JP4991479B2 - Optical film and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film comprising a polyester resin having high refractive index, low birefringence and easy moldability, and in particular, the optical film retaining the low birefringence after stretch forming, and to provide its manufacturing method. <P>SOLUTION: This optical film is composed of the polyester resin prepared by polymerizing a diol component having at least a 9,9-bis(hydroxy aryl)fluorene backbone having a repeating unit represented by formula (1) (wherein A is an aliphatic hydrocarbon residue, Z<SP>1</SP>and Z<SP>2</SP>are an aromatic hydrocarbon residue, R<SP>4</SP>is a halogen atom, etc., R<SP>1a</SP>and R<SP>1b</SP>are an alkylene group, R<SP>2a</SP>, R<SP>2b</SP>, R<SP>3a</SP>and R<SP>3b</SP>are an alkyl group, etc, m and n are an integer of 0 or &ge;1, h1 and h2 are an integer of 0 to 6, j1 and j2 are an integer of 0 to 4, and k is an integer of &ge;0) with a dicarboxylic acid component. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an optical film containing a polyester resin having a fluorene skeleton and having a small birefringence, particularly an optical film having a low birefringence even after stretch molding, and a method for producing the same.

  Flat panel displays (FPDs) such as liquid crystal displays (LCDs) and plasma displays (PDPs) are indispensable as video and display devices in the recent information technology (Information Technology, IT) era. Personal computers, televisions, mobile phones Used for telephones. An optical film is one of representative members among the optical members constituting the FPD. In addition, since the performance of optical films greatly affects the accuracy of optical devices, the optical film has a high refractive index, low birefringence, Easy moldability is further required. As such an optical film, a retardation film, a polarizing film, a near-infrared shielding film and the like are known, and polymers such as polymethyl methacrylate (PMMA), polycarbonate (PC), and cycloolefin polymer (COP) have been conventionally used. ing.

  PMMA is excellent in transparency and low birefringence, but because of its high hygroscopicity, the form stability after molding is inferior and physical properties may change. Furthermore, since PMMA has a lower refractive index than other optical polymers, it is difficult to reduce the thickness and size of the film.

  PC is often used as an optical material because it is excellent in transparency, heat resistance and hygroscopicity and exhibits a high refractive index. However, since PC is inferior in moldability and has a high birefringence, when light is incident on an optical film made of PC, an extraordinary ray is generated together with an ordinary ray, and it is difficult to view an object as a single object. Therefore, PC is not always satisfactory as a raw material for optical films.

  Further, COP has excellent heat resistance and low hygroscopicity although it does not reach PMMA in terms of transparency and low birefringence. However, COP has excellent heat resistance and low hygroscopicity, but its refractive index is about 1.51 to 1.54, and birefringence does not reach PMMA, and birefringence appears when stretched. To do. In addition, when a soft component such as ethylene is used as a copolymerization component in order to improve the fluidity of the COP resin, there is a drawback that the physical properties of the resin change (for example, the refractive index decreases).

  In film formation, a stretching operation is performed in order to significantly improve physical properties such as mechanical strength, transparency, and heat resistance. However, a stretched film generally has a higher birefringence due to the effects of stress strain and molecular orientation than an unstretched film, so it is difficult to obtain a high-performance optical stretched film.

  As a stretched film having the above characteristics, a stretched film using an aromatic polycarbonate resin having a fluorene skeleton has been proposed. For example, in Japanese Patent No. 34993838 (Patent Document 1), a retardation film obtained by uniaxially stretching an aromatic polycarbonate film having a fluorene skeleton is disclosed in Japanese Patent Application Laid-Open No. 2001-146527 (Patent Document 2). An LCD film in which a polycarbonate film is uniaxially stretched by 100% is disclosed in Japanese Patent Application Laid-Open No. 7-52270 (Patent Document 3), such as an optical film in which the aromatic polycarbonate film is uniaxially stretched by 9 to 13%. These stretched films reduce the high birefringence, which is an inherent disadvantage of polycarbonate films, and further suppress the increase in the birefringence of the film due to the stretching process. Compared to conventional polycarbonate films, these films have a higher refractive index and birefringence. The optical properties such as are improved. However, the fluidity is low, and there may be a problem in moldability and stretching.

In addition, polyester resins having a fluorene skeleton have been proposed as transparent resins having a high refractive index and low birefringence. Since these resins have fluidity and excellent moldability, they are processed and widely used as various optical members. For example, in Japanese Patent Application Laid-Open No. 2004-315676 (Patent Document 4), a polyester resin having a fluorene skeleton is used as an optical lens, and in Japanese Patent Application Laid-Open No. 7-198901 (Patent Document 5), a plastic lens is used. No. (Patent Document 6) is used for an optical disk substrate lens, and Japanese Patent Application Laid-Open No. 8-160222 (Patent Document 7) is used for an optical compensation film substrate. As described above, the polyester resin has been subjected to various molding processes. However, since the birefringence is generally increased by stretching as described above, the stretched molded article is not suitable for use as an optical member. For this reason, it is considered that it is difficult to obtain a polyester film having a low birefringence even when subjected to stretch molding, and a polyester resin having a fluorene skeleton (especially a 9,9-bis (hydroxyaryl) fluorene skeleton). A stretched film having a low birefringence index including a polyester resin having a high molecular weight has not been reported so far.
Japanese Patent No. 3499838 (paragraph numbers [0005 to 0007]) JP 2001-146527 A (Examples 1 to 3) JP-A-7-52270 (Examples 1 to 12) JP 2004-315676 A (paragraph number [0011]) Japanese Patent Application Laid-Open No. 7-198901 (Claims 1) JP 9-302077 A (Claim 6) JP-A-8-160222 (paragraph number [0016])

  Accordingly, an object of the present invention is to provide an optical film composed of a polyester resin and having a high refractive index and low birefringence, and a method for producing the same.

  Another object of the present invention is to provide an optical film capable of maintaining low birefringence after stretch molding and a method for producing the same.

  Still another object of the present invention is to provide a high-function (or high-performance) optical film that has easy moldability and is useful as a film component for optical equipment, and a method for producing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention provided a film containing a specific polyester resin produced by esterification of an aromatic diol having a specific fluorene skeleton and a dicarboxylic acid. However, the present inventors have found that an optical film having a high refractive index, low birefringence and easy moldability can be obtained without impairing the inherent properties of the polyester resin.

  That is, the optical film (polyester film) of the present invention is a polyester resin obtained from a diol component composed of a diol having at least a 9,9-bis (hydroxyaryl) fluorene skeleton and a dicarboxylic acid component (in detail, A polyester resin in which a diol component and a dicarboxylic acid component are polymerized). In such an optical film, the polyester resin may be a homopolyester formed of a single diol component and a dicarboxylic acid component, or may be a copolyester obtained by copolymerizing copolymer components. For example, the diol component may be composed of a diol having a 9,9-bis (hydroxyaryl) fluorene skeleton and an alkylene glycol. Such a polyester resin has, for example, at least a repeating unit represented by the following formula (1).

[Wherein, A represents an aliphatic hydrocarbon residue, an alicyclic hydrocarbon residue or an aromatic hydrocarbon residue, and Z ¹ and Z ² are the same or different and represent an aromatic hydrocarbon residue. R ⁴ represents a halogen atom or an alkyl group, R ^1a and R ^1b are the same or different and each represents an alkylene group, R ^2a , R ^2b , R ^3a and R ^3b are the same or different and represent an alkyl group, an alkoxy group, An aryl group, a cycloalkyl group, an aralkyl group, a nitro group or a cyano group is shown, and m and n are the same or different and are 0 or an integer of 1 or more. h1 and h2 are the same or different and are an integer of 0 to 6, j1 and j2 are the same or different and are an integer of 0 to 4, and k is an integer of 0 or more.
The polyester resin may be a homopolyester or a copolyester. Such a resin may have, for example, at least a repeating unit represented by the formula (1) and a repeating unit represented by the following formula (2).

[Wherein, A, R ⁴ and k are the same as above. R ^1c represents an alkylene group, and q is an integer of 1 or more.
The ratio between the unit represented by the formula (1) and the unit represented by the formula (2), the former / the latter (molar ratio) may be 99/1 to 10/90.

In the formulas (1) and (2), A represents a C _1-10 aliphatic hydrocarbon residue, a C _5-10 cycloalkane residue, or a C _6-14 aromatic hydrocarbon residue (for example, a phenylene group). Yes, R ⁴ may be a halogen atom. k may be an integer of about 0 to 8 (for example, 0 to 2). In the formula (1), Z ¹ and Z ² may be a C _6-14 aromatic hydrocarbon residue (for example, a phenylene group or a naphthylene group), and R ^1a and R ^1b are C _2-4. An alkylene group (for example, ethylene group) may be sufficient and _C2-5 alkyl group (for example, methyl group) may be sufficient as R ^{< 2a>} , R ^<2b> , R ^<3a> and R ^<3b _> . The coefficients m and n may be integers of about 1 to 10 (for example, 1 to 5), h1 and h2 may be integers of about 0 to 3 (for example, 0 to 2), and j1 and j2 are It may be an integer of about 0 to 2 (for example, 0 or 1). In the formula (2), R ^1c may be a C _2-10 alkylene group (for example, a C _2-4 alkylene group), and q is an integer of about 1 to 5 (for example, 1 to 3). There may be. The ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is the former / the latter (molar ratio) = 99/1 to 50/50 (for example, 99/1 to 75/25). ) Degree.

  Representative optical films of the present invention include the following optical films (i) to (iii).

(I) In the formula (1) and the formula (2), A is a C _1-10 aliphatic hydrocarbon residue, a C _5-10 cycloalkane residue or a C _6-14 aromatic hydrocarbon residue, Z ¹ and Z ² are C _6-14 aromatic hydrocarbon residues, R ^1a and R ^1b are C _2-4 alkylene groups, R ^1c is a C _2-10 alkylene group, R ^2a , R ^{2 2b} , R ^3a and R ^3b are C _1-5 alkyl groups, m and n are integers of 1 to 10, h1 and h2 are integers of 0 to 3, and j1 and j2 are integers of 0 to 2. K is an integer of 0 to 8, q is an integer of 1 to 5, and the ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is the former. / The latter (molar ratio) = 99/1 to 60/40 optical film.

(Ii) A is a C _5-10 cycloalkane residue or C _6-10 aromatic hydrocarbon residue, Z ¹ and Z ² are a phenylene group or a naphthylene group, R ⁴ is a halogen atom, R ^1a and R ^1b is an ethylene group, R ^1c is a C _2-4 alkylene group, m and n are integers of 1 to 5, h1 and h2 are integers of 0 to 2, and j1 and j2 are 0 or 1, k is an integer of 0 to 2, q is an integer of 1 to 3, and the ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is as follows: An optical film in which the former / the latter (molar ratio) = 99/1 to 70/30.

(Iii) In the formula (1) and the formula (2), A is a cyclohexane residue, Z ¹ and Z ² are phenylene groups, R ^1a , R ^1b and R ^1c are ethylene groups, m, n And q is 1, h1, h2, j1, j2 and k are 0, and the ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is the former / the latter (Molar ratio) = 95 / 5-80 / 20 optical film.

The photoelastic coefficient of the polyester resin may be 7 × 10 ⁻¹² cm ² / dyn or less.

  The optical film of the present invention has low birefringence. For example, the retardation value may be 10 nm or less when unstretched.

  The optical film of the present invention may be stretched (stretching treatment). Such an optical film may be a film that is usually formed (for example, formed by melt extrusion) and stretched. The polyester film can be stretched at a temperature range below the melting point of the film resin and above the glass transition point. The stretching method may be uniaxial stretching or biaxial stretching. In the case of uniaxial stretching, longitudinal stretching or lateral stretching may be performed, and in the case of biaxial stretching, equal stretching or partial stretching may be performed. Further, the draw ratio may be about 1.1 to 10 times, for example, about 1.1 to 2.5 times or about 3.5 to 10 times, and about 2 to 5 times. Also good.

  The polyester resin and the polyester film have a high refractive index. Further, it has easy moldability, has a low birefringence, and also exhibits little birefringence due to molding. Therefore, a film subjected to stretch molding retains a high refractive index, low birefringence and easy moldability. For example, the optical film of the present invention may be an optical film that is uniaxially stretched or biaxially stretched and has a retardation value of 100 nm or less.

  Therefore, the film of the present invention is suitable for use in various parts such as an optical apparatus (for example, a display) requiring light weight, small size, and high performance. In particular, the optical film of the present invention may be an optical film for use in a display (or for a display). Moreover, the said film may contain the near-infrared absorption pigment | dye further.

  In addition, the member (for example, display member) provided with the said optical film is also contained in this invention.

  In the present invention, since a specific polyester resin is used, an optical film having a high refractive index and a low birefringence can be obtained. In particular, the optical film of the present invention can maintain low birefringence even after stretch molding. Such an optical film of the present invention has easy moldability and is useful as a film component for optical equipment.

  The optical film of the present invention is an esterification of a diol component composed of at least a diol having a fluorene skeleton (a diol component composed of a diol having a 9,9-bis (hydroxyaryl) fluorene skeleton) and a dicarboxylic acid component. A polyester resin obtained by reaction is included. Such a polyester resin usually has at least a repeating unit represented by the formula (1).

In A, the aliphatic hydrocarbon residue corresponds to a linear or branched C _1-10 aliphatic saturated hydrocarbon such as methane, ethane, propane, butane, isobutane, n-heptane, and n-octane. Groups (divalent groups) corresponding to linear or branched C _1-10 aliphatic unsaturated hydrocarbons such as ethylene, propylene and isobutene can be exemplified. It is a group (divalent group) corresponding to a linear or branched C _1-10 aliphatic saturated hydrocarbon. In A, the alicyclic hydrocarbon residue includes a group corresponding to a C _5-10 cycloalkane ring such as cyclopentane, cyclohexane, cycloheptane, cyclooctane (divalent group), cyclopentene, cyclohexene, cyclooctene, etc. Corresponding to a group corresponding to a C _5-10 cycloalkene ring (divalent group), polycyclic saturated hydrocarbon ring such as bornane, norbornane, adamantane (for example, bicyclic or tricyclic C _7-10 hydrocarbon ring) Groups corresponding to polycyclic unsaturated hydrocarbon rings such as bornene and norbornene (for example, bicyclic or tricyclic C _7-10 unsaturated hydrocarbon rings) (bivalent groups), etc. Can be illustrated. Usually, the alicyclic hydrocarbon residue is a group (divalent group) corresponding to a C _5-10 cycloalkane ring. In A, examples of the aromatic hydrocarbon residue include groups (divalent groups) corresponding to C _6-14 aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, biphenyl, and indene. A represents the alicyclic hydrocarbon residue or the aromatic hydrocarbon residue (for example, a divalent group corresponding to a C _5-10 cycloalkane ring or a divalent group corresponding to a C _6-10 aromatic hydrocarbon ring. In particular, a phenylene group is preferable.

  In A, the position of the bond of the hydrocarbon residue corresponding to A is not particularly limited, and may be an asymmetric position or a symmetric position. For example, when A is a cyclohexane ring, the hydrocarbon residue corresponding to A may be a 1,2-cyclohexane-diyl group, a 1,3-cyclohexane-diyl group, or a 1,4-cyclohexane-diyl group. It may be a group.

As the substituent R ⁴ , a linear or branched C _1-6 such as a halogen atom (bromine atom, chlorine atom, fluorine atom, etc.), an alkyl group (methyl group, ethyl group, butyl group, t-butyl group, etc.) Alkyl group) and the like. R ⁴ is usually often inert to the esterification reaction. The substitution number k of the substituent R ⁴ can be selected in the range of an integer of 0 or more according to the carbon number of A and the like, and may generally be an integer of about 0 to 8 (for example, 0 to 2). The substitution position of the substituent R ⁴ is not particularly limited and can be selected according to the type of A.

In Z ¹ and Z ² , examples of the aromatic hydrocarbon residue include a group (divalent group) corresponding to a C _6-14 aromatic hydrocarbon ring such as benzene, naphthalene, and anthracene. Z ¹ and Z ² are preferably a phenylene group or a naphthylene group (for example, a phenylene group).

Examples of the alkylene group represented by R ^1a and R ^1b include linear or branched C _2-4 alkylene groups such as an ethylene group, a propylene group, a trimethylene group, and a tetramethylene group. In R ^1a and R ^1b , the types of alkylene groups may be different from each other. Further, the types of the alkylene groups R ^1a and R ^1b may be different depending on the numbers of the coefficients m and n. A preferable alkylene group is a _C2-3 alkylene group (ethylene group, propylene group), and is usually an ethylene group.

In R ^2a , R ^2b , R ^3a and R ^3b , the alkyl group may be a linear or branched C chain such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a t-butyl group. _{A 1-5} alkyl group (especially _C1-4 alkyl group) can be illustrated. In R ^2a , R ^2b , R ^3a and R ^3b , examples of the alkoxy group include C _1-4 alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group (particularly C _1-3 alkoxy group). In R ^2a , R ^2b , R ^3a and R ^3b , examples of the aryl group include C _6-12 aryl groups such as a phenyl group and a naphthyl group. In R ^2a , R ^2b , R ^3a and R ^3b , cycloalkyl Examples of the group include C _5-10 cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group. In R ^2a , R ^2b , R ^3a and R ^3b , examples of the aralkyl group include C _6-12 aryl-C _1-4 alkyl groups such as a benzyl group.

The substitution numbers h1 and h2 of the substituents R ^2a and R ^2b may generally be an integer of about 0 to 3 (for example, 0 to 2). The substitution positions of the substituents R ^2a and R ^2b are not particularly limited, and can be selected according to the type of Z ¹ and Z ² . Preferred substituents R ^2a and R ^2b are C _1-4 alkyl groups (particularly methyl groups), and preferred substitution numbers h 1 and h 2 are integers of about 0 to 2 (eg, 0 or 1).

The substitution numbers j1 and j2 of the substituents R ^3a and R ^3b may generally be an integer of about 0 to 2 (eg, 0 or 1). Substitution position of the substituent ^{R 3a} and ^{R 3b} is not particularly limited, preferred substituents ^{R 3a} and ^{R 3b} _{are C 1-4} alkyl group (particularly methyl group), the preferred substituents which j1 and j2 0 or 1 (For example, 0).

  The number of repetitions m and n of the oxyalkylene unit is 0 or an integer of 1 or more, and is usually an integer of about 1 to 10, preferably 1 to 7, and more preferably about 1 to 5 (for example, 1 to 3). .

In the formula (2), A, R ⁴ and k are the same as described above. The repeating number q of the oxyalkylene unit is an integer of 1 or more. ^Examples of the alkylene group represented by R ^1c include linear or branched C _2-10 alkylene groups such as an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, and an octamethylene group. A preferred alkylene group is a linear or branched C _2-4 alkylene group (for example, ethylene group, tetramethylene group, etc.). In particular, when q ≧ 2, examples of the alkylene group represented by R ^1c include C _2-4 alkylene groups such as an ethylene group, a propylene group, and a butylene group, and q is 2 to 10, preferably 2 -7, More preferably, it may be an integer of about 2-5 (for example, 2-4). In the formula (2), the coefficient q is usually an integer of about 1 to 5, preferably about 1 to 3 (particularly 1).

  The polyester resin of the present invention only needs to have at least the repeating unit represented by the formula (1), and may be a homopolyester resin or a copolyester resin. Such a polyester resin may or may not contain the unit represented by the formula (2) as long as the birefringence does not increase. The ratio between the unit represented by the formula (1) and the unit represented by the formula (2) is the former / the latter (molar ratio) = 100/0 to 10/90 (for example, 100/0 to 30/70). ), Usually 99/1 to 50/50, preferably 99/1 to 60/40, more preferably 99/1 to 70/30, especially 97/3 to 75/25 (e.g. 95/5 to 80/20).

  Preferred polyester resins include (i) a polyester having a repeating unit represented by the following formula (1a) and a repeating unit represented by the following formula (2a) in which the dicarboxylic acid component is a benzenedicarboxylic acid (particularly terephthalic acid) component. Resin or (ii) a polyester resin having a repeating unit represented by the following formula (1b) and a repeating unit represented by the following formula (2b) in which the dicarboxylic acid component is a cyclohexanedicarboxylic acid component.

(In the formula, R ^1a and R ^1b represent a C _2-4 alkylene group, R ^1c represents a C _2-4 alkylene group, and R ^2a and R ^2b are the same or different and represent a C _1-4 alkyl group. , M and n are integers of 1 to 3, and h1 and h2 are integers of 0 to 2.)
The molecular weight of the polyester resin is not particularly limited and is, for example, a weight average molecular weight of 0.5 × 10 ^{4 to} 100 × 10 ⁴ , preferably 1 × 10 ⁴ to 50 × 10 ⁴ , and more preferably 1 × 10 ^{4 to} 25 ×. It may be about 10 ⁴ (for example, 1 × 10 ⁴ to 10 × 10 ⁴ ).

  The refractive index of the polyester resin is relatively high, for example, 1.55 or more (for example, about 1.59 to 1.7), preferably 1.60 or more (for example, about 1.60 to 1.65), More preferably, it is 1.605 or more (for example, about 1.605 to 1.63).

The photoelastic coefficient of the polyester resin is, for example, 7 × 10 ⁻¹² cm ² / dyn or less (for example, about 0.1 × 10 ^{−12 to} 6.5 × 10 ⁻¹² cm ² / dyn), preferably 6 × 10 ⁻¹² cm ² / dyn or less (for example, about 1 × 10 ^{−12 to} 5.5 × 10 ⁻¹² cm ² / dyn), more preferably 5 × 10 ⁻¹² cm ² / dyn or less (for example, 2 × 10 ^{−12 to} 4.5 × 10 ⁻¹² cm ² / dyn).

  The polyester resin is usually represented by at least a diol component composed of a diol represented by the following formula (3) (a diol having a 9,9-bis (hydroxyaryl) fluorene skeleton) and at least the following formula (5). It can be obtained by reacting a dicarboxylic acid component containing these dicarboxylic acids and their reactive derivatives. Furthermore, as described above, each of the diol component and the dicarboxylic acid component may be a single component, and the diol component and / or the dicarboxylic acid component may include a copolymer component. For example, the diol component may be configured by combining a diol represented by the formula (3) and a diol represented by the following formula (4).

(Wherein A, Z ¹ , Z ² , R ^1a , R ^1b , R ^1c , R ^2a , R ^2b , R ^3a , R ^3b , R ⁴ , m, n, h1, h2, j1, j2, k and q is the same as above)
The diol represented by the formula (3) includes 9,9-bis (hydroxyaryl) fluorenes and 9,9-bis (hydroxy (poly) alkoxyaryl) fluorenes.

As 9,9-bis (hydroxyaryl) fluorenes, 9,9-bis (4-hydroxyphenyl) fluorene (bisphenolfluorene, BPF); biscresol fluorene (BCF, for example, 9,9-bis (4-hydroxy) 9,9-bis (C _1-4 alkylhydroxyphenyl) fluorene, such as 3-methylphenyl) fluorene, 9,9-bis (3-hydroxy-4-methylphenyl) fluorene, etc .; 9,9-bis (diC _1-4 alkylhydroxyphenyl) fluorene such as 4-hydroxy-3,5-dimethylphenyl) fluorene, and 9,9-bis [2- (6-hydroxy) naphthyl] fluorene; 9 9,9-bis (2,9-bis [2- (6-hydroxy-5-methyl) naphthyl] fluorene) Roh or di _{C 1-4} alkyl hydroxy naphthyl) fluorene; corresponding to these compounds, the substituents ^{R 2a} and ^{R 2b} is like _{C 5-10} cycloalkyl group or a _{C 6-12} aryl group bis (hydroxyaryl) Fluorenes are mentioned.

Moreover, as 9,9-bis (hydroxy (poly) alkoxyaryl) fluorenes, 1 to 10 moles of C _2-4 alkylene oxide (preferably 1 to 1 mole) with respect to 1 mole of hydroxyl groups of bis (hydroxyaryl) fluorenes. 5 mol, especially 1 to 3 mol) or a compound to which about 1 to 5 mol (preferably 1 to 3 mol, particularly 1 mol) of C _2-8 haloalkanol such as 3-chloropropanol is added. Typical 9,9-bis (hydroxy (poly) alkoxyaryl) fluorenes include 9,9-bis such as 9,9-bis (4-hydroxyethoxyphenyl) fluorene (bisphenoxyethanol fluorene, BPEF). [4- (hydroxy _{C 2-3} alkoxy) phenyl] fluorene; 9,9-bis (4-hydroxyethoxy-3-methylphenyl) fluorene (biscresol ethanol fluorene, BCEF), 9,9- bis (4-hydroxy 9,9-bis (alkylhydroxy C _2-3 alkoxyphenyl) fluorene such as isopropoxy-3-methylphenyl) fluorene; 9 such as 9,9-bis (4-hydroxyethoxy-3,5-dimethylphenyl) fluorene , 9-bis (di-hydroxy _{C 2-3} Turkey hydroxyphenyl) fluorene; 9,9-bis (4-hydroxyethoxy-3-phenyl) 9,9-bis fluorene (cycloalkyl hydroxy _{C 2-3} alkoxyphenyl) fluorene; 9,9-bis (4 9 such as 9,9-bis (arylhydroxy C _2-3 alkoxyphenyl) fluorene such as -hydroxyethoxy- _3- phenylphenyl) fluorene and 9,9-bis [2- (6-hydroxyethoxy) naphthyl] fluorene 9,9-bis (mono or dialkylhydroxy C ₂ ) such as 9,9-bis (hydroxyC _2-3 alkoxynaphthyl) fluorene; 9,9-bis [2- (6-hydroxyethoxy-5-methyl) naphthyl] fluorene _-3 alkoxynaphthyl) fluorene and the like.

Among these compounds, as 9,9-bis (hydroxyaryl) fluorenes, for example, 9,9-bis (4-hydroxyphenyl) fluorene (for example, BPF), 9,9-bis (C _1-4 ). Alkylhydroxyphenyl) fluorene (eg BCF) is preferred. The 9,9-bis (hydroxy (poly) alkoxyaryl) fluorenes, for example, 9,9-bis [4- (hydroxy _{C 2-3} alkoxy) phenyl] fluorene (e.g., BPEF), 9,9-bis (Alkylhydroxy C _2-3 alkoxyphenyl) fluorene (for example, BCEF) and the like are preferable. As the diol component represented by the above formula (3), 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is often used. These compounds can be used alone or in combination of two or more.

  The diol represented by the above formula (3) (for example, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene) has a rigid fluorene ring and two aromatic rings, and thus has heat resistance. In addition to improving the refractive index and the refractive index, it is extremely effective as a monomer with reduced molecular birefringence, possibly because of the conformation in which the planes of these three aromatic rings are orthogonal to each other.

The diol represented by the formula (4) can be used as a copolymerization component and is not always necessary. Examples of the diol represented by the formula (4) include alkylene glycol (for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, tetramethylene glycol (1,4-butanediol), hexanediol, neo Linear or branched C _2-12 alkylene glycols such as pentyl glycol, octanediol, decane diol, etc.) (poly) oxyalkylene glycols (for example, di to tetra C such as diethylene glycol, triethylene glycol, dipropylene glycol) _2-4 alkylene glycol etc.). These diols can be used alone or in combination of two or more. Preferred diols are linear or branched C _2-10 alkylene glycols, especially linear chains such as C _2-6 alkylene glycols (eg, ethylene glycol, propylene glycol, tetramethylene glycol (1,4-butanediol)). Or branched C _2-4 alkylene glycol). As the diol, at least ethylene glycol is often used.

  The diol represented by the above formula (4) (for example, ethylene glycol) is useful as a copolymer component for enhancing polymerization reactivity and imparting flexibility to the resin. In addition, since the refractive index, heat resistance, and water absorption may be reduced due to the introduction of the copolymer component, in general, the copolymerization ratio seems to be as small as possible.

  The ratio (molar ratio) between the diol represented by the formula (3) and the diol represented by the formula (4) is the former / the latter = 100/0 to 10/90 (for example, 100/0 to 30/70). A range of about 99/1 to 50/50, preferably 99/1 to 60/40, more preferably 99/1 to 70/30, especially 97/3 to 75/25 (eg 95 / 5-80 / 20).

  If necessary, the diols represented by the above formulas (3) and (4) may be added to alicyclic diols (for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2-bis). Bis (hydroxycycloalkyl) alkanes such as (4-hydroxycyclohexyl) propane, bis ((hydroxyalkoxy) cycloalkyl) alkanes such as 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane), Aromatic diols (for example, biphenol, bis (hydroxyaryl) alkanes such as 2,2-bis (4-hydroxyphenyl) propane, bis (2,2-bis (4- (2-hydroxyethoxy) phenyl) propane, etc. (Hydroxyalkoxy) aryl) alkane, xylylene glycol, etc.) It may be used in conjunction look. These diols may be used alone or in combination of two or more. Furthermore, you may use together polyols, such as glycerol, a trimethylol propane, a trimethylol ethane, a pentaerythritol, as needed.

Among the dicarboxylic acid components containing the dicarboxylic acid represented by the formula (5) and their reactive derivatives, the aliphatic dicarboxylic acid component includes aliphatic saturated dicarboxylic acids (for example, malonic acid, succinic acid, glutaric acid, adipine acid, pimelic acid, suberic acid, azelaic acid, C _1-10 alkane such as sebacic acid - such as dicarboxylic acid), aliphatic unsaturated dicarboxylic acids (e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid and the like C _2-10 alkene-dicarboxylic acid, etc.), their reactive derivatives (acid anhydrides such as succinic anhydride, lower C _1-4 alkyl esters such as dimethyl ester and diethyl ester, acid halides corresponding to dicarboxylic acid, etc. And derivatives capable of forming esters). Usually, the aliphatic dicarboxylic acid component is a C _2-8 alkane-dicarboxylic acid or a reactive derivative thereof.

Among the dicarboxylic acid components including the dicarboxylic acid represented by the formula (5) and their reactive derivatives, the alicyclic dicarboxylic acid component includes cycloalkanedicarboxylic acids (cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid). _{C5- 10} cycloalkane-dicarboxylic acid such as 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid), cycloalkene dicarboxylic acids (C _5-10 cycloalkene such as tetrahydrophthalic acid) - dicarboxylic acid), polycyclic alkane dicarboxylic acids (Bol nonanedicarboxylic acid, norbornane carboxylic acid, di-or tricyclic C _7-10 alkanes such as adamantane dicarboxylic acid - dicarboxylic acid), polycyclic alkene dicarboxylic acids (Bol annual carboxylic acid Di- or tricyclic C _7-10 alkene such as norbornene dicarboxylic acid - dicarboxylic acid), acid anhydrides such as those reactive derivatives (hexahydrophthalic anhydride, dimethyl ester, lower C _1-4 alkyl esters such as diethyl ester, dicarboxylic Examples thereof include derivatives capable of forming an ester such as acid halides corresponding to acids. Usually, the alicyclic dicarboxylic acid component is C _5-10 cycloalkane-dicarboxylic acid or a reactive derivative thereof.

Among the dicarboxylic acid components including the dicarboxylic acid represented by the formula (5) and their reactive derivatives, the aromatic dicarboxylic acid component includes C _6-14 such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and the like. C _12-14 biphenyl-dicarboxylic acid such as arene-dicarboxylic acid, biphenyl-4,4′-dicarboxylic acid or reactive derivatives thereof (acid anhydride such as phthalic anhydride, lower C ₁ such as dimethyl ester, diethyl ester, etc. _-4 alkyl esters, derivatives capable of forming esters such as acid halides corresponding to dicarboxylic acids), and the like. Usually, the aromatic dicarboxylic acid component is C _6-12 arene dicarboxylic acid or a reactive derivative thereof.

  These dicarboxylic acid components can be used alone or in combination of two or more. The ratio (molar ratio) between the alicyclic dicarboxylic acid or aromatic dicarboxylic acid and the aliphatic dicarboxylic acid is the former / the latter = 100/0 to 50/50, preferably 95/5 to 70/30, more preferably 90. It may be about / 10 to 80/20. Furthermore, if necessary, a branched structure may be introduced into the polyester resin by using a polycarboxylic acid such as tricarboxylic acid or tetracarboxylic acid in combination. Of these dicarboxylic acid components, 1,4-cyclohexanedicarboxylic acid or reactive derivatives thereof (such as dimethyl 1,4-cyclohexanedicarboxylate) and terephthalic acid or reactive derivatives thereof (such as dimethyl terephthalate) are often used. .

  Various properties such as refractive index, birefringence, mechanical strength and moldability of the produced polyester resin film can be adjusted by the dicarboxylic acid component, so the type of dicarboxylic acid component should be selected according to the purpose. Can do.

  The ratio (molar ratio) between the dicarboxylic acid component and the diol component is usually the former / the latter = 1.5 / 1 to 0.7 / 1, preferably 1.2 / 1 to 0.8 / 1 (especially 1 About 1/1 to 0.9 / 1).

  For a method for producing a polyester resin, JP 2004-315676 A (Embodiment of the Invention) may be referred to.

  The production method of the polyester resin is not particularly limited, and is a conventional method such as a transesterification method, a melt polymerization method (direct polymerization method, etc.), a solution polymerization method in which an organic solvent is reacted, an interfacial polymerization method using an acid halide. Etc. can be exemplified. When a dicarboxylic acid and bis (hydroxyaryl) fluorenes and, if necessary, a copolymer component (such as alkylene glycol) are reacted directly by a polymerization method, the esterification reaction proceeds smoothly even under extremely mild conditions.

Although the reaction can be carried out in the absence of a catalyst, it is preferable to use a catalyst in order to prevent the resin from being colored and to obtain a resin having a predetermined polymerization degree under milder conditions. As the catalyst, various catalysts used for producing a polyester resin, for example, a metal catalyst can be used. As the metal catalyst, for example, a metal compound containing an alkali metal (such as sodium), an alkaline earth metal (such as magnesium or barium), or a transition metal (such as zinc, cadmium, lead, or cobalt) is used. Examples of the metal compound include alkoxide, organic acid salt (acetate, propionate, etc.), inorganic acid salt (borate, carbonate, etc.), metal oxide and the like. These catalysts can be used alone or in combination of two or more. The amount of the catalyst used is, for example, about 0.01 × 10 ^{−4 to} 100 × 10 ⁻⁴ mol, preferably about 0.1 × 10 ⁻⁴ to 10 × 10 ⁻⁴ mol, with respect to the dicarboxylic acid component. Also good.

The reaction can usually be performed in an inert gas (nitrogen, helium, etc.) atmosphere. The reaction may be carried out under normal pressure or under reduced pressure (for example, 1 to 100 torr (about 1 × 10 ² to 1 × 10 ⁴ Pa)). The reaction temperature can be about 150-270 degreeC (preferably 180-260 degreeC, More preferably, it is 200-250 degreeC) grade, for example. After completion of the reaction, the resin may be purified by a conventional method if necessary.

  When an aliphatic dicarboxylic acid is used as the dicarboxylic acid represented by the formula (5), the resulting polyester resin has easy moldability.

  When an alicyclic dicarboxylic acid is used as the dicarboxylic acid represented by the formula (5), the resulting polyester resin has a very high refractive index and a very low birefringence. In addition, since the molding fluidity is excellent, a small amount of copolymer components such as alkylene glycol (ethylene glycol, etc.) may be used, and the original physical properties of the resin (for example, refractive index, heat resistance, water absorption, etc.) can be maintained. it can.

  Furthermore, when an aromatic dicarboxylic acid is used as the dicarboxylic acid represented by the formula (5), the mechanical strength and the refractive index are improved. In addition, although molding fluidity decreases and birefringence generally increases due to stress strain and molecular orientation, diol (bis (hydroxyaryl) fluorenes) having a fluorene skeleton and aromatic dicarboxylic acid are polymerized. As a result, a polyester resin film having a high refractive index and low birefringence can be obtained. Further, when alkylene glycol (ethylene glycol or the like) is used as a copolymer component of the diol component, fluidity can be improved and a resin suitable for stretch molding can be obtained.

  The polyester resin used in the present invention may be used as a resin composition by adding various additives as necessary. Examples of additives include plasticizers (esters, phthalic compounds, epoxy compounds, sulfonamides, etc.), flame retardants (inorganic flame retardants, organic flame retardants, colloid flame retardants, etc.), stabilizers ( Antioxidants, ultraviolet absorbers, heat stabilizers, etc.), colorants (pigments such as carbon black and titanium dioxide), antistatic agents, fillers (oxide-based inorganic fillers, non-oxide-based inorganic fillers, metals) Powder, etc.), foaming agents, antifoaming agents, lubricants, mold release agents (natural waxes, synthetic waxes, linear fatty acids or metal salts thereof, acid amides, etc.) and the like. Moreover, in order to improve a refractive index and heat resistance, a sulfur compound, polysilane, etc. may be included. These additives may be used alone or in combination of two or more.

  The polyester resin used in the present invention may be used by dispersing other resins as necessary. For example, when the polycarbonate is dispersed, the polyester resin of the present invention and the polycarbonate are often completely compatible, and a transparent alloy can be produced simply by kneading the polyester resin of the present invention and the polycarbonate. In that case, the birefringence of the polyester resin of the present invention is very small, and the birefringence of the mixed resin of the polyester resin of the present invention and the polycarbonate can be freely controlled according to the type and amount of polycarbonate added. A resin may be used as a raw material for the optical film.

  Furthermore, the polyester resin used in the present invention may contain an infrared absorbing dye, if necessary.

  The infrared absorbing dye may be any dye (or compound) having absorption (or absorption area) in at least the infrared region, in particular, at least the near infrared region (for example, about 800 to 1100 nm). Examples of such dyes include polymethine dyes (polymethine dyes, cyanine dyes, azurenium dyes, pyrylium dyes, squarylium dyes, croconium dyes, etc.), phthalocyanine dyes (phthalocyanine compounds), naphthalocyanine dyes (naphthalocyanine dyes). Compound), azo chelate dyes, dithiol dyes (metal chelate dyes such as dithiol nickel complex dyes), aminium dyes, imonium dyes (such as immonium dyes, diimmonium dyes), quinone dyes (anthraquinone dyes) Dyes, naphthoquinone dyes, etc.), triphenylmethane dyes and the like. Among these infrared absorbing dyes, for example, cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, dithiol nickel complex dyes, and the like may be used to increase the absorption in the wavelength region of 800 to 900 nm. Moreover, you may improve the absorptivity of a 900 nm or more wavelength range using a cyanine dye, a dithiol nickel complex dye, a diimmonium dye, etc.

  Typical infrared absorbing dyes (especially near infrared absorbing dyes) that can be used in the present invention include phthalocyanine dyes, dithiol dyes (or dithiolene dyes such as dithiol nickel complex dyes), diimmonium dyes, and the like. . These infrared absorbing dyes may be, for example, infrared absorbing dyes exemplified in JP-A No. 2006-119383.

(Phthalocyanine dye)
Examples of the phthalocyanine dye include a compound represented by the following formula (6).

(In the formula, R ^p is the same or different and is a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, an amino group, an amide group, an imide group, or an arylthio group; R ^p adjacent to each other may form a ring, a represents 0 or an integer of 1 to 4. M _p represents a hydrogen atom, a divalent to hexavalent metal atom, or a group thereof. (It is an oxide, and the valence may be supplemented with a counter anion.)
The group represented by R ^p (for example, an alkyl group, an amino group, etc.) may have a substituent, and examples of the substituent include a hydrocarbon group [for example, an alkyl group (for example, a C _{1- 6} alkyl group), cycloalkyl group (C _5-8 cycloalkyl group such as cyclohexyl group), aryl group (C _6-10 aryl group such as phenyl group, preferably C _6-8 aryl group) An aralkyl group (such as a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group), an alkoxy group (such as a C _1-4 alkoxy group such as a methoxy group or an ethoxy group), an acyl group (such as an acetyl group) C, such as _1-6 acyl group), and a halogen atom (fluorine atom, such as chlorine atom), a hydroxyl group, a nitro group, a cyano group, an amino group [an amino group, a substituted amino group (dimethylamino group Mono or (such as C _1-4 alkylamino group) dialkylamino group)], and the like. The substituents may be substituted singly or in combination of two or more.

In R ^p of the formula (6), examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the alkyl group include a C _1-20 alkyl group (preferably a C _3-10 alkyl group) such as a methyl group, a t-butyl group, a t-amyl group (1,1-dimethylpropyl group), and a trifluoromethyl group. Examples of the alkoxy group include an alkoxy group corresponding to the alkyl group such as a butoxy group [for example, a C _1-20 alkoxy group (preferably a C _3-10 alkoxy group)]. Examples of the aryl group include a C _6-10 aryl group such as a phenyl group (preferably a C _6-8 aryl group). The aryloxy group includes an aryloxy group corresponding to the aryl group such as a phenoxy group [ For example, C _6-10 aryloxy group (preferably C _6-8 aryloxy group)] and the like can be mentioned. Examples of the aralkyl group include a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group (preferably a C _6-8 aryl-C _1-2 alkyl group). As the amino group, mono- or di-C _1-10 alkylamino group (preferably mono- or di-C _1-4 alkylamino group) such as amino group and dimethylamino group, alkylideneamino group (for example, octadecanylideneamino group) (—NH═CH—C ₁₇ H ₃₅ ) and the like. Examples of the amide group include an acylamide group (such as an acetamide group), and examples of the imide group include a methylphthalimide group. Examples of the arylthio group include C _6-10 arylthio groups (preferably C _6-8 arylthio groups) such as a phenylthio group and a p-methylphenylthio group. The adjacent R ^p may form a ring, for example, a hydrocarbon ring such as an arene ring (such as a benzene ring) or a cycloalkane ring (such as a cycloalkane ring). You may have the same substituent (an alkyl group etc.).

Substitution position of group R ^p is not particularly limited and may be any of 3-6 position of the benzene ring.

  In the formula (6), examples of the metal atom represented by Mp include alkaline earth metals (Mg, etc.), periodic table group 13 metals (Al, etc.), periodic table group 14 metals (Si, Ge, Sn, Pb, etc.), transition metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd, Rh, etc.) and the like.

The counter anion (or valence a supplement group), for example, a hydroxyl group, a halide ion (chloride ion, bromide ion, etc. iodide ion), tri C ₁ such as trialkyl silyl group (trihexyl silyloxy _-10 alkylsilyloxy groups, etc.), metal acid ions (such as hexafluoroantimonate ions (SbF ₆ ⁻ )), inorganic acid ions (halogen acid ions such as perchlorate ions, hexafluorophosphate ions (PF ₆₎ ^-) ions containing phosphorus, such as tetrafluoroborate ion (BF 4 _- ion containing boron, ^etc.)) and the like.

  These phthalocyanine dyes may be used alone or in combination of two or more.

(Dithiol dye)
Examples of the dithiol dye include a compound represented by the following formula (7).

(In the formula, X and Y are the same or different and each represents an oxygen atom, a sulfur atom, NH or NH ₂ , and at least two of the two X and Y are sulfur atoms. R ^t is the same. Or a different cyano group or a phenyl group which may have a substituent, and R ^t substituted on an adjacent carbon atom may form a benzene ring or a naphthalene ring. The transition metal atom of which may be supplemented with a counter anion.)
In the above formula, examples of the tetracoordinate transition metal atom Mt include Ti, V, Cr, Co, Ni, Zr, Mo, Fe, Ru, Pd, Os, and Pt. Preferable Mt is Ni (dithiol nickel complex dye). Examples of the substituent include the same substituents as those exemplified above (for example, a substituted amino group such as an alkyl group, an aryl group, an alkoxy group, a halogen atom, and a dimethylamino group).

  These dithiol dyes may be used alone or in combination of two or more.

(Diimonium dye)
Examples of the diimmonium dye include a compound (aromatic diimmonium compound) represented by the following formula (8) or (9).

(Wherein R ⁱ¹ , R ⁱ² , R ⁱ³ , R ⁱ⁴ , R ⁱ⁵ , R ⁱ⁶ , R ⁱ⁷ and R ⁱ⁸ are the same or different and are alkyl groups, and R ^j1 , R ^j2 , R ^j3 and R ^j4 Are the same or different and are a hydrogen atom or a fluorine atom, and X ²⁻ is a divalent anion.)

(In the formula, R ⁱ⁹ , R ⁱ¹⁰ , R ⁱ¹¹ , R ⁱ¹² , R ⁱ¹³ , R ⁱ¹⁴ , R ⁱ¹⁵ and R ⁱ¹⁶ are the same or different and are alkyl groups, and R ^j5 , R ^j6 , R ^j7 and R ^j8 Are the same or different and each represents a hydrogen atom or a fluorine atom, and Z ⁻ represents a monovalent anion.)
In the above formula (8) or (9), examples of the alkyl group include the above-exemplified alkyl groups, for example, C _1-10 alkyl groups such as methyl group, ethyl group, propyl group, and butyl group, preferably C _1-8. Examples thereof include an alkyl group, more preferably a C _1-6 alkyl group.

In the formula (8), the divalent anion X ²⁻ is not particularly limited, and examples thereof include oxygen ions (O ²⁻ ), inorganic acid ions [carbonate ions (CO ₃ ²⁻ ), sulfate ions (SO ₄ ). ^2- ) etc.], organic acid ions [oxalate ion (C ₂ O ₄ ²⁻ ) etc.] and the like. In the formula (9), examples of the monovalent anion Z ⁻ include the same anions as the counter anion, and in particular, metal acid ions (such as hexafluoroantimonate ion (SbF ₆ ⁻ )), Inorganic acid ion (halogen ion such as perchlorate ion, ion containing phosphorus such as hexafluorophosphate ion (PF ₆ ⁻ ), ion containing boron such as tetrafluoroborate ion (BF ₄ ⁻ ), etc. Etc.) are preferred.

  Such infrared absorbing dyes may be used alone or in combination of two or more. Usually, since the infrared absorption wavelength region (particularly the near-infrared absorption wavelength region) and the maximum absorption wavelength of the pigment are slightly different, it is preferable to use two or more types of pigment. In particular, it is preferable to use at least two kinds of dyes selected from phthalocyanine dyes, dithiol dyes, diimmonium dyes, and cyanine dyes as infrared absorbing dyes.

  The ratio of the infrared absorbing dye (the ratio of the total when two or more infrared absorbing dyes are used in combination) is 0.01 to 10 parts per 100 parts by weight of the polyester resin (or resin component). Parts by weight, preferably 0.03 to 8 parts by weight, more preferably about 0.05 to 6 parts by weight (for example, 0.1 to 4 parts by weight), usually 0.01 to 3 parts by weight. It may be a degree. For example, when two kinds of infrared absorbing dyes are used in combination, the ratio of each infrared absorbing dye can be appropriately selected according to the kind of the dye, for example, one infrared absorbing dye / the other infrared absorbing dye (weight ratio). = 99/1 to 1/99, preferably 97/3 to 3/97, more preferably about 95/5 to 5/95.

  In the optical film of the present invention, the infrared absorbing pigment is usually contained in a form dispersed in the resin (or film). The average light transmittance in the visible light region (for example, 400 to 800 nm) of the optical film may be, for example, about 30 to 100%, preferably about 35 to 90%, and more preferably about 40 to 80%. Moreover, the average light transmittance in the near infrared region (for example, 800 to 1200 nm) of the optical film may be, for example, 1 to 50%, preferably 3 to 40%, and more preferably about 5 to 35%. . In addition, the said optical film can satisfy | fill the said average light transmittance easily by using the said infrared rays absorption pigment | dye in the said ratio. In the present invention, even if the infrared absorbing dye is contained in the polyester resin, it is uniformly dispersed, so that the optical film is provided with infrared absorptivity (particularly, near infrared absorptivity) while having excellent transparency. can do.

  The optical film (or polyester film) is not particularly limited, and can be prepared by, for example, a casting method (solution casting method), an extrusion method (a melt extrusion method such as an inflation method or a T-die method), a calendar method, or the like. The method for preparing the optical film (or polyester film) is usually a melt extrusion method in many cases. If necessary, a film (infrared shielding film) having infrared absorbing ability may be prepared by adding the infrared absorbing dye to the polyester resin in the film preparation process. The method for preparing the infrared shielding film is not particularly limited. For example, the polyester resin and the infrared absorbing dye are melt-kneaded and homogenized (dispersed), and then the film (infrared shielding film) is used. ) May be used. In order to prepare the film, when using an extruder (single screw or twin screw extruder) attached with a T die, the infrared absorbing pigment is dispersed in the polyester resin and the film (infrared shielding film). The film forming step can be performed continuously, which is industrially advantageous.

  The optical film of the present invention may be an unstretched film, but may be a stretched film from the viewpoint of mechanical properties and the like.

  Stretch molding can be performed while heating a film once molded by a conventional method to an appropriate temperature between the melting point of the resin and the glass transition point. The stretching may be either biaxial stretching or uniaxial stretching. Biaxial stretching can be performed by stretching the film in two longitudinal and lateral directions, and uniaxial stretching can be performed by stretching in one longitudinal or lateral direction. Biaxial stretching may be either equal stretching having the same strength and shrinkage in the vertical and horizontal directions, or partial stretching in which the vertical and horizontal strengths and shrinkage are different. On the other hand, the uniaxial stretching may be either longitudinal stretching or lateral stretching.

  The stretching ratio may be about 1.1 to 10 times (preferably 1.2 to 8 times, more preferably 1.5 to 6 times) in each direction in uniaxial stretching and biaxial stretching. Further, the stretching ratio in each direction in uniaxial stretching or biaxial stretching is 1.1 to 2.5 times, preferably 1.2 to 2.3 times, more preferably 1.5 to 2.2 times, respectively. There may be. Moreover, in uniaxial stretching or biaxial stretching, the stretching ratio in each direction may be 3.5 to 10 times, preferably 3.8 to 8 times, and more preferably 4 to 6 times. For example, in the case of biaxial stretching, even stretching (for example, 1.5 to 5 times in both longitudinal and transverse directions) is partially stretched (for example, 1.1 to 4 times in the longitudinal direction and 2 to 6 times in the transverse direction). Stretching). In the case of uniaxial stretching, the stretching may be longitudinal stretching (for example, 2.5 to 8 times stretching in the longitudinal direction) or lateral stretching (for example, 1.2 to 5 times stretching in the transverse direction).

  The stretching method is not particularly limited. In the case of uniaxial stretching, either a wet stretching method or a dry stretching method may be used. However, a tenter method that is excellent in uniformity of stretch thickness is preferable.

  Since the polyester film has excellent mechanical properties (for example, tensile strength), dimensional stability, heat resistance, and chemical stability, the film thickness can be reduced. When the stretching treatment is performed, the tensile strength is further increased, and an extremely thin film can be obtained. The thickness of the optical film of the present invention can be selected from the range of about 1 to 1000 μm depending on the application, and may be, for example, 1 to 200 μm, preferably 5 to 150 μm, and more preferably about 10 to 120 μm.

  The polyester film of the present invention is amorphous and has high crystallization characteristics and transparency. Further, since it exhibits excellent melt viscoelastic properties, it has excellent fluidity and moldability, hardly causes residual stress strain and molecular orientation, and has extremely low birefringence. Furthermore, since the mechanical strength and the refractive index are high, the film can be thinned, and the polyester film of the present invention can be stretched without causing optical distortion due to molding. In addition, since the dependency of birefringence on the draw ratio is small, a film having uniform birefringence can be produced. The retardation value (Re value) of the optical film of the present invention is, for example, 0 to 100 nm, preferably 0 to 50 nm, more preferably 0 to 30 nm (for example, 0.1 to 20 nm) in an unstretched (or unstretched film). In particular, it may be about 10 nm or less (for example, 0.5 to 5 nm). The optical film of the present invention can maintain the low birefringence as described above at a high level even if it is stretched. For example, the retardation value (Re value) of the optical film of the present invention is, for example, 0 to 200 nm (for example, 1 to 150 nm), preferably 100 nm or less (for example, 3 to 100 nm), more preferably 80 nm or less in the stretched film. (For example, 5 to 60 nm), particularly about 50 nm or less (for example, 10 to 40 nm). The polyester film of the present invention has high functionality and high performance, and is easily moldable and can be mass-produced. Furthermore, it is effective for making the equipment thinner and lighter.

  The polyester film of the present invention is useful as various films. In particular, since the polyester film of the present invention has excellent optical properties, it is useful as a high-performance and high-performance optical film.

  The polyester film of the present invention has a high refractive index and is excellent in fluidity. Therefore, it is possible to obtain a molded product having excellent easy moldability, small expression of birefringence due to molding orientation, and less optical distortion and coloring. Furthermore, the dependency of birefringence on the draw ratio is small, and it is excellent in the production of a film having uniform birefringence, and is suitable for an optical film for display.

  The polyester film of the present invention can be widely applied not only to the field of electronic equipment including an optical film for display but also to the fields of electricity, machinery, automobiles, packaging containers and daily necessities.

  The optical film of the present invention has a high refractive index and a low birefringence, is excellent in moldability and can be mass-produced, and thus can be used as various high-performance optical films. As an optical film, a polarizing film, a polarizing element and a polarizing plate protective film constituting the polarizing film, a retardation film, an alignment film (alignment film), a viewing angle expansion (compensation) film, a diffusion plate (film), a prism sheet, a light guide plate , Brightness enhancement film, near infrared absorption film, reflection film, antireflection (AR) film, antireflection (LR) film, antiglare (AG) film, transparent conductive (ITO) film, anisotropic conductive film (ACF), Examples thereof include an electromagnetic wave shielding (EMI) film, an electrode substrate film, a color filter substrate film, a barrier film, a color filter layer, a black matrix layer, an adhesive layer or a release layer between optical films.

  The optical film of the present invention may be a single film having two or more functions of such an optical film, or a part of a film (composite film) having two or more of such optical films or All may be configured. In other words, a composite film may be composed of the optical film of the present invention and another optical film, or a composite film may be composed of only the optical film of the present invention. As such a composite film, for example, a polarizing film in which a polarizing element and its protective film are integrated, a film in which a polarizing plate protective film is provided with a retardation film function, a polarizing element, a protective film, and an integrated film thereof A polarizing film having a function corresponding to at least one film selected from a retardation film, an antireflection film, an antiglare film, a light diffusing film, a light collecting film, and a reflective film, on at least one film selected from Etc. Furthermore, a film provided with a polarizing plate protection function on a retardation film, a film provided with a viewing angle expansion (compensation) function on a polarizing film, a film provided with a prism sheet condensing function on a light guide plate, and a prism sheet provided on a light guide plate The film etc. which provided the function and the light-diffusion function of the diffusion plate are also included. Moreover, since the optical film of the present invention has a high refractive index, it is possible to give the polarizing protective film the function of a high refractive index layer of an antireflection film without bothering the function.

  Further, as described above, since the optical film of the present invention is excellent in dispersibility of fillers, pigments, etc., instead of methods such as coating, sputtering, impregnation, etc., in the polymer, inorganic fillers, pigments, pigments, carbon The function which another optical film has can be simply provided to the optical film of this invention by disperse | distributing etc. For example, in addition to a film in which the above-described infrared absorbing dye is used as an alternative to an infrared shielding film coated with an infrared absorbing dye, a film in which a metal component is dispersed as an alternative to an electromagnetic wave shielding film in which a metal component is sputtered, It can also be used as a film in which an infrared absorbing dye and a metal component are dispersed, a film imparted with conductivity or antistatic ability by carbon, a film in which pigment or carbon black is dispersed, a color filter layer, a black matrix layer, or the like. it can.

  In particular, the film of the present invention is useful as an optical film for use in an apparatus display. As a display member (or display) provided with such an optical film of the present invention, specifically, an FPD device (for example, a monitor of a personal computer, a television, a mobile phone, a car navigation, a touch panel) (for example, LCD, PDP, etc.).

  In addition, as other examples of use of the stretched polyester film of the present invention utilizing transparency, toughness, electrical insulation, dimensional stability, etc., magnetic recording films (for example, floppy (registered trademark) disks), for drawing and copying Film (for example, photographic film or X-ray film), film for electrical insulation (for example, film for covering wire or cable), etc. are used, and also used as a packaging film utilizing heat shrinkability by biaxial stretching treatment can do.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

  The film was evaluated by the following method.

(1) Refractive index A multi-wavelength Abbe refractometer “DR-M2 / 1550” (manufactured by Atago Co., Ltd.) was used to measure at a light source wavelength of 589 nm and a measurement temperature of 20 ° C.

(2) Measurement of light transmittance In Examples 1 to 4 and Comparative Examples 1 and 2, the light transmittance in the range of 300 to 800 nm was measured using “U-3010” (manufactured by HITACHI). In No. 6, "UV-3600" (manufactured by SHIMADZU) was used, and the light transmittance in the range of 300 to 1500 nm was measured. The average light transmittance in the visible light region was measured in the range of 400 to 800 nm, and the average light transmittance in the near infrared light region was measured in the range of 800 to 1200 nm.

(3) Phase difference measurement “KOBRA-WR” (manufactured by Oji Scientific Instruments Co., Ltd.) was used, the measurement method was the parallel Nicol rotation method, and the retardation value (Re value) was measured at a wavelength of 587 nm.

(4) Evaluation of stretchability Using “TYPE HW-500” (manufactured by Ooba Kikai), stretching was performed at a temperature higher by about 15 to 20 ° C. than the glass transition temperature.

Example 1
To the reactor, 52 parts by weight of 1,4-cyclohexanedicarboxylic acid, 41 parts by weight of ethylene glycol and 105 parts by weight of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene were added and gradually heated and melted while stirring. After the esterification reaction, 0.06 part by weight of germanium oxide was added, and ethylene glycol was removed while gradually increasing the temperature and reducing the pressure until reaching 270 ° C. and 1 Torr or less. Thereafter, the contents were taken out of the reactor, and pellets of a copolyester resin having a fluorene skeleton were obtained. 80 mol% of the diol component introduced into the polyester resin was derived from 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene. The polyester resin had a weight average molecular weight Mw of 47000 and a glass transition temperature Tg of 120 ° C.

  The obtained polyester resin pellets were melt-extruded T-die film molded at 220 ° C. to obtain an optical film having a thickness of 100 μm.

(Example 2)
To the reactor was added 52 parts by weight of 1,4-cyclohexanedicarboxylic acid, 41 parts by weight of ethylene glycol, and 120 parts by weight of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene. After the esterification reaction, 0.06 part by weight of germanium oxide was added, and ethylene glycol was removed while gradually increasing the temperature and reducing the pressure until reaching 270 ° C. and 1 Torr or less. Thereafter, the contents were taken out of the reactor, and pellets of a copolyester resin having a fluorene skeleton were obtained. 90 mol% of the diol component introduced into the polyester resin was derived from 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene. The polyester resin had a weight average molecular weight Mw of 41,000 and a glass transition temperature Tg of 125 ° C.

  The obtained polyester resin pellets were melt-extruded T-die film molded at 220 ° C. to obtain an optical film having a thickness of 100 μm.

(Example 3)
To the reactor, 58 parts by weight of terephthalic acid, 41 parts by weight of ethylene glycol and 92 parts by weight of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene were added and gradually heated and melted to 160 to 230 ° C. while stirring. After the esterification reaction, 0.06 part by weight of germanium oxide was added, and ethylene glycol was removed while gradually increasing the temperature and reducing the pressure until reaching 270 ° C. and 1 Torr or less. Thereafter, the contents were taken out of the reactor, and pellets of a copolyester resin having a fluorene skeleton were obtained. 70 mol% of the diol component introduced into the polyester resin was derived from 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene. This polyester resin had a weight average molecular weight Mw of 40000 and a glass transition temperature Tg of 140 ° C.

  The obtained polyester resin pellets were melt-extruded T-die film molded at 220 ° C. to obtain an optical film having a thickness of 100 μm.

Example 4
The copolymerized polyester film obtained in Example 1 was uniaxially stretched at a stretching temperature of 140 ° C. to obtain a stretched film.

(Comparative Example 1)
Polycarbonate (manufactured by Teijin Chemicals Ltd., Panlite 5503) was used, and melt extrusion T-die film molding was performed at 240 ° C. to obtain an optical film having a thickness of 100 μm.

(Comparative Example 2)
The polycarbonate film obtained in Comparative Example 1 was uniaxially stretched at a stretching temperature of 155 ° C. to obtain a stretched film.

  The results are shown in Tables 1 and 2. In addition, the maximum draw ratio in Table 2 represents a draw ratio when the stretched film obtained in each example is broken, and the retardation value is a value in a film stretched at the maximum draw ratio.

(Example 5)
The polyester resin obtained in Example 1 was 0.4% by weight of a diimonium dye (manufactured by Nippon Kayaku Co., Ltd., “IRG-068”) and a dithiol nickel complex dye (manufactured by Midori Chemical Co., Ltd., “MIR-”). 101 ") 0.06% by weight, mixed and melt-kneaded at 220 ° C using an extruder (" GT-40-24A "manufactured by Plastic Engineering Laboratory Co., Ltd.), extruded from a T-die, and film An optical film having a thickness of 100 μm was obtained. The light transmittance of the obtained film was measured. A graph showing changes in light transmittance with respect to wavelength is shown in FIG. 1, and average transmittances in the near-infrared light region and visible light region estimated from the graph are shown in Table 3.

(Example 6)
As the dye to be dispersed, 0.4% by weight of diimmonium dye (manufactured by Nippon Kayaku Co., Ltd., “IRG-068”) and 0.04 weight by weight of phthalocyanine dye (manufactured by Nippon Shokubai Co., Ltd., “IR-14”) % Was performed in the same manner as in Example 5 except that% was used. A graph showing changes in light transmittance with respect to wavelength is shown in FIG. 2, and average transmittances in the near-infrared light region and visible light region estimated from the graph are shown in Table 3.

  As described above, the polyester resin in the examples had the same transmittance as that of the conventional resin film, and was superior in terms of refractive index, low birefringence, and stretch ratio. In addition, it was found that the polyester resin obtained in Example 1 has low birefringence, and the low birefringence can be maintained at a high level even if it is stretched. Further, even when a near-infrared absorbing pigment is dispersed in the polyester resin to produce a film, it exhibits low near-infrared light transmittance and high visible light transmittance, while maintaining transparency, the resin (or Resin film) can be provided with excellent near-infrared absorptivity.

FIG. 1 is a graph showing the light transmittance of the film obtained in Example 5. FIG. 2 is a graph showing the light transmittance of the film obtained in Example 6.

Claims (13)

An optical film composed of a polyester resin having a diol component composed of at least a 9,9-bis (hydroxyaryl) fluorene skeleton and a dicarboxylic acid component as a polymerization component,
The polyester resin is represented by the following formula (1) as a repeating unit.

[Wherein, A represents a cyclohexane residue, and Z ¹ and Z ² are the same or different and represent a phenylene group or a naphthylene group. R ^1a and R ^1b are the same or different and represent a C _2-4 alkylene group , and R ^2a and R ^2b are the same or different and are an alkyl group, an alkoxy group, an aryl group, a cycloalkyl group, an aralkyl group, a nitro group, or A cyano group, and m and n are the same or different and are integers of 1 to 5; h1 and h2 are the same or different and are integers of 0 to 2]
And a repeating unit represented by the following formula (2):

[Wherein A is the same as defined above. R ^1c represents a C _2-4 alkylene group, and q is an integer of 1 to 3.
A polyester resin having a repeating unit represented by:
The ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is the former / the latter (molar ratio) = 99/1 to 70/30,
An optical film formed by melt extrusion.
However, the resin constituting the optical film does not include a polycarbonate resin having a fluorene skeleton, and the polyester resin does not include a structural unit represented by the following two formulas as a dicarboxylic acid unit.

(However, R ⁴ in the formula represents the same or different alkyl group having 1 to 30 carbon atoms, cycloalkyl group, and aryl group, and m represents an integer of 0 to ^4. )

(However, R ⁵ in the formula represents the same or different alkyl group having 1 to 6 carbon atoms, cycloalkyl group, and aryl group, and n represents an integer of 0 to 6.) A 1,4-cyclohexane - diyl group, ^{R 1a} and ^{R 1b} is an ethylene group, the optical film of claim 1 wherein ^{R 2a} and ^{R 2b} is _{C 1-5} alkyl group. A is a 1,4-cyclohexane-diyl group, Z ¹ and Z ² are phenylene groups, R ^1a , R ^1b and R ^1c are ethylene groups, m, n and q are 1, h1 and h2 are 0, the proportion of the unit represented by the unit of the formula represented by the formula (1) (2), the former / the latter (molar ratio) = 95 / 5-80 / 20 in which claim 1 or 2. The optical film according to 2 . Photoelastic coefficient of the polyester resin, the optical film according to any one of the paragraphs 7 × ¹⁰ -12 ^cm 2 / dyn or less claims 1-3. The optical film according to any one of claims 1 to 4, wherein the polyester resin has a refractive index of 1.60 or more. The optical film according to any one of claims 1 to 5 , which has an unstretched retardation value of 10 nm or less. The optical film according to any one of claims 1 to 6, which extends lengthened. The optical film according to any one of claims 1 to 7 , which is uniaxially stretched or biaxially stretched and has a retardation value of 100 nm or less.   The optical film according to any one of claims 1 to 8, which is uniaxially stretched and has a retardation value of 50 nm or less. The optical film according to claim 1, which has a thickness of 1 to 200 μm. The optical film according to any one of claims 1 to 10 , which is used for a display. In addition, the optical film according to any one of claims 1 to 11 comprising a near infrared absorbing dye. Display member having an optical film according to any one of claims 1 to 12.

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