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

Abstract

The present invention provides a simple method for manufacturing a VA mode liquid crystal display element that forms multiple regions with different orientation directions (orientation division) and has excellent viewing angle characteristics. The present invention is a method for manufacturing a multi-domain liquid crystal alignment film, which sequentially includes the following steps: a step of coating a liquid crystal alignment agent on a substrate to form a cured film, wherein the liquid crystal alignment agent contains a solvent and a polymer having a photo-alignment group and a thermal crosslinking group A as a component (A), and satisfies at least one of the following Z1 and Z2; a first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction; and a second irradiation step of irradiating the cured film with ultraviolet rays from a direction different from the first irradiation step, at least one of the irradiation steps is performed through a mask including a light-shielding area and a non-light-shielding area. Z1: The (A) component also has a thermal crosslinking group B. Z2: As the (B) component, a compound having a thermal crosslinking group B is also contained.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a liquid crystal alignment film using a liquid crystal alignment agent, a liquid crystal alignment film obtained therefrom, and a liquid crystal display element having the obtained liquid crystal alignment film. More specifically, the present invention relates to a liquid crystal alignment film having a low firing temperature, good liquid crystal orientation even when the firing time is short, excellent pretilt angle performance, high reliability, and the ability to overwrite the pretilt angle, and a method for manufacturing a multi-domain liquid crystal alignment film having excellent display quality using a specific liquid crystal alignment agent, a multi-domain liquid crystal alignment film, and a liquid crystal display element. Background Art

[0002] In a liquid crystal display element, a liquid crystal alignment film plays the role of orienting liquid crystals in a certain direction. Currently, the main liquid crystal alignment film used in industry is produced by applying a polyimide-based liquid crystal alignment agent formed from a solution of polyamic acid (also called polyamic acid), polyamic acid ester, or polyimide, which is a polyimide precursor, to a substrate to form a film.

[0003] Furthermore, when the liquid crystal is aligned parallel or obliquely with respect to the substrate surface, after the film is formed, a surface stretching treatment is further performed by rubbing.

[0004] On the other hand, when the liquid crystal is oriented vertically relative to the substrate (called vertical alignment (VA) mode), a liquid crystal alignment film is used in which a hydrophobic group such as a long-chain alkyl group, a cyclic group or a combination of a cyclic group and an alkyl group (for example, see Patent Document 1), a steroid skeleton (for example, see Patent Document 2) is introduced into the side chain of a polyimide. At this time, when a voltage is applied between the substrates to tilt the liquid crystal molecules in a direction parallel to the substrate, it is necessary to tilt the liquid crystal molecules from the normal direction of the substrate toward one direction in the substrate surface. As means for this, the following methods are proposed, for example: a method of providing a protrusion on the substrate; a method of providing a slit in the display electrode; a method of pre-tilting the liquid crystal molecules from the normal direction of the substrate toward one direction in the substrate surface by brushing; and a method of pre-adding a photopolymerizable compound to the liquid crystal composition, using it together with a vertical alignment film of polyimide, etc., applying a voltage to the liquid crystal unit while irradiating ultraviolet rays, thereby pre-tilting the liquid crystal (for example, see Patent Document 3), etc.

[0005] In recent years, as a method to replace the formation of protrusions or slits in the liquid crystal orientation control of the VA method and the PSA technology, a method (photo-orientation method) using anisotropic photochemical reactions based on polarized ultraviolet irradiation, etc. has also been proposed. That is, it is known that by irradiating polarized ultraviolet rays to a polyimide film with photoreactive vertical orientation, the orientation control ability and pre-tilt angle performance are given, so that the tilt direction of the liquid crystal molecules when the voltage is applied can be uniformly controlled (see patent document 4). At this time, a polyimide-based liquid crystal orientation film with excellent durability and suitable for controlling the pre-tilt angle of the liquid crystal is used in the same way as the previous orientation film. The polyimide-based liquid crystal orientation film is usually fired at a high temperature of more than 200°C.

[0006] On the other hand, research is also devoted to the use of thin plastic substrates as substrates of liquid crystal display elements. At this time, due to the low heat resistance of plastic substrates, it is necessary to perform firing at a lower temperature when making liquid crystal alignment films. Similarly, it is also sought to reduce the energy cost in the manufacture of liquid crystal display elements by setting the firing temperature to a low temperature.

[0007] When firing is performed at a low temperature, there is a problem that curing must be completed when the alignment film material is not fully cured, and it is difficult to obtain a liquid crystal display element with high reliability (see, for example, Patent Document 5).

[0008] On the other hand, the demand for multi-domain technology to form multiple regions with different orientation directions (orientation segmentation) is increasing, but in the previous manufacturing method, it is necessary to use an exposure mask with multiple openings at specified intervals for exposure, and then stagger the exposure mask by only a specified interval and expose again. High precision is required for the alignment of the exposure mask and the formation of multiple openings. The manufacturing process is complicated and improvements are sought. Here, it is known to use a method for manufacturing a multi-domain liquid crystal display element using a polymer with a vertical alignment group bonded to a photodegradable polyimide, but a very large amount of light irradiation is required, and the manufacturing efficiency is poor (for example, refer to patent documents 6, 7 and 8). There are also examples of methods for manufacturing multi-domain alignment films, but it is not clear which alignment film can be used to implement the invention (for example, refer to patent document 9).

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 3-179323

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 4-281427

[0013] Patent Document 3: Japanese Patent No. 4504626

[0014] Patent Document 4: Japanese Patent No. 4995267

[0015] Patent Document 5: Japanese Patent Application Laid-Open No. 7-209633

[0016] Patent Document 6: Japanese Patent Application Laid-Open No. 11-95224

[0017] Patent Document 7: Japanese Patent Application Publication No. 2005-148442

[0018] Patent Document 8: Japanese Patent Application Publication No. 2005-316027

[0019] Patent Document 9: Japanese Patent Application Publication No. 2007-219191 Summary of the invention

[0020] Problem that the invention aims to solve

[0021] An object of the present invention is to provide a VA mode liquid crystal display element which can form a plurality of regions having different alignment directions (alignment division) more simply with fewer mask processing steps and has excellent viewing angle characteristics, and a method for producing the same.

[0022] Furthermore, an object of the present invention is to provide an ECB liquid crystal display element having improved viewing angle characteristics and a liquid crystal alignment film used for the element in addition to the above-mentioned object.

[0023] Solutions for solving problems

[0024] The present inventors have found that <x>Invention as a subject.

[0025] <x>A method for manufacturing a multi-domain liquid crystal alignment film, characterized in that it comprises the following steps in sequence:

[0026] A process of coating a liquid crystal alignment agent on a substrate, and forming a cured film by drying and firing, wherein the liquid crystal alignment agent contains a solvent and a polymer having a photo-alignment group represented by the following formula (pa-1) and a thermally crosslinkable group A as component (A), and satisfies at least one of the following necessary conditions Z1 and Z2;

[0027] a first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction; and

[0028] A second irradiation step of irradiating the cured film with ultraviolet rays from a direction different from that of the first irradiation step,

[0029] At least one of the first irradiation step and the second irradiation step is performed through a mask including a light-shielding region and a non-light-shielding region.

[0030] Z1: The polymer as the component (A) further has a thermally crosslinkable group B.

[0031] Z2: A compound having two or more thermally crosslinkable groups B in the molecule is further contained as the component (B).

[0032]

[0033] In the formula, A represents pyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene, 1,4-naphthylene or phenylene, or 2,6-naphthylene or phenylene, which is substituted by a group selected from fluorine, chlorine, and cyano, or substituted by an alkoxy group having 1 to 5 carbon atoms, a linear or branched alkyl residue (which is substituted by one cyano group or one or more halogen atoms, as appropriate); R1 is a single bond, an oxygen atom, -COO- or -OCO-; R2 is a divalent aromatic group, a divalent alicyclic group, a divalent heterocyclic group, or a divalent condensed ring group; R3 is a single bond, an oxygen atom, -COO- or -OCO-; R4 is a linear or branched alkyl group having 1 to 40 carbon atoms, or a monovalent organic group having 3 to 40 carbon atoms including an alicyclic group; D represents an oxygen atom, a sulfur atom, or -NR d -(Here, R d represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms); a is an integer from 0 to 3; and * represents a bonding position.

[0034] The thermally crosslinkable group A and the thermally crosslinkable group B are each independently an organic group selected from the group consisting of a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, a group containing an epoxy portion, an oxetane group, a thiranyl group, an isocyanate group and a blocked isocyanate group, and are selected in such a way that the thermally crosslinkable group A and the thermally crosslinkable group B undergo a crosslinking reaction due to heat, wherein the thermally crosslinkable group A and the thermally crosslinkable group B are optionally the same as each other.

[0035] Effects of the Invention

[0036] According to the present invention, a VA mode liquid crystal display element can be provided which is capable of more easily forming a plurality of regions having different alignment directions (alignment division) with fewer mask processing steps and has excellent viewing angle characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 θ represents the irradiation angle in the first irradiation step, Φ represents the irradiation angle in the second irradiation step, and Ψ represents the inclination angle. DETAILED DESCRIPTION

[0038] The method for manufacturing a multi-domain liquid crystal alignment film of the present invention is characterized in that it comprises the following steps in sequence:

[0039] A process of coating a liquid crystal alignment agent on a substrate, and forming a cured film by drying and firing, wherein the liquid crystal alignment agent contains a solvent and a polymer having a photo-alignment group represented by the above formula (pa-1) and a thermally crosslinkable group A as component (A), and satisfies at least one of the following necessary conditions Z1 and Z2;

[0040] a first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction; and

[0041] A second irradiation step of irradiating the cured film with ultraviolet rays from a direction different from that of the first irradiation step,

[0042] At least one of the first irradiation step and the second irradiation step is performed through a mask including a light-shielding region and a non-light-shielding region.

[0043] Z1: The polymer as the component (A) further has a thermally crosslinkable group B.

[0044] Z2: A compound having two or more thermally crosslinkable groups B in the molecule is further contained as the component (B).

[0045] The thermally crosslinkable group A and the thermally crosslinkable group B are each independently an organic group selected from the group consisting of a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, a group containing an epoxy portion, an oxetane group, a thiirane group, an isocyanate group and a blocked isocyanate group, and are selected in such a way that the thermally crosslinkable group A and the thermally crosslinkable group B undergo a crosslinking reaction due to heat, wherein the thermally crosslinkable group A and the thermally crosslinkable group B are optionally the same as each other.

[0046] Here, "having two or more in the molecule" means as follows: in addition to the case where two or more groups of the same kind are contained in the molecule, such as two or more epoxy groups, the case where a total of two or more different groups are contained in the molecule, such as a combination of an epoxy group and a thiirane group, is also included. "Having two or more in the molecule" preferably means that two or more groups of the same kind are contained in the molecule.

[0047] Since the polymer as the (A) component contained in the liquid crystal aligning agent of the present invention has high sensitivity to light, the alignment control ability can be expressed even when irradiated with polarized ultraviolet rays at a low exposure amount.

[0048] In addition, by making the polymer as the component (A) contain a heat-crosslinkable group A, and further containing a heat-crosslinkable group B in the component, a crosslinking reaction of the polymer as the component (A) can occur even when the firing time of the liquid crystal alignment agent is short. Thus, when the photo-alignment site exhibits anisotropy due to the photoreaction, the anisotropy is easily retained (stored) in the liquid crystal alignment film, and therefore, the liquid crystal orientation can be improved and the pre-tilt angle of the liquid crystal can be exhibited.

[0049] It should be noted that the part having the photo-alignment group represented by the above formula (pa-1) (for example, the group represented by the formula (a-1) described later), the thermally crosslinkable group A and the thermally crosslinkable group B can all form side chains in the polymer and therefore may be referred to as "side chains" as needed.

[0050] Hereinafter, each constituent requirement of the present invention will be described in detail.

[0051] <Component (A): Specific polymer>

[0052] [Photo-aligning group represented by formula (pa-1)]

[0053] In the present invention, the photo-aligned site represented by the above formula (pa-1) in the molecule can be represented by, for example, the following formula (a-1). In addition, the site can be a structure derived from a monomer represented by the following formula (a-1-m), but is not limited thereto. a It is a monovalent organic group represented by the following formula (pa-1).

[0054] ——S a ——I a (a-1)

[0055]

[0056] In the formula (pa-1), A represents pyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene, 1,4-naphthylene or phenylene, or 2,6-naphthylene or phenylene, which is substituted by a group selected from fluorine, chlorine, and cyano, or by an alkoxy group having 1 to 5 carbon atoms, a linear or branched alkyl residue (which is substituted by one cyano group or one or more halogen atoms, depending on the situation); R1 is a single bond, an oxygen atom, -COO- or -OCO-; R2 is a divalent aromatic group, a divalent alicyclic group, a divalent heterocyclic group, or a divalent condensed ring group; R3 is a single bond, an oxygen atom, -COO- or -OCO-; R4 is a linear or branched alkyl group having 1 to 40 carbon atoms, or a monovalent organic group having 3 to 40 carbon atoms including an alicyclic group; D represents an oxygen atom, a sulfur atom, or -NR d -(Here, R d represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms); a is an integer from 0 to 3; * represents the same as S a bonding position.

[0057] In the above formula (a-1) or (a-1-m), S a represents the spacer unit, S a The linking group on the left side represents the main chain bonded to the first specific polymer and the second specific polymer, optionally via a spacer group.

[0058] S a For example, it can be represented by the structure of the following formula (Sp).

[0059]

[0060] In formula (Sp),

[0061] The key on the left side of W1 indicates the same b Bonded keys,

[0062] The key on the right side of W3 represents the same a Bonded keys,

[0063] W1, W2 and W3 each independently represent a single bond, a divalent heterocycle, -(CH2) n -(wherein n represents 1 to 20), -OCH2-, -CH2O-, -COO-, -OCO-, -CH=CH-, -CF=CF-, -CF2O-, -OCF2-, -CF2CF2- or -C≡C-, one or more non-adjacent CH2 groups in these substituents may be independently replaced by -O-, -CO-, -CO-O-, -O-CO-, -Si(CH3)2-O-Si(CH3)2-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-O-, -OCO-NR-, -NR-CO-NR-, -CH=CH-, -C≡C- or -O-CO-O-(wherein R independently represents hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms),

[0064] A1 and A2 are each independently a single bond, a group selected from a divalent alkyl group, a divalent aromatic group, a divalent alicyclic group or a divalent heterocyclic group, and each group is unsubstituted or one or more hydrogen atoms are optionally substituted by a fluorine atom, a chlorine atom, a cyano group, a methyl group or a methoxy group.

[0065] In formula (a-1-m), M a Represents a polymerizable group. Examples of the polymerizable group include (meth)acrylate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, (meth)acrylamide and free radical polymerizable groups of its derivatives, and siloxane. Preferably, (meth)acrylate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, and acrylamide are used.

[0066] r is an integer satisfying 1≤r≤3.

[0067] In formula (a-1-m), M b It is a group selected from a single bond, a (r+1)-valent heterocycle, a linear or branched alkyl group having 1 to 10 carbon atoms, a (r+1)-valent aromatic group, and a (r+1)-valent alicyclic group, each of which is unsubstituted or one or more hydrogen atoms are optionally substituted by a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group.

[0068] As A1, A2 and M b The aromatic group in the formula (A) includes aromatic hydrocarbons having 6 to 18 carbon atoms such as benzene, biphenyl, and naphthalene. b The alicyclic group in the formula (A1, A2 and M) includes alicyclic hydrocarbons having 6 to 12 carbon atoms such as cyclohexane and bicyclohexane. b Examples of the heterocyclic ring in A1 and A2 include nitrogen-containing heterocyclic rings such as pyridine, piperidine, and piperazine. Examples of the alkyl group in A1 and A2 include linear or branched alkyl groups having 1 to 10 carbon atoms.

[0069] From the viewpoint of being able to show good vertical orientation control ability and stable pretilt angle, as the structure of (a-1), the group shown in the above (pa-1) or the group shown in the following (pa-1-a) can be listed. In addition, the structure derived from the monomer shown in the following formula (pa-1-ma) can be listed in this part, but it is not limited to this.

[0070]

[0071] In the formula (pa-1-a) or (pa-1-ma), M a 、M b and S a Same as above definition.

[0072] Z is an oxygen atom or a sulfur atom.

[0073] X a and X b Each is independently a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group having 1 to 3 carbon atoms.

[0074] R1 is a single bond, an oxygen atom, -COO- or -OCO-.

[0075] R2 is a divalent aromatic group, a divalent alicyclic group or a divalent heterocyclic group.

[0076] R3 is a single bond, an oxygen atom, -COO- or -OCO-.

[0077] R4 is a linear or branched alkyl group having 1 to 40 carbon atoms or a monovalent organic group having 3 to 40 carbon atoms including an alicyclic group.

[0078] R5 is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom or a cyano group, and is preferably a methyl group, a methoxy group or a fluorine atom.

[0079] a is an integer of 0-3, and b is an integer of 0-4.

[0080] In the formula (pa-1-a) or (pa-1-ma), S a The straight chain or branched alkylene group having 1 to 10 carbon atoms is preferably a straight chain or branched alkylene group having 1 to 8 carbon atoms, and preferably, for example, methylene, ethylene, n-propylene, n-butylene, tert-butylene, n-pentylene, n-hexylene, n-heptylene, and n-octylene.

[0081] As S a Examples of the divalent aromatic group include 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, and 2,3,5,6-tetrafluoro-1,4-phenylene.

[0082] As S a Examples of the divalent alicyclic group include trans-1,4-cyclohexylene and trans-trans-1,4-bicyclohexylene.

[0083] As S a Examples of the divalent heterocyclic group include 1,4-pyridylene, 2,5-pyridylene, 1,4-furanylene, 1,4-piperazinyl and 1,4-piperidinyl groups.

[0084] S a An alkylene group having 1 to 8 carbon atoms is preferred, an alkylene group having 1 to 6 carbon atoms is more preferred, and an alkylene group having 1 to 4 carbon atoms is further preferred.

[0085] Examples of the divalent aromatic group for R2 include 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2,3,5,6-tetrafluoro-1,4-phenylene, and naphthylene.

[0086] Examples of the divalent alicyclic group for R2 include trans-1,4-cyclohexylene and trans-trans-1,4-bicyclohexylene.

[0087] Examples of the divalent heterocyclic group for R2 include 1,4-pyridylene, 2,5-pyridylene, 1,4-furanylene, 1,4-piperazinyl, and 1,4-piperidinyl.

[0088] R2 may be 1,4-phenylene, trans-1,4-cyclohexylene, or trans-trans-1,4-bicyclohexylene.

[0089] Examples of the linear or branched alkyl group having 1 to 40 carbon atoms represented by R4 include linear or branched alkyl groups having 1 to 20 carbon atoms, in which a part or all of the hydrogen atoms may be substituted with fluorine atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-lauryl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 4,4,4-trifluorobutyl, 4,4,5,5,5-pentafluoropentyl, 4,4,5,5,6,6,6-heptafluorohexyl, 3,3,4,4,5,5,5-heptafluoropentyl, 2,2,2-trifluoroethyl, 2,2,3,3,3-pentafluoropropyl, 2-(perfluorobutyl)ethyl, 2-(perfluorooctyl)ethyl, and 2-(perfluorodecyl)ethyl.

[0090] Examples of the monovalent organic group having 3 to 40 carbon atoms and containing an alicyclic group as R4 include a cholestenyl group, a cholestanyl group, an adamantyl group, a group represented by the following formula (Alc-1) or (Alc-2) (wherein R7 is a hydrogen atom, a fluorine atom or an alkyl group having 1 to 20 carbon atoms, the alkyl group having 1 to 20 carbon atoms may be optionally substituted by a fluorine atom, and * indicates a bonding position).

[0091]

[0092] The monomer represented by the above formula (pa-1-ma) includes structures represented by formulas (paa-1-ma1) to (paa-1-ma18), but is not limited thereto. It should be noted that in the formula, "E" represents the E form, and "t" represents that the cyclohexyl group is trans.

[0093]

[0094]

[0095] [Thermal crosslinking group A and thermal crosslinking group B]

[0096] The thermally crosslinkable group A and the thermally crosslinkable group B are each independently an organic group selected from the group consisting of a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, a group containing an epoxy portion, an oxetane group, a thiirane group, an isocyanate group and a blocked isocyanate group, and are selected in such a way that the thermally crosslinkable group A and the thermally crosslinkable group B undergo a crosslinking reaction due to heat, wherein the thermally crosslinkable group A and the thermally crosslinkable group B are optionally the same as each other.

[0097] The combination of the heat-crosslinkable group A and the heat-crosslinkable group B includes: a combination in which one is a carboxyl group and the other is an epoxy group, an oxetanyl group or a thiirane group; a combination in which one is a hydroxyl group and the other is a blocked isocyanate group; a combination in which one is a phenolic hydroxyl group and the other is an epoxy group, an oxetanyl group or a thiirane group; a combination in which one is a carboxyl group and the other is a blocked isocyanate group; a combination in which one is an amino group and the other is a blocked isocyanate group; a combination in which both are N-alkoxymethylamides, etc. More preferred combinations are a carboxyl group and an epoxy group, a hydroxyl group and a blocked isocyanate group, etc.

[0098] In order to introduce the thermally crosslinkable group A into the polymer as the component (A), a monomer having the thermally crosslinkable group A may be copolymerized.

[0099] When the liquid crystal aligning agent used in the present invention satisfies the requirement Z1, when producing the polymer as the component (A), both the monomer having the thermally crosslinkable group A and the monomer having the thermally crosslinkable group B may be copolymerized.

[0100] Examples of the monomer having a thermally crosslinkable group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, mono(2-(acryloyloxy)ethyl)phthalate, mono(2-(methacryloyloxy)ethyl)phthalate, N-(carboxyphenyl)maleimide, N-(carboxyphenyl)methacrylamide, and N-(carboxyphenyl)acrylamide.

[0101] Monomers having a hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, 2-(acryloyloxy)ethyl caprolactone, 2-(methacryloyloxy)ethyl caprolactone, poly(ethylene glycol)ethyl ether acrylate, poly(ethylene glycol)ethyl ether methacrylate, 5-acryloyloxy-6-hydroxynorbornene-2-carboxylic acid-6-lactone, and 5-methacryloyloxy-6-hydroxynorbornene-2-carboxylic acid-6-lactone;

[0102] Monomers having a phenolic hydroxyl group, such as hydroxystyrene, N-(hydroxyphenyl)methacrylamide, N-(hydroxyphenyl)acrylamide, N-(hydroxyphenyl)maleimide and N-(hydroxyphenyl)maleimide;

[0103] Monomers having an amino group such as aminoethyl acrylate, aminoethyl methacrylate, aminopropyl acrylate and aminopropyl methacrylate;

[0104] (Meth)acrylamide compounds substituted with hydroxymethyl or alkoxymethyl, such as N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide;

[0105] Monomers having a group containing an epoxy moiety such as allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, 2-methyl glycidyl methacrylate, α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α-ethyl 6,7-epoxyheptyl acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3,4-epoxycyclohexylmethyl methacrylate, 3-vinyl-7-oxabicyclo[4.1.0]heptane, 1,2-epoxy-5-hexene, and 1,7-octadiene monoepoxide;

[0106] 3-(Acryloyloxymethyl)oxetane, 3-(Acryloyloxymethyl)-2-methyloxetane, 3-(Acryloyloxymethyl)-3-ethyloxetane, 3-(Acryloyloxymethyl)-2-trifluoromethyloxetane, 3-(Acryloyloxymethyl)-2-pentafluoroethyloxetane, 3-(Acryloyloxymethyl)-2-phenyloxetane, 3-(Acryloyloxymethyl)-2,2-difluorooxetane, 3-(Acryloyloxymethyl)-2,2,4-trifluorooxetane, 3-(Acryloyloxymethyl)-2,2,4,4-tetrafluorooxetane, 3-(2-Acryloyloxyethyl)oxetane, 3-( Acrylic acid esters such as 3-(2-acryloyloxyethyl)-2-ethyloxetane, 3-(2-acryloyloxyethyl)-3-ethyloxetane, 3-(2-acryloyloxyethyl)-2-trifluoromethyloxetane, 3-(2-acryloyloxyethyl)-2-pentafluoroethyloxetane, 3-(2-acryloyloxyethyl)-2-phenyloxetane, 3-(2-acryloyloxyethyl)-2,2-difluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4-trifluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4,4-tetrafluorooxetane; 3-(methacryloyloxymethyl)oxetane, 3-(2-acryloyloxyethyl)-2-ethyloxetane, 3-(2-acryloyloxyethyl)-3-ethyloxetane, 3-(2-acryloyloxyethyl)-2-trifluoromethyloxetane, 3-(2-acryloyloxyethyl)-2-pentafluoroethyloxetane, 3-(2-acryloyloxyethyl)-2-phenyloxetane, 3-(2-acryloyloxyethyl)-2,2-difluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4-trifluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4,4-tetrafluorooxetane; (Methacryloyloxymethyl)-2-methyloxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-trifluoromethyloxetane, 3-(methacryloyloxymethyl)-2-pentafluoroethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 3-(methacryloyloxymethyl)-2,2-difluorooxetane, 3-(methacryloyloxymethyl)-2,2,4-trifluorooxetane, 3-(methacryloyloxymethyl)-2,2,4,4-tetrafluorooxetane, 3-(2-methacryloyloxyethyl)oxetane, 3-(2 Monomers having an oxetane group such as 3-(2-methacryloyloxyethyl)-2-ethyloxetane, 3-(2-methacryloyloxyethyl)-3-ethyloxetane, 3-(2-methacryloyloxyethyl)-2-trifluoromethyloxetane, 3-(2-methacryloyloxyethyl)-2-pentafluoroethyloxetane, 3-(2-methacryloyloxyethyl)-2-phenyloxetane, 3-(2-methacryloyloxyethyl)-2,2-difluorooxetane, 3-(2-methacryloyloxyethyl)-2,2,4-trifluorooxetane, and 3-(2-methacryloyloxyethyl)-2,2,4,4-tetrafluorooxetane;

[0107] Monomers having a thiirane group such as 2,3-cyclothiopropyl acrylate or 2,3-cyclothiopropyl methacrylate, and 2-, 3-, or 4-(β-cyclothiopropylthiomethyl)styrene, 2-, 3-, or 4-(β-cyclothiopropyloxymethyl)styrene, 2-, 3-, or 4-(β-cyclothiopropylthio)styrene, and 2-, 3-, or 4-(β-cyclothiopropyloxy)styrene;

[0108] Monomers having a blocked isocyanate group such as 2-(0-(1'-methylpropylideneamino)carboxyamino)ethyl acrylate, 2-(3,5-dimethylpyrazolyl)carbonylamino)ethyl acrylate, 2-(0-(1'-methylpropylideneamino)carboxyamino)ethyl methacrylate, and 2-(3,5-dimethylpyrazolyl)carbonylamino)ethyl methacrylate. It should be noted that (meth)acrylamide refers to both acrylamide and methacrylamide.

[0109] Furthermore, in the present invention, when obtaining a specific copolymer, in addition to using a monomer having a photo-alignment group represented by the above formula (a-1-m) and a monomer having a thermally crosslinkable group A and, if necessary, a thermally crosslinkable group B, other monomers copolymerizable with these monomers may also be used in combination.

[0110] Specific examples of such other monomers include acrylate compounds, methacrylate compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, acrylamide and other acrylamide compounds, and monomers having a nitrogen-containing aromatic heterocyclic group and a polymerizable group.

[0111] Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthracene acrylate, anthracenyl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecanyl acrylate, and 8-ethyl-8-tricyclodecanyl acrylate.

[0112] Examples of the methacrylate compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthracene methacrylate, anthracenyl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecanyl methacrylate, and 8-ethyl-8-tricyclodecanyl methacrylate.

[0113] Examples of the (meth)acrylic acid amide compound include acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide.

[0114] Examples of the vinyl compound include methyl vinyl ether, benzyl vinyl ether, vinyl naphthalene, vinyl carbazole, allyl glycidyl ether, and 3-vinyl-7-oxabicyclo[4.1.0]heptane.

[0115] Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, and bromostyrene.

[0116] Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

[0117] The nitrogen-containing aromatic heterocyclic ring may be an aromatic cyclic hydrocarbon containing at least one, preferably one to four, structures selected from the group consisting of the following formulae [Na] to [Nb] (wherein Z2 is a linear or branched alkyl group having 1 to 5 carbon atoms).

[0118]

[0119] Specifically, oxazole ring, thiazole ring, pyridine ring, pyrimidine ring, quinoline ring, 1-pyrazoline ring, isoquinoline ring, thiadiazole ring, pyridazine ring, triazine ring, pyrazine ring, o-phenanthroline ring, quinoxaline ring, benzothiazole ring, oxadiazole ring, acridine ring etc. can be listed. Furthermore, the carbon atoms of these nitrogen-containing aromatic heterocyclic rings optionally have a substituent containing a heteroatom. Among these, for example, pyridine ring can be listed.

[0120] Examples of the monomer having a nitrogen-containing aromatic heterocyclic group and a polymerizable group include 2-(2-pyridylcarbonyloxy)ethyl (meth)acrylate, 2-(3-pyridylcarbonyloxy)ethyl (meth)acrylate, and 2-(4-pyridylcarbonyloxy)ethyl (meth)acrylate.

[0121] The other monomers used in the present invention may be used alone or in combination of two or more.

[0122] The photoreactive site represented by the above formula (pa-1) contained in the polymer of the present invention may be used alone or in combination of two or more.

[0123] The photoreactive site represented by the formula (pa-1) is preferably contained in a ratio of 5 to 50 mol %, 10 to 40 mol % or 15 to 35 mol % of all repeating units of the polymer as the component (A).

[0124] The site having a thermally crosslinkable group contained in the polymer of the present invention may be a site containing the thermally crosslinkable group A alone, or may be a site containing two or more thermally crosslinkable groups A and thermally crosslinkable groups B in combination.

[0125] The amount of the site having a thermally crosslinkable group introduced is preferably 50 to 95 mol%, 60 to 90 mol%, or 65 to 85 mol% of all repeating units of the polymer as the component (A).

[0126] The content of the structure derived from the other monomer is preferably 0 to 40 mol%, 0 to 30 mol%, or 0 to 20 mol% of all repeating units of the polymer as the component (A).

[0127] <Method for producing specific polymer>

[0128] The specific polymer of the component (A) contained in the liquid crystal aligning agent of the present invention can be obtained by copolymerizing a monomer having a photo-alignment group represented by the above formula (pa-1), a monomer having the above thermal crosslinking group A, and a monomer having the above thermal crosslinking group B as desired. In addition, it can be copolymerized with the above other monomers.

[0129] The manufacturing method of the specific polymer of (A) component in the present invention is not particularly limited, and the general method used in industry can be utilized. Specifically, it can be manufactured by cationic polymerization, free radical polymerization, and anionic polymerization utilizing the vinyl group of the monomer. Among these, free radical polymerization is particularly preferred from the viewpoints of the ease of reaction control, etc.

[0130] As the polymerization initiator for radical polymerization, known compounds such as radical polymerization initiators and reversible addition-fragmentation chain transfer (RAFT) polymerization agents can be used.

[0131] The free radical thermal polymerization initiator is a compound that generates free radicals by heating to a temperature above the decomposition temperature. Examples of such free radical thermal polymerization initiators include ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (hydrogen peroxide, tert-butyl hydroperoxide, isopropylbenzene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, diisopropylbenzene peroxide, dilauroyl peroxide, etc.), peroxyketals (dibutyl peroxide cyclohexane, etc.), alkyl peresters (tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, tert-amyl peroxy-2-ethylcyclohexanoate, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), and azo compounds (azobisisobutyronitrile and 2,2'-bis(2-hydroxyethyl)azobisisobutyronitrile, etc.).

[0132] Such radical thermal polymerization initiators may be used alone or in combination of two or more.

[0133] The free radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates free radical polymerization by light irradiation. As such free radical photopolymerization initiators, known compounds such as benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, and isopropylxanthone can be listed. These compounds can be used alone or in combination of two or more.

[0134] The radical polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, etc. can be used.

[0135] The solvent used in the polymerization reaction of the specific polymer as component (A) is not particularly limited as long as it is a solvent in which the generated polymer dissolves. Specific examples include solvents described in the <Solvent> section below, such as N-alkyl-2-pyrrolidones, dialkyl imidazoles, lactones, carbonates, ketones, compounds represented by formula (Sv-1) and compounds represented by formula (Sv-2), tetrahydrofuran, 1,4-dioxane, dimethyl sulfone, dimethyl sulfoxide, etc.

[0136] These solvents may be used alone or in combination. Furthermore, even a solvent that does not dissolve the generated polymer may be mixed with the above solvents to the extent that the generated polymer does not precipitate.

[0137] In radical polymerization, oxygen in the solvent may inhibit the polymerization reaction, and therefore, it is preferred to use an organic solvent that has been degassed as much as possible.

[0138] The polymerization temperature during free radical polymerization can be selected from any temperature in the range of 30 to 150° C., preferably in the range of 50 to 100° C. In addition, the reaction can be carried out at any concentration, and the monomer concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration in the initial stage, and then an organic solvent can be added.

[0139] In the above-mentioned free radical polymerization reaction, if the ratio of the free radical polymerization initiator is large relative to the monomer, the molecular weight of the obtained polymer becomes small, and if it is small, the molecular weight of the obtained polymer becomes large. Therefore, the ratio of the free radical initiator is preferably 0.1 to 10 mol% relative to the polymerized monomer. In addition, various monomer components, solvents, initiators, etc. can also be added during polymerization.

[0140] [Polymer recovery]

[0141] When the polymer generated is recovered from the reaction solution obtained by the above reaction, it is sufficient to put the reaction solution into a poor solvent to precipitate these polymers. As the poor solvent used for precipitation, methanol, acetone, hexane, heptane, butyl cellosolve, heptane, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, water, etc. can be listed. After the polymer that has been put into the poor solvent and precipitated is filtered and recovered, it can be dried at room temperature or heated under normal pressure or reduced pressure. In addition, if the operation of re-dissolving the precipitated polymer in an organic solvent and re-precipitating and recovering is repeated 2 to 10 times, the impurities in the polymer can be reduced. As the poor solvent at this time, for example, alcohols, ketones, hydrocarbons, etc. can be listed. If more than 3 poor solvents selected from them are used, the purification efficiency is further improved, so it is preferred.

[0142] The molecular weight of the specific polymer of the component (A) is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000, as measured by GPC (gel permeation chromatography), taking into account the strength of the resulting coating film, workability during coating film formation, and coating film uniformity.

[0143] <(B) Component>

[0144] When the liquid crystal aligning agent used for this invention satisfies requirement Z2, a crosslinking agent is contained as (B) component. As (B) component, the crosslinking agent which has two or more heat crosslinkable groups B is mentioned.

[0145] Examples of the crosslinking agent as component (B) include low molecular weight compounds such as epoxy compounds, compounds having two or more amino groups, methylol compounds, isocyanate compounds, phenolic plastic compounds, and blocked isocyanate compounds; and polymers such as polymers of N-alkoxymethyl acrylamide, polymers of compounds having epoxy groups, and polymers of compounds having isocyanate groups.

[0146] Specific examples of the epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N',-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane.

[0147] Examples of the compound having two or more amino groups include diamines such as alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, and aliphatic diamines.

[0148] As an example of alicyclic diamines, 1, 4- diaminocyclohexane, 1, 3- diaminocyclohexane, 4, 4'- diaminodicyclohexylmethane, 4, 4'- diamino-3, 3'- dimethyldicyclohexylamine, isophoronediamine, etc. are mentioned.

[0149] Examples of the aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino-2-methoxybenzene, 2,5-diamino-p-xylene, and 1,3-diamino-4-chlorobenzene.

[0150] Examples of the aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3-(3-aminopropyl)aniline, 4-(3-aminopropyl)aniline, 3-(3-methylaminopropyl)aniline, 4-(3-methylaminopropyl)aniline, 3-(4- aniline, 3-(5-aminopentyl)aniline, 4-(5-aminopentyl)aniline, 3-(5-methylaminopentyl)aniline, 4-(5-methylaminopentyl)aniline, 2-(6-aminonaphthyl)methylamine, 3-(6-aminonaphthyl)methylamine, 2-(6-aminonaphthyl)ethylamine, 3-(6-aminonaphthyl)ethylamine, and the like.

[0151] Examples of the aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, and 1,9-diamino-5-methylheptane.

[0152] Specific examples of the methylol compound include compounds such as alkoxymethylated glycoluril, alkoxymethylated benzoguanamine, and alkoxymethylated melamine.

[0153] Specific examples of the alkoxymethylated glycoluril include 1,3,4,6-tetrakis(methoxymethyl)glycoluril, 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, 1,1,3,3-tetrakis(methoxymethyl)urea, 1,3-bis(hydroxymethyl)-4,5-dihydroxy-2-imidazolidinone, and 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolidinone. Commercially available products include glycoluril compounds manufactured by Mitsui SAITECH (trade names: CYMEL (registered trademark) 1170, POWDERLINK (registered trademark) 1174), methylated urea resins (trade names: UFR (registered trademark) 65), butylated urea resins (trade names: UFR (registered trademark) 300, U-VAN10S60, U-VAN10R, U-VAN11HV), and urea / formaldehyde resins manufactured by DIC Corporation (highly condensed type, trade names: BECKAMINE (registered trademark) J-300S, BECKAMINE P-955, BECKAMINE N).

[0154] Specific examples of alkoxymethylated benzoguanamine include tetramethoxymethylbenzoguanamine, etc. Commercially available products include those manufactured by Mitsui SAITECH (trade name: CYMEL (registered trademark) 1123) and Sanwa Chemical Co., Ltd. (trade names: NIKALAC (registered trademark) BX-4000, NIKALAC BX-37, NIKALAC BL-60, NIKALAC BX-55H).

[0155] Specific examples of the alkoxymethylated melamine include hexamethoxymethylmelamine. Examples of commercially available products include methoxymethyl-type melamine compounds (trade names: CYMEL (registered trademark) 300, CYMEL 301, CYMEL 303, CYMEL 350) manufactured by Mitsui SAITECH Co., Ltd., butoxymethyl-type melamine compounds (trade names: MICOAT (registered trademark) 506, MICOAT 508), methoxymethyl-type melamine compounds (trade names: NIKALAC (registered trademark) MW-30, NIKALAC MW-22, NIKALAC MW-11, NIKALAC MS-001, NIKALAC MX-002, NIKALAC MX-730, NIKALAC MX-750, NIKALAC MX-035) manufactured by Sanwa Chemical Co., Ltd., butoxymethyl-type melamine compounds (trade names: NIKALAC (registered trademark) MX-45, NIKALAC MX-410, NIKALAC MX-302) etc.

[0156] In addition, it may be a compound obtained by condensing a melamine compound, a urea compound, a glycoluril compound, and a benzoguanamine compound in which the hydrogen atom of the amino group is replaced by a hydroxymethyl group or an alkoxymethyl group. Examples include high molecular weight compounds produced from melamine compounds and benzoguanamine compounds as described in U.S. Patent No. 6,323,310. Commercially available products of the aforementioned melamine compound include trade names: CYMEL (registered trademark) 303 (manufactured by Mitsui SAITECH Co., Ltd.), and commercially available products of the aforementioned benzoguanamine compound include trade names: CYMEL (registered trademark) 1123 (manufactured by Mitsui SAITECH Co., Ltd.).

[0157] Specific examples of the isocyanate compound include VESTANAT B1358 / 100, VESTAGON BF1540 (isocyanurate modified polyisocyanates, manufactured by Degussa Japan Co., Ltd.), TAKENATE (registered trademark) B-882N, and TAKENATE B-7075 (isocyanurate modified polyisocyanates, manufactured by Mitsui Chemicals, Inc.).

[0158] Specific examples of the phenolic plastic compound include the following compounds, but the phenolic plastic compound is not limited to the following compound examples.

[0159]

[0160] Specific examples of the compound having two or more hydroxyalkylamide groups at the molecular terminal include the following compounds, Primid XL-552, and Primid SF-4510.

[0161]

[0162] Examples of the blocked isocyanate compound include CORONATE AP STABLE M, CORONATE 2503, 2515, 2507, 2513, 2555, and MILLIONATE MS-50 (all manufactured by Nippon Polyurethane Industries, Ltd.), and TAKENATE B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals, Inc.).

[0163] Furthermore, examples of the polymer of N-alkoxymethyl acrylamide include polymers produced using acrylamide compounds or methacrylamide compounds substituted with a hydroxymethyl group or an alkoxymethyl group, such as N-hydroxymethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, and N-butoxymethyl (meth) acrylamide.

[0164] Specific examples of such polymers include poly(N-butoxymethylacrylamide), copolymers of N-butoxymethylacrylamide and styrene, copolymers of N-hydroxymethylmethacrylamide and methyl methacrylate, copolymers of N-ethoxymethylmethacrylamide and benzyl methacrylate, and copolymers of N-butoxymethylacrylamide, benzyl methacrylate and 2-hydroxypropyl methacrylate, etc. The weight average molecular weight of such polymers is 1,000 to 200,000, more preferably 3,000 to 150,000, and even more preferably 3,000 to 50,000.

[0165] Examples of the polymer of a compound having an epoxy group include polymers produced using a compound having an epoxy group such as glycidyl methacrylate and 3,4-epoxycyclohexylmethyl methacrylate.

[0166] Specific examples of such polymers include poly(3,4-epoxycyclohexylmethyl methacrylate), poly(glycidyl methacrylate), copolymers of glycidyl methacrylate and methyl methacrylate, copolymers of 3,4-epoxycyclohexylmethyl methacrylate and methyl methacrylate, copolymers of glycidyl methacrylate and styrene, etc. The weight average molecular weight of such polymers is 1,000 to 200,000, more preferably 3,000 to 150,000, and even more preferably 3,000 to 50,000.

[0167] Examples of the polymer of the compound having an isocyanate group include compounds having an isocyanate group such as 2-isocyanatoethyl methacrylate (Karenz MOI [registered trademark], manufactured by Showa Denko K.K.), 2-isocyanatoethyl acrylate (Karenz AOI [registered trademark], manufactured by Showa Denko K.K.); or polymers produced using compounds having a blocked isocyanate group such as 2-(0-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate (Karenz MOI-BM [registered trademark], manufactured by Showa Denko K.K.), 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate (Karenz MOI-BP [registered trademark], manufactured by Showa Denko K.K.).

[0168] Specific examples of such polymers include poly(2-isocyanatoethyl acrylate), poly(2-(0-[1'-methylpropylideneamino]carboxylamino)ethyl methacrylate), copolymers of 2-isocyanatoethyl methacrylate and styrene, and copolymers of 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate and methyl methacrylate. The weight average molecular weight of such polymers is 1,000 to 200,000, more preferably 3,000 to 150,000, and even more preferably 3,000 to 50,000.

[0169] These cross-linking agents can be used alone or in combination of two or more.

[0170] When the crosslinking agent of (B) component is contained in the liquid crystal aligning agent used for this invention, 1-100 mass parts is preferable based on 100 mass parts of resin which is (A) component, and 1-80 mass parts is more preferable.

[0171] [Preparation of Liquid Crystal Alignment Agent]

[0172] The liquid crystal alignment agent used in the present invention is preferably prepared as a coating liquid in order to be suitable for forming a liquid crystal alignment film. That is, the liquid crystal alignment agent of the present invention is preferably prepared as a solution obtained by dissolving a resin component for forming a resin coating in an organic solvent. Here, the resin component refers to the specific polymer as component (A) already described. At this time, the content of the specific polymer is preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, further preferably 1 to 15% by mass, and particularly preferably 1 to 10% by mass relative to the entire liquid crystal alignment agent.

[0173] <Solvent>

[0174] The solvent contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as it is a solvent that dissolves the (A) component and the (B) component as required. The solvent contained in the liquid crystal aligning agent can be one kind, or two or more kinds can be mixed and used. In addition, even if it is not a solvent that dissolves the (A) component and the (B) component, it can also be used in combination with a solvent that dissolves the (A) component and the (B) component. At this time, if the surface energy of the solvent that does not dissolve the (A) component and the (B) component is less than the solvent that dissolves the (A) component and the (B) component, the coating property of the liquid crystal aligning agent for the substrate can be improved, so it is preferred.

[0175] Specific examples include water, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and other N-alkyl-2-pyrrolidone; N,N-dimethylformamide, N,N-dimethylacetamide, N-methylcaprolactam, tetramethylurea, 3-methoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, 1,3-dimethyl-2-imidazolidinone and other dialkyl imidazolidinone; lactones such as γ-butyrolactone, γ-valerolactone, δ-valerolactone; carbonates such as ethylene carbonate and propylene carbonate; Ketones such as alcohol, ethanol, propanol, isopropanol, 3-methyl-3-methoxybutanol, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, isoamyl methyl ketone, methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, 4-hydroxy-4-methyl-2-pentanone; compounds represented by the following formula (Sv-1) and the following formula (Sv-2), 4-methyl-2-pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, 2-methylcyclohexyl acetate, butyl butyrate, isoamyl butyrate, diisobutyl carbitol, diisoamyl ether, etc.

[0176]

[0177] In formulas (Sv-1) to (Sv-2), Y1 and Y2 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, X1 is an oxygen atom or -COO-, X2 is a single bond or a carbonyl group, and R1 is an alkanediyl group having 2 to 4 carbon atoms. n1 is an integer from 1 to 3. When n1 is 2 or 3, multiple R1s may be the same or different. Z1 is a divalent hydrocarbon group having 1 to 6 carbon atoms, and Y3 and Y4 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms), etc.

[0178] In formula (Sv-1), examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms for Y1 and Y2 include monovalent chain hydrocarbon groups having 1 to 6 carbon atoms, monovalent alicyclic hydrocarbon groups having 1 to 6 carbon atoms, and monovalent aromatic hydrocarbon groups having 1 to 6 carbon atoms. Examples of the monovalent chain hydrocarbon group having 1 to 6 carbon atoms include alkyl groups having 1 to 6 carbon atoms. The alkanediyl group for R1 may be linear or branched.

[0179] In the formula (Sv-2), examples of the divalent hydrocarbon group having 1 to 6 carbon atoms represented by Z1 include an alkanediyl group having 1 to 6 carbon atoms.

[0180] Examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms for Y3 and Y4 include monovalent chain hydrocarbon groups having 1 to 6 carbon atoms, monovalent alicyclic hydrocarbon groups having 1 to 6 carbon atoms, and monovalent aromatic hydrocarbon groups having 1 to 6 carbon atoms. Examples of the monovalent chain hydrocarbon group having 1 to 6 carbon atoms include alkyl groups having 1 to 6 carbon atoms.

[0181] Specific examples of the solvent represented by formula (Sv-1) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monohexyl ether, ethylene glycol dimethyl ether, ethylene glycol monoacetate, ethylene glycol diacetate, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, propylene glycol diacetate, ethylene glycol, 1,4-butanediol, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, and the like;

[0182] Specific examples of the solvent represented by (Sv-2) include methyl glycolate, ethyl glycolate, butyl glycolate, ethyl lactate, butyl lactate, isoamyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, and butyl 3-methoxypropionate.

[0183] The boiling point of the solvent is preferably 80 to 200° C., more preferably 80 to 180° C., and preferred solvents include N,N-dimethylformamide, tetramethylurea, 3-methoxy-N,N-dimethylpropionamide, propanol, isopropanol, 3-methyl-3-methoxybutanol, ethyl amyl ketone, methyl ethyl ketone, isoamyl methyl ketone, methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-pentyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, 2-methylcyclohexyl acetate, butyl butyrate, isoamyl butyrate, diisobutyl carbitol, diisoamyl ether, ethylene glycol monomethyl ether, ethyl Glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monoacetate, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, 3-methoxybutyl acetate, methyl glycolate, ethyl glycolate, butyl glycolate, ethyl lactate, butyl lactate, isopentyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, and the like.

[0184] The boiling point being within the above range is preferred particularly when the liquid crystal aligning agent containing the above solvent is applied onto a plastic substrate described later.

[0185] <Other ingredients>

[0186] The liquid crystal aligning agent used in the present invention may contain other components in addition to the above-mentioned (A) component and (B) component. As such other components, crosslinking catalysts, compounds that improve the uniformity of film thickness and / or surface smoothness when coated with the liquid crystal aligning agent, compounds that improve the adhesion between the liquid crystal aligning film and the substrate, etc. can be listed, but are not limited to this.

[0187] <Crosslinking Catalyst>

[0188] In the liquid crystal alignment agent used in the present invention, a crosslinking catalyst may be added for the purpose of promoting the reaction between the thermally crosslinkable group A and the thermally crosslinkable group B. Examples of such crosslinking catalysts include p-toluenesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, p-phenolsulfonic acid, 2-naphthalenesulfonic acid, mesitylenesulfonic acid, p-xylene-2-sulfonic acid, m-xylene-2-sulfonic acid, 4-ethylbenzenesulfonic acid, 1H,1H,2H,2H-perfluorooctanesulfonic acid, perfluoro(2-ethoxyethane)sulfonic acid, pentafluoroethanesulfonic acid, nonafluorobutane-1-sulfonic acid, dodecylbenzenesulfonic acid and other sulfonic acids or their hydrates, salts and the like. Examples of the compound that generates an acid by heat include bis(toluenesulfonyloxy)ethane, bis(toluenesulfonyloxy)propane, bis(toluenesulfonyloxy)butane, p-nitrobenzyl toluenesulfonate, o-nitrobenzyl toluenesulfonate, 1,2,3-phenylenetri(methylsulfonate), pyridinium p-toluenesulfonate, morpholinium p-toluenesulfonate, ethyl p-toluenesulfonate, propyl p-toluenesulfonate, butyl p-toluenesulfonate, isobutyl p-toluenesulfonate, methyl p-toluenesulfonate, phenylethyl p-toluenesulfonate, cyanomethyl p-toluenesulfonate, 2,2,2-trifluoroethyl p-toluenesulfonate, 2-hydroxybutyl p-toluenesulfonate, and N-ethyl p-toluenesulfonamide.

[0189] [Compounds for improving uniformity of film thickness and / or surface smoothness]

[0190] Examples of the compound that improves uniformity of film thickness and / or surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

[0191] Specific examples include Eftop (registered trademark) 301, EF303, and EF352 (manufactured by Tohkem Products Co., Ltd.), Megafac (registered trademark) F171, F173, and R-30 (manufactured by DIC Corporation), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Co., Ltd.), AsahiGuard (registered trademark) AG710 (manufactured by Asahi Glass Co., Ltd.), and Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by AGC SEIMI Chemical Co., Ltd.).

[0192] The usage ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the resin component contained in the polymer composition.

[0193] [Compound for Improving Adhesion Between Liquid Crystal Alignment Film and Substrate]

[0194] As a specific example of the compound which improves the adhesiveness of a liquid crystal aligning film and a substrate, the functional silane-containing compound shown below etc. are mentioned.

[0195] 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-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxy Amino silane-containing compounds include 1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, and N-bis(oxyethylene)-3-aminopropyltriethoxysilane.

[0196] When a compound that improves adhesion to a substrate is used, the amount thereof used is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the resin component contained in the polymer composition.

[0197] In one embodiment, in order to improve the photoreactivity of the photo-alignment group, a photosensitizer may be used as an additive, and specific examples thereof include aromatic 2-hydroxyketones (benzophenones), coumarin, ketocoumarin, carbonyl dicoumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal.

[0198] In the liquid crystal aligning agent used in the present invention, the aforementioned resin component may be all the aforementioned specific polymers, or may be mixed with other polymers other than these (hereinafter also referred to as "other polymers"). In this case, the content of other polymers in the resin component may be 5 to 95 parts by mass or 10 to 90 parts by mass relative to 100 parts by mass of the total of component (A) and other polymers.

[0199] Examples of such other polymers include polymers that do not satisfy at least one of the essential features of the above-mentioned specific polymers, such as poly(meth)acrylates, polyamic acids, polyamic acid esters, and polyimides.

[0200] As the other polymer, preferably polyimide and its precursor (hereinafter also referred to as polyimide component), it is a polymer having a surface energy close to the polymer as (A) component. Acrylic components such as (A) component are basically low in polarity and low in surface energy. On the other hand, the polarity of the polyimide component is high and the surface energy is high. However, if the difference in the surface energy of these two components is too large, the following problems may occur: aggregation occurs due to the lack of smooth compatibility, thereby forming a film with concave and convex, or the process margin is narrowed due to repulsion and unevenness. Therefore, by reducing the polarity of the polyimide component, although the surface energy will be higher than that of the acrylic component, it can be controlled to a value with a small difference. As a method for reducing the polarity of the polyimide component, there is a method of mixing with the (A) component after chemical imidization and a method of introducing side chains.

[0201] As such polymers, there can be listed: polymers obtained by chemically imidizing a tetracarboxylic acid derivative such as a known tetracarboxylic dianhydride and a known diamine after polymerization, polyimide precursors obtained by using diamines having side chains, polyimides obtained by imidizing them, polyimide precursors obtained by using diamines having tert-butoxycarbonyloxy groups, polyimides obtained by imidizing them, etc. By such side chains and chemical imidization, the surface energy can be made close to the acrylic polymer as the (A) component, so that when the liquid crystal aligning agent is applied and fired to form a cured film, aggregation does not occur, and a flat cured film can be given. As diamines having side chains, diamines represented by formulas (2), (3), (4), and (5) described in paragraphs

[0023] to

[0039] of International Patent Application Publication WO2016 / 125870 and diamines represented by formulas [A-1] to [A-32] as specific examples thereof can be listed. Examples of the diamine having a tert-butoxycarbonyloxy group include diamines having structures of formulae [A-1], [A-2], and [A-3] described in paragraphs

[0011] to

[0034] of International Patent Application Publication WO2017 / 119461 and diamines exemplified as specific examples thereof.

[0202] <Liquid crystal alignment film and liquid crystal display element>

[0203] The liquid crystal alignment agent of the present invention can be coated on a substrate and fired, and then oriented by rubbing treatment, light irradiation, etc. to form a liquid crystal alignment film, or can be formed into a liquid crystal alignment film without orientation treatment in some vertical orientation applications. As a substrate, glass such as float glass and soda glass can be used; transparent substrates formed of plastics such as polyethylene terephthalate, polybutylene terephthalate, polypropylene, polystyrene, polyether sulfone, polycarbonate, poly (alicyclic olefin), polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF), polyether sulfone (PES), polyamide, polyimide, acrylic and cellulose triacetate can be used.

[0204] As the transparent conductive film provided on one side of the substrate, a NESA film (registered trademark of PPG, USA) containing tin oxide (SnO 2 ), an ITO film containing indium oxide-tin oxide (In 2 O 3 —SnO 2 ), or the like can be used.

[0205] <Coating Film Forming Step>

[0206] The coating method of the liquid crystal alignment agent of the present invention is not particularly limited, and there are screen printing, flexographic printing, offset printing, inkjet, dip coating, roller coating, slit coating, spin coating, etc., which can be used according to the purpose. After coating on the substrate by these methods, the solvent is evaporated by heating means such as a heating plate to form a coating film.

[0207] The firing after applying the liquid crystal alignment agent can be performed at any temperature of 40 to 300° C., preferably 40 to 250° C., more preferably 40 to 230° C. When a transparent substrate formed of a plastic substrate is used, it is preferably 40 to 150° C., more preferably 80 to 140° C. The firing time is preferably 0.1 to 15 minutes, more preferably 1 to 10 minutes.

[0208] The thickness of the coating film formed on the substrate is preferably 5 to 1,000 nm, more preferably 10 to 500 nm or 10 to 300 nm. The calcination can be performed using a hot plate, a hot air circulation furnace, an infrared furnace, or the like.

[0209] <Light irradiation step>

[0210] The light irradiation step in the present invention includes the following steps in sequence: a first irradiation step of irradiating the cured film obtained in the aforementioned coating film forming step with ultraviolet rays from an oblique direction; and a second irradiation step of irradiating the cured film after the ultraviolet irradiation with ultraviolet rays from a direction different from that in the first irradiation step, and at least one of the first irradiation step and the second irradiation step is performed through a mask including a light-shielding area and a non-light-shielding area.

[0211] As the light irradiated in the alignment treatment based on light irradiation, for example, ultraviolet rays including light with a wavelength of 150 to 800 nm, visible light, etc. can be listed. Among these, ultraviolet rays including light with a wavelength of 300 to 400 nm are preferred. The irradiation light may be polarized light or non-polarized light. As polarized light, light including linearly polarized light is preferably used.

[0212] The irradiation dose of light is preferably set to 0.1 mJ / cm 2 Above and less than 1,000mJ / cm 2 , more preferably 1 to 500 mJ / cm 2 , and more preferably 2 to 200 mJ / cm 2 .

[0213] The irradiation direction of ultraviolet rays is usually 1° to 89°, preferably 20° to 70°, and particularly preferably 30° to 60° relative to the substrate normal. If the angle is too small, the pretilt angle becomes small, and if it is too large, it becomes difficult to design the irradiation device.

[0214] As a method of adjusting the irradiation direction to the above angle, there are a method of tilting the substrate itself and a method of tilting the light source. However, from the viewpoint of productivity, tilting the light source itself is more preferable.

[0215] It should be noted that the present invention can use a specific composition to cancel the pretilt angle formed by ultraviolet rays irradiated from a certain direction by ultraviolet rays irradiated from another direction, thereby forming a different pretilt angle.

[0216] Thus, by, for example, forming a pretilt angle in a specific direction by full-surface exposure to ultraviolet light, and then irradiating ultraviolet light from other directions through a mask, a plurality of regions with different orientation directions (orientation division) can be easily formed, and a multi-domain liquid crystal display element can be efficiently manufactured.

[0217] In the multi-domain liquid crystal alignment film obtained by the manufacturing method of the present invention, the pretilt angle preferably has a region 1 tilted from 90° by minus 0.1° to minus 10° and a region 2 tilted from 90° by plus 0.1° to plus 10°, as a pretilt angle suitable for the vertical alignment mode. That is, as the pretilt angle, it is preferred to have a region 1 of 80° to 89.9° and a region 2 of 90.1° to 100°, and it is further preferred to have a region 1 of 85° to 89° and a region 2 of 91° to 95°.

[0218] It should be noted that when forming the above-mentioned region 1 and region 2, region 1 may be formed by the first irradiation process and region 2 may be formed by the second irradiation process, or region 2 may be formed by the first irradiation process and region 1 may be formed by the second irradiation process. When the first irradiation process is performed without a mask, the light irradiation amount in the second irradiation process is preferably greater than the light irradiation amount in the first irradiation process. On the other hand, when the first irradiation process is performed with a mask, the light irradiation amount in the second irradiation process is preferably less than the light irradiation amount in the first irradiation process.

[0219] According to the present invention, when a patterned mask is used in both the first irradiation process and the second irradiation process, even if the mask is offset, the inclination angle of the first irradiation area can be eliminated in the second irradiation area and replaced with the inclination angle based on the second irradiation. Therefore, when the mask is offset, no "dark line" will be formed.

[0220] The liquid crystal display element of the present invention can use the multi-domain liquid crystal alignment film obtained in the present invention, and is made using a common method, and its preparation method is not particularly limited. The above-mentioned pair of substrates are opposed across an appropriate gap, and for the purpose of making the thickness of the liquid crystal sandwiched between the substrates uniform, it is preferred to configure a spacer between the substrates. As the spacer, in addition to using the known spacer materials such as the spacer formed by the photosensitive spacer formation composition, the concave-convex formed on the layer formed by the liquid crystal cured product can also be used as a spacer.

[0221] <Liquid crystal clamping process>

[0222] Regarding the formation of a liquid crystal unit by sandwiching a liquid crystal between substrates, for example, the following two methods can be cited. As a first method, the following method can be cited: a pair of substrates are arranged oppositely with a gap (cell gap) between them in a manner that the liquid crystal alignment films are opposite to each other, the peripheral portions of the pair of substrates are adhered using a sealant, and after the liquid crystal is injected into the cell gap divided by the substrate surface and the appropriate sealant, the injection hole is sealed, thereby manufacturing a liquid crystal unit.

[0223] As a second method, the following method (One Drop Fill (ODF) method) can be listed: a UV-curable sealing material, for example, is applied to a specified portion on one of two substrates on which a liquid crystal alignment film is formed, and then liquid crystal is dropped at specified locations on the surface of the liquid crystal alignment film. Then, the other substrate is attached so that the liquid crystal alignment film faces the other substrate, and the liquid crystal is pushed toward the entire surface of the substrate to spread it, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal unit.

[0224] As liquid crystals, fluorine-based liquid crystals, cyano-based liquid crystals, or liquid crystal compounds or liquid crystal compositions that are polymerized by at least one of heating and light irradiation (hereinafter also referred to as polymerizable liquid crystals or curable liquid crystal compositions) can be used, which have positive or negative dielectric constant anisotropy depending on the application.

[0225] In one embodiment, the step of forming the coating film of the liquid crystal aligning agent may be performed by a roll-to-roll method. If the roll-to-roll method is used, the manufacturing process of the liquid crystal display element can be simplified, thereby reducing the manufacturing cost.

[0226] Furthermore, by attaching polarizing plates to both outer surfaces of the liquid crystal cell, a liquid crystal display element can be obtained.

[0227] As the polarizing plate used on the outside of the liquid crystal unit, there are listed: a polarizing plate obtained by sandwiching a polarizing film called "H film" with a cellulose acetate protective film, or a polarizing plate composed of the H film itself. The polarizing film called "H film" is obtained by stretching and orienting polyvinyl alcohol while allowing it to absorb iodine.

[0228] The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention as described above has good liquid crystal alignment, is excellent in pretilt angle expression ability, and can obtain high reliability. In addition, the liquid crystal display element manufactured by the method of the present invention has excellent display characteristics.

[0229] Example

[0230] The structures of the compounds used in Examples are shown below.

[0231] It should be noted that, in the formula, "t" indicates that the cyclohexyl group is trans.

[0232]

[0233] MA-1, MA-2, MA-3, and MA-4 are photo-alignment monomers, and CR-1, CR-2, MOI-BP, HEMA, and MAA are thermal crosslinking monomers.

[0234]

[0235] X-1, X-2 and X-3 are tetracarboxylic dianhydride monomers.

[0236]

[0237] X-4 is a side chain diamine monomer, and X-5 and X-6 are other diamine monomers.

[0238] The abbreviations of the organic solvents used in Examples and the like are shown below.

[0239] PGME: Propylene glycol monomethyl ether

[0240] CHN: Cyclohexanone

[0241] The abbreviations of the polymerization initiators used in Examples and the like are as follows.

[0242] AIBN: 2,2'-azobisisobutyronitrile

[0243] <Polymer Molecular Weight Determination>

[0244] The molecular weight of the polymer in the synthesis example was measured as follows using a room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific and columns (KD-803 and KD-805) manufactured by Shodex.

[0245] Column temperature: 50°C

[0246] Eluent: DMF (as additives, lithium bromide monohydrate (LiBr·H2O) 30mmol / L, phosphoric acid·anhydrous crystals (orthophosphoric acid) 30mmol / L, THF 10ml / L)

[0247] Flow rate: 1.0ml / min

[0248] Standard samples for preparing the calibration curve: TSK standard polyethylene oxide manufactured by Tosoh Corporation (molecular weights of about 9,000,000, 150,000, 100,000, and 30,000) and polyethylene glycol manufactured by Polymer Laboratories (molecular weights of about 12,000, 4,000, and 1,000).

[0249] <Reference Example 1>

[0250] MA-1 (4.95 g, 12.0 mmol) and MOI-BP (7.04 g, 28.0 mmol) were dissolved in CHN (69.8 g), degassed with a diaphragm pump, and then AIBN (0.33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55°C for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (A). The number average molecular weight of the polymer was 44,200 and the weight average molecular weight was 141,800.

[0251] To the obtained methacrylate polymer powder (A) (1.5 g), CHN (18.0 g) was added and dissolved by stirring at room temperature for 5 hours. CR-1 (0.15 g) and PGME (18.0 g) were added to the solution and stirred to obtain a liquid crystal aligning agent (A1).

[0252] <Example 1-0>

[0253] [Fabrication of Liquid Crystal Cell]

[0254] The liquid crystal alignment agent (A1) obtained by reference example 1 was spin-coated on the ITO surface of a glass substrate with a transparent electrode formed of an ITO film, and dried for 300 seconds on a 40°C hot plate. Then, it was calcined for 10 minutes on a 120°C hot plate to form a liquid crystal alignment film with a film thickness of 100 nm. Thereafter, the coating surface of the alignment film was irradiated with 50 mJ / cm2 at an angle of 40° from the normal direction of the substrate through a polarizing plate. 2 The irradiation intensity is 4.3mW / cm 2 The 313 nm linearly polarized ultraviolet light to be irradiated is taken out by passing the ultraviolet light emitted from the high pressure mercury lamp through a 313 nm band pass filter and a Brewster polarizing plate.

[0255] Two of the above substrates were prepared, and after 4 μm spacer beads were scattered on the liquid crystal alignment film of one substrate, a sealant (XN-1500T manufactured by Mitsui Chemicals, Inc.) was applied. Next, the other substrate was attached in a manner that the liquid crystal alignment film faces were opposite and the irradiation direction of the incident polarized ultraviolet light was 180° relative to the irradiation direction of the ultraviolet light incident on the opposing substrate, and the sealant was thermally cured at 120°C for 90 minutes to prepare an empty cell. A negative liquid crystal (MLC-3022 manufactured by MERCK Co., Ltd.) was injected into the empty cell by a reduced pressure injection method to prepare a liquid crystal cell.

[0256] [Evaluation of pretilt angle]

[0257] The pretilt angle of the liquid crystal cell was measured by the Mueller Matrix method using "AxoScan" manufactured by Axo Metrix. The results are summarized in Table 1.

[0258] [Evaluation of Liquid Crystal Orientation]

[0259] After the liquid crystal cell was prepared, an isotropic phase treatment was performed at 120° C. for 1 hour, and the cell was observed using a polarizing microscope. The orientation was considered good if there was no poor orientation such as light leakage or domain generation, or if uniform liquid crystal drive was obtained when a voltage was applied to the liquid crystal cell. The results are summarized in Table 1.

[0260] <Example 1-1>

[0261] In the [Fabrication of Liquid Crystal Cell] of Example 1-0, 50 mJ / cm 2 After the linearly polarized ultraviolet rays were applied, 50 mJ / cm 2 The liquid crystal unit was obtained by the same method as in Example 1-0 except that the first irradiation and the second irradiation were tilted 40° in opposite directions from the normal direction. In addition, the pretilt angle and the orientation of the liquid crystal unit were evaluated by the same method as in Example 1-0.

[0262] <Examples 1-2, 1-3>

[0263] In [Fabrication of Liquid Crystal Cell] of Example 1-1, the second polarized ultraviolet irradiation dose was changed to 100 mJ / cm 2 (Example 1-2), 150mJ / cm 2 (Example 1-3) Except for this, a liquid crystal cell was obtained by the same method as in Example 1-1. Furthermore, the pretilt angle and the alignment of the liquid crystal cell were evaluated by the same method as in Example 1-0.

[0264] <Reference Example 2>

[0265] MA-1 (4.95 g, 12.0 mmol), MOI-BP (3.52 g, 14.0 mmol), and HEMA (1.82 g, 14.0 mmol) were dissolved in CHN (60.2 g), degassed using a diaphragm pump, and then AIBN (0.33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55°C for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (B). The number average molecular weight of the polymer is 33,800 and the weight average molecular weight is 123,500.

[0266] CHN (18.0 g) was added to the obtained methacrylate polymer powder (B) (1.5 g), and it was stirred at room temperature for 5 hours and dissolved. PGME (18.0 g) was added to this solution, and it stirred, and obtained the liquid crystal aligning agent (B1).

[0267] <Reference Example 3>

[0268] MA-1 (3.30 g, 8.0 mmol) and MAA (2.75 g, 32.0 mmol) were dissolved in CHN (36.2 g), degassed with a diaphragm pump, and then AIBN (0.33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55°C for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (C). The number average molecular weight of the polymer was 51,500 and the weight average molecular weight was 143,000.

[0269] To the obtained methacrylate polymer powder (C) (1.5 g), CHN (18.0 g) was added and dissolved by stirring at room temperature for 5 hours. CR-2 (0.45 g) and PGME (18.0 g) were added to the solution and stirred to obtain a liquid crystal aligning agent (C1).

[0270] <Reference Example 4>

[0271] X-4 (2.28 g, 3.00 mmol), X-5 (1.22 g, 4.00 mmol), X-6 (1.45 g, 3.00 mmol) and X-1 (2.23 g, 6.00 mmol) were dissolved in NMP (27.2 g), reacted at 60°C for 5 hours, then X-2 (1.00 g, 2.00 mmol), X-3 (0.87 g, 2.00 mmol) and NMP (9.1 g) were added, and reacted at 40°C for 10 hours to obtain a polyamic acid polymer solution.

[0272] After adding NMP to the polyamic acid polymer solution (50g) and diluting it to 6.5% by mass, acetic anhydride (8.8g) and pyridine (2.7g) were added as imidization catalysts, and the mixture was reacted at 75°C for 2.5 hours. The reaction solution was put into methanol (700ml), and the obtained precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain a polyimide polymer powder. The imidization rate of the polyimide polymer was 71%, the number average molecular weight was 13000, and the weight average molecular weight was 42000.

[0273] NMP (44.0 g) was added to the obtained polyimide powder (6.0 g), and it was stirred at 70° C. for 20 hours to dissolve. NMP (10.0 g) and BCS (40.0 g) were added to the solution, and it was stirred at room temperature for 5 hours to obtain a polyimide polymer solution (H1).

[0274] The obtained polyimide polymer solution (H1) (14.0 g) and the liquid crystal aligning agent (B1) (6.0 g) obtained in Reference Example 2 were stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (D1).

[0275] <Reference Example 5>

[0276] The polyimide polymer solution (H1) (14.0 g) obtained in Reference Example (4) and the liquid crystal aligning agent (C1) (6.0 g) obtained in Reference Example 3 were stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (E1).

[0277] <Examples 2-0 to 5-3>

[0278] The test was carried out in the same manner as in Examples 1-0 to 1-3, except that the liquid crystal aligning agent described in Table 1 was used instead of the liquid crystal aligning agent (A1) obtained in Reference Example 1. The evaluation results are described in Table 1.

[0279] <Reference Example 6>

[0280] MA-2 (13.74 g, 24.0 mmol) and MA-3 (7.02 g, 16.0 mmol) were dissolved in CHN (119.5 g), degassed with a diaphragm pump, and then AIBN (0.33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40° C. to obtain a methacrylate polymer powder (D). The number average molecular weight of the polymer is 35,700 and the weight average molecular weight is 126,000.

[0281] CHN (18.0 g) was added to the obtained methacrylate polymer powder (D) (1.5 g), and it was stirred at room temperature for 5 hours and dissolved. By adding CHN (18.0 g) to this solution and stirring, a liquid crystal aligning agent (F1) was obtained.

[0282] <Comparative Example 1-0>

[0283] [Fabrication of Liquid Crystal Cell]

[0284] The liquid crystal alignment agent (F1) obtained in Reference Example 6 was spin-coated on the ITO surface of a glass substrate with a transparent electrode formed of an ITO film, and dried for 300 seconds on a 40°C hot plate to form a liquid crystal alignment film with a film thickness of 100 nm. The coating surface was irradiated with 50 mJ / cm2 at an angle of 40° from the normal direction of the substrate through a polarizing plate. 2 The irradiation intensity is 4.3mW / cm 2 313nm linearly polarized ultraviolet light. Then, it was calcined on a heating plate at 120°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. The incident linearly polarized UV light was prepared by passing the ultraviolet light from a high-pressure mercury lamp through a 313nm bandpass filter and then through a 313nm polarizing plate.

[0285] Two of the above substrates were prepared, and after 4 μm spacer beads were spread on the liquid crystal alignment film of one substrate, a sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was applied. Next, the other substrate was attached in a manner that the liquid crystal alignment film faces were opposite and the orientation direction reached 180°, and the sealant was thermally cured at 120°C for 90 minutes to prepare an empty cell. A negative liquid crystal (MLC-3022 manufactured by MERCK Co., Ltd.) was injected into the empty cell by a reduced pressure injection method to prepare a liquid crystal cell.

[0286] Furthermore, the pretilt angle and the liquid crystal cell alignment were evaluated by the same method as in Example 1-0.

[0287] <Comparative Example 1-1>

[0288] In the [Fabrication of Liquid Crystal Cell] of Comparative Example 1-0, 50 mJ / cm 2 After the linearly polarized ultraviolet rays were applied, 50 mJ / cm 2 The liquid crystal unit was obtained by the same method as in Comparative Example 1-0 except that the first irradiation and the second irradiation were tilted 40° in opposite directions from the normal direction. In addition, the pretilt angle and the orientation of the liquid crystal unit were evaluated by the same method as in Example 1-0.

[0289] <Comparative Examples 1-2, 1-3>

[0290] In the [Production of Liquid Crystal Cell] of Comparative Example 1-0, the second polarized ultraviolet irradiation dose was changed to 100 mJ / cm 2 (Comparative Example 1-2), 150mJ / cm 2 (Comparative Example 1-3) Except for this, a liquid crystal cell was obtained in the same manner as in Comparative Example 1. Furthermore, the pretilt angle and the alignment of the liquid crystal cell were evaluated in the same manner as in Example 1-0.

[0291] <Reference Example 7>

[0292] MA-2 (17.18 g, 30.0 mmol) and MAA (1.72 g, 20.0 mmol) were dissolved in NMP (108.51 g), degassed with a diaphragm pump, and then AIBN (0.25 g, 1.5 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55°C for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (E). The number average molecular weight of the polymer was 22700 and the weight average molecular weight was 131000.

[0293] CHN (18.0 g) was added to the obtained methacrylate polymer powder (E) (1.5 g), and it was stirred at room temperature for 5 hours and dissolved. By adding CHN (18.0 g) to this solution and stirring, a liquid crystal aligning agent (G1) was obtained.

[0294] <Comparative Examples 2-0 to 2-3>

[0295] The test was carried out in the same manner as in Comparative Examples 1-0 to 1-3, except that the calcining temperature was changed from 120°C to 150°C, using the liquid crystal aligning agent (G1) obtained in Reference Example 7.

[0296] <Reference Example 8>

[0297] MA-4 (4.05 g, 8.0 mmol) and MAA (2.75 g, 32.0 mmol) were dissolved in CHN (28.5 g), degassed with a diaphragm pump, and then AIBN (0.33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a polymer solution of methacrylate. The polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5 / 5, and the obtained precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40° C. to obtain a methacrylate polymer powder (H). The number average molecular weight of the polymer was 47,000 and the weight average molecular weight was 140,000.

[0298] To the obtained methacrylate polymer powder (H) (1.5 g) was added CHN (18.0 g), and the mixture was stirred at room temperature for 5 hours to dissolve. To the solution was added CR-2 (0.45 g) and PGME (18.0 g), and the mixture was stirred to obtain a liquid crystal aligning agent (I1).

[0299] <Reference Example 9>

[0300] A liquid crystal aligning agent (J1) was obtained by stirring the polyimide polymer solution (H1) (14.0 g) obtained in Reference Example (4) and the liquid crystal aligning agent (I1) (6.0 g) obtained in Reference Example (8) at room temperature for 5 hours.

[0301] <Examples 6-0 to 7-3>

[0302] The test was carried out in the same manner as in Examples 1-0 to 1-3, except that the liquid crystal aligning agent described in Table 2 was used instead of the liquid crystal aligning agent (A1) obtained in Reference Example 1. The evaluation results are described in Table 2.

[0303] [Table 1]

[0304] Table 1.

[0305]

[0306] [Table 2]

[0307] Table 2.

[0308]

[0309] As is clear from Tables 1 and 2, the tilt angle can be changed by performing the second irradiation in all Examples, and the orientation of the liquid crystal after the change is also good. On the other hand, the tilt angle cannot be changed in all Comparative Examples.

[0310] Industrial Applicability

[0311] According to the manufacturing method of this invention, a multi-domain liquid crystal alignment film can be manufactured efficiently. Moreover, the liquid crystal display element using the obtained multi-domain liquid crystal alignment film can be suitably used for liquid crystal display elements for ECB, etc.< / x> < / x>

Claims

1. A method for manufacturing a multi-domain liquid crystal alignment film, characterized in that: The method comprises the following steps in sequence: A process of applying a liquid crystal alignment agent on a substrate and forming a cured film by drying and firing; a first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction to form a pretilt angle; and a second irradiation step of irradiating the cured film after ultraviolet irradiation obtained in the first irradiation step with ultraviolet light from a direction different from the irradiation direction in the first irradiation step, thereby forming a pretilt angle different from the pretilt angle formed by the first irradiation, At least one of the first irradiation step and the second irradiation step is performed through a mask including a light-shielding region and a non-light-shielding region, thereby obtaining a liquid crystal alignment film having a plurality of regions with different alignment directions. The liquid crystal aligning agent contains a solvent and (A) a polymer having a photo-aligning group represented by the following formula (pa-1) and a thermally crosslinkable group A. ， In the formula (pa-1), A represents a pyrimidine-2,5-diyl group, a pyridine-2,5-diyl group, a 2,5-thiophenylene group, a 2,5-furanyl group, a 1,4-naphthylene group or a phenylene group, or a 2,6-naphthylene group or a phenylene group, which is optionally substituted with a group selected from fluorine, chlorine and cyano groups, or optionally substituted with an alkoxy group having 1 to 5 carbon atoms, or a linear or branched alkyl residue, wherein the alkoxy group having 1 to 5 carbon atoms is optionally substituted with one cyano group or one or more halogen atoms, and the linear The straight-chain or branched alkyl residue may be optionally substituted by one cyano group or one or more halogen atoms as appropriate; R1 is a single bond, an oxygen atom, -COO- or -OCO-; R2 is a divalent aromatic group, a divalent alicyclic group, a divalent heterocyclic group or a divalent condensed ring group; R3 is a single bond, an oxygen atom, -COO- or -OCO-; R4 is a straight-chain or branched alkyl group having 1 to 40 carbon atoms or a monovalent organic group having 3 to 40 carbon atoms including an alicyclic group; D represents an oxygen atom, a sulfur atom or -NR d -, where R d represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; X and Y are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group having 1 to 3 carbon atoms; a is an integer of 0 to 3; * represents a bonding position, And the liquid crystal alignment agent satisfies the following Z1 and / or Z2: Z1: The (A) polymer further has a thermally crosslinkable group B; Z2: further contains (B) a compound having two or more thermally crosslinkable groups B in its molecule, Among them, the thermally crosslinkable group A and the thermally crosslinkable group B are each independently a group selected from the group consisting of a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, a group containing an epoxy portion, an oxetane group, a thiirane group, an isocyanate group and a blocked isocyanate group, and are selected in a manner such that the thermally crosslinkable group A and the thermally crosslinkable group B undergo a crosslinking reaction due to heat, wherein the thermally crosslinkable group A and the thermally crosslinkable group B are optionally the same as each other.

2. The method according to claim 1, wherein: At least one of the ultraviolet rays irradiated in the first irradiation step and the second irradiation step is polarized ultraviolet rays.

3. The method according to claim 1, wherein: Only the second irradiation step is performed through the mask.

4. The method according to claim 3, wherein: The irradiation amount of ultraviolet rays in the second irradiation step is greater than the irradiation amount of ultraviolet rays in the first irradiation step.

5. The method according to claim 1, wherein: Only the first irradiation step is performed through the mask.

6. The method according to claim 5, wherein: The irradiation amount of ultraviolet rays in the second irradiation step is smaller than the irradiation amount of ultraviolet rays in the first irradiation step. 7 . A multi-domain liquid crystal alignment film, formed using the method according to claim 1 . 8 . A liquid crystal display element comprising the multi-domain liquid crystal alignment film according to claim 7 .

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