JP2010106059A - Polybenzazole composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybenzazole composite having an excellent anisotropic function and improved thermal property in a thickness direction. <P>SOLUTION: The polybenzazole composite 1 includes a film-like substrate 6 comprising a polybenzazole having at least one of four predetermined polybenzazole repeating units. In the film-like substrate 6, molecular chains of the polybenzazole are oriented in a thickness direction, and a plurality of recesses 6b are formed on the surface 6a of the film-like substrate 6. An elastic member 7 is provided to intrude into the recesses 6b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polybenzazole complex having an excellent anisotropic function and improved thermal properties by highly oriented molecular chains.

In recent years, films formed from polybenzazole have high strength and high elastic modulus, and are excellent in heat resistance and flame retardancy, such as magnetic tape, insulating films for electrical and electronic parts, liquid crystal alignment films, etc. Much research is being done for new applications. For example, Patent Document 1 discloses a film-shaped polybenzazole molded body that is biaxially stretched and oriented in the stretching direction. Patent Document 2 discloses a film-shaped polybenzazole molded body having a specific surface roughness excellent in smoothness. Patent Document 3 discloses a film-like polybenzazole molded body having specific elongation and Young's modulus suitable for a magnetic recording medium. Patent Document 4 discloses a method for producing a polybenzazole molded body in which molecular chains are aligned in the thickness direction. The method includes a step of preparing a solvent solution of polybenzazole, a step of forming an intermediate from the solvent solution, and applying a magnetic field to the obtained intermediate to move the polybenzazole molecular chain in a certain direction. And the step of solidifying the intermediate while maintaining the orientation state of the polybenzazole molecular chain.
JP-T 6-503521 Japanese Patent Laid-Open No. 11-171993 JP 2000-273214 A JP 2006-182898 A

  By using a method such as stretching disclosed in Patent Documents 1 to 3, a polybenzazole film having good smoothness can be obtained. However, since the molecular chain of polybenzazole is a rigid rod, the molecular chain of polybenzazole can only be obtained along the plane of the film. Patent Document 4 discloses a method for producing a polybenzazole film in which molecular chains are oriented in the thickness direction and an anisotropic function is expressed in the thickness direction. However, in this manufacturing method, the molecular chains are oriented along the thickness direction, so that irregularities due to wrinkles or wrinkles are easily generated.

Due to the unevenness caused by such warps and wrinkles, there is a problem that the performance expected from the polybenzazole film, in particular, thermal properties cannot be exhibited.
The present invention has been made paying attention to the problems existing in the prior art as described above. The purpose is to provide a polybenzazole complex that exhibits an excellent anisotropic function and improved thermal properties in the thickness direction due to the highly oriented molecular chains along the thickness direction. It is to provide.

In order to solve the above-mentioned problems in the prior art, the invention described in claim 1 is characterized by the following general formulas (1) to (4) (wherein X represents a sulfur atom, an oxygen atom or an imino group, Ar ₁ And Ar ₂ represents an aromatic hydrocarbon group, and n is an integer of 10 to 500), and the molecular chain of the polybenzazole has a thickness. Provided is a polybenzazole composite comprising a film-like substrate oriented in the direction and having a plurality of recesses formed on the surface, and an elastic member that enters the recesses of the film-like substrate.

請求項２に記載の発明は、請求項１記載のポリベンズアゾール複合体について、前記弾性部材が粘着剤からなることを要旨とする。

The invention according to claim 2 is the gist of the polybenzazole complex according to claim 1, wherein the elastic member is made of an adhesive.

  The invention according to claim 3 is the gist of the polybenzazole complex according to claim 1, wherein the elastic member is a rubber-like elastic body having a type E hardness of 30 or less as defined in JIS K 6253. To do.

The gist of the invention described in claim 4 is that the polybenzazole complex according to any one of claims 1 to 3 includes a heat conductive filler in the elastic member.
The invention according to claim 5 is the gist of the polybenzazole complex according to any one of claims 1 to 4, wherein the elastic member has a thickness of 40 μm or less.

  According to the polybenzazole complex of the present invention, the thermal resistance value in the thickness direction can be reduced while having the properties of polybenzazole.

Hereinafter, embodiments of the polybenzazole complex of the present invention will be described.
FIG. 1 shows an embodiment in which the polybenzazole composite of the present invention is embodied as a polybenzazole composite film 1. The polybenzazole composite film 1 includes a film base 6 made of polybenzazole and an elastic member 7. The film-like substrate 6 has a polybenzazole molecular chain oriented in the thickness direction and a plurality of concave portions 6b and a plurality of convex portions 6c formed on the surface 6a. The elastic member 7 is provided on the film base 6 so as to enter the recess 6b of the surface 6a of the film base 6. Thus, the polybenzazole composite film 1 is a composite of the polybenzazole and the elastic member 7.

  In the present invention, polybenzazole refers to a polymer containing at least one selected from polybenzoxazole (PBO), polybenzothiazole (PBT), and polybenzimidazole (PBI). Examples of such polybenzazoles include homopolymers consisting of any one of PBO, PBT, and PBI, mixtures of two or more selected from PBO, PBT, and PBI, block copolymers, or random copolymers, and PBO, PBT, or PBI. Among them, a copolymer containing at least one of them can be mentioned.

  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 complex of the present invention includes polybenzazole having at least one of the repeating units represented by the general formulas (1) to (4).
In the general formulas (1) to (4), X represents a sulfur atom, an oxygen atom or an imino group, Ar ₁ and Ar ₂ each represent an aromatic hydrocarbon group, and n is an integer of 10 to 500.

Specific examples of Ar ₁ include those 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）で示すものが挙げられる。

Specific examples of Ar ₂ include those 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なわれてもよいし、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なわれてもよい。

Z in the general formula (I) ~ (VIII), respectively oxygen atom, a sulfur _{atom, SO 2, CO, CH 2} , C (CH 3) 2, CF 2 or C _{(CF 3) 2} in any Or a direct bond between carbons in adjacent benzene rings. In the benzene rings in the 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 part before the polycondensation reaction, or may be performed on the corresponding part of the polybenzazole after the polycondensation reaction.

The polybenzazole complex of the present invention is most preferably 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 Ar ₂ are formed from polybenzazoles in which in formulas (I) to (VIII), Z represents an oxygen atom or a direct bond. By having such a structure, the polybenzazole molecular chain becomes more linear and is oriented in a certain direction (thickness direction), so that a higher anisotropic function is expressed.

  In addition to the repeating units represented by the above general formulas (1) to (4), the polybenzazole of the present invention is unreacted as represented by the following formulas (IX) and (X) generated in the production process. It may contain a repeating unit having a ring-opening moiety.

上記一般式（１）〜（４）で示される繰り返し単位を有するポリベンズアゾールは、溶媒に溶解すると所定の濃度範囲において光学異方性を示し、特に限られた濃度範囲においてはリオトロピック液晶性を示す。このようにポリベンズアゾールが光学異方性を示す状態、すなわちポリベンズアゾール分子鎖が一定の規則性を有している状態において、磁場または電場の印加などの手段により、ポリベンズアゾールの分子鎖をフィルム状基体６の厚さ方向にさらに配向させることによって、ポリベンズアゾールの分子鎖がより高度に配向した複合体を得ることができる。このように、本発明のポリベンズアゾール複合体は、ポリベンズアゾールの分子鎖が厚さ方向に配向されることにより、異方性機能を発現するように構成されている。

The polybenzazole having the repeating units represented by the general formulas (1) to (4) exhibits optical anisotropy in a predetermined concentration range when dissolved in a solvent, and exhibits lyotropic liquid crystallinity particularly in a limited concentration range. Show. Thus, in a state where polybenzazole exhibits optical anisotropy, that is, in a state where the polybenzazole molecular chain has a certain regularity, the molecular chain of polybenzazole is applied by means such as application of a magnetic field or an electric field. Is further oriented in the thickness direction of the film-like substrate 6 to obtain a composite in which the molecular chains of polybenzazole are more highly oriented. Thus, the polybenzazole complex of the present invention is configured to exhibit an anisotropic function by orienting the molecular chain of polybenzazole in the thickness direction.

  The orientation of the molecular chain containing polybenzazole is such that when the polybenzazole complex has a predetermined light transmittance, optical anisotropy (phase difference, birefringence using two polarizers or a polarizing microscope) is used. ) Measurement or a polarized infrared absorption spectrum analysis method. Further, it can be confirmed by a polarization 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.

  In the polybenzazole complex of the present invention, the characteristic that anisotropy is manifested is at least one selected from optical properties, magnetic properties, mechanical properties, thermal properties, physical properties, and electrical properties. Useful. More specifically, characteristics such as thermal conductivity, linear expansion coefficient, dielectric constant, light permeability, gas permeability, liquid permeability, electrical conductivity, and ionic conductivity can be mentioned. For example, a polybenzazole molecular chain oriented in a certain direction in a polybenzazole complex or a mixed molecular chain containing polybenzazole acts as a π-electron conjugated molecule, and the π-electron conjugated system extends in a certain orientation direction. Thus, the composite can exhibit an anisotropic function in magnetic properties. In general, heat conduction in an insulator such as a polymer material is caused by phonon scattering, and this phonon is considered to be easily scattered along the longitudinal direction of the molecular chain. Therefore, when the polybenzazole molecular chain or the mixed molecular chain containing polybenzazole is oriented in a certain direction in the composite, the thermal conductivity λ in that direction is improved, and excellent thermal conductivity is exhibited. It becomes possible.

  In the above embodiment, the polybenzazole molecular chain is oriented in the thickness direction in the composite, and the degree of orientation A of the polybenzazole molecular chain determined by the following formula (i) is 0.6 or more and 1. It is in the range of less than 0.

Orientation degree A = (180−ΔB) / 180 (i)
The degree of orientation A of the polybenzazole molecular chain is determined by performing wide-angle X-ray diffraction measurement (transmission) of the polybenzazole complex.

  The orientation degree A in the polybenzazole complex of the present invention is preferably in the range of 0.6 or more and less than 1.0, more preferably 0.65 or more and less than 1.0, and most preferably 0.7 or more and less than 1.0. It is in. When the degree of orientation A is less than 0.6, the polybenzazole molecular chain is not sufficiently oriented in the complex. Therefore, the thermal conductivity λ in the thickness direction of the polybenzazole composite is low, and sufficient thermal conductivity cannot be obtained. On the other hand, an orientation degree A of 1.0 or more cannot be taken from the above formula (i) because the full width at half maximum ΔB always shows a positive value. When the range of the orientation degree A is 0.6 or more and less than 1.0, the polybenzazole molecular chain is sufficiently oriented in the polybenzazole complex, and the complex has an orientation direction of the polybenzazole molecular chain. Can exhibit an excellent anisotropic function, for example, excellent thermal conductivity.

  The polybenzazole composite of the present invention includes a semiconductor insulating film, a wiring board material, a sealant, a display alignment film, a polarizing film film base, a magnetic recording film base, a capacitor film, a solar cell, and a planar shape. Use in applications that require anisotropy in heating elements, electromagnetic wave countermeasure films, sensors, actuators, battery materials, mounting materials, gas barrier materials, laminated films, filters, separation membranes, ion exchange membranes, etc. Can do.

  In the case of the polybenzazole composite film 1 in which the polybenzazole composite is formed into a film shape, the thickness of the film is preferably 1 μm or more and 2 mm or less. When the thickness of the film is less than 1 μm, defects such as breakage tend to occur in the composite. On the other hand, when the thickness of the film exceeds 2 mm, it becomes difficult to form the film, and the production cost tends to increase.

The method for synthesizing the polybenzazole used in the present invention is disclosed in, for example, the above-mentioned Patent Document 4 and is well known, and thus the description thereof is omitted.
The concave portions 6b and the convex portions 6c on the surface 6a of the film-like substrate 6 are generated when the film-like substrate 6 is formed while the molecular chains of polybenzazole are highly oriented in the thickness direction. The recesses and projections as used herein mean that they include not only fine recesses and projections on the surface 6a of the film-like substrate 6 but also relatively large recesses and projections such as kinks, wrinkles, and swells. . As for the surface roughness of the film-like substrate 6, the arithmetic average roughness Ra is 0.1 μm to 5 μm, and the ten-point average roughness Rz is in the range of 5 μm to 30 μm.

  In the present invention, the elastic member 7 is provided so as to enter the recess 6 b of the surface 6 a of the film-like substrate 6, and improves the adhesion of the film-like substrate 6 to the attached body. The mounted body includes, for example, an electronic element in an electronic device. As shown in FIGS. 1A to 1C, the elastic member 7 is preferably laminated and formed as a single layer so as to completely fill the concave portion 6b and the convex portion 6c of the surface 6a of the film-like substrate 6. Yes. In this case, the surface 6a of the film-like substrate 6 can be flattened by the elastic member 7, and the adhesiveness to the mounted body can be further increased to obtain a lower thermal resistance. Further, as shown in FIGS. 2A and 2B, the elastic member 7 may be provided so as to form a substantially flush surface with the convex portion 6 c and the elastic member 7. Further, as shown in FIGS. 3A and 3B, the elastic member 7 may be formed so as to enter only the recess 6b so that the film-like substrate 6 is partially exposed. Even in these cases, the same effects as those of the elastic member shown in FIGS.

  As the material of the elastic member 7, an adhesive or a rubber-like elastic body can be used. Such an elastic member 7 can easily enter the recess 6 b of the film-like substrate 6. As the adhesive, for example, a synthetic rubber-based, silicone-based, acrylic-based, urethane-based, or ethylene-vinyl acetate-based adhesive can be used.

  When a rubber-like elastic body is used as the elastic member 7, a rubber-like elastic body having a type E hardness defined by Japanese Industrial Standard JIS K 6253: 2006 of 30 or less is preferable. This is because if the E hardness exceeds 30, the adhesion to the mounted body is deteriorated and it is difficult to reduce the thermal resistance value. As such a rubber-like elastic body, for example, silicone rubber, acrylic rubber, fluorine rubber, urethane rubber, butadiene rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber, or the like can be used. In consideration of polybenzazole having excellent heat resistance, it is preferable that the elastic member 7 also has heat resistance. Therefore, a silicone-based or fluorine-based pressure-sensitive adhesive or a rubber-like elastic body is preferably used. In addition, it is preferable to use a liquid rubber material so that the surface 6a of the film-like substrate 6 can easily enter the recess 6b.

  The thickness of the elastic member 7 is not uniform because the surface 6a of the film-like substrate 6 has the concave portions 6b and the convex portions 6c, but is preferably 40 μm or less on average. Here, the thickness of the elastic member 7 is a value obtained by subtracting the thickness of the film-like substrate 6 from the total thickness of the polybenzazole composite film 1. However, since the film-like substrate 6 has irregularities, the thickness of the elastic member 7 and the film-like substrate 6 differs depending on the measurement location, and thus the measurement was performed as follows. That is, immediately after applying the raw material of the elastic member 7 to the film-like substrate 6, a smooth biaxially stretched polyester film (trade name: Lumirror (registered by Toray Industries, Inc.) under the same application conditions (the same print conditions for printing) Trademark) and a thickness of 100 μm) were coated with the raw material of the elastic member 7 to form a control sample. The value obtained by subtracting the thickness of the polyester film alone (100 μm) from the total thickness of the control sample was taken as the thickness of the elastic member 7. If the thickness of the elastic member 7 exceeds 40 μm, the influence of the performance of the elastic member 7 on the entire polybenzazole composite film 1 becomes large, and the original performance of the film-like substrate 6 made of polybenzazole becomes difficult to be exhibited. is there. Moreover, it is preferable that the thickness of the elastic member 7 is a thickness that fills the concave portion 6 b of the surface 6 a of the film-like substrate 6.

  The elastic member 7 can further contain a powder of a heat conductive filler. Examples of the thermally conductive filler include aluminum oxide powder, boron nitride powder, aluminum nitride powder, magnesium oxide powder, zinc oxide powder, silicon carbide powder, quartz powder, aluminum hydroxide powder, and carbon fiber powder. . The proportion of the heat conductive filler is preferably 50 parts by weight or less with respect to 100 parts by weight of the raw material of the elastic member 7. When the proportion exceeds 50 parts by weight, the adhesiveness is lowered when a pressure-sensitive adhesive is used as the elastic member 7, and the flexibility is lowered when a rubber-like elastic body having an E hardness of 30 or less is used. .

  Further, the elastic member 7 may include a tackifier, a diluent solvent, a filler, a colorant, a flame retardant, an ultraviolet absorber, a light stabilizer, an anti-aging agent, a plasticizer, a leveling agent, an antistatic agent, as necessary. An antifoaming agent etc. can be contained.

Next, the manufacturing method of the polybenzazole composite film 1 is demonstrated.
Briefly speaking, the polybenzazole composite film 1 of the present invention includes a step of producing a film-like substrate 6 made of polybenzazole, and an elasticity that enters the surface 6a of the film-like substrate 6 into the recess 6b of the surface 6a. And the step of providing the member 7.

  First, a film-like substrate 6 made of polybenzazole is manufactured. The manufacturing method includes a step of preparing a polybenzazole solution, a step of orienting polybenzazole molecular chains in the thickness direction of the film-like substrate 6 by applying a magnetic field or an electric field to the polybenzazole solution, and And a step of solidifying the polybenzazole solution while maintaining the orientation state of the polybenzazole molecular chain to form a film-like substrate 6 made of polybenzazole.

  The process of preparing the polybenzazole solution is disclosed in, for example, Patent Document 4 described above, but will be briefly described. Solvents for preparing polybenzazole solutions include aprotic polar solvents such as N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, hexamethylphosphortriamide, polyphosphoric acid, Examples include methanesulfonic acid, cresol, and high-concentration sulfuric acid. These solvents may be used alone or in combination of two or more. Furthermore, a Lewis acid such as lithium bromide, lithium chloride, or aluminum chloride may be added to the solvent as a means for improving the solubility of both. The polybenzazole concentration in the polybenzazole solution is preferably high enough for the polybenzazole to exhibit liquid crystallinity in the polybenzazole solution. In order to easily orient polybenzazole molecular chains or mixed molecular chains containing polybenzazole, the polybenzazole concentration in the polybenzazole solution is preferably 2 to 30% by weight, more preferably 5 to 5% by weight. 25% by weight, more preferably 5 to 20% by weight.

  The maximum concentration of polybenzazole in the polybenzazole solution is mainly limited by physical factors such as the viscosity of polybenzazole and the polybenzazole solution. When the concentration of polybenzazole in the polybenzazole solution exceeds 30% by weight, the viscosity of the solution is too high and the molecular chains of polybenzazole are difficult to be oriented. If the polybenzazole concentration in the polybenzazole solution is less than 2% by weight, the polybenzazole solution cannot exhibit liquid crystallinity because the polybenzazole concentration is low. Therefore, since the effect of accelerating the orientation of the polybenzazole molecular chain by applying a magnetic field or the like is low, a sufficient anisotropic function may not be obtained in the polybenzazole complex 1 in some cases.

  The intrinsic viscosity of the polybenzazole that can be used in the present invention 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 It is -30 dl / g, More preferably, it is 0.5-20 dl / g, More preferably, it is 0.5-15 dl / g. When the intrinsic viscosity of a polybenzazole is less than 0.5 dl / g, such polybenzazole generally has a low molecular weight and is difficult to mold. 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 is too high and the polybenzazole molecular chain is hardly oriented.

  Polybenzazole solutions include glass fibers and other reinforcing materials, various fillers, pigments, dyes, fluorescent brighteners, dispersants, stabilizers, UV absorbers, antistatic agents, antioxidants, thermal stabilizers, and lubricants. A small amount of a plasticizer or the like may be added.

  As a method of forming the film-like substrate 6 from the polybenzazole solution, the polybenzazole solution is cast on the substrate by a method such as casting a polybenzazole solution from a die, for example, a slit die, onto the substrate, or by a casting method. Although there is a method of applying, it is not limited to these. At this time, as shown in FIG. 4, a polybenzazole solution is cast on the lower substrate 3 from the slit die, and another substrate 3 is stacked on the cast polybenzazole solution. The benzazole solution may be sandwiched between the two substrates 3. By sandwiching the polybenzazole solution between the two substrates 3 in this way, it is possible to prevent the polybenzazole solution from being deteriorated by contact with air.

  The substrate 3 is not particularly limited, but it is preferable to use a closed loop endless belt, an endless drum, an endless film or the like in order to obtain a long uniform film-like polybenzazole composite. Moreover, it is also possible to use plate-shaped objects, such as a glass plate and a resin film, as a board | substrate. The substrate may be made of metal, and stainless steel, hastelloy alloy, tantalum, etc. are particularly preferable.

  When the polybenzazole solution has lyotropic liquid crystallinity, the development of liquid crystallinity depends on both the solution concentration and temperature conditions. Therefore, before or during the alignment step, the polybenzazole solution may be heated as necessary to develop the liquid crystallinity of the polybenzazole solution. Specifically, the polybenzazole solution cast on the support surface is heated to a temperature range in which the solution exhibits liquid crystallinity. Alternatively, the polybenzazole solution is heated to a temperature range where the solution does not have liquid crystallinity, and once the polybenzazole solution is transferred to a uniform non-liquid crystal state, the temperature at which the solution has liquid crystallinity The temperature may be gradually lowered to the range. Thereby, the liquid crystal phase grown larger can be obtained. Or you may use together temperature rising and temperature falling as mentioned above sequentially. The heating is usually performed in a temperature range of 40 to 250 ° C, preferably 40 to 200 ° C, and most preferably 60 to 150 ° C. The heating means is not particularly limited, and examples thereof include a method of applying high-temperature humidified air to the intermediate, a method of irradiating ultraviolet rays from an ultraviolet lamp, and a method of dielectric heating.

  As a method for aligning the polybenzazole molecular chains, it is preferable to apply a magnetic field to the polybenzazole solution so that the magnetic lines of force are parallel to the alignment direction. 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 field is less than 1 T, the orientation of the polybenzazole molecular chain or the mixed molecular chain containing polybenzazole may be insufficient. On the other hand, when the magnetic flux density exceeds 30T, the cost for improving the magnetic flux density of the magnetic field increases.

  The polybenzazole solution can be solidified by simple evaporation of the solvent, but is preferably performed by using a coagulation liquid. This coagulation liquid is a substance that is compatible with the solvent of the polybenzazole solution and does not dissolve the polybenzazole. By bringing the coagulation liquid into contact with the polybenzazole solution, only the solvent in the polybenzazole solution is dissolved in the coagulation liquid, and as a result, the polybenzazole is solidified by precipitation. As a result, a polybenzazole film-like substrate 6 is obtained. According to the method using a coagulating liquid, polybenzazole can be coagulated more easily without the need for a heating device for evaporating the solvent or a device for collecting the evaporated solvent. In addition, when a strong acid such as polyphosphoric acid is used as a solvent, such a strong acid can be diluted by using a coagulating liquid, which is preferable in terms of safety.

  Substances that can be used as the coagulation liquid include water, phosphoric acid aqueous solution, sulfuric acid aqueous solution, sodium hydroxide aqueous solution, methanol, ethanol, acetone, ethylene glycol, and the like. You may mix and use. In addition, a magnetic field may be continuously applied during the solidification process in order to maintain the orientation of the polybenzazole molecular chain. Since the exchange of the coagulation liquid with the solvent of the polybenzazole solution is gentle and the surface 6a of the film-like substrate 6 can be easily prevented from being roughened, a 10 to 70% by weight phosphoric acid aqueous solution or lower alcohol is used as the coagulation liquid. It is particularly preferable to do this.

  The temperature of the coagulation liquid is preferably −60 to 60 ° C., more preferably −30 to 30 ° C., and most preferably 0 to 10 ° C. When the temperature of the coagulation liquid exceeds 60 ° C., the surface 6a of the film-like substrate 6 may be extremely rough, or the density may be different between the front and back of the molded body. Is slow and productivity decreases.

  The polybenzazole film-like substrate 6 obtained by coagulation of the polybenzazole solution is preferably washed before curing. The cleaning is performed, for example, by running a substrate that supports the film-like substrate 6 in a cleaning solution or by spraying the cleaning solution on the film-like substrate 6. Water is usually used as the cleaning liquid, but warm water may be used as necessary. First, the film-like substrate 6 may be neutralized and washed with an aqueous alkali solution such as sodium hydroxide or lithium hydroxide, and then washed with water or the like. The concentration of the acid component, amino basic component, and inorganic salt in the film-like substrate 6 after being washed is preferably 500 ppm or less. If the concentration of the acid component, amino basic component and inorganic salt after washing exceeds 500 ppm, the film-like substrate 6 will be deteriorated (decomposed), and the properties of the polybenzazole composite film 1 finally obtained will be impaired. This is not preferable.

  The method for curing the solidified film-like substrate 6 is not particularly limited, but includes a method using a heated gas such as air, nitrogen or argon, a method using radiant heat such as an electric heater or an infrared lamp, and a dielectric heating method. And drying by heating. In the case where polybenzazole or a mixed molecule containing polybenzazole contains a photocrosslinkable molecule, a crosslinking reaction by light irradiation may be mentioned.

  When the film-like substrate 6 is cured, the outer edge portion thereof may be constrained to limit the shrinkage of the film-like substrate 6. The temperature for curing the film-like substrate 6 is preferably 100 to 500 ° C, more preferably 100 to 400 ° C, and most preferably 100 to 200 ° C. If it is less than 100 degreeC, since the film-form base | substrate 6 is hard to harden | cure, it is not preferable.

  In the present invention, the molding step and the subsequent steps such as heating, magnetic field orientation, solidification, washing, impregnation, and curing may be performed continuously, or all or some of these steps may be performed intermittently, that is, You may go batch-wise.

Hereinafter, according to FIG. 4, the manufacturing method of the polybenzazole composite film 1 is demonstrated in detail.
First, a polybenzazole solution used in the present invention is prepared. The polybenzazole solution is preferably in a concentration range in which the polybenzazole has a liquid crystal state. Next, the solution is cast on a lower substrate 3 from a slit die (not shown), another substrate 3 is overlaid on the cast solution, and the solution is separated into two sheets. By sandwiching between the base materials 3, the film intermediate body 2 in which the solution is formed into a film shape having a certain thickness is formed.

  Next, as shown in FIG. 4, a pair of permanent magnets 4 is disposed as a magnetic field generator above and below the base material 3, and a magnetic field is applied to the film intermediate 2. The N pole and S pole of the pair of permanent magnets 4 are arranged so as to face each other so that the lines of magnetic force 5 are along the thickness direction of the film intermediate 2.

  Thereby, the polybenzazole molecular chain in the film intermediate 2 is oriented in the thickness direction of the film intermediate 2. At this time, a heating device (not shown) is provided on both sides of the substrate 3, and the film intermediate 2 is maintained in a temperature range in which the solution exhibits a liquid crystal state. While the orientation state is maintained, the film intermediate 2 is solidified to form the film-like substrate 6 made of polybenzazole. Thereafter, by curing the film-like substrate 6, the polybenzazole molecular chain is oriented in the thickness direction of the film-like substrate 6, and the film-like substrate 6 made of polybenzazole having an excellent anisotropic function in that direction is obtained. Obtainable.

  Here, when the film-like substrate 6 is obtained, if the film is formed by a mechanical method such as stretching, the polybenzazole molecular chain oriented in the thickness direction acts so as to be oriented along the stretching direction. Thus, the orientation in the thickness direction is impaired. Therefore, as described above, the film-like substrate 6 is manufactured by solidifying the polybenzazole solution while maintaining the orientation of the polybenzazole molecular chain in the thickness direction. Since the film is formed while maintaining the orientation of the molecular chain in the thickness direction, it is difficult to obtain a film-like substrate 6 having a smooth surface 6a, and the concave portion 6b and the convex portion 6c caused by the surface 6a or wrinkles are difficult. Is formed. The following can be considered as the cause.

  In the process from the step of orienting the polybenzazole molecular chains in the thickness direction to the step of forming the film-like substrate 6 by solidifying the polybenzazole solution while maintaining the alignment state of the molecular chains, the polybenzazole In the solution state, a solvent exists around the molecular chain oriented in the thickness direction. When this solvent is removed in the coagulation step, it is considered that the molecular chain approaches to make up for the removed space and contraction occurs. At that time, the molecular chains are not uniform in length, and the forces acting between the molecular chains (such as intermolecular forces) are considered to be different. Therefore, it is considered that each molecular chain is difficult to contract in an orderly manner and is accompanied by twists and wrinkles.

  In the absence of the elastic member 7, the surface 6a of the film-like substrate 6 is in direct contact with the mounted body due to the influence of the concave portion 6b and the convex portion 6c of the surface 6a, so that a good contact state cannot be obtained. The heat resistance value expected from the original heat conduction performance cannot be obtained. In the present embodiment, the elastic member 7 is provided in order to fill the concave and convex portions and reduce the thermal resistance value.

  As a method of providing the elastic member 7, means such as printing, painting, and dipping can be adopted. As a printing method, screen printing, gravure printing, pad printing, and the like, spray coating, roll coater, Examples include bar coaters and blade coaters.

According to this embodiment, the following effects can be obtained.
(1) The film-like substrate 6 has polybenzazole molecular chains oriented in the thickness direction, and a concave portion 6b and a convex portion 6c are formed on the surface 6a of the film-like substrate 6. Since the elastic member 7 that enters the recess 6b is provided in the film-like substrate 6, the film-like substrate surface 6a is flattened and the adhesion to the attached body is enhanced. Here, if only the film-like substrate made of polybenzazole is provided on the attached body, air is interposed between the film-like substrate and the attached body due to the unevenness of the film-like substrate. However, according to the polybenzazole composite of the present invention, by providing the elastic member, the place where air has conventionally been interposed is replaced with the elastic member. Thereby, the thermal resistance of the polybenzazole complex can be lowered. Therefore, application development is possible as a heat conductive member having excellent heat resistance derived from polybenzazole.

  For example, a film formed of polybenzazole can be used as an application in which heat from a heating element is transmitted to a radiator and the heating element is radiated (cooled). However, not only for the above applications, but also for applications in which the heat of the polybenzazole is utilized to efficiently transfer the heat of the heater to the heated member in the heated member heated by a heater or the like. A benzazole complex can be used.

  (2) Since the elastic member 7 is formed of an adhesive, it can be easily adhered and positioned with respect to the mounted body. In addition, application development is possible as a heat conductive pressure-sensitive adhesive tape having excellent heat resistance derived from polybenzazole.

  (3) Since the elastic member 7 is a rubber-like elastic body having a type E hardness of 30 or less as defined in JIS K 6253, the adhesion to the mounted body is increased and the thermal resistance of the polybenzazole composite film 1 is reduced. can do. Further, if a rubber-like elastic body of a thermosetting resin is used, it can be used even at high temperatures, and it can be applied to a field utilizing the excellent heat resistance characteristics of polybenzazole.

(4) Since the elastic member 7 includes a heat conductive filler, the heat conductivity of the elastic member 7 itself can be improved, and the heat conductivity of the polybenzazole composite can be further improved.
(5) By setting the thickness of the elastic member 7 to 40 μm or less, the original thermal properties of the film-like substrate 6 made of polybenzazole can be easily exhibited.

The embodiment described above can be modified as follows.
The poly benz film-shaped substrate 6 azole, 0.99 ° C. to 300 ° ^C., after the heat compression process in 0.3N / cm ² ~1.5N / cm 2 as low load condition, and an elastic member 7 Also good. The elastic member 7 is provided in such a state that the orientation state of the molecular chains in the thickness direction of the film-like substrate 6 is not impaired by the low-load pressure compression processing and the twist of the film-like substrate 6 is relaxed. Can do.

  As shown in FIGS. 5A and 5B, a peelable protective layer 8 such as a release sheet may be further laminated on the surface of the elastic member. By providing the protective layer 8, it is possible to improve the difficulty of manufacturing, transporting, and attaching the polybenzazole complex due to the adhesiveness of the elastic member 7, and to suppress deformation of the polybenzazole complex 1. be able to.

  In the above embodiment, the elastic member 7 is provided only on the one surface 6a side of the film-like substrate 6, but as shown in FIGS. 6 (a) and 6 (b), it is elastic on both surfaces of the film-like substrate 6. The member 7 may be provided.

Next, the embodiment will be described more specifically with reference to examples and comparative examples.
Example 1
In Example 1, polybenzoxazole in which Ar ₁ and Ar ₂ are both benzene rings and X is an oxygen atom in the formula (1) was synthesized as polybenzazole. 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 (23.4 mmol) of 4,6-diaminoresorcinol dihydrochloride, terephthalic acid dichloride 4.76 g (23.4 mmol) and a predetermined amount of benzoyl chloride were charged and stirred at 70 ° C. for 16 hours. Further, while stirring the solution, the temperature was increased stepwise in the order of 5 hours at 90 ° C, 3 hours at 130 ° C, 16 hours at 150 ° C, 3 hours at 170 ° C, 3 hours at 185 ° C, 48 hours at 200 ° C. 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 3 dl / g. Polyphosphoric acid was added to the obtained polybenzoxazole to prepare a polybenzoxazole solution having a final concentration of 10 wt%. Here, the polybenzoxazole solution was observed using a polarizing microscope, and it was confirmed that the polybenzoxazole solution exhibited liquid crystallinity.

  As shown in FIG. 4, the polybenzoxazole solution was apply | coated between the two base materials 3, and the film intermediate body 2 was shape | molded. Next, a pair of magnets 4 was disposed above and below the base material 3 so that the magnetic lines of force 5 were parallel to the thickness direction of the film intermediate 2. Thereby, while applying a magnetic field of 8 Tesla to the film intermediate 2, it was heated at 120 ° C. for 60 minutes, further naturally cooled to room temperature, and allowed to stand. Thereafter, the film intermediate 2 was taken out from between the magnets 4 while being sandwiched between the substrates 3 and immersed in a mixed solution of methanol and water. In the mixed solution, one of the substrates 3 was removed, and the film intermediate 2 was solidified to obtain a polybenzoxazole substrate. The polybenzoxazole substrate was immersed in the same mixed solution for 1 hour as it was, then immersed in water for 1 hour and further in acetone for 1 hour. Then, it dried at 120 degreeC for 2 hours, and obtained the film-form base | substrate 6 which consists of polybenzoxazole. Here, the application direction of the magnetic field coincides with the Z-axis direction shown in FIG. 1 with respect to the film intermediate 2 spreading on the substrate.

Next, an adhesive was laminated as the elastic member 7. 70 parts by weight of TSR1512 pressure-sensitive adhesive manufactured by Momentive Performance Materials, 7 parts by weight of CR50 curing agent as a silicone-based pressure-sensitive adhesive, and 30 parts by weight of silicone gel CY52-276A & B manufactured by Toray Dow Corning Silicone as a physical property adjusting agent were mixed. The obtained mixture was applied to a polybenzoxazole film-like substrate 6 by screen printing to form an adhesive layer, whereby a polybenzoxazole composite film 1 was obtained. The thickness of the pressure-sensitive adhesive layer of the obtained composite was an average of 10 μm.
(Example 2)
In Example 2, a polybenzoxazole composite film was obtained by the same method as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was 20 μm on average.
(Example 3)
In Example 3, a polybenzoxazole composite film was obtained by the same method as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was an average of 40 μm.
Example 4
In Example 4, the pressure-sensitive adhesive is a synthetic rubber-based pressure-sensitive adhesive (KIWOPRINT TC-2000 manufactured by Jujo Chemical Co., Ltd.), and the thickness of the pressure-sensitive adhesive layer is 20 μm on average. A benzoxazole composite film was obtained.
(Example 5)
In Example 5, the pressure-sensitive adhesive was an acrylic pressure-sensitive adhesive (CAT-1400S pressure-sensitive adhesive manufactured by Teikoku Ink Co., Ltd.), and the thickness of the pressure-sensitive adhesive layer was 20 μm on average. A benzoxazole composite film was obtained.
(Example 6)
In Example 6, a polybenzoxazole composite was prepared in the same manner as in Example 1 except that 10 parts by weight of thermally conductive filler (spherical alumina AH3-2 manufactured by Micron) was blended with 100 parts by weight of the adhesive. A film was obtained.
(Example 7)
In Example 7, a rubber-like elastic material was laminated as the elastic member 7 on the same polybenzoxazole film as in Example 1. A polybenzoxazole composite in which an addition type silicone gel CY52-290A & B manufactured by Toray Dow Corning Silicone Co., Ltd. is used as a rubber-like elastic body, which is applied to a film-like substrate made of polybenzoxazole with a bar coater, and a silicone rubber layer is laminated. A film was obtained. The silicone rubber layer had an E hardness of 14 and an average thickness of 20 μm.
(Example 8)
In Example 8, a polybenzoxazole composite film was obtained in the same manner as in Example 7 except that the E hardness of the silicone rubber layer of the rubbery elastic body was 28.
Example 9
In Example 9, a polybenzoxazole composite film was obtained by the same method as in Example 7 except that urethane rubber was used as the rubber-like elastic body. The urethane rubber is composed of 50 parts by weight of hydrogenated polyisoprene polyol EPOL manufactured by Idemitsu Kosan Co., Ltd., 50 parts by weight of hydrogenated polybutadiene polyol KRASOLHLBH-P3000 manufactured by Sartomer, USA, 200 parts by weight of polyalphaolefin PAO5010 manufactured by Idemitsu Kosan, and poly Isocyanate Dismodule W was added so that the NCO / OH molar ratio was 1.05, and 0.01 parts by weight of Kyodo Kagaku dibutyltin dilaurate was added as a reaction catalyst, and the mixture was stirred and mixed.
(Comparative example)
In the comparative example, only the film-like substrate 6 made of polybenzoxazole obtained in Example 1 was used.
(Evaluation methods)
<Measurement of thermal resistance value>
Samples were prepared by cutting the sheet of each example into 10 mm length × 10 mm width. The sample of each example was sandwiched between a heat generating substrate (heat generation amount Q: 25 W) and a heat sink (“FH60-30” manufactured by Alpha Co., Ltd.), and a constant load (4 kgf / cm ² ) was applied to the heat sink. A cooling fan (air volume 0.01 kg / sec, wind pressure 49 Pa) is attached to the upper part of the heat sink, and a temperature sensor is connected to the heat sink and the heat generating board. The heating substrate is energized with the cooling fan activated. When 10 minutes passed after the start of energization, the temperature of the heat generating substrate (T1) and the temperature of the heat sink (T2) were measured, and the thermal resistance value was calculated by substituting each temperature into the following equation.
Thermal resistance value (° C / W) = (T1-T2) / Heat generation amount Q

熱抵抗測定結果を表１及び２に示す。この結果から明らかなように、各実施例の熱抵抗値は、弾性材料を積層していない比較例の熱抵抗値より低い値を示している。これは流れ性や柔軟性を有した弾性部材によって被取付体との高度な密着が可能となり、熱伝導性能が向上したためと考えられる。

The thermal resistance measurement results are shown in Tables 1 and 2. As is clear from this result, the thermal resistance value of each example is lower than the thermal resistance value of the comparative example in which the elastic material is not laminated. This is presumably because the elastic member having flowability and flexibility enables a high degree of close contact with the mounted body and improves the heat conduction performance.

  On the other hand, since the elastic material is not laminated in the comparative example, the concave portion 6b and the convex portion 6c of the surface 6a of the film-like substrate 6 hinder the adhesion between the film-like substrate 6 and the mounted body, and the thermal resistance value is high. The value is shown.

(A) is a perspective view which shows one Embodiment of the polybenzazole complex of this invention, (b) is the sectional drawing, (c) is the elements on larger scale of (b). Sectional drawing which shows another embodiment of the polybenzazole complex of this invention, and corresponds to FIG.1 (b) and (c). Sectional drawing which shows another embodiment of the polybenzazole composite_body | complex of this invention, and corresponds to FIG.1 (b) and (c). Schematic which shows the manufacturing method of the film-form base | substrate which consists of polybenzazole by which the molecular chain which comprises a polybenzazole composite body was orientated in the thickness direction. (A) is a perspective view which shows another embodiment of the polybenzazole complex of this invention, (b) is the sectional drawing. (A) is a perspective view which shows another embodiment of the polybenzazole complex of this invention, (b) is the sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polybenzazole composite, 2 ... Film intermediate body, 3 ... Base material, 4 ... Permanent magnet, 5 ... Magnetic field line, 6 ... Film-like base | substrate, 6a ... Surface, 6b ... Concave part, 6c ... Convex part, 7 ... Elasticity Member, 8 ... protective layer.

Claims (5)

The following general formulas (1) to (4) (wherein X represents a sulfur atom, oxygen atom or imino group, Ar ₁ and Ar ₂ represent aromatic hydrocarbon groups, and n is an integer of 10 to 500). And a film-like substrate having a polybenzazole molecular chain oriented in the thickness direction and having a plurality of recesses formed on the surface thereof. A polybenzazole composite comprising an elastic member that enters a recess of a film-like substrate.

The polybenzazole complex according to claim 1, wherein the elastic member is made of an adhesive. The polybenzazole composite according to claim 1, wherein the elastic member is a rubber-like elastic body having a type E hardness of 30 or less as defined in JIS K 6253. The polybenzazole composite according to any one of claims 1 to 3, wherein the elastic member includes a heat conductive filler. The polybenzazole complex according to any one of claims 1 to 4, wherein the elastic member has a thickness of 40 µm or less.

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