WO2014192385A1

WO2014192385A1 - Liquid crystal composition, homeotropically oriented liquid crystal film, polarizing plate, image display device, and method for producing homeotropically oriented liquid crystal film

Info

Publication number: WO2014192385A1
Application number: PCT/JP2014/057749
Authority: WO
Inventors: さなみ矢崎; 松本　卓也; 鈴木　宏明
Original assignee: Ｊｘ日鉱日石エネルギー株式会社
Priority date: 2013-05-31
Filing date: 2014-03-20
Publication date: 2014-12-04
Also published as: TW201510185A; JP2014234412A; JP5655113B2

Abstract

A liquid crystal composition comprising (A) a polymerizable liquid crystal compound, (B) a phosphine compound, (C) a polymerization initiator and (D) a solvent in which the components (A) to (C) can be dissolved.

Description

Liquid crystal composition, homeotropic alignment liquid crystal film, polarizing plate, image display device, and method for producing homeotropic alignment liquid crystal film

The present invention relates to a liquid crystal composition, a homeotropic alignment liquid crystal film, a polarizing plate, an image display device, and a method for producing a homeotropic alignment liquid crystal film.

In image display devices such as liquid crystal displays and organic EL displays, application of liquid crystal films having optical properties such as birefringence (optical anisotropy) is being studied. As such a liquid crystal film, for example, a so-called homeotropic alignment liquid crystal film in which the liquid crystal is aligned perpendicularly to the plane of the film has attracted attention because of its unique optical characteristics. It has been proposed to be applied to applications such as a film for anti-reflection and an anti-reflection film. In recent years, various liquid crystal compositions have been studied in order to efficiently produce such a liquid crystal film.

For example, Japanese Patent Application Laid-Open No. 2008-545856 (Patent Document 1) discloses a liquid crystal composition containing one or more mesogenic or liquid crystal compounds and a polar additive such as a cellulose derivative or a cellulose ester. However, in such a liquid crystal composition as described in Patent Document 1, chemical stability is not always sufficient depending on the kind of polar additive, and workability (mass production efficiency) at the time of manufacturing a liquid crystal film Etc.) is not necessarily sufficient. Japanese Patent Laid-Open No. 2008-543443 (Patent Document 2) discloses a liquid crystal composition comprising a liquid crystal mixture solution containing a surfactant as a material for producing a homeotropic alignment liquid crystal film. However, in such a liquid crystal composition as described in Patent Document 2, when a liquid crystal film is formed on a substrate using this, the adhesion between the substrate and the liquid crystal film is not necessarily sufficient. I couldn't.

JP 2008-545856 A JP 2008-543443 A

The present invention has been made in view of the above-described problems of the prior art, can sufficiently improve the workability during the production of a liquid crystal film, can efficiently produce a homeotropic alignment liquid crystal film, and A liquid crystal composition capable of making the adhesion between the substrate and the homeotropic alignment liquid crystal film sufficiently high when a homeotropic alignment liquid crystal film is produced on the substrate, and a homeo It aims at providing the manufacturing method of a homeotropic alignment liquid crystal film using the tropic alignment liquid crystal film, a polarizing plate, an image display apparatus, and the liquid crystal composition.

As a result of intensive studies to achieve the above object, the inventors of the present invention include a liquid crystal composition containing a polymerizable liquid crystal compound, a phosphine compound, a polymerization initiator, and a solvent capable of dissolving them, When this is used for the production of a liquid crystal film, the workability during the production of the liquid crystal film can be sufficiently improved, the homeotropic alignment liquid crystal film can be efficiently produced, and the homeotropic alignment liquid crystal film is used as the base. It has been found that the adhesion between the substrate and the homeotropic alignment liquid crystal film can be made sufficiently high when manufactured on a material, and the present invention has been completed.

That is, the liquid crystal composition of the present invention comprises (A) a polymerizable liquid crystal compound, (B) a phosphine compound, (C) a polymerization initiator, and (D) a solvent capable of dissolving the components (A) to (C). Is included.

In the liquid crystal composition of the present invention, the phosphine compound has the following general formula (1):

[Wherein R ¹ to R ³ each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 30 carbon atoms, and an optionally substituted aryl group having 6 to 18 carbon atoms. Any one selected from the group consisting of groups is shown. ]
It is preferable that it is at least 1 sort (s) selected from the compound group represented by these. In addition, such a phosphine compound according to the present invention is represented by the general formula (1), and R ¹ to R ³ in the formula may each independently have a substituent. At least one selected from tertiary phosphine, which is any one selected from the group consisting of an alkyl group of ˜30 and an aryl group of 6 to 12 carbon atoms which may have a substituent. More preferably, trimethylphosphine, triethylphosphine, tri-n-butylphosphine, tri-tert-butylphosphine, tri-n-octylphosphine, tricyclohexylphosphine, trishydroxymethylphosphine, trishydroxyethylphosphine, triphenylphosphine , Trismethoxyphenylphosphine and trisethoxyphenylphosphine More preferably, it is at least one selected from the group consisting of tin, trimethylphosphine, triethylphosphine, trishydroxymethylphosphine, trishydroxyethylphosphine, triphenylphosphine, tri-n-butylphosphine, tri-tert- Particularly preferred is at least one selected from the group consisting of butylphosphine, tri-n-octylphosphine, and tricyclohexylphosphine, and most preferred is at least one of trishydroxymethylphosphine and triphenylphosphine. preferable.

In the liquid crystal composition of the present invention, the polymerizable liquid crystal compound is preferably a (meth) acrylate liquid crystal compound.

Furthermore, in the liquid crystal composition of the present invention, the content of the phosphine compound is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

In the liquid crystal composition of the present invention, the content of the polymerization initiator is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

The homeotropic alignment liquid crystal film of the present invention is a homeotropic alignment liquid crystal film that is fixed in a homeotropic alignment state, and is obtained using the liquid crystal composition of the present invention.

The polarizing plate of the present invention is provided with the homeotropic alignment liquid crystal film of the present invention.

Furthermore, an image display device of the present invention includes the polarizing plate of the present invention.

The method for producing a homeotropic alignment liquid crystal film of the present invention includes a step of applying the liquid crystal composition of the present invention on a substrate to form a coating film, and removing the solvent from the coating film to form the polymerizable film. And homeotropic alignment of the liquid crystal compound, followed by polymerizing the polymerizable liquid crystal compound to fix the alignment state, and obtaining a homeotropic alignment liquid crystal film in which the alignment state is fixed in the homeotropic alignment state. Is the method.

In the method for producing a homeotropic alignment liquid crystal film of the present invention, the substrate is preferably a film made of a cyclic olefin polymer.

In the method for producing a homeotropic alignment liquid crystal film of the present invention, the temperature condition for removing the solvent from the coating film is preferably 15 to 110 ° C.

According to the present invention, the workability during the production of the liquid crystal film can be sufficiently improved, the homeotropic alignment liquid crystal film can be efficiently produced, and the homeotropic alignment liquid crystal film is produced on the substrate. A liquid crystal composition capable of making the adhesion between the substrate and the homeotropic alignment liquid crystal film sufficiently high, a homeotropic alignment liquid crystal film obtained using the same, a polarizing plate and an image display device, and It is possible to provide a method for producing a homeotropic alignment liquid crystal film using the liquid crystal composition.

Hereinafter, the present invention will be described in detail on the basis of preferred embodiments thereof.

[Liquid crystal composition]
The liquid crystal composition of the present invention will be described. The liquid crystal composition of the present invention comprises (A) a polymerizable liquid crystal compound, (B) a phosphine compound, (C) a polymerization initiator, and (D) a solvent capable of dissolving the components (A) to (C). It is a waste. Hereinafter, the components (A) to (D) will be described separately.

<Polymerizable liquid crystal compound: component (A)>
Such a polymerizable liquid crystal compound is not particularly limited as long as it is a liquid crystal compound capable of fixing the alignment state by polymerization, and a known polymerizable liquid crystal compound can be appropriately used. In addition, as such a polymerizable liquid crystal compound, it is preferable to use a polymerizable liquid crystal compound that can be homeotropically aligned on a substrate to fix the alignment state. Furthermore, as such a polymerizable liquid crystal compound, for example, a low molecular weight polymerizable liquid crystal compound (a liquid crystalline monomer having a polymerizable group), a high molecular weight polymerizable liquid crystal compound (a liquid crystalline polymer having a polymerizable group), A mixture of these can be used as appropriate.

Moreover, as such a polymerizable liquid crystal compound, a liquid crystal compound having a polymerizable group that reacts with light and / or heat is preferable from the viewpoint that the alignment state can be more efficiently fixed. Such a liquid crystal compound having a polymerizable group that reacts with light or heat can be polymerized with components (liquid crystal compound, etc.) present around it by light and / or heat to fix the alignment. The kind is not specifically limited, A liquid crystal compound provided with a well-known polymeric group can be utilized suitably. Such a polymerizable group is preferably a vinyl group, a (meth) acryloyl group, a vinyloxy group, an oxiranyl group, an oxetanyl group, an aziridinyl group, or the like. As such a polymerizable group, other polymerizable groups such as an isocyanate group, a hydroxyl group, an amino group, an acid anhydride group, and a carboxyl group may be used depending on the reaction conditions.

Furthermore, as such a polymerizable liquid crystal compound, a liquid crystal compound having a (meth) acryloyl group as a polymerizable group is preferable from the viewpoint of availability, heat resistance, and handleability, and a (meth) acrylate liquid crystal compound ( It is more preferable to use (a liquid crystal compound having a (meth) acrylate group). In the present invention, “methacryloyl” and “acryloyl” are sometimes collectively referred to as “(meth) acrylate”, and “methacrylate” and “acrylate” are sometimes collectively referred to as “( “Meth) acrylate”, and in some cases, “methacryl” and “acryl” are collectively referred to as “(meth) acryl”. The “(meth) acrylate group” refers to a residue ((meth) acryloyloxy group) from which hydrogen is eliminated from the carboxylic acid group of (meth) acrylic acid.

Such (meth) acrylate liquid crystal compounds include the following general formulas (10) to (12):

[Wherein, W independently represents any one of H and CH ₃ , n represents an integer of 1 to 20 (more preferably 3 to 6), and Ra represents ^a carbon number of 1 to 20] Any one selected from an alkyl group and an alkoxy group having 1 to 20 carbon atoms, wherein Z ¹ and Z ² are each independently any one of —COO— and —OCO—; X ¹ and X ² each independently represent any of H and an alkyl group having 1 to 7 carbon atoms. ]
The compound represented by these is preferable.

In the general formulas (10) to (12), W independently represents any one of H and CH ₃ . Depending on the type of W, a group represented by CH ₂ = CWCOO in the formula is either an acrylate group or a methacrylate group.

In the general formulas (10) to (12), n is an integer of 1 to 20 (more preferably 2 to 12, more preferably 3 to 6). If the value of n is less than the lower limit, the temperature range in which the compound exhibits liquid crystallinity tends to be small. On the other hand, if the value exceeds the upper limit, the liquid crystal derived from the compound is necessary to achieve good vertical alignment. As a result of the decrease in fluidity, it is difficult to achieve good vertical alignment.

In the general formula (10), R ^a is any group selected from an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 20 carbon atoms. Such an alkyl group having 1 to 20 carbon atoms that can be selected as ^Ra is preferably one having 1 to 12 carbon atoms, and more preferably 3 to 6 carbon atoms. When the number of carbons exceeds the upper limit, the fluidity derived from the liquid crystal of the compound necessary for realizing good vertical alignment becomes small, and as a result, it becomes difficult to realize good vertical alignment. Moreover, when the carbon number is less than the lower limit, the temperature range in which the compound exhibits liquid crystallinity tends to be small. Such an alkyl group may be linear, branched, or cyclic, and is not particularly limited. Is more preferably linear.

In addition, the alkoxy group having 1 to 20 carbon atoms that can be selected as ^Ra is preferably one having 1 to 12 carbon atoms, and more preferably 3 to 6 carbon atoms. When the number of carbons exceeds the upper limit, the fluidity derived from the liquid crystal of the compound necessary for realizing good vertical alignment becomes small, and as a result, it becomes difficult to realize good vertical alignment. Moreover, when the carbon number is less than the lower limit, the temperature range in which the compound exhibits liquid crystallinity tends to be small. The alkoxy group has a structure in which an alkyl group is bonded to an oxygen atom. The structure of the alkyl group portion may be linear, branched, or cyclic. Although it may be sufficient and it does not restrict | limit, From a viewpoint of implement | achieving favorable vertical alignment, it is more preferable that it is a linear thing.

In the general formula (12), Z ¹ and Z ² are each independently any group of —COO— and —OCO—. Such Z ¹ and Z ² are groups in which ^one of Z ¹ and Z ² is represented by —COO—, and the other group is — A group represented by OCO- is preferred.

In the general formula (12), X ¹ and X ² each independently represent any of H and an alkyl group having 1 to 7 carbon atoms. The alkyl group having 1 to 7 carbon atoms which can be selected as X ¹ and X ² is more preferably 1 to 3 carbon atoms (the alkyl group is CH ₃ ). Is more preferable. If the number of carbon atoms exceeds the above upper limit, it tends to be difficult to achieve good vertical alignment. Thus, it is particularly preferable that X ¹ and X ² are each independently one of H and CH ₃ .

Further, as the (meth) acrylate liquid crystal compounds represented by the general formulas (10) to (12), for example, the following general formulas (110) to (113):

And the compounds as described above. Such (meth) acrylate liquid crystal compounds may be used singly or in combination of two or more.

Further, as the polymerizable liquid crystal compound, it is preferable to use a combination of the compounds represented by the general formulas (10) to (12), and a combination of the compounds represented by the general formulas (110) to (113). It is more preferable to use it.

As described above, when the compounds represented by the general formulas (10) to (12) are used in combination as the polymerizable liquid crystal compound, the content of the compound represented by the general formula (10) The amount is preferably 20 to 60% by mass, more preferably 30 to 45% by mass, based on the total amount of the compounds represented by formulas (10) to (12). When the content of the compound represented by the general formula (10) is less than the lower limit, an alignment defect tends to occur with respect to the vertical alignment, and when the content exceeds the upper limit, an alignment defect tends to occur with respect to the vertical alignment. It is in.

In the case where the compounds represented by the general formulas (10) to (12) are used in combination, the content of the compound represented by the general formula (11) is represented by the general formulas (10) to (12). The amount is preferably 10 to 50% by mass, more preferably 20 to 30% by mass, based on the total amount of the compounds represented. When the content of the compound represented by the general formula (11) is less than the lower limit, an orientation defect tends to occur with respect to the vertical alignment. On the other hand, when the content exceeds the upper limit, an orientation defect tends to occur with respect to the vertical orientation. It is in.

Further, when the compounds represented by the general formulas (10) to (12) are used in combination, the content of the compound represented by the general formula (12) is represented by the general formulas (10) to (12). The amount is preferably 10 to 70% by mass, more preferably 25 to 45% by mass, based on the total amount of the compounds represented. When the content of the compound represented by the general formula (12) is less than the lower limit, an alignment defect tends to occur with respect to the vertical alignment, and when it exceeds the upper limit, an alignment defect tends to occur with respect to the vertical alignment. It is in.

Furthermore, when the compounds represented by the general formulas (110) to (113) are used in combination as the polymerizable liquid crystal compound, the mass ratio of each compound is ([ Compound Represented by General Formula (110)]: [Compound Represented by General Formula (111)]: [Compound Represented by General Formula (112)]: [Compound Represented by General Formula (113)]) Is preferably 45: 40: 15: 0 to 35: 5: 30: 30, and more preferably 35: 23: 23: 19 to 38: 25: 25: 12.

Further, the method for producing such a polymerizable liquid crystal compound is not particularly limited, and a known method can be appropriately used. For example, in the case of producing a compound represented by the general formula (110), For example, the method described in British Patent Application Publication No. 2,280,445 (GB2,280,445) may be adopted, and when the compound represented by the above general formula (111) is produced, For example, D.D. J. et al. The method described on pages 3201 to 3215 of “Makromol. Chem. (Vol. 190, published in 1989)” by Broer et al. May be employed and is represented by the above general formulas (112) to (113). For example, a method described in International Publication No. 93/22397 may be employed. Thus, the polymerizable liquid crystal compound can be produced by appropriately using a known method according to the type of the compound to be used. Moreover, you may utilize a commercial item as such a polymeric liquid crystal compound. Further, such polymerizable liquid crystal compounds may be used alone or in combination of two or more.

Such a polymerizable liquid crystal compound may use a mixture of a liquid crystal compound having a polymerizable group and another polymerizable monomer that does not exhibit liquid crystallinity. As such other polymerizable monomers, in particular, they have compatibility with a liquid crystal compound having a polymerizable group and are not particularly likely to cause alignment inhibition when orienting the liquid crystal compound. It is not limited, A well-known polymerizable monomer can be utilized suitably, What is necessary is just to select and use a suitable monomer from well-known polymerizable monomers according to the design of the target liquid crystal composition. Examples of such other polymerizable monomers include compounds having a polymerizable functional group such as an ethylenically unsaturated group (for example, vinyl group, vinyloxy group, (meth) acryloyl group). The addition amount of such other polymerizable monomer is 0.5 to 50% by mass based on the total amount of the liquid crystal compound having a polymerizable group and the other polymerizable monomer not exhibiting liquid crystallinity. The content is preferably 1 to 30% by mass. Further, the number of polymerizable functional groups of such a polymerizable monomer is preferably 2 or more from the viewpoint of sufficiently increasing the polymerization rate and imparting sufficient heat resistance to the obtained liquid crystal film. . Furthermore, the method for producing such a polymerizable monomer is not particularly limited, and a known method can be appropriately used. Moreover, you may utilize a commercial item as such a polymerizable monomer.

<Phosphine compound: component (B)>
In the phosphine compound according to the present invention, phosphine (PH ₃ ) and at least one hydrogen atom in the phosphine are an alkyl group which may have a substituent or an aryl group which may have a substituent. At least one compound selected from the group consisting of substituted compounds (primary to tertiary phosphines). By including such a phosphine compound in the liquid crystal composition, the reason for this is not necessarily clear, but it may be a base material such as a base material on which an alignment film is not formed, regardless of the type of base material. ), When the solvent is removed after the liquid crystal composition is applied to the substrate, the alignment state of the polymerizable liquid crystal compound can be aligned in the homeotropic alignment state. Thus, by using the phosphine compound together with the polymerizable liquid crystal compound in the liquid crystal composition, the polymerizable liquid crystal compound is efficiently obtained by performing a simple process of removing the solvent from the liquid crystal composition. Homeotropic alignment is possible. When the phosphine compound is contained in the liquid crystal composition, the homeotropic alignment can be formed in a sufficiently short time depending on the type of the polymerizable liquid crystal compound or the solvent in the composition. Become. In addition, since such a phosphine compound is not an unstable compound whose reaction is difficult to control, but a chemically sufficiently stable compound, a liquid crystal film or the like can be obtained using a liquid crystal composition containing the component. When manufacturing, the working efficiency can be made sufficiently high. Therefore, in the liquid crystal composition of the present invention using such a phosphine compound, there is no need to provide a special control facility for controlling the reaction, and a simple process such as removing the solvent can be performed in a sufficiently short time. An alignment can be formed, and as a result, a homeotropic alignment liquid crystal film can be produced more efficiently. Further, such a phosphine compound can sufficiently suppress a decrease in adhesion between the base material and the liquid crystal film as compared with a so-called surfactant, and thus the liquid crystal composition of the present invention. When the homeotropic alignment liquid crystal film is produced on the base material using the adhesive, the adhesion between the base material and the homeotropic alignment liquid crystal film can be made sufficiently high.

Such phosphine compounds include the following general formula (1):

[Wherein R ¹ to R ³ each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 30 carbon atoms, and an optionally substituted aryl group having 6 to 18 carbon atoms. Any one selected from the group consisting of groups is shown. ]
At least one selected from the group of compounds represented by

The alkyl group which may have a substituent and can be selected as R ¹ to R ³ in the general formula (1) has 1 to 30 carbon atoms as described above. The number of carbon atoms of the alkyl group which may have such a substituent is more preferably 1 to 20, further preferably 1 to 10, and particularly preferably 1 to 5. When the carbon number of such an alkyl group exceeds the upper limit, the compatibility with the liquid crystal compound is lowered and the vertical alignment tends to be inhibited. Such an alkyl group may be linear or branched, and includes, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, It may be a t-butyl group or the like.

Further, the alkyl group that can be selected as the R ¹ to R ³ may have a substituent as described above. Such a substituent is not particularly limited and includes, for example, a halogen atom, a hydroxyl group, a carboxyl group and a salt thereof, an alkoxy group, a sulfo group and a salt thereof, among others, from the viewpoint of chemical stability, A hydroxyl group and an alkoxy group are preferred, and a hydroxyl group is more preferred.

As the alkyl group having 1 to 30 carbon atoms which may have such a substituent, from the viewpoint of chemical stability, a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, t- A butyl group, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a methoxymethyl group, an ethoxymethyl group, and a methoxyethyl group are preferable, and a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group are preferable. More preferred are a hydroxymethyl group and a hydroxyethyl group.

In addition, as described above, the aryl group which may have a substituent which can be selected as R ¹ to R ³ in the general formula (1) has 6 to 18 carbon atoms. The aryl group which may have such a substituent preferably has 6 to 12 carbon atoms, more preferably 6 to 9 carbon atoms. When the number of carbon atoms in the aryl group exceeds the upper limit, the compatibility with the liquid crystal compound is lowered and the vertical alignment tends to be inhibited.

In addition, the aryl group that can be selected as the R ¹ to R ³ may have a substituent as described above. Such a substituent is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkoxy group, and a halogenated alkyl group. Among these substituents, among these, from the viewpoint of compatibility with the liquid crystal compound, a halogen atom, an alkyl group having 1 to 4 carbon atoms (more preferably 1 to 2), and 1 to 4 carbon atoms (more preferably 1 carbon atom). To 2) an alkoxy group, and a halogenated alkyl group having 1 to 4 (more preferably 1 to 2) carbon atoms are more preferred.

Examples of the aryl group having 6 to 18 carbon atoms which may have such a substituent include, for example, phenyl group, tolyl group, xylyl group, cumenyl group, methoxyphenyl group, sulfophenyl group, halogenated phenyl group, A carboxyphenyl group etc. are mentioned, Among these, a phenyl group and a methoxyphenyl group are preferable from a compatible viewpoint with a liquid crystal compound, and a phenyl group is especially preferable.

Further, the phosphine compound is preferably a primary to tertiary phosphine from the viewpoint of adhesion between the substrate and the liquid crystal film, promotion of vertical alignment, etc., and secondary to tertiary phosphine. Is more preferable, and tertiary phosphine is particularly preferable. Further, when the phosphine compound is a compound represented by the general formula (1), at least one of R ¹ to R ³ is a group other than a hydrogen atom (having 1 to 1 carbon atoms which may have a substituent). 30 alkyl groups and any one selected from the group consisting of aryl groups having 6 to 18 carbon atoms (more preferably 6 to 12 carbon atoms) which may have a substituent (the phosphine compound is Primary to tertiary phosphine) is preferred, and at least two of R ¹ to R ³ are groups other than hydrogen atoms (the phosphine compound is a secondary to tertiary phosphine). It is more preferable that R ¹ to R ³ are all groups other than hydrogen atoms (the phosphine compound is a tertiary phosphine).

In addition, the phosphine compound according to the present invention is represented by the general formula (1) from the viewpoint of adhesion between the base material and the liquid crystal film, promotion of vertical alignment, and compatibility with the polymerizable liquid crystal compound, and In the formula, R ¹ to R ³ each independently represents an alkyl group having 1 to 30 carbon atoms which may have the above substituent and an aryl group having 6 to 12 carbon atoms which may have the above substituent. More preferably, it is at least one selected from among tertiary phosphines that are any one selected from the group consisting of:

Such phosphine compounds include trimethylphosphine, triethylphosphine, tributylphosphine (more preferably tri-n-butylphosphine, tri-tert-butyl) from the viewpoint of easy availability and compatibility with polymerizable liquid crystal compounds. Phosphine), tri-n-octylphosphine, tricyclohexylphosphine, trishydroxymethylphosphine, trishydroxyethylphosphine, triphenylphosphine, trismethoxyphenylphosphine, trisethoxyphenylphosphine, trimethylphosphine, triethylphosphine, tri-n- Butylphosphine, tri-tert-butylphosphine, tri-n-octylphosphine, tricyclohexylphosphine, trishydroxymethylphosphine, Lishydroxyethylphosphine, triphenylphosphine, trismethoxyphenylphosphine, and trisethoxyphenylphosphine are more preferable. Trimethylphosphine, triethylphosphine, trishydroxymethylphosphine, trishydroxyethylphosphine, triphenylphosphine, tri-n-butylphosphine, tris -Tert-butylphosphine, tri-n-octylphosphine, and tricyclohexylphosphine are more preferable, and trishydroxymethylphosphine and triphenylphosphine are particularly preferable. In addition, such a phosphine compound may be used individually by 1 type, or may be used in combination of 2 or more type. Moreover, it does not restrict | limit especially as a method for manufacturing such a phosphine compound, A well-known method is employable suitably. Moreover, you may utilize a commercial item for such a phosphine compound.

<Polymerization initiator: (C) component>
Such a polymerization initiator is not particularly limited, and a known polymerization initiator can be appropriately used. As described above, the polymerization initiator can start the polymerization of the polymerizable liquid crystal compound more efficiently according to the type of the polymerizable liquid crystal compound in the composition from among known polymerization initiators. What is necessary is just to select suitably and use.

Moreover, even if such a polymerization initiator is a thermal polymerization initiator (an initiator when utilizing a thermal polymerization reaction), a photopolymerization initiator (an initiator when utilizing light or electron beam irradiation) It may be. As such a polymerization initiator, in the case of using a plastic film or the like as a base material when producing a liquid crystal film, from the viewpoint of preventing the base material and the like from being deformed or altered by heat, It is more preferable to use a photopolymerization initiator. Examples of such photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and triarylimidazole dimers and p-aminophenyl ketones. And acridine and phenazine compounds and oxadiazole compounds. Examples of such α-carbonyl compounds include α-carbonyl compounds described in US Pat. No. 2,367,661 and US Pat. No. 2,367,670. Examples of the acyloin ether include US Pat. The thing etc. which are described in 2448828 specification are mentioned. Examples of the α-hydrocarbon-substituted aromatic acyloin compound include those described in US Pat. No. 2,722,512. Examples of the polynuclear quinone compound include US Pat. No. 3,046,127 and US Pat. No. 2,951,758. And the like described in the specification. Examples of the combination of triarylimidazole dimer and p-aminophenyl ketone include those described in US Pat. No. 3,549,367. Examples of the acridine and phenazine compound include, for example, Examples described in JP-A-60-105667, US Pat. No. 4,239,850 and the like, and examples of the oxadiazole compound include those described in US Pat. No. 4,212,970. .

Further, as such a photopolymerization initiator, a commercially available product may be used. For example, a photopolymerization initiator (trade name “Irgacure 907”, trade name “Irgacure 651”, trade name, manufactured by Ciba-Geigy) “Irgacure 184”), a photopolymerization initiator (trade name “UVI6974”) manufactured by Union Carbide, Inc. may be used as appropriate. Such photopolymerization initiators include those that generate free radicals and those that generate ions upon irradiation with light or an electron beam, and the type and polymerization of the polymerizable liquid crystal compound in the composition. A photopolymerization initiator that generates free radicals (for example, “Irgacure 651” manufactured by Ciba-Geigy) or a photopolymerization initiator that generates ions (for example, Union Carbide, Inc.) depending on the reaction conditions. A suitable photopolymerization initiator (trade name “UVI6974”) manufactured by the company may be appropriately selected and used.

<Solvent: Component (D)>
Such a solvent is capable of dissolving the components (A) to (C) (for dissolving). By including such a solvent in the composition, each component is uniformly dissolved in the solvent, and a more uniform liquid crystal alignment film is obtained when a liquid crystal film is produced using such a composition.

Further, such a solvent is not particularly limited, and a known solvent that can be used for the liquid crystal composition can be appropriately used. Examples of such solvents include heterocyclic rings such as tetrahydrofuran, γ-butyrolactone, and N-methylpyrrolidone; glycol derivatives such as 2-methoxyethyl acetate, propylene glycol 1-monomethyl ether 2-acetate; chloroform, dichloromethane, tetra Halogenated hydrocarbons such as chloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene; aromatic hydrocarbons such as benzene, toluene, zylene, methoxybenzene, 1,2-dimethoxybenzene; acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone Ketones such as isopropyl alcohol and n-butanol; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; and the like.

In addition, as such a solvent, from the viewpoint of drying speed suitable for applying the solution so as to obtain a uniform film thickness, ease of handling (harmful to the environment) and solubility in the polymerizable liquid crystal compound, Propylene glycol 1-monomethyl ether 2-acetate, 2-methoxyethyl acetate, toluene, xylen, methoxybenzene, 1,2-methoxybenzene, cyclohexanone, cyclopentanone, methyl cellosolve, ethyl cellosolve, butyl cellosolve, γ-butyrolactone are preferred, Propylene glycol 1-monomethyl ether 2-acetate and γ-butyrolactone are more preferred. In addition, you may utilize 1 type as such a solvent individually or in combination of 2 or more types. In addition, depending on the type of base material, corrosion may occur depending on the type of solvent. Therefore, it is preferable to select and use a suitable solvent according to the type of base material.

The components (A) to (D) contained in the liquid crystal composition of the present invention have been described above separately. Hereinafter, the liquid crystal composition of the present invention containing these components will be described. The liquid crystal composition of the present invention containing the components (A) to (D) is applied to a substrate and then the solvent is removed to remove the alignment state of the polymerizable liquid crystal compound (component (A)). Can be brought into a homeotropic alignment state, and this is polymerized to fix the alignment state, whereby a homeotropic alignment liquid crystal film can be efficiently produced. Therefore, according to the liquid crystal composition of the present invention, it is possible to produce a homeotropic alignment liquid crystal film by a simple process such as application of the composition, removal of a solvent, and immobilization. It is particularly useful as a material used for typical production.

The liquid crystal composition of the present invention contains components (A) to (D). The content of the phosphine compound (component (B)) in the liquid crystal composition of the present invention is 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound (component (A)). It is preferably 1 to 5 parts by mass. When the content of such a phosphine compound is less than the above lower limit, the time required for vertical alignment becomes longer during the production of homeotropic alignment liquid crystal film, or at the film stage before immobilization (such as drying the solvent from the composition). When the above upper limit is exceeded, the adhesion between the substrate and the liquid crystal film (adhesive strength of the liquid crystal film) tends to occur. Tend to decrease.

In addition, the content (component (C)) of the polymerization initiator in the liquid crystal composition of the present invention is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. More preferably, it is part by mass. If the content of the polymerization initiator is less than the lower limit, the resulting liquid crystal film tends to have insufficient curability. On the other hand, if the content exceeds the upper limit, defects tend to occur in the vertical alignment of the liquid crystal.

In addition, the content of the solvent in the liquid crystal composition of the present invention is the use method of the composition (for example, when used to form a liquid crystal film, including the design of the thickness, the coating method, etc.) Depending on the method and the like, and cannot be generally described, but is preferably 30 to 98% by mass, more preferably 50 to 95% by mass, and 70 to 90% by mass. More preferred is 80 to 90% by mass. If the content of the solvent is less than the lower limit, the amount of the solvent with respect to the total amount of the components (A) to (C) decreases, so that liquid crystal is deposited during storage or the viscosity of the liquid crystal composition increases. Since the wettability of the liquid crystal film is reduced, it tends to be difficult to coat the liquid crystal film. On the other hand, if the upper limit is exceeded, the removal time (drying time) takes longer when the solvent is removed. When the film is manufactured, not only the working efficiency is lowered, but also when the liquid crystal composition is coated on the substrate, the flow of the surface becomes intense, so that the composition can be used to produce a uniform liquid crystal film. It tends to be difficult. Thus, in the liquid crystal composition of the present invention, the total amount of the components (A) to (C) (the amount of the mixture of components other than the solvent) is based on the total amount of the components (A) to (D). , Preferably 5 to 70% by mass, more preferably 10 to 50% by mass, still more preferably 10 to 30% by mass, and particularly preferably 10 to 20% by mass. .

Further, in the liquid crystal composition of the present invention, the reaction activator, sensitizer, antifoaming agent, and the like, depending on the type of each component contained in the liquid crystal composition, as long as the effect is not impaired. You may add a leveling agent etc. suitably.

Further, the method for producing such a liquid crystal composition of the present invention is not particularly limited, and a method capable of obtaining a liquid crystal composition containing the components (A) to (D) can be appropriately used. For example, a method of adding the components (A) to (C) to the component (D) and mixing them to obtain a liquid crystal composition may be used. In addition, when such a method is adopted and the components (A) to (C) are added to the component (D) and mixed, the order of adding the components is not particularly limited, and the ( Each component may be appropriately added so that the components A) to (C) can be dissolved in the component (D). For example, the components (A) to (C) are sequentially added to the component (D). A method of adding (in no particular order), a method of adding component (C) after adding a mixture of components (A) to (B) in component (D), component (A) and component (C) in component (D) A method of adding the component (B) after adding the mixture of the component (A), a method of adding the mixture of the components (A) to (C) to the component (D), etc. may be appropriately employed.

Further, as described above, the liquid crystal composition of the present invention is used as a material for producing a liquid crystal film in which the alignment state is fixed in a homeotropic alignment state (hereinafter simply referred to as “homeotropic alignment liquid crystal film”). It can be suitably used. As such a homeotropic alignment liquid crystal film, it is preferable that it was obtained using the manufacturing method of the homeotropic alignment liquid crystal film of this invention mentioned later.

[Homeotropic alignment liquid crystal film]
The homeotropic alignment liquid crystal film of the present invention is a homeotropic alignment liquid crystal film that is fixed in a homeotropic alignment state, and is obtained using the liquid crystal composition of the present invention.

Such homeotropic alignment liquid crystal film is not particularly limited as long as it is a liquid crystal film obtained by fixing the alignment state in a homeotropic alignment state using the liquid crystal composition of the present invention. The liquid crystal composition of the present invention is applied to form a coating film, the solvent is removed from the coating film and the polymerizable liquid crystal compound is homeotropically aligned, and then the polymerizable liquid crystal compound is polymerized. A homeotropic alignment liquid crystal film obtained by fixing the alignment state is preferable. In addition, as described above, the liquid crystal composition of the present invention is capable of changing the alignment state of the polymerizable liquid crystal compound into a homeotropic alignment state by removing the solvent after coating, and is simple. In addition, a homeotropic alignment liquid crystal film can be produced.

Here, the state that “the alignment state is fixed in a homeotropic alignment state” is a homeotropic alignment (so-called vertical alignment) in a liquid crystal film obtained after polymerizing the polymerizable liquid crystal compound to fix the alignment. : Alignment in which the major axis direction of the liquid crystal molecules is aligned in a direction substantially perpendicular to the substrate) is derived from the polymerizable liquid crystal compound and the like contained in the liquid crystal composition Among the components (preferably a component derived from the polymerizable liquid crystal compound: the polymerizable liquid crystal compound itself, a composition formed by decomposing the polymerizable liquid crystal compound, a polymer of the polymerizable liquid crystal compound, and the like). Any of these may be fixed in a homeotropic alignment state.

In addition, as a method for confirming homeotropic alignment in such a liquid crystal film, the following method may be employed. As a method for confirming such homeotropic alignment, a known method can be appropriately employed, and is not particularly limited. However, a pair of orthogonal polarizing plates (a direction in which one deflecting plate is deflected and a direction in which the other deflecting plate is Using a sample in which a liquid crystal film (which may be in the form of a laminate with a base material) is disposed between a pair of polarizing plates whose deflection directions are perpendicular to each other, the transmitted light is confirmed with the naked eye. And a method of observing the liquid crystal film with a polarizing microscope may be employed. In any of the above methods, when the liquid crystal film is a homeotropic alignment liquid crystal film, the light phase difference is obtained when light is incident from a direction perpendicular to the surface of the liquid crystal film in the sample. The sample appears black because the light cannot pass through the sample. On the other hand, if the incident angle of the light incident on the sample is tilted, a phase difference occurs and the light is transmitted, and the sample appears bright. . Therefore, the presence or absence of homeotropic orientation can be confirmed by measuring the brightness of such a sample through the naked eye or a polarizing microscope while shifting the incident angle of light. In addition, since the homeotropic alignment liquid crystal film has different phase difference characteristics depending on the incident angle of light as described above, a method for confirming the homeotropic alignment is, for example, on the surface of the liquid crystal film. A birefringence measuring apparatus (for example, an axo-matrix) capable of measuring a phase difference in a vertical direction (perpendicular incident angle) and a phase difference when the incident angle of light is tilted from the vertical incident angle to a specific angle. The viewing angle becomes larger from 0 ° viewing angle (perpendicular to the liquid crystal film) using the product name “axoscan” manufactured by Nihon Oji Co., Ltd. and the product name “KOBRA-21ADH” manufactured by Nippon Oji Scientific Instruments. Measure the phase difference while changing the angle appropriately, determine the phase difference of the sample at multiple viewing angles, and position it in the direction perpendicular to the surface of the liquid crystal film. The difference is not confirmed, the phase difference becomes larger in the direction in which the viewing angle becomes larger with respect to the surface of the liquid crystal film, and the values of the − direction and the + direction of the viewing angle show symmetry with each other. A method of confirming the presence or absence of homeotropic alignment may be employed based on the confirmation.

The thickness of such a liquid crystal film (thickness of the cured film of the liquid crystal composition) is preferably 0.1 to 10 μm, although it varies depending on the application and required characteristics, and is preferably 0.2 to It is more preferably 5 μm, and further preferably 0.3 to 2 μm. If the thickness of such a liquid crystal film is less than the lower limit, a desired retardation may not be exhibited. On the other hand, if the thickness exceeds the upper limit, the orientation of the liquid crystal tends to decrease.

In addition, the liquid crystal film may be required to have a specific retardation value as well as a film thickness depending on its use. Here, the refractive index in the direction indicating the maximum refractive index direction in the plane of the liquid crystal film is Nx, the refractive index in the direction perpendicular thereto is Ny, the refractive index in the thickness direction is Nz, and the thickness of the liquid crystal film is d (nm). ), The refractive index relationship of the homeotropic alignment liquid crystal film is usually Nz> Nx ≧ Ny. The in-plane retardation value (Re = (Nx−Ny) × d [nm]) of such homeotropic alignment liquid crystal film is preferably 0 nm to 20 nm (more preferably 0 nm to 10 nm), The retardation value in the vertical direction (Rth = {(Nx + Ny) / 2−Nz} × d [nm]) is preferably 80 nm to 200 nm (more preferably 130 nm to 170 nm). Such Re and Rth are values for light having a wavelength of 550 nm. As such retardation value, an apparatus capable of measuring birefringence (for example, a trade name “axoscan” manufactured by axo-matrix, a product name “KOBRA-21ADH” manufactured by Nippon Oji Scientific Instruments), etc.) is used. The value measured by using can be adopted.

Further, such homeotropic alignment liquid crystal film has a sufficiently high adhesion to the base material when manufactured by applying the liquid crystal composition of the present invention on the base material. And can be suitably used as an optical film or the like. In addition, about such a base material, it demonstrates in detail in the manufacturing method of the homeotropic alignment liquid crystal film of this invention mentioned later.

[Method for producing homeotropic alignment liquid crystal film]
The method for producing a homeotropic alignment liquid crystal film of the present invention includes a step of applying the liquid crystal composition of the present invention on a substrate to form a coating film (step (A)), and removing the solvent from the coating film. After the homeotropic alignment of the polymerizable liquid crystal compound, the alignment state is fixed by polymerizing the polymerizable liquid crystal compound to obtain a homeotropic alignment liquid crystal film in which the alignment state is fixed in the homeotropic alignment state. A step (step (B)). Hereinafter, each process will be described separately.

Step (A) is a step of forming a coating film by applying the liquid crystal composition of the present invention on a substrate. Such a substrate is not particularly limited as long as it can be used for an optical film, and a known substrate for an optical film can be appropriately used. Examples of such a base material include a base material made of an organic polymer material and a base material made of an inorganic material (for example, a glass plate, a metal plate, a film formed from a metal such as aluminum). .

Such a substrate is optically isotropic from the viewpoint of maintaining optical properties as an optical film when a laminate of the substrate and the homeotropic alignment liquid crystal film is used as an optical film for a liquid crystal display or the like. Those having high properties and light transmittance of 80% or more can be suitably used. Moreover, as such a base material, it is preferable to use the base material which consists of organic polymer materials from a viewpoint of cost or continuous productivity. Examples of such an organic polymer material (polymer) include polyvinyl alcohol, polyimide, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether ketone, polyether sulfone, polyether ether ketone, polyarylate, polyethylene terephthalate, and polyethylene naphthalate. Polyester polymers such as: Cellulose polymers such as diacetyl cellulose and triacetyl cellulose; Polycarbonate polymers; Transparent polymers such as (meth) acrylic polymers such as polymethyl (meth) acrylate; Polystyrene, acrylonitrile / styrene copolymers, etc. Styrene polymers; Olefin polymers such as polyethylene, polypropylene, and ethylene / propylene copolymers; nobornene derivatives Cyclic olefin polymer (polycycloolefin); amide polymers such as nylon and aromatic polyamide; vinyl chloride polymer polymer materials and blends thereof of the like. “Cyclic olefin polymer” is a general generic name for resins obtained from cyclic olefins such as norbornene, dicyclopentadiene, tetracyclododecene and derivatives thereof. In addition, as the organic polymer material as the material of such a base material, it is possible to exhibit characteristics (for example, transparency) suitable for an optical film, and therefore, a cellulose polymer, a polycarbonate polymer, a cyclic polymer, and the like. An olefin polymer (cycloolefin polymer: COP) is more preferable.

As such a cellulose polymer, a lower fatty acid ester of cellulose is more preferable. As such a lower fatty acid, a fatty acid having 6 or less carbon atoms is preferable. Further, the number of carbon atoms of such a lower fatty acid is more preferably 2-4. Examples of such a cellulose polymer include cellulose acetate, cellulose propionate, and cellulose butyrate. Among such cellulose polymers, cellulose triacetate is particularly preferable. As the cellulose polymer, a mixed fatty acid ester such as cellulose acetate propionate or cellulose acetate butyrate may be used.

Examples of the cyclic olefin polymer (COP) include cyclic olefin ring-opening polymers, cyclic olefin addition polymers, random copolymers of cyclic olefins and α-olefins such as ethylene and propylene, and the like. Examples include graft-modified products modified with saturated carboxylic acid and derivatives thereof, and hydrides thereof. Moreover, as such a cyclic olefin, norbornene, its derivative (s), and dicyclopentadiene are preferable.

Moreover, as a base material made of such an organic polymer material, a film made of triacetyl cellulose, polycarbonate, a cyclic olefin polymer (cycloolefin polymer: COP) is highly transparent and easily available. A base material (plastic film) is more preferable. In addition, among such film-like substrates (plastic films), when the liquid crystal composition contains a (meth) acrylate-based liquid crystal compound, it is possible to impart sufficiently high adhesion. Is particularly preferably a film made of a cyclic olefin polymer (hereinafter sometimes referred to as “COP film”).

Further, commercially available products may be used as appropriate for such base materials. For example, when a COP film is used as the base material, trade names “ZEONEX” manufactured by ZEON CORPORATION, trade names manufactured by ZEON CORPORATION "Zeonor", JSR Corporation product name "Arton", Sekisui Chemical Co., Ltd. product name "Essina", Topas Advanced Polymers GmbH product name "Topas", Mitsui Chemicals Co., Ltd. product name "Apel" Or the like can be used as appropriate.

In addition, such a substrate is not particularly limited, but in the case of using the formed laminate of the liquid crystal film and the substrate as it is for an optical film or the like, depending on the application, etc. It may have a phase difference function. Further, such a substrate may be uniaxially stretched (so-called uniaxially stretched film) or biaxially stretched (so-called biaxially stretched film). Such a base material may be used as a film having optical anisotropy by developing biaxial optical anisotropy by stretching the base material in the vertical direction and the horizontal direction.

Further, as such a base material, a substrate that has been subjected to a Z-axis orientation treatment may be used. Further, such a substrate may be appropriately subjected to surface treatment such as corona treatment, plasma treatment, UV-ozone treatment, saponification treatment on one or both sides for the purpose of controlling the adhesion. The treatment conditions for adopting such a surface treatment may be appropriately set according to the base material to be used, and are not particularly limited, and known conditions may be appropriately adopted. In the present invention, the polymerizable liquid crystal compound in the coating film is formed by coating the liquid crystal composition of the present invention on the substrate to form a coating film, and then removing the solvent from the coating film. Can be aligned in a homeotropic alignment state, it is not always necessary to form an alignment film on the substrate, and in this case, the alignment film forming step can be shortened. . And, when the alignment film is not formed in this way, the base material can be used without calculating the thickness of the alignment film, so the base material design (characteristics, thickness, etc.) can be made more efficient depending on the application. It is possible to change.

In the step (A), the method for applying the liquid crystal composition of the present invention on the substrate is not particularly limited, and a known method can be appropriately employed. As such a coating method, for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, a spin coating method, or the like can be appropriately employed.

Thus, a coating film can be obtained by applying the liquid crystal composition of the present invention on the substrate. Such a coating film is different depending on the content of the solvent in the liquid crystal composition of the present invention and cannot be generally described. However, the thickness of the coating film (wet film thickness) before drying is 3 It is preferably ˜50 μm, more preferably 5 to 20 μm. If such a thickness (wet film thickness) is less than the lower limit, it is necessary to increase the concentration of solid content (liquid crystal compound, etc.) in the liquid crystal composition in order to obtain desired optical characteristics. In addition to the difficulty of obtaining a uniform liquid crystal film due to the occurrence of minute precipitation, uniform coating is difficult and the smoothness of the liquid crystal film tends to decrease. Since the concentration of the solid content in the liquid crystal composition for obtaining the characteristics is thin, the drying time after coating tends to be long.

The process (A) has been described above, but the process (B) will be described below. In step (B), the solvent is removed from the coating film, and the polymerizable liquid crystal compound (component (A) in the liquid crystal composition) is homeotropically aligned, and then the polymerizable liquid crystal compound is polymerized for alignment. This is a step of obtaining a homeotropic alignment liquid crystal film in which the state is fixed and the alignment state is fixed in a homeotropic alignment state.

In step (B), the solvent is removed from the coating film formed in step (A). In addition, by removing the solvent from the coating film in this way, the polymerizable liquid crystal compound in the coating film is aligned in a homeotropic alignment state.

Such a method for removing the solvent varies depending on the kind of the solvent in the liquid crystal composition of the present invention, and is not generally limited, and is not particularly limited. For example, depending on the type of solvent, the solvent can be removed from the coating film even at room temperature (25 ° C.). As described above, according to the liquid crystal composition of the present invention, a homeotropic liquid crystal film can be produced without particular heat treatment depending on the kind of the solvent. Further, the temperature condition in such a solvent removal step is preferably 15 to 110 ° C, more preferably 20 to 70 ° C. If such a temperature condition is less than the lower limit, cooling equipment may be required and efficient production may be difficult.On the other hand, if the upper limit is exceeded, the base material is distorted by heat and optical characteristics and the like change, There is a tendency that desired optical characteristics cannot be obtained.

The pressure condition in such a solvent removal step is not particularly limited, but is preferably 600 to 1400 hPa, and more preferably 900 to 1100 hPa. When the pressure condition is less than the lower limit, the solvent is rapidly dried and uneven drying tends to occur. On the other hand, when the upper limit is exceeded, the solvent tends to take longer to dry. The time for the solvent removal step (drying time) is not particularly limited, but is preferably 10 seconds to 60 minutes, and more preferably 1 minute to 30 minutes. If the drying time is less than the lower limit, the solvent is rapidly dried, and the smoothness of the liquid crystal film tends to be reduced (drying unevenness occurs). Tend to decrease. In the case where a drying apparatus is used for such a solvent removal step, the relative moving speed between the coating film and the drying apparatus is controlled so that the relative wind speed is 60 m / min to 1200 m / min. Is preferred.

In this way, the polymerizable liquid crystal compound can be homeotropically aligned by removing the solvent from the coating film. Then, after the polymerizable liquid crystal compound is aligned, the formed liquid crystal state (homeotropic alignment state) can be fixed by polymerizing the polymerizable liquid crystal compound.

As a method for polymerizing the polymerizable liquid crystal compound to fix the alignment state, a known method capable of polymerization may be appropriately employed depending on the type of the polymerization initiator used or the type of the polymerizable liquid crystal compound. it can. As a method for fixing such an alignment state (polymerization / fixation), for example, the polymerizable group (reactive property) can be obtained by performing light irradiation and / or heat treatment depending on the kind of the polymerization initiator. A method may be adopted in which the orientation is fixed in the homeotropic orientation state by reacting the functional group).

When the polymerization initiator is such that it exhibits the function of an initiator by light irradiation (for example, in the case of a so-called photocation generator), the alignment state of homeotropic alignment is fixed by light irradiation. Is preferred. The light irradiation method is not particularly limited. For example, a light source having a spectrum in the absorption wavelength region of the polymerization initiator used (for example, a metal halide lamp, an intermediate pressure or a high pressure mercury lamp having an illuminance of 10 mW / cm ² or more. (Medium pressure or high pressure mercury ultraviolet lamp), ultra high pressure mercury lamp, low pressure mercury lamp, xenon lamp, arc lamp, laser, etc.) and irradiating light from the light source. In addition, it becomes possible to activate a reaction initiator by such light irradiation, and it becomes possible to react a reactive functional group efficiently.

As the integrated irradiation dose of light in such a method of light irradiation of accumulative exposure at a wavelength 365 nm, it is preferably 10 ~ 2000mJ / cm ^2, and more to be 100 ~ 1500mJ / cm ² preferable. However, this is not the case when the absorption region of the polymerization initiator and the spectrum of the light source are significantly different, or when the polymerizable liquid crystal compound itself has the ability to absorb light of the light source wavelength. In these cases, an appropriate photosensitizer and two or more polymerization initiators having different absorption wavelengths are mixed from the viewpoint of fixing (curing) the coating film while maintaining the orientation state more efficiently. For example, a method such as use may be employed. Further, the temperature condition during such light irradiation is not particularly limited as long as the polymerizable liquid crystal compound can maintain a homeotropic alignment state. A cold mirror or other cooling device may be provided between the substrate and the light source (such as an ultraviolet lamp) so that the surface temperature of the coating film can maintain the range of the liquid crystal temperature during light irradiation.

Furthermore, the conditions of the atmosphere at the time of such light irradiation are not particularly limited, and may be an air atmosphere or a nitrogen atmosphere in which oxygen is blocked in order to increase reaction efficiency. Since the oxygen concentration in the atmosphere is related to the degree of polymerization, when the desired degree of polymerization is not reached in the air, it is preferable to perform light irradiation in an atmosphere in which the oxygen concentration is reduced by a method such as nitrogen substitution. In such a case, the oxygen concentration in the atmospheric gas is preferably 10% by volume or less, more preferably 7% by volume or less, and most preferably 3% by volume or less.

In addition, when the polymerization initiator is such that the function of the initiator is manifested by heat (for example, in the case of a so-called thermal cation generator), the orientation is fixed in a homeotropic alignment state by heat treatment. It is preferable to do. The conditions for such heat treatment are not particularly limited, and the temperature conditions may be selected so that the orientation state is sufficiently maintained according to the type of the polymerization initiator, and known conditions are appropriately employed. be able to.

In addition, when the base material has low heat resistance, a material that exhibits the function of an initiator by light irradiation is used as the polymerization initiator, and the homeotropic alignment state is fixed by light irradiation. It is preferable to do.

Thus, after applying the liquid crystal composition on the substrate, the solvent is removed from the coating film, the polymerizable liquid crystal compound is aligned, and the liquid crystal state is fixed. A homeotropic alignment liquid crystal film fixed in a homeotropic alignment state can be formed on the substrate. The homeotropic alignment liquid crystal film thus obtained has sufficiently high adhesion to the base material, so that it can be directly used as an optical film in the state of a laminate with the base material. In that case, damage due to peeling from the base material during use is sufficiently suppressed.

The thickness of the homeotropic alignment liquid crystal film thus obtained (thickness after drying and curing) varies depending on the application and required properties, but is preferably 0.1 to 10 μm. It is more preferably 2 to 5 μm, and further preferably 0.3 to 2 μm. If the thickness is less than the lower limit, a desired retardation may not be exhibited. On the other hand, if the thickness exceeds the upper limit, the orientation of the liquid crystal tends to decrease.

Moreover, since the method for producing such a homeotropic alignment liquid crystal film of the present invention can form an alignment state of homeotropic alignment by removing the solvent from the coating film of the liquid crystal composition of the present invention, Since it is not necessary to separately perform the step of forming the alignment film on the substrate, the process can be shortened and the cost can be reduced, and after removing the solvent from the coating film of the liquid crystal composition of the present invention, Since it is possible to form an alignment state in a short time (for example, several minutes) after the solvent is removed, when a plastic film is used as a base material, for example, a so-called roll-to-roll method (roll-to-roll method) -Roll method), homeotropic alignment liquid crystal films can be produced. It is also possible to quantity production. In addition, as described above, the method for producing the homeotropic alignment liquid crystal film of the present invention does not need to form an alignment film on the substrate, and does not need to be subjected to heat treatment during formation of the alignment film. Even a film with relatively low heat resistance can be used as a base material, and the thickness of the laminate of the liquid crystal film and the base material can be reduced by the thickness of the alignment film. Therefore, it is possible to efficiently produce a homeotropic alignment liquid crystal film by appropriately selecting a substrate according to the target design.

[Polarizer]
The polarizing plate of the present invention includes the homeotropic alignment liquid crystal film of the present invention.

Such a polarizing plate is not particularly limited, but the homeotropic alignment liquid crystal film of the present invention is used as a known optical material so that the characteristics of the homeotropic alignment liquid crystal film of the present invention can be used. It may be used as a polarizing plate by appropriately combining with a member. For example, the homeotropic alignment liquid crystal film of the present invention may be combined with a linear polarizing plate to form an elliptical polarizing plate, or the homeotropic alignment of the present invention. It is good also as a polarizing plate for LCD backlight sides combining a liquid crystal film and a brightness enhancement film. As described above, the configuration of the polarizing plate is not particularly limited, and the combination with other optical members is appropriately considered depending on the characteristics of the homeotropic alignment liquid crystal film of the present invention and the purpose of use thereof. The design can be changed as appropriate, so that it can be used as various polarizing plates. Here, the homeotropic alignment liquid crystal film of the present invention can be used in the state of a laminate with a substrate.

Here, as a preferred embodiment of the polarizing plate of the present invention, an elliptical polarizing plate that can be obtained by laminating a linear polarizing plate on the homeotropic alignment liquid crystal film of the present invention is taken as an example. I will give you a description. Examples of such an elliptically polarizing plate include those obtained by laminating and integrating the homeotropic alignment liquid crystal film of the present invention and the linear polarizing plate. Such a linear polarizing plate is not particularly limited, and a known linear polarizing plate can be appropriately used. For example, one having a protective film on one side or both sides of a polarizer can be used. Such a polarizer is not particularly limited, and various known materials can be used as appropriate. For example, hydrophilicity such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, ethylene / vinyl acetate copolymer partially saponified film, etc. Examples include polymer films that are uniaxially stretched by adsorbing dichroic substances such as iodine and dichroic dyes, polyene-based oriented films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride. It is done. Among these, a film obtained by stretching a polyvinyl alcohol film and adsorbing and orienting a dichroic material (iodine, dye) is preferably used. The thickness of such a polarizer is not particularly limited, but is generally about 5 to 80 μm.

The protective film is not particularly limited, and a protective film made of a known material can be used as appropriate. Such a protective film is preferably made of a cellulose-based polymer such as triacetyl cellulose from the viewpoints of polarization characteristics and durability. In addition, a method for laminating and integrating the homeotropic alignment liquid crystal film and the linear polarizing plate is not particularly limited. For example, one of the surfaces of the homeotropic alignment liquid crystal film and the linear polarizing plate to be laminated with each other or What is necessary is just to crimp | bond, after forming an adhesive and / or an adhesive bond layer by an appropriate method to both. The crimping can be performed either in a leaf-like form or in a long form, and the apparatus to be used may be an apparatus suitable for each form, and examples thereof include a press and a laminator. Moreover, the material for forming such a pressure-sensitive adhesive layer and / or adhesive layer is not particularly limited, and a known material can be appropriately used.

[Image display device]
The image display device of the present invention includes the polarizing plate of the present invention. Such an image display device of the present invention only needs to include the polarizing plate of the present invention, and the type of the image display device is not particularly limited, such as a liquid crystal display device, an organic EL display device, and a plasma display. Such known image display devices can be used as appropriate. Further, the method for arranging the polarizing plate of the present invention in an image display device is not particularly limited, and a known method can be appropriately used. Thus, the image display device of the present invention including the polarizing plate of the present invention includes a liquid crystal film of homeotropic alignment (vertical alignment) having a larger refractive index in the film thickness direction. Depending on the characteristics, for example, the viewing angle of the image display device can be sufficiently widened, the luminance can be sufficiently improved, and the like, and thereby the viewing angle and the image quality can be sufficiently improved.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
<Preparation of liquid crystal composition>
First, the following general formulas (110) to (113):

A polymerizable liquid crystal compound represented by the formula (acrylate-based polymerizable liquid crystal compound) was prepared. The polymerizable liquid crystal compounds represented by the general formulas (110) to (113) were produced by known methods. Specifically, the compound represented by the above general formula (110) (hereinafter sometimes simply referred to as “liquid crystal compound (I)”) is described in British Patent Application Publication No. 2,280,445 (GB2,280,445). The compound represented by the above general formula (111) (hereinafter sometimes simply referred to as “liquid crystal compound (II)”) is a document published in 1989 (DJ Broer). et al., “Makromol. Chem.”, vol. 190, 1989, pages 3201 to 3215), and a compound represented by the above general formula (112) (hereinafter, depending on circumstances) The compounds represented simply by “Liquid Crystal Compound (III)”) and (113) (hereinafter sometimes simply referred to as “Liquid Crystal Compound (IV)”) are disclosed in International Publication 93. It was prepared by the method described in JP 22397. Further, all of the polymerizable liquid crystal compounds represented by the above general formulas (110) to (113) were solid at room temperature (25 ° C.).

Next, the liquid crystal compounds (I) to (IV) are mixed with liquid crystal compound (I): 35 mass%, liquid crystal compound (II): 23 mass%, liquid crystal compound (III): 23 mass%, and liquid crystal compound ( IV): The first mixture (liquid crystal monomer mixture) was obtained by mixing at a mass ratio of 19% by mass. Next, a polymerization initiator (trade name “Irgacure 907” manufactured by Ciba-Geigy, Switzerland, solid at room temperature (25 ° C.)) is added to the liquid crystal compounds (I) to (1) to the first mixture. The second mixture (solid) obtained by adding 5.0 parts by mass with respect to 100 parts by mass of the total amount of IV) and mixing the liquid crystal compounds (I) to (IV) and the polymerization initiator ) Next, the second mixture was dissolved in propylene glycol 1-monomethyl ether 2-acetate (solvent) to obtain a third mixture (mixed solution). In producing the third mixture, the content of the solvent in the third mixture is 80% by mass, and the total amount of the liquid crystal compounds (I) to (IV) and the polymerization initiator is The solvent was used so that it might become 20 mass%.

Next, with respect to the third mixture (mixed solution), triphenylphosphine (trade name “Triphenylphosphine” manufactured by Kishida Chemical Co., Ltd.) is added to the liquid crystal compound contained in the third mixture (mixed solution) ( A polymerizable liquid crystal compound represented by the above general formulas (110) to (113) (the liquid crystal compound (I)) is added at a ratio of 5.0 parts by mass with respect to 100 parts by mass of the total amount of I) to (IV). To (IV) mixture), triphenylphosphine, a polymerization initiator, and a solvent were obtained.

<Preparation of liquid crystal film>
First, a COP film (trade name “Zeonor” manufactured by Nippon Zeon Co., Ltd., film thickness: 20 μm) is prepared as a base material, and corona discharge treatment (corona discharge irradiation amount: 100 W / m ² · min) is applied to the base material. gave. Next, the liquid crystal composition obtained as described above was applied (coated) to the base material (COP film) after the corona discharge treatment by a spin coating method to form a coating film (wet film thickness: 5 μm). ) To obtain a laminate of the coating film and the substrate.

Next, the laminate of the coating film and the substrate was left to stand for 2 minutes under the conditions of pressure: 1013 hPa and temperature: room temperature (25 ° C.), thereby removing the solvent from the coating film by drying (solvent removal step). ). In addition, the solvent was removed from the whole surface of the said coating film after 2 minutes passed from the completion of the coating to a base material. Moreover, in such a solvent removal process, after arrange | positioning the laminated body of the said coating film and a base material between a pair of orthogonal polarizing plates, and standing the laminated body of the said coating film and a base material (liquid crystal composition) After the coating of the product is completed), the coating state of the liquid crystal composition is completed when the state of the coating film (dried state and orientation state) is confirmed with the naked eye from a direction perpendicular to the coating film surface after 2 minutes have passed. After about 1 minute, the liquid crystal compound is homeotropically aligned (vertically aligned) in the coating as the solvent is dried, and the solvent is removed from the entire surface of the coating after 2 minutes from the completion of coating. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the dried coating film.

Next, with respect to the coating film dried by the solvent removal step, using a high-pressure mercury lamp with an illuminance of 15 mW / cm ² , the integrated irradiation amount is 200 mJ / cm ^2, and ultraviolet light (however, A liquid crystal film in which the alignment state is fixed by polymerizing (curing) the liquid crystal compound by irradiating light having a wavelength of 365 nm, and the alignment state is fixed on the substrate (COP film). A laminated liquid crystal film laminate (a laminate of a liquid crystal film and a COP film) was obtained. When the film thickness of the liquid crystal film in the liquid crystal film laminate thus obtained was measured using a trade name “Digimicro” manufactured by Nikon Corporation, the film thickness of the liquid crystal film was 1 μm.

<Measurement of alignment state of liquid crystal film>
The optical properties of the liquid crystal film thus obtained were evaluated as follows. That is, the liquid crystal film laminate was used as a measurement sample, the product name “axoscan” manufactured by axo-matrix was used as a measurement device, the measurement light was changed to 590 nm, and the viewing angle was changed from 0 ° to larger ( When the direction perpendicular to the liquid crystal film is set to a viewing angle of 0 °, the phase difference is measured at various viewing angles, and the direction perpendicular to the liquid crystal film is measured from another angle (the viewing angle is The optical properties of the liquid crystal film were evaluated by confirming the difference in the phase difference of the sample from the case where the angle was changed to a larger angle.

In the measurement sample provided with the liquid crystal film obtained as described above by the measurement of such a phase difference, no phase difference is confirmed in a direction perpendicular to the liquid crystal film (viewing angle is 0 °) ( It was confirmed that the phase difference increases as the viewing angle increases. In addition, in the measurement of the phase difference, it was confirmed that the liquid crystal film had symmetry in the phase difference value in the − direction and the + direction of the viewing angle. Therefore, the liquid crystal film thus obtained has liquid crystal molecules aligned in a direction perpendicular to the film surface (the surface of the liquid crystal film) (homeotropic alignment is formed). confirmed.

<Measurement of adhesion of liquid crystal film to substrate>
In order to examine the interlayer adhesion between the substrate (COP film) and the liquid crystal film, 10 pressure-sensitive adhesive tapes (trade name “Mending Tape 810” manufactured by 3M) were applied on the surface of the liquid crystal film of the liquid crystal film laminate. After pressing and adhering at a pressure of ⁷ N / m ^2, the adhesive tape is peeled off from the liquid crystal film laminate at a speed of 150 cm / s to form an interface between the base material (COP film) and the liquid crystal film. It was confirmed whether peeling occurred or not, and the adhesion between the substrate (COP film) and the liquid crystal film was measured.

According to such measurement, peeling occurred at the interface between the adhesive tape and the liquid crystal film, and no peeling was confirmed between the base material (COP film) and the liquid crystal film. Therefore, it was confirmed that the liquid crystal film laminate obtained as described above has a sufficiently high interlayer adhesion between the base material (COP film) and the liquid crystal film. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 2)
A liquid crystal film laminate (base) was prepared in the same manner as in Example 1 except that the amount of triphenylphosphine added was changed to 3.0 parts by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). A laminate of a material (COP film) and a liquid crystal film (thickness: 1 μm) was obtained.

In Example 2, as in Example 1, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition, When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the alignment state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Example 2, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). Moreover, when the liquid crystal film laminate obtained in Example 2 was used to measure the adhesion of the liquid crystal film to the substrate in the same manner as in Example 1, the substrate (COP) was measured. No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 3)
A liquid crystal film laminate (base) was prepared in the same manner as in Example 1, except that the addition amount of the triphenylphosphine was changed to 1.0 part by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). A laminate of a material (COP film) and a liquid crystal film (thickness: 1 μm) was obtained.

Also in Example 3, as in Example 1, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition. When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of a liquid crystal film (cured liquid crystal film) was measured in the same manner as in the method employed in Example 1 using the liquid crystal film laminate obtained in Example 3, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). Moreover, when the liquid crystal film laminate obtained in Example 3 was used to measure the adhesion of the liquid crystal film to the substrate in the same manner as in the method employed in Example 1, the substrate (COP) was measured. No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 4)
The mass ratio of the liquid crystal compounds (I) to (IV) in obtaining the first mixture (liquid crystal monomer mixture) is as follows: liquid crystal compound (I): 38 mass%, liquid crystal compound (II): 25 mass%, liquid crystal compound (III): A liquid crystal film laminate (base material (COP film) and liquid crystal film (thickness: thickness) in the same manner as in Example 1 except that it was changed to 25% by mass and liquid crystal compound (IV): 12% by mass. 1 μm) was obtained.

Also in Example 4, as in Example 1, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition, When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Example 4, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). Further, when the adhesion of the liquid crystal film to the substrate was measured using the liquid crystal film laminate obtained in Example 4 in the same manner as the method employed in Example 1, the substrate (COP) was measured. No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 5)
A liquid crystal film laminate (base) was prepared in the same manner as in Example 4 except that the amount of triphenylphosphine added was changed to 3.0 parts by mass relative to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). A laminate of a material (COP film) and a liquid crystal film (thickness: 1 μm) was obtained.

In Example 5, as in Example 4, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition, When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Example 5, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). Moreover, when the liquid crystal film laminate obtained in Example 5 was used to measure the adhesion of the liquid crystal film to the base material in the same manner as in Example 1, the base material (COP) No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 6)
A liquid crystal film laminate (base) was prepared in the same manner as in Example 4 except that the amount of triphenylphosphine added was changed to 1.0 part by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). A laminate of a material (COP film) and a liquid crystal film (thickness: 1 μm) was obtained.

In Example 6, as in Example 4, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition. When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Example 6, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). In addition, when the liquid crystal film laminate obtained in Example 6 was used to measure the adhesion of the liquid crystal film to the substrate in the same manner as in the method employed in Example 1, the substrate (COP) was measured. No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Example 7)
Instead of the triphenylphosphine, trishydroxymethylphosphine (trade name “Tris (hydroxymethyl) phosphine” manufactured by Aldrich) was used, and the amount of the trishydroxymethylphosphine added was the total amount of the liquid crystal compounds (I) to (IV). A liquid crystal film laminate (a laminate of a base material (COP film) and a liquid crystal film (thickness: 1 μm)) was obtained in the same manner as in Example 4 except that 1.0 part by mass with respect to 100 parts by mass was obtained. .

In Example 7, as in Example 4, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after the completion of the coating of the liquid crystal composition. When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Example 7, the Example In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed). Further, when the adhesion of the liquid crystal film to the substrate was measured using the liquid crystal film laminate obtained in Example 7 in the same manner as in the method employed in Example 1, the substrate (COP) was measured. No peeling was confirmed between the film) and the liquid crystal film, and it was confirmed that the interlayer adhesion between the substrate (COP film) and the liquid crystal film was sufficiently high. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 1)
A polymerizable liquid crystal compound represented by the above general formulas (110) to (113) (a mixture of the liquid crystal compounds (I) to (IV)) and a polymerization initiator are added without adding triphenylphosphine during the preparation of the liquid crystal composition. A liquid crystal film laminate (a substrate (COP film) and a cured film of the liquid crystal composition [liquid crystal film (thickness: thickness)) was used in the same manner as in Example 1 except that a mixture with a solvent was used as a comparative liquid crystal composition. 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Was measured, and in the liquid crystal film laminate obtained in Comparative Example 1, severe light leakage was confirmed, and the liquid crystal molecules in the formed liquid crystal film (cured film of the liquid crystal composition) were vertically aligned. I found out that it was not. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 2)
In the solvent removal step, the liquid crystal film laminate (base material (COP film) and the above-described material was used in the same manner as in Comparative Example 1 except that the time for drying and removing the solvent (time for standing) was changed from 2 minutes to 1 hour. A cured film of the liquid crystal composition [a laminate with a liquid crystal film (thickness: 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Is measured, in the liquid crystal film laminate obtained in Comparative Example 2, severe light leakage is confirmed, and the liquid crystal molecules are vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 3)
A polymerizable liquid crystal compound represented by the above general formulas (110) to (113) (a mixture of the liquid crystal compounds (I) to (IV)) and a polymerization initiator are added without adding triphenylphosphine during the preparation of the liquid crystal composition. A liquid crystal film laminate (a substrate (COP film) and a cured film of the liquid crystal composition [liquid crystal film (thickness: thickness)) was used in the same manner as in Example 4 except that a mixture with a solvent was used as a liquid crystal composition for comparison. 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Was measured, and in the liquid crystal film laminate obtained in Comparative Example 3, severe light leakage was confirmed, and the liquid crystal molecules were vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out that it was not. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 4)
A liquid crystal film laminate (base material (COP film) and the above-mentioned) was used in the same manner as in Comparative Example 3, except that the time for drying and removing the solvent (time for standing) was changed from 2 minutes to 1 hour in the solvent removal step. A cured film of the liquid crystal composition [a laminate with a liquid crystal film (thickness: 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Is measured, in the liquid crystal film laminate obtained in Comparative Example 4, severe light leakage is confirmed, and the liquid crystal molecules are vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 5)
Example 3 was repeated except that triethylamine was used in place of the triphenylphosphine, and the addition amount of the triethylamine was 5.0 parts by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). Thus, a liquid crystal film laminate (a laminate of a substrate (COP film) and a cured film of the liquid crystal composition [liquid crystal film (thickness: 1 μm)]) was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Was measured, and in the liquid crystal film laminate obtained in Comparative Example 5, severe light leakage was confirmed, and the liquid crystal molecules were vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out that it was not. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 6)
A liquid crystal film laminate (base material (COP film) and the above-mentioned) was used in the same manner as in Comparative Example 5 except that the time for drying and removing the solvent (time for standing) was changed from 2 minutes to 1 hour in the solvent removal step. A cured film of the liquid crystal composition [a laminate with a liquid crystal film (thickness: 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Is measured, in the liquid crystal film laminate obtained in Comparative Example 6, severe light leakage is confirmed, and the liquid crystal molecules are vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 7)
Example except that triphenylamine was used in place of the triphenylphosphine, and the addition amount of the triphenylamine was 5.0 parts by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). 4, a liquid crystal film laminate (a laminate of a substrate (COP film) and a cured film of the liquid crystal composition [liquid crystal film (thickness: 1 μm)]) was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Was measured, and in the liquid crystal film laminate obtained in Comparative Example 7, severe light leakage was confirmed, and the liquid crystal molecules in the formed liquid crystal film (cured film of the liquid crystal composition) were vertically aligned. I found out that it was not. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 8)
The liquid crystal film laminate (base material (COP film) and the above-described material was used in the same manner as in Comparative Example 7 except that the time for drying and removing the solvent (time for standing) was changed from 2 minutes to 1 hour in the solvent removal step. A cured film of the liquid crystal composition [a laminate with a liquid crystal film (thickness: 1 μm)] was obtained.

The liquid crystal film laminate is disposed between a pair of orthogonal polarizing plates, and the liquid crystal film (cured film of the liquid crystal composition) is observed with the naked eye from a direction perpendicular to the surface of the liquid crystal film (cured film of the liquid crystal composition). ) Is measured, in the liquid crystal film laminate obtained in Comparative Example 8, severe light leakage is confirmed, and liquid crystal molecules are vertically aligned in the formed liquid crystal film (cured film of the liquid crystal composition). I found out. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 9)
Instead of the triphenylphosphine, a fluorosurfactant (trade name “SURFLON S-386” manufactured by AGC Seimi Chemical Co., Ltd.) was used, and the amount of the fluorosurfactant added was determined in the liquid crystal compounds (I) to (I) IV) A liquid crystal film laminate (a laminate of a substrate (COP film) and a liquid crystal film (thickness: 1 μm)) in the same manner as in Example 4 except that the amount was 0.5 parts by mass with respect to 100 parts by mass in total. )

Further, when the alignment state of the liquid crystal film (cured liquid crystal film) was measured in the same manner as the method employed in Example 1 using the liquid crystal film laminate obtained in Comparative Example 9, the liquid crystal film was measured. It was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed).

Furthermore, when the adhesion of the liquid crystal film to the substrate was measured using the liquid crystal film laminate obtained in Comparative Example 9 in the same manner as in the method employed in Example 1, the substrate (COP) Peeling occurred between the film) and the liquid crystal film. Thus, in the liquid crystal film laminate obtained in Comparative Example 9, since the peeling interface was an interface between the base material (COP film) and the liquid crystal film, the base material (COP film) and the liquid crystal film It was found that the interlaminar adhesion between the two was insufficient. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Comparative Example 10)
In place of the triphenylphosphine, an acetylene glycol surfactant (trade name “Orphine EXP4036” manufactured by Nissin Chemical Industry Co., Ltd.) was used, and the amount of the acetylene glycol surfactant added was determined in the liquid crystal compounds (I) to (I) IV) A liquid crystal film laminate (a laminate of a substrate (COP film) and a liquid crystal film (thickness: 1 μm)) in the same manner as in Example 4 except that the amount was 0.5 parts by mass with respect to 100 parts by mass in total. )

Moreover, when the orientation state of a liquid crystal film (cured liquid crystal film) was measured in the same manner as in Example 1 using the liquid crystal film laminate obtained in Comparative Example 10, the example was In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed).

Furthermore, when the adhesion of the liquid crystal film to the substrate was measured using the liquid crystal film laminate obtained in Comparative Example 10 in the same manner as in Example 1, the substrate (COP) Peeling occurred between the film) and the liquid crystal film. Thus, in the liquid crystal film laminate obtained in Comparative Example 10, since the peeling interface was an interface between the base material (COP film) and the liquid crystal film, the base material (COP film) and the liquid crystal film It was found that the interlaminar adhesion between the two was insufficient. The characteristics of such a liquid crystal film laminate are shown in Table 1.

(Reference Example 1)
Triphenylphosphine oxide was used instead of triphenylphosphine, and the addition amount of the triphenylphosphine oxide was 5.0 parts by mass with respect to 100 parts by mass of the total amount of the liquid crystal compounds (I) to (IV). In the same manner as in Example 4, a liquid crystal film laminate (a laminate of a base material (COP film) and a liquid crystal film (thickness: 1 μm)) was obtained.

Also in Reference Example 1, as in Example 4, when the state of the coating film (dried state and orientation state) was confirmed in the solvent removal step, about 1 minute after completion of the coating of the liquid crystal composition. When the solvent is dried, a portion where the liquid crystal compound is homeotropically aligned (vertical alignment) appears in the coating film, and after 2 minutes from the completion of the coating, the solvent is removed from the entire surface of the coating film. It was confirmed that the liquid crystal compound had homeotropic alignment (vertical alignment) over the entire surface of the coating film.

Moreover, when the orientation state of the liquid crystal film (cured liquid crystal film) was measured using the liquid crystal film laminate obtained in Reference Example 1 in the same manner as the method employed in Example 1, In the same manner as in No. 1, it was confirmed that the liquid crystal molecules were aligned in a direction perpendicular to the liquid crystal film surface (homeotropic alignment was formed).

Furthermore, when the adhesion of the liquid crystal film to the substrate was measured using the liquid crystal film laminate obtained in Reference Example 1 in the same manner as in Example 1, the substrate (COP) Peeling occurred between the film) and the liquid crystal film. Thus, in the liquid crystal film laminate obtained in Reference Example 1, since the peeling interface was an interface between the base material (COP film) and the liquid crystal film, the base material (COP film) and the liquid crystal film It was found that the interlaminar adhesion between the two was insufficient. The characteristics of such a liquid crystal film laminate are shown in Table 1.

As is clear from the results shown in Table 1 and the like, when the liquid crystal composition of the present invention was used (Examples 1 to 7: liquid crystal compositions using a phosphine compound), the liquid crystal film formed thereby was Both were confirmed to be homeotropic alignment liquid crystal films. In the case of using the liquid crystal composition of the present invention (Examples 1 to 7: liquid crystal compositions using a phosphine compound), workability is high because a chemically stable component is used. Since the homeotropic alignment is formed by a simple process such as removing the solvent for 2 minutes, the liquid crystal compound can be homeotropically aligned in a very short time, and the homeotropic alignment liquid crystal film can be efficiently produced. It was confirmed that it was possible. Further, in the case of using the liquid crystal composition of the present invention (Examples 1 to 7: liquid crystal compositions using a phosphine compound), a homeotropic alignment liquid crystal film and a substrate (COP film) were used in the adhesion measurement test. It was also confirmed that there was no delamination between the layers and the adhesion between the homeotropic alignment liquid crystal film and the substrate (COP film) was sufficiently high. From these results, when the liquid crystal composition of the present invention is used (Examples 1 to 7: liquid crystal compositions using a phosphine compound), the obtained liquid crystal film laminate is a homeotropic alignment liquid crystal film and a substrate. Since the delamination between the (COP film) and the COP film is sufficiently suppressed, it can be seen that the laminate can be applied to various uses in the state of the laminate.

On the other hand, in the case where a mixture of a polymerizable liquid crystal compound, a polymerization initiator, and a solvent was used as a comparative liquid crystal composition (Comparative Examples 1 to 4) without using a phosphine compound, the liquid crystal molecules were homeotropic. It was confirmed that the liquid crystal molecules could not be homeotropically aligned even if the solvent could not be aligned and the solvent removal time (standing time) was 1 hour. In addition, when an additive such as triethylamine or triphenylamine is used instead of the phosphine compound (Comparative Examples 5 to 8), the chemical structure of the additive is similar to the chemical structure of the phosphine compound. The liquid crystal molecules could not be homeotropically aligned even if the removal time (time of standing) was 1 hour. In the case where an additive made of a surfactant was used instead of the phosphine compound (Comparative Examples 9 to 10), although the obtained liquid crystal films were all liquid crystals having homeotropic alignment, In the measurement test, delamination occurs between the homeotropic alignment liquid crystal film and the substrate (COP film), and the adhesion between the homeotropic alignment liquid crystal film and the substrate (COP film) can be made sufficient. There wasn't. Further, in Reference Example 1 using triphenylphosphine oxide instead of the phosphine compound, the obtained liquid crystal film was a homeotropic alignment liquid crystal film, but the homeotropic alignment liquid crystal film and the substrate (COP film) It has been found that the adhesiveness to) cannot always be sufficient.

As described above, according to the present invention, the workability during the production of a liquid crystal film can be sufficiently improved, and a homeotropic alignment liquid crystal film can be efficiently produced. Liquid crystal composition capable of making sufficiently high adhesion between substrate and homeotropic alignment liquid crystal film when manufactured on material, homeotropic alignment liquid crystal film and polarizing plate obtained using the same In addition, it is possible to provide an image display device and a method for producing a homeotropic alignment liquid crystal film using the liquid crystal composition.

Therefore, the liquid crystal composition of the present invention is particularly useful as a material for producing a homeotropic alignment liquid crystal film.

Claims

A liquid crystal composition comprising (A) a polymerizable liquid crystal compound, (B) a phosphine compound, (C) a polymerization initiator, and (D) a solvent capable of dissolving the components (A) to (C).
The phosphine compound has the following general formula (1):

[Wherein R 1 to R 3 each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 30 carbon atoms, and an optionally substituted aryl group having 6 to 18 carbon atoms. Any one selected from the group consisting of groups is shown. ]
The liquid crystal composition according to claim 1, which is at least one selected from the group of compounds represented by:
The phosphine compound is represented by the general formula (1), and R 1 to R 3 in the formula each independently have a substituent having 1 to 30 carbon atoms and a substituent. 3. The liquid crystal composition according to claim 2, wherein the liquid crystal composition is at least one selected from tertiary phosphines which are any one selected from the group consisting of aryl groups having 6 to 12 carbon atoms which may have. object.
The phosphine compound is trimethylphosphine, triethylphosphine, tri-n-butylphosphine, tri-tert-butylphosphine, tri-n-octylphosphine, tricyclohexylphosphine, trishydroxymethylphosphine, trishydroxyethylphosphine, triphenylphosphine, The liquid crystal composition according to any one of claims 1 to 3, which is at least one selected from the group consisting of trismethoxyphenylphosphine and trisethoxyphenylphosphine.
The liquid crystal composition according to any one of claims 1 to 4, wherein the phosphine compound is at least one of trishydroxymethylphosphine and triphenylphosphine.
The liquid crystal composition according to any one of claims 1 to 5, wherein the polymerizable liquid crystal compound is a (meth) acrylate-based liquid crystal compound.
The liquid crystal composition according to any one of claims 1 to 6, wherein a content of the phosphine compound is 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.
The liquid crystal composition according to any one of claims 1 to 7, wherein a content of the polymerization initiator is 1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.
A homeotropic alignment liquid crystal film fixed in a homeotropic alignment state, wherein the homeotropic alignment liquid crystal film is obtained using the liquid crystal composition according to any one of claims 1 to 8. Tropic alignment liquid crystal film.
A polarizing plate comprising the homeotropic alignment liquid crystal film according to claim 9.
An image display device comprising the polarizing plate according to claim 10.
A step of coating the liquid crystal composition according to any one of claims 1 to 8 on a substrate to form a coating film; and removing the solvent from the coating film to convert the polymerizable liquid crystal compound into a homeo After the tropic alignment, the alignment state is fixed by polymerizing the polymerizable liquid crystal compound, and a homeotropic alignment liquid crystal film in which the alignment state is fixed in a homeotropic alignment state is obtained. A method for producing a liquid crystal film.
The method for producing a homeotropic alignment liquid crystal film according to claim 12, wherein the substrate is a film made of a cyclic olefin polymer.
The method for producing a homeotropic alignment liquid crystal film according to claim 12 or 13, wherein a temperature condition for removing the solvent from the coating film is 15 to 110 ° C.