JP2011148954A - Polymer composite material molding and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer composite material molding improved in various characteristics such as mechanical, thermal, optical and electrical characteristics in orthogonal two directions and a method for producing the same. <P>SOLUTION: In the polymer composite material molding, first fibers Fp whose anisotropic magnetic susceptibility is a positive value and second fibers Pn whose anisotropic magnetic susceptibility is a negative value are contained in a polymer material M. The first fibers Fp are oriented in a first direction which is the thickness direction of the polymer composite material molding. The second fibers Fn are oriented in a second direction perpendicular to the first direction, that is, a surface direction of the polymer composite material molding. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polymer composite material molded body in which fibers are blended in a polymer material and a method for producing the same.

  Conventionally, a polymer composite material molded body in which fibers such as glass fiber, carbon fiber, metal fiber, aramid fiber, polybenzazole fiber and the like are blended with a polymer material is widely known. Also widely known are woven fabrics made of long fibers such as carbon fibers and glass fibers, prepregs in which a polymer material is impregnated with fibers aligned in one direction, or plate-like molded bodies obtained by laminating and curing prepregs. Yes. In such a plate-shaped molded body, mechanical properties such as elastic modulus and strength in the surface direction, and thermal characteristics such as a thermal expansion coefficient and thermal conductivity are enhanced by fibers extending along the surface of the molded body.

  Recently, various mechanical parts used in electronic circuits and the like have been required to improve various characteristics in the thickness direction in addition to mechanical characteristics, thermal characteristics, optical characteristics, and electrical characteristics in the surface direction. For this reason, as a manufacturing method of a polymer composite material molded body in which fibers are oriented in both the surface direction and the thickness direction, those described in Patent Document 1 and Patent Document 2 have been proposed.

  According to the method described in Patent Document 1, first, a three-dimensional fabric is impregnated with a resin, and the surface of the resin-impregnated product is brought into a semi-cured state. Next, the impregnated material is disposed between a pair of upper and lower plates, and each plate is brought into close contact with the surface of the impregnated material. And after extending the space | interval between both plates, both plates are shifted to a horizontal direction and an intermediate fiber layer is aligned vertically. Then, a fiber reinforced plastic panel is manufactured by hardening resin. Moreover, according to the method described in Patent Document 2, first, a three-dimensional fabric is produced using carbon fibers. Then, the three-dimensional fabric is impregnated with a phenol resin and molded into a predetermined shape. After molding, a highly impregnated three-dimensional fabric is produced by firing a phenol resin impregnated product in a nitrogen atmosphere.

  However, according to the methods described in Patent Documents 1 and 2, in the step of impregnating a liquid polymer material into a three-dimensional fabric prepared in advance, a void (void) is formed between the fibers constituting the fabric and the polymer material. ) Is likely to occur. As a method for solving such a problem, for example, a method described in Patent Document 3 has been proposed. According to the method described in Patent Document 3, a fiber cloth such as carbon fiber is first placed in a mold. Next, a polymer composition in which short fibers such as carbon fibers are mixed in a polymer material is poured into a mold and impregnated into a fiber cloth in the mold. And a short fiber is orientated in the direction perpendicular | vertical to the surface of a fiber cloth by applying a magnetic field from the outside. After the orientation of the magnetic field, the liquid polymer material is cured to produce a molded body of the polymer composite material.

Japanese Patent Laid-Open No. 6-339997 JP-A-9-207236 JP 2004-276478 A

  However, even with the method described in Patent Document 3, bubbles may be entrained in the polymer composition in the step of pouring the liquid polymer composition into the mold and impregnating the fiber cloth. In this way, it is very difficult to remove the bubbles entrained in the polymer composition, and as a result, a molded body containing bubbles is formed inside, which may cause an increase in the defective product rate. Further, in the process of pouring the liquid polymer composition into the mold, the lamination interval of the fiber cloth is likely to be uneven, and the arrangement of the fibers may be biased. For this reason, the polymer composite material molded body may not be produced as desired, and the intended isotropic thermal expansion coefficient may not be obtained. Furthermore, since the process of arranging the fiber cloth in the mold in advance and the process of preparing a liquid polymer material blended with short fibers and pouring them into the mold are performed separately, the product productivity is low. There is also a problem.

  An object of the present invention is to provide a polymer composite material molded body in which various properties such as mechanical properties, thermal properties, optical properties, and electrical properties are improved in two orthogonal directions, and a method for producing the same.

  In order to achieve the above object, the invention according to claim 1 is a polymer composite material including at least two types of fibers in a polymer material. A first fiber having a positive value of a modulus and a second fiber having a negative value of an anisotropic magnetic susceptibility, the first fiber being oriented in a first direction, The gist is that the fibers are oriented in a second direction orthogonal to the first direction.

  According to this structure, the characteristic in the 1st direction of a polymeric composite material molded object improves by utilizing the characteristic of a 1st fiber. Moreover, the characteristic in the 2nd direction of a polymeric composite material molded object improves by utilizing the characteristic of a 2nd fiber. Thereby, in the polymer composite material molded body, characteristics in two orthogonal directions can be improved. Note that the second direction includes an arbitrary direction along a plane orthogonal to the first direction. The characteristics include various characteristics such as mechanical characteristics, thermal characteristics, optical characteristics, and electrical characteristics.

The gist of the invention described in claim 2 is that, in the invention described in claim 1, the fiber lengths of the first and second fibers are 2 mm or less.
With this configuration, collision between the first fiber having a positive anisotropic magnetic susceptibility that is easily oriented and the second fiber having a negative anisotropic magnetic susceptibility is avoided. And the second fibers can be smoothly oriented in the first and second directions, respectively.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the first fiber is made of carbon fiber, aramid fiber, polybenzazole fiber, polyimide fiber, polyphenylene sulfide fiber, halogenated polyolefin fiber. The gist is to be selected more.

  According to this configuration, for example, by selecting a carbon fiber as the first fiber, it is possible to effectively increase the thermal conductivity, the electrical resistance value, and the like in the first direction of the polymer composite material molded body.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the second fiber is selected from the group consisting of polyethylene fiber, polylactic acid fiber, and polyoxymethylene fiber. This is the gist.

  According to this configuration, for example, by selecting a polyethylene fiber as the second fiber, the strength, elastic modulus, and the like in the second direction of the polymer composite material molded body can be effectively increased.

  The invention according to claim 5 is a method for producing a molded article of a polymer composite material, wherein the first fiber having a positive anisotropic magnetic susceptibility in the polymeric material, and the anisotropic magnetic susceptibility And a step of preparing a liquid polymer composition by blending the second fiber having a negative value, and after injecting the polymer composition into the mold, a magnetic field is applied to the polymer composition in the mold. By applying, the step of orienting the first fiber in the first direction and orienting the second fiber in the second direction orthogonal to the first direction, and solidifying the polymer composition after magnetic field orientation And a step of forming a molded body.

  According to this configuration, first, a polymer composition is prepared in which at least two types of fibers that are oriented in the first direction and the second direction, respectively, are blended. And after inject | pouring a liquid polymer composition into a metal mold | die, a magnetic field is applied to the polymer composition in a metal mold | die. For this reason, unlike conventional methods in which a fiber cloth is placed in a mold, a polymer composition containing fibers is injected into the mold, and then a magnetic field is applied to the polymer composition in the mold, the polymer composition Involvement of bubbles in the object and unevenness of the fiber cloth are eliminated, and the number of processes can be reduced. Therefore, it is possible to provide a polymer composite material molded body that can be produced efficiently while suppressing variations in quality characteristics.

The gist of the invention described in claim 6 is that, in the invention described in claim 5, the fiber lengths of the first and second fibers are 2 mm or less.
With this configuration, collision between the first fiber having a positive anisotropic magnetic susceptibility and the second fiber having a negative anisotropic magnetic susceptibility that are easily aligned is avoided in the alignment step. Therefore, the first and second fibers can be smoothly oriented in the first and second directions, respectively. Therefore, variation in quality characteristics can be further suppressed.

  According to the present invention, a molded product of a polymer composite material in which various characteristics such as mechanical characteristics, thermal characteristics, optical characteristics, and electrical characteristics are improved in two directions orthogonal to each other, and production with reduced variation in quality characteristics are efficiently produced. It is possible to provide a molded article of a polymer composite material that can be used.

The model perspective view which shows the orientation state of the fiber of a polymer composite material molded object. The schematic cross section which shows the orientation state of the fiber of a polymer composite material molded object.

Hereinafter, an embodiment embodying a polymer composite material molded body and a method for producing the same according to the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIGS. 1 and 2, the polymer composite material molded body of the present invention contains at least two types of fibers Fp and Fn having different signs of anisotropic magnetic susceptibility in the polymer material M. . The first fibers Fp having a positive anisotropic magnetic susceptibility are oriented in the first direction in the polymer material M, that is, in the thickness direction of the polymer composite molded body shown in FIG. The second fibers Fn having a negative anisotropic magnetic susceptibility are oriented in a second direction orthogonal to the first direction, that is, in the plane direction of the polymer composite material compact shown in FIG. ing.

  According to the present invention, it is possible to provide a polymer composite material molded body in which various properties such as mechanical properties, thermal properties, optical properties, and electrical properties are improved in two orthogonal directions. In addition, it is possible to provide a method for producing a molded article of a polymer composite material that can be produced efficiently while suppressing variations in quality characteristics.

  The polymer material M is preferably selected according to the properties required for the polymer composite molded body. Examples of properties required for the polymer composite molded body include mechanical properties, thermal properties, optical properties, electrical properties, durability, and reliability. The polymer material M is preferably selected in consideration of the manufacturing efficiency and economy in addition to the above required characteristics. Specific examples of the polymer material M include, for example, thermoplastic resins, thermoplastic elastomers, curable resins, crosslinkable rubbers, and the like. Among these, from the viewpoint that both fibers Fp and Fn can be easily oriented, it is preferable to use a high-viscosity material that is a low-viscosity liquid when the fibers Fp and Fn are mixed or can be lowered when heated and melted. . For these reasons, as the polymer material M, for example, at least one selected from the group consisting of epoxy resins, unsaturated polyester resins, phenol resins, acrylic resins, urethane resins, polyimide resins, silicone resins, and liquid rubbers It is preferable to use a polymer material. More specifically, the polymer material M is preferably a polymer precursor such as a liquid epoxy resin, an unsaturated polyester resin, or liquid rubber, or a molten polymer material having a low state viscosity. In addition, as these polymer materials M, one type of resin material may be used alone, or two or more types of resin materials may be used in combination. Furthermore, a polymer alloy produced by selecting a plurality of polymer materials M and mixing them may be used. Specific examples of the curing method of the curable resin or the crosslinking method of the crosslinkable rubber include a thermal curing method, a photocuring method, a moisture curing method, a radiation or electron beam irradiation method, and the like.

  The polymer material M contains first and second fibers Fp and Fn having different positive and negative signs in a uniformly dispersed state. Examples of the first fiber Fp having a positive anisotropic magnetic susceptibility include carbon fiber, aramid fiber, polybenzazole fiber, polyimide fiber, polyphenylene sulfide fiber, and halogenated polyolefin fiber. Among these fibers, carbon fibers are preferable from the viewpoint that the thermal conductivity, electrical resistance value, and the like in the fiber orientation direction can be effectively increased. On the other hand, as the second fiber Fn having a negative anisotropic magnetic susceptibility, a polyethylene fiber, a polylactic acid fiber, a polyoxymethylene fiber, or the like is used from the viewpoint of obtaining a molded product having a high strength and a high elastic modulus. preferable.

The first and second fibers Fp and Fn are each oriented in a specific direction in the polymer material M by a magnetic field applied from the outside. The ease of orientation of the fibers by the magnetic field depends on the magnitude of the anisotropic magnetic susceptibility of the first and second fibers Fp and Fn, in addition to the strength of the applied magnetic field. If the absolute value of the anisotropic magnetic susceptibility χ _a is smaller than 1 × 10 ^−9, it becomes difficult to orient each of the first and second fibers Fp and Fn in a specific direction by a magnetic field. That is, as the absolute value of the anisotropic magnetic susceptibility χ _a of the first and second fibers Fp and Fn is larger, both the fibers Fp and Fn can be more highly orientated by a magnetic field. For this reason, the absolute value of the anisotropic magnetic susceptibility χ _a of the first and second fibers Fp, Fn is preferably 1 × 10 ⁻⁹ or more, more preferably 5 × 10 ⁻⁹ or more, and 1 ×. 10 ⁻⁸ or more is more preferable.

Here, the anisotropic magnetic susceptibility χ _a is a magnetic susceptibility obtained by subtracting the magnetic susceptibility χ _{垂直 in the} direction perpendicular to the fiber axis from the magnetic susceptibility χ _{// in the} fiber axis direction generated by applying a magnetic field from the outside. It is a value (CGS unit system) showing the anisotropy of. A fiber having a positive anisotropy magnetic susceptibility χ _a , such as a carbon fiber, an aramid fiber, or a polybenzazole fiber, is oriented parallel to the magnetic field lines in a magnetic field atmosphere. A fiber whose anisotropic magnetic susceptibility χ _a has a negative value, for example, a polyethylene fiber, a polyoxymethylene fiber, and the like, has a magnetic field acting in a direction perpendicular to the magnetic field lines. It is oriented in any direction along a plane perpendicular to the magnetic field lines. The anisotropic magnetic susceptibility χ _a can be measured by a known method such as a magnetic anisotropic torque meter, a vibration magnetometer, a SQUID (superconducting quantum interference device), or a suspension method.

  The lengths and diameters of the first and second fibers Fp and Fn are preferably selected in consideration of manufacturing efficiency, reliability, and the like. In order to further increase the degree of orientation of the first and second fibers Fp and Fn in order to improve the functionality of the polymer composite molded body, the fiber aspect indicating (fiber length) / (fiber diameter) It is preferable to increase the ratio. However, as the fiber length becomes longer than 10 mm, the first and second fibers Fp and Fn are not easily dispersed uniformly in the polymer material M, which is not preferable. Moreover, since the viscosity of a polymer composition rises and moldability deteriorates, it is not preferable. Furthermore, as the fiber length becomes longer, the fibers tend to be entangled with each other, and it becomes difficult to orient the fibers in a certain direction, which is not preferable. In consideration of the fluidity of the polymer material M and the ease of orientation of the fibers Fp and Fn, it is preferable to use short fibers having a short fiber length as the first and second fibers Fp and Fn. Specifically, the fiber length of the first and second fibers Fp and Fn is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 2 mm or less.

  The lower limit of the fiber length of the fiber is preferably selected in consideration of the production efficiency and reliability. When the fiber length is less than 10 μm, even if the diameters of the first and second fibers Fp and Fn are 0.1 μm, the aspect ratio is less than 100. Or thermal characteristics may not be obtained. For this reason, although it changes with the diameters of the first and second fibers Fp, Fn, the fiber length of each fiber Fp, Fn is preferably at least 10 μm or more, more preferably 50 μm or more. Further, the diameter of the first and second fibers Fp and Fn is preferably 0.1 to 30 μm in consideration of the ease of orientation of the fibers Fp and Fn. The cross-sectional shape of the first and second fibers Fp and Fn may be any shape other than a circle, an ellipse, a polygon, and the like.

  In the polymer composite material molded body, the first fibers Fp and the second fibers Fn are arranged so as to be orthogonal to each other in a uniformly dispersed state. For this reason, in the polymer composite material molded body, mechanical properties such as elastic modulus and strength, thermal expansion coefficient and thermal conductivity are measured in both the thickness direction which is the first direction and the surface direction which is the second direction. The thermal characteristics such as the above, the electrical characteristics such as the electrical resistance value, etc. are enhanced to a desired value. For example, the concentrations of the first and second fibers Fp and Fn may be adjusted so that the linear expansion coefficients are uniform in all directions of the polymer composite material molded body. In this case, the ratio of the first fiber Fp to the second fiber Fn varies depending on the thermal characteristics and specific gravity of the first and second fibers Fp and Fn, but is preferably 10/1 to 1/10. 8/1 to 1/8 is more preferable, and 6/1 to 1/6 is still more preferable. In addition, the types and concentrations of the first and second fibers Fp and Fn may be adjusted in accordance with the application of the polymer composite material molded body so that the characteristics in each direction are different. For example, when a polymer composite material molded body is applied to an electronic circuit board, the first and second layers are designed so that the thermal conductivity in the thickness direction of the molded body is increased and the thermal expansion coefficient in the surface direction of the molded body is decreased. The types and concentrations of the fibers Fp and Fn can be selected.

  As a shape of the polymer composite material molded body, an arbitrary shape can be selected according to the application, and examples thereof include a cube, a sphere, a cylinder, a plate, a film, a rod, a tube, and the like. Moreover, as the polymer composite material molded body, the first fibers Fp and the second fibers Fn may be uniformly dispersed throughout the molded body, or locally in one or a plurality of portions. It may be scattered. For example, in the latter case, when the polymer composite material molded body is applied to an electronic circuit board, the first fiber Fp and the second fiber Fn are locally applied to a portion where an IC chip having a large amount of heat generation is mounted. It is possible to partially increase the thermal conductivity in the thickness direction while keeping the thermomechanical characteristics of the portion isotropic.

  Examples of uses of the polymer composite material molded body include mechanical parts, mechanical parts, automobile parts, electrical products, and the like. More specifically, various mechanical parts used in electronic circuits and the like, housings for electrical products and automotive products. , Substrates, conductive belts and the like.

Next, the manufacturing method of said polymeric composite material molded object is demonstrated.
The polymer composite material molded body includes a preparation step of preparing a liquid polymer composition by blending the first fiber Fp and the second fiber Fn in the polymer material M, and a polymer composition. After injecting into the mold, by applying a magnetic field to the polymer composition in the mold, the first fibers Fp are oriented in the first direction, and the second fibers Fn are orthogonal to the first direction. Manufactured through an alignment step of aligning in the second direction and a molding step of solidifying the polymer composition to form a molded body after magnetic field alignment.

  In the preparation step, the polymer material M and the first and second fibers Fp and Fn are blended in order to obtain a polymer composition as a material for the polymer composite material molded body. Then, a polymer composition is prepared by mixing until both fibers Fp and Fn are uniformly dispersed in the polymer material M. As a mixing apparatus, for example, a known mixing and kneading apparatus such as a blender, a mixer, a roll, and an extruder is used. Further, at the time of mixing, in order to remove bubbles mixed in the polymer material M, it is preferable to mix while reducing pressure or increasing pressure.

  The blending amounts of the first and second fibers Fp and Fn are appropriately determined depending on the required performance of the final product. However, if the blending amount of the first and second fibers Fp, Fn is too large, the viscosity of the polymer composition increases and the fluidity is impaired, so that it is difficult to control the orientation of both fibers Fp, Fn. The blending amount of the first and second fibers Fp and Fn needs to be appropriately set according to the specific gravity and length of the first and second fibers Fp and Fn. For example, when carbon fibers having an average length of 50 μm are used as the first fibers Fp and polyethylene fibers having a length of 0.5 to 1 mm are used as the second fibers Fn, the carbon fibers 50 are used with respect to 100 parts by weight of the polymer material. It is preferable that it is 10 parts by weight or less of polyethylene fiber.

  Moreover, you may use small amounts of additives, such as another filler, a plasticizer, a crosslinking agent, a coloring agent, a stabilizer, a solvent, as needed for a polymer composition. In addition, in order to improve the wettability and adhesiveness of the first and second fibers Fp and Fn with respect to the polymer material M, the surfaces of both the fibers Fp and Fn are preliminarily degreased and washed, or ultraviolet irradiation treatment, Activation treatment such as corona discharge treatment, plasma treatment, flame treatment or ion implantation, or surface treatment with a coupling agent such as silane, titanium or aluminum, resorcin formalin latex or the like is preferable. As a result, the first and second fibers Fp, Fn can be easily dispersed and mixed in the polymer material M, and the blending amount of the first and second fibers Fp, Fn can be increased. In addition, the first and second fibers Fp and Fn can be easily oriented by the magnetic field, and the production efficiency is improved.

  Further, in order to prevent sedimentation of the first and second fibers Fp and Fn in the polymer composition and to promote the orientation of both fibers Fp and Fn, the fiber Fp is reduced by reducing the viscosity of the polymer composition. , Fn is increased, or the specific gravity difference between the two fibers Fp, Fn and the polymer material M is preferably reduced. From such a viewpoint, it is preferable to add a volatile organic solvent or a reactive plasticizer to the polymer composition. Examples of the organic solvent added to the polymer composition include toluene, methyl ethyl ketone, and acetone. Examples of the reactive plasticizer include vinyl monomers such as styrene, acrylic monomers such as methyl methacrylate and triethylene glycol diacrylate, and epoxy monomers such as phenyl glycidyl ether and diethylene glycol diglycidyl ether.

  Next, an alignment process is performed. Prior to the alignment step, first, a mold for forming a polymer composite material compact is prepared, and a liquid polymer composition is poured into the mold. At this time, if the polymer composition is liquid at room temperature, it is necessary to relax the orientation of both fibers Fp and Fn in the flow direction by injection of the polymer composition into the mold. For this reason, it is preferable to apply vibration to the mold after injecting the polymer composition into the mold. Subsequently, in order to orient the first and second fibers Fp and Fn in the polymer composition, a magnetic field is applied to the polymer composition from the outside. Specifically, a N pole and an S pole of a permanent magnet or an electromagnet are respectively disposed on a pair of opposing surfaces of the mold, and a magnetic field is applied to the polymer composition in the mold. Thereby, since both fibers Fp and Fn in the polymer composition are magnetized, the first and second fibers Fp and Fn are respectively oriented in the direction of magnetically stabilizing the fiber axis with respect to the lines of magnetic force. The Specifically, the first fiber Fp having a positive anisotropic magnetic susceptibility is oriented in a first direction parallel to the magnetic field lines, and the first fiber Fp having a negative anisotropic magnetic susceptibility has a negative value. The two fibers Fn are oriented in a second direction perpendicular to the magnetic field lines.

  The magnetic field generating means is preferably selected in consideration of manufacturing efficiency, economic efficiency, and the like. For example, permanent magnets, electromagnets, coils, superconducting magnets, and the like are preferable. The magnetic field is preferably formed so that practical and effective orientation of both fibers Fp and Fn can be achieved. That is, the magnetic flux density representing the strength of the magnetic field is preferably 0.1 to 30 Tesla. Moreover, in order to orient in a fixed direction using the very weak magnetic anisotropy which both fibers Fp and Fn have, it is preferable to raise a magnetic flux density and to form a stronger magnetic field. Specifically, the magnetic flux density is preferably 0.5 Tesla or higher, and more preferably 2 Tesla or higher. In addition, when improvement of various characteristics such as mechanical characteristics is limited to a part of the polymer composite material molded body, only a part of the polymer composition may be arranged in a magnetic field atmosphere. In order to promote the orientation of the first and second fibers Fp and Fn in the polymer composition, a magnetic field may be applied while applying vibration.

  Next, a molding process is performed. In the molding step, the liquid polymer composition is solidified in a state where the first and second fibers Fp and Fn are oriented in the first and second directions, respectively. The polymer composition is solidified by a crosslinking reaction, cooling solidification, or the like according to the type of the polymer material M. For example, when a thermoplastic resin is used, the liquid resin is cooled below the melting point in order to solidify the polymer composition. Moreover, when a thermosetting resin is used, in order to solidify the polymer composition, the liquid resin is subjected to reaction curing or a crosslinking reaction. In addition, as a shaping | molding method of a polymeric composite material molded object, an extrusion molding method, an injection molding method, a compression molding method, a transfer molding method, a blow molding method, a vacuum molding method, a rotation molding method etc. are mentioned, for example. Through such a series of steps, a polymer composite material molded body is produced.

The effect exhibited by the above embodiment is described collectively below.
(1) The polymer material M contains at least two types of fibers Fp and Fn having different signs of anisotropic magnetic susceptibility. The first fibers Fp having a positive anisotropic magnetic susceptibility are oriented in the first direction in the polymer material M. Further, the second fibers Fn having a negative anisotropic magnetic susceptibility are oriented in a second direction orthogonal to the first direction. According to this structure, the characteristic in the 1st direction of a polymeric composite material molded object improves by utilizing the characteristic of the 1st fiber Fp. Moreover, the characteristic in the 2nd direction of a polymeric composite material molded object improves by utilizing the characteristic of the 2nd fiber Fn. Thereby, in the polymer composite material molded body, characteristics in two orthogonal directions can be improved.

  (2) The fiber length of the first and second fibers Fp, Fn is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 2 mm or less. By this configuration, collision between the first fiber Fp whose anisotropic magnetic susceptibility that is easily oriented is a positive value and the second fiber Fb whose anisotropic magnetic susceptibility is a negative value is avoided. The first and second fibers Fp and Fn can be smoothly oriented in the first and second directions, respectively.

  (3) Examples of the first fiber Fp include carbon fiber, aramid fiber, polybenzazole fiber, polyimide fiber, polyphenylene sulfide fiber, and halogenated polyolefin fiber. According to this configuration, for example, by selecting a carbon fiber as the first fiber Fp, it is possible to effectively increase the thermal conductivity, conductivity, and the like in the first direction of the polymer composite material molded body.

  (4) Examples of the second fiber Fn include polyethylene fiber, polylactic acid fiber, and polyoxymethylene fiber. According to this configuration, for example, by selecting a polyethylene fiber as the second fiber Fn, the strength, elastic modulus, and the like in the second direction of the polymer composite material molded body can be effectively increased.

  (5) The polymer composite material molded body includes a preparation step of preparing a liquid polymer composition by blending the first fiber Fp and the second fiber Fn in the polymer material M, and a polymer. After injecting the composition into the mold, by applying a magnetic field to the polymer composition in the mold, the first fibers Fp are oriented in the first direction, and the second fibers Fn are oriented in the first direction. Is produced through an orientation step of orienting in a second direction orthogonal to and a molding step of solidifying the polymer composition to form a shaped body after magnetic field orientation. According to this configuration, first, a polymer composition is prepared in which at least two types of fibers Fp and Fn that are respectively oriented in the first direction and the second direction are blended. And after inject | pouring a liquid polymer composition into a metal mold | die, a magnetic field is applied to the polymer composition in a metal mold | die. For this reason, unlike conventional methods in which a fiber cloth is placed in a mold, a polymer composition containing fibers is injected into the mold, and then a magnetic field is applied to the polymer composition in the mold, the polymer composition Involvement of bubbles in the object and unevenness of the fiber cloth are eliminated, and the number of processes can be reduced. Therefore, variation in quality characteristics can be suppressed and production can be performed efficiently.

Next, the polymer composite material molded body of the present invention will be described more specifically with reference to Examples and Comparative Examples.
Example 1
In Example 1, a polymer composite material compact was produced according to the following steps. Specifically, carbon fiber (“GRANOC Milled Fiber XN-100” manufactured by Nippon Graphite Fiber Co., Ltd.) is used with respect to 100 parts by weight of unsaturated polyester resin (“Epolac G157” manufactured by Nippon Shokubai Co., Ltd.) as the polymer material. 50 parts by weight of an average length of 50 μm and 10 parts by weight of polyethylene fiber (“Dyneema (registered trademark)” manufactured by Toyobo Co., Ltd., 20 μm in diameter and 0.5 to 1 mm in length) were mixed. Then, using a stirrer, a liquid polymer composition was prepared by mixing while defoaming under reduced pressure.

Next, the above polymer composition was poured into the molding recess, and the mold was closed, and then vibration was applied by a vibration generator to randomize the fibers of the polymer composition. Then, the mold was moved and a magnetic field with a magnetic flux density of 10 Tesla was applied. As the mold, an aluminum mold having a molding recess coated with a fluororesin was used. In order to obtain a plate-shaped polymer composite material molded body, each dimension of the molding recess was set to 50 mm in length, 50 mm in width, and 5 mm in depth. In addition, a superconducting magnet was used to obtain a magnetic field of 10 Tesla, and a mold was installed so that the magnetic lines of force passed in the depth direction of the molding recess. Then, by applying a magnetic field, the carbon fibers in the polymer composition were aligned in parallel with the magnetic lines of force, and the polyethylene fibers were aligned in a direction perpendicular to the magnetic lines of force. Thereafter, the polymer material was solidified by heating to produce a plate-like polymer composite material molded body.
(Example 2)
In Example 2, an average length of carbon fiber (“GRANOC milled fiber XN-100” manufactured by Nippon Graphite Fiber Co., Ltd.) is set to 100 μm, and polyethylene fiber (“Dyneema (registered trademark)” diameter 20 μm manufactured by Toyobo Co., Ltd.) is used. A plate-shaped polymer composite molded body was produced through the same steps as in Example 1 except that one having a length of 0.8 to 1.4 mm was used.
(Example 3)
In Example 3, an average length of carbon fibers (“GRANOC milled fiber XN-100” manufactured by Nippon Graphite Fiber Co., Ltd.) is 250 μm, and polyethylene fibers (“Dyneema (registered trademark)” diameter 20 μm manufactured by Toyobo Co., Ltd.) are used. A plate-shaped polymer composite material was produced through the same steps as in Example 1 except that the length was 1.5 to 2.0 mm.
(Comparative Example 1)
The polymer composite material molded body of Comparative Example 1 was produced through the same steps as the polymer composite material molded body of Example 1 except that no magnetic field was applied. In the polymer composite molded body of Comparative Example 1, since the magnetic field was not applied after the vibration was applied by the vibration generator, the carbon fiber and the polyethylene fiber in the polymer composition remained randomly dispersed.
(Comparative Example 2)
In Comparative Example 2, an average length of carbon fiber (“GRANOC Milled Fiber XN-100” manufactured by Nippon Graphite Fiber Co., Ltd.) with respect to 100 parts by weight of an unsaturated polyester resin (“Epolac G157” manufactured by Nippon Shokubai Co., Ltd.) as the polymer material. 50 μm) was mixed with 50 parts by weight. Then, using a stirrer, a liquid polymer composition was prepared by mixing while defoaming under reduced pressure.

Next, one polyethylene fiber cloth (“Cybermesh (registered trademark)” basis weight 94 g / m ² , thickness 0.5 mm, manufactured by Toyobo Co., Ltd.) was placed in the molding recess of the mold used in Example 1. The polyethylene fiber cloth was disposed on the bottom surface of the molding recess in order to be parallel to the surface of the plate-shaped polymer composite material molding. Subsequently, the above polymer composition was poured into the molding recess, and the polymer composition was impregnated in the gaps between the polyethylene fiber cloths. Further, another polyethylene fiber cloth was laminated on the polymer composition in the molding recess from above, and the polymer composition was impregnated in another polyethylene fiber cloth. The carbon fiber was oriented parallel to the lines of magnetic force by applying a magnetic field at a magnetic flux density of 10 Tesla. Thereafter, the polymer material was solidified by heating to produce a plate-like polymer composite material molded body. In the polymer composite material molded body of Comparative Example 2, the carbon fibers were oriented in the direction perpendicular to the surface of the polyethylene fiber cloth.

Table 1 shows the linear expansion coefficients in the thickness direction and the surface direction, and the thermal conductivity in the thickness direction and the surface direction, respectively, in the polymer composite material, together with the magnetic flux density of the magnetic field.
<Linear thermal expansion coefficient>
In Examples and Comparative Examples, the linear expansion coefficient was measured according to JIS K7197. Specifically, 20 test pieces for evaluation having a thickness of 5 mm, a length of 5 mm, and a width of 5 mm were prepared from the obtained polymer composite material compact, and the linear expansion coefficient of each test piece was measured. The linear thermal expansion coefficient shown in Table 1 is an average value obtained from 20 pieces of data, and the standard deviation indicates an index of data variation.
<Thermal conductivity>
In Examples and Comparative Examples, the thermal conductivity was measured using a laser flash method thermophysical property measuring apparatus “LFA-502” manufactured by Kyoto Electronics Industry Co., Ltd. Specifically, an evaluation test piece having a thickness of 2 mm and a diameter of 10 mm was prepared from the obtained polymer composite material molded body, and the thermal conductivity of the evaluation test piece was measured.

表１の結果から、実施例１の高分子複合材料成形体では、炭素繊維が厚み方向に配向され、ポリエチレン繊維が面方向に配向されたため、厚み方向、面方向ともに熱膨張が抑えられていた。また、実施例１では、炭素繊維が厚み方向に配向されたため、厚み方向の熱伝導率は２．４Ｗ／ｍ・Ｋ以上であり、面方向の熱伝導率の３倍以上であった。すなわち、実施例１の成形体では、熱膨張性の等方性及び熱伝導性の異方性の両方を同時に実現できた。

From the result of Table 1, in the polymer composite material molded body of Example 1, since the carbon fibers were oriented in the thickness direction and the polyethylene fibers were oriented in the plane direction, thermal expansion was suppressed in both the thickness direction and the plane direction. . In Example 1, since the carbon fibers were oriented in the thickness direction, the thermal conductivity in the thickness direction was 2.4 W / m · K or more, which was three times or more the thermal conductivity in the plane direction. That is, in the molded body of Example 1, it was possible to simultaneously realize both the thermal expansion isotropic property and the thermal conductivity anisotropy.

  Moreover, in the polymer composite material molded body of Example 1, the standard deviations of the linear expansion coefficients in the thickness direction and the surface direction were both 0.2 or less. Since the carbon fiber used in Example 1 has a high magnetic field orientation and the polyethylene fiber has a relatively weak magnetic field orientation, when carbon fibers having a long fiber length are used, the carbon fibers collide with the polyethylene fiber during the magnetic field orientation. There is a risk. In that respect, in Example 1, since the fiber lengths of the carbon fiber and the polyethylene fiber are both 2 mm or less, it is presumed that the fibers were smoothly oriented in the thickness direction and the surface direction. Therefore, from the results of Example 1, it was confirmed that according to the manufacturing method of the present embodiment, variation in quality can be suppressed and productivity can be increased.

  Also in the polymer composite material molded bodies of Examples 2 and 3, since the carbon fibers were oriented in the thickness direction and the polyethylene fibers were oriented in the plane direction, thermal expansion was suppressed in both the thickness direction and the plane direction. Also in Examples 2 and 3, since the carbon fibers were oriented in the thickness direction, the thermal conductivity in the thickness direction was 2.6 W / m · K or more, which was more than 3 times the thermal conductivity in the plane direction. . That is, in the molded bodies of Examples 2 and 3, the fiber lengths of the carbon fiber and the polyethylene fiber are longer than those of Example 1, but since both are 2 mm or less, the same results as in Example 1 are obtained. It was. That is, in the molded bodies of Examples 2 and 3, both the thermal expansion isotropic property and the thermal conductivity anisotropy were realized at the same time.

  In the molded article of the polymer composite material of Comparative Example 1, both the carbon fiber and the polyethylene fiber were randomly dispersed, so that the thermal expansion was isotropic. Moreover, in the comparative example 1, since the carbon fiber was not oriented in the thickness direction, the thermal conductivity in the thickness direction was less than 0.9 W / m · K.

  In the polymer composite material molded body of Comparative Example 2, the standard deviation of the linear expansion coefficient in the thickness direction and the linear expansion coefficient in the plane direction was large, and the linear expansion coefficient varied. As a result of observing a cross section of the polymer composite material molded body of Comparative Example 2, there was a bias in the position of the polyethylene fiber cloth laminated inside the polymer composite material molded body. From this, in Comparative Example 2, it was not possible to stably produce a polymer composite material molded body having a small linear expansion coefficient and isotropically controlled. Furthermore, since a process of placing the fiber cloth in the mold in advance and a process of casting the liquid polymer material in the mold are required, the molding cycle is longer than that of the method of Example 1. .

  M: polymer material, Fp: first fiber, Fn: second fiber.

Claims (6)

In a polymer composite molded body containing at least two kinds of fibers in a polymer material,
The polymer material contains a first fiber having a positive anisotropic magnetic susceptibility and a second fiber having a negative anisotropic magnetic susceptibility, and the first fiber. Are oriented in a first direction, and the second fibers are oriented in a second direction orthogonal to the first direction. In the polymer composite molded article according to claim 1,
A polymer composite material molded body, wherein the first and second fibers have a fiber length of 2 mm or less. In the polymer material molded body according to claim 1 or 2,
The polymer composite material molded body, wherein the first fiber is selected from the group consisting of carbon fiber, aramid fiber, polybenzazole fiber, polyimide fiber, polyphenylene sulfide fiber, and halogenated polyolefin fiber. In the polymeric material molded object according to any one of claims 1 to 3,
The polymer composite material molded body, wherein the second fiber is selected from the group consisting of polyethylene fiber, polylactic acid fiber, and polyoxymethylene fiber. A method for producing a polymer composite molded article,
A liquid polymer composition is prepared by blending a first fiber having a positive anisotropic magnetic susceptibility and a second fiber having a negative anisotropic magnetic susceptibility into a polymer material. A step of preparing;
After injecting the polymer composition into a mold, by applying a magnetic field to the polymer composition in the mold, the first fibers are oriented in a first direction, and the second fibers are Orienting in a second direction orthogonal to the first direction;
And a step of solidifying the polymer composition to form a molded body after magnetic field orientation. In the manufacturing method of the polymeric composite material molded object according to claim 5,
A method for producing a molded article of a polymer composite material, wherein the first and second fibers have a fiber length of 2 mm or less.

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