JP2002328371A - Method of aligning liquid crystal compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of aligning liquid crystal compound which aligns a liquid crystal compound in a direction different from an extension direction and a rubbing direction by an extension treatment or a rubbing treatment. SOLUTION: The method of aligning liquid crystal compound is characterized in that, by performing a) an extension treatment and esterification treatment for a polymer film having hydroxyl groups, or b) an esterification treatment followed by rubbing treatment for the polymer film, then causing a liquid crystal compound layer to be formed on the polymer film, the liquid crystal compound layer is aligned in the direction different from the extension direction in the case of a), and in the liquid crystal compound layer is aligned in the direction approximately perpendicular to the rubbing-treated film surface in the case of b).

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for aligning a liquid crystal compound and an optical film obtained by the method. More specifically, the present invention relates to a highly oriented liquid crystal having a light control function and suitably used in the field of optoelectronics and the like. The present invention relates to a method for producing a reactive compound and an optical film obtained by the method.

[0002]

2. Description of the Related Art In order to use a liquid crystal compound as an element for controlling light, it is generally necessary to arrange (orient) liquid crystals in a fixed arrangement. It changes under the influence of an external field such as a force or an interface. Then, utilizing the light control function derived from this alignment change, for example, the viewing angle of a liquid crystal display, etc.,
Improvements such as contrast and color change have been made. As a well-known method for orienting the liquid crystal compound in a certain direction, a method of forming a liquid crystal layer on a stretched polymer film and orienting the liquid crystal in the stretch direction of the polymer film (Japanese Patent No. 263015) JP-A-4-
No. 16919) and a method in which an alignment film such as polyimide is subjected to a rubbing treatment to align a liquid crystalline compound in a rubbing direction.

[0003]

However, in the method of aligning a liquid crystalline compound using a stretched polymer film, liquid crystals can be aligned only in the stretching direction. Also,
In many cases, the method of aligning the liquid crystal compound by the rubbing treatment can only align the liquid crystal compound in the rubbing direction (or in the direction perpendicular to the rubbing direction in the plane of the alignment film).

[0004] The present invention aims at aligning a liquid crystalline compound in a direction different from the stretching direction or the rubbing direction, in spite of the orientation method of performing the stretching process or the rubbing process. That is, in the present invention, (1) a polymer film having a hydroxyl group is a) stretched and esterified, or b) esterified and then rubbed, and then a liquid crystal compound layer is formed on the film. By doing
a) aligning the liquid crystal compound in a direction different from the stretching direction, and b) aligning the liquid crystal compound in a direction substantially perpendicular to the rubbed film surface. Method: (2) The orientation direction of the liquid crystal compound layer when a stretching treatment and an esterification treatment are performed on a polymer film having a hydroxyl group is substantially perpendicular to the film surface. (1) The method for aligning a liquid crystalline compound according to (1), and (3) the esterification treatment is performed using a boric acid compound, wherein (1) or (2). (4) the method for aligning a liquid crystalline compound according to (3), wherein the boric acid compound is orthoboric acid; and (5) the polymer film having a hydroxyl group is polyvinyl alcohol or a derivative thereof ( (4) The method for aligning a liquid crystalline compound according to any one of (1) to (4), wherein (6) the polymer film subjected to the stretching treatment and the esterification treatment has a polarizing property. 5) The method for aligning a liquid crystal compound according to any one of 5), (7) a method for forming a liquid crystal compound layer, comprising: a) a polymer film that has been subjected to a stretching treatment and an esterification treatment; Or (b) an alignment method of a liquid crystal compound according to any one of (1) to (6), which is a method of applying the composition on a polymer film that has been subjected to an esterification treatment and then a rubbing treatment, and then drying the applied film. (8) The method for aligning a liquid crystal compound according to any one of (1) to (7), wherein the liquid crystal compound is a thermotropic liquid crystal or a lyotropic liquid crystal, and (9) the liquid crystal compound is nematic in a liquid crystal state. Which is a compound that can take a method oriented according to (8), (10)
(11) The method for aligning a liquid crystal compound according to any one of (1) to (9), wherein the liquid crystal compound is an ultraviolet curable or thermosetting liquid crystal compound, (11) (1) to (10).
(12) An optical film having a liquid crystal compound layer obtained by the method according to any one of (1) to (1).
The optical film according to (11), which has the polymer film obtained by the method according to any one of (0) and (1).
3) An image display device having the optical film according to any one of (11) and (12), and (14) an image display device according to (13), wherein the image display device is a liquid crystal display device.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polymer film used in the present invention is a film having a hydroxyl group, capable of being subjected to an esterification treatment, and capable of being subjected to a stretching treatment or a rubbing treatment. Examples of such a film include a film made of polyvinyl alcohol and a derivative thereof. Derivatives include, for example, a film made of a polymer compound in which a part of polyvinyl alcohol is alkyl-modified, a film made of a polymer compound in which the degree of hydrolysis (degree of saponification) of polyvinyl acetate is changed, and a method in which polyvinyl alcohol is treated with an acid. A film made of a polymer compound partially reacted with a dehydration treatment to form a polyene structure may be used. The degree of polymerization of these polymer films varies depending on the polymer used and ease of film formation. For example, in the case of polyvinyl alcohol, the degree of polymerization is 500 to 50.
About 00 is preferable, and more preferably 1000 to 400
About 0 is good. The stretching ratio when the polymer film is stretched varies depending on the material, but in the case of polyvinyl alcohol, it is preferably 1.5 to 7 times, and more preferably about 2 to 6 times. The stretching is preferably any of uniaxial and biaxial stretching, and more preferably uniaxial stretching. Although the thickness of these polymer films is not particularly limited, it is preferably about 0.05 to 1000 μm, and more preferably about 0.05 to 500 μm. When the polymer film is subjected to a stretching treatment and an esterification treatment, the thickness of the polymer film is preferably 5 to 500 μm, more preferably about 5 to 100 μm, after the stretching treatment.
Most preferably, it is about 10 to 50 μm. When the polymer film is subjected to an esterification treatment and then a rubbing treatment, the thickness of the polymer film is more preferably about 0.05 to 50 μm, and still more preferably about 0.5 to 50 μm.
05-10 μm, most preferably about 0.05-5 μm
About m is good. In this specification, “film” and “membrane” are used with substantially the same meaning, but a relatively thick film is referred to as a “film”, and a relatively thin film is referred to as a “film”. It is also possible.

[0006] The polymer film used in the present invention only needs to be in contact with the treated surface of the film and the liquid crystal compound, and must have sufficient mechanical strength to stably align the liquid crystal compound. Then, a glass plate or another plastic film may be laminated on the surface of the film opposite to the surface where the liquid crystal compound contacts. Examples of such a plastic film include polyethylene terephthalate, polyarylate, polyethylene naphthalate, polybutylene terephthalate, polyether ether ketone, polyethylene, polypropylene, polycarbonate, polystyrene, polyvinylidene chloride, acetyl cellulose, triacetyl cellulose and the like. It is not limited to these. Further, these films may be stretched uniaxially or biaxially. The method of laminating is a method of bonding using various adhesives or adhesives, or preparing a solution of a polymer compound having a hydroxyl group, applying the solution on the above glass plate or plastic film, and then heating and drying the solvent. A method of stacking after removal is given. Examples of the coating method include a microgravure coating method, a gravure coating method, a wire bar coating method, a dip coating method, a spray coating method, and a meniscus coating method.

[0007] The polymer film used in the present invention may be a film having a polarizing property. Polarization is a method of adsorbing a dichroic dye such as a dichroic dye or an iodine polymer in a uniaxially stretched polyvinyl alcohol film and its derivative, or by dehydrating a uniaxially stretched polyvinyl alcohol film with an acid. It can be provided by a method of partially forming a polyene structure.

The esterification treatment performed in the present invention is a treatment for forming an ester by reacting with a hydroxyl group of a polymer film having a hydroxyl group. Examples of such a treatment include a borate ester using a boric acid compound. Treatment, chelation treatment using a titanium compound, acetal using a aldehyde or ketone compound, hemiacetalization treatment, alkoxysilylation treatment using an alkoxysilane compound,
And the like. As a more specific example, regarding esterification treatment using polyvinyl alcohol, Koichi Nagano, Saburo Yamane, Kentaro Toshima co-authored, "Poval"
A so-called gelation reaction described in (Edited by Polymer Publishing Co., Ltd.) corresponds to this. More specific examples include treatment of the stretched polyvinyl alcohol film with orthoboric acid (H3BO3), or treatment of the polyvinyl alcohol film before the rubbing treatment with orthoboric acid (H3BO3).

The conditions and the degree of the esterification treatment are appropriately determined because they differ depending on the polymer film having a hydroxyl group to be used. When the esterification treatment is carried out with orthoboric acid using a polyvinyl alcohol film, the boric acid content in the film is reduced. The amount is 2% or more, preferably 5 to 40
%, More preferably about 10 to 30%. As a specific treatment method, for example, when a polyvinyl alcohol film is used, the film is swollen in warm water of about 30 to 40 ° C. (when a polarizing property is imparted, a dichroic dye or an iodine multimer is further added). After adsorbing), a method of dipping for a certain period of time while stretching in the aqueous solution of boric acid at about 30 to 50 ° C., a method of stretching the film and dipping it in the aqueous solution of boric acid for a certain time, After the film is stretched under heating conditions, the film is similarly treated with a hot aqueous solution of boric acid. Also,
When using a film obtained by applying an aqueous solution of polyvinyl alcohol on a plastic film, and then removing the solvent by heating and drying or the like and laminating the film, on the polyvinyl alcohol film layer of the plastic film on which the polyvinyl alcohol film layer is formed. A method of applying the boric acid aqueous solution and then drying by heating, a method of immersing the plastic film on which the polyvinyl alcohol film layer is formed in the aqueous boric acid solution at about 30 to 50 ° C. for a certain period of time, and then drying by heating. Is mentioned.

The rubbing treatment in the case of performing the rubbing treatment in the present invention means that a velvet-like cloth in which fibers such as rayon, nylon, cotton, and aramid are planted is attached to a roll to produce a rubbing roll, and then the rubbing roll is produced. This is a method of treating the surface of the polymer film by bringing a rubbing roll in one direction into contact with the esterified polymer film while rotating the polymer film at a high speed.
Alternatively, the rubbing treatment can be continuously performed by rotating the high-speed rotating rubbing roll in a fixed state and transporting the esterified polymer film in contact with the rubbing roll. The conditions for the rubbing treatment are as follows: the type of polymer film to be used, the type of plastic film or cloth to be laminated, the diameter of the rubbing roll, the number and direction of rotation of the roll, the moving speed of the polymer film or rubbing roll, and rubbing to the polymer film. It is set as appropriate because it varies depending on the pressing strength of the roll.

The liquid crystalline compound used in the present invention includes a thermotropic liquid crystal which is a compound exhibiting liquid crystallinity in a certain temperature range, and a lyotropic liquid crystal which exhibits liquid crystallinity in a solution of a certain compound in a specific concentration range. Is mentioned. In particular, a thermotropic liquid crystal is often used by mixing a plurality of liquid crystal compounds in order to exhibit liquid crystallinity in a wide temperature range. The liquid crystal compound may have a low molecular weight, a high molecular weight or a mixture thereof, and the liquid crystal state shown is preferably a nematic phase. In order to fix the alignment state, the liquid crystal compound is preferably a compound that is polymerized or cross-linked by ultraviolet light or heat. As such a liquid crystal compound, a compound having a polymerizable group such as a (meth) acryloyl group, an epoxy group, or a vinyl group, or a compound having a crosslinkable functional group such as an amino group or a hydroxyl group is preferable. Such include, for example, W
O97 / 44703 discloses a liquid crystal compound capable of hybrid alignment (when a general alignment film such as polyimide is rubbed and a liquid crystal compound layer is formed on the rubbed surface, the compound becomes an alignment film (A liquid crystal compound having a planar alignment having a slight tilt angle on the side and a substantially homeotropic alignment on the air interface side). These compounds are polymerized or cross-linked in the presence of a polymerization initiator or a cross-linking agent while maintaining the alignment state by ultraviolet light or heat, so that the obtained optically anisotropic material is constant even after a subsequent temperature change. The maintained alignment state can be maintained.

In the present invention, when the liquid crystal compound layer is formed, when the compound can be applied alone, the liquid crystal compound layer is directly applied to the liquid crystal compound layer to thereby obtain a stretched liquid crystal layer. It can be formed on a molecular film or a polymer film which has been subjected to an esterification treatment and further subjected to a rubbing treatment, but can also be applied as a solution. As a solvent for the solution of the liquid crystal compound used in coating, the solvent is excellent in solubility of the compound and wettability to the polymer film during coating, does not disturb the orientation of the liquid crystal phase after drying, and There is no particular limitation as long as the effect of esterification of the film is not lost. As such a solvent, for example, toluene, aromatic hydrocarbons such as xylene, anisole, dioxane, ethers such as tetrahydrofuran, methyl isobutyl ketone,
Ketones such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, and 2,6-dimethyl-4-heptanone; Examples include, but are not limited to, alcohols such as n-butanol, 2-butanol, cyclohexanol and isopropyl alcohol, cellosolves such as methyl cellosolve and methyl cellosolve acetate, and esters such as ethyl acetate, butyl acetate and methyl lactate. The solvent may be a single solvent or a mixture. The concentration at which the liquid crystal compound is dissolved depends on the solubility of the solvent used, the wettability to the polymer film, the thickness after application, etc.
Preferably 5-80% by weight, more preferably 10-70%
% By weight is good. In addition, various leveling agents can be added in order to enhance the wettability of the polymer film and the uniformity of the coating thickness. The type of the leveling agent is not particularly limited as long as it does not disturb the alignment of the liquid crystal.

In the present invention, the method of applying the above liquid crystalline compound onto a stretched polymer film subjected to an esterification treatment or onto a polymer film subjected to an esterification treatment and further subjected to a rubbing treatment is not particularly limited. Since the thickness of the subsequent liquid crystal layer affects the phase difference at the time of tilting, a method capable of applying a uniform thickness is preferable. Examples of such a coating method include a microgravure coating method,
Examples include a gravure coating method, a wire bar coating method, a dip coating method, a spray coating method, a meniscus coating method, and the like. The thickness of the liquid crystal compound layer varies depending on the desired retardation value, and the retardation value varies depending on the birefringence of the compound, but is preferably 0.05 to 20 μm, more preferably 0.1 to 20 μm.
It is about 10 μm.

In the alignment method of the present invention, for example, a solution of a liquid crystalline compound prepared in consideration of solubility and wettability (a polymerization initiator or a crosslinking agent and a leveling agent are added as necessary) is esterified. After applying on the treated stretched polymer film or esterified, and further rubbed polymer film, and then drying by heating, the liquid crystal compound is oriented, and then, if necessary, by ultraviolet light or heat. This is a method of fixing the orientation by polymerization or crosslinking. Conditions for drying by heating and conditions for polymerization or cross-linking by ultraviolet light or heat are appropriately determined in consideration of the type of solvent used, the change in alignment state and the stability of the liquid crystal compound due to the temperature of the liquid crystal compound.

The liquid crystalline compound layer oriented in a direction different from the stretching direction or the rubbing direction obtained by the orientation method of the present invention (for example, a direction substantially perpendicular to the stretched polymer film surface or the rubbing treatment surface) is an ester. An optical film having the polymer film of the present invention can be obtained by using the polymer film integrated with the polymerized stretched polymer film or the esterified and further rubbed polymer film. Further, if it is possible to peel the oriented liquid crystal compound layer from the polymer film, the liquid crystal compound of the present invention can be transferred to another film using an adhesive or an adhesive and used. An optical film having a layer can be obtained.

As a specific example of the optical film having the stretched polymer film of the present invention obtained by integrating and using the stretched polymer film subjected to the esterification treatment, the stretched polymer film may be a retardation film. In this case, the retardation characteristics (for example, a change in retardation value with a viewing angle) of an esterified stretched polymer film alone in which a liquid crystal compound layer oriented in a certain direction is directly formed on the retardation plate are different. A retardation film having characteristics is exemplified. Also,
When the stretched polymer film is a film having a polarizing property as described above, a polarizing plate having a liquid crystal compound layer oriented in a certain direction directly on the polarizing film may be mentioned. In this case, as in the prior art, a process of forming a liquid crystal compound layer by orienting it on another film, and then bonding the liquid crystal compound layer to a polarizing plate made of a stretched polymer film sandwiched with triacetyl cellulose on both sides with an adhesive or the like. It is possible to reduce the thickness and simplification of the process as compared with the case of the first embodiment.

When the liquid crystalline compound layer obtained by the method of the present invention is substantially vertically aligned and has a positive uniaxial property in the thickness direction, it has a negative uniaxial property in the thickness direction. Since the change in the phase difference value due to the inclination of the optically anisotropic member can be compensated, it can be applied to various optical elements. Therefore, for example, by laminating a film having a negative uniaxial property to the thickness direction such as a cholesteric liquid crystal film and a liquid crystal compound layer that is substantially vertically aligned, a viewing angle characteristic which is one form of the optical film of the present invention is provided. Can improve the cholesteric liquid crystal film. Further, by laminating this film and a 波長 wavelength plate, a non-absorbing polarizing plate having improved viewing angle dependency, which is one mode of the optical film of the present invention, can be obtained. Further, to form a liquid crystal compound layer that is substantially vertically aligned on the polarizing film,
By laminating a 波長 wavelength plate and further a cholesteric liquid crystal film, a polarizing plate having a wide viewing angle and a high contrast, which is one form of the optical film of the present invention, which is useful for a liquid crystal display or the like and has improved use efficiency of a backlight. Obtainable. Further, a retardation film, which is an embodiment of the optical film of the present invention obtained by laminating a liquid crystal compound layer that is substantially vertically aligned and a retardation film that is uniaxially stretched, has a tilt.
The change in retardation value due to (viewing angle) can be a change in retardation value different from the change in retardation value due to tilt in a uniaxially stretched retardation film.

When the liquid crystal compound layer oriented in a certain direction is peeled off and used, for example, in combination with another retardation plate, its slow axis (or fast axis) and the liquid crystal compound phase The relationship with the optical axis may affect the optical characteristics when both are laminated.
Therefore, in such a case, for example, the retardation plate and the predetermined optical axis are arranged so as to be bonded together with an adhesive or the like, and then the stretched polymer film or the rubbed high By peeling from the molecular film, an optical film having a liquid crystal compound layer of the present invention can be obtained. At this time, the polymer film after peeling can be reused as long as the ability to align the liquid crystal compound is not reduced.

The optical film obtained in the present invention is used for various image display devices such as a liquid crystal display, a plasma display, and an electroluminescence display to improve, for example, a viewing angle characteristic, a contrast characteristic, an antireflection characteristic and the like. The image display device of the present invention can be obtained. When used in a liquid crystal display, for example, the optical film of the present invention is arranged so as to sandwich the liquid crystal cell to obtain desired characteristics, or the backlight side, or the optical film of the present invention is arranged only on the observer side Thereby, the liquid crystal display device of the present invention can be obtained.
In particular, by using the optical film of the present invention integrated with a polarizing plate, the conventional, stretched polymer film on both sides of the polarizing plate sandwiched by triacetyl cellulose and a case where a film having another liquid crystal compound layer is laminated. Compared with this, it is possible to reduce the thickness and simplify the process.

[0020]

The present invention will now be described more specifically with reference to examples. Example 1 A polyvinyl alcohol film having a thickness of 75 μm and a degree of polymerization of 2400 was uniaxially stretched 5 times in a 3% boric acid aqueous solution at 50 ° C., washed with water and dried while maintaining the tension state, and dried to a thickness of about 20 μm. A stretched polymer film treated with boric acid (H3BO3) was obtained. The boric acid content in the polyvinyl alcohol of this film was 13.5%. Next, WO9
No. 7/44703, when a liquid crystal compound having a hybrid alignment described above (when a general alignment film made of a mixture of the following compounds, such as polyimide, is subjected to rubbing treatment and a liquid crystal compound layer is formed on the rubbed surface) UV-curable liquid crystalline compound exhibiting a nematic liquid crystal phase in which the compound has a planar alignment with a slight tilt angle on the alignment film side and is almost homeotropically aligned on the air interface side)

[0021]

Embedded image

23.5 parts by weight, and

[0023]

Embedded image

70.5 parts by weight and 6 parts by weight of a photopolymerization initiator Irgacure 907 (manufactured by Ciba Geigy) are dissolved in a mixed solvent of 130 parts by weight of toluene and 55.7 parts by weight of cyclohexanone, and the solid content concentration is 35%. Was prepared.
This solution is applied using a wire bar on the stretched polymer film bonded to a glass plate using an adhesive under the condition that the film thickness after drying is about 1 μm, and the solvent is removed by heating. Thereafter, the mixture was irradiated with a high-pressure mercury lamp (80 W / cm) and polymerized to form a liquid crystal compound layer of the present invention. Next, the obtained liquid crystal compound layer was transferred onto a triacetyl cellulose film coated with an adhesive to obtain an optical film having a liquid crystal compound layer of the present invention. Before the transfer of the optical film, the change in the phase difference value when the film is inclined from the direction perpendicular to the film surface of the stretched polyvinyl alcohol to the direction perpendicular to the stretching direction and the stretching direction can be measured by an automatic birefringence meter (Oji Measuring instrument company: KOBRA-21A
It measured using D). The results are shown in FIG. In addition, only a liquid crystal compound layer is transferred using a glass plate coated with an adhesive, and a change in retardation value when the film is inclined from a direction perpendicular to the film surface is also measured by an automatic birefringence meter (Oji It was measured using a measuring instrument company: KOBRA-21AD). The results are shown in FIG.

Example 2 An iodine-based polarizing plate (Polytechno Co., Ltd., degree of polymerization: 1700, thickness of about 20 μm after stretching; boric acid (H3BO3) content in polyvinyl alcohol: about 15%; saponified triacetyl cellulose film on one side) The liquid crystal compound layer of the present invention was formed in the same manner as in Example 1, except that only the adhesive layer bonded with a polyvinyl alcohol-based adhesive was used. The change in the phase difference due to the tilt angle of the obtained liquid crystal compound layer was measured in the same manner as in Example 1. The results are shown in FIG. The same method as in Example 1 was used to transfer only the liquid crystal compound layer using a glass plate coated with an adhesive, and similarly change the retardation value when tilted from a direction perpendicular to the film surface. Was measured by The results are shown in FIG.

Example 3 A 1% aqueous solution of polyvinyl alcohol (Gohsenol NH26, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was applied onto a saponified triacetyl cellulose film and dried at 70 ° C. Next, a 0.1% boric acid (H3BO3) aqueous solution was applied on the triacetyl cellulose film having the polyvinyl alcohol film, and dried at 70 ° C.
Further, a rubbing roll having a roll diameter of 50 mm in which a polyvinyl alcohol film surface of the triacetyl cellulose film having the boric acid-treated polyvinyl alcohol film is wound with a rubbing cloth made of rayon (YA-20-R: manufactured by Yoshikawa Kako Co., Ltd.). Rubbing roll rotation speed: 200 m / min. Contact length with a triacetyl cellulose film having a polyvinyl alcohol film treated with boric acid, 3 mm, conveying speed of the film:
1 m / min. A rubbing treatment was performed under the following conditions. Next, a mixture of the liquid crystalline compounds (23.5 parts by weight of the compound of the formula (1) and 70.5 parts by weight of the compound of the formula (2)) used in Example 1 and a photopolymerization initiator Irgacure 907 (Ciba-Geigy) 6 parts by weight) were dissolved in a mixed solvent of 130 parts by weight of toluene and 55.7 parts by weight of cyclohexanone to prepare a solution having a solid concentration of 35% by weight. This solution was rubbed, on a rubbed polyvinyl alcohol film surface of a triacetyl cellulose film having a boric acid-treated polyvinyl alcohol film, using a wire bar, the film thickness after drying was about 1 μm. After coating under such conditions and removing the solvent by heating, the mixture was irradiated with a high-pressure mercury lamp (80 W / cm) and polymerized to obtain an optical film having a liquid crystal compound layer of the present invention. Automatic birefringence for the change of the phase difference value when the optical film is inclined from the direction perpendicular to the surface of the triacetyl cellulose film having the polyvinyl alcohol film to the rubbing direction and the direction perpendicular to the rubbing direction before the transfer of the optical film. Measuring instrument (Oji Scientific Instruments: KOBRA-21A)
It measured using D). The results are shown in FIG. Further, only the liquid crystalline compound layer was transferred using a glass plate coated with an adhesive, and the change in retardation value when the film was inclined from a direction perpendicular to the film surface was similarly measured as in Example 1. It was measured by the method. The results are shown in FIG.

Comparative Example A rubbing treatment was performed on the polyvinyl alcohol film surface of a polyvinyl alcohol film laminated on a saponified triacetyl cellulose film in the same manner as in Example 3 except that a 0.1% boric acid (H3BO3) aqueous solution was not used. ,
Next, a liquid crystal compound layer was formed. The change in the phase difference due to the tilt angle of the obtained liquid crystal compound layer was measured in the same manner as in Example 3. The results are shown in FIG. The same method as in Example 1 was used to transfer only the liquid crystal compound layer using a glass plate coated with an adhesive, and similarly change the retardation value when tilted from a direction perpendicular to the film surface. Was measured by The results are shown in FIG.

As can be seen from Examples 1 and 2, the orientation of the liquid crystal compound layer is different from the stretching direction by the orientation method of the present invention, even though the stretched polymer is used. It turns out that it has a substantially vertical alignment (homeotropic alignment). Further, as can be seen from Example 3 and Comparative Example, the alignment method of the present invention makes the entire liquid crystal compound layer different from the rubbing direction and has a substantially vertical alignment (homeotropic alignment) with respect to the film surface. You can see that.

[0029]

According to the present invention, a polymer film having a hydroxyl group is subjected to a) a stretching treatment and an esterification treatment, or b) an esterification treatment and then a rubbing treatment, and then a liquid crystal compound layer is formed on the film.
The present invention is characterized in that the liquid crystal compound is oriented in a direction different from the stretching direction in the case of a) and in a direction substantially perpendicular to the rubbed film surface in the case of b). By using the liquid crystal compound alignment method, useful for various optical elements, a liquid crystal compound layer oriented in a direction different from the stretching direction, or substantially perpendicular to the rubbed polymer film surface, An optical film having a compound layer can be produced.

[Brief description of the drawings]

FIG. 1 shows a change in retardation depending on the tilt angle of a liquid crystal compound layer obtained in Example 1 of the present invention.

FIG. 2 shows a change in phase difference depending on an inclination angle when the liquid crystal compound layer obtained in Example 1 of the present invention is transferred to a glass plate coated with an adhesive.

FIG. 3 shows a change in a phase difference depending on an inclination angle of a liquid crystal compound layer obtained in Example 2 of the present invention.

FIG. 4 shows a change in a phase difference depending on an inclination angle when the liquid crystal compound layer obtained in Example 2 of the present invention is transferred to a glass plate coated with an adhesive.

FIG. 5 shows a change in retardation depending on the tilt angle of the liquid crystalline compound layer obtained in Example 3 of the present invention.

FIG. 6 shows a change in phase difference depending on an inclination angle when the liquid crystal compound layer obtained in Example 3 of the present invention is transferred to a glass plate coated with an adhesive.

FIG. 7 shows a change in a phase difference depending on an inclination angle of a liquid crystal compound layer obtained in a comparative example.

FIG. 8 shows a change in a phase difference depending on an inclination angle when the liquid crystal compound layer obtained in the comparative example is transferred to a glass plate coated with an adhesive.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 510 G02F 1/1335 510 1/13363 1/13363 // C08L 29:04 C08L 29:04 Z

Claims (14)

[Claims] 1. A polymer film having a hydroxyl group is obtained by a) stretching treatment and esterification treatment, or b) esterification treatment and then rubbing treatment, and then forming a liquid crystal compound layer on the film.
The liquid crystal compound is characterized in that the liquid crystal compound is oriented in a direction different from the stretching direction in the case of a) and in a direction substantially perpendicular to the rubbed film surface in the case of b). Orientation method. (2) that the orientation direction of the liquid crystal compound layer when the stretching treatment and the esterification treatment are performed on the polymer film having a hydroxyl group is substantially perpendicular to the film surface. The method for aligning a liquid crystal compound according to claim 1, wherein: 3. The method for aligning a liquid crystalline compound according to claim 1, wherein the esterification treatment is performed using a boric acid compound. 4. The method for aligning a liquid crystal compound according to claim 3, wherein the boric acid compound is orthoboric acid. 5. The method for aligning a liquid crystalline compound according to claim 1, wherein the polymer film having a hydroxyl group is polyvinyl alcohol or a derivative thereof. 6. The polymer film subjected to the stretching treatment and the esterification treatment has a polarizing property.
6. The method for aligning a liquid crystal compound according to any one of items 5 to 5. 7. A method for forming a liquid crystal compound layer comprises the steps of: (a) stretching and esterifying a polymer film;
7. The method for aligning a liquid crystalline compound according to claim 1, wherein the method is a method of b) applying the composition on a polymer film that has been subjected to an esterification treatment and then a rubbing treatment, and then drying the applied polymer film. 8. The method for aligning a liquid crystal compound according to claim 1, wherein the liquid crystal compound is a thermotropic liquid crystal or a lyotropic liquid crystal. 9. The method for aligning a liquid crystal compound according to claim 8, wherein the liquid crystal compound is a compound capable of forming a nematic phase in a liquid crystal state. 10. The method for aligning a liquid crystal compound according to claim 1, wherein the liquid crystal compound is an ultraviolet-curable or thermosetting liquid-crystal compound. 11. An optical film having a liquid crystalline compound layer obtained by the method according to claim 1. 12. The optical film according to claim 11, which has a polymer film obtained by the method according to any one of claims 1 to 10. 13. An image display device comprising the optical film according to claim 11. 14. The image display device according to claim 13, wherein the image display device is a liquid crystal display device.