Having a foaming mold in which channels are formed and a physical foaming method using the mold

Abstract

The present disclosure relates to a foaming molding die having a channel formed therein and a physical foaming method using the same, and more particularly, to a foaming molding die characterized by including a cavity for accommodating a mixed resin for foaming formed therein, and having a channel for guiding a gas to the cavity formed therein.

Description

Technical Field

[0001] This disclosure relates to a foaming mold in which channels are formed and a physical foaming method using the mold. More specifically, the foaming mold is characterized by including a cavity formed therein for containing a foaming mixed resin and having channels formed therein for guiding gas into the cavity. Background Technology

[0002] Polymer foaming methods can be mainly divided into chemical foaming methods and physical foaming methods. Chemical foaming methods are used in various fields, including the preparation of elastomer foams for cushioning materials such as insoles or midsoles in the footwear industry. Due to its simplicity and high productivity, it is the most widely used method. Chemical foaming follows the sequence of mixing the chemical foaming agent, molding, heating, and foaming. However, during the chemical foaming process, the chemical foaming agent (JTR-azodicarbonamide) decomposes upon heating, producing harmful substances such as formamide or ammonia, causing environmental problems. Therefore, environmentally friendly regulations have been enacted.

[0003] To address this issue, a physical foaming method is currently being developed in related technical fields, which involves directly injecting and dissolving gas into resin for foaming. Physically foamed products prepared using this method are being used in high-priced running shoes and other products.

[0004] The physical foaming method mainly consists of four steps: (a) filling a high-pressure chamber with gas; (b) dissolving and saturating the gas in the polymer to prepare a single-phase mixture; (c) inducing the thermodynamic instability of the mixture by heating or releasing the pressure, thereby generating bubbles in the polymer; and (d) foaming.

[0005] Among them, the methods that induce thermodynamic instability are mainly divided into two types: (1) phase separation by heating the mixture, and (2) phase separation by instantaneous pressure release.

[0006] Among them, (1) the heating foaming method is currently the most commonly used two-step heating foaming method. This method involves saturating the gas in a low-temperature ultra-high pressure autoclave, taking it out after about 48 hours, and heating it in an oil bath to slowly foam. This requires a long time and expensive equipment, such as an autoclave, so the unit production cost is very high. In addition, the current physical foaming method can only foam in sheet and bead form, so it needs to be shaped by post-processing. Therefore, in order to overcome these disadvantages, it is necessary to (2) use a one-step method of phase separation by instantaneous pressure release.

[0007] Therefore, in the process of researching to solve the above-mentioned problems, the inventors of this disclosure developed a physical foaming method that simplifies the process, reduces time, and prepares foams that meet the required performance, and have applied for a patent (patent application number: 10-2019-0164422). However, in the case of the invention of this application, since the gas inlet for injecting gas is formed directly corresponding to the cavity containing the foaming mixed resin, the gas inlet is blocked due to the backflow of the foaming mixed resin, and therefore the gas injection does not proceed smoothly.

[0008] Therefore, in the process of further researching and solving this problem, the inventors discovered that if a channel for guiding gas to the cavity containing the foaming mixed resin is formed in the foaming mold, blockage of the gas inlet can be prevented, gas injection can become smooth, and mold cleaning can become easy, thus reducing processing time, thereby completing the present invention.

[0009] In this regard, Korean Patent No. 10-0554781 discloses a method for gas injection molding of fiber-reinforced resin and a molded article. Summary of the Invention

[0010] Technical issues

[0011] This invention was developed to address the problems of the prior art. The purpose of this invention is to provide a foaming molding mold comprising a cavity for containing a foaming mixed resin and having channels formed therein for guiding gas into the cavity.

[0012] Another object of the present invention is to provide a physical foaming method for preparing foamed materials using a foaming molding die.

[0013] Another object of the present invention is to provide a foamed body prepared by the physical foaming method.

[0014] Technical solution

[0015] As a technical means to solve the above-mentioned technical problems, according to one aspect of the present invention...

[0016] A foaming molding die 1 is provided, comprising: an upper die 10 having a gas inlet 15; and a lower die 20 including an internally formed cavity 30 for containing a foaming mixed resin, wherein the lower die 20 has channels 40, 50 formed therein for guiding gas supplied from the gas inlet 15 to the cavity 30.

[0017] The upper mold 10 and the lower mold 20 can be disassembled from each other.

[0018] Cavity 30 can be formed at the center of lower mold 20, and channels 40 and 50 can be formed on the outer surface of cavity 30.

[0019] Channels 40 and 50 may include a first channel 40 for primarily containing gas supplied from gas inlet 15; and a second channel 50 for guiding gas supplied from the first channel 40 to cavity 30.

[0020] The second channel 50 can be formed on the outer surface of the cavity 30 in a horizontal direction, and the first channel 40 and the cavity 30 can be separated from each other by the second channel 50.

[0021] Foaming compound resins can be in solid form.

[0022] The foaming compound resin can be in solid form, either in sheets or granules.

[0023] It can accommodate foaming mixed resin, allowing it to occupy 50% to 110% of the cavity volume.

[0024] The gas may include gases selected from nitrogen, carbon dioxide, supercritical carbon dioxide, argon, helium, and combinations thereof.

[0025] According to another aspect of the invention,

[0026] A physical foaming method for preparing a foamed body using the foaming molding mold 1 is provided, comprising the following steps: injecting a foaming mixed resin into a cavity 30; sealing the cavity 30 using an upper mold 10; injecting gas into the cavity 30; maintaining a constant pressure inside the cavity 30 so that the injected gas dissolves in the foaming mixed resin; and opening the cavity 30 to release the pressure, thereby performing foaming.

[0027] The sealing of cavity 30 can be achieved at 100 to 200 kgf / cm². 2 It was carried out under pressure.

[0028] The gas injected into cavity 30 can be pressurized to a pressure of 5 to 20 MPa and then injected.

[0029] The step of dissolving the gas in the foaming mixed resin can be carried out at a pressure of 5 to 20 MPa.

[0030] The step of dissolving the gas in the foaming mixed resin can be carried out for 1 to 100 minutes.

[0031] The foaming process can be carried out simultaneously with the demolding of the foamed body, which is formed into a cavity.

[0032] The temperature inside cavity 30 can be between 50 and 200°C.

[0033] According to yet another aspect of the invention,

[0034] A foamed body prepared by the physical foaming method is provided.

[0035] Beneficial effects

[0036] As explained, since the foaming mold according to this disclosure has channels formed therein for guiding gas to the cavity containing the foaming mixed resin, blockage of the gas inlet can be prevented, gas injection can be facilitated, and the mold can be easily cleaned, thereby shortening the processing time.

[0037] Furthermore, the physical foaming method using foaming molds does not use chemical foaming agents, making it environmentally friendly and reducing processing time, thus enabling the preparation of foams with improved performance at low cost.

[0038] Furthermore, the processing conditions are easily changed, thus the cell structure of the foam can be controlled, thereby controlling mechanical properties such as STS (split tear strength) and resilience. Attached Figure Description

[0039] Figure 1 This is a schematic diagram illustrating a foaming molding die according to an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram illustrating a comparative foaming mold according to the present invention.

[0041] Figure 3 This is a schematic diagram illustrating a physical foaming method according to an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram illustrating a physical foaming method using a foaming mold according to one embodiment.

[0043] Figure 5a and 5b The images shown are photographs illustrating a foaming mold according to an embodiment of the present invention.

[0044] Figure 6 This is a photograph showing a foam prepared according to an embodiment of the present invention.

[0045] Figure 7 This is a photograph showing a foam prepared according to a comparative example of the present invention. Detailed Implementation

[0046] The embodiments of the present invention will now be explained in detail to enable those skilled in the art to readily implement the invention. However, the present invention can be implemented in various forms and is not limited to the embodiments described herein.

[0047] Example 1. Preparation of foamed body

[0048] Use such as Figure 1 The foaming mold shown is used to prepare the foamed body. Specifically, a nucleating agent (CaCO3, 4g) and a crosslinking agent (DCP, 0.48g) are added to 95g (95% of the total cavity volume) of a mixed resin for sheet foaming, and then it is injected into a pressure cavity at 150kgf / cm³. 2 The cavity was sealed under pressure, and then nitrogen gas at 15 MPa was introduced into the cavity. Then, the gas was saturated in the resin at a cavity temperature of 150°C for 30 minutes, and then the cavity was opened instantaneously to prepare the foam.

[0049] Example 2. Preparation of foamed body

[0050] Except for injecting 105g (105% of the total cavity volume) of foaming mixed resin, the foam was prepared by the same method as in Example 1.

[0051] Comparative Example. Preparation of Foamed Materials

[0052] In addition to using, such as Figure 2 Except for the foaming molding mold shown, the foam body is prepared by the same method as in Example 1.

[0053] Experimental Example: Comparison of Appearance and Properties of Foamed Materials

[0054] To compare the appearance of the foams prepared in the examples and comparative examples, they were photographed and are shown below. Figure 6 (Example) and Figure 7 In the (comparative example). Among them, Figure 6 The photograph shown on the left shows the foam prepared using the method of Example 1. Figure 6 The photograph shown on the right is of the foam prepared using the method of Example 2.

[0055] See Figure 6 and Figure 7 It can be confirmed that the foam prepared by the embodiments of the present invention has a smooth surface, while the foam prepared according to the comparative example has protrusions formed on the surface. That is, it can be confirmed that in the foam prepared according to the comparative example, protrusions are generated because the gas inlet is positioned so that it can directly correspond to the cavity.

[0056] Meanwhile, it was confirmed that when the foam was prepared according to the example, the gas injection proceeded smoothly, and therefore the prepared foam exhibited a low specific gravity (0.22 g / cc), while when the foam was prepared according to the comparative example, the gas injection was not smooth, and therefore the prepared foam exhibited a high specific gravity (0.37 g / cc).

[0057] Invention Embodiments

[0058] The invention will now be explained in more detail. However, the invention can be embodied in various forms and is not limited to the embodiments described herein, but is defined only by the claims described below.

[0059] Furthermore, the terminology used herein is for illustrative purposes only and is not intended to limit the invention. Singular expressions include their plural expressions unless explicitly stated or clearly apparent from the context. Throughout this specification, unless otherwise stated, “including” any constituent element does not mean excluding other constituent elements, but rather means that other constituent elements may also be included.

[0060] According to a first aspect of the invention,

[0061] A foaming molding die 1 is provided, comprising: an upper die 10 having a gas inlet 15; and a lower die 20 including an internally formed cavity 30 for containing a foaming mixed resin, wherein the lower die 20 has channels 40, 50 formed therein for guiding gas supplied from the gas inlet 15 to the cavity 30.

[0062] The following is for reference Figure 1 and Figure 2 The foaming molding die 1 according to the first aspect of the present invention will be described in detail. Figure 1 This is a schematic diagram showing a foaming molding die 1 according to one embodiment of the present invention. Figure 2 A schematic diagram illustrating a comparative foaming mold 100 according to the present invention.

[0063] According to one embodiment of the present invention, a foaming mold 1 can be used to prepare high-performance foams by foaming based on a physical foaming agent, which are used to manufacture insoles, midsoles, outsoles, etc. of shoes. That is, to prepare the foam, the present invention employs a physical foaming method, and within this physical foaming method, a one-step pressure-release foaming method is used in which foaming and molding are performed simultaneously. Therefore, the foaming mold 1 can be a mold for a pressure-release foaming method, through which foams are prepared. The total processing time is similar to that of existing chemical foaming methods (40-60 minutes), and the processing conditions can be easily changed, thereby easily controlling the performance of the foam. Furthermore, the unit of pressure will be kgf / cm². 2 Both MPa and 1 MPa. 1 MPa is equivalent to approximately 10.197162 kgf / cm³. 2 .

[0064] According to one embodiment of the present invention, the upper mold 10 may have a gas inlet 15 installed therein. That is, as... Figure 1As shown, the upper mold 10 may have a gas inlet 15 extending through its interior for injecting gas from the upper side to the lower side, and the gas supplied through the gas inlet 15 can be sent into the cavity 30 of the lower mold 20. Furthermore, through the gas inlet 15, the gas can preferably be injected from a total of two paths corresponding to both sides of the upper mold 10, such as... Figure 1 As shown, gas can be injected from a total of four paths corresponding to each side. These are closely related to the channels 40 and 50 formed in the lower mold 20, which will be explained in detail below.

[0065] According to one embodiment of the present invention, the lower mold 20 may have a cavity 30 formed therein for accommodating the foaming mixed resin. The cavity 30 is also called a mold cavity, and it can refer to an empty space formed during the assembly of a template, or a device having such an empty space formed therein. In this invention, the empty space itself will be referred to as the cavity 30, such as... Figure 1 As shown, on the upper side of the lower mold 20, some parts can be recessed to the lower side to form a step difference, wherein the cavity 30 can refer to the recessed part.

[0066] According to one embodiment of the invention, the upper mold 10 and the lower mold 20 are detachable from each other. That is, in the separated state, a foaming mixed resin can be injected into the cavity 30 of the lower mold 20, and they can be compressed and sealed. Gas can then be injected and dissolved in the foaming mixed resin, and the pressure can be released again to perform foaming. While the shapes of the upper mold 10 and the lower mold 20 are not significantly limited, they can be designed so that the interior can be completely sealed and disconnected from the outside when compressed.

[0067] According to one embodiment of the present invention, the cavity 30 may be formed at the center of the lower mold 20, and channels 40 and 50 may be formed on the outer surface of the cavity 30. Specifically, see... Figure 1 The shape of cavity 30 is not explicitly limited, but it may have to be formed at the center of lower mold 20. Furthermore, channels 40 and 50 may be formed on the upper side of lower mold 20, and they may be formed between the outer surface of cavity 30 and the end stage of lower mold 20. Therefore, gas supplied through gas inlet 15 of upper mold 10 can be preferentially supplied to channels 40 and 50, and can move along channels 40 and 50 and be supplied to cavity 30.

[0068] According to one embodiment of the invention, channels 40 and 50 may include a first channel 40 for primarily containing gas supplied from gas inlet 15; and a second channel 50 for guiding the gas supplied from the first channel 40 to cavity 30. (See reference) Figure 1Specifically, the first channel 40 can be formed between the outer surface of the cavity 30 and the end platen of the lower mold 20, and can be spaced apart from the outer surface and the end platen at regular intervals. Simultaneously, the first channel 40 can primarily accommodate gas supplied from the gas inlet 15, and for this purpose, the gas inlet 15 can be installed such that it corresponds to the position of the first channel 40. Furthermore, as described above, through the gas inlet 15, gas can preferably be injected along a total of two paths corresponding to both sides of the upper mold 10, or it can be injected along a total of four paths corresponding to each side, so that the gas can be uniformly injected into the first channel 40, and finally, the gas can be uniformly injected into the entire space of the cavity 30.

[0069] According to one embodiment of the present invention, the second channel 50 may be formed horizontally on the outer surface of the cavity 30, and the first channel 40 and the cavity 30 may be spaced apart from each other by the second channel 50. That is, as Figure 1 As shown, the second channel 50 can have a constant width and be formed horizontally on the outer surface of the cavity 30, and can be formed omnidirectionally with the central cavity 30. Meanwhile, Figure 5a and Figure 5b This is an actual photograph showing a foaming molding die 1 according to an embodiment of the present invention, and see also... Figure 5a and Figure 5b One or more second channels 50 may be formed on each side with the cavity 30 as the center. Furthermore, since the first channel 40 and the cavity 30 are spaced apart from each other by the second channels 50, the distance between the gas inlet 15 and the cavity 30 is also spaced. Therefore, blockage of the gas inlet 15 caused by the foaming mixed resin contained in the cavity 30 can be prevented, and gas injection can become smooth and cleaning of the mold 1 itself can become easier, thereby shortening processing time.

[0070] According to one embodiment of the present invention, Figure 2 A comparative foaming molding die 100 according to the present invention is shown, wherein the foaming molding die 100 comprises only an upper die 110 having a centrally mounted gas inlet 120, a lower die 130 having a cavity 150 formed therein for containing a foaming mixed resin, and does not include any additional channels. That is, when using according to Figure 2In the case of the foaming mold 100, since the gas inlet 120 is formed so that it directly corresponds to the cavity 150, the distance between the gas inlet 120 and the cavity 150 is relatively short. This can lead to the gas inlet 120 being blocked by the backflow of the foaming mixed resin, resulting in difficulties in gas injection and cleaning the mold 1 itself. Furthermore, since the gas is directly supplied to the foaming mixed resin, protrusions may form on the upper surface of the prepared foam, leading to quality degradation.

[0071] According to one embodiment of the present invention, the foaming compound resin may be a resin comprising, but is not limited to, ethylene-vinyl acetate copolymer (EVA) and an olefin-based elastomer. Ethylene-vinyl acetate copolymer (EVA) is a polymer obtained by copolymerizing ethylene and vinyl acetate, while the olefin-based elastomer may refer to a polymer obtained by copolymerizing ethylene and α-olefins. Furthermore, the foaming compound resin may be in solid form, and preferably in sheet or granular solid form. In addition, the foaming compound resin can be contained such that it occupies 50% to 110% of the volume of the cavity 30. That is, the foaming molding die 1 further has a first channel 40, a second channel 50, and a cavity 30, which can contain more than 100% of the volume of the foaming compound resin in the cavity 30.

[0072] According to one embodiment of the present invention, the gas may include a gas selected from nitrogen, carbon dioxide, supercritical carbon dioxide, argon, helium and combinations thereof.

[0073] According to a second aspect of the invention,

[0074] A physical foaming method is provided for preparing a foamed body using a foaming mold 1 according to the first aspect, comprising the following steps: injecting a foaming mixed resin into a cavity 30; sealing the cavity 30 using an upper mold 10; injecting gas into the cavity 30; maintaining a constant pressure inside the cavity 30 so that the injected gas dissolves in the foaming mixed resin; and opening the cavity 30 to release the pressure, thereby performing foaming.

[0075] According to a third aspect of the invention,

[0076] A foamed body prepared by the physical foaming method of the second aspect of the present invention is provided.

[0077] Although detailed descriptions of portions overlapping with the first aspect of the invention have been omitted, the same content explained with respect to the first aspect of the invention applies to the second and third aspects of the invention.

[0078] The following will refer to Figure 3 and Figure 4The physical foaming method using the foaming mold 1 according to the second and third aspects of the present invention and the foamed body prepared therefrom are described in detail step by step. Figure 3 To illustrate the physical foaming method, Figure 4 This is a schematic diagram illustrating a physical foaming method using a foaming mold 1.

[0079] First, according to one embodiment of the present invention, the physical foaming method using the foaming molding die 1 may include the step of injecting a foaming mixed resin into the cavity 30.

[0080] According to one embodiment of the present invention, the foaming blended resin may be a resin comprising, but is not limited to, ethylene-vinyl acetate copolymer (EVA) and an olefin-based elastomer. Ethylene-vinyl acetate copolymer (EVA) is a polymer obtained by copolymerizing ethylene and vinyl acetate, while the olefin-based elastomer may refer to a polymer obtained by copolymerizing ethylene and α-olefins. Furthermore, the foaming blended resin may be in solid form, and preferably in solid form as sheets or granules. Additionally, the foaming blended resin may be contained such that it occupies 50% to 110% of the volume of the cavity 30.

[0081] Next, according to one embodiment of the present invention, the physical foaming method using the foaming molding die 1 may include the step of sealing the cavity 30 using the upper die 10.

[0082] According to one embodiment of the present invention, the closure of cavity 30 can be between 100 and 200 kgf / cm². 2 It was carried out under pressure.

[0083] Next, according to one embodiment of the present invention, the physical foaming method using the foaming molding die 1 may include the step of injecting gas into the cavity 30.

[0084] According to one embodiment of the present invention, the gas injected into the cavity 30 can be pressurized to a pressure of 5 to 20 MPa and injected. When pressurized to a pressure below 5 MPa, the efficiency of the injected gas permeating into the foaming resin mixture may decrease, while when pressurized to a pressure above 20 MPa, the device load may increase. The injected gas may include a gas selected from nitrogen, carbon dioxide, supercritical carbon dioxide, argon, helium, and combinations thereof.

[0085] Next, according to one embodiment of the present invention, the physical foaming method using the foaming molding die 1 may include the step of maintaining a constant pressure inside the cavity 30 to dissolve the injected gas in the foaming mixed resin.

[0086] According to one embodiment of the invention, the step of dissolving the gas in the foaming mixed resin can be carried out at a pressure of 5 to 20 MPa and can be performed for 1 to 100 minutes. The total time required for the physical foaming method depends on this step, and preferably, it can be maintained for 30 to 70 minutes, allowing for a processing time similar to that of conventional chemical foaming. Compared to conventional physical foaming methods (heating methods) that induce thermodynamic instability through heating, where the foaming mixed resin is removed and heated approximately 48 hours after gas saturation for slow foaming, the physical foaming method according to the invention significantly improves time efficiency.

[0087] Next, according to one embodiment of the present invention, the physical foaming method using the foaming molding die 1 may include the step of opening the cavity 30 to release the internal pressure to perform foaming.

[0088] According to one embodiment of the invention, the foaming step may include opening the cavity 30 to release internal pressure, thereby initiating foaming. That is, if the cavity 30 is opened instantaneously, pressurized gas can be expelled, and atmospheric pressure can be applied to the cavity 30, thus potentially inducing thermodynamic instability. Evaporation of the gas impregnated in the foaming resin mixture may be triggered, and the foaming resin mixture used for foaming can expand and foam. Furthermore, during foaming, the foamed body, molded into a chamber form, can be demolded. Therefore, it may be preferable when foaming and molding are performed simultaneously in one step, as post-processing for molding may not be necessary. The shape of the foamed body can be formed such that it corresponds to the shape of the internal space of the cavity 30.

[0089] According to one embodiment of the present invention, the temperature of the cavity can be maintained at 50 to 200°C, preferably at 90 to 180°C.

[0090] According to one embodiment of the present invention, during the foaming process, the pore size of the foam can be controlled to be from 5 μm to 1 mm. Furthermore, the pore size can be controlled such that the maximum pore size is controlled to be 40 μm, and so on.

[0091] Although the invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the scope of the invention is not limited to these drawings and embodiments. Therefore, various modifications or embodiments within the scope of the invention's concept are possible. Accordingly, the scope of the invention's concept should be interpreted by the claims and should be understood as encompassing any concept within the same or equivalent scope as the invention.

[0092] [Explanation of reference numerals in the attached figures]

[0093] 1,100: Foaming molding mold

[0094] 10, 110: Upper mold

[0095] 15, 120: Gas inlet

[0096] 20, 130: Lower mold

[0097] 30, 150: Cavity

[0098] 40: First Channel

[0099] 50: Second Channel

[0100] [Industrial Applicability]

[0101] As described above, since the foaming mold according to this disclosure has a channel formed therein for guiding gas to the cavity containing the foaming mixed resin, blockage of the gas inlet can be prevented and gas injection can be promoted. At the same time, the mold can be easily cleaned, thereby reducing processing time.

[0102] Furthermore, the physical foaming method using foaming molds does not use chemical foaming agents, making it environmentally friendly and reducing processing time, thus enabling the preparation of foams with improved performance at low cost.

[0103] Furthermore, the processing conditions are easily changed, thus the cell structure of the foam can be controlled, thereby controlling mechanical properties such as STS (split tear strength) and resilience.

Claims

1. A foaming molding mold (1) comprising: an upper mold (10) having a gas inlet (15) through which a gas is injected from a total of two paths corresponding to both sides of the upper mold (10), or, a total of four paths corresponding to each side of the upper mold (10); a lower mold (20) including an internally formed cavity (30) for accommodating a mixed resin for foaming, wherein the lower mold (20) has channels (40, 50) formed therein for guiding the gas supplied from the gas inlet (15) to the cavity (30), and wherein the channels (40, 50) include a first channel (40) for mainly accommodating the gas supplied from the gas inlet (15); and a second channel (50) for guiding the gas supplied from the first channel (40) to the cavity (30), wherein the first channel (40) and the cavity (30) are formed to be spaced apart from each other by the second channel (50), and the second channel (50) has a constant width and is formed on the outer surface of the cavity (30) in a horizontal direction, and is formed omnidirectionally with the cavity (30) being centered, respectively, and wherein the cavity (30) is formed at the center of the lower mold (20), and the channels (40, 50) are formed on the outer surface of the cavity (30), the channels (40, 50) are formed on the upper side of the lower mold (20), and they are formed between the outer surface of the cavity (30) and the end stage of the lower mold (20).

2. The foam molding mold (1) according to claim 1, wherein The upper mold (10) and the lower mold (20) can be detached from each other.

3. The foam molding mold (1) according to claim 1, wherein The mixed resin for foaming is in a solid form.

4. The foam molding mold (1) according to claim 3, wherein The mixed resin for foaming is in a solid form of a sheet or a particle.

5. The foam molding mold (1) according to claim 1, wherein The mixed resin for foaming is accommodated so as to occupy 50% to 110% of the volume of the cavity (30).

6. The foam molding mold (1) according to claim 1, wherein The gas includes a gas selected from the group consisting of nitrogen, carbon dioxide, argon, helium, and combinations thereof.

7. The foam molding mold (1) according to claim 6, wherein The gas includes supercritical carbon dioxide.

8. A physical foaming method of preparing a foam using the foaming molding mold (1) according to claim 1, comprising the steps of: injecting a mixed resin for foaming into the cavity (30); closing the cavity (30) using the upper mold (10); injecting a gas into the cavity (30); maintaining the pressure inside the cavity (30) constant so that the injected gas is dissolved in the mixed resin for foaming; and opening the cavity (30) to release the pressure, thereby foaming. The gas injected into the cavity (30) is pressurized to a pressure of 5 to 20 MPa and injected.

9. The physical foaming method using a foam molding mold (1) according to claim 8, wherein, The closing of the cavity (30) is performed under a pressure of 100 to 200 kgf / cm 2 .

10. The physical foaming method using a foam molding mold (1) according to claim 8, wherein The step of dissolving the gas in the mixed resin for foaming is performed at a pressure of 5 to 20 MPa.

11. The physical foaming method using a foam molding mold (1) according to claim 8, wherein The step of dissolving the gas in the mixed resin for foaming is performed for 1 to 100 minutes.

12. The physical foaming method using a foam molding mold (1) according to claim 8, wherein, The step of foaming is performed while demolding the foam formed into a chamber form.

13. The physical foaming method using a foam molding mold (1) according to claim 8, wherein The temperature inside the cavity (30) is 50 to 200°C.

14. The physical foaming method using a foam molding mold (1) according to claim 8, wherein ​ 15. A foam prepared by the physical foaming method according to claim 8.

16. A shoe comprising the foam according to claim 15 as an insole, a midsole or an outsole.

Images