JP2009196101A - Urethane foam molded body, its producing method, and magnetic induction foam molding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urethane foam molded body equipped with a magnetic body radially oriented and having aeolotropy, the suitable method of producing the urethane foam molded body, and a magnetic induction foam molding device. <P>SOLUTION: The urethane foam molded body is equipped with a hole part and a magnetic body radially oriented with the hole used as the approximate center. The magnetic induction foam molding device 1 is equipped with a foam mold 4 where an annular cavity 43 is partitioned in the inner part, a core rod magnet part 41 disposed on the axial part of the annular cavity 43, and ring magnet parts 42U, 42D disposed at the peripheral edge part of the annular cavity 43. Foam molding is performed by generating a magnetic line L between the core rod magnet part 41 and the ring magnet parts 42U, 42D. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a urethane foam molded article used as, for example, a sound absorbing material or a vibration absorbing material, a manufacturing method thereof, and a magnetic induction foam molding apparatus suitable for manufacturing a urethane foam molded article.

  Urethane foam moldings are frequently used in various fields such as daily necessities, automobiles, and architectures as cushion materials, sound absorbing materials, vibration absorbing materials, and the like. The urethane foam molded body is usually manufactured by foaming a liquid foamed urethane resin raw material in a foam mold cavity (see, for example, Patent Document 1).

For example, when used as an upper support for supporting the suspension on the vehicle body, the urethane foam molded product requires softness in the vertical direction of the vehicle from the viewpoint of riding comfort and hardness in the horizontal direction from the viewpoint of handling stability. Is done. Moreover, since the urethane foam molding has a large number of cells (bubbles) inside, the thermal conductivity is low. For this reason, when arrange | positioning around an engine, a motor, etc. with a heat_generation | fever, high heat dissipation is requested | required so that a malfunction may not arise by accumulation of heat. Thus, various properties are required for urethane foam moldings depending on the application.
JP 2003-97645 A JP 2007-230544 A

  In general, the characteristics of a urethane foam molded product vary depending on the size, shape, openability, etc. of the cell. However, it is difficult to exhibit different characteristics depending on the direction in one urethane foam molded article only by adjusting the cell size or the like conventionally performed. That is, it is difficult to provide anisotropy. For this reason, according to the required characteristics, the present state is that the shape of the urethane foam molded body is devised, or parts made of other materials are combined with the urethane foam molded body. In this case, depending on the shape, stress concentrates on the portion where the shape is changed during compression, and there is a possibility that a crack or the like may occur. Further, when combining other parts, the manufacturing process becomes complicated and the cost increases.

  On the other hand, Patent Document 2 discloses a urethane foam molded body having a magnetic body oriented in the same direction. According to this urethane foam molded article, the heat dissipation in the orientation direction of the magnetic substance is improved by orienting the magnetic substance having a high thermal conductivity. By the way, when the sound absorption target is a component that generates heat and the urethane foam molded body is integrally disposed so as to surround the entire circumference of the component, it is desirable that heat is radiated quickly over the entire circumference. In other words, it is desirable that heat is transmitted radially centering on a component serving as a heat source. In such a case, the urethane foam molded body in which the magnetic body is linearly oriented in the same direction cannot sufficiently dissipate heat. For example, the periphery of the part may be divided into several sections, and a plurality of urethane foam molded bodies may be arranged for each section, but the practicality is poor.

  This invention is made | formed in view of such a situation, and it makes it a subject to provide the urethane foam molded object which comprises the magnetic body radially oriented and has anisotropy. It is another object of the present invention to provide a suitable manufacturing method and a magnetic induction foam molding apparatus.

  (1) In order to solve the above-mentioned problems, the urethane foam molded article of the present invention is characterized by comprising a hole and a radially oriented magnetic body having the hole as a substantial center ( (Corresponding to claim 1).

  The hole may or may not penetrate from the one end surface to the other end surface of the urethane foam molded article. Moreover, it does not necessarily need to be in the center part of a urethane foam molding. The magnetic body is oriented radially with the hole portion as a center. In other words, the magnetic body is oriented in the diameter increasing direction with the hole portion as a center. Thus, for example, in the axial direction of the hole, rigidity is low due to the characteristics derived from the urethane foam material, whereas in the direction substantially perpendicular to the axial direction of the hole, that is, in the orientation direction of the magnetic body, rigidity is caused by the orientation characteristics of the magnetic body. Is expensive. Similarly, the heat dissipation is low in the axial direction of the hole, whereas the heat dissipation is high in the orientation direction of the magnetic body. Thus, according to the urethane foam molded article of the present invention, different characteristics are manifested in the axial direction of the hole and the orientation direction of the magnetic substance. That is, the urethane foam molded article of the present invention has anisotropy.

  (2) Further, the method for producing a urethane foam molded article of the present invention (hereinafter referred to as “the production method of the present invention” as appropriate) is a foam raw material preparation step for preparing a foam raw material containing a foamed urethane resin raw material and a magnetic material. And a foam molding step of injecting the foaming raw material into a foam-type annular cavity, generating magnetic lines of force radially about the shaft portion of the annular cavity to form a magnetic field, and foam-molding in the magnetic field; , (Corresponding to claim 4).

  In the manufacturing method of the present invention, a foaming mold in which annular cavities are defined is used. Further, in the foam molding process, foam molding is performed in a magnetic field formed radially with the axial portion of the annular cavity as a center. For this reason, according to the method for producing a urethane foam molded article of the present invention, the urethane foam molded article of the present invention in which the magnetic material is oriented radially about the hole (corresponding to the shaft portion of the annular cavity) can be easily obtained. Can get to.

  (3) Further, the magnetic induction foam molding apparatus of the present invention includes a foaming mold in which an annular cavity is defined inside, a core rod magnet portion disposed on a shaft portion of the annular cavity, and a peripheral edge of the annular cavity. A ring magnet portion disposed in the portion, and foaming is performed by generating lines of magnetic force between the core rod magnet portion and the ring magnet portion (corresponding to claim 6).

  In the magnetic induction foam molding apparatus of the present invention, a core rod magnet portion is disposed at the shaft portion of the foam-type annular cavity, and a ring magnet portion is disposed at the peripheral portion. When a line of magnetic force is generated between the core bar magnet part and the ring magnet part, a radial magnetic field is formed with the shaft part as the center. Therefore, according to the magnetic induction foam molding apparatus of the present invention, the above urethane foam molded article of the present invention in which the magnetic material is radially oriented with the hole portion (corresponding to the shaft portion of the annular cavity) as a center is easily manufactured. be able to.

  (4) Preferably, in the configuration of (3), an electromagnet part having a core part made of a ferromagnetic material and a coil part arranged on an outer peripheral surface of the core part, and the core bar magnet part The ring magnet portion is preferably magnetized to have different magnetic poles by the electromagnet portion (corresponding to claim 7).

  By using an electromagnet as the magnetic source, the magnetic field formation can be switched on and off instantaneously. In addition, it is easy to control the strength of the formed magnetic field. For this reason, it is easy to control foam molding. Furthermore, since the direction of the current can be switched instantaneously, the direction of the lines of magnetic force between the core rod magnet part and the ring magnet part can be easily reversed. This will be described later. The core rod magnet portion and the ring magnet portion have opposite magnetic poles. For this reason, it is possible to generate stable lines of magnetic force between the core bar magnet portion and the ring magnet portion, that is, in a radial pattern with the shaft portion as the center.

  (5) Preferably, in the configuration of the above (4), it is better to include a yoke portion connected to the core portion in the electromagnet portion and forming a closed loop magnetic path passing through the annular cavity. 8).

  According to this configuration, the magnetic lines of force form a closed loop in the magnetic circuit including the core part, the core bar magnet part, the annular cavity, the ring magnet part, and the yoke part in the electromagnet part. For this reason, leakage of magnetic field lines is suppressed, and a stable magnetic field can be formed in the annular cavity. In addition, it is easy to control the strength of the magnetic field and the influence on the outside due to leakage of the magnetic field lines is small. Further, since leakage of magnetic field lines is suppressed, there is little waste of magnetic force, and the apparatus itself can be downsized.

  (6) Preferably, in the configuration of the above (4) or (5), the direction of the current flowing through the coil part of the electromagnet part is further switched between the core magnet part and the ring magnet part. It is better to provide a magnetic field switching means for reversing the direction of the magnetic lines of force to be generated (corresponding to claim 9).

  As described above, when an electromagnet is used as the magnetic force source, the direction of the magnetic field lines can be instantaneously switched by switching the direction of the current flowing through the coil portion. That is, by switching the direction of the current flowing through the coil part, the direction of the magnetic lines of force between the core bar magnet part and the ring magnet part can be reversed. When the direction of the magnetic lines of force is reversed during foam molding, the magnetic material in the foam raw material vibrates and becomes easy to disperse. When the dispersibility of the magnetic material is improved, for example, the uneven distribution of the magnetic material in a place where the magnetic flux density is large is reduced. Therefore, according to the present configuration including the magnetic field switching means, it is possible to obtain a urethane foam molded article having a good orientation state with less uneven distribution of the magnetic substance. In addition, according to such a urethane foam molded article, the orientation effect of the magnetic substance can be sufficiently exhibited even if the content of the magnetic substance is relatively small.

  (7) Preferably, in any one of the configurations (3) to (6), the core rod magnet portion and the ring magnet portion are incorporated in the foaming mold, and the annular cavity of the foaming mold It is preferable that the inner peripheral surface is formed by the core rod magnet portion and the outer peripheral surface of the annular cavity is formed by the ring magnet portion (corresponding to claim 10).

  In this configuration, for example, when the core rod magnet portion and the ring magnet portion are each a permanent magnet, the urethane foam molded article of the present invention is easily manufactured without separately providing a magnetic source other than the foaming mold. be able to. In other cases, the urethane foam molded article of the present invention can be easily produced using a known magnetic field generator. For example, continuous production becomes possible by holding the foaming mold in the magnetic field generator for a predetermined time and then moving it sequentially. Moreover, various urethane foam moldings can be manufactured using the same magnetic field generator only by changing the foaming mold. Therefore, versatility is improved.

  Hereinafter, embodiments of the urethane foam molded body, the manufacturing method thereof, and the magnetic induction foam molding apparatus of the present invention will be described. The urethane foam molded article, the manufacturing method thereof, and the magnetic induction foam molding apparatus of the present invention are not limited to the following embodiments, and can be modified by those skilled in the art without departing from the gist of the present invention. The present invention can be implemented in various forms with improvements and the like.

<Urethane foam molding>
As described above, the urethane foam molded article of the present invention includes a hole and a radially oriented magnetic body having the hole as a substantial center. The shape of the internal space of the hole is not particularly limited. For example, a desired shape such as a cylindrical shape or a prismatic shape may be used. Moreover, it is good also as a bottomed shape. Further, it may be tapered.

The magnetic body is not particularly limited as long as it is a so-called magnetic material. For example, ferromagnetic materials such as iron, nickel, cobalt, gadolinium, and stainless steel, antiferromagnetic materials such as MnO, Cr ₂ O ₃ , FeCl ₂ , and MnAs, and alloys using them are suitable. For example, when it is desired to improve the heat dissipation of the urethane foam molded article, stainless steel, copper iron alloy and the like are suitable. Here, stainless steel is excellent in rust prevention performance and has high bonding strength with polyurethane foam. Further, the copper iron alloy is a eutectic alloy of copper and iron, and for example, a semi-hard magnetic copper iron alloy as described in Japanese Patent Publication No. 3-064583 is desirable. Such a copper-iron alloy does not cause separation of copper and iron even when finely pulverized. For this reason, it has the two characteristics of the high thermal conductivity which copper has, and the magnetism which iron has. Therefore, even if it is the same content, the higher heat dissipation effect can be acquired compared with another magnetic body.

  The size, shape, etc. of the magnetic material are not particularly limited. For example, it may be a nano-sized particle constituting a magnetic fluid (MF) or a micron-sized particle constituting a magnetorheological fluid (MR fluid). Also, magnetic fillers having various shapes such as spherical, elliptical, oval (a shape in which a pair of opposing hemispheres are connected by a cylinder), water droplets, columns, thin plates, foils, fibers, needles, etc. There may be. The size (maximum length) of the magnetic filler may be determined in consideration of the dispersibility, the orientation, the size of the urethane foam molding to be produced, and the like. For example, a material having a size of 0.1 mm or more and 5 mm or less is preferable because it is easily available.

  For example, when the magnetic filler has a shape other than a sphere, the oriented magnetic fillers are in contact with at least one of a line and a surface, not a point. For this reason, compared with the case where it contacts by a point, the contact area of magnetic fillers becomes large. As a result, a heat transfer path is easily secured and the amount of heat transferred is increased. In addition, the effect of improving the strength is great. Further, the magnetic filler itself has anisotropy and becomes bulky in the orientation direction as compared with the case where the same amount of spherical magnetic filler is blended. Therefore, it is easy to obtain an orientation effect even in a small amount.

When a magnetic filler having a shape other than a sphere is employed, the aspect ratio of the magnetic filler is preferably 2 or more from the viewpoint of increasing heat transferability. In this specification, the aspect ratio is defined by the following equation (1).
Aspect ratio = b ² / (a · a ′) Expression (1)
In the formula (1), b represents the maximum length of the magnetic filler, a represents the length of the transverse side cross-section lateral side, and a ′ represents the length of the longitudinal axis longitudinal section. Here, “the length of the transverse side in the direction perpendicular to the axis” and “the length of the longitudinal side in the direction perpendicular to the axis” are determined as follows. That is, with the maximum length b of the magnetic filler as an axis, a quadrangle in which a cross-sectional shape in a direction perpendicular to the axis (axial direction) is inscribed is defined, and the lateral length when the quadrangle is viewed in plan is expressed as “axis The length “a” of the horizontal side of the cross section in the perpendicular direction is referred to as “the length a ′ of the vertical side of the cross section in the axial direction”. Hereinafter, specific shapes will be described.

  FIG. 1 shows the maximum length, the length of the transverse axis cross-section side length, and the length of the longitudinal axis longitudinal section in each shape of the magnetic filler. In FIG. 1, (a) shows the case of a cylindrical shape, (b) shows the case of a thin plate, and (c) shows the case of a fiber. In addition, the shape shown to Fig.1 (a)-(c) is only an illustration, and a magnetic filler is not limited to these shapes. First, in the case of the columnar shape shown in (a), the length in the axial direction is the maximum length b. The cross-sectional shape in the direction perpendicular to the axis is a circle. The length in the horizontal direction of the quadrangle inscribed by the circle is “the length a ′ of the transverse side in the axial direction”, and the length in the longitudinal direction is “the length a ′ of the longitudinal side in the axial direction”. Next, in the case of the thin plate shape shown in (b), the longitudinal direction is the axial direction, and the length in the longitudinal direction is the maximum length b. Since the cross-sectional shape in the direction perpendicular to the axis is a rectangle, the length in the horizontal direction of this rectangle is “the length a of the transverse side in the direction perpendicular to the axis”, and the length in the vertical direction (corresponding to the thickness) is “direction perpendicular to the axis” The length of the vertical side of the cross section is a '". Next, in the case of the fibrous form shown in (c), the length in the axial direction is the maximum length b. The cross-sectional shape in the direction perpendicular to the axis is substantially an ellipse. However, in the case of the fibrous form (c), it has a shape like an “elongated barrel” having a large central portion in the longitudinal direction and small end portions. For this reason, in the full length in the longitudinal direction, the size of the cross section in the axial direction is not constant. That is, the cross-sectional area of the ellipse is different between the position α, the position β, and the position γ. In this case, the lateral length of the quadrilateral inscribed by the ellipse at the position β where the cross-sectional area is maximum is “the length a of the transverse side of the axial direction”, and the longitudinal length is “the longitudinal section of the axial direction”. The length of the vertical side a ′ ”.

  What is necessary is just to determine suitably the compounding quantity of a magnetic body so that a desired characteristic may be acquired. For example, in order to express the effect of improving heat transfer, it is desirable that the blending amount of the magnetic material is 0.1% by volume or more when the volume of the urethane foam molded body is 100% by volume. It is more suitable when it is 1 volume% or more. On the other hand, in consideration of the influence on the dispersibility and sound absorption characteristics of the magnetic material, the blending amount of the magnetic material is preferably 10% by volume or less. Moreover, when the compounding quantity of a magnetic body exceeds 10 volume%, it will have a bad influence on foam molding and it will become difficult to obtain a favorable urethane foam molded object. Therefore, it is more preferable that the blending amount of the magnetic material is 3% by volume or less.

  According to the urethane foam molded article of the present invention, since the magnetic body is oriented radially with the hole as a center, the characteristics expressed in the axial direction of the hole and the orientation direction of the magnetic body are different. For example, it is desirable from the load-displacement curve in the urethane foam molded article of the present invention that the static spring constant in the orientation direction of the magnetic body is at least twice the static spring constant in the axial direction of the hole. It is more preferable that it is 4 times or more. Note that the static spring constant in the present invention is obtained by cutting a cube having one side of the axial direction of the hole from a urethane foam molded body as a sample, and the load when the sample is compressed 10% in each direction by the amount of displacement. The value calculated by dividing.

  By the way, if foaming urethane resin raw material is foam-molded in a sealed foaming mold, the foamed urethane resin raw material comes into contact with the mold surface of the foaming mold, and foaming is suppressed, thereby forming a high-density skin layer. The thickness of the skin layer is not particularly limited, but may be, for example, 20 μm or less. The presence / absence, thickness, etc. of the skin layer may be adjusted by the filling amount of the foaming raw material into the foaming mold, foaming time, foaming temperature, and the like. Next, the suitable manufacturing method of the urethane foam molding of this invention is explained in full detail.

<Method for producing urethane foam molding>
The manufacturing method of the urethane foam molding of this invention has a foaming raw material preparation process and a foam molding process. Hereinafter, each step will be described.

(1) Foaming raw material preparation process This process is a process of preparing the foaming raw material containing a foaming urethane resin raw material and a magnetic body. The foamed urethane resin raw material may be prepared from already known raw materials such as a polyisocyanate component and a polyol component. Examples of the polyisocyanate component include tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, naphthalene diisocyanate, and derivatives thereof (for example, obtained by reaction with polyols). May be appropriately selected from among prepolymers, modified polyisocyanates and the like. Polyol components include polyhydric hydroxy compounds, polyether polyols, polyester polyols, polymer polyols, polyether polyamines, polyester polyamines, alkylene polyols, urea-dispersed polyols, melamine-modified polyols, and polycarbonate polyols. It may be appropriately selected from the group of polymers, acrylic polyols, polybutadiene polyols, phenol-modified polyols and the like.

Furthermore, you may mix | blend a catalyst, a foaming agent, a foam stabilizer, a crosslinking agent, a flame retardant, an antistatic agent, a viscosity reducing agent, a stabilizer, a filler, a coloring agent, etc. suitably. For example, examples of the catalyst include amine-based catalysts such as tetraethylenediamine, triethylenediamine, and dimethylethanolamine, and organometallic catalysts such as tin laurate and tin octoate. Moreover, water is suitable as the foaming agent. In addition to water, methylene chloride, chlorofluorocarbon, CO ₂ gas and the like can be mentioned. Moreover, a silicone type foam stabilizer is suitable as the foam stabilizer, and triethanolamine, diethanolamine and the like are suitable as the crosslinking agent.

  The following modes can be adopted as the foaming raw material containing the foamed urethane resin raw material and the magnetic material. For example, when the magnetic filler described above is used as the magnetic body, the foaming raw material may be a mixed material obtained by mixing a foamed urethane resin raw material and a magnetic filler. In addition, since it is as having mentioned above about the kind, shape, aspect ratio, compounding quantity, etc. of a magnetic filler, description is abbreviate | omitted here. Or it is good also considering the foaming raw material as the mixed material which mixed the foaming urethane resin raw material and the magnetic body containing fluid. Here, the “magnetic substance-containing fluid” broadly means “a fluid in which fine particles of a magnetic substance are dispersed in a solvent”. Accordingly, the “magnetic substance-containing fluid” includes MR fluid containing micron-sized magnetic particles, MF containing nano-sized magnetic particles, and magnetic mixed fluid (Magnetic) in which MF is mixed with micron-sized magnetic particles. compound fluid (MCF) and the like. Here, the magnetic mixed fluid (MCF) is, for example, a particle-dispersed mixed functional fluid described in Japanese Patent Application Laid-Open No. 2002-170791. The foaming raw material prepared in this step is immediately subjected to the next foam molding step.

(2) Foam molding step In this step, the foam raw material prepared in the foam raw material preparation step is injected into a foam-type annular cavity, and magnetic lines of force are generated radially about the axial portion of the annular cavity. This is a step of forming a magnetic field and foam-molding in the magnetic field. In this step, a foaming mold having an annular cavity defined therein is used. The shape of the annular cavity may be appropriately determined according to the shape of the urethane foam molded article.

  Foam molding is performed by forming a magnetic field radially with the axial portion of the annular cavity as a center. For example, a core rod magnet portion and a ring magnet portion having magnetic poles opposite to each other are used, the core rod magnet portion is disposed on the shaft portion of the annular cavity, and the ring magnet portion is disposed on the peripheral edge portion of the annular cavity. Magnetic field lines can be generated to form a magnetic field.

  The direction of the magnetic lines of force may be a direction from the shaft portion of the annular cavity toward the peripheral portion, or may be a direction from the peripheral portion toward the shaft portion. Further, the direction of the lines of magnetic force may be constant or reversed while the magnetic field is applied. If foam molding is performed with the direction of magnetic lines of force kept constant, the magnetic material may be unevenly distributed due to a difference in the magnetic flux density. This can be solved, for example, by increasing the blending amount of the magnetic material. However, the increase in the blending amount of the magnetic material increases the influence on foam molding. As a result, the inherent characteristics such as sound absorption characteristics, heat insulating properties, and cushioning properties may be deteriorated. In addition, the weight of the urethane foam molding increases and the manufacturing cost also increases. On the other hand, when foam molding is performed while reversing the direction of the lines of magnetic force, the magnetic body vibrates and is easily dispersed. Thereby, the uneven distribution of the magnetic body in a place where the magnetic flux density is large can be reduced. Therefore, it is desirable to perform foam molding while reversing the direction of the lines of magnetic force before the foaming raw material is solidified. In addition, by increasing or decreasing the magnetic field strength, it is possible to suppress the uneven distribution of the magnetic material, as in the case where the direction of the lines of magnetic force is reversed. Therefore, it is only necessary to appropriately select whether to reverse the direction of the lines of magnetic force, increase or decrease the magnetic field strength, or both at the same time as necessary.

  The magnetic field is desirably applied while the viscosity of the foaming material is relatively low. If a foaming raw material is thickened and a magnetic field is applied when foam molding is completed to some extent, the magnetic material is difficult to orient because the thickened foaming raw material prevents the magnetic material from moving. Note that it is not necessary to apply a magnetic field over the entire period of foam molding.

<Magnetic induction foam molding equipment>
(1) First Embodiment Hereinafter, a first embodiment of the magnetic induction foam molding apparatus of the present invention will be described. First, the configuration of the magnetic induction foam molding apparatus of this embodiment will be described. FIG. 2 shows a perspective view of the magnetic induction foam molding apparatus. FIG. 3 shows a partial cross-sectional view of the magnetic induction foam molding apparatus. As shown in FIGS. 2 and 3, the magnetic induction foam molding apparatus 1 includes a pair of electromagnet parts 2 </ b> U and 2 </ b> D, a yoke part 3, a foaming mold 4, and an AC power supply device 5. The AC power supply device 5 includes a function generator (general-purpose oscillator) and a bipolar (positive / negative bipolar output) power supply. The AC power supply device 5 is included in the magnetic field switching means in the present invention.

  The electromagnet part 2U includes a core part 20U and a coil part 21U. The core portion 20U is made of a ferromagnetic material and has a cylindrical shape extending in the vertical direction. The coil portion 21U is disposed on the outer peripheral surface of the core portion 20U. The coil portion 21U is formed by a conducting wire 210U wound around the outer peripheral surface of the core portion 20U. The conducting wire 210U is connected to the AC power supply device 5. The magnitude and direction of the current flowing through the conducting wire 210U are controlled by the AC power supply device 5.

  The electromagnet portion 2D is disposed below the electromagnet portion 2U with the foaming mold 4 interposed therebetween. The electromagnet part 2D has the same configuration as the electromagnet part 2U. That is, the electromagnet part 2D includes a core part 20D and a coil part 21D. The coil portion 21D is formed by a conducting wire 210D wound around the outer peripheral surface of the core portion 20D. Conductive wire 210 </ b> D is connected to AC power supply device 5. The magnitude and direction of the current flowing through the conducting wire 210 </ b> D are controlled by the AC power supply device 5.

  The yoke part 3 is made of a ferromagnetic material and has a C-shape. The C-shaped upper end of the yoke part 3 is connected to the upper end of the core part 20U of the electromagnet part 2U. On the other hand, the C-shaped lower end of the yoke part 3 is connected to the lower end of the core part 20D of the electromagnet part 2D.

  The foaming mold 4 includes an upper mold 40U and a lower mold 40D. The foaming mold 4 is interposed between the core part 20U of the electromagnet part 2U and the core part 20D of the electromagnet part 2D. Hereinafter, the foaming mold 4 will be described in detail. FIG. 4 is an exploded perspective sectional view of the foaming mold. FIG. 5 shows a perspective sectional view of the foaming mold.

  As shown in FIGS. 4 and 5, the lower mold 40D is made of aluminum and has a prismatic shape. A recess having a circular cross section is formed on the upper surface of the lower mold 40D. The lower mold 40D includes a core bar magnet part 41 and a ring magnet part 42D. The core bar magnet part 41 is arranged at the center of the recess. The core bar magnet part 41 is made of the same ferromagnetic material as the core part 20D of the electromagnet part 2D, and has a cylindrical shape. The core bar magnet portion 41 penetrates the bottom surface of the recess and is exposed on the lower surface of the lower mold 40D. The lower bottom surface of the core bar magnet part 41 is in contact with the core part 20D of the electromagnet part 2D. The ring magnet portion 42D is disposed along the outer peripheral edge of the recess. The ring magnet part 42D is made of the same ferromagnetic material as the core part 20U of the electromagnet part 2U, and has a cylindrical shape. The upper end surface of the ring magnet portion 42D is exposed on the upper surface of the lower mold 40D.

  The upper mold 40U is made of aluminum and has a prismatic shape. The upper mold 40U includes a ring magnet portion 42U. The ring magnet portion 42U is embedded in the upper die 40U so as to face the ring magnet portion 42D of the lower die 40D. The ring magnet part 42U is made of the same ferromagnetic material as the core part 20U of the electromagnet part 2U, and has a cylindrical shape. The upper end surface of the ring magnet portion 42U is exposed on the upper surface of the upper mold 40U. The upper end surface of the ring magnet part 42U is in contact with the core part 20U of the electromagnet part 2U. The lower end surface of the ring magnet portion 42U is exposed on the lower surface of the upper mold 40U.

  The upper die 40U and the lower die 40D are arranged so that the lower end surface of the ring magnet portion 42U and the upper end surface of the ring magnet portion 42D are in contact with each other. An annular cavity 43 is defined between the upper mold 40U and the lower mold 40D by sealing the opening of the recess of the lower mold 40D with the lower surface of the upper mold 40U. That is, the annular cavity 43 is partitioned by the lower surface of the upper die 40U, the outer peripheral surface of the core bar magnet portion 41, the inner peripheral surface of the ring magnet portion 42D, and the bottom surface of the concave portion of the lower die 40D. The annular cavity 43 is filled with a predetermined foaming raw material.

  Next, the movement of the magnetic induction foam molding apparatus of this embodiment will be described. When the AC power supply device 5 is turned on, the upper end of the core portion 20U of the electromagnet portion 2U is magnetized to the N pole and the lower end is magnetized to the S pole. For this reason, a magnetic force line L (indicated by a dotted line in FIG. 3) is generated in the core portion 20U from below to above. Further, the upper end of the core portion 20D of the electromagnet portion 2D is magnetized to the N pole and the lower end is magnetized to the S pole. For this reason, lines of magnetic force L are generated in the core portion 20D from below to above. That is, the magnetic poles of the opposing surfaces (the lower surface of the core portion 20U and the upper surface of the core portion 20D) of the electromagnet portions 2U and 2D are different from each other. Here, the core portion 20U and the ring magnet portions 42U and 42D are made of the same ferromagnetic material. Therefore, the ring magnet portions 42U and 42D are both magnetized by the core portion 20U. That is, since the lower end of the core part 20U is the south pole, the ring magnet part 42D is magnetized to the south pole. The core portion 20D and the core rod magnet portion 41 are made of the same ferromagnetic material. Therefore, the core bar magnet part 41 is magnetized by the core part 20D. That is, since the upper end of the core part 20D is an N pole, the core bar magnet part 41 is magnetized to the N pole. Thereby, a magnetic force line L is generated from the core rod magnet part 41 toward the ring magnet part 42D.

  Here, the direction of the lines of magnetic force L in the annular cavity 43 will be described with reference to the drawings. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. The inner peripheral surface of the annular cavity 43 is formed by a core bar magnet portion 41, and the outer peripheral surface is formed by a ring magnet portion 42D. As described above, the core rod magnet portion 41 is magnetized to the N pole, and the ring magnet portion 42D is magnetized to the S pole. Therefore, as indicated by a dotted line in FIG. 6, a magnetic force line L is generated in the annular cavity 43 from the core rod magnet portion 41 toward the ring magnet portion 42 </ b> D. That is, magnetic lines of force L are generated radially in the annular cavity 43 from the center toward the radially outer side. Along the magnetic field lines L, the magnetic body in the foaming raw material is oriented.

  The lines of magnetic force L radiated from the upper end of the core part 20U of the electromagnet part 2U through the ring magnet parts 42D and 42U flow into the lower end of the core part 20D of the electromagnet part 2D through the yoke part 3. That is, in the magnetic circuit composed of the core part 20U → the yoke part 3 → the core part 20D → the core bar magnet part 41 → the annular cavity 43 → the ring magnet part 42D → the ring magnet part 42U, the magnetic lines of force L form a closed loop. .

  On the other hand, when the direction of the current flowing through the conducting wires 210U and 210D is reversed by the AC power supply device 5, each member is magnetized to the opposite magnetic pole. Thereby, for example, the ring magnet portions 42U and 42D are magnetized to the N pole. Moreover, the core bar magnet part 41 is magnetized by the south pole. Therefore, in this case, the lines of magnetic force L are generated from the ring magnet portion 42 </ b> D toward the core rod magnet portion 41. That is, the direction of the lines of magnetic force between the core bar magnet part 41 and the ring magnet part 42D is reversed, and a line of magnetic force L is generated in the annular cavity 43 toward the radially inner side.

  Next, the effect of the magnetic induction foam molding apparatus of this embodiment is demonstrated. According to the present embodiment, the core rod magnet portion 41 and the ring magnet portion 42D that partition the annular cavity 43 can generate stable magnetic lines of force L in the annular cavity 43 in a radial pattern with the axial portion as a center. it can. Therefore, it is possible to easily manufacture a urethane foam molded body in which the magnetic body is oriented radially with the hole portion formed with the core rod magnet portion 41 as the mold surface substantially at the center.

  In the present embodiment, the core rod magnet part 41 and the ring magnet parts 42 </ b> D and 42 </ b> U are incorporated in the foaming mold 4. For this reason, a well-known thing can be utilized for magnetic field generator itself, and versatility is high. Moreover, various urethane foam moldings can be manufactured by changing the configuration of the foaming mold 4 using the same magnetic field generator.

  Further, according to the present embodiment, the function generator (general-purpose oscillator) constituting the AC power supply device 5 can input an electric signal with an arbitrary waveform to each of the electromagnet units 2U and 2D. Thereby, on / off of magnetic field formation can be switched instantaneously. In addition, it is easy to control the strength of the formed magnetic field. Furthermore, the direction of the current can be switched instantaneously, and the direction of the magnetic lines of force between the core bar magnet part 41 and the ring magnet part 42D can be easily reversed. As a result, the behavior of the magnetic material during foam molding can be effectively controlled. For example, if foam molding is performed while reversing the direction of the lines of magnetic force between the core bar magnet part 41 and the ring magnet part 42D, the magnetic body vibrates and is easily dispersed. Therefore, the uneven distribution of the magnetic material is reduced.

  Further, the lines of magnetic force L form a closed loop. For this reason, leakage of the lines of magnetic force L can be suppressed, and a stable magnetic field can be formed in the annular cavity 43. In addition, there is little influence on the outside due to leakage of the lines of magnetic force L. Further, there is little wasted magnetic force, and the device itself can be downsized.

(2) Second Embodiment Next, a second embodiment of the magnetic induction foam molding apparatus of the present invention will be described. The difference between this embodiment and the first embodiment is that four electromagnet portions are juxtaposed mainly on both sides of the foaming mold. Therefore, here, the difference will be mainly described.

  First, the configuration of the magnetic induction foam molding apparatus of this embodiment will be described. In FIG. 7, the perspective view of the magnetic induction foam molding apparatus of this embodiment is shown. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. In FIGS. 7 and 8, members corresponding to those in FIGS. 2 and 3 are denoted by the same reference numerals. As shown in FIGS. 7 and 8, the magnetic induction foam molding apparatus 1 includes four electromagnet parts 2a to 2d, a pair of yoke parts 3U and 3D, a pair of pole pieces 30U and 30D, a foaming mold 4, It has.

  Each of the pair of yoke portions 3U and 3D is made of a ferromagnetic material and has a rectangular plate shape. The pair of yoke portions 3U and 3D are arranged apart from each other by a predetermined interval in the vertical direction. The four electromagnet portions 2a to 2d each have the same configuration as the electromagnet portions 2U and 2D of the first embodiment. That is, each of the four electromagnet portions 2a to 2d includes a core portion and a coil portion disposed on the outer peripheral surface thereof. The coil part is formed of a conducting wire wound around the outer peripheral surface of the core part. Each of the conducting wires is connected to an AC power supply device (not shown). The four electromagnet portions 2a to 2d are interposed between the pair of yoke portions 3U and 3D. Specifically, the four electromagnet portions 2a to 2d are disposed at the four corners of the pair of yoke portions 3U and 3D. The four electromagnet portions 2a to 2d arranged at the four corners respectively connect the pair of yoke portions 3U and 3D like columns.

  Each of the pair of pole pieces 30U and 30D is made of a ferromagnetic material and has a rectangular thin plate shape. The pair of pole pieces 30U and 30D are mounted on the inner surfaces of the pair of yoke portions 3U and 3D, respectively. Further, the pair of pole pieces 30U and 30D are disposed on the inner side of the four electromagnet portions 2a to 2d.

  The foaming mold 4 is interposed between a pair of pole pieces 30U and 30D. The foaming mold 4 includes an upper mold 40U and a lower mold 40D. A pair of guided portions 44 project from the upper edges of both side surfaces of the lower mold 40D. The guided portion 44 extends in the horizontal direction. The pair of guided portions 44 are mounted on a pair of guide portions 60 of a conveyor (not shown). The foaming mold 4 is conveyed by the movement of the pair of guide portions 60.

  A recess having a circular cross section is formed on the upper surface of the lower mold 40D. In the center of the recess, the core bar magnet part 41 penetrates in the vertical direction. The core bar magnet part 41 is exposed on the lower surface of the lower mold 40D. A ring magnet portion 42D is embedded along the outer peripheral edge of the recess. The upper end surface of the ring magnet portion 42D is exposed on the upper surface of the lower mold 40D.

  The upper mold 40U is disposed above the lower mold 40D. A ring magnet portion 42U is embedded in the upper mold 40U. The ring magnet part 42U of the upper mold 40U and the ring magnet part 42D of the lower mold 40D are opposed to each other in the vertical direction. The upper end surface of the ring magnet portion 42U is exposed on the upper surface of the upper mold 40U. The lower end surface of the ring magnet portion 42U is exposed on the lower surface of the upper mold 40U. The pair of ring magnet portions 42U and 42D are connected by clamping. An annular cavity 43 is defined by the lower surface of the upper die 40U, the outer peripheral surface of the core bar magnet portion 41, the inner peripheral surface of the ring magnet portion 42D, and the bottom surface of the concave portion of the lower die 40D.

  Next, the movement of the magnetic induction foam molding apparatus of this embodiment will be described. When the AC power supply is turned on, the upper ends of the core portions of the four electromagnet portions 2a to 2d are magnetized to the N pole and the lower ends are magnetized to the S pole. For this reason, a magnetic force line L (indicated by a dotted line in FIG. 8) is generated in the core portion from below to above. Thereby, between the four electromagnet parts 2a-2d and the foaming mold 4, the electromagnet parts 2a-2d → the upper yoke part 3U → the upper pole piece 30U → the foaming mold 4 → the lower pole piece 30D → A closed loop magnetic path is formed by a path of the lower yoke portion 3D → the electromagnet portions 2a to 2d. In the foaming mold 4, the core rod magnet part 41 is magnetized to the south pole, and the ring magnet part 42D is magnetized to the north pole. Therefore, a magnetic force line L is generated in the annular cavity 43 from the ring magnet portion 42 </ b> D toward the core rod magnet portion 41. That is, the magnetic lines of force L are generated radially in the annular cavity 43 from the radially outer side toward the center. Along the magnetic field lines L, the magnetic body in the foaming raw material is oriented.

  Next, the effect of the magnetic induction foam molding apparatus of this embodiment is demonstrated. The magnetic induction foam molding apparatus of the present embodiment has the same functions and effects as those of the magnetic induction foam molding apparatus of the first embodiment with respect to parts having the same configuration. In the present embodiment, the four electromagnet portions 2a to 2d are juxtaposed, and the lines of magnetic force enter the annular cavity 43 (between the core rod magnet portion 41 and the ring magnet portion 42D) via the pair of yoke portions 3U and 3D. L was generated. For this reason, it is easy to increase the magnetic flux density in the annular cavity 43. Further, the lines of magnetic force L generated from each of the electromagnet portions 2 a to 2 d form a closed loop magnetic path passing through the annular cavity 43. For this reason, leakage of the lines of magnetic force L can be suppressed, and a stable magnetic field can be formed in the annular cavity 43. Moreover, according to this embodiment, the foaming mold 4 can be moved sequentially using a conveyor. For this reason, the urethane foam molding of this invention can be manufactured continuously. Therefore, this embodiment is suitable for mass production.

(3) Others The embodiment of the magnetic induction foam molding apparatus of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. For example, a permanent magnet may be used as the magnetic field generating means instead of an electromagnet. Even when an electromagnet is used, the yoke portion may not be provided. Moreover, in said 1st embodiment, a pair of electromagnet part was arrange | positioned facing the predetermined spacing in the axial direction. On the other hand, in the second embodiment, four electromagnet portions are arranged in parallel on both sides of the foaming mold. As described above, the number and arrangement of the electromagnet portions may be appropriately determined so that a desired magnetic field is formed between the core rod magnet portion and the ring magnet portion. Further, in both the first embodiment and the second embodiment, the core portion of the electromagnet portion has a cylindrical shape extending in the vertical direction. However, the shape of the core is not limited to the above embodiment, and various shapes such as a prismatic shape can be adopted.

  Moreover, it is not necessary to use an AC power supply device (magnetic field switching means). That is, it is not necessary to switch the direction of the current or change the magnetic field strength during foam molding. The magnetic field switching means is not limited to the AC power supply device, and may be constituted by a DC power supply device, a switch that switches the DC power supply device and its current direction, or the like.

  In the above embodiment, the core rod magnet portion and the ring magnet portion are incorporated in the foaming mold. However, the core rod magnet part and the ring magnet part may be arranged separately from the foam type. Moreover, what is necessary is just to determine suitably the magnitude | size, shape, etc. of an annular cavity and a core bar magnet part according to the target urethane foam molded object. In addition, for the reason that the magnetic field generated from a magnetic source such as an electromagnet has little influence and the magnetic field can be easily controlled, it is desirable that the foaming mold is manufactured from a material having a low magnetic permeability, that is, a nonmagnetic material. As the material of the foaming mold, aluminum alloy, nonmagnetic stainless steel (SUS303, 304, etc.), resin, ceramics and the like are preferable in addition to the above aluminum.

  In the second embodiment, the foaming mold can be conveyed by the conveyor. However, a foaming mold may be disposed between a pair of pole pieces without using a conveyor. Here, the shape of the pole piece is not necessarily limited to the rectangular thin plate shape. What is necessary is just to determine the shape of a pole piece suitably so that a desired magnetic field may be formed. Further, the pole piece is not necessarily arranged. From the viewpoint of reducing the magnetic resistance, the gap between the yoke part or pole piece and the foaming mold should be as small as possible.

  Next, the present invention will be described more specifically with reference to examples.

(1) Production of urethane foam molded article A urethane foam molded article containing a magnetic filler as a magnetic substance was produced using the magnetic induction foam molded apparatus of the first embodiment. First, a foamed urethane resin raw material was prepared as follows. Polyether component polyether polyol (“S-0248” manufactured by Sumika Bayer Urethane Co., Ltd., average molecular weight 6000, number of functional groups 3, OH value 28 mg KOH / g) 100 parts by weight, crosslinking agent diethylene glycol (manufactured by Mitsubishi Chemical Corporation) 2 weights Parts, 2 parts by weight of foaming agent water, 1 part by weight of a tetraethylenediamine catalyst (“No. 31” manufactured by Kao) and a silicone foam stabilizer (“SZ-1313” manufactured by Nihon Unica) 0.5 A premix polyol was prepared by blending with parts by weight. Diphenylmethane diisocyanate (MDI) as a polyisocyanate component (“NE1320B” manufactured by BASFINOAC polyurethane, NCO = 44.8 wt%) was added to the prepared premix polyol and mixed to obtain a foamed urethane resin material. Here, the blending ratio of the polyol component and the polyisocyanate component (PO: ISO) was set to PO: ISO = 78.5: 21.5, with the total weight of both being 100%.

  Next, the foamed urethane resin raw material was mixed with a magnetic filler to obtain a foamed raw material. As the magnetic filler, a stainless fiber (“KC Metal Fiber SUS430F” manufactured by Niji Co., Ltd .: diameter of about 30 μm, length of about 2 mm) was used. The aspect ratio of this stainless steel fiber was determined to be 4444. The magnetic filler was blended in 121 parts by weight with respect to 100 parts by weight of the polyether polyol of the polyol component.

  Thereafter, the foaming raw material was poured into a foam-type annular cavity (see FIGS. 4 and 5 described above; radial length 30 mm × axial length 20 mm) and sealed. Subsequently, a foaming mold was installed between the pair of electromagnet parts, and foam molding was performed in a magnetic field (see FIGS. 2 and 3 above). Foam molding was performed with a magnetic field for the first 2 minutes and 37 seconds, and for about 5 minutes without applying a magnetic field. The magnetic field was formed by switching the direction of current as appropriate for 37 seconds until the voltage value reached the maximum, and by switching the direction of current every second for about 2 minutes.

  After the foam molding was completed, the mold was removed to obtain a donut-shaped urethane foam molded article having a cylindrical hole at the center. This urethane foam molded article was used as the foam molded article of Example 1. The compounding quantity of the magnetic filler in the foaming molding of Example 1 was 1 volume% when the volume of the urethane foaming molding was 100 volume%.

  Further, using the same magnetic induction foam molding apparatus as described above, a urethane foam molded article was manufactured without switching the current, that is, with the direction of the magnetic lines of force kept constant from the core rod magnet portion to the ring magnet portion. The same foam material as that of Example 1 was used as the foam material. The obtained urethane foam molded article was used as the foam molded article of Example 2.

  The photograph of the foaming molding of Example 1 is shown in FIGS. FIG. 9 is a top view photograph of the foam molded article of Example 1. FIG. 10 is a photograph of the bottom surface of the foamed molded product. FIG. 11 is a cross-sectional photograph in the hole axial direction of the foamed molded product. Moreover, the photograph of the foaming molding of Example 2 is shown in FIGS. 12 is a top view photograph of the foamed molded product of Example 2. FIG. FIG. 13 is a photograph of the bottom surface of the foamed molded product. FIG. 14 is a cross-sectional photograph in the hole axial direction of the foamed molded product. In addition, about any foaming molding, in order to observe the cross section of a hole axial direction, it cut | disconnected in the same direction. For this reason, the upper surface photograph and the lower surface photograph shown in FIG. 9, FIG. 10, FIG. 12, and FIG. 13 are taken from the cut half of each foamed molded product.

  As shown in FIGS. 9-11, in the foaming molding of Example 1, the magnetic filler was orientated radially from the hole. Further, as shown in FIGS. 9 and 11, the magnetic substance was slightly concentrated around the peripheral edge and the hole near the upper surface. This is presumably because the magnetic flux density was large in the vicinity of the upper ends of the core rod magnet portion and the ring magnet portion that partition the annular cavity. Similarly, in the foamed molded product of Example 2, as shown in FIGS. 12 to 14, the magnetic filler was radially oriented from the hole. In the foamed molded product of Example 2, as shown in FIGS. 12 and 14, many magnetic materials were oriented around the hole near the upper surface. Further, as shown in FIG. 13, many magnetic materials were also oriented at the peripheral portion of the lower surface. Foam molding of the foam molded body of Example 2 was performed with the direction of the lines of magnetic force constant. For this reason, compared with the foaming molding of Example 1, it is thought that a magnetic body was hard to disperse | distribute and it was thought that more magnetic bodies concentrated on the place with a large magnetic flux density.

(2) Anisotropy test About the foaming molding of Example 1, the displacement amount with respect to the load from a different direction was measured, and the anisotropy was evaluated. For comparison, the following two types of urethane foam molded articles were produced, and the anisotropy was similarly evaluated for these. Firstly, only the foamed urethane resin raw material was foam-molded without blending a magnetic material. The obtained urethane foam molded article was used as the foam molded article of Comparative Example 1. Second, the same foaming raw material as described above was foam-molded without applying a magnetic field. The obtained urethane foam molded article was used as the foam molded article of Comparative Example 2. The shapes and sizes of the foam molded articles of Comparative Examples 1 and 2 are the same as those of the foam molded article of Example 1.

(2-1) A 20 mm square cube with the axial direction of the hole as one side in the vertical direction was cut out from the foamed molded products of Example 1 and Comparative Examples 1 and 2 to prepare a sample. First, in order to create a load-displacement curve in the axial direction of the hole for the foamed molded product of Example 1, a load was applied substantially perpendicular to the upper surface (20 mm × 20 mm = 4 cm ² ) of the sample (the compression direction was The axial displacement of the hole) and the displacement with respect to the load were measured. Next, in order to create a load-displacement curve in the orientation direction of the magnetic material, a load is applied substantially perpendicular to the right surface (20 mm × 20 mm = 4 cm ² ) of the sample (the compression direction is substantially the same as the orientation direction of the magnetic material). ), The amount of displacement relative to the load was measured. Similarly, with respect to the foamed molded products of Comparative Examples 1 and 2, a load was applied to each of the upper surface and the right surface of the sample, and a displacement amount with respect to the load was measured. 15 to 17 show load-displacement curves in each measurement.

  As shown in FIG. 15, in the sample of Example 1, the rigidity in the orientation direction of the magnetic material (left and right direction of the sample) was higher than in the axial direction of the hole (up and down direction of the sample). Moreover, when the amount of displacement was 2 mm (compression ratio 10%) when the compression was performed from the right surface and when the compression was performed from the upper surface, the former was 6.62 times the latter. On the other hand, as shown in FIGS. 16 and 17, the samples of Comparative Examples 1 and 2 showed almost no difference in rigidity due to the difference in the compression direction. About each sample, the static spring constant at the time of compressing from the upper surface and the static spring constant at the time of compressing from the right surface were compared like Example 1. As a result, it was 0.61 times for the sample of Comparative Example 1 and 1.02 times for the sample of Comparative Example 2. From the above, in the urethane foam molded article of the present invention, it was confirmed that the characteristics in the orientation direction of the magnetic material and the characteristics in the axial direction of the hole portion are significantly different.

  (2-2) In the evaluation of the anisotropy, a sample cut out to a predetermined size from each urethane foam molded article was used. Here, the result of having measured the displacement amount with respect to the load from a different direction using the foaming molding of Example 1 and Comparative Examples 1 and 2 as it is is shown. First, in order to create a load-displacement curve in the axial direction of the hole, a load was applied substantially perpendicular to the upper surface of each foamed molded product (the compression direction was the axial direction of the hole), and the displacement relative to the load was measured. . Next, a ring member was wrapped around and fixed to the outer peripheral portion of each foamed molded product, and a cylindrical jig was inserted into the hole. The jig was pressed against the ring member side of the outer peripheral portion, a load was applied in the radial direction from the hole portion (the compression direction was substantially the same as the orientation direction of the magnetic material), and the displacement with respect to the load was measured. 18 to 20 show load-displacement curves in each measurement.

  As shown in FIGS. 19 and 20, in the foamed molded products of Comparative Examples 1 and 2, there was no significant difference in the load-displacement curve between the axial direction (thickness direction) of the hole and the radial direction. . On the other hand, in the foam molded article of Example 1, as shown in FIG. 18, the load-displacement curve is different in the axial direction (thickness direction) of the hole and the orientation direction (radial direction) of the magnetic substance. It was very different. Therefore, also from this result, it turns out that the foaming molding of Example 1 has anisotropy.

  The urethane foam molded article of the present invention can be used in a wide range of fields such as automobiles, electronic equipment, and architecture. Particularly, it is suitable for applications requiring anisotropy, for example, a rubber member for an upper support for a suspension of a vehicle, a bound stopper for absorbing an impact, and the like. Applications that require heat dissipation, such as engine covers and side covers placed in the engine room of a vehicle to reduce engine noise, sound absorbing materials for motors of office automation (OA) equipment and home appliances, personal computers, etc. It is suitable as a heat-absorbing sound absorbing material for electronic devices, a sound absorbing material for inner and outer walls of houses, and the like.

It is explanatory drawing about the maximum length in each shape of a magnetic filler, the length of an axial direction cross-section horizontal side, and the length of an axial direction cross-section vertical side. It is a perspective view of the magnetic induction foam molding apparatus of 1st embodiment of this invention. It is a fragmentary sectional view of the magnetic induction foam molding apparatus. It is a disassembled perspective sectional view of a foaming type. It is a perspective sectional view of a foaming type. It is VI-VI sectional drawing in FIG. It is a perspective view of the magnetic induction foam molding apparatus of 2nd embodiment of this invention. It is VIII-VIII sectional drawing of FIG. 2 is a top view photograph of the foamed molded product of Example 1. FIG. It is a lower surface photograph of the foaming molding. It is a hole axial direction cross-sectional photograph of the foaming molding. 3 is a top view photograph of a foamed molded product of Example 2. FIG. It is a lower surface photograph of the foaming molding. It is a hole axial direction cross-sectional photograph of the foaming molding. It is the load-displacement curve in the sample cut out from the foaming molding of Example 1. It is the load-displacement curve in the sample cut out from the foaming molding of the comparative example 1. It is the load-displacement curve in the sample cut out from the foaming molding of the comparative example 2. 2 is a load-displacement curve in the foamed molded product of Example 1. FIG. 4 is a load-displacement curve in the foamed molded article of Comparative Example 1. 4 is a load-displacement curve in a foamed molded article of Comparative Example 2.

Explanation of symbols

1: Magnetic induction foam molding apparatus 2D, 2U: Electromagnet part 2a-2d: Electromagnet part 20D, 20U: Core part 21D, 21U: Coil part 210D, 210U: Conductor 3: Yoke part 3D, 3U: Yoke part 30D, 30U: Pole piece 4: Foaming type 40D: Lower die 40U: Upper die 41: Core bar magnet part 42D, 42U: Ring magnet part 43: Annular cavity 44: Guided part 5: AC power supply device (magnetic field switching means)
60: Guide part L: Magnetic field line

Claims (10)

A hole,
A radially oriented magnetic body approximately centered on the hole;
A urethane foam molded article comprising:   2. The urethane foam molded article according to claim 1, wherein a static spring constant in an orientation direction of the magnetic body is at least twice a static spring constant in an axial direction of the hole.   The urethane foam molded article according to claim 1 or 2, wherein the magnetic body is a magnetic filler having an aspect ratio of 2 or more. A foam raw material preparation step of preparing a foam raw material including a foamed urethane resin raw material and a magnetic material;
A foam molding step of injecting the foaming raw material into a foam-type annular cavity, generating a magnetic field by generating a magnetic field line radially about the axial portion of the annular cavity, and foam-molding in the magnetic field;
A method for producing a urethane foam molded article comprising:   The method for producing a urethane foam molded article according to claim 4, wherein in the foam molding step, foam molding is performed while reversing the direction of the magnetic lines of force before the foam raw material is solidified. A foam mold in which an annular cavity is defined;
A core bar magnet portion disposed on the shaft portion of the annular cavity;
A ring magnet portion disposed on the peripheral edge of the annular cavity,
A magnetic induction foam molding apparatus, wherein a magnetic field line is generated between the core bar magnet portion and the ring magnet portion to perform foam molding. An electromagnet part having a core part made of a ferromagnetic material and a coil part arranged on the outer peripheral surface of the core part;
The magnetic induction foam molding apparatus according to claim 6, wherein the core bar magnet part and the ring magnet part are magnetized so as to have different magnetic poles by the electromagnet part.   The magnetic induction foam molding apparatus according to claim 7, further comprising a yoke portion connected to the core portion of the electromagnet portion and forming a closed loop magnetic path passing through the annular cavity.   Furthermore, the magnetic field switching means which reverses the direction of the line of magnetic force generated between the said core rod magnet part and the said ring magnet part by switching the direction of the electric current sent through the said coil part of the said electromagnet part is provided. Item 9. The magnetic induction foam molding apparatus according to Item 8. The core rod magnet part and the ring magnet part are incorporated in the foaming mold,
The inner peripheral surface of the annular cavity of the foaming mold is formed by the core rod magnet portion, and the outer peripheral surface of the annular cavity is formed by the ring magnet portion, respectively. Magnetic induction foam molding equipment.