JP6864251B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

The present invention relates to a novel liquid crystal alignment agent, a liquid crystal alignment film obtained from the novel liquid crystal alignment agent, and a liquid crystal display element having the same. The liquid crystal display element obtained by the present invention has excellent electrical characteristics.

Liquid crystal display elements are known as lightweight, thin, and low power consumption display devices, and have made remarkable progress in recent years, such as being used in large-scale television applications. The liquid crystal display element is configured by sandwiching the liquid crystal layer between, for example, a pair of transparent substrates provided with electrodes. Then, in the liquid crystal display element, an organic film made of an organic material is used as the liquid crystal alignment film so that the liquid crystal is in a desired orientation state between the substrates.

That is, the liquid crystal alignment film is a constituent member of the liquid crystal display element, is formed on the surface of the substrate that sandwiches the liquid crystal in contact with the liquid crystal, and plays a role of orienting the liquid crystal in a certain direction between the substrates. The liquid crystal alignment film may be required to have a role of controlling the pretilt angle of the liquid crystal in addition to the role of orienting the liquid crystal in a certain direction such as a direction parallel to the substrate. The ability to control the orientation of the liquid crystal in such a liquid crystal alignment film (hereinafter referred to as the orientation control ability) is given by performing an orientation treatment on the organic film constituting the liquid crystal alignment film.

A rubbing method has been conventionally known as an orientation treatment method for a liquid crystal alignment film for imparting an orientation control ability. The rubbing method is to rub the surface of an organic film such as polyvinyl alcohol, polyamide, or polyimide on a substrate with a cloth such as cotton, nylon, or polyester in a certain direction (rubbing) in a rubbing direction (rubbing direction). This is a method of orienting a liquid crystal. Since this rubbing method can easily realize a relatively stable orientation state of a liquid crystal, it has been used in a conventional manufacturing process of a liquid crystal display element. As the organic film used for the liquid crystal alignment film, a polyimide-based organic film having excellent reliability such as heat resistance and electrical characteristics has been mainly selected.

However, the rubbing method of rubbing the surface of a liquid crystal alignment film made of polyimide or the like may cause problems such as dust generation and generation of static electricity. In addition, due to the recent high definition of liquid crystal surface elements and the unevenness of the corresponding electrodes on the substrate and switching active elements for driving the liquid crystal, the surface of the liquid crystal alignment film cannot be rubbed uniformly with a cloth, and is uniform. Sometimes the orientation of the liquid crystal could not be achieved.

Therefore, the photo-alignment method has been actively studied as another alignment treatment method for the liquid crystal alignment film without rubbing.

There are various photo-alignment methods, but anisotropy is formed in the organic film constituting the liquid crystal alignment film by linearly polarized light or collimated light, and the liquid crystal is oriented according to the anisotropy.

As the main photo-orientation method, a decomposition type photo-orientation method is known. In this method, for example, the polyimide film is irradiated with polarized ultraviolet rays, and anisotropic decomposition is caused by utilizing the polarization direction dependence of the ultraviolet absorption of the molecular structure. Then, the liquid crystal is oriented by the polyimide left without decomposition (see, for example, Patent Document 1).

Further, as another photo-orientation method, a photocrosslinking type or a photoisomerization type photo-alignment method is also known. In the photocrosslinking type photoalignment method, for example, polyvinyl synnamate is used to irradiate polarized ultraviolet rays to cause a dimerization reaction (crosslinking reaction) at a double bond portion of two side chains parallel to polarized light. Then, the liquid crystal is oriented in a direction orthogonal to the polarization direction (see, for example, Non-Patent Document 1). In the photoisomerization type photoorientation method, when a side chain type polymer having azobenzene in the side chain is used, polarized ultraviolet rays are irradiated to cause an isomerization reaction in the azobenzene part of the side chain parallel to polarized light, resulting in polarization. The liquid crystal is oriented in a direction orthogonal to the direction (see, for example, Non-Patent Document 2).

As described in the above example, the method of aligning the liquid crystal alignment film by the photo-alignment method does not require rubbing, and there is no concern about dust generation or static electricity generation. Then, the orientation treatment can be applied to the substrate of the liquid crystal display element having an uneven surface, which is a method of orientation treatment of the liquid crystal alignment film suitable for an industrial production process.

Japanese Patent No. 3893659

M. Shatt et al. , Jpn. J. Applied Phys. 31,155 (1992) K. Ichimura et al. , Chem. Rev. 100,1847 (2000)

As described above, the photo-alignment method has a great advantage because it does not require the rubbing step itself as compared with the rubbing method which has been industrially used conventionally as a method for aligning a liquid crystal display element. Then, as compared with the rubbing method in which the orientation control ability is substantially constant by rubbing, in the photoalignment method, the orientation control ability can be controlled by changing the irradiation amount of polarized light. However, in the photo-alignment method, when trying to achieve the same degree of orientation control ability as in the rubbing method, a large amount of polarized light irradiation may be required, and stable liquid crystal orientation cannot be realized. There is.

For example, in the decomposition type photoalignment method described in Patent Document 1 described above, it is necessary to irradiate the polyimide film with ultraviolet light from a high-pressure mercury lamp having an output of 500 W for 60 minutes, which requires a long period of time and a large amount of ultraviolet irradiation. Become. Further, even in the case of the dimerization type or photoisomerization type photoalignment method, it may be necessary to irradiate a large amount of ultraviolet rays of about several J (joules) to several tens of J.

Therefore, in the photo-alignment method, high efficiency of orientation processing and realization of stable liquid crystal alignment are required, and a liquid crystal alignment film or liquid crystal capable of imparting high orientation control ability to the liquid crystal alignment film with high efficiency. Aligners are required.

An object of the present invention is to provide a liquid crystal alignment film for a liquid crystal display element, which is provided with high efficiency and orientation control ability and has excellent electrical characteristics, and a liquid crystal display element. Another object of the present invention is to provide a liquid crystal alignment agent that provides a liquid crystal alignment film having an improved voltage retention rate.

As a result of diligent studies to achieve the above problems, the present inventors have found the following inventions.
<1> [I] (A) A photosensitive side-chain polymer that exhibits liquid crystallinity in a predetermined temperature range.
A polymer composition containing (B) a heteropolyacid and (C) an organic solvent.

<2> In the above <1>, the component (A) preferably has a photosensitive side chain that causes photocrosslinking, photoisomerization, or photofries rearrangement.
<3> In the above <1> or <2>, the heteropolyacid is preferably phosphotungstic acid.
<4> In any of the above <1> to <3>, the component (A) preferably further has a side chain represented by the following formula (0).

In the formula, A and B are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO-O-. , Or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When CH-represents and the number of Xs is 2, the Xs may be the same or different;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bound is an aromatic ring;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond;
G is the following formula (G-1), (G-2), (G-3) and (G-4).

(In the formula, the broken line represents the bond, R ⁵⁰ represents a group selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, and a phenyl group. When ^{there are a plurality of R 50s,} they are the same or different from each other. T is an integer of 1 to 7, J represents O, S, NH or NR ⁵¹ , and R ⁵¹ represents a group selected from alkyl and phenyl groups having 1 to 3 carbon atoms). Is the basis for this.
<5> In any of the above <1> to <4>, it is preferable that the component (A) further has a side chain (b-2) having a group selected from a pyridyl group, an amide group and a urethane group.
<6> In any of the above <1> to <5>, the component (A) has any one photosensitive side chain selected from the group consisting of the following formulas (1) to (6). Good.

In the formula, A, B, and D are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO-. Represents O- or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
Y ₁ represents a ring selected from a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring and an alicyclic hydrocarbon having 5 to 8 carbon atoms, or the same or selected from their substituents. It is a group consisting of 2 to 6 different rings bonded via a bonding group B, and the hydrogen atoms bonded to them are independently −COOR ₀ (in the formula, R ₀ is a hydrogen atom or 1 to 1 carbon atoms). (Representing an alkyl group of 5), -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms. May be substituted with an alkyloxy group;
Y ₂ is a group selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. The hydrogen atoms bonded to are independently -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, halogen group, alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. May be substituted with an alkyloxy group of;
R is hydroxy group, or an alkoxy group having 1 to 6 carbon atoms, or represents the same definition as Y _1;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When CH-represents and the number of Xs is 2, the Xs may be the same or different;
Cou represents a coumarin-6-yl group or a coumarin-7-yl group, and the hydrogen atoms bonded to them are independently -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-. It may be substituted with CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;
One of q1 and q2 is 1 and the other is 0;
q3 is 0 or 1;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bonded is an aromatic ring. When the number of Ps is 2 or more, the Ps may be the same or different, and when the number of Qs is 2 or more, the Qs may be the same or different;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond;
H and I are groups independently selected from a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, and a combination thereof.

<7> In any of the above <1> to <6>, the component (A) has any one liquid crystal side chain selected from the group consisting of the following formulas (21) to (31). Good.
In the formula, A and B have the same definition as above;
Y ₃ is a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and alicyclic hydrocarbons having 5 to 8 carbon atoms, and, with a group selected from the group consisting of Yes, the hydrogen atoms attached to them may be independently _{substituted with -NO 2} , -CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;
R ₃ contains hydrogen atom, -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, halogen group, monovalent benzene ring, naphthalene ring, biphenyl ring, furan ring, and nitrogen. Represents a heterocycle, an alicyclic hydrocarbon having 5 to 8 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms;
One of q1 and q2 is 1 and the other is 0;
l represents an integer of 1 to 12, m represents an integer of 0 to 2, but in equations (23) to (24), the sum of all m is 2 or more, and equations (25) to (26). ), The sum of all m is 1 or more, and m1, m2, and m3 independently represent integers 1 to 3;
R ₂ is a hydrogen atom, -NO ₂ , -CN, a halogen group, a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and an alicyclic hydrocarbon having 5 to 8 carbon atoms. And represents an alkyl group or an alkyloxy group;
Z ₁ and Z ₂ represent a single bond, -CO-, -CH ₂ O-, -CH = N-, -CF _2- .

<8> A step of applying the polymer composition according to any one of <1> to <7> above onto a substrate having a conductive film for driving a transverse electric field to form a coating film;
[II] A step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and a step of heating the coating film obtained in [III] [II];
A method for manufacturing a substrate having the liquid crystal alignment film, which obtains a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element to which an orientation control ability is imparted.
<9> A substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element manufactured by the above <8>.
<10> A transverse electric field driven liquid crystal display element having the substrate of <9> above.
<11> Step of preparing the substrate (first substrate) of <9>above;
[I'] A step of applying the polymer composition according to any one of <1> to <7> above on a second substrate to form a coating film;
[II'] A step of irradiating the coating film obtained in [I'] with polarized ultraviolet rays; and a step of heating the coating film obtained in [III'] [II'];
A step of obtaining a second substrate having the liquid crystal alignment film, which obtains a liquid crystal alignment film to which the orientation control ability is imparted by having the liquid crystal alignment film; and [IV] the liquid crystal alignment film of the first and second substrates via the liquid crystal. A step of obtaining a liquid crystal display element by arranging the first and second substrates so as to face each other;
A method for manufacturing a liquid crystal display element, which obtains a transverse electric field drive type liquid crystal display element.
<12> The transverse electric field drive type liquid crystal display element manufactured by the above <11>.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a liquid crystal alignment film for a liquid crystal display element and a liquid crystal display element, which are provided with high efficiency and orientation control ability and have excellent electrical characteristics.
Further, in the present invention, by incorporating the heteropolymetalate which is the component (B) in the polymer composition, a transverse electric field driven liquid crystal element having an excellent voltage retention even by low-temperature firing and the liquid crystal orientation for the element. A membrane can be provided.

As a result of diligent research, the present inventor has obtained the following findings and has completed the present invention.
The polymer composition used in the production method of the present invention has a photosensitive side-chain polymer capable of exhibiting liquid crystallinity (hereinafter, also simply referred to as a side-chain polymer), and the polymer composition. The coating film obtained by using the material is a film having a photosensitive side chain polymer capable of exhibiting liquid crystallinity. This coating film is subjected to an orientation treatment by polarization irradiation without performing a rubbing treatment. Then, after the polarization irradiation, the side chain type polymer film is heated to obtain a coating film having an orientation control ability (hereinafter, also referred to as a liquid crystal alignment film). At this time, the slight anisotropy developed by the polarization irradiation becomes the driving force, and the liquid crystal side chain polymer itself is efficiently reoriented by self-assembly. As a result, highly efficient alignment processing can be realized as a liquid crystal alignment film, and a liquid crystal alignment film with high orientation control ability can be obtained.

Further, in the polymer composition of the present invention, a heteropolyacid is used as the component (B) in addition to the side chain polymer which is the component (A) and the organic solvent which is the component (C). It was unexpected that this significantly improved the voltage retention rate. In addition to the fact that these phenomena are caused by the addition of the component (B), the present inventors have made a leap in the desired effect by demonstrating the interaction between the component (A) and the component (B). (Note that these include the inventor's view on the mechanism of the present invention and do not bind the present invention).
Hereinafter, embodiments of the present invention will be described in detail.

<Polymer composition>
The polymer composition of the present invention is (A) a photosensitive side chain polymer that exhibits liquid crystallinity in a predetermined temperature range.
It contains (B) a heteropolyacid and (C) an organic solvent.

<< (A) Side chain polymer >>
The component (A) is a photosensitive side chain polymer that exhibits liquid crystallinity in a predetermined temperature range.
The side chain polymer (A) preferably reacts with light in the wavelength range of 250 nm to 400 nm and exhibits liquid crystallinity in the temperature range of 100 ° C. to 300 ° C.
The side chain polymer (A) preferably has a photosensitive side chain that reacts with light in the wavelength range of 250 nm to 400 nm.
The side chain type polymer (A) preferably has a mesogen group because it exhibits liquid crystallinity in a temperature range of 100 ° C. to 300 ° C.

In the side chain type polymer (A), a side chain having photosensitivity is bonded to the main chain, and a cross-linking reaction, an isomerization reaction, or a photo Fries rearrangement can occur in response to light. The structure of the side chain having photosensitivity is not particularly limited, but a structure that causes a cross-linking reaction or a photo-Fries rearrangement in response to light is desirable, and one that causes a cross-linking reaction is more desirable. In this case, even if it is exposed to external stress such as heat, the realized orientation control ability can be stably maintained for a long period of time. The structure of the photosensitive side chain polymer capable of exhibiting liquid crystallinity is not particularly limited as long as it satisfies such characteristics, but it is preferable that the side chain structure has a rigid mesogen component. In this case, stable liquid crystal orientation can be obtained when the side chain polymer is used as a liquid crystal alignment film.

The structure of the polymer has, for example, a main chain and a side chain bonded thereto, and the side chain contains a mesogen component such as a biphenyl group, a terphenyl group, a phenylcyclohexyl group, a phenylbenzoate group, and an azobenzene group, and a tip thereof. It has a structure having a photosensitive group bonded to a portion and undergoing a cross-linking reaction or an isomerization reaction in response to light, a main chain and a side chain bonded to the main chain, and the side chain also serves as a mesogen component. It can have a structure having a phenylbenzoate group that undergoes a photofreeze rearrangement reaction.

More specific examples of the structure of a photosensitive side chain polymer capable of exhibiting liquidity include hydrocarbons, (meth) acrylates, itaconates, fumarates, maleates, α-methylene-γ-butyrolactone, styrene, and vinyl. , Maleimide, Norbornene and other radically polymerizable groups and a structure having a main chain composed of at least one selected from the group consisting of siloxane and a side chain composed of at least one of the following formulas (1) to (6). Is preferable.

In the formula, A, B, and D are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO-. Represents O- or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
Y ₁ represents a ring selected from a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring and an alicyclic hydrocarbon having 5 to 8 carbon atoms, or the same or selected from their substituents. It is a group consisting of 2 to 6 different rings bonded via a bonding group B, and the hydrogen atoms bonded to them are independently −COOR ₀ (in the formula, R ₀ is a hydrogen atom or 1 to 1 carbon atoms). (Representing an alkyl group of 5), -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms. May be substituted with an alkyloxy group;
Y ₂ is a group selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. The hydrogen atoms bonded to are independently -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, halogen group, alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. May be substituted with an alkyloxy group of;
R is hydroxy group, or an alkoxy group having 1 to 6 carbon atoms, or represents the same definition as Y _1;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When CH-represents and the number of Xs is 2, the Xs may be the same or different;
Cou represents a coumarin-6-yl group or a coumarin-7-yl group, and the hydrogen atoms bonded to them are independently -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-. It may be substituted with CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;
One of q1 and q2 is 1 and the other is 0;
q3 is 0 or 1;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bonded is an aromatic ring. When the number of Ps is 2 or more, the Ps may be the same or different, and when the number of Qs is 2 or more, the Qs may be the same or different;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond;
H and I are groups independently selected from a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, and a combination thereof.

The side chain is preferably any one of the photosensitive side chains selected from the group consisting of the following formulas (7) to (10).
In the formula, A, B, D, Y ₁ , X, Y ₂ , and R have the same definition as above;
l represents an integer from 1 to 12;
m represents an integer of 0 to 2, and m1 and m2 represent an integer of 1 to 3;
n represents an integer from 0 to 12 (where B is a single bond when n = 0).

The side chain is preferably any one of the photosensitive side chains selected from the group consisting of the following formulas (11) to (13).
In the formula, A, X, l, m, m1 and R have the same definitions as above.

The side chain is preferably a photosensitive side chain represented by the following formula (14) or (15).
In the formula, A, Y ₁ , l, m1 and m2 have the same definitions as above.

The side chain is preferably a photosensitive side chain represented by the following formula (16) or (17).
In the formula, A, X, l and m have the same definitions as above.

The side chain is preferably a photosensitive side chain represented by the following formula (18) or (19).
In the formula, A, B, Y1, q1, q2, m1 and m2 have the same definitions as above.
R ₁ is a hydrogen atom, -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyl having 1 to 5 carbon atoms. Represents an oxy group.

The side chain is preferably a photosensitive side chain represented by the following formula (20).
In the formula, A, Y ₁ , X, l and m have the same definitions as above.

Further, the side chain type polymer (A) preferably has any one liquid crystal side chain selected from the group consisting of the following formulas (21) to (31).
In the formula, A, B, q1 and q2 have the same definitions as above;
Y ₃ is a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and alicyclic hydrocarbons having 5 to 8 carbon atoms, and, with a group selected from the group consisting of Yes, the hydrogen atoms attached to them may be independently _{substituted with -NO 2} , -CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;
R ₃ contains hydrogen atom, -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, halogen group, monovalent benzene ring, naphthalene ring, biphenyl ring, furan ring, and nitrogen. Represents a heterocycle, an alicyclic hydrocarbon having 5 to 8 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms;
l represents an integer of 1 to 12, m represents an integer of 0 to 2, but in equations (23) to (24), the sum of all m is 2 or more, and equations (25) to (26). ), The sum of all m is 1 or more, and m1, m2, and m3 independently represent integers 1 to 3;
R ₂ is a hydrogen atom, -NO ₂ , -CN, a halogen group, a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and an alicyclic hydrocarbon having 5 to 8 carbon atoms. And represents an alkyl group or an alkyloxy group;
Z ₁ and Z ₂ represent a single bond, -CO-, -CH ₂ O-, -CH = N-, -CF _2- .

[Photoreactive side chain monomer]
The photoreactive side chain monomer is a monomer capable of forming a polymer having a photosensitive side chain at a side chain portion of the polymer when the polymer is formed.
As the photoreactive group of the side chain, the following structure and its derivative are preferable.

More specific examples of photoreactive side chain monomers include radically polymerizable groups such as hydrocarbons, (meth) acrylates, itaconates, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene. And a polymerizable side chain composed of at least one selected from the group consisting of siloxane and a photosensitive side chain composed of at least one of the above formulas (1) to (6), preferably, for example, the above formula (7). ) To (10), a photosensitive side chain consisting of at least one of the above formulas (11) to (13), and a photosensitive side chain consisting of at least one of the above formulas (14) or (15). The sex side chain, the photosensitive side chain represented by the above formula (16) or (17), the photosensitive side chain represented by the above formula (18) or (19), and the photosensitive side chain represented by the above formula (20). A structure having a sex side chain is preferable.

[Liquid crystal side chain monomer]
The liquid crystal side chain monomer is a monomer in which a polymer derived from the monomer exhibits liquid crystallinity and the polymer can form a mesogen group at a side chain site.
As the mesogen group of the side chain, even if it is a group having a mesogen structure by itself such as biphenyl or phenylbenzoate, or a group having a mesogen structure by hydrogen bonding between side chains such as benzoic acid. Good. The following structure is preferable as the mesogen group contained in the side chain.

More specific examples of liquid side chain monomers include hydrocarbons, (meth) acrylates, itaconates, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene and other radically polymerizable groups. It is preferable that the structure has a polymerizable group composed of at least one selected from the group consisting of siloxane and a side chain composed of at least one of the above formulas (21) to (31).

The content of the photoreactive side chain in the side chain polymer which is the component (A) of the present invention is preferably 10 mol% to 100 mol%, preferably 15 mol% to 95 mol% from the viewpoint of liquid crystal orientation. More preferably, 20 mol% to 80 mol% is further preferable.

The content of the liquid crystal side chain in the side chain polymer which is the component (A) of the present invention is preferably 0 to 90 mol%, more preferably 5 mol% to 85 mol% or less from the viewpoint of liquid crystal orientation. , 20 mol% to 80 mol% or less is more preferable.
<Specific copolymerization unit>
The polymer which is the component (A) in the present invention can contain a specific copolymer for the purpose of further improving the properties. Examples of the specific copolymerization unit include a side chain represented by the following formula (0) and a side chain (b-2) described below.

[Side chain represented by equation (0)]
The side chain represented by the formula (0) is as follows.

In the formula, A and B are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO-O-. , Or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When CH-represents and the number of Xs is 2, the Xs may be the same or different;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bound is an aromatic ring;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond;
G is the following formula (G-1), (G-2), (G-3) and (G-4).

(In the formula, the broken line represents the bond, R ⁵⁰ represents a group selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, and a phenyl group. When ^{there are a plurality of R 50s,} they are the same or different from each other. T is an integer of 1 to 7, J represents O, S, NH or NR ⁵¹ , and R ⁵¹ represents a group selected from alkyl and phenyl groups having 1 to 3 carbon atoms). Is the basis for this.

More specific examples of the monomer having a side chain represented by the formula (0) include hydrocarbons, (meth) acrylates, itaconates, fumarates, maleates, α-methylene-γ-butyrolactone, styrene, vinyl, and maleimides. , Norbornen and the like, preferably having a polymerizable group composed of at least one selected from the group consisting of a radically polymerizable group and siloxane, and a side chain represented by the above formula (0).

Among such monomers, specific examples of the monomer having an epoxy group include compounds such as glycidyl (meth) acrylate, (3,4-epoxycyclohexyl) methyl (meth) acrylate, and allyl glycidyl ether. Among them, glycidyl (meth) acrylate, (3,4-epoxycyclohexyl) methyl (meth) acrylate, 3-ethenyl-7-oxabicyclo [4.1.0] heptane, 1,2-epoxy-5- Examples include hexene, 1,7-octadienmonoepoxide, and the like.

Specific examples of the monomer having thiirane include those in which the epoxy structure of the above-mentioned monomer having an epoxy group is replaced with thiirane.
Specific examples of the monomer having aziridine include those in which the epoxy structure of the monomer having an epoxy group is replaced with aziridine or 1-methylaziridine.

Examples of the monomer having an oxetane group include a (meth) acrylic acid ester having an oxetane group. Among such monomers, 3- (methacryloyloxymethyl) oxetane, 3- (acryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) -3-ethyl-oxetane, 3- (acryloyloxymethyl) -3- Ethyl-oxetan, 3- (methacryloyloxymethyl) -2-trifluoromethyloxetane, 3- (acryloyloxymethyl) -2-trifluoromethyloxetane, 3- (methacryloyloxymethyl) -2-phenyl-oxetan, 3- (Acryloyloxymethyl) -2-phenyl-oxetan, 2- (methacryloyloxymethyl) oxetane, 2- (acryloyloxymethyl) oxetane, 2- (methacryloyloxymethyl) -4-trifluoromethyloxetane, 2- (acryloyloxymethyl) Methyl) -4-trifluoromethyloxetane is preferable, and examples thereof include 3- (methacryloyloxymethyl) -3-ethyl-oxetane and 3- (acryloyloxymethyl) -3-ethyl-oxetane.

As the monomer having a thietan group, for example, a monomer in which the oxetane group of the monomer having an oxetane group is replaced with the thietan group is preferable.

As the monomer having an azetan group, for example, a monomer in which the oxetane group of the monomer having an oxetane group is replaced with the azetan group is preferable.

Among the above, a monomer having an epoxy group and a monomer having an oxetane group are preferable, and a monomer having an epoxy group is more preferable, from the viewpoint of availability and the like. Of these, glycidyl (meth) acrylate is preferable from the viewpoint of availability.

[Side chain (b-2)]
The side chain (b-2) is a side chain having a group selected from a pyridyl group, an amide group and a urethane group. By containing such a side chain (b-2), when a liquid crystal alignment film is formed, the elution of ionic impurities is reduced and the cross-linking reaction of the group represented by the above formula (0) is promoted. Alternatively, a more durable liquid crystal alignment film can be obtained. In order to produce a polymer having a side chain (b-2), a monomer having a side chain (b-2) may be copolymerized.

Examples of the monomer having such a side chain (b-2) include hydrocarbons, (meth) acrylates, itaconates, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene and other radically polymerizable groups. A structure having a polymerizable group composed of at least one selected from the group consisting of siloxane and a side chain having a pyridyl group, an amide group and a urethane group is preferable. The NH of the amide group and the urethane group may or may not be substituted. Examples of the substituent which may be substituted include an alkyl group, an amino protecting group, a benzyl group and the like.

Among such monomers, specific examples of the monomer having a pyridyl group include 2- (2-pyridylcarbonyloxy) ethyl (meth) acrylate and 2- (3-pyridylcarbonyloxy) ethyl (meth) acrylate. , 2- (4-Pyridylcarbonyloxy) ethyl (meth) acrylate, and the like.

Specific examples of the monomer having an amide group or a urethane group include 2- (4-methylpiperidin-1-ylcarbonylamino) ethyl (meth) acrylate and 4- (6-methacryloyloxyhexyloxy) benzoic acid. Examples thereof include N- (terrary butyloxycarbonyl) piperidine-4-yl ester, 4- (6-methacryloyloxyhexyloxy) benzoic acid 2- (terrific butyloxycarbonylamino) ethyl ester and the like.

<< Polymer manufacturing method >>
The photosensitive side chain polymer capable of expressing the liquid crystal property of the above component (A) can be obtained by polymerizing a photoreactive side chain monomer having the above photosensitive side chain and a liquid crystal side chain monomer. Can be done.

The side chain type polymer (A) can be obtained by the polymerization reaction of the photoreactive side chain monomer exhibiting the liquid crystal property described above. Further, it can be obtained by copolymerizing a photoreactive side chain monomer that does not exhibit liquidity and a liquid crystal side chain monomer, or by copolymerizing a photoreactive side chain monomer that exhibits liquidity and a liquid crystal side chain monomer. it can. Further, it can be copolymerized with the monomer giving the side chain (0) or the monomer giving the side chain (b-2).

Further, the component (A) can be copolymerized with other monomers as long as the characteristics are not impaired.
Examples of other monomers include industrially available radical polymerization-reactive monomers.
Specific examples of other monomers include unsaturated carboxylic acids, acrylic acid ester compounds, methacrylic acid ester compounds, maleimide compounds, acrylonitrile, maleic acid anhydrides, styrene compounds and vinyl compounds.

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like.
Examples of the acrylic acid ester compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, and tert-butyl. Acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2- Examples thereof include propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, and 8-ethyl-8-tricyclodecyl acrylate.

Examples of the methacrylic acid ester compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate and tert-butyl. Methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2- Examples thereof include propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-tricyclodecyl methacrylate and the like. (Meta) acrylate compounds having a cyclic ether group such as glycidyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, and (3-ethyl-3-oxetanyl) methyl (meth) acrylate are also used. be able to.

Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, propyl vinyl ether and the like.
Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, bromostyrene and the like.
Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide and the like.

The method for producing the side chain polymer of the present embodiment is not particularly limited, and a general-purpose method that is industrially handled can be used. Specifically, it can be produced by cationic polymerization, radical polymerization, or anionic polymerization using a vinyl group of a liquid crystal side chain monomer or a photoreactive side chain monomer. Of these, radical polymerization is particularly preferable from the viewpoint of ease of reaction control.

As the polymerization initiator for radical polymerization, known compounds such as a radical polymerization initiator and a reversible addition-cleavage chain transfer (RAFT) polymerization reagent can be used.

The radical thermal polymerization initiator is a compound that generates radicals by heating to a temperature higher than the decomposition temperature. Examples of such radical thermal polymerization initiators include ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), and hydroperoxides (peroxidation). Hydrogen, tert-butylhydroxide, cumenehydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals (dibutylperoxycyclohexane, etc.) Etc.), alkyl peresters (peroxyneodecanic acid-tert-butyl ester, peroxypivalic acid-tert-butyl ester, peroxy2-ethylcyclohexanoic acid-tert-amyl ester, etc.), persulfates (potassium persulfate, etc.) Examples thereof include sodium persulfate, ammonium persulfate, etc.) and azo radical compounds (azobisisobutyronitrile, and 2,2'-di (2-hydroxyethyl) azobisisobutyronitrile, etc.). Such a radical thermal polymerization initiator may be used alone or in combination of two or more.

The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by light irradiation. Examples of such radical photopolymerization initiators include benzophenone, Michler's ketone, 4,4'-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone and 2-hydroxy. -2-Methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenylketone, isopropylbenzoin ether, isobutylbenzoin ether, 2,2-diethoxyacetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, camphorquinone, benzanthron, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-( 4-Molholinophenyl) -butanone-1, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4,4'-tri ( t-Butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2- (4'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3' , 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2 -(2'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4'-pentyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 4- [P-N, N-di (ethoxycarbonylmethyl)]-2,6-di (trichloromethyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (2'-chlorophenyl) -s- Triazine, 1,3-bis (trichloromethyl) -5- (4'-methoxyphenyl) -s-triazine, 2- (p-dimethylaminostyryl) benzoxazole, 2- (p-dimethylaminostyryl) benzthiazole, 2-Mercaptobenzothiazole, 3,3'-carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2 , 2'-bi Su (2-chlorophenyl) -4,4', 5,5'-tetrakis (4-ethoxycarbonylphenyl) -1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4, 4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'bis (2,4-dibromophenyl) -4,4', 5,5'-tetraphenyl-1,2' -Bimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-bimidazole, 3- (2-methyl-2) -Dimethylaminopropionyl) carbazole, 3,6-bis (2-methyl-2-morpholinopropionyl) -9-n-dodecylcarbazole, 1-hydroxycyclohexylphenylketone, bis (5-2,4-cyclopentadiene-1- Il) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3'-di (methoxycarbonyl) -4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4'-di (3,4'-di ( Methoxycarbonyl) -4,3'-di (t-butylperoxycarbonyl) benzophenone, 4,4'-di (methoxycarbonyl) -3,3'-di (t-butylperoxycarbonyl) benzophenone, 2- (3- (3-) Methyl-3H-benzothiazole-2-ylidene) -1-naphthalen-2-yl-etanone, or 2- (3-methyl-1,3-benzothiazole-2 (3H) -iriden) -1- (2-) Benzoyl) Etanone and the like can be mentioned. These compounds may be used alone or in admixture of two or more.

The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a massive polymerization method, a solution polymerization method and the like can be used.

The organic solvent used in the polymerization reaction of the photosensitive side chain polymer capable of exhibiting liquid crystallinity is not particularly limited as long as the produced polymer dissolves. Specific examples are given below.

N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide , Γ-Butylollactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethylamyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cell solve, ethyl cell solve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl Ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene Glycol monoacetate Monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether , Diisobutylketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, acetic acid Ethyl, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion Acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglime, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3- Examples thereof include ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like.

These organic solvents may be used alone or in combination. Further, even if the solvent does not dissolve the produced polymer, it may be mixed with the above-mentioned organic solvent and used as long as the produced polymer does not precipitate.
Further, in radical polymerization, oxygen in an organic solvent causes an inhibition of the polymerization reaction, so it is preferable to use an organic solvent that has been degassed to the extent possible.

The polymerization temperature at the time of radical polymerization can be selected from any temperature of 30 ° C. to 150 ° C., but is preferably in the range of 50 ° C. to 100 ° C. The reaction can be carried out at any concentration, but if the concentration is too low, it becomes difficult to obtain a polymer having a high mass, and if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the monomer concentration is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass. The initial reaction can be carried out at a high concentration and then an organic solvent can be added.

In the above-mentioned radical polymerization reaction, when the ratio of the radical polymerization initiator is large with respect to the monomer, the molecular weight of the obtained polymer is small, and when the ratio is small, the molecular weight of the obtained polymer is large. It is preferably 0.1 mol% to 10 mol% with respect to the monomer to be polymerized. Further, various monomer components, solvents, initiators and the like can be added at the time of polymerization.

[Recovery of polymer]
When recovering the produced polymer from the reaction solution of the photosensitive side chain polymer capable of expressing liquidity obtained by the above reaction, the reaction solution is put into a poor solvent and their weights are increased. The coalescence may be precipitated. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellsolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, water and the like. The polymer which has been put into a poor solvent and precipitated can be collected by filtration and then dried at normal temperature or by heating under normal pressure or reduced pressure. Further, by re-dissolving the polymer recovered by precipitation in an organic solvent and repeating the operation of re-precipitation recovery 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons, and the like, and it is preferable to use three or more kinds of poor solvents selected from these because the purification efficiency is further improved.

The molecular weight of the side chain polymer (A) of the present invention is measured by the GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained coating film, the workability at the time of forming the coating film, and the uniformity of the coating film. The weight average molecular weight obtained is preferably 2000 to 10000, more preferably 5000 to 100,000.

When the side chain polymer which is the component (A) of the present invention further contains the side chain represented by the formula (0), the content thereof is from the viewpoint of improving reliability and affecting the liquid crystal orientation. , 20 mol% or less is preferable, 10 mol% or less is more preferable, and 5 mol% or less is further preferable.

When the side chain type polymer which is the component (A) of the present invention further contains the side chain (b-2), the content is 80 mol from the viewpoint of improving reliability and affecting the liquid crystal orientation. % Or less is preferable, 60 mol% or less is more preferable, and 40 mol% or less is further preferable.

The side chain type polymer which is the component (A) of the present invention is a photoreactive side chain, a side chain represented by the above formula (b), a liquid crystal side chain, and a side chain represented by the above formula (0). , Other side chains other than the above side chain (b-2) may be contained. The total content of the photoreactive side chain, liquid crystal side chain, side chain represented by the above formula (0), and the above side chain (b-2) of the component (A) is 100%. If not, it is the rest.

The ratio of these side chains can be controlled by adjusting the mole fraction of the monomer giving each side chain when producing the side chain type polymer.

<< (B) component >>
The specific compound in the present invention is a heteropolyacid. The heteropolyacid in the present invention is a concept including a free acid and its neutral and acid salts. Here, the acid salt means a salt of a heteropolyacid (HPA) in which some of the hydrogen ions are replaced with basic cations, for example, alkali metal cations. Therefore, the heteropolyacid used in the catalyst in the present invention includes a free acid and a coordinated salt thereof, in which the anion exists as a complex high molecular weight substance. Typically, the anion contains a multivalent metal atom with 2 to 18 oxygen bonds, which is called a peripheral atom. These peripheral atoms symmetrically surround one or more central atoms. The peripheral atom is usually at least one selected from the group consisting of one or more molybdenum, tungsten, vanadium, niobium, tantalum, and other metals. The central atom is usually silicon or phosphorus, but may contain elements belonging to Group IA-VIIA and Group VIII of the Periodic Table of the Elements. Ions of these elements include, for example, cupric ion; divalent beryllium, zinc, cobalt or nickel ions; trivalent boron, aluminum, gallium, iron, cerium, arsenic, antimony, phosphorus, bismuth and chromium. Or rhodium ions; tetravalent silicon, germanium, tin, titanium, zirconium, vanadium, sulfur, tellurium, manganese, nickel, platinum, thorium, hafnium, cerium ions, and other rare earth ions; pentavalent Phosphorus, arsenic, vanadium, antimony ions; hexavalent tellurium ions; and heptavalent iodine ions can be mentioned. Heteropolyacids are also known as "polyoxoanions", "polyoxometalates" or "metal oxide clusters". Typical anion structures include the Keggin structure, the Wells-Dawson structure, and the Anderson-Evans-Perloff structure (all named after pioneering researchers in the field. Was done).

Typically, it has a structure in which a heteroatom is located at the center of a molecule, which is represented by a Keggin type chemical structure represented by the following formula [1-1] or a Dawson type chemical structure represented by the formula [1-2]. , Vanadium (V), molybdenum (Mo), tungsten (W) and other oxyacids, isopolic acid, and dissimilar element oxyacids are condensed to form a polyacid. Oxygen acids of such dissimilar elements mainly include oxygen acids of silicon (Si), phosphorus (P), and arsenic (As).

Heteropolyacids usually have a high molecular weight of, for example, about 700 to 8500, and may adopt a dimeric complex structure. Heteropolyacids also have relatively high solubility in polar solvents such as water and other oxygen-containing solvents. This solubility is known to increase when the heteropolyacid takes the form of a free acid or certain salts and can be adjusted by selecting the appropriate counterion.

Specific examples of the heteropolyacid compound include phosphotungstic acid, phosphomolybdic acid, silicate tungstic acid, silicate tungstic acid, phosphomolybdic acid or a salt thereof, and it is preferable to use these in the present invention. Further, these may be used alone or in combination of two or more types.

More specifically, the following can be exemplified; phosphorus-12-tungstate (H ₃ [PW ₁₂ O ₄₀ ] xH ₂ O), phosphorus-12-molybdic acid (H ₃ [PMo ₁₂ O ₄₀ ] xH _2). O), Kay-12-tungstate (H ₄ [SiW ₁₂ O ₄₀ ] xH ₂ O), Kay-12-sodium tungstate (H ₃ Na [SiW ₁₂ O ₄₀ ] xH ₂ O), Kay-12- Molybdate (H ₄ [SiMo ₁₂ O ₄₀ ] xH ₂ O), potassium phosphotungstate (K ₆ [P ₂ W ₁₈ O ₆₂ ] xH ₂ O), sodium molybdate (Na ₃ [PMo ₁₂ O ₄₀ ] xH ₂ O), ammonium diphosphorybdate ((NH ₄ ) ₆ [P ₂ Mo ₁₈ O ₆₂ ] xH ₂ O), sodium nickel-tungstate (Na ₄ [NiW ₆ O ₂₄ H ₆ ] xH ₂ O), Ammonium dicobalt-ammonium molybdate ((NH ₄ ) [Co ₂ Mo ₁₀ O ₃₆ ] xH ₂ O), hydrogen cesium tungstate (Cs ₃ H [SiW ₁₂ O ₄₀ ] xH ₂ O), potassium phosphoribdodivanadium acid (K ₅ [PMoV ₂ O ₄₀ ] xH ₂ O).

The heteropolyacid compound in the present invention is available as a commercially available product, and can also be synthesized by a known method.
Heteropolyacids can be obtained as commercial products or appropriately synthesized according to known synthetic methods even if the number of elements is large or small from the structure represented by the general formula in quantitative analysis such as elemental analysis. As long as it is used, it can be used in the present invention.

The preferable content of the heteropolyacid of the component (B) in the composition is 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the component (A).

<< (C) Organic Solvent >>
The organic solvent used in the polymer composition used in the present invention is not particularly limited as long as it is an organic solvent that dissolves the resin component. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, Dimethyl sulfoxide, hexamethyl sulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethylamyl ketone, methylnonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglime, 4-hydroxy-4-methyl-2-pentanone, propylene glycol mono Acetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, Examples thereof include dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, and tripropylene glycol methyl ether. These may be used alone or in combination.

The polymer composition used in the present invention may contain components other than the above components (A), (B) and (C). Examples thereof include solvents and compounds that improve film thickness uniformity and surface smoothness when the polymer composition is applied, compounds that improve the adhesion between the liquid crystal alignment film and the substrate, and the like. , Not limited to this.

Specific examples of the solvent (poor solvent) for improving the uniformity of the film thickness and the surface smoothness include the following.
For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol mono. Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether , Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tri Propropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3- Methyl methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy- 2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, Propropylene glycol- Low levels of 1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate ester, ethyl lactate ester, n-propyl ester lactate, n-butyl ester lactate, isoamyl lactate, etc. Examples thereof include a solvent having a surface tension.

These poor solvents may be used alone or in admixture of a plurality of types. When the above-mentioned solvent is used, it is preferably 5% by mass to 80% by mass, more preferably 5% by mass, so as not to significantly reduce the solubility of the entire solvent contained in the polymer composition. Is 20% by mass to 60% by mass.

Examples of the compound for improving the uniformity of the film thickness and the surface smoothness include a fluorine-based surfactant, a silicone-based surfactant, a nonion-based surfactant, and the like.
More specifically, for example, Ftop (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), Megafuck (registered trademark) F171, F173, R-30 (manufactured by DIC), Florard FC430, FC431. (Sumitomo 3M), Asahi Guard (registered trademark) AG710 (Asahi Glass), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (made by AGC Seimi Chemical), etc. Be done. The ratio of these surfactants used is preferably 0.01 parts by mass to 2 parts by mass, and more preferably 0.01 parts by mass to 1 part by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. It is a mass part.

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds.
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane. , N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl- 1,4,7-Triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxy Examples thereof include silane and N-bis (oxyethylene) -3-aminopropyltriethoxysilane.

Furthermore, in addition to improving the adhesion between the substrate and the liquid crystal alignment film, the following phenoplast-based or epoxy group-containing compounds are added for the purpose of preventing deterioration of electrical characteristics due to the backlight when the liquid crystal display element is configured. The agent may be contained in the polymer composition. Specific phenoplast-based additives are shown below, but are not limited to this structure.

Specific epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-Hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N', N', -tetraglycidyl-m-xylene diamine, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N, N', N',-tetraglycidyl-4,4'-diaminodiphenylmethane Etc. are exemplified.

When a compound that improves adhesion to a substrate is used, the amount used is preferably 0.1 part by mass to 30 parts by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. , More preferably 1 part by mass to 20 parts by mass. If the amount used is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected, and if it is more than 30 parts by mass, the orientation of the liquid crystal may deteriorate.

A photosensitizer can also be used as the additive. Colorless sensitizers and triplet sensitizers are preferred.
Photosensitizers include aromatic nitro compounds, coumarins (7-diethylamino-4-methylcoumarin, 7-hydroxy4-methylcoumarin), ketocoumarins, carbonylbiscoumarins, aromatic 2-hydroxyketones, and amino substitutions. , Aromatic 2-hydroxyketone (2-hydroxybenzophenone, mono- or di-p- (dimethylamino) -2-hydroxybenzophenone), acetophenone, anthraquinone, xanthone, thioxanthone, benzanthron, thiazolin (2-benzoylmethylene-3) -Methyl-β-naphthiazoline, 2- (β-naphthoylmethylene) -3-methylbenzothiazolin, 2- (α-naphthoylmethylene) -3-methylbenzothiazolin, 2- (4-biphenoylmethylene)- 3-Methylbenzothiazolin, 2- (β-naphthoyl methylene) -3-methyl-β-naphthiazoline, 2- (4-biphenoyl methylene) -3-methyl-β-naphthiazoline, 2- (p-fluoro) Benzoylmethylene) -3-methyl-β-naphthiazoline), oxazoline (2-benzoylmethylene-3-methyl-β-naphthoxazoline, 2- (β-naphthoylmethylene) -3-methylbenzoxazoline, 2- (α) -Naftylmethylene) -3-methylbenzoxazoline, 2- (4-biphenoylmethylene) -3-methylbenzoxazoline, 2- (β-naphthoylmethylene) -3-methyl-β-naphthoxazoline, 2-( 4-Bifenoylmethylene) -3-methyl-β-naphthoxazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-β-naphthoxazoline), benzothiazole, nitroaniline (m- or p-nitroaniline, 2,4,6-trinitroaniline) or nitroacenaften (5-nitroacenaften), (2-[(m-hydroxy-p-methoxy) styryl] benzothiazole, benzoin alkyl ether, N-alkylated phthalone, Acetphenone ketal (2,2-dimethoxyphenyletanone), naphthalene, anthracene (2-naphthalenemethanol, 2-naphthalenecarboxylic acid, 9-anthracenemethanol, and 9-anthracenecarboxylic acid), benzopyran, azoindolisin, merocmarin, etc. is there.
Preferred are aromatic 2-hydroxyketones (benzophenone), coumarin, ketocoumarin, carbonyl biscumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal.

[Preparation of polymer composition]
The polymer composition of the present invention contains a photosensitive side chain polymer as a component (A), a heteropolyacid as a component (B), and an organic solvent as a component (C). The polymer composition of the present invention, in addition to the components (A), (B) and (C), further improves the film thickness uniformity and surface smoothness when the polymer composition is applied. It can also contain a solvent, a compound, a compound that improves the adhesion between the liquid crystal alignment film and the substrate, and the like. Then, other additives can be contained as long as the effects of the present invention are not impaired.

The method for preparing the polymer composition of the present invention is not particularly limited. As a preparation method, for example, a method of mixing the component (B) in a predetermined ratio with a solution of the component (A) dissolved in a solvent (C) to obtain a uniform solution, or at an appropriate stage of this preparation method. , If necessary, a method of further adding and mixing other additives can be mentioned.

In the preparation of the polymer composition of the present invention, the solution of the specific copolymer obtained by the polymerization reaction in the solvent can be used as it is. In this case, for example, the component (B) and the like are added to the solution of the component (A) to make a uniform solution. At this time, an additional solvent may be added for the purpose of adjusting the concentration. At this time, the solvent used in the process of producing the component (A) and the solvent used for adjusting the concentration of the polymer composition may be the same or different.

Further, the prepared solution of the polymer composition is preferably used after being filtered using a filter having a pore size of about 0.2 μm or the like.
The polymer composition used in the present invention is preferably prepared as a coating liquid so as to be suitable for forming a liquid crystal alignment film. That is, the polymer composition used in the present invention is preferably prepared as a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component is a resin component containing a photosensitive side-chain type polymer capable of exhibiting liquid crystallinity as described above. At that time, the content of the resin component is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and particularly preferably 3% by mass to 10% by mass.

In the polymer composition of the present embodiment, the above-mentioned resin component may be only a photosensitive side-chain type polymer capable of exhibiting the liquid crystal property which is the above-mentioned component (A), but the liquid crystal expression ability and the liquid crystal expression ability and Other polymers may be mixed as long as the photosensitive performance is not impaired. At that time, the content of the other polymer in the resin component is 0.5% by mass to 80% by mass, preferably 1% by mass to 50% by mass.
Examples of such other polymers include polymers composed of poly (meth) acrylate, polyamic acid, polyimide, etc., and are not the above-mentioned component (A).

<Manufacturing method of substrate having liquid crystal alignment film> and <Manufacturing method of liquid crystal display element>
The method for manufacturing a substrate having a liquid crystal alignment film and the method for manufacturing a liquid crystal display element are as follows.
[I] A step of applying the polymer composition of the present invention on a substrate having a conductive film for driving a transverse electric field to form a coating film;
[II] A step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and a step of heating the coating film obtained in [III] [II];
Have.
Through the above steps, a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element to which orientation control ability is imparted can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

Further, by preparing a second substrate in addition to the obtained substrate (first substrate), a transverse electric field drive type liquid crystal display element can be obtained.
As the second substrate, the above steps [I] to [III] (for driving a transverse electric field) are used, except that a substrate having no conductive film for driving a transverse electric field is used instead of the substrate having a conductive film for driving a transverse electric field. Since a substrate having no conductive film is used, for convenience, in the present application, steps [I'] to [III'] may be abbreviated) to have a liquid crystal alignment film to which orientation control ability is imparted. 2 substrates can be obtained.

The method for manufacturing a transverse electric field drive type liquid crystal display element is as follows.
[IV] A step of obtaining a liquid crystal display element by arranging the first and second substrates obtained above so as to face each other so that the liquid crystal alignment films of the first and second substrates face each other via the liquid crystal.
Have. This makes it possible to obtain a transverse electric field drive type liquid crystal display element.

Hereinafter, each of the steps [I] to [III] and [IV] included in the production method of the present invention will be described.
<Step [I]>
In step [I], a photosensitive side-chain polymer, which is a component (A), which exhibits liquid crystallinity in a predetermined temperature range, is a component (B) on a substrate having a conductive film for driving a transverse electric field. A polymer composition containing a heteropolyacid and an organic solvent as a component (C) is applied to form a coating film.

<Board>
The substrate is not particularly limited, but when the liquid crystal display element to be manufactured is a transmissive type, it is preferable to use a highly transparent substrate. In that case, the present invention is not particularly limited, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used.
Further, in consideration of application to a reflective liquid crystal display element, an opaque substrate such as a silicon wafer can also be used.

<Conducting film for driving a transverse electric field>
The substrate has a conductive film for driving a transverse electric field.
Examples of the conductive film include, but are not limited to, ITO (Indium Tin Oxide: indium tin oxide) and IZO (Indium Zinc Oxide: indium zinc oxide) when the liquid crystal display element is a transmissive type.
Further, in the case of a reflective liquid crystal display element, examples of the conductive film include a material that reflects light such as aluminum, but the conductive film is not limited thereto.
As a method for forming a conductive film on a substrate, a conventionally known method can be used.

In addition to the above-mentioned polymer compositions, dielectrics and conductive substances can be used for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal alignment film as long as the effects of the present invention are not impaired. Furthermore, a crosslinkable compound may be added for the purpose of increasing the hardness and density of the film when it is formed into a liquid crystal alignment film.

The method of applying the above-mentioned polymer composition on a substrate having a conductive film for driving a transverse electric field is not particularly limited.
Industrially, the coating method is generally performed by screen printing, offset printing, flexographic printing, inkjet method, or the like. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method (rotary coating method), a spray method, and the like, and these may be used depending on the purpose.

After applying the polymer composition on a substrate having a conductive film for driving a transverse electric field, the temperature is 50 to 200 ° C., preferably 50 to 200 ° C. by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. A coating can be obtained by evaporating the solvent at 150 ° C. The drying temperature at this time is preferably lower than the liquid crystal phase expression temperature of the side chain polymer.
If the thickness of the coating film is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, the thickness is preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm. Is.
It is also possible to provide a step of cooling the substrate on which the coating film is formed to room temperature after the step [I] and before the subsequent step [II].

<Step [II]>
In step [II], the coating film obtained in step [I] is irradiated with polarized ultraviolet rays. When the film surface of the coating film is irradiated with polarized ultraviolet rays, the substrate is irradiated with polarized ultraviolet rays from a certain direction via a polarizing plate. As the ultraviolet rays to be used, ultraviolet rays having a wavelength in the range of 100 nm to 400 nm can be used. Preferably, the optimum wavelength is selected through a filter or the like depending on the type of coating film used. Then, for example, ultraviolet rays having a wavelength in the range of 290 nm to 400 nm can be selected and used so that the photocrosslinking reaction can be selectively induced. As the ultraviolet rays, for example, light emitted from a high-pressure mercury lamp can be used.

The irradiation amount of polarized ultraviolet rays depends on the coating film used. The irradiation amount is polarized ultraviolet rays that realize the maximum value of ΔA (hereinafter, also referred to as ΔAmax), which is the difference between the ultraviolet absorptance in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorptivity in the vertical direction in the coating film. The amount is preferably in the range of 1% to 70%, and more preferably in the range of 1% to 50%.

<Step [III]>
In step [III], the coating film irradiated with ultraviolet rays polarized in step [II] is heated. Orientation control ability can be imparted to the coating film by heating.
For heating, a heating means such as a hot plate, a heat circulation type oven, or an IR (infrared) type oven can be used. The heating temperature can be determined in consideration of the temperature at which the liquid crystal property of the coating film to be used is exhibited.

The heating temperature is preferably within the temperature range of the temperature at which the side chain polymer exhibits liquid crystallinity (hereinafter referred to as the liquid crystallinity development temperature). In the case of a thin film surface such as a coating film, the liquid crystallinity development temperature on the coating film surface may be lower than the liquid crystallinity development temperature when a photosensitive side-chain polymer capable of exhibiting liquid crystallinity is observed in bulk. is expected. Therefore, the heating temperature is more preferably within the temperature range of the liquid crystal appearance temperature on the surface of the coating film. That is, the temperature range of the heating temperature after irradiation with polarized ultraviolet rays is 10 ° C lower than the lower limit of the temperature range of the liquid crystal development temperature of the side chain polymer to be used, and 10 ° C lower than the upper limit of the liquid crystal temperature range. The temperature is preferably in the range up to the temperature. If the heating temperature is lower than the above temperature range, the effect of amplifying anisotropy due to heat in the coating film tends to be insufficient, and if the heating temperature is too high above the above temperature range, the state of the coating film is in a state. Tends to be close to an isotropic liquid state (isotropic phase), in which case self-assembly can make it difficult to reorient in one direction.
The liquid crystal development temperature is equal to or higher than the glass transition temperature (Tg) at which the side chain polymer or the coating surface undergoes a phase transition from the solid phase to the liquid crystal phase, and the liquid crystal phase to the isotropic phase (isotropic phase). It refers to a temperature below the isotropic phase transition temperature (Tiso) that causes a phase transition.

By having the above steps, the production method of the present invention can realize highly efficient introduction of anisotropy into the coating film. Then, a substrate with a liquid crystal alignment film can be manufactured with high efficiency.

<Step [IV]>
In the [IV] step, the same as the substrate (first substrate) having the liquid crystal alignment film on the conductive film for driving the transverse electric field obtained in [III], and the above-mentioned [I'] to [III']. The obtained substrate with a liquid crystal alignment film (second substrate) having no conductive film is placed facing each other so that both liquid crystal alignment films face each other via the liquid crystal, and the liquid crystal cell is formed by a known method. This is a step of manufacturing and manufacturing a transverse electric field drive type liquid crystal display element. In steps [I'] to [III'], except that in step [I], a substrate having no transverse electric field driving conductive film was used instead of the substrate having the transverse electric field driving conductive film. It can be carried out in the same manner as in steps [I] to [III]. Since the only difference between the steps [I] to [III] and the steps [I'] to [III'] is the presence or absence of the conductive film described above, the description of the steps [I'] to [III'] is omitted. To do.

To give an example of manufacturing a liquid crystal cell or a liquid crystal display element, the above-mentioned first and second substrates are prepared, a spacer is sprayed on the liquid crystal alignment film of one of the substrates, and the liquid crystal alignment film surface is on the inside. In this way, the other substrate is bonded and the liquid crystal is injected under reduced pressure to seal it, or the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacer is sprayed and then the substrate is bonded and sealed. , Etc. can be exemplified. At this time, it is preferable to use a substrate having an electrode having a structure like a comb tooth for driving a transverse electric field as the substrate on one side. The diameter of the spacer at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. This spacer diameter determines the distance between the pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.

In the method for producing a substrate with a coating film of the present invention, the polymer composition is applied onto the substrate to form a coating film, and then polarized ultraviolet rays are irradiated. Next, by heating, highly efficient anisotropy is introduced into the side chain type polymer film, and a substrate with a liquid crystal alignment film having a liquid crystal orientation control ability is manufactured.
The coating film used in the present invention realizes highly efficient introduction of anisotropy into the coating film by utilizing the principle of molecular reorientation induced by the photoreaction of side chains and self-assembly based on liquid crystallinity. .. In the production method of the present invention, in the case of a structure having a photocrosslinkable group as a photoreactive group in the side chain polymer, after forming a coating film on the substrate using the side chain polymer, polarized ultraviolet rays are emitted. After irradiating and then heating, a liquid crystal display element is produced.

Therefore, the coating film used in the method of the present invention is a liquid crystal alignment film having excellent orientation control ability because anisotropy is introduced with high efficiency by sequentially irradiating the coating film with polarized ultraviolet rays and heat treatment. can do.

Then, in the coating film used in the method of the present invention, the irradiation amount of polarized ultraviolet rays on the coating film and the heating temperature in the heat treatment are optimized. As a result, highly efficient introduction of anisotropy into the coating film can be realized.

The optimum irradiation amount of polarized ultraviolet rays for introducing highly efficient anisotropy into the coating film used in the present invention is such that the photosensitive group undergoes a photocrossing reaction, a photoisomerization reaction, or a photofleece rearrangement reaction in the coating film. Corresponds to the irradiation amount of polarized ultraviolet rays that optimizes the amount. As a result of irradiating the coating film used in the present invention with polarized ultraviolet rays, if the number of photosensitive groups in the side chain undergoing a photocrosslinking reaction, a photoisomerization reaction, or a photoFries rearrangement reaction is small, the amount of photoreaction is not sufficient. .. In that case, even if it is heated after that, sufficient self-organization does not proceed. On the other hand, in the coating film used in the present invention, as a result of irradiating a structure having a photocrosslinkable group with polarized ultraviolet rays, if the photosensitive group of the side chain undergoing the crosslink reaction becomes excessive, the crosslink reaction between the side chains occurs. It will go too far. In that case, the resulting membrane may become rigid and hinder the progress of self-assembly by subsequent heating. Further, in the coating film used in the present invention, as a result of irradiating a structure having a photo Fries rearrangement group with polarized ultraviolet rays, if the photosensitive groups of the side chains that undergo a photo Fries rearrangement reaction become excessive, the liquid crystal property of the coating film becomes high. Will drop too much. In that case, the liquid crystallinity of the obtained film is also lowered, which may hinder the progress of self-assembly due to subsequent heating. Further, when irradiating a structure having a photo-Fries rearrangement group with polarized ultraviolet rays, if the irradiation amount of the ultraviolet rays is too large, the side chain type polymer is photodecomposed, and the subsequent heating hinders the progress of self-assembly. May become.

Therefore, in the coating film used in the present invention, the optimum amount of the photosensitive group of the side chain undergoing a photocrosslinking reaction, a photoisomerization reaction, or a photofleece rearrangement reaction by irradiation with polarized ultraviolet rays is the side chain type polymer film. It is preferably 0.1 mol% to 40 mol%, and more preferably 0.1 mol% to 20 mol% of the photosensitive group of the above. By setting the amount of photosensitive groups in the side chain that photoreacts within such a range, self-assembly in the subsequent heat treatment proceeds efficiently, and highly efficient anisotropy can be formed in the film. Become.

In the coating film used in the method of the present invention, by optimizing the irradiation amount of polarized ultraviolet rays, a photocrosslinking reaction, a photoisomerization reaction, or a photofleece rearrangement reaction of a photosensitive group in the side chain of a side chain type polymer film is performed. Optimize the amount of. Then, in combination with the subsequent heat treatment, highly efficient introduction of anisotropy into the coating film used in the present invention is realized. In that case, the suitable amount of polarized ultraviolet rays can be determined based on the evaluation of ultraviolet absorption of the coating film used in the present invention.

That is, with respect to the coating film used in the present invention, after irradiation with polarized ultraviolet rays, the absorption of ultraviolet rays in the direction parallel to the polarization direction of the polarized ultraviolet rays and the absorption of ultraviolet rays in the direction perpendicular to the polarization direction are measured, respectively. From the measurement result of ultraviolet absorption, ΔA, which is the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorbance in the direction perpendicular to the polarization direction, is evaluated. Then, the maximum value (ΔAmax) of ΔA realized in the coating film used in the present invention and the irradiation amount of polarized ultraviolet rays to realize it are obtained. In the production method of the present invention, a preferable amount of polarized ultraviolet rays to be irradiated in the production of the liquid crystal alignment film can be determined based on the amount of polarized ultraviolet rays that realizes this ΔAmax.

In the production method of the present invention, the irradiation amount of polarized ultraviolet rays on the coating film used in the present invention is preferably in the range of 1% to 70% of the amount of polarized ultraviolet rays that realize ΔAmax, and is preferably 1% to 70%. It is more preferably within the range of 50%. In the coating film used in the present invention, the irradiation amount of polarized ultraviolet rays in the range of 1% to 50% of the amount of polarized ultraviolet rays that realize ΔAmax is 0. It corresponds to the amount of polarized ultraviolet rays that photocrosslink 1 mol% to 20 mol%.

Based on the above, in the production method of the present invention, in order to realize highly efficient introduction of anisotropy into the coating film, the suitable heating temperature as described above is set based on the liquid crystal temperature range of the side chain polymer. It is better to determine. Therefore, for example, when the liquid crystal temperature range of the side chain polymer used in the present invention is 100 ° C. to 200 ° C., it is desirable that the heating temperature after irradiation with polarized ultraviolet rays is 90 ° C. to 190 ° C. By doing so, the coating film used in the present invention is imparted with greater anisotropy.

By doing so, the liquid crystal display element provided by the present invention exhibits high reliability against external stress such as light and heat.

As described above, the substrate for the transverse electric field driven liquid crystal display element manufactured by the method of the present invention or the transverse electric field driven liquid crystal display element having the substrate has excellent reliability and has a large screen and high definition. It can be suitably used for liquid crystal televisions and the like.
Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

The methacrylic monomers M1 and M2 used in the examples, HBAGE as a monomer having a cross-linking group, and A1 as a monomer having an amide group are shown below.
In addition, M1 and M2 were synthesized as follows, respectively. That is, M1 was synthesized by the synthetic method described in Patent Document (WO2011-084546). M2 was synthesized by the synthesis method described in Patent Document (Japanese Patent Laid-Open No. 9-118717).
Monomer A1 was synthesized by the synthetic method described in Patent Document (WO2014 / 054785).
As HBAGE (hydroxybutyl acrylate glycidyl ether), one that can be purchased commercially was used.

In addition, the abbreviations of the reagents used in this example are shown below.
(Organic solvent)
THF: tetrahydrofuran.
NMP: N-ethyl-2-pyrrolidone.
BCS: Butyl cellosolve (polymerization initiator)
AIBN: 2,2'-azobisisobutyronitrile.
(Additive)
Phosphor Tungstic Acid (PWA): Made by Nippon Shinkinzoku Co., Ltd.

<Polymer synthesis example 1>
M1 (3.98 g), M2 (5.51 g), GMA (0.32 g), A1 (0.07 g) are dissolved in THF (40.0 g), degassed with a diaphragm pump, and then AIBN. (0.24 g) was added and degassing was performed again. Then, the reaction was carried out at 60 ° C. for 6 hours to obtain a polymer solution of methacrylate. This polymer solution was added dropwise to methanol (300 ml) and the resulting precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure to obtain a methacrylate polymer powder P1.

<Example 1>
NMP (5.6 g) was added to the methacrylate polymer powder P1 (0.4 g) obtained in Polymer Synthesis 1, and the mixture was dissolved by stirring at room temperature for 30 minutes. PWA (0.004 g) was added to this solution, and the mixture was stirred and dissolved at room temperature for 30 minutes, and BCS (4.0 g) was further added and stirred to obtain a polymer solution T1. This polymer solution was used as a liquid crystal alignment agent for forming a liquid crystal alignment film as it was.

<Examples 2 to 3>
The composition shown in Table 1 was adjusted using the same method as in Example 1 to obtain liquid crystal alignment agents T2 to T3 in Examples 2 to 3. Further, the liquid crystal alignment agent C1 of Comparative Example 1 was obtained by using the same method as in Example 1 except that PWA was not added.

<Manufacturing of liquid crystal cell>
The liquid crystal alignment agent (T1) obtained in Example 1 is filtered through a 0.45 μm filter, spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 70 ° C. for 90 seconds, and then has a film thickness of 100 nm. A liquid crystal alignment film was formed. Next, the coating film surface was irradiated with ultraviolet rays of 313 nm at 15 mJ / cm2 via a polarizing plate and then heated on a hot plate at 140 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two such substrates with a liquid crystal alignment film are prepared, a spacer of 6 μm is installed on the liquid crystal alignment film surface of one of the substrates, and then the two substrates are combined so that the rubbing directions are parallel to each other, and the liquid crystal injection port is used. The surrounding area was sealed leaving a cell gap of 4 μm to prepare an empty cell. Liquid crystal MLC-3019 (manufactured by Merck Co., Ltd.) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell in which the liquid crystals were aligned in parallel.
A liquid crystal cell was similarly prepared using the liquid crystal alignment agents T2 to T3 obtained in Examples 2 to 3 and the liquid crystal alignment agent C1 obtained in Comparative Example 1.

<VHR evaluation>
In the evaluation of VHR, a voltage of 1 V was applied to the obtained liquid crystal cell at a temperature of 70 ° C. for 60 μs, the voltage after 16.67 ms and 1000 ms was measured, and the voltage retention rate was determined by how much the voltage could be maintained. Calculated as. The VHR measured under the condition of 16.67 ms was defined as VHR1, and the VHR measured under the condition of 1000 ms was defined as VHR2. A voltage retention measuring device VHR-1 manufactured by Toyo Corporation was used for measuring the voltage retention.
Table 2 shows the results of VHR of the liquid crystal alignment agents of Examples 1 to 3 and Comparative Examples.

From Table 2, it can be seen that by introducing phosphotungstic acid in Examples 1 to 3, both VHR1 and VHR2 are improved as compared with Comparative Example 1 in which the additive is not introduced.

Claims (6)

(A) A main chain composed of (meth) acrylate , a photosensitive side chain represented by the following formula (2), and a photosensitive side chain represented by the following formula (0) while exhibiting liquid crystallinity in a predetermined temperature range. side chain, and a polymer having a side chain (b-2) having a pyridyl group,
A polymer composition containing (B) a heteropolyacid and (C) an organic solvent.

(In the formula, A, B, and D are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO. Represents -O- or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
Y ₂ is a divalent benzene ring;
R represents a hydroxy group;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When it represents CH- and the number of Xs is 2, the Xs may be the same or different;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bonded is an aromatic ring. When the number of Ps is 2 or more, the Ps may be the same or different, and when the number of Qs is 2 or more, the Qs may be the same or different;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond.

In the formula, A and B are independently single-bonded, -O-, -CH _2- , -COO-, -OCO-, -CONH-, -NH-CO-, -CH = CH-CO-O-. , Or -O-CO-CH = CH-;
S is an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atom bonded to them may be replaced with a halogen group;
X is a single bond, -COO-, -OCO-, -N = N-, -CH = CH-, -C≡C-, -CH = CH-CO-O-, or -O-CO-CH = When CH-represents and the number of Xs is 2, the Xs may be the same or different;
P and Q are independently selected from the group consisting of a divalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and a combination thereof. It is a group; however, when X is -CH = CH-CO-O-, -O-CO-CH = CH-, P or Q on the side to which -CH = CH- is bound is an aromatic ring;
l1 is 0 or 1;
l2 is an integer from 0 to 2;
When both l1 and l2 are 0, A also represents a single bond when T is a single bond;
When l1 is 1, B also represents a single bond when T is a single bond;
G is the following formula (G-1), (G-2), (G-3) and (G-4).

(In the formula, the broken line represents the bond, R ⁵⁰ represents a group selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, and a phenyl group, and ^{when there are a plurality of R 50s,} they are the same or different from each other. T is an integer of 1 to 7, J represents O, S, NH or NR ⁵¹ , and R ⁵¹ represents a group selected from alkyl and phenyl groups having 1 to 3 carbon atoms). Is the basis for this. Polymer composition of claim 1 Symbol placement heteropoly acid is phosphotungstic acid.
The component (A) is the following formulas (21) to (31).
(In the formula, A and B have the same definition as above;
Y ₃ is a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and alicyclic hydrocarbons having 5 to 8 carbon atoms, and, with a group selected from the group consisting of Yes, the hydrogen atoms attached to them may be independently _{substituted with -NO 2} , -CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;
R ₃ contains hydrogen atom, -NO ₂ , -CN, -CH = C (CN) ₂ , -CH = CH-CN, halogen group, monovalent benzene ring, naphthalene ring, biphenyl ring, furan ring, and nitrogen. Represents a heterocycle, an alicyclic hydrocarbon having 5 to 8 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms;
One of q1 and q2 is 1 and the other is 0;
l represents an integer of 1 to 12, m represents an integer of 0 to 2, but in equations (23) to (24), the sum of all m is 2 or more, and equations (25) to (26). ), The sum of all m is 1 or more, and m1, m2, and m3 independently represent integers 1 to 3;
R ₂ is a hydrogen atom, -NO ₂ , -CN, a halogen group, a monovalent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, and an alicyclic hydrocarbon having 5 to 8 carbon atoms. And represents an alkyl group or an alkyloxy group;
Z ₁ and Z ₂ represent single bond, -CO-, -CH ₂ O-, -CH = N-, -CF _2- )
The polymer composition according to claim 1 or 2, further comprising any one liquid crystal side chain selected from the group consisting of.

[I] A step of applying the polymer composition according to any one of claims 1 to 3 onto a substrate having a conductive film for driving a transverse electric field to form a coating film;
[II] A step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and a step of heating the coating film obtained in [III] [II];
A method for manufacturing a substrate having a liquid crystal alignment film, which obtains a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which an orientation control ability is imparted. A liquid crystal alignment film for a transverse electric field drive type liquid crystal display element obtained by using the polymer composition according to any one of claims 1 to 3. The horizontal electric field driven liquid crystal display element having the liquid crystal alignment film for the horizontal electric field driven liquid crystal display element according to claim 5.