Method for manufacturing foam and apparatus for manufacturing foam

Abstract

To provide a method for producing a foam which is excellent in homogeneity, and a foam production apparatus for producing a foam which is excellent in homogeneity.SOLUTION: A foam production method includes the steps of: supplying a mixed liquid containing a resin raw material and a foaming agent to inside of a container 2 for transmitting microwaves; and heating the mixed liquid by irradiating the mixed liquid with microwaves, and thereby curing the mixed liquid while foaming. In the foaming step, an inner pressure control member 3 moving while directly or indirectly pressing the surface of the mixed liquid controls the inner pressure of the mixed liquid. The inner pressure of the mixed liquid can be preferably controlled by its own weight of the inner pressure control member 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a foam and a foam manufacturing apparatus.

Background Art

[0002] Foams such as melamine foam are known. The foam is used, for example, as a heat insulating material, a sound absorbing material, or a sponge for washing dishes.

[0003] Patent Document 1 discloses a method for manufacturing melamine foam. In this manufacturing method, the raw material of melamine foam is heated by irradiation with microwaves, and the curing reaction is allowed to proceed while foaming the raw material. Further, in the method for manufacturing melamine foam described in Patent Document 1, the raw material of melamine foam is supplied into a molding die having a predetermined internal contour shape. As the foaming of the raw material progresses, the raw material spreads throughout the inside of the molding die, and as a result, a melamine foam having an external contour shape that matches the internal contour shape of the molding die is obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the manufacturing method described in Patent Document 1, although a foam having a desired outer contour shape can be manufactured, due to the fact that the behavior of the raw material during foaming is not controlled at all, contrary to the description in the specification of Patent Document 1, there is a problem that it is difficult to actually manufacture a foam having excellent homogeneity.

[0006] One of the problems to be solved by the present invention is to provide a method for manufacturing a foam having excellent homogeneity and a foam manufacturing apparatus for manufacturing a foam having excellent homogeneity. [Means for solving the problem]

[0007] A method for manufacturing a foam according to one aspect of the present invention comprises the steps of supplying a mixed liquid containing a resin raw material and a foaming agent into the interior of a microwave-transmitting container, and heating the mixed liquid by irradiating it with microwaves, thereby curing the mixed liquid while causing it to foam, wherein in the foaming step, an internal pressure control member moves while directly or indirectly pressing the surface of the mixed liquid to control the internal pressure of the mixed liquid.

[0008] A method for manufacturing a foam according to one aspect of the present invention comprises the steps of supplying a mixed liquid containing a resin raw material and a foaming agent into the inside of a microwave-transmitting container, and heating the mixed liquid by irradiating it with microwaves, thereby curing the mixed liquid while causing it to foam, wherein in the foaming step, the amount of foaming of the mixed liquid is measured, and the output of the microwaves is controlled according to the amount of foaming.

[0009] A foam manufacturing apparatus according to one aspect of the present invention comprises a container that contains a mixed liquid containing a resin raw material and a foaming agent and is permeable to microwaves; a microwave oscillator that generates microwaves; a microwave irradiation unit that irradiates the mixed liquid with microwaves in order to heat the mixed liquid and cure it while foaming; and an internal pressure control member that controls the internal pressure of the mixed liquid by moving in conjunction with the foaming of the mixed liquid while directly or indirectly pressing the surface of the mixed liquid.

[0010] A foam manufacturing apparatus according to one aspect of the present invention comprises a container for containing a mixed liquid containing a resin raw material and a foaming agent, and which transmits microwaves; a microwave oscillator for generating microwaves; a microwave irradiation unit for irradiating the mixed liquid with microwaves in order to heat the mixed liquid and harden it while foaming; a measuring means for measuring the amount of foaming of the mixed liquid; and a microwave control unit for controlling the output of microwaves according to the amount of foaming. [Effects of the Invention]

[0011] According to the present invention, a foam with excellent homogeneity can be manufactured. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of the configuration of a foam manufacturing apparatus according to an embodiment. [Figure 2] Figure 1 is a block diagram of the foam manufacturing apparatus. [Figure 3] This is a cross-sectional view of the housing shown in Figure 1. [Figure 4] This is a cross-sectional view of the housing shown in Figure 1. [Figure 5] Figure 1 is a cross-sectional view of the container and internal pressure control member shown. [Figure 6] Figure 1 is a plan view of the container and internal pressure control member shown. [Figure 7] This diagram shows the flow of the method for manufacturing the foam according to the embodiment. [Figure 8] This is a diagram illustrating the foaming process. [Figure 9] This is a diagram illustrating the foaming process. [Figure 10] This is a plan view of the enclosure in a modified example. [Figure 11] This is a cross-sectional view illustrating a modified example of a container and an internal pressure control member. [Figure 12] This is a cross-sectional view illustrating a modified example of a container and an internal pressure control member. [Figure 13] This is a cross-sectional view illustrating a modified example of a container and an internal pressure control member. [Figure 14] This is a cross-sectional view illustrating a modified example of a container and an internal pressure control member. [Modes for carrying out the invention]

[0013] Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, the dimensions and scales of each part are appropriately different from the actual ones, and there are also some parts shown schematically for easy understanding. Further, the scope of the present invention is not limited to these forms unless there is a description to specifically limit the present invention in the following description.

[0014] Before explaining the foam manufacturing apparatus according to the embodiment and the method for manufacturing a foam according to the embodiment, first, the foam manufactured by the manufacturing method and the mixed liquid which is its raw material will be explained.

[0015] 1. Foam 0The foam manufactured by the manufacturing method using microwaves described later is a porous body having a plurality of bubbles. The foam is formed of a thermosetting resin such as, for example, urethane resin or melamine resin. Further, the foam may have open cells in which the bubbles are continuous, or may have closed cells in which the bubbles exist independently without being continuous. However, it is preferable that the foam has open cells. Physical property values such as the density, average pore diameter, porosity, and expansion ratio of the foam are not particularly limited respectively. Further, the shape of the foam is not particularly limited, and examples thereof include columnar and flat plate shapes.

[0016] [[ID=[]]] Such a foam is used, for example, as a heat insulating material, a sound absorbing material, a cushioning material, a sealing material, a cushioning material, a sports mat, or a sponge for washing dishes. Note that the use of the foam is not particularly limited and is arbitrary. By adjusting the porosity and the like, the foam can be used for any application.

[0017] 2. Mixed liquid The above-mentioned foam is obtained by irradiating a liquid mixed liquid (hereinafter also simply referred to as "mixed liquid") which is a raw material with microwaves and curing the mixed liquid while foaming it. The mixed liquid contains a main agent containing a resin raw material and a foaming agent. Further, the mixed liquid contains, if necessary, for example, a foaming aid and a curing agent.

[0018] The main component comprises a resin raw material, a surfactant, and additives such as a pH adjuster. Examples of resin raw materials include monomers of thermosetting resins such as urethane or melamine. The resin raw material may also include condensates of melamine or formaldehyde. Examples of foaming agents include fluorine-based unsuitable solvents such as hydrofluorocarbons and water. Examples of foaming aids include alcohol compounds such as methanol or ethanol and hydrocarbons. Examples of curing agents include acidic catalysts such as formic acid.

[0019] The respective content ratios of the main component, foaming agent, foaming aid, and curing agent are not particularly limited and can be arbitrarily set, for example, according to the physical properties of the foam to be manufactured, such as density. In addition, the mixture may contain materials other than the main component, foaming agent, foaming aid, and curing agent. Furthermore, the mixture may be in paste form.

[0020] 3. Foam manufacturing apparatus 100 Figure 1 is a schematic diagram showing an example of the configuration of a foam manufacturing apparatus 100 according to an embodiment. In Figure 1, the X-axis, Y-axis, and Z-axis are shown as three mutually orthogonal axes. The XY plane is parallel to the horizontal plane, and the direction along the Z-axis is parallel to the vertical direction. For the sake of explanation, in the following, one direction along the X-axis will be called the X1 direction, and the direction opposite to the X1 direction will be called the X2 direction. Similarly, one direction along the Y-axis will be called the Y1 direction, and the direction opposite to the Y1 direction will be called the Y2 direction. One direction along the Z-axis will be called the Z1 direction, and the direction opposite to the Z1 direction will be called the Z2 direction. Furthermore, in the following, the Z1 direction will be referred to as "upward" and the Z2 direction as "downward".

[0021] 3-1. Overall configuration of the foam manufacturing apparatus 100 The foam manufacturing apparatus 100 shown in Figure 1 is an apparatus for manufacturing the aforementioned foam. The foam manufacturing apparatus 100 is an apparatus for manufacturing foam from a mixture by heating the mixture by irradiating it with microwaves. By using a microwave heating method, the mixture can be heated more uniformly compared to other heating methods, thereby improving the homogeneity of the foam. For example, by using microwaves, it is possible to reduce the variation in the distribution of bubble percentage within the foam.

[0022] As shown in Figure 1, the foam manufacturing apparatus 100 includes a housing 1, a container 2, an internal pressure control member 3, a transport mechanism 4, a mixed liquid supply unit 5, a position sensor 6, a plurality of microwave irradiation units 7a and 7b, and a control device 8. Note that microwave irradiation units 7a and 7b have the same configuration. When microwave irradiation units 7a and 7b are not distinguished, they will be referred to as microwave irradiation unit 7. Each part will be briefly described below.

[0023] The housing 1 is a box-shaped housing that contains the container 2. The inner wall of the housing 1 is reflective to microwaves, and the housing 1 is configured to prevent microwaves from leaking to the outside. The housing 1 is made of a non-magnetic metal material such as stainless steel, aluminum, or copper. At least the inner wall of the housing 1 needs to be reflective to microwaves, and the housing 1 may include parts that are not reflective to microwaves. The housing 1 may also be provided with an observation window (not shown) for observing the inside.

[0024] In the illustrated example, the external shape of the housing 1 is elongated along the X-axis. An entrance 102 into which the container 2 is loaded is provided at one end of the housing 1 in the longitudinal direction (the end in the X2 direction), and an exit 103 into which the container 2 is unloaded is provided at the other end (the end in the X1 direction). When microwaves are irradiated, the entrance 102 is closed by an opening and closing entrance door 12, and the exit 103 is closed by an opening and closing exit door 13. Note that the external shape of the housing 1 is not limited to elongated along the X-axis; for example, it may be elongated along the Y-axis, or it may have other shapes. Also, the size of the housing 1 is not particularly limited and is determined, for example, according to the distribution of microwaves irradiated inside the housing 1, or the scale of foam production, etc.

[0025] Container 2 is a case that contains the mixed liquid. Container 2 is made of a material and thickness that transmits microwaves. Container 2 is made of, for example, glass or resin. A pressure control member 3 is also placed in container 2 to control the internal pressure of the mixed liquid. The pressure control member 3 is a flat plate-shaped member. The pressure control member 3 may also be in the form of a film. Similar to container 2, the pressure control member 3 is made of a material and thickness that transmits microwaves. The housing 1, container 2, and pressure control member 3 will be described in detail later.

[0026] The conveying mechanism 4 is a mechanism for conveying the container 2. The conveying mechanism 4 mainly conveys the container 2 in the X1 direction, but it may be capable of conveying in both the X1 and X2 directions. In the following, the X1 direction, which is the direction in which the container 2 is conveyed, will also be referred to as the "conveying direction".

[0027] The conveying mechanism 4 has a plurality of conveyors 40, 41, and 42. Conveyor 40 is positioned between conveyor 41 and conveyor 42, and a portion of conveyor 40 is located inside the housing 1. Conveyors 40, 41, and 42 each convey containers 2 in the X1 direction. Containers 2 are conveyed from conveyor 41 to conveyor 40, pass through the housing 1, and then conveyed to conveyor 42. The configuration of conveyors 41 and 42 is not particularly limited, as long as they can convey containers 2 in the X1 direction. Also, one or both of conveyors 41 and 42 may be provided as needed and may be omitted.

[0028] The conveyor 40 includes a plate 45, a drive pulley 401, a driven pulley 402, a belt 403, a plurality of rollers 404, a motor 405, an encoder 406, and a proximity sensor 407. The belt 403 is stretched between the drive pulley 401 and the driven pulley 402. A portion of the belt 403 passes through the housing 1 and supports the plate 45 which is placed inside the housing 1. Of the elements constituting the conveyor 40, the portion of the belt 403 and the plate 45 are located outside the housing 1. The belt 403 is made of a material and thickness that transmits microwaves. The belt 403 is made of, for example, resin. The plate 45 is a component for transporting containers 2, and the containers 2 are placed on the plate 45. The plate 45 is made of a material and thickness that transmits microwaves. The plate 45 is made of, for example, glass or resin.

[0029] The motor 405 is, for example, a DC motor or an AC motor. A drive pulley 401 is connected to the rotating shaft of the motor 405. The driving force generated by the motor 405 is transmitted to the drive pulley 401, causing the belt 403 to move. As the belt 403 moves, the plate 45 moves in the X1 direction or the X2 direction. This movement of the plate 45 causes the container 2 to be transported in the X1 direction or the X2 direction.

[0030] The encoder 406 is, for example, a pulse generator. In the example shown in Figure 1, the encoder 406 is attached to the driven pulley 402. The encoder 406 outputs a signal corresponding to the rotation angle, rotation speed, etc., of the driven pulley 402. Based on this signal, it is possible to detect the direction and amount of movement of the plate 45. The proximity sensor 407 is, for example, a limit switch. The proximity sensor 407 detects the limit position of movement of the plate 45 in the X1 direction and the limit position of movement in the X2 direction.

[0031] The movement of the container 2 by the transport mechanism 4 may be continuous, or it may be discontinuous, combining movement and stopping. For example, the movement of the container 2 by the transport mechanism 4 may be stopped while the container 2 is being irradiated with microwaves. The movement speed of the container 2 by the transport mechanism 4 may be constant, or it may vary. The transport speed may also be controlled to a predetermined speed, for example.

[0032] The mixed liquid supply unit 5 is installed outside the housing 1 and is a device that measures the mixed liquid and supplies the required amount of mixed liquid into the container 2. In the illustrated example, the mixed liquid supply unit 5 is located above the conveyor 41, but it may be located at a location other than above the conveyor 41. The mixed liquid supply unit 5 may also be equipped with a stirrer. The mixed liquid supply unit 5 may also function as a generating unit that mixes various materials in required amounts to produce a mixed liquid.

[0033] The position sensor 6 is installed in the housing 1. In the example shown in Figure 1, the position sensor 6 is mounted in the housing 1 so as to be positioned above the internal pressure control member 3. The position sensor 6 is, for example, a photosensor that uses light such as infrared light. Specifically, the position sensor 6 has a light-emitting element that irradiates light onto the internal pressure control member 3 and a light-receiving element that receives the reflected light reflected by the internal pressure control member 3. Also, if the position sensor 6 is an infrared sensor, the internal pressure control member 3 is reflective to infrared light. The position sensor 6 measures the distance between itself and the internal pressure control member 3 and detects the position (height) of the internal pressure control member 3 in the Z-axis direction based on the measurement result. For example, the position of the internal pressure control member 3 in the Z-axis direction is the height of the internal pressure control member 3 from the bottom surface of the container 2.

[0034] The number of position sensors 6 is not limited to one, but may be multiple. The position sensors 6 do not have to be installed on the top of the housing 1, but may be installed on, for example, the conveyor 40. In this case, for example, the position sensors 6 are covered with a microwave-reflective material so that they are not affected by microwaves. In addition, the position sensors 6 may be sensors other than photosensors, as long as they can detect the position of the internal pressure control member 3 in the Z-axis direction.

[0035] The microwave irradiation unit 7 is installed in the housing 1. The microwave irradiation unit 7 irradiates microwaves into the housing 1. The microwave irradiation units 7a and 7b are spaced apart from each other and arranged side by side along the X-axis. That is, the microwave irradiation units 7 are arranged along the transport direction of the container 2. The microwave irradiation unit 7a is located on the container 2 loading side of the exhaust unit 15 (described later), and the microwave irradiation unit 7b is located on the container 2 unloading side of the exhaust unit 15. The microwave irradiation unit 7a irradiates microwaves diagonally downward to the right in Figure 1, and the microwave irradiation unit 7b irradiates microwaves diagonally downward to the left in Figure 1.

[0036] Figure 2 is a block diagram of the foam manufacturing apparatus 100 shown in Figure 1. As shown in Figure 2, the microwave irradiation unit 7 has a microwave oscillator 71 that generates microwaves. For example, the microwave oscillator 71 is a magnetron, klystron, gyrotron, or semiconductor oscillator. The microwave frequency is not particularly limited, but for example, it is 915 MHz or 2.45 GHz. Although not shown, the microwave irradiation unit 7 also has a transmission unit that transmits the microwaves generated by the microwave oscillator 71 and irradiates the container 2 with microwaves. This transmission unit is, for example, a waveguide or a coaxial cable that transmits microwaves.

[0037] The microwave output is determined according to the scale of the foam manufacturing apparatus 100 and is not particularly limited. However, in this embodiment, the microwave output from the microwave irradiation unit 7a and the microwave output from the microwave irradiation unit 7b are different. Specifically, the microwave irradiation unit 7a is controlled by the control device 8 to have a higher microwave output than the microwave irradiation unit 7b. Furthermore, it is preferable that the microwave frequencies output from the microwave irradiation unit 7a and the microwave frequencies output from the microwave irradiation unit 7b are the same, but they may be different.

[0038] The control device 8 is a computer that controls the operation of the transport mechanism 4 and the output of the microwave irradiation unit 7. Specifically, the control device 8 has a processing unit 81 and a storage device 82. The processing unit 81 is a processor such as a CPU (Central Processing Unit). The storage device 82 is a memory such as a semiconductor memory. The control program P1 is stored in the storage device 82. By executing the control program P1, the processing unit 81 functions as a transport control unit 811, a position calculation unit 813, and a microwave control unit 812.

[0039] The transport control unit 811 controls the operation of the motor 405 of the transport mechanism 4 so that the container 2 is transported along the X-axis. Specifically, the transport control unit 811 controls the operation of the motor 405 so that the position of the plate 45 along the X-axis, calculated based on the information output from the encoder 406 and the information output from the proximity sensor 407, is at a predetermined position.

[0040] The position calculation unit 813 calculates, for example, the amount of change in the position of the internal pressure control member 3 in the Z1 direction per unit time (i.e., the moving speed of the internal pressure control member 3 in the Z1 direction) based on the information output from the position sensor 6. The aforementioned position sensor 6 and position calculation unit 813 are "measuring means" that detect the position of the internal pressure control member 3 in the Z1 direction and measure the amount of change in position per unit time as the amount of foaming per unit time.

[0041] The microwave control unit 812 controls the output of each microwave emitted by the microwave irradiation units 7a and 7b. Specifically, the microwave control unit 812 controls the output of the microwave irradiation unit 7 based on the information output from the position sensor 6. More specifically, the microwave control unit 812 feedback controls the microwave output so that the degree of foaming of the mixed liquid reaches the target value by changing the intensity of the microwaves output from the microwave irradiation unit 7 according to the amount of change in position per unit time. For example, if the movement speed of the internal pressure control member 3 in the Z1 direction is faster than the target speed, the microwave intensity is lowered, and if the movement speed is slower than the target speed, the microwave intensity is increased. By controlling the microwave output based on the information output from the position sensor 6 in this way, physical properties such as the foaming ratio can be matched to or approached the target value.

[0042] Furthermore, the processing unit 81 may, in addition to controlling the microwave output based on the information output from the position sensor 6, or alternatively, control the transport speed or transport direction of the transport mechanism 4. Also, if multiple position sensors 6 are provided, the microwave control unit 812 may control the microwave irradiation unit 7a using one of the multiple position sensors 6 and control the microwave irradiation unit 7b using another position sensor 6.

[0043] The foam manufacturing apparatus 100 with the above configuration may have elements other than the housing 1, container 2, internal pressure control member 3, transport mechanism 4, mixed liquid supply unit 5, position sensor 6, microwave irradiation unit 7a, microwave irradiation unit 7b, and control device 8. For example, the foam manufacturing apparatus 100 may have sensors other than the position sensor 6 that acquire information about the conditions inside the housing 1, such as temperature and humidity. In this case, the driving of the microwave irradiation unit 7a and microwave irradiation unit 7b may be controlled not only by the information output from the position sensor 6, but also by using the information output from the said sensor in combination. Furthermore, the foam manufacturing apparatus 100 may be equipped with a sensor in addition to or instead of the position sensor 6 that acquires information about the pressure in the Z1 direction applied to the internal pressure control member 3 due to the foaming of the mixed liquid. In this case, the driving of the microwave irradiation unit 7a and microwave irradiation unit 7b may be controlled based on the information output from the said sensor, either in combination with or alone, the information output from the position sensor 6. Therefore, the "measuring means" may have a pressure sensor and measure the amount of change in pressure per unit time as the amount of foaming per unit time.

[0044] 3-2. Enclosure 1 Figures 3 and 4 are cross-sectional views of the housing 1 shown in Figure 1, respectively. Figure 3 shows a cross-section of the housing 1 cut along the XZ plane. As shown in Figure 3, the housing 1 has a box-shaped main body 11 that houses the container 2 and an exhaust section 15. The main body 11 is fitted with the aforementioned loading door 12 and loading door 13. Figure 4 shows a cross-section of the housing 1 cut along the YZ plane. As shown in Figure 4, the housing 1 has an intake section 14. The inside of the housing 1 is filled with air, but it may also be filled with nitrogen gas, for example.

[0045] As shown in Figure 4, the intake section 14 is connected to the main body 11. In the illustrated example, the intake section 14 is connected to the Z2 direction (downward vertical side) of the main body 11. The intake section 14 is a long, cylindrical member with its longitudinal direction in the X1 direction. In the example shown in Figure 4, the intake section 14 is positioned in the Y2 direction relative to the main body 11. As shown in Figures 3 and 4, the length of the intake section 14 in the longitudinal direction is approximately equal to the length of the main body 11 in the X1 direction. Two open ends 106a and 106b are provided at both ends of the intake section 14 in the longitudinal direction. The two open ends 106a and 106b introduce outside air into the interior of the intake section 14. The space inside the intake section 14 is in communication with an intake port 104 formed on the lower side of the side wall of the main body 11. The intake port 104 is a long hole with its longitudinal direction in the X1 direction. The length of the air intake port 104 in the X1 direction is approximately equal to the length of the air intake section 14 in the longitudinal direction. A perforated plate 161 is placed in the air intake port 104 to prevent microwave leakage to the outside. The perforated plate 161 is a plate member having a plurality of minute holes and is placed over the entire area of ​​the air intake port 104. The perforated plate 161 is configured to allow air to flow through.

[0046] As shown in Figure 3, the exhaust section 15 is connected to the main body 11. The exhaust section 15 is a cylindrical member that protrudes from the main body 11 in the Z1 direction. When viewed from the Z1 direction, the exhaust section 15 is located between the microwave irradiation section 7a and the microwave irradiation section 7b. As shown in Figure 4, the exhaust section 15 is located in the center of the housing 1 in the Y1 direction. Although not shown, the microwave irradiation sections 7a and 7b are also located in the center of the housing 1 in the Y1 direction. The space inside the exhaust section 15 communicates with an exhaust port 105 formed on the upper surface of the main body 11. The exhaust port 105 is a circular hole. A perforated plate 162 is placed in the exhaust port 105 to prevent microwave leakage to the outside. The perforated plate 162 is a plate member with multiple minute holes and is placed over the entire area of ​​the exhaust port 105. The perforated plate 162 is configured to allow air to flow. An exhaust mechanism having an exhaust fan (not shown) is connected to the exhaust section 15. The exhaust mechanism generates an airflow within the main body 11 from the intake port 104 to the exhaust port 105.

[0047] As described above, the exhaust section 15 and the intake section 14 circulate air along the inner wall surface of the housing 1 from the intake port 104 to the exhaust port 105 through the operation of an exhaust mechanism (not shown). For example, the exhaust mechanism circulates air in the direction indicated by arrow A1 in Figure 4. As a result, vapors such as water generated from the mixed liquid in the container 2 due to foaming can be released to the outside of the housing 1. This prevents the vapors from liquefying on the inner wall of the main body 11. Consequently, it is possible to prevent microwaves from being absorbed by water, etc. Therefore, compared to the case where such exhaust is not performed, it is possible to control the distribution of microwaves irradiated onto the mixed liquid 10a, and it is not necessary to increase the microwave output for manufacturing the foam unnecessarily. As a result, homogeneous foam can be manufactured efficiently.

[0048] Furthermore, as shown in Figure 4, the length T1 of the open end 106a in the Z1 direction is longer than the length T2 of the intake port 104 in the Z1 direction. Similarly, the length of the open end 106b in the Z1 direction is also longer than the length T2. Therefore, the air introduced from the open ends 106a and 106b can be uniformly circulated throughout the entire intake port 104. Consequently, an airflow from the intake port 104 towards the exhaust port 105 can be generated evenly throughout the entire body 11.

[0049] 3-3. Container 2 and internal pressure control member 3 Figure 5 is a cross-sectional view of the container 2 and internal pressure control member 3 shown in Figure 1. Figure 6 is a diagram corresponding to the cross-section along line AA in Figure 5. The container 2 shown in Figures 5 and 6 is a box-shaped case that opens in the Z1 direction. As shown in Figure 5, the mixed liquid 10a is placed in the container 2. The mixed liquid 10a shown in Figure 5 is the raw material for the foamed body described above. In the illustrated example, the length of the container 2 in the X1 direction is longer than the length in the Y1 direction, but the shape of the container 2 is not particularly limited and can be arbitrary. Alternatively, the shape of the container 2 is a longitudinal shape that is long along the conveying direction, but the shape of the container 2 may be a longitudinal shape that is long along a direction different from the conveying direction, for example. Also, for example, the container 2 may be a square when viewed from the Z2 direction.

[0050] As shown in Figure 5, the container 2 has a bottom 21 and a frame-shaped side wall 22. The shape of the bottom 21 when viewed from the Z2 direction is rectangular. The inner surface of the bottom 21, i.e., the bottom surface 211, is a flat surface. The side wall 22 is a wall extending from the bottom 21 in the Z1 direction. The bottom 21 and the side wall 22 may be integrally molded, or the bottom 21 and side wall 22 may be individually molded and bonded to each other. The inner wall surface of the side wall 22 is a flat surface. The inner wall surface of the side wall 22 and the bottom surface 211 do not have to be flat. The thickness of the side wall 22 is constant, but the thickness of a part of the side wall 22 may be thicker than the thickness of other parts.

[0051] As shown in Figure 5, the internal pressure control member 3 is movable inside the container 2. As shown in Figure 6, the planar area of ​​the internal pressure control member 3 as viewed from the Z1 direction, i.e., the planar area in the XY plane, is smaller than the planar area inside the internal pressure control member 3 as viewed from the Z1 direction. Furthermore, the size and arrangement of the internal pressure control member 3 as viewed from the Z1 direction are set so that a gap d1 is formed around the entire circumference of the internal pressure control member 3. Note that the gap d1 may be constant or vary around the entire circumference of the internal pressure control member 3. Also, a part of the internal pressure control member 3 may be in contact with the container 2.

[0052] Thus, the presence of a gap d1 between the internal pressure control member 3 and the container 2 makes it easier for the internal pressure control member 3 to move inside the container 2 compared to the case where there is no gap d1. Furthermore, the presence of the gap d1 allows for efficient discharge of steam such as water generated from the mixed liquid 10a to the outside of the container 2. In other words, the gap d1 functions as a discharge section for releasing steam to the outside of the container 2.

[0053] For example, the internal pressure control member 3 is made of the same material as the material that makes up the container 2. However, the material of the internal pressure control member 3 may be different from the material of the container 2. Also, the thickness of the internal pressure control member 3 may be the same as or different from the thickness of the container 2. The thickness of the internal pressure control member 3 is determined by, for example, the type of foam. The weight of the internal pressure control member 3 can be set according to its thickness. Furthermore, if the density of the internal pressure control member 3 is ρa and the density of the pre-foaming mixed liquid 10a is ρb, the internal pressure control member 3 is set such that ρa < ρb. Due to this density relationship, the internal pressure control member 3 can be made to float on the pre-foaming mixed liquid 10a.

[0054] As shown in Figure 5, the internal pressure control member 3 is in contact with the surface of the mixed liquid 10a. Here, the mixed liquid 10a attempts to expand in the direction of arrow A2 due to foaming. At this time, the internal pressure control member 3 controls the internal pressure of the mixed liquid 10a, that is, the internal pressure of the bubbles generated in the mixed liquid 10a. Specifically, the internal pressure control member 3 applies pressure to the mixed liquid 10a in the direction opposite to arrow A2 due to its own weight. This limits the expansion of the mixed liquid 10a due to foaming. However, the pressure applied by the internal pressure control member 3 is smaller than the pressure generated by the foaming of the mixed liquid 10a. It is smaller than the internal pressure in the direction of arrow A2. Therefore, the internal pressure control member 3 moves in the direction of arrow A2 as the mixed liquid 10a foams while remaining in contact with it. As shown in Figure 5, the internal pressure control member 3 gradually moves in the direction of Z1. As a result, the mixed liquid 10a expands slowly in the direction of Z1 while maintaining a constant internal pressure.

[0055] Here, the internal pressure control member 3 is in uniform contact with the foaming mixture 10a over almost the entire XY plane, and is pressing against it. Therefore, even if the expansion of bubbles in the mixture 10a proceeds locally due to an uneven distribution of microwave electromagnetic fields during foaming, the rapid volume change of the mixture 10a is suppressed by the internal pressure control member 3. As a result, not only can the foaming process and the final shape be controlled to the desired shape, but it is also thought that convection, bubble subdivision due to stress differences in each bubble wall, and agitation of the entire liquid occur during the gradual volume change, and it has been confirmed that the variation in bubble diameter becomes smaller and the bubbles become more homogenized. This effect becomes more pronounced as the foaming of the mixture 10a progresses and the volume of the foam increases. This is because, as the volume of the foam increases, the electromagnetic field distribution inside the mixed liquid 10a becomes more uneven and varied, and if expansion in unintended directions is allowed, it becomes difficult to homogenize the shape and bubbles. However, according to the configuration of the present invention, the overall fluidity of the liquid and bubbles is ensured, so the entire mixed liquid is heated uniformly.

[0056] In contrast, when the mixed liquid 10a is foamed in a container with a fixed lid, as in the conventional method, a large pressure difference occurs in the mixed liquid 10a between the part in contact with the lid and the part that is not in contact with the lid. This pressure difference causes variations in bubble diameter and bubble density.

[0057] Furthermore, the internal pressure control member 3 controls the internal pressure of the bubbles generated in the mixed liquid 10a by its own weight. Therefore, variations in bubble diameter can be suppressed with a simple configuration. The internal pressure control member 3 in this embodiment is made of a flat plate with a uniform thickness. Therefore, compared to the case where a member with an irregular thickness is used, it is easier to apply uniform pressure to the top of the mixed liquid 10a by the weight of the internal pressure control member 3.

[0058] The thickness and constituent materials of the internal pressure control member 3 are determined, for example, by the types of materials contained in the mixed liquid 10a and the respective content ratios of the materials contained in the mixed liquid 10a. In this embodiment, the internal pressure control member 3 controls the internal pressure of the mixed liquid 10a by its own weight, but the internal pressure control member 3 may be biased toward the mixed liquid 10a using an elastic member such as a spring. In this embodiment, the pressure exerted by the internal pressure control member 3 is constant over time, but it may change over time. In addition, the pressure exerted by the internal pressure control member 3 is uniform over the range along the XY plane of the internal pressure control member 3, but it does not have to be uniform. In addition, the thickness of the internal pressure control member 3 is constant, but it does not have to be constant.

[0059] 4. Method for manufacturing foam Figure 7 is a diagram showing the flow of a foam manufacturing method according to the embodiment. As shown in Figure 7, the foam manufacturing method includes a supply step S11 and a foaming step S12. Each step will be described below.

[0060] 4-1. Supply process S11 In the supply process S11, as shown in Figure 5, the mixed liquid 10a is supplied into the container 2. In the supply process S11, for example, with the container 2 positioned on the conveyor 41 shown in Figure 1, a predetermined amount of the mixed liquid 10a is supplied into the container 2 from the mixed liquid supply unit 5. Also, for example, once the supply of the mixed liquid 10a to the container 2 is complete, the internal pressure control member 3 is placed on the mixed liquid 10a from above the container 2 so as to be in contact with the mixed liquid 10a.

[0061] 4-2. Foaming process S12 Figures 8 and 9 are explanatory diagrams of the foaming process S12, respectively. In the foaming process S12, the mixed liquid 10a is heated by irradiating it with microwaves. Due to this heating, the mixed liquid 10a hardens while foaming. The foaming process S12 can also be described as a heating process in which the mixed liquid 10a is heated by microwaves.

[0062] Specifically, as shown in Figure 8, first, the container 2 is transported from conveyor 41 onto conveyor 40. In other words, the container 2 is placed inside the housing 1. When the container 2 is placed inside the housing 1, the loading door 12 of the housing 1 is opened and closed.

[0063] Next, once the container 2 is placed inside the housing 1, the microwave irradiation units 7a and 7b begin irradiating the inside of the housing 1 with microwaves under the control of the microwave control unit 812. Microwave irradiation is performed with the loading door 12 and the unloading door 13 closed. As mentioned above, since the housing 1 is reflective of microwaves, leakage of microwaves to the outside can be prevented.

[0064] When microwaves are irradiated onto the mixture 10a, the mixture 10a is heated. When the mixture 10a is heated, foaming of the mixture 10a begins. Specifically, the heated portion of the mixture 10a vaporizes, generating gas, which causes the mixture 10a to expand from the inside. In addition, a curing reaction begins along with this foaming.

[0065] As mentioned above, in the supply process S11, the internal pressure control member 3 is placed on the mixed liquid 10a. Therefore, at the start of microwave irradiation, the internal pressure control member 3 is in contact with the mixed liquid 10a. However, the internal pressure control member 3 may be positioned inside the container 2 so as to come into contact with the mixed liquid 10a after the start of microwave irradiation. In other words, the internal pressure control member 3 is positioned on the mixed liquid 10a between the supply process S11 and the foaming process S12, or during the foaming process S12.

[0066] Next, once the microwave irradiation by the microwave irradiation units 7a and 7b begins, the conveyor 40 transports the container 2 in the X1 direction under the control of the transport control unit 811. Therefore, the transport of the container 2 and the microwave irradiation of the mixed liquid 10a are performed simultaneously and in parallel. By irradiating the container 2 with microwaves while transporting it, the distribution of microwaves on the mixed liquid 10a can be controlled compared to when the container 2 is not moved while the microwaves are irradiated. As a result, the homogeneity of the foam produced can be improved. Furthermore, by moving the container 2 relative to the housing 1, the configuration of the foam manufacturing apparatus 100 can be simplified compared to a configuration in which the microwave irradiation units 7a and 7b are moved relative to the housing 1.

[0067] The microwave irradiation and the transport of the container 2 by the conveyor 40 may be started simultaneously, or the microwave irradiation may be started after the transport of the container 2 by the conveyor 40 has started. Furthermore, the microwave irradiation units 7a and 7b may start irradiating simultaneously, or, for example, the microwave irradiation unit 7a may irradiate the mixed liquid 10a with microwaves first, and then the microwave irradiation unit 7b may irradiate the mixed liquid 10a with microwaves. The timing of the start of irradiation by the microwave irradiation units 7a and 7b may be determined, for example, according to the transport speed and transport direction of the container 2.

[0068] As the container 2 is transported by the conveyor 40, it moves from a position closer to the loading door 12 than the loading door 13, as shown in Figure 8, to a position closer to the loading door 13 than the loading door 12, as shown in Figure 9. During this movement, the mixed liquid 10a is continuously irradiated with microwaves. As a result, the mixed liquid 10a expands in the Z1 direction, and the curing reaction proceeds. During the foaming and curing reaction, the mixed liquid 10a contains both cured and uncured portions. In this specification, both the state before the start of curing and the state in which cured and uncured portions are mixed will be described as the mixed liquid 10a.

[0069] Furthermore, as mentioned above, the internal pressure control member 3 is placed on the mixed liquid 10a before the container 2 is placed in the housing 1. Therefore, during microwave irradiation, the internal pressure control member 3 is in contact with the mixed liquid 10a. As a result, when the mixed liquid 10a hardens while foaming, the internal pressure control member 3 controls the internal pressure of the bubbles generated in the mixed liquid 10a. Therefore, the mixed liquid 10a expands in the Z1 direction while its expansion due to foaming is limited to predetermined conditions.

[0070] In this way, as the mixture 10a hardens while foaming, the internal pressure control member 3 controls the internal pressure of the mixture 10a. Therefore, during foaming, variations in the pressure applied to the entire circumference of the mixture 10a by the container 2 and the internal pressure control member 3 can be reduced. As a result, differences in the degree of expansion of the generated bubbles can be suppressed. In addition, since the internal pressure control member 3 is movable in conjunction with foaming, variations in bubble diameter due to differences in bubble generation time can be reduced. For these reasons, variations in bubble diameter in the foam can be suppressed.

[0071] In particular, it is preferable that the internal pressure control member 3 controls the internal pressure of the mixed liquid 10a even before the microwave irradiation of the mixed liquid 10a begins. This makes it possible to achieve greater uniformity in the bubble diameter in the foam compared to when the internal pressure of the mixed liquid 10a is controlled after the microwave irradiation has started.

[0072] Furthermore, the internal pressure control member 3 controls the internal pressure of the bubbles generated in the mixed liquid 10a by its own weight during foaming of the mixed liquid 10a. Therefore, in this embodiment, the internal pressure control member 3 is in direct contact with the surface of the mixed liquid 10a and applies pressure. Thus, during foaming of the mixed liquid 10a, the internal pressure control member 3 controls the internal pressure of the mixed liquid 10a by contacting the surface of the mixed liquid 10a and moving while directly pressing the mixed liquid 10a. As in this embodiment, by controlling the internal pressure of the bubbles generated in the mixed liquid 10a by the weight of the internal pressure control member 3, variations in bubble diameter can be suppressed with a simple configuration.

[0073] Furthermore, as mentioned above, the microwave irradiation unit 7a irradiates microwaves diagonally downward to the right in Figure 1, and the microwave irradiation unit 7b irradiates microwaves diagonally downward to the left in Figure 1. Therefore, compared to, for example, the case where microwaves are irradiated from directly above onto the container 2, the microwaves can be effectively irradiated to the central part of the mixed liquid 10a placed inside the container 2.

[0074] Furthermore, as shown in Figure 8, when the container 2 is positioned closer to the loading door 12 than to the loading door 13, the mixed liquid 10a inside the container 2 is more strongly affected by microwaves from the microwave irradiation unit 7a than by microwave irradiation unit 7b. On the other hand, as shown in Figure 9, when the container 2 is positioned closer to the loading door 13 than to the loading door 12, the mixed liquid 10a inside the container 2 is more strongly affected by microwaves from the microwave irradiation unit 7b than by microwave irradiation unit 7a. As mentioned above, the microwave irradiation unit 7a emits microwaves of a stronger intensity than the microwaves emitted from the microwave irradiation unit 7b. Therefore, the intensity of microwaves irradiated onto the mixed liquid 10a in the early stages of manufacturing is stronger than the intensity of microwaves irradiated onto the mixed liquid 10a in the final stages of manufacturing.

[0075] By gradually decreasing the output of the microwaves irradiated onto the mixture 10a, the variation in the distribution of bubbles within the foam can be reduced compared to when the output is not changed over time. Foaming can be accelerated by increasing the microwave output immediately after the start of microwave irradiation of the mixture 10a. Furthermore, after the mixture 10a has foamed to the target foam shape, it is preferable to maintain the temperature of the foam in order to maintain that shape. It is also considered that this change in output is effective even in a configuration without an internal pressure control member 3.

[0076] Next, for example, when it is determined that a preset irradiation time has been reached, the microwave irradiation units 7a and 7b stop irradiating with microwaves under the control of the microwave control unit 812. Through this process, a foam is produced from the mixed liquid 10a. After microwave irradiation, a drying process may be performed as needed.

[0077] Next, once the foam is manufactured, the container 2 is transported from conveyor 40 to conveyor 42. The manufactured foam is then demolded from the container 2 and molded into a predetermined shape by removing unnecessary parts using a cutting machine or the like.

[0078] The method for manufacturing the foam has been described above. For example, when processing multiple containers 2 in succession, when the mixed liquid 10a is supplied to one container 2, the mixed liquid 10a in another container 2 is irradiated with microwaves. Multiple containers 2 may be arranged inside the housing 1, but it is preferable to arrange only one container 2 inside the housing 1 in order to sufficiently improve the homogeneity of the foam. In addition, in the above description, the mixed liquid 10a was irradiated with microwaves while the containers 2 were being transported, but for example, the mixed liquid 10a may be irradiated with microwaves when the transport of the containers 2 is stopped.

[0079] 5. Variations The embodiments illustrated above can be modified in various ways. Specific examples of modifications that can be applied to the aforementioned embodiments are illustrated below. Two or more examples arbitrarily selected from the following examples can be combined as appropriate, to the extent that they do not contradict each other.

[0080] In the embodiment described above, the foam manufacturing apparatus 100 has two microwave irradiation units 7a and 7b, but the number of "microwave irradiation units" may be one or three or more. Figure 10 is a plan view of the housing 1 in a modified example.

[0081] For example, the housing 1 shown in Figure 10 has nine microwave irradiation units 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, and 7i. Microwave irradiation units 7c, 7d, and 7e are arranged in the Y1 direction relative to the housing 1 and spaced apart from each other. Microwave irradiation units 7f, 7g, and 7h are arranged in the Y2 direction relative to the housing 1 and spaced apart from each other. These microwave irradiation units 7c, 7d, 7e, 7f, 7g, and 7h irradiate the mixed liquid 10a placed in the container 2 with microwaves along the Y1 or Y2 direction. The arrangement of the microwave irradiation units 7c, 7d, 7e, 7f, 7g, and 7h in the Z1 direction is not particularly limited, but it is preferable that they be positioned above the container 2. This allows the mixed liquid 10a in the container 2 to be irradiated with microwaves particularly evenly. In addition, microwave irradiation unit 7i is installed so that it can irradiate the mixed liquid 10a in the container 2 with microwaves from below the housing 1. Note that the arrangement of the microwave irradiation units 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, and 7i is not limited to the example shown in Figure 9. Furthermore, only one of these units may be installed in the foam manufacturing apparatus 100.

[0082] In the embodiment described above, the container 2 has an opening that opens in the Z1 direction, but the position of the opening is not limited to this. The container 2 may have an opening that opens in the X1 direction, for example. For example, there is the example shown in Figure 11. Figure 11 is a cross-sectional view illustrating a modified container 2A and an internal pressure control member 3A. The container 2A shown in Figure 11 differs from the container 2 described above in that it has an opening that opens in the X1 direction. Also, the internal pressure control member 3A shown in Figure 11 differs from the internal pressure control member 3 described above in that it moves in the X1 direction as the mixed liquid 10a foams.

[0083] As shown in Figure 11, the internal pressure control member 3A is positioned to close the opening of the container 2A that is open in the X1 direction. However, a space d2 exists between the top of the internal pressure control member 3A and the container 2A. The space d2 is large enough so that the mixed liquid 10a does not flow out of the space d2. A support rod 35 is attached to the internal pressure control member 3A to support it. The support rod 35 is inserted, for example, through a through hole formed in the discharge door 13. By being inserted through the through hole, the support rod 35 is slidably supported by the discharge door 13. The through hole is designed so that microwaves MW do not leak to the outside when the support rod 35 is inserted through it.

[0084] Furthermore, the container 2 may have an opening that is open in the Z2 direction, for example. For example, the example shown in Figure 12 is shown. Figure 12 is a cross-sectional view illustrating the container 2B and the internal pressure control member 3B in a modified example.

[0085] Container 2B shown in Figure 12 differs from container 2 in that it has an opening that opens in the Z2 direction. Also, the internal pressure control member 3B shown in Figure 12 differs from the internal pressure control member 3 in that it is a tray and moves in the Z2 direction as the mixed liquid 10a foams.

[0086] As shown in Figure 12, the internal pressure control member 3B is a tray having a bottom and side walls. The mixed liquid 10a is placed inside the internal pressure control member 3B. The depth of the tray is such that the mixed liquid 10a does not flow out before it hardens. There is also a space d3 between the side walls of the internal pressure control member 3B and the container 2B. The space d3 is such that the mixed liquid 10a does not flow out of it. In addition, a plurality of elastic members 36 are attached to the internal pressure control member 3B to support it. Each elastic member 36 is, for example, a coil spring. One end of each elastic member 36 is connected to the internal pressure control member 3B, and the other end of each elastic member 36 is connected to the plate 45. The plate 45 is, for example, frame-shaped to ensure air circulation into the container 2. The container 2B is detachably connected to the plate 45. As the internal pressure control member 3B foams up, it moves in the Z2 direction against the elastic force of each elastic member 36.

[0087] Thus, the direction in which container 2 is opened is not limited to the Z1 direction as described above, but may be in a direction other than the Z1 direction. However, if the fluidity of the mixed liquid 10a is high, it is preferable to open it in the Z1 direction.

[0088] Furthermore, in the above-described embodiment, the internal pressure control member 3 is flat, but it may also be film-shaped. For example, see the examples shown in Figures 13 and 14. Figures 13 and 14 are cross-sectional views illustrating the container 2C and internal pressure control member 3C in modified examples. The internal pressure control member 3C shown in Figures 12 and 13 is made of film. Multiple rollers 38 are attached to the container 2 to feed the internal pressure control member 3C. Multiple stopper members 37, which function as both rollers and stoppers, are also attached to the container 2. For example, the ends of the internal pressure control member 3C are configured to catch on each stopper member 37. The internal pressure control member 3C is pulled up in the Z1 direction by the foaming of the mixed liquid 10a. At this time, the multiple stopper members 37 and the multiple rollers 38 restrict the internal pressure control member 3C from being fed in the Z1 direction.

[0089] Furthermore, in the above-described embodiment, the internal pressure control member 3 is in direct contact with the surface of the mixed liquid 10a, but it does not have to be in direct contact. The internal pressure control member 3 may apply pressure by directly contacting the surface of the mixed liquid 10a, or it may apply pressure via a gas.

[0090] Although the foam manufacturing apparatus and foam manufacturing method of the present invention have been described above based on the illustrated embodiments, the present invention is not limited to these. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that performs a similar function to that of the above-described embodiments, and any configuration can be added. Each process in the manufacturing method of the present invention can be replaced with any process that performs a similar function to that of the above-described embodiments, and any process can be added. [Explanation of Symbols]

[0091] 1...Housing, 2...Container, 2A...Container, 2B...Container, 3...Internal pressure control member, 3A...Internal pressure control member, 3B...Internal pressure control member, 3C...Internal pressure control member, 4...Transportation mechanism, 5...Mixed liquid supply unit, 6...Position sensor, 7...Microwave irradiation unit, 7a...Microwave irradiation unit, 7b...Microwave irradiation unit, 7c...Microwave irradiation unit, 7d...Microwave irradiation unit, 7e...Microwave irradiation unit, 7f...Microwave irradiation unit, 7g...Microwave irradiation unit, 7h...Microwave irradiation unit, 7i...Microwave irradiation unit, 8...Control device, 10a...Mixed liquid, 11...Main body, 12...Input door, 13...Output door, 14...Intake unit, 15...Exhaust unit, 21...Bottom, 22...Side wall, 35...Support rod, 36...Elastic member, 37...Stopper member, 38...Roller, 40...Conveyor, 4 1...Conveyor, 42...Conveyor, 45...Plate, 71...Microwave oscillator, 81...Processing device, 82...Memory device, 100...Foam manufacturing device, 102...Inlet, 103...Outlet, 104...Intake, 105...Exhaust, 106a...Open end, 106b...Open end, 161...Perforated plate, 162...Perforated plate, 211...Bottom surface, 401...Drive pulley, 402...Driven pulley, 403...Belt, 404...Roller, 405...Motor, 406...Encoder, 407...Proximity sensor, 811...Conveying control unit, 812...Microwave control unit, 813...Position calculation unit, A1...Arrow, A2...Arrow, P1...Control program, S11...Supply process, S12...Foaming process, d1...Gap, d2...Space, d3...Space, T1...Length, T2...Length.

Claims

1. A process of supplying a mixed liquid containing resin raw materials and a foaming agent into the inside of a microwave-transmitting container, The process includes a step of heating the mixture by irradiating it with microwaves, thereby curing the mixture while causing it to foam, In the foaming process, The amount of foaming of the mixture is measured, and the microwave output is controlled according to the amount of foaming. In the foaming process, An internal pressure control member moves while directly or indirectly pressing on the surface of the mixed liquid, controlling the internal pressure of the mixed liquid. A method for manufacturing a foam, characterized by measuring the amount of change in the position of the internal pressure control member as the amount of foaming.

2. A container that contains a mixture of resin raw materials and a foaming agent, and that is permeable to microwaves, A microwave oscillator that generates microwaves, A microwave irradiation unit that irradiates the aforementioned mixture with microwaves in order to heat the mixture and cure it while causing it to foam, A measuring means for measuring the amount of foaming of the aforementioned mixture, The system includes a microwave control unit that controls the output of microwaves according to the amount of foaming, The system further comprises an internal pressure control member that controls the internal pressure of the mixed liquid by moving in conjunction with the foaming of the mixed liquid while directly or indirectly pressing on the surface of the mixed liquid, The measuring means includes a position sensor that detects the position of the internal pressure control member, and measures the amount of change in the position of the internal pressure control member as the amount of foaming. A foam manufacturing apparatus characterized by the following features.

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