CN105431770B

CN105431770B - Method for manufacturing substrate having liquid crystal alignment film for in-plane switching liquid crystal display element

Info

Publication number: CN105431770B
Application number: CN201480043238.0A
Authority: CN
Inventors: 片山雅章; 根木隆之; 川月喜弘; 近藤瑞穂
Original assignee: Public University Corp Hyogo Prefecture University; Nissan Chemical Corp
Current assignee: Public University Corp Hyogo Prefecture University; Nissan Chemical Corp
Priority date: 2013-05-31
Filing date: 2014-05-30
Publication date: 2021-06-04
Anticipated expiration: 2034-05-30
Also published as: JPWO2014192922A1; TWI668491B; KR20160014691A; TW201510611A; CN105431770A; KR102191954B1; WO2014192922A1

Abstract

The invention provides a transverse electric field driving type liquid crystal display element which is endowed with orientation control capability with high efficiency, has excellent afterimage characteristics, and further has a liquid crystal orientation film with high end linearity and small end bulge. The present invention solves the above-mentioned problems by a method for producing a substrate having a liquid crystal alignment film, comprising [ I ] applying a polymer composition onto a substrate having a conductive film for driving a transverse electric field to form a coating film, the polymer composition comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer, has a boiling point of not less than 10 mass% and not less than 180 ℃, and contains a solvent selected from the group consisting of solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or a poor solvent containing propylene glycol monobutyl ether; [ II ] irradiating the obtained coating film with polarized ultraviolet rays; [ III ] the resulting coating film was heated to obtain a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, to which an alignment control ability was imparted.

Description

Method for manufacturing substrate having liquid crystal alignment film for in-plane switching liquid crystal display element

Technical Field

The present invention relates to a method for manufacturing a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element. More particularly, the present invention relates to a novel method for manufacturing a liquid crystal display element having a liquid crystal alignment film with excellent afterimage characteristics, high linearity of an end portion, and small protrusion of an end portion.

Background

Liquid crystal display elements are known as display devices having light weight, thin cross-section, and low power consumption, and have been used for large-sized television applications and the like in recent years, and remarkable progress has been made. The liquid crystal display element is configured by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes, for example. Also, in the liquid crystal display element, an organic film containing an organic material is used as a liquid crystal alignment film to cause the liquid crystal to assume a desired alignment state between the substrates.

That is, the liquid crystal alignment film is a component of the liquid crystal display element, is formed on a surface of the substrate that is in contact with the liquid crystal and holds a role of aligning the liquid crystal in a specific direction between the substrates. Further, the liquid crystal alignment film is sometimes required to have a function of aligning the liquid crystal in a specific direction, for example, a direction parallel to the substrate, and a function of controlling the pretilt angle of the liquid crystal. The ability of such a liquid crystal alignment film to control the alignment of liquid crystals (hereinafter referred to as alignment control ability) is imparted by performing alignment treatment on an organic film constituting the liquid crystal alignment film.

As an alignment treatment method of a liquid crystal alignment film for imparting alignment controllability, a brushing method has been known. The brushing method refers to the following method: with respect to an organic film of polyvinyl alcohol, polyamide, polyimide, or the like on a substrate, the surface thereof is rubbed (brushed) in a constant direction with a cloth of cotton, nylon, polyester, or the like, thereby aligning the liquid crystal in the rubbing direction (brushing direction). This brushing method is used in the production process of a conventional liquid crystal display element because it can easily realize a relatively stable liquid crystal alignment state. 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 is mainly selected.

However, the brush rubbing method of rubbing the surface of a liquid crystal alignment film made of polyimide or the like has a problem of generating dust and static electricity. Further, in recent years, the liquid crystal display element has become more highly clear, and the surface of the liquid crystal alignment film has not been uniformly rubbed with a cloth due to irregularities caused by the electrode on the substrate or the switching active element for driving the liquid crystal, and thus uniform liquid crystal alignment has not been achieved.

Therefore, as another alignment treatment method of a liquid crystal alignment film without brushing, a photo-alignment method has been actively studied.

In the photo-alignment method, there are various methods of forming anisotropy in an organic film constituting a liquid crystal alignment film by linearly polarized light or collimated light, and aligning liquid crystal according to the anisotropy.

As a main photo-alignment method, a decomposition type photo-alignment method is known. For example, a polyimide film is irradiated with polarized ultraviolet light, and anisotropic decomposition occurs due to the polarization direction dependency of ultraviolet absorption of the molecular structure. Then, the liquid crystal is aligned by the polyimide remaining without decomposition (see, for example, patent document 1).

Further, photo-alignment methods of photo-crosslinking type and photo-isomerization type are also known. For example, polyvinyl cinnamate is irradiated with polarized ultraviolet rays to cause dimerization reaction (crosslinking reaction) of double bond portions of 2 side chains parallel to polarized light. Then, the liquid crystal is aligned in a direction perpendicular to the polarization direction (see, for example, non-patent document 1). In addition, when a side chain type polymer having azobenzene in the side chain is used, polarized ultraviolet rays are irradiated to cause an isomerization reaction of the azobenzene portion of the side chain parallel to the polarized light, and the liquid crystal is aligned in a direction perpendicular to the polarization direction (for example, see non-patent document 2).

As in the above example, in the method of aligning the liquid crystal alignment film by the photo-alignment method, it is not necessary to perform brushing, and there is no fear of generation of dust or static electricity. Further, the alignment treatment can be performed even on the substrate of the liquid crystal display element having the surface with irregularities, and thus the method for aligning the liquid crystal alignment film is suitable for an industrial production process.

In addition, when a liquid crystal alignment agent (also referred to as a "coating solution") for forming a liquid crystal alignment film is applied to a substrate, it is industrially performed by a flexible printing method, an inkjet coating method, or the like. In this case, among the solvents of the coating solution, N-methyl-2-pyrrolidone, γ -butyrolactone, and the like, which are solvents having excellent resin solubility (also referred to as "good solvents"), butyl cellosolve, which is a solvent having low resin solubility (also referred to as "poor solvent"), and the like are usually mixed and used in order to improve the coating film uniformity of the liquid crystal alignment film (see, for example, patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3893659

Patent document 2: japanese laid-open patent publication No. 2-37324

Non-patent document

Non-patent document 1: m.shadt et al, jpn.j.appl.phys.31,2155(1992).

Non-patent document 2: ichimura et al, chem.rev.100,1847(2000).

Disclosure of Invention

Problems to be solved by the invention

As described above, the photo-alignment method has a significant advantage in that it does not require a brushing process, as compared with a brushing method which has been industrially used as an alignment treatment method for a liquid crystal display element. In addition, the optical alignment method can control the alignment control ability by changing the irradiation amount of polarized light, compared to the rubbing method in which the alignment control ability by the rubbing is almost constant. However, when the optical alignment method is intended to achieve an alignment controllability similar to that achieved by the rubbing method, a large amount of polarized light irradiation is required or stable liquid crystal alignment cannot be achieved.

For example, in the decomposition type photo-alignment method described in patent document 1, it is necessary to irradiate the polyimide film with ultraviolet light or the like emitted from a high-pressure mercury lamp with a power of 500W for 60 minutes, and it is necessary to irradiate a large amount of ultraviolet light for a long time. In addition, in the case of the dimerization type or photoisomerization type photoalignment method, a large amount of ultraviolet irradiation of about several J (joules) to several tens of J may be required. Further, in the photo-alignment method of photo-crosslinking type or photo-isomerization type, since thermal stability and photo stability of liquid crystal alignment are poor, there is a problem that alignment failure occurs and image sticking is shown when a liquid crystal display element is produced. In particular, in the liquid crystal display element of the transverse electric field driving type, since liquid crystal molecules are switched in a plane, liquid crystal alignment shift after liquid crystal driving is likely to occur, and display sticking caused by AC driving is regarded as a significant problem.

Therefore, in the photo-alignment method, highly efficient and stable liquid crystal alignment of alignment treatment is required, and a liquid crystal alignment film and a liquid crystal alignment agent capable of efficiently providing a liquid crystal alignment film with high alignment controllability are required.

In addition, in recent years, liquid crystal display elements have been used for mobile applications such as smart phones and mobile phones. In these applications, a sealant used for bonding substrates of a liquid crystal display element to each other is present at a position near an end of a liquid crystal alignment film in order to secure as many display surfaces as possible. Therefore, when the film coatability of the end portion of the liquid crystal alignment film is lowered, that is, when the end portion of the liquid crystal alignment film is not straight or the end portion thereof is raised, the adhesion effect of the sealant between the substrates may be lowered, and the display characteristics and reliability of the liquid crystal display element may be lowered.

The invention aims to provide a substrate provided with an orientation control capability with high efficiency, excellent afterimage characteristics, high end linearity and small end bulge, and a liquid crystal orientation film for a transverse electric field drive type liquid crystal display element.

Means for solving the problems

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found the following invention.

<1> a polymer composition, particularly a polymer composition for producing a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent,

the organic solvent has both a good solvent and a poor solvent for the side chain type polymer, and the good solvent having a boiling point of 180 ℃ or higher is 10 mass% or more among 100 parts by mass of the good solvent on average,

the good solvent comprises at least 1 specific good solvent selected from solvents with the boiling point of 100-230 ℃ and the surface tension of less than 41.0dyn/cm, and/or the poor solvent comprises propylene glycol monobutyl ether.

<2> in <1> above, the component (A) may have a photosensitive side chain which undergoes photocrosslinking, photoisomerization or photoFries rearrangement.

<3> in the above <1> or <2>, the specific good solvent in the component (B) may be 1 or more selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), and Propylene Glycol Monomethyl Ether (PGME).

<4> in the above <1> or <2>, the specific good solvent in the component (B) may be N-ethyl-2-pyrrolidone (NEP).

<5> in any one of the above <1> to <4>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulas (1) to (6).

Wherein A, B, D each independently represents a single bond, -O-, -CH₂-, -COO-, -OCO-, -CONH-, -NH-CO-, -CH-CO-O-or-O-CO-CH-;

s is C1-C12 alkylene, and hydrogen atoms bonded to the S are optionally substituted by halogen groups;

t is a single bond or an alkylene group having 1 to 12 carbon atoms, and a hydrogen atom bonded thereto is optionally substituted with a halogen group;

Y₁represents a ring selected from a 1-valent 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 a group in which 2 to 6 identical or different rings selected from these substituents are bonded via a bonding group B, and hydrogen atoms bonded to these are each independently optionally substituted by-COOR₀(in the formula, R₀Hydrogen atom or C1-5 alkyl group), -NO₂、-CN、-CH＝C(CN)₂-CH ═ CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms;

Y₂is a group selected from the group consisting of a 2-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a C5-C8 alicyclic hydrocarbon, and combinations thereof, and hydrogen atoms bonded thereto are each independently optionally substituted by-NO₂、-CN、-CH＝C(CN)₂-CH ═ CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms;

r represents a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to Y₁The same definition;

x represents a single bond, -COO-, -OCO-, -N-, -CH-, -C.ident.C-, -CH-CO-O-or-O-CO-CH-, and when the number of X reaches 2, X is optionally the same or different from each other;

cou represents coumarin-6-yl or coumarin-7-yl, the hydrogen atoms bonded to them each independently being optionally substituted by-NO₂、-CN、-CH＝C(CN)₂-CH ═ CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy 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 each independently a group selected from the group consisting of a 2-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a C5-8 alicyclic hydrocarbon, and combinations thereof; wherein, when X is-CH-CO-O-, -O-CO-CH-and-CH-the side to which-CH-is bonded, P or Q is an aromatic ring, when the number of P is 2 or more, P is optionally the same as or different from each other, and when the number of Q is 2 or more, Q is optionally the same as or different from each other;

l1 is 0 or 1;

l2 is an integer of 0 to 2;

when l1 and l2 are both 0, A represents a single bond when T is a single bond;

when l1 is 1, B represents a single bond when T is a single bond;

h and I are each independently a group selected from the group consisting of a 2-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, and combinations thereof.

<6> in any one of the above <1> to <4>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulas (7) to (10).

In the formula, A, B, D, Y₁、X、Y₂And R has the same definition as above;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, m1 and m2 represent an integer of 1 to 3;

n represents an integer of 0 to 12 (wherein, when n is 0, B is a single bond).

<7> in any one of the above <1> to <3>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulas (11) to (13).

Wherein A, X, l, m1 and R have the same meanings as defined above.

<8> in any one of <1> to <4>, the component (A) may have a photosensitive side chain represented by the following formula (14) or (15).

In the formula, A, Y₁L, m1 and m2 have the same definitions as above.

<9> in any one of <1> to <4>, the component (A) may have a photosensitive side chain represented by the following formula (16) or (17).

Wherein A, X, l and m have the same meanings as defined above.

<10> in any one of <1> to <4>, the component (A) may have a photosensitive side chain represented by the following formula (18) or (19).

In the formula, A, B, Y₁Q1, q2, m1 and m2 have the same definitions as above.

R₁Represents a hydrogen atom, -NO₂、-CN、-CH＝C(CN)₂-CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.

<11> in any one of <1> to <4>, the component (A) may have a photosensitive side chain represented by the following formula (20).

In the formula, A, Y₁X, l and m have the same definitions as above.

<12> in any one of the above <1> to <10>, the component (a) may have any one liquid crystalline side chain selected from the group consisting of the following formulas (21) to (31).

Wherein A, B, q1 and q2 have the same meanings as defined above;

Y₃is a group selected from the group consisting of 1-valent benzene ring, naphthalene ring, biphenyl ring, furan ring, nitrogen-containing heterocycle, C5-C8 alicyclic hydrocarbon, and a combination thereof, and hydrogen atoms bonded thereto are each independently optionally substituted by-NO₂CN, -a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms;

R₃represents a hydrogen atom, -NO₂、-CN、-CH＝C(CN)₂-CH ═ CH — CN, a halogen group, a 1-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing 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, wherein in the formulae (23) to (24), the sum of all m is 2 or more, in the formulae (25) to (26), the sum of all m is 1 or more, and m1, m2 and m3 each independently represents an integer of 1 to 3;

R₂represents a hydrogen atom, -NO₂CN, a halogen group, a 1-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, alicyclic hydrocarbon with 5-8 carbon atoms, and alkyl or alkoxy;

Z₁、Z₂represents a single bond, -CO-, -CH₂O-、-CH＝N-、-CF₂-。

<13> a method for producing a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which comprises the steps of:

[I] a step of applying the composition of any one of <1> to <11> on a substrate having a conductive film for driving a transverse electric field to form a coating film;

[ II ] irradiating the coating film obtained in [ I ] with polarized ultraviolet light; and

and [ III ] a step of heating the coating film obtained in [ II ].

<14> a substrate having a liquid crystal alignment film for a transverse electric field driven type liquid crystal display element, which is produced by the method <13> above.

<15> a transverse electric field driven type liquid crystal display element having the substrate <14> above.

<16> a method for manufacturing a transverse electric field driven liquid crystal display element, comprising the steps of:

preparing the substrate (1 st substrate) of the above <14 >;

a step of obtaining a2 nd substrate having a liquid crystal alignment film to which an alignment control capability is imparted by including the following steps [ I ' ], [ II ' ] and [ III ' ]; and

[ IV ] a step of disposing a1 st substrate and a2 nd substrate in opposition to each other with the liquid crystal alignment films of the 1 st substrate and the 2 nd substrate facing each other with the liquid crystal interposed therebetween to obtain a liquid crystal display element,

the processes [ I ' ], [ II ' ] and [ III ' ] are:

[ I' ] a step of forming a coating film by applying a polymer composition on a2 nd substrate, the polymer composition comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer, wherein 100 parts by mass of the good solvent on average contains 10% by mass or more of the good solvent having a boiling point of 180 ℃ or higher, the good solvent contains 1 or more specific good solvents selected from solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or the poor solvent contains propylene glycol monobutyl ether;

a step of irradiating the coating film obtained in [ I' ] with polarized ultraviolet light; and

[ III '] heating the coating film obtained in [ II' ].

<17> a transverse electric field driven type liquid crystal display element, which is manufactured by the above <16 >.

Further, the following invention is found as another aspect.

< P1> A method for manufacturing a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which comprises the steps of:

[I] a step of forming a coating film by applying a polymer composition onto a substrate having a conductive film for driving a transverse electric field, the polymer composition comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer, wherein 100 parts by mass of the good solvent on average contains 10% by mass or more of the good solvent having a boiling point of 180 ℃ or higher, the good solvent contains 1 or more specific good solvents selected from solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or the poor solvent contains propylene glycol monobutyl ether;

and [ III ] a step of heating the coating film obtained in [ II ].

< P2> in the above < P1>, the component (a) may have a photosensitive side chain which undergoes photocrosslinking, photoisomerization or photofries rearrangement.

< P3> in the above < P1> or < P2>, the specific good solvent in the component (B) may be 1 or more selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), and Propylene Glycol Monomethyl Ether (PGME).

< P4> in the above < P1> or < P2>, the specific good solvent in the component (B) may be N-ethyl-2-pyrrolidone (NEP).

< P5> in any one of the above < P1> to < P4>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulae (1) to (6).

x represents a single bond, -COO-, -OCO-, -N-, -CH-, -C.ident.C-, -CH-CO-O-, or-O-CO-CH-;

one of q1 and q2 is 1 and the other is 0;

q3 is 0 or 1;

p and Q are each independently a group selected from the group consisting of a single bond, a 2-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, a carbon number 5-8 alicyclic hydrocarbon, and a combination thereof. Wherein, X is-CH-CO-O-, -O-CO-CH-when, -CH-is bonded to the side of P or Q is an aromatic ring;

< P6> in any one of the above < P1> to < P4>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulae (7) to (10).

In the formula, A, B, D, Y₁、X、Y₂And R has the same definition as above;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, m1 and m2 represent an integer of 1 to 3;

n represents an integer of 0 to 12 (wherein, when n is 0, B is a single bond).

< P7> in any one of the above < P1> to < P3>, the component (a) may have any one photosensitive side chain selected from the group consisting of the following formulae (11) to (13).

Wherein A, X, l, m and R have the same meanings as defined above.

< P8> in any of the above < P1> to < P4>, the component (a) may have a photosensitive side chain represented by the following formula (14) or (15).

In the formula, A, Y₁X, l, m1 and m2 have the same definitions as above.

< P9> in any of the above < P1> to < P4>, the component (a) may have a photosensitive side chain represented by the following formula (16) or (17).

Wherein A, X, l and m have the same meanings as defined above.

< P10> in any of the above < P1> to < P4>, the component (a) may have a photosensitive side chain represented by the following formula (18) or (19).

In the formula, A, B, Y₁Q1, q2, m1, and m2 have the same definitions as above.

< P11> in any one of < P1> to < P4>, the component (a) may have a photosensitive side chain represented by the following formula (20).

In the formula, A, Y₁X, l and m have the same definitions as above.

< P12> in any one of the above < P1> to < P10>, the component (a) may have any one liquid crystalline side chain selected from the group consisting of the following formulae (21) to (31).

Wherein A, B, q1 and q2 have the same meanings as defined above;

l represents an integer of 1 to 12, m represents an integer of 0 to 2, wherein in the formulae (25) to (26), the sum of all m is 2 or more, in the formulae (27) to (28), the sum of all m is 1 or more, and m1, m2 and m3 each independently represents an integer of 1 to 3;

Z₁、Z₂represents a single bond, -CO-, -CH₂O-、-CH＝N-、-CF₂-。

< P13> A substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which is produced by any one of the above < P1> to < P12 >.

< P14> A transverse electric field driven liquid crystal display element having the substrate < P13 >.

< P15> a method for manufacturing a liquid crystal display element of a transverse electric field drive type, the method comprising the steps of:

preparing the substrate < P13> (the 1 st substrate);

the processes [ I ' ], [ II ' ] and [ III ' ] are:

[ III '] heating the coating film obtained in [ II' ].

< P16> a transverse electric field driven type liquid crystal display element produced by the above < P15 >.

< P17> A composition for producing a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer and contains a good solvent having a boiling point of 180 ℃ or higher in an amount of 10 mass% or more per 100 parts by mass of the good solvent,

< P18> in the above < P17>, the specific good solvent in the component (B) may be 1 or more selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), and Propylene Glycol Monomethyl Ether (PGME).

< P19> in the above < P17> or < P18>, the specific good solvent in the component (B) may be N-ethyl-2-pyrrolidone (NEP).

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which has excellent afterimage characteristics and is provided with an alignment control capability at high efficiency, and a transverse electric field driven liquid crystal display element having the substrate.

The liquid crystal display element of the transverse electric field type manufactured by the method of the present invention is efficiently provided with an alignment control capability, and therefore, even if continuously driven for a long time, the display characteristics are not impaired.

Further, the liquid crystal aligning agent of the present invention can provide a liquid crystal alignment film having high linearity at the end of the liquid crystal alignment film and small protrusion at the end of the liquid crystal alignment film.

Drawings

FIG. 1 is a view schematically illustrating an example of an anisotropy introduction treatment in a method for producing a liquid crystal alignment film used in the present invention, in which a crosslinkable organic group is used for a photosensitive side chain and the introduced anisotropy is small.

FIG. 2 is a view schematically illustrating an example of the anisotropy introduction treatment in the method for producing a liquid crystal alignment film used in the present invention, when a crosslinkable organic group is used for a photosensitive side chain and the introduced anisotropy is large.

Fig. 3 is a diagram schematically illustrating an example of the anisotropy introduction process in the method for producing a liquid crystal alignment film used in the present invention, in which an organic group that undergoes fries rearrangement or isomerization is used for a photosensitive side chain, and the introduced anisotropy is small.

Fig. 4 is a diagram schematically illustrating an example of the anisotropy introduction process in the method for producing a liquid crystal alignment film used in the present invention, and is a diagram when an organic group that undergoes fries rearrangement or isomerization is used for a photosensitive side chain and the introduced anisotropy is large.

Fig. 5 is a schematic view of an example of a coating film image of an optical microscope used for evaluating the linearity of the end portion of the liquid crystal alignment film.

Fig. 6 is a schematic view of an example of a coating film image of an optical microscope used for evaluating the end protrusion of the liquid crystal alignment film.

Detailed Description

The present inventors have conducted extensive studies and, as a result, have obtained the following findings, thereby completing the present invention.

The polymer composition used in the production method of the present invention has a photosensitive side chain type polymer capable of exhibiting liquid crystallinity (hereinafter also simply referred to as a side chain type polymer), and a coating film obtained using the polymer composition is a film having a photosensitive side chain type polymer capable of exhibiting liquid crystallinity. The coating film is subjected to an alignment treatment by polarized light irradiation without being subjected to a brushing treatment. After the polarized light irradiation, the side chain polymer film is heated to form a coating film (hereinafter, also referred to as a liquid crystal alignment film) to which an alignment control ability is imparted. At this time, the minute anisotropy exhibited by the polarized light irradiation becomes a driving force, and the liquid crystalline side chain polymer itself is effectively reoriented by self-assembly. As a result, efficient alignment treatment can be achieved as a liquid crystal alignment film, and a liquid crystal alignment film to which high alignment controllability is imparted can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.

< method for producing substrate having liquid crystal alignment film > and < method for producing liquid crystal display element >

The method for manufacturing a substrate having a liquid crystal alignment film according to the present invention includes the steps of:

[I] a step of forming a coating film by applying a polymer composition onto a substrate having a conductive film for driving a transverse electric field, the polymer composition comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer, wherein the good solvent has a boiling point of 180 ℃ or higher in an amount of 10 mass% or more per 100 parts by mass of the good solvent on average, the good solvent contains 1 or more specific good solvents selected from solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or the poor solvent contains propylene glycol monobutyl ether;

and [ III ] a step of heating the coating film obtained in [ II ].

Through the above steps, a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which an alignment control capability is imparted can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

In addition to the substrate (1 st substrate) obtained above, the 2 nd substrate is prepared, whereby the in-plane electric field driven liquid crystal display element can be obtained.

The 2 nd substrate is obtained by using the above-mentioned steps [ I ] to [ III ] (since a substrate having no conductive film for driving a transverse electric field is used, it may be abbreviated as the steps [ I '] to [ III' ] in the present application for convenience sake) in place of the substrate having the conductive film for driving a transverse electric field, and the 2 nd substrate having the liquid crystal alignment film to which an alignment control capability is imparted can be obtained.

The method for manufacturing the transverse electric field driven liquid crystal display element comprises the following steps:

[ IV ] a step of disposing the 1 st substrate and the 2 nd substrate obtained as described above in such a manner that the liquid crystal alignment films of the 1 st substrate and the 2 nd substrate face each other with the liquid crystal interposed therebetween to obtain a liquid crystal display element. This makes it possible to obtain a transverse electric field driven liquid crystal display element.

The following describes the respective steps of [ I ] to [ III ] and [ IV ] included in the production method of the present invention.

< Process [ I ] >

In the step [ I ], a polymer composition is applied to a substrate having a conductive film for driving a transverse electric field to form a coating film, the polymer composition comprising: a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and an organic solvent.

< substrate >

The substrate is not particularly limited, and when the liquid crystal display element to be manufactured is of a transmissive type, a substrate having high transparency is preferably used. In this case, there is no particular limitation, and a glass substrate, an acrylic substrate, a plastic substrate such as a polycarbonate substrate, or the like can be used.

In addition, an opaque substrate such as a silicon wafer may be used in consideration of application to a reflective liquid crystal display element.

< conductive film for driving transverse electric field >

The substrate has a conductive film for driving a transverse electric field.

When the liquid crystal display element is a transmissive conductive film, examples of the conductive film include, but are not limited to, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and the like.

In the case of a reflective liquid crystal display element, examples of the conductive film include, but are not limited to, materials that reflect light, such as aluminum.

As a method for forming a conductive film on a substrate, a conventionally known method can be used.

< Polymer composition >

A polymer composition is applied to a substrate having a conductive film for driving a transverse electric field, and particularly, a polymer composition is applied to a conductive film.

The polymer composition used in the production method of the present invention contains: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range; and (B) an organic solvent.

[ side chain type Polymer (A) ]

(A) The component (A) is a photosensitive side chain type polymer which exhibits liquid crystallinity in a specific temperature range.

(A) The side chain type polymer may be reacted with light having a wavelength of 250 to 400nm and exhibit liquid crystallinity at a temperature of 100 to 300 ℃.

(A) The side chain type polymer preferably has a photosensitive side chain which reacts with light having a wavelength in the range of 250nm to 400 nm.

(A) The side chain type polymer preferably has a mesogen group because it exhibits liquid crystallinity at a temperature of 100 to 300 ℃.

(A) The side chain type polymer has a main chain to which a photosensitive side chain is bonded, and is capable of undergoing a crosslinking reaction, an isomerization reaction, or a photo-fries rearrangement in response to light. The side chain structure having photosensitivity is not particularly limited, and is preferably a structure in which a crosslinking reaction or a photo-fries rearrangement occurs in response to light, and more preferably a structure in which a crosslinking reaction occurs. At this time, the achieved orientation controllability can be stably maintained for a long period of time even if exposed to external stress such as heat. The structure of the photosensitive side chain type polymer film capable of exhibiting liquid crystallinity is not particularly limited as long as it satisfies such characteristics, and a mesogen component having a rigid side chain structure is preferable. In this case, when the side chain polymer is formed into a liquid crystal alignment film, stable liquid crystal alignment can be obtained.

The structure of the polymer can be, for example, as follows: a main chain and a side chain bonded to the main chain, wherein the side chain has a liquid crystal component such as biphenyl, terphenyl, phenylcyclohexyl, phenylbenzoate, azophenyl and the like, and a photosensitive group which is bonded to the tip portion and which is subjected to a crosslinking reaction or an isomerization reaction by induced light; has a main chain and a side chain bonded thereto, the side chain having a benzoate group which is both a mesogen component and is subjected to a photo-Fries rearrangement reaction.

More specific examples of the structure of the photosensitive side chain type polymer film capable of exhibiting liquid crystallinity preferably include a structure having a main chain composed of at least 1 kind selected from the group consisting of a radical polymerizable group such as hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl, maleimide, norbornene and siloxane, and a side chain containing at least 1 kind selected from the group consisting of formulas (1) to (6).

Y₁represents a ring selected from a 1-valent 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 a group in which 2 to 6 identical or different rings selected from these substituents are bonded via a bonding group B, and hydrogen atoms bonded to these are each independently optionally substituted by-COOR₀(in the formula, R₀Hydrogen atom or C1-5 alkyl group), -NO₂、-CN、-CH＝C(CN)₂、-CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms;

one of q1 and q2 is 1 and the other is 0;

q3 is 0 or 1;

l1 is 0 or 1;

l2 is an integer of 0 to 2;

when l1 and l2 are both 0, A represents a single bond when T is a single bond;

when l1 is 1, B represents a single bond when T is a single bond;

The side chain may be any one photosensitive side chain selected from the group consisting of the following formulas (7) to (10).

In the formula, A, B, D, Y₁、X、Y₂And R has the same definition as above;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, m1 and m2 represent an integer of 1 to 3;

n represents an integer of 0 to 12 (wherein, when n is 0, B is a single bond).

The side chain may be any one photosensitive side chain selected from the group consisting of the following formulas (11) to (13).

Wherein A, X, l, m1 and R have the same meanings as defined above.

The side chain may be a photosensitive side chain represented by the following formula (14) or (15).

In the formula, A, Y₁L, m1 and m2 have the same definitions as above.

The side chain may be a photosensitive side chain represented by the following formula (16) or (17).

Wherein A, X, l and m have the same meanings as defined above.

The side chain may be a photosensitive side chain represented by the following formula (18) or (19).

In the formula, A, B, Y₁Q1, q2, m1 andm2 has the same definition as above.

The side chain may be a photosensitive side chain represented by the following formula (20).

In the formula, A, Y₁X, l and m have the same definitions as above.

The side chain polymer (a) may have any liquid crystalline side chain selected from the group consisting of the following formulas (21) to (31).

Wherein A, B, q1 and q2 have the same meanings as defined above;

R₂represents a hydrogen atom, -NO₂-CN, halogen radicalA group consisting of a 1-valent benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a nitrogen-containing heterocycle, an alicyclic hydrocarbon having 5 to 8 carbon atoms, and an alkyl group or an alkoxy group;

Z₁、Z₂represents a single bond, -CO-, -CH₂O-、-CH＝N-、-CF₂-。

[ production method of photosensitive side-chain type Polymer ]

The photosensitive side chain polymer capable of exhibiting liquid crystallinity can be obtained by polymerizing a photoreactive side chain monomer having the photosensitive side chain and a liquid crystalline side chain monomer.

[ photoreactive side chain monomer ]

Photoreactive side chain monomers refer to: in the case of forming a polymer, a monomer of the polymer having a photosensitive side chain at a side chain site of the polymer can be formed.

The photoreactive group in the side chain is preferably represented by the following structure or a derivative thereof.

More specific examples of the photoreactive side chain monomer are preferably a structure having a polymerizable group composed of at least 1 selected from the group consisting of a radical polymerizable group such as hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl, maleimide, norbornene and siloxane, and a photosensitive side chain containing at least 1 of the above formulae (1) to (6), preferably, for example, a photosensitive side chain containing at least 1 of the above formulae (7) to (10), a photosensitive side chain containing at least 1 of the above formulae (11) to (13), a photosensitive side chain represented by the above formulae (14) or (15), a photosensitive side chain represented by the above formulae (16) or (17), a photosensitive side chain, A photosensitive side chain represented by the above formula (18) or (19), or a photosensitive side chain represented by the above formula (20).

In the present application, as photoreactive and/or liquid crystalline side chain monomers, novel compounds (1) to (11) represented by the following formulae (1) to (11) are provided; and compounds (12) to (17) represented by the following formulae (12) to (17).

Wherein R represents a hydrogen atom or a methyl group; s represents an alkylene group having 2 to 10 carbon atoms; r¹⁰Represents Br or CN; s represents an alkylene group having 2 to 10 carbon atoms; u represents 0 or 1; and Py represents 2-pyridyl, 3-pyridyl or 4-pyridyl. In addition, v represents 1 or 2.

[ liquid Crystal side chain monomer ]

The liquid crystalline side chain monomer means: a polymer derived from the monomer exhibits liquid crystallinity, and the polymer is a monomer capable of forming a mesogen group at a side chain position.

The mesogen group of the side chain may be a group having a mesogen structure alone, such as biphenyl or phenyl benzoate, or a group having a mesogen structure in which side chains are hydrogen-bonded to each other, such as benzoic acid. The mesogen group of the side chain is preferably of the following structure.

More specific examples of the liquid crystalline side chain monomer are preferably those having a structure having a polymerizable group composed of at least 1 selected from the group consisting of a hydrocarbon, a (meth) acrylate, an itaconate, a fumarate, a maleate, α -methylene- γ -butyrolactone, styrene, a vinyl group, a maleimide, norbornene and other radical polymerizable groups, and a siloxane, and a side chain containing at least 1 of the above formulas (21) to (31).

(A) The side chain type polymer can be obtained by polymerization of the photoreactive side chain monomer exhibiting liquid crystallinity. The side chain monomer is obtained by copolymerization of a photoreactive side chain monomer that does not exhibit liquid crystallinity and a liquid crystalline side chain monomer, or copolymerization of a photoreactive side chain monomer that exhibits liquid crystallinity and a liquid crystalline side chain monomer. Further, the monomer may be copolymerized with another monomer within a range not impairing the liquid crystal property expressing ability.

Examples of the other monomers include industrially available monomers capable of radical polymerization.

Specific examples of the other monomer include unsaturated carboxylic acids, acrylate compounds, methacrylate compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, and the like.

Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid.

Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2, 2-trifluoroethyl acrylate, t-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-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecanyl acrylate, and 8-ethyl-8-tricyclodecanyl acrylate.

Examples of the methacrylate compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2, 2-trifluoroethyl methacrylate, t-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-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecanyl methacrylate, and mixtures thereof, And 8-ethyl-8-tricyclodecyl methacrylate and the like. (meth) 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 can also be used.

Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, and bromostyrene.

Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

The method for producing the side chain polymer of the present embodiment is not particularly limited, and an industrially applicable general method can be used. Specifically, the polymer can be produced by cationic polymerization, radical polymerization, or anionic polymerization of a vinyl group using a liquid crystalline side chain monomer or a photoreactive side chain monomer. Among these, radical polymerization is particularly preferable from the viewpoint of ease of reaction control and the like.

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

The radical thermal polymerization initiator is a compound that generates radicals by heating to a temperature above 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.), hydrogen peroxides (hydrogen peroxide, t-butyl peroxide, cumene peroxide, etc.), dialkyl peroxides (di-t-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals (e.g., dibutylperoxycyclohexane), alkyl peroxyesters (e.g., t-butyl peroxyneodecanoate, t-butyl peroxypivalate, and t-amyl 2-ethylcyclohexanoate), persulfates (e.g., potassium persulfate, sodium persulfate, and ammonium persulfate), and azo compounds (e.g., azobisisobutyronitrile and 2, 2' -bis (2-hydroxyethyl) azobisisobutyronitrile). Such radical thermal polymerization initiators may be used in 1 kind alone, or 2 or more kinds may be used in combination.

The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by irradiation with light. Examples of such a radical photopolymerization initiator include benzophenone, Michler's ketone, 4 ' -bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropyl xanthone, 2, 4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-4 ' -isopropylphenylacetone, 1-hydroxycyclohexylphenylketone, isopropylbenzoin ether, isobutylbenzoin ether, 2-diethoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, and, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4 ' -bis (tert-butylperoxycarbonyl) benzophenone, 3,4,4 ' -tris (tert-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-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 4-dimethylaminobenzoate, 4-dimethylaminob, 2- (2 ' -methoxystyryl) -4, 6-bis (trichloromethyl) s-triazine, 2- (4 ' -pentyloxystyryl) -4, 6-bis (trichloromethyl) s-triazine, 4- [ p-N, N-bis (ethoxycarbonylmethyl) ] -2, 6-bis (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) benzothiazole, 2-mercaptobenzothiazole, 3 ' -carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4,4 ', 5,5 ' -tetraphenyl-1, 2 ' -biimidazole, 2 ' -bis (2-chlorophenyl) -4,4 ', 5,5 ' -tetrakis (4-ethoxycarbonylphenyl) -1,2 ' -biimidazole, 2 ' -bis (2, 4-dichlorophenyl) -4,4 ', 5,5 ' -tetraphenyl-1, 2 ' -biimidazole, 2 ' -bis (2, 4-dibromophenyl) -4,4 ', 5,5 ' -tetraphenyl-1, 2 ' -biimidazole, 2 ' -bis (2,4, 6-trichlorophenyl) -4,4 ', 5,5 ' -tetraphenyl-1, 2 ' -biimidazole, 3- (2-methyl-2-dimethylaminopropionyl) carbazole, 3, 6-bis (2-methyl-2-morpholinopropionyl) -9-n-dodecylcarbazole, 1-hydroxycyclohexylphenylketone, bis (5-2, 4-cyclopentadien-1-yl) -bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 3 ', 4,4 ' -tetrakis (tert-butylperoxycarbonyl) benzophenone, 3 ', 4,4 ' -tetrakis (tert-hexylperoxycarbonyl) benzophenone, 3 ' -bis (methoxycarbonyl) -4,4 ' -bis (tert-butylperoxycarbonyl) benzophenone, 3,4 ' -bis (methoxycarbonyl) -4,3 ' -bis (t-butylperoxycarbonyl) benzophenone, 4 ' -bis (methoxycarbonyl) -3,3 ' -bis (t-butylperoxycarbonyl) benzophenone, 2- (3-methyl-3H-benzothiazol-2-ylidene) -1-naphthalen-2-yl-ethanone, or 2- (3-methyl-1, 3-benzothiazol-2 (3H) -ylidene) -1- (2-benzoyl) ethanone, and the like. These compounds may be used alone or in combination of two or more.

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

The organic solvent used for the polymerization reaction of the photosensitive side chain type polymer capable of exhibiting liquid crystallinity is not particularly limited as long as the polymer to be produced is soluble in the organic solvent. Specific examples thereof are listed below.

Examples thereof include: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, gamma-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentyl ketone, methylnonyl ketone, methylethyl ketone, methylisoamyl ketone, methylisopropyl ketone, methylcellosolve, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monomethyl ether, propylene glycol, Diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate 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, diisobutyl ketone, 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, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl propionate, ethyl propionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionate, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, and the like.

These organic solvents may be used alone or in combination. Further, the solvent that does not dissolve the produced polymer may be mixed with the organic solvent and used as long as the produced polymer is not precipitated.

In addition, in radical polymerization, oxygen in an organic solvent may cause inhibition of the polymerization reaction, and therefore, it is preferable to use the organic solvent after degassing as much as possible.

The polymerization temperature in the radical polymerization can be selected from any temperature of 30 to 150 ℃, and preferably from 50 to 100 ℃. The reaction may be carried out at any concentration, and when the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and when the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring becomes difficult, and therefore the monomer concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction is carried out at a high concentration in the initial stage, and an organic solvent may be added thereafter.

In the radical polymerization reaction, when the ratio of the radical polymerization initiator to the monomer is large, the molecular weight of the resulting polymer becomes small, and when the ratio of the radical polymerization initiator to the monomer is small, the molecular weight of the resulting polymer becomes large, so the ratio of the radical polymerization initiator to the polymerized monomer is preferably 0.1 to 10 mol%. In addition, various monomer components, solvents, initiators, and the like may be added during the polymerization.

[ recovery of Polymer ]

When the polymer produced is recovered from the reaction solution of the photosensitive side chain type polymer capable of exhibiting liquid crystallinity obtained by the above reaction, the reaction solution may be charged into a poor solvent to precipitate the polymer. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by being put into the poor solvent may be recovered by filtration and then dried at normal temperature or under reduced pressure or dried by heating. Further, when the operation of re-dissolving the polymer recovered by precipitation in the organic solvent and re-precipitating and recovering is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons and the like, and when 3 or more kinds of poor solvents selected from these are used, the purification efficiency is further improved, which is preferable.

The molecular weight of the side chain polymer (a) of the present invention is preferably 2000 to 1000000, more preferably 5000 to 100000, in terms of the strength of the obtained coating film, the workability in forming the coating film, and the uniformity of the coating film, as measured by Gel Permeation Chromatography (GPC).

[ preparation of Polymer composition ]

The polymer composition used in the present invention is preferably prepared in the form of 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 in the form of a solution in which a resin component for forming a resin coating is dissolved in an organic solvent. Here, the resin component is a resin component containing the photosensitive side chain type polymer capable of exhibiting liquid crystallinity described above. In this case, the content of the resin component is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 3 to 10% by mass.

In the polymer composition of the present embodiment, the resin component may be all of the above-mentioned photosensitive side chain type polymers capable of expressing liquid crystallinity, and other polymers may be mixed in the range not impairing the liquid crystal expression ability and the photosensitive property. In this case, the content of the other polymer in the resin component is 0.5 to 80% by mass, preferably 1 to 50% by mass.

Examples of such other polymers include polymers that include poly (meth) acrylates, polyamic acids, polyimides, and the like and are not photosensitive side chain type polymers capable of exhibiting liquid crystallinity.

< organic solvent (B) >

The organic solvent used in the polymer composition used in the present invention (i.e., the organic solvent as the (B) component) means: the organic solvent has both an organic solvent (also referred to herein as a "good solvent") for dissolving the side chain polymer as the component (A) and a solvent (also referred to herein as a "poor solvent" for the side chain polymer as the component (A)) for improving film thickness uniformity and surface smoothness, and has a good solvent having a boiling point of 180 ℃ or higher of 10 mass% or more among 100 parts by mass of the good solvent on average. The good solvent in the organic solvent as component (B) includes 1 or more kinds of specific good solvents (referred to herein as "specific good solvents") selected from solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or the poor solvent in the organic solvent as component (B) includes propylene glycol monobutyl ether which is a specific poor solvent (referred to herein as "specific poor solvent").

In other words, the organic solvent as component (B) contains both a good solvent and a poor solvent of the side chain type polymer as component (a), and the good solvent contains 10 mass% or more of the good solvent having a boiling point of 180 ℃ or more on average in 100 parts by mass, and in this case, the good solvent contains the specific good solvent, or the poor solvent contains the specific poor solvent, or the good solvent contains the specific good solvent and the poor solvent contains the specific poor solvent. That is, in the present invention, the organic solvent as the component (B) contains 10 mass% or more of a good solvent having a boiling point of 180 ℃ or higher in an average of 100 parts by mass of the good solvent, and contains at least one of a specific good solvent and a specific poor solvent.

In the present invention, it is preferable that the good solvent contains 10 to 100 mass% of the good solvent having a boiling point of 180 ℃ or higher in an average of 100 parts by mass of the good solvent so that the good solvent remains until the end of the heating and drying step. Among them, the amount is preferably 20 to 100% by mass, and more preferably 30 to 100% by mass.

The "good solvent having a boiling point of 180 ℃ or higher" can be appropriately selected by referring to a publicly known document such as the aforementioned "solvent handbook" (lecture).

In the present invention, in order to improve the solubility of the polymer, the good solvent is preferably 5 to 90% by mass of the entire organic solvent contained in the liquid crystal aligning agent. Among them, it is preferably 10 to 80% by mass. More preferably 30 to 70 mass%.

Specific good solvent (a) >

In the present invention, the specific good solvent that can be contained in the organic solvent as component (B) is a good solvent having excellent solubility of polyamic acid and soluble polyimide, and has a lower surface tension and a boiling point in a specific range as compared with N-methyl-2-pyrrolidone (NMP) and γ -butyrolactone (γ BL) that are generally used. More specifically, as described above, the boiling point is 100 to 230 ℃ and the surface tension is less than 41.0 dyn/cm.

By using a specific good solvent for the liquid crystal aligning agent, the wetting diffusibility of the coating solution to the substrate is higher than that of a liquid crystal aligning agent not using a specific good solvent, and a liquid crystal alignment film having excellent coating film uniformity can be obtained without using a large amount of a poor solvent having low resin solubility. In addition, since the wetting and diffusing properties of the coating solution (liquid crystal alignment agent) are high, the linearity of the edge portion is high when the liquid crystal alignment film is formed.

As described above, the boiling point of the specific good solvent in the present invention is preferably 100 to 230 ℃, more preferably 110 to 230 ℃, and still more preferably 180 to 220 ℃. The surface tension of the specific good solvent in the present invention is less than 41.0dyn/cm, more preferably less than 39.0dyn/cm, and still more preferably 36.0dyn/cm or less. According to a preferred embodiment of the present invention, the specific good solvent preferably has a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, more preferably has a boiling point of 110 to 230 ℃ and a surface tension of less than 39.0dyn/cm, and still more preferably has a boiling point of 180 to 220 ℃ and a surface tension of 36.0dyn/cm or less. The specific good solvent in the present invention is 1 or more selected from organic solvents satisfying the conditions of the boiling point and the surface tension.

Here, a specific good solvent satisfies the boiling point and the surface tension, and can be appropriately selected by referring to the boiling point of the organic solvent and the known literature value of the surface tension.

For example, literature values of the boiling point and surface tension of N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), Propylene Glycol Monomethyl Ether (PGME), and further N-methyl-2-pyrrolidone (NMP) and γ -butyrolactone (γ BL) which are examples of conventional use are as follows.

[ Table 1]

(Exit: "solvent handbook" solvent ハンドブック "(1982) lecture)

According to a preferred embodiment of the present invention, the specific good solvent in the present invention includes the following solvents and the like: which are N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), Propylene Glycol Monomethyl Ether (PGME), and solvents represented by the following formulae [ D-1] to [ D-3], and satisfy the aforementioned conditions of boiling point and surface tension.

(formula [ D-1]]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms; formula [ D-2]In (D)²Represents an alkyl group having 1 to 3 carbon atoms; formula [ D-3]In (D)³Represents an alkyl group having 1 to 4 carbon atoms).

According to a more preferred embodiment of the present invention, the specific good solvent in the present invention is 1 or more selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), and Propylene Glycol Monomethyl Ether (PGME),

further preferably selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), 1, 3-Dimethylimidazolidinone (DMI),

n-ethyl-2-pyrrolidone (NEP) is particularly preferred.

In the present invention, when the good solvent includes the specific good solvent and the good solvent having a boiling point of 180 ℃ or higher is contained in addition to the specific good solvent, the specific good solvent is preferably 10 to 90% by mass of the whole good solvent in the organic solvent to be used. More preferably 30 to 80 mass%.

In the present invention, when the good solvent includes the specific good solvent, and the specific good solvent is a good solvent having a boiling point of 180 ℃ or higher, the specific good solvent is preferably 10 to 100% by mass of the entire good solvent in the organic solvent to be used. More preferably 30 to 100 mass%.

In the present invention, when the good solvent includes the specific good solvent and further includes a good solvent having a boiling point of 180 ℃ or higher in addition to the specific good solvent, the specific good solvent is preferably 5 to 80% by mass of the entire organic solvent included in the liquid crystal aligning agent. Among them, it is preferably 10 to 70% by mass. More preferably 20 to 60% by mass.

In the present invention, when the good solvent includes the specific good solvent, and the specific good solvent is a good solvent having a boiling point of 180 ℃ or higher, the specific good solvent is preferably 5 to 90% by mass of the entire organic solvent included in the liquid crystal aligning agent. Among them, it is preferably 10 to 80% by mass. More preferably 20 to 70 mass%.

Specific poor solvent

In the present invention, a specific poor solvent that can be contained in the organic solvent as the component (B) is propylene glycol monobutyl ether.

In the present invention, when the poor solvent includes the specific poor solvent, the specific poor solvent is preferably 30 to 100% by mass of the total poor solvent in the organic solvent to be used. More preferably 50 to 100 mass%.

In the present invention, when the poor solvent includes propylene glycol monobutyl ether as a specific poor solvent, the wetting and diffusing properties of the coating solution on the substrate are improved, and therefore, the propylene glycol monobutyl ether is preferably 5 to 70% by mass of the entire organic solvent included in the liquid crystal aligning agent. Among them, it is preferably 10 to 70% by mass. More preferably 10 to 60 mass%.

The effect of the present invention can be obtained as the amount of the specific good solvent or the specific poor solvent of the present invention is larger in the whole organic solvent in the liquid crystal alignment agent, and the liquid crystal alignment film having high linearity of the end portion of the liquid crystal alignment film and small protrusion of the end portion of the liquid crystal alignment film can be obtained.

The effect is increased by containing both the specific good solvent and the specific poor solvent of the present invention.

According to a preferred embodiment of the present invention, among the organic solvents to be used, it is preferable that 30 to 100% of the good solvents are specific good solvents having a boiling point of 180 ℃ or higher and/or 30 to 100% of the poor solvents are specific poor solvents.

Other organic solvents < < c > > >)

As the organic solvent used for the polymer composition used in the present invention, other organic solvents can be used in addition to the above-described specific good solvent and specific poor solvent. The solvent is not particularly limited as long as it is an organic solvent that dissolves the resin component. Specific examples thereof are listed below.

Examples thereof include: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, γ -butyrolactone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, 1, 3-dimethylimidazolidinone, ethylpentyl ketone, methylnonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4-methyl-2-pentanone, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl carbonate, methyl glycol dimethyl ether, methyl 4-hydroxy-4-methyl-2-pentanone, methyl ethyl ketone, methyl ethyl, Propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol t-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate 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, and the like. They may be used alone or in combination.

The other organic solvent that can be used in the liquid crystal aligning agent of the present invention can be selected from organic solvents (other good solvents) that dissolve a specific polymer. Specific examples of such good solvents are listed below, but the solvents are not limited to these examples.

Examples thereof include N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ -butyrolactone, 1, 3-dimethylimidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and solvents represented by the above formulae [ D-1] to [ D-3 ].

Among these other good solvents, N-methyl-2-pyrrolidone and γ -butyrolactone are preferably used. When the solubility of the specific polymer in the solvent is high, it is also preferable to use solvents represented by the above formulae [ D-1] to [ D-3 ].

As other organic solvents, the following solvents can be mentioned as specific examples of solvents (other poor solvents) for improving the uniformity of film thickness and surface smoothness.

Examples thereof include isopropyl alcohol, methoxymethyl amyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol acetate, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate 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, methyl cellosolve, ethyl cellosolve, butyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monobutyl ether, 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 acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1-hexanol ether, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl 3-methoxypropion, And solvents having low surface tension such as propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate.

The other poor solvent is preferably 1 to 60% by mass of the entire organic solvent contained in the liquid crystal aligning agent. Among them, it is preferably 1 to 50% by mass. More preferably 5 to 40 mass%.

The polymer composition used in the present invention may contain components other than the above-mentioned (a) and (B). Examples thereof include, but are not limited to, compounds that improve the adhesion between the liquid crystal alignment film and the substrate when the polymer composition is applied.

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, and a nonionic surfactant.

More specifically, for example, Eftop (registered trademark) 301, EF303, EF352 (manufactured by Tohkem products Corporation); megafac (registered trademark) F171, F173, R-30 (manufactured by DIC CORPORATION); fluorad FC430, FC431 (manufactured by Sumitomo 3M Limited); asahiguard (registered trademark) AG710 (manufactured by Asahi glass Co., Ltd.); surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106(AGC SEIMI CHEMICAL CO., LTD., manufactured by Ltd.), and the like. The proportion of the surfactant to be used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the resin component contained in the polymer composition.

Specific examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include functional silane-containing compounds described below.

Examples thereof include 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-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriamine, N-trimethoxysilylpropyltriamine, 10-trimethoxysilyl-1, 4, 7-triazacyclodecane, 10-triethoxysilyl-1, 4, 7-triazacyclodecane, 9-trimethoxysilyl-3, 6-diaza-nonyl acetate, 9-triethoxysilyl-3, 6-diaza-nonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, n-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc.

Further, in order to improve the adhesion between the substrate and the liquid crystal alignment film and to prevent the deterioration of electrical characteristics due to a backlight when constituting the liquid crystal display element, an additive such as a phenolplast-based or epoxy-containing compound may be contained in the polymer composition. Specific examples of the phenolic plastic additive are shown below, but the additive is not limited to this structure.

Specific examples of the epoxy group-containing compound 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, glycerol diglycidyl ether, 2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2, 4-hexanediol, N ', -tetraglycidyl m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N ', -tetraglycidyl-4, 4 ' -diaminodiphenylmethane, and the like.

When a compound for improving the adhesion between the liquid crystal alignment film and the substrate is used, the amount thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the resin component contained in the polymer composition. When the amount is less than 0.1 part by mass, the effect of improving the adhesion cannot be expected, and when it is more than 30 parts by mass, the alignment property of the liquid crystal may be deteriorated.

As additives, photosensitizers may also be used. Preference is given to colourless sensitizers and triplet sensitizers.

As the photosensitizer, there are aromatic nitro compounds, coumarins (7-diethylamino-4-methylcoumarin, 7-hydroxy-4-methylcoumarin), coumarins, carbonyldicoumarin, aromatic 2-hydroxyketones, and amino-substituted aromatic 2-hydroxyketones (2-hydroxybenzophenone, mono-p- (dimethylamino) -2-hydroxybenzophenone) or di-p- (dimethylamino) -2-hydroxybenzophenone), acetophenone, anthraquinone, xanthone, thioxanthone, benzanthrone, thiazoline (2-benzoylmethylene-3-methyl- β -naphthothiazoline, 2- (. beta. -naphthoylmethylene) -3-methylbenzothiazoline, 2- (. alpha. -naphthoylmethylene) -3-methylbenzothiazoline, water-soluble salts thereof, and water-soluble salts thereof, 2- (4-benzimidomethylene) -3-methylbenzothiazoline, 2- (beta-naphthoylmethylene) -3-methyl-beta-naphthothiazoline, 2- (4-benzimidomethylene) -3-methyl-beta-naphthothiazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-beta-naphthothiazoline), oxazoline (2-benzoylmethylene-3-methyl-beta-naphthooxazoline, 2- (beta-naphthoylmethylene) -3-methylbenzoxazolin, 2- (alpha-naphthoylmethylene) -3-methylbenzoxazolin, 2- (4-benzimidomethylene) -3-methylbenzoxazolin, oxazoline, 2- (beta-naphthoylmethylene) -3-methyl-beta-naphthooxazoline, 2- (4-benziylmethylene) -3-methyl-beta-naphthooxazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-beta-naphthooxazoline), benzothiazole, nitroaniline (m-or p-nitroaniline, 2,4, 6-trinitroaniline) or nitroacenaphthylene (5-nitroacenaphthylene), (2- [ (m-hydroxy-p-methoxy) styryl ] benzothiazole, benzoin alkyl ether, N-alkylated phthalein, acetophenone ketal (2, 2-dimethoxyacetophenone), naphthalene, anthracene (2-naphthalenemethanol, 2-naphthalenecarboxylic acid, 9-anthracenemethanol and 9-anthracenecarboxylic acid), Benzopyran, azoindolizine, melolonoumarin, and the like.

Aromatic 2-hydroxyketones (benzophenone), coumarins, carbonyldicumarol, acetophenone, anthraquinone, xanthone, thioxanthone and acetophenone ketals are preferred.

In addition to the above-mentioned substances, a dielectric or conductive substance may be added to the polymer composition for the purpose of changing electrical characteristics such as dielectric constant and conductivity of the liquid crystal alignment film, and a crosslinkable compound may be added for the purpose of improving hardness and density of the film when the liquid crystal alignment film is produced, within a range not to impair the effects of the present invention.

The method for applying the polymer composition to a substrate having a conductive film for driving a transverse electric field is not particularly limited.

As for the coating method, a method using screen printing, offset printing, flexographic printing, inkjet method, or the like is generally industrially used. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spin coating method (spin coating method), a spray coating method, and the like, and they can be used according to the purpose.

The polymer composition is applied to a substrate having a conductive film for driving a transverse electric field, and then the solvent is evaporated at 50 to 200 ℃, preferably 50 to 150 ℃ by a heating means such as a hot plate, a thermal cycle oven or an IR (infrared) oven, thereby obtaining a coating film. The drying temperature in this case is preferably lower than the liquid crystal phase appearance temperature of the side chain type polymer.

When the thickness of the coating film is too large, it is disadvantageous in terms of power consumption of the liquid crystal display element, and when the thickness of the coating film is too small, reliability of the liquid crystal display element may be lowered, and therefore, it is preferably 5nm to 300nm, more preferably 10nm to 150 nm.

Further, after the step [ I ] and before the next step [ II ], a step of cooling the substrate having the coating film formed thereon to room temperature may be provided.

< Process [ II ] >

In the step [ II ], the coating film obtained in the step [ I ] is irradiated with polarized ultraviolet rays. When polarized ultraviolet light is irradiated to the film surface of the coating film, the substrate is irradiated with the polarized ultraviolet light from a specific direction through a polarizing plate. As the ultraviolet ray to be used, ultraviolet rays having a wavelength in the range of 100nm to 400nm can be used. Preferably, the optimum wavelength is selected by means of a filter or the like according to the kind of the coating film to be used. Further, for example, ultraviolet rays having a wavelength in the range of 290 to 400nm can be selectively used so that the photocrosslinking reaction can be selectively induced. As the ultraviolet rays, light emitted from a high-pressure mercury lamp, for example, can be used.

The irradiation amount with respect to the polarized ultraviolet ray depends on the coating film to be used. The irradiation amount is preferably in the range of 1% to 70%, more preferably in the range of 1% to 50%, of the amount of polarized ultraviolet light that achieves the maximum value of Δ a (hereinafter also referred to as Δ Amax), which is the difference between the ultraviolet absorbance of the coating film in the direction parallel to the polarization direction of the polarized ultraviolet light and the ultraviolet absorbance of the coating film in the direction perpendicular to the polarization direction of the polarized ultraviolet light.

< Process [ III ] >

In the step [ III ], the coating film irradiated with the polarized ultraviolet ray in the step [ II ] is heated. The orientation control ability can be imparted to the coating film by heating.

Heating means such as a hot plate, a thermal cycle type oven, or an IR (infrared ray) type oven can be used for heating. The heating temperature may be determined in consideration of the temperature at which the coating film used exhibits liquid crystallinity.

The heating temperature is preferably within a temperature range at which the side chain polymer exhibits liquid crystallinity (hereinafter referred to as a liquid crystal display temperature). It can be predicted that: in the case of a film surface such as a coating film, the liquid crystal display temperature on the coating film surface is lower than that when a photosensitive side chain polymer exhibiting liquid crystallinity is observed as a whole. Therefore, the heating temperature is more preferably within the temperature range of the liquid crystal display temperature on the surface of the coating film. That is, the temperature range of the heating temperature after irradiation with polarized ultraviolet rays is preferably a temperature in a range having a lower limit of 10 ℃ lower than the lower limit of the temperature range of the liquid crystal display temperature of the side chain polymer used and an upper limit of 10 ℃ lower than the upper limit of the liquid crystal temperature range. When the heating temperature is lower than the above temperature range, the effect of increasing anisotropy by heat tends to be insufficient in the coating film, and when the heating temperature is too high as compared with the above temperature range, the state of the coating film tends to be close to an isotropic liquid state (isotropic phase), and in this case, it may be difficult to reorient the coating film in one direction by self-assembly.

The liquid crystal display temperature is: the surface of the side chain polymer or the coating film has a temperature not lower than the glass transition temperature (Tg) at which the phase transition from the solid phase to the liquid crystal phase occurs, and not higher than the homogeneous phase transition temperature (Tiso) at which the phase transition from the liquid crystal phase to the homogeneous phase (isotropic phase) occurs.

The thickness of the coating film formed after heating may be preferably 5nm to 300nm, more preferably 50nm to 150nm, for the same reason as described in the step [ I ].

By having the above steps, the production method of the present invention can efficiently introduce anisotropy into a coating film. Further, a substrate with a liquid crystal alignment film can be efficiently produced.

< Process [ IV ] >

The step IV is a step of preparing a transverse electric field driving type liquid crystal display element by disposing a substrate (1 st substrate) having a liquid crystal alignment film on the transverse electric field driving conductive film obtained in the step III and a substrate (2 nd substrate) having a liquid crystal alignment film without a conductive film obtained in the same manner as in the steps I 'to III' so as to face each other with the liquid crystal alignment films of both substrates facing each other through a liquid crystal, and preparing a liquid crystal cell by a known method. In the steps [ I '] to [ III' ], the steps can be performed in the same manner as the steps [ I ] to [ III ], except that a substrate having no conductive film for driving a lateral electric field is used in the step [ I ] instead of the substrate having the conductive film for driving a lateral electric field. The steps [ I ] to [ III ] are different from the steps [ I '] to [ III' ] only in the presence or absence of the conductive film, and therefore, the steps [ I '] to [ III' ] are omitted from description.

When an example of manufacturing a liquid crystal cell or a liquid crystal display element is described, the following method can be exemplified: a method of preparing the 1 st substrate and the 2 nd substrate, spreading spacers on the liquid crystal alignment film of one substrate, attaching the substrates to each other with the liquid crystal alignment film surface facing inward, injecting liquid crystal under reduced pressure, and sealing the substrates; or a method of dropping liquid crystal onto the liquid crystal alignment film surface on which the spacers are dispersed, and then attaching and sealing the substrate. In this case, it is preferable to use a substrate having an electrode with a comb-tooth structure for driving a transverse electric field as one substrate. The spacer diameter in this case is preferably 1 to 30 μm, more preferably 2 to 10 μm. The spacer diameter determines the distance between the pair of substrates for sandwiching 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, after a coating film is formed by applying the polymer composition onto a substrate, polarized ultraviolet rays are irradiated. Then, by heating, the anisotropy is efficiently introduced into the side chain type polymer film, and a substrate with a liquid crystal alignment film having a liquid crystal alignment controllability is manufactured.

The coating film used in the present invention realizes efficient introduction of anisotropy into the coating film by utilizing the principle of molecular reorientation induced by photoreaction of side chains and self-assembly based on liquid crystallinity. In the production method of the present invention, when the side chain type polymer has a structure in which a photocrosslinkable group is a photoreactive group, a liquid crystal display element is produced by forming a coating film on a substrate using the side chain type polymer, irradiating the coating film with polarized ultraviolet rays, and then heating the coating film.

Hereinafter, an embodiment of a side chain type polymer using a structure having a photocrosslinkable group as a photoreactive group will be referred to as an embodiment 1, and an embodiment of a side chain type polymer using a structure having a photofries rearrangement group or a group which undergoes isomerization as a photoreactive group will be referred to as an embodiment 2, and will be described.

Fig. 1 is a diagram schematically illustrating an example of an anisotropy introduction process in a method for producing a liquid crystal alignment film, in which a side chain polymer having a structure in which a photocrosslinkable group is a photoreactive group is used in embodiment 1 of the present invention. Fig. 1 (a) is a diagram schematically illustrating a state of the side chain type polymer film before the polarized light irradiation, fig. 1 (b) is a diagram schematically illustrating a state of the side chain type polymer film after the polarized light irradiation, fig. 1 (c) is a diagram schematically illustrating a state of the side chain type polymer film after the heating, and particularly, a diagram schematically illustrating a case where the introduced anisotropy is small, that is, in the 1 st aspect of the present invention, the ultraviolet irradiation amount in the [ II ] step is in a range of 1% to 15% of the maximum ultraviolet irradiation amount.

Fig. 2 is a view schematically illustrating an example of an anisotropy introduction process in a method for producing a liquid crystal alignment film, in which a side chain polymer having a structure in which a photocrosslinkable group is a photoreactive group is used in embodiment 1 of the present invention. Fig. 2 (a) is a diagram schematically illustrating a state of the side chain type polymer film before the polarized light irradiation, fig. 2 (b) is a diagram schematically illustrating a state of the side chain type polymer film after the polarized light irradiation, fig. 2 (c) is a diagram schematically illustrating a state of the side chain type polymer film after the heating, and particularly, a diagram when the introduced anisotropy is large, that is, in the 1 st aspect of the present invention, the ultraviolet irradiation amount in the [ II ] step is within a range of 15% to 70% of the ultraviolet irradiation amount at which Δ a is maximized.

Fig. 3 is a view schematically illustrating an example of the anisotropy introduction process in the method for producing a liquid crystal alignment film, in which a side chain polymer having a structure in which a photoisomerization group or a photo-fries rearrangement group represented by the above formula (18) is used as a photoreactive group in embodiment 2 of the present invention. Fig. 3 (a) is a diagram schematically illustrating a state of the side chain type polymer film before the polarized light irradiation, fig. 3 (b) is a diagram schematically illustrating a state of the side chain type polymer film after the polarized light irradiation, fig. 3 (c) is a diagram schematically illustrating a state of the side chain type polymer film after the heating, and particularly, a diagram when the introduced anisotropy is small, that is, in the 2 nd aspect of the present invention, the ultraviolet irradiation amount in the [ II ] step is in a range of 1% to 70% of the ultraviolet irradiation amount at which Δ a is maximized.

Fig. 4 is a view schematically illustrating an example of the anisotropy introduction process in the method for producing a liquid crystal alignment film, in which a side chain polymer having a structure in which a photo-fries rearrangement group represented by the above formula (19) is used as a photoreactive group in embodiment 2 of the present invention. Fig. 4 (a) is a diagram schematically illustrating a state of the side chain type polymer film before the polarized light irradiation, fig. 4 (b) is a diagram schematically illustrating a state of the side chain type polymer film after the polarized light irradiation, fig. 4 (c) is a diagram schematically illustrating a state of the side chain type polymer film after the heating, and particularly, a diagram when the introduced anisotropy is large, that is, in the 2 nd aspect of the present invention, the ultraviolet irradiation amount in the [ II ] step is in a range of 1% to 70% of the ultraviolet irradiation amount at which Δ a is maximized.

In the 1 st aspect of the present invention, when the ultraviolet irradiation amount in the [ II ] step is in the range of 1% to 15% of the ultraviolet irradiation amount at which Δ a is maximized by introducing the anisotropic treatment to the coating film, first, the coating film 1 is formed on the substrate. As shown in fig. 1 (a), the coating film 1 formed on the substrate has a structure in which the side chains 2 are randomly arranged. The mesogen component and the photosensitive group of the side chain 2 are also randomly oriented according to the random arrangement of the side chain 2 of the coating film 1, and the coating film 1 is isotropic.

In the 1 st aspect of the present invention, when the ultraviolet irradiation amount in the [ II ] step is in the range of 15% to 70% of the ultraviolet irradiation amount at which Δ a is maximized by introducing the anisotropic treatment to the coating film, first, the coating film 3 is formed on the substrate. As shown in fig. 2 (a), the coating film 3 formed on the substrate has a structure in which the side chains 4 are randomly arranged. The mesogen component and the photosensitive group of the side chain 4 are also randomly oriented by the random arrangement of the side chain 4 of the coating film 3, and the coating film 2 is isotropic.

In the 2 nd aspect of the present invention, when a liquid crystal alignment film using a side chain polymer having a structure with a photoisomerization group or a photo-fries rearrangement group represented by the above formula (18) is applied by introducing anisotropy into a coating film, when the amount of ultraviolet irradiation in the [ II ] step is in the range of 1% to 70% of the amount of ultraviolet irradiation with Δ a maximized, first, a coating film 5 is formed on a substrate. As shown in fig. 3 (a), the coating film 5 formed on the substrate has a structure in which the side chains 6 are arranged randomly. The mesogen component and the photosensitive group of the side chain 6 are also randomly oriented by the random arrangement of the side chain 6 of the coating film 5, and the side chain type polymer film 5 is isotropic.

In the 2 nd aspect of the present invention, when a liquid crystal alignment film using a side chain polymer having a structure of a photo-fries rearrangement group represented by the above formula (19) is applied by introducing anisotropy into a coating film, when the amount of ultraviolet irradiation in the [ II ] step is in the range of 1% to 70% of the amount of ultraviolet irradiation with Δ a maximized, first, a coating film 7 is formed on a substrate. As shown in fig. 4 (a), the coating film 7 formed on the substrate has a structure in which the side chains 8 are arranged randomly. The mesogen component and the photosensitive group of the side chain 8 are also randomly oriented by the random arrangement of the side chain 8 of the coating film 7, and the coating film 7 is isotropic.

In the 1 st aspect of the present embodiment, when the ultraviolet irradiation amount in the [ II ] step is in the range of 1% to 15% of the maximum ultraviolet irradiation amount Δ a, the isotropic coating film 1 is irradiated with polarized ultraviolet rays. As a result, as shown in fig. 1 (b), the photosensitive group of the side chain 2a having a photosensitive group among the side chains 2 arranged in the direction parallel to the polarization direction of ultraviolet rays preferentially undergoes a photoreaction such as dimerization. As a result, the density of the photoreactive side chain 2a is slightly increased in the polarization direction of the ultraviolet light, and as a result, very small anisotropy is imparted to the coating film 1.

In the 1 st aspect of the present embodiment, when the ultraviolet irradiation amount in the [ II ] step is in the range of 15% to 70% of the maximum ultraviolet irradiation amount Δ a, the isotropic coating film 3 is irradiated with polarized ultraviolet rays. As a result, as shown in fig. 2 (b), the photosensitive group of the side chain 4a having a photosensitive group among the side chains 4 arranged in the direction parallel to the polarization direction of ultraviolet rays preferentially undergoes a photoreaction such as dimerization. As a result, the density of the photoreactive side chain 4a increases in the polarization direction of the irradiated ultraviolet light, and as a result, small anisotropy is imparted to the coating film 3.

In embodiment 2 of the present invention, a liquid crystal alignment film using a side chain polymer having a structure with a photoisomerization group or a photo-fries rearrangement group represented by formula (18) is used, and when the amount of ultraviolet irradiation in the step [ II ] is within a range of 1% to 70% of the amount of ultraviolet irradiation at which Δ a is maximized, polarized ultraviolet rays are irradiated to the isotropic coating film 5. As a result, as shown in fig. 3 (b), the photoreaction such as photo-fries rearrangement occurs preferentially in the photosensitive group of the side chain 6a having a photosensitive group among the side chains 6 arranged in the direction parallel to the polarization direction of the ultraviolet light. As a result, the density of the photoreactive side chain 6a is slightly increased in the polarization direction of the ultraviolet light, and as a result, very small anisotropy is imparted to the coating film 5.

In embodiment 2 of the present embodiment, a coating film using a side chain polymer having a structure with a photo-fries rearrangement group represented by the above formula (19) is applied, and when the amount of ultraviolet irradiation in the [ II ] step is in the range of 1% to 70% of the amount of ultraviolet irradiation with Δ a at maximum, polarized ultraviolet rays are irradiated to the isotropic coating film 7. As a result, as shown in fig. 4 (b), the photoreaction such as photo-fries rearrangement occurs preferentially in the photosensitive group of the side chain 8a having a photosensitive group among the side chains 8 arranged in the direction parallel to the polarization direction of the ultraviolet light. As a result, the density of the photoreactive side chain 8a increases in the polarization direction of the irradiated ultraviolet light, and as a result, small anisotropy is imparted to the coating film 7.

Next, in embodiment 1 of the present embodiment, when the ultraviolet irradiation amount in the [ II ] step is in the range of 1% to 15% of the maximum ultraviolet irradiation amount Δ a, the coating film 1 irradiated with polarized light is heated to be in a liquid crystal state. As a result, as shown in fig. 1 (c), the amount of crosslinking reaction that occurs in the coating film 1 differs between the direction parallel to the polarization direction of the irradiated ultraviolet light and the direction perpendicular to the polarization direction of the irradiated ultraviolet light. In this case, since the amount of the crosslinking reaction occurring in the direction parallel to the polarization direction of the irradiated ultraviolet ray is very small, the crosslinking reaction site functions as a plasticizer. Therefore, the liquid crystallinity in the direction perpendicular to the polarization direction of the irradiated ultraviolet ray is higher than the liquid crystallinity in the direction parallel to the polarization direction of the irradiated ultraviolet ray, and the self-assembly occurs in the direction parallel to the polarization direction of the irradiated ultraviolet ray, and the side chain 2 including the mesogen component is reoriented. As a result, the very small anisotropy of the coating film 1 induced by the photocrosslinking reaction is amplified by heat, and a larger anisotropy is imparted to the coating film 1.

Similarly, in the embodiment 1 of the present embodiment, when the ultraviolet irradiation amount in the [ II ] step is in the range of 15% to 70% of the ultraviolet irradiation amount at which Δ a is maximized, the coating film 3 after the polarized light irradiation is heated to be in a liquid crystal state. As a result, as shown in fig. 2 (c), the side chain polymer film 3 has a difference in the amount of crosslinking reaction occurring between the direction parallel to the polarization direction of the irradiated ultraviolet ray and the direction perpendicular to the polarization direction of the irradiated ultraviolet ray. Therefore, the self-assembly occurs in the direction parallel to the polarization direction of the irradiated ultraviolet ray, and the side chain 4 including the mesogen component is reoriented. As a result, the small anisotropy of the coating film 3 induced by the photocrosslinking reaction is amplified by heat, and a larger anisotropy is imparted to the coating film 3.

Similarly, in embodiment 2 of the present embodiment, a coating film using a side chain polymer having a structure with a photoisomerizable group or a photo-fries rearrangement group represented by the above formula (18) is applied, and when the ultraviolet irradiation amount in the [ II ] step is in the range of 1% to 70% of the maximum ultraviolet irradiation amount, the coating film 5 after the polarized light irradiation is heated to be in a liquid crystal state. As a result, as shown in fig. 3 (c), the amount of the photo fries rearrangement reaction that occurs in the coating film 5 differs between the direction parallel to the polarization direction of the irradiated ultraviolet light and the direction perpendicular to the polarization direction of the irradiated ultraviolet light. At this time, since the liquid crystal alignment force of the photo-fries rearrangement occurring in the direction perpendicular to the polarization direction of the irradiated ultraviolet ray is stronger than the liquid crystal alignment force of the side chain before the reaction, the direction perpendicular to the polarization direction of the irradiated ultraviolet ray is self-assembled, and the side chain 6 including the liquid crystal original component is re-aligned. As a result, the very small anisotropy of the coating film 5 induced by the photo-fries rearrangement reaction is amplified by heat, and a larger anisotropy is imparted to the coating film 5.

Similarly, in embodiment 2 of the present embodiment, a coating film using a side chain polymer having a structure with a photo-fries rearrangement group represented by formula (19) is applied, and when the amount of ultraviolet irradiation in the [ II ] step is in the range of 1% to 70% of the amount of ultraviolet irradiation with Δ a at the maximum, the coating film 7 after polarized light irradiation is heated to be in a liquid crystal state. As a result, as shown in fig. 4 (c), the amount of photo fries rearrangement reaction that occurs in the side chain polymer film 7 differs between the direction parallel to the polarization direction of the irradiated ultraviolet light and the direction perpendicular to the polarization direction of the irradiated ultraviolet light. Since the anchoring strength of the photo-fries rearrangement 8(a) is stronger than that of the side chain 8 before the rearrangement, when a certain amount or more of the photo-fries rearrangement occurs, self-assembly occurs in a direction parallel to the polarization direction of the irradiated ultraviolet rays, and the side chain 8 including the mesogen component is reoriented. As a result, the small anisotropy of the coating film 7 induced by the photo-fries rearrangement reaction is amplified by heat, and a larger anisotropy is imparted to the coating film 7.

Therefore, the coating film used in the method of the present invention can be made into a liquid crystal alignment film having excellent alignment controllability by efficiently introducing anisotropy into the coating film by sequentially performing irradiation of polarized ultraviolet rays and heat treatment on the coating film.

The coating film used in the method of the present invention is optimized in the irradiation amount of polarized ultraviolet rays to be irradiated to the coating film and the heating temperature for the heating treatment. This enables efficient introduction of anisotropy into the coating film.

The irradiation amount of polarized ultraviolet ray optimal for efficiently introducing anisotropy into the coating film used in the present invention corresponds to the irradiation amount of polarized ultraviolet ray that optimizes the amount of photocrosslinking reaction, photoisomerization reaction, or photofries rearrangement reaction of the photosensitive group in the coating film. When the photosensitive group of the side chain which undergoes a photocrosslinking reaction, a photoisomerization reaction or a photoFries rearrangement reaction is small as a result of irradiating polarized ultraviolet rays to the coating film used in the present invention, a sufficient photoreactive amount cannot be obtained. In this case, sufficient self-assembly does not proceed even after the subsequent heating. On the other hand, in the coating film used in the present invention, when the photosensitive group of the side chain which undergoes the crosslinking reaction is excessive as a result of irradiating the structure having the photocrosslinkable group with polarized ultraviolet rays, the crosslinking reaction between the side chains proceeds excessively. At this time, the obtained film becomes rigid, and the progress of self-assembly by heating thereafter may be hindered. In addition, when the structure having a photo-fries rearrangement group is irradiated with polarized ultraviolet light, and the photosensitive group of the side chain having a photo-fries rearrangement reaction is excessively increased, the liquid crystallinity of the coating film is excessively decreased. In this case, the liquid crystallinity of the obtained film is also reduced, and the progress of self-assembly by heating may be hindered. Further, when polarized ultraviolet light is irradiated to a structure having a photo-fries rearrangement group, if the irradiation amount of ultraviolet light is too large, the side chain polymer is photolyzed, and the progress of self-assembly by heating thereafter may be hindered.

Therefore, in the coating film used in the present invention, the optimum amount of the side-chain photosensitive group to undergo the photocrosslinking reaction, photoisomerization reaction, or photo fries rearrangement reaction by irradiation with polarized ultraviolet light is preferably 0.1 to 40 mol%, more preferably 0.1 to 20 mol%, of the photosensitive group of the side-chain polymer film. When the amount of the photosensitive group in the side chain to be photoreactive is in such a range, self-assembly in the subsequent heat treatment advances efficiently, and high-efficiency anisotropy in the film can be formed.

In the coating film used in the method of the present invention, the amount of photocrosslinking reaction, photoisomerization reaction, or photofries rearrangement reaction of the photosensitive group in the side chain of the side chain-type polymer film is optimized by optimizing the irradiation amount of the polarized ultraviolet ray. Further, the anisotropy can be efficiently introduced into the coating film used in the present invention together with the subsequent heat treatment. In this case, the appropriate amount of polarized ultraviolet light can be evaluated based on the ultraviolet absorption of the coating film used in the present invention.

That is, with respect to the coating film used in the present invention, ultraviolet absorption in a direction parallel to the polarization direction of the polarized ultraviolet ray and ultraviolet absorption in a direction perpendicular to the polarization direction of the polarized ultraviolet ray after irradiation with the polarized ultraviolet ray were measured. From the measurement result of the ultraviolet absorption, Δ a, which is the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet ray and the ultraviolet absorbance in the direction perpendicular to the polarization direction of the polarized ultraviolet ray in the coating film, was evaluated. Then, the maximum value of Δ a (Δ Amax) realized in the coating film used in the present invention and the irradiation amount of polarized ultraviolet rays realizing this were obtained. In the production method of the present invention, the amount of polarized ultraviolet light irradiated with a preferred amount in the production of the liquid crystal alignment film can be determined with reference to the amount of polarized ultraviolet light irradiation that achieves Δ Amax.

In the production method of the present invention, the irradiation amount of the polarized ultraviolet ray with which the coating film used in the present invention is irradiated is preferably in the range of 1% to 70%, more preferably in the range of 1% to 50%, of the amount of the polarized ultraviolet ray that realizes Δ Amax. In the coating film used in the present invention, the irradiation amount of polarized ultraviolet light in the range of 1% to 50% of the amount of polarized ultraviolet light that can achieve Δ Amax corresponds to the amount of polarized ultraviolet light that causes a photocrosslinking reaction of 0.1% to 20% by mole of the entire photosensitive groups of the side chain polymer film.

As described above, in the production method of the present invention, in order to efficiently introduce anisotropy into a coating film, the above-described appropriate heating temperature may be determined based on the liquid crystal temperature range of the side chain polymer. Therefore, for example, when the liquid crystal temperature of the side chain polymer used in the present invention is 150 to 250 ℃, the temperature for heating after irradiation with polarized ultraviolet rays is desirably 140 to 240 ℃. By setting in this way, a coating film used in the present invention is provided 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 a 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 is excellent in reliability and can be suitably used for a large-screen and high-definition liquid crystal television or the like.

Examples

Abbreviations used in the examples are as follows.

(methacrylic monomer)

MA1 was synthesized by a synthesis method described in patent document (WO 2011/084546).

< organic solvent >

THF: tetrahydrofuran (THF)

NMP: n-methyl-2-pyrrolidone

NEP: n-ethyl-2-pyrrolidone

BCS: butyl cellosolve

PB: propylene glycol monobutyl ether

< polymerization initiator >

AIBN: 2, 2' -azobisisobutyronitrile

< Synthesis of Polymer >

MA1(9.97g, 30.0mmol) was dissolved in THF (92.0g), degassed with a diaphragm pump, and AIBN (0.246g, 1.5mmol) was added and degassed again. Thereafter, the reaction was carried out at 50 ℃ for 30 hours to obtain a polymer solution of methacrylate ester. The polymer solution was added dropwise to diethyl ether (1000ml), and the resulting precipitate was filtered. The precipitate was washed with diethyl ether and dried under reduced pressure in an oven at 40 ℃ to obtain a methacrylate polymer powder (a). The polymer had a number average molecular weight of 16000 and a weight average molecular weight of 32000.

The liquid crystal phase transition temperature of the obtained methacrylate polymer is 145-190 ℃.

< example 1>

NEP (49.0g) was added to the obtained methacrylate polymer powder (A) (6.0g), and the mixture was stirred at room temperature for 5 hours to dissolve it. BCS (45.0g) was added to the solution and stirred to obtain a liquid crystal aligning agent (A1).

< example 2>

To the obtained methacrylate polymer powder (A) (6.0g) was added NMP (49.0g), and the mixture was stirred at room temperature for 5 hours to dissolve it. To this solution, PB (45.0g) was added and stirred to obtain a liquid crystal alignment agent (a 2).

< example 3>

NEP (49.0g) was added to the obtained methacrylate polymer powder (A) (6.0g), and the mixture was stirred at room temperature for 5 hours to dissolve it. To this solution, PB (45.0g) was added and stirred to obtain a liquid crystal alignment agent (a 3).

< control 1>

To the obtained methacrylate polymer powder (A) (6.0g) was added NMP (49.0g), and the mixture was stirred at room temperature for 5 hours to dissolve it. BCS (45.0g) was added to the solution and stirred to obtain a liquid crystal aligning agent (control 1).

The liquid crystal aligning agent obtained in the examples of the present invention was used to evaluate the ink jet coatability of the liquid crystal aligning agent. The conditions are as follows.

The liquid crystal aligning agent (a1) obtained in example 1 of the present invention, the liquid crystal aligning agent (a2) obtained in example 2, the liquid crystal aligning agent (A3) obtained in example 3, and the liquid crystal aligning agent (control 1) obtained in control 1 were subjected to pressure filtration using a membrane filter having a pore diameter of 1 μm to evaluate the ink jet coatability.

As the ink jet coater, HIS-200 (manufactured by Hitachi Plant Technologies, Ltd.) was used. The coating was carried out as follows: on an ITO (indium tin oxide) vapor-deposited substrate cleaned with pure water and IPA (isopropyl alcohol), the coating area was 80X 72mm, the nozzle pitch was 0.423mm, the scanning pitch was 0.5mm, the coating speed was 40 mm/sec, the time from coating to predrying was 30 seconds, and the predrying was performed on a hot plate at 70 ℃ for 90 seconds.

With respect to the obtained liquid crystal alignment film, the "end linearity" and "end protrusion" of the liquid crystal alignment film were evaluated.

The linearity of the end of the liquid crystal alignment film was evaluated by observing the liquid crystal alignment film at the right end in the printing direction with an optical microscope (ECLIPSE ME600, manufactured by nikon corporation). Specifically, the difference between (1) and (2) in fig. 5, i.e., the length a in fig. 5, of the liquid crystal alignment film image obtained by observation at a magnification of 25 times was measured by an optical microscope. At this time, images of all the liquid crystal alignment films are obtained at the same magnification. In the evaluation, the shorter the length of a, the more excellent the linearity of the end portion of the liquid crystal alignment film.

The end protrusion of the liquid crystal alignment film was evaluated by observing the liquid crystal alignment film at the right end in the printing direction with an optical microscope. Specifically, the length of B in fig. 6 of the liquid crystal alignment film image observed at a magnification of 25 times was measured by an optical microscope. At this time, images of all the liquid crystal alignment films are obtained at the same magnification. In the evaluation, the shorter the length of B, the more excellent the end portion protrusion of the liquid crystal alignment film.

The results are shown in the following table. The length of A and the length of B of the liquid crystal alignment film obtained in the examples are shown in the table.

[ Table 2]

According to the results, the liquid crystal alignment film of the liquid crystal alignment agent according to the example (the present invention) had high linearity at the end portions and small protrusion at the end portions.

Description of the reference numerals

FIG. 1 shows a schematic view of a

1-side chain type polymeric membrane

2. 2a side chain

FIG. 2

3-side chain type polymeric membrane

4. 4a side chain

FIG. 3

5-side chain type polymer film

6. 6a side chain

FIG. 4

7 side chain type polymeric membrane

8. 8a side chain

FIG. 5

9 liquid crystal alignment film

10 ITO (indium tin oxide) evaporation substrate

FIG. 6

11 liquid crystal alignment film

12 ITO (indium tin oxide) evaporation substrate

Claims

1. A polymer composition comprising:

(A) photosensitive side chain type polymer exhibiting liquid crystallinity in a specific temperature range, and

(B) an organic solvent, and a solvent mixture comprising an organic solvent,

the organic solvent contains both a good solvent and a poor solvent for the side chain polymer, and the good solvent having a boiling point of 180 ℃ or higher is contained in an amount of 10 mass% or more per 100 parts by mass of the good solvent on average,

the poor solvent comprises propylene glycol monobutyl ether,

the content of the propylene glycol monobutyl ether is 5-70 mass percent of the organic solvent,

the good solvent includes 1 or more specific good solvents selected from the group consisting of N, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), 1, 3-Dimethylimidazolidinone (DMI), and Propylene Glycol Monomethyl Ether (PGME).

2. The composition of claim 1 wherein component (a) has photosensitive side chains that undergo photocrosslinking, photoisomerization or photofries rearrangement.

3. The composition according to claim 1 or 2, wherein the good solvent in the component (B) further comprises N-ethyl-2-pyrrolidone (NEP).

4. The composition according to claim 1 or 2, wherein component (A) has any one of photosensitive side chains selected from the group consisting of the following formulas (1) to (6),

Y₁represents a ring selected from a 1-valent 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 a group in which 2 to 6 identical or different rings selected from these substituents are bonded via a bonding group B, and hydrogen atoms bonded to these are each independently optionally substituted by-COOR₀、-NO₂、-CN、-CH＝C(CN)₂a-CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, wherein R is₀Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;

one of q1 and q2 is 1 and the other is 0;

q3 is 0 or 1;

l1 is 0 or 1;

l2 is an integer of 0 to 2;

when l1 and l2 are both 0, A represents a single bond when T is a single bond;

when l1 is 1, B represents a single bond when T is a single bond;

5. The composition according to claim 1 or 2, wherein the component (A) has any one of photosensitive side chains selected from the group consisting of the following formulas (7) to (10),

Y₁represents a carbon number selected from 1-valent benzene ring, naphthalene ring, biphenyl ring, furan ring, pyrrole ring and5 to 8 rings in the alicyclic hydrocarbon, or 2 to 6 rings selected from these substituents, which may be the same or different, bonded via a bonding group B, and hydrogen atoms bonded thereto are each independently optionally substituted by-COOR₀、-NO₂、-CN、-CH＝C(CN)₂a-CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, wherein R is₀Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, m1 and m2 represent an integer of 1 to 3;

n represents an integer of 0 to 12, wherein when n is 0, B is a single bond;

r represents a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to Y₁The same definition.

6. The composition according to claim 1 or 2, wherein component (A) has any one of photosensitive side chains selected from the group consisting of the following formulas (11) to (13),

wherein A each independently represents a single bond, -O-, -CH₂-, -COO-, -OCO-, -CONH-, -NH-CO-, -CH-CO-O-or-O-CO-CH-;

l represents an integer of 1 to 12, m represents an integer of 0 to 2, and m1 represents an integer of 1 to 3;

r represents a ring selected from among 1-valent benzene rings, naphthalene rings, biphenyl rings, furan rings, pyrrole rings and C5-8 alicyclic hydrocarbons, or a group in which 2 to 6 identical or different rings selected from among these substituents are bonded via a bonding group B, and hydrogen atoms bonded thereto are each independently optionally substituted by-COOR₀、-NO₂、-CN、-CH＝C(CN)₂a-CH-CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, or R represents a hydroxyl group or an alkoxy group having 1 to 6 carbon atoms, wherein R represents₀Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

7. The composition according to claim 1 or 2, wherein the component (A) has a photosensitive side chain represented by the following formula (14) or (15),

l represents an integer of 1 to 12, and m1 and m2 represent an integer of 1 to 3.

8. The composition according to claim 1 or 2, wherein the component (A) has a photosensitive side chain represented by the following formula (16) or (17),

wherein A represents a single bond, -O-, -CH₂-, -COO-, -OCO-, -CONH-, -NH-CO-, -CH-CO-O-or-O-CO-CH-;

l represents an integer of 1 to 12, and m represents an integer of 0 to 2.

9. The composition according to claim 1 or 2, wherein the component (A) has any one photosensitive side chain selected from the group consisting of the following formulas (18) or (19),

wherein A, B each independently represents a single bond, -O-, -CH₂-, -COO-, -OCO-, -CONH-, -NH-CO-, -CH-CO-O-or-O-CO-CH-;

one of q1 and q2 is 1 and the other is 0;

l represents an integer of 1 to 12, m1 and m2 represent an integer of 1 to 3;

10. The composition according to claim 1 or 2, wherein the component (A) has a photosensitive side chain represented by the following formula (20),

l represents an integer of 1 to 12, and m represents an integer of 0 to 2.

11. The composition according to claim 1 or 2, wherein component (A) has any one liquid crystalline side chain selected from the group consisting of the following formulas (21) to (31),

wherein A and B have the same meanings as defined above;

one of q1 and q2 is 1 and the other is 0;

Z₁、Z₂represents a single bond, -CO-, -CH₂O-、-CH＝N-、-CF₂-。

12. A method for manufacturing a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element, the method comprising the steps of:

[I] a step of forming a coating film by applying the composition according to any one of claims 1 to 11 onto a substrate having a conductive film for driving a transverse electric field;

and [ III ] a step of heating the coating film obtained in [ II ].

13. A substrate having a liquid crystal alignment film for a transverse electric field-driven liquid crystal display element, which is produced by the method according to claim 12.

14. A transverse electric field driving type liquid crystal display element having the substrate according to claim 13.

15. A method for manufacturing a transverse electric field driven liquid crystal display element, comprising the steps of:

preparing a1 st substrate as the substrate according to claim 13;

[ IV ] a step of disposing the 1 st substrate and the 2 nd substrate in opposition to each other with the liquid crystal alignment films of the 1 st substrate and the 2 nd substrate facing each other with the liquid crystal interposed therebetween to obtain a liquid crystal display element,

the processes [ I ' ], [ II ' ] and [ III ' ] are:

[ I' ] a step of forming a coating film by applying a polymer composition on a2 nd substrate, the polymer composition comprising: (A) a photosensitive side chain polymer exhibiting liquid crystallinity in a specific temperature range, and (B) an organic solvent which contains both a good solvent and a poor solvent for the side chain polymer, wherein the good solvent contains 10 mass% or more of the good solvents having a boiling point of 180 ℃ or higher among the good solvents on average 100 parts by mass, the good solvent contains 1 or more specific good solvents selected from solvents having a boiling point of 100 to 230 ℃ and a surface tension of less than 41.0dyn/cm, and/or the poor solvent contains propylene glycol monobutyl ether;

[ III '] heating the coating film obtained in [ II' ].

16. A transverse electric field driven type liquid crystal display element produced by the method according to claim 15.