JP2007262312A - Polyarylate, optical film and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylate low in linear thermal expansion coefficient, excellent in transparency, having heat resistance capable of forming various functional layers at elevated temperature, and excellent mechanical properties for film forming. <P>SOLUTION: The polyarylate has a structure represented by either of general formula in the figure, and an optically active site (ring α, β, and γ are each a single ring or a polycyclic ring.). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyarylate excellent in heat resistance and transparency and having a low linear thermal expansion coefficient, and an optical film using the polyarylate. Furthermore, the present invention relates to an image display device using these optical films and having excellent display quality.

  In recent years, in the field of flat panel displays such as liquid crystal display elements and organic electroluminescence elements (hereinafter referred to as “organic EL elements”), the substrate is replaced from glass to plastic in order to improve breakage resistance, reduce weight, and reduce thickness. Is being considered. In particular, there is a strong demand for plastic substrates in the field of mobile information communication device display devices such as mobile phones, electronic notebooks, laptop computers, and other portable information terminals.

  The plastic substrate needs to have conductivity. Therefore, in recent years, on a plastic film, a semiconductor film such as an oxide of indium oxide, tin oxide, or tin-indium alloy, a metal film such as an oxide film of gold, silver, or palladium alloy, or the semiconductor film and the metal film Research has been conducted on the use of a plastic substrate on which a transparent conductive layer made of a composite film in combination with is used as an electrode substrate of a display element. Specifically, heat-resistant amorphous polymer (for example, modified polycarbonate (modified PC) (for example, see Patent Document 1), polyethersulfone (PES) (for example, see Patent Document 2), cycloolefin copolymer (for example, patent) There is known a plastic substrate in which a transparent conductive layer and further a gas barrier layer are laminated on a plastic film made of literature 3)).

However, even if the heat-resistant plastic film as described above is used, a plastic substrate having sufficient heat resistance cannot be obtained. That is, when a conductive layer is formed on these heat-resistant plastic films and then exposed to a temperature of 150 ° C. or higher for providing an alignment film or the like, there is a problem that the conductivity and gas barrier properties are greatly lowered.
On the other hand, in recent years, it is inevitable that the plastic substrate is exposed to higher temperatures when installing TFTs for the production of active matrix type image elements, and the plastic substrate is required to have a higher level of heat resistance. It has come to be.

Therefore, a method has been proposed in which the temperature at the time of manufacturing the image element is set to 300 ° C. or less in consideration of the burden on the plastic substrate. For example, as a method for exposing to a temperature of 300 ° C. or lower, a method of forming a polycrystalline silicon film at a temperature of 300 ° C. or lower by plasma decomposition of a gas containing SiH ₄ (see Patent Document 4), an energy beam, or the like. Is used to form a semiconductor layer in which amorphous silicon and polycrystalline silicon are mixed on a polymer substrate (see Patent Document 5), or a thermal buffer layer is provided and irradiated with a pulsed laser beam at 300 ° C. A method of forming a polycrystalline silicon semiconductor layer on a plastic substrate at the following temperature (see Patent Document 6) is known. However, these methods for forming TFTs at 300 ° C. or lower have a problem that the configuration and apparatus are complicated and the cost is high.

  Therefore, it is actually desired to form TFTs at a high temperature of 300 ° C. or higher, and it is required to provide a plastic substrate having heat resistance of 300 ° C. or higher. Furthermore, TFT formation at a higher temperature is required in order to stably develop the electrical characteristics of the TFT. For this reason, it is desired to provide a plastic substrate having more excellent heat resistance from the viewpoint of reducing the number of defective products.

  On the other hand, studies have been made on 9,9-bis (4-hydroxyphenyl) fluorene (hereinafter also referred to as “bisphenolfluorene”) and polyarylate films derived from isophthalic acid and terephthalic acid (for example, Patent Document 7 and (See Patent Document 8). Further, studies have been made on polyarylate films derived from alkyl-substituted bisphenolfluorenes, isophthalic acid and terephthalic acid (for example, see Patent Document 9). Polyarylates derived from these substituted or unsubstituted bisphenolfluorenes and isophthalic acid and terephthalic acid can be synthesized from inexpensive raw materials, and have a glass transition temperature (Tg) of around 300 ° C. or higher. Therefore, it is possible to provide a flexible film excellent in transparency and elongation at break. However, none of these films can satisfy the above-mentioned heat resistance requirement required for a plastic substrate.

  In addition, it is known that control of stereoregularity such as tacticity in polymethacrylic acid has a great influence on physical properties such as glass transition temperature, and precise control of stereoregularity has attracted attention from the viewpoint of improving physical properties. ing. Furthermore, in recent years, there has been reported an example in which stereoregularity is controlled by introducing axial chirality into the polymer main chain to improve the glass transition temperature. However, even in such an example, the glass transition temperature has not been improved so as to sufficiently satisfy the above requirements (see, for example, Non-Patent Document 1).

JP 2000-227603 A (all pages) JP 2000-284717 A (all pages) JP 2001-150584 A (all pages) JP-A-7-81919 (all pages) Japanese National Patent Publication No. 10-512104 (all pages) Japanese Patent Laid-Open No. 11-102867 (all pages) JP-A-57-192432 (all pages) JP-A-3-28222 (all pages) WO99 / 18141 pamphlet (all pages) J. Polym. Sci., PartA; Polym. Chem. 42, 4318 (2004)

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to have a low coefficient of linear thermal expansion, excellent transparency, heat resistance and film formation capable of forming various functional layers at high temperatures. It is to provide a polyarylate having excellent mechanical properties that can be achieved, and to provide an optical film using such a polyarylate.
Still another object of the present invention is to provide an image display device using the optical film and having excellent display quality.

  As a result of intensive studies on the structure of polyarylate in order to achieve the above object, the present inventor has the heat resistance required for a plastic substrate used as an image display element as long as it is a polyarylate having a specific repeating unit. The inventors have found that transparency and mechanical properties can be obtained, and have completed the present invention.

That is, the said subject of this invention is achieved by the following means.
(1) A polyarylate having at least one of the structures represented by the following general formula (1) or (2) in the main chain and an optically active site.

［一般式（１）中、環αは単環式または多環式の環を表し、２つの環αはそれぞれ同じであっても異なっていてもよい。２つの環αは、スピロ結合により連結されている。］

[In general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings α may be the same or different. The two rings α are connected by a spiro bond. ]

［一般式（２）中、環βおよび環γは、単環式または多環式の環を表し、２つの環γはそれぞれ同じであっても異なっていてもよい。２つの環γは、環β上の１つの４級炭素に連結されている。］

[In general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Two rings γ are linked to one quaternary carbon on ring β. ]

(2) The polyarylate according to (1), wherein the optically active site has axial chirality.

(3) The polyarylate according to (1) or (2), wherein the optically active site having axial chirality has a structure represented by the following general formula (3).

［一般式（３）中、環δは、単環式または多環式の環を表し、２つの環δはそれぞれ同じであっても異なっていてもよい。２つの環δは、単結合により直結されている。］

[In general formula (3), ring δ represents a monocyclic or polycyclic ring, and the two rings δ may be the same or different. The two rings δ are directly connected by a single bond. ]

(4) The position where the two rings δ in the general formula (3) are each bonded to the main chain is the α-position or β-position of the carbon atom forming the single bond. Polyarylate.

(5) The polyarylate according to (1) or (2), wherein the optically active site having axial chirality has a structure represented by the following general formula (8).

［一般式（８）中、Ｒ⁵¹、Ｒ⁵²はそれぞれ独立に置換基を表す。Ｒ⁵¹、Ｒ⁵²で表わされる置換基が複数ある場合、それぞれの置換基は同じであっても異なっていてもよく、それぞれが連結して環を形成してもよい。ｍおよびｎはそれぞれ独立に０〜６の整数を表す。］

[In General Formula (8), R ⁵¹ and R ⁵² each independently represents a substituent. When there are a plurality of substituents represented by R ⁵¹ and R ⁵² , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 6. ]

(6) The polyarylate according to any one of (1) to (5), wherein the glass transition temperature is 250 ° C. or higher.
(7) An optical film comprising the polyarylate according to any one of (1) to (6).
(8) The optical film as described in (7), which is obtained by stretching at a draw ratio of 1.1 to 5.0 times in a uniaxial or biaxial direction.
(9) The optical film according to (7) or (8), wherein the linear thermal expansion coefficient at 0 to 200 ° C. is 50 ppm / ° C. or less.

(10) The optical film as described in any one of (7) to (9), wherein the total light transmittance is 80% or more.

(11) An optical film comprising a gas barrier layer on the optical film according to any one of (7) to (10).
(12) An optical film comprising a transparent conductive layer on the optical film according to any one of (7) to (11).
(13) An image display device comprising the optical film according to any one of (7) to (12).

  According to the present invention, polyarylate having a low coefficient of linear thermal expansion, heat resistance capable of forming various functional layers at high temperatures, and excellent transparency and excellent mechanical properties capable of forming a film, and In addition, an optical film using the same and an image display device excellent in display quality can be provided.

  Hereinafter, the polyarylate and the optical film of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Polyarylate]
The polyarylate of the present invention has at least one structure represented by the following general formula (1) or (2) and an optically active site in the main chain.
The structure represented by the following general formula (1) or (2) is contained in either the diol monomer unit or the dicarboxylic acid monomer unit forming the polyarylate, but may be contained in both. The polyarylate of the present invention may have two or more diol monomer units having a structure represented by the general formula (1) or (2), or represented by the general formula (1) or (2). Two or more types of dicarboxylic acid monomer units having the structure described above may be included. These combinations can be arbitrarily selected.

  The polyarylate of the present invention is obtained by copolymerizing an optically active site with a partial structure forming a highly heat-resistant amorphous polymer having excellent transparency and solubility represented by the following general formula (1) or (2). It is possible to control the stereoregularity of the whole molecule, improve the orientation of the molecule, and suppress the linear thermal expansion. As a result, it has become possible to provide a polyarylate having excellent transparency and heat resistance and a low linear thermal expansion coefficient.

  In the following general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings α may be the same or different. The two rings α are connected by a spiro bond.

  In the following general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Two rings γ are linked to one quaternary carbon on ring β.

Examples of the monocyclic or polycyclic ring represented by ring α, ring β and ring γ in general formulas (1) and (2) include, for example, indane Ring, chroman ring, 2,3-dihydrobenzofuran ring, indoline ring, tetrahydropyran ring, tetrahydrofuran ring, dioxane ring, cyclohexane ring, cyclopentane ring and the like.
Examples of the ring β in the general formula (2) include a fluorene ring, an indandione ring, an indanone ring, an indene ring, an indane ring, a tetralone ring, an anthrone ring, a cyclohexane ring, a cyclopentane ring, and the like.
The ring γ in the general formula (2) includes a benzene ring, naphthalene ring, anthracene ring, fluorene ring, cyclohexane ring, cyclopentane ring, pyridine ring, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, benzothiazole ring, Indane ring, chroman ring, indole ring, α-pyrone ring and the like can be mentioned.

  Preferred examples of the linking group structure having a spiro structure represented by the general formula (1) include a spirobiindane structure represented by the following general formula (4), a spirobichroman structure represented by the following general formula (5), And the spirobibenzofuran structure represented by following General formula (6) is mentioned.

In the general formula (4), R ¹¹ and R ¹² each independently represents a hydrogen atom or a substituent, and R ¹³ represents a substituent. When there are a plurality of substituents represented by R ^{11 to} R ¹³ , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 3. Examples of preferred substituents include a halogen atom, an alkyl group, or an aryl group. More preferred examples of R ¹¹ and R ¹² are hydrogen atom, methyl group or phenyl group, and more preferred examples of R ¹³ are fluorine atom, chlorine atom, bromine atom, methyl group, trifluoromethyl group, isopropyl group. Group, tert-butyl group or phenyl group.

In the general formula (5), R ²¹ represents a hydrogen atom or a substituent, and R ²² represents a substituent. When there are a plurality of substituents represented by R ²¹ and R ²² , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 3. Examples of preferred substituents include a halogen atom, an alkyl group, or an aryl group. More preferred examples of R ²¹ are hydrogen atom, methyl group or phenyl group, and more preferred examples of R ²² are fluorine atom, chlorine atom, bromine atom, methyl group, trifluoromethyl group, isopropyl group, tert-butyl. Group or phenyl group.

In the general formula (6), R ³¹ represents a hydrogen atom or a substituent, and R ³² represents a substituent. When there are a plurality of substituents represented by R ³¹ and R ³² , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 3. Examples of preferred substituents include a halogen atom, an alkyl group, or an aryl group. More preferred examples of R ³¹ are hydrogen atom, methyl group or phenyl group, and more preferred examples of R ³² are fluorine atom, chlorine atom, bromine atom, methyl group, trifluoromethyl group, isopropyl group, tert-butyl. Group or phenyl group.

  Moreover, the preferable example of the coupling group which has a cardo structure represented by General formula (2) includes the fluorene structure represented by the following general formula (7).

In the general formula (7), R ⁴¹ and R ⁴² each independently represent a substituent. When there are a plurality of substituents represented by R ⁴¹ and R ⁴² , the respective substituents may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 4. Examples of preferred substituents include a halogen atom, an alkyl group, or an aryl group. More preferred examples of R ⁴¹ and R ⁴² are fluorine atom, chlorine atom, bromine atom, methyl group, trifluoromethyl group, isopropyl group, tert-butyl group or phenyl group.

  Next, the optically active site of the polyarylate of the present invention will be described. The type of optical activity may be one having an asymmetric center, one having axial chirality, or one having planar chirality.

  It is more preferable that the polyarylate of the present invention has an axial chirality particularly at the optically active site, and the site having the axial chirality may have a structure represented by the following general formula (3). More preferred. In general formula (3), ring δ represents a monocyclic or polycyclic ring, and the two rings δ may be the same or different. The two rings δ are directly connected by a single bond.

Preferred examples of the ring δ in the general formula (3) include a benzene ring, naphthalene ring, anthracene ring, tetralin ring, fluorene ring, cyclohexane ring, cyclopentane ring, pyridine ring, furan ring, benzofuran ring, thiophene ring, benzothiophene. Ring, benzothiazole ring, indane ring, chroman ring, indole ring, α-pyrone ring and the like.
The two rings δ in the general formula (3) are bonded to each other through a single bond, but the positions where the two rings δ are bonded to the main chain are the α-position or β-position of the carbon atom forming the single bond. It is preferable that both are in the α-position.

  Moreover, as a preferable example of the axial chirality structure represented by General formula (3), the binaphthyl structure represented by following General formula (8) is mentioned. In the general formula (8), the structure represented by the (R) isomer is used, but the (S) isomer, any mirror image, or a mixture of both may be used.

In the general formula (8), R ⁵¹ and R ⁵² each independently represent a substituent. When there are a plurality of substituents represented by R ⁵¹ and R ⁵² , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 6. Preferable examples of the substituent represented by R ⁵¹ and R ⁵² include a hydrogen atom, a halogen atom, an alkyl group or an aryl group, more preferably a hydrogen atom, a methyl group, a fluorine atom or a chlorine atom, a hydrogen atom, A methyl group is particularly preferred.

  The polyarylate of the present invention comprises one or more monomers (dicarboxylic acid derivatives, diols, etc.) having a unit structure represented by the general formula (1) or (2), and a monomer (dicarboxylic acid derivative) having an optically active site. Diol, etc.) and dicarboxylic acid derivatives other than these as required (for example, terephthalic acid, terephthalic acid chloride, isophthalic acid, isophthalic acid chloride, 2,6-naphthalenedicarboxylic acid, 2,6 -Naphthalenedicarboxylic acid chloride, 4,4'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid chloride, etc.), diol (hydroquinone, 2,6-naphthalenediol, 4,4'-dihydroxybiphenyl, etc.) or hydroxy Carboxylic acid (hydroxybenzoic acid, hydroxynaphth The combination of one or more monomers of Renkarubon acid etc.) and the like, can be obtained by performing polycondensation.

  The repeating unit having the structure represented by the general formula (1) or (2) is preferably contained in the range of 5 to 100 mol% in the polyarylate of the present invention, and contained in the range of 10 to 100 mol%. It is more preferable that it is contained in the range of 20 to 100 mol%.

  The repeating unit having an optically active site is preferably contained in the range of 1 to 50 mol%, more preferably in the range of 1 to 40 mol%, and more preferably 1 to 30 mol in the polyarylate of the present invention. % Is particularly preferable.

  The repeating unit having an optically active site may be a single enantiomer or a mixture of each single enantiomer, but the enantiomeric excess ((| R−S | / | R + S |) × 100) The range is preferably 1 to 100% ee, more preferably 5 to 100% ee, and particularly preferably 10 to 100% ee.

  When other polymerization components are copolymerized, the content of the other polymerizable component is preferably in the range of 0 to 70 mol%, more preferably in the range of 0 to 60 mol%, and particularly preferably in the range of 0 to 50 mol%. preferable.

  Although the specific example (exemplary compound P-1 to P-30) of the polyarylate of this invention is illustrated below, the polyarylate which can be employ | adopted by this invention is not limited to these. In addition, the number of a repeating unit represents copolymerization ratio (mol%).

  The polyarylate of the present invention can be obtained by polycondensation of the corresponding bisphenol compound and dicarboxylic acid. The polycondensation method includes a melt polycondensation method using deacetic acid, a melt polycondensation method using dephenol, and a dehydrochlorination homogeneous polymerization method in which an organic base is used as an acid chloride with a dicarboxylic acid compound as an acid chloride and the polymer is soluble Any known method such as an interfacial polycondensation method using a dicarboxylic acid compound as an acid chloride in a two-phase system of an aqueous alkali solution and a water-immiscible organic solvent may be used. When synthesizing the polyarylate of the present invention having a Tg of 300 ° C. or higher, melt polycondensation is difficult, but by using a high-boiling plasticizer together as described in JP-A-7-188405, Polymerization may be performed at a reaction temperature of about 300 ° C.

  When synthesizing the polyarylate of the present invention, the interfacial polycondensation method is simple and preferable. As a typical known interfacial polycondensation method, bisphenol A and a bisphenol compound are solubilized in an aqueous alkaline solution as represented by a method using terephthalic acid or isophthalic acid, and dicarboxylic acid chloride is mixed with water-immiscible organic material. A method of mixing in a short time by solubilizing in a solvent (typically dichloromethane or the like) is employed. However, in the present invention, the solubility of the bisphenol compound in an alkaline aqueous solution may be low. In addition, acid halides such as 2,6-naphthalenedicarboxylic acid chloride have low solubility in water-immiscible organic solvents, and high molecular weight polyarylate may not be synthesized by known methods. In this case, a method in which water, a water-immiscible organic solvent, a bisphenol compound, and a dicarboxylic acid chloride are mixed and stirred in a slurry state and a high-concentration alkaline aqueous solution is gradually added is effective for increasing the molecular weight.

  The preferred molecular weight of the polyarylate of the present invention is 10,000 to 500,000, more preferably 20,000 to 300,000, particularly preferably 30,000 to 200,000 in terms of weight average molecular weight. If the molecular weight is too low, film formation may be difficult and mechanical properties may be deteriorated. If the molecular weight is too high, it may be difficult to control the molecular weight in the synthesis, or the solution may be too viscous to be handled. The molecular weight can be based on the corresponding viscosity.

  The molecular weight of the polyarylate of the present invention can be adjusted by adding a monofunctional substance at the time of polymerization regardless of the production method described above. Examples of monofunctional substances used as molecular weight regulators here include monohydric phenols such as phenol, cresol, p-tert-butylphenol, monohydric acid chlorides such as benzoic acid chloride, methanesulfonyl chloride, and phenyl chloroformate. , Monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, pentanol, hexanol, dodecyl alcohol, stearyl alcohol, benzyl alcohol, phenethyl alcohol, acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid And monovalent carboxylic acids such as acid, toluic acid, phenyl acid, p-tert-butylbenzoic acid, and p-methoxyphenylacetic acid.

  The carboxyl value of the polyarylate of the present invention is preferably 300 μmol / g or less, more preferably 30 μmol / g or less, and particularly preferably 10 μmol / g or less. If the carboxyl value is too high, it may affect electrical properties such as arc discharge resistance and dielectric constant, or may affect the storage stability of polymer solutions prepared by dissolving in a solvent, or a cast film obtained by the solution casting method. May affect the surface properties of the. The carboxyl value of the resin can be measured by a known method such as neutralization titration using a potentiometric titrator.

  The amount of residual alkali metal and halogen in the polyarylate of the present invention is preferably 50 ppm or less, particularly preferably 10 ppm or less. If the residual alkali metal amount and the halogen amount are too high, the above-mentioned electrical characteristics tend to be reduced, and the surface characteristics of the film are also adversely affected, and the performance of the functional film provided with a conductive film, a semiconductor film, etc. Since it may cause a decrease, it is not preferable. The amount of residual alkali metal and halogen in the polyarylate of the present invention can be quantified using known methods such as ion chromatography analysis, atomic absorption spectrometry, and plasma emission spectrometry.

  Further, the amount of the catalyst such as quaternary ammonium salt and quaternary phosphonium salt remaining in the polyarylate of the present invention is preferably less than 200 ppm, more preferably less than 100 ppm. When the amount of the remaining catalyst is too high, the above-mentioned electrical characteristics tend to be lowered, and further, the surface characteristics of the film are adversely affected, and the performance of the functional film provided with a conductive film, a semiconductor film, etc. is deteriorated. There is. Catalysts such as quaternary ammonium salts and quaternary phosphonium salts remaining in the polyarylate of the present invention can be quantified using HPLC, gas chromatography, or the like.

  Furthermore, the amount of the phenol monomer and dicarboxylic acid remaining in the polyarylate of the present invention is preferably 3000 ppm or less, more preferably 500 ppm or less, still more preferably 100 ppm or less. If the amount of residual phenol monomer and carboxylic acid is too high, the above-mentioned electrical characteristics tend to be lowered, and further the surface characteristics of the film are adversely affected, and the performance of the functional film provided with a conductive film, a semiconductor film, etc. May cause decline. For example, when forming a transparent conductive film on a film, due to the influence of heating or plasma during film formation, gas such as residual phenol monomer or carboxylic acid component is generated, or thermal decomposition occurs, A crystal grain lump may be formed in the transparent conductive film, or an uncoated portion called “missing” may be generated, which may adversely affect the lowering of the resistance of the transparent conductive film. The amount of phenol monomer and dicarboxylic acid remaining in the polyarylate and its film can be analyzed by a known method such as HPLC or nuclear magnetic resonance.

The glass transition temperature of the polyarylate of the present invention is preferably 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher.
When the glass transition temperature of the polyarylate of the present invention is 250 ° C. or higher, an inorganic functional layer such as amorphous silicon that requires a high temperature can be installed on the film.
Further, the upper limit of the glass transition temperature of the polyarylate of the present invention is not particularly limited, but when performing a stretching operation, it is difficult if the glass transition temperature is too high, and wet stretching in a form containing a solvent is difficult. Assuming that the glass transition temperature of the polymer is preferably 500 ° C. or lower, more preferably 400 ° C. or lower.

[Optical film]
Next, the optical film of the present invention will be described.
The optical film of the present invention is an optical film comprising the polyarylate of the present invention described above. The “optical film” used in the present invention means a film having a thickness of 10 to 700 μm, a light transmittance at 420 nm of 40% or more, and a total light transmittance of 60% or more.

  As a method for forming the polyarylate of the present invention into a film or sheet shape, a known method can be adopted, and a solution casting method is preferable. Regarding casting and drying methods in the solution casting method, US Pat. No. 2,336,310, US Pat. No. 2,367,603, US Pat. No. 2,492,078, US Patent No. 2,492,977, US Pat. No. 2,492,978, US Pat. No. 2,607,704, US Pat. No. 2,739,069, US Pat. No. 2,739,070, British Patent No. 640731, British Patent No. 736892, Japanese Examined Patent Publication No. 45-4554, Japanese Examined Patent Publication No. 49-5614, Japanese Unexamined Patent Publication No. 60-176634, These are described in JP-A-60-203430 and JP-A-62-115035. As an example of the manufacturing apparatus manufactured by the solution casting method, the manufacturing apparatus described in Japanese Patent Laid-Open No. 2002-189126, paragraphs [0061] to [0068], FIG. 1 and FIG. However, the manufacturing apparatus that can be used in the present invention is not limited to these.

  In the solution casting method, the polyarylate of the present invention is dissolved in a solvent. Any solvent may be used as long as it dissolves the polyarylate of the present invention, but a solvent capable of dissolving the polyarylate of the present invention at a solid content concentration of 10% by mass or more at 25 ° C. is particularly preferable. The solvent used preferably has a boiling point of 200 ° C. or lower, more preferably 150 ° C. or lower. When the boiling point is high, the solvent may be insufficiently dried and may remain in the film. Moreover, it is also possible to mix a poor solvent in the range which does not impair the solubility of the polyarylate of this invention, and in this case, it may become advantageous in terms of stripping after the solution casting and a drying speed.

Solvents that can be used to dissolve the polyarylate of the present invention include, for example, methylene chloride, chloroform, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, benzene, cyclohexane, toluene, xylene, anisole, γ -Butyrolactone, benzyl alcohol, isophorone, cyclohexanone, cyclopentanone, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, ethyl acetate, acetone, chlorobenzene, dichlorobenzene, dimethylformamide, methanol, ethanol, etc. It is done. However, the solvent that can be used in the present invention is not limited thereto.
In addition, two or more of these solvents may be used as a mixture, and a mixed solvent is preferable from the viewpoint of achieving both dryness and solubility. Moreover, by using a mixed solvent, the transparency of the optical film of the present invention may be improved, and it is preferable to use a mixed solvent also from such a viewpoint.

  The concentration of polyarylate in the solution used for solution casting is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, and still more preferably 10 to 30% by mass. If the concentration of polyarylate in the solution is too low, the viscosity is low and it is difficult to adjust the thickness, and if it is too high, the film formability is poor and unevenness increases. Moreover, it becomes possible to reduce the transmittance | permeability of the optical film of this invention, and the impurity in a film by filtering as needed before solution casting.

  The method of casting the solution is not particularly limited, but it can be cast on a flat plate or a roll using a bar coater, a T die, a T die with a bar, a doctor blade, a roll coat, a die coat or the like.

The temperature at which the solvent is dried varies depending on the boiling point of the solvent used, but it is preferable to dry the solvent in two stages. As the first stage, drying is performed at 30 to 100 ° C. until the mass concentration of the solvent is preferably 10% or less, more preferably 5% or less. Next, as a second step, the film is preferably peeled off from the flat plate or roll and dried in a temperature range of 60 ° C. or higher and lower than the glass transition temperature of the resin.
When peeling a film from a flat plate or a roll, it may be peeled off immediately after completion of drying in the first stage, or may be peeled off after being cooled.

  If the optical film of the present invention is insufficiently dried by heating, the amount of residual solvent is large. If it is excessively heated, the polyarylate is thermally decomposed and the amount of residual phenol monomer is increased. Furthermore, rapid drying by heating causes rapid vaporization of the contained solvent, and causes defects such as bubbles in the film. The amount of the solvent remaining in the optical film of the present invention is preferably 2000 ppm or less, more preferably 1000 ppm or less, and particularly preferably 100 ppm or less. If the amount of the remaining solvent is too large, the film surface characteristics may be deteriorated to adversely affect the surface treatment or the like, or the performance of the functional film provided with a conductive film, a semiconductor film or the like may be deteriorated. The amount of the solvent remaining in the polyarylate film of the present invention can be quantified using a known method such as gas chromatography.

  The optical film of the present invention is preferably produced by continuously casting the solution onto a rotating drum or band, stripping off, and drying, and winding it into a roll. As described above, when the optical film of the present invention is mechanically conveyed, it is preferable that the film has high mechanical strength. As a measure of the mechanical strength, the breaking stress and breaking elongation obtained from the tensile test of the film can be used. Although the preferable mechanical strength depends on the conveying device, it cannot be generally specified, but the preferable breaking stress is 50 MPa or more, more preferably 80 MPa or more, and further preferably 100 MPa or more. Although the elongation at break varies depending on the sample preparation conditions and the like, the reliability is low, but is preferably 5% or more, more preferably 10% or more, and further preferably 15% or more.

  The optical film of the present invention may be stretched. The optical film of the present invention has an advantage that the linear thermal expansion coefficient of the film can be further reduced by stretching, and mechanical strength such as folding strength is improved and handling properties are improved. In particular, those having an orientation release stress (ASTMD1504, hereinafter abbreviated as “ORS”) in the stretching direction of 0.3 to 3 GPa are preferable because of their good mechanical strength. ORS is the internal stress caused by stretching that is frozen in a stretched film or sheet.

  For the stretching, a known stretching method can be employed. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284111, JP-A-4-298310, A method described in, for example, Kaihei 11-48271 can be employed. When the polyarylate of the present invention has a glass transition temperature of 300 ° C. or higher, stretching by mere heating is difficult, and stretching in a state containing a solvent is possible. In this case, it is preferable to perform stretching in the course of drying. For example, the roll uniaxial stretching method and the tenter are performed at a temperature between 10 ° C. and 50 ° C. higher than the glass transition temperature (Tg) in the state containing the solvent. The film can be stretched by a uniaxial stretching method, a simultaneous biaxial stretching method, a sequential biaxial stretching method, or an inflation method.

The draw ratio is preferably 1.1 to 5.0 times, more preferably 1.1 to 3.5 times, and particularly preferably 1.1 to 2.0 times in the direction of one axis or two axes. A film having a desired linear thermal expansion coefficient can be obtained by appropriately adjusting the draw ratio. In addition, stretching may be performed in a single stage or in multiple stages. When performing in multiple stages, the product of each draw ratio may be within this range.
The stretching speed is preferably 5% / min to 1000% / min, and more preferably 10% / min to 500% / min.

  Stretching is preferably performed by a heat roll and / or a radiant heat source (such as an IR heater) or warm air. Moreover, you may provide a thermostat in order to improve the uniformity of temperature. When performing uniaxial stretching by roll stretching, it is preferable that L / W which is ratio of the distance (L) between rolls and the film width (W) of this optical film is 2.0-5.0.

  It is preferable to perform a preheating step before stretching. Moreover, you may heat-process after extending | stretching. The heat treatment temperature is preferably 20 ° C. to 10 ° C. higher than the glass transition temperature of the optical film, and the heat treatment time is preferably 1 second to 3 minutes. The heating method may be zone heating or partial heating using an infrared heater.

  The polyarylate of the present invention used for the optical film of the present invention may be composed of only one kind or a mixture of two or more kinds. Moreover, the optical film of the present invention may contain a polymer other than the polyarylate of the present invention as long as the effects of the present invention are not impaired. Moreover, in order to improve solvent resistance, heat resistance, mechanical strength, etc., a crosslinked resin may be added. As the type of the crosslinked resin, various known thermosetting resins and radiation curable resins can be used without particular limitation.

  Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, diallyl phthalate resin, furan resin, bismaleimide resin, cyanate resin and the like. Moreover, even if it is a crosslinking method other than the above, if it is reaction which forms a covalent bond, it can be used without a restriction | limiting especially, At room temperature which forms a urethane bond using a polyalcohol compound and a polyisocyanate compound. A system in which the reaction proceeds can also be used without particular limitation. However, since such a system often has a problem of pot life before film formation, a two-component mixed type in which a polyisocyanate compound is added immediately before film formation is usually used. On the other hand, when it is used as a one-component type, it is effective to protect the functional group involved in the crosslinking reaction, and a block type curing agent or the like can be used. As commercially available block type curing agents, “B-882N” manufactured by Mitsui Takeda Chemical Co., Ltd., “Coronate 2513” manufactured by Nippon Polyurethane Industry Co., Ltd. (above block polyisocyanate), “Cymel 303 manufactured by Mitsui Cytec Co., Ltd.” (Methylated melamine resin) and the like are known. Further, a blocked carboxylic acid such as the following B-1 that protects a polycarboxylic acid that can be used as a curing agent for an epoxy resin is also known.

  The radiation curable resins are roughly classified into radical curable resins and cationic curable resins. As the curable component of the radical curable resin, a compound having a plurality of radical polymerizable groups in the molecule is used. As a typical example, a polyfunctional acrylate monomer having 2 to 6 acrylate groups in the molecule And compounds having a plurality of acrylate groups in the molecule called polyester acrylate and epoxy acrylate. As a typical curing method of the radical curable resin, there are a method of irradiating an electron beam and a method of irradiating ultraviolet rays. Usually, in the method of irradiating with ultraviolet rays, a polymerization initiator that generates radicals upon irradiation with ultraviolet rays is added. In addition, if the polymerization initiator which generate | occur | produces a radical by heating is added, it can also be used as a thermosetting resin. As the curable component of the cationic curable resin, a compound having a plurality of cationic polymerizable groups in the molecule is used. As a typical curing method, a photoacid generator that generates an acid upon irradiation with ultraviolet rays is added, and ultraviolet rays are added. And a method of curing by irradiation. Examples of the cationically polymerizable compound include a compound containing a ring-opening polymerizable group such as an epoxy group and a compound containing a vinyl ether group.

  In the optical film of the present invention, plural types of the thermosetting resin and radiation curable resin mentioned above may be mixed and used, or a thermosetting resin and a radiation curable resin may be used in combination. Moreover, you may mix and use with the polymer which does not have a crosslinkable resin and a crosslinkable group.

  Furthermore, it is also possible to introduce a crosslinkable group into the polyarylate of the present invention used in the optical film of the present invention, and it has a crosslinkable group at any of the polymer main chain terminal, polymer side chain and polymer main chain. It may be. In this case, it can bridge | crosslink without using the general purpose crosslinking | crosslinked resin quoted above together.

  The optical film of the present invention may contain a metal oxide and / or a metal complex oxide and a metal oxide obtained by a sol-gel reaction. By containing these, heat resistance and solvent resistance can be imparted to the optical film of the present invention, as in the case of the crosslinked resin. Furthermore, resin modifiers such as plasticizers, dyes / pigments, antistatic agents, ultraviolet absorbers, antioxidants, inorganic fine particles, peeling accelerators, leveling agents, and lubricants as long as the effects of the present invention are not impaired as necessary. May be added.

  As for the thickness of the optical film of this invention, 30 micrometers-700 micrometers are preferable, More preferably, they are 40 micrometers-200 micrometers, More preferably, they are 50 micrometers-150 micrometers. In any case, the haze value is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less, and the total light transmittance is preferably 70% or more, more preferably 80% or more, and still more preferably 85. % Or more.

  The heat resistant temperature of the optical film of the present invention is preferably high, and the glass transition temperature by DSC measurement can be used as a guide. In this case, the preferable glass transition temperature is 250 ° C. or higher, more preferably 300 ° C. or higher, and particularly preferably 320 ° C. or higher. In addition, when producing the optical film of the present invention by the solution casting method using only the polyarylate of the present invention, if the drying is sufficient, the difference between the Tg of the polyarylate used and the glass transition temperature of the optical film is It is almost within the measurement error range.

  The linear thermal expansion coefficient of the optical film of the present invention is preferably 50 ppm / ° C. or less in the range of 0 to 200 ° C., more preferably −30 to 50 ppm / ° C., and −20 to 45 ppm / ° C. Is more preferable, and it is particularly preferably −10 to 40 ppm / ° C. More preferably, in the range of 0 to 300 ° C., the linear thermal expansion coefficient is preferably 50 ppm / ° C. or less, more preferably −30 to 50 ppm / ° C., and further preferably −20 to 45 ppm / ° C. It is preferably −10 to 40 ppm / ° C.

  On the surface of the optical film of the present invention, other layers are formed depending on the application, or treatment such as saponification, corona treatment, flame treatment, glow discharge treatment, etc. on the film substrate surface in order to enhance the adhesion with the parts. Can be done. Furthermore, an adhesive layer and an anchor layer may be provided on the film surface. Depending on the purpose, smoothing layer for surface smoothing, hard coat layer for imparting scratch resistance, ultraviolet absorbing layer for enhancing light resistance, surface roughening layer for improving film transportability, etc. Various known functional layers can be provided.

  A transparent conductive layer can be installed in the optical film of the present invention. As the transparent conductive layer, a known metal film, metal oxide film, or the like can be applied. Among these, a metal oxide film is preferable from the viewpoint of transparency, conductivity, and mechanical characteristics. For example, as the metal oxide film, indium oxide, cadmium oxide and tin oxide to which tin, tellurium, cadmium, molybdenum, tungsten, fluorine, zinc, germanium, etc. are added as impurities; zinc oxide to which aluminum is added as impurities, oxide Examples thereof include metal oxide films such as titanium. Among them, an indium oxide thin film mainly composed of tin oxide and containing 2 to 15% by mass of zinc oxide is excellent in transparency and conductivity, and is preferably used.

These transparent conductive layers can be formed by any method as long as the target thin film can be formed. For example, the material can be formed from a gas phase such as sputtering, vacuum deposition, ion plating, and plasma CVD. For example, a vapor deposition method in which a film is deposited to form a film is suitable. Can do.
Among these, the sputtering method is preferable from the viewpoint that particularly excellent conductivity and transparency can be obtained.

A preferable degree of vacuum of such a sputtering method, a vacuum deposition method, an ion plating method, and a plasma CVD method is 0.133 mPa to 6.65 Pa, more preferably 0.665 mPa to 1.33 Pa. Before providing such a transparent conductive layer, it is preferable to subject the base film to a surface treatment such as plasma treatment (reverse sputtering) or corona treatment. Moreover, you may heat up to 50 to 200 degreeC during providing the transparent conductive layer.
The thickness of the transparent conductive layer thus obtained is preferably 20 nm to 500 nm, more preferably 50 nm to 300 nm.
Further, the surface electrical resistance measured at 25 ° C. and 60% relative humidity of the transparent conductive layer thus obtained is preferably 0.1Ω / □ to 200Ω / □, more preferably 0.1Ω / □ to 100Ω. / □, more preferably 0.5Ω / □ to 60Ω / □. Further, the light transmittance is 80% or more, more preferably 83% or more, and still more preferably 85% or more.

  The optical film of the present invention is preferably provided with a gas barrier layer in order to suppress gas permeability. Preferred gas barrier layers include, for example, metal oxides composed mainly of one or more metals selected from the group consisting of silicon, aluminum, magnesium, zinc, zirconium, titanium, yttrium, and tantalum, silicon, aluminum, boron And a layer made of a metal nitride or a mixture thereof. Among these, the main component is silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 in terms of gas barrier properties, transparency, surface smoothness, flexibility, film stress, cost, and the like. Metal oxide is good. These inorganic gas barrier layers can be produced by vapor deposition such as sputtering, vacuum deposition, ion plating, plasma CVD, or the like, in which a material is deposited in the vapor phase to form a film. Of these, the sputtering method is preferred from the viewpoint that particularly excellent gas barrier properties can be obtained. Further, the temperature may be raised to 50 ° C. to 200 ° C. while the gas barrier layer is provided.

The film thickness of the gas barrier layer thus obtained is preferably 10 nm to 300 nm, more preferably 30 nm to 200 nm.
Such a gas barrier layer may be provided on the same side as the transparent conductive layer or on the opposite side, but it is more preferable to provide it on the opposite side of the side on which the transparent conductive layer is provided.
The barrier property of the film having the gas barrier layer thus obtained (gas barrier film) is preferably 5 g / m ² · day or less, more preferably 1 g / m ² , measured at 40 ° C. and 90% relative humidity. m ² · day or less, more preferably 0.5 g / m ² · day or less. The oxygen permeability measured at 40 ° C. and 90% relative humidity is preferably 1 ml / m ² · day or less, more preferably 0.7 ml / m ² · day or less, and even more preferably 0.5 ml / m ² · day. It is as follows.

In the optical film of the present invention, it is particularly desirable to provide a defect compensation layer adjacent to the gas barrier layer for the purpose of improving the barrier property. As the defect compensation layer, (1) a method using an inorganic oxide layer produced using a sol-gel method as described in US Pat. No. 6,171,663 and JP-A-2003-94572, 2) A method using an organic material layer as described in US Pat. No. 6,413,645, a method of depositing under vacuum and then curing with ultraviolet rays or an electron beam, or a method of heating, applying electrons after coating. It can be produced by a method of curing with a wire, ultraviolet ray or the like.
When the defect compensation layer is produced by a coating method, various conventionally used coating methods such as spray coating, spin coating, and bar coating can be used.

  The optical film of the present invention can be applied to various uses that can utilize the optical characteristics thereof. In particular, the present invention can be preferably applied to an image display device as described below. The optical film of the present invention can also be used for applications such as solar cells and touch panels. The touch panel can be applied to those described in JP-A-5-127822, JP-A-2002-48913, and the like.

[Image display device]
In particular, the optical film of the present invention can be used in an image display device after providing various functional layers as necessary. Here, it does not specifically limit as an image display apparatus, A conventionally well-known thing can be used. Moreover, the flat panel display excellent in display quality can be produced using the optical film of this invention. Flat panel displays include liquid crystals, plasma displays, electroluminescence (EL), fluorescent display tubes, light emitting diodes, etc. In addition to these, they should be used as substrates instead of display-type glass substrates that have conventionally used glass substrates. Can do.

  The optical film of the present invention can be used as a substrate for a thin film transistor (TFT) display element. Examples of the method for producing the TFT array include the method described in JP-T-10-512104. Further, these substrates may have a color filter for color display. The color filter may be produced using any method, but a photolithography technique is preferable.

When the optical film of the present invention is used for a liquid crystal display or the like, the film is preferably made of an amorphous polymer in order to achieve optical uniformity. In addition, when used for such applications, it is preferable that the birefringence of the optical film of the present invention is small, in particular, the in-plane retardation (Re) is preferably 50 nm or less, more preferably 30 nm or less, even more preferably. Is 15 nm or less. In order to obtain an optical film having a small birefringence by using only the polyarylate of the present invention, it is possible to appropriately adjust the solvent and drying conditions during solution casting. Moreover, it can also extend | stretch and adjust as needed. Further, for the purpose of controlling retardation (Re) and its wavelength dispersion, resins having different intrinsic birefringence signs can be combined, or resins having a large (or small) wavelength dispersion can be combined. In addition, the optical film of the present invention can be suitably used for the purpose of controlling retardation (Re) and improving gas permeability and mechanical properties, etc. Further, phase difference compensation can be performed by using a known retardation plate in combination.
In addition, Re mentioned here is 25 ° C./relative humidity using an automatic birefringence meter (KOBRA-21ADH: manufactured by Oji Scientific Instruments) after conditioning the film for 24 hours at 25 ° C./60% relative humidity. It is a value measured at 60%. Re is measured by making light of wavelength λnm (normally λ = 590 ± 5 nm) incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments).

A reflective liquid crystal display device is generally composed of a lower substrate, a reflective electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, a transparent electrode, an upper substrate, a λ / 4 plate, and a polarizing film in order from the bottom. . Of these, the optical film of the present invention may be used as a λ / 4 plate or a protective film for a polarizing film by adjusting optical properties, but is preferably used as a substrate (upper and lower substrates) from the viewpoint of heat resistance. It is also preferable to use it as a transparent electrode and an upper substrate with an alignment film from the viewpoint of transparency. Moreover, a gas barrier layer, TFT, etc. can also be provided as needed. In the case of color display, it is preferable to further provide a color filter layer between the reflective electrode and the lower alignment film, or between the upper alignment film and the transparent electrode.
The transmissive liquid crystal display device includes, in order from the bottom, a backlight, a polarizing plate, a λ / 4 plate, a lower transparent electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, an upper transparent electrode, an upper substrate, a λ / 4 plate, and Generally, it is made of a polarizing film. Of these, the optical film of the present invention may be used as a λ / 4 plate or a protective film for a polarizing film by adjusting optical properties, but is preferably used as a substrate (upper and lower substrates) from the viewpoint of heat resistance, and transparent electrodes It is preferable to use it as a substrate with an alignment film. Moreover, a gas barrier layer, TFT, etc. can also be provided as needed. In the case of color display, it is preferable to further provide a color filter layer between the lower transparent electrode and the lower alignment film, or between the upper alignment film and the transparent electrode.

  As the types of liquid crystal layers (liquid crystal cells), TN (Twisted Nematic), IPS (In-P1ane Switching), FLC (Ferroelectric Liquid Crysta1), AFLC (Anti-ferroelectric Liquid Crystal), OCB (Optica1ly Compensatory Bend), STN (Supper Various display modes such as Twisted Nematic (VA), VA (Vertically Aligned), and HAN (Hybrid Aligned Nematic) have been proposed. There has also been proposed a display mode in which the display mode is orientation-divided. The optical film of the present invention can be effectively used in a liquid crystal display device in any display mode. In addition, the liquid crystal display device can be effectively used in any of transmissive, reflective, and transflective liquid crystal display devices.

  These liquid crystal display devices are disclosed in JP-A-2-176625, JP-B-7-69536, MVA (SID97, Digest of tech. Papers (Preliminary Proceedings) 28 (1997) 845), SID99, Digest of tech. Papers (Proceedings) 30 (1999) 206, JP-A-11-258605, SURVAIVAL (Monthly Display, Vol. 6, No. 3 (1999) 14), PVA (Asia Display 98, Proc. Of the-18th- Inter. Display res. Conf. (Proceedings) (1998) 383), Para-A (LCD / PDP International 99), DDVA (SID98, Digest of tech. Papers 29 (1998) 838), EOC. (SID98, Digest of tech. Papers (Preliminary Proceedings) 29 (1998) 319), PSHA (SID98, Digest of tech. Papers (Preliminary Proceeds) 29 (1998) 108 ), RFFMH (Asia Display 98, Proc. Of the-18th-Inter. Display res. Conf. (Preliminary Proceedings) (1998) 375), HMD (SID98, Digest of tech. Papers 70 (Proceedings) 70 (19) ), JP-A-10-123478, International Publication No. W098 / 48320, Japanese Patent No. 3022477, International Publication No. 00/65384, and the like.

As described above, the optical film of the present invention is provided with a gas barrier layer and a TFT as necessary, and can be used as a substrate with a transparent electrode for organic EL display applications.
As a specific layer structure as the organic EL display element, anode / light emitting layer / transparent cathode, anode / light emitting layer / electron transport layer / transparent cathode, anode / hole transport layer / light emitting layer / electron transport layer / transparent cathode , Anode / hole transport layer / light emitting layer / transparent cathode, anode / light emitting layer / electron transport layer / electron injection layer / transparent cathode, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron Examples include injection layer / transparent cathode.

The organic EL element that can use the optical film of the present invention can emit light by applying a DC voltage or a DC current between the anode and the cathode. The DC voltage is usually 2 to 40 volts, and may include an AC component as necessary.
Regarding the driving of these light emitting elements, JP-A-2-148687, JP-A-6-301355, JP-A-5-290080, JP-A-7-134558, JP-A-8-234485, JP-A-8-214447, etc., US The methods described in Japanese Patent Nos. 5,828,429 and 6,023,308, and Japanese Patent No. 2784615 can be used.

  The features of the present invention will be described more specifically with reference to synthesis examples and examples. The following materials, amounts used, ratios, processing details, processing procedures, and the like can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Synthesis Example 1]
(Synthesis of Exemplified Compound P-1)
In a 500 ml three-necked flask equipped with a stirrer and a reflux condenser, 8.13 g of bisphenolfluorene, 4.58 g of (R)-(+)-1,1′-bi-2-naphthol, sodium hydrosulfite 120 mg, tetrabutylammonium chloride 556 mg, dichloromethane 130 ml and water 150 ml were added, and the mixture was stirred at 300 rpm in a water bath under a nitrogen stream.

After 15 minutes, a solution prepared by dissolving 4.06 g of terephthalic acid chloride in 60 ml of dichloromethane was added.
Further, while stirring the above solution, 42 ml of a 2 mol / L sodium hydroxide aqueous solution, 240 mg of 4-tert-butylphenol and 18 ml of water were added dropwise over 1 hour under a nitrogen stream. Thereafter, stirring was continued for 3 hours, and then 1.5 L of dichloromethane, 99.4 ml of 0.1 mol / L hydrochloric acid aqueous solution and 500 ml of water were added, and the organic layer was separated. The obtained organic layer was put into 1 L of methanol. The precipitated white precipitate was collected by filtration, washed with 1 L of methanol, then heated and dried at 40 ° C. for 12 hours, and then dried at 70 ° C. for 3 hours under reduced pressure to obtain 16.38 g of Exemplified Compound P-1.

  As a result of measuring the molecular weight of P-1 obtained by GPC (tetrahydrofuran solvent; polystyrene conversion (manufactured by Tosoh Corporation, HLC-8120GPC)), the weight average molecular weight was 55,000. The glass transition temperature was 331 ° C., and the 5% mass reduction temperature was 483 ° C.

  Other polyarylate of the present invention can also be synthesized by the same method as in Synthesis Example 1.

[Comparative Synthesis Example 1]
(Synthesis of comparative polymer (BPFL-I / T))
Polyarylate derived from fluorene bisphenol-isophthalic acid / terephthalic acid (hereinafter also referred to as BPFL-I / T) was synthesized by the following procedure.

25.3 g of BPFL (trade name; manufactured by JFE Chemical Co., Ltd.), 9.17 g of tetrabutylammonium chloride, 222 ml of dichloromethane, 69.3 ml of 2 mol / L sodium hydroxide aqueous solution, 38 ml of water, reaction vessel equipped with a stirrer The mixture was put into the inside and stirred at 300 rpm in a water bath under a nitrogen stream. After 30 minutes, a solution of 6.7 g of isophthalic acid chloride and 6.7 g of terephthalic acid chloride in 74 ml of dichloromethane was added. Thereafter, stirring was continued for 3 hours, and then 100 mL of dichloromethane was added to separate the organic phase. Further, a solution obtained by diluting 0.66 ml of 12 mol / L hydrochloric acid water with 250 ml of water was added to wash the organic layer. After further washing with 250 ml of water twice, 100 ml of dichloromethane was added to the separated organic layer, diluted, and then poured into 2.5 liters of vigorously stirred methanol over 1 hour. The resulting white precipitate in methanol was collected by filtration, heated and dried at 40 ° C. for 12 hours, and then dried at 70 ° C. for 3 hours under reduced pressure to obtain 28 g of a comparative polymer BPFL-I / T.
As a result of measuring the molecular weight of the obtained BPFL-I / T by GPC (THF solvent), the weight average molecular weight was 50,000. The glass transition temperature measured by DSC was 320 ° C.

[Comparative Synthesis Example 2]
(Synthesis of comparative polymer (PEsI-R))
Polyesterimide derived from (R) -BNDEDA-phenylenediamine (hereinafter also referred to as PEsI-R) was prepared by the following procedure described in J. Polym. Sci., Part A; Polym. Chem. 42, 4318 (2004). Synthesized.

Synthesis of (R) -BNDEDA 32.4 g of trimellitic anhydride, 12.4 mL of pyridine, and 100 ml of toluene were added to a 500 ml three-necked flask equipped with a stirrer and a reflux dehydrator, and stirred at room temperature. After dissolution, a solution in which 20.0 g of R)-(+)-1,1′-B-2-naphthol was dissolved in 100 mL of toluene was dropped over 1 hour, gradually heated, and stirred at 80 ° C. for 4 hours. did.
After completion of the reaction, 300 mL of hexane was added, and the resulting precipitate was washed with water and then recrystallized with acetic anhydride / acetic acid to obtain 24.0 g of (R) -BNDEDA. The product was identified by 400 MHz ¹ HNMR.

¹ HNMR (d ₆ -DMSO), δ (ppm): 8.31 ppm (d, 2H), 8.22-8.20 ppm (m, 6H), 7.98 ppm (d, 2H), 7.86 ppm (d , 2H), 7.70 ppm (m, 2H), 7.58 ppm (m, 2H), 7.36 ppm (d, 2H)

In a reaction vessel equipped with a stirrer, 350 mg of phenylenediamine and 30 mL of DMAc were added. After dissolution, 2.05 g of (R) -BNDEDA was added, and the mixture was stirred at room temperature for 6 hours under a nitrogen stream. Thereafter, 1 mL of acetic anhydride and 0.5 mL of triethylamine were added, and stirring was continued at room temperature for 12 hours, followed by gradually heating and stirring at 80 ° C. for 1 hour. After cooling, 200 mL of ethanol was added to precipitate the polymer. The obtained precipitate was collected by filtration in ethanol, heat-dried at 40 ° C. for 12 hours, and then dried at 180 ° C. for 24 hours under reduced pressure to obtain 2.33 g of a comparative polymer PEsI-R.
As a result of measuring the molecular weight of the obtained PEsI-R with GPC (DMF solvent), the weight average molecular weight was 62,000. The glass transition temperature measured by DSC was 290 ° C.

[Example 1]
(Production and evaluation of optical film sample)
The solution viscosity after dissolving BPFL and polyarylate (BPFL-I / T) derived from isophthalic acid / terephthalic acid (equal mole) as a comparative polymer in the present invention in dichloromethane is 500 to 1500 mPa · s. Dissolved at a concentration in the range. The solution was filtered through a 5 μm filter and cast on a glass substrate using a doctor blade. After casting, the film was heat-dried at room temperature for 20 minutes, 35 ° C. for 10 minutes, and 200 ° C. for 2 hours, and then the film was peeled off from the glass substrate to prepare optical film samples (samples 101 to 104 and 109). Further, the comparative polymer PEsI-R was dissolved at a concentration such that the solution viscosity after dissolution in DMAc was in the range of 500 to 1500 mPa · s. The solution was filtered through a 5 μm filter and cast on a glass substrate using a doctor blade. After casting, the film was heated and dried at room temperature for 20 minutes, 140 ° C. for 60 minutes, and 200 ° C. for 2 hours, and then the film was peeled off from the glass substrate to prepare an optical film sample (sample 111).
Furthermore, after casting the glass plate, the obtained optical film sample was peeled off in an insufficiently dried state (containing about 20% by mass of solvent), one side of the obtained film was fixed, and a longitudinal uniaxial at a temperature of 100 ° C. The film was stretched 1.1 to 1.3 times with tension in the direction, and then the tension was removed and heat treatment was performed at 200 ° C. for 1 hour to prepare optical film samples (samples 105 to 108, 110 and 112).

<Evaluation>
The linear thermal expansion coefficient, total light transmittance, and film thickness of the obtained optical film sample were measured by the following methods. Moreover, the weight average molecular weight and glass transition temperature (Tg) of the used polymer were measured with the following method. The results are shown in Table 1.

<Linear thermal expansion coefficient>
Measurement was performed with TMA8310 (manufactured by Rigaku Denki Co., Thermo Plus series), and an average value of 0 to 200 ° C. was calculated.

<Total light transmittance of film>
Suga Test Co., Ltd. product haze meter: Measured with model number HGM-2DP.

<Film thickness>
It was measured with a dial-type thickness gauge (manufactured by Anritsu Co., Ltd., K402B).

<Weight average molecular weight>
By GPC measurement using polystyrene as a solvent using tetrahydrofuran as a solvent, GPC (manufactured by Tosoh Corporation, HLC-8120GPC) was used for comparison with a molecular weight standard product of polystyrene.

<Glass transition temperature (Tg)>
Using a differential scanning calorimeter (Seiko Co., Ltd., DSC6200), Tg of each optical film sample was measured in nitrogen at a temperature rising temperature of 10 ° C./min.

  From Table 1, it can be seen that the sample of the present invention has a higher Tg than the sample of the comparative example, and the sample of the present invention has a lower linear thermal expansion coefficient than the sample of the comparative example. It was revealed. Furthermore, it was also revealed that the sample of the present invention has higher total light transmittance than PEsI-R described in J. Polym. Sci., Part A; Polym. Chem. 42, 4318 (2004). It has also been clarified that the sample of the present invention can greatly reduce the linear thermal expansion coefficient while being stretched while maintaining a high total light transmittance and a high Tg. Furthermore, it can be seen from the above data that a highly transparent film having a desired Tg and a desired linear thermal expansion coefficient can be obtained by appropriately selecting the kind of polyarylate of the present invention and the draw ratio.

[Example 2]
(Preparation of organic EL element sample)
<Installation of gas barrier layer>
On both surfaces of the optical film samples 101 to 112 produced as described above, oxygen was introduced in an Ar atmosphere under a vacuum of 500 Pa, using Si as a target, and sputtered at an output of 5 kW under a pressure of 0.1 Pa. The film thickness of the obtained gas barrier layer was 60 nm. The optical film sample on which the gas barrier layer is formed has a water vapor permeability of 0.1 g / m ² · day or less at 40 ° C. and a relative humidity of 90%, and an oxygen permeability of 0.1 ml / m at 40 ° C. and a relative humidity of 90%. ² · day or less.

<Installation of transparent conductive layer>
While heating the optical film sample provided with the gas barrier layer to 100 ° C, ITO (In ₂ O ₃ 95% by mass, Sn0 ₂ 5% by mass) was used as a target by DC magnetron sputtering under a vacuum of 0.665 Pa, Ar A transparent conductive layer made of an ITO film having an output of 5 kW and a thickness of 140 nm was provided on one side in an atmosphere. The surface electrical resistance at 25 ° C. and 60% relative humidity of the optical film sample provided with the transparent conductive layer was 30Ω / □.

<Heat treatment of optical film with transparent conductive layer>
The optical film sample provided with the transparent conductive layer obtained above was subjected to heat treatment at 300 ° C. for 1 hour assuming TFT installation.

<Production of organic EL element>
The aluminum lead wire was connected from the transparent electrode layer of the optical film sample provided with the transparent conductive layer subjected to the heat treatment as described above to form a laminated structure. In addition, since the optical film sample which installed the transparent conductive layer obtained from the samples 109-112 of the comparative example deform | transformed severely, preparation of an organic EL element was not performed. The organic EL element was produced about the optical film sample which installed the transparent conductive layer obtained from the samples 101-108 of this invention.
The surface of the transparent conductive layer (electrode) was spin-coated with an aqueous dispersion of polyethylene dioxythiophene / polystyrenesulfonic acid (BAYER, Baytron P: solid content: 1.3% by mass), and then vacuumed at 150 ° C. for 2 hours. It dried and formed the hole transportable organic thin film layer of thickness 100nm. This was designated as substrate X.
On the other hand, using a spin coater, a coating solution for a light-emitting organic thin film layer having the following composition was formed on one side of a temporary support made of polyethersulfone having a thickness of 188 μm (Sumilite FS-1300, manufactured by Sumitomo Bakelite Co., Ltd.). By coating and drying at room temperature, a light-emitting organic thin film layer having a thickness of 13 nm was formed on the temporary support. This was designated as transfer material Y.

〔composition〕
Polyvinylcarbazole (Mw = 63000, manufactured by Aldrich): 40 parts by mass Tris (2-phenylpyridine) iridium complex (orthometalated complex): 1 part by mass Dichloroethane: 3200 parts by mass

  The luminescent organic thin film layer side of the transfer material Y is superimposed on the upper surface of the organic thin film layer of the substrate X, heated and pressurized at 160 ° C., 0.3 MPa, 0.05 m / min using a pair of heat rollers, and the temporary support is attached. By peeling off, a light-emitting organic thin film layer was formed on the upper surface of the substrate X. This was designated as substrate XY.

In addition, a patterned evaporation mask (a mask with a light emitting area of 5 mm × 5 mm) is installed on one side of a polyimide film having a thickness of 50 μm cut into 25 mm square (manufactured by Ube Industries, UPILEX-50S), Al was evaporated in a reduced pressure atmosphere of about 0.1 mPa to form an electrode having a thickness of 0.3 μm. Using an Al ₂ O ₃ target by DC magnetron sputtering, the Al ₂ O ₃ was deposited in the same pattern as the Al layer and the thickness of 3 nm. An aluminum lead wire was connected from the Al electrode to form a laminated structure. A coating solution for an electron transporting organic thin film layer having the following composition is coated on the obtained laminated structure using a spin coater coating machine, and vacuum dried at 80 ° C. for 2 hours, thereby transporting an electron having a thickness of 15 nm. An organic thin film layer was formed. This was designated as substrate Z.

〔composition〕
Polyvinyl butyral 2000L (Mw = 2000, manufactured by Denki Kagaku Kogyo):
10 parts by mass 1-butanol: 3500 parts by mass Electron transporting compound having the following structure: 20 parts by mass

  Using substrate XY and substrate Z, the electrodes are stacked so that the electrodes face each other with the light-emitting organic thin film layer sandwiched between them, and heated and pressed at 160 ° C., 0.3 MPa, 0.05 m / min using a pair of heat rollers. Corresponding organic EL element samples 201 to 208 were obtained from the optical films 101 to 108, respectively.

  A direct voltage was applied to the organic EL elements of the obtained organic EL element samples 201 to 208 using a source measure unit 2400 type (manufactured by Toyo Technica Co., Ltd.). It was confirmed that Samples 201 to 208 of the present invention emitted light.

  From the said Example, it became clear that the optical film of this invention has a high glass transition temperature and a low linear thermal expansion coefficient, and is excellent also in transparency. Further, it has been clarified that a gas barrier layer and a transparent conductive layer can be laminated and function as a substrate film for an organic EL element even if a heat treatment assuming a TFT process is performed.

  The polyarylate and optical film of the present invention have a high glass transition temperature and a low linear thermal expansion coefficient, and are excellent in transparency. In addition, the polyarylate of the present invention is useful as an optical film because it has excellent mechanical properties that allow film formation. It is particularly suitable for various functional layer installation processes such as TFT installation processes that require high-temperature processes, and is suitable as a substrate for plastic displays such as organic EL. Therefore, the present invention has high industrial applicability.

Claims (13)

A polyarylate having at least one of the structures represented by the following general formula (1) or (2) in the main chain and an optically active site.

[In general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings α may be the same or different. The two rings α are connected by a spiro bond. ]

[In general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Two rings γ are linked to one quaternary carbon on ring β. ]   The polyarylate according to claim 1, wherein the optically active site has axial chirality. The polyarylate according to claim 1 or 2, wherein the optically active site having axial chirality has a structure represented by the following general formula (3).

[In general formula (3), ring δ represents a monocyclic or polycyclic ring, and the two rings δ may be the same or different. The two rings δ are directly connected by a single bond. ] The polyarylate according to claim 3, wherein the positions at which the two rings δ in the general formula (3) are each bonded to the main chain are α-position or β-position of the carbon atom forming the single bond. . The polyarylate according to claim 1 or 2, wherein the optically active site having axial chirality has a structure represented by the following general formula (8).

[In General Formula (8), R ⁵¹ and R ⁵² each independently represents a substituent. When there are a plurality of substituents represented by R ⁵¹ and R ⁵² , each substituent may be the same or different, and each may be linked to form a ring. m and n each independently represents an integer of 0 to 6. ]   The polyarylate according to any one of claims 1 to 5, wherein the glass transition temperature is 250 ° C or higher.   An optical film comprising the polyarylate according to any one of claims 1 to 6.   8. The optical film according to claim 7, wherein the optical film is obtained by stretching at a draw ratio of 1.1 to 5.0 times in a uniaxial or biaxial direction.   The optical film according to claim 7 or 8, wherein a linear thermal expansion coefficient at 0 to 200 ° C is 50 ppm / ° C or less.   The optical film according to any one of claims 7 to 9, wherein the total light transmittance is 80% or more.   It has a gas barrier layer on the optical film of any one of Claims 7-10, The optical film characterized by the above-mentioned.   It has a transparent conductive layer on the optical film of any one of Claims 7-11, The optical film characterized by the above-mentioned.   An image display device comprising the optical film according to claim 7.