JP2019211573A - Varnish for photo-alignment film and liquid crystal display device - Google Patents

Abstract

To provide a varnish for forming a photo-alignment film that can prevent or suppress a DC afterimage and flickers in low-frequency driving in a liquid crystal display device.SOLUTION: A varnish for a photo-alignment film comprises a first polyamide acid-based compound and a second polyamide acid-based compound having higher polarity than that of the first polyamide acid-based compound in an organic solvent. The second polyamide acid-based compound is present in a larger amount than the first polyamide acid-based compound. The first polyamide acid-based compound contains: a skeleton derived from a tetracarboxylic acid compound having a cyclobutane skeleton, by 50 mol% or more; and a skeleton derived from a diamine compound having a primary amino group, a secondary amino group or a nitro group, by 10 mol% or less. The second polyamide acid-based compound contains: a skeleton derived from a tetracarboxylic acid compound having a cyclobutane skeleton, by 20 mol% or less; a skeleton derived from a pyromellitic acid dianhydride, by 10 mol% or less; and a skeleton derived from a diamine compound having a primary amino group, a secondary amino group or a nitro group, by 10 mol% or less.SELECTED DRAWING: None

Description

  The present invention relates to a varnish for a photo-alignment film and a liquid crystal display device.

  The liquid crystal display device includes a first substrate on which pixel electrodes, thin film transistors (TFTs) and the like are formed in a matrix, and a second substrate on which a color filter and the like are disposed so as to be spaced apart from the first substrate. Liquid crystal is sealed between the first substrate and the second substrate. The liquid crystal is aligned by alignment films provided on the first substrate and the second substrate, respectively.

  A polyimide film is often used for the alignment film. As a method for aligning the polyimide film, recently, in addition to the rubbing process, a photo-alignment process that imparts alignment control ability to the polyimide film in a non-contact manner is employed (for example, see Patent Document 1). Compared with the rubbing process, the photo-alignment process does not cause problems such as generation of static electricity and unevenness due to unevenness of the substrate surface.

  The photo-alignment treatment imparts uniaxial anisotropy to the polyimide film by, for example, irradiating the polyimide film with polarized ultraviolet rays in the region of 254 nm to 365 nm and cutting the polyimide film molecules in a direction parallel to the polarization direction. The liquid crystal molecules are initially aligned by a polyimide film (alignment film) imparted with uniaxial anisotropy.

JP 2004-206091 A

  When a liquid crystal display device including a photo-aligned polyimide film (photo-alignment film) is driven for a long time, image sticking may occur in the liquid crystal display device as the drive time elapses. One of the image sticking of the liquid crystal display device is an afterimage (DC afterimage) generated by the accumulation of DC charges in the photo-alignment film. It is known that the occurrence of a DC afterimage in a liquid crystal display device can be suppressed or prevented by reducing the resistivity of the photoalignment film and suppressing the accumulation of DC charge in the photoalignment film.

  However, when a liquid crystal display device including a photo-alignment film having such a reduced resistivity is driven at a low frequency (for example, driven at 30 Hz or less), the luminance decreases due to a decrease in the retained charge of the photo-alignment film, and flickers. That is, there is a risk of flicker.

An object of the present invention is to provide a varnish for forming a photo-alignment film that does not cause or suppress a DC afterimage and flicker during low-frequency driving in a liquid crystal display device.
The other subject of this invention is providing a liquid crystal display device provided with the said photo-alignment film.

  According to an embodiment of the present invention, a polyamic acid or a polyamic acid ester having a higher polarity than the first polyamic acid-based compound and a first polyamic acid-based compound that is a polyamic acid or a polyamic acid ester in an organic solvent. And the second polyamic acid compound is present in a larger amount than the first polyamic acid compound.

  In the first polyamic acid compound, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the first polyamic acid compound is 100 mol%, the following formula (1 ):

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｒ^ａは、それぞれ、水素又はアルキル基である）で表されるシクロブタン骨格を有するテトラカルボン酸化合物由来の骨格のモル百分率は、５０モル％以上、及び前記第１ポリアミド酸系化合物中のジアミン化合物由来の骨格のモル百分率を１００モル％としたときに、当該第１ポリアミド酸系化合物中の下記式（２）：

(In Formula (1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively) The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula is 50 mol% or more, and the molar percentage of the skeleton derived from the diamine compound in the first polyamic acid compound is 100 mol%. And the following formula (2) in the first polyamic acid-based compound:

（式（２）中、Ｊは、Ａｒ^１、又はＡｒ^２−Ｋ−Ａｒ^３であり、Ａｒ^１、Ａｒ^２及びＡｒ^３は、それぞれ独立に、第一級アミノ基、第二級アミノ基又はニトロ基を含有する芳香族基であり、Ｋは、第一級アミノ基又は第二級アミノ基を含有する有機基である）で表されるジアミン化合物由来の骨格のモル百分率は、１０モル％以下である。

(In the formula (2), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or A nitro group-containing aromatic group, and K is an organic group containing a primary amino group or a secondary amino group). It is as follows.

  In the second polyamic acid compound, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the second polyamic acid compound is 100 mol%, the following formula (3 -1):

（式（３−１）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｒ^ａは、それぞれ、水素又はアルキル基である）で表されるシクロブタン骨格を有するテトラカルボン酸化合物由来の骨格のモル百分率は、２０モル％以下、及び当該第２ポリアミド酸系化合物中の下記式（３−２）：

(In Formula (3-1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively. The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula (2) is 20 mol% or less, and the following formula (3-2) in the second polyamic acid-based compound:

（式（３−２）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）である）で表されるピロメリット酸二無水物由来の骨格のモル百分率は、１０モル％以下、並びに前記第２ポリアミド酸系化合物中のジアミン化合物由来の骨格のモル百分率を１００モル％としたときに、当該第２ポリアミド酸系化合物中の下記式（４）：

(In formula (3-2), R ¹ and R ² are each independently derived from pyromellitic dianhydride represented by —COOH or COOR (where R is an alkyl group)). The molar percentage of the skeleton is 10 mol% or less, and when the molar percentage of the skeleton derived from the diamine compound in the second polyamic acid compound is 100 mol%, the following formula in the second polyamic acid compound (4):

（式（４）中、Ｊは、Ａｒ^１、又はＡｒ^２−Ｋ−Ａｒ^３であり、Ａｒ^１、Ａｒ^２及びＡｒ^３は、それぞれ独立に、第一級アミノ基、第二級アミノ基又はニトロ基を含有する芳香族基であり、Ｋは、第一級アミノ基又は第二級アミノ基を含有する有機基である）で表されるジアミン化合物由来の骨格のモル百分率は、１０モル％以下である光配向膜用ワニスが提供される。

(In the formula (4), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or A nitro group-containing aromatic group, and K is an organic group containing a primary amino group or a secondary amino group). The following varnish for photo-alignment films is provided.

  According to another embodiment of the present invention, a first substrate having an alignment film, a second substrate disposed facing the alignment film side of the first substrate, the first substrate, and the second substrate A liquid crystal display device is provided, wherein the alignment film includes the imidized product of the varnish for a photo alignment film described above.

1 is a schematic plan view of a liquid crystal display device according to an embodiment. It is a figure which expands and shows the partially broken schematic cross section along the ii-ii line of FIG. It is a schematic diagram which shows the structure of the photo-alignment film | membrane of the two-layer structure concerning embodiment.

  The present inventors set a common voltage (Vcom) that minimizes flicker for a simple liquid crystal cell having a low-resistivity photo-alignment film (initial value), and continuously illuminates backlight light under the Vcom. It was confirmed that flicker increased. At that time, when Vcom at which the flicker was minimized was measured, the value was different from the initial value (Vcom drift). This indicates that DC charges were accumulated in the liquid crystal cell.

  Furthermore, since the liquid crystal cell described above is a simple liquid crystal cell, the present inventors infer that the DC charge is not derived from driving but is caused by the photocharge generated in the photo-alignment film near the electrode. Has been found to depend mainly on the amount of specific amine components. Depending on the amount of the specific amine component, it is presumed that radicals and the like are generated when the polarized ultraviolet ray is irradiated to the polyimide film, which affects other alignment film structures or alignment film characteristics. In addition, it has been found that flicker during low-frequency driving can be prevented by the fact that the entire photo-alignment film exhibits a relatively high resistivity.

  Hereinafter, some embodiments will be described with reference to the drawings. In addition, although the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part as compared with the actual mode for clarity of explanation, they are merely examples, and The interpretation is not limited. In addition, in the present specification and each drawing, components that perform the same or similar functions as those described with respect to the preceding drawings are denoted by the same reference numerals, and repeated detailed description may be omitted as appropriate. .

<Liquid crystal display device>
First, a liquid crystal display device DSP according to an embodiment will be described with reference to FIGS. FIG. 1 is a schematic plan view of a liquid crystal display device DSP, and FIG. 2 is an enlarged view showing a partially broken schematic cross section along the line ii-ii in FIG.

In this embodiment, the direction parallel to the short side of the liquid crystal display device DSP is the first direction X, the direction parallel to the long side of the liquid crystal display device DSP is the second direction Y, and the first direction X and the second direction. A direction perpendicular to Y is a third direction Z. The first direction X and the second direction Y are orthogonal to each other in the present embodiment, but may intersect at an angle other than 90 degrees.
In the present embodiment, the positive direction in the third direction Z is defined as up or above, and the negative direction in the third direction Z is defined as down or down. Further, viewing the liquid crystal display device DSP from above is defined as a plan view. The liquid crystal display device DSP in plan view can be seen in the plan view (FIG. 1).

  As shown in FIG. 1, the liquid crystal display device DSP includes a display panel PNL, a flexible printed circuit board 1, an IC chip 2, and a circuit board 3. The display panel PNL is a liquid crystal display panel, and includes a first substrate SUB1, a second substrate SUB2, a liquid crystal layer LC described later, a seal SE, a light shielding layer LS, and spacers SP1 to SP4.

  The first substrate SUB1 and the second substrate SUB2 are disposed so as to face each other. The first substrate SUB1 includes a region facing the second substrate SUB2 and a mounting part MA extending in the second direction Y from the second substrate SUB2. In other words, the mounting part MA of the first substrate SUB1 extends outward from the edge of the second substrate SUB2.

  The flexible printed circuit board 1 is mounted on the mounting part MA of the first substrate SUB1. The IC chip 2 is electrically connected to the flexible printed circuit board 1. The IC chip 2 may be mounted on the mounting part MA. The IC chip 2 includes a display driver DD that outputs a signal necessary for image display in a display mode for displaying an image. In the illustrated example, the IC chip 2 includes a touch controller TC that controls a touch sensing mode for detecting approach or contact of an object to the display device DSP. In the figure, the IC chip 2 is indicated by a one-dot chain line, and the display driver DD and the touch controller TC are indicated by a dotted line. The circuit board 3 is electrically connected to the second half of the flexible printed circuit board 1 in the second direction Y, and transmits a drive signal through the flexible printed circuit board 1 to the first board SUB1.

The first substrate SUB1 and the second substrate SUB2 are bonded to each other at the peripheral edge of the first substrate SUB1 and the peripheral edge of the second substrate SUB2 except for the mounting portion MA by a seal SE formed in a frame shape. The frame-shaped seal SE defines a certain cell gap between the first substrate SUB1 and the second substrate SUB2. Liquid crystal is sealed inside the seal SE to form a liquid crystal layer LC described later.
Further, the frame-shaped seal SE defines the non-display portion NDA. The light shielding layer LS is provided at a position overlapping the seal SE in plan view. In FIG. 1, a region where the seal SE is disposed and a region where the light shielding layer LS are disposed are indicated by different oblique lines, and a region where the seal SE and the light shielding layer LS overlap is indicated by cross hatching. The light shielding layer LS is provided on the second substrate SUB2.

  The spacers SP1 to SP4 are respectively provided in a frame shape on the first substrate SUB1, the second substrate SUB2, and the non-display portion NDA. The spacer SP1 is located on the outermost periphery of the second substrate SUB2. The spacer SP2 is located closer to the display part DA than the spacer SP1. The spacers SP1 and SP2 overlap the seal SE. The spacers SP3 and SP4 are located closer to the display part DA than the seal SE. The spacers SP1 to SP4 define a certain cell gap between the first substrate SUB1 and the second substrate SUB2 together with the frame-shaped seal SE. The spacers SP1 to SP4 are provided on the second substrate SUB2, for example, but may be provided on the first substrate SUB1.

  The non-display portion NDA defines a display portion DA that displays an image inside. The display unit DA includes a plurality of pixels PX arranged in a matrix in the first direction X and the second direction Y.

The display panel PNL of the present embodiment has a transmissive display function for displaying an image by selectively transmitting light from the back side of the first substrate SUB1, and light from the front side of the second substrate SUB2. May be either a reflective type having a reflective display function for displaying an image by selectively reflecting the light, or a transflective type having a transmissive display function and a reflective display function.
The detailed configuration of the display panel PNL is omitted here, but the display panel PNL has a display mode that uses a horizontal electric field along the main surface of the substrate and a vertical electric field along the normal of the main surface of the substrate. Display mode to be used, display mode using a gradient electric field inclined in an oblique direction with respect to the main surface of the substrate, and any one corresponding to a display mode using an appropriate combination of the horizontal electric field, vertical electric field, and gradient electric field. You may have the structure of. Here, the substrate main surface is a surface parallel to the XY plane defined by the first direction X and the second direction Y.

  As shown in FIG. 2, the first substrate SUB1 includes the first insulating substrate 10, the insulating films 11 to 16, the signal lines S1 and S2, the metal wirings ML1 and ML2, the common electrode CE, and the pixel electrode PE. I have. Note that the example shown in FIG. 2 corresponds to an example in which an FFS (Fringe Field Switching) mode, which is one of display modes using a horizontal electric field, is applied.

  The first insulating substrate 10 is a light transmissive substrate such as a glass substrate or a flexible resin substrate. An optical element OD1 including a polarizing plate PL1 is bonded to the lower surface of the first insulating substrate 10. The optical element OD1 may include a retardation plate, a scattering layer, an antireflection layer, and the like as necessary. An illumination device IL is provided below the optical element OD1.

  The insulating film 11 is disposed on the first insulating substrate 10, the insulating film 12 is disposed on the insulating film 11, and the insulating film 13 is disposed on the insulating film 12. The insulating films 11 to 13 are inorganic insulating films formed of an insulating inorganic material such as silicon oxide, silicon nitride, or silicon oxynitride, and may have a single layer structure or a multilayer structure. May be.

  The signal lines S1 and S2 are disposed on the same insulating film 13. These signal lines are made of a metal material such as aluminum (Al), titanium (Ti), silver (Ag), molybdenum (Mo), tungsten (W), copper (Cu), chromium (Cr), or the above metal material. Each may be formed of a combined alloy or the like, and may have a single layer structure or a multilayer structure. In one example, each of the signal lines S1 and S2 is a stacked body in which a layer containing titanium (Ti), a layer containing aluminum (Al), and a layer containing titanium (Ti) are stacked in this order.

  The insulating film 14 is disposed on the insulating film 13 and the signal lines S1 and S2 so as to cover them. The insulating film 14 is an organic insulating film formed of an insulating organic material such as acrylic resin.

  The metal wirings ML1 and ML2 are disposed on the same insulating film 14. The metal wirings ML1 and ML2 are formed of the above metal material, an alloy combining the above metal materials, or the like, and may have a single layer structure or a multilayer structure. In one example, each of the metal wirings ML1 and ML2 includes a layered body in which a layer containing titanium (Ti), a layer containing aluminum (Al), and a layer containing titanium (Ti) are stacked in this order, or molybdenum (Mo ), A layer containing aluminum (Al), and a layer containing molybdenum (Mo) are stacked in this order.

  The insulating film 15 is disposed on the insulating film 14 and the metal wirings ML1 and ML2 so as to cover them. The insulating film 15 is an organic insulating film formed of an insulating organic material such as an acrylic resin, for example, like the insulating film 14. The insulating film 15 may be an inorganic insulating film.

  The common electrode CE is disposed on the insulating film 15. The common electrode CE is a transparent electrode formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

  The insulating film 16 is disposed on the common electrode CE. The insulating film 16 is an inorganic insulating film formed of an insulating inorganic material such as silicon oxide, silicon nitride, or silicon oxynitride similarly to the insulating films 11 to 13, and has a single layer structure. It may be a multilayer structure.

  The pixel electrode PE is disposed on the insulating film 16. The pixel electrode PE is a transparent electrode formed of a transparent conductive material such as ITO or IZO.

On the pixel electrode PE and the insulating film 16, a first alignment film AL1 is provided so as to cover them. The first alignment film AL1 preferably has a resistivity of 9.0 × 10 ¹⁴ Ω · cm or more. The detailed configuration of the first alignment film AL1 will be described later.

  The second substrate SUB2 includes a second insulating substrate 20, a color filter CF, a light shielding film BM, and an overcoat layer OC.

  Similar to the first insulating substrate 10, the second insulating substrate 20 is a light-transmitting substrate such as a glass substrate or a flexible resin substrate. An optical element OD2 including a polarizing plate PL2 is bonded to the second insulating substrate 20. The optical element OD2 may include a retardation plate, a scattering layer, an antireflection layer, and the like as necessary.

  The color filter CF is located on the side of the second insulating substrate 20 facing the first substrate SUB1. The color filter CF includes a green color filter segment CFG, which is adjacent to red and blue color filter segments CFR and CFB. The color filter CF is disposed at a position facing the pixel electrode PE, and a light shielding film BM for preventing color mixture between the color filter segments is disposed. The overcoat layer OC covers the color filter CF. The overcoat layer OC is formed of a transparent resin.

A second alignment film AL2 is provided on the side of the overcoat layer OC that faces the first substrate SUB1. The second alignment film AL2 preferably has a resistivity of 9.0 × 10 ¹⁴ Ω · cm or more. The detailed configuration of the second alignment film AL2 will be described later.

  The liquid crystal layer LC is located between the first substrate SUB1 and the second substrate SUB2, and is held between the first alignment film AL1 and the second alignment film AL2. The liquid crystal layer LC includes liquid crystal molecules LM. The liquid crystal layer LC is composed of a positive type (positive dielectric anisotropy) liquid crystal material or a negative type (negative dielectric anisotropy) liquid crystal material.

  In such a display panel PNL, in an off state where no electric field is formed between the pixel electrode PE and the common electrode CE, the liquid crystal molecules LM are predetermined between the first alignment film AL1 and the second alignment film AL2. The initial orientation is in the direction of. In such an off state, the light emitted from the illumination device IL toward the display panel PNL is absorbed by the optical element OD1 and the optical element OD2, and dark display is performed. On the other hand, in the ON state in which an electric field is formed between the pixel electrode PE and the common electrode CE, the liquid crystal molecules LM are aligned in a direction different from the initial alignment direction by the electric field, and the alignment direction is controlled by the electric field. . In such an on state, a part of the light from the illumination device IL is transmitted through the optical element OD1 and the optical element OD2 and is brightly displayed.

  The alignment films (first alignment film AL1 and second alignment film AL2) according to the embodiment are obtained by applying a photo-alignment film varnish on a substrate (first substrate SUB1, second substrate SUB2) and heating it to form a polyimide film. The orientation control ability is given by converting and irradiating polarized ultraviolet rays to the polyimide film. In some embodiments, the first alignment film AL1 and the second alignment film AL2 are imidized products (photo-alignment films) of the varnish for the photo-alignment film.

<Varnish for photo-alignment film>
The varnish for photo-alignment films according to the embodiment includes a first polyamic acid compound that is a polyamic acid or a polyamic acid ester in an organic solvent, and a polyamic acid or a polyamide having a higher polarity than the first polyamic acid compound. A second polyamic acid compound that is an acid ester, and the second polyamic acid compound is present in a larger amount than the first polyamic acid compound.
In some embodiments, the varnish for a photoalignment film has a weight ratio of the first polyamic acid-based compound to the second polyamic acid-based compound from 4: 6 to 2: 8, and from 4: 6 to 3: 7. It is preferable that
The polyamic acid can be synthesized by reacting a tetracarboxylic acid compound (tetracarboxylic dianhydride) and a diamine compound as described later. The polyamic acid ester can be synthesized by esterifying the polyamic acid.
Therefore, the first and second polyamic acid compounds each have a skeleton derived from a tetracarboxylic acid compound and a skeleton derived from a diamine compound.

<First polyamic acid compound>
In the first polyamic acid-based compound according to the embodiment, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the first polyamic acid-based compound is 100 mol%, the following formula in the first polyamic acid-based compound: (1):

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｒ^ａは、それぞれ、水素又はアルキル基である）で表されるシクロブタン骨格を有するテトラカルボン酸化合物由来の骨格のモル百分率は、５０モル％以上、及び第１ポリアミド酸系化合物中のジアミン化合物由来の骨格のモル百分率を１００モル％としたときに、当該第１ポリアミド酸系化合物中の下記式（２）：

(In Formula (1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively) The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula is 50 mol% or more, and the molar percentage of the skeleton derived from the diamine compound in the first polyamic acid compound is 100 mol%. The following formula (2) in the first polyamic acid-based compound:

（式（２）中、Ｊは、Ａｒ^１、又はＡｒ^２−Ｋ−Ａｒ^３であり、Ａｒ^１、Ａｒ^２及びＡｒ^３は、それぞれ独立に、第一級アミノ基、第二級アミノ基又はニトロ基を含有する芳香族基であり、Ｋは、第一級アミノ基又は第二級アミノ基を含有する有機基である）で表されるジアミン化合物由来の骨格のモル百分率は、１０モル％以下である。

(In the formula (2), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or A nitro group-containing aromatic group, and K is an organic group containing a primary amino group or a secondary amino group). It is as follows.

In the first polyamic acid-based compound according to the embodiment, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the first polyamic acid-based compound is 100 mol%, the above formula in the first polyamic acid-based compound The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by (1) is preferably 80 mol% or more.
When R ^a in the above formula (1) is an alkyl group, R ^a is, for example, an alkyl group having 1 to 6 carbon atoms. As the alkyl group, a methyl group is particularly preferable.

  In some embodiments, the skeleton derived from the tetracarboxylic acid compound in the first polyamic acid compound is a skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (1), and the following formula (1 -1):

（式（１−１）中、Ｒ^１及びＲ^２は、式（１）に関して定義した通りであり、Ｘ^１は、シクロブタン骨格以外の脂環式骨格、鎖式骨格、又は芳香族基である）で表されるテトラカルボン酸化合物由来の骨格を含み得る（５０モル％未満、好ましくは２０モル％未満）。
上記式（１−１）において、シクロブタン骨格以外の脂環式骨格は、例えばシクロペンタン骨格、シクロヘキサン骨格、ビシクロ［２，２，１］ヘプタン骨格、２−メチルビシクロ［２，２，１］ヘプタン骨格であり、鎖式骨格は、例えばブチル骨格であり、芳香族基は、例えばベンゼン環である。

(In formula (1-1), R ¹ and R ² are as defined for formula (1), and X ¹ is an alicyclic skeleton other than a cyclobutane skeleton, a chain skeleton, or an aromatic group. ) Derived from a tetracarboxylic acid compound (less than 50 mol%, preferably less than 20 mol%).
In the above formula (1-1), examples of the alicyclic skeleton other than the cyclobutane skeleton include a cyclopentane skeleton, a cyclohexane skeleton, a bicyclo [2,2,1] heptane skeleton, and a 2-methylbicyclo [2,2,1] heptane. The skeleton, the chain skeleton is, for example, a butyl skeleton, and the aromatic group is, for example, a benzene ring.

  In the first polyamic acid-based compound according to the embodiment, when the mole percentage of the skeleton derived from the diamine compound in the first polyamic acid-based compound is 100 mol%, the above formula (2 It is preferable that the mole percentage of the skeleton derived from the diamine compound represented by) is 5 mol% or less. The “10 mol% or less” and “5 mol% or less” include 0 mol%, and the molar percentage of the skeleton derived from the diamine compound represented by the above formula (2) in the first polyamic acid compound. Is more preferably 0 mol%.

  In some embodiments, the skeleton derived from the diamine compound in the first polyamic acid-based compound has the following formula (5):

（式（５）中、Ｌは、Ａｒ^４、又はＡｒ^５−Ｍ−Ａｒ^６であり、Ａｒ^４、Ａｒ^５及びＡｒ^６は、それぞれ独立に、第一級アミノ基、第二級アミノ基及びニトロ基を含有しない芳香族基であり、Ｍは、第一級アミノ基及び第二級アミノ基を含有しない有機基である）で表されるジアミン化合物由来の骨格を９０モル％以上含み得る（好ましくは１００モル％）。

(In Formula (5), L is Ar < ⁴ > or Ar < ⁵ > -M-Ar < ⁶ >, Ar < ⁴ >, Ar < ⁵ > and Ar < ⁶ > are respectively independently a primary amino group, a secondary amino group, and It is an aromatic group that does not contain a nitro group, and M can contain 90 mol% or more of a skeleton derived from a diamine compound represented by a primary amino group and an organic group that does not contain a secondary amino group. Preferably 100 mol%).

In some embodiments, Ar ⁴ , Ar ^5, and Ar ⁶ in Formula (5) are aromatic having a halogen atom, a hydroxyl group, a thiol group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms. It is a family group. Examples of the aromatic group represented by Ar ⁴ , Ar ⁵ and Ar ⁶ are a benzene ring or a group containing a benzene ring.

  In some embodiments, M in formula (5) is an organic group consisting of oxygen, nitrogen, sulfur, carbon and hydrogen, or a combination of two or more thereof.

  As described above, the first polyamic acid compound includes the skeleton derived from the tetracarboxylic acid compound represented by the above formula (1) or the above formulas (1) and (1-1), and the above formula (5). And a structural unit (repeating unit) represented by the following formula (6-1).

式（６−１）において、Ｒ^ａは、式（１）に関して定義した通りであり、Ｒ^１及びＲ^２は、式（１）に関して定義した通りであり、Ｌは、式（５）に関して定義した通りである。

In formula (6-1), R ^a is as defined for formula (1), R ¹ and R ² are as defined for formula (1), and L is defined for formula (5). That's right.

  In another embodiment, the first polyamic acid-based compound has a structural unit (repeating unit) represented by the following formula (6-2) in addition to the structural unit represented by the above formula (6-1).

式（６−２）において、Ｘ^１は、式（１−１）に関して定義した通りであり、Ｒ^１及びＲ^２は、式（１）に関して定義した通りであり、Ｌは、式（５）に関して定義した通りである。

In formula (6-2), X ¹ is as defined for formula (1-1), R ¹ and R ² are as defined for formula (1), and L is formula (5) As defined above.

<Production of first polyamic acid compound>
A 1st polyamic-acid type compound can be manufactured as a polyamic acid by making a diamine compound and a tetracarboxylic acid compound (tetracarboxylic dianhydride) react by a conventional method.
The polyamic acid ester can be produced by reacting, for example, N, N-dimethylformamide dialkyl acetal with polyamic acid. Alternatively, the polyamic acid ester can also be produced by the method described in JP 2000-273172 A.

  In some embodiments, the tetracarboxylic acid compound used for the synthesis of the first polyamic acid-based compound is represented by the following formula (7-1):

（式（７−１）中、Ｒ^ａは、式（１）に関して定義した通りである）で表されるシクロブタン骨格を有するテトラカルボン酸化合物である。
上記式（７−１）で表されるシクロブタン骨格を有するテトラカルボン酸化合物は、第１ポリアミド酸系化合物の合成に用いるテトラカルボン酸化合物の全モル％（１００モル％）のうち、５０モル％以上であり、８０モル％以上であることが好ましい。

(In formula (7-1), R ^a is as defined for formula (1)) and is a tetracarboxylic acid compound having a cyclobutane skeleton.
The tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (7-1) is 50 mol% of the total mol% (100 mol%) of the tetracarboxylic acid compound used for the synthesis of the first polyamic acid compound. It is above, and it is preferable that it is 80 mol% or more.

  Examples of the tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (7-1) include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3. , 4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,2,3,4-tetramethyl-1,2,3 , 4-cyclobutanetetracarboxylic dianhydride. The tetracarboxylic acid compound having a cyclobutane skeleton is 1,2,3,4-cyclobutanetetracarboxylic dianhydride or 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. It is preferable.

  In another embodiment, the tetracarboxylic acid compound used for the synthesis of the first polyamic acid compound is represented by the following formula (7-2):

（式（７−２）中、Ｘ^１は、式（１−１）に関して定義した通りである）で表されるテトラカルボン酸化合物であり得る。
上記式（７−２）で表されるテトラカルボン酸化合物は、第１ポリアミド酸系化合物の合成に用いるテトラカルボン酸化合物の全モル％（１００モル％）のうち、５０モル％未満であり、２０モル％未満であることが好ましい。

(In formula (7-2), X ¹ is as defined in relation to formula (1-1)).
The tetracarboxylic acid compound represented by the formula (7-2) is less than 50 mol% of the total mol% (100 mol%) of the tetracarboxylic acid compound used for the synthesis of the first polyamic acid compound, It is preferable that it is less than 20 mol%.

An example of a tetracarboxylic acid compound represented by the above formula (7-2) in which X ¹ has an alicyclic skeleton other than the cyclobutane skeleton is 1,2,3,4-cyclopentanetetracarboxylic dianhydride 1,2,3,5-cyclohexanetetracarboxylic dianhydride, bicyclo [2,2,1] heptane-2,3,5,6-tetracarboxylic acid 2; 3,5; 6-dianhydride, And 3,5,6-tricarboxynorbornane-2-acetic acid 2,3; 5,6-dianhydride, 3- (carboxymethyl) -1,2,4-cyclopentanetricarboxylic acid 1,4: 2,3 Contains dianhydrides.

The tetracarboxylic acid compound in which X ¹ represented by the above formula (7-2) has a chain skeleton is, for example, meso-butane-1,2,3,4-tetracarboxylic dianhydride.

The tetracarboxylic acid compound in which X ¹ represented by the above formula (7-2) has an aromatic group is, for example, pyromellitic dianhydride.

  The diamine compound used for the synthesis of the first polyamic acid compound is represented by the following formula (8):

（式（８）中、Ｊは、式（２）に関して定義した通りである）で表されるジアミン化合物であり得る。しかしながら、上記式（８）で表されるジアミン化合物は、第１ポリアミド酸系化合物の合成に用いるジアミン化合物の全モル％（１００モル％）のうち、１０モル％以下であり、５モル％以下であることが好ましい。なお、上記「１０モル％以下」及び「５モル％以下」は、０モル％も含み、上記式（８）で表されるジアミン化合物は、０モル％であることがさらに好ましい。

(In formula (8), J may be as defined for formula (2)). However, the diamine compound represented by the above formula (8) is 10 mol% or less and 5 mol% or less of the total mol% (100 mol%) of the diamine compound used for the synthesis of the first polyamic acid compound. It is preferable that The “10 mol% or less” and “5 mol% or less” include 0 mol%, and the diamine compound represented by the formula (8) is more preferably 0 mol%.

  In some embodiments, the diamine compound used for the synthesis of the first polyamic acid-based compound is represented by the following formula (9):

（式（９）中、Ｌは、式（５）に関して定義した通りである）で表されるジアミン化合物であり得る。
上記式（９）で表されるジアミン化合物は、第１ポリアミド酸系化合物の合成に用いるジアミン化合物の全モル％（１００モル％）のうち、９０モル％以上であり、１００モル％であることが好ましい。

(In formula (9), L may be as defined for formula (5)).
The diamine compound represented by the formula (9) is 90 mol% or more and 100 mol% of the total mol% (100 mol%) of the diamine compound used for the synthesis of the first polyamic acid compound. Is preferred.

  Examples of the diamine compound represented by the above formula (9) are 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, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5- Dichlorobenzene, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-2,2′-dimethylbibenzyl, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3 , 4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 2,2′-diaminostilbene, 4, 4'-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4 , 4′-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5- Bis (4-aminophenoxy) benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4 -Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) pheny ] Propane, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4- Aminophenyl) hexafluoropropane, 4,4′-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bi (4-aminophenyl) tetramethyldisiloxane, benzidine, 2,2′-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4 -Bis (4-aminophenyl) butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, , 8-bis (4-aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1, 7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, Di (4-aminophenyl) propane-1,3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-amino) Phenyl) hexane-1,6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1 , 9-dioate, di (4-aminophenyl) decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propa 1,4-bis [4- (4-aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) ) Phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- ( 4-aminophenoxy) phenoxy] nonane and 1,10-bis [4- (4-aminophenoxy) phenoxy] decane. Furthermore, the example of the diamine shown by Formula (9) is shown below (in the following examples, n is an integer of 1-10).

<Second polyamic acid compound>
In the second polyamic acid compound according to the embodiment, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the second polyamic acid compound is 100 mol%, the following formula in the second polyamic acid compound (3-1):

（式（３−１）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｒ^ａは、それぞれ、水素又はアルキル基である）で表されるシクロブタン骨格を有するテトラカルボン酸化合物由来の骨格のモル百分率は、２０モル％以下、及び当該第２ポリアミド酸系化合物中の下記式（３−２）：

(In Formula (3-1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively. The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula (2) is 20 mol% or less, and the following formula (3-2) in the second polyamic acid-based compound:

（式（３−２）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）である）で表されるピロメリット酸二無水物由来の骨格のモル百分率は、１０モル％以下、並びに第２ポリアミド酸系化合物中のジアミン化合物由来の骨格のモル百分率を１００モル％としたときに、当該第２ポリアミド酸系化合物中の下記式（４）：

(In formula (3-2), R ¹ and R ² are each independently derived from pyromellitic dianhydride represented by —COOH or COOR (where R is an alkyl group)). The molar percentage of the skeleton is 10 mol% or less, and when the molar percentage of the skeleton derived from the diamine compound in the second polyamic acid compound is 100 mol%, the following formula ( 4):

（式（４）中、Ｊは、Ａｒ^１、又はＡｒ^２−Ｋ−Ａｒ^３であり、Ａｒ^１、Ａｒ^２及びＡｒ^３は、それぞれ独立に、第一級アミノ基、第二級アミノ基又はニトロ基を含有する芳香族基であり、Ｋは、第一級アミノ基又は第二級アミノ基を含有する有機基である）で表されるジアミン化合物由来の骨格のモル百分率は、１０モル％以下である。

(In the formula (4), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or A nitro group-containing aromatic group, and K is an organic group containing a primary amino group or a secondary amino group). It is as follows.

In the second polyamic acid compound according to the embodiment, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the second polyamic acid compound is 100 mol%, the above formula in the second polyamic acid compound is used. The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by (3-1) is preferably 10 mol% or less. The above “20 mol% or less” and “10 mol% or less” include 0 mol%, and the tetracarboxylic acid having a cyclobutane skeleton represented by the above formula (3-1) in the second polyamic acid compound. The mole percentage of the skeleton derived from the acid compound is more preferably 0 mol%.
When R ^a in the above formula (3-1) is an alkyl group, R ^a is, for example, an alkyl group having 1 to 6 carbon atoms. As the alkyl group, a methyl group is particularly preferable.

  In the second polyamic acid-based compound according to the embodiment, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the second polyamic acid-based compound is 100 mol%, The molar percentage of the skeleton derived from pyromellitic dianhydride represented by the above formula (3-2) is preferably 5 mol% or less. The above “10 mol% or less” and “5 mol% or less” include 0 mol%, and pyromellitic dianhydride represented by the above formula (3-2) in the second polyamic acid compound. The mole percentage of the skeleton derived from is more preferably 0 mol%.

  In some embodiments, the skeleton derived from a tetracarboxylic acid compound in the second polyamic acid compound is a skeleton derived from a tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (3-1) and the above formula (3). -2) In addition to the skeleton derived from pyromellitic dianhydride represented by the following formula (10):

（式（１０）中、Ｒ^１及びＲ^２は、それぞれ独立に、−ＣＯＯＨ又はＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｘ^２は、シクロブタン骨格以外の脂環式骨格、又は鎖式骨格である）で表されるテトラカルボン酸化合物由来の骨格を含み得る（７０モル％以上、好ましくは８５モル％以上、さらに好ましくは１００モル％）。
上記式（１０）において、シクロブタン骨格以外の脂環式骨格は、例えばシクロペンタン骨格、シクロヘキサン骨格、ビシクロ［２，２，１］ヘプタン骨格、２−メチルビシクロ［２，２，１］ヘプタン骨格であり、鎖式骨格は、例えばブチル骨格である。

(In Formula (10), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and X ² is an alicyclic skeleton other than a cyclobutane skeleton, Or a skeleton derived from a tetracarboxylic acid compound represented by a chain skeleton) (70 mol% or more, preferably 85 mol% or more, more preferably 100 mol%).
In the above formula (10), the alicyclic skeleton other than the cyclobutane skeleton is, for example, a cyclopentane skeleton, a cyclohexane skeleton, a bicyclo [2,2,1] heptane skeleton, or a 2-methylbicyclo [2,2,1] heptane skeleton. The chain skeleton is, for example, a butyl skeleton.

  In the second polyamic acid-based compound according to the embodiment, when the molar percentage of the skeleton derived from the diamine compound in the second polyamic acid-based compound is 100 mol%, the above formula (4) It is preferable that the mole percentage of the skeleton derived from the diamine compound represented by) is 5 mol% or less. The “10 mol% or less” and “5 mol% or less” include 0 mol%, and the molar percentage of the skeleton derived from the diamine compound represented by the above formula (4) in the second polyamic acid compound. Is more preferably 0 mol%.

  In some embodiments, the skeleton derived from the diamine compound in the second polyamic acid-based compound has the following formula (11-1):

（式（１１−１）中、Ｌは、Ａｒ^４、又はＡｒ^５−Ｍ−Ａｒ^６であり、Ａｒ^４、Ａｒ^５及びＡｒ^６は、それぞれ独立に、第一級アミノ基、第二級アミノ基及びニトロ基を含有しない芳香族基であり、Ｍは、第一級アミノ基及び第二級アミノ基を含有しない有機基である）で表されるジアミン化合物由来の骨格を９０モル％以上含み得る（好ましくは１００モル％）。

(In formula (11-1), L is Ar ⁴ or Ar ⁵ -M-Ar ⁶ , and Ar ⁴ , Ar ⁵ and Ar ⁶ are each independently a primary amino group or a secondary amino group. A diamine compound-derived skeleton represented by the following formula: M is an aromatic group containing no nitro group or nitro group, and M is an organic group containing no primary amino group or secondary amino group) To obtain (preferably 100 mol%).

In some embodiments, Ar ⁴ , Ar ⁵ and Ar ⁶ in formula (11-1) each represent a halogen atom, a hydroxyl group, a thiol group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms. It is an aromatic group. Examples of the aromatic group represented by Ar ⁴ , Ar ⁵ and Ar ⁶ are a benzene ring or a group containing a benzene ring.

  In some embodiments, M in formula (11-1) is an organic group consisting of oxygen, nitrogen, sulfur, carbon and hydrogen, or a combination of two or more thereof.

  In another embodiment, the skeleton derived from the diamine compound in the second polyamic acid compound has the following formula (11-2):

（式（１１−２）中、Ｌ^１は、酸素及び／又はフッ素を含有する有機基である）で表されるジアミン化合物由来の骨格を含み得る。

(In Formula (11-2), L ¹ is an organic group containing oxygen and / or fluorine) and may contain a skeleton derived from a diamine compound.

  In the second polyamic acid-based compound according to the embodiment, when the molar percentage of the skeleton derived from the diamine compound in the second polyamic acid-based compound is 100 mol%, the above formula (11 The sum of the mole percentages of the skeleton derived from the diamine compound represented by -1) and / or (11-2) is preferably 90 mol% or more, and more preferably 100 mol%.

  As described above, the second polyamic acid-based compound is represented by the skeleton derived from the tetracarboxylic acid compound represented by the above formula (10) and the above formula (11-1) and / or (11-2). Since it may contain a skeleton derived from a diamine compound, it has a structural unit (repeating unit) represented by the following formula (12-1).

式（１２−１）において、Ｘ^２は、式（１０）に関して定義した通りであり、Ｒ^１及びＲ^２は、式（１０）に関して定義した通りであり、Ｌは、式（１１−１）に関して定義した通りである。

In formula (12-1), X ² is as defined for formula (10), R ¹ and R ² are as defined for formula (10), and L is formula (11-1) As defined above.

  In another embodiment, the second polyamic acid compound has a structural unit (repeating unit) represented by the following formula (12-2) in addition to the structural unit represented by the above formula (12-1).

式（１２−２）において、Ｘ^２は、式（１０）に関して定義した通りであり、Ｒ^１及びＲ^２は、式（１０）に関して定義した通りであり、Ｌ^１は、式（１１−２）に関して定義した通りである。

In Formula (12-2), X ² is as defined for Formula (10), R ¹ and R ² are as defined for Formula (10), and L ¹ is Formula (11-2). ) As defined above.

The second polyamic acid-based compound has a higher polarity than the first polyamic acid-based compound. In some embodiments, the second polyamic acid-based compound has a structural unit (repeating unit) represented by the above formula (11-2) in addition to the structural unit represented by the above formula (11-1). It has higher polarity than the first polyamic acid-based compound, that is, has a larger surface energy.
When the polyamic acid ester and the polyamic acid coexist, the polyamic acid has a larger surface energy than the polyamic acid ester. That is, when the first polyamic acid compound is a polyamic acid ester and the second polyamic acid compound is a polyamic acid, the second polyamic acid compound has a larger surface energy than the first polyamic acid compound.

<Production of Second Polyamic Acid Compound>
A 2nd polyamic-acid type compound can be manufactured as a polyamic acid by making a diamine compound and a tetracarboxylic acid compound (tetracarboxylic dianhydride) react by a conventional method.
The polyamic acid ester can be produced according to the production method described for the first polyamic acid-based compound.

The tetracarboxylic acid compound used for the synthesis of the second polyamic acid compound may be a tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (7-1) and pyromellitic dianhydride.
However, the tetracarboxylic acid compound having a cyclobutane skeleton represented by the above formula (7-1) is 20% of the total mol% (100 mol%) of the tetracarboxylic acid compound used for the synthesis of the second polyamic acid compound. It is preferably at most 10 mol%, more preferably at most 0 mol%.
In addition, pyromellitic dianhydride is 10 mol% or less and 5 mol% or less of the total mol% (100 mol%) of the tetracarboxylic acid compound used for the synthesis of the second polyamic acid compound. Is preferable, and it is further more preferable that it is 0 mol%.

  In some embodiments, the tetracarboxylic acid compound used in the synthesis of the second polyamic acid-based compound is represented by the following formula (13):

（式（１３）中、Ｘ^２は、式（１０）に関して定義した通りである）で表されるテトラカルボン酸化合物であり得る。
上記式（１３）で表されるテトラカルボン酸化合物は、第２ポリアミド酸系化合物の合成に用いるテトラカルボン酸化合物の全モル％（１００モル％）のうち、９０モル％以上であり、１００モル％であることが好ましい。

(In formula (13), X ² is as defined for formula (10)).
The tetracarboxylic acid compound represented by the above formula (13) is 90 mol% or more and 100 mol of the total mol% (100 mol%) of the tetracarboxylic acid compound used for the synthesis of the second polyamic acid compound. % Is preferred.

As the tetracarboxylic dianhydride represented by the above formula (13), a tetracarboxylic dianhydride having an alicyclic skeleton other than a cyclobutane skeleton or a chain skeleton can be used.
The tetracarboxylic acid compound having an alicyclic skeleton other than the cyclobutane skeleton or the chain skeleton used for the synthesis of the second polyamic acid-based compound includes an alicyclic other than the cyclobutane skeleton used for the synthesis of the first polyamic acid-based compound. A tetracarboxylic acid compound having a formula skeleton or a chain skeleton can be used.

  The diamine compound used for the synthesis of the second polyamic acid-based compound may be a diamine compound represented by the above formula (8). However, the diamine compound represented by the above formula (8) is 10 mol% or less and 5 mol% or less of the total mol% (100 mol%) of the diamine compound used for the synthesis of the second polyamic acid compound. It is preferable that The “10 mol% or less” and “5 mol% or less” include 0 mol%, and the diamine compound represented by the formula (8) is more preferably 0 mol%.

  In some embodiments, the diamine compound used for the synthesis of the second polyamic acid compound is a diamine compound represented by the above formula (9) and the following formula (14):

（式（１４）中、Ｌ^１は、式（１１−２）に関して定義した通りである）で表されるジアミン化合物であり得る。
上記式（９）及び上記式（１４）で表されるジアミン化合物は、第１ポリアミド酸系化合物の合成に用いるジアミン化合物の全モル％（１００モル％）のうち、合計して９０モル％以上であり、合計して１００モル％であることが好ましい。

(In formula (14), L ¹ is as defined in relation to formula (11-2)).
The diamine compound represented by the above formula (9) and the above formula (14) is 90 mol% or more in total in the total mol% (100 mol%) of the diamine compound used for the synthesis of the first polyamic acid compound. It is preferable that it is 100 mol% in total.

As the diamine compound represented by the above formula (9) used for the synthesis of the second polyamic acid compound, the diamine compound represented by the above formula (9) used for the synthesis of the first polyamic acid compound is used. Can do.
As the diamine compound represented by the above formula (14) used for the synthesis of the second polyamic acid compound, the diamine compound having an organic group containing oxygen in the diamine compound represented by the above formula (9), or the above The diamine compound which introduce | transduced the organic group (fluoro group etc.) containing a fluorine into the aromatic group in the diamine compound represented by Formula (9) can be used.

<Organic solvent>
As an organic solvent for dissolving or dispersing the first and second polyamic acid compounds, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N -Ethyl pyrrolidone, N-vinyl pyrrolidone, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl Isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, and 4-hydroxy-4-methyl-2-pentanone, and butyl cellosolve can be used.

<Alignment film>
In the varnish for photo-alignment film according to the embodiment, since the second polyamic acid-based compound has a higher polarity than the first polyamic acid-based compound, that is, a larger surface energy, the first polyamic acid-based compound and the second polyamic acid-based compound The compound phase separates.
Referring to FIG. 2, when the photo-alignment film varnish containing the first and second polyamic acid-based compounds is applied on the pixel electrode PE and the insulating film 16 of the first substrate SUB1, the second polyamic acid-based varnish is applied. Since the compound has higher affinity between ITO or IZO for forming the pixel electrode PE and inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride for forming the insulating film 16, the second polyamide is used. The acid compound becomes the lower layer, and the first polyamic acid compound forms the upper layer and comes into contact with the liquid crystal layer LC.

  Also, when the photo-alignment film varnish is applied on the overcoat layer OC of the second substrate SUB2, the second polyamic acid compound has higher affinity with the overcoat layer OC using an organic resin. The second polyamic acid-based compound forms a lower layer and comes into contact with the overcoat layer OC, and the first polyamic acid-based compound forms an upper layer and comes into contact with the liquid crystal layer LC.

  The varnish for the photo-alignment film, which is applied to the coating object and separated into two phases, is imidized by heating at a temperature of about 200 ° C., and the bilayer film after imidization is subjected to photo-alignment treatment, that is, the alignment film, that is, photo-alignment Providing a membrane. The photo-alignment treatment can be performed by irradiating the imidized film with polarized ultraviolet rays having a wavelength of 254 nm to 365 nm. The first substrate SUB1 and the second substrate SUB2 including the imidized film subjected to the photo-alignment treatment may be further heated at a temperature of about 200 ° C.

  FIG. 3 is a schematic diagram illustrating a photo-alignment film (first alignment film AL1) having a two-layer structure according to the embodiment. The first alignment film AL1 is formed on the insulating film 16, and is formed of an upper layer AL1-1 and a lower layer AL1-2. Here, since the boundary between the upper layer AL1-1 and the lower layer AL1-2 of the first alignment film AL1 is not clear, those boundaries are indicated by dotted lines in FIG.

As described above, in the varnish for photo-alignment film according to the embodiment, since the second polyamic acid-based compound is present in a larger amount than the first polyamic acid-based compound, the proportion of the lower layer in the two-layered alignment film The lower layer becomes thicker than the upper layer.
In the photo-alignment film having the two-layer structure thus formed, the imidized product of the first polyamic acid compound having a low polarity forms the upper layer (liquid crystal side), and the imidized product of the second polyamic acid compound having a high polarity. However, it is formed in the lower layer (insulating substrate side).

  In some embodiments, the imidized product (polyimide) of the first polyamic acid compound forming the upper layer has a structural unit (repeating unit) represented by the following formula (15-1).

式（１５−１）において、Ｒ^ａは、式（１）に関して定義した通りであり、Ｌは、式（５）に関して定義した通りである。

In formula (15-1), R ^a is as defined for formula (1), and L is as defined for formula (5).

  In another embodiment, the imidized product of the first polyamic acid-based compound has a structural unit (repeating unit) represented by the following formula (15-2) in addition to the structural unit represented by the above formula (15-1). .

式（１５−２）において、Ｘ^１は、式（１−１）に関して定義した通りであり、Ｌは、式（５）に関して定義した通りである。

In formula (15-2), X ¹ is as defined for formula (1-1), and L is as defined for formula (5).

Since such an imidized product of the first polyamic acid compound is obtained by heating the first polyamic acid compound (condensation reaction), it has a skeleton derived from a tetracarboxylic acid compound and a skeleton derived from a diamine compound.
Therefore, in the imidized product of the first polyamic acid-based compound, when the mole percentage of the skeleton derived from the tetracarboxylic acid compound in the imidized product is 100 mol%, the formula (7-1) in the imidized product is represented by the above formula (7-1). The mole percentage of the skeleton derived from the tetracarboxylic acid compound is 50 mol% or more, and when the mole percentage of the skeleton derived from the diamine compound in the imidized product is 100 mol%, the above formula ( The mole percentage of the skeleton derived from the diamine compound represented by 8) is 10 mol% or less.

  In some embodiments, the imidized product (polyimide) of the second polyamic acid compound forming the lower layer has a structural unit (repeating unit) represented by the following formula (16-1).

式（１６−１）において、Ｘ^２は、式（１０）に関して定義した通りであり、Ｌは、式（１１−１）に関して定義した通りである。

In Formula (16-1), X ² is as defined for Formula (10), and L is as defined for Formula (11-1).

  In another embodiment, the imidized product of the second polyamic acid compound has a structural unit (repeating unit) represented by the following formula (16-2) in addition to the structural unit represented by the above formula (16-1). .

式（１６−２）において、Ｘ^２は、式（１０）に関して定義した通りであり、Ｌ^１は、式（１１−２）に関して定義した通りである。

In Formula (16-2), X ² is as defined for Formula (10), and L ¹ is as defined for Formula (11-2).

Since such an imidized product of the second polyamic acid compound is obtained by heating the second polyamic acid compound (condensation reaction), it has a skeleton derived from a tetracarboxylic acid compound and a skeleton derived from a diamine compound.
Therefore, in the imidized product of the second polyamic acid compound, when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the imidized product is 100 mol%, the formula (7-1) in the imidized product represents The mole percentage of the skeleton derived from the tetracarboxylic acid compound is 20 mol% or less, and the mole percentage of the skeleton derived from pyromellitic dianhydride in the imidized product is 10 mol% or less, and in the imidized product. When the mole percentage of the skeleton derived from the diamine compound is 100 mol%, the mole percentage of the skeleton derived from the diamine compound represented by the formula (8) in the imidized product is 10 mol% or less.

The imidized product of the first polyamic acid compound forming the upper layer is represented by the above formula (8) in the imidized product when the mole percentage of the skeleton derived from the diamine compound in the imidized product is 100 mol%. The mole percentage of the skeleton derived from the diamine compound is 10 mol% or less. Therefore, the polyimide film which is the imidized product suppresses generation of radicals and the like that can be generated when irradiated with polarized ultraviolet rays.
Similarly, the imidized product of the first polyamic acid compound forming the lower layer is represented by the above formula (8) in the imidized product when the mole percentage of the skeleton derived from the diamine compound in the imidized product is 100 mol%. The mole percentage of the skeleton derived from the represented diamine compound is 10 mol% or less. Therefore, the polyimide film which is the imidized product suppresses generation of radicals and the like that can be generated when irradiated with polarized ultraviolet rays.
Therefore, the photo-alignment film containing the imidized products of the first and second polyamic acid compounds can suppress the accumulation of DC charges and can suppress or prevent the DC afterimage.

Further, the imidized product of the first polyamic acid compound forming the upper layer has the above formula (7--) in the imidized product when the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the imidized product is 100 mol%. The molar percentage of the skeleton derived from the tetracarboxylic acid compound represented by 1) is 50 mol% or more. Therefore, the polyimide film which is the imidized product is easily imparted with an alignment control ability by the decomposition of the cyclobutane skeleton by the photoalignment treatment.
Therefore, the photo-alignment film containing the imidized product of the first polyamic acid compound is easily imparted with the alignment control ability by the photo-alignment treatment.

Further, the imidized product of the second polyamic acid compound forming the lower layer is composed of pyromellitic dianhydride in the imidized product when the mole percentage of the skeleton derived from the tetracarboxylic acid compound in the imidized product is 100 mol%. The mole percentage of the skeleton derived from the product is 10 mol% or less. Therefore, the polyimide film which is the imidized product exhibits a relatively high resistivity.
Therefore, the photo-alignment film containing such an imidized product of the second polyamic acid compound exhibits a relatively high resistivity, and can suppress or prevent flicker during low-frequency driving (for example, driving at 30 Hz or less).

Furthermore, the imidized product of the second polyamic acid compound forming the lower layer has the above formula (7-) in the imidized product when the mole percentage of the skeleton derived from the tetracarboxylic acid compound in the imidized product is 100 mol%. The mole percentage of the skeleton derived from the tetracarboxylic acid compound represented by 1) is 20 mol% or less. Therefore, the polyimide film which is the imidized product suppresses generation of radicals and the like that can be generated when irradiated with polarized ultraviolet rays.
Therefore, the photo-alignment film containing such an imidized product of the second polyamic acid compound can suppress the accumulation of DC charges and can suppress or prevent the DC afterimage.

  Further, such a photo-alignment film has a two-layer structure because the imidized product of the second polyamic acid compound forming the lower layer is present in a larger amount than the imidized product of the first polyamic acid compound forming the upper layer. Since the proportion of the first polyamic acid-based compound that is easily decomposed by the photo-alignment treatment in the photo-alignment film is reduced, generation of radicals that can be generated when irradiated with polarized ultraviolet rays is suppressed, and DC afterimage is suppressed or Can be prevented.

  In the above embodiment, the first alignment film AL1 and the second alignment film AL2 are formed from the varnish for optical alignment films of the present invention, but at least one of the first alignment film AL1 and the second alignment film AL2 is the main alignment film AL1. It should just be formed from the varnish for photo-alignment films of the invention.

EXAMPLES Hereinafter, although an Example demonstrates this invention, the synthesis example of a polyamic-acid type compound is described first.
Synthesis example of polyamic acid compounds
Synthesis example 1
N-methyl-2-pyrrolidone (NMP) solution of 100 mole parts of p-phenylenediamine (PDA) as a diamine compound and 1,3-dimethyl-1,2,3,4-cyclobutanetetra as a tetracarboxylic acid compound Carboxylic dianhydride (CBDA) 100 mol parts NMP solution and butyl cellosolve as organic solvent are mixed and all monomers are reacted at room temperature for 8 hours to produce polyamic acid, solid content concentration 15 mass % Of the desired polyamic acid solution was obtained.

Synthesis example 2
NMP solution of 100 mol parts of 4,4′-diaminodiphenyl ether (DPE) as a diamine compound and meso-butane-1,2,3,4-tetracarboxylic dianhydride (BDA) 100 as a tetracarboxylic acid compound A molar part NMP solution and butyl cellosolve as an organic solvent are mixed and all monomers are reacted at room temperature for 8 hours to produce polyamic acid, thereby obtaining a desired polyamic acid solution having a solid concentration of 15% by mass. It was.

Synthesis example 3
In Synthesis Example 2, instead of 100 mol parts of BDA as a tetracarboxylic acid compound, 80 mol parts of BDA and 20 mol parts of CBDA were used, and the solid content concentration was 15% by mass according to the production method described for Synthesis Example 2. The desired polyamic acid solution was obtained.

Synthesis example 4
In Synthesis Example 2, instead of 100 mol parts of BDA as a tetracarboxylic acid compound, a solid content concentration of 15% by mass was used in accordance with the production method described for Synthesis Example 2 except that 70 mol parts of BDA and 30 mol parts of CBDA were used. The desired polyamic acid solution was obtained.

Synthesis example 5
In Synthesis Example 2, instead of 100 mol parts of BDA as a tetracarboxylic acid compound, a solid content concentration of 15% by mass was obtained according to the production method described for Synthesis Example 2 except that 50 mol parts of BDA and 50 mol parts of CBDA were used. The desired polyamic acid solution was obtained.

Synthesis Example 6
NMP solution of 90 mol parts of DPE as diamine compound and 10 mol parts of 4,4′-diaminodiphenylamine (APA), NMP solution of 80 mol parts of BDA and 20 mol parts of CBDA as tetracarboxylic acid compound, and butyl cellosolve as organic solvent And all the monomers were reacted at room temperature for 8 hours to produce a polyamic acid to obtain a desired polyamic acid solution having a solid concentration of 15% by mass.

Synthesis example 7
In Synthesis Example 6, in place of 90 mol parts of DPE as a diamine compound and 10 mol parts of APA, 80 mol parts of DPE and 20 mol parts of APA were used, and the solid content concentration was 15 mass according to the production method described for Synthesis Example 6. % Of the desired polyamic acid solution was obtained.

Synthesis Example 8
In Synthesis Example 6, a solid content concentration of 15 mass according to the production method described for Synthesis Example 6 except that DPE 50 mol parts and APA 50 mol parts were used instead of DPE 90 mol parts and APA 10 mol parts as the diamine compound. % Of the desired polyamic acid solution was obtained.

Synthesis Example 9
In Synthesis Example 6, in accordance with the production method described for Synthesis Example 6, except that 100 mol parts of 4,4′-diaminodiphenylmethane (DPM) was used instead of 90 mol parts of DPE and 10 mol parts of APA as the diamine compound. A desired polyamic acid solution having a solid content concentration of 15% by mass was obtained.

Synthesis Example 10
In Synthesis Example 2, in place of 100 parts by mole of BDA as the tetracarboxylic acid compound, 90 parts by mole of BDA and 10 parts by mole of pyromellitic dianhydride (PMDA) were used. Thus, a desired polyamic acid solution having a solid concentration of 15% by mass was obtained.

Synthesis Example 11
In Synthesis Example 2, instead of 100 mol parts of BDA as a tetracarboxylic acid compound, 80 mol parts of BDA and 20 mol parts of PMDA were used, and the solid content concentration was 15% by mass according to the production method described for Synthesis Example 2. The desired polyamic acid solution was obtained.
The tetracarboxylic acid compounds and diamine compounds used in the synthesis of the polyamic acid compounds synthesized in Synthesis Examples 1 to 11 described above are shown in Table 1 below.

Examples 1 to 11
The upper layer component and the lower layer component shown in Table 2 below were mixed at a weight ratio of 4: 6 or 6: 4 to prepare coating solutions (varnishes for photo-alignment films) of Examples 1 to 11.
In the liquid crystal display device having the structure shown in FIG. 2, the coating liquid of Example 1 has a film thickness of 100 nm in the region where the first alignment film AL1 of the first substrate SUB1 and the second alignment film AL2 of the second substrate SUB2 are to be applied. Then, imidization was performed by heating at 230 ° C. for 10 minutes. The imidation ratio was 80% in all cases.

Each imidized film was subjected to photo-alignment treatment by irradiating polarized ultraviolet rays in the region of 254 nm to 365 nm in a direction of 80 ° with respect to the electrode angle. A short arc light source (UXM-5000BY, manufactured by Ushio Electric) was used for the photo-alignment treatment. The irradiation amount of polarized ultraviolet rays in the photo-alignment treatment was about 1.5 J / cm ² . The amount of irradiation is a value measured by an integrating illuminometer (manufactured by USHIO INC., UVD-S254 sensor).

  The imidized film after the photo-alignment treatment was heated at 230 ° C. for 30 minutes to form a photo-alignment film. The first substrate SUB1 and the second substrate SUB2 are used to form the photo-alignment film thus formed, and a seal is provided on the periphery of the photo-alignment film formed on one substrate so that the liquid crystal material is dropped and sealed, and the other substrate A liquid crystal cell was produced by pasting so as to face the photo-alignment film. The gap between the first substrate SUB1 and the second substrate SUB2 was 3 μm. As the liquid crystal, a negative liquid crystal material (Δn = 0.11) was used.

A polarizing plate was bonded to both surfaces of the produced liquid crystal cell so as to have a crossed Nicol, and the liquid crystal display device of Example 1 was produced by a conventional method. The lighting device used was a YAG (yttrium, aluminum, garnet phosphor) -LED light source of 10,000 cm / cm ² . The drive voltage was set to a voltage (2.2 V) that acquired voltage-luminance characteristics and was 22% of the maximum luminance. The liquid crystal display devices of Examples 2 to 11 were manufactured according to the manufacturing method of the liquid crystal display device of Example 1.

<Evaluation 1: Measurement of Vcom drift after 2 hours>
A luminance measuring device (manufactured by Topcom Techno House Co., Ltd., BM-5AS) was installed at a location 50 cm away from the liquid crystal display device of Example 1. With the lighting device turned on, a continuous output (analog output) of luminance was confirmed using an oscilloscope (manufactured by Tektronix), and the voltage (initial value Vcom) at which the flicker was minimized was set. This set value was set as an offset DC voltage.

  Using an external function generator, a driving frequency of 30 Hz rectangular wave was input to the liquid crystal display device of Example 1. Ten minutes later, the voltage (Vcom) at which flicker was minimized was measured using an oscilloscope, and then returned to the offset DC voltage, and the input of the driving frequency of the 30 Hz rectangular wave to the liquid crystal display device of Example 1 was resumed. Such Vcom measurement was performed for 2 hours, and the difference between Vcom after 2 hours and the initial value Vcom was calculated as the Vcom drift amount. For the liquid crystal display devices of Examples 2 to 11, the Vcom drift amount was calculated as described above. The results are listed in Table 2 below.

<Evaluation 2: Visual confirmation of flicker during low frequency driving>
The flicker state was visually determined using an oscilloscope under the same measurement conditions as in Evaluation 1 except that the driving frequency was set to 1 Hz.

<Evaluation 3: Resistivity measurement of photo-alignment film>
On the ITO layer of a non-alkali glass substrate (surface resistance ≦ 30Ω / sq, ITO film thickness 90 nm, manufactured by Geomatic) with an ITO film formed on the surface layer, each of the coating liquids of Examples 1 to 11 was applied. Was applied so that the film thickness was 200 nm, and imidization was performed by heating at 230 ° C. for 10 minutes.

Each imidized film was subjected to a photo-alignment treatment using polarized ultraviolet rays in the region of 254 nm to 365 nm. A short arc light source (UXM-5000BY, manufactured by Ushio Electric) was used for the photo-alignment treatment. The amount of irradiation with polarized ultraviolet rays in the photo-alignment treatment was about 7 J / cm ² . The amount of irradiation is a value measured by an integrating illuminometer (manufactured by USHIO INC., UVD-S254 sensor).

The imidized film after the photo-alignment treatment was heated at 230 ° C. for 30 minutes to form a photo-alignment film.
A circular aluminum electrode having a diameter of 0.8 mm on a photo-alignment film formed on an alkali-free glass substrate, and a C-shaped aluminum electrode spaced apart from the circular electrode (aluminum circular electrode with a guard ring) Was formed by mask vacuum deposition so as to have a film thickness of 0.3 μm.
A part of the photo-alignment film on the outer peripheral side of the C-shaped aluminum electrode was removed, and a part of the ITO layer was exposed. A silver paste for stabilizing the contact with the probe was applied to the exposed part of the ITO layer. This substrate was used as a substrate for measuring the resistivity of the photo-alignment film.

Such a substrate for resistivity measurement is placed on an LED backlight with an illuminance of 10000 cd / m ² with an alkali-free glass substrate on the backlight side, and a probe on the anode side of a high resistance meter (Agilent 4339B) is circular. The high resistance meter cathode side probe was applied to the silver paste portion, a voltage of 0.2 V to 2 V was applied at intervals of 0.2 V every 10 seconds, and the current value was measured by the two-terminal method. . This measurement was performed at a temperature of 25 ° C. and a relative humidity of 60%.
The resistivity ρ [Ωcm] was calculated by the following equation, where V is the horizontal axis, I is the vertical axis, and R is the reciprocal of the slope of the plot.
ρ = R · S / d
In the formula, d is the film thickness (200 nm) of the photo-alignment film, and S is the area of the electrode (2 cm ² ). The results are also shown in Table 2 below.

As described above, Examples 1 to 11 were evaluated in the following four stages based on the results of Evaluations 1 to 3.
A: Display abnormality such as DC afterimage and flicker during low frequency driving was not observed at all in the liquid crystal display device.
B: Display anomalies such as DC afterimage and flicker during low-frequency driving were not observed in the liquid crystal display device to the extent that there was no problem.
C: Display abnormality such as DC afterimage or flicker during low frequency driving was observed in the liquid crystal display device.
D: Flicker during low frequency driving was visually recognized on the liquid crystal display device.
The results are also shown in Table 2.

Diamines in the polyamic acid-based compounds of Synthesis Examples 3 and 6 to 8 for forming the lower layer in the varnish for photo-alignment films used for forming the photo-alignment films of the liquid crystal display devices of Examples 2 and 5 to 7. When the molar percentage of the skeleton derived from the compound is 100 mol%, the molar percentage of the skeleton derived from the diamine compound represented by the above formula (4) in each polyamic acid compound is 0 mol% and 10 mol%, respectively. 20 mol% and 50 mol%.
Examples 2 and 5 containing a polyamic acid-based compound in which the molar percentage of the skeleton derived from the diamine compound represented by the above formula (4) in each polyamic acid-based compound is 0 mol% and 10 mol%, respectively, as a lower layer component The liquid crystal display device provided with the photo-alignment film formed from the varnish for photo-alignment film has a mole percentage of the skeleton derived from the diamine compound represented by the above formula (4) in each polyamic acid-based compound of 20 mol%. The amount of Vcom drift after 2 hours as compared with a liquid crystal display device comprising a photo-alignment film formed from the varnish for photo-alignment films of Examples 6 and 7 containing a polyamic acid compound of 50 mol% as a lower layer component Is suppressed to a low level, and display abnormality such as a DC afterimage is suppressed or eliminated.

In the varnish for photo-alignment films used for forming the photo-alignment film of the liquid crystal display device of Examples 1 to 4, derived from the tetracarboxylic acid compound in each of the polyamic acid compounds in Synthesis Examples 2 to 5 for forming the lower layer When the molar percentage of the skeleton is 100 mol%, the molar percentage of the skeleton derived from the tetracarboxylic acid compound having the cyclobutane skeleton represented by the above formula (3-1) in each polyamic acid compound is 0 mol. %, 20 mol%, 30 mol%, and 50 mol%.
In each polyamic acid compound, the polyamic acid compound in which the molar percentage of the skeleton derived from the tetracarboxylic acid compound having the cyclobutane skeleton represented by the above formula (3-1) is 0 mol% and 20 mol%, respectively, is the lower layer. The liquid crystal display device provided with the photo-alignment film formed from the varnish for photo-alignment films of Examples 2 and 3 including as components has a cyclobutane skeleton represented by the above formula (3-1) in each polyamic acid compound. A photo-alignment film formed from the varnish for photo-alignment films of Examples 4 and 5 containing, as a lower layer component, a polyamic acid compound in which the molar percentage of the skeleton derived from the tetracarboxylic acid compound is 30 mol% and 50 mol%, respectively. Compared with the liquid crystal display device provided, the Vcom drift amount after 2 hours was suppressed to be low, and display abnormality such as a DC afterimage was suppressed or eliminated.

In the varnish for photo-alignment film used to form the photo-alignment film of the liquid crystal display device of Example 1, Example 10, Example 11, tetra in each polyamic acid compound of Synthesis Examples 2, 10, 11 for forming the lower layer When the mole percentage of the skeleton derived from the carboxylic acid compound is 100 mol%, the mole percentage of the skeleton derived from pyromellitic dianhydride represented by the above formula (3-2) in each polyamic acid compound is as follows: They are 0 mol%, 10 mol%, and 20 mol%, respectively.
A polyamic acid compound in which the molar percentage of the skeleton derived from pyromellitic dianhydride represented by the above formula (3-2) in each polyamic acid compound is 0 mol% and 10 mol%, respectively, is used as a lower layer component. The liquid crystal display device provided with the photo-alignment film formed from the varnish for photo-alignment films of Examples 1 and 10 is derived from pyromellitic dianhydride represented by the above formula (3-2) in the polyamic acid compound. The resistance of the photo-alignment film as compared with a liquid crystal display device comprising a photo-alignment film formed from the varnish for the photo-alignment film of Example 11 containing a polyamic acid compound having a skeleton percentage of 20 mol% as a lower layer component Since the rate is high, display anomalies such as flicker during low frequency driving are suppressed or eliminated.

The varnish for photo-alignment film used for forming the photo-alignment film of the liquid crystal display devices of Examples 2 and 9 contains 60% by weight and 40% by weight of the polyamic acid compound forming the lower layer, respectively.
A liquid crystal display device comprising a photo-alignment film formed from the varnish for photo-alignment film of Example 2 containing 60% by weight of the polyamic acid-based compound forming the lower layer includes 40% by weight of the polyamic acid-based compound forming the lower layer. Compared with a liquid crystal display device comprising a photo-alignment film formed from the photo-alignment film varnish of Example 9, the proportion of the imidized polyamic acid compound (upper layer) that is easily decomposed by the photo-alignment treatment is reduced. Display abnormality such as DC afterimage was suppressed.

  As mentioned above, although some embodiment of this invention was described, these embodiment was shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DSP ... Liquid crystal display device PNL ... Display panel 1 ... Flexible printed circuit board 2 ... IC chip 3 ... Circuit board SUB1 ... First substrate SUB2 ... Second substrate MA ... Mounting part LC ... Liquid crystal layer LM ... Liquid crystal molecule SE ... Seal LS ... Light shielding layer SP1 to SP4 ... Spacer DA ... Display part NDA ... Non-display part PX ... Pixel IL ... Illumination device First polarizing plate ... PL1 Second polarizing plate ... PL2 First optical element ... OD1 Second optical element ... OD2 10 ... First DESCRIPTION OF SYMBOLS 1 Insulating substrate 11-16 ... Insulating film 20 ... 2nd insulating substrate BM ... Light shielding film AL1 ... 1st orientation film AL2 ... 2nd orientation film ML1, ML2 ... Metal wiring S1, S2 ... Signal line CF ... Color filter OC ... Over Coat layer CE ... Common electrode PE ... Pixel electrode Upper layer ... AL1-1 Lower layer ... AL1-2

Claims (9)

A first polyamic acid-based compound that is a polyamic acid or a polyamic acid ester in an organic solvent, and a second polyamic acid-based compound that is a polyamic acid or a polyamic acid ester having a higher polarity than the first polyamic acid-based compound; Containing
The second polyamic acid compound is present in a larger amount than the first polyamic acid compound,
In the first polyamic acid compound,
When the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the first polyamic acid compound is 100 mol%, the following formula (1) in the first polyamic acid compound:

(In Formula (1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively) The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula is 50 mol% or more, and the molar percentage of the skeleton derived from the diamine compound in the first polyamic acid compound is 100 mol%. And the following formula (2) in the first polyamic acid-based compound:

(In the formula (2), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or The mole percentage of the skeleton derived from the diamine compound is 10 mol%, which is an aromatic group containing a nitro group, and K is an organic group containing a primary amino group or a secondary amino group. And
In the second polyamic acid compound,
When the molar percentage of the skeleton derived from the tetracarboxylic acid compound in the second polyamic acid compound is 100 mol%, the following formula (3-1) in the second polyamic acid compound:

(In Formula (3-1), R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl group), and R ^a is hydrogen or an alkyl group, respectively. The molar percentage of the skeleton derived from the tetracarboxylic acid compound having a cyclobutane skeleton represented by the formula (2) is 20 mol% or less, and the following formula (3-2) in the second polyamic acid-based compound:

(In formula (3-2), R ¹ and R ² are each independently derived from pyromellitic dianhydride represented by —COOH or COOR (where R is an alkyl group)). The molar percentage of the skeleton is 10 mol% or less, and when the molar percentage of the skeleton derived from the diamine compound in the second polyamic acid compound is 100 mol%, the following formula in the second polyamic acid compound (4):

(In the formula (4), J is Ar ^1, or a ^{Ar 2 -K-Ar 3, Ar} 1, Ar 2 and Ar ³ each independently, a primary amino group, secondary amino group, or The mole percentage of the skeleton derived from the diamine compound is 10 mol%, which is an aromatic group containing a nitro group, and K is an organic group containing a primary amino group or a secondary amino group. The varnish for photo-alignment films which is the following. The second polyamic acid-based compound has the following formula (10):

(In Formula (10), X ² is an alicyclic skeleton other than a cyclobutane skeleton, or a chain skeleton, and R ¹ and R ² are each independently —COOH or COOR (where R is an alkyl The varnish for a photoalignment film according to claim 1, comprising a skeleton derived from a tetracarboxylic acid compound represented by: The first polyamic acid-based compound has the following formula (5):

(In Formula (5), L is Ar < ⁴ > or Ar < ⁵ > -M-Ar < ⁶ >, Ar < ⁴ >, Ar < ⁵ > and Ar < ⁶ > are respectively independently a primary amino group, a secondary amino group, and An aromatic group not containing a nitro group, and M is an organic group not containing a primary amino group and a secondary amino group).
The second polyamic acid-based compound has the following formula (11-1):

(In Formula (11-1), L is Ar ⁴ or Ar ⁵ -M-Ar ⁶ , and Ar ⁴ , Ar ⁵ and Ar ⁶ are each independently a primary amino group or a secondary amino group. Or an aromatic group containing no nitro group, and M is an organic group containing no primary amino group and no secondary amino group). 2. A varnish for a photo-alignment film according to 2.   The M in the formula (5) and the M in the formula (11-1) are each independently an organic group composed of oxygen, nitrogen, sulfur, carbon, hydrogen, or a combination of two or more thereof. Varnish for photo-alignment film. The second polyamic acid-based compound has the following formula (11-2):

(In the formula (11-2), L ¹ is oxygen and / or an organic group containing fluorine) according to claim 1 comprising a backbone derived from a diamine compound represented by Varnish for photo-alignment film. A first substrate having an alignment film;
A second substrate disposed opposite to the alignment film side of the first substrate;
A liquid crystal layer disposed between the first substrate and the second substrate;
The said alignment film is a liquid crystal display device containing the imidized material of the varnish for optical alignment films as described in any one of Claims 1-5.   The liquid crystal display according to claim 6, wherein the alignment film includes an upper layer and a lower layer, the upper layer includes an imidized product of the first polyamic acid-based compound, and the lower layer includes an imidized product of the second polyamic acid-based compound. apparatus.   The liquid crystal display device according to claim 7, wherein the lower layer is thicker than the upper layer. The liquid crystal display device according to claim 6, wherein the alignment film has a resistivity of 9.0 × 10 ¹⁴ Ω · cm or more.

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