Definitions

• the present disclosure relates to a method for manufacturing a liquid crystal alignment film and a liquid crystal element.
• the liquid crystal element has a liquid crystal alignment film for aligning liquid crystal molecules.
• a liquid crystal alignment film for aligning liquid crystal molecules.
• demands for display performance of liquid crystal panels have become more severe with the expansion of usage and usage environment.
• various studies have been made on liquid crystal alignment films for improving various characteristics of the liquid crystal panel (see, for example, Patent Documents 1 and 2).
• Patent Document 1 discloses a photo-alignment method with high mass productivity in an in-plane switching mode or the like.
• Patent Document 2 discloses that a photo-alignment liquid crystal aligning agent obtained using a diamine having a specific structure as a raw material exhibits good characteristics in the vertical alignment mode.
• a lower tilt angle is required to lower the pretilt angle than the conventional one in order to improve luminance reduction with higher definition.
• ⁇ tilt is a pretilt angle difference before and after voltage application when a voltage is applied to the liquid crystal element for a predetermined time (for example, several to several tens of hours).
• the present disclosure has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a liquid crystal alignment film that can achieve both a low tilt angle and a ⁇ tilt characteristic in a vertical alignment type liquid crystal element.
• the following means are provided. ⁇ 1> [I] The process of apply
• R 1 is a photo-alignment group
• R 2 is a group in which at least one hydrogen atom bonded to a carbon atom of an alkyl group having 1 to 40 carbon atoms is substituted with a halogen atom, * is a bond, is there.
• ⁇ 2> The method for producing a liquid crystal alignment film according to ⁇ 1>, wherein the heating temperature of the coated surface is 160 ° C. or higher.
• ⁇ 3> The method for producing a liquid crystal alignment film according to ⁇ 1>, wherein the heating temperature of the coated surface is 180 ° C. or higher.
• a liquid crystal device comprising a liquid crystal alignment film obtained by the manufacturing method according to any one of the above items ⁇ 1> to ⁇ 3>.
• the method for producing a liquid crystal alignment film of the present disclosure includes a step of applying a liquid crystal aligning agent on a substrate and then irradiating the application surface with polarized radiation, and further heating the application surface during irradiation with polarized radiation or after irradiation with polarized radiation. To do. Specifically, the production method includes the following steps [0] to [II].
• Step [0]: Preparation step] This step is a step of preparing a liquid crystal aligning agent for forming a liquid crystal alignment film on the substrate.
• a liquid crystal aligning agent a polymer having a partial structure represented by the following formula (1) (hereinafter also referred to as a specific polymer) and other additives optionally blended as necessary are contained in the solvent. A composition dissolved in is used.
• the liquid crystal aligning agent is for forming an alignment film having a vertical alignment ability.
• R 1 is a photo-alignment group
• R 2 is a group in which at least one hydrogen atom bonded to a carbon atom of an alkyl group having 1 to 40 carbon atoms is substituted with a halogen atom, * is a bond, is there.
• the specific polymer has a partial structure represented by the above formula (1) in the side chain.
• the group represented by “—R 1 —” in the above formula (1) is a photo-alignment group, and examples thereof include an azobenzene-containing group, a cinnamic acid structure-containing group, a chalcone-containing group, a benzophenone-containing group, and a coumarin-containing group. It is done. Among these, a cinnamic acid structure-containing group is preferable in terms of high photosensitivity and easy introduction into a side chain.
• R 1 is a cinnamic acid structure-containing group
• the partial structure represented by the above formula (1) is a group represented by the following formula (cn-1) or a group represented by the following formula (cn-2) It is particularly preferred.
• R 12 represents a phenylene group, a biphenylene group, a terphenylene group, or a cyclohexylene group, or at least a part of hydrogen atoms of these groups is a halogen atom or a carbon number of 1 to 10
• a 11 is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, —CH ⁇ CH— , —NH—, * 1 —COO—, * 1 —OCO—, * 1 —NH—CO—, * 1 —CO—NH
• R 13 is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a cyano group.
• 5 and R 6 are each independently a hydrogen atom Halogen atom, .
• X 1 is a cyano group or a monovalent organic group, an oxygen atom or -NR 4 - (provided that, R 4 is a hydrogen atom, a hydroxyl group or a monovalent organic group, R 4 is other group A may be a ring structure together with a nitrogen atom, and a is an integer of 0 to 3, and b is an integer of 0 to 4.
• R 12 when b is 2 or more, a plurality of R 12 , A 11 and R 13 may be the same or different, X 3 is a single bond or an oxygen atom, R 2 has the same meaning as in the above formula (1), and “*” is a bond. It shows that there is.)
• R 15 is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a cyano group.
• a 12 is an oxygen atom, * 1 —COO -, * 1 -OCO -, * 1 -NH-CO- or * 1 -CO-NH - (.
• R 16 is a C1- 6 is an alkanediyl group, a phenylene group or a cyclohexylene group, wherein R 5 and R 6 are each independently a hydrogen atom, a halogen atom, a cyano group or a monovalent organic group, and X 1 is an oxygen atom or —NR 4 — (wherein R 4 is a hydrogen atom, a hydroxyl group or a monovalent organic group, and R 4 may be bonded to another group to form a ring structure with the nitrogen atom).
• R 21 and R 22 are each independently a substituted or unsubstituted phenylene group or A cyclohexylene group black
• X 4 is a single bond or a divalent linking group, c is 0 or 1, d is an integer of 0 to 4, and e is an integer of 0 to 2, provided that d for but 2 or more, plural R 15 may be the same or different and when e is 2, a plurality of X 2, R 22 is optionally be the same or different .
• X 5 is A single bond or an oxygen atom, R 2 has the same meaning as in formula (1) above, and “*” represents a bond.
• the monovalent organic group represented by R 4 is preferably a hydrocarbon group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.
• the divalent linking group for X 4 include an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, —CH ⁇ CH—, —NH—, * 3 —COO—, * 3 —OCO—, * 3 —NH—CO—, * 3 —CO—NH—, * 3 —O—CH 2 —, * 3 —CH 2 —O— (“* 3 ” represents a bond to R 16 ), etc.
• * 3 —COO— is preferable.
• the group represented by “—R 2 ” in the above formula (1) is a group in which at least one hydrogen atom bonded to a carbon atom of an alkyl group having 1 to 40 carbon atoms is substituted with a halogen atom.
• R 2 is preferably a linear or branched alkyl halide group having 1 to 20 carbon atoms, and the halogen atom is preferably a fluorine atom.
• R 2 has preferably 2 or more halogen atoms, more preferably 3 or more, and further preferably 3 to 7 halogen atoms.
• R 2 is more preferably a linear or branched fluoroalkyl group having 1 to 16 carbon atoms.
• R 2 is more preferably a linear fluoroalkyl group having 2 to 12 carbon atoms in terms of achieving a better balance between low tilt angle and ⁇ tilt characteristics.
• the groups shown are preferred.
• * -R 21 -R 22 (2) (Wherein R 21 is a linear alkanediyl group having 1 to 11 carbon atoms, R 22 is a linear fluoroalkyl group having 1 to 3 carbon atoms, and * is a bond bonded to R 1. ) However, the total number of carbon atoms of R 21 and R 22 is 12 or less.)
• R 21 preferably has 2 to 11 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 3 to 10 carbon atoms.
• R 22 is preferably a perfluoroalkyl group having 1 to 3 carbon atoms, and particularly preferably a perfluoroalkyl group having 1 or 2 carbon atoms.
• the total number of carbon atoms of R 21 and R 22 is preferably 2 to 10.
• R 2 include, for example, 2,2,2-trifluoroethyl group, 3,3,3-trifluoro-n-propyl group, 4,4,4-trifluoro-n-butyl group, 3 , 3,4,4,4-pentafluoro-n-butyl group, 5,5,5-trifluoro-n-pentyl group, 4,4,5,5,5-pentafluoro-n-pentyl group, 4 , 4,5,5,6,6,6-heptafluoro-n-hexyl group, 6,6,7,7,7-pentafluoro-n-heptyl group, 7,7,8,8,8-penta Fluoro-n-octyl group, 9,9,9-trifluoro-n-nonyl group, 8,8,9,9,9-pentafluoro-n-nonyl group, 10,10,10-trifluoro-n- Decyl group and the like, and 4,4,4
• the type of the main skeleton of the specific polymer is not particularly limited, but from the viewpoint of affinity with liquid crystal and mechanical strength, a polymer of a monomer having a polymerizable unsaturated bond (hereinafter referred to as “polymer (PAc ) "), At least one selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, and polyamide, and is capable of improving the voltage holding ratio and light resistance of the liquid crystal element. More preferably, it is at least one selected from the group consisting of a combination (PAc) and polyorganosiloxane, and polyorganosiloxane is particularly preferable in that the ⁇ tilt characteristic can be further improved.
• PAc polymer of a monomer having a polymerizable unsaturated bond
• the polymer (PAc) is not particularly limited as long as it has a polymerizable unsaturated bond, examples thereof include (meth) acrylic compounds, conjugated diene compounds, aromatic vinyl compounds, maleimide compounds, and the like. It is done.
• the polymer (PAc) is a polymer obtained using a monomer containing a (meth) acrylic compound, an aromatic vinyl compound, and a maleimide compound as a raw material in that the effect of improving the light resistance of the liquid crystal element is high. preferable.
• the polymer (PAc) can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator.
• the monomer to be used preferably contains a compound having a polymerizable unsaturated bond and a partial structure represented by the above formula (1) (hereinafter also referred to as monomer Ac1).
• monomer Ac2 a compound having no partial structure represented by the above formula (1)
• Examples of the monomer Ac2 include carboxyl group-containing monomers such as (meth) acrylic acid and vinyl benzoic acid; and epoxy group-containing monomers such as 3,4-epoxycyclohexylmethyl (meth) acrylate.
• the proportion of the monomer Ac1 used is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, based on the total amount of monomers used for the synthesis. preferable.
• Examples of the polymerization initiator used in the above polymerization include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4- And azo compounds such as methoxy-2,4-dimethylvaleronitrile).
• the use ratio of the polymerization initiator is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of all monomers used in the reaction.
• the polymerization is preferably performed in an organic solvent. Examples of the organic solvent used in the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, and the like.
• the reaction temperature is preferably 30 ° C. to 120 ° C., and the reaction time is preferably 1 to 36 hours.
• the amount of organic solvent used (a) should be such that the total amount of monomers (b) used in the reaction is 0.1 to 60% by mass relative to the total amount of reaction solution (a + b). Is preferred.
• the polystyrene equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer (PAc) is preferably 250 to 500,000, more preferably 500 to 100,000. More preferably, it is 1,000 to 50,000.
• a polymer (PAc) can be used individually by 1 type or in combination of 2 or more types.
• polyamic acid (A) The polyamic acid (hereinafter also referred to as "polyamic acid (A)") as the specific polymer is not particularly limited as long as it has a partial structure represented by the above formula (1).
• A polyamic acid
• at least one of a tetracarboxylic dianhydride having a partial structure represented by the above formula (1) and a diamine compound having a partial structure represented by the above formula (1) is used as a raw material. It can be obtained by polymerization used in 1. It includes a tetracarboxylic dianhydride having no partial structure represented by the above formula (1) and a diamine having a partial structure represented by the above formula (1) in that the degree of freedom in selecting monomers is high. It is preferable to use a method in which a diamine compound is reacted.
• the tetracarboxylic dianhydride and diamine compound used for the synthesis of the polyamic acid (A) may be only the tetracarboxylic dianhydride and diamine compound having a partial structure represented by the above formula (1). You may use together the tetracarboxylic dianhydride and diamine compound which do not have the partial structure represented by Formula (1).
• Such tetracarboxylic dianhydrides and diamine compounds are not particularly limited, and known tetracarboxylic dianhydrides and diamine compounds can be used.
• a carboxyl group-containing diamine is preferably used as a diamine compound having a group capable of reacting with a crosslinking group possessed by the crosslinking agent.
• the proportion of the monomer having the partial structure represented by the above formula (1) is 5 to 99 mol% based on the total amount of the monomers used for the synthesis of the polyamic acid (A).
• the content is 10 to 95 mol%.
• the polyamic acid (A) can be obtained by reacting the above tetracarboxylic dianhydride and a diamine compound together with a molecular weight modifier as necessary.
• the ratio of the tetracarboxylic dianhydride and the diamine compound used for the polyamic acid synthesis reaction is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 with respect to 1 equivalent of the amino group of the diamine compound. A ratio of ⁇ 2 equivalents is preferred.
• the molecular weight modifier examples include acid monoanhydrides such as maleic anhydride and phthalic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. It is preferable that the usage-amount of a molecular weight modifier shall be 20 mass parts or less with respect to a total of 100 mass parts of tetracarboxylic dianhydride and a diamine compound.
• the synthesis reaction of the polyamic acid (A) is preferably performed in an organic solvent.
• the reaction temperature at this time is preferably ⁇ 20 ° C. to 150 ° C., and the reaction time is preferably 0.1 to 24 hours.
• the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.
• organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, ⁇ -butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. And at least one selected from the group consisting of halogenated phenols, or a mixture of one or more of these with another organic solvent (for example, butyl cellosolve, diethylene glycol diethyl ether, etc.) preferable.
• another organic solvent for example, butyl cellosolve, diethylene glycol diethyl ether, etc.
• the amount of organic solvent used (a) should be such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by mass with respect to the total amount (a + b) of the reaction solution. Is preferred.
• a reaction solution obtained by dissolving the polyamic acid (A) is obtained. This reaction solution may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution.
• the polyamic acid ester as the specific polymer is, for example, a method of reacting the polyamic acid (A) obtained by the above synthesis reaction with an esterifying agent (for example, alcohols); a tetracarboxylic acid diester and a diamine It can be obtained by a method of reacting a compound; a method of reacting a tetracarboxylic acid diester dihalide and a diamine compound, or the like.
• the resulting polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.
• reaction solution formed by dissolving the polyamic acid ester may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid ester contained in the reaction solution. Good.
• the polyimide as the specific polymer can be obtained, for example, by dehydrating and ring-closing the polyamic acid (A) synthesized as described above to imidize.
• the polyimide may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure possessed by the polyamic acid that is the precursor, and only a part of the amic acid structure may be dehydrated and cyclized. It may be a partially imidized product in which a ring structure coexists.
• the polyimide used for the reaction preferably has an imidization ratio of 20 to 99%, more preferably 30 to 90%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage.
• the dehydration ring closure of the polyamic acid is performed, for example, by dissolving polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as necessary.
• a dehydrating agent for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used.
• the amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid.
• the dehydration ring closure catalyst for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used.
• the amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used.
• Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid.
• the reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C.
• the reaction time is preferably 1.0 to 120 hours. In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyimide.
• the solution viscosity of the polyamic acid, polyamic acid ester and polyimide as the specific polymer is preferably 10 to 800 mPa ⁇ s, and preferably 15 to 500 mPa ⁇ s when the solution has a concentration of 10% by mass. More preferably, it has a solution viscosity of s.
• the solution viscosity (mPa ⁇ s) is E type for a polymer solution having a concentration of 10% by mass prepared using a good solvent for these polymers (eg, ⁇ -butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. using a rotational viscometer.
• the weight average molecular weight (Mw) in terms of polystyrene measured by GPC of polyamic acid, polyamic acid ester and polyimide is preferably 1,000 to 500,000, more preferably 2,000 to 300,000.
• the molecular weight distribution (Mw / Mn) represented by the ratio between Mw and the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less.
• polyorganosiloxane (C) The polyorganosiloxane as the specific polymer (hereinafter also referred to as "polyorganosiloxane (C)") is not particularly limited as long as it has a partial structure represented by the above formula (1).
• the method for synthesizing the polyorganosiloxane (C) is not particularly limited. As an example, a hydrolyzable silane compound having an epoxy group is hydrolyzed and condensed with another silane compound as necessary, and then a carboxylic acid having a partial structure represented by the above formula (1) is obtained. The method of making it react is mentioned.
• silane compound having an epoxy group examples include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like.
• Other silane compounds are not particularly limited as long as they are hydrolyzable compounds.
• tetramethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, p-styryltrimethoxysilane, vinyltriethoxysilane, 3-mercapto Examples include propyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, and trimethoxysilylpropyl succinic anhydride.
• a silane compound may be used individually by 1 type, and may be used in combination of 2 or more type.
• the use ratio of the silane compound having an epoxy group is preferably 5 mol% or more, preferably 10 mol% or more, based on the total amount of the hydrolyzable silane compound used for the synthesis of the polyorganosiloxane (C). More preferably, it is more preferably 20 mol% or more.
• the hydrolysis / condensation reaction is performed by reacting one or more silane compounds with water, preferably in the presence of a suitable catalyst and an organic solvent.
• the amount of water used is preferably 1 to 30 mol with respect to 1 mol of the silane compound (total amount).
• the catalyst to be used include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds and the like.
• the amount of catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, and the like, but is 0.01 to 3 times the mol of the total amount of silane compounds, for example.
• the organic solvent to be used examples include hydrocarbons, ketones, esters, ethers, alcohols, and the like, and it is preferable to use a water-insoluble or poorly water-soluble organic solvent.
• the organic solvent is used in an amount of preferably 10 to 10,000 parts by mass with respect to 100 parts by mass in total of the silane compounds used in the reaction.
• the above reaction is preferably carried out by heating with an oil bath or the like. At that time, the heating temperature is preferably 130 ° C. or less, and the heating time is preferably 0.5 to 12 hours.
• the organic solvent layer separated from the reaction solution is dried with a desiccant as necessary, and then the solvent is removed to obtain an epoxy group-containing polyorganosiloxane.
• the reaction between the epoxy group-containing polyorganosiloxane and the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent.
• the ratio of the carboxylic acid used is preferably 5 mol% or more, more preferably 10 to 80 mol%, based on the epoxy group of the epoxy group-containing polyorganosiloxane.
• the proportion of the carboxylic acid having the partial structure represented by the above formula (1) is the total amount of the carboxylic acid used in the reaction. On the other hand, it is preferably 30 mol% or more, more preferably 50 mol% or more, and further preferably 70 mol% or more.
• carboxylic acid which does not have the partial structure represented by the said Formula (1) (meth) acryl group containing carboxylic acid, protected carboxyl group containing carboxylic acid, etc. are mentioned, for example.
• the catalyst for example, a known compound as a so-called curing accelerator that accelerates the reaction of an organic base or an epoxy compound can be used.
• the ratio of the catalyst used is preferably 100 parts by mass or less with respect to 100 parts by mass of the epoxy group-containing polysiloxane.
• the organic solvent to be used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone and butyl acetate.
• the organic solvent is preferably used in such a ratio that the solid content concentration is 5 to 50% by mass.
• the reaction temperature in the above reaction is preferably 0 to 200 ° C., and the reaction time is preferably 0.1 to 50 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant as necessary, and then the solvent is removed to obtain a polyorganosiloxane (C) having a photo-alignment group. Can do.
• the method for synthesizing the polyorganosiloxane (C) is not limited to the hydrolysis / condensation reaction described above.
• the polyorganosiloxane (C) may be reacted by a method in which a hydrolyzable silane compound is reacted in the presence of oxalic acid and alcohol.
• a polymerization method using a hydrolyzable silane compound having a photoalignable group as a raw material may be employed.
• the polyorganosiloxane (C) has a polystyrene-equivalent weight average molecular weight measured by GPC of preferably 500 to 1,000,000, more preferably 1,000 to 100,000, and more preferably 1, It is preferably 000 to 50,000.
• polyorganosiloxane (C) may be used individually by 1 type, and may be used in combination of 2 or more type.
• the polyamide is selected from the group consisting of endocyclic enol esters, exocyclic enol esters, endocyclic acylamide esters, exocyclic acylamide esters, and oxime esters.
• a polyamide (hereinafter, also referred to as polyamide (C)), which is a reaction product of at least one kind of heterocyclic-containing compound and a diamine compound, can be preferably used.
• An example of a reaction scheme for obtaining polyamide (C) is shown below. (In the above reaction scheme, A 1 is a divalent organic group, which may be bonded to another ring structure to form a condensed ring together with the other ring structure.
• R 31 to R 35 represents Independently, they are a hydrogen atom, a halogen atom, or a monovalent organic group having 1 or more carbon atoms, Z 0 to Z 7 are each independently a divalent organic group, and Y 2 represents the above formula (1 And a divalent organic group obtained by removing two primary amino groups from a diamine having a partial structure represented by
• the diamine compound in the synthesis of the polyamide (C), only a diamine having a partial structure represented by the above formula (1) may be used, or other diamine may be used in combination.
• the proportion of the diamine having the partial structure represented by the above formula (1) is preferably 5 mol% or more, more preferably 10 mol% or more with respect to the total amount of the diamine compound used in the synthesis. preferable.
• the weight average molecular weight (Mw) in terms of polystyrene measured by GPC of the polyamide (C) is preferably 1,000 to 300,000, more preferably 2,000 to 100,000.
• the molecular weight distribution (Mw / Mn) is preferably 5 or less, more preferably 3 or less.
• the polyamide (C) used for preparation of a liquid crystal aligning agent may be only 1 type, and may combine 2 or more types.
• the liquid crystal aligning agent of the present disclosure may contain other components other than the specific polymer.
• a polymer other than the specific polymer a compound having at least one epoxy group in the molecule, a functional silane compound, a crosslinking agent, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, A filler, a dispersing agent, a photosensitizer, etc. are mentioned.
• the blending ratio of the other components can be appropriately selected according to each compound within a range not impairing the effects of the present disclosure.
• the polymer having no photo-alignable group in the side chain (hereinafter also referred to as polymer [P]) is used together with the specific polymer in that the effect of reducing the tilt angle can be further enhanced. ) Is preferably used.
• the polymer [P] is preferably a polymer having no partial structure represented by the above formula (1).
• the main skeleton of the polymer [P] is not particularly limited, but is particularly preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.
• the blending ratio of the specific polymer is preferably 1 to 200 parts by mass with respect to 100 parts by mass of the polymer [P].
• the amount is more preferably 5 to 150 parts by mass, and further preferably 10 to 100 parts by mass.
• Polymer [P] may be used individually by 1 type, and may be used in combination of 2 or more type.
• the crosslinking agent examples include compounds having a crosslinkable group such as a (meth) acryloyl group, an alkenyl group, a vinylphenyl group, an epoxy group, an isocyanate group, a blocked isocyanate group, a carboxyl group, a protected carboxyl group, and a maleimide group. It is done.
• the number of crosslinkable groups possessed by the crosslinking agent is preferably 2 or more, and preferably 2 to 6.
• the specific polymer has a group that reacts with a cross-linkable group of the cross-linking agent in the side chain in order to reduce the tilt angle and increase the effects of ⁇ tilt angle characteristics.
• the use ratio of the crosslinking agent is preferably 0.1 to 100 parts by mass, and preferably 0.5 to 70 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the liquid crystal aligning agent. More preferred.
• organic solvent used for preparing the liquid crystal aligning agent examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, ⁇ -butyrolactone, ⁇ -butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate , Ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene Glycol ethyl ether acetate, diethylene glycol dimethyl ether,
• the solvent component of the liquid crystal aligning agent is at least one selected from the group consisting of compounds represented by the following formulas (E-1) to (E-5), and has a boiling point of 180 at 1 atm. You may use the solvent (henceforth "the specific solvent") which is below ° C. Use of a specific solvent as at least a part of the solvent component is preferable in that a liquid crystal element excellent in display characteristics can be obtained even when heating during film formation is performed at a low temperature (for example, 200 ° C. or lower).
• R 41 is an alkyl group having 1 to 4 carbon atoms or CH 3 CO—
• R 42 is an alkanediyl group having 1 to 4 carbon atoms or — (R 47 —O).
• R 47 and R 48 are each independently an alkanediyl group having 2 or 3 carbon atoms, and r is an integer of 1 to 4), and R 43 is a hydrogen atom Or an alkyl group having 1 to 4 carbon atoms.
• R 44 is an alkanediyl group having 1 to 4 carbon atoms.
• R 45 and R 46 are each independently an alkyl group having 1 to 8 carbon atoms.
• R 49 is a hydrogen atom or a hydroxyl group
• R 50 is a hydrocarbon group having 1 to 9 carbon atoms when R 49 is a hydrogen atom
• R 49 is a hydroxyl group.
• R 51 and R 52 are each independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a monovalent group having an oxygen atom between the carbon-carbon bonds.
• Specific examples of the specific solvent include, for example, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, 3-methoxy-1-butanol, ethylene glycol monomethyl as the compound represented by the above formula (E-1).
• Ether ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, etc .
• Examples of the compound represented by the formula (E-2) include cyclobutanone, cyclopentanone, and cyclohexanone
• Examples of the compound represented by the above formula (E-3) include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl- n-butylketone, methyl-n-hexylketone, di-i-butylketone, trimethylnonanone, cyclopen
• Monoalcohols such as 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol, and polyvalents such as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol Alcohol;
• Examples of the compound represented by the above formula (E-5) include partial esters of polyhydric alcohols (for example, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol)
• Partial esters of polyhydric alcohols such as monomethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monopropyl
• the content rate of a specific solvent is 20 mass% or more with respect to the whole quantity of the solvent contained in a liquid crystal aligning agent, and it is 40 mass% or more. More preferably, it is more preferably 50% by mass or more, and particularly preferably 80% by mass or more.
• the solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. It is in the range of 1 to 10% by mass. That is, the liquid crystal aligning agent is applied to the substrate surface as will be described later, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, when the solid content concentration is less than 1% by mass, the film thickness of the coating film is too small to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, it is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive, and the viscosity of the liquid crystal aligning agent increases and the applicability decreases. There is a tendency.
• Step I Step of applying liquid crystal aligning agent
• the above-mentioned liquid crystal aligning agent is applied onto the substrate, and then the coated surface is heated as necessary to form a coating film on the substrate.
• the substrate for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used.
• a NESA film (registered trademark of US PPG) made of tin oxide (SnO 2 ), an ITO film made of indium oxide-tin oxide (In 2 O 3 -SnO 2 ), etc.
• coating film means both a state in which only a part of the solvent is removed from the liquid crystal aligning agent applied on the substrate to form a liquid crystal alignment film and a state in which all of the solvent is removed. It means to include.
• preheating is preferably performed for the purpose of preventing dripping of the applied liquid crystal aligning agent.
• the prebake temperature is preferably 30 to 150 ° C.
• the prebake time is preferably 0.25 to 10 minutes.
• Step II Step of irradiating the coating film with polarized radiation
• liquid crystal alignment ability is imparted to the coating film by irradiating polarized radiation to the coated surface in which the liquid crystal aligning agent is applied to the substrate.
• the radiation for example, ultraviolet rays and visible rays including light having a wavelength of 150 to 800 nm can be used.
• it is an ultraviolet ray containing light having a wavelength of 200 to 400 nm. Irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or a combination thereof.
• a light source to be used for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used.
• Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter, a diffraction grating, or the like.
• the irradiation dose is preferably 100 to 50,000 J / m 2 , more preferably 200 to 20,000 J / m 2 .
• the coated surface is heated at least one of during irradiation of polarized radiation on the coated surface in Step II and after irradiation of polarized radiation.
• This heating is a process for removing the solvent from the coated surface, and may be hereinafter referred to as “main baking”.
• the main calcination may be performed for the purpose of thermal imidization of the amic acid structure in the polymer.
• the heating temperature at this time is preferably higher than the prebake temperature. Specifically, the temperature is preferably 80 to 300 ° C, more preferably 160 to 250 ° C, and particularly preferably 180 to 230 ° C.
• the heating time is preferably 5 to 200 minutes, more preferably 10 to 150 minutes, and particularly preferably 15 to 120 minutes.
• Step III Construction of liquid crystal cell
• two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell can be manufactured by disposing a liquid crystal between the two substrates disposed to face each other.
• the sealing agent include an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer.
• the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane. Liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, and cubane liquid crystal. Further, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal or the like may be added to these liquid crystals.
• a liquid crystal element is obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as necessary.
• the polarizing plate include a polarizing plate comprising a polarizing film called an “H film” in which iodine is absorbed while stretching and orientation of polyvinyl alcohol is sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself.
• the liquid crystal element including the liquid crystal alignment film obtained by the manufacturing method described above can be effectively applied to various applications.
• various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, It can be used for a light control film.
• the liquid crystal element of the present disclosure can also be applied to a retardation film.
• the weight average molecular weight Mw and epoxy equivalent of the polymer were measured by the following methods.
• Weight average molecular weight Mw of the polymer From the result measured by gel permeation chromatography under the following conditions using the following apparatus, it was obtained as a polystyrene conversion value using monodisperse polystyrene as a standard substance.
• Measuring device Model “8120-GPC” manufactured by Tosoh Corporation Column: “TSKgelGRCXLII” manufactured by Tosoh Corporation Solvent: Tetrahydrofuran or N, N-dimethylformamide solution containing lithium bromide and phosphoric acid Sample concentration: 5% by weight Sample injection volume: 100 ⁇ L Column temperature: 40 ° C Column pressure: 68 kgf / cm 2 [Epoxy equivalent]: Measured according to “hydrochloric acid-methyl ethyl ketone method” of JIS C2105.
• EPS-1 a polymer (EPS-1) was obtained as a viscous transparent liquid.
• EPS-1 a polymer (EPS-1) was obtained as a viscous transparent liquid.
• ⁇ chemical shift
• ⁇ 3.2 ppm according to the theoretical intensity. It was confirmed that no side reaction occurred.
• the polymer (EPS-1) had a weight average molecular weight of 2,200 and an epoxy equivalent of 186 g / mol.
• Synthesis Example 1-2 In Synthesis Example 1-1, except that 1.0 g of the compound represented by the above formula (m-1) and 10.4 g of the compound represented by the following formula (m-2) were used as the carboxylic acid, Synthesis Example 1 By performing the same operation as in No. 1, 20.6 g of polymer (Si-2) was obtained as a white powder. This polymer (Si-2) had a weight average molecular weight Mw of 12,700.
• Synthesis Example 1-4 In Synthesis Example 1-1, except that 14.9 g of the compound represented by the above formula (m-3) and 3.2 g of the compound represented by the following formula (m-4) were used as the carboxylic acid, Synthesis Example 1 By performing the same operation as in No. 1, 27.4 g of the polymer (Si-4) was obtained as a white powder. The weight average molecular weight Mw of this polymer (Si-4) was 15,200.
• EPS-2 a polymer (EPS-2) was obtained as a viscous transparent liquid.
• the polymer (EPS-2) had a weight average molecular weight of 3,000 and an epoxy equivalent of 248 g / mol.
• This reaction solution was concentrated under reduced pressure at 60 ° C., and further vacuum-dried, and a mixture of a compound represented by the following formula (DE-1a) and a compound represented by the following formula (DE-1b) (hereinafter referred to as DE-1a) / B.) 36.84 g was obtained.
• the resulting polymerization solution was diluted with NMP and slowly poured into methanol with stirring to solidify.
• the precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-1).
• the number average molecular weight Mn of this polymer was 11,000, and the molecular weight distribution Mw / Mn was 3.0.
• the weight average molecular weight Mw measured in terms of polystyrene by GPC was 30,000, and the molecular weight distribution Mw / Mn was 3.
• NMP N-methyl-2-pyrrolidone
• BC butyl cellosolve
• a liquid crystal aligning agent was prepared by filtering this solution through a filter having a pore diameter of 1 ⁇ m.
• liquid crystal alignment film On the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film, the liquid crystal alignment agent prepared in the above example was applied with a spinner, and prebaked on a hot plate at 80 ° C. for 1 minute. A coating film having a thickness of 0.08 ⁇ m was formed. Next, the surface of the coating film was irradiated with polarized ultraviolet light 200 J / m 2 containing a 313 nm emission line at a room temperature from a direction inclined by 40 ° from the substrate normal line using a Hg—Xe lamp and a Grand Taylor prism.
• liquid crystal display element Screen of an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 ⁇ m on the outer periphery of the surface having one liquid crystal alignment film among the substrates on which the liquid crystal alignment film is formed in (2) above
• the liquid crystal alignment film surfaces of a pair of substrates are made to face each other, and pressure-bonded so that the projection direction of the optical axis of the ultraviolet rays of each substrate to the substrate surface is antiparallel, and bonded at 150 ° C. for 1 hour.
• the agent was heat cured.
• a negative liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) was filled into the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, this was heated at 150 ° C. and then gradually cooled to room temperature. Next, the polarizing plates are bonded to both outer surfaces of the substrate so that the polarization directions thereof are orthogonal to each other and form an angle of 45 ° with the projection direction of the optical axis of the liquid crystal alignment film onto the substrate surface. Thus, a liquid crystal display element was manufactured.
• MLC-6608 manufactured by Merck & Co., Inc.
• pretilt angle was measured for the liquid crystal display device obtained in (3) above.
• the pretilt angle is measured using a crystal using He—Ne laser light in accordance with the method described in the non-patent document “TJ Scheffer et. Al. J. Appl. Phys. Vo. 19, p. 2013 (1980)”.
• the value of the tilt angle of the liquid crystal molecules from the substrate surface was measured by the rotation method, and this was defined as the pretilt angle [°]. As a result, the pretilt angle was 87.3 °.
• the pretilt angle is 86.0 ° or more and less than 87.0 ° is “A”
• the case where it is 87.0 ° or more and less than 87.5 ° is “B”
• the case where it is 87.5 ° or more and less than 88.0 ° was “C”
• the case of 88.0 ° to less than 89.0 ° was “D”
• the case of 89.0 ° to 90.0 ° was “E”. It can be said that the lower the tilt angle, the more from E to A.
• the evaluation was impossible.
• Examples 2 to 16, Comparative Examples 1 to 4 The same solvent as in Example 1 except that the types and amounts (parts by mass) of polymer components used in the preparation of the liquid crystal aligning agent and the types and amounts (parts by mass) of additives were changed as shown in Table 1 below.
• the liquid crystal aligning agent was prepared by ratio and solid content concentration, respectively.
• Each additive in Table 1 is a compound represented by each of the following formulas (K-1) to (K-4).
• Example 1 While producing the liquid crystal display element like Example 1 except the point which changed the liquid crystal aligning agent to be used as the following Table 1, and the point which made the conditions of this baking the following Table 1.
• the pretilt angle and ⁇ tilt were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.
• the timing of the main baking is indicated as “UV irradiation”
• the irradiation with polarized radiation is performed on the hot plate several minutes after the start of the main baking, and each heating time ( The heated state was maintained until the time (minutes) of the main firing described in Table 1 below passed.
• pre-baking is performed under the same conditions as in Example 1, and then the main baking is performed without irradiation with polarized ultraviolet rays.
• a liquid crystal alignment film was formed by irradiating the coating film with polarized ultraviolet rays at room temperature.
• the liquid crystal elements of Examples 1 to 16 can achieve both a low tilt angle and a ⁇ tilt characteristic.
• Comparative Examples 1 to 4 showed a high value of the pretilt angle of 88.0% or more, and the tilt angle was not sufficiently lowered as compared with the Example.
• the ⁇ tilt characteristics were inferior to those of the Examples.

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• 2017
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