TWI545104B - Diphenylamine-based compound, a polyamic acid composition, a polyimide composition and a liquid crystal aligning agent - Google Patents

Description

Diphenylamine-based compound, polylysine composition prepared therefrom, polyimine composition, and liquid crystal alignment agent

The present invention relates to a dianiline-based compound, and more particularly to a diphenylamine-based compound containing a cyclohexyl group, a polylysine composition prepared therefrom, and a polyamidene composition, and the like A polyphthalic acid composition or a liquid crystal alignment agent of the polyimide composition.

Generally, liquid crystal displays mainly use liquid crystal molecules to rotate according to changes in an environmental electric field, thereby causing a change in light throughput and completing image display. The liquid crystal display has the advantages of small size, light weight, low power consumption and good display quality, and has become the mainstream of flat panel display in recent years.

With the expansion of the screen size, the development of liquid crystal displays has been developed to include liquid crystal display elements of thin filmed tanstor (TFT) in each pixel. In general, in a liquid crystal display device, liquid crystal molecules are placed between a pair of substrates including electrodes, and the alignment directions of the substrates are perpendicular to each other, and the arrangement of liquid crystal molecules can be controlled via a control electric field. For this type of liquid crystal display element, it is important to have an alignment of the long axis direction of the liquid crystal molecules with a uniform tilt angle of the substrate surface, and the alignment film allows the liquid crystal molecules to be aligned at a uniform pre-tilt angle.

At present, a typical method for preparing an alignment film in the industry is to apply an organic film on the surface of a substrate, and the molecules on the surface of the film are oriented by friction or other means, thereby causing the subsequently placed liquid crystal molecules to be aligned.

The polymer capable of forming the organic film may be selected from the group consisting of polyvinyl alcohol, polyethylene glycol, polyamine, polylysine or polyimine, wherein the polyimine has chemical stability and thermal stability. It is most often used as an alignment film material. Polyimine is generally obtained by polyhydrazine acid dehydration ring-closing reaction, and polylysine is obtained by reacting a diamine with a tetracarboxylic acid or a tetracarboxylic dianhydride; The nature of the alignment film is adjusted by the preparation of polyimine or polylysine or by the selection or content control of diamine and tetracarboxylic acid or tetracarboxylic dianhydride.

The diamines used to prepare the polyimine or polylysine can be mainly classified into two types: aromatic diamines or aliphatic diamines. Aromatic diamines such as:

However, when the liquid crystal alignment film made of the above diamine is applied to a liquid crystal display element, an ionic charge is generated after a voltage is applied, and an ionic charge is adsorbed by the alignment film; after a long time display, even in After the application of the voltage is stopped, it is also difficult to cause the ionic charge to be detached from the alignment film, so that it is easy to generate an afterimage on the screen. Therefore, in order to avoid the afterimage problem of the liquid crystal display element, finding a suitable diamine has become one of the goals of the industry.

Therefore, in order to improve the afterimage problem of the liquid crystal display element described above, it is an object of the present invention to provide a diphenylamine compound which is represented by the following formula (I):

In the formula (I), one of R ¹ to R ⁵ represents an amine group, one of which represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, and the other three are each selected from hydrogen , C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; one of R ⁶ to R ¹⁰ represents an amine group, one of which represents C ₁ -C ₃ alkyl or C ₁ -C ₃ The haloalkyl group and the remaining three are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents ; X ² means A represents a C ₆ -C ₄₀ divalent group containing at least one 1,4-cyclohexylene group.

A second object of the present invention is to provide a polyamido acid composition obtained by polymerizing a reaction mixture comprising at least one of the above-described diphenylamine-based compounds and at least one tetracarboxylic acid or tetracarboxylic acid. Acid dianhydride, and the polyamic acid composition has a weight average molecular weight ranging from 5,000 to 2,500,000.

A third object of the present invention is to provide a polyiminoimine composition which is obtained by subjecting the above polyamic acid composition to a dehydration ring-closure reaction.

A fourth object of the present invention is to provide a liquid crystal alignment agent comprising the above polyamic acid composition or the above polyimine composition, and a solvent.

A fifth object of the present invention is to provide a diphenylamine compound which is represented by the following formula (I):

In the formula (I), A represents The hydrogen in the above group may be optionally substituted by halogen; one of R ¹ to R ⁵ represents an amine group, one of which represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, and the rest Each of them is selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; one of R ⁶ ~ R ¹⁰ represents an amine group, one of which represents a C ₁ -C ₃ alkane a group or a C ₁ -C ₃ haloalkyl group and the other three are each selected from the group consisting of hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents ; X ² means Wherein R represents hydrogen or a C ₁ -C ₃ alkyl group.

The diphenylamine-based compound of the present invention is obtained by using a cyclohexylene group as a part of a linking group and at the same time, at least one of R ¹ to R ¹⁰ in the formula (I) is an alkyl group or a haloalkyl group. The liquid crystal display element has both a low ion density and a relatively high voltage holding ratio, and has the advantage of effectively solving the problem of residual image of the liquid crystal display element.

The first aspect of the diphenylamine compound of the present invention is represented by the following formula (I):

In the formula (I), one of R ¹ to R ⁵ represents an amine group, one of which represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, and the other three are each selected from hydrogen , C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; one of R ⁶ to R ¹⁰ represents an amine group, one of which represents C ₁ -C ₃ alkyl or C ₁ -C ₃ The haloalkyl group and the remaining three are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents ; X ² means A represents a C ₆ -C ₄₀ divalent group containing at least one 1,4-cyclohexylene group.

Preferably, the A represents 1,4-cyclohexylene, or The hydrogen in the above group may be optionally substituted by a halogen; wherein, G represents a single bond, a C ₁ -C ₂₈ alkylene group or a C ₁ -C ₂₈ extended haloalkyl group. More preferably, the G represents Wherein G ¹ and G ² each independently or differently represent a halogen, a C ₁ -C ₁₃ alkyl group or a C ₁ -C ₁₃ haloalkyl group. More preferably, G ¹ and G ² each independently or differently represent a methyl group, a halogen or a halomethyl group. In a preferred embodiment of the invention, both G ¹ and G ² represent a methyl group.

Preferably, in the formula (I), one of R ² and R ⁴ represents an amine group, and the other represents hydrogen; one of R ⁷ and R ⁹ represents an amine group, and the other represents hydrogen. And R ³ and R ⁸ each independently or differently represent a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group; and the R ¹ , R ⁵ , R ⁶ and R ¹⁰ represent hydrogen.

Preferably, the diphenylamine compound of the present invention is selected from { N , N '-(cyclohexyl-1,4-diyl) bis(3-amino-4-methylbenzamide) [ N , N '-(cyclohexane-1,4-diyl)bis( 3-amino-4-methylbenzamidle)]} or

{Bis(3-Amino-4-methylbenzoic acid) 4,4'-(propane-2,2-diyl)bis(cyclohex-4,1-diyl)ester [4,4'-( Propane-2,2-diyl)bis(cyclohexane-4,1-diyl) bis(3-amino-4-methylbenzoate)]}.

The second aspect of the diphenylamine compound of the present invention is represented by the following formula (I):

In the formula (I), A represents The hydrogen in the above group may be optionally substituted by halogen; one of R ¹ to R ⁵ represents an amine group, one of which represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, and the rest Each of them is selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; one of R ⁶ ~ R ¹⁰ represents an amine group, one of which represents a C ₁ -C ₃ alkane a group or a C ₁ -C ₃ haloalkyl group and the other three are each selected from the group consisting of hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents ; X ² means Wherein R represents hydrogen or a C ₁ -C ₃ alkyl group.

The first aspect and the second aspect of the diphenylamine-based compound of the present invention can be prepared by using the same or different known methods. Preferably, the diphenylamine compound of the present invention is obtained by reacting a monofunctional nitrobenzene compound with a bifunctional group containing a cyclohexyl group and then subjecting it to hydrogenation. More preferably, the above nitrobenzene compound and the difunctional compound are reacted in the presence of a base and an organic solvent. In the above reaction, the base has a catalytic effect, which can increase the reaction rate and lower the temperature required for the reaction.

The functionalized nitrobenzene compound can be, for example but not limited to,

The bifunctional group containing a cyclohexyl group can be, for example but not limited to,

Wherein R represents hydrogen or a C ₁ -C ₃ alkyl group.

Taking the carbonyl group represented by X ¹ and X ² in the formula (I) as an example, the preparation method of the diphenylamine compound of the present invention may, for example, be: (1) reacting a monocarboxylated nitrobenzene compound with SOCl ₂ to form a hydrazine. a chlorine-functionalized nitrobenzene compound; (2) reacting a bishydroxy compound containing a cyclohexyl group with PBr ₃ to form a dibromo compound containing a cyclohexyl group, and then reacting with Li and CuBr to form a Gilman reagent; and (3) reacting the fluorinated functionalized nitrobenzene compound with the cyclohexyl-containing Gilman reagent and hydrogenating the reaction.

Preferably, the base suitable for the above reaction may be selected from, but not limited to, a basic compound formed of a metal of Groups IA and IIA (such as a carbonate of a metal of Groups IA and IIA, etc.), a tertiary amine (such as trimethylamine, three). Ethylamine, triisopropylethylenediamine, 4-dimethylaminopyridine, etc.), or a combination thereof.

Preferably, the organic solvent suitable for the above reaction may be selected from, but not limited to, an alkyl halide (such as dichloromethane, dichloroethane, chloroform, etc.), a ketone (such as acetone, methyl ethyl ketone, etc.), tetrahydrofuran, N. -N- methyl-pyrrolidone, N , N -dimethylformamide, N , N -dimethylacetamide, dimethylhydrazine, or a combination thereof .

Preferably, in the above hydrogenation reaction, it can be carried out by a conventional hydrogenation reaction method. For example, using hydrogen or hydrazine at a suitable pressure, temperature, and a metal catalyst such as Pt, Pd, Raney-Ni, etc.; or using a reducing agent such as SnCl ₂ or Fe in the presence of concentrated hydrochloric acid; Alternatively, the reaction is carried out in an aprotic solvent using a reducing agent such as LiAlH ₄ .

The present invention also provides a polyaminic acid composition obtained by a polymerization reaction of a reaction mixture comprising at least one of the above-described diphenylamine-based compounds and at least one tetracarboxylic acid or tetracarboxylic dianhydride, and The polyamic acid composition has a weight average molecular weight ranging from 5,000 to 2,500,000.

Preferably, the tetracarboxylic acid or tetracarboxylic dianhydride suitable for the above polymerization reaction may be selected from, but not limited to, an aromatic tetracarboxylic acid (such as 1,2,4,5-benzenetetracarboxylic acid, etc.) or a dianhydride thereof. , an alicyclic tetracarboxylic acid (such as cyclobutane tetracarboxylic acid, cyclopentane tetracarboxylic acid, cyclohexane tetracarboxylic acid, etc.) or a dianhydride thereof, an aliphatic tetracarboxylic acid (such as butane tetracarboxylic acid, etc.) Or a dianhydride thereof, or a combination thereof.

Preferably, the reaction mixture may further comprise a conventional diamine compound, which may be selected from, but not limited to, an aromatic diamine [eg p-phenylenediamine, diamine diphenylmethane, diamine diphenyl ether). , 2,2-diaminophenylpropane, bis(3,5-diethyl-4-aminophenyl)methane, diamine diphenylphosphonium, diaminobenzophenone, diaminonaphthalene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)diphenylanthracene , 2,2-bis(4,4-aminophenoxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(4,4-amino group Phenoxyphenyl)hexafluoropropane, etc.], alicyclic diamine [such as bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, etc.], aliphatic Diamine [such as butanediamine, hexamethylenediamine, etc.], or a combination of these.

In the reaction mixture, the total amount of the diphenylamine compound and the conventional diamine compound is 100 mol%, and the diphenylamine compound is at least 1 mol%, preferably at least 10 mol%, more preferably at least 50. Mol%.

The polyamic acid composition obtained by the above polymerization has a polymerization degree ranging from 10 to 5,000, preferably having a polymerization degree ranging from 16 to 250; and a weight average molecular weight ranging from 5,000 to 2,500,000, and a preferred weight average molecular weight range is 8,000~125,000.

The present invention also provides a polyamidene composition obtained by subjecting the polyamic acid composition described above to a dehydration ring closure reaction.

The dehydration ring-closure reaction is carried out by heating to form a polyamidene composition by heating, and the heating temperature ranges from 100 to 350 ° C, and the preferred temperature range is from 120 to 320 ° C. The dehydration ring closure reaction has a time ranging from 3 minutes to 6 hours.

The present invention also provides a liquid crystal alignment agent comprising the above polyamic acid composition or the above polyimine composition, and a solvent.

Preferably, the solvent suitable for the above liquid crystal alignment agent may be selected from, but not limited to, N -methyl-2-pyrrolidone, m-cresol, γ-butyrolactone, N , N -dimethylacetamide, N , N -dimethylformamide, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobuthyl ether, diethylene glycol monobutyl Diethylene glycol monobuthyl ether, diethylene glycol monoethyl ether, ethyl carbitol acetate, or a combination thereof.

In order to control the subsequent coating property of the liquid crystal alignment agent and the thickness of the alignment film formed, the solid content of the liquid crystal alignment agent may be adjusted to be 3 to 10%.

The liquid crystal alignment agent of the invention is suitable for coating on a substrate by a conventional roller coating method, spin coating method or printing coating method to form a film having a thickness ranging from 0.005 to 0.5 μm, at 80 to 300 ° C. The baking is heated under the temperature range to remove the above solvent, and the polyamic acid composition can be caused to undergo a dehydration ring-closing reaction to form a polyimine composition. Preferably, the heat baking temperature ranges from 100 to 240 °C.

The invention is further described in the following examples, but it should be understood that these examples are for illustrative purposes only and are not to be construed as limiting.

<Synthesis Example 1> bis(3-amino-4-methylbenzoic acid) 4,4'-(propan-2,2-diyl)bis(cyclohex-4,1-diyl)ester (P1)

45.29 g (0.25 mol) of 4-methyl-3-nitrobenzoic acid (purchased from Acros) and 51.58 g (0.25 mol) of dicyclohexylcarbodiimide (DCC) were added to 288.46 g of tetrahydrofuran (THF). After mixing for 30 minutes, add 24.04 g (0.10 mol) of 4,4'-(propane-2,2-diyl)dicyclohexanol (purchased from Sigma-Aldrich) and 2.44 g (0.02 mol). 4-Dimethylaminopyridine (DMAP) and mixed well. After reacting for 8 hours at room temperature, the filtrate was collected by filtration and concentrated to dryness. Further, it was recrystallized and purified three times with a mixed solvent of THF and isopropyl alcohol (IPA) (THF: IPA weight ratio of 4:6), and the solid obtained by recrystallization was drained to obtain 42 g of bis (4-A). Benzyl-3-nitrobenzoic acid) 4,4'-(propane-2,2-diyl) bis(cyclohex-4,1-diyl)ester ( I1 , yield 73%) as a white solid.

28.33 g (0.05 mol) of the above compound I1 was dissolved in 152 g of THF, and 2.83 g of Pd/C and 28.33 g of 80% hydrazine were sequentially added. After reacting for 8 hours at room temperature, the filtrate was collected by filtration and concentrated to dryness. 24 g of bis(3-amino-4-methylbenzoic acid) 4,4'-(propane-2,2-diyl) bis(cyclohex-4,1-diyl) ester ( P1 , produced) The rate was 96%) white solid. ¹ H NMR (400 MHz, DMSO- d ₆ ): δ 7.23 (d, 2, Ar), 7.06 (s, 2, Ar), 7.03 (d, 2, Ar), 5.09 (s, 4, -NH _{2 )} ), 4.73 (t, 2, cyclohexane), 2.08 (s, 6, -CH ₃ ), 2.00 to 1.00 (m, 18, cyclohexane), 0.75 (s, 6, -CH ₃ ) ppm.

<Synthesis Example 2> N , N '-(Cyclohexyl-1,4-diyl)bis(3-amino-4-methylbenzamide) (P2)

Add 45.29 g (0.25 mol) of 4-methyl-3-nitrobenzoic acid and 51.58 g (0.25 mol) of DCC to 137.03 g of THF and mix well. After 30 minutes, add 11.42 g (0.10 mol) in sequence. 4-cyclohexanediamine (purchased from Acros) and 2.44 g (0.02 mol) DMAP were mixed well. After reacting for 8 hours at room temperature, the filtrate was collected by filtration and concentrated to dryness. Further, recrystallization purification was carried out three times with a mixed solvent of THF and n-hexane (THF: n-hexane weight ratio of 3:7), and the solid obtained by recrystallization was drained to obtain 24 g of N , N '- (cyclohexane). -1,4-Diyl) bis(4-methyl-3-nitrobenzamide) ( I2 , yield 56%) as a white solid.

22.02 g (0.05 mol) of the above compound I2 was dissolved in 114 g of THF, and 2.20 g of Pd/C and 22.02 g of 80% hydrazine hydrate were sequentially added. After reacting for 8 hours at room temperature, the filtrate was collected by filtration and concentrated to dryness. 17 g of N , N '-(cyclohexyl-1,4-diyl)bis(3-amino-4-methylbenzamide) ( P2 , yield 91%) was obtained as a white solid. ¹ H NMR (400 MHz, DMSO- d ₆ ): δ 77.63 (d, 2, -NH), 6.85 (d, 2, Ar), 6.73 (s, 2H, Ar), 6.60 (d, 2, Ar) , 4.88 (t, 2, cyclohexane), 2.03 (s, 6, -CH ₃ ), 2.0 to 0.5 (m, 8, cyclohexane) ppm.

<Example 1>

0.1 mol of P1 prepared in Synthesis Example 1 was dissolved in 150 mL of N -methylpyrrolidone (NMP), and 0.1 mol of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA, Daxin) was added. in the polymerization reaction, NMP was added to a solids content of 15 wt%, after 8 hours, the solids content of 15 wt% polyamide acid solution A1.

<pyr comparison example 1~5>

The synthesis steps of Comparative Examples 1 to 5 were the same as in Example 1 except that 0.1 mol of P1 obtained in Synthesis Example 1 was changed to 0.1 mol of M1 to M5 diamine compound (the structure is shown below), and the solid content was respectively obtained. 15 wt% polyaminic acid solution a1 ~ a5 .

<Application Example 1>

The polyamic acid solution A1 prepared in Example 1 was diluted to a solid content of 6.5 wt% in a mixed solvent of NMP/diethylene glycol monobutyl ether (BC) (1:1 by weight) to obtain a liquid crystal. The alignment agent B1 is coated on a glass substrate to form a thickness of 1200±100 The film was baked and heated to 230 ° C for 30 minutes, followed by directional rubbing on the film to form an alignment film. Finally, a pair of substrates on which the alignment film is formed are combined with a liquid crystal (purchased from Merck, model LCT10477) by a conventional method to obtain a liquid crystal layer containing a pair of alignment films sandwiched between the pair of alignment films and The liquid crystal display elements D1 are respectively disposed on the electrode layers of the pair of alignment films which are away from the liquid crystal layer side.

<Comparative Application Examples 1 to 5>

The process of comparing the application examples 1 to 5 was the same as that of the application example 1, except that the polyamic acid solution A1 prepared in Example 1 was changed to the polyaminic acid solutions a1 to a5 prepared in Comparative Examples 1 to 5, respectively. The liquid crystal display elements d1 to d5 are available .

<Measurement ion density>

At a temperature of 60 ° C, an alternating current of 1.5 V 0.01 Hz was applied to the pair of electrodes of the liquid crystal display element D1 of the application example 1 and the liquid crystal display elements d1 to d5 of the comparative application examples 1 to 5, respectively, and the electrodes were respectively measured. The ion density in the liquid crystal display element was as follows, and the results are summarized in Table 1 below.

<Measurement voltage retention rate>

At a temperature of 60 ° C, a direct current of 5 V was applied to the liquid crystal display elements D1 of the application example 1 and the liquid crystal display elements d1 to d5 obtained by the comparative application examples 1 to 5, respectively, and the liquid crystal display elements were respectively measured. The voltage retention rate is summarized in Table 1 below.

Comparing the results of Table 1, it is understood that the liquid crystal display element D1 obtained from the diphenylamine-based compound P1 of the present invention has a lower ion than the liquid crystal display elements d1 to d5 obtained from the diamine compounds M1 to M5 . Density (<15000 pC) and relatively high voltage holding ratio (>90%) have the advantage of effectively reducing the residual image of liquid crystal display elements.

In summary, the present invention contains a 1,4-cyclohexyl diphenylamine compound, a polylysine composition thereof, and a polyamidene composition comprising the polyamic acid composition or the poly The liquid crystal alignment agent of the quinone imine composition has the advantage of effectively solving the problem of residual image of the liquid crystal display element.

The above is only the preferred embodiment and the specific examples of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent change according to the scope of the invention and the description of the invention. And modifications are still within the scope of the invention patent.

Claims (10)

A diphenylamine compound represented by the following formula (I): In the formula (I), in R ¹ to R ⁵ , one of R ² and R ⁴ represents an amine group, and the other represents hydrogen, and one of R ¹ , R ³ and R ⁵ represents C ₁ ~ C ₃ alkyl or C ₁ -C ₃ haloalkyl, and the other two are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; in R ⁶ ~ R ¹⁰ One of R ⁷ and R ⁹ represents an amine group, the other represents hydrogen, and one of R ⁶ , R ⁸ and R ¹⁰ represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, And the other two are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents , , Or -O- ; X ² means , , Or -O- ; A represents a C ₆ -C ₄₀ divalent group containing at least one 1,4-cyclohexylene group. The diphenylamine-based compound according to claim 1, wherein the A represents 1,4-cyclohexylene, , or The hydrogen in the above group A may be optionally substituted by a halogen; wherein, G represents a single bond, a C ₁ -C ₂₈ alkylene group or a C ₁ -C ₂₈ extended haloalkyl group. The patentable scope of application of the item 2 of diphenylamine-based compound, wherein G represents the Wherein G ¹ and G ² each independently or differently represent a halogen, a C ₁ -C ₁₃ alkyl group or a C ₁ -C ₁₃ haloalkyl group. The diphenylamine-based compound according to claim 3, wherein the G ¹ and the G ² each independently or differently represent a methyl group, a halogen or a halomethyl group. The dianiline-based compound according to claim 1, wherein R ³ and R ⁸ each independently or differently represent a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group; and the R ¹ And R ⁵ , R ⁶ and R ¹⁰ represent hydrogen. The diphenylamine compound according to claim 1 of the patent application is selected from or . A polyaminic acid composition prepared by a polymerization reaction of a reaction mixture comprising at least one of the first to sixth ranges as claimed in the patent application The diphenylamine-based compound according to any one of the preceding claims, wherein at least one of the tetracarboxylic acid or the tetracarboxylic dianhydride has a weight average molecular weight ranging from 5,000 to 2,500,000. A polyamidene composition obtained by subjecting a polylysine composition as described in claim 7 of the patent to a dehydration ring closure reaction. A liquid crystal alignment agent comprising a polylysine composition as described in claim 7 or a polyamidene composition according to item 8 of the patent application, and a solvent. A diphenylamine compound represented by the following formula (I): In the formula (I), A represents or The hydrogen in the above group may be optionally substituted by halogen; in R ¹ to R ⁵ , one of R ² and R ⁴ represents an amine group, and the other represents hydrogen, and R ¹ , R ³ and R ^{5 are} One of them represents a C ₁ -C ₃ alkyl group or a C ₁ -C ₃ haloalkyl group, and the other two are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl or halogen; In R ⁶ to R ¹⁰ , one of R ⁷ and R ⁹ represents an amine group, the other represents hydrogen, and one of R ⁶ , R ⁸ and R ¹⁰ represents a C ₁ to C ₃ alkyl group or C _{1 .} ~C ₃ haloalkyl, and the other two are each selected from hydrogen, C ₁ -C ₃ alkyl, C ₁ -C ₃ alkyl or halogen; X ¹ represents , , , -O- or -NR- ; X ² means , , , -O- or -NR- ; wherein R represents hydrogen or a C ₁ -C ₃ alkyl group.