JP2007217587A - Method for producing polymer molding and polymer molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polymer molding, which improves external surface smoothness while orientating a polymer chain and to obtain a polymer molding easily exhibiting thermal conductivity performance based on the orientation of the polymer chain. <P>SOLUTION: The polymer film as a polymer molding is produced from a polymer solution developing an optical anisotropy. The method for producing a polymer film comprises an orientation process for orientating the polymer chain of a polymer base, obtained by forming a polymer solution into a filmy state, in a fixed direction and a coagulation process for coagulating the polymer orientated by the orientation process to give a polymer coagulated material and a curing process for curing the polymer coagulated material by drying the polymer coagulated material. Porous plates 24 are stuck fast to the polymer coagulated material 13 in the curing process. Since the porous plates 24 have air permeability, the polymer coagulated material 13 is dried through the porous plates 24 in the curing process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a polymer molded body in which polymer chains are aligned and a polymer molded body.

A polymer molded body in which polymer chains are aligned is obtained by applying a magnetic field or an electric field to a polymer solution having optical anisotropy (see Patent Document 1). That is, in a polymer solution to which a magnetic field or an electric field is applied, the molecular chains of the polymer in the solution are highly oriented. The polymer molded body is obtained by solidifying the polymer solution to obtain a polymer coagulated body, and then curing the polymer coagulated body. In such a polymer molded body, anisotropy develops with respect to characteristics typified by thermal properties and mechanical properties as the polymer chain is oriented.
JP 2004-107621 A

  The cohesive force of the polymer chain in the polymer solidified body as described above is stronger in the direction orthogonal to the direction than the direction in which the polymer chain is oriented. For this reason, the polymer solidified body is cured with contraction in a direction orthogonal to the direction in which the polymer is oriented. As a result, the smoothness of the outer surface of the resulting polymer molded product tends to decrease. In particular, in a polymer solidified body in which polymer chains are highly oriented by a magnetic field or an electric field, when the polymer solidified body is cured to obtain a polymer molded body, the degree of shrinkage is increased, resulting in a high yield. Smoothness on the outer surface of the molecular compact tends to be lowered. For example, when the polymer molded body is interposed between the heat generating body and the heat radiating body in order to increase the heat conduction from the heat generating body to the heat radiating body, such a decrease in smoothness is high. The adhesion of the molecular compact is reduced. Such a decrease in adhesion increases the thermal resistance from the heat generating element to the heat radiating element, and as a result, it becomes difficult to exhibit the inherent heat conductivity of the polymer molded body.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a method for producing a polymer molded body capable of improving the smoothness of an outer surface while orienting polymer chains, and a polymer. An object of the present invention is to provide a polymer molded body that can easily exhibit the heat conduction performance based on the orientation of the chain.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a polymer chain in the polymer solution is formed by applying a magnetic field or an electric field to the polymer solution exhibiting optical anisotropy. An alignment step for aligning in a certain direction, a solidification step for solidifying the polymer aligned in the alignment step to obtain a polymer solidified body, and a polymer molded body by curing the polymer solidified body And a curing step for obtaining a polymer molded body, wherein the polymer molded body is manufactured from the polymer solution, wherein the curing step has air permeability and the polymer coagulated body. The gist of the invention is that the polymer solidified body is dried through the pressure body in a state where the pressure body to be pressed is disposed in close contact with the polymer solidified body.

The invention according to claim 2 is summarized in that, in the method for producing a polymer molded body according to claim 1, the pressure applied in the curing step is 0.49 MPa to 9.8 MPa.
Invention of Claim 3 makes it a summary for the manufacturing method of the polymer molded object of Claim 1 or Claim 2 that the said pressurization body is a porous board.

  Invention of Claim 4 is a manufacturing method of the polymer molded object as described in any one of Claims 1-3. WHEREIN: In the said hardening process, the said polymer solidified body is heated, To do.

  According to a fifth aspect of the present invention, in the method for producing a polymer molded body according to any one of the first to fourth aspects, the polymer solution is formed into a film shape, and the curing step includes: The area of the surface orthogonal to the thickness direction of the polymer solidified body subjected to the curing step is A1, and the area of the surface orthogonal to the thickness direction of the polymer molded body obtained by the curing step is A2. The gist is that the shrinkage remaining rate R (%) = A2 / A1 × 100 shown is performed so as to satisfy the relationship of shrinkage remaining rate R (%) ≧ 50 (%).

  According to a sixth aspect of the present invention, in the method for producing a polymer molded body according to any one of the first to fifth aspects, in the curing step, the polymer solidified body is sandwiched between the pressure bodies. The gist is to do.

  The polymer molded body of the invention according to claim 7 is a polymer molded body obtained by the method for producing a polymer molded body according to any one of claims 1 to 6, wherein the polymer The gist is that the polymer in the solution is a lyotropic liquid crystal polymer.

  The invention according to claim 8 is the polymer molded body according to claim 7, wherein the lyotropic liquid crystal polymer is at least selected from polyparaphenylene terephthalamide, polybenzimide, polyparaphenylene, and polybenzazole. The gist is that it is a kind.

  According to the method for producing a polymer molded body of the present invention, the smoothness of the outer surface of the polymer molded body can be improved while orienting the polymer chain. According to the polymer molded body of the present invention, it is easy to exhibit the heat conduction performance based on the orientation of the polymer chain.

Hereinafter, an embodiment in which the present invention is applied to a method for producing a polymer film will be described in detail.
The polymer film 11 as a polymer molded body shown in FIG. 5 is manufactured from a polymer solution exhibiting optical anisotropy. The method for producing the polymer film 11 includes a polymer substrate obtained by forming a polymer solution into a film, an alignment step of aligning polymer chains of the polymer substrate in a certain direction, and the alignment step. And a coagulation step for obtaining a polymer coagulum by coagulating the oriented polymer. Furthermore, this manufacturing method includes a curing step of curing the polymer coagulated product by drying the polymer coagulated product. This curing step is performed in a state where a pressurizing body that pressurizes the polymer coagulated body is disposed in close contact with the polymer coagulated body. And since this pressurization body has air permeability, drying through a pressurization body of a polymer solidification object is performed in a hardening process.

<Polymer solution>
As the polymer of the polymer solution, a polymer that exhibits optical anisotropy in the polymer solution is used. That is, as this polymer, a lyotropic liquid crystal polymer is preferably used. The polymer solution can be prepared by dissolving the lyotropic liquid crystal polymer in a solvent so that the optical anisotropy is obtained. The optical anisotropy of the polymer solution is manifested by the presence of the polymer in the solution with a certain regularity. The lyotropic liquid crystal polymer is not particularly limited, and for example, at least one selected from polyparaphenylene terephthalamide, polybenzimide, polyparaphenylene, and polybenzazole is preferable.

  The polybenzazole which is suitable as a polymer of this polymer solution will be described in detail. Specific examples of the polybenzazole include a polymer containing at least one selected from polybenzoxazole (PBO), polybenzothiazole (PBT), and polybenzimidazole (PBI). Examples of such polybenzazoles include homopolymers made of any one of PBO, PBT, and PBI, and blend polymers and copolymers (block copolymers or random copolymers) containing at least two selected from PBO, PBT, and PBI. Including.

  PBO refers to a polymer composed of a repeating unit having at least one oxazole ring bonded to an aromatic group, and includes, for example, poly (phenylenebenzobisoxazole). PBT refers to a polymer composed of a repeating unit having at least one thiazole ring bonded to an aromatic group, and includes, for example, poly (phenylenebenzobisthiazole). PBI refers to a polymer composed of a repeating unit having at least one imidazole ring bonded to an aromatic group, and includes, for example, poly (phenylenebenzbisimidazole).

  Specifically, the polybenzazole includes polybenzazole having at least one repeating unit represented by the following general formulas (1) to (4).

（但し、上記式（１）〜（４）中のＸはそれぞれ独立してイオウ原子、酸素原子又はイミノ基を表し、上記式（１）及び（２）中のＡｒ_１及びＡｒ_２は芳香族炭化水素基をそれぞれ表し、ｎは１０〜５００の整数である。）
Ａｒ_１の具体例としては、下記一般式（Ｉ）〜（ＩＶ）に示される芳香族炭化水素基が挙げられる。

(However, X in the above formulas (1) to (4) each independently represents a sulfur atom, an oxygen atom or an imino group, and Ar ₁ and Ar ₂ in the above formulas (1) and (2) are aromatic. Each represents a hydrocarbon group, and n is an integer of 10 to 500.)
Specific examples of Ar ₁ include aromatic hydrocarbon groups represented by the following general formulas (I) to (IV).

Ａｒ_２の具体例としては、下記一般式（Ｖ）〜（ＶＩＩＩ）に示される芳香族炭化水素基が挙げられる。

Specific examples of Ar ₂ include aromatic hydrocarbon groups represented by the following general formulas (V) to (VIII).

上記一般式（Ｉ）〜（ＶＩＩＩ）中のＺは、それぞれ酸素原子、イオウ原子、ＳＯ_２、ＣＯ、ＣＨ_２、Ｃ（ＣＨ_３）_２、ＣＦ_２又はＣ（ＣＦ_３）_２のいずれかを表すか、または、隣り合うベンゼン環中の炭素同士の直接結合を表す。また、上記一般式（Ｉ）〜（ＶＩＩＩ）中のベンゼン環において、各炭素原子と結合している水素原子は低級アルキル基、低級アルコキシル基、ハロゲン原子又はトリフルオロメチル等のハロゲン化アルキル基、ニトロ基、スルホン酸基、ホスホン酸基等に置換されていてもよい。この置換反応は、重縮合反応前に対応する上記部分を含む原材料において行われていてもよいし、または重縮合反応後のポリベンズアゾールの対応する部分について行われていてもよい。

Z in the general formulas (I) to (VIII) represents an oxygen atom, a sulfur atom, SO ₂ , CO, CH ₂ , C (CH ₃ ) ₂ , CF _2, or C (CF ₃ ) ₂ , respectively. Or a direct bond between carbons in adjacent benzene rings. In the benzene rings in the above general formulas (I) to (VIII), the hydrogen atom bonded to each carbon atom is a lower alkyl group, a lower alkoxyl group, a halogen atom or a halogenated alkyl group such as trifluoromethyl, It may be substituted with a nitro group, a sulfonic acid group, a phosphonic acid group, or the like. This substitution reaction may be performed on the raw material containing the corresponding portion before the polycondensation reaction, or may be performed on the corresponding portion of the polybenzazole after the polycondensation reaction.

  In addition to the repeating units represented by the above general formulas (1) to (4), the polybenzazole may contain a repeating unit having an unreacted open chain in the process of synthesizing polybenzazole. Such an unreacted open chain moiety is represented by, for example, the following formulas (IX) and (X).

上述したようなポリベンズアゾールの中でも、上記一般式（１）及び（２）の少なくとも一方の繰り返し単位を有するポリベンズアゾールであって、前記式中においてＸが酸素原子であるとともに、Ａｒ_１及びＡｒ_２は一般式（Ｉ）〜（ＶＩＩＩ）のＺが酸素原子又は直接結合を示すポリベンズアゾールを採用した場合には、高分子鎖がより直線的となる。このため、このような高分子鎖を配向工程によって配向させることにより、一層高い熱伝導性が発揮される高分子フィルム１１を得ることができる。

Among the polybenzazoles described above, a polybenzazole having at least one repeating unit of the above general formulas (1) and (2), wherein X is an oxygen atom, Ar ₁ and When Ar ₂ employs polybenzazole in which Z in the general formulas (I) to (VIII) represents an oxygen atom or a direct bond, the polymer chain becomes more linear. For this reason, the polymer film 11 which exhibits higher thermal conductivity can be obtained by orienting such polymer chains in the orientation process.

  The intrinsic viscosity of polybenzazole is measured by an Ostwald viscometer using methanesulfonic acid as a solvent at 25 ° C. (according to American Society for Testing and Materials standard ASTM D2857-95), preferably 0.5-30 dl / g, more preferably Is 0.5 to 20 dl / g, more preferably 0.5 to 15 dl / g. When the intrinsic viscosity of the polybenzazole is less than 0.5 dl / g, the molecular weight of the polybenzazole is lowered, and as a result, the mechanical strength of the resulting polymer film 11 may not be sufficiently obtained. On the other hand, when the intrinsic viscosity of polybenzazole exceeds 30 dl / g, when a polybenzazole solution is prepared from the polybenzazole, the viscosity of the solution becomes too high, and the molecular chain of polybenzazole is difficult to be oriented. There is a risk.

  The solvent for preparing the polymer solution may be appropriately selected depending on the type of polymer. For example, when polyparaphenylene terephthalamide is employed as the polymer, concentrated sulfuric acid can be used. For example, when polybenzazole is employed as the polymer, aprotic polar solvents such as N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, hexamethylphosphortriamide, etc. And polyphosphoric acid, methanesulfonic acid, cresol, and high-concentration sulfuric acid, and at least one of polyphosphoric acid and methanesulfonic acid is preferably used, and at least polyphosphoric acid is more preferably used.

  Such a solvent may be used independently and may be used in mixture of 2 or more types. The solvent may contain a Lewis acid such as lithium bromide, lithium chloride, or aluminum chloride from the viewpoint of improving the solubility of the polymer.

  A known stirrer can be used for the operation of dissolving the polymer in the solvent. The polymer to be subjected to the dissolving operation may be purified by a conventional technique such as reprecipitation or filtration before performing the dissolving operation.

  The concentration of the polymer in the polymer solution is appropriately set according to the expression of the liquid crystal phase, the solubility of the polymer, the viscosity of the polymer solution, and the like. The concentration of the polymer in the polymer solution is preferably 2 to 30% by mass, more preferably 5 to 25% by mass. If the concentration of the polymer is less than 2% by mass, the liquid crystal phase may be hardly expressed. On the other hand, if the polymer concentration exceeds 30% by mass, the viscosity of the polymer solution may be too high. That is, by setting the concentration of the polymer to 2 to 30% by mass, the polymer chain has a viscosity suitable for the alignment of the polymer chain and the liquid crystal phase is sufficiently expressed. Can be increased.

  Polymer solutions include glass fiber and other reinforcing materials, various fillers, pigments, dyes, fluorescent brighteners, dispersants, stabilizers, UV absorbers, antistatic agents, antioxidants, thermal stabilizers, lubricants, You may mix | blend a plasticizer etc. in the range with which the effect of this invention is acquired.

  A method for obtaining a polymer substrate by molding a polymer solution is not particularly limited, a method for injecting a polymer solution into a mold, a method for casting a polymer solution from a die, for example, a slit die, onto a molding substrate And a method of applying a polymer solution onto a molded substrate by a casting method or the like. The molding substrate used for molding such a polymer solution is not particularly limited. However, when the polymer substrate is molded into a long film, a closed loop endless belt, endless drum or An endless film is preferably used. Moreover, it is also possible to use plate-shaped objects, such as a glass plate and a resin film, as a shaping | molding base material. Furthermore, the forming base material may be made of a metal, and as the metal, stainless steel, hastelloy alloy, tantalum, aluminum or the like is suitable. In addition, the polymer solution is cast from the slit die onto the lower molding substrate, and another molding substrate is stacked on the cast polymer solution, so that the polymer solution is placed between the pair of molding substrates. By sandwiching the film, a film-like polymer substrate having a certain thickness can be easily formed.

  In this embodiment, as shown in FIG. 1, a pair of upper and lower molding resin films 21 is used as a molding substrate. These moldable resin films 21 are subjected to fluorine coating treatment on the surface thereof, so that the releasability of the polymer substrate 12 with respect to the moldable resin film 21 is improved. The polymer substrate 12 is formed into a film having a certain thickness by sandwiching the polymer solution between the pair of molding resin films 21.

  The expression of the liquid crystal phase (optical anisotropy) of the polymer substrate (polymer solution) depends on the concentration of the polymer in the polymer substrate and the temperature of the polymer substrate. Therefore, in order to develop a liquid crystal phase in the polymer substrate, the temperature of the polymer substrate may be adjusted so that the temperature of the polymer substrate falls within a predetermined temperature range. When the liquid crystal phase is developed by heating the polymer substrate, the temperature of the polymer substrate is raised to an isotropic liquid by raising the temperature of the polymer substrate to a temperature at which the liquid crystal phase is not developed. It is preferable to gradually lower the temperature of the molecular substrate. Thereby, since the growth of the liquid crystal phase is promoted, the alignment of the polymer chains in the alignment step is efficiently performed. Moreover, you may use together such temperature rising and temperature falling sequentially.

  What is necessary is just to set the temperature of the polymer base | substrate which expresses a liquid crystal phase suitably according to the kind of lyotropic liquid crystal polymer, for example, it sets to the range of 20-250 degreeC. For example, when polybenzazole is adopted as the lyotropic liquid crystal polymer, the temperature is preferably 20 to 200 ° C, more preferably 40 to 150 ° C. Examples of the heating means include a method using humidified air as a heating medium, a method of irradiating ultraviolet rays from an ultraviolet lamp, and a method using dielectric heating.

<Orientation process>
The polymer substrate exhibiting the liquid crystal phase (optical anisotropy) in this way is subjected to an alignment step. In the alignment step, by applying a magnetic field or an electric field to the polymer substrate, the polymer chains are aligned in a certain direction in the polymer substrate. That is, the polymer chain is aligned along the direction of the magnetic field lines and the electric field, and the characteristics such as thermal conductivity in the direction along the alignment of the polymer chain are enhanced. Since the polymer substrate in this alignment step expresses a liquid crystal phase, the polymer chain in the polymer substrate 12 has order. The polymer chains having such order are efficiently oriented by applying a magnetic field or an electric field.

  The magnetic field can be applied by magnetic field generating means such as a permanent magnet, an electromagnet, or a superconducting magnet. The electric field can be applied by an electric field generating means including an electrode, a slide transformer or the like. In this orientation step, it is preferable to apply a magnetic field to the polymer substrate so that the magnetic lines are parallel to the desired direction in order to orient the polymer chain in the desired direction. According to such orientation by applying a magnetic field, the polymer chain can be oriented in any direction, such as the direction intersecting the surface of the polymer substrate, not only in the direction along the surface shape of the polymer substrate. Easy. The magnetic flux density of the magnetic field is preferably 1 to 30 Tesla (T), more preferably 2 to 25 T, and still more preferably 3 to 20 T. When the magnetic flux density is less than 1T, the polymer chains may not be efficiently aligned. On the other hand, in order to obtain a magnetic flux density exceeding 30 T, the cost of the magnetic field generating means increases.

  In the present embodiment, as shown in FIG. 2, a polymer is applied by applying a magnetic field to the polymer substrate 12 using a pair of upper and lower magnets 22 so that the magnetic force lines 23 are along the thickness direction of the polymer substrate 12. The polymer chains are oriented in the thickness direction of the substrate 12. Thus, in the polymer substrate 12 to which a magnetic field is applied, the polymer chain is oriented in the thickness direction (the Z-axis direction of the polymer film 11 shown in FIG. 5). The thermal conductivity in the thickness direction is improved. As shown in FIG. 3, if a pair of left and right magnets 22 are used to align the magnetic lines of force 23 in the direction along the front and back surfaces of the polymer substrate 12, the polymer in the direction along the front and back surfaces of the polymer substrate 12. The chains can be oriented.

<Coagulation process>
The polymer substrate on which the polymer is oriented by the orientation process is subjected to a coagulation process. This coagulation step is a step of obtaining a polymer coagulated body by coagulating the polymer of the polymer substrate (polymer solution). In this coagulation step, the polymer is evaporated by a method of evaporating the solvent and the coagulation liquid. A method of precipitation can be applied. As this coagulation step, a heating apparatus for evaporating the solvent, an apparatus for recovering the evaporated solvent, and the like can be omitted. Therefore, a method of precipitating the polymer with the coagulating liquid is preferable. As the coagulation liquid, there can be used a polymer poor solvent or a liquid insoluble in the polymer while being compatible with the polymer solvent. By bringing the coagulating liquid into contact with the polymer substrate 12, the polymer substrate has a low solubility in the polymer solvent. Due to the decrease in the solubility of the polymer, the polymer substrate is solidified by the precipitation of the polymer. When a strong acid such as polyphosphoric acid is used as a polymer solvent, such a strong acid is diluted by using a coagulation liquid, so that the safety of handling the solvent is improved and the post-treatment of the solvent is performed. It becomes easy.

  In the solidification step of this embodiment, after removing at least one of the molding resin films 21 shown in FIG. 1, the solidification solution is immersed in the solidification solution to bring the solidification solution into contact with the polymer substrate 12 in which the alignment step is completed. Yes.

  What is necessary is just to select a coagulation liquid suitably according to the kind of polymer | macromolecule. Examples of the coagulation liquid include water, an aqueous acid solution such as a phosphoric acid aqueous solution and a sulfuric acid aqueous solution, an alkaline aqueous solution such as a sodium hydroxide aqueous solution, alcohols such as methanol and ethanol, and a water-soluble organic solvent such as acetone and ethylene glycol. . The coagulation liquid may be composed of a single component or a mixed liquid composed of two or more components. In this coagulation step, it is preferable to coagulate the polymer while applying a magnetic field or electric field in order to maintain the orientation of the polymer chain. From the viewpoint that the diffusion of the coagulation liquid with respect to the polymer solvent is gentle and the smoothness of the front and back surfaces of the obtained polymer coagulation body is easily secured, the coagulation liquid is a 10 to 70% by mass phosphoric acid aqueous solution or a lower alcohol. Is preferably used.

  The temperature of the coagulation liquid is preferably −60 to + 60 ° C., more preferably −30 to + 30 ° C., and still more preferably −20 to + 20 ° C. When the temperature of the coagulation liquid exceeds 60 ° C., it becomes difficult to ensure the smoothness of the front and back surfaces of the polymer coagulated body, and the resulting polymer has a density difference between the front and back surfaces of the polymer coagulated body. There exists a possibility that the physical property of the film 11 may become unstable. On the other hand, when the temperature of the coagulation liquid is less than −60 ° C., the physical properties of the resulting polymer film 11 may be adversely affected, and the coagulation rate of the polymer may be reduced, which may reduce productivity.

  The polymer solidified body is preferably subjected to a washing treatment before being subjected to a curing step which is a subsequent step. This cleaning treatment can be performed, for example, by passing a polymer coagulation body arranged on the molding substrate through the cleaning liquid or spraying the polymer coagulation body with the cleaning liquid. As the cleaning liquid, water is usually used, but hot water may be used if necessary. For example, when an acid is used as a polymer solvent, the acid remains in the polymer coagulum. In this case, the polymer coagulum is neutralized and washed with an aqueous alkali solution such as sodium hydroxide, potassium hydroxide, or lithium hydroxide, and then the acid contained in the polymer coagulum is quickly removed by washing treatment. can do. In such a cleaning process, impurities contained in the polymer coagulum are removed. Impurities in the polymer solidified body are acids and bases that form polymer structural units, and inorganic salts generated by neutralization washing. Such impurities deteriorate the polymer solidified body in the subsequent step of the solidification step ( Decomposition). Therefore, when the content of impurities in the polymer solidified body increases, the properties of the resulting polymer film 11 may be impaired. For this reason, it is preferable that the impurity contained in the polymer solidified body after the washing treatment is 500 ppm or less on a mass basis.

<Curing process>
The polymer solidified body obtained in the coagulation step is subjected to a curing step. This curing step is performed in a state where the polymer solidified body is pressurized by the pressure body. Since the polymer solidified body is pressurized by a pressure body arranged in close contact with each other, the polymer solidified body is dried in a state in which its shape is maintained. Furthermore, since this pressurization body has air permeability, the polymer coagulation body is dried by the vapor generated from the polymer coagulation body passing through the pressurization body. That is, when the polymer solidified body is dried, the polymer solidified body is also included in the portion where the polymer solidified body is covered with the pressurized body in addition to the exposed portion of the polymer solidified body. The solvent to be evaporated is volatilized. Accordingly, since the polymer coagulated body is dried over the whole, it is possible to suppress partial variation in the drying rate of the polymer coagulated body. As a result, the polymer solidified body can be dried while suppressing the shrinkage of the polymer solidified body.

The pressure body used in this curing step is not particularly limited as long as it has air permeability. Examples of the material of the pressurized body include porous ceramics such as porous alumina, porous silicon nitride, and porous silicon carbide, porous metal, porous glass, and porous resin. Examples of the shape of the pressure member include a plate shape and a block shape. Although the thickness of a pressurization body is not specifically limited, The thing of about 1-20 mm is used suitably from a viewpoint of handleability or durability. Among these pressure bodies, it is easy to impart the smoothness of the surface of the pressure body and the breathability of the pressure body, and the strength that can withstand the pressure of the pressure is easily obtained. A porous plate, more preferably a porous ceramic plate or a porous metal plate. The metal forming the porous metal plate is not particularly limited, but it is preferably at least one selected from aluminum, stainless steel, hastelloy alloy and tantalum in view of chemical resistance. Also,
Specifically, “Pocerax (registered trademark) I” manufactured by Shinto Kogyo Co., Ltd. or the like can be used as the porous ceramic plate. Moreover, as a specific example of a porous metal plate, “Pocerax (registered trademark) II” manufactured by Shinto Kogyo Co., Ltd., porous aluminum “POROUS” manufactured by Hadano Kogyo Co., Ltd., or the like can be used.

  In the present embodiment, as shown in FIG. 4, a pair of upper and lower porous plates 24 is used as the pressurizing body. Then, the polymer coagulation body 13 is sandwiched between a pair of upper and lower porous plates 24 so that the polymer coagulation body 13 is dried through the porous plate 24 from both the upper and lower surfaces (front and back surfaces).

In the above-described pressurized body, the surface roughness of the contact surface that comes into contact with the surface of the polymer solidified body is preferably as small as possible from the viewpoint of forming the surface of the resulting polymer film 11 smoothly. The ten-point average roughness (Rz) defined in B 0601-1994 is preferably 0.05 to 10 μm. If the ten-point average roughness (Rz) is less than 0.05 μm, it may be difficult to produce a pressure body. On the other hand, if the ten-point average roughness (Rz) exceeds 10 μm, the resulting polymer film 11 may not be sufficiently smooth on the surface that has been in contact with the pressure member. The 10-point average roughness (Rz) defined in JIS B 0601-1994 is the 10-point average roughness (Rz _JIS94 ) calculated using the contour curve applied with the phase compensation wide-area filter.

  The average pore diameter (measurement method: visual observation with a microscope) of the pressurized body is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm, and still more preferably 1 to 20 μm. If this average pore size is less than 0.1 μm, the drying efficiency may not be sufficiently obtained. On the other hand, when the average pore diameter exceeds 100 μm, the resulting polymer film 11 may not have sufficient smoothness on the surface that has been in contact with the pressure member. The porosity (measurement method: “apparent porosity” of JIS R 2205 or JIS Z 2501 “open porosity”) of the pressurized body is preferably 10 to 60%, more preferably 15 to 25%. If the porosity is less than 10%, the drying efficiency may not be sufficiently obtained. On the other hand, if the porosity exceeds 60%, the resulting polymer film 11 may not have sufficient smoothness on the surface that has been in contact with the pressurized body.

The pressure at the time of pressurizing the polymer solidified body with the pressurized body is preferably 0.49 MPa (5 kgf / cm ² ) to 9.8 MPa (100 kgf / cm ² ), more preferably 0.49 MPa (5 kgf / cm ² ). It is ˜7.8 MPa (80 kgf / cm ² ), more preferably 0.98 MPa (10 kgf / cm ² ) to 7.8 MPa (80 kgf / cm ² ). When this pressure is less than 0.49 MPa, it is difficult to sufficiently suppress the shrinkage of the polymer coagulum, and the smoothness on the front and back surfaces of the resulting polymer film 11 may not be sufficiently improved. On the other hand, when the pressure exceeds 9.8 MPa, the polymer solidified body may be compressed, so that the orientation of the polymer chain may be lost. That is, by setting the pressure at the time of pressurizing the polymer solidified body to 0.49 MPa to 9.8 MPa, the orientation of the polymer chain can be suitably maintained, and the polymer solidified body shrinks in the curing step. Can be suitably suppressed.

  Well-known pressurizing means such as a clamp or a press can be used for pressurization of the polymer coagulated body by the pressurizing body. The pressurizing means may be configured to partially pressurize the pressurizing body, for example, so as to pressurize only the peripheral portion of the pressurizing body so as not to impair the breathability of the pressurizing body. .

  In this curing step, the polymer solidified body is preferably heated in order to improve the drying efficiency of the polymer solidified body. The heating temperature of the polymer solidified body is preferably 100 to 500 ° C, more preferably 100 to 400 ° C, and further preferably 100 to 200 ° C. If the heating temperature is less than 100 ° C, the drying efficiency may not be sufficiently improved. On the other hand, when this heating temperature exceeds 500 degreeC, there exists a possibility that a polymer solidified body may deteriorate (decompose) by the heating, and there exists a possibility of having a bad influence on the physical property of the polymer solidified body obtained.

  As shown in FIG. 4, in the curing step of curing the polymer solidified body 13 having the film shape of the present embodiment, the area of the surface orthogonal to the thickness direction of the polymer solidified body 13 is set to A1 and cured. The shrinkage residual rate R (%) indicated by A2 as the area of the surface orthogonal to the thickness direction of the polymer film 11 obtained by the process satisfies the following relationship.

Shrinkage residual rate R (%) = A2 / A1 × 100 ≧ 50 (%)
This shrinkage remaining rate R (%) is a value indicating the degree of shrinkage of the polymer coagulated body 13 in the drying step. In the curing step, the type of the pressure body in the curing step is selected so as to satisfy the relationship of the shrinkage residual rate R (%) ≧ 50 (%), the pressure applied to the polymer solidified body 13, the polymer The smoothness on the front and back surfaces of the polymer film 11 can be controlled with high accuracy by adjusting conditions such as the temperature of the solidified body 13. Furthermore, by satisfying the relationship of shrinkage remaining rate R (%) ≧ 50 (%), it is possible to suppress the polymer of the polymer coagulated body 13 from becoming excessively dense. The flexibility (softness) and bending strength can be further increased.

  If the shrinkage residual ratio R (%) is less than 50 (%), the smoothness on the front and back surfaces of the polymer film 11 may not be sufficiently obtained. The area A1 in this residual shrinkage rate R (%) indicates the surface area of the polymer coagulated body 13 in a state where it is not pressurized by the pressure body. Area A2 represents the surface area of the polymer film 11 that was allowed to stand for 24 hours in an environment at a temperature of 25 ° C. and a relative humidity of 50% after the curing step was completed. The area A1 is the surface area of the surface in contact with the pressure body, and the area A2 is the surface area of the surface in contact with the pressure body. The upper limit of the shrinkage remaining rate R (%) is not particularly limited, but is less than 100 (%) in consideration of the properties of the polymer solidified body 13.

<Polymer molded product>
The polymer film 11 as a polymer molded body has excellent thermal conductivity in the thickness direction because the polymer chains are oriented in the thickness direction. The orientation of the polymer chain in the polymer film 11 is determined by a method of measuring optical anisotropy (phase difference, birefringence) using two polarizers or a polarizing microscope, or an analysis method using a polarized infrared absorption spectrum. It is confirmed. Furthermore, it is also confirmed by a polarized Raman spectrum method, a method by X-ray diffraction analysis, a method by electron beam diffraction analysis, a method of observation by an electron microscope, and the like.

  The degree of orientation A of the polymer chain of the polymer film 11 is obtained by performing wide-angle X-ray diffraction measurement (transmission) of the polymer film 11. This wide-angle X-ray diffraction measurement is performed when particles (polymer chains) existing in the polymer film 11 are oriented by irradiating the polymer film 11 with X-rays using a wide-angle X-ray diffractometer. Shows a concentric arc-shaped diffraction pattern (Debye ring). A diffraction pattern showing an X-ray diffraction intensity distribution as shown in FIG. 6 is obtained from this diffraction pattern (Debye ring). The diffraction pattern indicating the X-ray diffraction intensity distribution indicates the X-ray diffraction intensity distribution in the radial direction from the center of the Debye ring, and the horizontal axis indicates the X-ray diffraction angle 2θ, and a specific position on the horizontal axis. The diffraction peak identified in is considered to represent the distance between polymer chains. By fixing the angle at which such a diffraction peak was obtained (peak scattering angle) and measuring the X-ray diffraction intensity distribution from 0 ° to 360 ° in the azimuth angle direction (circumferential direction of the Debye ring), An X-ray diffraction intensity distribution in the azimuth direction as shown in FIG. The steeper peak in the X-ray diffraction intensity distribution in such an azimuth direction indicates that the polymer chain is highly oriented in a certain direction. Accordingly, in such an X-ray diffraction intensity distribution in the azimuth angle direction, a width at half the peak height (half-value width ΔB) is obtained, and this half-value width ΔB is substituted into the following formula (i) to obtain a polymer chain. The degree of orientation can be calculated.

Orientation degree A = (180−ΔB) / 180 (i)
The higher the degree of orientation A, the more efficiently the heat is conducted. The orientation degree A in the polymer film 11 is preferably in the range of 0.6 or more and less than 1.0, more preferably in the range of 0.65 or more and less than 1.0, and still more preferably in the range of 0.7 or more and less than 1.0. It is. If the degree of orientation A is less than 0.6, the thermal conductivity due to the orientation of the polymer chain may not be sufficiently exhibited. When obtaining the polymer film 11 with an increased degree of orientation A so that the degree of orientation A is, for example, 0.6 or more, in the production process of the polymer film 11, the polymer is oriented in the direction of orientation. On the other hand, the shrinkage force in the direction perpendicular to the direction is further increased. In the manufacturing method including a curing step using a pressure body as in the present embodiment, the shrinkage of the polymer solidified body 13 can be suitably suppressed even when the degree of orientation A is increased. The smoothness of the front and back surfaces of the polymer film 11 to be obtained can be improved.

In this polymer film 11, the surface roughness of the front and back surfaces is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 7. In the ten-point average roughness (Rz) defined in JIS B 0601-1994. It is 0 μm or less, most preferably 6.5 μm or less. When the ten-point average roughness (Rz) exceeds 15 μm, there is a possibility that sufficient adhesion with the heat generator or the heat radiator cannot be obtained. The lower limit of the ten-point average roughness (Rz) is not particularly limited, but is 0.1 μm or more considering the properties of the polymer film 11. The 10-point average roughness (Rz) defined in JIS B 0601-1994 is the 10-point average roughness (Rz _JIS94 ) calculated using the contour curve applied with the phase compensation wide-area filter.

  This polymer film 11 is cut into a predetermined size and used as necessary. The polymer film 11 is fully applied to applications requiring thermal conductivity, so that the function of the polymer film 11 is sufficiently exhibited. In the electronic component shown in FIG. 8, the polymer film 11 is interposed between a ball grid array type semiconductor package 32 mounted on a printed board 31 and a radiator 33.

  In the electronic component shown in FIG. 9, the polymer film 11 is interposed between a semiconductor chip 41 and a die pad 42 that functions as a heat dissipation portion. In this electronic component, the electrode part of the semiconductor chip 41 and the lead part of the lead frame 44 are electrically connected by a bonding wire 43. Then, the semiconductor chip 41 and the bonding wire 43 are sealed with a sealing material 45 formed from an epoxy sealant by molding with an epoxy sealant by a transfer molding method.

  In the electronic component shown in FIG. 10, the polymer film 11 is interposed between the chip size semiconductor package 51 and the printed board 31. In the electronic component shown in FIG. 11, the polymer film 11 is interposed between a pin grid array type semiconductor package 34 mounted on a printed circuit board 31 and a heat sink 35 as a radiator.

  The polymer film 11 is suppressed in variation in thickness by a curing process accompanied by pressurization. The thickness of the polymer film 11 is not particularly limited, but is about 10 to 300 μm. Since the polymer film 11 has improved smoothness on the front and back surfaces, for example, when the polymer film 11 is interposed between a heat generator such as a semiconductor chip or each semiconductor package and a heat radiator such as a heat sink, the polymer film 11 Adhesiveness between the film 11 and the heat generator or heat radiator is improved, and heat from the heat generator can be efficiently transmitted to the heat radiator. In particular, heat generated in an electronic component including an IC or the like may interfere with the operation of the semiconductor element or cause a crack in the package. Therefore, such a heat dissipation measure for the electronic component is important. By using the polymer film 11 at a site that is in close contact with such an electronic component, heat generated from the electronic component can be efficiently radiated.

The effects exhibited by this embodiment will be described below.
(1) The curing step for curing the polymer coagulated body is performed in a state where the polymer coagulated body is pressurized by a pressure body arranged in close contact with the polymer coagulated body. And this pressurization body has air permeability. For this reason, in the polymer solidified body in the curing step, the shape is held by the pressure body, and drying through the pressure body is performed.

  By the way, the polymer coagulation body in which the front and back surfaces are sandwiched between the metal plates when the pressure plate of the present embodiment is used, for example, using a metal plate that does not have air permeability, The drying through the peripheral edge portion is performed without drying through. In this case, the peripheral edge portion of the polymer solidified body is cured prior to the central portion of the polymer solidified body. That is, since the peripheral portion of the polymer solidified body is cured with shrinkage, the thickness of the polymer solidified body varies as a result of the shrinkage force. As a result, the smoothness of the front and back surfaces of the resulting polymer film decreases. . Such a shrinkage force at the peripheral edge of the polymer coagulation becomes significant when the polymer chains of the polymer coagulation are oriented in a magnetic field or an electric field.

  According to the curing step of the present embodiment, even when the polymer chain is highly oriented by the orientation step and is highly susceptible to shrinkage by drying, the polymer coagulation shrinks in the curing step. Can be suitably suppressed. Therefore, the smoothness on the front and back surfaces of the polymer film 11 can be improved by applying such a curing step. As a result, the thermal conductivity of the polymer film 11 can be sufficiently exhibited by improving the adhesion of the polymer film 11 to a heating element such as an electronic component.

  Furthermore, in this curing step, the shrinkage of the polymer solidified body is suitably suppressed, so that flexibility (flexibility) and bending strength are enhanced. For this reason, since it is easy to arrange the polymer film 11 following the shape even in a bent portion of an applied product such as an electronic component, the thermal conductivity of the polymer film 11 can be easily exhibited. In addition, the durability of the polymer film 11 can be sufficiently exhibited.

  Moreover, in the manufacturing method with the conventional orientation process, it was extremely difficult to obtain a polymer film with smooth front and back surfaces and small thickness variations. That is, in the conventional polymer film, the smoothness and thickness uniformity are not sufficiently obtained, and therefore, the electrochemical migration is accelerated by the great heat generated from the electronic parts such as semiconductor elements, and the wiring And corrosion of the pad portion may be accelerated. Also, in such conventional polymer films, the heat dissipation required for electronic components is not sufficiently exhibited, so that the material constituting the electronic components cracks due to thermal stress, or the interface between the joints of different materials It sometimes peeled off. As a result, it has been difficult to extend the life of the electronic component. In the polymer film 11 of the present embodiment, the smoothness of the front and back surfaces is improved and the variation in thickness is suppressed by a curing step involving pressurization. For this reason, as a result of suppressing migration, corrosion of wiring and pad portions, defects of materials constituting the electronic component, and the like as in the past, the lifetime of the electronic component can be extended.

  Furthermore, in this polymer film 11, since the generation of wrinkles is suppressed by the above-described curing step, the yield of the polymer film 11 can be improved according to this manufacturing method.

  (2) By setting the pressure of the pressurization in the curing step to 0.49 MPa to 9.8 MPa, the orientation of the polymer chain can be suitably maintained, and the shrinkage of the polymer solidified body in the curing step is preferable. Can be suppressed. Therefore, in the obtained polymer film 11, the smoothness and heat conductivity of the front and back surfaces are imparted with a good balance, so that the heat conductivity of the polymer film 11 can be further exhibited. Furthermore, the flexibility (flexibility) and bending strength of the polymer film 11 can be further increased. In addition, since the generation of cracks in the polymer film 11 after curing can be suppressed, the yield of the polymer film 11 can be further improved.

  (3) It is preferable to use the porous plate 24 as a pressurizing body. Since the porous plate 24 can easily form the smoothness and breathability of the surface, the smoothness on the front and back surfaces of the resulting polymer film 11 can be further improved. Furthermore, since the porous plate 24 can easily obtain the strength against the pressure of pressurization, sufficient durability can be exhibited even in repeated use.

  (4) In the curing step, it is preferable that the polymer solidified body is heated. As a result of the efficient drying of the polymer solidified body by this heating, the production efficiency of the polymer film 11 can be improved.

  (5) By performing the curing step so as to satisfy the relationship of shrinkage remaining rate R (%) ≧ 50 (%), the smoothness on the front and back surfaces of the polymer film 11 can be controlled with high accuracy. Further, by satisfying the relationship of shrinkage remaining rate R (%) ≧ 50 (%), the polymer coagulated polymer becomes excessively dense in the curing process, or the polymer coagulated material is excessively thick. Therefore, the flexibility (flexibility) and folding strength of the resulting polymer film 11 can be further increased.

  (6) In the curing step, the polymer solidified body is sandwiched between the pressure bodies, so that the polymer solidified body is dried from the front and back surfaces through the pressure body. For this reason, since shrinkage | contraction of a polymer solidified body is further suppressed, the smoothness in the front and back of the polymer film 11 can be improved more. Furthermore, since the physical property difference such as smoothness on the front and back surfaces can be extremely reduced, the polymer film 11 exhibits the same degree of thermal conductivity even when the front and back surfaces are in close contact with the heating element. Can be made.

  (7) The polymer of the polymer film 11 is preferably a lyotropic liquid crystal polymer, and among the lyotropic liquid crystal polymers, at least one selected from polyparaphenylene terephthalamide, polybenzimide, polyparaphenylene, and polybenzazole is used. More preferred. In this case, the polymer film 11 having high strength and high elastic modulus and excellent in heat resistance and flame retardancy can be provided.

In addition, the said embodiment can also be changed and comprised as follows.
-You may perform a hardening process, without heating a polymer solidified body. For example, by performing the curing step under reduced pressure without heating the polymer solidified body, the volatilization of the solvent from the polymer solidified body is promoted, and the drying efficiency of the polymer solidified body can be increased. The production efficiency of the polymer film 11 can be improved. In addition, the production efficiency of the polymer film 11 can be further improved by performing the curing step under reduced pressure while heating the polymer solidified body.

  The polymer film 11 is a polymer film 11 having a single layer structure, but may be configured as a polymer film having a laminated structure. In order to produce a polymer film having a laminated structure, for example, a coextrusion method in which a polymer solution is laminated in a die die, a method in which a second layer is laminated on a first layer formed in advance, etc. The method can be applied. In addition, the polymer film having a laminated structure is formed by applying another polymer film formed from a polymer such as a thermoplastic resin as the first layer and configuring the second layer as the polymer film of the present embodiment. Alternatively, another polymer film in which the first layer is configured as the polymer film of the present embodiment and the second layer is formed from a polymer such as a thermoplastic resin may be applied. Further, when a polymer film having a laminated structure of three or more layers is used, if the polymer film of the present embodiment is configured as the outermost layer, a heating element utilizing the smoothness on the surface of the polymer film of the present embodiment. Adhesion can be improved.

  In the curing step, the polymer solidified body 13 is sandwiched between a pair of upper and lower porous plates 24 as shown in FIG. 4, but at least one of the porous plates 24 is not air permeable. The pressure body may be changed. Even in this case, the polymer film 11 can be produced while suppressing the shrinkage of the polymer solidified body 13 due to the air permeability of the porous plate 24. Therefore, the smoothness of the front and back surfaces of the polymer film 11 can be improved. Can be improved.

  In the alignment step, the polymer chain of the polymer substrate 12 formed into a film is aligned, but the shape of the polymer substrate 12 in the alignment step, that is, the shape of the polymer solution in the alignment step is not particularly limited. . For example, the polymer solution may be formed into a plate shape, a block shape, or the like. Similarly, the polymer molded body is not limited to the polymer film 11, and the shape of the polymer molded body may be changed to, for example, a plate shape or a block shape.

Next, the embodiment will be described more specifically with reference to examples and comparative examples.
Example 1
As a polymer, a polybenzoxazole in which Ar ₁ and Ar ₂ in the formula (1) are both benzene rings and X is an oxygen atom was synthesized. First, in a reaction vessel equipped with a stirrer, a nitrogen introduction tube, and a dryer, 300 g of polyphosphoric acid (H ₃ PO ₄ equivalent: 115%), 5 g (2,3.4 mmol) of 4,6-diaminoresorcinol dihydrochloride, terephthalic acid 4.76 g (23.4 mmol) of dichloride was charged and stirred at 70 ° C. for 16 hours. Further, while stirring the solution, the temperature was raised stepwise in the order of 90 ° C. for 5 hours, 130 ° C. for 3 hours, 150 ° C. for 16 hours, 170 ° C. for 3 hours, 185 ° C. for 3 hours, and 200 ° C. for 48 hours. The solution was reacted by warming and maintaining the temperature at each stage for a certain time to obtain a crude polybenzoxazole solution. Next, the crude polybenzoxazole solution was reprecipitated with methanol, acetone and water to obtain polybenzoxazole having an intrinsic viscosity of about 10 dl / g. Polyphosphoric acid was added to the obtained polybenzoxazole to prepare a polybenzoxazole solution having a final concentration of 10% by mass. The polybenzoxazole solution as the polymer solution thus obtained was confirmed to exhibit optical anisotropy (liquid crystallinity) by observation using a polarizing microscope.

  After the obtained polybenzoxazole solution is applied to one molding resin film 21 shown in FIG. 1, the other molding resin film 21 is used to sandwich the polybenzoxazole solution, thereby forming a film-like film. The polymer substrate 12 was molded. In addition, as the resin film 21 for shaping | molding, the PET film by which the fluorine coat process was given to the surface was used. Next, as shown in FIG. 2, a pair of magnets 22 are arranged above and below the polymer substrate 12 so that the magnetic lines of force 23 are parallel to the thickness direction of the polymer substrate 12. These magnets 22 were heated at 120 ° C. for 20 minutes while applying a 10 T magnetic field to the polymer substrate 12. Furthermore, the alignment step was completed by allowing the polymer substrate 12 to stand still and naturally cooling to room temperature.

  Next, after removing one of the molding resin films 21 from the polymer substrate 12, it was immersed in a mixed solution of methanol and water as a coagulating liquid. In this mixed solution, the other molding resin film 21 was removed from the polymer substrate 12, and the polymer substrate 12 was solidified to obtain a film-shaped polymer coagulated body. The polymer coagulation was immersed in the mixed solution for 1 hour, then immersed in water for 1 hour and further in acetone for 10 minutes to complete the coagulation step.

  Next, as shown in FIG. 4, the polymer solidified body 13 is sandwiched between a pair of porous plates 24, and dried at a pressure of 0.98 MPa at 120 ° C. for 1 hour and at the same pressure at 150 ° C. for 1 hour. Thus, the curing step was completed, and the polymer film 11 was obtained. The porous plate 24 is made of aluminum and has an average pore diameter of 15 to 18 μm and a porosity of 15 to 20%.

(Examples 2 to 6)
Except having changed into the pressure of Table 1, each polymer film 11 was obtained by the method similar to Example 1. FIG.

(Example 7)
After molding the polymer substrate 12 from the polybenzoxazole solution, a pair of magnets 22 are arranged on the left and right sides of the polymer substrate 12 so that the magnetic lines of force 23 are parallel to the front and back surfaces of the polymer substrate 12 as shown in FIG. A polymer film 11 was obtained in the same manner as in Example 1 except that.

(Comparative Example 1)
In the same manner as in Example 1, a film-like polymer substrate 12 was molded. Next, as shown in FIG. 2, a pair of magnets 22 are arranged above and below the polymer substrate 12 so that the magnetic lines of force 23 are parallel to the thickness direction of the polymer substrate 12. In this way, the polymer substrate 12 was heated at 120 ° C. for 20 minutes while applying a 10 T magnetic field. Furthermore, the alignment step was completed by allowing the polymer substrate 12 to stand still and naturally cooling to room temperature.

  Next, after removing one of the molding resin films 21 from the polymer substrate 12, it was immersed in a mixed solution of methanol and water as a coagulating liquid. In this mixed solution, the other molding resin film 21 was removed from the polymer substrate 12, and the polymer substrate 12 was solidified to obtain a film-shaped polymer coagulated body. The polymer coagulation was immersed in the mixed solution for 1 hour, then immersed in water for 1 hour and further in acetone for 10 minutes to complete the coagulation step.

  Next, after taking out the polymer solidified body, the polymer solidified body is dried at 120 ° C. for 1 hour and at 150 ° C. for 1 hour without being restrained or pressurized, thereby completing the curing step. A film was obtained.

(Comparative Example 2)
In the curing step, the polymer solidified body was sandwiched between a pair of aluminum plates and dried in the same manner as in Comparative Example 1 except that it was dried at 0.12 MPa for 1 hour at 120 ° C. and for 1 hour at 150 ° C. under the same pressure. Thus, a polymer film was obtained.

(Comparative Examples 3 and 4)
Except having changed into the pressure of Table 2, each polymer film was obtained by the method similar to the comparative example 2.

(Comparative Example 5)
In the alignment step, the same method as in Comparative Example 1 except that a pair of magnets 22 are arranged on the left and right sides of the polymer substrate 12 so that the magnetic lines of force 23 are parallel to the front and back surfaces of the polymer substrate 12 as shown in FIG. The polymer chain of the polymer substrate 12 was aligned. Next, the obtained polymer substrate 12 was subjected to a coagulation step by the same method as in Comparative Example 1. Subsequently, the obtained polymer solidified body was subjected to a curing step in the same manner as in Comparative Example 2.

(Comparative Example 6)
A polyimide film (PI) having a thickness of 125 μm (trade name “Kapton” manufactured by DuPont) was used as the polymer film of Comparative Example 7.

表１及び表２に示される配向度Ａ、収縮残存率Ｒ、熱拡散率α、及び熱伝導率λの算出方法、並びに十点平均粗さＲｚの測定方法について以下に記載する。

A method for calculating the degree of orientation A, shrinkage residual rate R, thermal diffusivity α, and thermal conductivity λ shown in Tables 1 and 2 and a method for measuring the ten-point average roughness Rz are described below.

<Orientation degree A>
The degree of orientation A of the polymer film, using an X-ray diffractometer (“RINT-RAPID” manufactured by Rigaku Corporation), half of the peak in the azimuth X-ray diffraction intensity distribution of each polymer film obtained It was calculated from the value width ΔB by the above-described equation (i). As an example, for the polymer film 11 of Example 1, FIG. 6 shows a diffraction pattern in the equator direction by X-ray diffraction measurement, and FIG. 7 shows an X-ray diffraction intensity distribution in the azimuth direction at a diffraction peak angle 2θ = about 26 °. Indicates.

<Shrinkage residual rate R>
The surface area of the polymer coagulated body in a state where it was not pressed or restrained by the porous plate 24 or the aluminum plate was measured, and this surface area was defined as an area A1 in the shrinkage residual rate R (%). Further, the polymer film having undergone the curing step was allowed to stand for 24 hours in an environment of a temperature of 25 ° C. and a relative humidity of 50%, and then the surface area of the polymer film was measured. ) In area A2. By substituting these areas A1 and A2 into the following equation, the residual shrinkage ratio R (%) was calculated.

Shrinkage residual rate R (%) = A2 / A1 × 100
<Thermal diffusivity α>
The thermal diffusivity α _Z in the thickness direction of the polymer film is measured directly by sputtering on the surface of each polymer film using a thermal diffusivity measuring device (trade name “Eye Phase α”, manufactured by Eye Phase Co., Ltd.). Then, a lead wire was attached with a silver paste, a sensor was in contact with the lower surface of each polymer film, and a heater was in contact with the upper surface, and measurement was performed at room temperature. In addition, the thermal diffusivity α _{X in} the direction along the front and back surfaces is measured by using a two-dimensional thermal analyzer (trade name “Eye Phase IR”, manufactured by Eye Phase Co., Ltd.) using an infrared camera. An electrode having an L-shaped length of 4 mm and a width of 1 mm was directly formed by sputtering, and measurement was performed from observation of heat flow at room temperature in the X-axis direction and the Y-axis direction shown in FIG.

<Thermal conductivity λ>
The thermal conductivity λ was determined by the following formula (ii) from the thermal diffusivity α of the polymer film.
Thermal conductivity λ = α · ρ · C _P (ii)
(However, alpha is the thermal diffusivity, [rho is the density, C _P represents the specific heat.)
<10-point average roughness (Rz)>
About each polymer film, it measured using the "surface roughness shape measuring machine" (The Tokyo Seimitsu make, brand name "Surfcom 550A") based on JISB0601-1994.

(Polymer film evaluation results)
As shown in Table 1, in the polymer films 11 of Examples 1 to 7, the values of thermal diffusivity and thermal conductivity are higher than those of the conventional polymer film shown in Comparative Example 7, It can be seen that the polymer film 11 of each example exhibits better thermal conductivity than the polymer film of Comparative Example 7.

  Furthermore, the measurement result of the ten-point average roughness (Rz) of the polymer film 11 of each Example shows a smaller value than the measurement results of Comparative Examples 1-5. The ten-point average roughness (Rz) measurement results show that the smoothness of the front and back surfaces is improved in the polymer film 11 of each example. It shows that the heat conduction performance can be sufficiently exhibited by improving the adhesion of the polymer film 11 to the heating element and the heat radiator when used.

<Evaluation of wrinkles>
The state of the front and back surfaces of each polymer film was observed and evaluated for the presence or absence of wrinkles. The results are shown in Table 3.

<Evaluation of flex life>
The bending life of each polymer film is indicated by the number of bendings until each polymer film breaks under the conditions of a bending radius of about 10 mm, a bending speed of 100 times / minute, a stroke of 20 mm, and room temperature. Table 3 shows the results when the number of flexing times is 50,000 times or more and ○ (achieved), and those with less than 50,000 times are x (not achieved).

<Evaluation of cracking>
The surface state of each polymer film was observed and evaluated for the presence or absence of cracks. The results are shown in Table 3.

表３に示されるように各実施例の高分子フィルム１１には、しわの発生がないことから、各実施例の製造方法によれば、歩留まりよく高分子フィルム１１を製造することができる。

As shown in Table 3, the polymer film 11 of each example does not have wrinkles. Therefore, according to the manufacturing method of each example, the polymer film 11 can be manufactured with high yield.

  Furthermore, in Examples 1-5 and Example 7, since the pressure of the pressurization in the curing process was set in the range of 0.49 MPa to 9.8 MPa, the obtained polymer film 11 had excellent flexibility. have. For this reason, in Examples 1 to 5 and Example 7, as shown in Table 3, the bending life is excellent. As described above, since the polymer films 11 of Examples 1 to 5 and Example 7 are excellent in flexibility, they can be easily placed in the bent portions of various electronic devices, and have a sufficient bending life. Therefore, sufficient durability can be exhibited even when it is disposed at such a bent portion. In addition, since the polymer films 11 of Examples 1 to 5 and Example 7 do not generate cracks, the yield can be further improved when the polymer film 11 is manufactured.

(Example 8)
In the same manner as in Example 1, a polymer coagulation product was obtained by performing an alignment step and a coagulation step using a polybenzoxazole solution as a raw material. About the obtained polymer solidified body, the polymer film 11 was obtained by performing the hardening process similarly to Example 1 except having changed the conditions in a hardening process into 120 degreeC and 2 hours. The thickness of the obtained polymer film 11 was 150 μm.

  This polymer film 11 was applied to the electronic component shown in FIG. That is, the polymer film 11 was disposed on the ball grid array type semiconductor package 32 mounted on the printed circuit board 31, and the radiator 33 was disposed on the polymer film 11, thereby producing an electronic component.

Example 9
The polymer film 11 obtained in Example 1 was applied to the electronic component shown in FIG. That is, the polymer film 11 is sandwiched between the die pad 42 and the semiconductor chip 41, and the electrode part of the semiconductor chip 41 and the lead part of the lead frame 44 are electrically connected by the bonding wire 43, and then the epoxy-based sealing is performed. An electronic component was molded by a transfer molding method using an agent.

(Example 10)
The polymer film 11 obtained in Example 3 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 8 except that the polymer film 11 was changed.

(Example 11)
The polymer film 11 obtained in Example 3 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 9 except that the polymer film 11 was changed.

(Example 12)
The polymer film 11 obtained in Example 7 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 8 except that the polymer film 11 was changed.

(Example 13)
The polymer film 11 obtained in Example 7 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 9 except that the polymer film 11 was changed.

(Comparative Example 7)
The polymer film obtained in Comparative Example 3 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 8 except that the polymer film was changed.

(Comparative Example 8)
The polymer film obtained in Comparative Example 3 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 9 except that the polymer film was changed.

(Comparative Example 9)
The polymer film of Comparative Example 6 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 8 except that the polymer film was changed.

(Comparative Example 10)
The polymer film of Comparative Example 6 was applied to the electronic component shown in FIG. That is, an electronic component was produced in the same manner as in Example 9 except that the polymer film was changed.

<Measurement of thermal resistance value>
After energizing the electronic parts of Examples 8 to 13 and Comparative Examples 7 to 10 for 10 minutes, the surface temperature of the electronic parts was measured. In the electronic component shown in FIG. 8, the surface temperature θ _j1 of the printed circuit board 31 and the surface temperature θ _j0 of the radiator 33 were measured. In the electronic component shown in FIG. 9, the surface temperature θ _j1 on the semiconductor chip 41 side and the surface temperature θ _j0 on the die pad 42 side were measured. The thermal resistance value (° C./W) was calculated by substituting the surface temperatures θ _j1 and θ _j0 into the following equation.

Thermal resistance value (° _{C./W)=(θ j1} −θ _j0 ) / Heat generation amount of electronic component (W)
The measurement results of the thermal resistance value (° C./W) are shown in Table 4.

表４の結果から明らかなように、実施例８〜１３の熱抵抗値は、比較例７〜１０の熱抵抗値よりも小さい値を示しており、各実施例の電子部品では放熱特性が改善されている。

As is clear from the results in Table 4, the thermal resistance values of Examples 8 to 13 are smaller than the thermal resistance values of Comparative Examples 7 to 10, and the heat dissipation characteristics are improved in the electronic components of each Example. Has been.

Schematic which shows the shaping | molding method of the polymer base | substrate in this embodiment. Schematic which shows the orientation process which orientates a polymer chain in the thickness direction of a polymer base | substrate. Schematic which shows the orientation process which orientates a polymer chain in the direction along the front and back of a polymer base | substrate. Schematic which shows a hardening process. The perspective view which shows a polymer film. The graph which shows the example of the X-ray-diffraction pattern of radial direction from the center of the Debye ring of a polymer film. The graph which shows the example of the X-ray diffraction intensity distribution of the azimuth angle direction of a polymer film. Sectional drawing which shows an example of the electronic component to which a polymer film is applied. Sectional drawing which shows an example of the electronic component to which a polymer film is applied. Sectional drawing which shows an example of the electronic component to which a polymer film is applied. Sectional drawing which shows an example of the electronic component to which a polymer film is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Polymer film as a polymer molded body, 13 ... Polymer coagulation body, 24 ... Porous board as a pressurization body.

Claims (8)

An alignment step of orienting polymer chains in the polymer solution in a certain direction by applying a magnetic field or an electric field to the polymer solution expressing optical anisotropy;
A coagulation step for obtaining a polymer coagulum by coagulating the polymer oriented by the orientation step;
A curing step for obtaining a polymer molded body by curing the polymer solidified body,
A method for producing a polymer molded body for producing the polymer molded body from the polymer solution,
In the curing step,
Drying of the polymer coagulation body through the pressure body is performed in a state where the pressure body that has air permeability and pressurizes the polymer coagulation body is disposed in close contact with the polymer coagulation body. A method for producing a polymer molded body characterized by the above. 2. The method for producing a polymer molded body according to claim 1, wherein the pressure applied in the curing step is 0.49 MPa to 9.8 MPa. The method for producing a polymer molded body according to claim 1 or 2, wherein the pressure body is a porous plate. The method for producing a polymer molded body according to any one of claims 1 to 3, wherein the polymer solidified body is heated in the curing step. The polymer solution is formed into a film,
The curing step is
The area of the surface orthogonal to the thickness direction of the polymer solidified body subjected to the curing step is A1, and the area of the surface orthogonal to the thickness direction of the polymer molded body obtained by the curing step is A2. The shrinkage remaining rate R (%) = A2 / A1 × 100 expressed as follows is satisfied so as to satisfy the relationship of shrinkage remaining rate R (%) ≧ 50 (%). The manufacturing method of the polymer molded object of description. The method for producing a polymer molded body according to any one of claims 1 to 5, wherein in the curing step, the polymer solidified body is sandwiched between the pressure bodies. A polymer molded body obtained by the method for producing a polymer molded body according to any one of claims 1 to 6,
A polymer molded product, wherein the polymer in the polymer solution is a lyotropic liquid crystal polymer. The polymer molded product according to claim 7, wherein the lyotropic liquid crystal polymer is at least one selected from polyparaphenylene terephthalamide, polybenzimide, polyparaphenylene, and polybenzazole.

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