TW202421701A - Composition for forming phase difference film, method for producing phase difference film, and phase difference plate - Google Patents

Abstract

The present invention provides a phase difference film forming composition, which can be used to form a film at a lower temperature than before, for example, a solvent removal step at a lower temperature below 100°C, and can suppress the generation of unevenness during film formation to form a phase difference film with excellent optical properties. The phase difference film forming composition of the present invention comprises a polymerizable liquid crystal compound having a nematic liquid crystal phase transition temperature of 100°C to 200°C, and at least two organic solvents A and B having different boiling points. When the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound is set to X (°C), the boiling point of the organic solvent A is set to Ta (°C), and the boiling point of the organic solvent B is set to Tb (°C), the following formulas (1) to (3) are satisfied: Tb-Ta≧10 (°C)   (1) Ta＜X-30 (°C)    (2) Tb＞X-70 (°C)    (3).

Description

Composition for forming phase difference film, method for producing phase difference film, and phase difference plate

The present invention relates to a phase difference film forming composition, a method for producing a phase difference film using the phase difference film forming composition, and a phase difference plate including a cured film of the phase difference film forming composition.

One of the properties required of retardation films used in various image display devices is the ability to convert polarization in the full wavelength range. For example, it is known that in display [Re(450)/Re(550)] < In the wavelength region of the inverse wavelength dispersion of 1, the polarization conversion can be performed uniformly in theory. For example, polymerizable liquid crystal compounds with so-called T-shaped or H-shaped molecular structures often exhibit reverse wavelength dispersion when polymerized and cured, and can be used as materials for forming phase difference films (e.g., Patent Document 1). [Prior art literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 2019-191504

[The problem the invention is trying to solve]

The phase difference film formed by the polymerizable liquid crystal compound can be obtained, for example, by applying a coating liquid obtained by dissolving the polymerizable liquid crystal compound in a solvent on a supporting substrate to form a coating film, and then converting the polymerizable liquid crystal compound contained in the coating film into a liquid crystal phase state and removing the solvent by distillation. Usually, the film-forming method includes a heating and drying step for removing the solvent by distillation, but in recent years, from the perspective of reducing environmental load, a lower temperature is required during film-forming.

However, according to the research of the inventors and others, it is known that, for example, in a previous phase difference film forming composition using a polymerizable liquid crystal compound with a relatively high nematic phase transition temperature exceeding 100°C, if the drying temperature is lowered when removing the solvent, the distribution of the in-plane phase difference of the phase difference film obtained is likely to deteriorate, and sometimes uneven phase difference will occur.

The purpose of the present invention is to provide a phase difference film forming composition, which can be used to form a film at a lower temperature than before, for example, a lower temperature below 100°C to remove the solvent, and can suppress the generation of unevenness during film formation to form a phase difference film with excellent optical properties. [Technical means to solve the problem]

The present invention provides the following preferred embodiments. [1] A composition for forming a phase difference film, comprising a polymerizable liquid crystal compound having a nematic liquid crystal phase transition temperature of 100°C to 200°C, and at least two organic solvents A and B having different boiling points. When the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound is set to X (°C), the boiling point of the organic solvent A is set to Ta (°C), and the boiling point of the organic solvent B is set to Tb (°C), the following formulas (1) to (3) are satisfied: Tb-Ta≧10 (°C) (1) Ta＜X-30 (°C) (2) Tb＞X-70 (°C) (3). [2] A composition for forming a phase difference film as described in [1] above, wherein the polymerizable liquid crystal compound comprises a polymerizable liquid crystal compound (I) represented by the following formula (I): [Chemical 1] [In formula (I), L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group, G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic alkyl group, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom, k and l each independently represent an integer of 0 to 3 and satisfy the relationship of 1≦k+1, E ¹ and E ² each independently represents an alkanediyl group having 1 to 17 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the -CH ₂ - contained in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-, P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom (wherein at least one of P ¹ and P ² is a polymerizable group), and Ar is a group represented by any one of formulas (Ar-1) to (Ar-5). [Chemistry 2] [In formulae (Ar-1) to (Ar-5), ﹡ represents a bonding moiety; Q ¹ represents -S-, -O- or -NR ¹¹ -, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent, Q ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; W ¹ and W ² independently represent -O-, -S-, -CO- or -NR ¹¹ -, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, Y ² represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent, the hydrogen atom contained in the alkyl group may be substituted with a halogen atom, the -CH ₂ contained in the alkyl group may be substituted with a halogen atom, - may be substituted with -O-, -CO-, -O-CO- or -CO-O-; Z ¹ , Z ² and Z ³ each independently represent a hydrogen atom or an aliphatic alkyl group or alkoxy group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms, a monovalent aromatic alkyl group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ¹² R ¹³ or -SR ¹⁴ , Z ¹ and Z ² may also be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring, and R ¹² to R ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ax and Ay may also be bonded to form a ring; ^Y3 and ^Y4 each independently represent a group selected from the following formula ( ^Y3-1 ): [Chemical 3] [In the formula (Y ³ -1), ^RY1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, the alkyl group may be substituted by one or more substituents X ³ , the substituents X ³ represent a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfanyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a hydroxyl group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or one -CH ₂ - or two or more non-adjacent -CH ₂ - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or may be a group represented by -B ³ -F ³ -P ³ (herein, B ³ represents -CR ¹⁶ R ¹⁷ -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ^{18 -, -NR 18 -CO-} , -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms; F ³ represents an alkanediyl group having 1 to 12 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted by -OR ¹⁹ or a halogen atom; R ¹⁹ represents an alkyl group having 1 to 4 carbon atoms, the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, and the -CH ₂ - contained in the alkanediyl group may be substituted by -O- or -CO-; P ³ represents a hydrogen atom or a polymerizable group), U ¹ represents an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group, any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom, and the aromatic hydrocarbon group may be substituted with one or more of the substituents X ³ mentioned above; T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU ² -, -N=CU ² -, -CO-NU ² -, -OCO-NU ² -, or O-NU ² -, U ² represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or (E ³ -A ³ ) _q -B ³ -F ³ -P ³ , the alkyl, cycloalkyl, cycloalkenyl and aromatic hydrocarbon groups may be unsubstituted or substituted with one or more substituents X ³ , the alkyl may be substituted by the cycloalkyl or cycloalkenyl group, one -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO ₂ -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, one -CH 2 in the cycloalkyl or cycloalkenyl group may be substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO 2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH- _OCO- , -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C- - or two or more non-adjacent -CH ₂ - may be independently substituted by -O-, -CO-, -COO-, -OCO- or O-CO-O-, E ³ is the same as the definition of B ³ above, A ³ represents a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent aromatic alkyl group having 6 to 20 carbon atoms, the hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted by a halogen atom, -R ²⁰ , -OR ²¹ , a cyano group or a nitro group, R ²⁰ represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms, R ²¹ represents an alkyl group having 1 to 4 carbon atoms, the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, B ³ , F ³ and P ³ are the same as the above B ³ , F ³ and P 3 respectively. ³ has the same meaning, q represents an integer of 0 to 4, and when a plurality of E ³ and/or A ³ are present, they may be the same or different, and U ¹ and U ² may be bonded to form a ring] group]. [3] The retardation film forming composition described in [1] or [2] above, wherein the Hansen solubility parameter distance calculated using the Hansen solubility parameters ( _δDA , _δPA , _δHA ) of the organic solvent A and the Hansen solubility parameters ( _δDB , _δPB , _δHB ) of the organic solvent B is 10 or less. [4] The retardation film forming composition described in [2] or [3] above, wherein the polymerizable liquid crystal compound further comprises a rod-shaped polymerizable liquid crystal compound. [5] The phase difference film forming composition described in any one of the above [1] to [4], wherein the solid content concentration is 5% by mass or more. [6] The phase difference film forming composition described in any one of the above [1] to [5], wherein the total content of the organic solvent A and the organic solvent B relative to the total mass of the solvent contained in the phase difference film forming composition is 80% by mass or more. [7] The phase difference film forming composition described in any one of the above [1] to [6], wherein the organic solvent A is an ether-based organic solvent or a ketone-based solvent. [8] The phase difference film forming composition described in any one of the above [1] to [7], which contains a leveling agent. [9] A method for producing a phase difference film, comprising: forming a coating of the phase difference film forming composition as described in any one of [1] to [8] above; drying the coating at a drying temperature Td (°C) to obtain a dry coating; and curing the dry coating to obtain a phase difference film; the drying temperature Td (°C) satisfies equations (4) and (5): Ta＜Td＜Tb (4) X－80≦Td≦X－20 (5). [10] The method for producing as described in [9] above, wherein the drying temperature Td is 70°C or higher and lower than 130°C. [11] A phase difference plate, comprising a cured film of the phase difference film forming composition as described in any one of [1] to [8] above. [Effect of the invention]

According to the present invention, a retardation film-forming composition can be provided, which can be used to form a film at a lower temperature than conventional ones, for example, a temperature lower than 100° C. in the solvent removal step, and can suppress the generation of unevenness during film formation to form a retardation film with excellent optical properties.

The following is a detailed description of the implementation of the present invention. Furthermore, the scope of the present invention is not limited to the implementation described here, and various modifications can be made within the scope of the subject matter of the present invention.

<Composition for forming phase difference film> The composition for forming phase difference film of the present invention comprises a polymerizable liquid crystal compound having a nematic liquid crystal phase transition temperature of 100°C to 200°C, and at least two organic solvents A and B having different boiling points. The composition for forming phase difference film of the present invention satisfies the following formulas (1) to (3) when the nematic phase transition temperature of the polymerizable liquid crystal compound is set to X°C, the boiling point of the organic solvent A is set to Ta°C, and the boiling point of the organic solvent B is set to Tb°C. Tb－Ta≧10(℃)   (1) Ta＜X－30(℃)    (2) Tb＞X－70(℃)    (3) Furthermore, in the present invention, the organic solvent with a lower boiling point in the solvent contained in the phase difference film forming composition is set as "organic solvent A", and the organic solvent with a higher boiling point is set as "organic solvent B". When the phase difference film forming composition contains three or more organic solvents, at least two organic solvents that satisfy all the above-mentioned formulas (1) to (3) in terms of the relationship with the nematic liquid crystal phase transition temperature X℃ of the polymerizable liquid crystal compound contained in the phase difference film forming composition must be included. In addition, when the phase difference film forming composition contains a plurality of polymerizable liquid crystal compounds, regarding the nematic liquid crystal phase transition temperature of the above polymerizable liquid crystal compounds, all polymerizable liquid crystal compounds constituting the phase difference film forming composition are mixed in the same ratio as the composition in the phase difference film forming composition, and the nematic liquid crystal phase transition temperature is measured using the mixture of the polymerizable liquid crystal compounds thus mixed.

Generally, if the drying temperature used to remove the organic solvent from the coating film of the composition (coating liquid) containing the polymerizable liquid crystal compound and the organic solvent is lowered, the volatility of the organic solvent will be slowed down, and it is easy to be affected by the air volume in the drying furnace, and it is easy to produce the appearance defects such as uneven wind-induced waviness on the coating surface. Most of the organic solvents previously used to dissolve polymerizable liquid crystal compounds with T-shaped or H-shaped molecular structures that can show reverse wavelength dispersion have a high boiling point of more than 100°C, and it is difficult to reduce the drying temperature without producing the appearance defects such as uneven wind-induced waviness during film formation. In contrast, the phase difference film forming composition of the present invention includes organic solvent A and organic solvent B that satisfy the above formulas (1) to (3) in a relationship with a polymerizable liquid crystal compound. Compared with the previous case where the same polymerizable liquid crystal compound is used, even if the drying step for removing the solvent is carried out at a lower temperature, it is possible to suppress the generation of unevenness or alignment defects on the coated surface and form a phase difference film with excellent appearance and optical properties.

Formula (1) means that the boiling point of organic solvent B is higher than the boiling point of organic solvent A by more than 10°C. By including at least two organic solvents with boiling points differing by more than 10°C, the volatility of each organic solvent is different, and it is easy to control the volatility of the solvent in the composition as a whole relative to the drying temperature. Thus, even if the drying temperature is low, it is not easily affected by the wind in the drying furnace, etc., and the generation of wind-induced unevenness can be suppressed. In addition, the organic solvent can be prevented from evaporating too quickly, and the crystallization or alignment defects of the liquid crystal compound caused by the volatility of the solvent can be suppressed. If the difference between Ta and Tb is appropriate, the time point of removing organic solvent A and organic solvent B can be controlled in the drying step, and the above-mentioned effect can be easily obtained. Therefore, the difference is preferably 20°C or more, more preferably 30°C or more, for example, 40°C or more or 50°C or more. On the other hand, if the difference between Ta and Tb is too large, it is difficult to fully remove each organic solvent within the preferred drying temperature range. Therefore, the difference between Ta and Tb is usually 150°C or less, preferably 120°C or less, more preferably 100°C or less, and further preferably 90°C or less, for example, 80°C or less. Furthermore, when the phase difference film forming composition contains three or more organic solvents, it is preferred that the difference in boiling point of at least one of the combination of two organic solvents satisfying the relationship of formula (2) and the organic solvent satisfying formula (3) is within the above range.

If, in addition to satisfying the above formula (1), the boiling point of organic solvent A satisfies formula (2) and the boiling point of organic solvent B satisfies formula (3) in relation to the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound contained in the phase difference film forming composition, a state is achieved in which a solvent (organic solvent A) having a boiling point lower than the phase transition temperature of the polymerizable liquid crystal compound by a certain degree or more and a solvent (organic solvent B) having a boiling point higher than the solvent by a certain degree or more exist in a mixed state. In this way, the solvent can be appropriately removed in the drying step during film formation, the generation of crystallization or alignment defects of the liquid crystal compound can be suppressed, and the wind-induced waviness caused by the hot air in the drying furnace can be suppressed, thereby obtaining a phase difference film with excellent appearance and optical properties.

The boiling point Ta of the organic solvent A may also be lower than the nematic liquid crystal phase transition temperature X°C of the polymerizable liquid crystal compound, for example, above 40°C, above 50°C, or above 60°C. If Ta is too low, there is a tendency that within a preferred drying temperature range, the volatility of the solvent becomes faster, and crystallization or alignment defects of the polymerizable liquid crystal compound are easily generated. On the other hand, if Ta is too high, there is a tendency that within a preferred drying temperature range, appearance defects such as uneven wind-induced waviness are easily generated. Therefore, although it varies depending on the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound, Ta is generally above 40°C, preferably above 50°C, for example, above 60°C.

The boiling point Tb of the organic solvent B is preferably such that the difference between it and the nematic liquid crystal phase transition temperature X°C of the polymerizable liquid crystal compound is smaller than the difference between Ta and X°C. It is more preferred that Tb is lower than X°C and the difference between Tb and X°C is within 60°C, and further preferably within 50°C. In addition, if Tb is too low, there is a tendency to easily generate crystallization or alignment defects of the polymerizable liquid crystal compound in the drying step. If Tb is too high, there is a tendency as follows: within the preferred drying temperature range, it is difficult to remove the solvent, and it is easy to generate appearance defects such as uneven wind-induced moire. Therefore, although Tb varies depending on the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound, it is preferably lower than the phase transition temperature X°C and within the range of X-40°C or above.

The above-mentioned effect of suppressing uneven crystallization or wind-induced waviness is particularly easy to obtain in the following situation, that is, the boiling point Ta of the organic solvent A is lower than the drying temperature (hereinafter, also recorded as "Td") for solvent removal when forming a phase difference film from the phase difference film forming composition, and the boiling point Tb of the organic solvent B is higher than the drying temperature Td. Therefore, in one embodiment of the present invention, the boiling point Ta of the organic solvent A and the boiling point Tb of the organic solvent B are preferably in a relationship with the drying temperature Td, and have a relationship satisfying formula (4): Ta＜Td＜Tb    (4) . In other words, the phase difference film forming composition of the present invention is suitable for use in a film forming step where the drying temperature for solvent removal is higher than Ta and lower than Tb.

In one embodiment of the present invention, from the viewpoint of improving optical properties such as alignment or low haze in the drying step, it is preferred that the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound in the coating film does not reach the boiling point of the organic solvent B, and more preferably does not reach the drying temperature. Here, the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound tends to decrease in the organic solvent, so the nematic liquid crystal phase transition temperature measured with the polymerizable liquid crystal compound (alone) is often higher than the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound in the coating film (including the organic solvent).

In the present invention, the drying temperature Td can be appropriately determined by considering the nematic phase transition temperature of the polymerizable liquid crystal compound used or the boiling point of the organic solvent contained in the phase difference film forming composition, etc. As the drying temperature, for example, a temperature range of about 20 to 80°C lower than the nematic phase transition temperature of the polymerizable liquid crystal compound used is assumed, specifically preferably 70 to 140°C, more preferably 80 to 130°C, for example, below 120°C, below 110°C, further below 100°C, less than 100°C, below 95°C, or below 90°C. When the retardation film forming composition of the present invention comprises at least two organic solvents having different boiling points in a manner such that the boiling points of the organic solvents and the nematic phase transition temperature of the polymerizable liquid crystal compound satisfy the above-mentioned formulas (1) to (3), and is subjected to a drying step within the above-mentioned temperature range, the following effects are particularly easily obtained in relation to the drying temperature: the organic solvent A and the organic solvent B are volatilized and removed appropriately, the crystallization or alignment defects of the liquid crystal compound are suppressed, and the wind-induced waviness caused by the hot air in the drying furnace is suppressed.

The organic solvent A can be appropriately selected by considering the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound used, the solubility of the polymerizable liquid crystal compound, the temperature conditions of the required drying step, etc. In one aspect of the present invention, the temperature range of the boiling point Ta of the organic solvent A can be, for example, below 100°C, preferably 40 to 100°C, more preferably 50 to 100°C, further preferably 60 to 90°C, and further preferably 65 to 80°C. When the organic solvent A having a boiling point within the above range is included, even when the film is formed at a relatively low drying temperature, for example, 100°C or less, preferably 95°C or less, and more preferably 90°C or less, which is preferred from the viewpoint of reducing environmental load, the effect of suppressing wind-induced unevenness generated during drying can be achieved.

The organic solvent B can be appropriately selected by considering the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound used, the solubility of the polymerizable liquid crystal compound, the temperature conditions of the required drying step, etc. In one aspect of the present invention, the temperature range of the boiling point Tb of the organic solvent B can be, for example, more than 100°C, preferably more than 100°C and less than 300°C, more preferably 120-250°C, further preferably 120-200°C, further more preferably 120-150°C. When an organic solvent B having a boiling point within the above-mentioned range is included, even in a combination with an organic solvent A having a low boiling point of, for example, below 100°C, the crystallization or alignment defects of the liquid crystal compound can be suppressed, and even when the film is formed at a relatively low drying temperature of below 100°C, preferably below 95°C, and more preferably below 90°C, which is considered to be preferable from the viewpoint of reducing the environmental load, a phase difference film with excellent appearance characteristics can be obtained.

The Hansen solubility parameter distance (hereinafter sometimes abbreviated as "HSP distance") calculated using the Hansen solubility parameters ( _δDA , _δPA , _δHA ) of organic solvent A and the Hansen solubility parameters ( _δDB , _δPB , _δHB ) of organic solvent B is preferably 10 or less. If the compatibility of the solvents is low, the solvents are partially separated during the solvent drying step, and unevenness of the network pattern (network unevenness) caused by the low compatibility of the solvents is likely to occur, which may lead to appearance defects different from the uneven wind-induced waviness caused by the influence of the wind in the drying furnace. If the HSP distance is 10 or less, the compatibility between organic solvent A and organic solvent B becomes high, and the generation of network unevenness caused by the compatibility of the solvents can be effectively suppressed. From the perspective of suppressing network unevenness, the HSP distance is preferably 9.5 or less, and more preferably 9.0 or less. The lower limit of the HSP distance is not particularly limited, and is usually 1.0 or more, and preferably 2.0 or more.

The Hansen solubility parameter is a three-dimensional representation of the solubility parameter introduced by Hildebrand, which is divided into three components: dispersion term (δD), polar term (δP), and hydrogen bond term (δH). The dispersion term (δD) represents the effect of dispersion force, the polar term (δP) represents the effect of dipole-dipole force, and the hydrogen bond term (δH) represents the effect of hydrogen bond force.

The definition and calculation of Hansen solubility parameters are described in Hansen Solubility Parameters: A Users Handbook by Charles M. Hansen (CRC Press, 2007). In addition, by using the computer software Hansen Solubility Parameters in Practice (HSPiP), even for solvents whose literature values are unknown, the Hansen solubility parameters can be easily inferred from their chemical structures. In the present invention, when determining the Hansen solubility parameters of organic solvent A and organic solvent B, the solvents registered in the database use the values of the registered Hansen solubility parameters.

For example, when the coordinates of the Hansen solubility parameters of organic solvent A are set to _δDA , _δPA, and _δHA , and the coordinates of the Hansen solubility parameters of organic solvent B are set to _δDB , _δPB , and _δHB , the HSP distance can be calculated by the following formula. HSP distance = [4( _δDA - _δDB ) ² + (δPA _- δPB ₎ ² + (δHA _{- δHB} ) ² ] ^1/2

In the present invention, organic solvent A and organic solvent B can satisfy the above formulas (1) to (3), and preferably have an HSP distance within the above range. They are appropriately selected from known organic solvents that can dissolve polymerizable liquid crystal compounds based on the phase transition temperature or assumed drying temperature of the polymerizable liquid crystal compound used. Organic solvents A and B can be exemplified by the following solvents (the values in () are boiling points): Ketone solvents such as methyl isobutyl ketone (116°C), cyclohexanone (156°C), cyclopentanone (130°C), methyl amyl ketone (151°C), isophorone (215°C), and γ-butyrolactone (GBL) (204°C); Aromatic solvents such as xylene (144°C), mesitylene (165°C), isopropylbenzene (152°C), ethylbenzene (136°C), anisole (154°C), aniline (184°C), benzaldehyde (178°C), benzyl alcohol (205°C), methyl benzoate (199°C), ethyl benzoate (213°C), propyl benzoate (230°C), butyl benzoate (250°C), nitrobenzene (211°C), tetrahydronaphthalene (207°C); Long-chain hydrocarbon solvents such as octane (125°C), nonane (151°C), decane (174°C), undecane (196°C), and dodecane (216°C); Ethylene glycol monomethyl ether (124°C), ethylene glycol monoethyl ether (135°C), ethylene glycol-n-propyl ether (151°C), ethylene glycol-isopropyl ether (141°C), ethylene glycol-n-butyl ether (171°C), diethylene glycol dimethyl ether (162°C), diethylene glycol diethyl ether (189°C), dipropylene glycol dimethyl ether (171°C), diethylene glycol monomethyl ether (194°C), diethylene glycol monoethyl ether (202°C), diethylene glycol monobutyl ether (230°C), diethylene glycol ethyl methyl ether (176°C), diethylene glycol butyl methyl ether (212°C) , propylene glycol monomethyl ether (120℃), propylene glycol dimethyl ether (97℃), dipropylene glycol monomethyl ether (188℃), dipropylene glycol dimethyl ether (171℃), tripropylene glycol dimethyl ether (215℃), triethylene glycol monomethyl ether (249℃), triethylene glycol dimethyl ether (216℃), tetraethylene glycol dimethyl ether (276℃), propylene glycol monomethyl ether acetate (146℃), ethylene glycol monomethyl ether acetate (145℃), diethylene glycol monoethyl ether acetate (217℃), diethylene glycol monobutyl ether acetate (245℃) and other glycol solvents; Ester solvents such as propyl acetate (102°C), butyl acetate (126°C), amyl acetate (142°C), ethyl lactate (155°C), methyl methoxypropionate (143°C), ethyl ethoxypropionate (170°C), isoamyl propionate (156°C), isoamyl isobutyrate (170°C), ethyl butyrate (121°C), propyl butyrate (143°C), butyl butyrate (165°C), ethylene carbonate (244°C), propylene carbonate (242°C); Amine solvents such as N,N-dimethylformamide (153°C), N,N-dimethylacetamide (165°C), N-methyl-2-pyrrolidone (202°C), γ-butyrolactam (245°C); and Halogen solvents such as monochlorobenzene (132°C) and 1,1,2,2-tetrachloroethane (147°C); Sulfur-containing solvents such as dimethyl sulfoxide (189°C) and dimethyl sulfoxide (238°C); Ether solvents such as tetrahydrofuran (66°C), 1,3-dioxacyclopentane (77°C), 2-methyltetrahydrofuran (80°C), 1,4-dioxane (101°C), cyclopentyl methyl ether (106°C), and tetrahydropyran (88°C).

As organic solvents A and B, it is more advantageous to select those with high solubility for the polymerizable liquid crystal compound used and inert to the polymerization reaction of the polymerizable liquid crystal compound. In a preferred embodiment of the present invention, organic solvent A is an ether organic solvent or a ketone organic solvent, more preferably an ether organic solvent, and more preferably a cyclic ether organic solvent. In a preferred embodiment of the present invention, organic solvent B is selected from the group consisting of free ketone organic solvents, aromatic organic solvents, halogen organic solvents, and amide organic solvents, more preferably a ketone organic solvent or a halogen organic solvent, and more preferably a ketone organic solvent. Furthermore, in a preferred embodiment of the present invention, it is preferred that the organic solvent A is an ether solvent and the organic solvent B is a ketone solvent.

The content ratio of organic solvent A and organic solvent B can be appropriately set according to the types of organic solvent A and organic solvent B used, their boiling points, assumed drying temperature or drying conditions, etc. Although it depends on the types of organic solvent A and organic solvent B, their boiling points or drying conditions, generally, the higher the ratio of organic solvent A, the better the effect of suppressing the generation of wind-induced waviness, and the higher the ratio of organic solvent B, the better the effect of suppressing the generation of crystallization or alignment defects of liquid crystal compounds. In one embodiment of the present invention, the content ratio of organic solvent A to organic solvent B (mass ratio, organic solvent A: organic solvent B) is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, further preferably 35:65 to 65:35, and particularly preferably 40:60 to 60:40.

The phase difference film forming composition of the present invention may also contain other organic solvents (hereinafter, also referred to as "other organic solvents") other than organic solvent A and organic solvent B under the condition that the effect of the present invention is not affected. When the phase difference film forming composition contains three or more organic solvents, as long as the relationship of formulas (1) to (3) is satisfied, two solvents having the relationship can be organic solvent A and organic solvent B. In the present invention, among the combinations of two organic solvents having the relationship of an organic solvent satisfying formula (2) and an organic solvent satisfying formula (3), the two combinations with the largest ratios to the total mass of all solvents contained in the phase difference film forming composition can be regarded as organic solvent A and organic solvent B, and the organic solvents other than them can be regarded as other organic solvents. In this case, organic solvent A and organic solvent B are preferably adjacent to each other in order of boiling point from low to high. Since the control of boiling points, etc. between multiple solvents is relatively complicated, the types of organic solvents contained in the phase difference film forming composition of the present invention are usually 4 or less, preferably 3 or less, and more preferably 2.

The other organic solvent is an organic solvent different from the organic solvent A and the organic solvent B used, and can be selected from known organic solvents such as the organic solvents exemplified above as the organic solvent A and the organic solvent B. As the other organic solvent, it is more advantageous to select an organic solvent that has a high solubility in the polymerizable liquid crystal compound and is inert to the polymerization reaction of the polymerizable liquid crystal compound.

From the viewpoint of fully obtaining the effect of the present invention, the total content of the organic solvent A and the organic solvent B relative to the total mass of the solvent contained in the phase difference film forming composition is preferably 80 mass % or more, more preferably 85 mass % or more, further preferably 90 mass % or more, and may also be 100 mass % (that is, the organic solvent contained in the phase difference film forming composition may also be only the organic solvent A and the organic solvent B). In other words, the content of other organic solvents relative to the total mass of the solvent contained in the phase difference film forming composition is preferably 20 mass % or less, more preferably 15 mass % or less, further preferably 10 mass % or less, and other organic solvents may be substantially absent. If the content of other organic solvents is within the above range, the solvent can be removed without unnecessary heating in the drying step, thereby reducing the amount of residual solvent and obtaining a retardation film with excellent appearance.

The phase difference film forming composition of the present invention preferably contains an organic solvent in an amount of 5% by mass or more of its solid content concentration. If the solid content concentration is 5% by mass or more, it is easy to improve the effect of suppressing the generation of wind-induced uneven waviness. From this point of view, the solid content concentration in the phase difference film forming composition of the present invention is more preferably 8% by mass or more, and further preferably 10% by mass or more. The upper limit of the solid content concentration is not particularly limited, and from the perspective of coating properties, it is usually 40% by mass or less, and preferably 30% by mass or less. In other words, the content of the organic solvent in the phase difference film forming composition of the present invention (the total amount of organic solvents A and B, and other organic solvents (including other organic solvents)) is preferably 60-95% by mass or less relative to the total mass of the phase difference film forming composition. If the content of the organic solvent is within the above range, wind-induced unevenness is less likely to occur, and the solvent can be dried and removed without unnecessary heating in the drying step, which can reduce the amount of residual solvent, thereby obtaining a phase difference film with excellent appearance and optical properties.

The phase difference film forming composition of the present invention contains a polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (x)") having a nematic liquid crystal phase transition temperature of not less than 100°C and not more than 200°C. The polymerizable liquid crystal compound (x) is a liquid crystal compound having a polymerizable group, especially a photopolymerizable group. As the polymerizable liquid crystal compound (x), a polymerizable liquid crystal compound previously known in the field of optical films can be used. The liquid crystal properties exhibited by the polymerizable liquid crystal compound (x) can be either thermotropic liquid crystal or hydrotropic liquid crystal. In terms of accurate film thickness control, thermotropic liquid crystal is preferred. The polymerizable liquid crystal compound (x) exhibits nematic liquid crystal properties as a phase order structure, thereby also having the advantage of easy orientation control.

As the polymerizable liquid crystal compound (x), compounds satisfying all of the following (I) to (IV) can be cited. (I) A compound that can form a nematic phase; (II) Having π electrons in the long axis direction (a) of the polymerizable liquid crystal compound. (III) Having π electrons in the direction intersecting the long axis direction (a) [intersecting direction (b)]. (IV) The total number of π electrons in the long axis direction (a) is N(πa), the total number of molecular weights in the long axis direction is N(Aa), and the π electron density in the long axis direction (a) of the polymerizable liquid crystal compound is defined by the following formula (i): D(πa)＝N(πa)/N(Aa)  (i) And the total number of π electrons in the cross direction (b) is N(πb), the total number of molecular weights in the cross direction (b) is N(Ab), and the π electron density in the cross direction (b) of the polymerizable liquid crystal compound is defined by the following formula (ii): D(πb)＝N(πb)/N(Ab)  (ii) Having 0≦[D(πa)/D(πb)]≦1 [i.e., the π electron density in the cross direction (b) is greater than the π electron density in the long axis direction (a)]. Furthermore, the polymerizable liquid crystal compound satisfying all of the above (I) to (IV) can be coated on an alignment film and heated to a temperature above the phase transition temperature to form a nematic phase. In the nematic phase formed by the alignment of the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is usually aligned in a manner that the long axis directions of the polymerizable liquid crystal compound are parallel to each other, and the long axis direction becomes the alignment direction of the nematic phase.

Most polymerizable liquid crystal compounds having the above-mentioned characteristics are generally liquid crystal compounds whose liquid crystal cured films obtained by homopolymerization show reverse wavelength dispersion. As polymerizable liquid crystal compounds, from the perspective of showing reverse wavelength dispersion, liquid crystals having a T-shaped or H-shaped mesogen structure with birefringence in the direction perpendicular to the long axis of the molecule are preferred. From the perspective of obtaining stronger dispersion, T-shaped liquid crystals are more preferred. As compounds satisfying the above-mentioned characteristics (I) to (IV), specifically, for example, the following formula (I) can be cited: [Chemical 4] In the phase difference film showing reverse wavelength dispersion, in terms of easily obtaining uniform polarization conversion and excellent optical properties, in the phase difference film forming composition of the present invention, the polymerizable liquid crystal compound (x) is preferably a polymerizable liquid crystal compound represented by the above formula (I) (hereinafter, also referred to as "polymerizable liquid crystal compound (I)"). These polymerizable liquid crystal compounds can be used alone or in combination of two or more.

In formula (I), L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group.

^L1 and ^L2 are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, ^-S- , ^-Ra1ORa2- , -Ra3COORa4-, ^-Ra5OCORa6- , -Ra7OC= ^OORa8- , -N=N-, ^-CRc = ^CRd- , or -C≡C-. Here, ^Ra1 to ^Ra8 are each independently a single bond, or an alkylene group ^{having 1} to 4 carbon atoms, and ^Rc and ^Rd are each a alkyl group having 1 to 4 carbon atoms or a hydrogen _atom . ^L1 and ^L2 are each independently more preferably a single bond, ^-ORa2-1- , ^-CH2- _{, -CH2CH2-} ^{, -COORa4-1-} , or ^OCORa6-1- . Here, ^Ra2-1 , ^Ra4-1 , and ^Ra6-1 each independently represent a single bond, _-CH2- , or _-CH2CH2- . ^L1 and ^L2 each independently represent a _single bond, _-O- , _-CH2CH2- , -COO- _{, -COOCH2CH2-} , or -OCO-.

^B1 and ^B2 are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 -, or -R ^a15 OC=OOR ^a16 -. Here, R ^a9 to R ^a16 are each independently a single bond, or an alkylene group having 1 to 4 carbon atoms. ^B1 and ^B2 are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 -, or OCOR ^a14-1 -. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 are each independently a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. ^B1 and ^B2 are each independently preferably _a single bond, -O-, _-CH2CH2- , _-COO- , _-COOCH2CH2- , _-OCO- , or _-OCOCH2CH2- .

^G1 and ^G2 each independently represent a divalent aromatic group or a divalent alicyclic alkyl group. The hydrogen atom contained in the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom. ^G1 and ^G2 are each independently preferably 1,4-phenylenediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, 1,4-cyclohexanediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4-phenylenediyl substituted with methyl, unsubstituted 1,4-phenylenediyl, or unsubstituted 1,4-trans-cyclohexanediyl, and particularly preferably unsubstituted 1,4-phenylenediyl or unsubstituted 1,4-trans-cyclohexanediyl. Furthermore, it is preferred that at least one of the plural ^G1 and ^G2 is a divalent alicyclic hydrocarbon group, and it is more preferred that at least one of ^G1 and ^G2 bonded to ^L1 or ^L2 is a divalent alicyclic hydrocarbon group.

k and l are independently integers between 0 and 3, and satisfy the relationship 1≦k+l. From the perspective of expressing inverse wavelength dispersion, k and l are preferably in the range of 2≦k+l≦6, preferably k+l=4, and more preferably k=2 and l=2. If k=2 and l=2, a symmetric structure is obtained, which is preferred.

^E1 and ^E2 each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the _-CH2- contained in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-. ^E1 and ^E2 each independently represent preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

^P1 and ^P2 independently represent a polymerizable group or a hydrogen atom. From the viewpoint of the film hardness of the obtained phase difference film, it is preferred that at least one of ^P1 and ^P2 is a polymerizable group, or ^P1 and ^P2 are both polymerizable groups. Examples of the polymerizable group represented by ^P1 or ^P2 include: epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloxy group, methacryloxy group, oxirane group, and cyclobutyl group. From the viewpoint of operability or ease of production, acryloxy group, methacryloxy group, vinyloxy group, oxirane group, and cyclobutyl group are preferred, and acryloxy group is more preferred.

Ar is a group represented by any one of the formulas (Ar-1) to (Ar-5). The polymerizable liquid crystal compounds represented by the formula (I) have the following common features: they have a bulky molecular structure in the direction intersecting the long axis direction, the absorption wavelength in the short axis direction becomes a long wavelength, and the phase difference generated by the aligned liquid crystal molecules tends to have reverse wavelength dispersion. [Chemistry 5]

The total number _Nπ of π electrons contained in the divalent group containing an aromatic hydrocarbon ring or an aromatic heterocyclic ring represented by Formula (Ar-1) to Formula (Ar-5) is preferably 12 or more, more preferably 16 or more, further preferably 18 or more, and particularly preferably 20 or more. Further, it is preferably less than 36, more preferably 32 or less, further preferably 30 or less, and particularly preferably 26 or less.

In formulae (Ar-1) to (Ar-5), * represents a bonding portion with ^L1 or ^L2 in formula (I).

In formula (Ar-1), ^Q1 represents -S-, -O- or ^-NR11- , and ^R11 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. In formulas (Ar-3) and (Ar-4), ^Q2 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms.

In the formula (Ar-2), ^W1 and ^W2 independently represent -O-, -S-, -CO-, or ^-NR11- , and ^R11 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

In formula (Ar-1), ^Y1 represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group which may have a substituent, or an aromatic heterocyclic group. In formula (Ar-2), ^Y2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent. Here, the hydrogen atom contained in the alkyl group may be substituted with a halogen atom, and the _-CH2- contained in the alkyl group may be substituted with -O-, -CO-, -O-CO-, or -CO-O-.

In formulae (Ar-1) to (Ar-5), Z ¹ , Z ² and Z ³ independently represent a hydrogen atom, an aliphatic alkyl group or an alkoxy group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms, a monovalent aromatic alkyl group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ¹² R ¹³ or -SR ¹⁴ , and Z ¹ and Z ² may be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring. R ¹² to R ¹⁴ independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formulae (Ar-3) and (Ar-4), Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings, and Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings. Ax and Ay may also be bonded to form a ring.

In formula (Ar-1), ^Y1 is preferably an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, and more preferably an aromatic alkyl group having 6 to 12 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms which may have a substituent. The aromatic alkyl group or the aromatic heterocyclic group which may have a substituent is preferably a polycyclic aromatic alkyl group or a polycyclic aromatic heterocyclic group which may be substituted. In the present invention, "polycyclic aromatic alkyl group" means an aromatic alkyl group having at least two aromatic rings, and examples thereof include a condensed aromatic alkyl group formed by condensing two or more aromatic rings and an aromatic alkyl group formed by bonding two or more aromatic rings. The “polycyclic aromatic heterocyclic group” means an aromatic heterocyclic group having at least one heteroaromatic ring and at least one ring selected from the group consisting of an aromatic ring and a heteroaromatic ring. Examples thereof include an aromatic heterocyclic group formed by condensing one or more aromatic heterocyclic rings with one or more rings selected from the group consisting of an aromatic ring and a heteroaromatic ring, and an aromatic heterocyclic group formed by bonding at least one heteroaromatic ring to at least one ring selected from the group consisting of an aromatic ring and a heteroaromatic ring.

Examples of the substituents that the aromatic alkyl group or aromatic heterocyclic group may have include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, a nitroso group, an alkylsulfinyl group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an N-alkylamino group having 1 to 4 carbon atoms, an N,N-dialkylamino group having 2 to 8 carbon atoms, an amine sulfonyl group, an N-alkylamine sulfonyl group having 1 to 6 carbon atoms, and an N,N-dialkylamine sulfonyl group having 2 to 12 carbon atoms.

Examples of Y ¹ include groups represented by the following formulas (Y ¹ -1) to (Y ¹ -7).

In formula (Y ¹ -1) to formula (Y ¹ -7), the * portion represents a linking portion.

In formula (Y ¹ -1) to formula (Y ¹ -7), Z ⁴ each independently represents a halogen atom or an organic group having 1 to 20 carbon atoms, for example, preferably a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a cyano group, a nitro group, a sulfonyl group, a nitrooxy group, a carboxyl group, a trifluoromethyl group, a methoxy group, a thiomethyl group, an N,N-dimethylamino group, or an N-methylamino group; more preferably a halogen atom, a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a cyano group, a nitro group, or a trifluoromethyl group; particularly preferably a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a pentyl group, or a hexyl group.

In formula (Y ¹ -1) to formula (Y ¹ -7), V ¹ and V ² independently represent -CO-, -S-, -NR ¹⁵ -, -O-, -Se- or -SO ₂ -, preferably -S-, -NR ¹⁵ - or -O-. R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formula (Y ¹ -1) to formula (Y ¹ -7), W ³ to W ⁷ each independently represent -C= or -N=.

In formula (Y ¹ -1) to formula (Y ¹ -7), it is preferred that at least one of V ¹ , V ² and W ³ to W ⁷ represents a group containing S, N or O.

In formula (Y ¹ -1) to formula (Y ¹ -7), a each independently represents an integer from 0 to 3, preferably 0 or 1. b each independently represents an integer from 0 to 2, preferably 0.

Any group represented by formula (Y ¹ -1) to formula (Y ¹ -7) is preferably any group represented by formula (Y ¹ -8) to formula (Y ¹ -13) below, and more preferably a group represented by formula (Y ¹ -8).

[Chemistry 7]

In formula (Y ¹ -8) to formula (Y ¹ -13), Z ⁴ , a, b, V ¹ , V ² and W ³ have the same meanings as Z ⁴ , a, b, V ¹ , V ² and W ³ in formula (Y ¹ -1) to formula (Y ¹ -7).

As specific examples of Y ¹ , for example, groups represented by formula (ar-1) to formula (ar-840) described in Japanese Patent Application Laid-Open No. 2019-003177 can be cited. Among them, groups represented by the following formula are preferred.

[Chemistry 8]

In one embodiment of the present invention, the group represented by the formula (Ar-1) may specifically be groups represented by the following formulae (Ar ¹ -1) to (Ar ¹ -126): wherein the * part represents a linking part with L ¹ or L ² in the formula (I).

[Chemistry 9]

[Chemistry 10]

[Chemistry 11]

[Chemistry 12]

[Chemistry 13]

[Chemistry 14]

In one embodiment of the present invention, the group represented by the formula (Ar-2) may specifically be groups represented by the following formulae (Ar ² -1) to (Ar ² -13): wherein the * part represents a linking part with L ¹ or L ² in the formula (I).

[Chemistry 15]

In one embodiment of the present invention, the group represented by the formula (Ar-3) may specifically be groups represented by the following formulae (Ar ³ -1) to (Ar ³ -23): wherein the * part represents a linking part with L ¹ or L ² in the formula (I).

[Chemistry 16]

[Chemistry 17]

The groups represented by formulae (Ar-1) to (Ar-4) may be groups described in, for example, Japanese Patent Application Publication No. 2011-207765, Japanese Patent Application Publication No. 2008-107767, or WO2014/010325, in addition to the groups specifically exemplified above.

In formula (Ar-5), Y ³ and Y ⁴ are independently selected from the following formula (Y ³ -1): [Chemical 18] The basis represented.

In formula (Y ³ -1), ^RY1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group may be substituted by one or more substituents X ³ .

The substituent X ³ represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfanyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, an alkyl group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or one -CH ₂ - or two or more non-adjacent -CH ₂ groups. - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or the group may be a group represented by -B ³ -F ³ -P ³ . B ³ represents -CR ¹⁶ R ¹⁷ -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ¹⁸ -, -NR ¹⁸ -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond, R ¹⁶ to R ¹⁸ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms; F ³ represents an alkanediyl group having 1 to 12 carbon atoms, the hydrogen atom contained in the _alkanediyl group may be substituted with -OR ¹⁹ or a halogen atom, R ¹⁹ represents an alkyl group having 1 to 4 carbon atoms, the hydrogen atom contained in the alkyl group may be substituted with a fluorine atom, the -CH contained in the alkanediyl group may be substituted with a halogen atom, _2- may be substituted by -O- or -CO-; ^P3 represents a hydrogen atom or a polymerizable group.

The substituent ^X3 is preferably a fluorine atom, a chlorine atom, _-CF3 , _-OCF3 or a cyano group. ^RY1 is preferably an unsubstituted or hydrogen atom or an alkyl group having 1 to 6 carbon atoms substituted with one or more fluorine atoms, more preferably a hydrogen atom.

In formula (Y ³ -1), U ¹ represents an organic group having 2 to 30 carbon atoms and having an aromatic alkyl group. Any carbon atom of the aromatic alkyl group may be substituted with a heteroatom, and U ¹ is an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of an aromatic alkyl ring and an aromatic heterocyclic ring. The aromatic alkyl group may also be substituted with one or more of the substituents X ³ mentioned above.

In terms of improving wavelength dispersion, ^U1 is preferably an organic group having an aromatic heterocyclic ring in which one or more carbon atoms are substituted with heteroatoms. In terms of improving wavelength dispersion and showing higher birefringence, ^U1 is more preferably an organic group having an aromatic heterocyclic ring which is a condensed ring of a five-membered ring and a six-membered ring.

Specifically, ^U1 is preferably a group represented by the following formula: In the following formula, the group has a bond with ^T1 at any position.

[Chemistry 19]

In formula (Y ³ -1), T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU 2 -, -N=CU ² -, -CO ^- NU ² -, -OCO-NU ² -, or O-NU ² -, and U ² represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or (E ³ -A ³ ) _q -B ³ -F ³ -P ³ . The alkyl group, cycloalkyl group, cycloalkenyl group, and aromatic hydrocarbon group may be unsubstituted or substituted with one or more substituents X ³ , and the alkyl group may be substituted with the cycloalkyl group or cycloalkenyl group. One -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl group may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO ₂ -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-; one -CH ₂ - or two or more non-adjacent -CH ₂ - in the cycloalkyl or cycloalkenyl group may be independently substituted with -O-, -CO-, -COO-, -OCO- or O-CO-O-. The definition of E ³ is the same as that of B ³ above. A ³ represents a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent aromatic alkyl group having 6 to 20 carbon atoms. The hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted with a halogen atom, -R ²⁰ , -OR ²¹ , a cyano group or a nitro group. R ²⁰ represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms. R ²¹ represents an alkyl group having 1 to 4 carbon atoms. The hydrogen atom contained in the alkyl group may be substituted with a fluorine atom. B ³ , F ³ and P ³ have the same meanings as those of B ³ , F ³ and P ³ above, respectively. q represents an integer of 0 to 4. When there are multiple E ³ and/or A ³ , they may be the same or different.

In terms of good birefringence and easy synthesis, ^T1 is preferably -O-, -S-, -N=CU ² - or -NU ² -, and in terms of easy improvement of wavelength dispersion and birefringence, -O-, -S- or -NU ² - is more preferred.

U ² is preferably an alkyl or alkenyl group having 1 to 20 carbon atoms, a _cycloalkyl group having ³ to 12 carbon atoms, or a cycloalkenyl group having 3 to 12 carbon atoms, which may be substituted by one or more of the above substituents X 3, and one -CH _{2 - or two or more non-adjacent -CH 2} - groups may be independently substituted by -O-, -CO-, -COO-, -OCO-, or -O-CO-O-, or is the above alkyl or alkenyl group which may be substituted by the cycloalkyl group, cycloalkenyl group, or aryl group.

In terms of birefringence and solvent solubility, U ² is more preferably a linear alkyl group having 1 to 20 carbon atoms in which the hydrogen atom may be substituted with a fluorine atom and one -CH ₂ - or two or more non-adjacent -CH ₂ - may be independently substituted with -O-, -CO-, -COO- or -OCO-.

^U1 and ^U2 may also ^be bonded to form a ring. In this case, for example, a ^cyclic group represented by ^-NU1U2 or a cyclic group represented by -N= ^CU1U2 can be mentioned.

In terms of easy availability of raw materials, good solubility and showing a higher birefringence, ^Y3 and ^Y4 are particularly preferably groups selected from the following formulas ( ^Y3' -1) to ( ^Y3'- 47).

[Chemistry 20]

[Chemistry 21]

[Chemistry 22]

From the viewpoint of improving the alignment of the polymerizable liquid crystal compound (x), facilitating industrial production and improving productivity, the group represented by the formula (Ar-5) may specifically include the following groups. The * in the following (Ar ⁵ -1) to (Ar ⁵ -20) represents a bonding portion with L ¹ or L ² in the formula (I).

[Chemistry 23]

[Chemistry 24]

[Chemistry 25]

In formulae (Ar-1) to (Ar-5), a group represented by any one of formulae (Ar-1), (Ar-2) and (Ar-5) is more preferred, and a group represented by formula (Ar-1) is further preferred. The polymerizable liquid crystal compound represented by formula (I) may be exemplified by compounds described in Japanese Patent Publication No. 2019-003177, Japanese Patent Publication No. 2019-073496, and the like.

The nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound (I) when measured alone is preferably 100°C or more and 200°C or less. The nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound (I) is preferably 110°C or more, more preferably 120°C or more, for example, 130°C or more, and further 140°C or more. In the present invention, the nematic liquid crystal phase transition temperature can be measured, for example, using a polarizing microscope with a temperature control stage, a differential scanning calorimeter (DSC), a thermogravimetric differential thermal analyzer (TG-DTA), etc.

In the present invention, the phase difference film forming composition may also contain a polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (I). Examples of polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (I) include rod-shaped polymerizable liquid crystal compounds. Here, the rod-shaped polymerizable liquid crystal compound refers to a polymerizable liquid crystal compound whose molecular structure can be regarded as a rod-shaped structure. In the present invention, it generally refers to a polymerizable liquid crystal compound whose phase difference generated by the aligned liquid crystal molecules shows positive wavelength dispersion.

In the present invention, as a polymerizable liquid crystal compound for forming a liquid crystal cured film, for example, a compound containing a group represented by the following formula (II) (hereinafter, also referred to as "polymerizable liquid crystal compound (II)") can also be used. The polymerizable liquid crystal compound (II) generally has a tendency to show positive wavelength dispersion. These polymerizable liquid crystal compounds can be used alone or in combination of two or more.

P ⁴ -B ⁴ -E ⁴ -B ⁵ -A ⁴ -B ⁶ - (II) [In formula (Y), P ⁴ represents a polymerizable group. A ⁴ represents a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. B ⁴ represents -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ²² -, -NR ²² -CO-, -CO-, -CS- or a single bond. R ²² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ^B5 and ^B6 independently represent -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O)-O-, -OC(=O)-, -OC(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O)-NR ²² -, -NR ²² -C(=O)-, -OCH ₂ -, -OCF 2 -, -CH ₂ O-, -CF ₂ O-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -H _, -C≡N or a single bond. E ⁴ represents an alkanediyl group having 1 to 12 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted by an alkoxy group having 1 to 5 carbon atoms, wherein the hydrogen atom contained in the alkoxy group may be substituted by a halogen atom. Furthermore, the -CH ₂ - constituting the alkanediyl group may be substituted by -O- or -CO-].

The number of carbon atoms in the aromatic alkyl group and the alicyclic alkyl group represented by A ⁴ is preferably in the range of 3 to 18, more preferably in the range of 5 to 12, and particularly preferably 5 or 6. The hydrogen atom contained in the divalent alicyclic alkyl group and the divalent aromatic alkyl group represented by ^{A 4} may be substituted with a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group or a nitro group, and the hydrogen atom contained in the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms may be substituted with a fluorine atom. ^{A 4} is preferably cyclohexane-1,4-diyl or 1,4-phenylene.

E ⁴ is preferably a linear alkanediyl group having 1 to 12 carbon atoms. -CH ₂ - constituting the alkanediyl group may be substituted with -O-. Specifically, there can be mentioned: a straight-chain alkanediyl group having 1 to 12 carbon atoms, such as methylene, ethylidene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane- _{1,7 -} diyl, _octane -1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl and dodecane-1,12-diyl; -CH2 _{- CH2} -O-CH2 _- CH2-, -CH2 _{- CH2} -O- _CH2 -CH2-O-CH2- _CH2- and _{-CH2 - CH2} -O- _CH2 - _CH2 -O- _CH2 -CH2-O- _CH2 - _CH2- . ^B4 is preferably -O-, -S-, -CO-O-, or -O-CO-, and -CO-O- is more preferred. ^B5 and ^B6 are each independently preferably -O-, -S-, -C(=O)-, -C(=O)-O-, -OC(=O)-, or -OC(=O)-O-, and -O- or -OC(=O)-O- is more preferred.

The polymerizable group represented by ^P4 may be any group that can be polymerized with the polymerizable liquid crystal compound (I), for example, vinyl, vinyloxy, stilbene, acryl, acryloxy, methacryl, methacryloxy, carboxyl, acetyl, hydroxyl, aminoformyl, amino, alkylamino having 1 to 4 carbon atoms, epoxy, cyclobutyl, formyl, -N=C=O or -N=C=S. In terms of high polymerization reactivity, especially photopolymerization reactivity, a free radical polymerizable group or a cationic polymerizable group is preferred. In terms of easy handling and easy preparation of liquid crystal compounds, the group represented by P4-B4- is preferably acryloxy, methacryloxy or vinyloxy.

Examples of the polymerizable liquid crystal compound (II) include compounds represented by formula (II-1), formula (II-2), formula (II-3), formula (II-4), formula (II-5) or formula (II-6). P ⁴ -B ⁴ -E ⁴ -B ⁵ -A ⁴ -B ⁶ -A ⁵ -B ⁷ -A ⁶ -B ⁸ -A ⁷ -B ⁹ -E ⁵ -B ¹⁰ -P ⁵ (II-1) P ⁴ -B ⁴ -E ⁴ -B ⁵ -A ⁴ -B ⁶ -A ⁵ -B ⁷ -A ⁶ -B ⁸ -A ⁷ -F ⁴ (II-2) P ⁴ -B ⁴ -E ⁴ -B ⁵ -A ⁴ -B ⁶ -A ⁵ -B ⁷ -A ⁶ -B ⁸ -E ⁵ -B ¹⁰ -P ⁵ (II-3) P ^{4 -B 4 -E 4} -B ⁵ -A ⁴ -B ⁶ -A ⁵ -B ⁷ -A ⁶ -B ^{8 -E 5} -B ^{10 -P 5} -B ⁷ -E ⁵ -B ¹⁰ -P ⁵ (II-5) P ⁴ -B ⁴ -E ⁴ -B ⁵ -A ⁴ -B ⁶ -A ⁵ -F ⁴ (II-6) [wherein, A ⁴ , B ⁴ to B ⁶ and P ⁴ have the same meanings as above, A ⁵ to A ⁷ each independently have the same meaning as A ⁴ , B ⁷ to B ⁹ each independently have the same meaning as B ⁵ , B ¹⁰ has the same meaning as B ⁴ , E ⁵ has the same meaning as E ⁴ , and P ⁵ has the same meaning as P ⁴ . ^F4 represents a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxyl group, a hydroxymethyl group, a formyl group, a sulfo group ( _-SO3H ), a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom. The _-CH2- group constituting the alkyl group and the alkoxy group may be substituted with -O-.

Specific examples of polymerizable liquid crystal compounds (II) include compounds having a polymerizable group among the compounds described in "3.8.6 Network structure (completely cross-linked type)" and "6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material" of Liquid Crystal Handbook (edited by Liquid Crystal Handbook Editorial Committee, Maruzen Co., Ltd., issued on October 30, 2000), and polymerizable liquid crystals described in Japanese Patent Publication No. 2010-31223, Japanese Patent Publication No. 2010-270108, Japanese Patent Publication No. 2011-6360, and Japanese Patent Publication No. 2011-207765.

The polymerizable liquid crystal compound (II) is preferably a liquid crystal compound exhibiting nematic liquid crystal properties. When the polymerizable liquid crystal compound (II) exhibits nematic liquid crystal properties, its nematic liquid crystal phase transition temperature may be above 100° C. and below 200° C. when measured alone, or may be outside the above range, for example, may be less than 100° C.

In the present invention, when the phase difference film forming composition includes a plurality of polymerizable liquid crystal compounds, the nematic liquid crystal phase transition temperature of the mixture of polymerizable liquid crystal compounds may be 100° C. to 200° C. The nematic liquid crystal phase transition temperature of the mixture is preferably 110° C. or more, more preferably 120° C. or more, for example, 130° C. or more, and further, 140° C. or more.

The content of the polymerizable liquid crystal compound (I) in the phase difference film forming composition of the present invention can be appropriately determined according to the type or combination of the polymerizable liquid crystal compounds used, and is preferably 20 to 100 parts by mass, more preferably 40 to 100 parts by mass, further preferably 50 to 100 parts by mass, and particularly preferably 55 to 100 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound contained in the phase difference film forming composition. If the content of the polymerizable liquid crystal compound (I) is within the above range, the obtained phase difference film is likely to have reverse wavelength dispersion, which is more advantageous in terms of optical properties. Furthermore, when the phase difference film forming composition contains two or more polymerizable liquid crystal compounds (I), it is preferred that the total amount of all polymerizable liquid crystal compounds (I) contained in the phase difference film forming composition is within the above content range.

The content of the polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (I) in the phase difference film forming composition of the present invention is preferably less than 50 parts by mass, more preferably less than 40 parts by mass, further preferably less than 20 parts by mass, particularly preferably less than 10 parts by mass, and may be substantially 0 parts by mass. In one aspect of the present invention, the content of the polymerizable liquid crystal compound (II) is preferably within the above range.

The total content of the polymerizable liquid crystal compound in the phase difference film forming composition is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 99 parts by mass, and further preferably 90 to 98 parts by mass relative to 100 parts by mass of the solid content of the phase difference film forming composition. If the content of the polymerizable liquid crystal compound is within the above range, it is more advantageous from the perspective of the alignment accuracy of the obtained phase difference film. Furthermore, in the case where the phase difference film forming composition contains more than two polymerizable liquid crystal compounds, it is preferred that the total amount of all liquid crystal compounds contained in the phase difference film forming composition is within the above content range. In addition, in this specification, the solid content of the phase difference film forming composition refers to all components in the phase difference film forming composition except volatile components such as organic solvents.

The phase difference film forming composition of the present invention may also contain a polymerization initiator. The polymerization initiator is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound, and is preferably a photopolymerization initiator that generates active free radicals by the action of light from the viewpoint of being independent of the phase state of the thermotropic liquid crystal.

As for the photopolymerization initiator, any known photopolymerization initiator can be used as long as it is a compound that can cause the polymerizable liquid crystal compound to start a polymerization reaction. Specifically, a photopolymerization initiator that can generate active free radicals or acids by the action of light can be exemplified, and a photopolymerization initiator that generates free radicals by the action of light is preferred. The photopolymerization initiator can be used alone or in combination of two or more.

The photopolymerization initiator may be a known photopolymerization initiator. For example, as a photopolymerization initiator for generating active free radicals, self-cleaving benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. may be used. In addition, hydrogen-absorbent benzophenone compounds, alkylphenone compounds, benzoin ether compounds, benzoyl ketone compounds, dibenzocycloheptanone compounds, anthraquinone compounds, thiophenone compounds, 9-oxythiophenone compounds may be used. The photopolymerization initiator may be a halogenated acetophenone compound, a dialkoxyacetophenone compound, a halogenated bisimidazole compound, a halogenated trioxime compound, a trioxime compound, etc. As the photopolymerization initiator for generating an acid, an iodonium salt and a coronium salt may be used. From the viewpoint of excellent reaction efficiency at low temperature, a self-cleaving type photopolymerization initiator is preferred, and an acetophenone compound, a hydroxyacetophenone compound, an α-aminoacetophenone compound, and an oxime ester compound are particularly preferred.

The content of the photopolymerization initiator can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound, and is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound contained in the phase difference film forming composition. If it is within the above range, the alignment of the polymerizable liquid crystal compound will not be disturbed, and the reaction of the polymerizable group will proceed sufficiently.

In addition, the phase difference film forming composition may also contain a leveling agent. The leveling agent refers to an additive having the following function, that is, adjusting the fluidity of the composition so that the film obtained by coating the composition is flatter, for example, organic modified polysilicone oil-based, polyacrylate-based and perfluoroalkyl-based leveling agents can be cited. Among them, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferred.

The content of the leveling agent in the phase difference film forming composition is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound, and more preferably 0.05 to 3 parts by mass. If the content of the leveling agent is within the above range, it is easy to make the polymerizable liquid crystal compound horizontally aligned, and the obtained cured film is often smoother. If the content of the leveling agent relative to the polymerizable liquid crystal compound exceeds the above range, it is often easy to produce unevenness in the obtained cured film. Furthermore, the phase difference film forming composition may also contain two or more leveling agents.

The phase difference film forming composition of the present invention may further include additives such as antioxidants, photosensitizers, and reactive additives in addition to organic solvents and polymerizable liquid crystal compounds, and polymerization initiators or leveling agents as needed. These components may be used alone or in combination of two or more. When the phase difference film forming composition includes additives, the content thereof is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass, relative to the solid content of the phase difference film forming composition.

The phase difference film forming composition can be obtained by mixing the organic solvent A and the organic solvent B with the polymerizable liquid crystal compound and, if necessary, a polymerization initiator or a leveling agent and other components at a predetermined temperature.

<Method for producing phase difference film> The phase difference film forming composition of the present invention can be used to form a film at a lower temperature than before, for example, a lower temperature below 100°C to remove the solvent. It is excellent in suppressing the generation of unevenness during film formation, and is therefore suitable as a material (composition) for forming a phase difference film with excellent optical properties.

When a phase difference film is formed using the phase difference film forming composition of the present invention, it is advantageous to adopt the following method, for example, which comprises: a step of forming a coating of the phase difference film forming composition of the present invention; a step of drying the coating at a drying temperature Td (°C) to obtain a dry coating; and a step of hardening the dry coating to obtain a phase difference film, the drying temperature Td (°C) satisfies equations (4) and (5): Ta＜Td＜Tb   (4) X－80≦Td≦X－20   (5).

Therefore, the object of the present invention is also a method for manufacturing a phase difference film, which comprises: A step of forming a coating of the phase difference film forming composition of the present invention; A step of drying the coating at a drying temperature Td (°C) to obtain a dry coating; and A step of hardening the dry coating to obtain a phase difference film, The drying temperature Td (°C) satisfies equations (4) and (5): Ta＜Td＜Tb   (4) X－80≦Td≦X－20   (5).

The coating film of the phase difference film forming composition can be formed by coating the mixed composition on a substrate or an alignment film. As the substrate, a glass substrate or a resin film substrate and other substrates known in the field can be appropriately selected and used. From the viewpoint of processability, a resin film substrate is preferred. The resin constituting the resin film substrate includes, for example: polyolefins such as polyethylene, polypropylene, and norolefin polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene ether.

Furthermore, as an alignment film, it is preferred that the film has solvent resistance such as being insoluble in organic solvents A and B by coating the phase difference film forming composition, and has heat resistance to the heat treatment in the following drying step. Examples of alignment films include friction alignment films containing alignment polymers, photoalignment films, groove alignment films having a concave-convex pattern or a plurality of grooves on the surface, and stretch films. In terms of being easy to more precisely control the alignment direction, a photoalignment film is preferred. As such an alignment film, an alignment film commonly used in the production of optical films (especially phase difference films) can be appropriately selected for use. Specifically, for example, a friction alignment film or a photoalignment film described in Japanese Patent Publication No. 2019-191504, or a photoalignment film formed by a (co)polymer comprising a structural unit having a photoreactive group and a structural unit having a polymerizable group described in Japanese Patent Publication No. 2021-196514, can be used.

Examples of methods for applying the phase difference film forming composition on a substrate include known methods such as spin coating, extrusion coating, gravure coating, die coating, rod coating, and applicator coating, and printing methods such as flexible printing.

Next, the organic solvent is dried and removed to form a dry coating. Examples of drying methods include natural drying, ventilation drying, heating drying, and reduced pressure drying. In terms of efficiently forming a phase difference film, heating drying is preferred. In terms of the excellent effect of suppressing wind-induced moire unevenness in the phase difference film forming composition of the present invention, heating drying using hot air such as a drying furnace can be preferably used. In the present invention, it is preferred to control the drying temperature Td (℃) at this time so as to satisfy equations (4) and (5) in the relationship between the boiling point Ta (℃) of the organic solvent A constituting the phase difference film forming composition, the boiling point Tb (℃) of the organic solvent B, and the nematic liquid crystal phase transition temperature X (℃) of the polymerizable liquid crystal compound. Ta＜Td＜Tb   (4) X－80≦Td≦X－20   (5)

By setting the drying temperature to be higher than Ta and lower than Tb and within a certain range from the phase transition temperature of the polymerizable liquid crystal compound, the following effects can be obtained, namely, suppressing the uneven wind-induced waviness caused by the wind in the drying furnace, or suppressing the crystallization and alignment defects of the liquid crystal compound caused by the volatility of the solvent. In this way, a retardation film with excellent appearance and optical properties can be obtained.

By heating the coating obtained from the phase difference film forming composition in the drying step, the solvent can be dried and removed from the coating, and the polymerizable liquid crystal compound can be aligned in a desired direction (e.g., horizontal direction) relative to the coating plane. In the present invention, as the drying temperature for removing the solvent contained in the phase difference film forming composition and making the polymerizable liquid crystal compound into a desired alignment state, it is preferred to use a temperature lower than the liquid crystal phase transition temperature (nematic liquid crystal phase transition temperature) of the polymerizable liquid crystal compound contained in the above-mentioned composition, for example, a temperature about 20 to 80°C lower than the phase transition temperature of the polymerizable liquid crystal compound used. By carrying out the drying step under such conditions, the volatilization and removal of organic solvent A and organic solvent B are carried out appropriately in relation to the drying temperature, and the following effects are particularly easily obtained, namely, suppressing the generation of crystallization or alignment defects of the liquid crystal compound and suppressing the uneven wind-induced waviness caused by hot air in the drying furnace.

The drying temperature Td can be appropriately determined in consideration of the polymerizable liquid crystal compound used and the material of the substrate on which the coating is formed. In one embodiment of the present invention, the drying temperature Td is preferably 70°C or higher and lower than 130°C. From the viewpoint of suppressing excessive consumption of heat energy and improving production efficiency, the drying temperature Td is preferably 120°C or lower, further preferably 110°C or lower, and particularly preferably 100°C or lower, for example, lower than 100°C, further 90°C or lower. By adopting a relatively low heating temperature, there is also the advantage of having more options for the supporting substrate for coating the phase difference film forming composition.

The drying time can be appropriately determined according to the heating temperature, the type of polymerizable liquid crystal compound contained, the type or boiling point of the organic solvent and its amount, and is usually 15 seconds to 10 minutes, preferably 0.5 to 5 minutes.

Then, in the obtained dry coating, the alignment state of the polymerizable liquid crystal compound is maintained and the polymerizable liquid crystal compound is polymerized, thereby obtaining a polymer of the polymerizable liquid crystal compound existing in the desired alignment state, that is, a liquid crystal cured film (phase difference film). As a polymerization method, photopolymerization is generally used. In photopolymerization, the light irradiated to the dry coating is appropriately selected according to the type of polymerization initiator contained in the dry coating, the type and amount of the polymerizable liquid crystal compound. Specific examples thereof include one or more lights selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays and γ rays, or active electron beams. Among them, ultraviolet light is preferred in terms of ease of controlling the progress of the polymerization reaction or the ability to use a photopolymerization device widely used in this field, and it is preferred to select the type of polymerizable liquid crystal compound or polymerization initiator contained in the phase difference film forming composition in a manner that allows photopolymerization by ultraviolet light. In addition, the polymerization temperature can be controlled by cooling the dried coating by an appropriate cooling method while irradiating the film with light during polymerization. If the polymerization of the polymerizable liquid crystal compound is carried out at a lower temperature by adopting such a cooling method, a phase difference film can be properly formed even when a substrate with relatively low heat resistance is used. In addition, the polymerization reaction can be promoted by increasing the polymerization temperature within a range that does not cause adverse conditions caused by heat during light irradiation (such as deformation of the substrate caused by heat). A patterned cured film can also be obtained by masking or developing during photopolymerization.

Examples of the light source of the active energy line include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten filament lamps, gallium lamps, excimer lamps, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

The intensity of ultraviolet irradiation is usually 10 to 3,000 mW/cm ² . The intensity of ultraviolet irradiation is preferably within the wavelength region effective for activation of photopolymerization initiators. The irradiation time is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, and further preferably 0.1 second to 1 minute. If the ultraviolet irradiation intensity is used once or multiple times, the cumulative light amount is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , and more preferably 100 to 1,000 mJ/cm ² .

The thickness of the phase difference film can be appropriately selected according to the display device to which it is applied. It is preferably 0.2 to 5 μm, and more preferably 0.2 to 3 μm. The thickness can be measured using an interference film thickness meter, a laser microscope, or a stylus film thickness meter.

The phase difference film forming composition of the present invention can form a phase difference film within a relatively low temperature range. Therefore, by using the phase difference film forming composition of the present invention, a phase difference film with excellent optical properties can be obtained by film formation at a low temperature without reducing the optical properties that the polymerizable liquid crystal compound can originally exhibit. Therefore, the present invention also relates to a phase difference plate including a phase difference film, which is a cured film of the phase difference film forming composition of the present invention, and is cured in the state of the polymerizable liquid crystal compound in the composition being aligned. The phase difference plate composed of the cured film of the above-mentioned phase difference film forming composition can fully exhibit the optical properties that the polymerizable liquid crystal compound used can originally exhibit, and becomes a phase difference plate with higher optical performance.

The liquid crystal cured film (retardation film) constituting the phase difference plate of the present invention may be composed of a homopolymer of the polymerizable liquid crystal compound (I) in an aligned state, or may be composed of a copolymer of a mixture of the polymerizable liquid crystal compound (I) and other polymerizable liquid crystal compounds such as the polymerizable liquid crystal compound (II) in an aligned state.

In one embodiment of the present invention, the phase difference film constituting the phase difference plate of the present invention is preferably a cured film of the phase difference film forming composition of the present invention and satisfies the optical properties represented by the following formulas (a), (b) and (c). Such a liquid crystal cured film is usually a cured film formed by curing a polymerizable liquid crystal compound in a state of being oriented in a horizontal direction relative to the plane of the liquid crystal cured film. Re(450)/Re(550)≦1.00  (a) 1.00≦Re(650)/Re(550)  (b) 100 nm≦Re(550)≦180 nm   (c) [Wherein, Re(λ) represents the in-plane phase difference value of the phase difference film at a wavelength of λ nm, Re=(nx(λ)－ny(λ))×d (d represents the thickness of the phase difference film, nx represents the principal refractive index of the refractive index ellipse forming the phase difference film at a wavelength of λ nm in a direction parallel to the plane of the phase difference film, ny represents the refractive index of the refractive index ellipse forming the phase difference film at a wavelength of λ nm in a direction parallel to the plane of the phase difference film and orthogonal to the above nx direction)]

When the phase difference film satisfies the formulas (a) and (b), the phase difference film exhibits the so-called reverse wavelength dispersion property, in which the in-plane phase difference value at a short wavelength is smaller than the in-plane phase difference value at a long wavelength. In terms of improving the reverse wavelength dispersion property and further improving the optical properties of the phase difference film, Re(450)/Re(550) is preferably 0.80 or more and less than 1.0, and more preferably 0.80 or more and less than 0.92. In addition, Re(650)/Re(550) is preferably 1.00 or more, and more preferably 1.01 or more.

The above-mentioned in-plane retardation value can be adjusted by the thickness d of the retardation film. The in-plane retardation value is determined by the above formula Re(λ)=(nx(λ)-ny(λ))×d, so in order to obtain the required in-plane retardation value (Re(λ): the in-plane retardation value of the retardation film at wavelength λ (nm)), the stereo refractive index and the film thickness d can be adjusted.

Furthermore, when the phase difference film satisfies formula (c), the phase difference plate including the phase difference film functions as a λ/4 plate, and when the circular polarizing plate including the phase difference plate including the phase difference film is applied to an optical display, etc., the effect of improving the front reflection hue (the effect of suppressing coloration) is excellent. The more preferable range of the in-plane phase difference value is 120 nm ≦ Re (550) ≦ 170 nm, and the further preferable range is 130 nm ≦ Re (550) ≦ 150 nm.

The phase difference plate of the present invention can be combined with a polarizing film having a polarizing function to be used as a circular polarizing plate for liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, flexible image display devices, touch panel display devices, electronic emission display devices (such as field emission display devices (FED), surface field emission display devices (SED)), electronic paper (display devices using electric ink or electrophoretic elements, plasma display devices , projection type display devices (such as grating light valve imaging system (GLV) display devices, display devices with digital micromirror devices (DMD)) and piezoelectric ceramic displays and other display devices. The phase difference plate of the present invention is particularly suitable for use in organic electroluminescent (EL) display devices and inorganic electroluminescent (EL) display devices. Such display devices (optical displays) can show good image display characteristics by using the phase difference plate of the present invention with excellent optical properties. The various components (such as polarizing films, display elements, etc.) or structures in the circular polarizer or display device can be appropriately selected and adopt known materials and technologies. [Example]

Hereinafter, the present invention will be described in more detail by way of examples. Furthermore, unless otherwise specified, "%" and "parts" in the examples refer to mass % and mass parts, respectively.

[Preparation of a composition for forming a photo-alignment film] The photo-alignment material of the following structure (weight average molecular weight: 50000, m:n=50:50) was prepared according to the method described in Japanese Patent Laid-Open No. 2021-196514. 2 parts of the photo-alignment material and 98 parts of cyclopentanone (solvent) were mixed as components, and the obtained mixture was stirred at 80°C for 1 hour to prepare a composition for forming a photo-alignment film. Photo-alignment material: [Chemical 26]

[Production of polymerizable liquid crystal compounds] Polymerizable liquid crystal compounds (A1) to (A3) having the structures shown below were prepared respectively. Polymerizable liquid crystal compound (A1) was prepared in the same manner as the method described in Japanese Patent Publication No. 2010-31223. Polymerizable liquid crystal compound (A2) was prepared in the same manner as the method described in Japanese Patent Publication No. 2019-73496. Polymerizable liquid crystal compound (A3) was prepared in the same manner as the method described in Japanese Patent Publication No. 2016-81035.

Polymerizable liquid crystal compound (A1) [Chemical 27]

Polymerizable liquid crystal compound (A2) [Chemical 28]

Polymerizable liquid crystal compound (A3) [Chemical 29]

[Determination of nematic liquid crystal phase transition temperature of polymerizable liquid crystal compounds] 1 g of each of the produced polymerizable liquid crystal compounds (A1) to (A3) was weighed into a vial tube, and 2 g of chloroform was added to dissolve them. The obtained solution was applied to a glass substrate with a PVA alignment film that had been subjected to a friction treatment and dried. The substrate was placed in a cooling and heating device ("LNP94-2" manufactured by Japan High Tech Co., Ltd.) and heated from room temperature to 180°C, and then cooled to room temperature. The temperature change was observed using a polarizing microscope (LEXT, manufactured by Olympus Co., Ltd.), and the temperature at which the nematic liquid crystal phase was formed was measured and set as the nematic liquid crystal phase transition temperature. The obtained results are shown in Table 1. Furthermore, when two or more polymerizable liquid crystal compounds are used in combination in the embodiment, the nematic liquid crystal phase transition temperature is measured by mixing all polymerizable liquid crystal compounds constituting the phase difference film forming composition in the same ratio as the composition in the phase difference film forming composition and using the mixture of polymerizable liquid crystal compounds in the same manner as when using one polymerizable liquid crystal compound.

[Table 1] Polymerizable liquid crystal compounds Nematic liquid crystal phase transition temperature [℃] (A1) 160 (A2) 139 (A3) 127

<Example 1> [Preparation of a phase difference film forming composition (1)] According to Table 2, 0.1 parts of a leveling agent "BYK-361N" (manufactured by BM Chemie) and 3 parts of "Irgacure OXE-03" (manufactured by BASF JAPAN Co., Ltd.) as a photopolymerization initiator were added to 100 parts of a polymerizable liquid crystal compound (A1). Furthermore, a mixed solvent of organic solvent A: tetrahydrofuran (Ta: 66°C)/organic solvent B: cyclopentanone (Tb: 130°C) (mass ratio 20/80) was added so that the solid content concentration became 9%. The mixture was stirred at a temperature of 50°C for 1 hour to prepare a phase difference film forming composition (1). Furthermore, the HSP distance between tetrahydrofuran and cyclopentanone was calculated according to the following method, and the result was 7.1.

[Table 2] Polymerizable liquid crystal compound (A1) [parts] BYK-361N [unit] Irgacure OXE-03 [unit] 100 0.1 3

[Calculation method of HSP distance] HSP distance is calculated by the following formula using the Hansen solubility parameters of tetrahydrofuran ( _δDA : 16.8, _δPA : 5.7, _δHA : 8.0) and the Hansen solubility parameters of cyclopentanone ( _δDB : 17.9, _δPB : 11.9, _δHB : 5.2) registered in the database. HSP distance = [4( _δDA - _δDB ) ² + (δPA _{- δPB} ) ² + (δHA _{- δHB)} ² ] ^1/2

[Preparation of phase difference film] The above-mentioned photo-alignment film-forming composition was coated on a biaxially stretched polyethylene terephthalate (PET) film (DIAFOIL, manufactured by Mitsubishi Resin Co., Ltd.) as a substrate using a rod coater. The coated film was dried in a drying oven at 120°C for 2 minutes and then cooled to room temperature to form a dry film. Thereafter, a UV irradiation device (SPOT CURE SP-9; manufactured by Ushio Co., Ltd.) was used to irradiate polarized ultraviolet light at 100 mJ/ ^cm2 (313 nm reference) to obtain a photo-alignment film. The film thickness of the photo-alignment film measured using an elliptical polarimeter M-220 manufactured by JASCO Corporation was 200 nm. The above-mentioned phase difference film forming composition (1) is applied to the obtained photo-alignment film using a rod coater to form a coating film. The coated film is heated and dried in a drying oven at 90°C for 1 minute, and then cooled to room temperature to obtain a dry film. Subsequently, a high-pressure mercury lamp ("Unicure VB-15201BY-A" manufactured by Ushio Co., Ltd.) is used to irradiate the above-mentioned dry film with ultraviolet light of an exposure amount of 500 mJ/ ^cm2 (365 nm reference) in a nitrogen atmosphere to form a phase difference film cured in a state where the polymerizable liquid crystal compound is aligned in the horizontal direction relative to the substrate surface, thereby obtaining a phase difference plate (1) comprising substrate/photo-alignment film/phase difference film. The film thickness of the retardation film measured using a laser microscope LEXT OLS4100 manufactured by Olympus Corporation is 2.0 μm.

<Evaluation of unevenness caused by wind-induced waviness> A pair of linear polarizing elements are stacked on a light-transmitting table to form orthogonal polarization. The phase difference plate obtained in the embodiment and the comparative example is placed between the linear polarizing elements set on the light-transmitting table in the above manner. At this time, the slow axis of the phase difference film is set to be substantially 45° with the absorption axis of the polarizing element when observed from the thickness direction. Thereafter, visual observation is performed to observe the degree of unevenness caused by wind-induced waviness based on the uniformity (uniformity of phase difference) in the observed image. The results are shown in Table 4. ≪Evaluation criteria≫ A: No wind-induced unevenness was observed B: Some wind-induced unevenness was observed on less than 30% of the area of the phase difference plate C: Wind-induced unevenness was observed on less than 30% of the area of the phase difference plate D: Wind-induced unevenness was observed on the entire phase difference plate E: Obvious wind-induced unevenness was observed on the entire phase difference plate

<Evaluation of alignment> The obtained phase difference plate was observed at 400 times magnification using a polarizing microscope (BX51, manufactured by Olympus Co., Ltd.). The alignment was evaluated according to the following criteria. The results are shown in Table 4. ≪Evaluation Criteria≫ A: No crystallization of liquid crystal compound or disorder of alignment B: Slight crystallization of liquid crystal compound or disorder of alignment was observed C: Obvious crystallization of liquid crystal compound or disorder of alignment was observed

<Evaluation of network unevenness> A pair of linear polarizing elements are stacked on a light-transmitting table to form orthogonal polarization. The phase difference plate obtained in the embodiment and the comparative example is placed between the linear polarizing elements set on the light-transmitting table in the above manner. At this time, the slow axis of the phase difference film is set to be substantially 45° with the absorption axis of the polarizing element when observed from the thickness direction. Thereafter, visual observation is performed to observe the degree of network unevenness based on the uniformity (uniformity of phase difference) in the observed image. The results are shown in Table 4. ≪Evaluation Criteria≫ A: No network unevenness is observed at all B: A little network unevenness is observed C: Obvious network unevenness is observed

<Wavelength dispersion measurement> After laminating an adhesive layer (containing an adhesive of acrylic polymer) and a glass substrate in order on the surface of the phase difference plate that is opposite to the photo-alignment film side in the plane perpendicular to the thickness direction, the substrate (PET film) and the photo-alignment film constituting the phase difference plate are peeled off together, and then the adhesive layer and the COP film (transferred body) subjected to the corona treatment are laminated in order on the surface of the phase difference plate. In this way, a laminate having a glass substrate, an adhesive layer, a phase difference film, an adhesive layer, and a COP film (transferred body) in order is obtained. The in-plane phase difference of the multilayer under the wavelength of 450 nm, 550 nm, and 650 nm was measured using KOBRA-WR manufactured by Oji Instruments Co., Ltd. In addition, the in-plane phase difference under the wavelength of 450 nm, 550 nm, and 650 nm was calculated using the Cauchy dispersion formula obtained from the measurement results of the in-plane phase difference under the wavelength of 448.2 nm, 498.6 nm, 548.4 nm, 587.3 nm, 628.7 nm, and 748.6 nm. For the measured Re(450)/Re(550) values [Re(450) represents the in-plane phase difference value under light with a wavelength of 450 nm, and Re(550) represents the in-plane phase difference value under light with a wavelength of 550 nm], values of 0.80 or more but less than 0.92 were evaluated as A, values of 0.92 or more but less than 1.0 were evaluated as B, and values of 1.0 or more were evaluated as C. The results are shown in Table 4.

<Examples 2 and 3> The mixing ratio of organic solvent A and organic solvent B was changed according to the description in Table 4. The phase difference film forming composition (2), (3) and phase difference plates (2), (3) were obtained in the same manner as in Example 1. The obtained phase difference plates were evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Example 4> According to the description in Table 4, the mixing ratio of organic solvent A and organic solvent B was changed to 40/60 (mass ratio), and the solid content concentration was set to 5%. In addition, a phase difference film forming composition (4) and a phase difference plate (4) were obtained in the same manner as in Example 1. The obtained phase difference plate was evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Example 5> According to the description in Table 4, the mixing ratio of organic solvent A and organic solvent B was changed to 40/60 (mass ratio), and the solid content concentration was set to 12%. In addition, a phase difference film forming composition (5) and a phase difference plate (5) were obtained in the same manner as in Example 1. The obtained phase difference plate was evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Examples 6 to 9> A mixed solvent including organic solvent A: tetrahydrofuran/organic solvent B; cyclopentanone/other organic solvent: N-methyl-2-pyrrolidone (NMP, boiling point: 202°C) in the mixing ratio described in Table 4 was used as a solvent, and the solid content concentration was set to 12%. In addition, phase difference film forming compositions (6) to (9) and phase difference plates (6) to (9) were obtained in the same manner as in Example 1. The obtained phase difference plates were evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Examples 10 to 12> According to the description in Table 4, the mixing ratio of organic solvent A and organic solvent B was changed, and the solid content concentration was set to 12%. In addition, the phase difference film forming composition (10) to (12) and the phase difference plate (10) to (12) were obtained in the same manner as in Example 1. The obtained phase difference plate was evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Examples 13 to 18> According to the description in Table 4, the type and mixing ratio of the organic solvent were changed, and the solid content concentration was set to 12%. In addition, the phase difference film forming composition (13) to (18) and the phase difference plate (13) to (18) were obtained in the same manner as in Example 1. The obtained phase difference plate was evaluated in the same manner as in Example 1. The results are shown in Table 4. In addition, the boiling point of the solvent used is as follows. 2-Methyltetrahydrofuran: 80℃ 1,3-Dioxolane: 77℃ Monochlorobenzene: 132℃ Anisole: 154℃ Dimethyl sulfoxide (DMSO): 189℃ In addition, the HSP distance of organic solvent A and organic solvent B in each embodiment was calculated. The calculation results are shown in Table 4.

<Examples 19 and 20> A polymerizable liquid crystal compound (A2) and a polymerizable liquid crystal compound (A3) were used as polymerizable liquid crystal compounds, respectively. Phase difference film forming compositions (19), (20) and phase difference plates (19), (20) were obtained in the same manner as in Example 5. The obtained phase difference plates were evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Examples 21 to 24> The liquid crystal compound LC242 (BASF, registered trademark) represented by the following formula (LC242) was used as a polymerizable liquid crystal compound. The nematic liquid crystal phase transition temperature of LC242 is 63°C.

The polymerizable liquid crystal compound (A1) and the polymerizable liquid crystal compound (LC242) were mixed and used in the mass ratio described in Table 3. Phase difference film forming compositions (21) to (24) and phase difference plates (21) to (24) were obtained in the same manner as in Example 5. The phase difference plates obtained were evaluated in the same manner as in Example 1. The nematic liquid crystal phase transition temperature of the mixture of polymerizable liquid crystal compounds is as described in Table 4.

[table 3] Polymerizable liquid crystal compound (A1) [parts] Polymerizable liquid crystal compound (LC242) [parts] BYK-361N [unit] Irgacure OXE-03 [unit] Embodiment 21 80 20 0.1 3 Embodiment 22 60 40 0.1 3 Embodiment 23 40 60 0.1 3 Embodiment 24 20 80 0.1 3

<Reference Example> LC242 was used as a polymerizable liquid crystal compound, tetrahydrofuran was used as the solvent, the solid content concentration was set to 12%, and the drying temperature was set to 70°C. A phase difference film forming composition (25) and a phase difference plate (25) were obtained in the same manner as in Example 1. The obtained phase difference film was evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Comparative Example 1> A phase difference film forming composition (26) and a phase difference plate (26) were obtained in the same manner as in Example 1 except that only NMP was used as the solvent, the solid content concentration was set to 12%, and the drying temperature was set to 120°C. The phase difference film obtained was evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Comparative Examples 2 to 5> Except that the type of solvent and the solid content concentration were changed according to the description in Table 4, the phase difference film forming composition (27) to (30) and the phase difference plate (27) to (30) were obtained in the same manner as in Example 1. The obtained phase difference film was evaluated in the same manner as in Example 1. The results are shown in Table 4.

[Table 4] Polymerizable liquid crystal compound [parts] Nematic liquid crystal phase transition temperature X [℃] X-30 X-70 Organic solvent A Organic solvent B Organic solvent C Ta [℃] Tb [℃] Tb－Ta [℃] Tc [℃] Td [℃] Solvent ratio A/B/C HSP distance of solvent A/B Solid content concentration [%] Wind-generated uneven waves Orientation Uneven mesh Wavelength dispersion Embodiment 1 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 20/80/0 7.1 9 C A A A Embodiment 2 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 30/70/0 7.1 9 C A A A Embodiment 3 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 9 B A A A Embodiment 4 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 5 C A A A Embodiment 5 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A A Embodiment 6 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone NMP 66 130 64 202 90 40/50/10 7.1 12 A A A A Embodiment 7 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone NMP 66 130 64 202 90 50/40/10 7.1 12 A A A A Embodiment 8 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone NMP 66 130 64 202 90 35/55/10 7.1 12 A A A A Embodiment 9 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone NMP 66 130 64 202 90 40/55/5 7.1 12 A A A A Embodiment 10 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 60/40/0 7.1 12 A A A A Embodiment 11 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 70/30/0 7.1 12 A B A A Embodiment 12 (A1)100 160 130 90 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 80/20/0 7.1 12 A B A A Embodiment 13 (A1)100 160 130 90 2-Methyltetrahydrofuran Cyclopentanone - 80 130 50 - 90 40/60/0 7.2 12 A A A A Embodiment 14 (A1)100 160 130 90 1,3-Dioxacyclopentane Cyclopentanone - 77 130 53 - 90 40/60/0 6.7 12 A A A A Embodiment 15 (A1)100 160 130 90 Tetrahydrofuran Monochlorobenzene - 66 132 66 - 90 40/60/0 7.6 12 A A A A Embodiment 16 (A1)100 160 130 90 Tetrahydrofuran Anisole - 66 154 88 - 90 40/60/0 2.6 12 B A A A Embodiment 17 (A1)100 160 130 90 Tetrahydrofuran NMP - 66 202 136 - 90 40/60/0 7.1 12 C A A A Embodiment 18 (A1)100 160 130 90 Tetrahydrofuran Dimethyl sulfoxide - 66 189 123 - 90 40/60/0 11.4 12 C A C A Embodiment 19 (A2)100 139 109 69 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A A Embodiment 20 (A3)100 127 97 57 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A A Embodiment 21 (A1)80 (LC242)20 138 108 68 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A A Embodiment 22 (A1)60 (LC242)40 129 99 59 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A A Embodiment 23 (A1)40 (LC242)60 118 88 48 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A B Embodiment 24 (A1)20 (LC242)80 105 75 35 Tetrahydrofuran Cyclopentanone - 66 130 64 - 90 40/60/0 7.1 12 A A A C Reference example (LC242)10 0 63 33 -7 Tetrahydrofuran - - 66 - - 70 100/0/0 - 12 A A A C Comparison Example 1 (A1)100 160 130 90 NMP - - 202 - - 120 100/0/0 - 12 D A A A Comparison Example 2 (A1)100 160 130 90 NMP - - 202 - - 90 100/0/0 - 12 E A A A Comparison Example 3 (A1)100 160 130 90 Cyclopentanone - - 130 - - 90 100/0/0 - 12 E A A A Comparison Example 4 (A1)100 160 130 90 Cyclopentanone NMP - 130 202 72 - 90 60/40/0 2.1 12 E A A A Comparison Example 5 (A1)100 160 130 90 Tetrahydrofuran - - 66 - - 90 100/0/0 - 12 A C A A

Claims (11)

A composition for forming a phase difference film, comprising a polymerizable liquid crystal compound having a nematic liquid crystal phase transition temperature of 100°C to 200°C, and at least two organic solvents A and B having different boiling points. When the nematic liquid crystal phase transition temperature of the polymerizable liquid crystal compound is set to X (°C), the boiling point of the organic solvent A is set to Ta (°C), and the boiling point of the organic solvent B is set to Tb (°C), the following formulas (1) to (3) are satisfied: Tb-Ta≧10 (°C)   (1) Ta＜X-30 (°C)    (2) Tb＞X-70 (°C)    (3). The phase difference film forming composition of claim 1, wherein the polymerizable liquid crystal compound comprises a polymerizable liquid crystal compound (I) represented by the following formula (I): [In formula (I), L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group, G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic alkyl group, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic alkyl group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom, k and l each independently represent an integer of 0 to 3 and satisfy the relationship of 1≦k+1, E ¹ and E ² each independently represents an alkanediyl group having 1 to 17 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the _-CH2- contained in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-, ^P1 and ^P2 each independently represent a polymerizable group or a hydrogen atom (wherein at least one of ^P1 and ^P2 is a polymerizable group), Ar is a group represented by any one of the formulae (Ar-1) to (Ar-5), [Chem. 2] [In formulae (Ar-1) to (Ar-5), ﹡ represents a bonding moiety; Q ¹ represents -S-, -O- or -NR ¹¹ -, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent, Q ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; W ¹ and W ² independently represent -O-, -S-, -CO- or -NR ¹¹ -, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, Y ² represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent, the hydrogen atom contained in the alkyl group may be substituted with a halogen atom, the -CH ₂ contained in the alkyl group may be substituted with a halogen atom, - may be substituted with -O-, -CO-, -O-CO- or -CO-O-; Z ¹ , Z ² and Z ³ each independently represent a hydrogen atom or an aliphatic alkyl group or alkoxy group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms, a monovalent aromatic alkyl group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ¹² R ¹³ or -SR ¹⁴ , Z ¹ and Z ² may also be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring, and R ¹² to R ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ax and Ay may also be bonded to form a ring; ^Y3 and ^Y4 each independently represent a group selected from the following formula ( ^Y3-1 ): [Chemical 3] [In the formula (Y ³ -1), ^RY1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, the alkyl group may be substituted by one or more substituents X ³ , the substituents X ³ represent a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfanyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a hydroxyl group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or one -CH ₂ - or two or more non-adjacent -CH ₂ - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or may be a group represented by -B ³ -F ³ -P ³ (herein, B ³ represents -CR ¹⁶ R ¹⁷ -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ^{18 -, -NR 18 -CO-} , -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms; F ³ represents an alkanediyl group having 1 to 12 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted by -OR ¹⁹ or a halogen atom; R ¹⁹ represents an alkyl group having 1 to 4 carbon atoms, the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, and the -CH ₂ - contained in the alkanediyl group may be substituted by -O- or -CO-; P ³ represents a hydrogen atom or a polymerizable group), U ¹ represents an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group, any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom, and the aromatic hydrocarbon group may be substituted with one or more of the substituents X ³ mentioned above; T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU ² -, -N=CU ² -, -CO-NU ² -, -OCO-NU ² -, or O-NU ² -, U ² represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or (E ³ -A ³ ) _q -B ³ -F ³ -P ³ , the alkyl, cycloalkyl, cycloalkenyl and aromatic hydrocarbon groups may be unsubstituted or substituted with one or more substituents X ³ , the alkyl may be substituted by the cycloalkyl or cycloalkenyl group, one -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO ₂ -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, one -CH 2 in the cycloalkyl or cycloalkenyl group may be substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO 2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH- _OCO- , -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C- - or two or more non-adjacent -CH ₂ - may be independently substituted by -O-, -CO-, -COO-, -OCO- or O-CO-O-, E ³ is the same as the definition of B ³ above, A ³ represents a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent aromatic alkyl group having 6 to 20 carbon atoms, the hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted by a halogen atom, -R ²⁰ , -OR ²¹ , a cyano group or a nitro group, R ²⁰ represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms, R ²¹ represents an alkyl group having 1 to 4 carbon atoms, the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, B ³ , F ³ and P ³ are the same as the above B ³ , F ³ and P 3 respectively. ³ has the same meaning, q represents an integer from 0 to 4. When there are multiple E ³ and/or A ³ , they may be the same or different. U ¹ and U ² may also be bonded to form a ring] base]. In the retardation film forming composition of claim 1, a Hansen solubility parameter distance calculated using Hansen solubility parameters ( _δDA , _δPA , _δHA ) of the organic solvent A and Hansen solubility parameters ( _δDB , _δPB , _δHB ) of the organic solvent B is 10 or less. In the phase difference film forming composition of claim 2, the polymerizable liquid crystal compound further comprises a rod-shaped polymerizable liquid crystal compound. The phase difference film forming composition of claim 1 has a solid content concentration of 5 mass % or more. In the retardation film forming composition of claim 1, the total content of the organic solvent A and the organic solvent B is 80 mass % or more relative to the total mass of the solvents contained in the retardation film forming composition. In the phase difference film forming composition of claim 1, the organic solvent A is an ether organic solvent or a ketone organic solvent. The phase difference film forming composition of claim 1 further comprises a leveling agent. A method for manufacturing a phase difference film, comprising: forming a coating of a phase difference film forming composition as in any one of claims 1 to 8; drying the coating at a drying temperature Td (°C) to obtain a dry coating; and curing the dry coating to obtain a phase difference film; the drying temperature Td (°C) satisfies equations (4) and (5): Ta＜Td＜Tb   (4) X－80≦Td≦X－20   (5). A manufacturing method as claimed in claim 9, wherein the drying temperature Td is above 70°C and below 130°C. A retardation plate comprising a cured film of the retardation film-forming composition according to any one of claims 1 to 8.