TWI813671B - Optically anisotropic film and manufacturing method thereof - Google Patents

Abstract

The present invention is an optically anisotropic film, which contains an organic solvent with a boiling point of 120°C or above and a polymer aligned with a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or above, and an organic solvent with a boiling point of 120°C or above. The content of the solvent is 100 to 2000 ppm relative to the mass of the optically anisotropic film.

Description

Optically anisotropic film and manufacturing method thereof

The present invention relates to an optically anisotropic film composed of a polymer aligned with an organic solvent with a boiling point of 120°C or higher and a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher and a manufacturing method thereof, including the optically anisotropic film. The elliptical polarizing plate of the plastic film and the polarizing film, and the display device including the elliptical polarizing plate.

Optical anisotropic films such as retardation films are used for flat panel displays (FPDs). In recent years, from the viewpoint of thinning, optically anisotropic films obtained by curing a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and an organic solvent have been known (for example, Japanese Patent Laid-Open No. 2017-027057). .

[Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2017-027057

However, according to the research of the present inventors, it is found that such an optically anisotropic film has The remaining amount of the agent is relatively large and it does not have sufficient heat resistance. Therefore, if it is exposed to high temperature, the phase difference may change greatly. On the other hand, it was found that if drying is strengthened during the production process of the optically anisotropic film in order to reduce the amount of solvent remaining in the film, the polymerizable liquid crystal compound crystallizes before it is fully aligned in a liquid crystal state, resulting in optical anisotropy. The haze of the film increases, and as a result, when the optically anisotropic film is applied to a display device, problems such as the screen appearing white may occur.

In addition, it can be seen that a hot air drying oven is generally used as a dryer when manufacturing optically anisotropic films. However, the maximum drying temperature in a hot air drying oven is usually about 130~140°C. Therefore, if the liquid crystal phase transition temperature exceeds this temperature, polymerization For liquid crystal compounds, sufficient alignment properties cannot usually be obtained.

Therefore, the object of the present invention is to provide an optically anisotropic film that has excellent heat resistance, exhibits sufficient alignment, low haze and other excellent optical properties, and a manufacturing method thereof, including the optically anisotropic film and a polarizing film. An elliptical polarizing plate, and a display device including the elliptical polarizing plate.

The present inventors conducted intensive research to solve the above-mentioned problems, and as a result, they discovered the optical anisotropy of a polymer aligned with an organic solvent with a boiling point of 120°C or higher and a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher. If the content of the organic solvent having a boiling point of 120° C. or higher in the membrane is 100 to 2000 ppm, the above problems can be solved, leading to the completion of the present invention. That is, the present invention includes the following contents.

[1] An optically anisotropic film containing a polymer aligned with an organic solvent with a boiling point of 120°C or higher and a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher, and an organic solvent with a boiling point of 120°C or higher The content of the solvent is 100 to 2000 ppm relative to the mass of the optically anisotropic film.

[2] The optically anisotropic film described in [1], which has a haze of 2% or less.

[3] An elliptically polarizing plate including the optically anisotropic film and polarizing film described in [1] or [2].

[4] A display device including the elliptically polarizing plate described in [3].

[5] A method for manufacturing an optically anisotropic film as described in [1] or [2], which includes the following steps: adding an organic solvent with a boiling point of 120°C or higher and a liquid crystal phase transition temperature of 120°C The polymerizable liquid crystal composition of the polymerizable liquid crystal compound above ℃ is coated on the substrate or alignment film to obtain a coating layer; on the other hand, the obtained coating layer is dried at a drying temperature that does not reach the boiling point of the organic solvent and While removing the organic solvent from the coating layer, the polymerizable liquid crystal compound is aligned in a liquid crystal state; and by polymerizing the aligned polymerizable liquid crystal compound, the polymerizable liquid crystal layer is hardened to obtain an optically anisotropic film.

The optically anisotropic film of the present invention has excellent heat resistance, exhibits sufficient alignment, and has excellent optical properties such as low haze.

[Optical anisotropic film]

The optically anisotropic film of the present invention contains an organic solvent with a boiling point of 120°C or higher and a polymer aligned with a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher. The optically anisotropic film is formed by hardening a polymerizable liquid crystal composition containing an organic solvent with a boiling point of 120°C or higher and a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher, and the polymerizable liquid crystal compound is a liquid crystal. State-aligned polymerized films. In addition, in this specification, a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher may be simply referred to as a polymerizable liquid crystal compound.

<Polymerizable liquid crystal compounds and organic solvents>

The polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention is a liquid crystal compound having a polymerizable group, especially a photopolymerizable group. As the polymerizable liquid crystal compound, an optical film can be used A polymerizable liquid crystal compound previously known in the field. Photopolymerizable groups refer to groups that can participate in the polymerization reaction through reactive species generated from the photopolymerization initiator, such as active free radicals or acids. Examples of the photopolymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, and oxirane. , oxetanyl, etc. Among them, an acryloxy group, a methacryloxy group, an vinyloxy group, an oxirane group and an oxetanyl group are preferred, and an acryloxy group is more preferred. The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a liquid crystal. However, in terms of achieving dense film thickness control, a thermotropic liquid crystal is preferred. In addition, the phase order structure in the thermotropic liquid crystal may be a nematic liquid crystal or a smectic liquid crystal. In particular, from the viewpoint of easy alignment control and low haze, the polymerizable liquid crystal compound preferably exhibits nematic liquid crystallinity.

Examples of polymerizable liquid crystal compounds include compounds satisfying all of the following (1) to (4).

(1) Compounds that can form a nematic phase.

(2) The polymerizable liquid crystal compound has π electrons in the long axis direction (a).

(3) It has π electrons in the direction crossing the long axis direction (a) (crossing direction (b)).

(4) Let the total number of π electrons present in the long axis direction (a) be N(πa), and let the total number of molecular weights present in the long axis direction be N(Aa). It is defined by the following formula (i) The π electron density of the polymerizable liquid crystal compound in the long axis direction (a): D(πa)=N(πa)/N(Aa) (i) and the total number of π electrons present in the cross direction (b) are set to N(πb), let the total number of molecular weights existing in the cross direction (b) be N(Ab), the π electron density in the cross direction (b) of the polymerizable liquid crystal compound defined by the following formula (ii): D (πb)=N(πb)/N(Ab) (ii)

There is a relationship of 0≦[D(πa)/D(πb)]≦1 [that is, the π electron density in the cross direction (b) is greater than the π electron density in the longer axis direction (a)].

Furthermore, the polymerizable liquid crystal compound that satisfies all of the above (1) to (4) can form a nematic phase by being coated on, for example, an alignment film and heated to a temperature above the phase transition temperature. In the nematic phase formed by aligning the polymerizable liquid crystal compounds, the polymerizable liquid crystal compounds are usually aligned so that their long axis directions are parallel to each other, and the long axis directions become the alignment direction of the nematic phase.

Polymerizable liquid crystal compounds having the above characteristics generally exhibit reverse wavelength dispersion in many cases. Specific examples of compounds that satisfy the characteristics (1) to (4) described above include compounds represented by the following formula (I).

In formula (I), Ar represents a divalent aromatic group which may have a substituent. The aromatic group described here is a group having a planar ring structure, and refers to one in which the number of π electrons in the ring structure is [4n+2] according to Huckel's rule. Among them, n represents an integer. When heteroatoms such as -N= or -S- are included to form a ring structure, it also includes cases where the non-covalent bond electron pairs on these heteroatoms satisfy Huckel's rule and are aromatic. It is preferable that the divalent aromatic group contains at least one kind of a nitrogen atom, an oxygen atom, and a sulfur atom.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Wherein, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted by a halogen atom, an alkyl group with 1 to 4 carbon atoms, a fluoroalkyl group with 1 to 4 carbon atoms, or a fluoroalkyl group with 1 to 4 carbon atoms. The alkoxy group, cyano group or nitro group of ~4 can also replace the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group with oxygen atoms, sulfur atoms or nitrogen atoms.

L ¹ , L ² _, B ¹ and B ² are each independently a single bond or a divalent linking group.

k and l independently represent integers from 0 to 3, and satisfy the relationship of 1≦k+l. Among them, in the case of 2≦k+l, B ¹ and B ² and G ¹ and G ² may be the same as each other or different.

E ¹ and E ² respectively independently represent an alkanediyl group having 1 to 17 carbon atoms, in which the hydrogen atoms contained in the alkanediyl group may be substituted by halogen atoms, and the -CH ₂ - contained in the alkanediyl group may be substituted by - O-, -S-, -Si- substitution.

P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

G ¹ and G ² are each preferably independently a 1,4-phenylenediyl group which may be substituted by a halogen atom and at least one substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms. 1,4-cyclohexanediyl substituted by a halogen atom and at least one substituent selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, more preferably 1,4-cyclohexanediyl substituted by a methyl group Phenyldiyl, unsubstituted 1,4-phenylenediyl, or unsubstituted 1,4-trans-cyclohexanediyl, especially unsubstituted 1,4-phenylenediyl base diyl, or unsubstituted 1,4-trans-cyclohexanediyl.

Furthermore, at least one of G ¹ and G ² present in plural numbers is preferably a divalent alicyclic hydrocarbon group ^, and at least one of G ¹ and G 2 bonded to L ¹ or L ² is more preferably Bivalent alicyclic hydrocarbon group.

L ¹ and L ² are preferably each independently a single bond, an alkylene group with 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -, or C≡C-. Among them, R ^a1 to R ^a8 each independently represent a single bond or an alkyl group with 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group with 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 -, or -OCOR ^a6-1 -. Among them, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. L ¹ and L ² are each independently preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

B ¹ and B ² are preferably each independently a single bond, an alkylene group with 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 -. Among them, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 -, or OCOR ^a14-1 -. Among them, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. B ¹ and B ² are each independently preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO-, or -OCOCH ₂ CH ₂ -.

From the viewpoint of exhibiting reverse wavelength dispersion, k and l are preferably in the range of 2≦k+l≦6, k+l=4 is preferable, and k=2 and l=2 are more preferable. If k=2 and l=2, it becomes a symmetrical structure, so it is better.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by P ¹ or P ² include: epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloxy group, Methacryloxy group, ethylene oxide group, and oxetanyl group, etc. Among them, an acryloxy group, a methacryloxy group, an vinyloxy group, an oxirane group and an oxetanyl group are preferred, and an acryloxy group is more preferred.

環、嘧啶環、三唑環、三

環、吡咯啉環、咪唑環、吡唑環、噻唑環、苯并噻唑環、噻吩并噻唑環、

唑環、苯并

唑環、及啡啉環等。其中，較佳為具有噻唑環、苯并噻唑環、或苯并呋喃環，進而較佳為具有苯并噻唑基。又，於Ar中包含氮原子之情形時，該氮原子較佳為具有π電 子。 Ar preferably has at least one selected from the group consisting of an aromatic hydrocarbon ring that may have a substituent, an aromatic heterocyclic ring that may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, and a benzene ring and a naphthalene ring are preferred. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, and a pyridine ring.

ring, pyrimidine ring, triazole ring, tri

ring, pyrroline ring, imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring,

Azole ring, benzo

Azole ring, and phenanthroline ring, etc. Among them, those having a thiazole ring, a benzothiazole ring, or a benzofuran ring are preferred, and those having a benzothiazolyl group are more preferred. Moreover, when Ar contains a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

In formula (I), the total number N _π of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, further preferably 14 or more, especially The best number is 16 or more. Furthermore, the number is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

Examples of the aromatic group represented by Ar include the following groups.

[Chemicalization 2]

In the formula (Ar-1) to the formula (Ar-23), the * symbol represents a connecting part, and Z ⁰ , Z ¹ and Z ² independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, Nitro group, alkylsulfenyl group with 1 to 12 carbon atoms, alkylsulfenyl group with 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 12 carbon atoms, alkoxy group with 1 to 6 carbon atoms, Alkylthio group with 1 to 12 carbon atoms, N-alkylamino group with 1 to 12 carbon atoms, N,N-dialkylamino group with 2 to 12 carbon atoms, N-alkylamine group with 1 to 12 carbon atoms Sulfonyl group or N,N-dialkylamine sulfonyl group with 2 to 12 carbon atoms.

Q ¹ , Q ² and Q ³ independently represent -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, -CO- or O-, and R ^2' and R ^3' independently represent Represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms.

J ¹ and J ² independently represent a carbon atom or a nitrogen atom.

Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

W ¹ and W ² independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer from 0 to 6.

Examples of the aromatic hydrocarbon groups in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthracenyl, phenanthrenyl, and biphenyl groups. Preferred ones are phenyl, Naphthyl, more preferably phenyl. Examples of the aromatic heterocyclic group include: furyl, pyrrolyl, thienyl, pyridyl, thiazolyl, benzothiazolyl, and other carbon atoms containing at least one heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, etc., with a carbon number of 4~ The aromatic heterocyclic group 20 is preferably furyl, thienyl, pyridyl, thiazolyl or benzothiazolyl.

Y ¹ , Y ² and Y ³ may each independently be a substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from a collection of aromatic rings. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from a collection of aromatic rings.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group with 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group with 1 to 12 carbon atoms, and Z ⁰ is even more preferably is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

Q ¹ , Q ² and Q ³ are preferably -NH-, -S-, -NR ^2' -, -O-, and R ^2' is preferably a hydrogen atom. Among them, -S-, -O- and -NH- are particularly preferred.

Among formulas (Ar-1) to (Ar-23), from the viewpoint of molecular stability, formula (Ar-6) and formula (Ar-7) are preferred.

環、嘧啶環、吲哚環、喹啉環、異喹啉環、嘌呤環、吡咯啶環等。該芳香族雜環基亦可具有取代基。又，Y¹亦可為可與其所鍵結之氮原子及Z⁰一同被上述取代之多環系芳香族烴基或多環系芳香族雜環基。例如可列舉：苯并呋喃環、苯并噻唑環、苯并

唑環等。 In the formulas (Ar-16) ~ (Ar-23), Y ¹ can also form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those described above as aromatic heterocyclic rings that Ar may have. Examples include: pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyridine ring, etc.

ring, pyrimidine ring, indole ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. The aromatic heterocyclic group may have a substituent. Moreover, Y ¹ may also be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted as described above together with the nitrogen atom to which it is bonded and Z ⁰ . Examples include: benzofuran ring, benzothiazole ring, benzo

Azole ring etc.

The content of the component derived from the polymerizable liquid crystal compound in the optically anisotropic film of the present invention is preferably 70 to 99.5% by mass, more preferably 80 to 99% by mass, and more preferably 80% to 99% by mass relative to the mass of the optically anisotropic film. It is 85-98 mass %, and more preferably, it is 90-95 mass %. If derived from polymeric liquid When the content of the crystalline compound component is within the above range, the alignment of the optically anisotropic film can be improved. In addition, in this specification, the component derived from a polymerizable liquid crystal compound means a polymerizable liquid crystal compound and a polymer of a polymerizable liquid crystal compound.

The liquid crystal phase transition temperature of the polymerizable liquid crystal compound is 120°C or higher, and the upper limit of the liquid crystal phase transition temperature is usually 200°C or lower, preferably 180°C or lower. Furthermore, the liquid crystal phase transition temperature of the polymerizable liquid crystal compound can be measured using a differential scanning calorimeter, for example, by the method described in the Examples.

The optically anisotropic film of the present invention contains an organic solvent with a boiling point of 120°C or above, and the content of the organic solvent is 100 to 2000 ppm relative to the mass of the optically anisotropic film. In this way, the optically anisotropic film of the present invention has a relatively small solvent content, so it can have excellent heat resistance and can suppress changes in phase difference even at high temperatures. Furthermore, if the solvent content (solvent balance) of the obtained optically anisotropic film is within the above range, the polymerizable liquid crystal compound can be optimally aligned in a liquid crystal state in the drying step during production of the optically anisotropic film. Alignment in a certain amount of organic solvent can inhibit crystallization before alignment and the generation of alignment defects. Therefore, the optically anisotropic film of the present invention can exhibit sufficient alignment and has excellent optical properties such as low haze. Furthermore, the optically anisotropic film of the present invention may also contain an organic solvent with a boiling point less than 120°C, but usually does not substantially contain an organic solvent with a boiling point less than 120°C. Substantially not included means that the mass of organic solvents with a boiling point less than 120°C relative to the optically anisotropic film is preferably 100 ppm or less, more preferably 50 ppm or less, further preferably 10 ppm or less, and particularly preferably 0 ppm. Furthermore, the solvent content (remaining amount of solvent) of the organic solvent can be measured by thermal desorption gas chromatography mass spectrometry, for example, by the method described in the Examples.

The content of the organic solvent with a boiling point of 120° C. or higher relative to the mass of the optically anisotropic film is preferably 100 to 1500 ppm, more preferably 150 to 1000 ppm, and further preferably 200 to 500 ppm. If the content of the organic solvent is more than the above lower limit, it is easy to improve the alignment of the optically anisotropic film, and it is easy to improve the optical properties of the optically anisotropic film such as low haze. Moreover, if it is below the said upper limit, the heat resistance of an optically anisotropic film will be easy to improve.

The content of the organic solvent with a boiling point of 120° C. or higher relative to the mass of the polymerizable liquid crystal compound is preferably 100 to 1500 ppm, more preferably 150 to 1000 ppm, and still more preferably 200 to 500 ppm. If the content of the organic solvent is more than the above lower limit, it is easy to improve the alignment of the optically anisotropic film, and it is easy to improve the optical properties of the optically anisotropic film such as low haze. Moreover, if it is below the said upper limit, the heat resistance of an optically anisotropic film will be easy to improve.

The organic solvent having a boiling point of 120° C. or higher is preferably a solvent that can dissolve the polymerizable liquid crystal compound and is inert to the polymerization reaction of the polymerizable liquid crystal compound, and can be appropriately selected according to the polymerizable liquid crystal compound used. Specific examples include: amide solvents such as N-methyl-2-pyrrolidone (NMP, boiling point 202°C), diethyl acetamide (boiling point 165°C), and dimethylformamide (boiling point 153°C). ; Propylene glycol monomethyl ether acetate (PGMEA, boiling point 146°C), butyl acetate (boiling point 126°C), ethylene glycol methyl ether acetate (boiling point 145°C), γ-butyrolactone (GBL, boiling point 204°C) ) and ethyl lactate (boiling point 155℃) and other ester solvents; ketone solvents such as cyclopentanone (boiling point 130℃), cyclohexanone (boiling point 157℃) and 2-heptanone (boiling point 151℃); ethylene glycol (boiling point 197℃), propylene glycol (boiling point 187℃), ethylene glycol methyl ether (boiling point 124℃), ethylene glycol butyl ether (boiling point 171℃) and propylene glycol monomethyl ether (boiling point 121℃) and other alcohol solvents; xylene (boiling point 138~144℃) and other aromatic hydrocarbon solvents; chlorobenzene (boiling point 131°C) and other chlorine-containing solvents. The organic solvent can be used alone or in combination of two or more. The boiling point of the organic solvent is preferably 125°C or higher, more preferably 130°C or higher. If the boiling point of the above-mentioned organic solvent is above the above-mentioned lower limit, the solvent content (remaining amount of solvent) of the optically anisotropic film can be easily adjusted to a specific range, and therefore the heat resistance, alignment, and properties of the optically anisotropic film can be improved. Optical properties such as low haze. In addition, the upper limit of the boiling point of the organic solvent is not particularly limited, but is usually 250°C or less.

<Polymerization initiator>

The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention may contain a polymerization initiator. The polymerization initiator is a compound that generates reactive species with the help of heat or light and can initiate the polymerization reaction of a polymerizable liquid crystal compound or the like. Examples of reactive species include active species such as free radicals, cations, and anions. Among them, from the viewpoint of easy reaction control, a photopolymerization initiator that generates radicals (active radicals) by light irradiation is preferred.

化合物、錪鹽及鋶鹽。具體可列舉：豔佳固(Irgacure、註冊商標)907、豔佳固184、豔佳固651、豔佳固819、豔佳固250、豔佳固369、豔佳固379、豔佳固127、豔佳固2959、豔佳固754、豔佳固379EG(以上為BASF日本股份有限公司製造)、Seikuol BZ、Seikuol Z、Seikuol BEE(以上為精工化學股份有限公司製造)、kayacure(kayacure)BP100(日本化藥股份有限公司製造)、kayacure UVI-6992(Dow公司製造)、Adeka Optomer SP-152、Adeka Optomer SP-170、Adeka Optomer N-1717、Adeka Optomer N- 1919、ADEKAARKLS NCI-831、ADEKAARKLS NCI-930(以上為ADEKA股份有限公司製造)、TAZ-A、TAZ-PP(以上為Nihon SiberHegner公司製造)及TAZ-104(三和化學公司製造)。光聚合起始劑可單獨使用，或將兩種以上組合使用。該等光聚合起始劑之中，就能夠有效率地利用波長350nm以上之紫外線之觀點而言，較佳為α-苯乙酮系光聚合起始劑、肟系光聚合起始劑。 Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, and trisulfide compounds.

Compounds, iodonium salts and strontium salts. Specific examples include: Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Seikuol 2959, Seikuol 754, Seikuol 379EG (the above are manufactured by BASF Japan Co., Ltd.), Seikuol BZ, Seikuol Z, Seikuol BEE (the above are manufactured by Seiko Chemical Co., Ltd.), kayacure (kayacure) BP100 ( Manufactured by Nippon Kayaku Co., Ltd.), kayakure UVI-6992 (manufactured by Dow Corporation), Adeka Optomer SP-152, Adeka Optomer SP-170, Adeka Optomer N-1717, Adeka Optomer N-1919, ADEKAARKLS NCI-831, ADEKAARKLS NCI -930 (the above are manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ-PP (the above are manufactured by Nihon SiberHegner Co., Ltd.) and TAZ-104 (the above are manufactured by Sanwa Chemical Co., Ltd.). The photopolymerization initiator can be used alone or in combination of two or more. Among these photopolymerization initiators, α-acetophenone-based photopolymerization initiators and oxime-based photopolymerization initiators are preferred from the viewpoint of being able to efficiently utilize ultraviolet rays with a wavelength of 350 nm or more.

Examples of the α-acetophenone photopolymerization initiator include: 2-methyl-2-morpholinyl-1-(4-methylthiophenyl)propan-1-one, 2-dimethyl Amino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one and 2-dimethylamino-1-(4-morpholinylphenyl)-2-( 4-methylphenylmethyl)butan-1-one, etc., more preferably 2-methyl-2-morpholinyl-1-(4-methylthiophenyl)propan-1-one and 2 -Dimethylamino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one. Commercially available α-acetophenone photopolymerization initiators include Seikuol 369, 379EG, and 907 (manufactured by BASF Japan Co., Ltd.) and Seikuol BEE (manufactured by Seiko Chemical Co., Ltd.).

化合物或肟酯型咔唑化合物，就感度之觀點而言，更佳為肟酯型咔唑化合物。作為肟酯型咔唑化合物，例如可列舉：1,2-辛二酮、1-[4-(苯硫基)-2-(O-苯甲醯肟)]、乙酮、1-[9-乙基-6-(2-甲基苯甲醯基)-9H-咔唑- 3-基]-1-(O-乙醯肟)等。作為肟酯型咔唑化合物之市售品，可列舉：豔佳固OXE-01、豔佳固OXE-02、豔佳固OXE-03(以上為BASF日本股份有限公司製造)、Adeka Optomer N-1919、ADEKAARKLS NCI-831(以上為ADEKA股份有限公司製造)等。 The oxime-based photopolymerization initiator generates methyl radicals by irradiating light. This methyl radical causes polymerization of the polymerizable liquid crystal compound in the deep portion of the optically anisotropic film to proceed appropriately. Furthermore, from the viewpoint of more efficiently advancing the polymerization reaction in the deep portion of the optically anisotropic film, it is preferable to use a photopolymerization initiator that can efficiently utilize ultraviolet rays with a wavelength of 350 nm or more. As a photopolymerization initiator that can efficiently utilize ultraviolet rays with a wavelength of 350 nm or more, three is preferred.

compound or an oxime ester type carbazole compound, and from the viewpoint of sensitivity, an oxime ester type carbazole compound is more preferred. Examples of the oxime ester type carbazole compound include: 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], ethyl ketone, 1-[9 -Ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyl oxime), etc. Commercially available products of oxime ester type carbazole compounds include: Adeka Optomer OXE-01, Adeka Optomer OXE-02, Adeka Optomer OXE-03 (the above products are manufactured by BASF Japan Co., Ltd.), and Adeka Optomer N- 1919, ADEKAARKLS NCI-831 (the above are manufactured by ADEKA Co., Ltd.), etc.

When the polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention contains a polymerization initiator, the content of the polymerization initiator can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound, but relative to the polymerization 100 parts by mass of the liquid crystal compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and further preferably 1 to 15 parts by mass. If the content of the polymerization initiator is within the above range, the reaction of the polymerizable groups will proceed sufficiently, an optically anisotropic film with sufficient hardness will be obtained, and the alignment of the polymerizable liquid crystal compound will not be easily disturbed.

<Polymerization inhibitor>

The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention may contain a polymerization inhibitor. The degree of progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by the polymerization inhibitor.

As the polymerization inhibitor, those conventionally known in the field of optical films can be used. Examples thereof include primary antioxidants such as phenolic antioxidants, amine antioxidants, quinone antioxidants, and nitroso antioxidants. Oxidants; secondary antioxidants such as phosphorus antioxidants and sulfur antioxidants, etc. The polymerization inhibitor can be used alone or in combination of two or more. Among these, primary antioxidants such as phenolic antioxidants are preferred from the viewpoint of capturing free radicals derived from the polymerization initiator, and further preferred from the viewpoint of not inhibiting the polymerization of the liquid crystal cured film after drying. It is a primary antioxidant with a molecular weight of less than 500.

Phenolic antioxidants are antioxidants having a phenolic hydroxyl group in the molecule, preferably those having an alkyl group adjacent to the phenolic hydroxyl group. In this specification, antioxidants having a phenolic hydroxyl group and a phosphate structure or a phosphite structure are classified as phosphorus antioxidants.

-2,4,6(1H,3H,5H)-三酮、1,3,5-三((4-第三丁基-3-羥基-2,6-二甲苯基)甲基)-1,3,5-三

-2,4,6(1H,3H,5H)-三酮、硫代二乙烯雙[3-(3,5-二-第三丁基-4-羥基苯基)丙酸酯]、苯丙酸、3,5-雙(1,1-二甲基乙基)-4-羥基、C7-C9側鏈烷基酯、4,6-雙(辛硫基甲基)-鄰甲酚、Irganox(註冊商標)3125(BASF公司製造)、2,4-雙(正辛硫基)-6-(4-羥基3',5'-二-第三丁基苯胺)-1,3,5-三

、3,9-雙(2-(3-(3-第三丁基-4-羥基-5-甲基苯基)丙醯氧基)-1,1-二甲基乙基)-2,4,8,10-四氧雜螺(5,5)十一烷、二丁基羥基甲苯(2,6-二-第三丁基-對甲酚，有時稱為BHT)、Sumilizer(註冊商標)BHT(住友化學(股)製造)、Sumilizer(註冊商標)GA-80(住友化學(股)製造)、Sumilizer(註冊商標)GS(住友化學(股)製造)、Cyanox(註冊商標)1790(Cytec(股)製造)及維生素E(衛材(股)製造)等。 Examples of phenolic antioxidants include: 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-butylene-bis(3 -Methyl-6-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2-tert-butyl 6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, tetrakis[methylene-3-(3,5-di -Tertibutyl-4-hydroxyphenyl)propionate]methane, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3-(3 ,5-Di-tert-butyl-4-hydroxyphenyl)octadecylpropionate, 3,3',3",5,5',5"-hexa-tert-butyl-a,a ',a"-(mesitylene-2,4,6-trisyl)tris-p-cresol, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-three

-2,4,6(1H,3H,5H)-trione, 1,3,5-tris((4-tert-butyl-3-hydroxy-2,6-xylyl)methyl)-1 ,3,5-three

-2,4,6(1H,3H,5H)-trione, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], phenylpropanate Acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy, C7-C9 side chain alkyl ester, 4,6-bis(octylthiomethyl)-o-cresol, Irganox (Registered trademark) 3125 (manufactured by BASF), 2,4-bis(n-octylthio)-6-(4-hydroxy3',5'-di-tert-butylaniline)-1,3,5- three

, 3,9-bis(2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl)-2, 4,8,10-tetraoxasspiro(5,5)undecane, dibutylhydroxytoluene (2,6-di-tert-butyl-p-cresol, sometimes called BHT), Sumilizer (registered Trademarks) BHT (manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer (registered trademark) GA-80 (manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer (registered trademark) GS (manufactured by Sumitomo Chemical Co., Ltd.), Cyanox (registered trademark) 1790 (manufactured by Cytec Co., Ltd.) and vitamin E (manufactured by Eisai Co., Ltd.), etc.

、N-甲基啡噻

、N-乙基啡噻

、3,7-二辛基啡噻

、啡噻

羧酸酯、吩哂

等啡噻

系抗氧化劑。 Amine antioxidants are antioxidants that have an amine group in the molecule. Examples of amine-based antioxidants include 1-naphthylamine, phenyl-1-naphthylamine, p-octylphenyl-1-naphthylamine, p-nonylphenyl-1-naphthylamine, and p-dodecylamine. Naphthylamine-based antioxidants such as phenyl-1-naphthylamine and phenyl-2-naphthylamine; N,N'-diisopropyl-p-phenylenediamine, N,N'-diisobutyl-p-phenylenediamine Diamine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-β-naphthyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine , N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine, dioctyl-p-phenylenediamine, benzene Phenylenediamine-based antioxidants such as ylhexyl-p-phenylenediamine and phenyloctyl-p-phenylenediamine; dipyridylamine, diphenylamine, p,p'-di-n-butyldiphenylamine, p,p'- Di-tert-butyldiphenylamine, p,p'-di-tert-pentyldiphenylamine, p,p'-dioctyldiphenylamine, p,p'-dinonyldiphenylamine, p,p'- Didecyldiphenylamine, p,p'-di(dodecyl)diphenylamine, p,p'-distyryldiphenylamine, p,p'-dimethoxydiphenylamine, 4,4'- Diphenylamine-based antioxidants such as bis(4-α,α-dimethylbenzoyl)diphenylamine, p-isopropoxydiphenylamine, and dipyridylamine;

, N-methylphenidate

, N-ethylphenidine

, 3,7-dioctylphenidine

, phenanthrene

Carboxylic acid ester, phenol

Isopterin

It is an antioxidant.

Phosphorus-based antioxidants are antioxidants having a phosphate structure or a phosphite structure. Examples of phosphorus-based antioxidants include: 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyl Tributyldibenzo[d,f][1,3,2]dioxaphosphocycloheptane, tris(2,4-di-tert-butylphenyl)phosphite, diphenylisophosphite Octyl ester, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, diphenyl isodecyl phosphite, diphenyl isodecyl phosphite , triphenyl phosphate, tributyl phosphate, distearyl pentaerythritol diphosphite, cyclic neopentane tetrayl bis (2,6-di-tert-butyl-4-methylphenyl) phosphate Phosphate ester, 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butylbenzo[d ,f][1,3,2]dioxaphosphonium ring Heptane, tris(nonylphenyl) phosphite, tris(mono-& dinonylphenyl mixed) phosphite, diphenyl mono(tridecyl)phosphite, 2,2'- Ethyl bis (4,6-di-tert-butylphenol) fluorophosphite, phenyl diisodecyl phosphite, tris (2-ethylhexyl) phosphite, tris (isodecyl) phosphite Ester, tris(tridecyl)phosphite, 4,4'-biphenyl-di-tetrakis(2,4-di-tert-butylphenyl)phosphite, 4,4'-biphenyl Isopropyldiphenyltetraalkyl (C12-C15) diphosphite, 4,4'-butylene bis(3-methyl-6-tert-butylphenyl)-bis(tridecyl) Phosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol-di-phosphite, cyclic neopentane tetrayl bis(2 ,6-di-tert-butyl-4-methylphenyl-phosphite), 1,1,3-tris(2-methyl-4-di(tridecyl)phosphite-5- tert-butylphenyl)butane, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenyl diphosphite, tri-2 phosphorous acid -Ethylhexyl, triisodecyl phosphite, tris(octadecyl)phosphite, phenyldiisodecyl phosphite, trilauryl trithiophosphite, distearyl pentaerythritol diphosphite Ester, tris(nonylphenyl)phosphite tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxa Phosphine-6-yl]oxy]ethyl]amine, bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethyl phosphite, Adekastab (registered trademark) 329K (manufactured by ADEKA Co., Ltd.), Adekastab (registered trademark) PEP36 (manufactured by ADEKA Co., Ltd.), Adekastab (registered trademark) PEP-8 (manufactured by ADEKA Co., Ltd.), Sandstab (registered trademark) P-EPQ (Clariant Corporation Manufactured), Weston (registered trademark) 618 (manufactured by GE Company), Weston (registered trademark) 619G (manufactured by GE Company), Ultranox (registered trademark) 626 (manufactured by GE Company), 6-[3-(3-third -4-Hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetrakis-tert-butyldibenzo[d,f][1,3,2]dioxaphosphonium Cycloheptane) etc.

Sulfur-based antioxidants are antioxidants that have sulfur atoms in their molecules. Examples of sulfur-based antioxidants include dilauryl thiodipropionate, dimyristyl, distearyl, and the like. Thiodipropionate compounds; β-alkyl mercaptopropionate compounds of polyhydric alcohols such as tetrakis[methylene (3-dodecylthio)propionate]methane, etc.

When the polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.1 to 10 parts by mass, and 0.15 to 100 parts by mass of the polymerizable liquid crystal compound. 7 parts by mass, more preferably 0.2 to 5 parts by mass, and particularly preferably 0.2 to 1 part by mass. If the content of the polymerization inhibitor is within the above range, gelation during storage of the polymerizable liquid crystal composition can be prevented, and the occurrence of alignment defects in the obtained optically anisotropic film can be easily suppressed.

<Leveling agent>

The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention may also contain a leveling agent. The leveling agent has the function of adjusting the fluidity of the polymerizable liquid crystal composition and making the optically anisotropic film obtained by coating the composition flatter. Examples of the leveling agent include polysilicone leveling agents, polyacrylate leveling agents, perfluoroalkyl leveling agents, and the like. Specific examples include: DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all of the above are manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all of the above are manufactured by Shin-Etsu Chemical Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all of the above are manufactured by Momentive Advanced Materials Japan Contract Co., Ltd. ), electronic fluoride (fluorinert) (registered trademark) FC-72, fluorinert FC-40, fluorinert FC-43, fluorinert FC-3283 (all of the above are manufactured by Sumitomo 3M Co., Ltd.), MEGAFAC (registered trademark) R- 08. MEGAFAC R-30, MEGAFAC R-90, MEGAFAC F-410, MEGAFAC F-411, MEGAFAC F-443, MEGAFAC F-445, MEGAFAC F-470, MEGAFAC F-477, MEGAFAC F-479, MEGAFAC F-482, MEGAFAC F-483 (the above are all manufactured by DIC Co., Ltd.), Eftop (trade name) EF301, Eftop EF303, Eftop EF351, Eftop EF352 (all of the above are manufactured by Mitsubishi Materials Electronics Co., Ltd.), Surflon (registered trademark) S-381, Surflon S-382, Surflon S-383, Surflon S-393, Surflon SC-101, Surflon SC-105, KH-40, SA-100 (all of the above are manufactured by AGC Seimei Chemical Co., Ltd.), trade name E1830, trade name E5844 (Daikin Precision Chemical Research Institute Co., Ltd. ), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: BM, manufactured by Chemie Corporation), etc. These leveling agents can be used alone or in combination of two or more. Among these, polyacrylate leveling agents and perfluoroalkyl leveling agents are preferred.

The content of the leveling agent is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, it is preferable because, for example, the polymerizable liquid crystal compound can be easily aligned horizontally and the obtained optically anisotropic film tends to become smoother. The composition for forming an optically anisotropic layer may contain two or more types of leveling agents.

<Photosensitizer>

酮、9-氧硫

等

酮類；蒽及烷基醚等具有取代基之蒽類；啡噻

；紅螢烯。光敏劑可單獨使用，或將兩種以上組合使用。光敏劑之含量相對於聚 合性液晶化合物100質量份，較佳為0.01~10質量份，更佳為0.05~5質量份，進而較佳為0.1~3質量份。 The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention may contain a photosensitizer. The photosensitizer can sensitize the photopolymerization initiator. Examples of photosensitizers include:

Ketone, 9-oxysulfide

wait

Ketones; anthracenes with substituents such as anthracene and alkyl ethers; phenanthrene

;Rufluorene. The photosensitizer can be used alone or in combination of two or more. The content of the photosensitizer is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and further preferably 0.1 to 3 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound.

<Additive>

The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention may contain additives such as adhesive improvers, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. The content of the additive is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass relative to the mass of the solid component of the polymerizable liquid crystal composition constituting the optically anisotropic film. In addition, the solid content of a gravimetric liquid crystal composition means all components excluding volatile components such as solvents in the self-polymerizable liquid crystal composition.

The optically anisotropic film of the present invention is preferably a film having anisotropy in three-dimensional refractive index. The three-dimensional refractive index ellipsoid formed by the optically anisotropic film may also have biaxiality, but is preferably uniaxial. The optically anisotropic film may be a horizontally aligned liquid crystal cured film polymerized by a polymerizable liquid crystal compound that is aligned in a horizontal direction with respect to the plane of the optically anisotropic film, and may be a horizontally aligned liquid crystal cured film with respect to the plane of the optically anisotropic film. A vertically aligned liquid crystal cured film formed by polymerizing a polymerizable liquid crystal compound that is aligned along the vertical direction (the film thickness direction of the optically anisotropic film) can also be a mixed alignment liquid crystal cured film or a tilted alignment liquid crystal cured film.

In a preferred aspect of the present invention, the optically anisotropic film of the present invention is a cured film obtained by curing the above-mentioned polymerizable liquid crystal composition, and is aligned in a horizontal direction with respect to the plane of the optically anisotropic film. A horizontally aligned liquid crystal cured film formed by polymerizing a state polymerizable liquid crystal compound.

The above-mentioned horizontally aligned liquid crystal cured film preferably satisfies the optical characteristics represented by the following formula (2) with respect to the in-plane phase difference of light with wavelength λ nm, that is, R(λ), and more preferably satisfies the following formula (3) and the following The optical characteristics are represented by the following formula (4) and the following formula (5).

100nm≦Re(550)≦160nm…(2)

[In the formula, Re(550) represents the in-plane phase difference value (in-plane retardation) with respect to light with a wavelength of 550 nm]

Re(450)/Re(550)≦1.0…(3)

1.00≦Re(650)/Re(550)…(4)

[In the formula, Re(450) represents the in-plane phase difference value relative to the light with a wavelength of 450 nm, Re(550) represents the in-plane phase difference value relative to the light with a wavelength of 550 nm, and Re(650) represents the in-plane phase difference value relative to the light with a wavelength of 650 nm. In-plane phase difference value of light]

If "Re(450)/Re(550)" of the optically anisotropic film exceeds 1.0, the light leakage on the short wavelength side of the elliptically polarizing plate including the optically anisotropic film tends to increase. More preferably, it is 0.95 or less, and still more preferably, it is 0.92 or less.

The in-plane phase difference value of the optically anisotropic film can be adjusted according to the thickness of the optically anisotropic film. The in-plane retardation value is determined by the following equation (5). Therefore, in order to obtain the desired in-plane retardation value (Re(λ)), Δn(λ) and the film thickness d only need to be adjusted. The thickness of the horizontally aligned liquid crystal hardened layer is preferably 0.5~5 μm, more preferably 1~3 μm. The thickness of the horizontally aligned liquid crystal hardened layer can be measured by an interference film thickness meter, a laser microscope or a stylus film thickness meter. In addition, Δn (λ) depends on the molecular structure of the polymerizable liquid crystal compound described below.

Re(λ)=d×△n(λ)…(5)

(In the formula, Re(λ) represents the in-plane phase difference value at wavelength λ nm, d represents the film thickness, △n(λ) Represents the birefringence at wavelength λnm)

The haze of the optically anisotropic film of the present invention is preferably 2% or less, more preferably 1.5% or less, further preferably 1% or less, especially 0.5% or less, most preferably 0.3% or less. If the haze is below the above-mentioned upper limit, the optically anisotropic film of the present invention can clearly display a screen when applied to a display device. In addition, the lower limit value of haze is usually greater than 0. In addition, the haze can be measured using HAZE METER, for example, it can be measured by the method described in the Example.

From the viewpoint of thinning, the film thickness of the optically anisotropic film of the present invention is preferably 0.5 to 5 μm, more preferably 1 to 3 μm. Furthermore, the film thickness of the optically anisotropic film can be measured, for example, by an interference film thickness meter, a laser microscope, or a stylus type film thickness meter.

[Production method of optically anisotropic film]

The optically anisotropic film of the present invention is preferably formed on a substrate or an alignment film. Such an optically anisotropic film can be produced by a method including the following steps: coating a polymerizable liquid crystal composition containing an organic solvent with a boiling point of 120°C or higher and a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or higher. Spread on the substrate or alignment film to obtain a coating layer (hereinafter, also referred to as the "coating step"); dry the obtained coating layer at a drying temperature that does not reach the boiling point of the organic solvent, and automatically The coating layer removes the organic solvent while aligning the polymerizable liquid crystal compound (hereinafter also referred to as the "drying step"); and by polymerizing the aligned polymerizable liquid crystal compound, the polymerizable liquid crystal layer is hardened to obtain Optically anisotropic film (hereinafter also referred to as "hardening step").

Furthermore, when the polymerizable liquid crystal composition is formed on an alignment film, the alignment film is preferably formed on a substrate.

The polymerizable liquid crystal composition constituting the optically anisotropic film of the present invention can be prepared by mixing the above polymerizable liquid crystal compound and the above organic solvent, and optionally the above polymerization initiator and the above polymerization inhibitor by using a known method such as stirring. The agent, the above-mentioned leveling agent, the above-mentioned photosensitizer and the above-mentioned additive are mixed and prepared.

In the coating step, methods for coating the above-mentioned polymerizable liquid crystal composition on a substrate or an alignment film include, for example: extrusion coating, direct gravure coating, reverse gravure coating, CAP Coating method, slit coating method, die nozzle coating method, etc. In addition, a method of coating using a coater such as a dip coater, a rod coater, and a spin coater may also be used. Among these, the CAP coating method, the inkjet method, the dip coating method, the slit coating method, and the like can be used in a continuous roll-to-roll manner. Die nozzle coating method and coating method using rod coater. When applying in a roll-to-roll manner, the alignment film-forming composition or the like can also be coated on the substrate to form an alignment film, and then the polymerizable liquid crystal composition can be continuously coated on the obtained alignment film. superior.

烯系聚合物等聚烯烴；環狀烯烴系樹脂；聚乙烯醇；聚對苯二甲酸乙二酯；聚甲基丙烯酸酯；聚丙烯酸酯；三乙醯纖維素、二乙醯纖維素及乙酸纖維素丙酸酯等 纖維素酯；聚萘二甲酸乙二酯；聚碳酸酯；聚碸；聚醚碸；聚醚酮；聚苯硫醚及聚苯醚等樹脂。 Examples of the base material include glass base materials and film base materials. From the viewpoint of processability, a film base material is preferred, and a long roll-shaped film is more preferred since it can be produced continuously. Examples of the resin constituting the film base material include polyethylene, polypropylene,

Polyolefins such as olefinic polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; triacetyl cellulose, diacetyl cellulose and acetic acid Cellulose esters such as cellulose propionate; polyethylene naphthalate; polycarbonate; polystyrene; polyether styrene; polyetherketone; polyphenylene sulfide and polyphenylene ether and other resins.

Commercially available cellulose ester substrates include: "Fujitac Film" (manufactured by Fuji Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (the above are manufactured by Konica Minolta Opto Co., Ltd.), etc.

Examples of commercially available cyclic olefin-based resins include "Topas" (registered trademark) (manufactured by Ticona Co., Ltd., Germany), "ARTON" (registered trademark) (manufactured by JSR Co., Ltd.), "ZEONOR" (registered trademark) ), "ZEONEX" (registered trademark) (the above are manufactured by Japan Zeon Co., Ltd.) and "APEL" (registered trademark) (manufactured by Mitsui Chemicals Co., Ltd.). This cyclic olefin-based resin can be formed into a film by known methods such as solvent casting and melt extrusion to form a base material. Commercially available cyclic olefin-based resin base materials can also be used. Examples of commercially available cyclic olefin-based resin base materials include "S-SINA" (registered trademark), "SCA40" (registered trademark) (manufactured by Sekisui Chemical Industry Co., Ltd.), "ZEONOR Membrane" (registered trademark) Trademark) (manufactured by Japan Zeon Co., Ltd.) and "ARTON film" (registered trademark) (manufactured by JSR Co., Ltd.).

Among the resins constituting the base material, from the viewpoint of heat resistance, cyclic olefin-based resins and polyethylene terephthalate are preferred.

The thickness of the base material is preferably thinner in terms of quality that enables practical operation. However, if it is too thin, the strength decreases and the processability tends to deteriorate. The thickness of the substrate is usually 5~300μm, preferably 20~200μm. Furthermore, by peeling off the base material and transferring a single optically anisotropic film or a laminate of an optically anisotropic film and an alignment film, a further thinning effect can be obtained.

The alignment film has an alignment restricting force that aligns the polymerizable liquid crystal compound in a desired direction. The alignment film preferably has solvent resistance such that it does not dissolve when the polymerizable liquid crystal composition is coated, etc., and also has heat resistance for heat treatment for removal of the solvent or alignment of the polymerizable liquid crystal compound described below. By. Examples of the alignment film include: friction alignment film, photo alignment film, trench alignment film having a concave and convex pattern or a plurality of grooves on the surface, stretched film, etc. When applied to a long roll-shaped film, a photo-alignment film is preferred in terms of easy control of the alignment direction.

This alignment film facilitates alignment of polymerizable liquid crystal compounds. In addition, depending on the type of alignment film, rubbing conditions, or light irradiation conditions, various alignments such as vertical alignment, horizontal alignment, mixed alignment, and tilt alignment can be controlled.

The film thickness of the alignment film is usually 10~10000nm, preferably 10~1000nm, and more preferably 50~300nm.

唑、聚伸乙基亞胺、聚苯乙烯、聚乙烯吡咯啶酮、聚丙烯酸及聚丙烯酸酯類。配向性聚合物可單獨使用，或將兩種以上組合使用。 Examples of alignment polymers used for rubbing alignment films include polyamides or gelatins having amide bonds, polyamide imines having amide imine bonds and polyamide acid, which are hydrolysates thereof, and polyethylene. Alcohol, alkyl modified polyvinyl alcohol, polyacrylamide, poly

Azoles, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylate esters. Alignment polymers can be used alone or in combination of two or more.

The friction alignment film can usually be coated on a substrate by coating a composition obtained by dissolving an alignment polymer in a solvent (hereinafter also referred to as an alignment polymer composition), and then removing the solvent to form a coating film. The coating film is rubbed to impart an alignment regulating force.

The concentration of the aligning polymer in the aligning polymer composition only needs to be within the range where the aligning polymer is completely dissolved in the solvent. The content of the alignment polymer relative to the alignment polymer composition is preferably 0.1 to 20 mass%, more preferably 0.1 to 10 mass%.

Alignment polymer compositions are commercially available. Examples of commercially available alignment polymer compositions include Sunever (registered trademark, manufactured by Nissan Chemical Industry Co., Ltd.), Optomer (registered trademark, manufactured by JSR Co., Ltd.), and the like.

As a method of applying the alignment polymer composition to the base material, the same method as the method of applying the above-mentioned polymerizable liquid crystal composition to the base material or the alignment film can be cited. Examples of methods for removing the solvent contained in the alignment polymer composition include natural drying, ventilated drying, heat drying, and reduced pressure drying.

An example of the rubbing treatment method is a method of bringing the above-mentioned coating film into contact with a rotating friction roller around which a rubbing cloth is wound. When performing rubbing treatment, if masking is performed, a plurality of regions (patterns) with different alignment directions can be formed on the alignment film.

Photo alignment films usually include polymers or oligomers or monomers with photoreactive groups. When the optically anisotropic film is continuously formed, from the viewpoint of solvent resistance, etc., a polymer having a molecular weight of 5,000 or more is preferred, and from the viewpoint of affinity, the polymerizable liquid crystal compound has (meth)acrylene. In the case of a acyl group, an acrylic polymer is preferred. The photoalignment film can be used as follows Obtained by a method, that is, applying a composition including a polymer or oligomer or monomer with a photoreactive group and a solvent (hereinafter, also referred to as "photo alignment film forming composition") on the substrate, The solvent is dried and removed, and then polarized light (preferably polarized UV) is irradiated. The optical alignment film is more preferable in that the direction of the alignment restriction force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

A photoreactive group refers to a group that generates alignment energy by light irradiation. Specific examples include groups that participate in photoreactions that are the origin of alignment energy, such as alignment-induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, and photodecomposition reactions of molecules generated by light irradiation. As the photoreactive group, a group having an unsaturated bond, especially a double bond, is preferred, and a group having a carbon-carbon double bond (C=C bond) and a carbon-nitrogen double bond (C=N bond) is particularly preferred. , at least one of the groups consisting of nitrogen-nitrogen double bonds (N=N bonds) and carbon-oxygen double bonds (C=O bonds).

Examples of the photoreactive group having a C=C bond include vinyl, polyalkenyl, stilbene, styrylpyridinyl, styrylpyridinyl, chalcone and cinnamyl groups. Examples of the photoreactive group having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of the photoreactive group having an N=N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a disazo group, a formazan group, and an azobenzene oxide structure. the foundation. Examples of the photoreactive group having a C=O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may also have substituents such as alkyl group, alkoxy group, aryl group, allyloxy group, cyano group, alkoxycarbonyl group, hydroxyl group, sulfonic acid group, and halogenated alkyl group.

Groups participating in the photodimerization reaction or the photocrosslinking reaction are preferred in terms of excellent alignment properties. Among them, the preferred ones are photoreactive groups that participate in the photodimerization reaction, depending on the amount of polarized light irradiation required for alignment. In terms of a small amount and the ease of obtaining a photo-alignment film with excellent thermal stability or time-stability, cinnamyl groups and chalcone groups are preferred. The polymer having a photoreactive group is particularly preferably one having a cinnamyl group such that the terminal portion of the side chain of the polymer has a cinnamic acid structure or a cinnamic acid ester structure.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted according to the type of the polymer or monomer or the thickness of the target photo-alignment film, and is preferably set to at least 0.2 mass. % or more, more preferably in the range of 0.3 to 10 mass %.

As a method of applying the composition for forming a photo-alignment film to a base material, the same method as the method of applying the above-mentioned polymerizable liquid crystal composition to a base material or an alignment film can be cited. As a method for removing the solvent from the composition for forming a photo-alignment film after coating, the same method as the method for removing the solvent from the alignment polymer composition can be cited.

In order to irradiate polarized light, the polarized light is irradiated directly to the composition for forming a photo alignment film coated on the substrate by removing the solvent, or the polarized light is irradiated from the side of the substrate, and the polarized light is transmitted through the substrate and irradiated. Both are available. Moreover, it is preferable if this polarized light is substantially parallel light. The wavelength of the polarized light irradiated can be a wavelength range in which the photoreactive groups of the polymer or monomer having photoreactive groups can absorb light energy. Specifically, UV (ultraviolet) having a wavelength in the range of 250 nm to 400 nm is particularly preferred. Examples of light sources that irradiate this polarized light include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halide lamps are preferred because of the greater luminous intensity of ultraviolet light with a wavelength of 313 nm. By irradiating light from the above-mentioned light sources through appropriate polarizing elements, it is possible to illuminate Shoots polarized UV. Examples of polarizing elements include polarizing filters, polarizing filters such as Gülen-Thompson and Gülen-Taylor, and wire grids. Among them, from the viewpoint of large area and heat resistance, a wire grid polarizing element is preferred. Furthermore, if shielding is performed during rubbing or polarized light irradiation, a plurality of regions (patterns) with different directions of liquid crystal alignment can be formed.

A groove alignment film is a film with a concave and convex pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is coated on a film having a plurality of linear grooves arranged at equal intervals, the liquid crystal molecules are aligned in the direction along the grooves.

As a method of obtaining a trench alignment film, the following method may be cited: exposing the surface of a photosensitive polyimide film through an exposure mask having pattern-shaped slits, and then developing and rinsing to form a concavo-convex pattern. ; Form a layer of UV cured resin before hardening on a plate-shaped master with grooves on the surface, move the resin layer toward the base material, and then harden; and press the roller-shaped master with a plurality of grooves against the formed The film of UV curable resin before curing on the base material forms unevenness, and then hardens.

In the drying step, while drying the coating layer obtained in the coating step at a drying temperature that does not reach the boiling point of the organic solvent, and removing the organic solvent from the coating layer, the polymerizable liquid crystal compound is converted into a liquid crystal Status alignment. At a drying temperature that does not reach the boiling point of the organic solvent, the organic solvent is removed so that the organic solvent content (remaining amount) of the obtained optically anisotropic film becomes 100 to 2000 ppm, so that it can be present in the coating layer through the drying step. A specific amount of organic solvent can therefore fully align the polymerizable liquid crystal compound in a liquid crystal state.

In one embodiment of the present invention, during the drying step, it is easy to improve the alignment or reduce the From the viewpoint of optical properties such as haze, it is preferable that the liquid crystal phase transition temperature of the polymerizable liquid crystal compound in the coating layer does not reach the boiling point of the organic solvent, and more preferably does not reach the drying temperature. Here, the liquid crystal phase transition temperature of the polymerizable liquid crystal compound tends to decrease in the organic solvent. Therefore, the liquid crystal phase transition temperature measured in the polymerizable liquid crystal compound (alone) is higher than that in the coating layer (including the organic solvent). Polymerizable liquid crystal compounds tend to have a high liquid crystal phase transition temperature. Therefore, the liquid crystal phase transition temperature of the polymerizable liquid crystal compound (alone) is preferably less than (the boiling point of the organic solvent + 40°C), more preferably less than (the boiling point of the organic solvent + 30°C), and still more preferably less than (The boiling point of the organic solvent + 20° C.), preferably less than (the boiling point of the organic solvent + 10° C.), and more preferably (the boiling point of the organic solvent - 80° C.) or more. If the liquid crystal phase transition temperature of the polymerizable liquid crystal compound (alone) is within the above range, it is easy to effectively suppress crystallization before alignment and the generation of alignment defects, and thereby it is easy to effectively improve the alignment or low haze of the obtained optically anisotropic film. and other optical properties. Furthermore, the liquid crystal phase transition temperature of the polymerizable liquid crystal compound (alone) can be measured using a differential scanning calorimeter, for example, by the method described in the Examples.

The drying temperature also depends on the type of polymerizable liquid crystal compound and solvent, but is preferably 50 to 140°C, and more preferably 80 to 130°C. If the drying temperature is higher than this range, the temperature of the hot air drying oven becomes unstable and the substrate may be deformed. If the drying temperature is lower than this range, sufficient alignment cannot be obtained. If the drying temperature is within the above range, it is advantageous in terms of heat resistance, alignment and optical properties of the optically anisotropic film.

In the hardening step, the polymerizable liquid crystal compound aligned by the drying step can be polymerized by a known method for polymerizing a compound having a polymerizable group. For example, light using irradiation with active energy rays can be used. polymerization.

The active energy ray to be irradiated is appropriately selected depending on the type of the polymerizable liquid crystal compound (especially the type of photopolymerizable functional group the polymerizable liquid crystal compound has), the type of photopolymerization initiator, and the amount thereof. Specific examples include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among them, ultraviolet light is preferred because it is easy to control the progress of the polymerization reaction and can be widely used as a photopolymerization device in the field, and it is more preferred that the photopolymerization device can be used for photopolymerization by ultraviolet light. The method of polymerization selects the type of polymerizable liquid crystal compound.

Examples of the light source of the active energy ray include: low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, halogen lamp, carbon arc lamp, tungsten lamp, gallium lamp, excimer laser, luminous wavelength LED (light-emitting diode) light source, chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp, etc. in the range of 380~440nm.

The intensity of ultraviolet irradiation is usually 10~3,000mW/cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the photopolymerization initiator. The time of irradiation with light is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, further preferably 0.1 second to 1 minute. If the ultraviolet irradiation intensity is irradiated once or multiple times, the cumulative light amount is 10~3,000mJ/cm ² , preferably 50~2,000mJ/cm ² , and more preferably 100~1,000mJ/cm ² . If the integrated light amount is within this range, the obtained optically anisotropic film tends to be sufficiently hardened, and the optically anisotropic film can be prevented from being colored.

[Elliptical polarizing plate and display device]

The elliptically polarizing plate of the present invention includes the above-mentioned optical anisotropic film and polarizing film. The optically anisotropic film may be formed on the alignment film laminated on the base material. The elliptically polarizing plate can be obtained by bonding the above-mentioned optically anisotropic film and the polarizing film via an adhesive. In a preferred aspect, the elliptically polarizing plate of the present invention has the above-mentioned base material, the above-mentioned alignment film, the above-mentioned optical anisotropic film, an adhesive layer and a polarizing film in this order.

In one embodiment of the present invention, when the optically anisotropic film is laminated on the polarizing film, it is preferable that the slow axis (optical axis) of the optically anisotropic film and the absorption axis of the polarizing film are substantially Layer at 45°. By laminating the optically anisotropic film so that the slow axis (optical axis) and the absorption axis of the polarizing film are substantially 45°, the function as an elliptically polarizing plate can be obtained. Furthermore, in fact, 45° is usually within the range of 45±5°.

As a polarizing film, a polarizing element with a polarizing function is included. Examples of the polarizing element include a stretched film to which a dye having absorption anisotropy is adsorbed, or a film in which a dye having absorption anisotropy is coated and aligned. Examples of dyes having absorption anisotropy include dichroic dyes.

A stretched film adsorbed with a pigment having absorption anisotropy is usually produced by the following steps: uniaxially stretching a polyvinyl alcohol-based resin film; and dyeing the polyvinyl alcohol-based resin film with a dichroic pigment to make it The dichroic pigment is adsorbed; the polyvinyl alcohol-based resin film adsorbed with the dichroic pigment is treated with a boric acid aqueous solution; and after being treated with the boric acid aqueous solution, water is washed. A polarizing film is obtained by bonding the polarizing element obtained in this manner to a transparent protective film. Examples of dichroic dyes include iodine or dichroic organic dyes. Examples of dichroic organic dyes include dichroic direct dyes containing disazo compounds such as C.I.DIRECT RED 39. Dyes, and dichroic direct dyes containing triazo, tetraazo and other compounds. As mentioned above, the thickness of the polarizing element obtained by uniaxially stretching a polyvinyl alcohol-based resin film, dyeing with a dichroic dye, boric acid treatment, washing with water, and drying is preferably 5 to 40 μm.

Examples of a film obtained by coating and aligning a dye having absorption anisotropy include a film obtained by coating a composition containing a dichroic dye having liquid crystallinity, or a film obtained by coating a composition containing a dichroic dye and a polymerizable dye. Films obtained from compositions of liquid crystal compounds, etc. A thinner film coated with a pigment having absorption anisotropy is better, but if it is too thin, the strength will decrease and the processability will tend to deteriorate. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5~3 μm. In terms of obtaining a hard film, it is preferable to apply a composition containing a dichroic dye and a polymerizable liquid crystal compound, and form a polymer film in a state in which the polymerizable liquid crystal compound is aligned. In terms of polarization performance, it is more preferable that the polymerizable liquid crystal compound has a smectic liquid crystal phase and forms a polymer film in a smectic liquid crystal phase state. Specific examples of such polarizing elements include Japanese Patent No. 4719156, Japanese Patent No. 4937252, Japanese Patent No. 5776063, Japanese Patent No. 5923941, Japanese Patent No. 5982762, Japanese Patent No. 6006485, and Japanese Patent No. 6036452. No., Japanese Patent No. 6098053, Japanese Patent No. 6132049, etc.

Furthermore, the elliptically polarizing plate of the present invention may include an optically anisotropic film, a polarizing film, an adhesive (adhesive layer), a base material, and other layers besides the alignment film. Examples of other layers include an isotropic protective film, a hard coat layer, and the like.

The present invention includes a display device including the above-mentioned elliptically polarizing plate. The display device can be used by The elliptically polarizing plate is preferably obtained by bonding the optically anisotropic film of the elliptically polarizing plate to a display device via an adhesive. Since the elliptically polarizing plate and the display device including the elliptically polarizing plate of the present invention include the optical anisotropic film, they have excellent heat resistance and excellent optical properties such as low haze, allowing the display to display clearly. A display device is a device with a display mechanism, including a light-emitting element or a light-emitting device as a light source. Examples of display devices include: liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FED, etc.) , surface field emission display device (SED)), electronic paper (display device using electronic ink or electrophoretic elements), plasma display device, projection display device (display device with grating light valve imaging system (GLV), digital micro Mirror device (DMD) display device, etc.) and piezoelectric ceramic display, etc. The liquid crystal display device also includes any one of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-viewing type liquid crystal display device, and a projection type liquid crystal display device. These display devices may be display devices that display two-dimensional images or may be three-dimensional display devices that display three-dimensional images. In particular, the display device including the elliptically polarizing plate of the present invention is preferably an organic EL display device and a touch panel display device.

As an adhesive for bonding the polarizing film and the optically anisotropic film in the formation of the elliptically polarizing plate, or as an adhesive for bonding the elliptically polarizing plate and the surface of the display device during the formation of the display device. , can be listed as: pressure-sensitive adhesives, drying curing adhesives and chemical reaction adhesives. Examples of chemical reaction type adhesives include active energy ray curing type adhesives. As an adhesive in the formation of an elliptically polarizing plate, an adhesive layer formed of a pressure-sensitive adhesive, a dry curing adhesive, or an active energy ray curing adhesive is preferred. As an adhesive in the formation of a display device The agent is preferably a pressure-sensitive adhesive or an active energy ray-hardening adhesive.

Pressure-sensitive adhesives usually contain polymers and may also contain solvents.

Examples of the polymer include acrylic polymers, polysiloxane polymers, polyesters, polyurethanes, polyethers, and the like. Among them, acrylic adhesives containing acrylic polymers have excellent optical transparency, moderate wettability or cohesion, excellent adhesion, high weather resistance or heat resistance, and are not easily susceptible to heating or humidification conditions. It is preferable because it does not cause swelling or peeling.

The acrylic polymer is preferably a (meth)acrylate in which the alkyl group of the ester part is an alkyl group having 1 to 20 carbon atoms such as methyl, ethyl or butyl (hereinafter, acrylate, methyl is sometimes referred to as Acrylates are collectively called (meth)acrylates, and sometimes acrylic acid and methacrylic acid are collectively called (meth)acrylic acid) and (meth)acrylic acid or (meth)acrylic acid hydroxyethyl ester and other functional groups (meth) ) Copolymer of acrylic monomers.

A pressure-sensitive adhesive containing such a copolymer is preferred because it has excellent adhesion and can be relatively easily removed without leaving any paste residue on the display device when it is attached to the display device and then removed. The glass transition temperature of the acrylic polymer is preferably 25°C or lower, more preferably 0°C or lower. The mass average molecular weight of this acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents listed above as the organic solvents. Pressure-sensitive adhesives may also contain light diffusing agents. The light diffusing agent is an additive that imparts light diffusing properties to the adhesive, and may be fine particles having a refractive index different from the refractive index of the polymer contained in the adhesive. Examples of the light diffusing agent include fine particles containing inorganic compounds and organic compounds (polymer). Compound) particles. Most polymers included as active ingredients in adhesives, including acrylic polymers, have a refractive index of about 1.4 to 1.6. Therefore, it is best to appropriately select a light diffusing agent with a refractive index of 1.2 to 1.8. . The refractive index difference between the polymer and the light diffusing agent contained as active ingredients in the adhesive is usually 0.01 or more. From the viewpoint of the brightness and display properties of the display device, the difference is preferably 0.01 to 0.2. The microparticles used as the light diffusing agent are preferably spherical microparticles, which are also close to monodispersed microparticles, and more preferably microparticles with an average particle size of 2 to 6 μm. The refractive index is measured by a general minimum deflection method or an Abbe refractometer.

Examples of fine particles containing an inorganic compound include aluminum oxide (refractive index: 1.76), silicon oxide (refractive index: 1.45), and the like. Examples of fine particles containing organic compounds (polymers) include: melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50) ~1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and polysiloxane beads ( Refractive index 1.46) etc. The content of the light diffusing agent is usually 3 to 30 parts by mass relative to 100 parts by mass of the polymer.

The thickness of the pressure-sensitive adhesive is determined based on its adhesion strength, etc., so there is no special limit, but it is usually 1~40μm. In terms of workability or durability, the thickness is preferably 3 to 25 μm, and more preferably 5 to 20 μm. By setting the thickness of the adhesive layer formed of the adhesive to 5~20 μm, the brightness of the display device can be maintained when the display device is viewed from the front or when viewed from an angle, and blur or spots in the display image are less likely to occur.

The dry curing adhesive may also contain a solvent.

Examples of dry-curable adhesives include polymers of monomers having protic functional groups such as hydroxyl, carboxyl, or amine groups and ethylenically unsaturated groups; or polyurethane resins as the main component and compositions containing cross-linking agents or curing compounds such as polyhydric aldehydes, epoxy compounds, epoxy resins, melamine compounds, zirconium oxide compounds, and zinc compounds. Examples of polymers of monomers having protonic functional groups such as hydroxyl, carboxyl or amine groups and ethylenically unsaturated groups include: ethylene-maleic acid copolymer, itaconic acid copolymer, acrylic acid copolymer, propylene Amide copolymers, saponified products of polyvinyl acetate, and polyvinyl alcohol resins, etc.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, and hydroxymethyl-modified polyvinyl alcohol. Vinyl alcohol, and amine-modified polyvinyl alcohol, etc. The content of the polyvinyl alcohol resin in the water-based adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass relative to 100 parts by mass of water.

Examples of the polyurethane resin include polyester-based ionopolymer polyurethane resin and the like. The polyester ionopolymer type polyurethane resin described here is a polyurethane resin having a polyester skeleton and a small amount of ionic components (hydrophilic components) introduced therein. Since the ionomer-type polyurethane resin does not use an emulsifier and emulsifies in water to become latex, it can be made into a water-based adhesive. When using a polyester-based ionomer-type polyurethane resin, it is effective to prepare a water-soluble epoxy compound as a cross-linking agent.

Examples of the epoxy resin include polyamide polyamines obtained by the reaction of polyalkylene polyamines such as diethylenetriamine or triethylenetetramine and adipic dicarboxylic acid. Polyamide epoxy resin obtained by reacting epichlorohydrin, etc. Commercially available products of this polyamide epoxy resin include: "Sumirez Resin (registered trademark) 650" and "Sumirez Resin 675" (the above is Sumika Chemtex Co., Ltd.), "WS-525" (manufactured by Japan PMC Co., Ltd.), etc. When preparing an epoxy resin, the added amount is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass relative to 100 parts by mass of the polyvinyl alcohol resin.

The thickness of the adhesive layer formed from the dry curing adhesive is usually 0.001~5 μm, preferably 0.01~2 μm, and further preferably 0.01~0.5 μm. If the adhesive layer formed by the dry curing adhesive is too thick, the elliptically polarizing plate will easily have poor appearance.

The active energy ray curable adhesive may contain a solvent. Active energy ray curable adhesive is an adhesive that hardens when exposed to active energy rays.

Examples of active energy ray curable adhesives include: cationic polymerizable adhesives containing an epoxy compound and a cationic polymerization initiator; radical polymerizable adhesives containing an acrylic curing component and a radical polymerization initiator. ; Adhesives containing both a cationically polymerizable hardening component such as an epoxy compound and a radically polymerizable hardening component such as an acrylic compound, and further containing a cationic polymerization initiator and a radical polymerization initiator; and does not include These polymerization initiators, adhesives hardened by electron beam irradiation, etc.

Among them, a radically polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, and a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator are preferred. type adhesive. Examples of the acrylic curing component include (meth)acrylic acid esters such as methyl (meth)acrylate and hydroxyethyl (meth)acrylate, and (meth)acrylic acid. The active energy ray curable adhesive containing an epoxy compound may further contain compounds other than the epoxy compound. Examples of compounds other than epoxy compounds include oxygen heterocycles Butane compounds or acrylic compounds, etc.

Examples of the radical polymerization initiator include the above-mentioned photopolymerization initiators. Examples of commercially available cationic polymerization initiators include the "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), the "Cyracure UVI" series (manufactured by Dow Chemical Co., Ltd.), and the "CPI" series (San- Apro Co., Ltd.), "TAZ", "BBI" and "DTS" (the above are manufactured by Midori Kagaku Co., Ltd.), "Adeka Optomer" series (manufactured by ADEKA Co., Ltd.), "RHODORSIL" (registered trademark) ( Manufactured by Rhodia Co., Ltd.), etc. The content of the free radical polymerization initiator and the cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass relative to 100 parts by mass of the active energy ray hardening adhesive.

Active energy ray-hardening adhesives may further include ion trapping agents, antioxidants, chain transfer agents, adhesion-imparting agents, thermoplastic resins, fillers, flow regulators, plasticizers, defoaming agents, etc.

In this specification, active energy rays are defined as energy rays that can decompose compounds that generate active species to generate active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, alpha rays, beta rays, gamma rays, electron beams, etc., and ultraviolet rays and electron beams are preferred. Preferable ultraviolet irradiation conditions are the same as those for polymerization of the above-mentioned polymerizable liquid crystal compound.

[Example]

Hereinafter, the present invention will be described in more detail through examples. "%" and "parts" in the examples refer to mass % and mass parts unless otherwise specified.

The devices, measurement methods, and evaluation methods used in the examples are as follows.

‧Use ZF-14 manufactured by Japan Zeon Co., Ltd. for the cyclic olefin polymer (COP) membrane.

‧Use AGF-B10 manufactured by Kasuga Electric Co., Ltd. for the corona treatment device.

‧Corona treatment is performed once using the above-mentioned corona treatment device at an output of 0.3kW and a treatment speed of 3m/min.

‧For the polarized UV irradiation device, use SPOT CURE SP-7 with a polarizing element unit manufactured by Ushio Electric Co., Ltd.

‧For high-pressure mercury lamps, use QURE VB-15201BY-A manufactured by Ushio Electric Co., Ltd.

‧The in-plane phase difference value was measured using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. Furthermore, the in-plane phase difference values relative to the light with wavelengths of 450nm, 550nm, and 650nm are determined by Calculate the Cauchy dispersion formula obtained from the measurement results.

<Measurement of film thickness>

The film thicknesses of the substrates, photo-alignment films and optically anisotropic films in the examples and comparative examples were measured using an ellipsometer M-220 manufactured by JASCO Corporation.

<Measurement of Haze>

In the examples and comparative examples, the haze of the laminate (2) including the optically anisotropic film was used HAZE METER ("HZ-2" manufactured by Suga Test Instruments Co., Ltd.) was used for measurement.

<Maximum absorption wavelength>

The maximum absorption wavelength of the optically anisotropic film and the polymerizable liquid crystal compound (A) obtained in the Examples was measured using a UV-visible spectrophotometer ("UV-2450" manufactured by Shimadzu Corporation). In addition, the maximum absorption wavelength of the polymerizable liquid crystal compound (A) was measured in chloroform.

<Measurement of organic solvent content (residual amount of organic solvent)>

In the examples and comparative examples, the organic solvent content (remaining amount of organic solvent) in the optically anisotropic film was determined by using TurboMATrix650 manufactured by PerkinElmer as an ATD (Automatic Thermal Desorption) device. The 7890B/5977A MSD manufactured by Agilent is used as a GC/MS (Gas Chromatography-Mass Spectrometer, gas chromatography/mass spectrometer) device, and is measured by thermal desorption gas chromatography mass spectrometry. The optically anisotropic film was heated at 85°C for 48 hours, the generated gas was captured using Tenax porous polymer adsorbent (Tenax TA), and then the captured gas was measured by GC/MS.

<Measurement of phase transition temperature of polymerizable liquid crystal compound (A)>

Measurement was performed using a differential scanning calorimeter ("DSCQ2000" manufactured by TA Instruments). The initial temperature was set to 20°C, the maximum temperature was set to 250°C, and the temperature rising rate was set to 20°C/min.

<Evaluation of orientation>

Using a polarizing microscope (BX51, manufactured by Olympus Co., Ltd.), the laminate (1 ) optically anisotropic film. Those with good alignment were marked as "○", and those with insufficient alignment such as poor alignment observed on the surface were marked as "×".

<Evaluation of panel installation in elliptical polarizers>

The adhesive layer and the optically anisotropic layer were sequentially laminated on the surface of the laminated body (1) obtained in the Examples and Comparative Examples and having the COP (substrate), the optical alignment film and the optical anisotropic film in this order. Polarizing layer to make elliptically polarizing plates. At this time, lamination is performed so that the transmission axis of the polarizing plate is substantially orthogonal to the slow axis of the COP film (base material) of the optically anisotropic film. The obtained elliptically polarizing plate was bonded to the viewing side of Galaxy S5 (registered trademark) (manufactured by Samsung) with the viewing side polarizing plate removed, to produce a liquid crystal display device. Visually confirm the light leakage when displaying black from a direction with an azimuth angle of 45° and an elevation angle of 45° relative to the panel surface.

<Measurement of phase difference value during heat resistance test>

The in-plane phase difference value of the laminated body (2) obtained in the Examples and Comparative Examples with respect to light with a wavelength of 450 nm, a wavelength of 550 nm, and a wavelength of 650 nm was measured. Then, the laminated body (2) was placed in an oven at 85° C. and allowed to pass for 500 hours. After that, the in-plane retardation value was measured, and the amount of change in the in-plane retardation value relative to light with a wavelength of 550 nm before and after the heat resistance test was calculated (heat resistance Changes in the in-plane phase difference relative to light with a wavelength of 550 nm during the test).

[Example 1] (Preparation of composition for forming photo-alignment film)

A composition for forming a photo alignment film (1 ).

Photoalignment materials:

(Preparation of polymerizable liquid crystal composition)

The polymerizable liquid crystal compound (A) of the following structure, a polyacrylate compound (leveling agent) (BYK-361N, manufactured by BYK-Chemie Co., Ltd.), and the following photopolymerization initiator are mixed according to the composition shown below, A polymerizable liquid crystal composition (1) containing a polymerizable liquid crystal compound (A) is obtained.

Polymerizable liquid crystal compound (A):

The polymerizable liquid crystal compound (A) can be synthesized by the method described in Japanese Patent Laid-Open No. 2010-31223 and Japanese Patent Laid-Open No. 2011-207765. The maximum absorption wavelength λ _max (LC) of the polymerizable liquid crystal compound (A) is 350 nm. The polymerizable liquid crystal compound (A) has a liquid crystal phase transition temperature (indicating a nematic phase) of 137°C or higher.

The amount of the polyacrylate compound was set to 0.01 part with respect to 100 parts by mass of the polymerizable liquid crystal compound (A).

The following two types were used as photopolymerization initiators, and the following photopolymerization initiators were added in the following amounts relative to 100 parts by mass of the polymerizable liquid crystal compound (A).

‧Oxime ester type carbazole compound (Yanjiagu OXE-03 (manufactured by BASF Japan Co., Ltd.)): 7.5 parts with respect to 100 parts by mass of the polymerizable liquid crystal compound (A).

‧2-Dimethylamino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one (Irg369 (Irg369), manufactured by BASF Japan Co., Ltd.): relative to The mass of the polymerizable liquid crystal compound (A) is 3 parts per 100 parts.

(Manufacturing of optically anisotropic films)

N-methyl-2-pyrrolidone (NMP) was added to the polymerizable liquid crystal composition (1) so that the solid content concentration became 9%, and the mixture was stirred at 80° C. for 1 hour to obtain a coating liquid. On the other hand, a corona treatment was performed on a cycloolefin polymer (COP) film (film thickness: 23 μm) as a base material using a corona treatment device. Then, use a rod coater to coat the above-mentioned photo-alignment film forming composition (1) on the surface of the COP film (substrate) that has been subjected to corona treatment, dry it at 80° C. for 1 minute, and then use polarized UV The irradiation device performs polarized UV exposure with a cumulative light amount of 100 mJ/cm ² to obtain a photoalignment film. The film thickness of the obtained photo-alignment film was 100 nm.

Then, use a rod coater to coat the above-mentioned coating liquid on the above-mentioned photo-alignment film, dry it at 120° C. for 3 minutes, and then use a high-pressure mercury lamp to irradiate ultraviolet rays from the coating surface side of the coating liquid (under a nitrogen atmosphere, The cumulative light amount at a wavelength of 313 nm is 500 mJ/cm ² ), thereby forming an optically anisotropic film. Thereby, a laminated body (1) having a COP film (base material), a photo-alignment film, and an optically anisotropic film in this order is obtained. The maximum absorption wavelength of the obtained optically anisotropic film was 350 nm, and the film thickness of the optically anisotropic film was 2 μm.

The adhesive layer (adhesive including an acrylic polymer) and the glass substrate are sequentially bonded to the optical anisotropic film of the laminate (1) on the plane perpendicular to the thickness direction and the optical alignment film The surface on the opposite side is then peeled off together with the COP film as the base material and the photo-alignment film. Then, the adhesive layer and the corona-treated COP film (transferred body) are sequentially bonded to the surface. The surface of the optically anisotropic film. Thereby, a laminated body (2) including a glass base material, an adhesive layer, an optically anisotropic film, an adhesive layer, and a COP film (subject) is obtained in this order.

[Example 2]

An optically anisotropic film and a laminated body were obtained in the same manner as in Example 1 except that the drying time was set to 7 minutes.

[Examples 3 and 4]

An optically anisotropic film and a laminated body were obtained in the same manner except that the solvent was cyclopentanone and the drying time was as described in Table 1.

[Examples 5 and 6]

An optically anisotropic film and a laminated body were obtained in the same manner as in Example 1 except that the solvent was γ-butyrolactone (GBL) and the drying time was as described in Table 1.

[Examples 7 and 8]

An optically anisotropic film and a laminated body were obtained in the same manner as in Example 1, except that the solvent was set to propylene glycol monomethyl ether acetate (PGMEA) and the drying time was as described in Table 1.

[Example 9]

An optically anisotropic film and a laminated body were obtained in the same manner as in Example 1 except that the drying temperature was 140° C. and the drying time was 5 minutes. The obtained laminate (1) was used for evaluation of panel mounting in an elliptically polarizing plate. As a result, although thermal wrinkles due to the base material were generated, clear display was obtained.

[Comparative Examples 1~10]

An optically anisotropic film and a laminated body were obtained in the same manner as in Example 1 except that the solvent, drying temperature, and drying time were as described in Table 1.

For the optically anisotropic films and laminates obtained in Examples 1 to 9 and Comparative Examples 1 to 10, the haze, residual solvent amount, and change in in-plane phase difference before and after the heat resistance test were measured and calculated, and, Conduct alignment evaluation and panel installation evaluation of elliptically polarizing plates. The results are shown in Table 1.

The optically anisotropic films obtained in Examples 1 to 9 had relatively little change in phase difference after the heat resistance test and were excellent in heat resistance. Furthermore, it was confirmed that the alignment evaluation was good, the haze was low, and the display was clear in the panel mounting evaluation when used in an elliptically polarizing plate. Therefore, the optically anisotropic films obtained in Examples 1 to 9 have excellent heat resistance, exhibit sufficient alignment, and have excellent optical properties such as low haze. In contrast, it was confirmed that the optically anisotropic films obtained in Comparative Examples 1, 3, 5, and 7 had relatively large retardation changes after the heat resistance test and had low heat resistance. It was confirmed that the polymerizable liquid crystal compound of the optically anisotropic films obtained in Comparative Examples 2, 4, 6 and 8 crystallized, thereby increasing the haze, and when applied to an elliptically polarizing plate, the display showed a whitish display. . It was confirmed that the boiling point of the organic solvent of the optically anisotropic film obtained in Comparative Example 9 was as low as 110°C. Therefore, due to the influence of an insufficient amount of organic solvent in the coating layer during alignment, alignment failure occurred. When applied to elliptical polarizers, the display will appear white. Furthermore, since the drying temperature of the optically anisotropic film obtained in Comparative Example 10 was relatively low, the solvent content was greater than 2000 ppm. In Comparative Example 10, it is believed that the liquid crystal phase transition temperature was not reached in the drying step, and it was confirmed that crystallization occurred without alignment, the haze became high, and when applied to an elliptically polarizing plate, the display of the display became whitish. display.

Claims (5)

An optically anisotropic film, which contains an organic solvent with a boiling point of 120°C or above and a polymer aligned with a polymerizable liquid crystal compound with a liquid crystal phase transition temperature of 120°C or above. The organic solvent with a boiling point of 120°C or above is selected. At least one solvent from the group consisting of free amide solvents, ester solvents, ketone solvents, alcohol solvents, aromatic hydrocarbon solvents and chlorine-containing solvents. The content of organic solvents with a boiling point of 120°C or above is relative to the optical anomaly. The mass of the directional film is 100~2000ppm, and the polymerizable liquid crystal compound is a compound represented by the following formula (I):

[In formula (I), Ar represents a divalent aromatic group which may have a substituent, and the hydrogen atom contained in the divalent aromatic group may be substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. A fluoroalkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, a cyano group or a nitro group, and the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom; G ¹ and G ² independently represent methyl-substituted 1,4-phenylenediyl, unsubstituted 1,4-phenylenediyl, or unsubstituted 1,4-trans-cyclohexane Dibase; L ¹ and L ² independently represent a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-; B ¹ and B ² independently represent a single bond. bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO-, or -OCOCH ₂ CH ₂ -; k and l independently represent integers from 0 to 3, and satisfy The relationship of 1≦k+l, where, in the case of 2≦k+l, B ¹ and B ² and G ¹ and G ² can be the same as each other or different; E ¹ and E ² independently represent the carbon number. 1 to 17 alkanediyl groups, wherein the hydrogen atoms contained in the alkanediyl groups may be substituted by halogen atoms, and the -CH ₂ - contained in the alkanediyl groups may be substituted by -O-, -S-, -Si- Substitution; P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group], and the optically anisotropic film satisfies the following formula (2), formula (3) and formula (4) ): Optical properties represented by: 100nm≦Re(550)≦160nm…(2) Re(450)/Re(550)≦1.0…(3) 1.00≦Re(650)/Re(550)…(4)[ In Formula (2), Formula (3), and Formula (4), Re(450) represents the in-plane phase difference relative to the light with a wavelength of 450 nm, and Re(550) represents the in-plane phase difference relative to the light with a wavelength of 550 nm. value, Re(650) represents the in-plane phase difference value relative to light with a wavelength of 650nm]. For example, the optically anisotropic film of claim 1 has a haze of less than 2%. An elliptically polarizing plate, which includes the optical anisotropic film and polarizing film of claim 1 or 2. A display device comprising the elliptically polarizing plate of claim 3. A method for manufacturing an optically anisotropic film, which is the method for manufacturing an optically anisotropic film according to claim 1 or 2, and includes the following steps: adding an organic solvent with a boiling point of 120°C or above, and a liquid crystal phase transition temperature of 120°C The polymerizable liquid crystal composition of the polymerizable liquid crystal compound above ℃ is coated on the substrate or alignment film to obtain a coating. cloth layer; drying the obtained coating layer at a drying temperature that does not reach the boiling point of the organic solvent and removing the organic solvent from the coating layer, and aligning the polymerizable liquid crystal compound in a liquid crystal state; and by After alignment, the polymerizable liquid crystal compound is polymerized to harden the polymerizable liquid crystal layer to obtain an optically anisotropic film.