Phase difference film and its application

Abstract

A polyester resin showing negative orientation birefringence and phase difference showing wavelength dispersion is combined with a polyamide resin showing positive orientation birefringence and phase difference showing flat dispersion to form a phase difference film. The polyester resin may contain a constituent unit having a fluorene-9,9-diyl group, and the polyamide resin may contain a constituent unit having an alicyclic skeleton. The polyester resin may contain at least one constituent unit selected from a fluorene dicarboxylic acid unit (A1) containing a unit represented by the following formula (1) and a fluorene diol unit (B1) containing a unit represented by the following formula (2). (Wherein, R 1 , R 2 represents a substituent, k and m represent integers of 0 to 8, and X 1a , X 1b , X 2a , X 2b A represents a hydrocarbon group. 1a , A 1b represents an alkylene group, and n1 and n2 represent integers greater than 0). The retardation film has both high retardation performance and reverse wavelength dispersion.

Description

Technical Field

[0001] The present invention relates to a phase difference film and uses thereof. Background Art

[0002] In image display devices mounted on televisions, smartphones, and the like, various retardation films are used depending on the type and the like.

[0003] For example, in image display devices such as reflective liquid crystal display devices, semi-transmissive liquid crystal display devices, touch panel displays, and organic EL displays, in order to control the polarization state to display images or absorb reflected light to ensure visibility, a circular polarizer is used by laminating a quarter wave plate (quarter wave plate) and a polarizer (linear polarizer) in a manner that the absorption axis of the polarizer is at an angle of 45° relative to the slow axis of the quarter wave plate. In particular, organic EL displays are not only used in smartphones, but also gradually increase in televisions. Therefore, from the necessity of preventing external light reflection and improving visibility and contrast, the importance of circular polarizers with excellent wavelength dispersion over a wide band (broadband) increases. In detail, in an organic EL display, by utilizing a circular polarizer to absorb reflected light to suppress light leakage, blue coloring can be prevented to improve visibility, and insufficient black display accompanying the coloring can be prevented, so that the contrast can be improved. Therefore, if the circular polarizer does not have a retardation film (wideband quarter-wave plate) having reverse wavelength dispersion that shows a phase difference of approximately 1 / 4 wavelength in a wide band of visible light, reflected light of a specific wavelength may leak and visibility and contrast may be reduced.

[0004] Most general polymers show a forward wavelength dispersion in which the phase difference decreases with a longer wavelength, or a flat dispersion in which the phase difference does not change much. However, there are limited polymers that show a reverse wavelength dispersion in which the phase difference increases with a longer wavelength. As a polymer film showing such reverse wavelength dispersion, a polyester resin film such as a copolycarbonate or copolyester containing a structural unit having a cardo structure (i.e., a 9,9-diphenylfluorene skeleton) in which a main chain aromatic ring and a side chain aromatic ring are orthogonal and a structural unit having an isosorbide ring or a cyclohexane ring has been developed for use in circular polarizers (Patent Documents 1 to 3).

[0005] On the other hand, a phase difference film showing reverse wavelength dispersion is also required in large liquid crystal display devices (LCD), especially liquid crystal televisions. Among the two modes of vertical alignment mode (VA-LCD) and in-plane drive mode (IPS-LCD), the mainstream of liquid crystal televisions is VA-LCD with high front contrast and very wide viewing angles up, down, left and right. In the VA mode, since it is difficult to ensure a high contrast viewing angle in an oblique direction, a phase difference film is arranged between the liquid crystal unit and each polarizer arranged above and below it to ensure the above-mentioned oblique viewing angle.

[0006] In the retardation film for VA-LCD, reverse wavelength dispersion is very important from the viewpoint of compensating the phase difference in the entire visible light region (or compensating the viewing angle), and it is said to be particularly effective in suppressing the color shift that changes the color tone with the change of the viewing angle. As the material of such a retardation film for VA-LCD, cellulose acetate propionate (CAP) is used, which can be given reverse wavelength dispersion by additives.

[0007] However, in recent years, the open-box method of transporting LCD panels to TV manufacturers in simple packaging has increased, resulting in poor image display performance due to moisture absorption of CAP during transportation. Therefore, cyclic olefin copolymers (COP) are increasingly being used instead of CAP with high water absorption, but COP has a flat dispersion and cannot effectively suppress color shift.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2010-134232

[0011] Patent Document 2: Japanese Patent Application Publication No. 2012-31369

[0012] Patent Document 3: Japanese Patent Application Publication No. 2018-151627 Summary of the invention

[0013] Problems to be solved by the invention

[0014] In recent years, in order to make displays thinner or lighter, the phase difference film is also required to be thinner, but the phase difference is proportional to the thickness of the film. Therefore, in order to make the film thinner while maintaining the desired phase difference, the birefringence needs to be adjusted to be higher. Although the films showing reverse wavelength dispersion described in patent documents 1 to 3 show phase difference by uniaxial stretching, their inherent birefringence (or phase difference expression) is small. Therefore, in order to form a film, it is difficult to obtain the desired phase difference if the stretching conditions are not strictly enforced and the oriented birefringence is not increased. However, these polymers are mainly formed by a rigid structure containing a cardo structure and a ring structure such as an isosorbide ring or a cyclohexane ring. Therefore, the film is brittle and easily broken by stretching, and the strict stretching conditions are limited. In particular, it is extremely difficult to form a phase difference film for VA-LCD that adjusts the phase difference by biaxial stretching with stretching conditions stricter than uniaxial stretching.

[0015] In addition, even if it can be formed into a thin film by stretching, it is brittle and therefore has the following risks: insufficient mechanical strength makes it difficult to handle, and under strict stretching conditions, the film shrinks due to residual stress, and environmental reliability (heat resistance and water resistance (humidity resistance) and dimensional stability and phase difference stability to heat and moisture) are reduced. Therefore, it is impossible to simply or effectively manufacture a thin and high-quality phase difference film.

[0016] Furthermore, generally speaking, there is a tendency for a trade-off between high phase difference and reverse wavelength dispersibility. That is, although the phase difference of a film with reverse wavelength dispersibility increases with the strictness of the stretching conditions, the wavelength dispersion characteristics easily change from reverse dispersion to forward dispersion (or forward dispersion). Therefore, it is not easy to simultaneously satisfy the desired phase difference and reverse wavelength dispersibility by stretching conditions. In particular, films with reverse wavelength dispersibility usually have low phase difference performance as described above, so it is more difficult to take into account both phase difference and reverse wavelength dispersibility.

[0017] Therefore, an object of the present disclosure is to provide a novel retardation film having both high retardation expression and reverse wavelength dispersion (reverse wavelength dispersion of in-plane retardation Ro), and use thereof.

[0018] Means of solving problems

[0019] The present inventors have conducted intensive studies to achieve the above-mentioned problems and have found that when a polyester resin having negative orientation birefringence and forward wavelength dispersion as a single film is combined with a polyamide resin having positive orientation birefringence and flat dispersion as a single film to form a retardation film, high retardation expression and reverse wavelength dispersion are exhibited, thereby completing the present invention.

[0020] That is, the retardation film of the present disclosure includes:

[0021] A polyester resin showing negative orientation birefringence and phase difference dispersibility along the wavelength, and

[0022] A polyamide-based resin that exhibits positive orientation birefringence and flat phase difference dispersion.

[0023] The polyester resin includes a constituent unit having a fluorene-9,9-diyl group, and the polyamide resin may include a constituent unit having an alicyclic skeleton. The polyester resin includes 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, the fluorene dicarboxylic acid unit (A1) includes 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).

[0024] [Chemistry 1]

[0025]

[0026] (Where R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b Each independently represents a divalent hydrocarbon group which may have a substituent).

[0027] [Chemistry 2]

[0028]

[0029] (Where R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b Each independently represents a divalent hydrocarbon group which may have a substituent, A 1a and A 1b Each independently represents a linear or branched alkylene group, and n1 and n2 represent an integer greater than 0.

[0030] The fluorene diol unit (B1) may include a diol unit represented by the following formula (2A).

[0031] [Chemistry 3]

[0032]

[0033] (Where Z 1a and Z 1b Each independently represents an aromatic hydrocarbon ring, R 3a and R 3b Each independently represents a substituent, p1 and p2 each independently represent an integer greater than 0, R 2 ,m,A 1a and A 1b , n1 and n2 are respectively the same as those defined in the above formula (2).

[0034] The polyester resin may contain a (poly)alkylene glycol unit (B2) represented by the following formula (3).

[0035] [Chemistry 4]

[0036]

[0037] (In the formula, A 2 represents a linear or branched alkylene group, and q represents an integer greater than 1).

[0038] Regarding the polyester resin, in the above formula (1), X 1a and X 1b Straight or branched chain C 2-4 Alkylene,

[0039] In the above formula (2A), Z 1a and Z 1b C 6-12 Aromatic ring, R 3a and R 3b C 1-4 Alkyl or C 6-10 Aryl, p1 and p2 are integers from 0 to 2, A 1a and A 1b Straight or branched chain C 2-4 Alkylene, n1 and n2 are integers from 0 to 2,

[0040] In the above formula (3), A 2 Straight or branched chain C 2-4 The alkylene group, q may be an integer of 1 to 4.

[0041] The polyamide resin may contain a diamine unit represented by the following formula (4).

[0042] [Chemistry 5]

[0043]

[0044] (In the formula, Y 1 represents a direct bond or a divalent hydrocarbon group which may have a substituent, R 4a and R 4b Each independently represents a substituent, and r1 and r2 each independently represent an integer of 0 to 4).

[0045] The polyamide resin may contain a structural unit (dicarboxylic acid unit) derived from an aliphatic dicarboxylic acid component. 1 C 1-4 Alkylene, R 4a and R 4b C 1-4 Alkyl, r1 and r2 are 0 or 1 diamine units and linear or branched C 4-16 The structural unit of the alkane-dicarboxylic acid component (dicarboxylic acid unit).

[0046] In the above-mentioned phase difference film, the difference between the glass transition temperature of the polyester resin and the glass transition temperature of the polyamide resin can be about 0 to 20°C. The phase difference film can be a laminated film including a first layer containing a polyester resin and a second layer containing a polyamide resin. The above-mentioned phase difference film can be a laminated film with a three-layer structure in which the second layer is laminated on both sides of the above-mentioned first layer, and preferably a laminated film with a three-layer structure in which the first layer is laminated on both sides of the above-mentioned second layer. In the above-mentioned phase difference film, the ratio of the total thickness of the above-mentioned first layer to the total thickness of the above-mentioned second layer can be the former / the latter = about 1 / 1 to 10 / 1. The thickness of the above-mentioned phase difference film can be about 20 to 70 μm.

[0047] The above-mentioned retardation film may be a uniaxially stretched film. The above-mentioned retardation film is a uniaxially stretched film that is stretched obliquely relative to the length direction of the film, and the angle between the slow axis in the film plane and the length direction of the film may be about 40 to 50°. When the in-plane retardation of the above-mentioned retardation film at a wavelength of λnm is set to Ro(λ), Ro(550) is about 100 to 160nm, and Ro(450) / Ro(550) may be about 0.7 or more and less than 1. The above-mentioned retardation film may be a quarter wave plate.

[0048] In addition, the above-mentioned phase difference film can be a biaxially stretched film. The slow axis in the film plane of the above-mentioned phase difference film is approximately perpendicular to the length direction of the film, for example, it can be about 85 to 95°. When the in-plane phase difference at a wavelength λnm of the above-mentioned phase difference film is set to Ro(λ) and the phase difference in the thickness direction is set to Rth(λ), Ro(550) is about 30 to 50nm, Ro(450) / Ro(550) is about 0.7 or more and less than 1, and Rth(589) can be about 120 to 140nm. The above-mentioned phase difference film can be an optical compensation film for a liquid crystal display in a vertical alignment mode.

[0049] The present disclosure also includes a polarizer including the phase difference film, and an image display device including the polarizer. The image display device may be an organic EL display or a vertical alignment mode liquid crystal display.

[0050] It should be noted that in the present specification and claims, "positive" for orientation birefringence (or orientation birefringence) and intrinsic birefringence refers to the property that, within the plane of a polymer oriented film (or uniaxially stretched film), the refractive index in the orientation direction (or stretching direction) shows a value greater than the refractive index in the direction perpendicular to the orientation direction, and "negative" refers to the property that the refractive index in the orientation direction is less than the refractive index in the direction perpendicular to the orientation direction.

[0051] In addition, regarding wavelength dispersion, "forward wavelength dispersion" or "forward dispersion (or positive dispersion)" in this specification and claims refers to the property that the absolute value of the in-plane phase difference Ro decreases as the wavelength becomes longer, especially Ro(450) / Ro(550) at a measurement temperature of 20°C is greater than 1.05; "reverse wavelength dispersion" or "reverse dispersion" refers to the property that the absolute value of the in-plane phase difference Ro increases as the wavelength becomes longer, especially Ro(450) / Ro(550) at a measurement temperature of 20°C is less than 1; "flat dispersion (or flat dispersion)" refers to the property that the absolute value of the in-plane phase difference Ro hardly changes with the wavelength, especially Ro(450) / Ro(550) at a measurement temperature of 20°C is 1 to 1.05.

[0052] In the present specification and claims, a "diol unit" or a "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 a "diol component" (including compounds exemplified as diol components) is sometimes used synonymously with a corresponding "diol unit".

[0053] Similarly, a "dicarboxylic acid unit" or a "constituent unit derived from a dicarboxylic acid component" refers to a unit (or a divalent group) obtained by removing two OH (hydroxyl) groups from two carboxyl groups of a corresponding dicarboxylic acid, and a "dicarboxylic acid component" (including the compounds exemplified as the dicarboxylic acid component) is sometimes used synonymously with the corresponding "dicarboxylic acid unit".

[0054] It should be noted that in the present specification and claims, "dicarboxylic acid component" means, in addition to dicarboxylic acids, ester-forming derivatives thereof, such as dicarboxylic acid lower alkyl esters, dicarboxylic acid halides, dicarboxylic acid anhydrides, etc. Examples of the dicarboxylic acid lower alkyl esters include methyl esters, ethyl esters, tert-butyl esters, etc. 1-4 Alkyl esters, etc. Examples of the dicarboxylic acid halide include dicarboxylic acid chlorides and dicarboxylic acid bromides. In addition, the "ester-forming derivative" may be a monoester (half ester) or a diester.

[0055] In addition, a "diamine unit" or a "constituent unit derived from a diamine component" refers to a unit (or a divalent group) obtained by removing one hydrogen atom from each of two amino groups of a corresponding diamine, and a "diamine component" (including the compounds exemplified as the diamine component) is sometimes used synonymously with the corresponding "diamine unit".

[0056] In the present specification and claims, the number of carbon atoms in a substituent may be expressed as C1, C6, C 10 For example, an alkyl group with 1 carbon number is represented by "C1 alkyl", and an aryl group with 6 to 10 carbon numbers is represented by "C 6-10 Aryl" means.

[0057] Effects of the Invention

[0058] The phase difference film disclosed in the present invention is formed by combining a polyester resin showing negative orientation birefringence and phase difference showing forward wavelength dispersion and a polyamide resin showing positive orientation birefringence and phase difference showing flat dispersion, so that high phase difference expression and excellent (or appropriate) reverse wavelength dispersion can be taken into account. Therefore, even if it is formed into a thin film, it is easy to maintain the desired phase difference, and a phase difference film with excellent balance of thinness, phase difference and reverse wavelength dispersion can be formed. In addition, even under relatively mild stretching conditions, it is easy to show phase difference, so the formability (or productivity) and environmental resistance reliability are high. In particular, when a polyester resin containing a constituent unit having a fluorene-9,9-diyl is combined with a polyamide resin containing a constituent unit having an alicyclic skeleton, a film having excellent toughness (or softness) can be prepared, so that the formability and handling properties can be further improved. Therefore, a broadband 1 / 4 wave plate and a VA-LCD phase difference film that can suppress color shift can be easily or effectively formed. DETAILED DESCRIPTION

[0059] In the present disclosure, a phase difference film is formed by combining a predetermined polyester-based resin and a predetermined polyamide-based resin.

[0060] [Polyester resin]

[0061] The polyester resin can be any resin that shows negative oriented birefringence and phase difference along the wavelength dispersion in its single film (uniaxially stretched film). From the viewpoint of easy modulation of a phase difference film with excellent inverse wavelength dispersion, the along-wavelength dispersion of the polyester resin, especially the along-wavelength dispersion with a large change in the phase difference relative to the wavelength (steep along-wavelength dispersion), for example, the 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. As polyester resins, polyester resins, polycarbonate resins, polyester carbonate resins, etc. can be cited. These polyester resins can contain two or more alone or in combination. Among these polyester resins, polyester resins are preferred from the viewpoints of moldability and phase difference expression.

[0062] Examples of polyester resins exhibiting the above-mentioned properties include polyester resins containing structural units having fluorene-9,9-diyl (or fluorene-ene) groups, 9-fluorene groups, and the like. Preferably, polyester resins containing structural units having fluorene-9,9-diyl groups (resins in which the 9-position of the fluorene ring is located on the main chain and which have fluorene rings as side chains) and the like are mentioned.

[0063] The polyester resin preferably contains a dicarboxylic acid component (A) and a diol component (B) as polymer components. The structural unit having a fluorene ring-containing group may be a unit derived from any polymer component. It is preferred that the dicarboxylic acid unit (A) contains at least a dicarboxylic acid unit having a fluorene ring-containing group (hereinafter, also referred to as a fluorene dicarboxylic acid unit) (A1). It is particularly preferred that both the dicarboxylic acid unit (A) and the diol unit (B) have a structural unit containing a fluorene ring group.

[0064] (Dicarboxylic acid unit (A))

[0065] Fluorene dicarboxylic acid unit (A1)

[0066] As the fluorene dicarboxylic acid unit (A1), there can be mentioned a dicarboxylic acid unit represented by the following formula (1).

[0067] [Chemistry 6]

[0068]

[0069] (Where R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b Each independently represents a divalent hydrocarbon group which may have a substituent).

[0070] In the above formula (1), as X 1a and X 1b The divalent hydrocarbon group in the above-mentioned group may be a divalent aromatic hydrocarbon group such as phenylene, preferably a divalent alicyclic hydrocarbon group such as cyclohexylene, a divalent aliphatic hydrocarbon group, and particularly preferably a divalent aliphatic hydrocarbon group. 1a and X 1b When X is a divalent alicyclic or aliphatic hydrocarbon group, the wavelength dependence of the refractive index in the main chain direction becomes smaller and the wavelength dependence of the refractive index in the direction orthogonal to the main chain direction becomes larger by combining with the fluorene ring structure (fluorene-9,9-diyl) of the side chain. Therefore, it is easy to prepare a polyester resin with negative orientation birefringence, forward wavelength dispersion, and large wavelength dependence. In particular, when X 1a and X 1b When it is a divalent aliphatic hydrocarbon group, the phase difference expression becomes higher, and it can be stretched under more stable stretching conditions. Furthermore, the toughness (softness) of the polyester resin can be improved, thereby forming a film that is not easy to break and has excellent formability and operability (handling properties), or reducing thermal shrinkage caused by residual stress, etc., so it is preferred from the viewpoint of forming a thinner phase difference film.

[0071] As X 1a and X 1bThe divalent aliphatic hydrocarbon group represented by may be a straight-chain or branched alkenylene group, a straight-chain or branched alkynylene group, etc., but is preferably a straight-chain or branched alkylene group. Examples of the straight-chain or branched alkylene group include a straight-chain or branched C alkylene group such as methylene, ethylene, trimethylene, propylene, 1,2-butanediyl, 2-methylpropane-1,3-diyl, etc. 1-8 Among them, linear or branched C 1-6 Alkylene, more preferably linear or branched C 1-4 Alkylene, more preferably linear or branched C 2-4 Alkylene, among which linear or branched C 2-3 Alkylene is particularly preferably ethylene. 1a and X 1b They may be different from each other, but are preferably the same group.

[0072] In addition, as X 1a and X 1b The substituents that the divalent hydrocarbon group represented by may have include aryl groups such as phenyl and cycloalkyl groups such as cyclohexyl. The number of substituents is not particularly limited, and is, for example, 0 to 10, preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0. Examples of the divalent hydrocarbon group having a substituent include 1-phenylethylene, 1-phenylpropane-1,2-diyl, and the like. 1a and X 1b It is preferably a linear or branched alkylene group having no substituent.

[0073] In the above formula (1), the group R 1 , may be a non-polymerizable group or a non-reactive substituent group inert to the polymerization reaction, for example, a cyano group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom; a hydrocarbon group such as an alkyl group and an aryl group; etc. As the above-mentioned aryl group, there may be mentioned: a C 6-10 Aryl etc. As the preferred group R 1 , is a cyano group, a halogen atom or an alkyl group, in particular is an alkyl group.

[0074] Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl and the like. 1-12 Alkyl, preferably C 1-8 Alkyl groups, particularly preferably methyl groups, etc. 1-4 Alkyl, etc.

[0075] It should be noted that when the group R 1 When the number of substitutions k is plural (2 or more), in the two benzene rings constituting the fluorene ring, the two or more groups R substituted on the same benzene ring 1The types may be the same or different, and the two or more groups R substituted on different benzene rings 1 The types of R can be the same or different. 1 The bonding position (substitution position) of is not particularly limited, and examples thereof include the 2-position, 7-position, and 2,7-position of the fluorene ring.

[0076] The number of substitutions k may be, for example, an integer of about 0 to 6, preferably 0 to 4, 0 to 3, or 0 to 2, preferably 0 or 1, and particularly preferably 0. 1 The respective substitution numbers may be different from each other, but are preferably the same.

[0077] Typical examples of the dicarboxylic acid unit represented by the above formula (1) include: 1a and X 1b Straight or branched chain C 2-6 The constituent unit of the alkylene group includes, for example, units derived from 9,9-bis(2-carboxyethyl)fluorene, 9,9-bis(2-carboxypropyl)fluorene and the like. 2-6 The dicarboxylic acid units represented by the above formula (1) can be used alone or in combination of two or more. Among the dicarboxylic acid units represented by the above formula (1), 9,9-bis(carboxyl C 2-6 9,9-bis(carboxyl C 2-4 9,9-bis(2-carboxyethyl)fluorene, 9,9-bis(2-carboxypropyl)fluorene, etc. 2-3 The constituent unit of the fluorene is alkyl) fluorene.

[0078] The fluorene dicarboxylic acid unit (A1) can be used alone or in combination of two or more. The ratio of the dicarboxylic acid unit represented by the above formula (1) to the total fluorene dicarboxylic acid unit (A1) can be, for example, 1 mol% or more, specifically, it can be selected from the range of about 10 to 100 mol%, and as a preferred range, the following are preferably 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 preferably 100 mol%, and the fluorene dicarboxylic acid unit (A1) basically contains only the dicarboxylic acid unit represented by the above formula (1). When the ratio of the dicarboxylic acid unit represented by the above formula (1) is too small, it may not be possible to form a polyester resin showing negative orientation birefringence and wavelength dispersion.

[0079] In the dicarboxylic acid unit represented by the above formula (1), X 1a and X 1b is a linear or branched alkylene group, especially a linear or branched C 2-6The proportion of the constituent units of the alkylene group may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, and preferably, 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, in that order, and 100 mol% is particularly preferred. The dicarboxylic acid units represented by the above formula (1) contain substantially only X 1a and X 1b is a linear or branched alkylene group, especially a linear or branched C 2-6 The constituent unit of the alkylene group. 1a and X 1b is a linear or branched alkylene group, especially a linear or branched C 2-6 When the ratio of the structural unit of the alkylene group is too small, the polyester-based resin that exhibits negative orientation birefringence and down-wavelength dispersion may not be formed, and it may be difficult to form a thinner retardation film.

[0080] Second dicarboxylic acid unit (A2)

[0081] The polyester resin may not contain a dicarboxylic acid unit (second dicarboxylic acid unit (A2)) different from the fluorene dicarboxylic acid unit (or first dicarboxylic acid unit) (A1) as the dicarboxylic acid unit (A), but may contain it as necessary within a range not impairing the effects of the present disclosure.

[0082] Examples of the second dicarboxylic acid unit (A2) include structural units derived from an aromatic dicarboxylic acid component [excluding the fluorene dicarboxylic acid component (A1)], an alicyclic dicarboxylic acid component, an aliphatic dicarboxylic acid component, and the like.

[0083] Examples of the aromatic dicarboxylic acid component include benzene dicarboxylic acid, alkylbenzene dicarboxylic acid, polycyclic aromatic dicarboxylic acid, diaryl alkane dicarboxylic acid, diaryl ketone dicarboxylic acid, and ester-forming derivatives thereof.

[0084] As a benzene dicarboxylic acid, a phthalic acid, an isophthalic acid, a terephthalic acid etc. are mentioned, for example.

[0085] Examples of the alkylbenzenedicarboxylic acid include 4-methylisophthalic acid, 5-methylisophthalic acid, and the like. 1-4 Alkyl-benzenedicarboxylic acids, etc.

[0086] As a polycyclic aromatic dicarboxylic acid, a condensed polycyclic aromatic dicarboxylic acid, a ring-aggregated aromatic dicarboxylic acid, etc. are mentioned, for example.

[0087] Examples of the condensed polycyclic aromatic dicarboxylic acid include naphthalene dicarboxylic acids such as 1,2-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, and 2,6-naphthalene dicarboxylic acid; anthracene dicarboxylic acid; and condensed polycyclic C 10-24 Aromatic hydrocarbon-dicarboxylic acid, preferably: condensed polycyclic C 10-14 Aromatic hydrocarbons - dicarboxylic acids, etc.

[0088] Examples of the ring-aggregated aromatic dicarboxylic acid include biphenyl dicarboxylic acid such as 2,2'-biphenyl dicarboxylic acid, 3,3'-biphenyl dicarboxylic acid, and 4,4'-biphenyl dicarboxylic acid. 6-10 Aromatic hydrocarbons - dicarboxylic acids, etc.

[0089] Examples of the diarylalkane dicarboxylic acid include di-C arylalkane dicarboxylic acids such as 4,4'-diphenylmethane dicarboxylic acid and the like. 6-10 Aryl C 1-6 Alkanes-dicarboxylic acids, etc.

[0090] Examples of the diaryl ketone dicarboxylic acid include di(C) 6-10 Aryl) ketone-dicarboxylic acid, etc.

[0091] Examples of the alicyclic dicarboxylic acid component include cycloalkane dicarboxylic acids, crosslinked cyclic cycloalkane dicarboxylic acids, cycloolefin dicarboxylic acids, crosslinked cyclic cycloolefin dicarboxylic acids, and ester-forming derivatives thereof.

[0092] Examples of the cycloalkane dicarboxylic acid include 1,4-cyclohexane dicarboxylic acid and the like. 5-10 Cycloalkane-dicarboxylic acids, etc.

[0093] Examples of the cross-linked cyclic cycloalkane dicarboxylic acid include di- or tri-cyclodecane dicarboxylic acids such as decahydronaphthalene dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, and tricyclodecane dicarboxylic acid.

[0094] Examples of the cycloolefin dicarboxylic acid include cyclohexene dicarboxylic acid and the like. 5-10 Cycloolefin-dicarboxylic acids, etc.

[0095] Examples of the cross-linked cyclic cycloolefin dicarboxylic acid include di- or tri-cyclic olefin dicarboxylic acids such as norbornene dicarboxylic acid.

[0096] Examples of the aliphatic dicarboxylic acid component include alkane dicarboxylic acids, unsaturated aliphatic dicarboxylic acids, and ester-forming derivatives thereof.

[0097] Examples of the alkane dicarboxylic acid include succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, and the like. 2-12 Alkanes-dicarboxylic acids, etc.

[0098] Examples of the unsaturated aliphatic dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, and the like. 2-10 Olefin-dicarboxylic acids, etc.

[0099] These second dicarboxylic acid units (A2) can be used alone or in combination of two or more.

[0100] The ratio of the fluorene dicarboxylic acid unit (A1) to the whole dicarboxylic acid unit (A) may be, for example, 1 mol% or more, specifically, it may be selected from the range of about 10 to 100 mol%, and as preferred ranges, 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 are preferred in that order, and 100 mol% is particularly preferred, and the second dicarboxylic acid unit (A2) is substantially not contained. When the ratio of the fluorene dicarboxylic acid unit (A1) is too small, a polyester resin showing negative orientation birefringence and wavelength dispersibility may not be formed.

[0101] (Diol unit (B))

[0102] In the polyester-based resin, the diol unit (B) preferably contains a diol unit having a fluorene ring-containing group (hereinafter, also referred to as a fluorene diol unit) (B1).

[0103] Fluorene glycol unit (B1)

[0104] Examples of the fluorene diol unit (B1) include a diol unit represented by the following formula (2).

[0105] [Chemistry 7]

[0106]

[0107] (Where R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b Each independently represents a divalent hydrocarbon group which may have a substituent, A 1a and A 1b Each independently represents a linear or branched alkylene group, and n1 and n2 represent an integer greater than 0).

[0108] In the above formula (2), R 2 The substituent represented by and the number of substitutions m thereof, including preferred embodiments such as specific groups, ranges of the number of substitutions, and substitution positions, are respectively the same as R in the above formula (1). 1 The substituent represented by is the same as the number of substitution k.

[0109] In X 2a and X 2b In the formula (1), as a divalent hydrocarbon group, X 1aand X 1b Similarly, there can be mentioned divalent aliphatic hydrocarbon groups such as linear or branched alkylene groups, divalent alicyclic hydrocarbon groups such as cyclohexylene groups, divalent aromatic hydrocarbon groups such as phenylene groups, etc. Preferred divalent hydrocarbon groups are divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups.

[0110] In X 2a and X 2b The substituent that the divalent hydrocarbon group may have may be a non-reactive group or a non-polymerizable substituent that is inert to the polymerization reaction, and examples thereof include a halogen atom, a hydrocarbon group (or a group [-R h ]), group [-OR h ](where R h represents the above hydrocarbon group), group [-SR h ](where R h represents the above-mentioned hydrocarbon group), acyl group, nitro group, cyano group, mono- or di-substituted amino group, etc.

[0111] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0112] As the above R h Examples of the hydrocarbon group represented by include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group.

[0113] Examples of the alkyl group include linear or branched C alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. 1-10 Alkyl, preferably a linear or branched C 1-6 Alkyl, more preferably a linear or branched C 1-4 alkyl.

[0114] Examples of the cycloalkyl group include C groups such as cyclopentyl and cyclohexyl. 5-10 Cycloalkyl.

[0115] Examples of the aryl group include C phenyl, alkylphenyl, biphenyl, naphthyl and the like. 6-12 Examples of the alkylphenyl group include mono- to tri-C phenyl groups such as methylphenyl (or tolyl) and dimethylphenyl (or xylyl). 1-4 Alkyl-phenyl.

[0116] Examples of the aralkyl group include C 6-10 Aryl-C 1-4 alkyl.

[0117] As the above group [-OR h ], for example, alkoxy, cycloalkoxy, aryloxy, aralkyloxy, etc., specifically, the hydrocarbon group R hExamples of the alkoxy group include linear or branched C groups such as methoxy, ethoxy, propoxy, n-butoxy, isobutoxy, and tert-butoxy. 1-10 Examples of the cycloalkoxy group include cyclohexyloxy and the like. 5-10 Examples of the aryloxy group include C 6-10 Examples of the aralkyloxy group include C 6-10 Aryl-C 1-4 Alkoxy.

[0118] As the above group [-SR h ], for example, alkylthio, cycloalkylthio, arylthio, aralkylthio, etc., specifically, the hydrocarbon group R h Examples of the alkylthio group include methylthio, ethylthio, propylthio, n-butylthio, tert-butylthio, and the like. 1-10 Examples of the cycloalkylthio group include cyclohexylthio and the like. 5-10 Examples of the arylthio group include C thiophenoxy and the like. 6-10 Examples of the aralkylthio group include C 6-10 Aryl-C 1-4 Alkylthio.

[0119] Examples of the acyl group include C 1-6 Alkyl-carbonyl, etc.

[0120] Examples of the mono- or di-substituted amino group include dialkylamino groups and bis(alkylcarbonyl)amino groups. Examples of the dialkylamino group include di-C 2-(dimethylamino)- and di-C 2-(dimethylamino)- and di-C 2-(dimethylamino)- 1-4 Examples of the bis(alkylcarbonyl)amino group include bis(C)-(diacetylamino) and the like. 1-4 alkyl-carbonyl)amino.

[0121] In X 2a and X 2b In the above, the number of substituents which the divalent hydrocarbon group may have can be selected from the range of, for example, about 0 to 10, preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0.

[0122] X 2a and X 2b The types may be different from each other, but are preferably the same.

[0123] As alkylene A 1a and A 1b Examples include linear or branched C groups such as ethylene, propylene (1,2-propanediyl), trimethylene, 1,2-butanediyl, and tetramethylene.2-6 When the number of repetitions n1 or n2 is 1 or more, it is preferably a linear or branched C 2-4 Alkylene, more preferably a linear or branched C 2-3 The alkylene group is particularly preferably an ethylene group.

[0124] Oxyalkylene (-OA 1a -) and (-OA 1b -) repetition number (addition mole number) n1 and n2 can be 0 or more, for example, can be selected from the range of integers of about 0 to 15, and the preferred ranges are 0 to 10, 0 to 8, 0 to 6, 0 to 4, 0 to 2, and 0 to 1. In addition, when X 2a and X 2b When X is a divalent aliphatic hydrocarbon group such as a linear or branched alkylene group, the number of repetitions n1 or n2 is preferably 0. 2a and X 2b When it is a divalent aromatic hydrocarbon group, the repetition numbers n1 and n2 are preferably 1 or more from the viewpoint of improving polymerization reactivity, and can be selected from the range of integers of about 1 to 15, for example, and the preferred ranges are 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, 1 to 2, and 1 is particularly preferred. It should be noted that in this specification and claims, "repetition number (addition mole number)" may be an average value (arithmetic mean, arithmetic mean) or an average addition mole number, and the preferred mode is the same as the above-mentioned preferred range (the above-mentioned integer range). When the repetition number n1 and / or n2 is too large, the refractive index and heat resistance may decrease.

[0125] In addition, the two repeating numbers n1 and n2 may be the same or different from each other. When n1 or n2 is 2 or more, the two or more oxyalkylene groups (-OA 1a -) or (-OA 1b -) may be the same or different. 2a and X 2b Bonded (poly)oxyalkylene (-OA 1a -) n1 and (-OA 1b -) n2 The types may be the same or different from each other.

[0126] Typical examples of the diol unit represented by the above formula (2) include: 2a and X 2bA diol unit of a linear or branched alkylene group (hereinafter, also referred to as a dialkylfluorene diol unit) (B1-1), a diol unit represented by the formula (2A) described later (hereinafter, also referred to as a diarylfluorene diol unit) (B1-2), etc. These fluorene diol units (B1) can be used alone or in combination of two or more.

[0127] Dialkylfluorene diol unit (B1-1)

[0128] The dialkylfluorene diol unit (B1-1) is X 2a and X 2b It is a straight or branched alkylene group of an aliphatic hydrocarbon group. Therefore, as in the case of the fluorene dicarboxylic acid unit represented by the above formula (1), by combining with the fluorene ring structure (fluorene-9,9-diyl) of the side chain, the wavelength dependence of the refractive index in the main chain direction becomes smaller, and the wavelength dependence of the refractive index in the direction orthogonal to the main chain direction becomes larger, so it is easy to prepare a polyester resin with negative oriented birefringence, forward dispersion and large wavelength dependence. In addition, the phase difference expression is also high, not only can it be stretched under more stable stretching conditions, but also the toughness (flexibility) can be improved to form a film that is not easy to break and has excellent formability and operability, or the heat shrinkage caused by residual stress can be reduced, so it is preferred from the perspective of forming a thinner phase difference film.

[0129] In the dialkylfluorene diol unit (B1-1), the linear or branched alkylene group X 2a and X 2b Examples include straight-chain or branched C groups such as methylene, ethylene, trimethylene, propylene, 1,2-butanediyl, and 2-methylpropane-1,3-diyl. 1-8 Among them, linear or branched C 1-6 Alkylene, more preferably linear or branched C 1-4 Alkylene, more preferably linear or branched C 1-3 Alkylene, among which methylene, ethylene and the like are preferred 1-2 The alkylene group is particularly preferably a methylene group. Among these alkylene groups, when n1 and / or n2 is 0, a linear alkylene group is preferred from the viewpoint of being able to suppress a decrease in polymerization reactivity due to secondary alcohol.

[0130] Representative examples of the dialkylfluorene diol unit (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, and 9,9-bis(hydroxy linear or branched C 1-6 Alkyl)fluorene, etc.

[0131] These bis-alkylfluorene diol units (B1-1) can be used alone or in combination of two or more. Preferred bis-alkylfluorene diol units (B1-1) are 9,9-bis(hydroxy linear C 1-6 Alkyl) fluorene, more preferably 9,9-bis (hydroxy straight chain C 1-4 Alkyl) fluorene, more preferably 9,9-bis(hydroxy linear C 1-3 Alkyl) fluorene, among which 9,9-bis(hydroxy linear C 1-2 Preferably, it is 9,9-bis(hydroxymethyl)fluorene.

[0132] Bisarylfluorene diol unit (B1-2)

[0133] The bisarylfluorene diol unit (B1-2) represented by the following formula (2A) has the effect of making the orientation birefringence of the polyester resin negative, forward-dispersed, and increasing the wavelength dependence (making it steep forward wavelength dispersion) due to its cardo structure. 2a and X 2b The unit corresponding to the divalent aromatic hydrocarbon group has a large refractive index in the main chain direction and its wavelength dependence. Compared with the dialkylfluorene diol unit (B1-1), although the effect of adjusting the above optical properties (phase difference expression and wavelength dispersion characteristics) and the moldability and handleability from the film toughness may be slightly reduced, it is easy to increase the glass transition temperature of the polyester resin, so that the thermal shrinkage caused by the residual stress can be reduced, and the environmental resistance reliability (heat resistance and water resistance (humidity resistance) and dimensional stability and phase difference stability to heat and moisture) can be effectively improved, so it is preferred over the dialkylfluorene diol unit (B1-1). That is, the diarylfluorene diol unit (B1-2) is effective in adjusting the balance between the phase difference expression and wavelength dispersion characteristics and the environmental resistance reliability. Therefore, the bisarylfluorenediol unit (B1-2) is preferably combined with the fluorene dicarboxylic acid unit represented by the above formula (1) and / or the bialkylfluorenediol unit (B1-1), and more preferably combined with at least the fluorene dicarboxylic acid unit represented by the above formula (1).

[0134] [Chemistry 8]

[0135]

[0136] (Where Z 1a and Z 1b Each independently represents an aromatic hydrocarbon ring, R 3a and R 3b Each independently represents a substituent, p1 and p2 each independently represent an integer greater than 0, R 2 ,m,A 1a and A 1b, n1 and n2 (including preferred embodiments) are respectively the same as those defined in the above formula (2).

[0137] In the above formula (2A), Z 1a and Z 1b The aromatic hydrocarbon ring represented by , for example, includes monocyclic aromatic hydrocarbon rings such as benzene ring, polycyclic aromatic hydrocarbon rings, etc. Examples of the polycyclic aromatic hydrocarbon ring include condensed polycyclic aromatic hydrocarbon rings, ring-aggregated aromatic hydrocarbon rings, etc.

[0138] Examples of the fused polycyclic aromatic hydrocarbon ring include fused bicyclic aromatic hydrocarbon rings, fused tricyclic aromatic hydrocarbon rings, and other fused bicyclic to tetracyclic aromatic hydrocarbon rings. Examples of the fused bicyclic aromatic hydrocarbon ring include fused bicyclic C 1-6-1 ... 10-16 Examples of the condensed tricyclic aromatic hydrocarbon ring include anthracene ring, phenanthrene ring and other condensed tricyclic aromatic hydrocarbon rings. 14-20 Aromatic hydrocarbon rings, etc. Preferred condensed polycyclic aromatic hydrocarbon rings are condensed polycyclic C 10-14 Aromatic ring.

[0139] Examples of the ring-aggregated aromatic hydrocarbon ring include biphenyl rings, phenylnaphthalene rings, and binaphthyl rings; and terphenyl rings. Preferred ring-aggregated aromatic hydrocarbon rings are C 12-18 Biaryl ring.

[0140] It should be noted that in this specification and claims, "ring-aggregated aromatic hydrocarbon ring" refers to an aromatic hydrocarbon ring in which two or more ring systems (aromatic hydrocarbon ring systems) are directly connected by a single bond or a double bond, and the number of bonds directly connecting the rings is only one less than the number of ring systems. For example, as described above, biphenyl rings, phenylnaphthalene rings, binaphthyl rings and other biaryl rings are classified as ring-aggregated aromatic hydrocarbon rings even if they have fused polycyclic aromatic hydrocarbon ring skeletons such as naphthalene ring skeletons. Therefore, "ring-aggregated aromatic hydrocarbon rings" are clearly distinguished from "fused polycyclic aromatic hydrocarbon rings" such as naphthalene rings (non-ring-aggregated aromatic hydrocarbon rings).

[0141] As a preferred ring Z 1a and Z 1b , we can cite: C 6-14 Aromatic hydrocarbon ring, more preferably a benzene ring, a naphthalene ring, a biphenyl ring or the like C 6-12 Aromatic hydrocarbon ring, more preferably benzene ring, naphthalene ring, etc. 6-10 The aromatic hydrocarbon ring is particularly preferably a benzene ring.

[0142] Ring Z 1a and Z 1b The types of may be different from each other, but are preferably the same. 1a and Z 1b The substitution position of is not particularly limited.1a When the ring Z is a benzene ring, it can be in any position. 1a When the ring Z is a naphthalene ring, it is either the 1st or 2nd position, preferably the 2nd position. 1a In the case of a biphenyl ring, it is any of the 2-position, 3-position, and 4-position, preferably the 3-position. 1b Same here.

[0143] As R 3a and R 3b The substituent represented by may be: 2a and X 2b The substituents exemplified as the substituents that the divalent hydrocarbon group may have are shown in 3a and R 3b Representative examples include: halogen atoms; hydrocarbon groups such as alkyl, cycloalkyl, aryl, and aralkyl; alkoxy; acyl; nitro; cyano; substituted amino, etc. When the number of substitutions p1 and / or p2 is 1 or more, the preferred group R 3a and / or R 3b , examples include: alkyl, cycloalkyl, aryl, alkoxy, and more preferably: linear or branched C such as methyl 1-6 Alkyl, cyclohexyl, etc. 5-8 Cycloalkyl, phenyl, etc. 6-14 Aryl, methoxy and other straight-chain or branched C 1-4 Among them, linear or branched C 1-4 Alkyl, aryl, preferably linear or branched C 1-3 Alkyl, C 6-10 Aryl, more preferably methyl, etc. 1-2 Alkyl, phenyl. It should be noted that when the group R 3a When it is an aromatic group, the group R 3a Can be used with Ring Z 1a Together they form the above ring aggregate aromatic hydrocarbon ring. 3b and Z 1b Same here.

[0144] Group R 3a and R 3b The substitution numbers p1 and p2 of ring Z can be integers greater than 0, respectively. 1a and Z 1b The type is appropriately selected, and for example, it can be an integer of about 0 to 8. Preferred ranges include integers of 0 to 4, integers of 0 to 3, and integers of 0 to 2, respectively. Among them, 0 or 1 is preferred, and 0 is particularly preferred.

[0145] It should be noted that the substitution numbers p1 and p2 may be different from each other, but are preferably the same. In addition, when the substitution number p1 is 2 or more, in the same ring Z1a 2 or more R substituted 3a The types of p2 and Z can be the same or different. 1b and R 3b In addition, the group R 3a and R 3b The types of may be different from each other, but are preferably the same. In particular, when p1 is 1, ring Z 1a It can be a benzene ring, a naphthalene ring or a biphenyl ring, and the group R 3a It can be methyl. 1b and R 3b In addition, the group R 3a The substitution position is not particularly limited as long as the substitution is in ring Z 1a The 9-position of the fluorene ring and the group [-O-(A 1a O) n1 -] (hereinafter also referred to as ether-containing) bonding position, in the ring Z 1a In the above, substitution is preferably at the ortho position (the carbon atom adjacent to the bonding position of the ether-containing group) of the ether-containing group. 3b , Z 1b and [-O-(A 1b O) n2 -]The same applies.

[0146] The group [-O-(A 1a O) n1 -] in Ring Z 1a The substitution position on ring Z is not particularly limited as long as the substitution 1a When the ring Z 1a When the ring Z is a benzene ring, the substitution position of the ether-containing group is preferably substituted at any one of the 2-position, 3-position, and 4-position of the phenyl group bonded to the 9-position of the fluorene ring, more preferably substituted at the 3-position or 4-position, and particularly preferably substituted at the 4-position. 1a When the ring Z is a naphthalene ring, the ether-containing group is preferably substituted at any of the 5-8 positions of the naphthyl group bonded to the 9-position of the fluorene ring. For example, preferably, the 1-position or 2-position of the naphthalene ring is substituted relative to the 9-position of the fluorene ring (substituted in the relationship of 1-naphthyl or 2-naphthyl), and relative to the substituted position, the 1,5-position, 2,6-position, etc., especially the 2,6-position. 1a When the ring Z is an aromatic ring, the substitution position of the ether-containing group is not particularly limited, and for example, the ether-containing group may be substituted on the aromatic ring bonded to the 9-position of the fluorene or on the aromatic ring adjacent to the aromatic ring. 1a is a biphenyl ring (or ring Z 1a is a benzene ring, p1 is 1, R 3aWhen the 3-position of the biphenyl ring is bonded to the 9-position of the fluorene, the substitution position of the ether-containing group can be, for example, any one of the 2-position, 4-position, 5-position, 6-position, 2'-position, 3'-position, and 4'-position of the biphenyl ring, preferably the 6-position or 4'-position, and particularly preferably the 6-position. 1b O) n2 -]、Z 1b , p2 and R 3b Same here.

[0147] Representative examples of the bisarylfluorene diol unit (B1-2) include: diol units corresponding to 9,9-bis(hydroxyaryl)fluorenes in which n1 and n2 are 0 in the above formula (2A), and 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes in which n1 and n2 are 1 or more, for example, about 1 to 10. It should be noted that in the present specification and claims, "(poly)alkoxy" means both alkoxy and polyalkoxy unless otherwise specified.

[0148] Examples of the 9,9-bis(hydroxyaryl)fluorenes include 9,9-bis(hydroxyphenyl)fluorene, 9,9-bis(alkyl-hydroxyphenyl)fluorene, 9,9-bis(aryl-hydroxyphenyl)fluorene, and 9,9-bis(hydroxynaphthyl)fluorene.

[0149] As 9,9-bis(hydroxyphenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene etc. are mentioned, for example.

[0150] Examples of 9,9-bis(alkyl-hydroxyphenyl)fluorene include 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, and the like. 1-4 Alkyl-hydroxyphenyl]fluorene, etc.

[0151] Examples of 9,9-bis(aryl-hydroxyphenyl)fluorene include 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene and the like. 6-10 Aryl-hydroxyphenyl)fluorene, etc.

[0152] Examples of 9,9-bis(hydroxynaphthyl)fluorene include 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 9,9-bis(5-hydroxy-1-naphthyl)fluorene.

[0153] Examples of the 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, and 9,9-bis[hydroxy(poly)alkoxynaphthyl]fluorene.

[0154] Examples of the 9,9-bis[hydroxy(mono-decyl)C fluorene include 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)phenyl]fluorene, and 9,9-bis[4-(2-hydroxypropoxy)phenyl]fluorene. 2-4 Alkoxy-phenyl]fluorene, etc.

[0155] Examples of the 9,9-bis[alkyl-hydroxy(poly)alkoxyphenyl]fluorene include 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)-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, and the like. 1-4 Alkyl-hydroxy (mono-decyl) C 2-4 Alkoxy-phenyl]fluorene, etc.

[0156] Examples of 9,9-bis[aryl-hydroxy(poly)alkoxyphenyl]fluorene include 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)-3-phenylphenyl]fluorene, and 9,9-bis(4-(2-hydroxypropoxy)-3-phenylphenyl)fluorene. 6-10 Aryl-hydroxy (mono-decyl) C 2-4 Alkoxy-phenyl]fluorene, etc.

[0157] Examples of 9,9-bis[hydroxy(mono-decyl)alkyloxy]fluorene include 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, 9,9-bis[5-(2-hydroxyethoxy)-1-naphthyl]fluorene, 9,9-bis[6-(2-(2-hydroxyethoxy)ethoxy)-2-naphthyl]fluorene, 9,9-bis[6-(2-hydroxypropyloxy)-2-naphthyl]fluorene, and the like. 2-4 Alkoxy-naphthyl]fluorene, etc.

[0158] These bisarylfluorene diol units (B1-2) may be contained alone or in combination of two or more. Among the bisarylfluorene diol units (B1-2), 9,9-bis[hydroxy(mono-hexa)C2-4 Alkoxy C 6-10 9,9-bis[hydroxy(poly)alkoxyaryl]fluorene, more preferably 9,9-bis[hydroxy(mono- or di-)C 2-4 Alkoxy-C 6-10 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. are more preferred. 2-3 Alkoxy-C 6-12 aryl] fluorene, among which 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and the like are preferred. 2-3 Alkoxy-phenyl]fluorene structural unit.

[0159] In the fluorene diol unit (B1), the dialkyl fluorene diol unit (B1-1) and the diaryl fluorene diol unit (B1-2) can be used alone or in combination of two or more. The ratio of the total amount of the dialkyl fluorene diol unit (B1-1) and the diaryl fluorene diol unit (B1-2) to the total amount of the fluorene diol unit (B1) can be, for example, 1 mol% or more, specifically, it can be selected from the range of about 10 to 100 mol%, and as a preferred range, it is preferably 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 preferably 100 mol%, and the fluorene diol unit (B1) contains substantially only the dialkyl fluorene diol unit (B1-1) and / or the diaryl fluorene diol unit (B1-2). When the above ratio is too small, a polyester resin showing negative orientation birefringence and wavelength dispersion may not be formed. From the viewpoint of satisfying the phase difference performance and wavelength dispersion characteristics and environmental resistance reliability in a good balance, it is preferred that the fluorene diol unit (B1) contains only the bisaryl fluorene diol unit (B1-2).

[0160] In addition, the ratio of the fluorene glycol unit (B1) to the total diol unit (B) may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, and as preferred ranges, 30 to 100 mol%, 50 to 99 mol%, 60 to 98 mol%, 70 to 97 mol%, 80 to 96 mol%, and 85 to 95 mol% are preferred in that order. When the ratio of the fluorene glycol unit (B1) is too small, a polyester resin showing negative orientation birefringence and parallel wavelength dispersion may not be formed, and when the above ratio is too large, moldability and workability may be reduced.

[0161] (Poly)alkylene glycol unit (B2)

[0162] The polyester resin may contain a (poly)alkylene glycol unit (B2) represented by the following formula (3) as the diol unit (B) as required. When the (poly)alkylene glycol unit (B2) is contained, the polymerization reactivity of the polyester resin can be improved and the molecular weight can be increased, or the toughness can be improved by a soft chemical structure, so it is effective for preparing a phase difference film with excellent formability and operability. Therefore, it is preferably combined with a diarylfluorene glycol unit (B1-2).

[0163] [Chemistry 9]

[0164]

[0165] (In the formula, A 2 represents a linear or branched alkylene group, and q represents an integer greater than 1).

[0166] In the above formula (3), A 2 The alkylene group represented by the present invention includes, for example, a linear or branched C group 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. 2-12 Alkylene etc. As a preferred alkylene A 2 , the following are straight chain or branched chain C 2-10 Alkylene, linear or branched C 2-8 Alkylene, linear or branched C 2-6 Alkylene, linear or branched C 2-4 Alkylene, more preferably a linear or branched C 2-3 The alkylene group is particularly preferably an ethylene group.

[0167] The repeating number q can be selected from the range of about 1 to 10, and as preferred ranges, 1 to 8, 1 to 6, 1 to 4, 1 to 3, 1 to 2 are preferred, and 1 is particularly preferred. It should be noted that the repeating number q may be an average value (arithmetic mean or arithmetic mean), and the preferred form is the same as the range of the above integer. When q is 2 or more, two or more oxyalkylene groups (-A 2 The types of O-) may be different from each other, but are preferably the same.

[0168] Examples of the diol component corresponding to the (poly)alkylene glycol unit (B2) include alkylene glycol (or alkane diol), polyalkylene glycol (or polyalkane diol), and the like.

[0169] Examples of the alkylene glycol include: 2Compounds corresponding to the alkylene groups exemplified above include, specifically, linear or branched C-alkylene groups 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, and 1,10-decanediol. 2-12 Alkylene glycol, etc., preferably with the above alkylene A 2 The same accordingly.

[0170] Examples of the polyalkylene glycol include: wherein q in the above formula (3) is 2 or more, for example, about 2 to 10, and A 2 The compounds corresponding to the alkylene groups exemplified above include diethylene glycol, dipropylene glycol, triethylene glycol, and di- to di-linear or branched C 2-12 Alkylene glycol, etc., preferably di- to hexa-linear or branched C 2-6 Alkylene glycols, more preferably di- to tetra-linear or branched C 2-4 Alkylene glycol.

[0171] These (poly)alkylene glycol units (B2) may be contained alone or in combination of two or more. As the preferred (poly)alkylene glycol units (B2), from the viewpoint of not easily reducing the heat resistance, preferably a diol unit derived from alkylene glycol, more preferably a linear or branched C 2-6 Alkylene glycol, more preferably a linear or branched C 2-4 Alkylene glycol, among which linear or branched C 2-3 The alkylene glycol is particularly preferably a structural unit derived from ethylene glycol.

[0172] The ratio of the (poly)alkylene glycol unit (B2) to the whole diol unit (B) can be selected from the range of 0 to 100 mol%, for example, 1 to 50 mol%, and as preferred ranges, 3 to 30 mol%, 5 to 20 mol%, 7 to 15 mol%, and 8 to 12 mol% are preferred in that order. When the ratio of the (poly)alkylene glycol unit (B2) is too high, a polyester resin showing negative orientation birefringence and parallel wavelength dispersion may not be formed, and when it is too low, moldability and handleability may be reduced.

[0173] When the fluorene glycol unit (B1) and the (poly) alkylene glycol unit (B2) are combined, the ratio B1 / B2 (molar ratio) can be selected from the range of about 1 / 99 to 99 / 1, and the preferred ranges are 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 85 / 15 to 95 / 5 are particularly preferred. In particular, when the bisaryl fluorene glycol unit (B1-2) and the (poly) alkylene glycol unit (B2) are combined, the ratio B1-2 / B2 (molar ratio) (including preferred embodiments) is the same as that of the above-mentioned ratio of B1 / B2. When the ratio of the fluorene diol unit (B1) or the bisaryl fluorene diol unit (B1-2) is too small, a polyester resin showing negative orientation birefringence and parallel wavelength dispersion may not be obtained. When the ratio is too large, moldability and handleability may be reduced.

[0174] The third diol unit (B3)

[0175] The polyester resin may not contain a third glycol unit (B3) different from the fluorene glycol unit (or the first glycol unit) (B1) and the (poly)alkylene glycol unit (or the second glycol unit) (B2) as the glycol unit (B), but may contain it as needed within a range not impairing the effects of the present disclosure.

[0176] Examples of the third diol unit (B3) include alicyclic diols, aromatic diols [excluding the diol corresponding to the fluorene diol unit (B1)], and constituent units derived from alkylene oxide (alkylene carbonate or halogenated alkanol) adducts of these diol components.

[0177] Examples of the alicyclic diol include cycloalkane diols such as cyclohexanediol; bis(hydroxyalkyl)cycloalkanes such as cyclohexanedimethanol; hydrogenated products of aromatic diols such as bisphenol A and the like, which are exemplified below.

[0178] Examples of the aromatic diol include dihydroxy aromatic hydrocarbons such as hydroquinone and resorcinol; aromatic aliphatic diols such as benzyl alcohol; bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol C, bisphenol G, and bisphenol S; and biphenols such as p,p′-biphenol.

[0179] Examples of the alkylene oxide (corresponding alkylene carbonate or halogenated alkanol) adducts of these diol components include: 2-4 Alkylene oxide adducts, preferably ethylene oxide adducts, propylene oxide adducts, etc. 2-3 The number of added moles of the alkylene oxide adduct is not particularly limited, and specific examples thereof include adducts obtained by adding about 2 to 10 moles of ethylene oxide to 1 mole of a diol such as bisphenol A.

[0180] The diol unit (B) may contain these third diol units (B3) alone or in combination of two or more.

[0181] The ratio of the total amount of the fluorene glycol units (B1) and the (poly)alkylene glycol units (B2) to the total glycol units (B) may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, and as preferred ranges, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, and 95 mol% or more are preferred in that order, and 100 mol% is particularly preferred, and the third glycol unit (B3) is substantially not contained.

[0182] From the viewpoint of easiness in adjusting the birefringence and wavelength dispersion characteristics to a predetermined level, the polyester resin preferably contains a fluorenedicarboxylic acid unit (A1) and a fluorenediol unit (B1), and more preferably contains a fluorenedicarboxylic acid unit (A1), a bisarylfluorenediol unit (B1-2), and a (poly)alkylene glycol unit (B2).

[0183] In the polyester resin, the total amount of the constituent units having a fluorene ring-containing group, i.e., the fluorenedicarboxylic acid units (A1) and the fluorenediol units (B1), may be, for example, 10 mol% or more, and specifically may be selected from the range of about 30 to 100 mol%, and preferably 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%, relative to the total amount of the constituent units of the polyester. When the proportion of the constituent units having a fluorene ring-containing group is too small, a polyester resin showing negative orientation birefringence and wavelength dispersion may not be formed.

[0184] It should be noted that the resin may not contain other constituent units (C) different from the dicarboxylic acid unit (A) and the diol unit (B), but may contain them as needed within the range that does not impair the effects of the present disclosure. As other constituent units (C), for example, constituent units derived from the following components can be cited: hydroxyalkanoic acid or the corresponding lactone, a multifunctional polymer component having three or more carboxyl groups and / or hydroxyl groups, a carbonate bond forming component, etc.

[0185] Examples of the hydroxyalkanoic acid or the corresponding lactone include lactic acid, 3-hydroxybutyric acid, 6-hydroxycaproic acid, and the like. 2-10 Hydroxyalkanoic acid; lactones corresponding to hydroxyalkanoic acid such as ε-caprolactone, etc.

[0186] Examples of the polyfunctional polymer component include trivalent or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid, and trivalent or higher polyols such as glycerol and pentaerythritol, which contain three or more carboxyl groups and / or hydroxyl groups in total.

[0187] As carbonate bond forming component, as long as can form the compound of carbonate bond by reacting with 2 glycol components.That is, "constituent unit from carbonate bond forming component" refers to carbonyl, forms carbonate bond together with the terminal oxygen atom of 2 glycol units adjacent to this carbonyl and bonding.As representative carbonate bond forming component, for example can enumerate: phosgenes such as phosgene, triphosgene, carbonic acid diesters such as diphenyl carbonate etc.

[0188] The ratio of such other constituent units (C) relative to the total amount of the constituent units (the total amount of the dicarboxylic acid units (A), the diol units (B) and the other constituent units (C)) is, for example, 50 mol% or less, and as preferred ranges, 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, and 5 mol% or less, respectively, and it is preferred that other constituent units (C) are substantially not contained. The above ratio may be about 0 to 10 mol%, for example, 0.01 to 1 mol%.

[0189] (Production method and properties of polyester resin)

[0190] The method for producing the polyester resin can be made by conventional methods according to the type of resin or other polymer components (copolymer components), etc. For example, when the polyester resin is a polyester resin, it can be produced by reacting "a dicarboxylic acid component (A) corresponding to each of the above-mentioned dicarboxylic acid units, etc." with "a diol component (B) corresponding to the above-mentioned diol units, etc.", and can be produced by conventional methods, specifically, by melt polymerization methods such as ester exchange method and direct polymerization method, solution polymerization method, interfacial polymerization method, etc., preferably melt polymerization method. It should be noted that the reaction can be carried out in the presence or absence of a solvent according to the polymerization method.

[0191] The ratio (or charging ratio) of the dicarboxylic acid component (A) to 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 necessarily required to be within this range, and at least one component selected from each dicarboxylic acid component (A) and each diol component (B) may be reacted in an excess amount relative to a predetermined introduction ratio. For example, the (poly)alkylene glycol component (B2) such as ethylene glycol distilled from the reaction system may be used in excess of the ratio (or introduction ratio) introduced into the resin.

[0192] The reaction can be carried out in the presence of a catalyst. As the catalyst, a conventional esterification catalyst such as a metal catalyst can be used. As the metal catalyst, for example, a metal compound containing an alkali metal such as sodium; an alkaline earth metal such as magnesium, calcium, and barium; a transition metal such as titanium, manganese, and cobalt; a metal of the 12th group of the periodic table such as zinc and cadmium; a metal of the 13th group of the periodic table such as aluminum; a metal of the 14th group of the periodic table such as germanium and lead; a metal of the 15th group of the periodic table such as antimony can be used. As the metal compound, for example, it can be: an alkoxide; an organic acid salt such as acetate and propionate; an inorganic acid salt such as borate and carbonate; an oxide, etc., and it can also be a hydrate thereof. Representative metal compounds include, for example, germanium compounds such as germanium dioxide, germanium hydroxide, germanium oxalate, tetraethoxygermanium, and n-butoxygermanium; antimony compounds such as antimony trioxide, antimony acetate, and antimony 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; calcium compounds such as calcium acetate monohydrate, and the like.

[0193] These catalysts can be used alone or in combination of two or more. When multiple catalysts are used, each catalyst can be added according to the progress of the reaction. Among these catalysts, manganese acetate tetrahydrate, calcium acetate monohydrate, germanium dioxide, tetrabutoxytitanium (IV) and the like are preferred. The amount of the catalyst used is, for example, 0.01×10 -4 ~100×10 -4 mole, preferably 0.1×10 -4 ~40×10 -4 Moore.

[0194] In addition, the reaction can be carried out in the presence of a stabilizer such as a heat stabilizer or an antioxidant as required. Usually, commonly used heat stabilizers include phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dibutyl phosphate (dibutyl phosphate or dibutyl phosphate), phosphorous acid, trimethyl phosphite, and triethyl phosphite. Among them, dibutyl phosphate is often used. The amount of the heat stabilizer used is, for example, 0.01×10 -4 ~100×10 -4 mole, preferably 0.1×10 -4 ~40×10 -4 Moore.

[0195] The reaction can be carried out in an atmosphere of an inert gas, such as nitrogen; a rare gas such as helium or argon. Alternatively, the reaction can be carried out under reduced pressure, such as 1×10 2 ~1×10 4The ester exchange reaction is preferably carried out under an inert gas atmosphere such as nitrogen, and the polycondensation reaction is preferably carried out under reduced pressure. The reaction temperature can be selected according to the polymerization method. For example, the reaction temperature of the melt polymerization method is 150 to 320°C, preferably 180 to 310°C, and more preferably 200 to 300°C.

[0196] The glass transition temperature Tg of the polyester resin thus obtained may be, for example, in the range of about 80 to 250° C., and the preferred ranges are 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., respectively. When the glass transition temperature is too high, the moldability may be reduced and melt film formation may be difficult. When the glass transition temperature is too low, the environmental resistance reliability (heat resistance and water resistance (humidity resistance), dimensional stability and phase difference stability to heat and moisture) may be reduced, and the reliability (or durability) in a hot and humid environment after being installed in an image display device may be reduced.

[0197] As described later, when forming a retardation film as a multilayer film (laminated film), it is preferred to adjust the glass transition temperature of the polyester resin to near the glass transition temperature of the polyamide resin because the moldability can be effectively improved.

[0198] The weight average molecular weight Mw of the polyester resin can be measured by gel permeation chromatography (GPC) and the like. When converted to polystyrene, it can be selected from a range of about 20,000 to 150,000, for example. As preferred ranges, the following are successively 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. When the weight average molecular weight is too low, the following problems may occur: the moldability such as film forming properties and stretchability is reduced, the film is broken due to stretching, or the mechanical strength of the film is insufficient and the operability is reduced. When the weight average molecular weight is too large, the following problems may occur: the melt viscosity becomes too high and the moldability is reduced.

[0199] In addition, in this specification and claims, the glass transition temperature Tg and the weight average molecular weight Mw can be measured by the method described in the examples mentioned later.

[0200] [Polyamide resin]

[0201] As long as the polyamide resin is a resin that shows positive orientation birefringence and phase difference flat dispersion in its single film (uniaxially stretched film), polyamide resins can be used. As polyamide resins, as long as the main chain has a chemical structure that at least contains amide bonds (or amide groups), polyamide resins, polyamide-imide resins, polyester amide resins, etc. can be cited. These polyamide resins can contain more than two kinds alone or in combination. In these polyamide resins, from the viewpoints of moldability and phase difference performance, polyamide resins are preferred.

[0202] Examples of the polyamide resin exhibiting the above-mentioned properties include polyamide resins containing a structural unit having an alicyclic skeleton (or an alicyclic hydrocarbon group), and preferably polyamide resins containing a structural unit having an alicyclic skeleton in the main chain.

[0203] In the past, cyclic olefin copolymers (COP) were used as resins with alicyclic skeletons in phase difference films. COP has flat dispersion and usually has low phase difference performance. Although the phase difference performance (the ease of phase difference) can be improved by introducing an aromatic ring skeleton into the chemical structure, this will cause the wavelength dispersion characteristics to change significantly from flat dispersion to the direction of wavelength dispersion. Therefore, it is very difficult to take into account both high phase difference performance and flat dispersion.

[0204] However, the inventors of the present invention have discovered that in a polyamide-based resin having an alicyclic skeleton, it is possible that the amide group present in the main chain can increase the phase difference without significantly changing the wavelength dispersion characteristics in the forward dispersion direction, and unexpectedly can achieve both high phase difference expression and flat dispersion. Furthermore, by combining with the above-mentioned specified polyester-based resin, it is possible to achieve both high phase difference expression and reverse wavelength dispersion. In particular, it is possible to form a phase difference film that has an excellent balance between thinness, phase difference and reverse wavelength dispersion while improving formability (or productivity) and environmental resistance reliability.

[0205] It should be noted that the alicyclic skeleton can be any aliphatic hydrocarbon ring (a non-aromatic hydrocarbon ring or a hydrocarbon ring without an aromatic ring), and may contain multiple bonds such as double bonds in the ring, but preferably does not contain multiple bonds. The aliphatic hydrocarbon ring can be roughly divided into a monocyclic aliphatic hydrocarbon ring and a cross-linked aliphatic hydrocarbon ring.

[0206] Examples of the monocyclic aliphatic hydrocarbon ring include a cycloalkane ring and a cycloalkene ring. Examples of the cycloalkane ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and the like. 3-20 Examples of the cycloalkene ring include cyclopentene ring, cyclohexene ring, and the like. 3-20 Cycloolefin ring, etc.

[0207] Examples of the cross-linked cyclic aliphatic hydrocarbon ring include a cross-linked cyclic cycloalkane ring and a cross-linked cyclic cycloolefin ring. Examples of the cross-linked cyclic cycloalkane ring include a decalin ring, a norbornane ring, an adamantane ring, a tricyclodecane ring, a tetracyclododecane ring, and the like. 7-20 Dicycloalkane rings to tetracycloalkane rings, etc. Examples of the tricyclodecane ring include: tricyclo[5.2.1.0 2,6 ] decane ring, etc. Examples of the tetracyclododecane ring include: tetracyclo[4.4.0.1 2,5 .1 7,10 As the cross-linked cyclic olefin ring, there can be mentioned: norbornene ring, tricyclodecene ring, tetracyclododecene ring and the like C 7-20 Di- to tetracyclic olefin rings, etc.

[0208] The constituent unit having an alicyclic skeleton may contain these alicyclic skeletons alone or in combination of two or more in the chemical structure. Among these alicyclic skeletons, a cycloalkane ring or a cross-linked cycloalkane ring without multiple bonds is preferred. From the viewpoint of flat dispersibility, a monocyclic cycloalkane ring is preferred, and a C 5-10 Cycloalkane ring, among which cyclohexane ring is preferred. 5-8 Cycloalkane ring.

[0209] The polyamide resin can be formed by polymerization of a diamine component and a dicarboxylic acid component, polymerization of an aminocarboxylic acid component and / or a lactam component, polymerization of a diamine component and a dicarboxylic acid component with an aminocarboxylic acid component and / or a lactam component, etc., and according to its form, at least one of the polymer components forming the polyamide resin has an alicyclic skeleton. Therefore, the polyamide resin can be formed by containing at least one polymer component selected from the alicyclic diamine component, alicyclic dicarboxylic acid component and alicyclic aminocarboxylic acid component described later. As a representative polyamide resin, it is preferably formed by a polymer component containing a diamine component (D) and a dicarboxylic acid component (E), and at least the diamine component has an alicyclic skeleton.

[0210] (Diamine unit (D))

[0211] Alicyclic diamine unit (D1)

[0212] The diamine unit (D) preferably contains an alicyclic diamine unit (D1) having an alicyclic skeleton. The alicyclic diamine unit (D1) may be a diamine unit having an alicyclic skeleton as exemplified above in its chemical structure, for example, a C-containing diamine such as cyclohexanediamine. 5-10 Cycloalkane diamine, bis(aminomethyl)cyclohexane and other bis(amino C 1-4 Alkyl)C 5-10 The diamine unit of cycloalkane or the like preferably contains at least a diamine unit represented by the following formula (4).

[0213] [Chemistry 10]

[0214]

[0215] (Where Y 1 represents a direct bond or a divalent hydrocarbon group which may have a substituent, R 4a and R 4b Each independently represents a substituent, and r1 and r2 each independently represent an integer of 0 to 4.

[0216] In the above formula (4), Y 1 It may be a direct bond, but is preferably a divalent hydrocarbon group which may have a substituent. The divalent hydrocarbon group may be a divalent aromatic hydrocarbon group such as a phenylene group, but is preferably a divalent alicyclic hydrocarbon group such as a cyclohexylene group or a divalent aliphatic hydrocarbon group from the viewpoint of flat dispersibility, and is particularly preferably a divalent aliphatic hydrocarbon group.

[0217] As Y 1 The divalent aliphatic hydrocarbon group represented by the present invention may be, for example, a straight-chain or branched alkenylene group (specifically, a straight-chain or branched C-alkylene group such as vinylene, 1-methylvinylene, propenylene, 1-butenylene, 2-butenylene, 1-pentenylene, 2-pentenylene, etc.) 2-20 alkylene); linear or branched alkynylene (specifically, ethynylene, propynylene, 3-methyl-1-propynylene, butynylene, 2-pentynylene, 2-hexynylene, 3-heptynylene, 4-octynylyene, 4-nonynylene, 5-decynylene, 6-undecynylene, 6-dodecynylene, etc. linear or branched C 2-20 alkynylene); straight-chain or branched alkane-di- or trimethylene (specifically, 1,3-butanedi-, 2,4-pentanedi-, 1,3,5-hexanetri-, etc.), preferably a straight-chain or branched alkylene.

[0218] As Y 1 The linear or branched alkylene group represented by the present invention includes, for example, a linear or branched C group such as methylene, ethylene, methylmethylene (ethylene), propylene, trimethylene, propane-2,2-diyl (dimethylmethylene), etc. 1-20 Alkylene, etc., preferably the following linear or branched C 1-10 Alkylene, linear or branched C 1-6 Alkylene, linear or branched C 1-4 Alkylene, linear or branched C 1-3 Alkylene, linear or branched C 1-2 The alkylene group is more preferably a methylene group.

[0219] In addition, as Y 1The substituents that the divalent hydrocarbon group represented by may have include aryl groups such as phenyl, cycloalkyl groups such as cyclohexyl, 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, and particularly preferably 0. Examples of the divalent hydrocarbon group having a substituent include 1-phenylethylene, 1-phenylpropane-1,2-diyl, etc. It should be noted that Y 1 It is preferably a linear or branched alkylene group having no substituent.

[0220] As R 4a and R 4b The substituent represented by may be a non-reactive group or a non-polymerizable substituent inert to the polymerization reaction, for example: 2a and X 2b The same groups as those exemplified as the substituents that the divalent hydrocarbon group may have in the above substituents. Among these substituents, alkyl groups are preferred, and linear or branched C groups such as methyl, ethyl, propyl, and isopropyl are more preferred. 1-5 Alkyl, more preferably linear or branched C 1-4 Alkyl, among which linear or branched C 1-3 Alkyl, particularly preferably a linear or branched C 1-2 alkyl.

[0221] R 4a and R 4b The number of substitutions r1 and r2 can be selected from the range of integers of 0 to 3, for example, preferably 0 to 2, more preferably 0 or 1, among which 0 is preferred, and both r1 and r2 are particularly preferred to be 0. When r1 is 2 or more, two or more R 4a The types of r2 and R 4b The same is true. In addition, R substituted on different cyclohexane rings 4a and R 4b The types may be the same or different from each other.

[0222] Representative diamine units represented by the formula (4) include structural units derived from bis(aminocyclohexyl)alkanes, such as structural units derived from 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. 1-6 Alkyl-cyclohexyl)C 1-6 The building blocks of alkanes, etc.

[0223] The diamine units represented by the above formula (4) may be used alone or in combination of two or more. Among the diamine units represented by the above formula (4), the constituent units derived from bis(aminocyclohexyl)alkane are preferred, and bis(aminocyclohexyl)C 1-4 Alkanes, more preferably bis(aminocyclohexyl)C 1-3 Alkanes, among which bis(aminocyclohexyl)C such as bis(4-aminocyclohexyl)methane are preferred. 1-2 The building blocks of alkanes.

[0224] The alicyclic diamine units (D1) may be contained alone or in combination of two or more. In the alicyclic diamine units (D1), the ratio of the diamine units represented by the above formula (4) may be, for example, 1 mol% or more relative to the total alicyclic diamine units (D1), specifically, it may be selected from the range of about 10 to 100 mol%, and as preferred ranges, preferably 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 preferably 100 mol%, and the alicyclic diamine units (D1) are substantially only the diamine units represented by the above formula (4). When the above ratio is too small, a polyamide resin showing positive orientation birefringence and flat dispersion may not be formed.

[0225] Second diamine unit (D2)

[0226] The polyamide resin may not contain a diamine unit (second diamine unit (D2)) different from the alicyclic diamine unit (or first diamine unit) (D1) as the diamine unit (D), but may contain it as necessary within a range not impairing the effects of the present disclosure.

[0227] Examples of the second diamine unit (D2) include structural units derived from an aliphatic diamine component, an aromatic (or aromatic aliphatic) diamine component, and the like.

[0228] Examples of the aliphatic diamine component include linear or branched C-type aliphatic diamines such as tetramethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, 2-methyloctamethylenediamine, trimethylhexamethylenediamine, decamethylenediamine, and dodecamethylenediamine. 2-20 Alkylene diamine, etc.

[0229] Examples of the aromatic (or aromatic aliphatic) diamine component include diamino aromatic hydrocarbons, and specific examples include diamino C such as m-phenylenediamine and p-phenylenediamine. 6-14 Aromatic hydrocarbons; bis(aminoalkyl)aromatic hydrocarbons, specifically bis(aminoC 1-4 Alkyl) aromatic hydrocarbons, etc.

[0230] These second diamine units (D2) can be used alone or in combination of two or more.

[0231] The ratio of the alicyclic diamine unit (D1) to the total diamine unit (D) may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, preferably 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 preferably 100 mol%, and the diamine unit (D) substantially contains only the alicyclic diamine unit (D1). When the ratio is too low, a polyamide resin showing positive orientation birefringence and flat dispersion may not be formed.

[0232] (Dicarboxylic acid unit (E))

[0233] The dicarboxylic acid unit (E) may or may not contain an alicyclic dicarboxylic acid unit (E2) described below, but preferably contains an aliphatic dicarboxylic acid unit (E1).

[0234] Aliphatic dicarboxylic acid unit (E1)

[0235] When containing an aliphatic dicarboxylic acid unit (E1), the glass transition temperature Tg of the polyamide resin can be adjusted to an appropriate range, and the moldability can be easily improved. Therefore, when combined with a constituent unit having an alicyclic skeleton, such as the above-mentioned alicyclic diamine unit (D1), the moldability can be effectively improved even if it has an alicyclic skeleton.

[0236] Examples of the aliphatic dicarboxylic acid component forming the aliphatic dicarboxylic acid unit (E1) include: 1 The specifically exemplified dicarboxylic acid components include a divalent aliphatic hydrocarbon group to which two carboxyl groups are bonded.

[0237] These aliphatic dicarboxylic acid components can be used alone or in combination of two or more. Among these aliphatic dicarboxylic acid components, linear or branched alkane dicarboxylic acid components are preferred. Examples of linear or branched alkane dicarboxylic acid components include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid and the like. 1-20 Alkane-dicarboxylic acid components, such as adipic acid, sebacic acid, 1,10-decanedicarboxylic acid, etc., are preferably linear or branched C 4-16 The alkane-dicarboxylic acid component is preferably a linear or branched C 6-14 The alkane-dicarboxylic acid component is particularly preferably a linear or branched C 8-12 Alkanedicarboxylic acid component: Among linear or branched alkanedicarboxylic acid components, linear alkanedicarboxylic acid components are preferred.

[0238] The ratio of the aliphatic dicarboxylic acid units (E1) to the total dicarboxylic acid units (E) may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, preferably 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 preferably 100 mol%, and the dicarboxylic acid units (E) are substantially only the aliphatic dicarboxylic acid units (E1). When the above ratio is too small, the moldability may be reduced.

[0239] Alicyclic dicarboxylic acid unit (E2)

[0240] The dicarboxylic acid unit (E) does not necessarily need to contain the alicyclic dicarboxylic acid unit (E2), and for example, when the diamine unit (D) contains the alicyclic diamine unit (D1), it may not contain the alicyclic diamine unit (E2). However, it may be contained as a structural unit having an alicyclic skeleton as necessary.

[0241] Examples of the alicyclic dicarboxylic acid unit (E2) include dicarboxylic acid units having one or more of the above-mentioned aliphatic hydrocarbon rings exemplified as alicyclic skeletons. The above-mentioned alicyclic skeletons may have one or more of them alone or in combination. When there are more than one alicyclic skeletons, the alicyclic skeletons may be directly bonded to each other or bonded via "Y in the above formula (4)". 1 In addition, the alicyclic skeleton may have a substituent such as an alkyl group, and specifically, a C 1-6 alkyl.

[0242] Representative alicyclic dicarboxylic acid units (E2) include constituent units derived from alicyclic dicarboxylic acid components specifically exemplified as the second dicarboxylic acid units (A2). These alicyclic dicarboxylic acid units (E2) may be contained alone or in combination of two or more. Preferred alicyclic dicarboxylic acid units (E2) include cycloalkane dicarboxylic acids, more preferably 1,4-cyclohexane dicarboxylic acid, etc. 5-10 Cycloalkane-dicarboxylic acids.

[0243] The third dicarboxylic acid unit (E3)

[0244] The polyamide resin may not contain a dicarboxylic acid unit (third dicarboxylic acid unit) (E3) different from the aliphatic dicarboxylic acid unit (or the first dicarboxylic acid unit) (E1) and the alicyclic dicarboxylic acid unit (or the second dicarboxylic acid unit) (E2) as the dicarboxylic acid unit (E), but may contain it as needed within a range not impairing the effects of the present disclosure.

[0245] Examples of the third dicarboxylic acid unit (E3) include constituent units derived from aromatic dicarboxylic acid components. Examples of the aromatic dicarboxylic acid components include constituent units derived from aromatic hydrocarbon rings (e.g., benzene rings, naphthalene rings, anthracene rings, fluorene rings, etc.) 6-20 The aromatic dicarboxylic acid component may have one or more of the above aromatic hydrocarbon rings, or may have two or more of them alone or in combination. When there are multiple aromatic hydrocarbon rings, the aromatic hydrocarbon rings may be directly bonded to each other or connected via "Y in the above formula (4)". 1 In addition, the above aromatic hydrocarbon ring skeleton may have a substituent, such as an alkyl group, a cycloalkyl group, etc., and specifically, may have a C alkyl group such as a methyl group. 1-6 Alkyl, cyclohexyl, etc. 3-6 Cycloalkyl, etc.

[0246] Typical examples of the aromatic dicarboxylic acid component include the aromatic dicarboxylic acid components specifically exemplified as the second dicarboxylic acid unit (A2), for example, benzene dicarboxylic acid components such as isophthalic acid and terephthalic acid.

[0247] These third dicarboxylic acid units (E3) may be contained alone or in combination of two or more.

[0248] The total amount of the aliphatic dicarboxylic acid units (E1) and the alicyclic dicarboxylic acid units (E2) may be, for example, 1 mol% or more, specifically, may be selected from the range of about 10 to 100 mol%, preferably 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 preferably 100 mol%, and the dicarboxylic acid units (E) substantially contain only the aliphatic dicarboxylic acid units (E1) and / or the alicyclic dicarboxylic acid units (E2). When the above ratio is too small, the moldability may be reduced, or a polyamide resin showing positive orientation birefringence and flat dispersion may not be formed.

[0249] (Aminocarboxylic acid (or lactam) unit (F))

[0250] The polyamide-based resin may or may not contain the aminocarboxylic acid (or corresponding lactam) unit (F).

[0251] Alicyclic aminocarboxylic acid unit (F1)

[0252] The aminocarboxylic acid unit (F) may or may not contain an alicyclic aminocarboxylic acid unit (F1). Examples of the alicyclic aminocarboxylic acid unit (F1) include a structural unit derived from an aminocycloalkane carboxylic acid component, specifically, a structural unit derived from an amino C such as aminocyclohexane carboxylic acid. 5-10Constituent units of cycloalkane-carboxylic acid components, etc. These alicyclic aminocarboxylic acid units (F1) may be contained alone or in combination of two or more.

[0253] Second aminocarboxylic acid unit (F2)

[0254] The polyamide resin may not contain an aminocarboxylic acid unit (second aminocarboxylic acid unit) (F2) different from the alicyclic aminocarboxylic acid unit (or first aminocarboxylic acid unit) (F1) as the aminocarboxylic acid unit (F), but may contain it as necessary within a range not impairing the effects of the present disclosure.

[0255] Examples of the second aminocarboxylic acid unit (F2) include structural units derived from an aliphatic aminocarboxylic acid component (or a corresponding lactam component) and an aromatic aminocarboxylic acid component.

[0256] Examples of the aliphatic aminocarboxylic acid component include amino C such as 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. 2-20 Alkyl carboxylic acid components, preferably amino C 4-16 Alkyl carboxylic acid component, more preferably amino C 5-11 Alkyl carboxylic acid component. Examples of the corresponding lactam component include 4- to 12-membered ring lactams such as ε-caprolactam and ω-laurolactam, and preferably 7- to 12-membered ring lactams.

[0257] As an aromatic aminocarboxylic acid component, aminoaromatic carboxylic acid, such as aminobenzoic acid, etc. are mentioned, for example.

[0258] These second aminocarboxylic acid units (F2) may be contained alone or in combination of two or more.

[0259] The ratio of the total amount of the diamine units (D) and the dicarboxylic acid units (E) forming the polyamide resin can be, for example, 1 mol% or more, and specifically can be selected from the range of about 10 to 100 mol%, with respect to the entire constituent units of the polyamide resin. As preferred ranges, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, and 95 mol% or more are preferred in that order, and 100 mol% is particularly preferred, and the polyamide resin substantially contains only the diamine units (D) and the dicarboxylic acid units (E).

[0260] In addition, the polyamide resin only needs to contain a structural unit having an alicyclic skeleton, and the total amount of the alicyclic diamine unit (D1), the alicyclic dicarboxylic acid unit (E2) and the alicyclic aminocarboxylic acid unit (F1) may be, for example, 1 mol% or more, and specifically may be selected from the range of about 10 to 100 mol%, and the preferred ranges are 15 to 90 mol%, 20 to 80 mol%, 30 to 70 mol%, 40 to 60 mol%, and more preferably 45 to 55 mol%. When the above ratio is too small, a polyamide resin showing positive orientation birefringence and flat dispersion may not be formed, and when the above ratio is too large, moldability may be reduced.

[0261] Preferred polyamide resins are polyamide resins containing alicyclic diamine units (D1) and aliphatic dicarboxylic acid units (E1), more preferably polyamide resins containing diamine units represented by the above formula (4) and constituent units derived from a linear or branched alkane dicarboxylic acid component, and even more preferably polyamide resins containing constituent units derived from bis(aminocyclohexyl)alkane and constituent units derived from a linear or branched C 4-16 The polyamide resin containing the constituent units of the alkane-dicarboxylic acid component is preferably a polyamide resin containing a bis(aminocyclohexyl)C 1-4 The building blocks of alkanes are derived from straight or branched C 8-12 The polyamide resin containing the structural unit of the alkane dicarboxylic acid component is particularly preferably derived from bis(aminocyclohexyl) C such as bis(4-aminocyclohexyl) methane. 1-3 The structural units of alkanes and straight-chain C 8-12 A polyamide resin having a structural unit of an alkane dicarboxylic acid component.

[0262] The polyamide resin can be produced by a known method, or a commercial product can be used, such as "Trogamid CX7323" manufactured by Daicel Evonik, "Grill Amid TR90" manufactured by EMS-Chemie, "Lilsan G350" and "Lilsan G850" manufactured by Arkema.

[0263] The glass transition temperature Tg of the polyamide resin may be, for example, in the range of about 80 to 250° C., and the preferred ranges are 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., respectively. When the glass transition temperature is too high, the moldability may be reduced or melt film formation may become difficult. When the glass transition temperature is too low, the environmental resistance reliability (heat resistance and water resistance (humidity resistance), dimensional stability and phase difference stability to heat and moisture) may be reduced, and the reliability (or durability) in a hot and humid environment after being installed in an image display device may be reduced.

[0264] As described later, when forming a retardation film as a multilayer film (laminated film), it is preferred to adjust the glass transition temperature of the polyamide resin to near the glass transition temperature of the polyester resin because the moldability can be effectively improved.

[0265] The weight average molecular weight Mw of the polyamide resin can be measured by gel permeation chromatography (GPC) and the like, and when converted to polystyrene, can be selected from a range of about 20,000 to 100,000, for example. When the weight average molecular weight is too low, the following problems may occur: the moldability such as film forming property and stretchability is reduced, the film may break due to stretching, or the mechanical strength of the film is insufficient and the operability is reduced. When the weight average molecular weight is too large, the following problems may occur: the melt viscosity becomes too high and the moldability is reduced.

[0266] [Phase difference film]

[0267] (constitute)

[0268] The phase difference film only needs to contain at least the above-mentioned polyester resin and polyamide resin, but as long as it does not hinder the effect of the present disclosure, it may contain one or more other conventional thermoplastic resins, but preferably does not contain them. The proportion of other conventional thermoplastic resins, relative to the total amount of the above-mentioned polyester resin and polyamide resin, is, for example, 30% by mass or less, preferably 10% by mass or less, and more preferably 0 to 5% by mass.

[0269] In addition, as long as the effect of the present disclosure is not hindered, the phase difference film may also contain various additives. As additives, for example: plasticizers such as esters, phthalic acid compounds, epoxy compounds, and sulfonamides; flame retardants such as inorganic flame retardants, organic flame retardants, and colloidal flame retardants; stabilizers such as antioxidants, ultraviolet absorbers, and thermal stabilizers; antistatic agents; fillers such as oxide-based inorganic fillers, non-oxide-based inorganic fillers, and metal powders; foaming agents; defoamers; lubricants; natural waxes, synthetic waxes, straight-chain fatty acids or their metal salts, amides, and other release agents; slip agents, specifically, inorganic particles such as silicon dioxide, titanium oxide, calcium carbonate, clay, mica, and kaolin; organic particles such as (meth) acrylic resins and (cross-linked) styrene resins; compatibilizers, etc. These additives can be used alone or in combination of two or more. These additives can be added by using conventional methods, such as melt kneading methods using a single-screw or twin-screw extruder. The total amount of the additives relative to the total amount of the polyester resin and the polyamide resin is, for example, 30 mass % or less, preferably 10 mass % or less, and more preferably 0 to 5 mass %.

[0270] The phase difference film may be a single-layer film containing the polyester resin and the polyamide resin, but preferably a multilayer film (or laminated film). In the case of a multilayer film, the polyester resin and the polyamide resin may be contained in the same layer in the multilayer film. From the perspective of environmental resistance reliability and easy adhesion when laminated with other optical elements (or optical films) such as polarizers, it is preferred that each layer contains each resin, that is, preferably a laminated film having a first layer (polyester resin layer) containing the polyester resin and a second layer (polyamide resin layer) containing the polyamide resin.

[0271] In the first layer, the proportion of the polyester resin can be, for example, 1% by mass or more relative to the total resin component forming the first layer, and can be specifically selected from the range of about 10 to 100% by mass. As preferred ranges, the following are preferably 30% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, and 95% by mass or more, and more preferably 100% by mass. The resin component in the first layer substantially contains only the polyester resin. In addition, the proportion of the polyamide resin in the second layer (relative to the total resin component forming the second layer) corresponds to the proportion of the polyester resin in the first layer, and both are the same, including the preferred embodiment. It is preferred that the resin component in the second layer substantially contains only the polyamide resin.

[0272] In addition, in the case of a multilayer film, the phase difference film only needs to include at least one first layer and at least one second layer, and may also include multiple first layers and / or multiple second layers. In addition, as required, the phase difference film may include "a third layer that does not contain a polyester resin and a polyamide resin", or may not contain it.

[0273] The number of layers in the case of a multilayer film can be selected, for example, from the range of about 2 to 10 layers, and preferred ranges are 2 to 8 layers, 2 to 6 layers, 2 to 4 layers, 2 to 3 layers, and more preferably 3 layers.

[0274] In the case of a three-layer structure, it is preferred that a three-layer structure (two three-layer structures) is formed by stacking a surface layer formed by the same resin on both sides of the core layer located in the center, and more preferably a three-layer structure in which the thickness (average thickness) of the surface layer on both sides is approximately the same. In a multilayer film, when there is a difference in shrinkage force after molding between the resins forming each layer, the multilayer film may curl and the operability may be reduced, but by setting the above-mentioned three-layer structure, the difference in shrinkage force is offset by the surface layers on both sides, thereby effectively suppressing the curling of the phase difference film after molding.

[0275] When it is a three-layer structure, although the core layer can be formed as the first layer (polyester resin layer) and the surface layer on both sides can be formed as the second layer (polyamide resin layer), it is preferred to form a three-layer structure of the first layer as the surface layer on both sides of the second layer as the core layer. By configuring the second layer formed by the polyamide resin with high water absorption rate as the core layer inside, and configuring the polyester resin layer as the surface layer on the outside, the environmental reliability (dimensional stability and phase difference stability) of moisture (or under a humid and hot environment) can be effectively improved. In addition, when stacked with other optical elements such as polarizing elements (or polarizers), when the surface layer (outermost layer) is a polyester resin layer, it is preferred from the viewpoint of easy adhesion, especially even when stacked with a polarizing element formed by a PVA film with low water resistance, when the surface layer is a polyester resin layer, the reduction of the optical properties of the polarizing element can be effectively suppressed.

[0276] The phase difference film is formed by combining a specified polyester resin and a specified polyamide resin, so that it can take into account both excellent (or appropriate) reverse wavelength dispersion and high phase difference. That is, even in the form of a multilayer film, the phase difference film showing the desired phase difference and reverse wavelength dispersion can be formed thinner. Therefore, the film thickness (average thickness) of the phase difference film can be, for example, about 20 to 70 μm, and as a preferred range, the following are 25 to 60 μm, 30 to 60 μm, 30 to 50 μm, 30 to 45 μm, and more preferably 30 to 40 μm. It should be noted that in this specification and the claims, the film thickness (average thickness) can be measured by the method described in the embodiments described later.

[0277] When the thickness of the film is too thin, the following problems may occur: the winding property deteriorates in the film making process (easy to wrinkle or tear, difficult to wind), it cannot be stably wound, and it breaks in the stretching process. When the thickness of the film is too thick, it may not be possible to meet the thinning requirements of the phase difference film. In addition, when the thickness of the film is too thick, the following problems may occur: when stress is generated due to shrinkage, etc. in a hot and humid environment, an excessive load is applied to the film, the phase difference changes significantly, and the optical properties are reduced (environmental reliability is reduced). Furthermore, when used in conjunction with a polarizing element (or polarizer), warping is easily generated due to drying in the bonding process, and the optical properties of the polarizing element may be reduced.

[0278] When the retardation film is a multilayer film comprising a first layer and a second layer, the ratio of the total thickness of the first layer (the total value of the average thickness of each first layer) to the total thickness of the second layer (the total value of the average thickness of each second layer) can be selected from, for example, the former / the latter = 0.1 / 1 to 100 / 1, specifically in the range of about 0.3 / 1 to 50 / 1. As preferred ranges, the following are, in order, 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. When preparing the 1 / 4 wave plate described later, it is more preferably 2 / 1 to 5 / 1, and further preferably 2 / 1 to 4.5 / 1. When preparing the retardation film for VA-LCD described later, it is more preferably 2 / 1 to 5.5 / 1, and further preferably 2.2 / 1 to 5 / 1.

[0279] It should be noted that 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 mostly the same as that of the laminated film (original film (raw film) or unstretched film) before stretching, so the above ratio can be the ratio in the original film. When the total thickness of the first layer is too thin relative to the total thickness of the second layer, excellent reverse wavelength dispersion may not be obtained, and when it is too thick, reverse wavelength dispersion may not be obtained. In addition, when the thickness of the first layer is too thick, it may not be possible to prepare a 1 / 4 wave plate.

[0280] (Manufacturing method, characteristics and uses)

[0281] The phase difference film can be produced by at least undergoing the following steps: a film forming step of forming the polyester resin and the polyamide resin into films, and a stretching step of stretching the raw film obtained in the film forming step.

[0282] As the film-making method, for example, cast method (solution casting method or solution casting method), extrusion method, calendaring method, etc. can be mentioned. As the extrusion method, melt extrusion methods such as inflation method and T-die method can be mentioned. From the viewpoint of not only excellent formability but also being able to prevent the reduction of optical properties caused by residual solvent, melt extrusion methods such as T-die method are preferred.

[0283] In addition, when the phase difference film is a multilayer film, the first layer comprising the polyester resin and the second layer comprising the polyamide resin can be respectively film-formed and stretched and then laminated, but from the viewpoint of formability (or productivity), it is preferred to co-stretch the laminated film (original film) obtained by coextrusion. In such a method, not only can the film-forming and stretching steps of each layer and the step of laminating each layer be omitted, but also the defects (poor lamination) caused by the optical axis offset of each layer can be effectively reduced.

[0284] Representative film-making methods using co-extrusion include the following methods: drying each granular resin to a moisture content of, for example, less than 100 ppm, then measuring each resin granule and additive, mixing and supplying them to an extruder, using a slit-shaped die (T-die) to merge each molten resin and melt-extrude it from the die into a sheet to form an original film, etc.

[0285] The melting temperature of each resin in the extruder is preferably about Tg+50 to Tg+180° C., and more preferably Tg+80 to Tg+150° C. relative to the glass transition temperature Tg of each resin. If the melting temperature in the extruder is too low, the fluidity of the resin may be insufficient, and conversely, if the melting temperature is too high, the resin may deteriorate.

[0286] Each resin melted in the extruder can be continuously supplied to the die head via a filter, a gear pump, etc. as needed, or can be filtered with high precision to effectively remove impurities contained in each molten resin. The filter material used in the high precision filtration of the molten resin is not particularly limited, but a filter material of a stainless steel sintered body is preferred because of its excellent removal performance.

[0287] Examples of the slit-shaped die (T-die) include a multi-manifold die and a feed block die. From the viewpoint of precisely controlling the layer thickness, a multi-manifold die of a T-die is preferably designed according to the viscosity of each resin.

[0288] The average thickness (total thickness) of the original film (laminated film obtained by coextrusion) obtained in the film-making process can be selected from a range of about 10 to 1000 μm, and as a preferred range, the following are 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. When the average thickness of the original film is too thick, the phase difference film may not be fully thinned. When the average thickness is too thin, the winding property may deteriorate (difficult to wind), it may not be stably wound, and it may break in the stretching process, etc. It should be noted that the average thickness can be measured by the method described in the embodiments described later.

[0289] In the stretching step, each resin film obtained in the film forming step may be stretched. However, as described above, from the viewpoint of moldability, it is preferred to co-stretch the coextruded film obtained in the film forming step.

[0290] In the co-stretching, the difference in glass transition temperature Tg between the resins, especially the difference in Tg between the polyester resin and the polyamide resin, is preferably small. Therefore, the difference in Tg between the polyester resin and the polyamide resin can be adjusted to a range of about 0 to 30°C, and the preferred ranges are 0 to 20°C, 0 to 15°C, 0 to 10°C, 0 to 8°C, and 0 to 5°C. When the difference in Tg is within such a range, even a multilayer film can be easily formed into a phase difference film with desired characteristics and thinned.

[0291] In detail, the stretching conditions such as the stretching temperature, stretching speed, and stretching ratio in the co-stretching are usually determined based on the results of the stretching experiment of the single film (individual film) of each layer. That is, the stretching conditions are studied from the phase difference, wavelength dispersion characteristics, thickness and other characteristics of the individual films of each layer stretched under the same stretching conditions so that the individual films can have the desired characteristics when overlapped. However, when the difference in glass transition temperature Tg between the resins is too large, there may be the following problems: the range of stretching conditions that can be adjusted to the desired characteristics becomes narrower, and the moldability (or productivity) decreases, or it cannot be molded into the desired characteristics, or it is difficult to stretch at all.

[0292] In the present specification and claims, the difference in Tg when a total of three or more types of the polyester resin and the polyamide resin are included means the difference between the resin showing the largest Tg and the resin showing the smallest Tg.

[0293] Examples of the stretching method include conventional methods such as inter-roll stretching, heat roll stretching, compression stretching, and tenter stretching. The stretching may be uniaxial stretching or biaxial stretching.

[0294] These stretching methods, as well as stretching conditions such as stretching temperature, stretching ratio, and stretching speed can be appropriately selected according to the characteristics and uses required by the phase difference film. For example, when preparing a wave plate such as a quarter wave plate, especially a broadband quarter wave plate used in an organic EL display, a uniaxial stretching can be performed. In addition, when preparing a phase difference film for VA-LCD, a biaxial stretching can be performed.

[0295] (1 / 4 wave plate)

[0296] As uniaxial stretching, it can be either fixed-end uniaxial stretching in which the length in the direction (width direction) perpendicular to the stretching direction is maintained or fixed (or necking (shrinkage) is suppressed) to be constant for stretching, or free-end uniaxial stretching in which stress is not applied in the width direction of the film for stretching. Among them, fixed-end uniaxial stretching as tenter stretching is preferred from the viewpoint of less necking and easy adjustment of physical property values.

[0297] In addition, the stretching direction in the uniaxial stretching can be either a longitudinal stretching stretched roughly parallel to the length direction of the film, or a transverse stretching stretched in a perpendicular width direction, or an oblique stretching stretched at an oblique angle relative to the length direction of the film. Among them, oblique stretching is preferred. The angle between the direction (stretching direction) of the slow axis in the film plane (the axis with the largest refractive index in the film plane) and the length direction of the film can be selected from, for example, a range of about 30 to 60°, preferably 35 to 55°, more preferably 40 to 50°, further preferably 42 to 48°, and particularly preferably about 45°. In such an obliquely stretched phase difference film, when it is bonded to a polarizer such as a linear polarizer by a roll-to-roll method, since it can be easily adjusted so that the slow axis is at an angle of 45° relative to the absorption axis of the polarizer, when manufacturing a circular polarizer, it is not necessary to bond by cutting and bonding in batches, which is particularly preferred from the viewpoint of excellent formability (or productivity).

[0298] When the minimum Tg value of all the resin components contained in each layer is defined as Tg min When the stretching temperature is, for example, Tg min -10~Tg min +20℃, as the preferred range, the following are 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 +9°C. As a specific temperature, for example, it is 117 to 147°C, and as a preferred range, the following are 122 to 144°C, 127 to 142°C, 130 to 140°C, 132 to 138°C, 133 to 137°C, and 134 to 136°C. When the stretching temperature is too high, it is not only difficult to show the desired phase difference, but also the film cannot be stretched uniformly, and the film thickness becomes uneven. When the stretching temperature is too low, it is not only difficult to show the desired phase difference, but also the film may break.

[0299] The stretching ratio can be selected from a range of about 1.1 to 10 times, for example, as a preferred range, the following are 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. When the stretching ratio is too low, the desired phase difference may not be obtained. However, the phase difference expression of the phase difference film disclosed in the present invention is high, and even a thin film can be easily adjusted to the desired phase difference. On the other hand, when the stretching ratio is too high, there may be the following problems: the phase difference becomes too high, or the film breaks, and the residual stress of the film is large, and the phase difference changes due to the shrinkage of the film in a hot and humid environment. However, the phase difference expression of the phase difference film disclosed in the present invention is high, and even if it is stretched under relatively mild conditions, it can be adjusted to the desired phase difference, so the phase difference change associated with shrinkage can be effectively suppressed. In addition, since the formability or stretchability of the phase difference film disclosed in the present invention is excellent, it has toughness even if it is formed into a thin film, so the film is not easy to break.

[0300] The stretching speed (elongation / minute) can be selected, for example, from a range of about 50 to 600% / minute, preferably 100 to 500% / minute, and more preferably 200 to 400% / minute. It should be noted that in this specification and claims, the elongation is defined as:

[0301] (Length after stretching - length before stretching) / length before stretching x 100[%].

[0302] When the stretching speed is too fast, the film may break, and when the stretching speed is too low, the desired phase difference may not be obtained.

[0303] It is to be noted that a preheat treatment may be performed before stretching and / or a heat fixation treatment may be performed after stretching. Through these treatments, the change in the phase difference after stretching can be reduced, and the change in the orientation angle (the angle between the length direction of the film and the slow axis (or orientation axis)) accompanied by bowing (a phenomenon in which the slow axis (or orientation axis) becomes uneven (bowed) in the width direction due to deformation) is reduced. Either a preheat treatment or a heat fixation treatment may be performed, but preferably both are performed. These treatments are preferably performed by clamping with a clip (or a tenter), and are particularly preferably performed continuously with the stretching process.

[0304] In the preheating treatment, the heating temperature is set to the minimum value Tg among the Tg values ​​of all the resin components contained in each layer. min When, for example, Tg min -10~Tg min +20℃ range, preferably Tg min +7~Tg min+9°C, preferably the same temperature as the stretching temperature. The preheating time can be selected, for example, from a range of about 1 second to 20 minutes, preferably 1 to 15 minutes, more preferably 5 to 12 minutes.

[0305] In the heat setting treatment, the heating temperature is set to Tg 100, which is the minimum value among the Tg values ​​of all the resin components contained in each layer. min When, for example, Tg min -5~Tg min +25℃, preferably Tg min ~Tg min +15°C. In addition, the heating temperature may be lower than the stretching temperature, for example, a temperature about 1 to 50°C lower than the stretching temperature, preferably a temperature 2 to 40°C lower than the stretching temperature, and more preferably a temperature 3 to 30°C lower than the stretching temperature. Furthermore, the heating temperature is particularly preferably lower than the stretching temperature and Tg min The heat fixation treatment time can be selected, for example, from the range of about 1 second to 10 minutes, preferably 5 seconds to 4 minutes, more preferably 10 seconds to 2 minutes. During heat fixation, the width of the tenter is preferably reduced by about 0 to 10% relative to the width after stretching.

[0306] When uniaxial stretching is performed as described above to form a quarter wave plate, when the in-plane phase difference at a wavelength of λnm is set to Ro(λ), the Ro(550) of the phase difference film can be, for example, about 100 to 170nm, preferably 110 to 160nm, 120 to 155nm, 125 to 150nm, 130 to 145nm, and 133 to 143nm in sequence.

[0307] In addition, Ro(450) / Ro(550) may be, for example, not less than 0.7 and less than about 1, and preferred ranges are 0.75 to 0.95, 0.8 to 0.9, and 0.81 to 0.87, respectively.

[0308] In the case of an ideal broadband quarter wave plate, Ro(550) is 137.5 nm and Ro(450) / Ro(550) is approximately 0.818. The closer Ro(550) and Ro(450) / Ro(550) are to the ideal values, the better the broadband quarter wave plate is. Among the characteristics of the in-plane phase difference Ro(550), the dispersion Ro(450) / Ro(550) and the thickness (thinness), it is particularly important that the in-plane phase difference Ro(550) is close to the ideal value.

[0309] In addition, in this specification and claims, Ro(550) and Ro(450) / Ro(550) can be measured by the method described in the Examples mentioned later.

[0310] (VA-LCD phase difference film)

[0311] The phase difference film (optical compensation film) for VA-LCD can be prepared by biaxial stretching. As biaxial stretching, it can be simultaneous biaxial stretching in which the longitudinal and transverse directions are stretched simultaneously, or it can be sequential biaxial stretching in which one direction is stretched one by one. In addition, it can be equiaxial (equal ratio) stretching in which the longitudinal and transverse stretching ratios are equal, or it can be eccentric stretching with different stretching ratios.

[0312] As a preferred biaxial stretching, from the viewpoint of being able to suppress the change of the slow axis in the film surface while being easy to freely adjust the stretching conditions and having excellent formability, the following can be cited: sequential biaxial stretching. In the sequential biaxial stretching, the longitudinal stretching along the length direction of the film and the transverse stretching along the width direction of the film can be stretched discontinuously (after stretching in one direction, winding up and then providing stretching in another direction), but from the viewpoint of formability (or productivity), it is preferably stretched continuously. As a specific stretching method, the above-mentioned method can be cited, and the longitudinal stretching is preferably roller-to-roll stretching or tenter stretching, and the transverse stretching is preferably tenter stretching.

[0313] The order of longitudinal stretching and transverse stretching is not particularly limited, and transverse stretching is preferably performed after longitudinal stretching, and more preferably transverse stretching is performed after longitudinal stretching under a stronger stretching condition (a stretching condition in which the molecular chains are more oriented and the phase difference is higher) than the longitudinal stretching. In such a sequential biaxial stretching, it is preferred that the film be formed in such a way that the slow axis in the film plane (the direction in which the refractive index in the film plane is the largest) is approximately perpendicular to the length direction of the film, for example, at an angle of 80 to 100°, preferably 85 to 95°.

[0314] In detail, as described above, the phase difference film for VA-LCD is arranged between the liquid crystal unit and the linear polarizer (linear polarizer) arranged above and below the liquid crystal unit, and specifically, it is stacked in a manner such that the slow axis in the film surface of the phase difference film is approximately perpendicular to the absorption axis of the linear polarizer. Generally, the linear polarizer is configured to have an absorption axis in the length direction of the film, so as described above, when the phase difference film with the slow axis approximately perpendicular to the length direction of the film is stacked, it can be laminated by a roll-to-roll method, which is advantageous in terms of formability (or productivity).

[0315] The stretching temperature may be the same or different in the longitudinal stretching and the transverse stretching. The minimum value of the Tg of all the resin components contained in each layer is set as Tg min When the stretching temperature is, for example, Tg min -10~Tg min +30℃, as the preferred range, the following are 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 min +11°C. As a specific temperature, for example, it is 117 to 157°C, and as a preferred range, the following are 127 to 147°C, 132 to 142°C, 134 to 140°C, 135 to 139°C, and 136 to 138°C. When the stretching temperature is too high, the following problems may occur: not only is it difficult to show the desired phase difference, but the film cannot be stretched uniformly, and the film thickness becomes uneven. When the stretching temperature is too low, not only is it difficult to show the desired phase difference, but the film may also break.

[0316] The stretching ratio can be the same in the longitudinal stretching and the transverse stretching, but it is preferably different, and it is more preferred that the stretching ratio of the transverse stretching is larger than that of the longitudinal stretching. The stretching ratio of the longitudinal stretching (or the stretching in the MD direction (or the length direction of the film)) can be selected, for example, from the range of about 1.1 to 10 times, and as a preferred range, the following are 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 of the transverse stretching (or the stretching in the TD direction (or the width direction of the film)) can be selected, for example, from the range of about 1.1 to 10 times, and as a preferred range, the following are 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. When the stretching ratio is too low, the desired phase difference may not be obtained. However, the phase difference performance of the phase difference film disclosed in the present invention is high, and even a thin film can be easily adjusted to the desired phase difference. On the other hand, when the stretching ratio is too high, the following problems may occur: the phase difference becomes too high, or the film breaks, and the residual stress of the film is large, and the phase difference changes due to the shrinkage of the film in a hot and humid environment. However, the phase difference performance of the phase difference film disclosed in the present invention is high, and even if it is stretched under relatively mild conditions, it can be adjusted to the desired phase difference, so the phase difference change accompanying shrinkage can be effectively suppressed. In addition, since the formability or stretchability of the phase difference film disclosed in the present invention is excellent, it has toughness even if it is formed into a thin film, so the film is not easy to break.

[0317] The stretching speed (elongation / minute) may be the same or different in the longitudinal stretching and the transverse stretching. The stretching speed (elongation / minute) of the longitudinal stretching may be selected, for example, from the range of about 50 to 600% / minute, preferably 100 to 500% / minute, and more preferably 200 to 400% / minute. The stretching speed (elongation / minute) of the transverse stretching may be selected, for example, from the range of about 50 to 600% / minute, preferably 100 to 500% / minute, and more preferably 200 to 400% / minute. When the stretching speed is too fast, the film may break. When the stretching speed is too low, the desired phase difference may not be obtained.

[0318] It is to be noted that a preheat treatment may be performed before stretching and / or a heat fixation treatment may be performed after stretching. Through these treatments, the change in the phase difference after stretching can be reduced, and the change in the orientation angle (the angle between the length direction of the film and the slow axis (or orientation axis)) accompanied by bowing (a phenomenon in which the slow axis (or orientation axis) becomes uneven (bowed) in the width direction due to deformation) is reduced. Either a preheat treatment or a heat fixation treatment may be performed, but preferably both are performed. These treatments are preferably performed by clamping with a clip (or a tenter), and are particularly preferably performed continuously with the stretching process.

[0319] In the preheating treatment, the heating temperature is set to the minimum value Tg among the Tg values ​​of all the resin components contained in each layer. min When, for example, Tg min -10~Tg min +30℃ or so, preferably Tg min +9~Tg min +11°C, more preferably the same temperature as the stretching temperature. The preheating time can be selected, for example, from a range of about 1 second to 20 minutes, preferably 1 to 15 minutes, more preferably 5 to 12 minutes.

[0320] In the heat setting treatment, the heating temperature is set to Tg 100, which is the minimum value among the Tg values ​​of all the resin components contained in each layer. min When, for example, Tg min -5~Tg min +25℃, preferably Tg min ~Tg min +15°C. In addition, the heating temperature may be lower than the stretching temperature, for example, a temperature about 1 to 50°C lower than the stretching temperature, preferably a temperature 2 to 40°C lower than the stretching temperature, and more preferably a temperature 3 to 30°C lower than the stretching temperature. Furthermore, the heating temperature is particularly preferably lower than the stretching temperature and Tg minThe heat fixation treatment time can be selected, for example, from the range of about 1 second to 10 minutes, preferably 5 seconds to 4 minutes, more preferably 10 seconds to 2 minutes. During heat fixation, the width of the tenter is preferably reduced by about 0 to 10% relative to the width after stretching.

[0321] When biaxial stretching is performed as described above to form a phase difference film for VA-LCD, when the in-plane phase difference at a wavelength of λnm is set to Ro(λ), Ro(550) of the phase difference film for VA-LCD can be, for example, about 20 to 65nm, and preferably 25 to 60nm and 30 to 55nm, respectively.

[0322] The Ro(450) / Ro(550) of the retardation film for VA-LCD may be, for example, not less than 0.7 and less than about 1, and preferred ranges are 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.

[0323] In addition, when the phase difference in the thickness direction at a wavelength of λnm is set to Rth(λ), Rth(589) can be, for example, about 100 to 160nm. The preferred ranges are 110 to 150nm, 115 to 145nm, 120 to 140nm, and 125 to 135nm, respectively.

[0324] It should be noted that in the phase difference film for VA-LCD, especially for TV (television) applications, among the characteristics of in-plane phase difference Ro(550), dispersion Ro(450) / Ro(550), phase difference in the thickness direction Rth(589) and thickness (thinness), Ro(550), Ro(450) / Ro(550) and Rth(589) are considered to be highly important characteristics, and it is particularly important to make Ro(550) and Rth(589) within the above-mentioned preferred range.

[0325] In addition, in this specification and claims, Ro(550), Ro(450) / Ro(550) and Rth(589) can be measured by the methods described in the Examples described later.

[0326] Example

[0327] Hereinafter, the present disclosure will be described in more detail based on examples, but the present disclosure is not limited to these examples. Hereinafter, the evaluation method and raw materials are described in detail.

[0328] [Evaluation method]

[0329] (Glass transition temperature Tg)

[0330] A sample was placed in an aluminum pan using a differential scanning calorimeter ("DSC 6220" manufactured by Seiko Instruments), and Tg was measured in a range of 30°C to 200°C at a heating rate of 10°C / min in a nitrogen atmosphere.

[0331] (Molecular weight)

[0332] The sample was dissolved in chloroform using a gel permeation chromatography (manufactured by Tosoh Corporation, “HLC-8120GPC”), and the weight average molecular weight Mw was measured in terms of polystyrene.

[0333] (In-plane phase difference Ro and thickness direction phase difference Rth)

[0334] Using a retardation measuring device ("RETS-100" manufactured by Otsuka Electronics Co., Ltd.), at a measuring temperature of 20°C, the in-plane phase difference Ro(450) at a wavelength of 450nm and the in-plane phase difference Ro(550) at a wavelength of 550nm of the stretched film were measured as the actual measured value of the thickness of each sample, 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 589nm of the stretched film was also measured using the same device.

[0335] (Average Thickness)

[0336] A thickness gauge ("micrometer" manufactured by Mitutoyo Co., Ltd.) was used to measure multiple points at predetermined intervals and calculate the average value. It should be noted that the average thickness of each original film (unstretched film) and each stretched film in the examples is substantially the same as the thickness near the center of the film.

[0337] [raw material]

[0338] FDPM: 9,9-bis(2-methoxycarbonylethyl)fluorene [also known as 9,9-bis(2-carboxyethyl)fluorene dimethyl ester or fluorene-9,9-dipropionate dimethyl ester] was synthesized in the same manner as in Example 1 described in JP-A-2005-89422 except that 56.6 g (0.44 mol) of tert-butyl acrylate was replaced with 37.9 g (0.44 mol) of methyl acrylate.

[0339] BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, manufactured by Osaka Gas Chemical Co., Ltd.

[0340] EG: Ethylene glycol

[0341] Polyamide resin: Y in formula (4) 1 A diamine unit in which r1 and r2 are 0 and a dicarboxylic acid unit [-OC-(CH2)10 -CO-] formed polyamide resin, "TrogamidCX7323" from Daicel Evonik, glass transition temperature Tg: 132°C

[0342] [Synthesis example 1]

[0343] 2×10 manganese acetate tetrahydrate as a transesterification catalyst was added to 1.00 mol of FDPM, 0.90 mol of BPEF, and 2.10 mol of EG. -4 8×10 moles of calcium acetate monohydrate -4 After the temperature reached 230°C, 14×10 trimethyl phosphate was added. -4 mole, germanium oxide 20×10 -4 EG was removed while the temperature was gradually raised and the pressure was reduced to 270°C and 0.13 kPa or less. After a predetermined stirring torque was reached, the contents were taken out from the reactor to prepare pellets of a fluorene ring-containing polyester.

[0344] pass 1 The obtained particles were analyzed by H-NMR. As a result, 100 mol % of the dicarboxylic acid units introduced into the fluorene ring-containing polyester were derived from FDPM, 90 mol % of the diol units introduced were derived from BPEF, and 10 mol % were derived from EG.

[0345] The obtained fluorene ring-containing polyester had a glass transition temperature Tg of 127° C. and a weight average molecular weight Mw of 60,000.

[0346] [Examples 1 to 5]

[0347] The fluorene ring-containing polyester prepared in Synthesis Example 1 was used as a surface layer and the polyamide resin was used as a core layer to prepare a two-layer three-layer multilayer film in which the surface layers were laminated on both sides of the core layer. Specifically, the fluorene ring-containing polyester and the polyamide resin were dried and then respectively put into an extruder (surface layer extruder: φ25 mm, L / D=25; core layer extruder: φ30 mm, L / D=38) equipped with a feed block T-die (die width 300 mm) and melt-extruded to the set film thickness (thickness of each layer, total thickness) of the original film recorded in Table 1, and a two-layer three-layer multilayer film (original film) having an average total thickness of 100 μm was prepared.

[0348] The obtained multilayer film was cut into a size of 60 mm × 60 mm, and a tenter-type stretching device ("IMC-1A97 Model" manufactured by Imoto Seisakusho Co., Ltd.) was used to perform fixed-end uniaxial stretching in the TD direction at the stretching temperature and stretching ratio described in Table 1, and a stretching speed of 120 mm / min (300% / min) in an effective width of 40 mm excluding the clamp (chuck) portion to prepare a stretched film. It should be noted that in the multilayer film, a preheating treatment was performed for 10 minutes at the same temperature as the stretching temperature before stretching. In addition, the thickness ratio of each layer in the obtained stretched film was the same as the thickness ratio of each layer in the original film.

[0349] Table 1 shows Ro(450), Ro(550), Ro(450) / Ro(550) of the obtained stretched film and the average thickness (total film thickness) of the stretched film.

[0350] In Table 1, the surface layer thickness of the original film indicates the total thickness of two layers, and the thickness of each surface layer is 37.5 μm.

[0351]

[0352] As can be seen from Table 1, the phase difference films obtained in Examples 1 to 5 have characteristics suitable for broadband 1 / 4 wave plates, and a film with a thickness of about 30 μm is prepared. In addition, the polyester and polyamide resins containing fluorene rings that form the phase difference films of Examples 1 to 5 have relatively high Tg and excellent heat resistance (environmental reliability). Among them, from the perspective of being close to the characteristics of an ideal broadband 1 / 4 wave plate (Ro (550) is 137.5 nm, Ro (450) / Ro (550) is 0.818) and being a thin film, Examples 1 to 4 are preferred, Examples 1, 2 and 4 are more preferred, and Examples 2 and 4 are further preferred.

[0353] [Examples 6 to 8]

[0354] Melt extrusion molding was performed to the set film thickness (thickness of each layer, total thickness) of the original film recorded in Table 2, and the average total thickness of the two three-layer film was 170 μm. Except for this, the same operation was performed as in Example 1 to prepare a two-type three-layer multilayer film (original film) having the polyester containing fluorene rings prepared in Synthesis Example 1 as the surface layer, the polyamide resin as the core layer, and the surface layers laminated on both sides of the core layer.

[0355] The obtained multilayer film was cut into a size of 60 mm × 60 mm, and a tenter-type stretching device ("IMC-1A97" manufactured by Imoto Seisakusho Co., Ltd.) was used to perform successive biaxial stretching (stretching in the MD direction and then in the TD direction) on an effective width area excluding the clamp portion at the stretching temperature and stretching ratio described in Table 2, and a stretching speed of 120 mm / min (300% / min) in each stretching direction, to prepare a stretched film. It should be noted that in the multilayer film, a preheating treatment was performed for 10 minutes at the same temperature as the stretching temperature before stretching. In addition, the thickness ratio of each layer in the obtained stretched film is the same as the thickness ratio of each layer in the original film. Ro(450), Ro(550), Ro(450) / Ro(550), Rth(589) of the obtained stretched film and the average thickness (total film thickness) of the stretched film are shown in Table 2.

[0356]

[0357] In Table 2, the surface thickness of the original film indicates the total thickness of the two layers, and the thickness of each surface layer is 65 μm. In addition, the stretching temperature is the same temperature used in the stretching in the MD direction and the TD direction, and the stretching ratio is:

[0358] The magnification in the longitudinal direction (MD direction or film length direction) × the magnification in the transverse direction (TD direction or film width direction).

[0359] As can be seen from Table 2, the phase difference films obtained in Examples 6 to 8 have properties suitable for optical compensation films for VA-LCD and can be prepared into thin films. In particular, from the viewpoint that Ro and Rth are within a more preferred range, Examples 6 and 7 are preferred.

[0360] Industrial Applicability

[0361] The phase difference performance and reverse wavelength dispersion of the phase difference film disclosed in the present invention are both excellent. Therefore, it can be made by stable stretching conditions, is thin, and has excellent mechanical strength (or operability) such as toughness, and excellent environmental resistance reliability. Therefore, it can be applied to circular polarizers with anti-reflection performance in a wide band and organic EL displays equipped with the circular polarizers, as well as phase difference films for VA-LCD and liquid crystal display devices in vertical orientation mode.

Claims

1. A phase difference film comprising: a polyester resin having negative orientation birefringence and phase difference dispersibility along the wavelength, and a polyamide resin having positive orientation birefringence and phase difference dispersibility along the wavelength, The present invention is a laminated film comprising a first layer containing the polyester resin and a second layer containing the polyamide resin and being co-stretched, The difference between the glass transition temperature of the polyester resin and the glass transition temperature of the polyamide resin is 0 to 30° C., The thickness of the retardation film is 20 to 50 μm, and when the in-plane retardation at a wavelength of λ nm is defined as Ro(λ), Ro(550) is 120 to 155 nm, and Ro(450) / Ro(550) is 0.75 to 0.

95.

2. The phase difference film according to claim 1, wherein The polyester resin includes a structural unit having a fluorene-9,9-diyl group, The polyamide-based resin includes a structural unit having an alicyclic skeleton.

3. The phase difference film according to claim 1 or 2, wherein: The polyester resin comprises at least one structural unit selected from a fluorene dicarboxylic acid unit (A1) and a fluorene diol unit (B1) as a structural unit having a fluorene-9,9-diyl group, The fluorene dicarboxylic acid unit (A1) comprises a dicarboxylic acid unit represented by the following formula (1): In the formula, R 1 represents a substituent, k represents an integer from 0 to 8, and X 1a and X 1b Each independently represents a divalent hydrocarbon group which may have a substituent, The fluorene diol unit (B1) comprises a diol unit represented by the following formula (2): In the formula, R 2 represents a substituent, m represents an integer from 0 to 8, and X 2a and X 2b Each independently represents a divalent hydrocarbon group which may have a substituent, A 1a and A 1b Each independently represents a linear or branched alkylene group, and n1 and n2 represent an integer greater than 0.

4. The phase difference film according to claim 3, wherein: The fluorene diol unit (B1) includes a diol unit represented by the following formula (2A): In the formula, Z 1a and Z 1b Each independently represents an aromatic hydrocarbon ring, R 3a and R 3b Each independently represents a substituent, p1 and p2 each independently represent an integer greater than 0, R 2 ,m,A 1a and A 1b , n1 and n2 are respectively the same as those defined in formula (2) described in claim 3.

5. The phase difference film according to claim 4, wherein: The polyester resin comprises a (poly)alkylene glycol unit (B2) represented by the following formula (3): In the formula, A 2 represents a linear or branched alkylene group, and q represents an integer of 1 or greater.

6. The phase difference film according to claim 5, wherein: Regarding the polyester resin, In the formula (1), X 1a and X 1b Straight or branched chain C 2-4 Alkylene, In the formula (2A), Z 1a and Z 1b C 6-12 Aromatic ring, R 3a and R 3b C 1-4 Alkyl or C 6-10 Aryl, p1 and p2 are integers from 0 to 2, A 1a and A 1b Straight or branched chain C 2-4 Alkylene, n1 and n2 are integers from 0 to 2, In the formula (3), A 2 Straight or branched chain C 2-4 Alkylene, q is an integer of 1 to 4.

7. The phase difference film according to claim 1 or 2, wherein: The polyamide resin comprises a diamine unit represented by the following formula (4): Where Y 1 represents a direct bond or a divalent hydrocarbon group which may have a substituent, R 4a and R 4b Each independently represents a substituent, and r1 and r2 each independently represent an integer of 0 to 4.

8. The phase difference film according to claim 7, wherein: The polyamide-based resin includes a structural unit derived from an aliphatic dicarboxylic acid component.

9. The phase difference film according to claim 8, wherein The polyamide resin comprises: In the formula (4), Y 1 C 1-4 Alkylene, R 4a and R 4b C 1-4 alkyl, a diamine unit wherein r1 and r2 are 0 or 1, and From straight or branched chain C 4-16 The constituent unit of the alkane-dicarboxylic acid component.

10. The phase difference film according to claim 1 or 2, wherein: The difference between the glass transition temperature of the polyester resin and the glass transition temperature of the polyamide resin is 0 to 20°C. 11 . The retardation film according to claim 1 or 2 , which is a laminated film with a three-layer structure in which the first layer is laminated on both surfaces of the second layer.

12. The phase difference film according to claim 1 or 2, 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.

13. The retardation film according to claim 1 or 2, which has a thickness of 20 to 45 μm. The phase difference film according to claim 1 or 2, which is a uniaxially stretched film.

15. The phase difference film according to claim 14, wherein When the in-plane phase difference at a wavelength of λ nm is defined as Ro(λ), Ro(550) is 125 to 150 nm, and Ro(450) / Ro(550) is 0.8 to 0.

95. The phase difference film according to claim 14 , which is a quarter wave plate. The phase difference film according to claim 1 or 2, which is a biaxially stretched film.

18. The phase difference film according to claim 17, wherein: When the in-plane phase difference at a wavelength of λ nm is defined as Ro(λ) and the phase difference in the thickness direction is defined as Rth(λ), Ro(450) / Ro(550) is 0.78 to 0.93 and Rth(589) is 120 to 140 nm. 19 . The phase difference film according to claim 17 , which is an optical compensation film for a vertical alignment mode liquid crystal display.

20. A polarizer comprising the phase difference film according to any one of claims 1 to 19.

21. An image display device comprising the polarizer according to claim 20.

22. The image display device according to claim 21, which is an organic EL display or a vertical alignment mode liquid crystal display.

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