 2 is substantially the same as the shaped product of Example 1 except for the shape of the back surface. 5 and 6 are explanatory views schematically showing the inside of the cavity in the foamed resin molding method of the second embodiment. Specifically, FIG. 5 shows the inside of the cavity in the injection step, and FIG. 6 shows the inside of the cavity in the later stage of the core back step.

  As shown in FIG. 6, the surface of the molded body 7 of Example 2 is a design surface 77 configured of a design front 60 and a design elevation 50, and a back surface 40 configured of a regulated back surface 41 and a general back surface 42; Have. The design surface 77 is a portion that is easily watched by the user, and the back surface 40 is a portion that is hard to be watched by the user. The design front 60 has a design front end 61 and a design front general part 62, and the portion surrounded by the design front end 61 and the design elevation 50 is the same as the design body 7 of the first embodiment. The unit 79d is configured. In the molded body 7 of the second embodiment, a portion on the back surface 40 side of the design corner portion 79 d protrudes. The protrusion is formed in a tubular shape along the circumferential direction of the opening.

  The molding method of Example 2 will be described below.

(Injection process)
The injection step and the core back step described later are performed using the mold 1 of the second embodiment shown in FIG.
The forming die 1 is configured by the first die 10 and the second die 20 as in the first embodiment. The first mold 10 is a fixed mold, and the second mold 20 is a movable mold.

  The first mold 10 of the mold 1 of the second embodiment is the same as the first mold of the mold of the first embodiment. Therefore, the first mold 10 has, as in the first embodiment, the positive mold surface 21 for molding the design front surface 60 of the molded body 7 and the vertical mold surface 22 for molding the design elevated surface 50 of the molded body 7. The regular surface 21 includes a design regular surface 21 d which is a portion on the vertical surface 22 side, and a general regular surface 21 g which is the other portion. The design surface 77 of the molded body 7 of Example 2 is molded by the positive mold surface 21 and the vertical mold surface 22. Further, the design corner portion 79 d of the molded body 7 of Example 2 is molded by the design regular surface 21 d and the vertical surface 22. In the mold 1 of the second embodiment shown in FIG. 5, the restriction mold portion 1 cp which is a portion other than the core back portion 20 mp is configured of only the first mold 10.

The second mold 20 in the mold 1 of the second embodiment is entirely constituted by the core back portion 20mp, and is retracted in the core back process.
As shown in FIG. 5, the second mold 20, that is, the core back portion 20mp has a concave back mold surface 23d and a general back mold surface 23m, as in the first embodiment. The concave back mold surface 23d and the general back mold surface 23m are arranged in a step-like manner. Among these, the concave back surface 23d is adjacent to the vertical surface 22 of the first mold 10 and faces the design regular surface 21d. The general back mold surface 23m is disposed at a distance from the vertical mold surface 22 of the first mold 10, and faces the general positive mold surface 21g. The distance between the positive surface 21 and the concave back surface 23d is larger than the distance between the positive surface 21 and the general back surface 23m. Therefore, the molded body 7 of Example 2 molded by the mold 1 of Example 2 has the projections described above.

In the molding method of the second embodiment, the cavity 8 of the mold 1 includes the positive mold surface 21 and the vertical mold surface 22 of the first mold 10, and the concave back mold surface 23d of the second mold 20 and the general back mold surface 23m. Is defined by
The core back portion 20mp, that is, the second die 20 is connected to a drive portion (not shown), and can be advanced and retracted with respect to the first die 10. As the second mold 20 advances relative to the first mold 10, a cavity 8 is formed between the second mold 20 and the first mold 10.
Further, when the second mold 20 retracts relative to the first mold 10, the mold 1 is opened.

  In the injection step, the second mold 20 is advanced with respect to the first mold 10 and disposed in the clamping position shown in FIG. 5 to form a cavity 8 between the first mold 10 and the second mold 20. .

[1] Preparation of Foamed Resin Raw Material The same foamed resin material as used in Example 1 is used. The foamed resin raw material is heated and softened in the same manner as in Example 1 to form a fluid foamed resin raw material 90.

[2] Injection of Foamed Resin Raw Material, Clamping, and Holding Pressure Next, the fluid foamed resin raw material 90 described above is injected into the cavity 8 of the mold 1 in the same manner as in Example 1. Also in the injection step of the second embodiment, mold clamping and holding pressure are performed in the same manner as the injection step of the first embodiment.

In the molding method of the second embodiment, the distance between the positive mold surface 21 and the concave back mold surface 23 d is larger than the distance between the positive mold surface 21 and the general back mold surface 23 m. Specifically, the distance between the regular surface 21 and the concave back surface 23d is 3.0 mm, and the distance between the positive surface 21 and the general back surface 23 m is 2.0 mm. Therefore, the mold area per unit volume in the cavity 8 in the area (A) surrounded by the design regular mold surface 21 d, the vertical mold surface 22 and the concave back mold surface 23 d is the general positive mold surface 21 g and the general back mold. It is smaller than the area (B) formed between it and the surface 23m. Therefore, in the manufacturing method of the second embodiment, the foamed resin raw material 90 in the area (A) in the cavity 8 is relatively difficult to be cooled by the mold surface of the mold 1 and the high temperature state is easily maintained.
Therefore, in the implantation step of the second embodiment, it is difficult to form the thick skin layer 75 on the design corner portion planned portion 90dc.
In addition, the mold area said here is as having demonstrated in Example 1. FIG.

(Core back process)
In the core back step, after the above-described pressure holding, the core back portion 20mp, that is, the second mold 20 is retracted in the direction indicated by the arrow in FIG. At this time, since the entire second mold 20 is retracted, the distance between the positive mold surface 21 and the concave back mold surface 23 d and the distance between the positive mold surface 21 and the general back mold surface 23 m both increase, The volume and surface area of the cavity 8 increase in (A) and in the region (B).
In the core back process, the distance between the positive mold surface 21 and the concave back mold surface 23d, more specifically, the distance between the design positive mold surface 21d and the concave back mold surface 23d is 3.8 mm.

  At this time, the inside of the cavity 8 has a negative pressure as the volume increases. For this reason, the foamed resin raw material 90 in the cavity 8 foams, and the bubbles generated in the foamed resin raw material 90 expand. The surface of the foamed resin raw material 90 in the cavity 8 is cooled and solidified by the mold surface of the mold 1, and a skin layer 75 is formed on the foamed resin raw material 90 in the cavity 8. The foamed resin raw material 90 located inside the skin layer 75 is foamed to be a foamed layer 76.

  Here, in the molding method of Example 2, the foamed resin raw material 90 in the area (A) of the cavity 8 is difficult to be cooled because the volume is large and the mold area per unit volume is small. Therefore, the thick skin layer 75 is hard to be formed on the foamed resin raw material 90 in the area (A) of the cavity 8, and the foamed resin raw material 90 in the area (A) of the cavity 8 is relatively easily deformed.

  For this reason, the design surface 77 and the design corner portion 79 d of the molded body 7 molded in the region (A) of the cavity 8 are also controlled to the shape along the mold surface by the molding method of the second embodiment. Therefore, according to the molding method of Example 2, the molded object 7 which is excellent in the designability of the design surface 77 is obtained.

The injection step and the core back step in the manufacturing method of the second embodiment can also be described as follows.
In the manufacturing method of the second embodiment, the cavity 8 is divided into a region (A) for molding the design corner portion 79 d of the molded body 7 and a region (B) for molding the other portion of the molded body 7. Generally, in the implantation step, the thickness of the cavity 8 in the area (A) is made larger than the thickness of the cavity 8 in the area (B).
Alternatively, in the injection step, the mold area per unit volume of the area (A) is made smaller than the mold area per unit volume of the area (B).
Alternatively, in the injection step, the volume of the area (A) per unit area of the design front 60 is made larger than the volume of the area (B).
In this way, in the molding method of Example 2, the foamed resin raw material 90 in the area (A) is less likely to be cooled, and the thick skin layer 75 is less likely to be formed on the foamed resin raw material 90 in the area (A). As a result, the foamed resin raw material 90 in the region (A) is easily deformed in the core back process, and the design surface 77 can be shaped according to the shape of the mold surface. Therefore, according to the manufacturing method of Example 2, a molded article excellent in the designability of the design surface 77 is obtained.

In addition, the molded object 7 of Example 2 has a cylindrical protrusion extended toward the back side. For example, as shown in FIG. 1, the molded body 7 may have an upright wall 74 that largely protrudes in the thickness direction. The standing wall 74 and the projections in the molded body 7 of Example 2 can be distinguished by their height. Specifically, the projections in the molded body 7 of Example 2 have a plate thickness of 2.5 mm or less and / or a height of 4.5 mm or less. More preferably, the projections in the molded body 7 of Example 2 have a plate thickness of 2.0 mm or less and / or a height of 4.0 mm or less. With regard to the standing wall 74 whose height and / or thickness exceeds the above range, it is not necessary to particularly consider the shape of the mold 1. In particular, for the standing wall 74 whose plate thickness exceeds 2.0 mm, it is not necessary to consider the shape of the mold 1.
The height of the projection means the total length of the projection in the thickness direction of the upper wall 73 and the length including the upper wall 73. Similarly, the height of the upright wall 74 means the total length of the upright wall 74 in the thickness direction of the upper wall 73 and the length including the upper wall 73.

The height of the projection is the distance between the positive mold surface 21 and the concave back surface 23d in the core back process, more specifically, the design positive mold surface 21 d and the concave back surface 23d in the core back process. It can be reworded as distance. The distance between the designed regular surface 21d and the concave back surface 23d is preferably in the range of 1.0 mm to 5.0 mm, more preferably in the range of 1.0 mm to 4.0 mm, More preferably, it is in the range of 1.0 mm to 3.0 mm.
Further, the height of the projection can also be regarded as the distance between the general back mold surface 23 m and the concave back mold surface 23 d. The preferable distance between the general back mold surface 23m and the concave back mold surface 23d can be in the range of 0.5 mm to 4.0 mm, 2.0 mm to 4.0 mm, and 2.0 mm to 5.0 mm.
Furthermore, the thickness of the upper wall 73 in the molded body 7 is preferably in the range of 1.0 mm to 4.0 mm.

Further, in the molding method of the second embodiment, the regulated back surface 41 and the general back surface 42 of the molded body 7 are molded by the core back portion 20mp which recedes in the core back process. As a result, the gap 8s formed in the cavity 8 by the retraction of the core back portion 20mp is formed by the concave back surface 23d and the general back surface 23m, which are the surface of the core back portion 20mp, and the foamed resin in the cavity 8. It is easy to be formed between the raw material 90 and the portion to be the regulated back surface 41 and the general back surface 42. Therefore, even in the molding method of Example 2, it is difficult to control the shapes of the regulated back surface 41 and the general back surface 42 as desired.
However, similarly to the molded body 7 of Example 1, the regulated back surface 41 and the general back surface 42 are not the design surface 77 but portions that are difficult to be watched by the user, so the designability of the molded body 7 of Example 2 is It is hard to receive the influence of the designability of regulation back side 41 and general back side 42. That is, the shapes of the regulated back surface 41 and the general back surface 42 in the molded body 7 of Example 2 may not be strictly controlled.

On the other hand, the design surface 77 of the molded body 7 is molded by the immobile regulatory mold portion 1cp in the core back process, and is controlled to a shape along the mold surface of the regulatory mold portion 1cp. Therefore, also by the molding method of Example 2, it is possible to obtain the molded object 7 of Example 2 which is excellent in the designability of the design surface 77 similarly to the molding method of Example 1.
That is, according to the molding method of the second embodiment, the portion of the molded body 7 which hardly affects the designability is molded with the core back portion 20mp, and the portion of the molded body 7 which greatly affects the designability is the regulated mold portion 1cp. By molding, it is possible to obtain a foamed resin molded body 7 excellent in the designability of the design surface 77.

(Example 3)
The foamed resin molding method of Example 3 is substantially the same as the foamed resin molding method of Example 1 except for the shape of the molding die. The molded article of Example 3 is substantially the same as the molded article of Example 1 except for the shapes of the design upright surface and the back surface. 7 and 8 are explanatory views schematically showing the inside of the cavity in the foamed resin molding method of the third embodiment. Specifically, FIG. 7 shows the inside of the cavity in the injection step, and FIG. 8 shows the inside of the cavity in the later stage of the core back step.

  As shown in FIG. 8, the surface of the molded body 7 of Example 3 has a design surface 77 configured of a design front surface 60 and a design elevation surface 50, and a back surface 40. The design surface 77 is a portion that is easily watched by the user, and the back surface 40 is a portion that is hard to be watched by the user. The design front 60 has a design front end 61 that is a portion on the design elevation 50 side. The portion surrounded by the design front end portion 61 of the design surface 77 and the design elevation surface 50 constitutes a design corner 79 d in the same manner as the molded body 7 of the first embodiment. In the molded body 7 of Example 3, the portion on the back surface 40 side of the design upright surface 50 has a fine uneven shape, that is, a so-called embossed shape.

  The molding method of Example 3 will be described below.

(Injection process)
The injection step and the core back step described later are performed using the mold 1 of the third embodiment shown in FIG.
The forming die 1 is configured by the first die 10 and the second die 20 as in the first embodiment. The first mold 10 is a fixed mold, and the second mold 20 is a movable mold.

The first mold 10 of the molding die 1 of Example 3 has a regular surface 21 for molding the design front surface 60 of the molded body 7 and a vertical surface 22 for molding the design upright surface 50 of the molded body 7. The regular surface 21 has a design regular surface 21 d which is a portion on the vertical surface 22 side. The portion of the vertical mold surface 22 on the back mold surface 23 side of the second mold 20 is a fine uneven surface.
The design surface 77 of the molded body 7 of Example 3 is molded by the positive mold surface 21 and the vertical mold surface 22. The design corner portion 79 d of the molded body 7 of Example 3 is molded by the design regular surface 21 d and the vertical surface 22.

The entire second mold 20 in the mold 1 of the third embodiment is configured by the core back portion 20mp in its entirety, and is retracted in the core back process. Therefore, in the mold 1 of the third embodiment, the restricting mold portion 1 cp is configured only by the first mold 10.
The second mold 20, ie, the core back portion 20 mp has a flat back surface 23.

In the molding method of the third embodiment, the cavity 8 of the mold 1 is defined by the positive mold surface 21 and the vertical mold surface 22 of the first mold 10 and the back mold surface 23 of the second mold 20.
The core back portion 20mp, that is, the second die 20 is connected to a drive portion (not shown), and can be advanced and retracted with respect to the first die 10.
As the second mold 20 advances relative to the first mold 10, a cavity 8 is formed between the second mold 20 and the first mold 10. Further, when the second mold 20 retracts relative to the first mold 10, the mold 1 is opened.

  In the injection step, the second mold 20 is advanced with respect to the first mold 10 and disposed in the mold clamping position shown in FIG. 7 to form a cavity 8 between the first mold 10 and the second mold 20. .

[1] Preparation of Foamed Resin Raw Material The same foamed resin material as used in Example 1 is used. The foamed resin raw material is heated and softened in the same manner as in Example 1 to obtain a fluid foamed resin raw material 90.

[2] Injection of Foamed Resin Raw Material, Clamping, and Holding Pressure Next, the fluid foamed resin raw material 90 described above is injected into the cavity 8 of the mold 1 in the same manner as in Example 1. Also in the injection step of the third embodiment, mold clamping and holding pressure are performed in the same manner as the injection step of the first embodiment.

  In the molding method of the third embodiment, the portion of the vertical surface 22 on the back surface 23 has an uneven shape. For this reason, the foamed resin raw material 90 also intrudes into the uneven portion of the vertical surface 22. The foamed resin raw material 90 which has entered the uneven portion is cooled by the vertical surface 22 to form a skin layer 75.

(Core back process)
In the core back step, after the above-described pressure holding, the core back portion 20mp, that is, the second mold 20 is retracted in the direction indicated by the arrow in FIG. At this time, since the entire second mold 20 retracts, the distance between the positive mold surface 21 and the back mold surface 23 increases, and the volume and surface area of the cavity 8 increase over the entire area of the cavity 8.

  At this time, the inside of the cavity 8 has a negative pressure as the volume increases. For this reason, as shown in FIG. 8, the foamed resin raw material 90 in the cavity 8 foams, and the bubbles generated in the foamed resin raw material 90 expand. Therefore, the foamed resin raw material 90 in the cavity 8 becomes the foamed resin molded body 7 having the skin layer 75 and the foamed layer 76.

In the molding method of Example 3, the back surface 40 of the molded body 7 is molded by the core back portion 20mp. As a result, the gap 8s formed in the cavity 8 by retraction of the core back portion 20mp becomes the back surface 40 of the back mold surface 23 which is the surface of the core back portion 20mp and the foamed resin material 90 in the cavity 8. It is easy to be formed between the part. Therefore, even in the molding method of the third embodiment, it is difficult to control the shape of the back surface 40 as desired.
However, as with the molded body 7 of Example 1, the back surface 40 is not the design surface 77 but a portion that is hard to be closely watched by the user, so the designability of the molded body 7 of Example 3 is similar to that of the back surface 40 It is hard to be affected. That is, also in the molded body 7 of the third embodiment, the shape of the back surface 40 may not be strictly controlled.

On the other hand, the design surface 77 of the molded body 7 is molded by the immobile regulatory mold portion 1cp in the core back process, and is controlled to a shape along the mold surface of the regulatory mold portion 1cp. Therefore, also by the molding method of Example 3, it is possible to obtain the molded object 7 of Example 3 which is excellent in the designability of the design surface 77 similarly to the molding method of Example 1.
That is, according to the molding method of the third embodiment, the portion which hardly affects the designability of the molded body 7 is molded by the core back portion 20mp, and the portion which largely affects the designability of the molded body 7 is the regulated mold portion 1cp. By molding, it is possible to obtain a foamed resin molded body 7 excellent in the designability of the design surface 77.

  In the molding method of the third embodiment, the skin layer 75 intrudes into the uneven portion of the vertical surface 22 in the injection step. By performing the core back process in this state, the skin layer 75 which has entered the concavo-convex portion of the vertical surface 22 exhibits an anchor effect and is fixed to the vertical surface 22. Therefore, a gap 8 s does not easily occur between the portion of the foamed resin raw material 90 in the cavity 8 which becomes the design front surface 60 and the regular surface 22. By this, according to the molding method of Example 3, the design surface 77 in the molded body 7 can be precisely controlled to the shape along the mold surface of the restriction mold portion 1cp, and the design property of the design surface 77 is excellent. The molded body 7 can be obtained.

The unevenness of the vertical surface 22 may have a shape according to the design required for the design elevation surface 50. As the shape of the unevenness, various shapes represented by, for example, an eyebrow shape and a hairline shape can be mentioned besides the shape of the embossing. The unevenness may be set to such an extent that the above-mentioned anchor effect can be exhibited. For example, in the case of defining the surface roughness, the arithmetic average roughness Ra can be in the range of 0.01 mm to 2 mm. The Ra is preferably in the range of 0.1 mm to 0.5 mm. For reference, the arithmetic mean roughness Ra is defined in JIS B 0601: 2013.
In addition, in order to obtain a more excellent anchor effect, it is preferable that the asperities extend in a direction intersecting with the retracting direction of the core back portion 20mp.

  In the same manner as in the case of the mold according to the third embodiment, the vertical surfaces of the mold according to the first embodiment and the second embodiment may be provided with asperities. In this case, it is possible to impart to the production method of the first embodiment and the production method of the second embodiment the same effects as those of the production method of the third embodiment due to the unevenness.

(Example 4)
The foamed resin molding method of Example 4 is substantially the same as the foamed resin molding method of Example 1 except for the shape of the molding die. The shaped product of Example 4 is substantially the same as the shaped product of Example 1 except for the shape of the back surface. 9 and 10 are explanatory views schematically showing the inside of the cavity in the foamed resin molding method of the fourth embodiment. Specifically, FIG. 9 shows the inside of the cavity in the injection step, and FIG. 10 shows the inside of the cavity in the later stage of the core back step.

  The molding method of Example 4 will be described below.

(Injection process)
The injection step and the core back step described later are performed using the mold 1 of the fourth embodiment shown in FIG.
The forming die 1 is configured by the first die 10 and the second die 20 as in the first embodiment. The first mold 10 is a fixed mold, and the second mold 20 is a movable mold.

The first mold 10 of the molding die 1 of the fourth embodiment has a positive mold surface 21 for molding the design front surface 60 of the molded body 7 and a vertical mold surface 22 for molding the design elevation surface 50 of the molded body 7. The regular surface 21 has a design regular surface 21 d which is a portion on the vertical surface 22 side.
The design surface 77 of the molded body 7 of Example 4 is configured of a design front 60 and a design elevation 50. The part surrounded by the design front end 61 of the design surface 77 and the design elevation surface 50 in the molded body 7 of Example 4 constitutes the design corner 79 d in the same manner as the molded body 7 of Example 1. The design surface 77 is formed by the positive mold surface 21 and the vertical mold surface 22 of the first mold 10. Further, the design corner portion 79 d of the molded body 7 of the fourth embodiment is molded by the design regular surface 21 d and the vertical surface 22 of the first mold 10.

  A fine air vent 25 communicating the inside and the outside of the cavity 8 is provided in a portion on the vertical surface 22 side of the normal surface 21. The air vent 25 penetrates the portion of the first mold 10 that constitutes the positive-shape surface 21 in the thickness direction, and is connected to the decompression pump P, which is a decompression device.

The entire second mold 20 in the mold 1 of the fourth embodiment is constituted by the core back portion 20mp in its entirety, and is retracted in the core back step. Therefore, in the mold 1 of the fourth embodiment, the restricting mold portion 1 cp is configured of only the first mold 10.
The second mold 20, ie, the core back portion 20 mp has a flat back surface 23.

In the molding method of the fourth embodiment, the cavity 8 of the mold 1 is defined by the positive mold surface 21 and the vertical mold surface 22 of the first mold 10 and the back mold surface 23 of the second mold 20.
The core back portion 20mp, that is, the second die 20 is connected to a drive portion (not shown), and can be advanced and retracted with respect to the first die 10.
As the second mold 20 advances relative to the first mold 10, a cavity 8 is formed between the second mold 20 and the first mold 10. When the second mold 20 retracts relative to the first mold 10, the mold 1 is opened.

  In the injection step, the second mold 20 is advanced with respect to the first mold 10 and disposed in the clamping position shown in FIG. 9 to form a cavity 8 between the first mold 10 and the second mold 20. .

[1] Preparation of Foamed Resin Raw Material The same foamed resin material as used in Example 1 is used. The foamed resin raw material is placed in a foamed resin molding machine (not shown), heated and softened to form a fluid foamed resin raw material 90.

[2] Injection of Foamed Resin Raw Material, Clamping, and Holding Pressure Next, the fluid foamed resin raw material 90 described above is injected into the cavity 8 of the mold 1 in the same manner as in Example 1. Also in the injection step of the fourth embodiment, the clamping and holding pressure are performed in the same manner as the injection step of the first embodiment.

  Also in the molding method of the fourth embodiment, the foamed resin raw material 90 in the cavity 8 is cooled by the mold surface, and the skin layer 75 is formed on the foamed resin raw material 90 in the cavity 8.

(Core back process)
In the core back step, the pressure reducing pump P is operated after the above-described pressure holding. Then, the core back portion 20mp, that is, the second mold 20 is retracted in the direction indicated by the arrow in FIG.
At this time, since the entire second mold 20 retracts, the distance between the positive mold surface 21 and the back mold surface 23 increases, and the volume and surface area of the cavity 8 increase over the entire area of the cavity 8.

  At this time, the inside of the cavity 8 has a negative pressure mainly as the volume increases. Therefore, the foamed resin raw material 90 in the cavity 8 foams, and the bubbles generated in the foamed resin raw material 90 expand. Therefore, as shown in FIG. 10, the foamed resin raw material 90 in the cavity 8 becomes the foamed resin molded body 7 having the skin layer 75 and the foamed layer 76.

  By the way, in the molding method of the fourth embodiment, in the core back process, first, the pressure reducing pump P is operated. As described above, in the pouring step, the foamed resin raw material 90 in the cavity 8 is cooled by the mold surface of the mold 1. A portion of the foamed resin raw material 90 in the cavity 8 in contact with the mold surface is a skin layer 75. Therefore, the portion of the foamed resin raw material 90 in the cavity 8 in contact with the positive surface 21 also becomes the skin layer 75. In this state, when the pressure reducing pump P is operated, a suction force is generated in the vent holes 25 and the skin layer 75 in contact with the regular surface 21 is in close contact with and fixed to the regular surface 21 by the suction force.

Therefore, in the core back process of the fourth embodiment, a gap 8 s is not easily generated between the portion to be the design front surface 60 of the foamed resin raw material 90 in the cavity 8 and the regular surface 21. A portion of the foamed resin raw material 90 in the cavity 8 located in the vicinity of the regular surface 21, that is, a portion of the foamed resin raw material 90 to be the design rising surface 50 is also indirectly fixed to the positive surface 21. Therefore, the gap 8s is unlikely to occur between the portion to be the design elevation surface 50 and the vertical surface 22.
Therefore, according to the molding method of the fourth embodiment, the design surface 77 of the molded body 7 can be precisely controlled to the shape along the mold surface of the restricting mold portion 1cp, and the molding of the fourth embodiment is superior to the design property of the design surface 77. You can get the body 7

In the molding method of the fourth embodiment, the back surface 40 of the molded body 7 is molded by the core back portion 20mp. Therefore, the gap 8s formed in the cavity 8 by the retraction of the core back portion 20mp includes the back mold surface 23 which is the surface of the core back portion 20mp and the portion to be the back surface 40 of the foamed resin material 90 in the cavity 8. , Easy to be formed between. Therefore, even in the molding method of Example 4, it is difficult to control the shape of the back surface 40 as desired.
However, as with the molded body 7 of Example 1, the back surface 40 is not the design surface 77 but a portion that is hard to be closely watched by the user, so the designability of the molded body 7 of Example 4 is similar to that of the back surface 40 It is hard to be affected. That is, also in the molded body 7 of Example 4, the shape of the back surface 40 does not have to be strictly controlled.

On the other hand, the design surface 77 of the molded body 7 is molded by the immobile regulatory mold portion 1cp in the core back process, and is controlled to a shape along the mold surface of the regulatory mold portion 1cp. Therefore, also by the molding method of Example 4, it is possible to obtain the molded object 7 of Example 4 which is excellent in the designability of the design surface 77 similarly to the molding method of Example 1.
That is, according to the molding method of the fourth embodiment, a portion which hardly affects the designability of the molded body 7 is molded by the core back portion 20mp, and a portion which largely affects the designability of the molded body 7 is the restricted mold portion 1cp. By molding, it is possible to obtain a foamed resin molded body 7 excellent in the designability of the design surface 77.

  The pressure reducing device only needs to be capable of reducing the pressure in the cavity 8 through the vent 25. The pressure reducing device is not limited to the pressure reducing pump, and various mechanisms can be used.

The number and the size of the vent holes 25 are not particularly limited, and may be appropriately set according to the design required for the design front 60.
In the molding method of the fourth embodiment, the vent holes 25 are provided on the regular surface 21, but the vent holes 25 may be provided on the vertical surface 22. In this case, a pressure reducing device may be connected to the vent 25 provided on the vertical surface 22.

Furthermore, a vent similar to that of the fourth embodiment may be provided on the positive side and / or the vertical side of any of the molds of the first to third embodiments, and a pressure reducing device may be connected to the vent. . In this case, the manufacturing method of the first to third embodiments can be provided with the same effect by the vent as the effect of the manufacturing method of the fourth embodiment.
Furthermore, the mold of the first embodiment or the second embodiment may be provided with the vent hole and the pressure reducing device described above and the same uneven shape as the mold of the third embodiment.

  It is also possible to combine the molding method of the first to fourth embodiments described above with the film insert molding method. That is, the film is previously installed on the positive mold surface of the mold of any of Examples 1 to 4, and the injection step and the core back step are performed in the same manner as any of Examples 1 to 4. Also good. In this case, since a gap does not easily occur between the film and the regular surface also in the core back process, the film can be shaped along the regular surface. In addition, naturally, a gap does not easily occur between the hatched film and the foamed resin raw material, so the foamed resin molded product and the film are integrated with a good design. In this case, similarly to the molding methods of Examples 1 to 4, the foamed resin molded article and the film are integrated, and a film insert molded article excellent in the designability of the design surface is obtained. Since a part of the design surface of the molded article is composed of a film, the molded article is given a design derived from the film.

(Others)
The present invention is not limited to only the embodiments described above and shown in the drawings, and can be appropriately modified and implemented without departing from the scope of the invention. Moreover, each component shown in the embodiment can be arbitrarily extracted and combined and implemented.

  The molding method of the present invention is preferably used as a molding method for producing various articles which are required to be lightweight, such as interior and exterior articles for vehicles.

  The foamed resin molded article of the present invention can be expressed as follows.

(1)
Injection step of injecting the foamed resin raw material 90 into the cavity 8 of the foam molding die 1 and regulation of the core back portion 20mp which is a part of the foam molding die 1 is at least a part of other parts of the foam molding die 1 And a core back process of moving the mold part 1cp in a direction away from the mold part 1cp, wherein the foamed resin molded body 7 is molded,
The entire design surface 77 of the foamed resin molded body 7 is molded by the restriction mold portion 1cp,
A foamed resin molding method, wherein at least a part of a portion other than the design surface 77 in the foamed resin molded body 7 is molded by the core back portion 20mp.
(2)
The foamed resin molded body 7 is
The design surface 77 having a design elevation surface 50 which is one of the end faces of the foamed resin molded body 7; and a design front 60 continuous with the design elevation surface 50 and intersecting the design elevation surface 50;
And a back surface 40 continuous with the design elevation surface 50 and facing the design front surface 60;
The restriction mold portion 1cp forms a portion of the back surface 40 continuous with the design elevation surface 50, the vertical surface 22 for shaping the design elevation surface 50, the normal surface 21 for shaping the design front surface 60, and the like. Control back surface 23c, and
The method for molding a foamed resin according to (1), wherein the core back portion 20mp has a general back mold surface 23m for molding at least a part of the other portion of the back surface 40.
(3)
The foamed resin molded body 7 is
A design surface 77 having a design elevation surface 50 which is one of the end faces of the foamed resin molded body 7; and a design front 60 continuous with the design elevation surface 50 and intersecting the design elevation surface 50;
And a back surface 40 continuous with the design elevation surface 50 and facing the design front surface 60;
The restriction mold portion 1cp forms a portion of the back surface 40 continuous with the design elevation surface 50, the vertical surface 22 for shaping the design elevation surface 50, the normal surface 21 for shaping the design front surface 60, and the like. Forming a concave back surface 23d,
The core back portion 20mp has a general back mold surface 23m for molding at least a part of the other portion of the back surface 40,
The foamed resin molding method according to (1), wherein a distance between the positive mold surface 21 and the recessed step back mold surface 23d is larger than a distance between the positive mold surface 21 and the general back mold surface 23m.
(4)
The foamed resin molded body 7 is
A design surface 77 having a design elevation surface 50 which is one of the end faces of the foamed resin molded body 7; and a design front 60 continuous with the design elevation surface 50 and intersecting the design elevation surface 50;
And a back surface 40 continuous with the design elevation surface 50 and facing the design front surface 60;
The restriction mold portion 1 cp has a vertical surface 22 for molding the design elevation surface 50 and a regular surface 21 for molding the design front surface 60,
The core back portion 20mp has a back mold surface 23 for molding the back surface 40,
The foamed resin molding method according to (1), wherein a portion of the vertical mold surface 22 on the back mold surface 23 side has an uneven shape.
(5)
The foamed resin molded body 7 is
A design surface 77 having a design elevation surface 50 which is one of the end faces of the foamed resin molded body 7; and a design front 60 continuous with the design elevation surface 50 and intersecting the design elevation surface 50;
And a back surface 40 continuous with the design elevation surface 50 and facing the design front surface 60;
The restriction mold portion 1 cp has a vertical surface 22 for molding the design elevation surface 50 and a regular surface 21 for molding the design front surface 60,
The core back portion 20mp has a back mold surface 23 for molding the back surface 40,
The vent hole 25 which connects the inside and outside of the said cavity 8 is provided in the part by the side of the said type | mold surface 22 among the said positive mold surfaces 21, The said vent hole 25 is connected to a pressure reduction device, It is described in (1) Foam resin molding method.
(6)
The foamed resin molding method according to (3), wherein in the core back step, the distance between the positive mold surface 21 and the concave back mold surface 23 d is 4.0 mm or less.

7: Foamed resin molded product 7op: Opening 75: Skin layer 76: Foam layer 77: Design surface 79d: Design corner 40: Back surface 41: Control back surface 42: General back surface 50: Design front surface 60: Design front 61: Design front End 62: Design front general part 90: Foam resin raw material 90 dc: Design corner planned part 1: Foam mold 1 cp: Regulating mold 10: First mold 20: Second mold 20 cp: Regulating part 20 mp: Core back 21 : Normal surface 21d: Design regular surface 21g: General positive surface 25: Air vent 22: Vertical surface 23: Back surface 23c: Restricted back surface 23d: Concave back surface 23m: General back surface 8 : Cavity 8s: Gap P: Decompression pump

Claims (6)

Injecting the foamed resin raw material into the cavity of the foam mold, and separating the core back part which is a part of the foam mold with respect to a regulation part which is at least a part of other parts of the foam mold. A core back process for moving in a direction, and a method of molding a foamed resin molded article,
Molding the entire design surface of the foamed resin molded body by the restriction mold portion;
A foamed resin molding method, wherein at least a part of a portion other than the design surface in the foamed resin molded body is molded by the core back portion. The foamed resin molded body is
The design surface having a design elevation which is one of the end faces of the foamed resin molded body, and a design front which is continuous with the design elevation and intersects the design elevation;
Having a back surface continuous with the design elevation and facing the design front,
The restriction mold portion includes a vertical surface for molding the design elevation, a positive surface for molding the design front, and a regulation back surface for molding a portion of the back surface continuous with the design elevation. Have
The foamed resin molding method according to claim 1, wherein the core back portion has a general back mold surface for molding at least a part of the other portion of the back surface. The foamed resin molded body is
A design surface having a design elevation which is one of the end faces of the foamed resin molded body, and a design front which is continuous with the design elevation and intersects the design elevation;
Having a back surface continuous with the design elevation and facing the design front,
The restriction mold portion has a vertical surface for molding the design elevation, and a regular surface for molding the design front,
The core back portion has a concave back surface that forms a portion of the back surface that is continuous with the design upright surface, and a general back surface that forms at least a portion of the other portion of the back surface.
The foamed resin molding method according to claim 1, wherein a distance between the positive mold surface and the concave back mold surface is larger than a distance between the positive mold surface and the general back mold surface. The foamed resin molded body is
A design surface having a design elevation which is one of the end faces of the foamed resin molded body, and a design front which is continuous with the design elevation and intersects the design elevation;
Having a back surface continuous with the design elevation and facing the design front,
The restriction mold portion has a vertical surface for molding the design elevation, and a regular surface for molding the design front,
The core back portion has a back mold surface for molding the back surface,
The foamed resin molding method according to claim 1, wherein a portion on the back mold surface side of the vertical mold surface has a concavo-convex shape. The foamed resin molded body is
A design surface having a design elevation which is one of the end faces of the resin foam molded body, and a design front which is continuous with the design elevation and intersects the design elevation;
Having a back surface continuous with the design elevation and facing the design front,
The restriction mold portion has a vertical surface for molding the design elevation, and a regular surface for molding the design front,
The core back portion has a back mold surface for molding the back surface,
The foamed resin molding method according to claim 1, wherein a vent hole communicating the inside and the outside of the cavity is provided in a part of the positive mold surface on the vertical surface side, and the vent hole is connected to a decompression device.   The foamed resin molding method according to claim 3, wherein in the core back step, a distance between the positive mold surface and the concave back mold surface is 4.0 mm or less.

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