WO2010098111A1 - Polyester resin, and optical material, film and image display device, using same - Google Patents

Abstract

Provided is a polyester resin which has a glass transition temperature suitable for efficient formation of film by a melting process, and which exhibits a low linear thermal expansion coefficient, and excellent stretchability and transparency. Also provided are both an optical element using the polyester resin and a film using the same. The polyester resin has structures represented respectively by general formulae (1), (2), (3) and (4) [wherein R¹¹ to R¹⁴ and R²¹ to R²⁸ are each independently a hydrogen atom or a substituent; at least one of R¹¹ to R¹⁴ is a substituent; R¹⁵ to R¹⁸ are each a hydrogen atom; R³¹ and R³² are each independently a substituent; m and n are each independently an integer of 0 to 4; X is a divalent connecting group and is not a part of either ring structure; and l is a natural number].

Description

Polyester resin, and optical material, film and image display apparatus using the same

The present invention relates to a polyester resin that is easily melt-formed and has excellent transparency. The present invention also relates to an optical material or film using the polyester resin, particularly to a film having an appropriate glass transition temperature, easy to melt film formation and having a small linear thermal expansion coefficient, and an image display device using the film.

Inorganic glass materials are widely used as transparent materials because they are excellent in transparency and heat resistance and have small optical anisotropy. However, since inorganic glass is difficult to mold and has a large specific gravity and is brittle, the molded glass product is disadvantageous in that it is heavy and easily damaged. Due to such drawbacks, in recent years, development of resin materials that replace inorganic glass materials has been actively conducted.

For example, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, and the like are known as resin materials intended to replace such inorganic glass materials. Since these resin materials are lightweight, excellent in mechanical properties, and excellent in processability, they are recently used in various applications such as lenses and films.

In recent years, it has been studied to replace the display substrate from glass to resin, and in particular, a resin substrate on which ITO (indium tin oxide) can be placed is required. This is because by using a resin, various advantages such as weight reduction, impact resistance, and reduction in thickness can be obtained. In order to replace such a resin substrate with glass, a certain degree of heat resistance is required. In addition, when manufacturing a display substrate while heating the resin, especially when annealing after placing ITO on the resin, it is necessary to have a low coefficient of linear thermal expansion when formed into a film from the viewpoint of dimensional stability. It is demanded from.
On the other hand, when using a resin material for a film use, it is calculated | required that it is easy to manufacture by melt film forming from a viewpoint of manufacturing cost. Here, if the heat resistance of the resin is improved too much, a high temperature is required for melt film formation. Moreover, it is necessary to suppress the manufacturing cost required for heating even within the range where melt film formation is possible. For this reason, there is a strong demand for a resin having an appropriate glass transition temperature (hereinafter also referred to as Tg) that can be melt-formed at a practical temperature and has a low manufacturing cost for heating.
Further, when the resin material is used for a film, it needs to have high physical strength such as elongation at break and good stretchability.

In order to achieve both heat resistance and a low linear thermal expansion coefficient, a low linear thermal expansion coefficient film using a resin having a polyarylate structure of biphenol and dicarboxylic acid has been studied (see Patent Document 1). However, Patent Document 1 discloses only a solution casting method in which a resin is dissolved in a solvent and a polyester resin is produced by solution casting. In addition, in this document, an example of using an isodicarboxylic acid component such as isophthalic acid as a dicarboxylic acid component in combination with a terephthalic acid component (a combined system of terephthalic acid and isophthalic acid, or a combined system of terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid) Etc.) was not disclosed.

A resin having a polyarylate structure of biphenol and dicarboxylic acid other than Patent Document 1 is also known, but the low linear thermal expansion coefficient and melt film-forming property have not been particularly studied (for example, Patent Document 2). And 3).

JP 2007-254663 A Japanese Patent Laid-Open No. 10-017658 JP 58-180525 A

The inventors of the present invention have studied the problem of obtaining a resin that satisfies all the above required characteristics.
However, the resin described in Patent Document 1 is not satisfactory from the viewpoint of manufacturing cost. That is, although the resin described in Patent Document 1 has achieved both the heat resistance and the low linear thermal expansion coefficient of the film using the resin to some extent, the polyester resin described in the example of the same document is However, it was not satisfactory from the viewpoint of melt film formation.
In addition, when the present inventors examined a resin containing a biphenol having a specific structure described in Patent Document 2, it was certainly suitable for the interfacial polymerization method because of its good solubility in a solvent. It has been found that since the thermal expansion coefficient is too high, the dimensional stability is deteriorated during the process of laminating and annealing the polyester resin film with ITO or the like, leading to performance deterioration of the obtained image display device.
Therefore, it has been desired to develop a resin having an appropriate glass transition temperature when performing efficient melt film formation and having a low linear thermal expansion coefficient when formed into a film.

The object of the present invention is to obtain a resin satisfying all the above-mentioned characteristics. That is, the present invention relates to a polyester resin having an appropriate glass transition temperature, a low coefficient of linear thermal expansion, good stretchability and transparency when performing efficient melt film formation, and the use thereof. An object of the present invention is to provide optical parts and films. Moreover, it aims at providing the image display apparatus using this film.

As a result of intensive studies, the present inventors have found that the above-described problem can be achieved by the following configuration.

[1] A structure represented by the following general formula (1), a structure represented by the following general formula (2), a structure represented by the following general formula (3), and a structure represented by the following general formula (4) Polyester resin characterized by containing.

(In the general formula (1), R ¹¹ to R ¹⁴ each independently represents a hydrogen atom or a substituent, provided that at least one of R ¹¹ to R ¹⁴ is a substituent. R ¹⁵ to R ¹⁸ are hydrogen atoms. Represents.)

(In the general formula (2), R ²¹ to R ²⁴ each independently represents a hydrogen atom or a substituent, and l represents a natural number.)

(In the general formula (3), R ³¹ and R ³² each independently represent a substituent, m and n each independently represent an integer of 0 to 4, and X represents a divalent linking group, provided that X Is not part of the ring structure.)

(In the general formula (4), R ²⁵ to R ²⁸ each independently represents a hydrogen atom or a substituent.)
[2] The polyester resin according to [1], wherein in the general formula (1), at least one of R ¹¹ to R ¹⁴ is a halogen atom, an alkyl group, a cyano group, or an alkoxy group.
[3] The polyester resin according to [1], wherein in the general formula (1), at least one of R ¹¹ to R ¹⁴ is a chlorine atom, a methyl group, or a methoxy group.
[4] The polyester resin according to any one of [1] to [3], which satisfies the following formula (A):
a + 0.5 × c ≧ 70 (A)
(In formula (A), a is the content (unit: mol%) of the structure derived from the aromatic diol represented by the general formula (1) with respect to the structure derived from all aromatic diols contained in the polyester resin. And c represents the content (unit: mol%) of the structure derived from the dicarboxylic acid represented by the general formula (2) with respect to all the structures derived from the dicarboxylic acid contained in the polyester resin.
[5] The polyester resin according to any one of [1] to [4], which contains a structure represented by the following general formula (5).

(In the general formula (5), R ⁴¹ and R ⁴² each independently represent a substituent, and p and q each independently represents an integer of 0 to 3.)
[6] The polyester resin according to any one of [1] to [5], wherein the light transmittance at a wavelength of 400 nm is 50% or more when the polyester resin is a film having a thickness of 100 μm.
[7] The polyester resin according to any one of [1] to [6], wherein the glass transition temperature (Tg) is 170 ° C. or higher.
[8] The polyester resin according to any one of [1] to [7], wherein the glass transition temperature (Tg) is 250 ° C. or lower.
[9] Any one of [1] to [8], wherein the weight of the structure represented by the general formula (2) is greater than the weight of the structure represented by the general formula (4). The polyester resin as described in.
[10] An optical material comprising the polyester resin according to any one of [1] to [9].
[11] A film comprising the polyester resin according to any one of [1] to [9].
[12] The film according to [11], wherein the linear thermal expansion coefficient is 40 ppm / K or less.
[13] The film according to [11] or [12], wherein a gas barrier layer is provided.
[14] The film according to any one of [11] to [13], wherein a transparent conductive layer is provided.
[15] An image display device comprising at least one film according to any one of [11] to [14].

According to the present invention, a polyester resin having an appropriate glass transition temperature, a low coefficient of linear thermal expansion, good stretchability and transparency when performing efficient melt film formation, and use thereof It is possible to provide an optical component, a film, and an image display device using the film. The polyester resin of the present invention also has sufficient heat resistance when manufacturing a display substrate, particularly when annealing is performed by placing ITO on the resin. Furthermore, the polyester resin of the present invention has excellent transparency during molding, and can be suitably used for optical parts, films and image display devices.

Hereinafter, the polyester resin, film and image display device 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.

[Polyester resin]
The polyester resin of the present invention (hereinafter also referred to as the resin of the present invention) is represented by the structure represented by the following general formula (1), the structure represented by the following general formula (2), and the following general formula (3). And a structure represented by the following general formula (4). Hereinafter, the characteristics of the resin of the present invention will be described in order from the general formula (1).

(Structure represented by general formula (1))
The polyester resin of the present invention contains a structure represented by the following general formula (1). The polyester resin of the present invention contains the structure represented by the general formula (1) simultaneously with the structure represented by the general formula (3) and the structure represented by the general formula (4). It is possible to achieve both melt film-forming properties and a low linear thermal expansion coefficient.

In the general formula (1), R ¹¹ to R ¹⁴ each independently represents a hydrogen atom or a substituent. However, at least one of R ¹¹ to R ¹⁴ is a substituent. R ¹⁵ to R ¹⁸ represent a hydrogen atom.
In the polyester resin of the present invention, since at least one of R ¹¹ to R ¹⁴ is a substituent, the polyester resin of the present invention can be melted without being heated to a high temperature and is soluble in a solvent such as dichloromethane. It is also preferable from the viewpoint.
In the general formula (1), preferred substituents represented by R ¹¹ to R ¹⁴ are alkyl groups (preferably having 1 to 10 carbon atoms, such as methyl group, ethyl group, isopropyl group, tert-butyl group, etc. ), Halogen atoms (for example, chlorine atom, bromine atom, iodine atom and the like), aryl groups (preferably having 6 to 20 carbon atoms, for example, phenyl group, biphenyl group, naphthyl group and the like), alkoxy groups (having 1 to 10 carbon atoms). For example, a methoxy group, an ethoxy group, an isopropoxy group, etc.), an acyl group (preferably having 2 to 10 carbon atoms, for example, an acetyl group, a propionyl group, a butyryl group, etc.), an acylamino group (having 1 to 10 carbon atoms). Preferably, for example, a formylamino group, an acetylamino group, etc.), a nitro group, a cyano group, and a combination of these . More preferably an alkyl group, a halogen atom, an aryl group, an alkoxy group, a cyano group, or a nitro group, and particularly preferably at least one of the R ¹¹ to R ¹⁴ is a halogen atom, an alkyl group, a cyano group, or an alkoxy group, More particularly preferred is a chlorine atom, a methyl group or a methoxy group. A methyl group and a chlorine atom are preferable from the viewpoint of compatibility between solubility, meltability and heat resistance, and linear thermal expansion coefficient.
In the general formula (1), it is preferable that two of R ¹¹ to R ¹⁴ are substituents, and the remaining two are hydrogen atoms. In this case, the positions of the two substituents are preferably two positions R ¹¹ and R ¹⁴ or two positions R ¹² and R ¹³ .

Specific examples of general formula (1) are shown below, but the structure represented by general formula (1) that can be used in the present invention is not limited to these.

(Structure represented by general formula (2))
The polyester resin of the present invention contains a structure represented by the general formula (2).

In the general formula (2), R ²¹ to R ²⁴ each independently represents a hydrogen atom or a substituent, and l represents a natural number. Preferred substituents for R ²¹ to R ^{24 are the same} as the preferred substituents represented by R ¹¹ to R ¹⁸ . R ²¹ to R ²⁴ are particularly preferably hydrogen atoms.

The l is preferably 1 to 3, and more preferably 1 to 2. When the l is 3 or less, the solubility and the melt production are good, and the film transparency is also good. When l is 2, it represents a biphenyl structure, and when l is 3, it represents a terphenyl structure. When l is 2 or more, the plurality of R ²¹ to R ²⁴ each independently represents a hydrogen atom or a substituent.

(Structure represented by the general formula (3))
The polyester resin of the present invention contains a structure represented by the general formula (3). The polyester resin of the present invention has a structure represented by the general formula (3) which is a structure that can be bent relatively in addition to the components of the linear structure represented by the general formulas (1) and (2). By having a bending component), the film-forming property and the low linear thermal expansion coefficient are compatible, and the stretchability is also good.

In the general formula (3), R ³¹ and R ³² each independently represent a substituent, m and n each independently represent an integer of 0 to 4, and X represents a divalent linking group. However, X is not part of the ring structure.
Preferable R ³¹ and R ³² in the general formula (3) are an alkyl group (preferably having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group), a halogen atom (for example, A chlorine atom, a bromine atom, an iodine atom, etc.), an aryl group (preferably having 6 to 20 carbon atoms, for example, a phenyl group, a biphenyl group, a naphthyl group, etc.), an alkoxy group (preferably having 1 to 10 carbon atoms, for example, a methoxy group) , Ethoxy group, isopropoxy group and the like), acyl group (preferably having 2 to 10 carbon atoms, for example, acetyl group, propionyl group, butyryl group and the like), acylamino group (preferably having 1 to 10 carbon atoms, for example, formylamino group) And acetylamino group), nitro group, cyano group and the like. More preferred are an alkyl group, a halogen atom, an aryl group, an alkoxy group, and a nitro group, and particularly preferred are an alkyl group and a halogen atom. The above 4 is preferable, 0 to 2 is more preferable, and 0 to 1 is particularly preferable. N is preferably 0 to 4, more preferably 0 to 2, and particularly preferably 0 to 1.

In general formula (3), X represents a divalent linking group. Examples of X include an alkylene group, an alkylidene group, a perfluoroalkylidene group, an oxygen atom, a sulfur atom, a ketone group, a sulfonyl group, and —NR′— (R ′ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). -CO-NH- are preferable, and an alkylidene group, an oxygen atom, a sulfur atom, a ketone group, an amino group, and a sulfonyl group are preferable, and isopropylidene and an oxygen atom are particularly preferable. However, X is not part of the ring structure. Here, not being a part of the ring structure means that X itself is not a linking group containing a ring, and X is one of benzene rings connected to both sides of X in formula (3) and / or It means that X does not form a fused ring with R ³¹ and / or R ³² without creating a fused ring with both.
X is preferably a substituted or unsubstituted carbon atom, oxygen atom or sulfur atom, more preferably a substituted or unsubstituted carbon atom, and particularly preferably an alkyl group-substituted carbon atom. Preferably, it is a dimethyl-substituted carbon atom, and more particularly preferred.

In general formula (3), the bonding position of the two oxygen atom linking groups may be anywhere on the benzene ring. Among them, the bonding positions of the two oxygen atom linking groups are preferably the 4th and 4 'positions of the benzene ring.

Specific examples (3-1) to (3-22) of the structure represented by the general formula (3) are shown below, but the structure represented by the general formula (3) that can be used in the present invention includes these. It is not limited.

(Structure represented by formula (4))
The polyester resin of the present invention contains a structure represented by the general formula (4).

(In the general formula (4), R ²⁵ to R ²⁸ each independently represents a hydrogen atom or a substituent.)

In the general formula (4), R ²⁵ to R ²⁸ each independently represents a hydrogen atom or a substituent.
The preferred substituents represented by R ²⁵ to R ²⁸ are the same as the preferred substituents represented by R ¹¹ to R ¹⁸ .

(Other structures)
The resin of the present invention contains an ester bond in the main chain. In addition to the ester bond, the resin of the present invention may contain one or more of an ether bond, a carbonate bond, a sulfone bond, a ketone bond, an imide bond, an amide bond, a urethane bond, and a urea bond. .

The polyester resin of the present invention preferably contains a structure represented by the following general formula (5) from the viewpoint of finely adjusting in the direction of increasing Tg and improving the melt film forming property.

(In the general formula (5), R ⁴¹ and R ⁴² each independently represent a substituent, and p and q each independently represents an integer of 0 to 3.)

In addition, as a preferable substituent in the general formula (5), an alkyl group (preferably having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group), a halogen atom (for example, chlorine) Atoms, bromine atoms, iodine atoms, etc.), aryl groups (preferably having 6 to 20 carbon atoms, such as phenyl group, biphenyl group, naphthyl group, etc.), alkoxy groups (preferably having 1 to 10 carbon atoms, such as methoxy group, Ethoxy group, isopropoxy group and the like), acyl group (preferably having 2 to 10 carbon atoms, such as acetyl group, propionyl group and butyryl group), acylamino group (preferably having 1 to 10 carbon atoms, such as formylamino group, Acetylamino group), nitro group, cyano group and the like. More preferred are an alkyl group, a halogen atom, an aryl group, an alkoxy group, and a nitro group, and particularly preferred are an alkyl group and a halogen atom.

In the general formula (5), the position at which the carbonyl group is linked may be any carbon of the naphthalene ring, and two carbonyl groups may be linked to one ring. The carbonyl group is preferably bonded at the 2nd or 3rd position and preferably at the 6th or 7th position, and more preferably at the 2nd or 6th position.
P and q each independently represents an integer of 0 to 3, p is preferably an integer of 0 to 2, and q is preferably an integer of 0 to 2.

Specific examples of the structure represented by the general formula (5) are shown below, but the structure represented by the general formula (5) that can be used in the present invention is not limited to these.

(Ratio of each structure in the resin)
The polyester resin of the present invention preferably satisfies the following formula (A) from the viewpoint of reducing the linear thermal expansion coefficient.
a + 0.5 × c ≧ 70 (A)
(In formula (A), a is the content (unit: mol%) of the structure derived from the aromatic diol represented by the general formula (1) with respect to the structure derived from all aromatic diols contained in the polyester resin. And c represents the content (unit: mol%) of the structure derived from the dicarboxylic acid represented by the general formula (2) with respect to all the structures derived from the dicarboxylic acid contained in the polyester resin.
In the present specification, the structure derived from the aromatic diol includes, for example, a structure represented by the general formula (1), a structure represented by the general formula (3), and the like.
In the present specification, the structure derived from the dicarboxylic acid is, for example, a structure represented by the general formula (2), a structure represented by the general formula (4), and a structure represented by the general formula (5). Etc.
Hereinafter, the left side of the formula (A), that is, the value of a + 0.5 × c is also referred to as a linear component amount.
Here, the coefficients of a and c in the formula (A) of the linear component amount are specifically set to coefficients of 1 and 0.5, respectively, assuming that there is a linear component of 0.5 per phenylene group. Were determined. The mathematical meaning of the linear component amount formula (A) is related to the linear thermal expansion coefficient of a film obtained by uniaxial stretching.
The linear component amount, that is, the value on the left side of the formula (A) is more preferably 80 to 120, and particularly preferably 90 to 120.

In the polyester resin of the present invention, the weight of the structure represented by the general formula (2) is preferably larger than the weight of the structure represented by the general formula (4).
The weight ratio of the structure represented by the general formula (2) and the structure represented by the general formula (4) is preferably 55:45 to 85:15, and 55:45 to 75:25. More preferably, it is particularly preferably 60:40 to 75:25. It is preferable that the weight ratio of the structure represented by the general formula (2) and the structure represented by the general formula (4) is 55:45 to 85:15 because the linear thermal expansion coefficient is low.
In particular, if the weight ratio of the structure represented by the general formula (2) and the structure represented by the general formula (4) is 55:45 or more, the linear thermal expansion coefficient is preferably small, and the weight ratio is 85:15 or less. If so, the melting temperature does not become excessively high, melting becomes easy, and the film obtained after melting is less likely to become cloudy, which is preferable.

On the other hand, when the weight of the structure represented by the general formula (2) is equal to or smaller than the weight of the structure represented by the general formula (4), the polyester resin of the present invention is represented by the general formula (1). The one where the content rate of the structure represented is high is preferable.
In particular, when the content a (unit: mol%) of the phenol-derived structure represented by the general formula (1) with respect to all the phenol-derived structures contained in the polyester resin is 45 (c is 50), When a + 0.5c is 45 or more and 70% or more), the weight of the structure represented by the general formula (2) is equal to the weight of the structure represented by the general formula (4). Even if it is equal or small, the effect of the present invention can be sufficiently achieved. Further, the a is more preferably 45 to 90 mol%, and particularly preferably 50 to 85 mol%.
When the molar ratio (substance ratio) of the structure represented by the general formula (1) described later and the structure represented by the general formula (3) is 0.70: 0.30 or more, Even if the content of the structure represented by the general formula (2) is equal to or smaller than the content of the structure represented by the general formula (4), the effects of the present invention can be sufficiently achieved.

The polyester resin of the present invention has a content A (unit: mol%) of the structure represented by the general formula (1) and a content B (unit: mol%) of the structure represented by the general formula (3). ) Preferably satisfies A / B> 1.5 from the viewpoint of reducing the linear thermal expansion coefficient.
In particular, when X is a dimethyl-substituted carbon atom, it is preferable that A / B> 1.5 because the linear thermal expansion coefficient can be remarkably lowered.
The lower limit value of A / B is more preferably 1.55 or more, further preferably 1.6 or more, particularly preferably 1.85 or more, and particularly preferably 2.33 or more. Preferably, it is even more particularly preferable that it is 2.5 or more.
When these values are expressed as ratios, the molar ratio (substance ratio) of the structure represented by the general formula (1) and the structure represented by the general formula (3) is 0.60: 0. It is preferably more than 40, more preferably 0.607: 0.393 or more, further preferably 0.615: 0.385 or more, and particularly preferably 0.65: 0.35 or more. Preferably, it is more preferably 0.70: 0.30 or more, and even more preferably 0.75: 0.25 or more.

In the resin of the present invention, the content of the structure represented by the general formula (1) is preferably 10 to 99 mol%, more preferably 20 to 90 mol%, and particularly preferably 30 to 85 mol%.
In the resin of the present invention, the content of the structure represented by the general formula (2) is preferably 20 to 99 mol%, more preferably 30 to 95 mol%, and particularly preferably 40 to 95 mol%.
In the resin of the present invention, the content of the structure represented by the general formula (3) is preferably 1 to 80 mol%, more preferably 10 to 70 mol%, and particularly preferably 15 to 65 mol%.
In the resin of the present invention, the content of the structure represented by the general formula (4) is preferably 1 to 80 mol%, more preferably 5 to 70 mol%, and particularly preferably 5 to 65 mol%.
In the resin of the present invention, the content of the structure represented by the general formula (5) is preferably 0 to 90 mol%, more preferably 0 to 70 mol%, and particularly preferably 1 to 50 mol%.

(Production method of resin)
The resin of the present invention can be synthesized generally using a biphenol derivative, dicarboxylic acid and / or a derivative thereof as a monomer. Further, it may be synthesized as a copolymer using a bisphenol derivative or the like.
As a general synthesis method of a biphenol derivative having a substituent, mention is made of the method described in Macromolecules, 1996, 29, pages 3727-3735, Journal of Textile Chemistry, Vol. 84, No. 2 (1963), pages 143-145. Can do.
The dicarboxylic acid derivative can be synthesized by a method similar to the method of introducing a substituent into dialkylnaphthalene and oxidizing the alkyl group. General methods for introducing substituents into dialkylnaphthalenes include Journal of Organic Chemistry, 2003, 68 (22), 8373-8378; Hetreroatom Chemistry, 2001, 12 (4), pages 287-292; Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry, 1981, (3) 746-750; Journal of the Chemical Society [Section] D: Chemical Communications, (24), 1487, 1969 Can be mentioned.
Examples of a general method for oxidizing an alkyl group substituted with naphthalene include the method described in Journal of organic Chemistry, 50 (22), pages 4211-4218, 1985.
As a general method for synthesizing polyarylate using the above-mentioned monomers, there can be mentioned the methods described in New Polymer Experimental Science 3, Polymer Synthesis / Reaction (2), Kyoritsu Shuppan (Items 87 to 95).
Moreover, there is no restriction | limiting in particular about the order which adds each monomer component at the time of a synthesis | combination, Even if it adds all the monomer components simultaneously, only diphenolic acid derivative may be polymerized after polymerizing only biphenol and bisphenol first. .

(Specific examples of resin)
Specific examples (P-1 to P-18) of the polyester resin of the present invention are shown below, but the polyester resin that can be used in the present invention is not limited thereto. In P-1 to P-18, the numbers on the lower right of the parenthesis represent the mol% of each structure in the polyester resin.

(Resin characteristics)
The weight average molecular weight of the resin of the present invention is preferably 10,000 to 5,000,000, more preferably 15,000 to 1,000,000, and particularly preferably 20,000 to 500,000.

The resin of the present invention is a copolymer, and the polymerization form may be random copolymerization, block copolymerization, or other polymerization forms.

The glass transition temperature (Tg) of the resin of the present invention is preferably in a range suitable for melt film formation. Specifically, the temperature is preferably 170 ° C. or higher, more preferably 250 ° C. or lower, particularly preferably 180 ° C. to 250 ° C., and particularly preferably 195 ° C. to 250 ° C. The transparency of the film obtained can be improved more because Tg of resin of this invention is said range. Further, when Tg is 170 ° C. or higher, the dimensional stability during the process of laminating with ITO using the resin of the present invention as an optical film (process involving heating) is enhanced, and the image display of the present invention is performed. The performance of the device can be increased.

The resin of the present invention is useful for, for example, optical materials and films of the present invention described later. As the optical material, for example, an optical film such as a polarizing plate protective film, a retardation film, an antireflection film, an electromagnetic wave shielding film, a pickup lens, a microlens array, a light guide plate, an optical fiber, an optical waveguide and the like can be preferably exemplified.

[the film]
(Film production method)
The resin of the present invention can be preferably used as a film. As a method for producing the film of the present invention, a solution casting method and an extrusion molding method (melt molding method) are preferably used, and an extrusion molding method is more preferably used.
Regarding the casting and drying methods in the solution casting method, U.S. Pat. No. 2,336,310, U.S. Pat. No. 2,367,603, U.S. Pat. No. 2,429,078, U.S. Pat. No. 2,429,297, U.S. Pat. Specification, U.S. Pat. No. 2,607,704, U.S. Pat. No. 2,739,069, U.S. Pat. No. 2,739,070, British Patent 6,407,731, British Patent 7,368,92, Japanese Patent Publication No. 45-4554 JP-B-49-5614, JP-A-60-176834, JP-A-60-203430, JP-A-62-115035.

As the extrusion molding method, a known method in this field can be adopted, and there is no particular limitation.

As the manufacturing apparatus for manufacturing the film of the present invention using the extrusion molding method, a known manufacturing apparatus in this field can be employed. However, the manufacturing apparatus that can be used in the present invention is not limited to these.

Although there is no restriction | limiting in particular in the said extrusion method, It is preferable to shape | mold the resin composition containing the resin of this invention once into a pellet form before film forming. In the case of molding into a pallet shape, it is preferable that the resin composition is first melt-kneaded with a kneader, taken out in a noodle shape and then cut to prepare a pellet-shaped resin composition.
In addition to the resin of the present invention described above, the resin composition may contain a stabilizer such as an anti-coloring agent and other additives that do not contradict the spirit of the present invention.
The melt kneading temperature is preferably 250 ° C. to 350 ° C., more preferably 260 ° C. to 350 ° C., and particularly preferably 270 ° C. to 340 ° C.

Next, the pellet-shaped resin composition is introduced into a melt extruder, the resin composition is supplied to a die installed at the outlet of the melt extruder, the resin composition is melt-extruded from the die, and cast. It is preferable to produce a film by extruding and peeling off on a roll.
There is no restriction | limiting in particular as said melt extruder, A well-known melt extruder can be used, For example, a melt extruder can be used. Among these, a biaxial extruder is preferable. There is no restriction | limiting in particular in the shape of the said die, A well-known die | dye can be used, A T die, a hanger coat die, etc. can be used, It is preferable to use a hanger coat die.
The temperature of the resin composition in the melt extruder is preferably 250 ° C. to 350 ° C., more preferably 260 ° C. to 350 ° C., and particularly preferably 270 ° C. to 340 ° C.
The time for melt kneading is not particularly limited.

The cast roll is not particularly limited, and a known cast roll can be used. The temperature of the cast roll is not particularly limited.

The film of the present invention can be stretched. As the stretching method, known methods can be used. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284211, JP-A-4-298310, JP-A-11-48271. The film can be stretched by a roll uniaxial stretching method, a tenter uniaxial stretching method, a simultaneous biaxial stretching method, a sequential biaxial stretching method, an inflation method, or a rolling method described in a publication. Hereinafter, a stretching method using a tenter will be described as an example.

The film is stretched at room temperature or under heating conditions. The film may be stretched uniaxially or biaxially, but biaxial stretching is preferred. The film can be stretched by a treatment during drying, and is particularly effective when the solvent remains. For example, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film peeling speed. The film can also be stretched by conveying the film while holding it with a tenter and gradually widening the width of the tenter. Further, after the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine). The stretching ratio of the film (ratio of increase due to stretching relative to the original length) is preferably 0.5 to 300%, more preferably 1 to 200%, and particularly 1 to 100%. Is preferred.

The stretching speed is preferably 5% / min to 1000% / min, more preferably 10% / min to 500% / min. The stretching is preferably performed by a heat roll or / and 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.

The stretching temperature is preferably (Tg-100 ° C) to (Tg + 25 ° C), more preferably (Tg-80 ° C) to (Tg + 20 ° C), based on the glass transition temperature of the resin of the present invention, and (Tg-70 ° C). ) To (Tg + 15 ° C.) are particularly preferable.

The film of the present invention may be heat-treated after stretching. The heat treatment temperature is preferably (Tg-100 ° C.) to (Tg + 25 ° C.), more preferably (Tg−80 ° C.) to (Tg + 20 ° C.), and (Tg−70 ° C.) to (Tg + 15) based on the glass transition temperature Tg. C) is particularly preferred. By performing heat treatment, shrinkage stress due to stretching can be relieved and shrinkage during heating can be reduced.

(Film physical properties)
Moreover, it is preferable that the change of the length measured by the thermomechanical analysis shows the maximum point in the film of this invention in the temperature more than a glass transition temperature (Tg). Here, the thermomechanical analysis means an analysis method described in JIS K7197, which is a JIS standard. Further, that the change in length measured by thermomechanical analysis shows a maximum point means the behavior when the length contracts, expands, and further contracts.

The film of the present invention preferably has a light transmittance of 400 nm at a film thickness in terms of 100 μm of 50% or more. When the light transmittance is in the above range, there is an advantage that what is in close contact with the film can be seen through. The light transmittance is more preferably from 70 to 100%, further preferably from 75 to 100%, particularly preferably from 80 to 100%.

In addition, the film of the present invention has a coefficient of linear thermal expansion (CTE) of preferably 40 ppm / K or less, more preferably 30 ppm / K or less, and 20 ppm / K or less in any part of the plane. It is particularly preferred. When CTE is 40 ppm / K or less, when an inorganic thin film is laminated | stacked on a film, there exists an advantage that the generation | occurrence | production of the crack by the difference in an expansion coefficient at the time of a heating, and the curvature of a film can be suppressed.

The linear thermal expansion coefficient referred to in the present invention is a value in a temperature range from 25 ° C. to (Tg-30) ° C.

The linear thermal expansion coefficient of the film of the present invention is preferably the above value, and is preferably the above value in both the temperature rising process and the temperature falling process. Further, the difference between the CTE in the temperature raising process and the CTE in the temperature lowering process is preferably 20 ppm / K or less, more preferably 10 ppm / K or less, and particularly preferably 5 ppm / K or less. Since the difference between the CTE in the temperature raising process and the CTE in the temperature lowering process is 20 ppm / K or less, there is an advantage that the deformation amount before and after the heat treatment for raising and lowering the temperature is reduced.

(Functional layer)
Other layers may be formed on the film surface of the present invention depending on the application. Further, for the purpose of improving the adhesion to other parts, the film surface may be subjected to treatment such as saponification, corona treatment, flame treatment, glow discharge treatment and the like. Further, an anchor layer may be provided on the film surface.

-Gas barrier layer-
In the film of the present invention, a gas barrier layer can be laminated on at least one surface in order to suppress gas permeability. As a preferable gas barrier layer, for example, a metal oxide mainly composed of one or more metals selected from the group consisting of silicon, aluminum, magnesium, zinc, zirconium, titanium, yttrium and tantalum, silicon, aluminum, Mention may be made of films formed of metal nitrides of boron or mixtures 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, etc. A film formed of a metal oxide is good. The gas barrier layer made of these inorganic compounds is formed by vapor deposition such as sputtering, vacuum deposition, ion plating, plasma CVD, Cat-CVD, etc., by depositing a material from the vapor phase to form a film. Can be made. Of these, the sputtering method and the Cat-CVD method, which can provide particularly excellent gas barrier properties, are preferable. The temperature may be raised to 50 to 250 ° C. while the gas barrier layer is provided.

The thickness of the gas barrier layer is preferably 10 to 300 nm, and more preferably 30 to 200 nm.

The gas barrier layer may be provided on the same side or the opposite side to the transparent conductive layer described later.

The gas barrier performance of the film of the present invention is preferably 0 to 5 g / m ² · day, more preferably 0 to 3 g / m ² · day, measured at 40 ° C. and 90% relative humidity. Preferably, it is 0 to 2 g / m ² · day. The oxygen permeability measured at 40 ° C. and relative humidity 90% is preferably 0 to 1 ml / m ² · day · atm (0 to 1 × 10 ⁵ ml / m ² · day · Pa). -0.7 ml / m ² · day · atm (0 to 0.7 × 10 ⁵ ml / m ² · day · Pa) is more preferable, and 0 to 0.5 ml / m ² · day · atm (0 More preferably, it is ˜0.5 × 10 ⁵ ml / m ² · day · Pa). If the gas barrier performance is within the above range, for example, when used in an organic EL display device or a liquid crystal display device, it is preferable that deterioration of the EL element due to water vapor and oxygen can be substantially eliminated.

For the purpose of improving the gas barrier performance, it is preferable to form a defect compensation layer adjacent to the gas barrier layer. Examples of the defect compensation layer include (1) an inorganic oxide layer prepared by using a sol-gel method as described in US Pat. No. 6,171,663 and JP-A-2003-94572, and (2) US Pat. The organic material layer described in the specification can be used. These defect compensation layers can be prepared by vapor deposition under vacuum and then curing with ultraviolet rays or electron beams, or by applying and then curing with heating, electron beams, ultraviolet rays or the like. When the defect compensation layer is produced by a coating method, various conventional coating methods such as spray coating, spin coating, and bar coating can be used.

The film of the present invention may be provided with an inorganic barrier layer, an organic barrier layer, an organic-inorganic hybrid barrier layer, etc. for the purpose of imparting chemical resistance.

-Transparent conductive layer-
A transparent conductive layer may be laminated on at least one side of the film of the present invention. A known metal film, metal oxide film, or the like can be applied as the transparent conductive layer. Among these, a metal oxide film having excellent transparency, conductivity, and mechanical properties is preferably used as the transparent conductive layer. The metal oxide film is, for example, a metal oxide film of indium oxide, cadmium oxide or tin oxide to which tin, tellurium, cadmium, molybdenum, tungsten, fluorine, zinc, germanium or the like is added as an impurity; an oxide to which aluminum is added as an impurity Examples thereof include metal oxide films such as zinc and titanium oxide. 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, a vapor deposition method that forms a film by depositing a material from the vapor phase, such as a sputtering method, a vacuum evaporation method, an ion plating method, a plasma CVD method, and a Cat-CVD method, is suitable. The film can be formed by the methods described in Japanese Patent Laid-Open Nos. 2002-322561 and 2002-361774. Among these, the sputtering method is preferable from the viewpoint that particularly excellent conductivity and transparency can be obtained.

The preferred degree of vacuum of the sputtering method, vacuum deposition method, ion plating method, or plasma CVD method is 0.133 mPa to 6.65 Pa, preferably 0.665 mPa to 1.33 Pa. Before forming the transparent conductive layer, it is preferable to subject the base film to a surface treatment such as plasma treatment (reverse sputtering) or corona treatment. The temperature may be raised to 50 to 200 ° C. while the transparent conductive layer is provided.

The film thickness of the transparent conductive layer thus obtained is preferably 20 to 500 nm, more preferably 50 to 300 nm.

The surface electrical resistance of the transparent conductive layer measured at 25 ° C. and 60% relative humidity is preferably 0.1 to 200 Ω / □, more preferably 0.1 to 100 Ω / □. More preferably, it is 0.5 to 60Ω / □. Moreover, the light transmittance of the transparent conductive layer is preferably 80% or more, more preferably 83% or more, and further preferably 85% or more.

[Image display device]
The film of the present invention described above can be used for an image display device. Here, the type of the image display device is not particularly limited, and conventionally known ones can be exemplified. Moreover, the flat panel display excellent in display quality can be produced using the film of this invention as a board | substrate. Examples of the flat panel display include a liquid crystal display device, a plasma display, organic electroluminescence (EL), inorganic electroluminescence, a fluorescent display tube, a light emitting diode, and a field emission type. Besides these, a conventional glass substrate has been used. It can be used as a substrate instead of a display-type glass substrate. Furthermore, the film of the present invention can be applied to uses such as solar cells and touch panels in addition to flat panel displays. The touch panel can be applied to, for example, those described in JP-A-5-127822 and JP-A-2002-48913.

Further, a thin film transistor TFT can be produced on the film of the present invention. The TFT can be manufactured by a known method disclosed in Japanese Patent Application Laid-Open No. 11-102867, Japanese Patent Application Laid-Open No. 10-512104, and Japanese Patent Application Laid-Open No. 2001-68681. Further, these substrates may have a color filter for color display. The color filter may be manufactured using any method, but is preferably manufactured using a photolithography technique.

The TFT produced in the present invention may be an amorphous silicon TFT or a polycrystalline silicon TFT. An annealing method by laser irradiation is preferably used for polycrystallizing amorphous silicon.

Examples of the method for forming silicon of the semiconductor layer of the TFT include a sputtering method, a plasma CVD method, an ICP-CVD method, and a Cat-CVD method, but the sputtering method is preferable. By manufacturing by a sputtering method, the hydrogen concentration in the silicon thin film can be reduced, and peeling of the silicon layer due to laser irradiation for polycrystallization can be prevented.

An intrinsic silicon thin film, an impurity silicon thin film, a silicon nitride thin film, a silicon oxide thin film and the like necessary for TFT production can be formed on the film of the present invention by plasma CVD, but the substrate temperature at that time is preferably 250 ° C. or lower. .

The pixel electrode can be made of ITO or IZO by sputtering. The heat treatment temperature for lowering the resistivity is preferably 250 ° C. or lower.

The structure of the TFT manufactured in the present invention may be any structure such as a channel etching type, an etching stopper type, a top gate type, and a bottom gate type.

In the case of using the film of the present invention as a substrate for a liquid crystal display device or the like, the resin composition constituting the film is preferably an amorphous polymer in order to achieve optical uniformity. Furthermore, for the purpose of controlling retardation (Re) and its wavelength dispersion, resins having different signs of intrinsic birefringence can be combined, or resins having a large (or small) wavelength dispersion can be combined.

The film of the present invention is preferably laminated by combining different resin compositions from the viewpoint of controlling retardation (Re) and improving gas permeability and mechanical properties. A preferred combination of different resin compositions is not particularly limited, and any of the above-described resin compositions can be used.

A reflective liquid crystal display device generally has a configuration 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. . Among these, the film of the present invention can be used as a transparent electrode and / or an upper substrate. In the case of color display, it is preferable to further form 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 It generally has a configuration of a polarizing film. Among these, the film of the present invention can be used as an upper transparent electrode and / or an upper substrate. 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.

The type of liquid crystal layer (liquid crystal cell) is not particularly limited, but TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-ferroelectric Liquid Crystal), OCB (Optically Compensated Bend) Various display modes such as STN (Super Twisted Nematic), 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 film of the present invention is also effective for use in a display mode liquid crystal display device. In addition, the present invention is effective when used for any of a transmissive, reflective, and transflective liquid crystal display device.

As for the liquid crystal cell and the liquid crystal display device, 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 (AsiaＡDisplay 98, Proc.of the-18th -Inter. Display res. 予 Conf. (Preliminary Book) (1998) 383), Para-A (LCD / PDP International 99), DDVA (SID 98, ｇ Digest of tech. Papers (Preliminary Book) 29 (1998) 838), EOC (SID98, Digest of tech. Papers (Proceedings) 29 (1998) 319), PSHA (SID98, ｉDigest of tech. Papers (Proceedings) 29 (1998) 10 1), RFFMH (Asia Display 98, Proc. Of the-18th-Inter. Displays. Conf. (Preliminary Collection) (1998) 375), HMD (SID98, Diest of tech. Paper ２９ (98) 29) ), JP-A-10-123478, WO98 / 48320, pamphlet 30302477, WO00 / 65384, and the like.

The film of the present invention can be suitably used for organic EL display applications. The specific layer structure of the organic EL display device includes 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 injection Examples include layer / transparent cathode.

In the organic EL display device in which the film of the present invention can be used, a direct current (which may include an alternating current component if necessary) voltage (usually 2 to 40 V) or a direct current is applied between the anode and the cathode. Thus, light emission can be obtained. Regarding the driving of these light emitting elements, for example, JP-A-2-148687, JP-A-6-301355, JP-A-5-290080, JP-A-7-134558, JP-A-8-234658, and JP-A-8-2441047. US Pat. Nos. 5,828,429 and 6023308, Japanese Patent No. 2784615, and the like can be used.

As a full color display method of the organic EL display device, any method such as a color filter method, a three-color independent light emission method, a color conversion method may be used.

The liquid crystal display measures and the driving method of the organic EL display device may be either passive matrix or active matrix.

The film of the present invention is an optical film, retardation film, polarizing plate protective film, transparent conductive film, substrate for display device, substrate for flexible display, substrate for flat panel display, substrate for solar cell, substrate for touch panel, for flexible circuit It can be used for a substrate, an optical disk protective film and the like.

Hereinafter, the features of the present invention will be described more specifically with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples 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.

(Polymer synthesis)
-Synthesis of Exemplified Compound P-1-
In a 300 ml three-necked flask equipped with a stirrer, 15.3 g of 2,2′-dimethyl-4,4′-bishydroxybiphenyl, 7.0 g of bisphenol A, 360 mg of hydrosulfite sodium, tetra-n-butylammonium 1600 mg of chloride, 390 ml of methylene chloride and 450 ml of distilled water were added and dissolved by stirring under a nitrogen stream. A solution prepared by dissolving 10.36 g of terephthalic acid chloride and 10.36 g of isophthalic acid chloride in 180 ml of methylene chloride was added to the solution.

Further, a mixture of 107 ml of 2 mol / L sodium hydroxide aqueous solution and 9 ml of water was added dropwise at 15 to 20 ° C. over 1 hour. After stirring for 3 hours after completion of the dropwise addition, the reaction solution was transferred to a 3-liter three-necked flask, and 1.8 ml of acetic acid and 1800 ml of ethyl acetate were slowly added. The obtained polymer powder was collected by filtration, washed successively with 1 L of ethyl acetate, 1 L of water, and 1 L of methanol and dried to obtain 32 g of the above exemplified compound P-1.

As a result of measurement by GPC (THF solvent: polystyrene conversion (manufactured by Tosoh Corporation, HLC-8120GPC)), the weight average molecular weight was 100000. The obtained polymer was dissolved in methylene chloride and cast on a glass plate. Thereafter, the glass transition temperature of the film having a thickness of 100 μm obtained by drying was measured using TMA8310 (manufactured by Rigaku Denki Co., Ltd., ThermoＴPlus series), and found to be 219 ° C.

-Synthesis of Exemplified Compounds P-2, P-7, P-9, P-10, P-12 to P-17, Comparative Polymers 1 and 3 to 5-
Except for changing the weights of the components used, the above-described exemplary compound and a comparative polymer having the structure described below were obtained in the same manner as in the synthesis of exemplary compound P-1. The glass transition temperature of each obtained polyester resin was the value described in Table 1 below.

-Synthesis of Comparative Polymer 2-
As a comparative polymer 2, a polymer described in Example 5 of JP-A-10-17658 having the following structure was synthesized.

[Production of film]
[Example 1]
(Production, stretching and heat treatment)
Exemplified compound P-1 was kneaded for 10 minutes using a small amount kneader set at 350 ° C. (product name: MiniLab, manufactured by Haake), taken out in a noodle form, cut with nippers, and a pellet-shaped resin composition was obtained. It was.
The pellet-shaped resin composition prepared above was melt-extruded from a hanger die using a biaxial melt extruder adjusted from 280 ° C. (inlet temperature) to 330 ° C. (outlet temperature), and this was set to 120 ° C. The film was produced by extruding and peeling onto a cast roll.
The film was cut into a size of 120 mm × 120 mm and stretched by a simultaneous biaxial stretching machine. The first stage stretching conditions were a chuck distance of 100 mm (both longitudinal and lateral), a resin temperature of 210 ° C., a stretching speed of 100 mm / min, and a stretching distance of 40 mm (both longitudinal and lateral). After stretching, while being held in a biaxial stretching machine, it was heated to 210 ° C. and heat-treated until the stress became substantially constant. Thereafter, the film temperature was cooled to 100 ° C. or lower and taken out from the biaxial stretching machine. The stretched film was set in a 120 mm square inner metal frame and heat-treated in a nitrogen atmosphere at 200 ° C. for 24 hours, to obtain a stretched film of Example 1. The draw ratio was 5% to 10% before the breaking elongation.

[Examples 2 to 12, Comparative Examples 1 to 5]
Except for using Exemplified Compounds P-2, P-7, P-9, P-10, P-12 to P-17 and Comparative Polymers 1 to 5, respectively, and changing the draw ratio as described in Table 1 below A biaxially stretched film was produced in the same manner as in Example 1. In Examples 1 to 11 and Comparative Examples 1 to 5, the draw ratio was 5% to 10% before the breaking elongation. In Example 12, a biaxially stretched film was produced using P-13 in the same manner as in Example 8 while reducing the stretch ratio to 30%.

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

<Linear thermal expansion coefficient>
A film sample (19 mm × 5 mm) was prepared and measured using TMA (manufactured by Rigaku Corporation, TMA8310). The measurement speed was 3 ° C./min. Three samples were measured and the average value was used. The measurement was performed in a temperature range of 25 ° C. to 300 ° C., and the linear thermal expansion coefficient was calculated in the range of 25 ° C. to 200 ° C. when the temperature was raised. However, for a sample having a glass transition temperature of 200 ° C. or lower, calculation was performed in a temperature range of 25 ° C. to 150 ° C.

<Evaluation of transparency>
The film obtained above was visually observed, and the following determination was made to evaluate transparency.
○: Good transparency.
Δ: Partially cloudy is observed.
X: White turbidity is remarkable and heterogeneous.

<Weight average molecular weight>
Using “HLC-8120GPC” manufactured by Tosoh Corporation, the weight average molecular weight was determined by polystyrene conversion GPC measurement using tetrahydrofuran as a solvent in comparison with a molecular weight standard product of polystyrene.

The obtained results are shown in Table 1 below.

As shown in Table 1, the films of Examples 1 to 12 have a Tg in a range suitable for melt film formation, a range in which dimensional stability during a heating process laminated with ITO does not deteriorate, and a linear thermal expansion coefficient. Was also found to be small. On the other hand, the film of Comparative Example 1 was produced using only phenol not having a structure similar to the general formula (1), and although Tg was in a range suitable for melt film formation, The expansion coefficient was large. The film of Comparative Example 2 was produced using phenol in which R ¹¹ to R ¹⁸ in the general formula (1) are out of the scope of the present invention, and has a small amount of linear components and a large linear thermal expansion coefficient. The film of Comparative Example 3 was produced using only the dicarboxylic acid not having the structure represented by the general formula (4). The Tg was too high to be suitable for melt film formation, and the transparency was poor. It was. The film of Comparative Example 4 was produced using only phenol that does not have the structure represented by the general formula (3), and because of poor stretchability, the linear thermal expansion coefficient was large. Comparative Example 5 This film was produced using only a dicarboxylic acid not having the structure represented by the general formula (2) and using only a phenol not having the structure represented by the general formula (3). Yes, Tg was too high to be suitable for melt film formation, and the transparency was poor.

[Examples 101 to 112, Comparative Examples 101 to 105]
1. Forming Examples 1-12 of the gas barrier layer, by DC magnetron sputtering on both surfaces of the film of Comparative Examples 1-5, under a vacuum of target the Si0 ₂ 500 Pa, an Ar atmosphere, and sputtering at an output 5 kW, with a gas barrier layer Films of Examples 101 to 112 and Comparative Examples 101 to 105 were obtained. The film thickness of the obtained gas barrier layer was 60 nm. The water vapor permeability at 40 ° C. and 90% relative humidity was 0.1 g / m ² · day or less.

[Examples 201 to 212, Comparative examples 201 to 205]
2. Formation of Transparent Conductive Layer While heating the films of Examples 101 to 112 and Comparative Examples 101 to 105 provided with gas barrier layers to 100 ° C., ITO (In ₂ O ₃ 95% by mass, SnO ₂ 5% by mass) was used as a target. A film of Examples 201 to 212 and Comparative Examples 201 to 205 was formed on one side by a DC magnetron sputtering method under a vacuum of 0.665 Pa, an Ar atmosphere, an output of 5 kW, and a transparent conductive layer made of an ITO film having a thickness of 140 nm. Respectively. The water vapor permeability of each of the films of Examples 201 to 212 and Comparative Examples 201 to 205 at 40 ° C. and 90% relative humidity is 0.1 g / m ² · day or less, and oxygen permeation at 40 ° C. and 90% relative humidity. All the degrees were 0.1 ml / m ² · day · atm or less. Moreover, the surface electrical resistance of ITO at 25 ° C. and a relative humidity of 60% was 30Ω / □.

<Evaluation of gas barrier property and surface electrical resistance change by heating test>
Gas barrier properties and surface electricity before and after heat treatment of the gas barrier films of Examples 101 to 112 and Comparative Examples 101 to 105 produced above and those of Examples 201 to 212 with a transparent conductive layer and films of Comparative Examples 201 to 205 The change in resistance was measured.
The heat treatment condition was that the temperature was raised from room temperature to 160 ° C. under nitrogen, held at 160 ° C. for 2 hours, and then cooled to room temperature.

The films of Examples 101 to 112 and Examples 201 to 212 of the present invention showed no change in gas barrier properties and surface electrical resistance before and after the heat treatment, but the films of Comparative Examples 101 to 105 and 201 to 205 had both physical properties. It was getting worse. This is because the film of the present invention has a small coefficient of linear thermal expansion, so that the difference in expansion from the inorganic layer is small.

[Examples 301 to 312 and Comparative Examples 301 to 305]
<Production and Evaluation of Organic EL Device>
Organic EL element samples were prepared using the films of Examples 201 to 212 and Comparative Examples 201 to 205 with a transparent conductive layer of the present invention, respectively.
Aluminum lead wires were connected from the transparent electrode layers of the films of Examples 201 to 212 and Comparative Examples 201 to 205 in which the transparent conductive layer was formed as described above to form a laminated structure. The surface of the transparent electrode was spin-coated with an aqueous dispersion of polyethylene dioxythiophene / polystyrene sulfonic acid (BAYER, Baytron P: solid content: 1.3% by mass), and then vacuum-dried at 150 ° C. for 2 hours. A hole-transporting organic thin film layer having a thickness of 100 nm was formed. This was designated as substrate X.
On the other hand, a coating solution for a light-emitting organic thin film layer having the following composition was formed on one surface of a temporary support made of 188 μm thick polyethersulfone (Sumilite FS-1300 manufactured by Sumitomo Bakelite Co., Ltd.) using a spin coater. The luminescent organic thin film layer having a thickness of 13 nm was formed on the temporary support by applying and drying at room temperature. 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.

Further, a patterned evaporation mask (a mask having a light emission area of 5 mm × 5 mm) is placed on one side of a polyimide film (UPILEX-50S, manufactured by Ube Industries) having a thickness of 50 μm cut into a 25 mm square. Al was evaporated in a reduced pressure atmosphere of 1 mPa to form an electrode having a film 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, whereby an electron having a thickness of 15 nm is obtained. A transportable 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 the substrate XY and the substrate Z, the electrodes are stacked so that the electrodes face each other with the light-emitting organic thin film layer interposed therebetween, and heated and pressed at 160 ° C., 0.3 MPa, 0.05 m / min using a pair of heat rollers. The organic EL element sample was obtained by bonding.

A direct voltage was applied to the organic EL element from the obtained organic EL element sample using a source measure unit 2400 type (manufactured by Toyo Technica Co., Ltd.). It was confirmed that the samples produced using the films of Examples 201 to 212 of the present invention emitted light. On the other hand, the samples prepared using the films of Comparative Examples 201 to 205 emitted light for a moment but stopped emitting light immediately.
The films of Examples 201 to 212 of the present invention have a small coefficient of linear thermal expansion, and the inorganic layer was not cracked by heating in the sample preparation process, but the films of Comparative Examples 201 to 205 have a large coefficient of linear thermal expansion. This is because the inorganic layer was heated and cracked.

The resin of the present invention has an appropriate glass transition temperature and a low coefficient of linear thermal expansion when performing efficient melt film formation. Moreover, since the film using this resin shows a small linear thermal expansion coefficient, it can be used as a gas barrier film, a transparent conductive film, or a substrate for an image display device.

Claims (15)

1. A structure represented by the following general formula (1), a structure represented by the following general formula (2), a structure represented by the following general formula (3), and a structure represented by the following general formula (4) A polyester resin characterized by that.
   

   

   (In the general formula (1), R ¹¹ to R ¹⁴ each independently represents a hydrogen atom or a substituent, provided that at least one of R ¹¹ to R ¹⁴ is a substituent. R ¹⁵ to R ¹⁸ are hydrogen atoms. Represents.)
   

   

   (In the general formula (2), R ²¹ to R ²⁴ each independently represents a hydrogen atom or a substituent, and l represents a natural number.)
   

   

   (In the general formula (3), R ³¹ and R ³² each independently represent a substituent, m and n each independently represent an integer of 0 to 4, and X represents a divalent linking group, provided that X Is not part of the ring structure.)
   

   

   (In the general formula (4), R ²⁵ to R ²⁸ each independently represents a hydrogen atom or a substituent.)
2. 2. The polyester resin according to claim 1, wherein in the general formula (1), at least one of the R ¹¹ to R ¹⁴ is a halogen atom, an alkyl group, a cyano group, or an alkoxy group.
3. 2. The polyester resin according to claim 1, wherein in the general formula (1), at least one of the R ¹¹ to R ¹⁴ is a chlorine atom, a methyl group or a methoxy group.
4. The polyester resin according to any one of claims 1 to 3, which satisfies the following formula (A).
   a + 0.5 × c ≧ 70 (A)
   (In formula (A), a is the content (unit: mol%) of the structure derived from the aromatic diol represented by the general formula (1) with respect to the structure derived from all aromatic diols contained in the polyester resin. And c represents the content (unit: mol%) of the structure derived from the dicarboxylic acid represented by the general formula (2) with respect to all the structures derived from the dicarboxylic acid contained in the polyester resin.
5. The polyester resin according to any one of claims 1 to 4, comprising a structure represented by the following general formula (5).
   

   

   (In the general formula (5), R ⁴¹ and R ⁴² each independently represent a substituent, and p and q each independently represents an integer of 0 to 3.)
6. The polyester resin according to any one of claims 1 to 5, wherein the light transmittance at a wavelength of 400 nm when the polyester resin is a film having a thickness of 100 µm is 50% or more.
7. The polyester resin according to any one of claims 1 to 6, wherein the glass transition temperature (Tg) is 170 ° C or higher.
8. The polyester resin according to any one of claims 1 to 7, which has a glass transition temperature (Tg) of 250 ° C or lower.
9. 9. The polyester resin according to claim 1, wherein the weight of the structure represented by the general formula (2) is larger than the weight of the structure represented by the general formula (4). .
10. An optical material comprising the polyester resin according to any one of claims 1 to 9.
11. A film comprising the polyester resin according to any one of claims 1 to 9.
12. The film according to claim 11, wherein the linear thermal expansion coefficient is 40 ppm / K or less.
13. The film according to claim 11 or 12, further comprising a gas barrier layer.
14. The film according to any one of claims 11 to 13, further comprising a transparent conductive layer.
15. An image display device using at least one film according to any one of claims 11 to 14.