Phase difference film and its applications

Abstract

A phase difference film is formed by combining a polyester resin that exhibits negative orientation birefringence and a phase difference that exhibits net wavelength dispersion, and a polyamide resin that exhibits positive orientation birefringence and a phase difference that exhibits flat dispersion. The polyester resin may include a constituent unit having a fluorene-9,9-diyl group, and the polyamide resin may include a constituent unit having a cycloaliphatic backbone. The polyester resin may include at least one constituent unit selected from a fluoredicarboxylic acid unit (A1) having a unit represented by the following formula (1), and a fluorediol unit (B1) having a unit represented by the following formula (2). (In the formula, R1 and R2 are substituents, k and m are integers from 0 to 8, X1a, X1b, X2a, and X2b are hydrocarbon groups, A1a and A1b are alkylene groups, and n1 and n2 are integers greater than or equal to 0.) The above phase difference film achieves both high phase difference expression and inverse wavelength dispersibility.

Description

Technology Field

[0001] The present disclosure relates to a phase difference film and its uses. Background Technology

[0002] Various phase difference films are used in image display devices installed in televisions, smartphones, etc., depending on their type.

[0003] For example, in image display devices such as reflective liquid crystal displays, transflective liquid crystal displays, touch panel displays, and organic EL displays, a circular polarizer is used to control the polarization state to display an image or to absorb reflected light to ensure visibility. This is achieved by laminating a quarter-wave plate and a polarizer (linear polarizer) such that the absorption axis of the polarizer is at an angle of 45° to the ground axis of the quarter-wave plate. In particular, as organic EL displays are increasingly being adopted in televisions as well as smartphones, the importance of circular polarizers, which have excellent wavelength dispersion over a wide bandwidth, is increasing due to the need to prevent external light reflection to improve visibility and contrast ratio. Specifically, in organic EL displays, by absorbing reflected light with a circular polarizer and suppressing light leakage, it is possible to prevent blue coloration and improve visibility, and at the same time, since insufficient black display associated with the coloration can be prevented, the contrast ratio can also be improved. For this reason, if the circular polarizer does not have a phase difference film (broadband quarter-wave plate) that exhibits inverse wavelength dispersion in which the phase difference in the broadband of visible light is approximately one-quarter wavelength, there is a risk that reflected light of a specific wavelength will leak out, thereby reducing visibility or contrast ratio.

[0004] General polymers often exhibit net wavelength dispersion, in which the phase difference decreases as the wavelength increases, or flat dispersion, in which the phase difference does not change much, while polymers exhibiting inverse wavelength dispersion, in which the phase difference increases as the wavelength increases, are limited. As films of polymers exhibiting such inverse wavelength dispersion, polyester resin films such as copolymerized polycarbonates or copolymerized polyesters have been developed and are employed in circular polarizers, comprising structural units having a cardo structure in which the directional ring of the main chain and the directional ring of the side chain are orthogonal, i.e., a 9,9-bisphenylfluorene backbone, and structural units having an isosorbide ring or a cyclohexane ring.

[0005] Meanwhile, phase difference films exhibiting inverse wavelength dispersion are also required for large liquid crystal displays (LCDs), particularly for liquid crystal televisions. Among the two types of liquid crystal televisions—vertical alignment type (VA-LCD) and in-plane driving type (IPS-LCD)—VA-LCD, which has high frontal contrast and very wide viewing angles in the up, down, left, and right directions, is the mainstream. In this VA method, it is difficult to secure a high viewing angle with high contrast in the oblique direction, so a phase difference film is placed between the liquid crystal cell and the polarizing plates arranged above and below it to secure the viewing angle in the oblique direction.

[0006] In phase difference films for VA-LCDs, inverse wavelength dispersion is very important from the perspective of compensating for phase difference (or viewing angle) across the entire visible light range, and in particular, it is said to be effective in suppressing color shift, in which the color changes with changes in viewing angle. As a material for such phase difference films for VA-LCDs, cellulose acetate propionate (CAP), which can impart inverse wavelength dispersion through additives, is used.

[0007] However, recently, the open-cell method of transporting liquid crystal panels to television set makers in simple packages has increased, and problems are arising due to moisture absorption by the CAP during transport, which causes issues with the image display function. For this reason, although there is an increasing number of cases where cyclic olefin copolymers (COPs) are adopted instead of highly absorbent CAPs, COPs have flat dispersion and cannot effectively suppress color shift. Prior art literature

[0008] Japanese Published Patent Application No. 2010-134232, Japanese Published Patent Application No. 2012-31369, Japanese Published Patent Application No. 2018-151627 The problem to be solved

[0009] Recently, thinning of phase difference films is required to thin or lighten displays. However, since phase difference is proportional to the thickness of the film, it is necessary to adjust the birefringence to a high level in order to thin the film while maintaining the desired phase difference. Although the films exhibiting inverse wavelength dispersion described in Patent Documents 1 to 3 generate a phase difference through uniaxial stretching, they all have low intrinsic birefringence (or phase difference generation ability). Therefore, to form them into thin films, it is difficult to obtain the desired phase difference unless the stretching conditions are strictly controlled to increase the orientation birefringence. However, since these polymers are mainly formed with rigid structures including cardo structures and ring structures such as isosorbide rings or cyclohexane rings, the films are brittle and prone to fracture during stretching, so there are limits to strictly controlling the stretching conditions. In particular, it is very difficult to form phase difference films for VA-LCDs that adjust the phase difference by biaxial stretching, which has stricter stretching conditions than uniaxial stretching.

[0010] Furthermore, even if it can be formed into a thin film by stretching, its brittleness poses a risk of insufficient mechanical strength and difficulty in handling. Additionally, under strict stretching conditions, residual stress causes film shrinkage, which may lead to a decrease in environmental reliability (heat resistance, water resistance (moisture resistance), dimensional stability against heat or moisture, and phase difference stability). Consequently, it is not possible to manufacture thin, high-quality phase difference films easily or efficiently.

[0011] In addition, high phase difference and inverse wavelength dispersion generally tend to be in a trade-off relationship. That is, for films with inverse wavelength dispersion, the phase difference increases as stretching conditions are tightened, but the wavelength dispersion characteristics tend to change from inverse dispersion to net dispersion (or positive dispersion). Therefore, it is not easy to simultaneously satisfy the desired phase difference and inverse wavelength dispersion through stretching conditions. In particular, since films with inverse wavelength dispersion typically have low phase difference expression as mentioned above, it is even more difficult to achieve the compatibility of phase difference and inverse wavelength dispersion.

[0012] Accordingly, the object of the present disclosure is to provide a novel phase difference film that achieves both high phase difference expression and inverse wavelength dispersion (inverse wavelength dispersion of the in-plane phase difference Ro) and its uses. means of solving the problem

[0013] The inventors, as a result of careful consideration to achieve the above objective, discovered that if a phase difference film is formed by combining a polyester resin having negative orientation birefringence in a single film and exhibiting net wavelength dispersibility, and a polyamide resin having positive orientation birefringence in a single film and exhibiting flat dispersibility, it exhibits high phase difference expression and inverse wavelength dispersibility, and thus completed the present invention.

[0014] That is, the phase difference film of the present disclosure comprises a polyester-based resin that exhibits negative orientation birefringence and also exhibits net wavelength dispersion of the phase difference, and a polyamide-based resin that exhibits positive orientation birefringence and also exhibits flat dispersion of the phase difference.

[0015] The above polyester resin may include a constituent unit having a fluorene-9,9-diyl group, and the above polyamide resin may include a constituent unit having a dicyclic skeleton. The above polyester resin may include at least one constituent unit selected from a fluorene dicarboxylic acid unit (A1) and a fluorene diol unit (B1) as the constituent unit having a fluorene-9,9-diyl group, and the fluorene dicarboxylic acid unit (A1) may include a dicarboxylic acid unit represented by the following formula (1), and the fluorene diol unit (B1) may include a diol unit represented by the following formula (2).

[0016] [Chemical Formula 1]

[0017]

[0018] (during food, R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b Each represents a divalent hydrocarbon group that may independently have a substituent).

[0019] [Chemical Formula 2]

[0020]

[0021] (during food, R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b represents a divalent hydrocarbon group that may each independently have a substituent, and A 1a and A 1bEach independently represents a straight-chain or branched-chain alkylene group, and n1 and n2 represent integers greater than or equal to 0).

[0022] The above fluorediol unit (B1) may include a diol unit represented by the following formula (2A).

[0023] [Chemical Formula 3]

[0024]

[0025] (in food, Z 1a and Z 1b Each independently represents an Aren ring, and R 3a and R 3b ☐ each independently represents a substituent, p1 and p2 each independently represent an integer greater than or equal to 0, and R 2 , m, A 1a and A 1b , n1 and n2 are each the same as Equation (2) above).

[0026] The above polyester resin may include a (poly)alkylene glycol unit (B2) represented by the following formula (3).

[0027] [Chemical Formula 4]

[0028]

[0029] (during food, A 2 represents a straight-chain or branched-chain alkylene group, and q represents an integer greater than or equal to 1).

[0030] The above polyester resin is, in the above formula (1), X 1a and X 1b a straight chain type or branched chain type C 2-4 It is an alkylene group, and

[0031] In the above equation (2A), Z 1a and Z 1b Ga C 6-12 It is an Aren ring, and R 3a and R 3b Ga C 1-4alkyl group or C 6-10 It is an aryl group, p1 and p2 are integers from 0 to 2, and A 1a and A 1b a straight chain type or branched chain type C 2-4 It is an alkylene group, where n1 and n2 are integers from 0 to 2, and

[0032] In the above equation (3), A 2 a straight chain type or branched chain type C 2-4 It is an alkylene group, and q may be an integer from 1 to 4.

[0033] The above polyamide resin may include a diamine unit represented by the following formula (4).

[0034] [Chemical Formula 5]

[0035]

[0036] (during food, Y 1 represents a divalent hydrocarbon group that may be directly bonded or have a substituent, and R 4a and R 4b Each represents a substituent independently, and r1 and r2 each represent an integer from 0 to 4 independently).

[0037] The above polyamide resin may include a constituent unit (dicarboxylic acid unit) derived from an aliphatic dicarboxylic acid component. The above polyamide resin is, in the above formula (4), Y 1 This C 1-4 It is an alkylene group, and R 4a and R 4b Ga C 1-4 It is an alkyl group, a diamine unit in which r1 and r2 are 0 or 1, and a straight-chain or branched-chain C 4-16 It may contain a constituent unit (dicarboxylic acid unit) derived from an alkane-dicarboxylic acid component.

[0038] In the above phase difference film, the difference between the glass transition temperature of the polyester resin and the glass transition temperature of the polyamide resin may be approximately 0 to 20°C. The above phase difference film may be a laminated film comprising a first layer containing a polyester resin and a second layer containing a polyamide resin. The above phase difference film may be a laminated film with a three-layer structure in which the second layer is laminated on both sides of the first layer, and preferably, a laminated film with a three-layer structure in which the first layer is laminated on both sides of the second layer. In the above phase difference film, the ratio of the total thickness of the first layer to the total thickness of the second layer may be approximately 1 / 1 to 10 / 1. The thickness of the above phase difference film may be approximately 20 to 70 μm.

[0039] The above phase difference film may be a uniaxially stretched film. The above phase difference film may be a uniaxially stretched film that is stretched obliquely with respect to the film length direction, and the angle formed between the ground axis within the film plane and the film length direction may be approximately 40 to 50°. When the in-plane phase difference at wavelength λ nm is Ro (λ), the above phase difference film may have a Ro (550) of approximately 100 to 160 nm and a Ro (450) / Ro (550) of approximately 0.7 or more and less than 1. The above phase difference film may be a quarter-wave plate.

[0040] Additionally, the phase difference film may be a biaxially stretched film. The phase difference film may have a ground axis within the film plane that is approximately perpendicular to the film length direction, for example, about 85 to 95°. When the in-plane phase difference at wavelength λ nm is Ro (λ) and the thickness direction phase difference is Rth (λ), the phase difference film may have a Ro (550) of about 30 to 50 nm, a Ro (450) / Ro (550) of about 0.7 or more and less than 1, and a Rth (589) of about 120 to 140 nm. The phase difference film may be an optical compensation film for a vertically aligned liquid crystal display.

[0041] The present disclosure also includes a polarizer comprising the phase difference film and an image display device comprising the polarizer. The image display device may be an organic EL display or a vertically aligned liquid crystal display.

[0042] In addition, in the scope of this specification and claims, “positive” means a property in which the refractive index in the orientation direction (or stretching direction) within the plane of the polymer orientation film (or uniaxially stretched film) has a value greater than the refractive index in the direction perpendicular to the orientation direction, and “negative” means a property in which the refractive index in the orientation direction has a value smaller than the refractive index in the direction perpendicular to the orientation direction.

[0043] Also, regarding wavelength dispersion, "net wavelength dispersion" or "net dispersion (or positive dispersion)" in this specification and claims means a property in which the absolute value of the in-plane phase difference Ro decreases as the wavelength increases, particularly that Ro (450) / Ro (550) at a measurement temperature of 20°C is greater than 1.05; "inverse wavelength dispersion" or "inverse dispersion" means a property in which the absolute value of the in-plane phase difference Ro increases as the wavelength increases, particularly that Ro (450) / Ro (550) at a measurement temperature of 20°C is less than 1; and "flat dispersion (or flat dispersion)" means a property in which the absolute value of the in-plane phase difference Ro hardly changes with wavelength, particularly that Ro (450) / Ro (550) at a measurement temperature of 20°C is 1 to 1.05.

[0044] In addition, in the present specification and claims, “diol unit” or “constituent unit derived from a diol component” means a unit (or a divalent group) obtained by removing two hydrogen atoms from two hydroxyl groups of a corresponding diol component, and “diol component” (including compounds exemplified as diol components) may be used with the same meaning as the corresponding “diol unit.”

[0045] Likewise, “dicarboxylic acid unit” or “constituent unit derived from a dicarboxylic acid component” means a unit (or a divalent group) obtained by removing two OH (hydroxyl groups) from two carboxyl groups of the corresponding dicarboxylic acid, and “dicarboxylic acid component” (including compounds exemplified as dicarboxylic acid components) may be used with the same meaning as the corresponding “dicarboxylic acid unit.”

[0046] Furthermore, in this specification and claims, the term "dicarboxylic acid component" is used to mean that, in addition to the dicarboxylic acid, it includes its ester-forming derivatives, for example, dicarboxylic acid lower alkyl esters, dicarboxylic acid halides, dicarboxylic acid anhydrides, etc. As for the dicarboxylic acid lower alkyl esters, for example, C-methyl esters, ethyl esters, t-butyl esters, etc. 1-4 Examples include alkyl esters, etc. Examples of the above dicarboxylic acid halides include dicarboxylic acid chloride, dicarboxylic acid bromide, etc. In addition, the "ester-forming derivative" may be a monoester (half-ester) or a diester.

[0047] Also, “diamine unit” or “constituent unit derived from a diamine component” means a unit (or a divalent group) obtained by removing one hydrogen atom from each of the two amino groups of the corresponding diamine, and “diamine component” (including compounds exemplified as diamine components) may be used with the same meaning as the corresponding “diamine unit.”

[0048] In addition, in the scope of this specification and claims, the number of carbon atoms of the substituent is C1, C6, C 10 There are cases where they are represented as such. For example, an alkyl group with 1 carbon atom is represented as "C1alkyl," and an aryl group with 6 to 10 carbon atoms is represented as "C 6-10 It is represented as "Aril". Effects of the invention

[0049] The phase difference film of the present disclosure is formed by combining a polyester resin that exhibits negative orientation birefringence and also exhibits net wavelength dispersion of the phase difference with a polyamide resin that exhibits positive orientation birefringence and also exhibits flat dispersion of the phase difference, thereby enabling the compatibility of high phase difference expression and excellent (or appropriate) reverse wavelength dispersion. Therefore, even when formed as a thin film, it is easy to maintain the desired phase difference, and a phase difference film with an excellent balance of thinness, phase difference, and reverse wavelength dispersion can be formed. In addition, since it is easy to express the phase difference even under relatively mild stretching conditions, moldability (or productivity) and environmental reliability are also high. In particular, by combining a polyester resin containing a constituent unit having a predetermined fluorene-9,9-diyl group and a polyamide resin containing a constituent unit having a predetermined alicyclic skeleton, a film with excellent toughness (or flexibility) can be prepared, thereby further improving moldability and handling properties. Therefore, a broadband quarter-wave plate or a phase difference film for VA-LCD that can suppress color shift can be easily or efficiently formed. Specific details for implementing the invention

[0050] In the present disclosure, a phase difference film is formed by combining a predetermined polyester-based resin and a predetermined polyamide-based resin.

[0051] [Polyester resin]

[0052] The polyester resin may be a resin that exhibits negative orientation birefringence in its single film (uniaxially stretched film) and also exhibits net wavelength dispersion of phase difference. From the perspective of making it easier to adjust a phase difference film with excellent reverse wavelength dispersion, the net wavelength dispersion of the polyester resin is a net wavelength dispersion with a large change in phase difference with respect to wavelength (steep net wavelength dispersion), for example, Ro(450) / Ro(550) at a measurement temperature of 20°C is about 1.1 to 1.3, preferably 1.12 to 1.25, and more preferably 1.15 to 1.2. Examples of polyester resins include polyester resin, polycarbonate resin, polyester carbonate resin, etc. These polyester resins may be included alone or in combination of two or more types. Among these polyester resins, polyester resin is preferred in terms of moldability and phase difference expression.

[0053] Examples of polyester resins exhibiting the above characteristics include polyester resins containing constituent units having fluorene ring-containing groups such as fluorene-9,9-diyl groups (or fluoronylidene groups) and 9-fluorenyl groups, and preferably polyester resins containing constituent units having fluorene-9,9-diyl groups (resin having a fluorene ring at the 9 position on the main chain and a fluorene ring as a side chain).

[0054] The polyester resin preferably comprises a dicarboxylic acid component (A) and a diol component (B) as polymerization components, and the constituent unit having a fluorene ring-containing group may be a unit derived from any of the polymerization components, but at least the dicarboxylic acid unit (A) has a dicarboxylic acid unit having a fluorene ring-containing group (hereinafter also referred to as a fluorene dicarboxylic acid unit) (A1), and in particular, it is preferable that both the dicarboxylic acid unit (A) and the diol unit (B) have constituent units having a fluorene ring-containing group.

[0055] (Dicarboxylic acid unit (A))

[0056] Fluorendicarboxylic acid unit (A1)

[0057] Fluorendicarboxylic acid units (A1) include dicarboxylic acid units represented by the following formula (1).

[0058] [Chemical Formula 6]

[0059]

[0060] (during food, R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b Each represents a divalent hydrocarbon group that may independently have a substituent).

[0061] In the above equation (1), X 1a and X 1b As the divalent hydrocarbon group in [the example], it may be a divalent aromatic hydrocarbon group such as a phenylene group, but a divalent alicyclic hydrocarbon group such as a cyclohexylene group or a divalent aliphatic hydrocarbon group is preferred, and a divalent aliphatic hydrocarbon group is particularly preferred. X forming the main chain 1a and X 1bWhen α is a divalent alicyclic or aliphatic hydrocarbon group, due to the combination with the fluorene ring structure (fluorene-9,9-diyl group) of the side chain, the wavelength dependence of the refractive index in the direction of the main chain is small, while the wavelength dependence of the refractive index in the direction orthogonal to the main chain is large. Consequently, orientational birefringence is negative, making it easier to formulate polyester resins that exhibit net wavelength dispersibility and also have a large wavelength dependence. In particular, X 1a and X 1b If the group is a divalent aliphatic hydrocarbon group, the phase difference expression is enhanced, making it possible to stretch under milder stretching conditions. Furthermore, it is desirable to form a thinner phase difference film because the toughness (flexibility) of the polyester resin is improved, making it difficult to break and allowing for the formation of a film with excellent moldability and handling properties, or because thermal shrinkage due to residual stress is reduced.

[0062] Ki X 1a and X 1b The divalent aliphatic hydrocarbon group represented by may be a straight-chain or branched-chain alkenylene group, a straight-chain or branched-chain alkynylene group, etc., but is preferably a straight-chain or branched-chain alkylene group. As for the straight-chain or branched-chain alkylene group, for example, a straight-chain or branched-chain C such as a methylene group, an ethylene group, a trimethylene group, a propylene group, a 1,2-butanediyl group, a 2-methylpropane-1,3-diyl group, etc. 1-8 Examples include alkylene groups, etc. Among these, preferably straight-chain or branched-chain C 1-6 An alkylene group, more preferably a straight-chain or branched-chain type C 1-4 It is an alkylene group, and more preferably a straight-chain or branched-chain type C 2-4 It is an alkylene group, and among them, a straight-chain or branched-chain type C such as an ethylene group or a propylene group. 2-3 An alkylene group is preferred, and an ethylene group is particularly preferred. In addition, X 1a and X 1bThey may be different from each other, but it is desirable that they be of the same cause.

[0063] Also, X 1a and X 1b Examples of substituents that the divalent hydrocarbon group represented by may have include aryl groups such as phenyl groups, cycloalkyl groups such as cyclohexyl groups, etc. The number of substituents is not particularly limited and is, for example, 0 to 10, preferably 0 to 2, more preferably 0 or 1, particularly 0. Examples of divalent hydrocarbon groups having substituents may include 1-phenylethylene groups, 1-phenylpropane-1,2-diyl groups, etc. Also, X 1a and X 1b It is preferable that it be a straight-chain or branched-chain alkylene group without substituents.

[0064] In the above equation (1), R 1 The group may be a non-polymerizable group or a non-reactive substituent that is inactive to the polymerization reaction, for example, a cyano group; a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom; or a hydrocarbon group such as an alkyl group or an aryl group. The above aryl group may include C groups such as a phenyl group. 6-10 Examples include aryl groups. Desirable group R 1 The rheo is a cyano group, a halogen atom, or an alkyl group, and is particularly an alkyl group.

[0065] The above alkyl group is, for example, a C group such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, etc. 1-12 Alkyl group, preferably C 1-8 C, especially alkyl groups such as methyl groups 1-4 Examples include alkyl groups, etc.

[0066] Also, Gi R 1 When the number of substitutions k is plural (2 or more), among the two benzene rings constituting the fluorene ring, 2 or more groups R that are substituted with the same benzene ring 1The types may be the same or different, and two or more groups R substituted with different benzene rings 1 The type may be the same or different. Also, the R 1 The bonding position (substitution position) is not particularly limited, and examples include the 2nd position, 7th position, 2nd, 7th position of the fluorene ring, etc.

[0067] The number of substitutions k may be an integer of, for example, 0 to 6, and in a preferred range, is an integer of 0 to 4, 0 to 3, 0 to 2 in steps below, and preferably 0 or 1, particularly 0. In addition, regarding the two benzene rings constituting the fluorene ring, group R 1 The number of substitutions for each of the may be different from each other, but it is preferable that they be the same.

[0068] Representative dicarboxylic acid units represented by the above formula (1) include X 1a and X 1b a straight chain type or branched chain type C 2-6 Constituent units that are alkylene groups, for example, 9,9-bis(2-carboxyethyl)fluorene, 9,9-bis(2-carboxypropyl)fluorene, etc., 9,9-bis(carboxyC 2-6 Examples include constituent units derived from alkyl)fluorenes. These dicarboxylic acid units represented by Formula (1) may be used alone or in combination of two or more. Among these dicarboxylic acid units represented by Formula (1), preferably 9,9-bis(carboxy C 2-6 Alkyl)fluorene, more preferably 9,9-bis(carboxy C 2-4 It is an alkyl)fluorene, in particular, 9,9-bis(2-carboxyethyl)fluorene, 9,9-bis(2-carboxypropyl)fluorene, etc., 9,9-bis(carboxy C 2-3 It is preferable to include a constituent unit derived from alkyl)fluorene.

[0069] The fluoredicarboxylic acid unit (A1) may be used alone or in combination of two or more types. The ratio of the dicarboxylic acid unit represented by the above formula (1) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol%, with respect to the total fluoredicarboxylic acid unit (A1). The preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable that the fluoredicarboxylic acid unit (A1) substantially comprises only the dicarboxylic acid unit represented by the above formula (1). If the ratio of the dicarboxylic acid unit represented by the above formula (1) is excessively low, there is a risk that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersion cannot be formed.

[0070] Also, among the dicarboxylic acid units represented by the above formula (1), X 1a and X 1b a straight-chain or branched-chain alkylene group, in particular, a straight-chain or branched-chain C 2-6 The proportion of the alkylene group constituent unit can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol%, with respect to the total dicarboxylic acid unit represented by Formula (1), and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, substantially the dicarboxylic acid unit represented by Formula (1) is X 1a and X 1b a straight-chain or branched-chain alkylene group, in particular, a straight-chain or branched-chain C 2-6 It is preferable to include only constituent units that are alkylene groups. X 1a and X 1ba straight-chain or branched-chain alkylene group, in particular, a straight-chain or branched-chain C 2-6 If the proportion of alkylene group constituent units is excessively low, there is a concern that it may not be possible to form a polyester resin exhibiting negative orientation birefringence and net wavelength dispersion, and there is also a concern that it may be difficult to form a thinner phase difference film.

[0071] Second dicarboxylic acid unit (A2)

[0072] The polyester resin does not have to include a dicarboxylic acid unit (a second dicarboxylic acid unit (A2)) that is different from the fluoredicarboxylic acid unit (or a first dicarboxylic acid unit) (A1) as a dicarboxylic acid unit (A), but may include it as needed as long as it does not impede the effects of the present disclosure.

[0073] The second dicarboxylic acid unit (A2) may be a constituent unit derived from, for example, an aromatic dicarboxylic acid component [except for the fluoredicarboxylic acid component (A1)], a dicarboxylic acid component, an aliphatic dicarboxylic acid component, etc.

[0074] Examples of aromatic dicarboxylic acid components include, for instance, benzenedicarboxylic acids, alkylbenzenedicarboxylic acids, polycyclic arendicarboxylic acids, diarylalkanedicarboxylic acids, diarylketonedicarboxylic acids, and ester-forming derivatives thereof.

[0075] Examples of benzenedicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, etc.

[0076] As alkylbenzenedicarboxylic acids, for example, C of 4-methylisophthalic acid, 5-methylisophthalic acid, etc. 1-4 Examples include alkyl-benzenedicarboxylic acids.

[0077] Examples of polycyclic arendicarboxylic acids include condensed polycyclic arendicarboxylic acids and ring-assembling arendicarboxylic acids.

[0078] Condensed polycyclic arendicarboxylic acids include, for example, naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; condensed polycyclic C such as anthracenedicarboxylic acid; and phenanthrendicarboxylic acid. 10-24 Arendicarboxylic acid, preferably a condensed polycyclic type C 10-14 Examples include arendicarboxylic acid.

[0079] As cyclic areendicarboxylic acids, for example, non-C such as 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. 6-10 Examples include arendicarboxylic acid.

[0080] As for diaryl alkanedicarboxylic acids, for example, diC of 4,4'-diphenylmethanedicarboxylic acid, etc. 6-10 Aril C 1-6 Examples include alkanes and dicarboxylic acids.

[0081] As for diaryl ketone dicarboxylic acids, for example, di(C) of 4,4'-diphenyl ketone dicarboxylic acid, etc. 6-10 Examples include aryl ketones and dicarboxylic acids.

[0082] Examples of cycloalkanedicarboxylic acid components include, for instance, cycloalkanedicarboxylic acids, cross-linked cyclic cycloalkanedicarboxylic acids, cycloalkenedicarboxylic acids, cross-linked cyclic cycloalkanedicarboxylic acids, and ester-forming derivatives thereof.

[0083] As cycloalkanedicarboxylic acids, for example, C of 1,4-cyclohexanedicarboxylic acid, etc. 5-10 Examples include cycloalkanes and dicarboxylic acids.

[0084] Examples of cross-linked cyclic cycloalkanedicarboxylic acids include, for instance, decalin dicarboxylic acid, norbornandicarboxylic acid, adamantandicarboxylic acid, tricyclodecanedicarboxylic acid, and tricycloalkanedicarboxylic acids.

[0085] As for cycloalkene dicarboxylic acids, for example, C of cyclohexene dicarboxylic acid, etc. 5-10 Examples include cycloalkene-dicarboxylic acids.

[0086] Examples of cross-linked cyclic cycloalkene dicarboxylic acids include dicycloalkene dicarboxylic acids such as norbornene dicarboxylic acid or tricycloalkene dicarboxylic acids.

[0087] Examples of aliphatic dicarboxylic acid components include alkanedicarboxylic acids, unsaturated aliphatic dicarboxylic acids, and ester-forming derivatives thereof.

[0088] Alkanedicarboxylic acids include, for example, C of succinic acid, adipic acid, sebacic acid, decandicarboxylic acid, etc. 2-12 Examples include alkanes and dicarboxylic acids.

[0089] Unsaturated aliphatic dicarboxylic acids include, for example, C of maleic acid, fumaric acid, itaconic acid, etc. 2-10 Examples include alkenes and dicarboxylic acids.

[0090] These second dicarboxylic acid units (A2) may be used alone or in combination of two or more types.

[0091] The proportion of the fluoredicarboxylic acid unit (A1) can be selected in the range of, for example, 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total dicarboxylic acid unit (A), and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable not to substantially include the second dicarboxylic acid unit (A2). If the proportion of the fluoredicarboxylic acid unit (A1) is excessively low, there is a concern that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersion cannot be formed.

[0092] (Diol unit (B))

[0093] In a polyester resin, it is preferable that the diol unit (B) has a diol unit having a fluorene ring containing group (hereinafter also referred to as a fluorediol unit) (B1).

[0094] Fluorendiol unit (B1)

[0095] Fluorendiol units (B1) include diol units represented by the following formula (2).

[0096] [Chemical Formula 7]

[0097]

[0098] (during food, R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b represents a divalent hydrocarbon group that may each independently have a substituent, and A 1a and A 1b Each independently represents a straight-chain or branched-chain alkylene group, and n1 and n2 represent integers greater than or equal to 0).

[0099] In the above equation (2), R 2The substituent and the number of substituents m represented by include preferred embodiments such as specific groups, ranges of the number of substituents, and substitution positions, and R in the above formula (1). 1 It is identical to the substituent represented by and its number of substituents k, respectively.

[0100] X 2a and X 2b In this case, as a divalent hydrocarbon group, X in the above formula (1) 1a and X 1b Examples include divalent aliphatic hydrocarbon groups such as straight-chain or branched-chain alkylene groups, divalent alicyclic hydrocarbon groups such as cyclohexylene groups, and divalent aromatic hydrocarbon groups such as phenylene groups. Preferred divalent hydrocarbon groups include divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups.

[0101] X 2a and X 2b In this case, the substituents that the divalent hydrocarbon group may have may be non-reactive groups or non-polymerizable substituents that are inactive to the polymerization reaction, for example, a halogen atom, a hydrocarbon group (or group [-R h ]), Gi [-OR h ] (In the food, R h represents the above hydrocarbon group), group [-SR h ] (In the food, R h Examples include the hydrocarbon group), acyl group, nitro group, cyano group, mono or disubstituted amino group, etc.

[0102] Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

[0103] The above R h Examples of hydrocarbon groups represented by alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, etc.

[0104] As alkyl groups, for example, straight-chain or branched-chain C groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, and t-butyl groups 1-10 Examples include alkyl groups, preferably straight-chain or branched-chain C 1-6 Alkyl group, more preferably straight-chain or branched-chain type C 1-4 It is an alkyl group.

[0105] As cycloalkyl groups, for example, C such as cyclopentyl groups, cyclohexyl groups, etc. 5-10 Cycloalkyl groups can be cited.

[0106] As aryl groups, for example, C groups such as phenyl groups, alkylphenyl groups, biphenyl groups, and naphthyl groups 6-12 Examples of aryl groups include mono- to tri-C groups, such as methylphenyl groups (or tolyl groups) and dimethylphenyl groups (or xylyl groups). Alkylphenyl groups include, for example, mono- to tri-C groups. 1-4 An alkyl-phenyl group can be used.

[0107] As aralkyl groups, for example, C groups such as benzyl groups and phenethyl groups 6-10 Aryl-C 1-4 An alkyl group can be cited.

[0108] The above [-OR h Examples of ] include alkoxy groups, cycloalkyloxy groups, aryloxy groups, aralkyloxy groups, etc., and specifically, the hydrocarbon group R h Groups corresponding to the examples can be cited. As for alkoxy groups, for example, straight-chain or branched-chain C groups such as methoxy groups, ethoxy groups, propoxy groups, n-butoxy groups, isobutoxy groups, and t-butoxy groups can be cited. 1-10 Examples of alkoxy groups include cycloalkyloxy groups, for example, C such as cyclohexyloxy groups. 5-10 Examples of aryloxy groups include cycloalkyloxy groups. Examples of aryloxy groups include C groups such as phenoxy groups. 6-10 Examples of aryloxy groups include aryloxy groups. Aralkyloxy groups include, for example, C such as benzyloxy groups. 6-10 Aryl-C 1-4Alkylic oxygen groups can be cited.

[0109] The above [-SR h Examples of ] include alkylthio groups, cycloalkylthio groups, arylthio groups, aralkylthio groups, etc., and specifically, the hydrocarbon group R h Groups corresponding to the examples can be cited. As alkyl thio groups, for example, C groups such as methyl thio, ethyl thio, propyl thio, n-butyl thio, and t-butyl thio. 1-10 Examples of alkylthio groups include cycloalkylthio groups, for example, C such as cyclohexylthio groups. 5-10 Examples of arylthio groups include cycloalkylthio groups. Examples of arylthio groups include, for instance, C thiophenoxy groups. 6-10 Examples of arylthio groups include aralkylthio groups, for example, C such as benzylthio groups. 6-10 Aryl-C 1-4 Examples include alkylthio groups.

[0110] As for acyl groups, C such as acetyl groups 1-6 Examples include alkyl-carbonyl groups, etc.

[0111] Examples of mono- or di-substituted amino groups include dialkylamino groups, bis(alkylcarbonyl)amino groups, etc. Examples of dialkylamino groups include diC groups such as dimethylamino groups. 1-4 Examples of alkylamino groups include bis(alkylcarbonyl)amino groups, for example, bis(C) such as diacetylamino groups. 1-4 Examples include alkyl-carbonyl)amino groups.

[0112] X 2a and X 2b In this case, the number of substituents that the divalent hydrocarbon group may have may be selected from a range of, for example, 0 to 10, preferably 0 to 2, more preferably 0 or 1, and particularly 0.

[0113] X 2a and X 2b The types may differ from each other, but it is preferable that they be the same.

[0114] Alkylene group A 1a and A 1b For example, straight-chain or branched-chain C such as ethylene groups, propylene groups (1,2-propanediyl groups), trimethylene groups, 1,2-butanediyl groups, and tetramethylene groups. 2-6 Examples include alkylene groups, and when the number of repetitions n1 or n2 is 1 or more, preferably a straight-chain or branched-chain type C 2-4 Straight-chain or branched-chain type C, more preferably alkylene groups, ethylene groups, propylene groups, etc. 2-3 It is an alkylene group, and an ethylene group is particularly preferred.

[0115] Oxyalkylene group (-OA) 1a -) and (-OA 1b The repetition count (additional mole count) n1 and n2 of -) may each be 0 or greater, and can be selected from an integer range of, for example, 0 to 15, and the preferred range is, in steps below, 0 to 10, 0 to 8, 0 to 6, 0 to 4, 0 to 2, and 0 to 1. Also, X 2a and X 2b When is a divalent aliphatic hydrocarbon group such as a straight-chain or branched-chain alkylene group, the number of repetitions n1 or n2 is preferably 0, and X as in formula (2A) described below. 2a and X 2bIn the case where the valence group is an aromatic hydrocarbon group, the number of repetitions n1 and n2 are preferably 1 or more each in order to improve polymerization reactivity, and can be selected from an integer range of, for example, 1 to 15 each, and the preferred range is, in steps below, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, 1 to 2, and is particularly preferred to be 1. Furthermore, in this specification and claims, "number of repetitions (additional moles)" may be an average value (arithmetic mean, additional mean) or an average additional mole, and the preferred embodiment is the same as the preferred range (the range of integers above). If the number of repetitions n1 and / or n2 is excessively large, there is a risk that the refractive index or heat resistance will decrease.

[0116] Also, the two repetitions n1 and n2 may be the same or different from each other. If n1 or n2 is 2 or more, 2 or more oxyalkylene groups (-OA 1a -) or (-OA 1b The types of -) may be identical or different from each other. Also, X 2a and X 2b (Poly)oxyalkylene groups (-OA) bonded via ether bonds (-O-) 1a -) n1 and (-OA 1b -) n2 The types may be the same or different from each other.

[0117] Representative diol units represented by the above formula (2) include X 2a and X 2b Examples include a diol unit that is a straight-chain or branched-chain alkylene group (hereinafter also simply referred to as a bisalkylfluorediol unit) (B1-1), and a diol unit represented by formula (2A) described below (hereinafter also simply referred to as a bisarylfluorediol unit) (B1-2). These fluorediol units (B1) may be used alone or in combination of two or more types.

[0118] Bisalkylfluorediol unit (B1-1)

[0119] The bisalkylfluorediol unit (B1-1) is X 2a and X 2b Since the alkylene group is a straight-chain or branched-chain type aliphatic hydrocarbon group, in combination with the fluorene ring structure (fluorene-9,9-diyl group) of the side chain, similar to the case of the fluorene dicarboxylic acid unit represented by Formula (1) above, the wavelength dependence of the refractive index in the direction of the main chain is small, and the wavelength dependence of the refractive index in the direction orthogonal to the direction of the main chain is large, so it is easy to prepare a polyester resin with negative and net dispersion of orientation birefringence and also a large wavelength dependence. In addition, the phase difference expression is high, and it can be stretched under milder stretching conditions, and it is possible to form a film with excellent moldability and handling properties by improving toughness (flexibility) so that it is difficult to break, and it is desirable in that it can reduce thermal shrinkage due to residual stress, etc., so it is desirable in that it can form a thinner phase difference film.

[0120] In the bisalkylfluorediol unit (B1-1), the straight-chain or branched-chain alkylene group X 2a and X 2b For example, straight-chain or branched-chain C such as methylene groups, ethylene groups, trimethylene groups, propylene groups, 1,2-butanediyl groups, 2-methylpropane-1,3-diyl groups, etc. 1-8 Examples include alkylene groups, etc. Among these, preferably straight-chain or branched-chain C 1-6 An alkylene group, more preferably a straight-chain or branched-chain type C 1-4 It is an alkylene group, and more preferably a straight-chain or branched-chain type C 1-3 It is an alkylene group, and among them, C such as methylene groups, ethylene groups, etc. 1-2An alkylene group is preferred, and a methylene group is particularly preferred. In addition, among these alkylene groups, when n1 and / or n2 is 0, a straight-chain alkylene group is preferred in that it can suppress the reduction in polymerization reactivity caused by secondary alcohols.

[0121] Representative bisalkylfluorenediol units (B1-1) include 9,9-bis(hydroxymethyl)fluorene, 9,9-bis(2-hydroxyethyl)fluorene, 9,9-bis(3-hydroxypropyl)fluorene, 9,9-bis(4-hydroxybutyl)fluorene, etc., 9,9-bis(hydroxy) linear or branched chain type C 1-6 Examples include alkyl fluorene, etc.

[0122] These bisalkylfluorediol units (B1-1) may be used alone or in combination of two or more. Preferred bisalkylfluorediol units (B1-1) include 9,9-bis(hydroxy straight-chain type C 1-6 Alkyl)fluorene, more preferably 9,9-bis(hydroxy straight-chain type C 1-4 Alkyl)fluorene, more preferably 9,9-bis(hydroxy straight-chain type C 1-3 It is an alkyl)fluorene, and among them, 9,9-bis(hydroxy straight-chain type C 1-2 Alkyl)fluorene is preferred, and 9,9-bis(hydroxymethyl)fluorene is particularly preferred.

[0123] Bis-aryl fluorediol unit (B1-2)

[0124] The bis-arylfluorediol unit (B1-2) represented by the following formula (2A) has negative orientation birefringence of the polyester resin due to its cardo structure, and also has the effect of greatly increasing the wavelength dependence of net dispersion (the effect of making net wavelength dispersion steep). The bis-arylfluorediol unit (B1-2) is X of the above formula (2). 2a and X 2bIt corresponds to a unit that is an aromatic hydrocarbon group of 2, and the refractive index in the main chain direction and its wavelength dependence are relatively large. Although there is a concern that the effect of adjusting the aforementioned optical properties (phase difference expression and wavelength dispersion properties) or the moldability and handling properties derived from the toughness of the film may be slightly lower compared to the bisalkylfluorediol unit (B1-1), it is more preferable than the bisalkylfluorediol unit (B1-1) because it is easy to improve the glass transition temperature of the polyester resin, thereby reducing thermal shrinkage caused by residual stress and effectively improving environmental reliability (heat resistance and water resistance (moisture resistance), as well as dimensional stability and phase difference stability against heat and moisture). That is, the bisarylfluorediol unit (B1-2) is effective in adjusting the balance between phase difference expression and wavelength dispersion properties and environmental reliability. For this reason, the bis-aryl-fluorediol unit (B1-2) is preferably combined with the fluoredicarboxylic acid unit and / or the bis-alkyl-fluorediol unit (B1-1) represented by the above formula (1), and at least, it is more preferably combined with the fluoredicarboxylic acid unit represented by the above formula (1).

[0125] [Chemical Formula 8]

[0126]

[0127] (in food, Z 1a and Z 1b Each independently represents an Aren ring, and R 3a and R 3b ☐ each independently represents a substituent, p1 and p2 each independently represent an integer greater than or equal to 0, and R 2 , m, A 1a and A 1b , n1 and n2 are each identical to the above formula (2), including a preferred embodiment).

[0128] In the above equation (2A), Z 1a and Z 1bExamples of arene rings (aromatic hydrocarbon rings) represented by [the ring] include monocyclic arene rings such as the benzene ring, polycyclic arene rings, etc. Examples of polycyclic arene rings include condensed polycyclic arene rings (condensed polycyclic aromatic hydrocarbon rings), ring-assembled arene rings (ring-assembled polycyclic aromatic hydrocarbon rings), etc.

[0129] Examples of condensed polycyclic arene rings include, for instance, condensed dicyclic arene rings, condensed tricyclic arene rings, and condensed di- to tetracyclic arene rings. Examples of condensed dicyclic arene rings include, for instance, condensed dicyclic C rings such as naphthalene rings and indene rings. 10-16 Examples include arene rings. Condensed tricyclic arene rings include, for example, condensed tricyclic C rings such as anthracene rings and phenanthrene rings. 14-20 Examples include arene rings, etc. A desirable condensed polycyclic arene ring is a condensed polycyclic C such as a naphthalene ring. 10-14 It is Aren Gori.

[0130] Examples of ring-assemblies of arene rings include, for instance, birene rings such as biphenyl rings, phenylnaphthalene rings, and binafthyl rings; and terarene rings such as terphenyl rings. A preferred ring-assembly of arene rings is C such as a biphenyl ring. 12-18 It is a Viaren ring.

[0131] In addition, in the scope of this specification and claims, "ring assembly arene ring" means an arene ring in which two or more ring systems (arene ring systems) are directly connected by single bonds or double bonds, and the number of bonds connecting the rings is only one less than the number of ring systems. For example, as described above, non-irene rings such as biphenyl rings, phenylnaphthalene rings, and non-naphthyl rings are classified as ring assembly arene rings even if they have a condensed polycyclic arene ring backbone such as a naphthalene ring backbone. Therefore, "ring assembly arene rings" are clearly distinguished from "condensed polycyclic arene rings" such as naphthalene rings (non-ring assembly arene rings).

[0132] Desirable ring Z 1a and Z 1b Ro, C 6-14 Examples of arene rings include C, more preferably benzene rings, naphthalene rings, biphenyl rings, etc. 6-12 C, such as an arene ring, more preferably a benzene ring, a naphthalene ring, etc. 6-10 Arene ring, especially a benzene ring, is desirable.

[0133] Ring Z 1a and Z 1b The types may differ from each other, but it is preferable that they be the same. In addition, ring Z bonding to the 9 position of the fluorene ring. 1a and Z 1b The substitution positions are not particularly limited. For example, ring Z 1a If it is a benzene ring, it can be at any position, and ring Z 1a In the case where is a naphthalene ring, it is at either the 1st or 2nd position, preferably the 2nd position, and ring Z 1a If is a biphenyl ring, it is any of the 2, 3, or 4 positions, preferably the 3 position. Ring Z 1b The same applies to .

[0134] R 3a and R 3bThe substituent represented by is X of the above formula (2). 2a and X 2b In this case, the substituents exemplified as substituents that the divalent hydrocarbon group may have can be mentioned. These groups R 3a and R 3b In the middle, representative examples include halogen atoms; hydrocarbon groups such as alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups; alkoxy groups; acyl groups; nitro groups; cyano groups; and substituted amino groups. When the number of substitutions p1 and / or p2 is 1 or more, a preferred R 3a and / or R 3b Examples of groups include alkyl groups, cycloalkyl groups, aryl groups, and alkoxy groups, and more preferably, straight-chain or branched-chain C groups such as methyl groups. 1-6 C, such as alkyl groups, cyclohexyl groups, etc. 5-8 C such as cycloalkyl groups, phenyl groups, etc. 6-14 Straight-chain or branched-chain type C, such as aryl groups and methoxy groups 1-4 Examples include alkoxy groups. Among these, straight-chain or branched-chain C 1-4 Alkyl groups such as alkyl groups or aryl groups are preferred, and straight-chain or branched-chain type C 1-3 Alkyl group, C 6-10 An aryl group is more preferable, and C such as a methyl group is preferred. 1-2 An alkyl group and a phenyl group are more preferable. In addition, group R 3a When ga is an arylgi, gi R 3a is, ring Z 1a The above ring set Aren ring may be formed together with R. 3b and Z 1b The same applies to .

[0135] Gi R 3a and R 3b The permutation numbers p1 and p2 of are each integers greater than or equal to 0, and the ring Z 1a and Z 1bDepending on the type, it can be appropriately selected, for example, an integer of about 0 to 8, and the preferred range is, in steps below, an integer of 0 to 4, an integer of 0 to 3, and an integer of 0 to 2, among which 0 or 1 is preferred, and particularly 0 is preferred.

[0136] In addition, the substitution numbers p1 and p2 may be different from each other, but it is preferable that they be the same. Also, if the substitution number p1 is 2 or more, the same ring Z 1a R of 2 or more that is replaced by 3a The types of may be the same or different from each other. p2, Z 1b and R 3b The same applies to . Also, gi R 3a and R 3b The types of may differ from each other, but it is preferable that they be the same. In particular, when p1 is 1, ring Z 1a a benzene ring, naphthalene ring, or biphenyl ring, group R 3a g can be a methyl group. p2, Z 1b and R 3b The same applies to . Also, gi R 3a The substitution position of is not particularly restricted, and ring Z 1a And, the 9th position of the fluorene ring and the group [-O-(A 1a O) n1 -] (hereinafter also referred to as the ether-containing group) needs to be substituted at a position other than the binding position with the ring Z 1a In this case, it is preferable to substitute the ether-containing group at an ortho position (a carbon atom adjacent to the bonding position of the ether-containing group). R 3b , Z 1b and [-O-(A 1b O) n2 The same applies to -].

[0137] Gi [-O-(A 1a O) n1 -] ring Z 1aThe substitution positions for are not specifically limited, and ring Z 1a It is sufficient if it is substituted at a suitable position of. The substitution position of the above ether-containing group is ring Z 1a In the case where α is a benzene ring, it is preferable that any of the 2, 3, or 4 positions of the phenyl group bonded to the 9 position of the fluorene ring be substituted, among them, the 3 or 4 position, particularly the 4 position. Also, ring Z 1a In the case of this naphthalene ring, it is preferable that the ether-containing group is substituted at any of the 5 to 8 positions of the naphthyl group bonded to the 9 position of the fluorene ring; for example, it is preferable that the 1 or 2 positions of the naphthalene ring are substituted with respect to the 9 position of the fluorene ring (substituted in the relationship of 1-naphthyl or 2-naphthyl), and that the substituted positions are substituted in the relationship of 1,5-position, 2,6-position, etc., particularly in the relationship of 2,6-position. Also, ring Z 1a In the case where the ring assembly is an arene ring, the substitution position of the ether-containing group is not particularly limited and may be substituted, for example, with an arene ring bonded to the 9 position of fluorene or an arene ring adjacent to this arene ring. For example, ring Z 1a a biphenyl ring (or ring Z) 1a ga benzene ring, p1 is 1, R 3a In the case where α is a phenyl group), the 3rd or 4th position of the biphenyl ring may be bonded to the 9th position of the fluorene, and in the case where the 3rd position of the biphenyl ring is bonded to the 9th position of the fluorene, the substitution position of the ether-containing group may be, for example, any of the 2nd, 4th, 5th, 6th, 2', 3', or 4' positions of the biphenyl ring, and preferably substituted at the 6th position or the 4' position, particularly at the 6th position. [-O-(A 1b O) n2 -], Z 1b , p2 and R 3bThe same applies to .

[0138] Representative bis-aryl-fluorediol units (B1-2) include, for example, 9,9-bis(hydroxyaryl)fluorenes in which n1 and n2 are 0 in the above formula (2A); and diol units corresponding to 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes in which n1 and n2 are 1 or more, for example, about 1 to 10. Furthermore, in this specification and claims, unless otherwise specified, "(poly)alkoxy" is used to mean both an alkoxy group and a polyalkoxy group.

[0139] Examples of 9,9-bis(hydroxyaryl)fluorenes include 9,9-bis(hydroxyphenyl)fluorene, 9,9-bis(alkyl-hydroxyphenyl)fluorene, 9,9-bis(aryl-hydroxyphenyl)fluorene, 9,9-bis(hydroxynaphthyl)fluorene, etc.

[0140] Examples of 9,9-bis(hydroxyphenyl)fluorene include, for instance, 9,9-bis(4-hydroxyphenyl)fluorene.

[0141] 9,9-bis(alkyl-hydroxyphenyl)fluorenes include, for example, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-isopropylphenyl)fluorene, 9,9-bis(4-hydroxy-3,5-dimethylphenyl)fluorene, etc. 9,9-bis[(mono or di)C 1-4 Examples include alkyl-hydroxyphenyl]fluorene, etc.

[0142] As for 9,9-bis(aryl-hydroxyphenyl)fluorenes, for example, 9,9-bis(C 6-10 Examples include aryl-hydroxyphenyl)fluorene, etc.

[0143] Examples of 9,9-bis(hydroxynaphthyl)fluorene include 9,9-bis(6-hydroxy-2-naphthyl)fluorene, 9,9-bis(5-hydroxy-1-naphthyl)fluorene, etc.

[0144] Examples of 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes include 9,9-bis[hydroxy(poly)alkoxyphenyl]fluorene, 9,9-bis[alkyl-hydroxy(poly)alkoxyphenyl]fluorene, 9,9-bis[aryl-hydroxy(poly)alkoxyphenyl]fluorene, 9,9-bis[hydroxy(poly)alkoxynaphthyl]fluorene, etc.

[0145] 9,9-bis[hydroxy(poly)alkoxyphenyl]fluorenes include, for example, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)ethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxypropoxy)phenyl]fluorene, 9,9-bis[hydroxy(mono to deca)C 2-4 Examples include [alkoxyphenyl]fluorene, etc.

[0146] 9,9-bis[alkyl-hydroxy(poly)alkoxyphenyl]fluorenes include, for example, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)ethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, 9,9-bis[4-(2-hydroxypropoxy)-3-methylphenyl]fluorene, etc. 9,9-bis[(mono or di)C 1-4 Alkyl-hydroxy(mono to deca)C 2-4 Examples include [alkoxyphenyl]fluorene, etc.

[0147] As for 9,9-bis[aryl-hydroxy(poly)alkoxyphenyl]fluorenes, for example, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)-3-phenylphenyl]fluorene, 9,9-bis(4-(2-hydroxypropoxy)-3-phenylphenyl)fluorene, etc. 9,9-bis[C 6-10 Aryl-hydroxy(mono-to-deca)C 2-4 Examples include [alkoxyphenyl]fluorene, etc.

[0148] 9,9-bis[hydroxy(poly)alkoxynaphthyl]fluorenes include, for example, 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, 9,9-bis[5-(2-hydroxyethoxy)-1-naphthyl]fluorene, 9,9-bis[6-(2-hydroxyethoxy)ethoxy)-2-naphthyl]fluorene, 9,9-bis[6-(2-hydroxypropoxy)-2-naphthyl]fluorene, etc., 9,9-bis[hydroxy(mono to deca)C 2-4 Examples include [alkoxy-naphthyl]fluorene, etc.

[0149] These bis-arylfluorediol units (B1-2) may be included alone or in combination of two or more. Among the bis-arylfluorediol units (B1-2), preferably 9,9-bis[hydroxy(mono to hexa)C 2-4 Alkoxy C 6-10 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes such as aryl]fluorenes, more preferably 9,9-bis[hydroxy(mono or di)C 2-4 Alkoxy-C 6-10 aryl]fluorene, more preferably 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene, 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, etc. 9,9-bis[hydroxy C 2-3 Alkoxy-C 6-12aryl]fluorenes, among others, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, etc., 9,9-bis[hydroxy C 2-3 Constituent units derived from [alkoxy-phenyl]fluorene are preferred.

[0150] In the fluorediol unit (B1), the bisalkylfluorediol unit (B1-1) and the bisarylfluorediol unit (B1-2) may be used alone or in combination of two or more types. The ratio of the total amount of bisalkylfluorenediol units (B1-1) and bisarylfluorenediol units (B1-2) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total fluorenediol units (B1), and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and substantially, it is preferable that the fluorenediol units (B1) consist only of bisalkylfluorenediol units (B1-1) and / or bisarylfluorenediol units (B1-2). If the above ratio is excessively low, there is a concern that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersibility cannot be formed. In order to satisfy the balance between phase difference expression and wavelength dispersion characteristics and environmental reliability, it is preferable that the fluorediol unit (B1) contains only bisarylfluorediol units (B1-2).

[0151] In addition, the proportion of fluorediol units (B1) can be selected in a range of, for example, 1 mol% or more, specifically 10 to 100 mol% with respect to the total diol units (B), and the preferred range is, in steps below, 30 to 100 mol%, 50 to 99 mol%, 60 to 98 mol%, 70 to 97 mol%, and 80 to 96 mol%, and particularly 85 to 95 mol% is preferred. If the proportion of fluorediol units (B1) is too low, there is a risk that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersibility cannot be formed, and if it is too high, there is a risk that moldability or handling properties may be reduced.

[0152] (Poly)alkylene glycol unit (B2)

[0153] The polyester resin may, as a diol unit (B), include a (poly)alkylene glycol unit (B2) represented by the following formula (3) as needed. Including the (poly)alkylene glycol unit (B2) improves the polymerization reactivity of the polyester resin, thereby increasing the molecular weight, and improves toughness through a flexible chemical structure, making it effective for preparing a phase difference film with excellent moldability and handling properties. For this reason, it is preferable to combine it with a bis-aryl fluorediol unit (B1-2).

[0154] [Chemical Formula 9]

[0155]

[0156] (during food, A 2 represents a straight-chain or branched-chain alkylene group, and q represents an integer greater than or equal to 1).

[0157] In the above equation (3), A 2The alkylene groups represented by are, for example, straight-chain or branched-chain C groups such as ethylene, propylene, trimethylene, 1,2-butanediyl, 1,3-butanediyl, tetramethylene, 1,5-pentanediyl, 1,6-hexanediyl, 1,8-octanediyl, and 1,10-decanediyl groups. 2-12 Examples include alkylene groups, etc. A preferred alkylene group A 2 Ro, step by step below, straight chain type or branched chain type C 2-10 Alkylene group, straight-chain or branched-chain type C 2-8 Alkylene group, straight-chain or branched-chain type C 2-6 Alkylene group, straight-chain or branched-chain type C 2-4 It is an alkylene group, and more preferably a straight-chain or branched-chain type C such as an ethylene group or a propylene group. 2-3 It is an alkylene group, and an ethylene group is particularly preferred.

[0158] The number of repetitions q can be selected from a range of, for example, 1 to 10, and the preferred range is, stepwise as follows: 1 to 8, 1 to 6, 1 to 4, 1 to 3, 1 to 2, and particularly 1 is preferred. In addition, the number of repetitions q may be an average value (arithmetic mean or additive mean), and the preferred embodiment is the same as the above range of integers. When q is 2 or more, 2 or more oxyalkylene groups (-A 2 The types of O-) may differ from each other, but it is preferable that they be the same.

[0159] Examples of diol components corresponding to the (poly)alkylene glycol unit (B2) include alkylene glycol (or alkanediol), polyalkylene glycol (or polyalkanediol), etc.

[0160] As for the alkylene glycol, for example, in the above formula (3), q is 1, and A 2a. Compounds corresponding to the alkylene groups of the above examples, specifically, straight-chain or branched-chain C such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, tetramethylene glycol (or 1,4-butanediol), 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, etc. 2-12 Examples include alkylene glycol, etc., and a preferred embodiment is the above alkylene group A 2 It is identical to the corresponding.

[0161] As for the polyalkylene glycol, in the above formula (3), q is 2 or more, for example, 2 to 10, and A 2 a compound corresponding to the alkylene group of the above examples, specifically, a di to deca straight-chain or branched-chain type C such as diethylene glycol, dipropylene glycol, triethylene glycol, etc. 2-12 Examples include alkylene glycols, etc., preferably di to hexa linear or branched chain type C 2-6 Alkylene glycol, more preferably di to tetra straight-chain or branched-chain type C 2-4 An example is alkylene glycol.

[0162] These (poly)alkylene glycol units (B2) may be included alone or in combination of two or more types. A preferred (poly)alkylene glycol unit (B2) is a diol unit derived from alkylene glycol, which is difficult to reduce heat resistance, and more preferably a straight-chain or branched-chain type C 2-6 Straight-chain or branched-chain C of alkylene glycol, more preferably ethylene glycol, propylene glycol, 1,4-butanediol, etc. 2-4 Alkylene glycols, in particular, straight-chain or branched-chain C such as ethylene glycol and propylene glycol 2-3 Constituent units derived from alkylene glycol, particularly ethylene glycol, are preferred.

[0163] The proportion of (poly)alkylene glycol units (B2) can be selected in the range of 0 to 100 mol%, for example, 1 to 50 mol%, with respect to the total diol units (B). The preferred range is, in steps below, 3 to 30 mol%, 5 to 20 mol%, and 7 to 15 mol%, and is particularly preferred to be 8 to 12 mol%. If the proportion of (poly)alkylene glycol units (B2) is excessively high, there is a risk that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersibility cannot be formed, and if it is excessively low, there is a risk that moldability or handling properties may be reduced.

[0164] When combining a fluorediol unit (B1) and a (poly)alkylene glycol unit (B2), the ratio B1 / B2 (molar ratio) can be selected in a range of, for example, 1 / 99 to 99 / 1, and the preferred range is, in steps below, 10 / 90 to 99 / 1, 30 / 70 to 99 / 1, 50 / 50 to 99 / 1, 60 / 40 to 98 / 2, 70 / 30 to 97 / 3, 80 / 20 to 96 / 4, and particularly 85 / 15 to 95 / 5 is preferred. In particular, when combining bis-arylfluorediol units (B1-2) and (poly)alkylene glycol units (B2), the ratio B1-2 / B2 (molar ratio) is the same as the ratio of B1 / B2, including preferred embodiments. If the ratio of fluorediol units (B1) or bis-arylfluorediol units (B1-2) is too low, there is a risk that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersibility cannot be formed, and if it is too high, there is a risk that moldability or handling properties may be reduced.

[0165] 3rd Diol Unit (B3)

[0166] The polyester resin does not have to include a third diol unit (B3) that is different from the fluorediol unit (or first diol unit) (B1) and (poly)alkylene glycol unit (or second diol unit) (B2) as a diol unit (B), but may include it as needed as long as it does not impede the effects of the present disclosure.

[0167] Examples of the third diol unit (B3) include, for instance, alicyclic diols, aromatic diols [except for diols corresponding to the fluorediol unit (B1)], and constituent units derived from alkylene oxide (alkylene carbonate or haloalkanol) adducts of these diol components.

[0168] Examples of cycloaliphatic diols include, for instance, cycloalkanediols such as cyclohexanediol; bis(hydroxyalkyl)cycloalkanes such as cyclohexanedimethanol; hydrogenated aromatic diols such as hydrogenated bisphenol A, which will be exemplified later.

[0169] Examples of aromatic diols include dihydroxyalenes such as hydroquinone and resorcinol; aromatic aliphatic diols such as benzenedimethanol; bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol C, bisphenol G, and bisphenol S; and biphenols such as p,p'-biphenol.

[0170] As adducts of these diol components, alkylene oxide (corresponding alkylene carbonate or haloalkanol) include, for example, C 2-4 C of alkylene oxide adducts, preferably ethylene oxide adducts, propylene oxide adducts, etc. 2-3 Examples include alkylene oxide adducts, and the number of moles added is not particularly limited. Specifically, examples include adducts in which about 2 to 10 moles of ethylene oxide are added to 1 mole of a diol such as bisphenol A.

[0171] The diol unit (B) may include these third diol units (B3) alone or in combination of two or more types.

[0172] The ratio of the total amount of fluorediol units (B1) and (poly)alkylene glycol units (B2) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total amount of diol units (B), and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and in particular 100 mol%, and it is preferable not to substantially include the third diol unit (B3).

[0173] The polyester resin preferably comprises a fluoredicarboxylic acid unit (A1) and a fluorediol unit (B1) in that it is easy to adjust the orientation birefringence and wavelength dispersion characteristics, and more preferably comprises a fluoredicarboxylic acid unit (A1), a bisarylfluorediol unit (B1-2) and a (poly)alkylene glycol unit (B2).

[0174] In a polyester resin, the ratio of the total amount of constituent units having a fluorene ring containing group, namely the fluoredicarboxylic acid unit (A1) and the fluorediol unit (B1), can be selected in the range of, for example, 10 mol% or more, specifically 30 to 100 mol% with respect to the total constituent units of the polyester, and the preferred range is, in steps below, 50 to 100 mol%, 60 to 100 mol%, 70 to 100 mol%, 80 to 100 mol%, 90 to 99 mol%, and more preferably 92 to 98 mol%. If the ratio of constituent units having a fluorene ring containing group is excessively low, there is a risk that a polyester resin exhibiting negative orientation birefringence and net wavelength dispersibility cannot be formed.

[0175] Additionally, the resin does not have to include other constituent units (C) that are different from the dicarboxylic acid unit (A) and the diol unit (B), but may include them as necessary to the extent that they do not impede the effects of the present disclosure. Examples of other constituent units (C) may be constituent units derived from, for instance, hydroxyalkanoic acids or corresponding lactones, polyfunctional polymeric components having three or more carboxyl groups and / or hydroxyl groups, carbonate bond-forming components, etc.

[0176] The above hydroxyalkano acids or corresponding lactones include, for example, C of lactic acid, 3-hydroxybutyric acid, 6-hydroxyhexanoic acid, etc. 2-10 Examples include hydroxyalkano acids; lactones corresponding to hydroxyalkano acids such as ε-caprolactone.

[0177] Examples of the above-mentioned polyfunctional polymer components include polycarboxylic acids with three or more valent carboxylic acids such as trimellitic acid and pyromellitic acid, polyhydric alcohols with three or more valent carboxylic acids such as glycerin and pentaerythritol, and polyfunctional polymer components having a total of three or more carboxyl groups and / or hydroxyl groups.

[0178] As for the carbonate bond-forming component, it is sufficient to have a compound capable of forming a carbonate bond through a reaction with two diol components. That is, the "constituent unit derived from the carbonate bond-forming component" refers to a carbonyl group, which forms a carbonate bond together with the terminal oxygen atoms of two diol units bonded adjacent to this carbonyl group. Representative carbonate bond-forming components include, for example, phosgenes such as phosgene and triphosgene, and carbonate diesters such as diphenyl carbonate.

[0179] The proportion of such other constituent units (C) is, for example, 50 mol% or less with respect to the total amount of constituent units (total amount of dicarboxylic acid unit (A), diol unit (B) and other constituent units (C)), preferably in a stepwise range of 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, and 5 mol% or less, and preferably does not substantially contain other constituent units (C). In addition, the above proportion may be about 0 to 10 mol%, for example, 0.01 to 1 mol%.

[0180] (Manufacturing method and characteristics of polyester resins)

[0181] The above method for manufacturing the polyester resin may utilize conventional methods depending on the type of resin or other polymerization components (copolymerization components), etc. For example, when the polyester resin is a polyester resin, it may be manufactured by reacting a dicarboxylic acid component (A) corresponding to each of the aforementioned dicarboxylic acid units, etc. with a diol component (B) corresponding to the aforementioned diol units, etc., and may be prepared using conventional methods, specifically melt polymerization methods such as ester exchange method, direct polymerization method, solution polymerization method, interfacial polymerization method, etc., and melt polymerization method is preferred. In addition, the reaction may be carried out in the presence or absence of a solvent depending on the polymerization method.

[0182] The usage ratio (or injection ratio) of the dicarboxylic acid component (A) and the diol component (B) may be the former / the latter (molar ratio) =, for example, 1 / 1.2 to 1 / 0.8, preferably 1 / 1.1 to 1 / 0.9, but it is not necessary to be within this range, and at least one component selected from each dicarboxylic acid component (A) and each diol component (B) may be used in excess of the planned introduction ratio to be reacted. For example, a (poly)alkylene glycol component (B2), such as ethylene glycol that can be discharged from the reaction system, may be used in excess of the ratio (or introduction ratio) introduced into the resin.

[0183] The reaction may be carried out in the presence of a catalyst. Conventional esterification catalysts, such as metal catalysts, may be used as catalysts. As metal catalysts, metal compounds including, for example, alkali metals such as sodium; alkaline earth metals such as magnesium, calcium, and barium; transition metals such as titanium, manganese, and cobalt; Group 12 metals such as zinc and cadmium; Group 13 metals such as aluminum; Group 14 metals such as germanium and lead; and Group 15 metals such as antimony are used. As metal compounds, for example, alkoxides; organic salts such as acetates and propionates; inorganic salts such as borates and carbonates; oxides, etc., may be used, or they may be hydrates. Representative metal compounds include, for example, germanium compounds such as germanium dioxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, and germanium-n-butoxide; Examples include antimony compounds such as antimony trioxide, antimony acetate, and antimony ethylene glycol; titanium compounds such as tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate (titanium (IV) tetrabutoxide), titanium oxalate, and potassium titanium oxalate; manganese compounds such as manganese acetate tetrahydrate; and calcium compounds such as calcium acetate monohydrate.

[0184] These catalysts may be used individually or in combination of two or more. When multiple catalysts are used, each catalyst may be added as the reaction progresses. Among these catalysts, manganese acetate tetrahydrate, calcium acetate monohydrate, germanium dioxide, titanium (IV) tetrabutoxide, etc. are preferred. The amount of catalyst used is, for example, 0.01 × 10⁻⁶ per 1 mole of dicarboxylic acid component (A). -4 ~ 100 × 10 -4 Moles, preferably 0.1 × 10⁻⁶ -4 ~ 40 × 10 -4 It is a mall.

[0185] Additionally, the reaction may be carried out in the presence of stabilizers, such as heat stabilizers or antioxidants, if necessary. Typically, heat stabilizers are commonly used, and examples include phosphorus compounds such as trimethylphosphate, triethylphosphate, triphenylphosphate, dibutylphosphate (dibutyl phosphate or dibutyl phosphate), phosphoric acid, trimethylphosphite, and triethylphosphite. Among these, dibutyl phosphate is commonly used. The amount of heat stabilizer used is, for example, 0.01 × 10⁻³ per 1 mole of dicarboxylic acid component (A). -4 ~ 100 × 10 -4 Moles, preferably 0.1 × 10⁻⁶ -4 ~ 40 × 10 -4 It is a mall.

[0186] The reaction may be carried out in an atmosphere of an inert gas, for example, nitrogen gas; or noble gases such as helium, argon, etc. In addition, the reaction may be carried out under reduced pressure, for example, 1 × 10⁻⁶ 2 ~ 1 × 10 4It may also be carried out at approximately Pa. It is preferable to carry out the ester exchange reaction under an inert gas atmosphere such as nitrogen gas, and it is preferable to carry out the polycondensation reaction under reduced pressure. The reaction temperature can be selected according to the polymerization method, for example, the reaction temperature in the melt polymerization method is 150 to 320 ℃, preferably 180 to 310 ℃, more preferably 200 to 300 ℃.

[0187] The glass transition temperature Tg of the polyester resin obtained in this way may be in the range of, for example, 80 to 250°C, and the preferred range is, in steps below, 100 to 200°C, 110 to 170°C, 110 to 160°C, 115 to 150°C, 120 to 140°C, and 120 to 130°C. If the glass transition temperature is excessively high, moldability may be reduced and melt film formation may become difficult, and if it is excessively low, environmental reliability (heat resistance and water resistance (moisture resistance), dimensional stability against heat or moisture and phase difference stability) may be reduced, and reliability (or durability) under a humid heat environment may be reduced even after mounting on an image display device.

[0188] In addition, as described below, when forming a phase difference film as a multilayer film (laminated film), it is desirable to adjust the glass transition temperature of the polyester resin to near the glass transition temperature of the polyamide resin so that moldability can be effectively improved.

[0189] The weight average molecular weight Mw of the polyester resin can be measured by gel penetration chromatography (GPC), etc., and can be selected in a range of, for example, 20,000 to 150,000 in terms of polystyrene. The preferred range is, in steps below, 25,000 to 120,000, 30,000 to 100,000, 35,000 to 90,000, 40,000 to 80,000, 45,000 to 75,000, 50,000 to 70,000, and 55,000 to 65,000. If the weight average molecular weight is excessively low, moldability such as film formation and stretchability is reduced, and there is a risk that the film may break due to stretching, etc., or that handling ability may be reduced due to insufficient mechanical strength of the film. If the weight-average molecular weight is excessively large, the melt viscosity becomes excessively high, which may lead to a decrease in moldability.

[0190] In addition, in the scope of this specification and claims, the glass transition temperature Tg and weight average molecular weight Mw can be measured by the method described in the examples below.

[0191] [Polyamide resin]

[0192] The polyamide resin may be a resin that exhibits positive orientation birefringence in its single film (uniaxially stretched film) and also exhibits flat dispersion in phase difference. The polyamide resin may have a chemical structure containing at least an amide bond (or amide group) in its main chain, and examples include polyamide resin, polyamideimide resin, and polyesteramide resin. These polyamide resins may be included individually or in combination of two or more types. Among these polyamide resins, polyamide resin is preferred in terms of moldability and phase difference expression.

[0193] Polyamide resins exhibiting the above characteristics include, for example, polyamide resins comprising a constituent unit having a cycloaliphatic backbone (or acycloaliphatic hydrocarbon group), and preferably, polyamide resins comprising a constituent unit having a cycloaliphatic backbone on the main chain.

[0194] Conventionally, cyclic olefin copolymers (COPs) are used as resins having a cyclic backbone in phase difference films. COPs have flat dispersibility and typically have low phase difference expression. Although phase difference expression (ease of phase difference expression) can be improved by introducing an aromatic cyclic backbone into the chemical structure, it is very difficult to achieve both high phase difference expression and flat dispersibility because the wavelength dispersion characteristics change significantly from flat dispersibility to pure wavelength dispersibility.

[0195] However, the inventors have discovered that in a polyamide resin having a cycloidal framework, a surprisingly high phase difference expression and flat dispersion can be achieved, possibly because the amide group present in the main chain can improve the phase difference without significantly changing the wavelength dispersion characteristics in the direction of net dispersion. Furthermore, when combined with the aforementioned polyester resin, a high phase difference expression and reverse wavelength dispersion can be achieved, and in particular, a phase difference film with excellent balance of thinness, phase difference, and reverse wavelength dispersion can be formed while improving moldability (or productivity) and environmental reliability.

[0196] In addition, the aliphatic backbone may be an aliphatic hydrocarbon ring (a hydrocarbon ring that is non-aromatic or does not have an aromatic ring), and may include multiple bonds such as double bonds within the ring, but it is preferable not to include multiple bonds. Aliphatic hydrocarbon rings can be broadly classified into monocyclic aliphatic hydrocarbon rings and cross-linked aliphatic hydrocarbon rings.

[0197] Examples of monocyclic aliphatic hydrocarbon rings include, for instance, cycloalkane rings and cycloalkene rings. Examples of cycloalkane rings include, for instance, cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, cyclooctane rings, etc. 3-20 Examples include cycloalkane rings. Cycloalkene rings include C such as the cyclopentene ring and the cyclohexene ring. 3-20 Examples include cycloalkene rings.

[0198] Examples of cross-linked cyclic aliphatic hydrocarbon rings include, for instance, cross-linked cycloalkane rings and cross-linked cycloalkene rings. Examples of cross-linked cycloalkane rings include C decalin rings, norbornane rings, adamantane rings, tricyclodecane rings, tetracyclododecane rings, etc. 7-20 Examples include non-tetracycloalkane rings, etc. As for tricyclodecane rings, tricyclo[5.2.1.0 2,6 Examples include ]decane rings, etc. As for tetracyclododecane rings, tetracyclo[4.4.0.1 2,5 .1 7,10 Examples include the dodecane ring, etc. As cross-linked cycloalkene rings, C such as the norbornene ring, tricyclodecene ring, and tetracyclododecene ring can be cited. 7-20 Examples include non-tetracycloalkene rings.

[0199] The constituent unit having a cyclic skeleton may include these cyclic skeletons alone or in combination of two or more types in its chemical structure. Among these cyclic skeletons, a cycloalkane ring that does not contain multiple bonds or a cross-linked cycloalkane ring is preferred, a monocyclic cycloalkane ring is preferred from the perspective of flat dispersibility, and more preferably C 5-10 It is a cycloalkane ring, and among them, C such as a cyclohexane ring 5-8 A cycloalkane ring is desirable.

[0200] Polyamide resins can be formed by the polymerization of a diamine component and a dicarboxylic acid component, the polymerization of an aminocarboxylic acid component and / or a lactam component, the polymerization of a diamine component and a dicarboxylic acid component with an aminocarboxylic acid component and / or a lactam component, etc., and depending on the form, at least one of the polymerization components forming the polyamide resin may have a cycloaliphatic backbone. Accordingly, the polyamide resin may be formed by including at least one polymerization component selected from the cycloaliphatic diamine component, the cycloaliphatic dicarboxylic acid component, and the cycloaliphatic aminocarboxylic acid component described below, and as a representative polyamide resin, it is preferable that the polymerization component includes a diamine component (D) and a dicarboxylic acid component (E), and that at least the diamine component has a cycloaliphatic backbone.

[0201] (Diamine unit (D))

[0202] cycloaliphatic diamine unit (D1)

[0203] The diamine unit (D) preferably comprises an alicyclic diamine unit (D1) having an alicyclic skeleton. As the alicyclic diamine unit (D1), it is sufficient to be a diamine unit having the alicyclic skeleton of the above example in its chemical structure, for example, C such as cyclohexanediamine. 5-10 Bis(amino C) such as cycloalkandiamine and bis(aminomethyl)cyclohexane 1-4 Alkyl)C 5-10 It may be a diamine unit derived from cycloalkanes, etc., but it is preferable to include at least a diamine unit represented by the following formula (4).

[0204] [Chemical Formula 10]

[0205]

[0206] (during food, Y 1 represents a divalent hydrocarbon group that may be directly bonded or have a substituent, and R 4a and R 4bEach represents a substituent independently, and r1 and r2 each represent an integer from 0 to 4 independently).

[0207] In the above equation (4), Y 1 It is preferable that the divalent hydrocarbon group be a direct bond, but may also have a substituent. The divalent hydrocarbon group may be a divalent aromatic hydrocarbon group such as a phenylene group, but from the perspective of flat dispersibility, a divalent alicyclic hydrocarbon group such as a cyclohexylene group or a divalent aliphatic hydrocarbon group is preferred, and a divalent aliphatic hydrocarbon group is particularly preferred.

[0208] Y 1 The divalent aliphatic hydrocarbon groups represented by are, for example, straight-chain or branched-chain alkenylene groups, specifically, straight-chain or branched-chain C groups such as vinylene groups, 1-methylvinylene groups, propphenylene groups, 1-butenylene groups, 2-butenylene groups, 1-pentenylene groups, 2-pentenylene groups, etc. 2-20 Alkenylene group; straight-chain or branched-chain alkylene groups, specifically, straight-chain or branched-chain C such as ethynylene group, propynylene group, 3-methyl-1-propynylene group, butylene group, 2-pentynylene group, 2-hexynylene group, 3-heptynylene group, 4-octynylene group, 4-nonynylene group, 5-decynylene group, 6-undecynylene group, 6-dodecynylene group, etc. 2-20 Alkynylene group; straight-chain or branched-chain alkadi to trinylene group, specifically, 1,3-butadiylene group, 2,4-pentadiylene group, 1,3,5-hexatrinylene group, etc., but it is preferable that it be a straight-chain or branched-chain alkylene group.

[0209] Y 1 The straight-chain or branched-chain alkylene groups represented by are, for example, straight-chain or branched-chain C such as methylene groups, ethylene groups, methylmethylene groups (ethylidene groups), propylene groups, trimethylene groups, propane-2,2-diyl groups (dimethylmethylene groups), etc. 1-20Examples include alkylene groups, etc., and preferably, stepwise below, straight-chain or branched-chain type C 1-10 Alkylene group, straight-chain or branched-chain type C 1-6 Alkylene group, straight-chain or branched-chain type C 1-4 Alkylene group, straight-chain or branched-chain type C 1-3 Alkylene group, straight-chain or branched-chain type C 1-2 It is an alkylene group, and a methylene group is more preferable.

[0210] Also, Y 1 Examples of substituents that the divalent hydrocarbon group represented by may have include aryl groups such as phenyl groups, cycloalkyl groups such as cyclohexyl groups, etc. The number of substituents is not particularly limited and is, for example, 0 to 10, preferably 0 to 2, more preferably 0 or 1, particularly 0. Examples of divalent hydrocarbon groups having substituents may include 1-phenylethylene groups, 1-phenylpropane-1,2-diyl groups, etc. Also, Y 1 It is preferable that the silver be a straight-chain or branched-chain alkylene group without substituents.

[0211] R 4a and R 4b The substituent represented by may be a non-reactive group inactive to the polymerization reaction or a non-polymerizable substituent, for example, X of the above formula (2). 2a and X 2b In this case, substituents that may be possessed by the divalent hydrocarbon group include groups identical to the exemplified groups. Among these substituents, alkyl groups are preferred, and more preferably, straight-chain or branched-chain C groups such as methyl groups, ethyl groups, propyl groups, and isopropyl groups. 1-5 Alkyl group, more preferably straight-chain or branched-chain type C 1-4 It is an alkyl group, and among them, a straight-chain or branched-chain type C 1-3 An alkyl group is preferred, and in particular, a straight-chain or branched-chain type C such as a methyl group. 1-2An alkyl group is preferred.

[0212] R 4a and R 4b The permutation numbers r1 and r2 may each be selected from an integer range of, for example, 0 to 3, preferably 0 to 2, more preferably 0 or 1, among which 0 is preferred, and particularly preferred that both r1 and r2 are 0. When r1 is 2 or more, R of 2 or more 4a The types of may be the same or different, respectively. r2 and R 4b The same applies to . Also, R substituted with a different cyclohexane ring 4a and R 4b The types may be the same or different from each other.

[0213] Representative diamine units represented by the above formula (4) include constituent units derived from bis(aminocyclohexyl)alkanes, for example, bis(aminocyclohexyl)C such as bis(4-aminocyclohexyl)methane and 2,2-bis(4-aminocyclohexyl)propane. 1-6 Alkanes; bis(4-amino-3-methylcyclohexyl)methane, bis(4-amino-3,5-dimethylcyclohexyl)methane, 2,2-bis(4-amino-3-cyclohexyl)propane, etc. bis(amino-mono to tri-C 1-6 Alkyl-cyclohexyl)C 1-6 Examples of constituent units derived from alkanes include

[0214] These diamine units represented by the above formula (4) may be used alone or in combination of two or more types. Among these diamine units represented by the above formula (4), a constituent unit derived from bis(aminocyclohexyl)alkanes is preferred, and more preferably bis(aminocyclohexyl)C 1-4 Alkanes, more preferably bis(aminocyclohexyl)C 1-3 Alkanes, among them, bis(aminocyclohexyl)C such as bis(4-aminocyclohexyl)methane 1-2Constituent units derived from alkanes are preferred.

[0215] The cycloaliphatic diamine unit (D1) may be included alone or in combination of two or more types. In the cycloaliphatic diamine unit (D1), the ratio of the diamine unit represented by the above formula (4) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total cycloaliphatic diamine unit (D1). The preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable that the cycloaliphatic diamine unit (D1) substantially consists only of the diamine unit represented by the above formula (4). If the above ratio is excessively low, there is a risk that a polyamide resin exhibiting positive orientation birefringence and flat dispersibility cannot be formed.

[0216] Second diamine unit (D2)

[0217] The polyamide resin does not have to include a diamine unit (second diamine unit (D2)) that is different from the alicyclic diamine unit (or first diamine unit) (D1) as a diamine unit (D), but may include it as needed as long as it does not impede the effects of the present disclosure.

[0218] The second diamine unit (D2) may be a constituent unit derived from, for example, an aliphatic diamine component, an aromatic (or aromatic aliphatic) diamine component, etc.

[0219] As for aliphatic diamine components, for example, straight-chain or branched-chain C such as tetramethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, 2-methyloctamethylenediamine, trimethylhexamethylenediamine, decamethylenediamine, and dodecamethylenediamine 2-20 Examples include alkylenediamines.

[0220] As aromatic (or aromatic aliphatic) diamine components, for example, diaminoalene, specifically diaminoC such as m-phenylenediamine, p-phenylenediamine, etc. 6-14 Arene; bis(aminoalkyl)arene, specifically, bis(aminoC) such as m-xylylenediamine 1-4 Examples include alkyl arenes, etc.

[0221] These second diamine units (D2) may be used alone or in combination of two or more types.

[0222] The proportion of the cycloaliphatic diamine unit (D1) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total diamine unit (D). The preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable that the diamine unit (D) substantially comprises only the cycloaliphatic diamine unit (D1). If the above proportion is excessively low, there is a concern that a polyamide resin exhibiting positive orientation birefringence and flat dispersibility cannot be formed.

[0223] (Dicarboxylic acid unit (E))

[0224] The dicarboxylic acid unit (E) may or may not include the alicyclic dicarboxylic acid unit (E2) described later, but it is preferable to include the aliphatic dicarboxylic acid unit (E1).

[0225] Aliphatic dicarboxylic acid unit (E1)

[0226] Including an aliphatic dicarboxylic acid unit (E1) allows the glass transition temperature Tg of the polyamide resin to be adjusted to an appropriate range, making it easier to improve moldability. Therefore, when combined with a constituent unit having a cycloaliphatic backbone, such as the aforementioned cycloaliphatic diamine unit (D1), moldability can be effectively improved even if the unit has a cycloaliphatic backbone.

[0227] The aliphatic dicarboxylic acid component forming the aliphatic dicarboxylic acid unit (E1) is Y of the above formula (4). 1 Examples include dicarboxylic acid components in which two carboxyl groups are bonded to the two aliphatic hydrocarbon groups specifically exemplified as such.

[0228] These aliphatic dicarboxylic acid components may be used alone or in combination of two or more. Among these aliphatic dicarboxylic acid components, straight-chain or branched-chain alkanedicarboxylic acid components are preferred. Examples of straight-chain or branched-chain alkanedicarboxylic acid components include straight-chain or branched-chain C such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, souveric acid, azelaic acid, sebacic acid, and 1,10-decandicarboxylic acid. 1-20 Examples include alkane-dicarboxylic acid components, and preferably straight-chain or branched-chain C such as adipic acid, sebacic acid, and 1,10-decandicarboxylic acid. 4-16 Alkane-dicarboxylic acid component, more preferably straight-chain or branched-chain type C 6-14 It is an alkane-dicarboxylic acid component, in particular, a straight-chain or branched-chain type C such as 1,10-decanedicarboxylic acid 8-12 Alkandicarboxylic acid components are preferred. Additionally, among straight-chain or branched-chain alkandicarboxylic acid components, straight-chain alkandicarboxylic acid components are preferred.

[0229] The proportion of the aliphatic dicarboxylic acid unit (E1) can be selected in the range of, for example, 1 mol% or more, specifically 10 to 100 mol% with respect to the total dicarboxylic acid unit (E), and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable that the dicarboxylic acid unit (E) substantially consists only of the aliphatic dicarboxylic acid unit (E1). If the above proportion is excessively low, there is a risk that moldability will be reduced.

[0230] cycloaliphatic dicarboxylic acid unit (E2)

[0231] The dicarboxylic acid unit (E) does not necessarily have to include a dicarboxylic acid alicyclic unit (E2), and for example, if the diamine unit (D) includes a diamine alicyclic unit (D1), it does not have to include it, but if necessary, it may include it as a constituent unit having a dicycloidal framework.

[0232] Examples of dicarboxylic acid units (E2) include dicarboxylic acid units having one or more of the aforementioned aliphatic hydrocarbon rings exemplified as dicarboxylic backbones. The dicarboxylic backbones may be present alone or in combination of two or more types, and if present in multiples, the dicarboxylic backbones may be directly bonded to each other or Y in the above formula (4). 1 It may be bonded by interposing divalent aliphatic hydrocarbon groups, etc., as specifically exemplified. In addition, the above alicyclic skeleton may have substituents, for example, alkyl groups, etc., and specifically, C such as methyl groups. 1-6 It may have an alkyl group.

[0233] Representative alicyclic dicarboxylic acid units (E2) may include constituent units derived from the alicyclic dicarboxylic acid component specifically exemplified as the second dicarboxylic acid unit (A2) above. These alicyclic dicarboxylic acid units (E2) may be included alone or in combination of two or more types. Preferred alicyclic dicarboxylic acid units (E2) may include cycloalkanedicarboxylic acids, and more preferably C such as 1,4-cyclohexanedicarboxylic acid. 5-10 It is a cycloalkane-dicarboxylic acid.

[0234] 3rd dicarboxylic acid unit (E3)

[0235] The polyamide resin does not have to include a dicarboxylic acid unit (E3) that is different from an aliphatic dicarboxylic acid unit (or a first dicarboxylic acid unit) (E1) and a dicycloaliphatic diamine unit (or a second dicarboxylic acid unit) (E2) as a dicarboxylic acid unit (E), but may include it as needed as long as it does not impede the effects of the present disclosure.

[0236] As the tertiary dicarboxylic acid unit (E3), constituent units derived from aromatic dicarboxylic acid components, for example, can be cited. As aromatic dicarboxylic acid components, C aromatic hydrocarbon rings, for example, benzene rings, naphthalene rings, anthracene rings, fluorene rings, etc. 6-20 Examples include a dicarboxylic acid component substituted with two carboxyl groups for an aromatic hydrocarbon ring. Additionally, the aromatic dicarboxylic acid component may have one or more of the above aromatic hydrocarbon rings, or may have them alone or in combination of two or more types. In the case of having multiple rings, the aromatic hydrocarbon rings may be directly bonded to each other or Y in the above formula (4). 1It may be bonded by interposing the divalent aliphatic hydrocarbon group or the divalent alicyclic hydrocarbon group, etc., as specifically exemplified. In addition, the above aromatic hydrocarbon ring backbone may have substituents, for example, alkyl groups, cycloalkyl groups, etc., and specifically, C such as methyl groups. 1-6 C, such as alkyl groups, cyclohexyl groups, etc. 3-6 It may have cycloalkyl groups, etc.

[0237] Representative aromatic dicarboxylic acid components include the aromatic dicarboxylic acid components specifically exemplified as the second dicarboxylic acid unit (A2), such as benzenedicarboxylic acid components like isophthalic acid and terephthalic acid.

[0238] These third dicarboxylic acid units (E3) may be included alone or in combination of two or more types.

[0239] The ratio of the total amount of aliphatic dicarboxylic acid units (E1) and alicyclic dicarboxylic acid units (E2) can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total dicarboxylic acid units (E). The preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, and it is preferable that the dicarboxylic acid units (E) substantially comprise only aliphatic dicarboxylic acid units (E1) and / or alicyclic dicarboxylic acid units (E2). If the above ratio is excessively low, there is a risk that moldability will be reduced or that a polyamide resin exhibiting positive orientation birefringence and flat dispersibility cannot be formed.

[0240] (Aminocarboxylic acid (or lactam) unit (F))

[0241] The polyamide resin may or may not contain an aminocarboxylic acid (or corresponding lactam) unit (F).

[0242] cycloaliphatic aminocarboxylic acid unit (F1)

[0243] The aminocarboxylic acid unit (F) may or may not include a cycloaliphatic aminocarboxylic acid unit (F1). As for the cycloaliphatic aminocarboxylic acid unit (F1), for example, an aminocycloalkanecarboxylic acid component, specifically, an amino C such as aminocyclohexanecarboxylic acid. 5-10 Examples of constituent units derived from cycloalkanes and carboxylic acid components include these. These cycloaliphatic aminocarboxylic acid units (F1) may be included alone or in combination of two or more types.

[0244] 2-aminocarboxylic acid unit (F2)

[0245] The polyamide resin does not have to include an aminocarboxylic acid unit (second aminocarboxylic acid unit) (F2) that is different from a cycloaliphatic aminocarboxylic acid unit (or first aminocarboxylic acid unit) (F1) as an aminocarboxylic acid unit (F), but may include it as needed as long as it does not impede the effects of the present disclosure.

[0246] The second aminocarboxylic acid unit (F2) may be a constituent unit derived from, for example, an aliphatic aminocarboxylic acid component (or the corresponding lactam component), an aromatic aminocarboxylic acid component, etc.

[0247] Aliphatic aminocarboxylic acid components include, for example, amino C such as 6-aminohexanoic acid, 11-aminoundecanic acid, and 12-aminododecanoic acid. 2-20 Examples include alkylcarboxylic acid components, etc., and preferably amino C 4-16 Alkylcarboxylic acid component, more preferably amino C 5-11It is an alkylcarboxylic acid component. In addition, corresponding lactam components include, for example, 4- to 12-membered ring lactams such as ε-caprolactam and ω-laurolactam, and preferably 7- to 12-membered ring lactams.

[0248] Examples of aromatic aminocarboxylic acid components include aminoarenecarboxylic acids such as aminobenzoic acid.

[0249] These 2-aminocarboxylic acid units (F2) may be included alone or in combination of two or more types.

[0250] The ratio of the total amount of diamine units (D) and dicarboxylic acid units (E) forming the polyamide resin can be selected, for example, in the range of 1 mol% or more, specifically 10 to 100 mol% or more with respect to the total number of constituent units of the polyamide resin, and the preferred range is, in the following steps, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and particularly 100 mol%, it is preferable that the polyamide resin substantially comprises only diamine units (D) and dicarboxylic acid units (E).

[0251] In addition, the polyamide resin may include at least a constituent unit having a cycloaliphatic backbone, and the ratio of the total amount of the cycloaliphatic diamine unit (D1), the cycloaliphatic dicarboxylic acid unit (E2), and the cycloaliphatic aminocarboxylic acid unit (F1) can be selected in the range of, for example, 1 mol% or more, specifically 10 to 100 mol% with respect to the total constituent unit of the polyamide resin, and the preferred range is, in steps below, 15 to 90 mol%, 20 to 80 mol%, 30 to 70 mol%, 40 to 60 mol%, and more preferably 45 to 55 mol%. If the above ratio is too low, there is a risk that a polyamide resin exhibiting positive orientation birefringence and flat dispersibility cannot be formed, and if it is too high, there is a risk that moldability will be reduced.

[0252] A preferred polyamide resin is a polyamide resin comprising a diaminoglycan unit (D1) and an aliphatic dicarboxylic acid unit (E1); more preferably, a polyamide resin comprising a diamine unit represented by the formula (4) and a constituent unit derived from a straight-chain or branched-chain alkanedicarboxylic acid component; and even more preferably, a constituent unit derived from a bis(aminocyclohexyl)alkane and a straight-chain or branched-chain C 4-16 It is a polyamide resin comprising constituent units derived from an alkane-dicarboxylic acid component; among them, bis(aminocyclohexyl)C 1-4 Constituent units derived from alkanes and straight-chain or branched-chain C 8-12 A polyamide resin comprising constituent units derived from an alkanedicarboxylic acid component is preferred; in particular, bis(aminocyclohexyl)C such as bis(4-aminocyclohexyl)methane 1-3 Constituent units derived from alkanes and straight-chain C such as 1,10-decanedicarboxylic acids 8-12 A polyamide resin containing constituent units derived from an alkane dicarboxylic acid component is preferred.

[0253] Polyamide resins may be manufactured by known methods or commercially available products may be used. Examples of commercially available products include "Trogamid CX7323" manufactured by Daicel Evonik Inc., "Grillamide TR90" manufactured by M.Chemical Inc., "Rylsan G350" and "Rylsan G850" manufactured by Arkema.

[0254] The glass transition temperature Tg of the polyamide resin may be in the range of, for example, 80 to 250°C, and the preferred range is, in steps below, 100 to 200°C, 110 to 170°C, 115 to 150°C, 120 to 145°C, 125 to 140°C, and 130 to 135°C. If the glass transition temperature is excessively high, moldability may be reduced, making melt film formation difficult, and if it is excessively low, environmental reliability (heat resistance and water resistance (moisture resistance), dimensional stability against heat or moisture and phase difference stability) may be reduced, and reliability (or durability) under a humid heat environment may be reduced even after mounting on an image display device.

[0255] In addition, as described below, when forming a phase difference film as a multilayer film (laminated film), it is desirable to adjust the glass transition temperature of the polyamide resin to near the glass transition temperature of the polyester resin so that moldability can be effectively improved.

[0256] The weight average molecular weight Mw of a polyamide resin can be measured by gel permeation chromatography (GPC) or the like, and can be selected in the range of, for example, 20,000 to 100,000 in terms of polystyrene equivalent. If the weight average molecular weight is excessively low, moldability such as film formation and stretchability is reduced, and there is a risk that the film may break due to stretching or that handling properties may be reduced due to insufficient mechanical strength. If the weight average molecular weight is excessively high, the melt viscosity becomes excessively high, and there is a risk that moldability will be reduced.

[0257] [Phase difference film]

[0258] (composition)

[0259] The phase difference film may include at least the polyester resin and polyamide resin, and may include one or more other conventional thermoplastic resins, etc., as long as they do not interfere with the effects of the present disclosure, but it is preferable not to include them. The proportion of the other conventional thermoplastic resin is, for example, 30 mass% or less, preferably 10 mass% or less, and more preferably 0 to 5 mass% with respect to the total amount of the polyester resin and polyamide resin.

[0260] In addition, the phase difference film may contain various additives as long as they do not interfere with the effects of the present disclosure. Examples of additives include plasticizers such as esters, phthalate compounds, epoxy compounds, and sulfonamides; flame retardants such as inorganic flame retardants, organic flame retardants, and colloidal flame retardant materials; stabilizers such as antioxidants, UV absorbers, and heat stabilizers; antistatic agents; fillers such as oxide-based inorganic fillers, non-oxide-based inorganic fillers, and metal powders; foaming agents; defoaming agents; lubricants; release agents such as natural waxes, synthetic waxes, straight-chain fatty acids or their metal salts, and acid amides; slip-improving agents, specifically inorganic fine particles such as silica, titanium oxide, calcium carbonate, clay, mica, and kaolin; organic fine particles such as (meth)acrylic resins and (crosslinked) styrene resins; and compatibilizers. These additives may be used alone or in combination of two or more types. These additives may be added by conventional methods, for example, by melt-kneading using a uniaxial or twin-axial extrusion device. The total ratio of the additives is, for example, 30 mass% or less, preferably 10 mass% or less, and more preferably 0 to 5 mass% with respect to the total amount of the polyester resin and polyamide resin.

[0261] The phase difference film may be a single-layer film comprising the polyester resin and the polyamide resin, but it is preferable to be a multilayer film (or laminated film). In the case of a multilayer film, the polyester resin and the polyamide resin may be included in the same layer of the multilayer film, but from the perspective of environmental reliability or ease of adhesion in lamination with other optical elements (or optical films) such as polarizers, it is preferable to have a laminated film having a first layer (polyester resin layer) comprising the polyester resin and a second layer (polyamide resin layer) comprising the polyamide resin, in which each resin is included in a separate layer.

[0262] In addition, regarding the first layer, the proportion of the polyester resin may be selected in a range of, for example, 1 mass% or more, specifically 10 to 100 mass% or more with respect to the total resin components forming the first layer, and the preferred range is, in the following steps, 30 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, and more preferably 100 mass%, and it is preferable that the resin components in the first layer substantially comprise only the polyester resin. In addition, the proportion of the polyamide resin in the second layer (the proportion with respect to the total resin components forming the second layer) also includes the same preferred embodiment corresponding to the proportion of the polyester resin in the first layer, and it is preferable that the resin components in the second layer substantially comprise only the polyamide resin.

[0263] In addition, in the case of a multilayer film, the phase difference film may include at least one layer of each of the first and second layers, and may include a plurality of first layers and / or a plurality of second layers. Also, if necessary, the phase difference film may include a third layer that does not include a polyester-based resin and a polyamide-based resin, or may not include one.

[0264] In the case of a multilayer film, the number of layers may be selected in a range of, for example, 2 to 10 layers, and the preferred range is, in stages below, 2 to 8 layers, 2 to 6 layers, 2 to 4 layers, 2 to 3 layers, and more preferably 3 layers.

[0265] In the case of a three-layer structure, a three-layer structure (two types of three-layer structure) in which skin layers formed of the same type of resin are laminated on both sides of a core layer located in the center is preferred, and it is even more preferable to have a three-layer structure in which the thickness (average thickness) of the skin layers on both sides is approximately the same. In a multilayer film, if there is a difference in shrinkage force after molding between the resins forming each layer, there is a risk that the multilayer film will curl and its handling properties will be reduced; however, by adopting the aforementioned three-layer structure, the difference in shrinkage force between the skin layers on both sides is offset, so that the curling of the phase difference film after molding can be effectively suppressed.

[0266] In the case of a three-layer structure, the core layer may be formed as the first layer (polyester-based resin layer) and the skin layers on both sides as the second layer (polyamide-based resin layer), but a three-layer structure in which the first layer as the skin layer is formed on both sides of the second layer as the core layer is preferred. By placing the second layer formed of a polyamide-based resin with a high absorption rate inside as the core layer and placing the polyester-based resin layer on the outside as the skin layer, the environmental reliability (dimensional stability and phase difference stability) against moisture (or under a humid and hot environment) can be effectively improved. In addition, when used in a laminate with other optical elements such as a polarizer (or polarizing plate), if the skin layer (outermost layer) is a polyester-based resin layer, it is preferable in terms of ease of adhesion. In particular, even when laminated with a polarizer formed of a PVA film with low water resistance, if the skin layer is a polyester-based resin layer, the degradation of the optical properties of the polarizer can be effectively suppressed.

[0267] Since the phase difference film is formed by combining a predetermined polyester-based resin and a predetermined polyamide-based resin, it is possible to achieve both excellent (or appropriate) reverse wavelength dispersion and a high phase difference. That is, a phase difference film exhibiting the desired phase difference and reverse wavelength dispersion can be formed thinner even in the form of a multilayer film. Accordingly, the film thickness (average thickness) of the phase difference film may be, for example, about 20 to 70 μm, and the preferred range is, in steps below, 25 to 60 μm, 30 to 60 μm, 30 to 50 μm, and 30 to 45 μm, and more preferably 30 to 40 μm. In addition, in the scope of this specification and claims, the film thickness (average thickness) can be measured by the method described in the examples described below.

[0268] If the film thickness is excessively thin, the winding properties during the film-making process are poor (making it prone to wrinkling, tearing, or difficulty in winding), and there is a risk that it may not be wound stably, as well as a risk of breakage during the stretching process. If it is excessively thick, there is a risk that it may not be able to meet the requirements for thinning phase difference films. Furthermore, if it is excessively thick, when stress is generated due to shrinkage or other factors in a humid and hot environment, an excessive load is placed on the film, causing a significant change in the phase difference and a risk of degrading optical properties (degrading environmental reliability). Additionally, when used in combination with a polarizer (or polarizing plate), warping is likely to occur due to drying during the lamination process, and there is a risk of degrading the optical properties of the polarizer.

[0269] When the phase difference film is a multilayer film comprising a first layer and a second layer, the ratio of the total thickness of the first layer (the sum of the average thicknesses of each first layer) to the total thickness of the second layer (the sum of the average thicknesses of each second layer) may be selected, for example, within the range of the former / the latter = 0.1 / 1 to 100 / 1, specifically 0.3 / 1 to 50 / 1, and the preferred range is, stepwise below, 0.5 / 1 to 30 / 1, 0.7 / 1 to 20 / 1, 0.9 / 1 to 15 / 1, 1 / 1 to 10 / 1, 1.3 / 1 to 8 / 1, 1.5 / 1 to 7 / 1, and 1.8 / 1 to 6 / 1, and when preparing the 1 / 4 wave plate described later, more preferably 2 / 1 to 5 / 1 It is, more preferably 2 / 1 to 4.5 / 1, and when preparing a phase difference film for a VA-LCD described later, it is more preferably 2 / 1 to 5.5 / 1, and more preferably 2.2 / 1 to 5 / 1.

[0270] In addition, since the ratio of the total thickness of the first layer to the total thickness of the second layer in the phase difference film (stretched film) is often equivalent to that of the laminated film (base film or unstretched film) before stretching, the ratio may be the ratio of the base film. If the total thickness of the first layer is excessively thin relative to the total thickness of the second layer, there is a risk that excellent reverse wavelength dispersion will not be obtained, and if it is excessively thick, there is a risk that reverse wavelength dispersion will not be obtained. Also, if the thickness of the first layer is excessively thick, there is a risk that a quarter-wave plate cannot be prepared.

[0271] (Manufacturing method, characteristics, and uses)

[0272] A phase difference film can be prepared by undergoing at least a film-forming process for forming the polyester resin and the polyamide-based resin, and a stretching process for stretching the raw film obtained from the film-forming process.

[0273] Examples of film formation methods include casting (solution casting or solution fluidization), extrusion, and calendering. Examples of extrusion methods include melt extrusion methods such as inflation and T-die methods. From the perspective of not only having excellent moldability but also preventing the degradation of optical properties due to residual solvent, melt extrusion methods such as T-die methods are preferred.

[0274] In addition, when the phase difference film is a multilayer film, the first layer containing the polyester resin and the second layer containing the polyamide resin may be formed and stretched separately and then laminated, but from the perspective of moldability (or productivity), it is preferable to co-stretch the laminated film (base film) obtained by co-extrusion. In this method, not only can the forming and stretching processes for each layer and the lamination process for each layer be omitted, but defects (lamination defects) caused by misalignment of the optical axis of each layer can also be effectively reduced.

[0275] Representative film-making methods by co-extrusion include drying each resin in pellet form so that the moisture content is, for example, less than 100 ppm, then weighing and mixing each resin pellet and additive and supplying them to an extruder, combining each molten resin using a slit-shaped die (T-die), and then melt-extruding from the die into a sheet to form a raw film.

[0276] The melting temperature of each resin in the extruder above is preferably set to, for example, Tg + 50 to Tg + 180°C with respect to the glass transition temperature Tg of each resin, and more preferably to Tg + 80 to Tg + 150°C. If the melting temperature in the extruder is excessively low, there is a risk of insufficient fluidity of the resin, and conversely, if the melting temperature is excessively high, there is a risk of the resin deteriorating.

[0277] Each resin melted by the extruder may be continuously supplied to the die via a filter, gear pump, etc., as needed, or high-precision filtration may be performed to effectively remove foreign substances contained in each molten resin. The filter material used for high-precision filtration of the molten resin is not particularly limited, but a filter material made of sintered stainless steel is preferred because it has excellent removal performance.

[0278] Examples of slit-shaped dies (T-dies) include multi-manifold dies and feed block dies. In terms of precisely controlling the layer thickness, a multi-manifold die designed to match the viscosity of each resin is preferred.

[0279] The average thickness (total thickness) of the base film (laminated film obtained by co-extrusion) obtained in the film-making process may be selected from a range of, for example, 10 to 1000 μm, and the preferred range is, in steps below, 20 to 500 μm, 30 to 200 μm, 40 to 170 μm, 50 to 150 μm, 60 to 140 μm, 70 to 130 μm, 75 to 125 μm, and 80 to 120 μm. If the average thickness of the base film is excessively thick, there is a concern that the phase difference film cannot be sufficiently thinned, and if the average thickness is excessively thin, there is a concern that the windability is poor (difficult to wind), that it cannot be wound stably, and that it may break during the stretching process, etc. In addition, the average thickness can be measured by the method described in the examples described below.

[0280] In the stretching process, each resin film obtained from the film-making process may be stretched, but as mentioned above, from the perspective of moldability, it is preferable to co-stretch the co-extruded film obtained from the film-making process.

[0281] In the case of the performance, it is desirable that the difference in glass transition temperature Tg between each resin, in particular the difference in Tg between the polyester resin and the polyamide resin, be small. Therefore, the difference in Tg between the polyester resin and the polyamide resin may be adjusted to a range of, for example, 0 to 30°C, and the preferred range is, in steps below, 0 to 20°C, 0 to 15°C, 0 to 10°C, 0 to 8°C, and 0 to 5°C. If the difference in Tg is within such a range, it is easy to form a phase difference film with desired characteristics even in a multilayer film, and it can be made into a thin film.

[0282] In detail, stretching conditions such as stretching temperature, stretching speed, and stretching ratio in a performance film are typically determined based on the results of stretching experiments on each layer (single film). That is, stretching conditions are examined to obtain desired characteristics when each single film is superimposed, based on characteristics such as phase difference, wavelength dispersion characteristics, and thickness of each layer's single film stretched under the same stretching conditions. However, if the difference in glass transition temperature Tg between each resin is excessively large, the range of stretching conditions that can be adjusted to the desired characteristics becomes narrow, which may lead to a decrease in moldability (or productivity), an inability to mold to the desired characteristics, or difficulty in stretching in the first place.

[0283] In addition, in the scope of this specification and claims, the difference in Tg in the case where the polyester resin and the polyamide resin are included in total of three or more types means the difference between the resin exhibiting the maximum Tg and the resin exhibiting the minimum Tg.

[0284] In addition, common methods for stretching include, for example, inter-roll stretching, heated roll stretching, compression stretching, tenter stretching, etc., and it may be uniaxial stretching or biaxial stretching.

[0285] These stretching methods and stretching conditions, such as stretching temperature, stretching ratio, and stretching speed, can be appropriately selected depending on the characteristics or applications required for the phase difference film. For example, when preparing a wave plate such as a quarter wave plate, particularly a broadband quarter wave plate used in organic EL displays, uniaxial stretching may be used. Also, when preparing a phase difference film for VA-LCDs, biaxial stretching may be used.

[0286] (1 / 4 wave plate)

[0287] For uniaxial stretching, it may be fixed-end uniaxial stretching, which maintains or fixes the length in the direction (width direction) within the film plane perpendicular to the stretching direction (or suppresses neck-in (shrinkage)), or free-end uniaxial stretching, which stretches without applying stress in the film width direction. Among these, fixed-end uniaxial stretching, which is tenter stretching, is preferred because it has a small neck-in and allows for easy adjustment of physical properties.

[0288] In addition, the stretching direction in uniaxial stretching may be longitudinal stretching that stretches nearly parallel to the film length direction, transverse stretching that stretches in a vertical width direction, or inclined stretching that stretches in an inclined direction forming a predetermined angle with respect to the film length direction. Among these, inclined stretching is preferred, and the angle formed by the direction of the ground axis (the axis where the refractive index is maximum within the film plane) (stretching direction) with respect to the film length direction may be selected in a range of, for example, about 30 to 60°, preferably 35 to 55°, more preferably 40 to 50°, even more preferably 42 to 48°, particularly about 45°. In this way, the phase difference film that has been inclined and stretched can be easily adjusted so that the ground axis is at an angle of 45° with respect to the absorption axis of the polarizer when laminated to a polarizer such as a linear polarizer in a roll-to-roll manner. Therefore, when manufacturing a circular polarizer, there is no need to laminate in a batch manner by cutting and laminating, which is particularly desirable in terms of excellent moldability (or productivity).

[0289] The stretching temperature is the minimum value among the Tg of all resin components included in each layer. min When set as, for example, Tg min - 10 ∼ Tg min + 20 ℃, in a preferred range, stepwise below, Tg min - 5 ∼ Tg min + 17 ℃, Tg min ~ Tg min+ 15 ℃, Tg min + 3 ~ Tg min + 13 ℃, Tg min + 5 ~ Tg min + 11 ℃, Tg min + 6 ~ Tg min + 10 ℃, Tg min + 7 ~ Tg min The specific temperature is + 9 ℃. Specific temperatures are, for example, 117 to 147 ℃, and preferred ranges are, in steps below, 122 to 144 ℃, 127 to 142 ℃, 130 to 140 ℃, 132 to 138 ℃, 133 to 137 ℃, and 134 to 136 ℃. If the stretching temperature is excessively high, not only is it difficult to achieve the desired phase difference, but the film cannot be stretched uniformly, and the film thickness becomes non-uniform. If the stretching temperature is excessively low, not only is it difficult to achieve the desired phase difference, but there is also a risk that the film may break.

[0290] The stretching ratio may be selected in a range of, for example, 1.1 to 10 times, and the preferred range is, in steps below, 1.3 to 8 times, 1.5 to 6 times, 1.8 to 5 times, 2 to 4 times, 2 to 3 times, and more preferably 2.2 to 2.8 times. If the stretching ratio is excessively low, there is a risk that the desired phase difference may not be obtained. However, the phase difference film of the present disclosure has high phase difference expression properties and is easy to adjust to the desired phase difference even in a thin film. On the other hand, if the stretching ratio is excessively high, there is a risk that the phase difference may become excessively high or the film may break, and there is a risk that the residual stress of the film will increase, causing the phase difference to change due to shrinkage of the film under a humid heat environment. However, since the phase difference film of the present disclosure has high phase difference expression properties and can be adjusted to the desired phase difference even when stretched under relatively mild conditions, the change in phase difference accompanied by shrinkage can be effectively suppressed. In addition, it has excellent formability or elongation, and because it possesses toughness even when formed into a thin film, the film is difficult to break.

[0291] The stretching speed (elongation rate / min) may be selected in a range of, for example, 50 to 600 % / min, preferably 100 to 500 % / min, and more preferably 200 to 400 % / min. In addition, in this specification and claims, elongation rate is defined as (length after stretching - length before stretching) / length before stretching × 100 [%]. If the stretching speed is excessively fast, there is a risk that the film may break. If the stretching speed is excessively low, there is a risk that the desired phase difference may not be obtained.

[0292] In addition, a preheating treatment may be performed before stretching and / or a heat-setting treatment may be performed after stretching. By these treatments, the deviation of the phase difference after stretching can be reduced, and the deviation of the orientation angle (the angle formed between the film length direction and the ground axis (or orientation axis)) associated with bowing (a phenomenon in which the ground axis (or orientation axis) becomes non-uniform (arched) in the width direction due to deformation) can be reduced. Either the preheating treatment or the heat-setting treatment may be performed, but it is preferable to perform both. It is preferable to perform these treatments by gripping with a clip (or tenter), and it is particularly preferable to perform them continuously with the stretching process.

[0293] In the preheating treatment, regarding the heating temperature, the minimum value among the Tg of all resin components included in each layer is Tg min When set as, for example, Tg min - 10 ∼ Tg min It may be selected within a range of approximately +20 ℃, and preferably Tg min + 7 ~ Tg min It is + 9 ℃, and it is preferable that it be the same temperature as the stretching temperature. The preheating time may be selected in a range of, for example, 1 second to 20 minutes, preferably 1 to 15 minutes, and more preferably 5 to 12 minutes.

[0294] In the heat-setting treatment, regarding the heating temperature, the minimum value among the Tg of all resin components included in each layer is Tg min When set as, for example, Tg min - 5 ∼ Tg min + 25 ℃, preferably Tg min ~ Tg min It is + 15 ℃. In addition, the heating temperature may be lower than the stretching temperature, for example, a temperature about 1 to 50 ℃ lower than the stretching temperature, preferably a temperature 2 to 40 ℃ lower, and more preferably a temperature 3 to 30 ℃ lower. In addition, the heating temperature is lower than the stretching temperature, and also Tg min It is particularly desirable that it be less than or equal to this. The heat setting processing time may be selected in a range of, for example, 1 second to 10 minutes, preferably 5 seconds to 4 minutes, and more preferably 10 seconds to 2 minutes. When heat setting, it is desirable to reduce the width of the tenter by about 0 to 10 percent relative to the width after the end of stretching.

[0295] As described above, when a quarter-wave plate is formed by uniaxial stretching, the in-plane phase difference at wavelength λ nm is Ro (λ), and the Ro (550) of the phase difference film may be, for example, about 100 to 170 nm, and preferably, in steps below, 110 to 160 nm, 120 to 155 nm, 125 to 150 nm, 130 to 145 nm, and 133 to 143 nm.

[0296] Also, Ro(450) / Ro(550) may be, for example, 0.7 or more and less than 1, and the preferred range is, in steps below, 0.75 to 0.95, 0.8 to 0.9, and 0.81 to 0.87.

[0297] In addition, for an ideal broadband quarter-wave plate, Ro (550) is 137.5 nm and Ro (450) / Ro (550) is approximately 0.818, and the closer Ro (550) and Ro (450) / Ro (550) are to the above ideal values, the better the broadband quarter-wave plate can be. Among the characteristics of in-plane phase difference Ro (550), dispersion Ro (450) / Ro (550), and thickness (thinness), it is particularly important that the in-plane phase difference Ro (550) is close to the ideal value.

[0298] Additionally, in the scope of this specification and claims, Ro (550) and Ro (450) / Ro (550) can be measured by the method described in the embodiments below.

[0299] (Phase difference film for VA-LCD)

[0300] A phase difference film (optical compensation film) for VA-LCD can be prepared by biaxial stretching. Biaxial stretching may be simultaneous biaxial stretching in which stretching occurs simultaneously in the longitudinal and transverse directions, or sequential biaxial stretching in which stretching occurs in one direction at a time. In addition, it may be equal stretching in which the stretching ratios in the longitudinal and transverse directions are equal, or uniaxial stretching in which the stretching ratios are different.

[0301] As a desirable biaxial stretching method, sequential biaxial stretching can be cited because it allows for easy adjustment of stretching conditions, resulting in excellent formability, and also enables suppression of deviations in the ground axis within the film surface. In sequential biaxial stretching, longitudinal stretching in the film length direction and transverse stretching in the film width direction may be performed discontinuously (the film is wound up after stretching in one direction and provided for stretching in the other direction), but it is preferable to perform continuous stretching for the sake of formability (or productivity). Specific stretching methods include the methods described above, and it is preferable that longitudinal stretching be roll-to-roll stretching or tenter stretching, and transverse stretching be tenter stretching.

[0302] The order of longitudinal stretching and transverse stretching is not particularly limited, but it is preferable to perform transverse stretching after longitudinal stretching, and it is even more preferable to perform transverse stretching after longitudinal stretching under stretching conditions stronger than those of longitudinal stretching (stretching conditions in which molecular chains are more oriented and the phase difference is higher). In such sequential biaxial stretching, it is preferable because the ground axis within the film plane (the direction in which the refractive index is maximum within the film plane) can be formed to form an angle approximately perpendicular to the film length direction, for example, 80 to 100°, preferably 85 to 95°.

[0303] In detail, as described above, the phase difference film for VA-LCD is positioned between a liquid crystal cell and a linear polarizer (linear polarizing film) positioned above and below it, and specifically, is used in a stacked form such that the ground axis within the film plane of the phase difference film is approximately perpendicular to the absorption axis of the linear polarizer. Typically, since the linear polarizer is positioned to have an absorption axis in the film length direction, stacking it with a phase difference film in which the ground axis is approximately perpendicular to the film length direction as described above allows for roll-to-roll lamination, which is advantageous in terms of formability (or productivity).

[0304] The stretching temperature may be the same or different for longitudinal and transverse stretching. The stretching temperature is the minimum value among the Tg of all resin components included in each layer, Tg min When set as, for example, Tg min - 10 ∼ Tg min + 30 ℃, in a preferred range, stepwise below, Tg min ~ Tg min + 20 ℃, Tg min + 5 ~ Tg min + 15 ℃, Tg min + 7 ~ Tg min + 13 ℃, Tg min + 8 ~ Tg min + 12 ℃, Tg min + 9 ~ Tg minThe temperature is + 11 ℃. Specific temperatures are, for example, 117 to 157 ℃, and preferred ranges are, in steps below, 127 to 147 ℃, 132 to 142 ℃, 134 to 140 ℃, 135 to 139 ℃, and 136 to 138 ℃. If the stretching temperature is excessively high, not only is it difficult to achieve the desired phase difference, but the film cannot be stretched uniformly, and there is a risk that the film thickness will become non-uniform. If the stretching temperature is excessively low, not only is it difficult to achieve the desired phase difference, but there is also a risk that the film will break.

[0305] The stretching ratio may be the same for longitudinal stretching and transverse stretching, but it is preferable that they be different, and it is even more preferable that the stretching ratio of transverse stretching is greater than that of longitudinal stretching. The stretching ratio of longitudinal stretching (or stretching in the MD direction (or film length direction)) may be selected in a range of, for example, 1.1 to 10 times, and the preferred range is, in steps below, 1.2 to 2.5 times, 1.3 to 2.3 times, 1.4 to 2.1 times, 1.5 to 2 times, 1.6 to 1.9 times, and more preferably 1.7 to 1.8 times. The stretching ratio for transverse stretching (or stretching in the TD direction (or film width direction)) may be selected in a range of, for example, 1.1 to 10 times, and the preferred range is, in steps below, 1.5 to 5 times, 1.8 to 3.5 times, 2 to 3 times, 2.1 to 2.8 times, 2.2 to 2.6 times, and more preferably 2.3 to 2.5 times. If the stretching ratio is excessively low, there is a risk that the desired phase difference may not be obtained. However, the phase difference film of the present disclosure has high phase difference expression properties, so it is easy to adjust to the desired phase difference even if it is a thin film. On the other hand, if the stretching ratio is excessively high, there is a risk that the phase difference may become excessively high or the film may break, and there is a risk that the residual stress of the film will increase, and the phase difference may change due to shrinkage of the film under a humid heat environment. However, the phase difference film of the present disclosure has high phase difference expression properties, and since it can be adjusted to a desired phase difference even when stretched under relatively mild conditions, changes in phase difference due to shrinkage can be effectively suppressed. In addition, it has excellent formability or stretchability, and since it possesses toughness even when formed into a thin film, the film is unlikely to break.

[0306] The stretching speed (elongation rate / min) may be the same or different for longitudinal and transverse stretching. The stretching speed (elongation rate / min) for longitudinal stretching may be selected in a range of, for example, 50 to 600 % / min, preferably 100 to 500 % / min, and more preferably 200 to 400 % / min. The stretching speed (elongation rate / min) for transverse stretching may be selected in a range of, for example, 50 to 600 % / min, preferably 100 to 500 % / min, and more preferably 200 to 400 % / min. If the stretching speed is excessively fast, there is a risk that the film may break. If the stretching speed is excessively low, there is a risk that the desired phase difference may not be obtained.

[0307] In addition, a preheating treatment may be performed before stretching and / or a heat-setting treatment may be performed after stretching. By these treatments, the deviation of the phase difference after stretching can be reduced, and the deviation of the orientation angle (the angle formed between the film length direction and the ground axis (or orientation axis)) associated with bowing (a phenomenon in which the ground axis (or orientation axis) becomes non-uniform (arched) in the width direction due to deformation) can be reduced. Either the preheating treatment or the heat-setting treatment may be performed, but it is preferable to perform both. It is preferable to perform these treatments by gripping with a clip (or tenter), and it is particularly preferable to perform them continuously with the stretching process.

[0308] In the preheating treatment, regarding the heating temperature, the minimum value among the Tg of all resin components included in each layer is Tg min When set as, for example, Tg min - 10 ∼ Tg min It may be selected within a range of approximately +30 ℃, and preferably Tg min + 9 ~ Tg minIt is + 11 ℃, and it is preferable that it be the same temperature as the stretching temperature. The preheating time may be selected in a range of, for example, 1 second to 20 minutes, preferably 1 to 15 minutes, and more preferably 5 to 12 minutes.

[0309] In the heat-setting treatment, regarding the heating temperature, the minimum value among the Tg of all resin components included in each layer is Tg min When set as, for example, Tg min - 5 ∼ Tg min + 25 ℃, preferably Tg min ~ Tg min It is + 15 ℃. In addition, the heating temperature may be lower than the stretching temperature, for example, a temperature about 1 to 50 ℃ lower than the stretching temperature, preferably a temperature 2 to 40 ℃ lower, and more preferably a temperature 3 to 30 ℃ lower. In addition, the heating temperature is lower than the stretching temperature, and also Tg min It is particularly desirable that it be less than or equal to this. The heat setting processing time may be selected in a range of, for example, 1 second to 10 minutes, preferably 5 seconds to 4 minutes, and more preferably 10 seconds to 2 minutes. When heat setting, it is desirable to reduce the width of the tenter by about 0 to 10 percent relative to the width after the end of stretching.

[0310] When a phase difference film for a VA-LCD is formed by biaxial stretching as described above, when the in-plane phase difference at wavelength λ nm is Ro (λ), the Ro (550) of the phase difference film for a VA-LCD may be, for example, about 20 to 65 nm, and preferably, in steps below, 25 to 60 nm and 30 to 55 nm.

[0311] The Ro (450) / Ro (550) of the phase difference film for VA-LCD may be, for example, 0.7 or more and less than 1, and the preferred range is, in steps below, 0.75 to 0.95, 0.78 to 0.93, 0.8 to 0.92, 0.81 to 0.91, and 0.818 to 0.9.

[0312] Also, when the phase difference in the thickness direction at wavelength λ nm is Rth (λ), Rth (589) may be, for example, about 100 to 160 nm, and the preferred range is, in steps below, 110 to 150 nm, 115 to 145 nm, 120 to 140 nm, and 125 to 135 nm.

[0313] In addition, for a phase difference film for VA-LCD, particularly for TV applications, among the characteristics of in-plane phase difference Ro (550), dispersibility Ro (450) / Ro (550), thickness direction phase difference Rth (589), and thickness (thinness), Ro (550), Ro (450) / Ro (550), and Rth (589) are of high importance, and in particular, it is considered most important that Ro (550) and Rth (589) are within the above-mentioned preferred range.

[0314] Additionally, in the scope of this specification and claims, Ro (550), Ro (450) / Ro (550) and Rth (589) can be measured by the method described in the embodiments below.

[0315] Examples

[0316] The present disclosure is described in more detail below based on examples, but the present disclosure is not limited by these examples. Details of the evaluation method and raw materials are described below.

[0317] [Evaluation Method]

[0318] (Glass transition temperature Tg)

[0319] A differential scanning calorimeter ("DSC6220" manufactured by Seiko Instruments Co., Ltd.) was used, and a sample was placed in an aluminum pan. Tg was measured in a range from 30°C to 200°C at a heating rate of 10°C / min under a nitrogen gas atmosphere.

[0320] (Molecular weight)

[0321] Gel penetration chromatography (manufactured by Tosho Corp., “HLC-8120GPC”) was used, and the sample was dissolved in chloroform to measure the weight average molecular weight Mw in terms of polystyrene.

[0322] (In-plane phase difference Ro and thickness direction phase difference Rth)

[0323] Using a retardation measuring device ("RETS-100" manufactured by Otsuka Electronics Co., Ltd.), the in-plane phase difference Ro (450) at a wavelength of 450 nm and the in-plane phase difference Ro (550) at a wavelength of 550 nm of the stretched film were each measured as actual values ​​at the thickness of each sample at a measurement temperature of 20 ℃, and from the obtained results, Ro (450) was divided by Ro (550) to calculate Ro (450) / Ro (550). In addition, the phase difference Rth (589) in the thickness direction at a wavelength of 589 nm of the stretched film was also measured using the same device.

[0324] (Average thickness)

[0325] Using a weather gauge ("Micrometer" manufactured by Mitutoyo Corp.), multiple points were measured at predetermined intervals, and the average value was calculated. In addition, for each raw film and each stretched film of the example, the average thickness was approximately the same as the thickness near the center of the film.

[0326] [raw material]

[0327] FDPM: 9,9-bis(2-methoxycarbonylethyl)fluorene [Alternative: dimethyl ester of 9,9-bis(2-carboxyethyl)fluorene, or dimethyl ester of fluorene-9,9-dipropionic acid], synthesized in the same manner as Example 1 described in Japanese Patent Publication No. 2005-89422, except that 56.6 g (0.44 mol) of t-butyl acrylate was changed to 37.9 g (0.44 mol) of methyl acrylate.

[0328] BPEF: 9,9-Bis[4-(2-hydroxyethoxy)phenyl]fluorene, manufactured by Osaka Gas Chemical Co., Ltd.

[0329] EG: Ethylene glycol

[0330] Polyamide resin: In formula (4), Y 1 This CH2 group, a diamine unit with r1 and r2 0, and a dicarboxylic acid unit derived from dodecane acid [-OC-(CH2) 10 Polyamide resin formed from ] -CO-, "Trogamide CX7323" manufactured by Daicel Evonik Corp., glass transition temperature Tg: 132 ℃

[0331] [Synthesized Example 1]

[0332] To FDPM 1.00 mol, BPEF 0.90 mol, and EG 2.10 mol, 2 × 10⁻⁶ manganese acetate tetrahydrate as an ester exchange catalyst -4 Moles and calcium acetate monohydrate 8 × 10 -4 Moles were added, and the mixture was slowly heated and melted while stirring. After raising the temperature to 230 °C, trimethylphosphate 14 × 10 -4 Moles, germanium oxide 20 × 10⁻⁶ -4 Molars were added, and EG was removed while gradually increasing the temperature and decreasing the pressure until it reached 270°C and 0.13 kPa or less. After reaching a predetermined stirring torque, the contents were removed from the reactor, and pellets of fluorene ring-containing polyester were prepared.

[0333] The obtained pellets, 1As a result of analysis by H-NMR, 100 mol% of the dicarboxylic acid units introduced into the fluorene ring-containing polyester were of FDPM, 90 mol% of the introduced diol units were of BPEF, and 10 mol% were of EG.

[0334] The glass transition temperature Tg of the obtained fluorene ring-containing polyester was 127 °C, and the weight average molecular weight Mw was 60,000.

[0335] [Examples 1 to 5]

[0336] A 2-type, 3-layer multilayer film was produced by using a fluorene ring-containing polyester produced in Synthesis Example 1 as the skin layer and a polyamide resin as the core layer, with skin layers laminated on both sides of the core layer. Specifically, after drying the fluorene ring-containing polyester and the polyamide resin, they were each fed into an extruder equipped with a feed block type T die (die width 300 mm) (extruder for skin layer: φ25 mm, L / D = 25; extruder for core layer: φ30 mm, L / D = 38), and melt extrusion molded to achieve the set film thickness (thickness of each layer, total thickness) of the base film listed in Table 1, thereby producing a 2-type, 3-layer multilayer film (base film) with an average total thickness of 100 μm.

[0337] The obtained multilayer film was cut to a size of 60 mm × 60 mm, and a stretched film was produced by using a tenter-type stretching device ("IMC-1 A97 type" manufactured by Imoto Seisakusho Co., Ltd.) to perform fixed-end uniaxial stretching in the TD direction on an area with an effective width of 40 mm excluding the chuck part at the stretching temperature and stretching ratio listed in Table 1 and a stretching speed of 120 mm / min (300% / min). In addition, the multilayer film was subjected to a preheating treatment for 10 minutes at the same temperature as the stretching temperature before stretching. Furthermore, the thickness ratio of each layer in the obtained stretched film was equivalent to the thickness ratio of each layer in the base film.

[0338] The Ro (450), Ro (550), Ro (450) / Ro (550) of the obtained stretched film and the average thickness (total film thickness) of the film after stretching are shown in Table 1.

[0339] In addition, in Table 1, the skin layer thickness of the original film represents the total film thickness of two layers, and the film thickness per skin layer is 37.5 μm.

[0340]

[0341] As can be seen from Table 1, the phase difference films obtained in Examples 1 to 5 have characteristics suitable for a broadband quarter-wave plate and are also prepared as thin films with a film thickness in the 30 μm range. In addition, the Tg of the fluorene ring-containing polyester and polyamide resins forming the phase difference films of Examples 1 to 5 is relatively high, and the heat resistance (environmental reliability) is also excellent. Among them, Examples 1 to 4 are preferred because they are close to the characteristics of an ideal broadband quarter-wave plate (Ro(550) is 137.5 nm, Ro(450) / Ro(550) is 0.818) and are also thin films, more preferably Examples 1, 2, and 4, and even more preferably Examples 2 and 4.

[0342] [Examples 6 to 8]

[0343] A multilayer film (base film) of two types and three layers was produced in the same manner as in Example 1, wherein the fluorene ring-containing polyester produced in Synthesis Example 1 was used as the skin layer and the polyamide resin as the core layer, and the skin layers were laminated on both sides of the core layer. The film was melt-extruded to achieve the set film thickness (thickness of each layer, total thickness) of the base film listed in Table 2, and the total thickness of the two types and three layers was set to an average of 170 μm.

[0344] The obtained multilayer film was cut to a size of 60 mm × 60 mm, and a stretched film was produced by sequentially biaxially stretching an area with an effective width of 40 mm (stretched in the MD direction, then stretched in the TD direction) using a tenter-type stretching device ("IMC-1A97 type" manufactured by Imoto Seisakusho Co., Ltd.) at the stretching temperature and stretching ratio listed in Table 2 and a stretching speed of 120 mm / min (300% / min) in each stretching direction. In addition, the multilayer film was subjected to a preheating treatment for 10 minutes at the same temperature as the stretching temperature before stretching. Furthermore, the thickness ratio of each layer in the obtained stretched film was equivalent to the thickness ratio of each layer in the base film. The Ro (450), Ro (550), Ro (450) / Ro (550), Rth (589) of the obtained stretched film and the average thickness (total film thickness) of the film after stretching are shown in Table 2.

[0345]

[0346] In addition, in Table 2, the skin layer thickness of the base film represents the total film thickness of two layers, and the film thickness per skin layer is 65 μm. Also, the stretching temperature is the same for stretching in the MD direction and the TD direction, and the stretching ratio means the ratio in the longitudinal direction (MD direction or film length direction) × the ratio in the transverse direction (TD direction or film width direction).

[0347] As can be seen from Table 2, the phase difference films obtained in Examples 6 to 8 have characteristics suitable for optical compensation films for VA-LCDs and are also prepared as thin films. In particular, Examples 6 and 7 are preferred in that Ro and Rth are in a more desirable range.

[0348] Industrial applicability

[0349] The phase difference film of the present disclosure has excellent phase difference expression and inverse wavelength dispersion. Therefore, it can be manufactured under mild stretching conditions, is thin, has excellent mechanical strength (or handling properties) such as toughness, and has excellent environmental reliability. Therefore, it can be preferably used in a circular polarizer having broadband anti-reflection performance, an organic EL display having said circular polarizer, a phase difference film for VA-LCD, and a vertically aligned liquid crystal display device.

Claims

Claim 1 A phase difference film comprising a polyester resin that exhibits negative orientation birefringence and also exhibits net wavelength dispersion of phase difference, and a polyamide resin that exhibits positive orientation birefringence and also exhibits flat dispersion of phase difference. Claim 2 A phase difference film according to claim 1, wherein the polyester resin comprises a constituent unit having a fluorene-9,9-diyl group, and the polyamide resin comprises a constituent unit having a cycloaliphatic backbone. Claim 3 In claim 1 or 2, the polyester resin comprises at least one constituent unit selected from a fluoredicarboxylic acid unit (A1) and a fluorediol unit (B1) as a constituent unit having a fluoren-9,9-diyl group, and the fluoredicarboxylic acid unit (A1) is of the following formula (1) (during food, R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b It includes a dicarboxylic acid unit represented by (which represents a divalent hydrocarbon group that may each have a substituent independently), and the fluorediol unit (B1) is, the following formula (2) (during food, R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b represents a divalent hydrocarbon group that may each independently have a substituent, and A 1a and A 1b A phase difference film comprising a diol unit represented by (where each independently represents a straight-chain or branched-chain alkylene group, and n1 and n2 represent integers greater than or equal to 0). Claim 4 In claim 3, the fluorediol unit (B1) is of the following formula (2A) (in food, Z 1a and Z 1b Each independently represents an Aren ring, and R 3a and R 3b ☐ each independently represents a substituent, p1 and p2 each independently represent an integer greater than or equal to 0, and R 2 , m, A 1a and A 1b A phase difference film comprising a diol unit represented by (2) described in claim 3, where n1 and n2 are each the same as the formula (2). Claim 5 In claim 4, the polyester resin is of the following formula (3) (during food, A 2 A phase difference film comprising a (poly)alkylene glycol unit (B2) represented by , where represents a straight-chain or branched-chain alkylene group and q represents an integer greater than or equal to 1. Claim 6 In claim 5, the polyester resin is, in formula (1), X 1a and X 1b a straight chain type or branched chain type C 2-4 It is an alkylene group, and in the above formula (2A), Z 1a and Z 1b Ga C 6-12 It is an Aren ring, and R 3a and R 3b Ga C 1-4 alkyl group or C 6-10 It is an aryl group, p1 and p2 are integers from 0 to 2, and A 1a and A 1b a straight chain type or branched chain type C 2-4 It is an alkylene group, where n1 and n2 are integers from 0 to 2, and in the above formula (3), A 2 a straight chain type or branched chain type C 2-4 A phase difference film having an alkylene group, where q is an integer from 1 to 4. Claim 7 In claim 1 or 2, the polyamide resin is of the following formula (4) (during food, Y 1 represents a divalent hydrocarbon group that may be directly bonded or have a substituent, and R 4a and R 4b A phase difference film comprising a diamine unit represented by , where each independently represents a substituent, and r1 and r2 each independently represent an integer from 0 to 4. Claim 8 In claim 7, the polyamide resin comprises a phase difference film having a constituent unit derived from an aliphatic dicarboxylic acid component. Claim 9 In claim 8, the polyamide resin is, in the formula (4), Y 1 This C 1-4 It is an alkylene group, and R 4a and R 4b Ga C 1-4 It is an alkyl group, a diamine unit in which r1 and r2 are 0 or 1, and a straight-chain or branched-chain C 4-16 Phase difference film comprising constituent units derived from alkane-dicarboxylic acid components. Claim 10 A phase difference film according to claim 1 or 2, wherein the difference between the glass transition temperature of the polyester-based resin and the glass transition temperature of the polyamide-based resin is 0 to 20 ℃. Claim 11 A phase difference film that is a laminated film comprising a first layer comprising the polyester-based resin and a second layer comprising the polyamide-based resin, in accordance with claim 1 or 2. Claim 12 In claim 11, a phase difference film having a three-layer structure in which the first layer is laminated on both sides of the second layer. Claim 13 A phase difference film according to claim 11, wherein the ratio of the total thickness of the first layer to the total thickness of the second layer is the former / the latter = 1 / 1 to 10 / 1. Claim 14 A phase difference film having a thickness of 20 to 70 μm, according to claim 1 or 2. Claim 15 A phase difference film that is a uniaxially stretched film according to claim 1 or 2. Claim 16 A phase difference film according to claim 15, wherein Ro(λ) is the in-plane phase difference at wavelength λ nm, Ro(550) is 100 to 160 nm, and Ro(450) / Ro(550) is 0.7 or more and less than 1. Claim 17 In claim 15, a phase difference film that is a quarter wavelength plate. Claim 18 A phase difference film that is a biaxially stretched film according to claim 1 or 2. Claim 19 A phase difference film according to claim 18, wherein Ro (λ) is the in-plane phase difference at wavelength λ nm and Rth (λ) is the thickness direction phase difference, Ro (550) is 30 to 50 nm, Ro (450) / Ro (550) is 0.7 or more and less than 1, and Rth (589) is 120 to 140 nm. Claim 20 In claim 18, a phase difference film which is an optical compensation film for a vertically aligned liquid crystal display. Claim 21 A polarizing plate comprising a phase difference film as described in claim 1 or 2. Claim 22 An image display device comprising a polarizing plate as described in claim 21. Claim 23 In claim 22, an image display device that is an organic EL display or a vertically aligned liquid crystal display.

Images