JP2020166059A - Manufacturing method for liquid crystal hardening film - Google Patents

Abstract

To provide a manufacturing method for liquid crystal hardening film with excellent orientation, in which a bright spot is suppressed.SOLUTION: A manufacturing method for liquid crystal hardening film formed of a hardened liquid crystal composition including a liquid crystal compound that can exhibit birefringence with a reverse wavelength dispersion property includes a step of performing a rubbing process on a surface of a base material, a step of cleaning the rubbed surface of the base material with a solvent, a step of applying the liquid crystal composition on the cleaned surface of the base material so as to form a layer of the liquid crystal composition, and a step of hardening the layer of the liquid crystal composition.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a liquid crystal cured film formed of a cured product of a liquid crystal composition containing a liquid crystal compound.

Conventionally, a method of producing a film using a liquid crystal composition containing a liquid crystal compound has been known. For example, Patent Documents 1 and 2 describe techniques for coating a liquid crystal composition on a base material and curing the coated liquid crystal composition to produce a film.

Japanese Unexamined Patent Publication No. 2004-117657 JP-A-2002-040245

The liquid crystal cured film formed of the cured product of the liquid crystal composition can have various optical characteristics depending on the orientation state of the liquid crystal compound contained in the liquid crystal cured film. Therefore, the liquid crystal cured film may be used as an optical film. When used as an optical film, it is desirable that the formation of bright spots is suppressed in the liquid crystal cured film. The above-mentioned "bright spot" means a spot that looks shining when an optical film is placed between a polarizing element and an analyzer arranged on a cross Nicol and observed, and optical defects such as foreign matter, protrusions, and dents are present. It can occur in the formed part. Since the bright spot can be formed by, for example, the presence of foreign matter such as dust on the base material, Patent Documents 1 and 2 propose to clean the base material to remove the foreign matter.

However, the liquid crystal cured film is required not only to suppress the formation of bright spots as described above, but also to have excellent orientation. Here, the fact that the liquid crystal cured film is excellent in orientation means that the disorder in the orientation direction of the liquid crystal compound contained in the liquid crystal cured film is small. Therefore, it is necessary to develop a technique that can achieve both suppression of bright spots and improvement of orientation.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a method for producing a liquid crystal cured film having suppressed bright spots and excellent orientation.

The present inventor has diligently studied to solve the above-mentioned problems. As a result, the present inventor has a step of applying a rubbing treatment to the surface of the base material; a step of cleaning the surface of the base material to which the rubbing treatment has been performed with a solvent; and a reverse step to the washed surface of the base material. It has been found that the above-mentioned problems can be solved by a production method including a step of forming a layer of a liquid crystal composition containing a liquid crystal compound capable of exhibiting wavelength-dispersible birefringence; and a step of curing the layer of the liquid crystal composition; , The present invention has been completed.
That is, the present invention includes the following.

[1] A method for producing a liquid crystal cured film formed of a cured product of a liquid crystal composition containing a liquid crystal compound capable of exhibiting birefringence of inverse wavelength dispersibility.
The process of rubbing the surface of the base material and
A step of cleaning the surface of the base material that has been subjected to the rubbing treatment with a solvent, and
A step of forming a layer of the liquid crystal composition on the washed surface of the base material, and
A method for producing a liquid crystal cured film, which comprises a step of curing a layer of the liquid crystal composition.
[2] The method for producing a liquid crystal cured film according to [1], wherein the SP value of the solvent is 12 or more.
[3] The method for producing a liquid crystal cured film according to [1] or [2], wherein the SP value of the solvent is 24 or less.
[4] The method for producing a liquid crystal cured film according to any one of [1] to [3], wherein the difference between the SP value of the base material and the SP value of the solvent is 2 or more.
[5] The liquid crystal cured film according to any one of [1] to [4], wherein the substantially maximum inclination angle of the molecule of the liquid crystal compound contained in the liquid crystal cured film is 5 ° or more and 85 ° or less. Manufacturing method.
[6] The method for producing a liquid crystal cured film according to any one of [1] to [5], wherein the base material contains an alicyclic structure-containing polymer.
[7] The method for producing a liquid crystal cured film according to any one of [1] to [6], wherein the base material is long.
[8] The method for producing a liquid crystal cured film according to [7], wherein the rubbing direction of the rubbing treatment forms an angle of 40 ° or more and 50 ° or less in the longitudinal direction of the base material.
[9] The method for producing a liquid crystal cured film according to any one of [1] to [8], wherein the base material does not have an alignment film.

According to the present invention, it is possible to provide a method for producing a liquid crystal cured film in which bright spots are suppressed and the orientation is excellent.

FIG. 1 is a side view schematically showing an example of a rubbing device according to an embodiment and an operation of a rubbing process using the rubbing device. FIG. 2 is a top view schematically showing an example of a rubbing device according to an embodiment and an operation of a rubbing process using the rubbing device. FIG. 3 is a rear view schematically showing an example of a rubbing device according to an embodiment and an operation of a rubbing process using the rubbing device. FIG. 4 is a side view schematically showing the relationship between the rubbing roll A130 and the strip-shaped base material in the rubbing apparatus A100 shown in FIGS. 1 to 3. FIG. 5 is a side view schematically showing the relationship between the rubbing roll A130 and the strip-shaped base material in the rubbing apparatus A100 shown in FIGS. 1 to 3. FIG. 6 is a side view schematically showing an example of a rubbing device according to another embodiment and an operation of a rubbing process using the rubbing device. FIG. 7 is a top view schematically showing an example of a rubbing device according to another embodiment and an operation of a rubbing process using the rubbing device. FIG. 8 is a side view schematically showing the relationship between the floating transport device C120, the rubbing roll C130, the floating transport device C140, and the strip-shaped base material in the rubbing device C100 shown in FIGS. 6 to 7. FIG. 9 is a side view schematically showing the relationship between the rubbing roll C130 in the rubbing apparatus C100 shown in FIGS. 6 to 7 and the strip-shaped base material C14 carried out from the rubbing roll C130. FIG. 10 is a perspective view schematically showing the levitation transport device C120 in the rubbing device C100 shown in FIGS. 6 and 7. FIG. 11 is a side view schematically showing the levitation transfer device C120 in the rubbing device C100 shown in FIGS. 6 and 7. FIG. 12 is a bottom view schematically showing the levitation transport device C120 in the rubbing device C100 shown in FIGS. 6 and 7.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, the "in-plane direction" of a layer represents a direction parallel to the layer plane unless otherwise specified.

In the following description, the "thickness direction" of a layer means the direction perpendicular to the layer plane unless otherwise specified. Therefore, unless otherwise specified, the in-plane direction and the thickness direction of a certain layer are perpendicular to each other.

In the following description, when an element is "inclined" with respect to a layer plane, it means that the element is neither parallel nor perpendicular to the layer plane. The angle formed by the element with respect to the layer plane is usually in the range of 5 ° or more and 85 ° or less.

In the following description, unless otherwise specified, the birefringence inverse wavelength dispersibility means that the birefringence Δn (450) at a wavelength of 450 nm and the birefringence Δn (550) at a wavelength of 550 nm satisfy the following equation (N1). Say. A liquid crystal compound capable of exhibiting such an inverse wavelength-dispersible birefringence can usually exhibit a larger birefringence as the measurement wavelength is longer.
Δn (450) <Δn (550) (N1)

In the following description, the in-plane retardation Re of a certain layer is a value represented by Re = (nx−ny) × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and in the direction giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and orthogonal to the nx direction. d represents the thickness of the layer. The measurement wavelength of the retardation is 590 nm unless otherwise specified. The in-plane retardation Re can be measured using a phase difference meter (“AxoScan” manufactured by Axometrics).

In the following description, the slow axis of a certain layer means the slow axis in the in-plane direction unless otherwise specified.

In the following description, unless otherwise specified, the "tilt angle" of the molecules of the liquid crystal compound contained in a certain layer represents the angle formed by the molecules of the liquid crystal compound with respect to the layer plane, and is also referred to as "tilt angle". Sometimes called. This inclination angle corresponds to the maximum angle among the angles formed by the direction of the maximum refractive index in the refractive index ellipsoid of the molecule of the liquid crystal compound with the layer plane. Further, in the following description, unless otherwise specified, the “inclination angle” represents the inclination angle of the molecule of the liquid crystal compound with respect to the layer plane of the layer containing the liquid crystal compound.

In the following description, the directions of the elements are "parallel" and "vertical", unless otherwise specified, within a range that does not impair the effect of the present invention, for example, ± 4 °, preferably ± 3 °, more preferably ± 1. It may include errors within the range of °.

In the following description, the number of carbon atoms of a group having a substituent does not include the number of carbon atoms of the substituent unless otherwise specified. Therefore, for example, the description of "an alkyl group having 1 to 20 carbon atoms which may have a substituent" means that the number of carbon atoms of the alkyl group itself which does not include the number of carbon atoms of the substituent is the number of carbon atoms, unless otherwise specified. Indicates that it is 1 to 20.

In the following description, "wave plate" is used as a term including flexible films and sheets such as resin films unless otherwise specified.

In the following description, the "long shape" means a shape having a length of 5 times or more with respect to the width, preferably having a length of 10 times or more, and specifically a roll shape. A shape that has a length that allows it to be wound up and stored or transported. The upper limit of the length is not particularly limited and may be, for example, 100,000 times or less the width.

[1. Outline of manufacturing method of liquid crystal cured film]
In the method for producing a liquid crystal cured film according to an embodiment of the present invention, a liquid crystal cured film formed of a cured product of a liquid crystal composition containing a liquid crystal compound capable of exhibiting birefringence of inverse wavelength dispersibility is produced. In the following description, "a liquid crystal compound capable of expressing birefringence of reverse wavelength dispersibility" may be referred to as "reverse dispersion liquid crystal compound".

The method for producing a liquid crystal cured film according to this embodiment is
The process of applying a rubbing treatment to the surface of the base material;
A step of cleaning the surface of the base material that has been subjected to the rubbing treatment with a solvent;
A step of forming a layer of a liquid crystal composition on the washed surface of the substrate;
A process of curing a layer of a liquid crystal composition to obtain a liquid crystal cured film;
including. Further, the method for producing a liquid crystal cured film according to the present embodiment may further include an arbitrary step in combination with the above steps.

According to the production method according to the present embodiment, it is possible to produce a liquid crystal cured film having suppressed bright spots and excellent orientation. Further, according to this manufacturing method, it is usually possible to improve the planarity and orientation uniformity of the liquid crystal cured film.

[2. Preparation of base material]
A method for producing a liquid crystal cured film usually includes a step of preparing a base material.
As the material of the base material, any material capable of forming a surface capable of exhibiting the orientation regulating force by the rubbing treatment can be adopted. The "orientation regulating force" refers to a surface property capable of orienting a molecule of a liquid crystal compound contained in a liquid crystal composition. In particular, resin is preferable as the material of the base material. The surface formed of the resin of the base material is likely to exert an orientation regulating force by rubbing treatment.

As the resin, a thermoplastic resin is preferable. The thermoplastic resin usually contains a polymer and optionally any component. As the polymer, an alicyclic structure-containing polymer is more preferable. Therefore, the base material preferably contains an alicyclic structure-containing polymer. When the alicyclic structure-containing polymer is used, advantages such as improvement of orientation, uniformity of orientation and surface shape of the liquid crystal cured film, and suppression of bright spots can be remarkably obtained. In addition, the alicyclic structure-containing polymer is excellent in transparency, low water absorption, moisture resistance, dimensional stability and light weight.

The alicyclic structure-containing polymer is a polymer containing an alicyclic structure, and examples thereof include a polymer obtained by a polymerization reaction using a cyclic olefin as a monomer or a hydride thereof. Preferred alicyclic structure-containing polymers include, for example, (1) norbornene-based polymer, (2) monocyclic cyclic olefin polymer, (3) cyclic conjugated diene polymer, and (4) vinyl alicyclic hydrocarbon. Polymers and hydrides thereof and the like can be mentioned. Among these, the norbornene-based polymer and its hydride are more preferable from the viewpoint of remarkably obtaining advantages such as improvement of orientation, uniformity of orientation and surface condition of the liquid crystal cured film, and suppression of bright spots.

Examples of the norbornene-based polymer include a ring-opened polymer of a norbornene-based monomer, a ring-opened copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization, and hydrides thereof; with a norbornene-based monomer. Examples thereof include a copolymer and an addition copolymer of a norbornene-based monomer and another copolymer copolymerizable. Among these, a ring-opening polymer hydride of a norbornene-based monomer is particularly preferable from the viewpoint of remarkably obtaining advantages such as improvement of orientation, orientation uniformity and surface condition of the liquid crystal cured film, and suppression of bright spots. The alicyclic structure-containing polymer is selected from, for example, the polymers disclosed in JP-A-2002-321302.

Examples of commercially available resins containing alicyclic structure-containing polymers include trade names "ZEONOR" (manufactured by Nippon Zeon), "Arton" (manufactured by JSR), "Apel" (manufactured by Mitsui Chemicals), and " The product group of "TOPAS" (manufactured by Polyplastics) can be mentioned.

The weight average molecular weight (Mw) of the polymer contained in the resin forming the base material is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, and preferably 100,000 or more. Below, it is more preferably 80,000 or less, and particularly preferably 50,000 or less. When a polymer having such a weight average molecular weight is used, the balance between mechanical strength, molding processability and heat resistance is good.

The molecular weight distribution (Mw / Mn) of the polymer contained in the resin forming the base material is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3. It is 5 or less, more preferably 3.4 or less, and particularly preferably 3.3 or less. When the molecular weight distribution is at least the lower limit of the above range, the productivity of the polymer can be increased and the production cost can be suppressed. Further, when the molecular weight distribution is not more than the upper limit value of the above range, the amount of the low molecular weight component becomes small, so that the relaxation at the time of high temperature exposure can be suppressed.

The weight average molecular weight Mw and the number average molecular weight Mn of the polymer are abbreviated as gel permeation chromatography (hereinafter, abbreviated as "GPC") using cyclohexane (toluene when the polymer is insoluble in cyclohexane) as a solvent. ), It can be measured in terms of polyisoprene (or polystyrene when the solvent is toluene).

One type of polymer may be used alone, or two or more types may be used in combination at any ratio.

The proportion of the polymer in the resin forming the base material is preferably 80% by weight to 100% by weight from the viewpoint of significantly improving the orientation, orientation uniformity and surface shape of the liquid crystal cured film, and suppressing bright spots. By weight%, more preferably 90% by weight to 100% by weight, still more preferably 95% by weight to 100% by weight, particularly preferably 98% by weight to 100% by weight.

The base material may contain any component in combination with the polymer. Optional components include, for example, inorganic fine particles; stabilizers such as antioxidants, heat stabilizers, ultraviolet absorbers, near-infrared absorbers; resin modifiers such as lubricants and plasticizers; colorants such as dyes and pigments. ; And antistatic agents. As these arbitrary components, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The substrate can have any shape with a surface to be rubbed. From the viewpoint of significantly improving orientation, orientation uniformity and surface shape, and suppressing bright spots, the surface to which the base material is rubbed is usually a flat surface without recesses and protrusions. Is preferable. Therefore, the shape of the base material is preferably a shape having such a flat surface, and particularly preferably a film shape from the viewpoint of handleability.

When the base material is in the form of a film, the thickness of the base material is not limited. From the viewpoint of improving the handleability of the base material, the thickness of the base material is preferably 10 μm or more, more preferably 20 μm or more, preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less.

Above all, from the viewpoint of enabling efficient production of the liquid crystal cured film by the roll-to-roll method, the base material is preferably elongated. In the following description, a long base material may be referred to as a "belt-shaped base material".

The surface of the base material may have an alignment film. The "alignment film" refers to a film having a function of orienting a liquid crystal compound contained in a layer of a liquid crystal composition formed on the surface of the film in a predetermined direction. Examples of the alignment film include a film formed of a resin such as polyvinyl alcohol, polyamide, and polyimide. In order to exert the orientation regulating force on the surface of the base material, it is preferable that the surface of the base material is subjected to a treatment for imparting the orientation regulating force. Examples of the treatment for applying the orientation regulating force include rubbing treatment and photoalignment treatment. From the viewpoint of exhibiting the effect by the subsequent cleaning process, the rubbing treatment is more preferable, and the base material preferably does not have an alignment film.

[3. Surface modification treatment]
Before the surface of the base material is subjected to the rubbing treatment, the surface of the base material may be subjected to a surface modification treatment capable of increasing the surface free energy of the surface. However, this surface modification treatment does not include the rubbing treatment. By performing such a surface modification treatment, the coating property of the liquid crystal composition on the surface of the base material can be improved. Therefore, it is possible to improve the adhesion of the liquid crystal composition to the surface of the base material and suppress the repelling of the liquid crystal composition. Further, in particular, when at least some molecules of the liquid crystal compound contained in the liquid crystal cured film are inclined with respect to the layer plane of the liquid crystal cured film, the liquid crystal compound is subjected to a surface modification treatment. The tilt angle of the molecule can be increased.

Examples of the surface modification treatment include corona treatment, plasma treatment, ultraviolet irradiation treatment and the like. Above all, the corona treatment is preferable from the viewpoint of effectively increasing the inclination angle of the molecules of the liquid crystal compound. Dose of corona discharge electron is preferably ^{1W / m 2 / min~1000W / m} 2 / min.

[4. Rubbing process]
The method for producing a liquid crystal cured film according to the present embodiment includes a step of preparing a base material and then applying a rubbing treatment to the surface of the base material. In the rubbing process, the surface of the base material is rubbed with an appropriate rubbing material. As a result, the orientation regulating force can be exerted on the surface of the rubbed base material. In the following description, the surface of the base material that has been subjected to the rubbing treatment may be referred to as a "rubbing treated surface".

The material of the rubbing material can be arbitrarily selected within a range in which a desired orientation regulating force can be obtained, and examples thereof include rayon; cotton; polyester and nylon blended woven fabrics.

The shape of the rubbing material can be arbitrarily selected within a range in which a desired orientation regulating force can be obtained. Examples of the shape include a roll shape, a rod shape, a block shape, and a sheet shape. Above all, a roll-shaped rubbing material is preferable because the rubbing treatment on the strip-shaped base material can be smoothly carried out. Hereinafter, the roll-shaped rubbing material may be referred to as a "rubbing roll".

When a rubbing treatment is performed on a strip-shaped base material using a rubbing roll, the rubbing roll usually rotates in contact with the strip-shaped base material at a holding angle of more than 0 ° to rub the surface of the strip-shaped base material. .. The hugging angle is preferably 5 ° or more, more preferably 10 ° or more, preferably 120 ° or less, and more preferably 90 ° or less. When the hugging angle is in this range, it is possible to develop a high orientation-regulating force without applying an undue load to the strip-shaped substrate.

The rubbing amount can be arbitrarily set within a range in which a desired orientation regulating force can be obtained. This rubbing amount is expressed by the relative moving distance of the contact surface of the rubbing material with respect to the base material (the surface of the rubbing material in contact with the base material) from the start of contact between the base material and the rubbing material to the end of contact. Can be done. Therefore, for example, when a rubbing treatment is performed on a strip-shaped base material using a rubbing roll, the amount of rubbing is the amount of the rubbing roll on the strip-shaped base material during the period from the start of contact between the strip-shaped base material and the rubbing roll to the end of contact. It can be expressed by the relative movement distance of the cylindrical surface. The range of suitable rubbing amounts can be 500 mm to 100,000 mm.

Normally, on the rubbing-treated surface of the base material, an orientation regulating force is generated to orient the molecules of the liquid crystal compound in a direction corresponding to the rubbing direction as the rubbing direction of the rubbing-treated surface. Therefore, it is desirable to set the rubbing direction according to the orientation direction required for the molecules of the liquid crystal compound contained in the liquid crystal curing film formed on the base material.

When a rubbing treatment is performed on a strip-shaped base material using a rubbing roll, the angle formed by the transport direction of the strip-shaped base material and the rotation axis of the rubbing roll is called a "swing angle". By appropriately adjusting the swing angle, the rubbing direction can be adjusted. The specific swing angle is usually set in an angle range larger than 0 ° and 90 ° or less. This angle range is preferably 10 ° or more, more preferably 35 ° or more, particularly preferably 40 ° or more, preferably 80 ° or less, more preferably 55 ° or less, and particularly preferably 50 ° or less. In the rubbing treatment of the strip-shaped base material, it is often required to perform the rubbing treatment so as to have an orientation regulating force in the direction of 45 ° with respect to the longitudinal direction of the strip-shaped base material. By setting the swing angle within the above-mentioned angle range, the rubbing process can be performed in the rubbing direction forming the above-mentioned angle with respect to the longitudinal direction of the strip-shaped base material, so that such an orientation regulating force in a desired direction can be exhibited. Easy to achieve.

When the strip-shaped base material is subjected to the rubbing treatment, the rubbing treatment is usually carried out while the strip-shaped base material is continuously conveyed in the longitudinal direction. At this time, the line speed and tension of the strip-shaped base material can be appropriately set to appropriate values according to the strip-shaped base material to be used, desired rubbing conditions, and the like. For example, the line speed can preferably be 1 m / min to 50 m / min. Further, the tension can be preferably 30 N / m to 500 N / m.

When a rubbing treatment is performed on a strip-shaped base material using a rubbing roll, it is desirable to adjust the rotation speed of the rubbing roll so as to obtain the above-mentioned preferable rubbing amount. Specifically, the rotation speed of the rubbing roll has a desired range of the rubbing amount calculated by the product of the peripheral speed of the cylindrical surface of the rubbing roll and the time when the rubbing roll is in contact with the strip-shaped base material. Can be adjusted. More specifically, the peripheral speed of the cylindrical surface of the rubbing roll is determined from the rubbing roll diameter d (mm) and the rotation speed t (rpm) at πdt / 60 (mm / sec), and the rubbing roll is a strip-shaped base material. The contact time is calculated from the line speed v (mm / min), the holding angle Aθw (°), and the swing angle φ (°) by (πdAθw / 360) ÷ (vsinφ / 60) (seconds). The product of is (π ² d ^{2 A} θ wt) / (360 vs in φ) (mm). Therefore, it is desirable to adjust the rotation speed of the rubbing roll so that the product falls within the above-mentioned preferable range of the rubbing amount.

There are no particular restrictions on the temperature conditions and atmosphere during the rubbing process. For example, the rubbing treatment can be performed at a temperature of 0 ° C. to 80 ° C. in an air or nitrogen atmosphere.

Hereinafter, an embodiment of a preferable rubbing process will be described with reference to the drawings. In the following description, "rotating" the "transport direction" means defining a curved transport path in which the transport direction changes as the strip-shaped substrate is transported downstream. For example, when the transport path is defined to be curved by the peripheral surface such as the cylindrical surface of the roll such as the rubbing roll and the free roll, and the curved transport surface of the floating transport device, the transport direction rotates. A device that supports a strip-shaped base material on a transport path, such as a roll or a floating transport device, may be simply referred to as a "support device".

Further, in the following description, when a support device is "immediately" upstream of the rubbing roll, the support device is located upstream of the rubbing roll and rotates in a transport direction between the support device and the rubbing roll. It means that there is no support device to make it. Similarly, when a support device is "immediately" downstream of the rubbing roll, the support device is located downstream of the rubbing roll, and a support device that rotates the transport direction between the support device and the rubbing roll. A state that does not exist.

In the drawings related to the rubbing process shown below, the coordinates are shown by the coordinate axes X, Y, and Z, which are common coordinate axes. In the example shown below, the coordinate axes X, Y and Z are coordinate axes orthogonal to each other, and the XY plane (plane parallel to both the coordinate axes X and Y) is a horizontal plane (that is, a plane orthogonal to the direction of gravity).

(First Embodiment of rubbing process)
1 to 3 are a side view, a top view, and a rear view schematically showing an example of a rubbing device according to an embodiment and an operation of a rubbing process using the rubbing device. In FIG. 1, the rubbing device A100 is observed from the coordinate axis Y direction, in FIG. 2, the rubbing device A100 is observed from the coordinate axis Z direction, and in FIG. 3, the rubbing device A100 is observed from the coordinate axis X direction. In the rubbing process according to this embodiment, the strip-shaped base materials (A11 to A16) carried in from the upstream of the transport path are brought into contact with the rubbing roll A130 rotating around the rotation shaft A13X and rubbed, and are rubbed downstream of the transport path. Carry out to.

The rubbing device A100 includes a rubbing roll A130, a free roll A110 immediately upstream thereof, and a free roll A150 immediately downstream thereof. In the operation of the rubbing device A100, the strip-shaped base materials (A11 to A16) are conveyed in the direction of arrow AR1.

The strip-shaped base material A11 carried into the rubbing device A100 is guided to proceed along the cylindrical surface of the upstream freeroll A110. Due to such guidance, the transport direction of the strip-shaped base material rotates at an angle exceeding 0 °. The free roll A110 is a transport roll installed in a state where it can freely rotate around the shaft A11X. Therefore, the free roll A110 rotates in the direction of arrow AR2 with the band-shaped base material to be conveyed.

Normally, the rotation axis of rotation in the transport direction by the free roll A110 coincides with the rotation axis A11X of the free roll A110 itself, and is orthogonal to the transport direction of the strip-shaped base material from the start of contact with the free roll A110 to the end of contact. .. In the example shown in this embodiment, the axis A11X of the freeroll A110 is parallel to the coordinate axis Y. The angle formed by the free roll A110 and the transport direction may have an error within ± 0.5 ° from the orthogonal angle as long as the transport is not hindered. In such a configuration, the free roll A110 can convey the strip-shaped base material in a gripped state.

When the transport device for transporting the strip-shaped base material "grips" and transports the strip-shaped base material as described above, the transport device has a movable peripheral surface and accompanies the movement of the peripheral surface. This is a mode in which the strip-shaped base material is transported, and when the strip-shaped base material is further transported, the strip-shaped base material does not slip with the peripheral surface of the transport device. Therefore, the free roll A110 is a device that conveys the strip-shaped base material in a gripped state, while the conveying devices such as the rubbing roll and the floating transport device are not devices that convey the strip-shaped base material in a gripped state. A roll capable of transporting the strip-shaped base material in a gripped state in this way may be hereinafter referred to as a "grip roll".

The strip-shaped base material A13 is transported downstream of the upstream free roll A110, and is subsequently guided to proceed along the cylindrical surface of the rubbing roll A130. In the example shown in this embodiment, the carry-in direction of the strip-shaped base material A13 is a horizontal direction, that is, a direction parallel to the XY plane. Further, the axis A13X of the rubbing roll A130 is parallel to the XY plane and is tilted at a predetermined swing angle with respect to the coordinate axis X. Unlike the free roll A110, the rubbing roll A130 is driven by a driving device (not shown) so as to rotate in the direction of arrow AR2 about the axis A13X, whereby the cylindrical surface of the rubbing roll A130 is one surface of the strip-shaped base material. Rubbing.

In the manufacturing method of Embodiment A, the rubbing roll A130 comes into contact with the strip-shaped base material at a holding angle of more than 0 °, thereby rotating the transport direction of the strip-shaped base material. By making contact at a hugging angle exceeding 0 ° in this way, the strip-shaped base material can be brought into contact with the rubbing roll A130 at a high pressure. Further, the transport direction of the strip-shaped base material and the rotation axis of the rubbing roll A130 may be orthogonal or non-orthogonal. The transport direction of the strip-shaped base material referred to here is the transport direction of the strip-shaped base material holding the rubbing roll. When the transport direction of the strip-shaped base material and the rotation axis of the rubbing roll A130 are orthogonal to each other, the rubbing process in the longitudinal direction by the rubbing roll A130 can be achieved. Further, when the transport direction of the strip-shaped base material and the rotation axis of the rubbing roll A130 are non-orthogonal, the rubbing process by the rubbing roll A130 in an oblique direction (that is, a direction that is neither parallel nor vertical to the longitudinal direction) is achieved. ..

The rubbed strip-shaped base material A14 is transported downstream of the rubbing roll A130, and is subsequently guided to proceed along the cylindrical surface of the downstream freeroll A150. Due to such guidance, the transport direction of the strip-shaped base material rotates at an angle exceeding 0 °. The free roll A150 is a transport roll installed in a state where it can freely rotate around the shaft A15X. Therefore, the free roll A150 rotates in the direction of arrow AR3 with the band-shaped base material to be conveyed.

In the example shown in this embodiment, the free roll A150 is a grip roll like the free roll A110, and the rotation axis of rotation in the transport direction by the free roll A150 coincides with the rotation axis A15X of the free roll A150 itself, and the free roll It is orthogonal to the transport direction of the strip-shaped base material from the start of contact with A150 to the end of contact.

After that, the strip-shaped base material A16 is sent downstream of the downstream freeroll A150 to obtain a rubbed strip-shaped base material.

In the rubbing treatment according to such an embodiment, the carrying direction of the strip-shaped base material at the position where the contact between the strip-shaped base material carried into the rubbing roll A130 and the rubbing roll A130 starts extends over the width direction of the strip-shaped base material. It is preferable that they are the same. Further, it is preferable that the carry-out direction of the band-shaped base material at the position where the contact between the band-shaped base material carried out from the rubbing roll A130 and the rubbing roll A130 ends is the same over the width direction of the band-shaped base material. This point will be described with reference to the drawings.

4 to 5 are side views schematically showing the relationship between the rubbing roll A130 and the strip-shaped base material in the rubbing apparatus A100 shown in FIGS. 1 to 3. In FIG. 4, the rubbing roll A130 is observed from its axis A13X direction, and in FIG. 5, the rubbing roll A130 is observed from the Y coordinate axis direction. In FIG. 4, both the strip-shaped base material A13 carried into the rubbing roll A130 and the strip-shaped base material A14 carried out from the rubbing roll A130 are illustrated, but in FIG. 5, for convenience of illustration, the strip-shaped base material is shown. Only A14 is shown.

In the example shown in FIG. 4, the strip-shaped base material A13 carried into the rubbing roll A130 advances in the carrying-in direction indicated by the arrow AR13, and starts contact with the rubbing roll A130 at the position A131. Therefore, the carry-in direction of the band-shaped base material at the position where the contact between the band-shaped base material carried into the rubbing roll and the rubbing roll starts is the direction indicated by the arrow AR13.

After that, the strip-shaped base material holds the rubbing roll A130 at the holding angle Aθw and ends the contact with the rubbing roll A130 at the position A132. Then, the strip-shaped base material A14 carried out from the rubbing roll A130 proceeds in the carry-out direction indicated by the arrow AR14. Therefore, the carry-out direction of the band-shaped base material at the position where the contact between the band-shaped base material carried out from the rubbing roll and the rubbing roll ends is the direction indicated by the arrow AR14.

At this time, the carry-out direction indicated by the arrow AR14 is preferably the same over the width direction of the strip-shaped base material A14. That is, as shown in FIG. 5, the carry-out direction of the strip-shaped base material A14 carried out from the rubbing roll A130 at the position A132 is the direction indicated by arrows AR14-1 to AR14-5, respectively, over the width direction. Is preferably in the same direction. Further, it is preferable that the carry-in direction indicated by the arrow AR13 is also the same over the width direction of the strip-shaped base material A13. Here, the fact that the carry-in direction or the carry-out direction is "same" over the width direction may include an error. For example, the carry-in or carry-out direction at the center in the strip-shaped base material width direction (in the example of FIG. 5). With reference to the carry-out direction indicated by the arrow AR14-3, a direction having an angle of 0.5 ° or less with the reference direction may be set as the “same” direction.

As a result, it is possible to achieve rubbing in which the length of the transport path of the strip-shaped base material is uniform over the width direction of the strip-shaped base material. Therefore, the strip-shaped base material can be brought into contact with the rubbing roll A130 with a uniform pressure without twisting, and the degree of the rubbing treatment of the strip-shaped base material can be made uniform in the width direction of the strip-shaped base material.

(Second embodiment of rubbing process)
6 to 7 are a side view and a top view schematically showing an example of a rubbing device according to another embodiment and an operation of a rubbing process using the rubbing device. In FIG. 6, the rubbing device C100 is observed from the coordinate axis Y direction, and in FIG. 7, the rubbing device C100 is observed from the coordinate axis Z direction. In the rubbing process according to this embodiment, the strip-shaped base materials (C11 to C16) carried in from the upstream of the transport path are brought into contact with the rubbing roll C130 rotating around the rotation shaft C13X and rubbed, and are rubbed downstream of the transport path. Carry out to.

The rubbing device C100 includes a rubbing roll C130, a freeroll C110 on the upstream side thereof, and a freeroll C150 on the downstream side thereof. The rubbing device C100 further includes a levitation transfer device C120 between the rubbing roll C130 and the free roll C110, and a levitation transfer device C140 between the rubbing roll C130 and the free roll C150. In the operation of the rubbing device C100, the strip-shaped base materials (C11 to C16) are conveyed in the direction of arrow CR1.

The strip-shaped base material C11 carried into the rubbing device C100 is guided to proceed along the cylindrical surface of the upstream freeroll C110. At this time, the free roll C110 is accompanied by the band-shaped base material to be conveyed and rotates in the direction of arrow CR3. Normally, the rotation axis of rotation in the transport direction by the free roll C110 coincides with the rotation axis C11X of the free roll C110 itself, and is orthogonal to the transport direction of the strip-shaped base material from the start of contact with the free roll C110 to the end of contact. .. In the example shown in this embodiment, the axis C11X of the freeroll C110 is parallel to the coordinate axis Y. The angle formed by the free roll C110 and the transport direction may have an error within ± 0.5 ° from the orthogonal angle as long as the transport is not hindered. In such a configuration, the free roll C110 can convey the strip-shaped base material in a gripped state.

The strip-shaped base material C12 is transported downstream of the upstream free roll C110, and subsequently guided to proceed along the transport surface of the levitation transport device C120, and the transport direction is rotated. In the example shown in this embodiment, the carry-in direction of the strip-shaped base material C12 is a horizontal direction, that is, a direction parallel to the XY plane. Further, the axis C12X of the levitation transfer device C120 is parallel to the XY plane and is inclined at an angle of 45 ° with respect to the coordinate axis Y.

The levitation transfer device C120 will be described more specifically with reference to FIGS. 10 to 12. 10 to 12 are a perspective view, a side view, and a bottom view schematically showing the levitation transport device C120 in the rubbing device C100 shown in FIGS. 6 and 7. As shown in FIGS. 10 to 12, the levitation transport device C120 includes a transport section C123 having a transport surface C123S and an air introduction section C124 (not shown in FIGS. 6 and 7). The air introduction unit C124 includes a device (not shown) for introducing pressurized air into the transport unit C123 in a pressure-adjustable manner. The transport portion C123 has a semi-cylindrical shape with the shaft C12X as the axis, and the transport surface C123S has a curved surface along the cylindrical shape. The transport surface C123S of the transport section C123 is provided with a large number of holes and communicates with the air introduction section so that the air introduced from the air introduction section C124 can be ejected.

In the use of the levitation transport device C120, the strip-shaped base material is guided onto the transport surface C123S in a tense state by being pulled in the direction of arrow CR4. Due to this tension, the strip-shaped substrate is urged in the direction of arrow CR5. On the other hand, the strip-shaped base material is urged in the direction of arrow CR6 by ejecting air from the holes of the transport surface C123S. By appropriately adjusting the pressure of the air ejection, it is possible to balance the urging due to the tension of the strip-shaped base material and the urging due to the air ejection, and as a result, between the strip-shaped base material and the levitation transport device C120. An air layer is formed by the air pressure of the supplied air, and the strip-shaped base material can be floated and transported along the transport surface C123S in a non-contact state with the transport surface C123S. As a result of such levitation transport, transport accompanied by rotation in the transport direction with the shaft C12X as the rotation axis direction becomes possible. In addition, since the strip-shaped base material is not in contact with the transport surface C123S, it is possible to transport the strip-shaped base material in the direction parallel to the axis C12X (the direction indicated by the arrow CR7 in FIG. 12). As a result of being able to transport in the CR4 direction and the CR7 direction, it is possible to transport the strip-shaped base material in the diagonal transport direction indicated by the arrow CR1 in FIG. 12, which is a direction non-orthogonal to the axis C12X.

As shown in FIGS. 6 and 7, the strip-shaped base material C13 is transported downstream of the levitation transport device C120, and is subsequently guided to proceed along the cylindrical surface of the rubbing roll C130. In the example shown in this embodiment, the axis C13X of the rubbing roll C130 is parallel to the XY plane and is tilted at an angle of 45 ° with respect to the coordinate axis Y. Unlike the free roll C110, the rubbing roll C130 is driven by a driving device (not shown) so as to rotate in the direction of arrow CR2 about the axis C13X, whereby the cylindrical surface of the rubbing roll C130 is one surface of the strip-shaped base material. Rubbing.

The rubbed strip-shaped base material C14 is transported downstream of the rubbing roll C130, and is subsequently guided to proceed along the transport surface of the levitation transport device C140, and the transport direction is rotated. The levitation transfer device C140 is the same device as the levitation transfer device C120. Similar to the levitation transfer device C120, the levitation transfer device C140 has its axis C14X parallel to the XY plane and is tilted at an angle of 45 ° with respect to the coordinate axis Y. The carried-out direction of the rubbed strip-shaped base material C15 carried out from the levitation transport device C140 is a direction parallel to the XY plane.

The rubbed strip-shaped base material C15 is transported downstream of the levitation transport device C140, and is subsequently guided to proceed along the cylindrical surface of the downstream freeroll C150. The free roll C150 is a transport roll installed so as to be able to freely rotate around the shaft C15X. Therefore, the free roll C150 rotates in the direction of arrow CR3 with the band-shaped base material to be conveyed.

In the example shown in this embodiment, the free roll C150 is a grip roll like the free roll C110, and the rotation axis of rotation in the transport direction by the free roll C150 coincides with the rotation axis C15X of the free roll C150 itself. It is orthogonal to the transport direction of the strip-shaped base material from the start of contact with C150 to the end of contact. In this example, the axis C15X of the freeroll C150 is parallel to the coordinate axis Y.

After that, the strip-shaped base material C16 is transported downstream of the downstream freeroll C150 to obtain a rubbed strip-shaped base material.
In the rubbing process according to such an embodiment, the carrying direction of the strip-shaped base material at the position where the contact between the strip-shaped base material carried into the rubbing roll C130 and the rubbing roll C130 starts extends over the width direction of the strip-shaped base material. It is preferable that they are the same. Further, it is preferable that the carry-out direction of the band-shaped base material at the position where the contact between the band-shaped base material carried out from the rubbing roll C130 and the rubbing roll C130 ends is the same over the width direction of the band-shaped base material. This point will be described with reference to the drawings.

FIG. 8 is a side view schematically showing the relationship between the floating transfer device C120, the rubbing roll C130, the floating transfer device C140, and the strip-shaped base material in the rubbing device C100 shown in FIGS. 6 to 7, and FIG. 9 is a side view schematically showing the relationship between the rubbing roll. It is a side view which shows roughly the relationship between C130 and the strip-shaped base material C14 carried out from there. In FIG. 8, the rubbing roll C130 is observed from the axis C13X direction thereof, and in FIG. 9, the rubbing roll C130 is observed from the Y coordinate axis direction.

In the examples of FIGS. 8 to 9, the strip-shaped base material C13 that leaves the levitation transport device C120 and is carried into the rubbing roll C130 advances in the carry-in direction indicated by the arrow CR13 and starts contact with the rubbing roll C130 at the position C131. To do. Therefore, the carry-in direction of the band-shaped base material at the position where the contact between the band-shaped base material carried into the rubbing roll and the rubbing roll starts is the direction indicated by the arrow CR13.

After that, the strip-shaped base material holds the rubbing roll C130 at the holding angle Cθw13, and ends the contact with the rubbing roll C130 at the position C132. Then, the strip-shaped base material C14 carried out from the rubbing roll C130 proceeds in the carrying-out direction indicated by the arrow CR14. Therefore, the carry-out direction of the band-shaped base material at the position where the contact between the band-shaped base material carried out from the rubbing roll and the rubbing roll ends is the direction indicated by the arrow CR14.

Further, the carry-out direction indicated by the arrow CR14 is the same over the width direction of the strip-shaped base material C14. That is, as shown in FIG. 9, the carry-out direction of the strip-shaped base material C14 carried out from the rubbing roll C130 at the position C132 is the direction exemplified by the arrows CR14-1 to CR14-5 over the width direction, respectively. These are preferably in the same direction. Further, it is preferable that the carry-in direction indicated by the arrow CR13 is also the same over the width direction of the strip-shaped base material C13. Here, the fact that the carry-in direction or the carry-out direction is "same" over the width direction may include an error. For example, the carry-in or carry-out direction at the center in the strip-shaped base material width direction (in the example of FIG. 9). With reference to the carry-out direction indicated by the arrow CR14-3, a direction in which the angle formed with the reference direction is within 0.5 ° may be regarded as the “same” direction.

As a result, the strip-shaped base material can be brought into contact with the rubbing roll C130 at a uniform pressure without twisting, and the degree of rubbing treatment of the strip-shaped base material can be made uniform in the width direction of the strip-shaped base material. .. In addition, the carry-out direction of the strip-shaped base material C16 carried out from the rubbing device C100 is not skewed with respect to the carry-in direction of the strip-shaped base material C11 carried into the rubbing device C100. The "skew" here is a relationship between the carry-in direction and the carry-out direction, which cannot be corrected to a parallel relationship by the grip roll. By setting the direction of the carry-out direction with respect to the carry-in direction to a direction in which the amount of skew is small in this way, it is possible to carry out low-cost manufacturing without deriving wrinkles and scratches.

Further, in the present embodiment, it is preferable that the rotation axis direction of the rotation of the strip-shaped base material by the transfer device in the transfer direction is parallel to the rotation axis of the rubbing roll C130. Specifically, it is preferable that the rotation axis direction of the rotation of the strip-shaped base material in the transport direction by the floating transport devices C120 and C140 immediately upstream and immediately downstream of the rubbing roll C130 is parallel to the rotation axis of the rubbing roll. This makes it easy to make the carry-in direction to the rubbing roll C130 and the carry-out direction from the rubbing roll C130 the same over the width direction of the strip-shaped base material. Here, the fact that the rotation axis direction of rotation in the transfer direction by the transfer device and the rotation axis of the rubbing roll C130 are "parallel" may include an error, for example, the angle formed by these is 0.5. The direction within ° may be the "parallel" direction.

Further, in the rubbing device C100 according to the present embodiment, it is preferable that the total rotation angle of the rotation of the strip-shaped base material in the transport direction by the rubbing roll C130 and the rotation angle of the rotation in the transport direction by the transport device is approximately 0 °. .. To explain this point with reference to FIG. 8 again, the strip-shaped base material C12 carried into the levitation transport device C120 is transported in an angle Cθw12 from the position C121 to the position C122 by the rotation process by the levitation transport device C120. Rotate with. The strip-shaped base material C13 carried out downstream of the levitation transport device C120 is subsequently rotated in the transport direction at an angle Cθw13 from the position C131 to the position C132 by the rubbing step by the rubbing roll C130. The strip-shaped base material C14 carried out downstream of the rubbing roll C130 is subsequently rotated in the transport direction from position C141 to position C142 at an angle Cθw14 by a rotation step by the levitation transport device C140. Since the direction of rotation by the levitation transport devices C120 and C140 is opposite to the direction of rotation by the rubbing roll C130, the rotation angles of these can be calculated by summing them with one as positive and the other as negative. The sum is required. For example, by setting Cθw12 = Cθw14 = 30 ° and Cθw13 = 60 °, the sum of these becomes 0 °. By setting the total rotation angle to approximately 0 °, it is possible to easily obtain a transport path in which the carry-out direction does not skew with respect to the carry-in direction. Therefore, even if the holding angle Cθw13 of the rubbing roll is increased, the rubbing process having a uniform degree can be performed more easily in a state where the carry-out direction is not skewed with respect to the carry-in direction.

The total rotation angle of "substantially" 0 ° includes not only the case where it is exactly 0 ° but also the case where it has a tolerance. Specifically, the value may exceed 0 ° as long as the skew can be easily corrected by a device such as EPC (registered trademark) that can correct the skew. Specifically, the range may be preferably 5 ° or less, more preferably 2 ° or less.

[5. Cleaning process]
The method for producing a liquid crystal cured film according to the present embodiment includes a step of rubbing the surface of the base material and then cleaning the rubbing treated surface of the base material with a solvent. In the following description, the solvent used for cleaning the rubbing-treated surface may be referred to as a "cleaning solution".

Foreign matter such as fine dust may be generated on the rubbing surface of the base material due to friction during rubbing, and the foreign matter may adhere to the surface. This foreign matter can cause bright spots in the liquid crystal cured film. However, since the foreign matter can be removed by washing, the liquid crystal cured film in which the generation of bright spots is suppressed can be produced according to the production method according to the present embodiment.
Further, by cleaning the rubbing-treated surface with a cleaning liquid, surprisingly, the orientation of the produced liquid crystal cured film can be improved.

The cleaning liquid preferably has an SP value in a predetermined range. The SP value means the Hildebrand solubility parameter (Hildebrand solubility parameter). This SP value can be calculated by the SP value calculation software "HSPiP ver. 4.1.7" (http://www.hansen-solubility.com/index.html).

The specific SP value of the cleaning liquid is preferably 12 or more, preferably 24 or less. When the SP value of the cleaning liquid is not less than the lower limit value and not more than the upper limit value of the above range, the orientation and surface shape of the liquid crystal cured film can be effectively improved.

The difference between the SP value of the cleaning liquid and the SP value of the base material is preferably within a predetermined range. Here, the SP value of the base material represents the SP value of the material of the base material, and specifically represents the SP value of the material forming the rubbing treated surface of the base material. The specific difference between the SP value of the cleaning liquid and the SP value of the base material is preferably 1.5 or more, more preferably 2 or more, and particularly preferably 4 or more. When the difference between the SP value of the cleaning liquid and the SP value of the base material is within the above range, the dissolution of the base material by the cleaning liquid can be suppressed, so that the liquid crystal cured film can be smoothly produced. The upper limit of the difference between the SP value of the cleaning liquid and the SP value of the base material is not particularly limited, but may be 16 or less, for example.

Preferred cleaning solutions include, for example, water; an alcohol solvent such as ethanol; a ketone solvent such as acetone and cyclopentanone; an ether solvent such as dioxolane; a cyan solvent such as acetonitrile; an amide solvent such as dimethylformamide; a glycol solvent such as ethylene glycol. Aromatic hydrocarbon solvents such as phenol; and the like.

One type of cleaning liquid may be used alone, or two or more types may be used in combination at an arbitrary ratio.

Cleaning is usually performed by bringing the rubbing surface of the base material into contact with the cleaning liquid. The specific cleaning method is not limited, and for example, the cleaning liquid may be sprayed onto the rubbing surface of the base material for cleaning. However, from the viewpoint of efficient cleaning, it is preferable to perform cleaning by immersing the base material in the cleaning liquid stored in the liquid tank. For example, when a strip-shaped base material is used, efficient cleaning can be performed by transporting the strip-shaped base material so as to pass through the cleaning liquid stored in the liquid tank.

At the time of cleaning, it is preferable that the rubbing surface of the base material is in contact with the cleaning liquid for a predetermined time. Thereby, the action of the rubbing-treated surface for improving the orientation of the liquid crystal cured film can be enhanced. The specific contact time between the rubbing surface and the cleaning liquid is preferably 1 second or longer, more preferably 10 seconds or longer, preferably 60 seconds or shorter, and more preferably 30 seconds or shorter.

The temperature of the cleaning liquid is not particularly limited. The temperature of the cleaning liquid used at the time of cleaning can be, for example, 0 ° C to 80 ° C.

[6. Solvent removal]
After cleaning the rubbing-treated surface of the base material, a treatment for removing the cleaning liquid adhering to the rubbing-treated surface may be performed before forming a layer of the liquid crystal composition on the rubbing-treated surface. The specific removal method is arbitrary. For example, a gas such as air may be injected onto the rubbing surface to remove the cleaning liquid by blowing it off the rubbing surface. Further, for example, the cleaning liquid may be dried to remove the cleaning liquid from the rubbing-treated surface. The drying method is not limited, and for example, a method such as natural drying, heat drying, vacuum drying, and vacuum heating drying can be adopted.

[7. Step of forming a layer of liquid crystal composition]
The method for producing a liquid crystal cured film according to the present embodiment includes a step of forming a layer of a liquid crystal composition on the rubbing-treated surface of the base material after cleaning the rubbing-treated surface.

The liquid crystal composition is a composition containing a reverse dispersion liquid crystal compound. This liquid crystal composition includes not only a material containing two or more kinds of components but also a material containing only one kind of inversely dispersed liquid crystal compound.

Since the inversely dispersed liquid crystal compound has a liquid crystal property, it can usually exhibit a liquid crystal phase when the inversely dispersed liquid crystal compound is oriented.

As described above, the inversely dispersed liquid crystal compound is a liquid crystal compound capable of exhibiting inverse wavelength dispersive birefringence. A liquid crystal compound capable of exhibiting reverse wavelength-dispersible birefringence is a liquid crystal that exhibits reverse wavelength-dispersible birefringence when a layer of the liquid crystal compound is formed and the liquid crystal compound is oriented in the layer. A sex compound. Usually, when the liquid crystal compound is homogenically oriented, the wavelength dispersibility of the birefringence exhibited by the layer of the liquid crystal compound can be examined to confirm the wavelength dispersibility of the birefringence exhibited by the liquid crystal compound. Here, homogenically orienting a liquid crystal compound means forming a layer containing the liquid crystal compound, and setting the direction of the maximum refractive index in the refractive index ellipse of the molecule of the liquid crystal compound in the layer of the layer. Orientation in one direction parallel to the plane. Further, the birefringence of the layer is obtained from "(in-plane retardation of the layer) ÷ (thickness of the layer)".

The birefringence of the reverse-dispersed liquid crystal compound is the refractive index of the molecule of the reverse-dispersed liquid crystal compound in the direction showing the maximum refractive index and the refractive index in another direction intersecting this direction. It can be expressed as a difference. Further, the wavelength dispersibility of the refractive index in each of the above-mentioned directions may differ depending on the molecular structure of the inversely dispersed liquid crystal compound. For example, a reverse-dispersed liquid crystal compound has a relatively large refractive index. In a certain direction, the refractive index measured at a long wavelength is smaller than the refractive index measured at a short wavelength, but the difference between them is small. On the other hand, in another direction where the refractive index is relatively small, the refractive index measured at the long wavelength is smaller than the refractive index measured at the short wavelength, and the difference between them is large. In the liquid crystal compound of such an example, the difference in refractive index between the directions is small when the measurement wavelength is short, and large when the measurement wavelength is long. As a result, this inversely dispersed liquid crystal compound can exhibit birefringence of inverse wavelength dispersibility.

The inversely dispersed liquid crystal compound preferably has polymerizable property. Therefore, it is preferable that the molecule of the inversely dispersed liquid crystal compound contains a polymerizable group such as an acryloyl group, a methacryloyl group, and an epoxy group. The number of polymerizable groups per molecule of the inversely dispersed liquid crystal compound may be one, but is preferably two or more. The polymerizable reverse-dispersed liquid crystal compound can be polymerized in a state of exhibiting a liquid crystal phase, and can be a polymer while maintaining the molecular orientation state in the liquid crystal phase. Therefore, it is possible to fix the orientation state of the back-dispersed liquid crystal compound in the liquid crystal cured film and to increase the degree of polymerization of the back-dispersed liquid crystal compound to increase the mechanical strength of the liquid crystal cured film.

The molecular weight of the inversely dispersed liquid crystal compound is preferably 300 or more, more preferably 500 or more, particularly preferably 800 or more, preferably 2000 or less, more preferably 1700 or less, and particularly preferably 1500 or less. When a inversely dispersed liquid crystal compound having a molecular weight in such a range is used, the coatability of the liquid crystal composition can be particularly improved.

The birefringence Δn of the inversely dispersed liquid crystal compound at the measurement wavelength of 590 nm is preferably 0.01 or more, more preferably 0.03 or more, preferably 0.15 or less, and more preferably 0.10 or less. When a inversely dispersed liquid crystal compound having a birefringence Δn in such a range is used, it is easy to obtain a liquid crystal cured film having few orientation defects.

The birefringence of the liquid crystal compound can be measured by, for example, the following method.
A layer of the liquid crystal compound is prepared, and the liquid crystal compound contained in the layer is homogenically oriented. Then, the in-plane retardation of the layer is measured. Then, the birefringence of the liquid crystal compound can be obtained from "(in-plane retardation of the layer) ÷ (thickness of the layer)". At this time, in order to facilitate in-plane retardation and thickness measurement, the homogenically oriented liquid crystal compound layer may be cured.

As the inverse dispersion liquid crystal compound, one kind may be used alone, or two or more kinds may be used in combination at an arbitrary ratio.

The back-dispersion liquid crystal compound is one or more in the molecule of the back-dispersion liquid crystal compound from the viewpoint of remarkably obtaining advantages such as improvement of orientation, orientation uniformity and surface condition of the liquid crystal cured film, and suppression of bright spots. It is preferable to have a benzothiazole ring of.

Specific examples of the inversely dispersed liquid crystal compound include a liquid crystal compound represented by the following formula (I).

In the formula (I), Ar represents a group represented by any of the following formulas (II-1) to (II-7). In formulas (II-1) to (II-7), * represents the bonding position with Z ¹ or Z ² .

In the above formula (II-1) ~ formula (II-7), ^{E 1} and ^{E 2,} each ^{independently, -CR 11 R 12 -, -} S -, - NR 11 -, - CO- and - Represents a group selected from the group consisting of O−. Further, R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Above all, it is preferable that E ¹ and E ² are independently of −S−.

In the above formulas (II-1) to (II-7), D ^{1 to} D ³ each independently have an aromatic hydrocarbon group or a substituent which may have a substituent. Represents an aromatic heterocyclic group which may be used. The number of carbon atoms of the group represented by D ^{1 to} D ³ (including the number of carbon atoms of the substituent) is usually 2 to 100 independently of each other.

The number of carbon atoms of the aromatic hydrocarbon group in D ^{1 to} D ³ is preferably 6 to 30. Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms in D ^{1 to} D ³ include a phenyl group and a naphthyl group. Among them, the phenyl group is more preferable as the aromatic hydrocarbon group.

Examples of the substituent that the aromatic hydrocarbon group in D ^{1 to} D ³ can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a number of carbon atoms such as a methyl group, an ethyl group and a propyl group. Alkyl groups 1 to 6; alkenyl groups having 2 to 6 carbon atoms such as vinyl groups and allyl groups; alkyl halides having 1 to 6 carbon atoms such as trifluoromethyl groups; dimethylamino groups and the like. N, N-dialkylamino group with 2 to 12 carbon atoms; alkoxy group with 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group; nitro group; -OCF ₃ ; -C (= O) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; and the like. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

^Ra may have an alkyl group having 1 to 6 carbon atoms; an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as a substituent, and has 6 carbon atoms. Represents a group selected from the group consisting of ~ 20 aromatic hydrocarbon groups;

R ^b may have an alkyl group having 1 to 20 carbon atoms which may have a substituent; an alkenyl group having 2 to 20 carbon atoms which may have a substituent; even if it has a substituent. It represents a group selected from the group consisting of a good cycloalkyl group having 3 to 12 carbon atoms; and an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent.

The number of carbon atoms of the alkyl group having 1 to 20 carbon atoms in R ^b is preferably 1 to 12, and more preferably 4 to 10. Examples of the alkyl group having 1 to 20 carbon atoms in R ^b include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a 1-methylpentyl group, and a 1-ethylpentyl group. , Se-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-Undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecil group, and n-icosyl group. And so on.

Examples of the substituent that the alkyl group having 1 to 20 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; and a dimethylamino group having 2 to 12 carbon atoms. N, N-dialkylamino group; alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group, etc., having 1 to 12 carbon atoms An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group; a nitro group; an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; a triazolyl group, a pyrrolyl group, a furanyl group and a thienyl group. Aromatic heterocyclic group having 2 to 20 carbon atoms such as group, thiazolyl group and benzothiazole-2-ylthio group; cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group. Cycloalkyloxy group having 3 to 8 carbon atoms such as cyclopentyloxy group and cyclohexyloxy group; Cyclic ether group having 2 to 12 carbon atoms such as tetrahydrofuranyl group, tetrahydropyranyl group, dioxolanyl group and dioxanyl group An aryloxy group having 6 to 14 carbon atoms such as a phenoxy group and a naphthoxy group; one or more hydrogen atoms such as a trifluoromethyl group, a pentafluoroethyl group and -CH ₂ CF ₃ are replaced with a fluorine atom. Fluoroalkyl groups having 1 to 12 carbon atoms; benzofuryl group; benzopyranyl group; benzodioxolyl group; and benzodioxanyl group; and the like can be mentioned. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The number of carbon atoms of the alkenyl group having 2 to 20 carbon atoms in R ^b is preferably 2 to 12. Examples of the alkenyl group having 2 to 20 carbon atoms in R ^b include a vinyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a decenyl group and an undecenyl group. , Dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadesenyl group, icosenyl group and the like.

Examples of the substituent which may have an alkenyl group having 2 to 20 carbon atoms in R ^b, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^b. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the cycloalkyl group having 3 to 12 carbon atoms in R ^b include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Of these, as the cycloalkyl group, a cyclopentyl group and a cyclohexyl group are preferable.

Examples of the substituent that the cycloalkyl group having 3 to 12 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; and a dimethylamino group having 2 to 12 carbon atoms. N, N-dialkylamino group; alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group; alkoxy having 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, etc. Examples thereof include a nitro group; an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; and the like. Among them, as the substituent of the cycloalkyl group, a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group; a methoxy group and an ethoxy group. An alkoxy group having 1 to 6 carbon atoms such as a group and an isopropoxy group; a nitro group; and an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms in R ^b include a phenyl group, a 1-naphthyl group, a 2-naphthyl group and the like. Of these, a phenyl group is preferable as the aromatic hydrocarbon group.

Examples of the substituent that the aromatic hydrocarbon group having 6 to 12 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; and a dimethylamino group having 2 carbon atoms. ~ 12 N, N-dialkylamino groups; alkoxy groups having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group, etc., having 1 carbon atom number An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group of ~ 12; a nitro group; an aromatic heterocyclic group having 2 to 20 carbon atoms such as a triazolyl group, a pyrrolyl group, a furanyl group, and a thiophenyl group; cyclo Cycloalkyl group having 3 to 8 carbon atoms such as propyl group, cyclopentyl group and cyclohexyl group; cycloalkyloxy group having 3 to 8 carbon atoms such as cyclopentyloxy group and cyclohexyloxy group; tetrahydrofuranyl group and tetrahydropyrani Cyclic ether group having 2 to 12 carbon atoms such as ru group, dioxolanyl group and dioxanyl group; aryloxy group having 6 to 14 carbon atoms such as phenoxy group and naphthoxy group; trifluoromethyl group and pentafluoroethyl group , -CH ₂ CF _3, etc., a fluoroalkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom; -OCF ₃ ; benzofuryl group; benzopyranyl group; benzodioxoryl group; benzo Dioxanyl group; etc. Among them, as the substituent of the aromatic hydrocarbon group, an alkoxy having 1 to 20 carbon atoms such as a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a methoxy group, an ethoxy group, an isopropoxy group and a butoxy group. Group; Nitro group; Aromatic heterocyclic group having 2 to 20 carbon atoms such as furanyl group and thiophenyl group; Cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group; Tri A fluoroalkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom, such as a fluoromethyl group, a pentafluoroethyl group, and -CH ₂ CF ₃ , -OCF ₃ ; is preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The number of carbon atoms of the aromatic heterocyclic group in D ^{1 to} D ³ is preferably 2 to 30. Examples of the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ include 1-benzofuranyl group, 2-benzofuranyl group, imidazolyl group, indolinyl group, frazayl group, oxazolyl group, quinolyl group and thiadiazolyl group. , Thiazolyl group, thiazolopyrazinyl group, thiazolopyridyl group, thiazolopyridazinyl group, thiazolopyrimidinyl group, thienyl group, triazinyl group, triazolyl group, naphthyldinyl group, pyrazinyl group, pyrazolyl group, pyranyl group, Pyridyl group, pyridazinyl group, pyrimidinyl group, pyrrolyl group, phthalazinyl group, furanyl group, phthalimide group, benzo [c] thienyl group, benzo [b] thienyl group, benzoisooxazolyl group, benzoisothiazolyl group, benzoimidazolyl group , Benzoxaziazolyl group, benzoxazolyl group, benzothiadiazolyl group, benzothiazolyl group, benzotriazinyl group, benzotriazolyl group, benzopyrazolyl group and the like. Among them, as the aromatic heterocyclic group, a monocyclic aromatic heterocyclic group such as a furanyl group, a pyranyl group, a thienyl group, an oxazolyl group, a frazanyl group, a thiazolyl group, and a thiadiazolyl group; Zolyl group, quinolyl group, 1-benzofuranyl group, 2-benzofuranyl group, phthalimide group, benzo [c] thienyl group, benzo [b] thienyl group, thiazolopyridyl group, thiazolopyrazinyl group, benzoisooxazoli Aromatic heterocyclic groups of fused rings, such as a ru group, a benzoxaziazolyl group, and a benzothiadiazolyl group;

Examples of the substituent which may have an aromatic heterocyclic group in D ¹ to D ^3, for example, include the same examples as the substituent group which may have an aromatic hydrocarbon group in D ¹ to D ^3. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the above formulas (II-1) to (II-7), D ^{4 to} D ⁵ each independently represent an acyclic group which may have a substituent. D ⁴ and D ⁵ may be combined to form a ring. The number of carbon atoms of the group represented by D ^{4 to} D ⁵ (including the number of carbon atoms of the substituent) is usually 1 to 100 independently of each other.

The number of carbon atoms of the acyclic group in D ^{4 to} D ⁵ is preferably 1 to 13. Examples of the acyclic group in D ^{4 to} D ⁵ include an alkyl group having 1 to 6 carbon atoms; a cyano group; a carboxyl group; a fluoroalkyl group having 1 to 6 carbon atoms; and an alkoxy group having 1 to 6 carbon atoms. -C (= O) -CH ₃ ; -C (= O) NHPh; -C (= O) -OR ^x ; Among them, as the acyclic group, a cyano group, a carboxyl group, -C (= O) -CH ₃ , -C (= O) NHPh, -C (= O) -OC ₂ H ₅ , -C (= O) -OC ₄ H ₉ , -C (= O) -OCH (CH ₃ ) ₂ , -C (= O) -OCH ₂ CH ₂ CH (CH ₃ ) -OCH ₃ , -C (= O) -OCH ₂ CH ₂ C (CH ₃ ) _2- OH and -C (= O) -OCH ₂ CH (CH ₂ CH ₃ ) -C ₄ H ₉ are preferable. The Ph represents a phenyl group. Further, R ^x represents an organic group having 1 to 12 carbon atoms. Specific examples of R ^x include an alkoxy group having 1 to 12 carbon atoms or an alkyl group having 1 to 12 carbon atoms which may be substituted with a hydroxyl group.

Examples of the substituent that the acyclic group in D ^{4 to} D ⁵ can have include the same example as the substituent that the aromatic hydrocarbon group in D ^{1 to} D ³ can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

When D ⁴ and D ⁵ are combined to form a ring, the above D ⁴ and D ⁵ form an organic group containing a ring. Examples of this organic group include a group represented by the following formula. In the following formula, * represents the position of the carbon to which D ⁴ and D ⁵ are bonded.

R ^* represents an alkyl group having 1 to 3 carbon atoms.
R ^** represents a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms and a phenyl group which may have a substituent.
R ^*** represents a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms and a phenyl group which may have a substituent.
R ^*** represents a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, and −COOR ¹³ . R ¹³ represents an alkyl group having 1 to 3 carbon atoms.
Examples of the substituent that the phenyl group can have include a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, a hydroxyl group, a carboxyl group, an alkoxy group, an aryloxy group, an acyloxy group, a cyano group and an amino group. Can be mentioned. Of these, as the substituent, a halogen atom, an alkyl group, a cyano group and an alkoxy group are preferable. The number of substituents contained in the phenyl group may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the above formulas (II-5) to (II-7), D ⁶ is -C (R ^f ) = N-N (R ^g ) R ^h , -C (R ^f ) = N-N = C. ^(R g) ^{R h,} and ^represents a group selected from the group consisting of -C (R f) = N- N = R i. The number of carbon atoms of the group represented by D ⁶ (including the number of carbon atoms of the substituent) is usually 3 to 100.

R ^f represents a group selected from the group consisting of a hydrogen atom; and an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

R ^g represents a group selected from the group consisting of a hydrogen atom; and an organic group having 1 to 30 carbon atoms which may have a substituent.

Examples of the organic group having 1 to 30 carbon atoms which may have a substituent in R ^g include an alkyl group having 1 to 20 carbon atoms which may have a substituent; At least one of -CH _2- contained in the alkyl group of 20 is -O-, -S-, -OC (= O)-, -C (= O) -O-, or -C (=). O) -Substituent group (except when two or more -O- or -S- are adjacent to each other); an alkenyl group having 2 to 20 carbon atoms which may have a substituent. An alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent; a carbon which may have a substituent. An aromatic hydrocarbon group having 6 to 30 atoms; an aromatic heterocyclic group having 2 to 30 carbon atoms which may have a substituent; -SO ₂ ^Ra ; -C (= O) -R ^b ; -CS-NH-R ^b ; can be mentioned. The meanings of R ^a and R ^b are as described above.

The preferred range and examples of the number of carbon atoms of the alkyl group having 1 to 20 carbon atoms in R ^g is the same as that of the alkyl group having 1 to 20 carbon atoms in R ^b .

Examples of the substituent which may have an alkyl group having 1 to 20 carbon atoms in R ^g, for example, fluorine atom, such as chlorine atom, a halogen atom; a cyano group; such as dimethylamino group, having 2 to 12 carbon atoms N, N-dialkylamino group; alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group, etc., having 1 to 12 carbon atoms An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group; a nitro group; an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; a triazolyl group, a pyrrolyl group, a furanyl group and a thiophenyl. Aromatic heterocyclic groups having 2 to 20 carbon atoms such as groups; cycloalkyl groups having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group; cyclopentyloxy group, cyclohexyloxy group and the like. Cycloalkyloxy group with 3 to 8 carbon atoms; cyclic ether group with 2 to 12 carbon atoms such as tetrahydrofuranyl group, tetrahydropyranyl group, dioxolanyl group and dioxanyl group; carbon atom such as phenoxy group and naphthoxy group Aryloxy group of number 6 to 14; fluoroalkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom; benzofuryl group; benzopyranyl group; benzodioxolyl group; benzodioxanyl group ; -SO ₂ R ^a ; -SR ^b ; an alkoxy group having 1 to 12 carbon atoms substituted with -SR ^b ; a hydroxyl group; and the like. The meanings of R ^a and R ^b are as described above. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The preferred range of carbon atoms and examples of alkenyl groups having 2 to 20 carbon atoms in R ^g are the same as those of alkenyl groups having 2 to 20 carbon atoms in R ^b .

Examples of the substituent which may have an alkenyl group having 2 to 20 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The alkynyl group having 2 to 20 carbon atoms in R ^g, for example, ethynyl group, propynyl group, 2-propynyl group (propargyl group), butynyl, 2-butynyl, 3-butynyl group, pentynyl group, 2- Examples thereof include a pentynyl group, a hexynyl group, a 5-hexynyl group, a heptynyl group, an octynyl group, a 2-octynyl group, a nonanyl group, a decanyl group and a 7-decanyl group.

Examples of the substituent which may have an alkynyl group having 2 to 20 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the cycloalkyl group having 3 to 12 carbon atoms in R ^g include the same example as the cycloalkyl group having 3 to 12 carbon atoms in R ^b .

Examples of the substituent which may have a cycloalkyl group having 3 to 12 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms in R ^g include the same examples as the aromatic hydrocarbon group having 6 to 30 carbon atoms in D ^{1 to} D ³ .

Examples of the substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms in R ^g can have include the same example as the substituent that the aromatic hydrocarbon group in D ^{1 to} D ³ can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic heterocyclic group having 2 to 30 carbon atoms in R ^g include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ .

Examples of the substituent which may have an aromatic heterocyclic group having 2 to 30 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an aromatic hydrocarbon group in D ¹ to D ^3. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Among those described above, as R ^g , at least one of an alkyl group having 1 to 20 carbon atoms which may have a substituent; and −CH ₂ − contained in the alkyl group having 1 to 20 carbon atoms is used. A group substituted with −O−, −S−, −OC (= O) −, −C (= O) −O−, or −C (= O) − (where −O− or − (Except when two or more S- are adjacent to each other); a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent; and 6 to 6 carbon atoms which may have a substituent. 30 aromatic hydrocarbon groups; and aromatic heterocyclic groups having 2 to 30 carbon atoms which may have a substituent; are preferable. Among them, as R ^g , at least one of an alkyl group having 1 to 20 carbon atoms which may have a substituent; and −CH ₂ − contained in the alkyl group having 1 to 20 carbon atoms is included. A group substituted with −O−, −S−, −OC (= O) −, −C (= O) −O−, or −C (= O) − (where −O− or − (Except when two or more S- are adjacent to each other); is particularly preferable.

R ^h represents an organic group having one or more aromatic rings selected from the group consisting of an aromatic hydrocarbon ring having 6 to 30 carbon atoms and an aromatic heterocycle having 2 to 30 carbon atoms.

Preferred examples of R ^h include (1) a hydrocarbon group having 6 to 40 carbon atoms and having an aromatic hydrocarbon ring having 1 or more carbon atoms and 6 to 30 carbon atoms. The hydrocarbon group having this aromatic hydrocarbon ring may be appropriately referred to as "(1) hydrocarbon group" below. (1) Specific examples of the hydrocarbon group include the following groups.

(1) The hydrocarbon group may have a substituent. (1) Examples of the substituent that the hydrocarbon group can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; an alkyl having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group. Group; Alkenyl group having 2 to 6 carbon atoms such as vinyl group and allyl group; Alkyl halide group having 1 to 6 carbon atoms such as trifluoromethyl group; 2 to 2 carbon atoms such as dimethylamino group 12 N, N-dialkylamino groups; alkoxy groups having 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group; nitro group; phenyl group, naphthyl group, etc., having 6 to 20 carbon atoms Aromatic hydrocarbon groups; -OCF ₃ ; -C (= O) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; And so on. The meanings of R ^a and R ^b are as described above. Among these, halogen atoms, cyano groups, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Another preferred example of R ^h is (2) having one or more aromatic rings selected from the group consisting of an aromatic hydrocarbon ring having 6 to 30 carbon atoms and an aromatic heterocycle having 2 to 30 carbon atoms. , Heterocyclic groups having 2 to 40 carbon atoms. The heterocyclic group having this aromatic ring may be appropriately referred to as "(2) heterocyclic group" below. (2) Specific examples of the heterocyclic group include the following groups. R each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

(2) The heterocyclic group may have a substituent. Examples of the substituent (2) that the heterocyclic group can have include the same examples as the substituent that the hydrocarbon group can have (1). The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (3) one or more groups selected from the group consisting of an aromatic hydrocarbon group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Substituted alkyl groups having 1 to 12 carbon atoms can be mentioned. Hereinafter, the substituted alkyl group may be appropriately referred to as "(3) substituted alkyl group".

(3) Examples of the "alkyl group having 1 to 12 carbon atoms" in the substituted alkyl group include a methyl group, an ethyl group, a propyl group and an isopropyl group.
(3) Examples of the "aromatic hydrocarbon group having 6 to 30 carbon atoms" in the substituted alkyl group include the same examples as the aromatic hydrocarbon group having 6 to 30 carbon atoms in D ^{1 to} D ³ . ..
(3) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(3) The substituted alkyl group may further have a substituent. Examples of the substituent that the (3) substituted alkyl group can have include the same examples as the substituent that the (1) hydrocarbon group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (4) one or more groups selected from the group consisting of an aromatic hydrocarbon group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Substituted alkenyl groups having 2 to 12 carbon atoms can be mentioned. Hereinafter, the substituted alkenyl group may be appropriately referred to as "(4) substituted alkenyl group".

(4) Examples of the "alkenyl group having 2 to 12 carbon atoms" in the substituted alkenyl group include a vinyl group and an allyl group.
(4) Examples of the "aromatic hydrocarbon group having 6 to 30 carbon atoms" in the substituted alkenyl group include the same examples as the aromatic hydrocarbon group having 6 to 30 carbon atoms in D ^{1 to} D ³ . ..
(4) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkenyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(4) The substituted alkenyl group may further have a substituent. Examples of the substituent that the (4) substituted alkenyl group can have include the same examples as the substituent that the (1) hydrocarbon group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (5) one or more groups selected from the group consisting of an aromatic hydrocarbon group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Substituted alkynyl groups having 2 to 12 carbon atoms can be mentioned. The substituted alkynyl group may be appropriately referred to as "(5) substituted alkynyl group" below.

(5) Examples of the "alkynyl group having 2 to 12 carbon atoms" in the substituted alkynyl group include an ethynyl group and a propynyl group.
(5) Examples of the "aromatic hydrocarbon group having 6 to 30 carbon atoms" in the substituted alkynyl group include the same examples as the aromatic hydrocarbon group having 6 to 30 carbon atoms in D ^{1 to} D ³ . ..
(5) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkynyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(5) The substituted alkynyl group may further have a substituent. Examples of the substituent that the (5) substituted alkynyl group can have include the same examples as the substituent that the (1) hydrocarbon group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Preferred specific examples of R ^h include the following groups.

More preferable specific examples of R ^h include the following groups.

Specific examples of R ^h being particularly preferable include the following groups.

The specific example of R ^h described above may further have a substituent. Examples of the substituent include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group; a vinyl group and an allyl group. , An alkenyl group having 2 to 6 carbon atoms; an alkyl halide group having 1 to 6 carbon atoms such as a trifluoromethyl group; an N, N-dialkylamino group having 2 to 12 carbon atoms such as a dimethylamino group. An alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, and an isopropoxy group; a nitro group; -OCF ₃ ; -C (= O) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; and the like. The meanings of R ^a and R ^b are as described above. Among these, halogen atoms, cyano groups, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

R ⁱ has one or more aromatic ring selected from the group consisting of aromatic heterocyclic aromatic hydrocarbon ring and 2 to 30 carbon atoms of 6 to 30 carbon atoms, represents an organic group.

Preferred examples of R ⁱ may have one or more aromatic hydrocarbon ring having 6 to 30 carbon atoms, and a hydrocarbon group having 6 to 40 carbon atoms.
As another preferred example of R ⁱ has one or more aromatic ring selected from the group consisting of aromatic heterocyclic aromatic hydrocarbon ring and 2 to 30 carbon atoms of 6 to 30 carbon atoms, Examples thereof include heterocyclic groups having 2 to 40 carbon atoms.

Particularly preferred specific examples of R ⁱ include the following groups. The meaning of R is as described above.

The group represented by any of the formulas (II-1) to (II-7) may have a substituent other than D ^{1 to} D ⁶ . Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, an alkyl halide group having 1 to 6 carbon atoms, and an N-alkylamino having 1 to 6 carbon atoms. Group, N, N-dialkylamino group with 2 to 12 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkylsulfinyl group with 1 to 6 carbon atoms, carboxyl group, thioalkyl group with 1 to 6 carbon atoms , N-alkylsulfamoyl group having 1 to 6 carbon atoms and N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Preferred examples of Ar in the formula (I) include groups represented by the following formulas (III-1) to (III-10). Further, the groups represented by the formulas (III-1) to (III-10) may have an alkyl group having 1 to 6 carbon atoms as a substituent. In the following formula, * represents the bond position.

Particularly preferable specific examples of the formula (III-1) and the formula (III-4) include the following groups. In the following formula, * represents the bond position.

In the formula (I), ^{Z 1} and ^{Z 2} are each independently a single _{bond, -O -, - O-CH} 2 -, - CH 2 -O -, - O-CH 2 -CH 2 -, - _{CH 2 -CH 2 -O -, -} C (= O) -O -, - O-C (= O) -, - C (= O) -S -, - S-C (= O) -, - _{^{NR 21 -C (= O) -}} , - C (= O) -NR 21 -, - CF 2 -O -, - O-CF 2 -, - CH 2 -CH 2 -, - CF 2 -CF 2 - _{, -O-CH 2 -CH 2 -O} -, - CH = CH-C (= O) -O -, - O-C (= O) -CH = CH -, - CH 2 -C (= O) _{-O -, - O-C (} = O) -CH 2 -, - CH 2 -O-C (= O) -, - C (= O) -O-CH 2 -, - CH 2 -CH 2 - _{C (= O) -O -,} - O-C (= O) -CH 2 -CH 2 -, - CH 2 -CH 2 -O-C (= O) -, - C (= O) -O- _{CH 2 -CH 2 -, - CH} = CH -, - N = CH -, - CH = N -, - N = C (CH 3) -, - C (CH 3) = N -, - N = N- , And −C≡C−, representing any of the groups selected from the group. R ²¹ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), A ¹ , A ² , B ¹ and B ² independently have a cyclic aliphatic group which may have a substituent and an aromatic which may have a substituent. Represents a group selected from the group consisting of family groups. The number of carbon atoms of the group represented by A ¹ , A ² , B ¹ and B ² (including the number of carbon atoms of the substituent) is usually 3 to 100 independently of each other. Among them, A ¹ , A ² , B ¹ and B ² each independently have a cyclic aliphatic group having 5 to 20 carbon atoms or a substituent which may have a substituent. Aromatic groups having 2 to 20 carbon atoms are preferable.

Examples of the cyclic aliphatic group in A ¹ , A ² , B ¹ and B ² include cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cycloheptane-1,4-diyl group, and the like. Cycloalkanediyl group having 5 to 20 carbon atoms such as cyclooctane-1,5-diyl group; carbon atom such as decahydronaphthalene-1,5-diyl group and decahydronaphthalene-2,6-diyl group The number 5 to 20 bicycloalkandyl groups; etc. may be mentioned. Of these, a cycloalkandyl group having 5 to 20 carbon atoms which may be substituted is preferable, a cyclohexanediyl group is more preferable, and a cyclohexane-1,4-diyl group is particularly preferable. The cyclic aliphatic group may be a trans form, a cis form, or a mixture of a cis form and a trans form. Among them, the transformer body is more preferable.

Examples of the substituent that the cyclic aliphatic group in A ¹ , A ² , B ¹ and B ² can have include a halogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples include a nitro group and a cyano group. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic group in A ¹ , A ² , B ¹ and B ² include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,4-naphthylene group, 1, Aromatic hydrocarbon groups with 6 to 20 carbon atoms such as 5-naphthylene group, 2,6-naphthylene group, 4,4'-biphenylene group; furan-2,5-diyl group, thiophene-2,5- Examples thereof include aromatic heterocyclic groups having 2 to 20 carbon atoms such as a diyl group, a pyridine-2,5-diyl group and a pyrazine-2,5-diyl group. Among them, an aromatic hydrocarbon group having 6 to 20 carbon atoms is preferable, a phenylene group is more preferable, and a 1,4-phenylene group is particularly preferable.

A ^1, as the ^A 2, ^{B 1} and substituents aromatic group may have at ^{B 2,} for ^{example, A 1, A 2, B} 1 and the same as the substituent which may have a cyclic aliphatic group in ^{B 2} For example. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the formula (I), Y ^{1 to} Y ⁴ are independently single-bonded, -O-, -C (= O)-, -C (= O) -O-, -OC (= O). ^{) -, - NR 22 -C (} = O) -, - C (= O) -NR 22 -, - O-C (= O) -O -, - NR 22 -C (= O) -O-, It represents any one selected from the group consisting of −O—C (= O) −NR ²² − and −NR ²² −C (= O) −NR ²³ −. R ²² and R ²³ independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), G ¹ and G ² are independent aliphatic hydrocarbon groups having 1 to 20 carbon atoms; and methylene groups contained in the aliphatic hydrocarbon groups having 3 to 20 carbon atoms. Represents an organic group selected from the group consisting of a group in which one or more of (-CH _2- ) is substituted with -O- or -C (= O)-. The hydrogen atom contained in the organic group of G ¹ and G ² may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom. However, the methylene groups (-CH _2- ) at both ends of G ¹ and G ² are not replaced with -O- or -C (= O)-.

Specific examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms in G ¹ and G ² include an alkylene group having 1 to 20 carbon atoms.

Specific examples of the aliphatic hydrocarbon group having 3 to 20 carbon atoms in G ¹ and G ² include an alkylene group having 3 to 20 carbon atoms.

In formula (I), P ¹ and P ² each independently represent a polymerizable group. Examples of the polymerizable group in P ¹ and P ² include acryloyloxy group, methacryloyloxy group and the like represented by CH ₂ = CR ^31- C (= O) -O-; vinyl group; vinyl ether group; p-Stilben group; acryloyl group; methacryloyl group; carboxyl group; methylcarbonyl group; hydroxyl group; amide group; alkylamino group having 1 to 4 carbon atoms; amino group; epoxy group; oxetanyl group; aldehyde group; isocyanate group; thio Isocyanate group; and the like. R ³¹ represents a hydrogen atom, a methyl group, or a chlorine atom. Among them, the group represented by CH ₂ = CR ^31- C (= O) -O- is preferable, CH ₂ = CH-C (= O) -O- (acryloyloxy group), CH ₂ = C (CH _3). ) -C (= O) -O- (methacryloyloxy group) is more preferable, and acryloyloxy group is particularly preferable.

In formula (I), p and q independently represent 0 or 1, respectively.

In formula (I), t represents 1 or 2.

The inversely dispersed liquid crystal compound represented by the formula (I) can be produced, for example, by reacting a hydrazine compound with a carbonyl compound described in International Publication No. 2012/147904.

Specific examples of the liquid crystal compound represented by the formula (I) include a compound represented by the following formula.

The liquid crystal composition may further contain any component in combination with the inversely dispersed liquid crystal compound, if necessary. As the arbitrary component, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

For example, in order to promote the polymerization of the inversely dispersed liquid crystal compound, the liquid crystal composition may contain a polymerization initiator as an arbitrary component. As the polymerization initiator, either a thermal polymerization initiator or a photopolymerization initiator may be used. Above all, from the viewpoint of remarkably obtaining the desired effect of the present invention, it is preferable to use a photopolymerization initiator.

The type of the polymerization initiator can be selected according to the type of the polymerizable compound contained in the liquid crystal composition. For example, if the polymerizable compound is radically polymerizable, a radical polymerization initiator can be used. If the polymerizable compound is anionically polymerizable, an anionic polymerization initiator may be used. Further, if the polymerizable compound is cationically polymerizable, a cationic polymerization initiator can be used. One type of polymerization initiator may be used alone, or two or more types may be used in combination at any ratio.

The amount of the polymerization initiator is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, preferably 30 parts by weight or less, more preferably more preferably, with respect to 100 parts by weight of the reverse dispersion liquid crystal compound. It is 10 parts by weight or less. When the amount of the polymerization initiator is within the above range, the polymerization can proceed efficiently.

For example, the liquid crystal composition may contain a surfactant as an arbitrary component. In particular, from the viewpoint of improving the coatability of the liquid crystal composition and stably obtaining a liquid crystal cured film having excellent orientation, as the surfactant, a surfactant containing a fluorine atom in the molecule is used. preferable. In the following description, a surfactant containing a fluorine atom in the molecule may be appropriately referred to as a "fluorine-based surfactant".

The surfactant is preferably a nonionic surfactant. When the surfactant is a nonionic surfactant containing no ionic group, the surface condition and orientation of the liquid crystal cured film can be particularly improved.

Examples of the surfactant include AGC Seimi Chemical's Surflon series (S242, S386, S420, etc.) and DIC's Megafuck series (F251, F554, F556, F562, RS-75, RS-76-). E, etc.), the footgent series manufactured by Neos (FTX601AD, FTX602A, FTX601ADH2, FTX650A, 209F, etc.) and the like. Further, one type of surfactant may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The amount of the surfactant is preferably 0.005 parts by weight or more, more preferably 0.010 parts by weight or more, and preferably 1.00 parts by weight or less, based on 100 parts by weight of the reverse dispersion liquid crystal compound. It is preferably 0.50 parts by weight or less. When the amount of the surfactant is in the above range, the surface condition of the liquid crystal cured film can be made particularly good, and the occurrence of orientation defects of the liquid crystal cured film can be effectively suppressed.

For example, the liquid crystal composition may contain a solvent as an arbitrary component. As the solvent, a solvent capable of dissolving the inversely dispersed liquid crystal compound is preferable. As such a solvent, an organic solvent is usually used. Examples of organic solvents include ketone solvents such as cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone and methyl isobutyl ketone; acetate solvents such as butyl acetate and amyl acetate; halogenated hydrocarbon solvents such as chloroform, dichloromethane and dichloroethane; 1 , 4-Dioxane, cyclopentylmethyl ether, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,2-dimethoxyethane and other ether solvents; and aromatic hydrocarbon solvents such as toluene, xylene and mesitylene; Further, one type of solvent may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The boiling point of the solvent is preferably 60 ° C. to 250 ° C., more preferably 60 ° C. to 150 ° C. from the viewpoint of excellent handleability.

The amount of the solvent is preferably 200 parts by weight or more, more preferably 250 parts by weight or more, particularly preferably 300 parts by weight or more, and preferably 650 parts by weight or less, based on 100 parts by weight of the inversely dispersed liquid crystal compound. It is preferably 600 parts by weight or less, and particularly preferably 500 parts by weight or less. When the amount of the solvent is at least the lower limit of the above range, the generation of foreign matter can be suppressed. Further, when the amount of the solvent is not more than the upper limit of the above range, the drying load can be reduced.

For example, the liquid crystal composition may contain, as an arbitrary component, a tilting action component capable of exerting an action of increasing the substantially maximum tilt angle of the molecule of the inversely dispersed liquid crystal compound. When the tilting action component is used, the tilting of the molecules of the back-dispersed liquid crystal compound can be promoted, and a liquid crystal cured film having a large tilt angle of the molecules of the back-dispersed liquid crystal compound can be easily obtained. As such a tilting action component, for example, the components described in JP-A-2018-163218, JP-A-2018-162379, International Publication No. 2018/173778 and the like can be used.

Any other components that the liquid crystal composition may contain include, for example, metals; metal complexes; metal oxides such as titanium oxide; colorants such as dyes and pigments; light emitting materials such as fluorescent materials and phosphorescent materials; leveling agents; Tixo agents; gelling agents; polysaccharides; antioxidants; UV absorbers; infrared absorbers; antioxidants; ion exchange resins; etc. The amount of these components may be 0.1 parts by weight to 20 parts by weight, respectively, with respect to 100 parts by weight of the total of the inversely dispersed liquid crystal compounds.

In the step of forming the layer of the liquid crystal composition, the liquid crystal composition is usually prepared in a fluid state. Therefore, usually, the liquid crystal composition is applied to the rubbing-treated surface of the base material to form a layer of the liquid crystal composition. Examples of the method for coating the liquid crystal composition include curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, print coating method, and gravure. Examples include a coating method, a die coating method, a gap coating method, and a dipping method.

[8. Orientation processing]
After forming a layer of the liquid crystal composition on the rubbing-treated surface of the base material, before curing the layer of the liquid crystal composition, an orientation treatment for orienting the reverse-dispersed liquid crystal compound contained in the layer of the liquid crystal composition is performed. May be good. By performing the alignment treatment, the inversely dispersed liquid crystal compound can be smoothly oriented in the direction corresponding to the orientation regulating force of the rubbing treatment surface of the base material.

The orientation treatment is usually carried out by adjusting the temperature of the layer of the liquid crystal composition to a predetermined orientation temperature. The orientation temperature can be a temperature equal to or higher than the liquid crystal formation temperature of the liquid crystal composition. At this time, the orientation temperature is preferably a temperature lower than the glass transition temperature of the resin contained in the base material. As a result, it is possible to suppress the occurrence of distortion of the base material due to the orientation treatment.

Normally, in the in-plane direction, the inversely dispersed liquid crystal compound is oriented in a direction corresponding to the orientation regulating force on the surface of the base material. Further, depending on the composition of the liquid crystal composition, the state of the rubbing treatment surface of the base material, the treatment conditions of the orientation treatment, and the like, in the thickness direction, a part or all of the inversely dispersed liquid crystal compound has a layer plane. It may be oriented so as to be inclined. In this case, the orientation treatment may be performed under appropriate conditions in order to increase the inclination angle of the molecules of the inversely dispersed liquid crystal compound with respect to the layer plane. Examples of the method for increasing the inclination angle of the molecule of the inversely dispersed liquid crystal compound with respect to the layer plane include Patent No. 5363022, International Publication No. 2018/173778, Japanese Patent Application Laid-Open No. 2018-163218, and Japanese Patent Application Laid-Open No. 2018-162379. The method described in Gazette, WO 2018/173773 can be used.

The time for holding the temperature of the layer of the liquid crystal composition at a predetermined orientation temperature during the alignment treatment can be arbitrarily set within a range in which a desired liquid crystal cured film can be obtained, and may be, for example, 30 seconds to 5 minutes.

[9. Hardening process]
The method for producing a liquid crystal cured film according to the present embodiment includes a step of forming a layer of the liquid crystal composition on the rubbing-treated surface of the base material and then curing the layer of the liquid crystal composition. Curing of the liquid crystal composition in this step is usually achieved by polymerization of the polymerizable compound contained in the liquid crystal composition. Therefore, when the reverse-dispersed liquid crystal compound has polymerizability, the layer of the liquid crystal composition is cured by polymerizing a part or all of the reverse-dispersed liquid crystal compound. The polymerization usually proceeds while maintaining the molecular orientation of the liquid crystal compound. Therefore, by the above-mentioned polymerization, the orientation state of the liquid crystal compound contained in the liquid crystal composition before the polymerization is fixed.

As the polymerization method, a method suitable for the properties of the components contained in the liquid crystal composition can be selected. Examples of the polymerization method include a method of irradiating with active energy rays and a thermal polymerization method. Above all, the method of irradiating with active energy rays is preferable because heating is not required and the polymerization reaction can proceed at room temperature. Here, the activated energy rays to be irradiated may include light such as visible light, ultraviolet rays, and infrared rays, and arbitrary energy rays such as electron beams.

Of these, a method of irradiating light such as ultraviolet rays is preferable because the operation is simple. The temperature at the time of ultraviolet irradiation is preferably not less than the glass transition temperature of the base material from the viewpoint of not adversely affecting the base material, preferably 150 ° C. or less, more preferably 100 ° C. or less, and particularly preferably 80 ° C. It is as follows. The lower limit of the temperature at the time of ultraviolet irradiation is preferably 15 ° C. or higher, and more preferably 20 ° C. or higher. The irradiation intensity of ultraviolet rays is preferably 0.1 mW / cm ² or more, more preferably 0.5 mW / cm ² or more, preferably 10000 mW / cm ² or less, more preferably 5000 mW / cm ² or less. The dose of ultraviolet rays is preferably 0.1 mJ / cm ² or more, more preferably 0.5 mJ / cm ² or more, preferably 10000 mJ / cm ² or less, more preferably 5000 mJ / cm ² or less.

By curing the layer of the liquid crystal composition as described above, a liquid crystal cured film formed of the cured product of the liquid crystal composition can be obtained. The liquid crystal cured film thus obtained has suppressed bright spots and is excellent in orientation. In addition, this liquid crystal cured film is usually excellent in planar shape and orientation uniformity.

[10. Arbitrary process]
The method for producing a liquid crystal cured film according to the present embodiment may further include an arbitrary step in combination with the above-mentioned steps.
For example, in the above-described embodiment, the liquid crystal cured film is usually obtained on the rubbing surface of the base material. Therefore, the method for producing the liquid crystal cured film is an arbitrary step of peeling the liquid crystal cured film from the rubbing surface. May include.

Further, the method for producing the liquid crystal cured film may include, for example, a step of further forming an arbitrary layer on the liquid crystal cured film.

Further, the method for producing a liquid crystal cured film may include, for example, a step of transferring the liquid crystal cured film formed on the substrate to an arbitrary film layer. Therefore, for example, the method for producing a liquid crystal cured film may include a step of laminating the liquid crystal cured film formed on the base material and an arbitrary film layer, and then peeling off the base material as necessary. .. At this time, an appropriate adhesive or adhesive may be used for bonding.

Further, the method for producing the liquid crystal cured film may include, for example, a step of drying the layer of the liquid crystal composition before curing the layer of the liquid crystal composition. Such drying can be achieved by a drying method such as natural drying, heat drying, vacuum drying, and vacuum heating drying. By such drying, the solvent can be removed from the layer of the liquid crystal composition.

When the above-mentioned production method is carried out using a strip-shaped base material, a long liquid crystal cured film can be obtained. Such a long liquid crystal cured film can be continuously produced and is excellent in productivity. Further, since the long liquid crystal cured film can be bonded to another film by roll-to-roll, the productivity is also excellent in this respect as well. Usually, a long liquid crystal cured film is wound and stored and transported in a roll state.

[11. Liquid crystal cured film]
Since the liquid crystal cured film produced by the above-mentioned production method is formed of a cured product obtained by curing a layer of a liquid crystal composition containing a back-dispersed liquid crystal compound, it contains molecules of the back-dispersed liquid crystal compound. Curing of the liquid crystal composition is usually achieved by the polymerization of the polymerizable compound contained in the liquid crystal product. Therefore, the liquid crystal cured film usually contains a polymer of a part or all of the components contained in the liquid crystal composition. Therefore, when the back-dispersed liquid crystal compound is polymerizable, the liquid crystal cured film may contain a polymer of the back-dispersed liquid crystal compound. Normally, the liquid crystal property of the reverse-dispersed liquid crystal compound is lost by polymerization, but in the present application, the reverse-dispersed liquid crystal compound thus polymerized is also included in the term "reverse-dispersed liquid crystal compound contained in the liquid crystal cured film".

Usually, in the liquid crystal cured film, the orientation state of the inversely dispersed liquid crystal compound can be fixed. The term "reverse-dispersed liquid crystal compound having a fixed orientation state" includes a polymer of the above-mentioned reverse-dispersed liquid crystal compound. The liquid crystal cured film may contain molecules of the inversely dispersed liquid crystal compound whose orientation state is not fixed by combining with the molecules of the inversely dispersed liquid crystal compound whose orientation state is fixed, but the reverse liquid crystal curing film contains the reverse. It is preferable that all the molecules of the dispersed liquid crystal compound have a fixed orientation.

In the liquid crystal cured film produced by the above-mentioned production method, the generation of bright spots can be suppressed. Specifically, the number of bright spots observed can be reduced when the bright spot evaluation test is performed. Here, in the bright spot evaluation test, the polarizer and the analyzer are stacked on the light table so as to form a cross Nicol. Cross Nicol means that the absorption axis of the polarizer and the absorption axis of the analyzer are perpendicular to each other when viewed from the thickness direction. Then, a liquid crystal curing film is placed between the polarizer and the analyzer, and the slow axis of the liquid crystal curing film and the absorption axis of the polarizer are adjusted so as to be parallel when viewed from the thickness direction. In this state, the light table is turned on and the light transmitted through the polarizer, the film piece and the analyzer is observed. When this bright spot evaluation test is performed, the number of bright spots of the liquid crystal cured film can be preferably less than 5 pieces / 256 cm ² and more preferably less than 1 piece / 256 cm ² and particularly preferably the bright spots. It can be eliminated.

The liquid crystal cured film produced by the above-mentioned production method can have good orientation. That is, when the liquid crystal compound contained in the liquid crystal cured film is usually oriented, the disorder in the orientation direction of the liquid crystal compound contained in the liquid crystal cured film can be reduced, so that the occurrence of orientation defects can be suppressed. Specifically, when the orientation evaluation test is performed, the leakage light can be reduced. Here, in the orientation evaluation test, the liquid crystal cured film is observed under a cross Nicol using a polarizing microscope. The above observation is performed by adjusting the position of the liquid crystal cured film to (i) the quenching position and (ii) the position where the slow axis of the liquid crystal cured film is shifted by several degrees from the quenching position. When this orientation evaluation test is performed, the observed leakage light can be reduced.

Usually, in the liquid crystal cured film produced by the above-mentioned production method, the orientation uniformity of the liquid crystal cured film can be improved. That is, usually, the orientation can be made uniform in the in-plane direction of the liquid crystal cured film. Therefore, for example, a long liquid crystal cured film can have the same degree of orientation at any position in the width direction.

Generally, the liquid crystal cured film produced by the above-mentioned production method can have an excellent surface shape. That is, the surface of the liquid crystal cured film can usually be made uniform. Specifically, unevenness can be reduced when a planar evaluation test is performed. Here, in the planar evaluation test, the polarizer and the analyzer are stacked on the light table so as to form a cross Nicol. Then, a liquid crystal curing film is placed between the polarizer and the analyzer, and the slow axis of the liquid crystal curing film and the absorption axis of the polarizer are adjusted so as to form an angle of 45 ° when viewed from the thickness direction. In this state, the light table is turned on and the light transmitted through the polarizer, the film piece and the analyzer is observed. When this planar evaluation test is performed, the observed unevenness can be reduced.

Since the liquid crystal cured film contains an oriented reverse dispersion liquid crystal compound, it is usually possible to develop a reverse wavelength dispersible retardation. Specifically, the in-plane retardations Re (450) and Re (550) of the liquid crystal cured film at the measurement wavelengths of 450 nm and 550 nm can satisfy the following formula (N2). As described above, the liquid crystal cured film having the reverse wavelength dispersibility in-plane retardation can uniformly exhibit its function in a wide wavelength band in optical applications such as a 1/4 wave plate or a 1/2 wave plate.
Re (450) / Re (550) <1.00 (N2)

In the in-plane direction of the liquid crystal cured film, the orientation direction of the molecules of the inversely dispersed liquid crystal compound is usually uniform. Therefore, the liquid crystal cured film usually has an in-plane slow-phase axis parallel to the orientation direction of the molecules of the inversely dispersed liquid crystal compound when the liquid crystal cured film is viewed from the thickness direction. Since the inversely dispersed liquid crystal compound is oriented in a certain orientation direction in the in-plane direction in this way, the liquid crystal cured film usually has an in-plane retardation of a predetermined size.

The specific range of in-plane retardation of the liquid crystal curable film can be arbitrarily set according to the use of the liquid crystal curable film. By appropriately setting the range of the in-plane retardation, the liquid crystal cured film can exhibit the optical function as an optical film such as a 1/4 wave plate and a 1/2 wave plate.
For example, when it is desired to make the liquid crystal cured film function as a 1/4 wave plate, the in-plane retardation of the liquid crystal cured film is preferably 100 nm or more, more preferably 110 nm or more, and particularly preferably 120 nm or more at a measurement wavelength of 590 nm. It is preferably 180 nm or less, more preferably 170 nm or less, and particularly preferably 160 nm or less.
Further, for example, when the liquid crystal cured film is desired to function as a 1/2 wavelength plate, the retardation of the liquid crystal cured film is preferably 245 nm or more, more preferably 265 nm or more, and particularly preferably 270 nm or more at a measurement wavelength of 590 nm. It is preferably 320 nm or less, more preferably 300 nm or less, and particularly preferably 295 nm or less.

In the thickness direction of the liquid crystal cured film, the orientation direction of the molecules of the inversely dispersed liquid crystal compound is arbitrary. For example, in the thickness direction of the liquid crystal cured film, the orientation direction of the molecules of the inversely dispersed liquid crystal compound may be parallel to or non-parallel to the surface of the liquid crystal cured film. Further, in the thickness direction of the liquid crystal cured film, the orientation direction of the molecules of the inversely dispersed liquid crystal compound may be uniform or non-uniform. To give a specific example, the molecules of the inversely dispersed liquid crystal compound may be oriented in one direction parallel to the plane of the liquid crystal cured film (homogeneous orientation). Further, the molecules of the inversely dispersed liquid crystal compound may be oriented in a direction perpendicular to the surface of the liquid crystal cured film (vertical orientation). Further, the molecules of the inversely dispersed liquid crystal compound may be oriented in a certain direction that is neither parallel nor perpendicular to the plane of the liquid crystal cured film (inclined orientation). Further, the molecules of the inversely dispersed liquid crystal compound are smaller as the inclination angle formed by the molecules of the inverse dispersed liquid crystal compound with respect to the layer plane of the liquid crystal cured film is closer to one side of the liquid crystal cured film, and is farther from the one side. It may be oriented in a mode larger than that (hybrid orientation).

Above all, in the orientation state of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film, at least some of the molecules are inclined with respect to the layer plane of the liquid crystal cured film as in the above-mentioned inclined orientation and hybrid orientation. Is preferable. According to the method for producing a liquid crystal cured film described above, when a liquid crystal cured film containing molecules of a reversely dispersed liquid crystal compound oriented in a direction inclined with respect to a layer plane is produced, the molecules of the inversely dispersed liquid crystal compound are produced. The tilt angle can be increased. In particular, when the method for producing the liquid crystal cured film includes performing a surface modification treatment such as a corona treatment, the inclination angle can be effectively increased. Therefore, from the viewpoint of utilizing the advantage of being able to increase the inclination angle in this way, the above-mentioned production method produces a liquid crystal cured film containing molecules of a reverse-dispersed liquid crystal compound oriented in a direction inclined with respect to the layer plane. It is preferable to do so.

The fact that at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film are oriented in an inclined direction with respect to the layer plane of the liquid crystal cured film means that the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound is Can be confirmed by. Normally, when the actual maximum inclination angle of the molecules of the reverse-dispersed liquid crystal compound contained in the liquid crystal cured film is 5 ° or more and 85 ° or less, at least a part of the molecules of the reverse-dispersed liquid crystal compound contained in the liquid crystal cured film is present. It is oriented in a direction inclined with respect to the layer plane of the liquid crystal cured film.

The "substantially maximum tilt angle" of the molecules of the liquid crystal compound contained in a certain layer is that the tilt angle of the molecule on one surface of the layer is 0 ° and the tilt angle of the molecule is a constant ratio in the thickness direction. It is the maximum value of the inclination angle of the molecule of the liquid crystal compound when it is assumed that it is changing. In the liquid crystal curable film, the inclination angle of the molecules of the liquid crystal compound may be smaller as it is closer to one side of the liquid crystal curable film and larger as it is farther from the one side in the thickness direction. The actual maximum tilt angle is calculated on the assumption that the rate of change in the tilt angle in the thickness direction (that is, the rate of change that decreases as it is closer to one side and increases as it is farther from one side) is constant. Represents the maximum value of the tilt angle. Usually, in the liquid crystal cured film produced by the above-mentioned production method, the substantially maximum inclination angle is such that the inclination angle of the molecule on the surface on the substrate side is 0 ° and the inclination angle of the molecule is constant in the thickness direction. It represents the maximum value of the inclination angle of the molecule of the inversely dispersed liquid crystal compound, assuming that it changes with the ratio.

As described above, the substantially maximum tilt angle can be an index indicating the magnitude of the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film. Therefore, it can be confirmed that at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film is oriented in the direction inclined with respect to the layer plane of the liquid crystal cured film by the substantially maximum inclination angle. Generally, the larger the substantially maximum tilt angle of a liquid crystal cured film, the larger the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the cured liquid crystal film as a whole. By adjusting the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film, it is possible to adjust the birefringence in the thickness direction of the liquid crystal cured film.

The range of the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film can be appropriately set according to the use of the liquid crystal cured film. The substantially maximum inclination angle can be usually set in the range of 5 ° to 85 °, preferably 30 ° or more, and more preferably 40 ° or more. The substantially maximum tilt angle can be measured by the method described in the examples.

The thickness of the liquid crystal cured film can be appropriately set so that the characteristics such as retardation can be in a desired range. Specifically, the thickness of the liquid crystal cured film is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 10.0 μm or less, more preferably 7.0 μm or less, and particularly preferably 5.0 μm. It is as follows.

The liquid crystal cured film preferably has excellent transparency. Specifically, the total light transmittance of the liquid crystal cured film is preferably 75% or more, more preferably 80% or more, and particularly preferably 84% or more. The haze of the liquid crystal cured film is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet / visible spectrometer. Haze can also be measured using a haze meter.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples described below, and may be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "%" and "part" representing the amount are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and pressure conditions unless otherwise specified.

[Evaluation and measurement method]
<Evaluation method of surface condition of liquid crystal cured film>
The sample film was cut into a 16 cm square size to obtain a film piece. A polarizer and an analyzer were placed on a light table in an overlapping manner, and the film piece was placed between the polarizer and the analyzer. The angle formed by the slow axis of the liquid crystal cured film of the film piece and the absorption axis of the polarizer when viewed from the thickness direction was adjusted to 45 °. Further, the absorption axis of the polarizer and the absorption axis of the analyzer were adjusted so as to form a cross Nicol perpendicular to the thickness direction. In this state, the light table was turned on and visually observed.

From the results of the above observations, the surface shape was evaluated according to the following criteria according to the appearance uniformity (uniformity of phase difference).
S: The entire surface is almost uniform, and no unevenness or defects are observed.
A: The entire surface is almost uniform, but slight unevenness is observed.
B: Unevenness is clearly observed.
C: Strong unevenness is seen on the entire surface.

<Evaluation of bright spots on liquid crystal cured film>
The sample film was cut into a 16 cm square size to obtain a film piece. A polarizer and an analyzer were placed on a variable-luminance light table having a brightness of 20000 cd or more, and the film piece was placed between the polarizer and the analyzer. The angle formed by the slow axis of the liquid crystal cured film of the film piece and the absorption axis of the polarizer when viewed from the thickness direction was adjusted to approximately 0 °. Further, the absorption axis of the polarizer and the absorption axis of the analyzer were adjusted so as to form a cross Nicol perpendicular to the thickness direction. In this state, the light table was turned on and visually observed.

From the results of the above observations, the number of points at which the light transmitted through the polarizer, the film piece and the analyzer was observed was counted as a "bright spot" and evaluated according to the following criteria.
A: No bright spots are observed.
B: The number of bright spots is 1 or more and less than 5.
C: The number of bright spots is 5 or more and less than 10.
D: The number of bright spots is 10 or more.

<Evaluation of orientation of liquid crystal cured film>
The liquid crystal cured film contained in the sample film was attached to a glass plate with an adhesive, and the base material was peeled off. As a result, a sample piece including a glass plate, an adhesive layer and a liquid crystal curing film was obtained. The glass plate and the pressure-sensitive adhesive layer are optically isotropic and have substantially no slow axis and retardation.

The liquid crystal cured film of the sample piece was observed at the center portion (CT) in the width direction of the liquid crystal cured film under a cross Nicol using a polarizing microscope. The above observation was performed by adjusting the position of the liquid crystal cured film to (i) the quenching position and (ii) the position where the slow axis of the liquid crystal cured film was shifted by several degrees from the quenching position. In addition, the observation was performed with an objective of 5 times and 50 times, respectively. In the above observation, the degree of orientation defects and the state of leaked light were visually observed, and based on the results, evaluation was made according to the following criteria.
A: No orientation defects are seen, and almost no light leakage at the quenching position is felt.
B: A slight orientation defect is observed, and there is a slight leakage of light at the quenching position.
C: Orientation defects are clearly seen, and light leaks at the quenching position.

<Evaluation of uniformity of orientation of liquid crystal cured film in the width direction>
By the method described in <Evaluation of orientation of liquid crystal cured film>, the degree of orientation defect of the liquid crystal cured film and the state of leaked light can be observed not only at the center portion (CT) in the width direction of the liquid crystal cured film but also at the width. This was also done at one end (operation side; OS) and the other end (drive side; DS) of the direction. From the results of the measurements at these three locations, the uniformity of orientation in the width direction was evaluated according to the following criteria.
Good: The degree of orientation defect and the state of leaked light are the same at the central portion (CT), one end (OS) and the other end (DS) in the width direction.
Defectiveness: The degree of orientation defect and the state of leaked light differ depending on the central portion (CT), one end (OS) and the other end (DS) in the width direction.

<Measurement of tilt angle of molecules of liquid crystal compound contained in liquid crystal cured film>
The retardation of the liquid crystal cured film of the sample piece prepared in the above <evaluation of orientation of the liquid crystal cured film> was measured at a wavelength of 550 nm using a phase difference meter (“AxoScan” manufactured by Axometrics). This measurement was performed a plurality of times by changing the angle formed by the measurement direction of the measurement and the slow axis of the liquid crystal cured film. At this time, in each measurement, the measurement direction was set perpendicular to the phase advance axis of the liquid crystal cured film. By analyzing the measurement results of these retardations with the multi-layer analysis software (analysis software "Multi-Layer Analysis" manufactured by Compound) attached to the above phase difference meter; the analysis condition is 20 layers divided into layers). , The substantially maximum inclination angle Θ of the molecule of the liquid crystal compound contained in the liquid crystal cured film was calculated.

<Measurement of in-plane retardation of liquid crystal composition film>
The in-plane retardation of the liquid crystal cured film of the sample piece prepared in the above <Evaluation of orientation of liquid crystal cured film> was measured at wavelengths of 450 nm, 550 nm, and 650 nm using a phase difference meter (“AxoScan” manufactured by Axometrics). did.

[Production Example 1: Preparation of liquid crystal composition (L1)]
100.0 parts of the reverse dispersion liquid crystal compound (E1) represented by the following formula (E1), 0.30 part of the surfactant ("Megafuck F562" manufactured by DIC Corporation), and 3 parts of the polymerization initiator ("IRGACURE379" manufactured by BASF Corporation). A liquid liquid crystal composition by mixing 0.0 part, 188.0 parts of cyclopentanone (manufactured by Nippon Zeon) as a solvent, and 282.0 parts of 1,3-dioxolane (manufactured by Toho Kagaku Co., Ltd.) as a solvent. The product (L1) was prepared.

[Production Example 2: Preparation of liquid crystal composition (L2)]
100.0 parts of the inverse dispersion liquid crystal compound (E1) represented by the formula (E1), 0.15 parts of a surfactant (“Surflon S420” manufactured by AGC Seimi Chemical Co., Ltd.), a polymerization initiator (“IRGACURE379” manufactured by BASF). Liquid liquid crystal by mixing 3.0 parts, 188.0 parts of cyclopentanone (manufactured by Nippon Zeon) as a solvent, and 282.0 parts of 1,3-dioxolane (manufactured by Toho Kagaku Co., Ltd.) as a solvent. The composition (L2) was prepared.

[Example 1-1]
(Preparation of strip-shaped base material)
A long resin film (“ZEONOR” manufactured by ZEON Corporation, thickness 55 μm, SP value = 8.5) formed of norbornene-based resin is cut to a width of 660 mm to obtain a long strip-shaped base material. It was.

(Rubbing process)
The strip-shaped base material was subjected to a rubbing treatment by the same operation as that described in Example A1 of International Publication No. 2016/152685, except that the swing angle of the rubbing roll was 90 °.
Specifically, using the rubbing device A100 schematically shown in FIGS. 1 to 5, the strip-shaped base material obtained in the above step (preparation of the strip-shaped base material) was subjected to a rubbing treatment. At this time, the diameters of the two cylindrical free rolls (grip rolls) A110 and A150 were set to 80 mm. The diameter of the cylindrical rubbing roll A130 was 120 mm. The shaft A11X of the free roll A110 and the shaft A13X of the rubbing roll A130 are installed in the horizontal direction, and the transport path of the strip-shaped base material A13 from the free roll A110 to the rubbing roll A130 is also in the horizontal direction. Adjusted the relationship. The swing angle of the rubbing roll A130 was 90 °, and the holding angle was 60 °. The transport path from when the strip-shaped base material leaves the free roll A110 to when it comes into contact with the free roll A150 is set to about 1000 mm, and the position and angle of the free roll are adjusted from that state, and the strip-shaped base material A13 carried into the rubbing roll A130. The carry-in direction and the carry-out direction of the band-shaped base material A14 carried out from the rubbing roll A130 are the same in the width direction of the band-shaped base material (based on the carry-in or carry-out direction at the center of the band-shaped base material width direction, the reference direction and others. The angle between the carry-in or carry-out direction is within 0.5 °). The maximum value εmax of the surplus amount of the strip-shaped base material was set to 0.05% or less. The line speed for transporting the strip-shaped base material (A11 to A16) was 4 m / min, and the tension was 150 N / m. The rubbing roll A130 was rotated in the reverse direction at 1000 rpm (rotation in the direction indicated by the arrow AR2 in the figure).

(Washing process)
The strip-shaped base material subjected to the rubbing treatment was further continuously conveyed in the longitudinal direction, and immersed in a liquid tank containing ultrapure water (SP value = 23.4) as a cleaning liquid for 30 seconds. As a result, the rubbing-treated surface of the strip-shaped base material was cleaned with the cleaning liquid. Then, the cleaning liquid was removed from the rubbing surface by blowing air with an air knife.

(Formation of liquid crystal cured film)
The liquid crystal composition (L1) prepared in Production Example 1 was applied to the rubbing-treated surface of the strip-shaped base material using a die coater to form a layer of the liquid crystal composition. Next, the layer of the liquid crystal composition was subjected to an orientation treatment of heating at 110 ° C. for 4 minutes to orient the liquid crystal compound contained in the layer. Then, under a nitrogen atmosphere, the layer of the liquid crystal composition was irradiated with ultraviolet rays of 400 mJ / cm ² to be cured, and a liquid crystal cured film having a dry film thickness of 2.2 μm was formed on the rubbing-treated surface of the strip-shaped substrate. As a result, a sample film including a band-shaped base material and a liquid crystal curing film formed on the band-shaped base material was obtained. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above. The in-plane retardation of the liquid crystal cured film measured by the method described above was 112 nm / 141 nm / 146 nm at the measurement wavelengths of 450 nm / 550 nm / 650 nm, respectively.

[Examples 1-2 to 1-5]
As shown in Table 1, the types of cleaning liquids are ethanol (SP value = 12.7; Example 1-2), 1,3-dioxolane (SP value = 10.2; Example 1-3), acetone ( The band-shaped group was subjected to the same operation as in Example 1-1 except that the SP value was changed to 10.0; Example 1-4) or cyclopentanone (SP value = 10.0; Example 1-5). A sample film including the material and the liquid crystal curing film was produced. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Comparative Example 1-1]
A sample film including the strip-shaped substrate and the liquid crystal curing film was produced by the same operation as in Example 1-1 except that the rubbing-treated surface of the strip-shaped substrate was not cleaned with the cleaning liquid. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Results of Examples 1-1 to 1-5 and Comparative Example 1-1]
The results of Examples 1-1 to 1-5 and Comparative Example 1-1 are shown in Table 1 below.

[Examination of Examples 1-1 to 1-5 and Comparative Example 1-1]
As shown in Table 1, the bright spots and orientation are improved in Examples 1-1 to 1-5 as compared with Comparative Example 1-1. Therefore, from this result, it was confirmed that according to the present invention, it is possible to provide a method for producing a liquid crystal cured film in which bright spots are suppressed and the orientation is excellent. Further, since better results were obtained in Examples 1-1 and 1-2 as compared with Examples 1-3 to 1-5, there is a suitable region in the SP value of the cleaning liquid. It was shown to be doing.

[Example 2-1]
(Preparation of strip-shaped base material)
A long resin film (“ZEONOR” manufactured by ZEON Corporation, thickness 55 μm, SP value = 8.5) formed of norbornene-based resin is cut to a width of 660 mm to obtain a long strip-shaped base material. It was.

(Rubbing process)
The strip-shaped substrate is rubbed in an oblique direction at an angle of 45 ° with respect to the longitudinal direction of the strip-shaped substrate by the same operation as that described in Example C1 of International Publication No. 2016/152685. gave.
Specifically, using the rubbing device C100 schematically shown in FIGS. 6 to 12, the strip-shaped base material obtained in the above step (preparation of the strip-shaped base material) was subjected to a rubbing treatment. At this time, the diameters of the two cylindrical free rolls (grip rolls) C110 and C150 were both set to 80 mm. The diameter of the cylindrical rubbing roll C130 was 120 mm. The axes C11X, C12X, C13X, C14X and C15X of the free roll C110, the floating transfer device C120, the rubbing roll C130, the floating transfer device C140 and the free roll C150 are all in the horizontal direction. Further, the axes C11X and C15X are parallel to the coordinate axis Y, and the swing angles of the axes C12X, C13X and C14X are 45 °. The distance between the axes of the free roll C110 and the free roll C150 is about 1000 mm, the rubbing roll C130 is installed at an intermediate position, and the levitation transport devices C120 and C140 are Cθw12 = 30 °, Cθw13 = 60 °, Cθw14 =. The position was adjusted to 30 °. The carry-in direction of the band-shaped base material C13 carried into the rubbing roll C130 and the carry-out direction of the band-shaped base material C14 carried out from the rubbing roll C130 are the same in the width direction of the band-shaped base material (carry-in at the center in the width direction of the strip-shaped base material or With the carry-out direction as a reference, the angle between the reference direction and another carry-in or carry-out direction is within 0.5 °). The maximum value εmax of the surplus amount of the strip-shaped base material was set to 0.05% or less. Due to such an arrangement, the carrying-out direction of the strip-shaped base material to the rubbing device with respect to the carrying-in direction is a direction without skewing. The line speed for transporting the strip-shaped base material (C11 to C16) was 4 m / min, and the tension was 150 N / m. The rubbing roll C130 was rotated in the reverse direction at 1000 rpm (rotation in the direction indicated by the arrow CR2 in the figure).

(Washing process)
The strip-shaped base material subjected to the rubbing treatment was further continuously conveyed in the longitudinal direction, and immersed in a liquid tank containing ultrapure water (SP value = 23.4) as a cleaning liquid for 30 seconds. As a result, the rubbing-treated surface of the strip-shaped base material was cleaned with the cleaning liquid. Then, the cleaning liquid was removed from the rubbing surface by blowing air with an air knife.

(Formation of liquid crystal cured film)
The liquid crystal composition (L2) prepared in Production Example 2 was applied to the rubbing-treated surface of the strip-shaped base material using a die coater to form a layer of the liquid crystal composition. Next, the layer of the liquid crystal composition was subjected to an orientation treatment of heating at 110 ° C. for 4 minutes to orient the liquid crystal compound contained in the layer. Then, under a nitrogen atmosphere, the layer of the liquid crystal composition was irradiated with ultraviolet rays of 400 mJ / cm ² to be cured, and a liquid crystal cured film having a dry film thickness of 1.7 μm was formed on the rubbing-treated surface of the strip-shaped substrate. As a result, a sample film including a band-shaped base material and a liquid crystal curing film formed on the band-shaped base material was obtained. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Example 2-2]
Immediately before the rubbing treatment, the surface of the strip-shaped base material being conveyed (the surface on the side to be subjected to the rubbing treatment) was subjected to a corona treatment. The strength of the corona treatment was 0.4 kW. The corona-treated strip-shaped substrate was continuously fed to the subsequent rubbing process. Except for the above items, a sample film provided with a strip-shaped base material and a liquid crystal curing film was produced by the same operation as in Example 2-1. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Example 2-3]
As shown in Table 2, the sample film provided with the strip-shaped base material and the liquid crystal curing film was prepared by the same operation as in Example 2-1 except that the type of the cleaning liquid was changed to ethanol (SP value = 12.7). Manufactured. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Example 2-4]
Immediately before the rubbing treatment, the same corona treatment as described in Example 2-2 was applied. In addition, the type of cleaning solution was changed to ethanol (SP value = 12.7) as shown in Table 2. Except for the above items, a sample film provided with a strip-shaped base material and a liquid crystal curing film was produced by the same operation as in Example 2-1. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Examples 2-5 to 2-7]
As shown in Table 2, the types of cleaning liquid are 1,3-dioxolane (SP value = 10.2; Example 2-5), acetone (SP value = 10.0; Example 2-6) or cyclopentanone. A sample film provided with a strip-shaped substrate and a liquid crystal curing film was produced by the same operation as in Example 2-1 except that the value was changed to non (SP value = 10.0; Example 2-7). Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Comparative Example 2-1]
The rubbing treatment on the strip-shaped substrate was carried out by the same operation as that described in Example A1 of International Publication No. 2016/152685. That is, the rubbing treatment on the strip-shaped base material in Comparative Example 2-1 was performed by the same operation as the rubbing treatment in Example 1-1 except that the swing angle of the rubbing roll A130 was changed to 45 °. Further, the rubbing treated surface of the strip-shaped base material was not cleaned with a cleaning liquid. Except for the above items, a sample film provided with a strip-shaped base material and a liquid crystal curing film was produced by the same operation as in Example 2-1. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Comparative Example 2-2]
A sample film provided with the strip-shaped substrate and the liquid crystal curing film was produced by the same operation as in Example 2-1 except that the rubbing-treated surface of the strip-shaped substrate was not cleaned with the cleaning liquid. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Comparative Example 2-3]
Immediately before the rubbing treatment, the same corona treatment as described in Example 2-2 was applied. In addition, the rubbing-treated surface of the strip-shaped substrate was not cleaned with a cleaning liquid. Except for the above items, a sample film provided with a strip-shaped base material and a liquid crystal curing film was produced by the same operation as in Example 2-1. Using this sample film, the liquid crystal cured film contained in the sample film was evaluated by the method described above.

[Results of Examples 2-1 to 2-7 and Comparative Examples 2-1 to 2-3]
The results of Examples 2-1 to 2-7 and Comparative Examples 2-1 to 2-3 are shown in Table 2 below.

[Examination of Examples 2-1 to 2-7 and Comparative Examples 2-1 to 2-3]
From the results in Table 2, it was shown that the number of bright spots can be reduced by cleaning the rubbing-treated surface of the strip-shaped base material. Furthermore, it was clarified that when the corona treatment was carried out as in Examples 2-2 and 2-4, the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film tended to increase. It was. Further, when the behavior of the strip-shaped base material during the experiment was observed, it was found that the case of using the rubbing device provided with the floating transfer device as in Examples 2-1 to 2-7 was from Example 1-1. It was confirmed that the amount of meandering of the strip-shaped base material can be reduced as compared with the case of using a rubbing device not provided with a floating transfer device as in Example 1-5. Here, the "meandering" of the strip-shaped base material means that the strip-shaped base material travels while changing its position in the width direction, and the "meandering amount" represents the fluctuation amount of the above-mentioned position. Further, when the cross section of the liquid crystal cured film obtained in Examples 2-1 to 2-7 was observed with a polarizing microscope, it was found that the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film were hybrid-oriented. confirmed. Specifically, it was confirmed that the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured film was smaller as it was closer to the surface on the strip-shaped substrate side and larger as it was farther from the surface on the strip-shaped substrate side. did.

A11 to A16: Strip-shaped base material A100: Rubbing device A110: Free roll A11X: Shaft A130: Rubbing roll A131: Position on rubbing roll A132: Position on rubbing roll A13X: Shaft A150: Free roll A15X: Shaft Aθw: Holding angle C11 to C16: Strip-shaped base material C100: Rubbing device C110: Free roll C11X: Shaft C120: Floating transfer device C121: Position on the floating transfer device C122: Position on the floating transfer device C123: Transfer section C123S: Transfer surface C124: Air Introduction C12X: Shaft C130: Rubbing roll C131: Position on rubbing roll C132: Position on rubbing roll C13X: Shaft C140: Floating transfer device C141: Position on levitation transfer device C142: Position on levitation transfer device C14X: Axis C150: Free roll C15X: Axis Cθw13: Holding angle Cθw12: Rotation angle of strip-shaped base material Cθw14: Rotation angle of strip-shaped base material

Claims (9)

A method for producing a liquid crystal cured film formed of a cured product of a liquid crystal composition containing a liquid crystal compound capable of exhibiting birefringence of inverse wavelength dispersibility.
The process of rubbing the surface of the base material and
A step of cleaning the surface of the base material that has been subjected to the rubbing treatment with a solvent, and
A step of forming a layer of the liquid crystal composition on the washed surface of the base material, and
A method for producing a liquid crystal cured film, which comprises a step of curing a layer of the liquid crystal composition. The method for producing a liquid crystal cured film according to claim 1, wherein the SP value of the solvent is 12 or more. The method for producing a liquid crystal cured film according to claim 1 or 2, wherein the SP value of the solvent is 24 or less. The method for producing a liquid crystal cured film according to any one of claims 1 to 3, wherein the difference between the SP value of the base material and the SP value of the solvent is 2 or more. The method for producing a liquid crystal cured film according to any one of claims 1 to 4, wherein the substantially maximum inclination angle of the molecule of the liquid crystal compound contained in the liquid crystal cured film is 5 ° or more and 85 ° or less. The method for producing a liquid crystal cured film according to any one of claims 1 to 5, wherein the base material contains an alicyclic structure-containing polymer. The method for producing a liquid crystal cured film according to any one of claims 1 to 6, wherein the base material is long. The method for producing a liquid crystal cured film according to claim 7, wherein the rubbing direction of the rubbing treatment forms an angle of 40 ° or more and 50 ° or less with respect to the longitudinal direction of the base material. The method for producing a liquid crystal cured film according to any one of claims 1 to 8, wherein the base material does not have an alignment film.

Images