TW201722998A - Method for manufacturing liquid crystal alignment film, liquid crystal alignment film, liquid crystal display element, polymer, and liquid crystal aligning agent - Google Patents

Abstract

Provided are a method for manufacturing a liquid crystal alignment film having high light utilization efficiency, a liquid crystal alignment film, and a liquid crystal display element. The liquid crystal aligning agent of the present invention is prepared by polymerizing polysiloxane and a monomer having liquid crystal properties, a photosensitive group, and a radical polymerizable group to obtain a polymer. After a side-chain-type polymer film (1) is obtained from the liquid crystal aligning agent, an aligning process is performed by irradiating polarized ultraviolet rays, then the product is heated, and side chains (2) of the side-chain-type polymer film (1) are realigned. A liquid crystal alignment film is then fabricated by heating the product at a higher temperature to fix the realigned state. The temperature of heating for realignment is 200 DEG C or lower, for example, or another temperature ranging from 10 DEG C higher than the lower limit of the temperature range at which the side-chain-type polymer film (1) exhibits liquid crystal properties to 10 DEG C lower than the upper limit of this temperature range. A liquid crystal display element is manufactured using the resultant liquid crystal alignment film.

Description

Method for producing liquid crystal alignment film, liquid crystal alignment film, liquid crystal display element, polymer and liquid crystal alignment agent

The present invention relates to a polymer, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element which are suitable for a method for producing a highly efficient liquid crystal alignment film using light.

The liquid crystal display element is known as a lightweight, thin, and low-power display device. In recent years, the use for large-sized televisions has been rapidly developed.

The liquid crystal display element is composed of, for example, a liquid crystal layer sandwiched between a pair of substrates having transparent electrodes. In such a liquid crystal display element, an organic film made of an organic material is used as a liquid crystal alignment film, and the liquid crystal is placed between the substrates in a desired alignment state.

In other words, the constituent members of the liquid crystal alignment film-type liquid crystal display element are formed on the surface in contact with the liquid crystal of the liquid crystal substrate, and serve to align the liquid crystal in a predetermined direction between the substrates.

Further, the liquid crystal alignment film may have a function of controlling the liquid crystal in addition to a function of aligning the liquid crystal in a direction parallel to the direction of the substrate. The function of the tilt (Pretiltangle). The ability to control the alignment of the liquid crystal in the liquid crystal alignment film (hereinafter referred to as the alignment control energy) is imparted by the alignment treatment of the organic film constituting the liquid crystal alignment film.

A method of aligning a liquid crystal alignment film for imparting alignment control, for example, a conventional rubbing method is known. The rubbing method refers to an organic film such as polyvinyl alcohol, polyamide or polyimide on a substrate, and the surface thereof is wiped (frictionally) in a certain direction by a cloth such as cotton, nylon, or polyester. A method of aligning a liquid crystal in a direction (friction direction) after wiping. This rubbing method is simple and can realize the alignment state of the relatively stable liquid crystal, and thus is used in the process of the conventional liquid crystal display element. The organic film for a liquid crystal alignment film mainly selects a polyimine-based organic film which is excellent in reliability or electrical properties such as heat resistance.

However, the rubbing method of wiping the surface of the liquid crystal alignment film composed of polyimide or the like has a problem of generating dust or static electricity. In addition, due to the high definition of the liquid crystal display element in recent years, the unevenness caused by the switching of the active element on the substrate or the liquid crystal driving, the surface of the liquid crystal alignment film cannot be uniformly wiped with a cloth, and uniformity may not be achieved. LCD alignment.

Therefore, the optical alignment method is being actively reviewed for the other alignment treatment method of the liquid crystal alignment film which is not rubbed.

The photo-alignment method has several methods of forming anisotropy in an organic film constituting a liquid crystal alignment film by linearly polarized or collimated light, and the liquid crystal is aligned according to the anisotropy.

The main photo-alignment method is known, for example, for decomposing photo-alignment methods. For example, a polarized ultraviolet ray is irradiated onto a polyimide film, and a molecular structure is utilized. A method of aligning the liquid crystal by dissolving the anisotropic decomposition of the ultraviolet ray, and dispersing the remaining polyimine to align the liquid crystal (see, for example, Patent Document 1).

Further, a photo-alignment type or a photo-isomerization type photo-alignment method is also known. For example, polyvinyl cinnamate is used, and then polarized ultraviolet rays are irradiated, and a double bond of two side chains parallel to the polarized light is generated to generate a dimerization reaction (crosslinking reaction) to align the liquid crystal in a direction orthogonal to the polarization direction ( For example, Non-Patent Document 1). Further, when a side chain type polymer having a side chain having azobenzene is used, a polarized ultraviolet ray is irradiated to cause an isomerization reaction of the azobenzene portion of the side chain parallel to the polarized light, and the liquid crystal is aligned in the direction of polarization. The direction of intersection (see, for example, Non-Patent Document 2).

In addition, in the light distribution method, the technique of combining the light irradiation treatment and the heating step to improve the alignment control energy of the liquid crystal alignment film has been examined (see, for example, Patent Documents 2 to 4).

In the above example, the alignment treatment method of the liquid crystal alignment film by the photo-alignment method utilizes a reaction of light such as a photocrosslinking reaction or a photoisomerization reaction. Therefore, materials which can be used to form a liquid crystal alignment film require photoreactivity which can carry out the reaction. For example, in the above Non-Patent Document 1, a polyvinyl cinnamate can be used as the material of the liquid crystal alignment film.

Further, as described above, the liquid crystal alignment film requires excellent reliability and the like. Therefore, as described above, the liquid crystal alignment film which has been subjected to the rubbing treatment is a polyimine-based organic film which is excellent in reliability and electrical properties such as heat resistance. Therefore, even in the liquid crystal alignment film by the photoalignment method, photoreactivity and reliability can be achieved.

Recently, in the field of polymer materials, for example, a polymer material obtained by polymerizing an acrylic polymer and a siloxane polymer, and mixing them to obtain a highly reliable polymer material such as an acrylic acid-oxynane mixed material has been known ( For example, Patent Documents 5 to 9).

However, it has to be used for the photoreaction, and in the field of the liquid crystal alignment film of the photoalignment method, such a highly reliable mixed material or the like has not yet been introduced.

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3893659

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-304215

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2007-232934

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-276149

[Patent Document 5] Japanese Patent Laid-Open No. Hei 7-243173

[Patent Document 6] Japanese Patent Laid-Open Publication No. Hei 9-208642

[Patent Document 7] Japanese Patent Laid-Open No. Hei 4-261454

[Patent Document 8] Japanese Patent Laid-Open Publication No. 2003-313233

[Patent Document 9] Japanese Patent Laid-Open No. Hei 1-168971

[Non-patent literature]

[Non-Patent Document 1] M. Shadt et al., Jpn. J. Appl. Phys. 31, 2155 (1992)

[Non-Patent Document 2] K. Ichimura et al., Chem. Rev. 100, 1847 (2000)

[Summary of the Invention]

As described above, the photo-alignment method has a great advantage in that it does not require a rubbing step as a rubbing method which has been industrially used as an alignment treatment method for a liquid crystal display element. For example, a substrate having a liquid crystal display element having a concavo-convex surface may be subjected to an alignment treatment to form an alignment treatment method for a liquid crystal alignment film which is suitable for industrial production processes. Further, the light alignment method can change the irradiation amount of the polarized light, and the alignment control energy can be controlled as compared with the rubbing alignment control.

However, in order to achieve the same degree of alignment control energy as the rubbing method, the photo-alignment method requires a large amount of light irradiation after polarization, and in addition to low efficiency, stable liquid crystal alignment may not be achieved.

For example, in the decomposition type photo-alignment method described in Patent Document 1, it is necessary to irradiate the ultraviolet ray of a high-pressure mercury lamp of 500 W for 60 minutes on the polyimide film, and it takes a long time and a large amount of ultraviolet ray irradiation. Further, in the case of the dimerization type or the photoisomerization type photo-alignment method, a large amount of ultraviolet irradiation of a few J (Joules) to several tens of J may be required. Further, in the photo-crosslinking type or the photo-isomerization type photo-alignment method, since the thermal stability or the light stability of the liquid crystal alignment is inferior, there is a problem that alignment failure or display burnt occurs when the liquid crystal display element is used.

As described above, the technique of combining the light irradiation treatment and the heating step to improve the alignment control energy of the liquid crystal alignment film is also examined. However, the material has a problem of heat resistance, or when the heat resistance is insufficient, the solvent solubility is extremely poor.

Further, in order to have both photoreactivity and reliability, a material for a sufficient photo-alignment method has not yet been developed.

Therefore, since the photo-alignment method can achieve high efficiency of alignment treatment and stable liquid crystal alignment, it is necessary to develop a method for producing a liquid crystal alignment film which can provide an alignment control property excellent in liquid crystal alignment film with high efficiency. Further, the method for producing the liquid crystal alignment film is preferably carried out using a highly reliable polymer.

An object of the present invention is to provide a method for producing a liquid crystal alignment film using light and a liquid crystal alignment film, and to provide a liquid crystal display element having the obtained liquid crystal alignment film.

Further, an object of the present invention is to provide a polymer suitable for a method for producing a highly efficient liquid crystal alignment film using light and a liquid crystal alignment agent containing the polymer.

In other words, the present invention has the following technical features.

(1) A method for producing a liquid crystal alignment film, comprising: a step of forming a side chain type polymer film exhibiting liquid crystallinity in a predetermined temperature range on a substrate; [I], the side chain type a step of irradiating the polarized light ultraviolet light to the polymer film [II], and heating the side chain type polymer film after the ultraviolet light irradiation at a temperature within a range in which the side chain type polymer film exhibits liquid crystallinity [III] And heating the aforementioned side chain polymer film to the heating temperature of the step [III] Step [IV] of heating at a temperature above the degree.

(2) The method for producing a liquid crystal alignment film according to the above item 1, wherein the heating temperature in the step [III] is higher than the lower limit of the temperature range in which the side chain type polymer film exhibits liquid crystallinity by 10 ° C to the liquid crystal. The upper limit of the temperature range is lower than the temperature of 10 °C.

(3) The method for producing a liquid crystal alignment film according to the above item (1) or (2), wherein the heating temperature of the step [III] is a temperature of 200 ° C or lower.

(4) The method for producing a liquid crystal alignment film according to any one of the items (1) to (3), wherein the heating temperature of the step [III] is a temperature at which the side chain of the side chain type polymer film is realigned. .

(5) The method for producing a liquid crystal alignment film according to any one of the items (1) to (4), wherein the heating temperature of the step [III] is a temperature at which the side chain of the side chain type polymer film is realigned. The heating temperature of the step [IV] is such that the re-alignment of the step [III] is carried out.

(6) The method for producing a liquid crystal alignment film according to any one of the above (1), wherein the photosensitive group contained in the side chain type polymer film exhibiting the liquid crystal property is represented by At least one selected from the group consisting of azobenzene, diphenylethylene, cinnamic acid, cinnamate, chalcone, coumarin, tolan, and phenyl benzoate group.

(7) The method for producing a liquid crystal alignment film according to any one of the above aspects, wherein the side chain type polymer film contains polyamic acid, polyimine, and polyamine. a main chain composed of at least one selected from the group consisting of an acid ester, an acrylate, a methacrylate, a maleimide, an α-methylene-γ-butyrolactone, and a decane a structure of at least one side chain selected from the group consisting of the following formulas (1) to (5), (7), and (8),

(In the formula (1), A ₁ and B ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. Y ₁ system a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, which are bonded to each other independently of each other -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl, or alkoxy. X ₁ represents a single bond, -COO-, -OCO- , -N=N-, -CH=CH-, -C≡C-, or C ₆ H _{4 -.} 11 represents an integer from 1 to 12, m1 represents an integer from 1 to 3, and n1 represents 1 to 12 The integer.

In the formula (2), A ₂ , B ₂ and D ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. Y ₂ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl, or alkoxy. X ₂ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -. R ₁ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The 12 series represents an integer from 1 to 12, the m2 represents an integer from 1 to 3, and the n2 represents an integer from 1 to 12.

In the formula (3), A ₃ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. X ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -, and R ₂ represents a hydrogen atom or a carbon number of 1~ 6 alkyl. The 13 series represents an integer from 1 to 12, and the m3 represents an integer from 1 to 3.

In the formula (4), the 14 series represents an integer of 1 to 12.

In the formula (5), A ₄ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. X ₄ represents -COO-. Y ₃ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a combination thereof, and the hydrogen atom bonded to each of them is independently -NO ₂ , -CN, -CH=C(CN ₂ , -CH=CH-CN, halo, alkyl or alkoxy substituted. The 15 series represents an integer from 1 to 12, and the m4 represents an integer from 1 to 3.

In the formula (7), A ₅ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. R ₃ represents a hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. a group consisting of or a combination thereof. The 16 series represents an integer from 1 to 12. The hydrogen atom of the benzene ring bonded to the formula (7) can be independently independently -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group, or an alkane. Oxygen substitution.

In the formula (8), A ₆ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. B ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -. W ₁ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy, 17 represents an integer from 1 to 12, m ₅ and m _{The 6} series each independently represent an integer from 1 to 3).

The method for producing a liquid crystal alignment film according to any one of the above aspects, wherein the side chain type polymer film contains a polyoxyalkylene having a radical polymerizable group (a) A polymer obtained by radical polymerization of a monomer having a liquid crystal property and a photosensitive group and a radical polymerizable group (b).

(9) The method for producing a liquid crystal alignment film according to the above item (8), wherein the liquid crystalline and photosensitive group of the monomer (b) is composed of azobenzene or stilbene. , cinnamic acid, cinnamate, chalcone, coumarin, diphenyl At least one selected group selected from the group consisting of tolan and phenyl benzoate.

(10) A liquid crystal alignment film produced by the method for producing a liquid crystal alignment film according to any one of the items (1) to (9) above.

(11) A liquid crystal display element characterized by having the liquid crystal alignment film of the above (10).

(12) A polymer characterized in that a polysiloxane having a radical polymerizable group (a) and a monomer having a liquid crystal property and a photosensitive group and a radical polymerizable group (b) are free Base polymerization.

(13) The polymer according to the above item (12), wherein the polyoxyalkylene (a) is a polyfluorene obtained by polycondensing an alkoxysilane having an alkoxydecane of the following formula (10). Alkane, R ¹³ _s1 Si(OR ¹⁴ ) _s2 (10)

(In the formula (10), R ¹³ is an alkyl group substituted with an acryloyl group, a methacryl fluorenyl group, a styryl group or an aryl group. R ¹⁴ represents hydrogen or an alkyl group having 1 to 5 carbon atoms. S1 is 1 Or 2, S2 is 2 or 3).

(14) The polymer according to the above item (12) or (13), wherein the liquid crystalline and photosensitive group of the monomer (b) is azobenzene, diphenylethylene, cinnamic acid or cinnamic acid. At least one selected group selected from the group consisting of esters, chalcone, coumarin, diphenylacetylene, and benzoate.

The polymer of any one of the above-mentioned items (12) to (14), wherein the monomer (b) has a hydrocarbon, an acrylate, a methacrylate, a maleimide, and A polymerizable group composed of at least one selected from the group consisting of α-methylene-γ-butyrolactone (Butyrolactone) and the following formula (1) to formula (5), formula (7) and formula ( 8) at least one of the side chain monomers selected in the group,

(In the formula (1), A ₁ and B ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. Y ₁ system a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, which are bonded to each other independently of each other -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy. X ₁ represents a single bond, -COO-, -OCO-, - N=N-, -CH=CH-, -C≡C- or C ₆ H _{4 -.} 11 represents an integer from 1 to 12, m1 represents an integer from 1 to 3, and n1 represents an integer from 1 to 12.

In the formula (2), A ₂ , B ₂ and D ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. Y ₂ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy. X ₂ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -. R ₁ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The 12 series represents an integer from 1 to 12, the m2 represents an integer from 1 to 3, and the n2 represents an integer from 1 to 12.

In the formula (3), A ₃ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. X ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -. R ₂ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The 13 series represents an integer from 1 to 12, and the m3 represents an integer from 1 to 3.

In the formula (4), the 14 series represents an integer of 1 to 12.

In the formula (5), A ₄ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. X ₄ represents -COO-. Y ₃ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a combination thereof, and the hydrogen atom bonded to each of them can be independently -NO ₂ , -CN, -CH=C(CN ₂ , -CH=CH-CN, halo, alkyl or alkoxy substituted. The 15 series represents an integer from 1 to 12, and the m4 represents an integer from 1 to 3.

In the formula (7), A ₅ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. R ₃ is a hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. Or a group consisting of a combination thereof. The 16 series represents an integer from 1 to 12. The hydrogen atom bonded to the benzene ring in the formula (7) can be independently independently -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group or an alkoxy group. Substituted.

In the formula (8), A ₆ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-. B ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -. W ₁ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy. The 17 series represents an integer from 1 to 12, and the m ₅ and m ₆ systems each independently represent an integer from 1 to 3).

(16) The polymer according to any one of the above items (12) to (15), wherein the monomer (b) is used in an amount relative to the alkoxydecane 1 when the polyoxyalkylene (a) is obtained. Moor, 0.5 to 50 moles.

(17) A liquid crystal alignment agent comprising the polymer according to any one of the items (12) to (16) above.

The side chain type polymer film of the present invention may be a side chain structure having no photoreactivity in a range in which liquid crystallinity and photoreactivity are not lost. Use the structure contained.

A side chain structure which does not have photoreactivity, for example, has a structure of the following formula (6).

In the above formula (6), E ₁ represents a single bond, -O-, -CH ₂ -, -COO, -OCO-, -CONH- or -NH-CO-.

Z represents a single bond, -COO, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -.

K1 represents an integer from 1 to 12, and p1 and q1 each independently represent an integer from 0 to 3.

R ₄ represents a hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkoxy group having 1 to 6 carbon atoms, a carboxyl group, or a combination thereof. Group.

According to the present invention, a liquid crystal alignment film having a high-efficiency alignment treatment can realize an alignment treatment using high efficiency of light, thereby obtaining a liquid crystal alignment film, and a liquid crystal display element including the liquid crystal alignment film can be obtained.

Further, according to the present invention, a polymer which can be applied to the liquid crystal alignment film as described above and a liquid crystal alignment agent containing the polymer can be obtained.

1,3,5,7‧‧‧Side chain polymer film

2, 2a, 2b, 4, 4a, 4b, 6, 6a, 8, 8a‧‧‧ side chain

FIG. 1 is a schematic explanatory view showing an introduction process of anisotropy in a method for producing a liquid crystal alignment film according to a first aspect of the present invention, and (a) shows a state of a side chain type polymer film before polarized light irradiation. (b) is a view showing a state of a side chain type polymer film after polarized light irradiation, (c) is a view showing a state of a side chain type polymer film after heating, and (d) is a second stage after heating. A diagram of the state of the side chain type polymer film which is fixed by the heat treatment.

FIG. 2 is a schematic explanatory view showing a process of introducing a non-uniformity in a method for producing a liquid crystal alignment film according to a first aspect of the present invention, and (a) is a view showing a state of a side chain type polymer film before polarized light irradiation. (b) is a view showing a state of the side chain type polymer film after the polarized light irradiation, (c) is a view showing a state of the side chain type polymer film after heating, and (d) is a second heat treatment after heating. A view showing a state of a side chain type polymer film in which alignment is fixed.

FIG. 3 is a schematic explanatory view showing a process of introducing the non-uniformity in the method for producing a liquid crystal alignment film according to the second aspect of the present invention. (a) is a view showing a state of a side chain type polymer film before polarized light irradiation, (b) is a view showing a state of a side chain type polymer film after polarized light irradiation, and (c) is a side chain type polymer after heating. A diagram of the state of the membrane.

FIG. 4 is a schematic explanatory view showing a process of introducing a non-uniformity in a method for producing a liquid crystal alignment film according to a second aspect of the present invention, and (a) is a view showing a state of a side chain type polymer film before polarized light irradiation. (b) is a view showing a state of the side chain type polymer film after the polarized light irradiation, and (c) is a view showing a state of the side chain type polymer film after heating.

[Fig. 5] The spectrum of the polarization electric field of the liquid crystal alignment film obtained in Example 4 for the ultraviolet light to be irradiated is a parallel and vertical ultraviolet absorption spectrum.

6 is a graph showing the parallel and vertical ultraviolet absorption spectra of the polarized electric field spectrum of the ultraviolet ray to be irradiated by the liquid crystal alignment film obtained in Example 6.

As a result of intensive studies by the present inventors, the following findings have been found, and the present invention has been completed.

The method for producing a liquid crystal alignment film of the present invention uses a side chain type polymer film which exhibits liquid crystallinity, and does not require rubbing treatment, and utilizes a bias A method of performing alignment treatment by light irradiation.

The side chain type polymer film which exhibits the liquid crystallinity is a monomer which has a radical polymerizable group, a polyoxyalkylene (a), a liquid crystal-sensitive photosensitive group, and a radical polymerizable group. (b) Formed by a polymer obtained by radical polymerization.

After the polarized light irradiation, a step of heating the side chain type polymer film is provided to produce a liquid crystal alignment film. At this time, the heating step is two stages of the first heating step and the second heating step having different temperatures. Further, the irradiation temperature of the polarized light and the heating temperature of the first heating step after the polarized light irradiation are optimized, and a highly efficient alignment treatment can be realized in the liquid crystal alignment film. Then, the alignment state in which the liquid crystal alignment film is formed is fixed by the second heating step. As a result, the present invention can achieve high efficiency and impart good alignment control energy to the liquid crystal alignment film.

The invention is described in detail below.

<Side chain type polymer (polymer) and side chain type polymer film>

The side chain type polymer film which exhibits liquid crystallinity used in the method for producing a liquid crystal alignment film of the present invention is a side chain type polymer which exhibits liquid crystallinity in a predetermined temperature range, that is, a polymer. Membrane. Further, the side chain bonded to the main chain of the polymer is photosensitive, and the induced light generates a crosslinking reaction, an isomerization reaction, or a photo Fries rearrangement.

The photosensitive group bonded to the main chain is not particularly limited, and is preferably an inductive light, which produces a cross-linking reaction or a light-Fretz rearrangement of the knot. Structure. At this time, even if it is in the external stress of heat or the like, the achieved alignment control energy can be stably maintained for a long period of time.

In the method for producing a liquid crystal alignment film of the present invention, a structure of a side chain type polymer film which exhibits liquid crystallinity in a predetermined temperature range is used, and is not particularly limited as long as it satisfies such characteristics. The side chain structure of the side chain type polymer preferably has a straight mesogenic composition. At this time, when the side chain type polymer is used for a liquid crystal alignment film, a stable liquid crystal alignment can be obtained.

The structure of the side chain type polymer, for example, has a main chain and a side chain bonded to the main chain, and a side chain thereof has a biphenyl group, a triphenyl group, a phenylcyclohexyl group, a phenyl benzoate group. a liquid crystal component such as an azobenzene group and a structure capable of inducing light at a front end portion, generating a photosensitive group of a crosslinking reaction or an isomerization reaction, or a side chain having a main chain and a bond with the main chain. The side chain thereof has a liquid crystal composition and has a structure in which a phenyl benzoate group of a light-Foles rearrangement reaction is generated.

In addition, the side chain type polymer film which exhibits liquid crystallinity, which is used in the method for producing a liquid crystal alignment film of the present invention, is sometimes referred to as a side chain type polymer film which exhibits liquid crystallinity. Or simply referred to as a side chain type polymer film of the present invention.

Specific examples of the side chain type polymer film which exhibits liquid crystallinity of the present invention contain acrylate, methacrylate, maleimide, α-methylene-γ-butyrolactone , oxoxane, itaconate, fumarate, maleate, styrene, ethylene, maleimide, norbornene, polylysine, polyimine, polyamine Formate, polyamine, A main chain composed of at least one selected from the group consisting of a polyether and a polyphthalate is selected from the group consisting of the following formulas (1) to (5), (7), and (8). The structure of at least one side chain is preferred.

In the above formula (1), A ₁ and B ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-.

Y ₁ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl, or alkoxy.

X ₁ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C-, or C ₆ H ₄ -.

The 11 series represents an integer from 1 to 12, the m1 represents an integer from 1 to 3, and the n1 represents an integer from 1 to 12.

In the above formula (2), A ₂ , B ₂ and D ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-.

Y ₂ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl, or alkoxy.

X ₂ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -.

R ₁ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

The 12 series represents an integer from 1 to 12, the m2 represents an integer from 1 to 3, and the n2 represents an integer from 1 to 12.

In the above formula (3), A ₃ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-.

X ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -, and R ₂ represents a hydrogen atom or a carbon number of 1~ 6 alkyl.

The 13 series represents an integer from 1 to 12, and the m3 represents an integer from 1 to 3.

In the above formula (4), 14 represents an integer of 1 to 12.

In the above formula (5), A ₄ represents a single bond, -O-, -CH ₂ - , -COO-, -OCO-, -CONH- or -NH-CO-.

X ₄ represents -COO-.

Y ₃ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a combination thereof, and the hydrogen atom bonded to each of them is independently -NO ₂ , -CN, -CH=C(CN ₂ , -CH=CH-CN, halo, alkyl or alkoxy substituted.

The 15 series represents an integer from 1 to 12, and the m4 represents an integer from 1 to 3.

In the above formula (7), A ₅ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-.

R ₃ represents a hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. a group consisting of or a combination thereof.

The 16 series represents an integer from 1 to 12.

The hydrogen atom of the benzene ring bonded to the formula (7) can be independently independently -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group, or an alkane. Oxygen substitution.

In the above formula (8), A ₆ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-.

B ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -.

W ₁ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, and is bonded to each of the hydrogen atom systems thereof. Independently substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy.

The 17 series represents an integer from 1 to 12, and the m ₅ and m ₆ systems each independently represent an integer of 1 to 3.

The side chain represented by the above formulas (1) to (5), (7) and (8) has a biphenyl group, a triphenyl group, a phenylcyclohexyl group, a phenyl benzoate, an azo group. A group such as benzene is a structure of a liquid crystal component. In addition, the front end portion can induce light, generate a dimerization reaction, has a photosensitive group having a crosslinking reaction or a side chain having a main chain and a bond with the main chain, and a side chain thereof becomes a liquid crystal component, and has a light-emission. The phenyl benzoate group of the Rice rearrangement reaction, or a group having at least any one of them.

The side chain type polymer film which exhibits the liquid crystallinity of the present invention may be selected from the group consisting of the above main chain and the group consisting of the above formulas (1) to (5), (7) and (8). At least one of the side chains and a structure which can be used in combination with a side chain structure having no photoreactivity in a range in which liquid crystallinity or photoreactivity is not lost.

A side chain structure which does not have photoreactivity, for example, has a structure of the following formula (6).

In the above formula (6), E ₁ represents a single bond, -O-, -CH ₂ -, -COO, -OCO-, -CONH- or -NH-CO-.

Z represents a single bond, -COO, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -.

K1 represents an integer from 1 to 12, and p1 and q1 each independently represent 0~3. The integer.

R ₄ represents a hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkoxy group having 1 to 6 carbon atoms, a carboxyl group or a combination thereof. group.

<polyoxane (a)>

In the following, the polyoxyalkylene (a) having a radical polymerizable group for forming a photosensitive side chain type polymer film which exhibits liquid crystallinity, which is used in the method for producing a liquid crystal alignment film of the present invention, will be described.

The polysiloxane (a) used as a material of the side chain type polymer film contains a polyoxyalkylene obtained by polycondensation of an alkoxysilane having an alkoxydecane represented by the following formula (10).

R ¹³ _s1 Si(OR ¹⁴ ) _s2 (10)

In the above formula (10), R ¹³ is an alkyl group substituted with an acryl fluorenyl group, a methacryl fluorenyl group, a styryl group or an aryl group.

R ¹⁴ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

S1 is 1 or 2, and S2 is 2 or 3.

R ¹³ (hereinafter also referred to as a second specific organic group) of the alkoxydecane represented by the above formula (10) is selected from the group consisting of an acryl fluorenyl group, a methacryl fluorenyl group, a styryl group, and an aryl group. At least one base-substituted alkyl group. The number of hydrogen atoms to be substituted is one or more, preferably one.

The carbon number of the alkyl group is preferably from 1 to 30, more preferably from 1 to 20. More preferably, it is 1~10. The alkyl group may be linear or branched, and is preferably linear.

It represents the above formula (10) alkoxy silane-based carbon number of R ¹⁴ an alkyl group of 1 to 5, preferably 1 to 3 carbon atoms, particularly preferably 1 to 2 carbon atoms.

Specific examples of the alkoxydecane represented by the above formula (10) are not limited thereto.

The alkoxydecane represented by the above formula (10) is, for example, 3-methylpropenyloxypropyltrimethoxydecane, 3-methylpropenyloxypropyltriethoxydecane, or methacrylonitrile. Oxymethyltrimethoxydecane, methacryloxymethyltriethoxydecane, 3-propenyloxypropyltrimethoxydecane, 3-propenyloxypropyltriethoxydecane, Acryloxyethyltrimethoxydecane, Acryloxyethyltriethoxydecane, Styrylethyltrimethoxydecane, Styrylethyltriethoxydecane, 3-( N-styrylmethyl-2-aminoethylamino)propyltrimethoxydecane.

In the production of the polyoxyalkylene (a), in addition to the alkoxysilane represented by the above formula (10), the effect of the present invention is not impaired in order to improve adhesion to the substrate, affinity with liquid crystal molecules, and the like. Within the range, one or a plurality of alkoxydecanes represented by the following formula (11) can be used. The alkoxydecane represented by the following formula (11) can impart various properties to the polyoxyalkylene. Therefore, one or a plurality of kinds can be optionally used in combination with necessary characteristics.

(R ¹⁸ ) _n Si(OR ¹⁹ ) _4-n (11)

In the above formula (11), the R ¹⁸ hydrogen atom or the carbon number which may be substituted by a hetero atom, a halogen atom, an amine group, a glycidoxy group, a thiol group, an isocyanate group or a urea group is 1 to 10 carbon atoms. Hydrocarbyl group.

In the above formula (11), R ¹⁹ is a C 1 to 5 carbon number, preferably an alkyl group having 1 to 3 carbon atoms.

In the above formula (11), n is 0 to 3, preferably an integer of 0 to 2.

The R ¹⁸ hydrogen atom or the hydrocarbon group having 1 to 10 carbon atoms (hereinafter also referred to as a third specific organic group) of the alkoxydecane represented by the above formula (11).

a third specific organic group such as an aliphatic hydrocarbon group; a hydrocarbon group having an aromatic ring, an aromatic ring and a heterocyclic ring structure; a hydrocarbon group having an unsaturated bond; and a hetero atom which may contain an oxygen atom, a nitrogen atom, a sulfur atom or the like, A hydrocarbon group having a branched structure and having a carbon number of 1 to 6. Further, the third specific organic group may be substituted by a halogen atom, an amine group, a glycidoxy group, a thiol group, an isocyanate group or a ureido group or the like.

Specific examples of the alkoxydecane represented by the above formula (11) are as follows, but are not limited thereto. For example, 3-(2-aminoethylaminopropyl)trimethoxydecane, 3-(2-aminoethylaminopropyl)triethoxydecane, 2-aminoethylaminomethyl Trimethoxy decane, 2-(2-aminoethyl thioethyl) triethoxy decane, 3-hydrothiopropyl triethoxy decane, thiomethyl methyl trimethoxy decane, vinyl Triethoxy decane, 3-isocyanate propyl triethoxy decane, trifluoropropyltrimethoxy decane, chloropropyl triethoxy decane, bromopropyltriethoxy decane, 3-hydrogenthio Bupropyltrimethoxydecane, dimethyldiethoxydecane, dimethyldimethoxydecane, diethyldiethoxydecane, diethyldimethoxydecane, diphenyldimethoxydecane , diphenyldiethoxydecane, 3-aminopropylmethyldiethoxydecane, 3-aminopropyldimethylethoxydecane, trimethylethoxydecane, trimethylmethyl Oxydecane, γ-ureidopropyltriethoxydecane, γ-ureidopropyltrimethoxydecane, and γ-ureidopropyltripropoxydecane Wait.

In the alkoxydecane represented by the above formula (11), the alkoxydecane-based tetraalkoxydecane in which n is 0. The tetraalkoxydecane is easily condensed with the alkoxydecane represented by the formula (10), and thus the polyoxyalkylene (a) used in the present invention can be obtained, which is preferable.

In the formula (11), the alkoxydecane wherein n is 0 is more preferably tetramethoxynonane, tetraethoxydecane, tetrapropoxydecane or tetrabutoxydecane, particularly preferably tetramethoxy. Decane or tetraethoxydecane.

In the present invention, the alkoxydecane represented by the formula (10) preferably contains 1 to 30 mol%, particularly preferably 5, of the peralkoxydecane used in the production of the polyoxyalkylene (a). ~20% by mole.

<monomer (b)>

The monomer (b) for forming a photosensitive side chain type polymer film which exhibits liquid crystallinity used in the method for producing a liquid crystal alignment film of the present invention is liquid crystalline, and has a photosensitive group and radical polymerization. Sexual basis.

The liquid crystal property of the monomer (b), and the photosensitive group is azobenzene, diphenylethylene, cinnamic acid, cinnamic acid ester, chalcone, coumarin, diphenylacetylene and phenylbenzene At least one of the groups derived from the group of acid esters.

For example, the monomer (b) preferably has at least one selected from the group consisting of hydrocarbons, acrylates, methacrylates, maleimide, and α-methylene-γ-butyrolactone. At least one side chain selected from the group consisting of the above formulas (1) to (5), (7), and (8) Monomer.

The monomer (b) is used together with the above polyoxyalkylene (a) to form a polymer, which can be used to form the side chain type polymer film of the present invention.

<Manufacture of side chain type polymer>

The side chain type polymer in the side chain type polymer film of the present invention contains the monomer (b) having the above polysiloxane (a) and a liquid crystal-sensitive photosensitive group and a radical polymerizable group. The polymer obtained by radical polymerization is carried out.

The polymer is, for example, a polysiloxane (a) and a monomer having a liquid crystal property and a photosensitive group and a radical polymerizable group (b) in a solvent in which a polymerization initiator or the like is present, at 50 to 110 ° C. The polymerization reaction is carried out at a temperature.

The amount of the monomer (b) to be used is preferably from 0.5 to 50 moles, more preferably from 1 to 10 moles, per mole of the alkoxydecane when the polyoxane (a) is obtained.

The solvent to be used in the case of obtaining a polymer is a polymerization initiator which is added as long as it dissolves polysiloxane (a) and a liquid crystal-sensitive photosensitive group and a radical polymerizable group (b). When the agent is the same, there is no particular limitation. Specific examples of the solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl stilbene acetate, ethyl stilbene acetate, diethylene glycol monomethyl ether, and diethylene glycol. Monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-butanone, 3- Methyl-2-pentyl Ketone, 2-pentanone, 2-heptanone, γ-butyrolactone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropanoate, ethyl ethoxyacetate, ethyl hydroxyacetate , methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-ethoxypropane Methyl ester, pyruvic acid methyl ester, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, N,N-di Methylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, and the like.

The above polymerization initiators are, for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azo An azo compound such as bis-(4-methoxy-2,4-dimethylvaleronitrile), benzamidine peroxy, lauryl peroxide, t-butyl peroxytrimethyl acetate, An organic peracid such as 1,1'-bis-(t-butylperoxy)cyclohexane or hydrogen peroxide. Among them, azobisisobutyronitrile (AIBN) is preferred, for example.

The content of the polymerization initiator is 1 to 3 mol%, more preferably 5 to 30 mol%, based on 1 mol of the above monomer (b).

<Method for Producing Liquid Crystal Alignment Film>

Next, a method of producing the liquid crystal alignment film of the present invention will be described.

In the method for producing a liquid crystal alignment film of the present invention, the side chain type polymer is used, and after the coating film is formed on the substrate, the polarized ultraviolet rays are irradiated. By the first heating, the high-efficiency non-uniformity is introduced into the side chain type polymer film, and the second heating is performed, and the liquid crystal alignment with excellent alignment control of the liquid crystal is produced. membrane.

In more detail, the side of the side chain type polymer film is used. The light reaction in the chain polymer and the principle of molecular reorientation by self-organization based on liquid crystallinity realize high-efficiency non-uniformity introduction into the side chain type polymer film.

Further, in the method for producing a liquid crystal alignment film of the present invention, when a photocrosslinkable group is used as a photoreactive group of a side chain type polymer, the side chain type polymer is used to form a coating film on the substrate. After that, the polarized ultraviolet light is irradiated to perform the first alignment treatment, and the side chain type polymer film is subjected to the first heating (also referred to as the first heating treatment) at a temperature within a range in which liquid crystallinity is exhibited. 2 Re-alignment processing of alignment processing.

After the re-alignment treatment is performed, the second heating (also referred to as the second heating treatment) is performed at a temperature equal to or higher than the temperature of the first heating, and the contained polyoxyalkylene structural portion is condensed. In addition, in the second heat treatment, the unevenness introduced into the side chain type polymer film is fixed by light irradiation and the first heat treatment, whereby a highly efficient liquid crystal alignment film can be produced, and a high-efficiency liquid crystal alignment film can be produced. A highly reliable liquid crystal alignment film based on a polyoxymethane structure.

The method for producing a liquid crystal alignment film of the present invention has more specifically the following steps. [I] a step of forming a side chain type polymer film exhibiting liquid crystallinity in a predetermined temperature range on a substrate, and [II] irradiating the side chain type polymer film obtained in the step [I] with a polarized light a step of ultraviolet rays, [III] a step of heating the side chain type polymer film after the polarized ultraviolet irradiation in the step [II], and [IV] a side chain polymer film heated in the step [III] And steps [III] Steps of reheating at different temperatures.

Hereinafter, the present invention which is a side chain type polymer having a photoreactive group having a photocrosslinkable group is referred to as a first embodiment, and a structure having a photo-refluence rearrangement group as a photoreactive group is used. The present invention of the side chain type polymer is referred to as a second aspect, and reference is made to Figs. 1 (a) to (d), Figs. 2 (a) to (d), Figs. 3 (a) to (c), and Fig. 4 (a). ~(c) Further explanation.

As shown in Fig. 1 (a) to (d), in the method for producing a liquid crystal alignment film according to the first aspect of the present invention, the heterogeneous introduction treatment of the side chain type polymer film is carried out, wherein the step [II] When the amount of ultraviolet irradiation is in the range of 1 to 15% of the ultraviolet irradiation amount which is the maximum ΔA, first, the side chain type polymer film 1 of the present invention is formed on the substrate. As shown in Fig. 1(a), the side chain type polymer film 1 formed on the substrate has a structure in which the side chains 2 are randomly arranged. The liquid crystal component and the photosensitive group of the side chain 2 are also randomly arranged according to the random arrangement of the side chain 2 of the side chain type polymer film 1, and the side chain type polymer film 1 is isotropy.

Here, ΔA means the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet light and the ultraviolet absorbance in the vertical direction in the side chain type polymer film of the present invention.

As shown in Fig. 2 (a) to (d), in the method for producing a liquid crystal alignment film according to the first aspect of the present invention, the heterogeneous introduction treatment of the side chain type polymer film is carried out, wherein the step [II] When the amount of ultraviolet irradiation is in the range of 15 to 70% of the ultraviolet irradiation amount which is the maximum ΔA, first, the side chain type polymer film 3 of the present invention is formed on the substrate. As shown in Figure 2(a), The side chain type polymer film 3 formed on the substrate has a structure in which the side chains 4 are randomly arranged. The liquid crystal component and the photosensitive group of the side chain 4 are also randomly arranged according to the random arrangement of the side chains 4 of the side chain type polymer film 3, and the side chain type polymer film 2 is uniform.

As shown in Fig. 3 (a) to (c), in the method for producing a liquid crystal alignment film according to the second aspect of the present invention, the heterogeneous introduction treatment of the side chain type polymer film is carried out by using the above formula (7). When the liquid crystal alignment film of the side chain type polymer having a structure of a photo-Fres rearrangement is used, the ultraviolet irradiation amount of the step [II] is the ultraviolet irradiation amount with the maximum ΔA When it is in the range of 1 to 70%, first, the side chain type polymer film 5 is formed on the substrate. As shown in FIG. 3(a), the side chain type polymer film 5 formed on the substrate has a structure in which the side chains 6 are randomly arranged. The liquid crystal component and the photosensitive group of the side chain 6 are also randomly arranged according to the random arrangement of the side chains 6 of the side chain type polymer film 5, and the side chain type polymer film 5 is uniform.

As shown in Fig. 4 (a) to (c), in the method for producing a liquid crystal alignment film according to the second aspect of the present invention, the heterogeneous introduction treatment of the side chain type polymer film is carried out by using the above formula (8). When the liquid crystal alignment film of the side chain type polymer having a structure of a light-Frys rearrangement is used, the ultraviolet irradiation amount of the step [II] is 1 to 70% of the ultraviolet irradiation amount which is the maximum with ΔA. In the range, first, the side chain type polymer film 7 is formed on the substrate. As shown in Fig. 4 (a), the side chain type polymer film 7 of the present embodiment formed on a substrate has a structure in which the side chains 8 are randomly arranged. According to the random arrangement of the side chains 8 of the side chain type polymer film 7, the liquid crystal composition of the side chain 8 and The photosensitive groups are also randomly arranged, and the side chain type polymer film 7 is uniform.

As shown in Fig. 1 (a) to (d), in the first aspect of the present invention, when the ultraviolet irradiation amount of the step [II] is in the range of 1 to 15% of the ultraviolet irradiation amount which is the largest ΔA, When the polarized ultraviolet light is irradiated with the polarized ultraviolet light, as shown in FIG. 1(b), the side chain 2 having the photosensitive group is arranged in the side chain 2 which is arranged in parallel with the polarization direction of the ultraviolet light. The photosensitive group of 2a preferentially generates a photoreaction such as a dimerization reaction. As a result, the density of the side chain 2a which causes photoreaction becomes high only in the direction in which the ultraviolet ray is irradiated, and as a result, the side chain type polymer film 1 is given a very small unevenness.

As shown in Fig. 2 (a) to (d), in the first aspect of the present invention, in the case where the ultraviolet irradiation amount in the step [II] is in the range of 15 to 70% of the ultraviolet irradiation amount which is the largest ΔA, When the polarized ultraviolet light is irradiated to the side chain type polymer film 3, as shown in FIG. 2(b), the side chain 4 which is arranged in parallel with the polarization direction of the ultraviolet light has a side chain of a photosensitive group. The photosensitive group of 4a preferentially generates a photoreaction such as a dimerization reaction. As a result, the density of the side chain 4a which causes the photoreaction becomes higher in the polarization direction of the ultraviolet ray, and as a result, a small anisotropy is imparted to the side chain type polymer film 3.

As shown in Fig. 3 (a) to (c), in the second aspect of the present invention, when a liquid crystal alignment film having a side chain type polymer having a light-Frys rearrangement structure is used, When the ultraviolet irradiation amount of the step [II] is in the range of 1 to 70% of the ultraviolet irradiation amount with the maximum ΔA, the side chain type polymer film 5 of the uniformity is irradiated with the polarized light. In the case of ultraviolet rays, as shown in FIG. 3(b), in the side chain 6 which is arranged in parallel with the direction in which the ultraviolet light is polarized, the photosensitive group having the photosensitive group side chain 6a preferentially generates light such as light-Fles rearrangement. reaction. As a result, the density of the side chain 6a which causes photoreaction becomes high only in the direction in which the ultraviolet ray is irradiated, and as a result, very small anisotropy is imparted to the side chain type polymer film 5.

As shown in Fig. 4 (a) to (c), in the second aspect of the present invention, when a liquid crystal alignment film having a side chain type polymer having a structure of a light-Frys rearrangement is used, When the ultraviolet irradiation amount of the step [II] is in the range of 1 to 70% of the ultraviolet irradiation amount which is the maximum ΔA, the polarized ultraviolet ray is irradiated to the side chain type polymer film 7 of the uniformity. As shown in FIG. 4(b), in the side chain 8 which is arranged in parallel with the direction in which the ultraviolet light is polarized, the photosensitive group of the side chain 8a having the photosensitive group preferentially generates a photoreaction such as light-Fretz rearrangement. As a result, the density of the side chain 8a which causes photoreaction becomes higher in the direction in which the ultraviolet ray is irradiated, and as a result, the side chain type polymer film 7 is given a small unevenness.

Next, in the first aspect of the present invention, as shown in Figs. 1 (a) to (d), in the case where the ultraviolet irradiation amount in the step [II] is in the range of 1 to 15% of the ultraviolet irradiation amount which is the maximum ΔA The side chain type polymer film 1 after the polarized ultraviolet irradiation is heated to form a liquid crystal state. As shown in Fig. 1(c), the side chain type polymer film 1 is different in the amount of crosslinking reaction which occurs between the direction parallel to the direction in which the ultraviolet rays are irradiated and the direction perpendicular to the vertical direction. At this time, the amount of the crosslinking reaction generated in the direction parallel to the direction in which the ultraviolet light is irradiated is extremely small, and therefore, the crosslinking reaction site serves as a plasticizer. Therefore, liquid crystallinity perpendicular to the direction of polarization of the ultraviolet light The liquid crystallinity higher than the parallel direction is self-organized in a direction parallel to the direction in which the ultraviolet light is irradiated, and the side chain 2 containing the liquid crystal component is realigned. As a result, the very small asymmetry of the side chain type polymer film 1 caused by the photocrosslinking reaction is increased by heat, and the side chain type polymer film 1 is imparted with greater heterogeneity.

Similarly, in the first aspect of the present invention, as shown in Figs. 2(a) to 2(d), the ultraviolet irradiation amount in the step [II] is in the range of 15 to 70% of the ultraviolet irradiation amount which is the maximum ΔA. At the time, the side chain type polymer film 3 after the polarized light irradiation is heated to form a liquid crystal state. As shown in Fig. 2(c), the side chain type polymer film 3 is different in the amount of crosslinking reaction which occurs between the direction parallel to the direction in which the ultraviolet rays are irradiated and the direction perpendicular to the vertical direction. Therefore, self-organization is performed in a direction parallel to the direction in which the ultraviolet light is irradiated, and the side chain 4 containing the liquid crystal component is realigned. As a result, the small anisotropy of the side chain type polymer film 3 caused by the photocrosslinking reaction is increased by heat, and the side chain type polymer film 3 is imparted with greater heterogeneity.

Similarly, in the second aspect of the present invention, as shown in FIGS. 3(a) to 3(c), a liquid crystal of a side chain type polymer having a structure of a light-Frys rearrangement group using the above formula (7) is used. In the alignment film, when the ultraviolet irradiation amount in the step [II] is in the range of 1 to 70% of the ultraviolet irradiation amount which is the maximum ΔA, the side chain type polymer film 5 after the polarized light irradiation is heated to form a liquid crystal state. . As shown in FIG. 3(c), the side chain type polymer film 5 is different between the direction parallel to the direction in which the ultraviolet rays are irradiated and the direction perpendicular to the vertical direction, and the amount of the light-Flys rearrangement reaction is different. At this time, the light generated by the direction perpendicular to the direction in which the ultraviolet light is irradiated is the liquid of the Fres rearrangement body. Since the crystal alignment force is larger than the liquid crystal alignment force of the side chain before the reaction, it is self-organized in the direction perpendicular to the polarization direction of the ultraviolet ray, and the side chain 6 containing the liquid crystal component is realigned. As a result, the very small anisotropy of the side chain type polymer film 5 induced by the light-Flys rearrangement reaction is increased by heat, and the side chain type polymer film 5 is given a larger unevenness. Directional.

Similarly, in the second aspect of the present invention, as shown in FIGS. 4(a) to 4(c), a liquid crystal of a side chain type polymer having a structure of a light-Frys rearrangement group using the above formula (8) is used. In the alignment film, when the ultraviolet irradiation amount in the step [II] is in the range of 1 to 70% of the ultraviolet irradiation amount which is the maximum ΔA, the side chain type polymer film 7 after the polarized light irradiation is heated to form a liquid crystal state. When the side chain type polymer film 7 is between the direction parallel to the polarizing direction of the ultraviolet ray and the perpendicular direction, the amount of the light-Freak rearrangement reaction generated differs as shown in Fig. 4(c). The anchoring force of the light-Flys rearrangement body 8(a) is greater than the side chain 8 before the rearrangement, and therefore, when a certain amount of light-Freed rearrangement body is generated, it is irradiated with ultraviolet rays. The polarizing direction is self-organized in the parallel direction, and the side chain 8 containing the liquid crystal component is realigned. As a result, the small anisotropy of the side chain type polymer film 7 caused by the light-Flys rearrangement reaction is increased by heat, and the side chain type polymer film 7 is given a larger unevenness. Sex.

Further, in the first aspect of the present invention, the side chain type polymer has a polyoxyalkylene structure derived from the polyoxyalkylene (a). Therefore, as shown in FIG. 1(c) or FIG. 2(c), the side chain type polymer film of the present invention is structured by the self-organization of the liquid crystal to induce anisotropy, and the polyoxyalkylene structure is used. The temperature generated by the thermal reaction (crosslinking reaction) The second heat treatment can fix the heterogeneity. In other words, the side chain type polymer film of the present invention can be caused by the alignment direction of the side chain 2b or the side chain 4b by the second heat treatment as shown in Fig. 1 (d) or Fig. 2 (d). Larger anisotropy is immobilized. The temperature of the second heat treatment is preferably a temperature generated by a thermal reaction of a siloxane, and may be, for example, a temperature of 200 ° C or higher.

In the second aspect of the present invention, the side chain type polymer also has a polyoxyalkylene structure derived from the polyoxyalkylene (a). Therefore, the side chain type polymer film of the present invention is self-organized by liquid crystal as shown in FIG. 3(c) or FIG. 4(c), and after the heterogeneity is induced, the polypyroxyline structure is The temperature generated by the thermal reaction (crosslinking reaction) is subjected to a second heat treatment to immobilize the heterogeneity. In other words, although the side chain type polymer film of the present invention is not shown, similarly to the first aspect, the unevenness caused by the large heat treatment can be fixed by the second heat treatment. The temperature of the second heat treatment is preferably the temperature at which the thermal reaction of the decane is caused, as in the first embodiment, and may be, for example, a temperature of 200 ° C or higher.

Therefore, the method for producing a liquid crystal alignment film of the present invention is carried out by sequentially performing a first heat treatment for ultraviolet light irradiation and realignment after polarization of the side chain type polymer film, and a second heat treatment for immobilization. A liquid crystal alignment film into which non-uniformity is introduced is obtained with high efficiency.

Further, in the method for producing a liquid crystal alignment film of the present invention, the amount of ultraviolet rays irradiated by the opposite side chain type polymer film and the heating temperature in the first heat treatment and the second heat treatment are optimized for each purpose. Thereby, high efficiency can be achieved to introduce the heterogeneity into the side chain type polymer film.

The high-efficiency non-uniformity of the side chain type polymer film of the present invention is introduced into an optimum amount of polarized ultraviolet light in the side chain type polymer film to cause the photosensitive group to undergo photocrosslinking reaction or The amount of the photoisomerization reaction or the light-Freak rearrangement reaction is the optimum amount of the polarized ultraviolet light.

When the side chain type polymer film of the present invention is irradiated with the polarized ultraviolet light, when the photolinking reaction or the photoisomerization reaction or the light-Freak rearrangement reaction has less photosensitive groups in the side chain, it is impossible to A sufficient amount of photoreaction is obtained. At this time, sufficient self-organization is not performed even after heating.

In the side chain type polymer film of the present invention, as a result of irradiating the polarized ultraviolet light to the structure having a photocrosslinkable group, crosslinking of the side chain is caused when the photosensitive group of the side chain of the crosslinking reaction becomes excessive. The reaction will go on excessively. At this time, the obtained film becomes rigid, and even if it is heated later, it hinders the progress of self-organization.

Further, in the side chain type polymer film of the present invention, as a result of irradiating the polarized ultraviolet light to the structure having the light-Flese rearrangement group, the photosensitive group of the side chain of the light-Flys rearrangement reaction becomes When the excess is excessive, the liquid crystallinity of the side chain type polymer film is lowered too low. At this time, the liquid crystallinity of the obtained film is also lowered, and even after heating, the progress of self-organization is hindered.

Further, when the polarized ultraviolet light is irradiated to the structure having the light-Frees rearrangement base, the side chain type polymer of the present invention is photodecomposed when the amount of ultraviolet light is excessively irradiated, and even if heated, the self-organization is hindered. In progress.

Therefore, in the side chain type polymer film of the present invention, polarized light The irradiation of ultraviolet rays, the photosensitive group of the side chain in the photocrosslinking reaction or the photoisomerization reaction or the light-Freak rearrangement reaction is the optimum amount of the photosensitive group of the side chain type polymer film. ~40 mole% is preferred. More preferably 0.1 to 20 mol%. When the amount of the photosensitive group in the side chain of the photoreaction is in the above range, the self-organization of the subsequent heat treatment can be performed with higher efficiency, and high-efficiency non-uniformity can be formed in the film.

The method for producing a liquid crystal alignment film of the present invention is a photocrosslinking reaction or photoisomerization reaction of a photosensitive group in a side chain of a side chain type polymer film by optimizing the amount of ultraviolet light irradiated by the polarized light. Or the amount of light-Freak rearrangement reaction is optimized. Further, together with the subsequent heat treatment, it is possible to achieve high efficiency and introduce the non-uniformity into the side chain type polymer film. At this time, the amount of the preferable polarized ultraviolet rays can be determined in accordance with the evaluation of the ultraviolet absorption of the side chain type polymer film.

In other words, in the side chain type polymer film of the present invention, ultraviolet absorption in the direction parallel to the polarization direction of the polarized ultraviolet light and ultraviolet absorption in the vertical direction after the polarized ultraviolet light irradiation are measured. From the measurement results of the ultraviolet absorption, the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet light and the ultraviolet absorbance in the vertical direction in the side chain type polymer film, that is, ΔA was evaluated. Further, in the side chain type polymer film of the present invention, the maximum value (ΔAmax) of ΔA to be realized and the amount of irradiation of polarized ultraviolet rays at which the value is realized are obtained.

In the method for producing a liquid crystal alignment film of the present invention, the amount of polarized ultraviolet light which is irradiated at the time of production of the liquid crystal alignment film can be determined based on the amount of polarized ultraviolet light which achieves the ΔAmax.

In the method for producing a liquid crystal alignment film of the present invention, it is preferred to set the amount of the polarized ultraviolet light of the side chain type polymer film to be in the range of 1 to 70% of the amount of the polarized ultraviolet light of ΔAmax. It is in the range of 1~50%.

In the side chain type polymer film of the present invention, the amount of the polarized ultraviolet ray in the range of 1 to 50% of the amount of the polarized ultraviolet ray of ΔAmax is equivalent to the photosensitive group of the side chain type polymer film. 0.1 to 20 mol% of the whole amount of polarized ultraviolet light for photocrosslinking reaction.

Next, in the method for producing a liquid crystal alignment film of the present invention, after the side chain type polymer film is irradiated with polarized ultraviolet rays, the side chain type polymer film is heated (first heat treatment).

The side chain type polymer film of the present invention is a polymer film which exhibits liquid crystallinity within a predetermined temperature range.

The first heat treatment after the polarized ultraviolet ray irradiation can be determined based on the temperature at which the liquid crystallinity of the side chain type polymer film is exhibited. In other words, the heating temperature of the first heat treatment after the polarized ultraviolet ray irradiation is a temperature within a range in which the side chain type polymer film of the present invention exhibits liquid crystallinity. Further, the heating temperature after the polarized ultraviolet ray irradiation is higher than the lower limit of the liquid crystal temperature range to a temperature higher than the lower limit of the liquid crystal temperature range, which is 10 ° C higher than the lower limit of the temperature range in which the side chain type polymer film exhibits liquid crystallinity (hereinafter referred to as the liquid crystal temperature range). The temperature in the range of 10 ° C is preferred.

The side chain type polymer film of the present invention is subjected to polarized ultraviolet light irradiation, heated to a liquid crystal state, and self-organized and realigned in parallel with the polarizing direction or in the vertical direction. Results photocrosslinking reaction or photoisomerization The small anisotropy of the side chain type polymer film which is caused by the light-Freak rearrangement reaction is increased by heat. However, when the side chain type polymer film exhibits a liquid crystal state by heating, when the heating temperature is low, the viscosity of the side chain type polymer film in the liquid crystal state is high, and realignment due to self-organization becomes less likely to occur. For example, when the heating temperature is in the range of 10 ° C higher than the lower limit of the liquid crystal temperature range of the side chain type polymer film of the present invention, the heterogeneity due to heat in the side chain type polymer film can be obtained. The effect is increased, but the effect is still insufficient.

Further, the side chain type polymer film of the present invention exhibits a liquid crystal state by heating, but when the heating temperature is high, the state of the side chain type polymer film is close to the liquid state of the uniformity, and is self-organized in one direction. It is difficult to perform realignment. For example, when the heating temperature is higher than the temperature lower than the upper limit of the liquid crystal temperature range of the side chain type polymer film of the present invention, the heterogeneity caused by the heat in the side chain type polymer film can be obtained. The effect of the slap, but the effect is still insufficient.

When the heating temperature of the first heat treatment is higher than the temperature lower than the upper limit of the liquid crystal temperature range of the side chain type polymer film of the present invention, for example, 200 ° C or higher, the reaction temperature is higher than the reaction temperature of the siloxane. At the time of the reaction, the thermal reaction of the oxirane portion is sometimes carried out. At this time, the side chain type polymer film is self-organized, and it becomes difficult to realign in one direction. For example, when the heating temperature exceeds 200 ° C, the effect of the unevenness caused by the heat in the side chain type polymer film cannot be sufficient.

The method for producing the liquid crystal alignment film of the present invention is as described above. Since the introduction of the high-efficiency heterogeneity of the side chain type polymer film is achieved, the preferred heating temperature is determined based on the liquid crystal temperature range of the side chain type polymer film and the reaction temperature range of the oxirane portion. As described above, the heating temperature after the polarized ultraviolet ray irradiation is lower than the lower limit of the liquid crystal temperature range of the side chain type polymer film by 10 ° C, the temperature is lower than 200 ° C and lower than the upper limit of the liquid crystal temperature range by 10 ° C. The temperature within the range of the upper limit. Therefore, for example, when the liquid crystal temperature range of the side chain type polymer film of the present invention is in the range of 100 ° C to 200 ° C and the helium oxide portion is reacted at a higher temperature than 200 ° C, the heating temperature after the polarized ultraviolet light irradiation is preferably 110 to 190. °C. Thereby, a larger heterogeneity is imparted to the side chain type polymer film.

Next, each step of the method for producing a liquid crystal alignment film of the present invention will be more specifically described.

The method for producing a liquid crystal alignment film of the present invention has the following steps [1] to [IV] in the following order as described above. Thereby, the liquid crystal alignment film into which the non-uniformity is introduced can be efficiently produced.

[I]; a step of forming a side chain type polymer film exhibiting liquid crystallinity in a predetermined temperature range on the substrate, [II]; and irradiating the side chain type polymer film obtained in the step [I] with polarized light a step of ultraviolet rays after the step, [III]; a step of heating the side chain type polymer film after the polarized ultraviolet irradiation in step [II] and [IV]; and a side chain height after heating in the step [III] The molecular film is then reheated at a different temperature than step [III].

Hereinafter, a method for producing a liquid crystal alignment film of the present invention will be described. It has the steps of [I]~[IV].

The step [I] is to form a side chain type polymer film of the present invention on a substrate.

The substrate is not particularly limited. In addition to the glass substrate, a transparent substrate such as a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. In view of the simplification of the process of the liquid crystal display device, a substrate on which an ITO (Indium Tin Oxide) electrode for liquid crystal driving or the like is formed can be used in consideration of the use of the obtained liquid crystal alignment film. Further, in consideration of the use of a reflective liquid crystal display device, an opaque substrate such as a germanium wafer may be used. In this case, a material that reflects light such as aluminum may be used as the electrode.

When the side chain type polymer film of the present invention is dissolved in a solution of a desired solvent, the film formation on the substrate is carried out by applying the solution-like side chain type polymer film.

The coating method is not particularly limited, and industrially, it is generally applied by screen printing, lithography, flexographic printing, inkjet printing or the like. Other coating methods include, for example, a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray coating method, and the like, and such coating methods may be used depending on the purpose.

After coating the side chain type polymer film of the present invention in a solution form on a substrate, it is heated at 20 to 180 ° C, preferably 40 by a heating means such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven. The side chain type polymer film was obtained by evaporating the solvent at ~150 °C.

When the thickness of the side chain type polymer film is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element using the liquid crystal alignment film. When the thickness is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, it is preferably 5 to 300 nm. Better It is 10~100nm.

After the step [I], the step of cooling the substrate on which the side chain type polymer film is formed to room temperature may be provided before the step [II].

In the step [II], the polarized ultraviolet light is irradiated onto the side chain type polymer film obtained in the step [I], and the first alignment treatment is performed. When the film surface of the side chain type polymer film is irradiated with the polarized ultraviolet light, the polarized plate is shielded in a predetermined direction from the substrate, and the polarized ultraviolet light is irradiated.

Ultraviolet rays used in the range of 100 to 400 nm can be used. It is preferred to select an optimum wavelength depending on the type of the side chain type polymer film to be used, such as a filter. For example, selective initiation of photocrosslinking reaction may be carried out using ultraviolet light having a wavelength in the range of 290 to 400 nm. For ultraviolet rays, for example, light emitted from a high pressure mercury lamp can be used.

The irradiation amount of the polarized ultraviolet light is preferably in the range of 1 to 70%, more preferably 1 to 50%, of the amount of the polarized ultraviolet ray of ΔAmax of the side chain type polymer film of the present invention to be used. Within the scope.

In the step [III], the first heat treatment is performed by heating the side chain type polymer film irradiated with the polarized ultraviolet light in the step [II]. The heating treatment uses a heating means such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven.

The heating temperature is determined as described above in consideration of the temperature at which the liquid crystallinity of the side chain type polymer film of the present invention is exhibited. In other words, the heating temperature in this step is a temperature at which the side chain type polymer film is realigned.

The heating temperature of the step after the polarized ultraviolet irradiation of the step [II] is a liquid crystal temperature exhibiting liquid crystallinity than the side chain type polymer film of the present invention. The temperature at which the lower limit of the range is 10 ° C higher is the lower limit, and the temperature within the range of 200 ° C or lower and 10 ° C lower than the upper limit of the liquid crystal temperature range is preferable. The side chain type polymer film of the present invention can exhibit liquid crystallinity and a temperature range in which no thermal reaction occurs, and is preferably 60 ° C or more and 180 ° C or less.

In the step [IV], the second heat treatment is performed by heating the side chain type polymer film heated in the step [III] at a temperature different from the heating temperature in the step [III]. The step [III] is a temperature at which the side chain type polymer film of the present invention is in a liquid crystal state, and a temperature within a range in which the oxirane portion does not generate a thermal reaction is selected, and heat treatment (first heat treatment) is performed. Therefore, in this step, a heating temperature higher than the heating temperature of the step [III] is selected, and heat treatment (second heat treatment) is performed. The heating temperature in this step is a temperature at which the side chain type polymer film of the step [III] is fixed by realignment.

The heat treatment is the same as step [III]. A heating means such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven can be used.

The heating temperature is determined as described above in consideration of the reaction temperature of the oxoxane portion in the side chain type polymer film of the present invention. For example, the heating temperature in this step is preferably 200 ° C or higher. Moreover, it is preferable that the side chain type polymer film has a temperature of 300 ° C or less which is less likely to cause thermal deterioration, and particularly preferably a temperature of 250 ° C or less.

In the above method, the method for producing a liquid crystal alignment film of the present invention can achieve high efficiency and introduce non-uniformity into the side chain type polymer film.

Further, the liquid crystal alignment film of the present invention having high reliability can be produced with high efficiency.

[Examples]

The invention will be described in more detail below by way of examples, but the invention is not limited thereto.

The abbreviations and structures of the compounds and organic solvents used in the following Synthesis Examples, Examples and Comparative Examples are as follows.

(decane monomer)

TEOS: tetraethoxy decane

ACPS: 3-propenyloxypropyltrimethoxydecane

(methacrylate monomer)

(Organic solvents)

NMP: N-methyl-2-pyrrolidone

BCS: Butyl Cyrus

PGME: propylene glycol monomethyl ether

(polymerization initiator)

AIBN: azobisisobutyronitrile

<Molecular weight determination>

The number average molecular weight and the weight average molecular weight of the acrylic copolymer were determined by using a GPC apparatus (Shodex (registered trademark) column KF803L and KF804L) manufactured by JASCO Corporation, and the solvent was dissolved in tetrahydrofuran at a flow rate of 1 mL (ml)/min. The measurement was carried out under the conditions of flow through the column (column temperature 40 ° C). In addition, the following number average molecular weight (hereinafter referred to as Mn) and weight average molecular weight (hereinafter referred to as Mw) are expressed in terms of polystyrene.

<Synthesis of polyoxyalkylene>

<Synthesis Example 1>

Polyoxane (A): A 4-port reaction flask equipped with a reflux tube was charged with PGME (15.6 g), TEOS (18.8 g) and ACPS (2.3 g), and stirred at room temperature for 10 minutes. Next, a mixture of PGME (7.8 g), oxalic acid (0.1 g) and H ₂ O (5.4 g) was dropped into the solution. After dripping, it was heated to reflux for 3 hours and then allowed to cool to room temperature. After cooling, the polyaluminoxane (A) solution was diluted with PGME (50 g).

[Residual alkoxydecane monomer assay]

The residual alkoxydecane monomer in the solution of the prepared polyoxyalkylene (A) was measured using a gas chromatograph (hereinafter referred to as GC).

The GC measurement was performed using Shimadzu GC-14B manufactured by Shimadzu Corporation, using the following conditions.

Column: capillary column CBP1-W25-100 (length 25mm, diameter 0.53mm, thickness 1μm)

Column temperature: From a starting temperature of 50 ° C, a temperature rise of 15 ° C / min to a temperature of 290 ° C (holding time of 3 minutes).

Sample injection amount: 1 μL, injection temperature: 240 ° C, detector temperature: 290 ° C, carrier gas: nitrogen (flow rate: 30 mL/min), detection method: FID method.

As a result of the measurement, no alkoxydecane monomer was detected in the polyoxyalkylene (A) solution.

<Synthesis of Polysiloxane-Polymethacrylate Hybrid and Modulation of Liquid Crystal Alignment Treatment Agent>

<Synthesis Example 2>

1.0 g of polyadenine (A) obtained in Synthesis Example 1, M6CB 2 g (3.9 mmol), and AIBN 0.08 g (0.47 mmol) as a polymerization initiator were added to 20 ml of NMP, and the mixture was stirred at room temperature to dissolve all the solids. After the reaction system was replaced with nitrogen, the reaction temperature was gradually increased, and the reaction was carried out by stirring at 50 ° C for 15 hours (hours). After the completion of the reaction, the reaction solution was poured into 500 ml of diethyl ether to separate the polymer. After removing the AIBN, the precipitate was separated by filtration to obtain a polyoxyalkylene-polymethacrylic acid. Acid ester mixture (P6CBS) powder (B).

The P6CBS powder (B) was observed under a polarizing microscope while being heated, and it was found that liquid crystallinity was exhibited in a temperature range of 60 to 300 ° C or higher. Then, when P6CBS was further heated at 300 ° C, the decane was subjected to a condensation reaction, and P6CBS became a thermally cured product, and the liquid crystallinity gradually disappeared. The phase transfer behavior of this polyoxyalkylene-polymethacrylate mixture (P6CBS) is shown in Table 1.

<Synthesis Example 3>

2.5 g of polyadenine (A) obtained in Synthesis Example 1, M6CA2g (6.0 mmol), and AIBN 0.13 g (0.79 mmol) as a polymerization initiator were added to 22 ml of NMP, and the mixture was stirred at room temperature to dissolve all the solids. After the reaction system was replaced with nitrogen, the reaction temperature was gradually increased, and the reaction was carried out by stirring at 50 ° C for 15 hours (hours). After the completion of the reaction, the reaction solution was poured into 500 ml of diethyl ether to separate the polymer. After removing the AIBN, the precipitate was separated by filtration to obtain a polyoxoxane-polymethacrylate mixture (P6CAS) powder (C).

The P6CAS powder (C) was observed under a polarizing microscope while being heated, and it was found to exhibit liquid crystallinity at 80 to 190 °C. Then, when P6CAS is heated to 200 ° C or higher, the oxirane undergoes a condensation reaction, and P6CAS becomes a thermally cured product, and the liquid crystal property disappears. The phase shift behavior of this polyoxyalkylene-polymethacrylate mixture (P6CAS) is shown in Table 1.

<Example 1>

NMP and BCS were added to the polyoxane-polymethacrylate mixture (P6CBS) (powder (B)) obtained in Synthesis Example 2, and diluted to 4% by mass to obtain a liquid crystal alignment treatment agent (I). No abnormality such as turbidity or precipitation was observed in the liquid crystal alignment treatment agent, and it was confirmed that the resin component was uniformly dissolved. The liquid crystal alignment treatment agent was measured by GPC, and the molecular weight of P6CBS was measured, and the Mn was found to be 35,000.

[Determination of the content of decane in the mixture polymer]

The content of the decane in the polyoxyalkylene-polymethacrylate mixture (powder (B)) was calculated by GPC. The decane content is calculated by comparing the peak ratio of the methacrylate monomer of the GPC chart after radical polymerization with the peak ratio of the polyoxyalkylene-polymethacrylate mixture.

The ratio of the decane-methacrylate in the calculated P6CBS was expressed by a weight ratio of 1:5.

<Example 2>

Polyoxane-polymethacrylate mixture obtained in Synthesis Example 3 (P6CAS) (Powder (C)) was added with NMP and BCS, and diluted to 4% by mass to obtain a liquid crystal alignment treatment agent (II). No abnormality such as turbidity or precipitation was observed in the liquid crystal alignment treatment agent, and it was confirmed that the resin component was uniformly dissolved. The liquid crystal alignment treatment agent was measured by GPC, and the molecular weight of P6CAS was measured, and the Mn was found to be 48,000. Further, the ratio of the oxirane-methacrylate of P6CAS calculated by GPC was 2:3.5 by weight.

<Manufacture of liquid crystal alignment film>

<Example 3>

The liquid crystal alignment treatment agent (I) containing the polyoxyalkylene-polymethacrylate mixture (P6CBS) obtained in Example 1 was spin-coated on a quartz substrate (length 10 × width 10 × thickness 1 (mm)) After drying on a hot plate at 80 ° C for 5 minutes, a coating film having a film thickness of 50 nm was formed to obtain a substrate containing a liquid crystal alignment film before the alignment treatment.

<Example 4>

Using the substrate containing the liquid crystal alignment film before the alignment treatment obtained in Example 3, the polarized ultraviolet rays were irradiated to the liquid crystal alignment film surface on the substrate in a predetermined direction through the polarizing plate. The intensity of the polarized ultraviolet light was 14 mW at a wavelength of 365 nm, and the ultraviolet irradiation amount was 600 mJ. Then, the substrate irradiated with the ultraviolet ray was heated at 150 ° C for 5 minutes to form a liquid crystal state of the coating film P6CBS, and the coating film (polymer film) was subjected to realignment treatment to obtain a liquid crystal alignment film after the alignment treatment. The substrate. The obtained liquid crystal high film-containing substrate is used for measuring ultraviolet absorption spectrum as described later. (Figure 5).

<Example 5>

The substrate containing the liquid crystal alignment film before the alignment treatment obtained in Example 3 was used, and the polarized light was irradiated to the liquid crystal alignment film surface on the substrate in a predetermined direction through the polarizing plate. The intensity of the ultraviolet light after the polarized light was 14 mW at a wavelength of 365 nm, and the ultraviolet irradiation amount was 600 mJ. Then, the substrate irradiated with the ultraviolet ray was heated at 150 ° C for 5 minutes to form a liquid crystal state of the coating film P6CBS, and the coating film was subjected to realignment treatment. Next, the substrate subjected to the re-alignment treatment was heated to 200 ° C, and calcination was carried out at this temperature for 15 minutes to carry out a condensation reaction of the decane to fix the alignment. Thus, the substrate containing the liquid crystal alignment film after the alignment treatment was obtained.

<Example 6>

The substrate containing the liquid crystal alignment film before the alignment treatment obtained in Example 3 was used, and the polarized light was irradiated to the liquid crystal alignment film surface on the substrate in a predetermined direction through the polarizing plate. The intensity of the ultraviolet light after the polarized light was 14 mW at a wavelength of 365 nm, and the ultraviolet irradiation amount was 800 mJ. Then, the substrate irradiated with the ultraviolet ray was heated at 150 ° C for 5 minutes to form a liquid crystal state of the coating film P6CBS, and the coating film was subjected to realignment treatment to obtain a substrate containing the liquid crystal alignment film after the alignment treatment.

The obtained liquid crystal high-film-containing substrate was used to measure an ultraviolet absorption spectrum (FIG. 6) as will be described later.

<Example 7>

The substrate containing the liquid crystal alignment film before the alignment treatment obtained in Example 3 was used, and the polarized light was irradiated to the liquid crystal alignment film surface on the substrate in a predetermined direction through the polarizing plate. The intensity of the ultraviolet light after the polarized light was 14 mW at a wavelength of 365 nm, and the ultraviolet irradiation amount was 800 mJ. Then, the substrate after the ultraviolet irradiation was heated at 150 ° C for 5 minutes to form a liquid crystal state of the coating film P6CBS, and the coating film was subjected to a realignment treatment. Next, the substrate subjected to the re-alignment treatment was heated to 200 ° C, and calcination was carried out at this temperature for 15 minutes to carry out a condensation reaction of the decane to fix the alignment. Thus, the substrate containing the liquid crystal alignment film after the alignment treatment was obtained.

<Evaluation of liquid crystal alignment film>

<Example 8>

The ultraviolet absorption spectrum of the liquid crystal alignment film was measured using the substrate containing the liquid crystal alignment film obtained after the alignment treatment obtained in Example 4.

Fig. 5 is a graph showing the polarization electric field spectrum, parallel and perpendicular ultraviolet absorption spectrum of the ultraviolet ray after irradiation of the liquid crystal alignment film obtained in Example 4.

Fig. 5 is a view showing the ultraviolet absorption spectrum of the liquid crystal alignment film obtained in Example 4 (indicated by "parallel after heating" and "vertical after heating"), wherein the comparison object is only polarized ultraviolet irradiation (Example 4) The ultraviolet absorption spectrum of the liquid crystal alignment film before heat treatment (in the figure, "parallel after polarized light irradiation" and "vertical after polarized light irradiation").

As shown in FIG. 5, the ultraviolet absorption spectrum of Example 4 was compared with the ultraviolet absorption spectrum of the liquid crystal alignment film of Example 4 and the ultraviolet absorption spectrum of the substrate (only before the heat treatment of Example 4). The polarized electric field of the polarized ultraviolet light after the irradiation is the difference between the ultraviolet absorption spectrum of the parallel direction and the vertical direction, and is larger than the polarized electric field of the polarized ultraviolet light after the irradiation of the substrate (before the heat treatment of the fourth embodiment). The difference in the ultraviolet absorption spectrum between the parallel direction and the vertical direction revealed that the liquid crystal alignment film obtained in Example 4 was heated by polarized ultraviolet light irradiation to carry out realignment treatment.

Fig. 6 is a graph showing the parallel and vertical ultraviolet absorption spectra of the polarization electric field spectrum of the ultraviolet ray after the irradiation with the liquid crystal alignment film obtained in Example 6.

Fig. 6 is a view showing the ultraviolet absorption spectrum of the liquid crystal alignment film obtained in Example 6 (indicated by "parallel after heating" and "vertical after heating"), wherein the object of comparison is only the irradiation of polarized ultraviolet rays (heating of Example 6). The ultraviolet absorption spectrum of the liquid crystal alignment film before the treatment (in the figure, "parallel after polarized light irradiation" and "vertical after polarized light irradiation").

As shown in Fig. 6, the liquid crystal alignment film obtained in Example 6 was also heated in the same manner as in the liquid crystal alignment film obtained in Example 4, and the polarized electric field of the polarized ultraviolet light after irradiation was parallel. The difference between the ultraviolet absorption and the ultraviolet absorption in the vertical direction is larger than that of the polarized ultraviolet light alone (before the heat treatment of the fourth embodiment), and the polarized electric field of the polarized ultraviolet light after the irradiation is parallel and perpendicular. The difference in the ultraviolet absorption spectrum revealed that the liquid crystal alignment film obtained in Example 6 was heated by irradiation with polarized ultraviolet rays to carry out realignment treatment.

<Manufacture of liquid crystal cell>

<Example 9>

A liquid crystal alignment film was produced by using the liquid crystal alignment treatment agent (I) obtained in Example 1, and a liquid crystal cell using the liquid crystal alignment film was produced. The liquid crystal cell system corresponds to the characteristics of the liquid crystal alignment film, and serves as a liquid crystal cell in parallel alignment. The obtained liquid crystal cell is held by a pair of polarizing plates to form a liquid crystal display element.

In the method for producing a liquid crystal cell, for example, a liquid crystal alignment treatment agent (I) is spin-coated on a glass substrate containing an ITO electrode, and dried on a hot plate at 80° C. for 5 minutes to form a liquid crystal alignment film having a film thickness of 50 nm. A substrate containing a liquid crystal alignment film before the alignment treatment was obtained. It is understood that the liquid crystal alignment film formed on the substrate is excellent in uniformity of film thickness, and the liquid crystal alignment treatment agent (I) exhibits excellent coatability.

Using the obtained substrate containing the liquid crystal alignment film before the alignment treatment, the polarized light is irradiated to the liquid crystal alignment film surface on the substrate in a predetermined direction through the polarizing plate. The intensity of the ultraviolet light after the polarized light was 14 mW at a wavelength of 365 nm, and the ultraviolet irradiation amount was 600 mJ. Then, the substrate after the ultraviolet irradiation was heated at 150 ° C for 5 minutes to form a liquid crystal state of the coating film P6CBS, and the coating film was subjected to a realignment treatment. Next, the substrate subjected to the re-alignment treatment was heated to 250 ° C, and calcination was carried out at this temperature for 15 minutes to carry out a condensation reaction of the decane to fix the alignment. Thus, the substrate containing the liquid crystal alignment film after the alignment treatment was obtained.

Two sheets of the liquid crystal alignment film-containing substrate were prepared, and a 14 μm spacer was placed on the liquid crystal alignment film surface, and then a sealing agent was applied thereon. Next, after the other substrate is bonded to the liquid crystal alignment film, the sealant is hardened to form an empty cell. This empty cell was injected into a nematic liquid crystal (ZLI-4792 manufactured by Merck Co., Ltd.) at 105 ° C which is equal to or higher than the liquid phase temperature of the liquid crystal by a capillary phenomenon to obtain a liquid crystal cell.

<Example 10>

A liquid crystal cell was produced in the same manner as in Example 9 except that the amount of ultraviolet light irradiated by the polarized light was set to 800 mJ.

<Evaluation of Liquid Crystal Display Element>

<Example 11>

Using the liquid crystal cells obtained in Example 9 and Example 10, the alignment state of the liquid crystal was evaluated using a polarizing microscope. In other words, the liquid crystal cell was held by a pair of polarizing plates using a polarizing microscope to constitute a liquid crystal display element for evaluation. There was no alignment defect in any of the liquid crystal cells, and a good alignment state of the liquid crystal was observed. The evaluation results are shown in Table 2.

[Industrial Applicability]

The present invention provides a polymer and a liquid crystal alignment agent suitable for producing a liquid crystal alignment film using high efficiency of light, and the liquid crystal alignment film and liquid crystal display element obtained from the liquid crystal alignment agent are lightweight, thin, and can be used as low power consumption. The display device is used.

The present invention is incorporated by reference in its entirety to the specification of the disclosure of the disclosure of the disclosure of the entire disclosure of the disclosure of

1‧‧‧Side chain polymer film

2, 2a, 2b‧‧‧ side chain

Claims (6)

A polymer characterized in that a polysiloxane (a) having a radical polymerizable group and a monomer having a liquid crystal property and a photosensitive group and a radical polymerizable group (b) are subjected to radical polymerization. to make. The polymer of the first aspect of the invention, wherein the polyoxyalkylene (a) is a polyoxyalkylene obtained by polycondensing an alkoxysilane having an alkoxydecane of the following formula (10), R ¹³ _s1 Si(OR ¹⁴ ) _s2 (10) (In the formula (10), R ¹³ is an alkyl group substituted by an acryl fluorenyl group, a methacryl fluorenyl group, a styryl group or an aryl group, and R ¹⁴ represents hydrogen or carbon. A number of 1 to 5 alkyl groups, S1 is 1 or 2, and S2 is 2 or 3). The polymer of claim 1, wherein the liquid crystalline and photosensitive group of the monomer (b) is composed of azobenzene, diphenylethylene, cinnamic acid, cinnamic acid ester, chalcone, and fragrant. At least one selected group selected from the group consisting of soybean, diphenylacetylene, and benzoate. The polymer according to any one of claims 1 to 3, wherein the monomer (b) has an acrylate, a methacrylate, a maleimide, and an α-methylene-γ. - a polymerizable group consisting of at least one selected from the group consisting of butyrolactone and selected from the group consisting of the following formulas (1) to (5), (7), and (8) At least one of the side chain monomers, (In the formula (1), A ₁ and B ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-, Y ₁ system a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, which are bonded to each other independently of each other -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy, X ₁ represents a single bond, -COO-, -OCO-, - N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -, 11 represents an integer from 1 to 12, m1 represents an integer from 1 to 3, and n1 represents an integer from 1 to 12, In the formula (2), A ₂ , B ₂ and D ₁ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-, Y ₂ a group selected from a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a cyclic hydrocarbon having a carbon number of 5 to 8, or a combination thereof, which are bonded to each other independently of the hydrogen atom system. Substituted by -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy, X ₂ represents a single bond, -COO-, -OCO-, -N = N -, - CH = CH -, - C≡C- or C ₆ H ₄ -, R ₁ represents a hydrogen atom-based, or an alkyl group having 1 to 6 carbon atoms, the 12 Represents an integer of 1 to 12, m2 represents an integer of 1 to 3 lines of, n2 represents an integer of 1 to line 12, the formula (3), A ₃ represents a single bond _{lines, -O -, - CH 2 -} , - COO- , -OCO-, -CONH- or -NH-CO-, X ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -, R ₂ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, 13 represents an integer of 1 to 12, m3 represents an integer of 1 to 3, and in the formula (4), 14 represents 1 to 12 In the formula (5), A ₄ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-, and X ₄ represents -COO- Y ₃ is a group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a combination thereof, and the hydrogen atom bonded to each of them may be independently -NO ₂ , -CN, -CH=C ( CN) ₂ , -CH=CH-CN, halo, alkyl or alkoxy substituted, 15 represents an integer from 1 to 12, m4 represents an integer from 1 to 3, and in the formula (7), A ₅ represents Single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-, R ₃ -based hydrogen atom, -NO ₂ , -CN, -CH=C(CN) ₂ , -CH=CH-CN, a halogen group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or a group consisting of the combination thereof, 16 series representing an integer of 1 to 12, a bond End with Hydrogen line (7) in the phenyl ring independently may be _{-NO 2, -CN, -CH = C} (CN) 2, -CH = CH-CN, substituted with halo, alkyl or alkoxy, of formula In (8), A ₆ represents a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-, and B ₃ represents a single bond, -COO-, -OCO-, -N=N-, -CH=CH-, -C≡C- or C ₆ H ₄ -, W ₁ is a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a carbon number The cyclic hydrocarbons of 5 to 8 or the selected groups of the combinations of the hydrogen atoms bonded to each other may be independently -NO ₂ , -CN, -CH=C(CN) ₂ , -CH= CH-CN, halo, alkyl or alkoxy are substituted, 17 is an integer from 1 to 12, and m ₅ and m ₆ are each independently representing an integer from 1 to 3. The polymer according to any one of claims 1 to 3, wherein the amount of the monomer (b) used is 0.5 relative to the alkoxydecane 1 mol of the polysiloxane (a). ~50 m. A liquid crystal alignment agent characterized by containing the polymer of any one of claims 1 to 5.