TWI735635B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

A liquid crystal alignment agent, which is characterized by containing at least one polymer selected from the group consisting of polyimine and polyimide precursors, and a solvent containing the following groups (A) and (B) Organic solvent, 　　 group (A): a solvent selected from at least one of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone; 　　 group (B): select At least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone, and 2-methyl-2-hexanol.

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element

[0001] The present invention relates to a liquid crystal alignment agent suitable for coating by an inkjet method, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element.

[0002] As the liquid crystal alignment film, so-called polyimide-based liquid crystal alignment films are widely used, which are mainly composed of polyimide precursors such as polyimide acid or a solution of soluble polyimide. The liquid crystal alignment agent is coated and fired. However, as a method of forming the above-mentioned liquid crystal alignment film, spin coating, dip coating, flexographic printing, and the like are generally known. In fact, most of them use coating by flexographic printing. In addition, due to the following problems: flexographic printing requires a variety of resin plates depending on the type of liquid crystal panel; the exchange of the plates in the manufacturing step is complicated; in order to stabilize the film formation step, it must be performed in pseudo Film formation on the substrate; plate production has become a factor in the increase in the manufacturing cost of liquid crystal display panels, etc. Therefore, in recent years, coating by the inkjet method (hereinafter referred to as inkjet coating) has gradually attracted attention. [0003] The liquid crystal alignment film formed by various coating methods requires that the unevenness of the film thickness inside the coating surface be small and the peripheral portion of the coating is required in terms of display uniformity and influence on electrical characteristics The precision of film formation is high. In particular, if there is unevenness in the film thickness, differences in display quality due to unevenness may be the main cause of display defects. In addition, it may be the total amount of ionic impurities generated from the membrane, and it may also become the main cause of the influence on the alignment membrane.　　[0004] For the above reasons, the solvent contained in the alignment agent is preferably one that is less likely to cause uneven coating and can be uniformly coated.　　[0005] In order to improve the film formation accuracy of the coating peripheral portion, a method of enclosing the alignment film within a specified range by a structure has been proposed (Patent Document 1, Patent Document 2, Patent Document 3). However, these methods have the disadvantage of requiring additional structures. [Prior Art Document] [Patent Document] 　　[0006] 　　 [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-361623 [Patent Document 2] Japanese Patent Application Publication No. 2008-145461 [Patent Document 3] Japanese Patent Application Publication No. 2010-281925 Bulletin

[Problem to be solved by the invention] 　　[0007] Therefore, the object of the present invention is to provide a polyimide-based liquid crystal alignment agent, which can form the uniformity of the film thickness in the coating surface or the straight line of the coating peripheral portion It is a coating film with excellent properties, and the electrical characteristics of a liquid crystal display element are excellent.

As a result of repeated and intensive studies in order to achieve the above-mentioned object, the present inventor completed the present invention with the following as the gist.

The first aspect of the present invention to achieve the above object is a liquid crystal alignment agent characterized by containing at least one polymer selected from the group consisting of polyimine and polyimine precursors, and the following The solvent of the solvent of group (A) and group (B), group (A): at least selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone One solvent; group (B): at least one selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol Of solvents.

The second aspect of the present invention that achieves the above object is the liquid crystal alignment agent of the first aspect, wherein the solvent of the aforementioned group (A) contains a solvent selected from the group consisting of N-methyl-2-pyrrolidone and γ-butyrolone At least one of the group of esters.

The third aspect of the present invention that achieves the above object is a liquid crystal alignment agent such as the first aspect or the second aspect, wherein the solvent of the aforementioned group (A) is 50% to 95% by weight relative to the total solvent amount.

The fourth aspect of the present invention that achieves the above-mentioned object is a liquid crystal alignment agent of any one of the first aspect to the third aspect, wherein the solvent of the aforementioned group (B) is 5% by weight relative to the total solvent amount. 50% by weight.

The fifth aspect of the present invention that achieves the above-mentioned object is a liquid crystal alignment agent of any one of the first aspect to the fourth aspect, which contains 1% to 5% by mass of the aforementioned polymer.

The sixth aspect of the present invention that achieves the above-mentioned object is a liquid crystal alignment agent of any one of the first aspect to the fifth aspect, which contains 95% to 99% by mass of the aforementioned solvent.

The seventh aspect of the present invention that achieves the above object is a liquid crystal alignment film, which is characterized by a liquid crystal alignment agent of any one of the first aspect to the sixth aspect.

The eighth aspect of the present invention that achieves the above-mentioned object is a liquid crystal display element, which is characterized by having the liquid crystal alignment film of the seventh aspect.

The liquid crystal alignment agent of the present invention, particularly when inkjet coating is applied, can provide a coating film with excellent linearity in the coating peripheral portion. Furthermore, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention has excellent voltage retention characteristics.

[Best form to implement the invention]

The liquid crystal alignment agent of the present invention is characterized by containing at least one polymer selected from the group consisting of polyimine and polyimide precursors, and the following group (A) and group (B) Solvent organic solvent. Hereinafter, the liquid crystal alignment agent of the present invention will be described in detail.

<Organic Solvent>

The liquid crystal alignment agent of the present invention contains the following group (A) and the following The organic solvent of the solvent of group (B).

Group (A): At least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone.

Group (B): At least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone, and 2-methyl-2-hexanol.

<Solvent for Group (A)>

The solvent of group (A) contained in the organic solvent of the present invention is selected from N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone (N-ethyl-2-pyrrolidone) and γ-butyrolactone (γ-butyrolactone) at least one kind of solvent. These systems are mainly solvents for dissolving polymers. Among them, from the viewpoint of solubility, at least one selected from the group consisting of N-methyl-2-pyrrolidone and γ-butyrolactone is preferred.

The content of the solvent of the aforementioned group (A) is preferably 50% by weight to 95% by weight relative to the total solvent amount from the viewpoint of the solubility of the aligning agent.

<Solvent of Group (B)>

The solvent of group (B) contained in the organic solvent of the present invention is selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl- At least one solvent of 2-hexanol. These systems are mainly used to provide solvents with good coating properties.

The solvent content of the aforementioned group (B), from the viewpoint of the stability of the solution, is 5 wt% to 50 wt% relative to the total solvent content. good.

<Other solvents>

The liquid crystal alignment agent of the present invention may contain solvents other than the above-mentioned solvents (hereinafter also referred to as other solvents) to the extent that the effects of the present invention can be exerted. Examples of other solvents are listed below, but they are not limited to them.

For example, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-ethyl-2-pyrrolidone, N- Methyl caprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfide, dimethyl sulfide, 1,3-dimethyl-2-imidazolinone, 3 -Methoxy-N,N-dimethyl propanamide, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol , 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 2-butoxy-1-propanol, 1-phenoxy -2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetic acid Ester, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, diacetone alcohol, etc.

Examples of solvent combinations that are preferable as other solvents, and combinations of the aforementioned group (A) and the aforementioned group (B) are as follows.

[0031] 上述式(1)中，X₁ 係表示來自四羧酸衍生物之4價的有機基，Y₁ 係表示來自二胺之2價的有機基，R₁ 係表示氫原子或碳原子數1~5的伸烷基。就加熱時進行醯亞胺化反應之容易度的觀點而言，R₁ 係以氫原子、甲基、乙基為較佳，以氫原子或甲基為又較佳。 　　A₁ 及A₂ 係分別獨立為氫原子、或碳數1~5的烷基、碳數2~5的烯基、碳數2~5的炔基。就液晶配向性之觀點而言，A₁ 及A₂ 係以氫原子、或甲基為較佳。 　　[0032] 以下，對於成為製成聚合物的原料之各成分來進行詳述。 　　[0033] ＜二胺＞ 　　本發明之液晶配向劑中所使用的二胺成分的構造並無特別限定。 　　[0034] 具有上述式(1)的構造的聚合物之聚合時所使用的二胺，可用以下式(2)為一般式來表示。 　　[0035]

[0036] 上述式(2)的A₁ 及A₂ (亦包含該等較佳的例子)係與上述式(1)的A₁ 及A₂ 為相同的定義。若示例Y₁ 的構造時，則如下述般。 　　[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] 上述式(Y-165)及上述式(Y-166)中，n係1~6的整數。 　　[0057]

[0058] 上述式(Y-175)、上述式(Y-176)、上述式(Y-179)及上述式(Y-180)中之Boc係表示tert-丁氧基羰基。 　　[0059] ＜四羧酸衍生物＞ 　　本發明之液晶配向劑中所含有作為用於製作具有上述式(1)的構造單位的聚合物之四羧酸衍生物成分，不僅是四羧酸二酐，亦可使用該四羧酸衍生物的四羧酸、四羧酸二鹵化物化合物、四羧酸二烷基酯化合物或四羧酸二烷基酯二鹵化物化合物。 　　[0060] 作為四羧酸二酐或該衍生物，以使用選自下述式(3)所表示的四羧酸二酐或該衍生物之至少1種為又較佳。 　　[0061]

[0062] 上述式(3)中，X₁ 係具有脂環式構造之4價的有機基，該構造並無特別限定。作為具體例可舉出下述式(X1-1)~下述式(X1-44)。 　　[0063]

[0064] 上述式(X1-1)~上述式(X1-4)中，R₃ 至R₂₃ 係分別獨立為氫原子、鹵素原子、碳數1~6的烷基、碳數2~6的烯基、碳數2~6的炔基、含有氟原子的碳數1~6之1價的有機基、或苯基，且可相同亦可不同。就液晶配向性之觀點而言，R₃ 至R₂₃ 係以氫原子、鹵素原子、甲基、或乙基為較佳，以氫原子、或甲基為又較佳。作為上述式(X1-1)之具體的構造，可舉出下述式(X1-1-1)~下述式(X1-1-6)所表示的構造。就液晶配向性及光反應的感度之觀點而言，以下述式(X1-1-1)為特佳。 　　[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] ＜聚醯胺酸酯(polyamic acid ester)之製造方法＞ 　　本發明中所使用的聚醯亞胺前驅物之一的聚醯胺酸酯，可用以下所表示的(1)、(2)或(3)之方法來合成。 　　[0072] (1)由聚醯胺酸來合成之情形時 　　聚醯胺酸酯係可藉由將由四羧酸二酐與二胺所得到的聚醯胺酸予以酯化來合成。 　　[0073] 具體而言，可藉由將聚醯胺酸與酯化劑在有機溶劑之存在下，在-20℃~150℃、較佳為在0℃~50℃下，以30分鐘~24小時、較佳為1小時~4小時使其反應來合成。 　　[0074] 作為酯化劑，以藉由純化可容易地除去者為較佳，可舉出N,N-二甲基甲醯胺二甲基縮醛、N,N-二甲基甲醯胺二乙基縮醛、N,N-二甲基甲醯胺二丙基縮醛、N,N-二甲基甲醯胺二新戊基丁基縮醛、N,N-二甲基甲醯胺二-t-丁基縮醛、1-甲基-3-p-甲苯基三氮烯、1-乙基-3-p-甲苯基三氮烯、1-丙基-3-p-甲苯基三氮烯、4-(4,6-二甲氧基-1,3,5-三嗪-2-基)-4-甲基嗎啉鹽酸鹽等。酯化劑的添加量，相對於聚醯胺酸的重複單位1莫耳，以2莫耳當量~6莫耳當量為較佳。 　　[0075] 上述之反應中使用的溶劑，就聚合物的溶解性而言，以N,N-二甲基甲醯胺、N-甲基-2-吡咯啶酮、或γ-丁內酯為較佳，該等係可1種或亦可混合2種以上來使用。合成時的濃度，就不易引起聚合物的析出、且容易得到高分子量體之觀點而言，以1質量%~30質量%為較佳，以5質量%~20質量%為又較佳。 　　[0076] (2)藉由四羧酸二酯二氯化物與二胺之反應來合成之情形時 　　聚醯胺酸酯係可由四羧酸二酯二氯化物與二胺來合成。 　　[0077] 具體而言，可藉由將四羧酸二酯二氯化物與二胺在鹼與有機溶劑之存在下，在-20℃~150℃、較佳為0℃~50℃下，以30分鐘~24小時、較佳為1小時~4小時使其反應來合成。 　　[0078] 前述鹼係可使用吡啶、三乙胺、4-二甲胺吡啶等，但為了反應穏定地進行，以吡啶為較佳。鹼的添加量，就容易除去的量、且容易得到高分子量體之觀點而言，相對於四羧酸二酯二氯化物以2倍莫耳~4倍莫耳為較佳。 　　[0079] 上述之反應中使用的溶劑，就單體及聚合物的溶解性而言，以N-甲基-2-吡咯啶酮、或γ-丁內酯為較佳，該等係可1種或亦可混合2種以上來使用。合成時的聚合物濃度，就不易引起聚合物的析出、且容易得到高分子量體之觀點而言，以1質量%~30質量%為較佳，以5質量%~20質量%為又較佳。又，為了防止四羧酸二酯二氯化物的水解，聚醯胺酸酯的合成中使用的溶劑，以盡可能脫水的狀態為較佳，並以在氮環境中防止外來氣體的混入為較佳。 　　[0080] (3)由四羧酸二酯與二胺來合成聚醯胺酸酯之情形時 　　聚醯胺酸酯係可藉由將四羧酸二酯與二胺予以縮聚合來合成。 　　[0081] 具體而言，可藉由將四羧酸二酯與二胺在縮合劑、鹼、及有機溶劑之存在下，在0℃~150℃、較佳為0℃~100℃下，以30分鐘~24小時、較佳為3小時~15小時使其反應來合成。 　　[0082] 前述縮合劑，可使用三苯基亞磷酸酯、二環己基碳二醯亞胺、1-乙基-3-(3-二甲胺丙基)碳二醯亞胺鹽酸鹽、N,N’-羰基二咪唑、二甲氧基-1,3,5-三嗪基甲基氯化嗎福啉鹽、O-(苯并三唑-1-基)-N,N,N’,N’-四甲基脲四氟硼酸鹽、O-(苯并三唑-1-基)-N,N,N’,N’-四甲基脲六氟磷酸鹽、(2,3-二氫-2-硫基-3-苯并

唑基)膦酸二苯酯等。縮合劑的添加量，相對於四羧酸二酯以2倍莫耳~3倍莫耳為較佳。 　　[0083] 前述鹼係可使用吡啶、三乙胺等的3級胺。鹼的添加量，就容易除去的量、且容易得到高分子量體之觀點而言，相對於二胺成分以2倍莫耳~4倍莫耳為較佳。 　　[0084] 又，上述反應中，藉由加入路易斯酸來作為添加劑，反應可有效率地進行。作為路易斯酸係以氯化鋰、溴化鋰等的鹵化鋰為較佳。路易斯酸的添加量，相對於二胺成分以0倍莫耳~1.0倍莫耳為較佳。 　　[0085] 在上述3種的聚醯胺酸酯的合成方法中，由於可得到高分子量的聚醯胺酸酯，故以上述(1)或上述(2)之合成法為特佳。 　　[0086] 以如上述般之方式所得到的聚醯胺酸酯的溶液，藉由一邊充分攪拌一邊注入至不良溶劑中，從而可使聚合物析出。進行數次的析出並用不良溶劑洗淨後，在常溫或加熱乾燥後可得到經純化的聚醯胺酸酯的粉末。不良溶劑並無特別限定，可舉出水、甲醇、乙醇、己烷、丁基溶纖劑、丙酮、甲苯等。 　　[0087] ＜聚醯胺酸之製造方法＞ 　　本發明中所使用的聚醯亞胺前驅物的聚醯胺酸，可藉由下述所表示之方法來合成。 　　[0088] 具體而言，可藉由將四羧酸二酐與二胺在有機溶劑之存在下，在-20℃~150℃、較佳為0℃~50℃下，以30分鐘~24小時、較佳為1小時~12小時使其反應來合成。 　　[0089] 上述之反應中使用的有機溶劑，就單體及聚合物的溶解性而言，以N,N-二甲基甲醯胺、N-甲基-2-吡咯啶酮、或γ-丁內酯為較佳，該等係可1種或亦可混合2種以上來使用。聚合物的濃度，就不易引起聚合物的析出、且容易得到高分子量體之觀點而言，以1質量%~30質量%為較佳，以5質量%~20質量%為又較佳。 　　[0090] 以如上述般之方式所得到的聚醯胺酸係可藉由一邊充分攪拌反應溶液一邊注入至不良溶劑中使聚合物析出並回收。又，進行數次的析出並用不良溶劑洗淨後，藉由在常溫或加熱乾燥可得到經純化的聚醯胺酸的粉末。不良溶劑並無特別限定，可舉出水、甲醇、乙醇、己烷、丁基溶纖劑、丙酮、甲苯等。 　　[0091] ＜聚醯亞胺之製造方法＞ 　　本發明中所使用的聚醯亞胺，可藉由將前述聚醯胺酸酯或聚醯胺酸予以醯亞胺化來製造。由聚醯胺酸酯來製造聚醯亞胺之情形時，以在前述聚醯胺酸酯溶液中添加鹼性觸媒、或在於有機溶劑中溶解聚醯胺酸酯樹脂粉末而得的聚醯胺酸溶液中添加鹼性觸媒的化學性醯亞胺化為簡便。化學性醯亞胺化係因在較低溫度下進行醯亞胺化反應，且在醯亞胺化的過程中不易引起聚合物的分子量降低，故為較佳。 　　[0092] 化學性醯亞胺化係可藉由將欲醯亞胺化的聚醯胺酸酯，在有機溶劑中於鹼性觸媒之存在下攪拌來進行。作為有機溶劑，可使用於前述之聚合反應時所使用的溶劑。作為鹼性觸媒可舉出吡啶、三乙胺、三甲胺、三丁胺、三辛胺等。其中，三乙胺由於具有使反應進行所需之充分的鹼性，故為較佳。 　　[0093] 進行醯亞胺化反應時的溫度係-20℃~140℃，較佳為0℃~100℃，反應時間係以1小時~100小時來進行。鹼性觸媒的量係聚醯胺酸酯基的0.5莫耳倍~30莫耳倍、較佳為2莫耳倍~20莫耳倍。所得到的聚合物的醯亞胺化率，可藉由調節觸媒量、溫度、反應時間來控制。因為醯亞胺化反應後的溶液中會殘留添加的觸媒等，故較佳藉由下述之手段來回收所得到的醯亞胺化聚合物，並以有機溶劑再溶解而製成本發明之液晶配向劑。 　　[0094] 由聚醯胺酸來製造聚醯亞胺之情形時，對於以二胺成分與四羧酸二酐的反應而得到的前述聚醯胺酸的溶液添加觸媒的化學性醯亞胺化為簡便。化學性醯亞胺化係因在較低溫度下進行醯亞胺化反應，且在醯亞胺化的過程不易引起聚合物的分子量降低，故為較佳。 　　[0095] 化學性醯亞胺化係可藉由將欲醯亞胺化的聚合物，在有機溶劑中於鹼性觸媒和酸酐之存在下攪拌來進行。作為有機溶劑，可使用於前述之聚合反應時所使用的溶劑。作為鹼性觸媒可舉出吡啶、三乙胺、三甲胺、三丁胺、三辛胺等。其中，吡啶由於具有使反應進行所需之適度的鹼性，故為較佳。又，作為酸酐可舉出乙酸酐、偏苯三甲酸酐、焦蜜石酸二酐等，其中，使用乙酸酐時於反應結束後容易純化，故為較佳。 　　[0096] 進行醯亞胺化反應時的溫度係以-20℃~140℃、較佳為0℃~100℃，反應時間係可以1小時~100小時下來進行。鹼性觸媒的量係以醯胺酸基的0.5莫耳倍~30莫耳倍、較佳為2莫耳倍~20莫耳倍，酸酐的量係以醯胺酸基的1莫耳倍~50莫耳倍，較佳為3莫耳倍~30莫耳倍。所得到的聚合物的醯亞胺化率，可藉由調節觸媒量、溫度、反應時間來控制。 　　[0097] 聚醯胺酸酯或聚醯胺酸之醯亞胺化反應後的溶液中，因為會殘留添加的觸媒等，故較佳藉由下述之手段來回收所得到的醯亞胺化聚合物，並以有機溶劑再溶解而製成本發明之液晶配向劑。 　　[0098] 以如上述般之方式所得到的聚醯亞胺的溶液，藉由一邊充分攪拌一邊注入至不良溶劑中，從而可使聚合物析出。進行數次的析出並用不良溶劑洗淨後，常溫或加熱乾燥，可得到經純化的聚醯胺酸酯的粉末。 　　[0099] 前述不良溶劑並無特別限定，可舉出甲醇、丙酮、己烷、丁基溶纖劑、庚烷、甲基乙基酮、甲基異丁基酮、乙醇、甲苯、苯等。 　　[0100] ＜液晶配向劑＞ 　　本發明中所使用的液晶配向劑，其係具有特定構造的聚合物被溶解於有機溶劑中而成的溶液形態。本發明中所記載之聚醯亞胺前驅物及聚醯亞胺的分子量，以重量平均分子量計以2,000~500,000為較佳，又較佳為5,000~300,000，更佳為10,000~100,000。又，數平均分子量係較佳為1,000~250,000，又較佳為2,500~150,000，更佳為5,000~50,000。 　　[0101] 本發明中所使用的液晶配向劑的聚合物的濃度，可依據欲形成的塗膜厚度的設定來做適當變更，就形成均勻且無缺陷的塗膜之點而言，以1重量%以上為較佳，就溶液的保存穩定性之點而言，以10重量%以下為較佳。 　　[0102] 本發明之液晶配向劑亦可含有矽烷偶合劑或交聯劑等的各種添加劑。矽烷偶合劑係以提高塗佈液晶配向劑的基板與形成於該基板上的液晶配向膜的密著性為目的而添加。矽烷偶合劑係可添加現有者。 　　[0103] 上述矽烷偶合劑的添加量若過多時，未反應物會對液晶配向性造成不良影響，若過少時則無法顯現對密著性的效果，因此相對於聚合物的固形分以0.01重量%~5.0重量%為較佳，以0.1重量%~1.0重量%為又較佳。添加上述矽烷偶合劑之情形時，為了防止聚合物的析出，以在添加前述用於提升塗膜均勻性的溶劑之前來添加矽烷偶合劑為較佳。 　　[0104] 又，為了於燒成塗膜時使聚醯亞胺前驅物之醯亞胺化效率良好地進行，本發明之液晶配向劑中亦可添加醯亞胺化促進劑。作為醯亞胺化促進劑係可使用現有者。 　　[0105] 添加醯亞胺化促進劑之情形時，由於存在因加熱而醯亞胺化會進行之可能性，故以使用良溶劑及不良溶劑稀釋後添加為較佳。 　　[0106] ＜液晶配向膜＞ 　　本發明之液晶配向膜，係將上述液晶配向劑塗佈於基板，進行乾燥、燒成而得到之膜。作為塗佈本發明之液晶配向劑的基板，只要是透明性高的基板則無特別限定，可使用玻璃基板、氮化矽基板、丙烯酸基板、聚碳酸酯基板等的塑膠基板等，就製程簡化之觀點而言，以使用已形成用於驅動液晶的ITO電極等的基板為較佳。又，反射型液晶顯示元件中，若僅為單側之基板時，亦可使用矽晶圓等之不透明物，此情形之電極亦可使用鋁等將光反射之材料。 　　[0107] 作為本發明之液晶配向劑之塗佈方法，可使用旋轉塗佈法、印刷法等，但如上述般特別是本發明之液晶配向劑為特別適合於噴墨法。藉由噴墨法來塗佈本發明之液晶配向劑從而形成塗佈膜之情形時(噴墨塗佈)，可得到塗佈面內的膜厚均勻性、或塗佈周邊部的直線性為優異的塗佈膜。 　　[0108] 塗佈本發明之液晶配向劑後的乾燥、燒成步驟係可選擇任意的溫度與時間。通常，為了充分地除去所含有的有機溶劑，在50℃~120℃下使其乾燥1分鐘~10分鐘，之後在150℃~300℃下燒成5分鐘~120分鐘。燒成後的塗膜的厚度並無特別限定，過薄時會有液晶顯示元件的可靠性降低之情形，因此為5nm~300nm、較佳為10nm~ 200nm。 　　[0109] 本發明之液晶配向處理劑於基板上塗佈並燒成後，利用摩擦處理或光配向處理等來進行配向處理，或在垂直配向用途等中可不經配向處理而使用作為液晶配向膜。 　　[0110] ＜液晶顯示元件＞ 　　本發明之液晶顯示元件係藉由上述之手法，由本發明之液晶配向劑得到附有液晶配向膜的基板並進行配向處理後，用周知的方法來製作液晶晶胞從而作為液晶顯示元件。 　　[0111] 液晶晶胞之製造方法並無特別限定，但若要舉出一例時通常為將已形成液晶配向膜的1對基板使液晶配向膜面作為內側，且夾持著較佳為1μm~30μm，又較佳為2μm~10μm的間隔件進行設置後，用密封劑固定周圍並注入液晶來進行密封之方法。對於液晶封入之方法並無特別限制，可示例有將製作的液晶晶胞內進行減壓後注入液晶之真空法、滴入液晶後進行密封之滴入法等。 [實施例] 　　[0112] 以下舉出實施例，進而具體地說明本發明。但，本發明理當不限定於該等之實施例中而被解釋。 　　[0113] 尚，實施例及比較例中使用的縮寫、及各特性之測定方法係如下述般。 　　1,3DMCBDA：1,3-二甲基1,2,3,4環丁烷四羧酸二酐 　　CBDA：1,2,3,4-環丁烷四羧酸二酐 　　DA-1：下述式DA-1的二胺 　　DA-2：下述式DA-2的二胺 　　DA-3：下述式DA-3的二胺 　　[0114]

[0115] 上述式DA-2及上述式DA-3中之Boc係表示tert-丁氧基羰基。 　　[0116] ＜溶劑＞ 　　NMP：N-甲基-2-吡咯啶酮 　　BCS：丁基溶纖劑 　　GBL：γ-丁內酯 　　BCA：丁基溶纖劑乙酸酯 　　PB：丙二醇單丁醚 　　DME：二丙二醇二甲醚 　　DEDG：二乙二醇二乙醚 　　DAA：二丙酮醇 　　4M4M2P：4-甲氧基-4-甲基-2-戊酮 　　4H2B：4-羥基-2-丁酮 　　2M2H：2-甲基-2-己醇 　　[0117] ＜黏度＞ 　　合成例中，聚合物溶液的黏度係使用E型黏度計TVE-22H(東機產業公司製)，在樣品量1.1mL、錐形轉子TE-1(1°34’、R24)、在溫度25℃下來進行測定。 　　[0118] ＜分子量＞ 　　合成例中，聚合物的分子量係藉由GPC(常溫凝膠滲透色譜法)裝置來進行測定，作為聚乙二醇、聚環氧乙烷換算值來算出數平均分子量(以下亦稱為Mn)與重量平均分子量(以下亦稱為Mw)。 　　GPC裝置：Shodex公司製(GPC-101) 　　管柱：Shodex公司製(KD803、KD805的串聯) 　　管柱溫度：50℃ 　　溶離液：N,N-二甲基甲醯胺(作為添加劑，溴化鋰-水合物(LiBr･H₂ O)為30mmol/L、磷酸酐結晶(o-磷酸)為30mmol/L、四氫呋喃(THF)為10ml/L) 　　流速：1.0ml/分鐘 　　檢量線製作用標準樣品：Tosoh公司製TSK標準聚環氧乙烷(重量平均分子量(Mw)約900,000、150,000、100,000、30,000)、及Polymer Laboratories公司製聚乙二醇(峰頂分子量(Mp)約12,000、4,000、1,000)。測定係為了避免波峰重疊，將混合900,000、100,000、12,000、1,000的4種類的樣品、及混合150,000、30,000、4,000的3種類的樣品之2種樣品分別來進行測定。 　　[0119] ＜合成例＞ (合成例1) 　　於附有攪拌裝置及氮導入管的50mL的四頸燒瓶中，量取DA-1 1.88g(7.70mmol)及DA-3 1.17g(2.11mmol)、DA-2 1.67g(4.20mmol)，加入NMP 40.00g，並一邊送氮一邊攪拌來使其溶解。一邊攪拌該二胺溶液一邊加入1,3DMCBDA 2.04g(9.10mmol)並進而攪拌，於黏度穩定後添加CBDA 0.62g(3.16mmol)，進而以固形分濃度成為15質量%之方式加入NMP，並以室溫下攪拌24小時，從而得到聚醯胺酸(PAA-1)的溶液。該聚醯胺酸溶液於25℃下之黏度為212mPa･S。 　　[0120] (合成例2) 　　於附有攪拌裝置及氮導入管的100mL的四頸燒瓶中，量取合成例1所得到的PAA-1 30g，以固形分濃度成為8質量%之方式加入NMP並稀釋。 　　[0121] 接下來，加入乙酸酐2.61g(25.5mmol)、吡啶0.67g(8.47mmol)並使其溶解。接下來，一邊攪拌該溶液一邊加熱至55℃，並使其反應3小時。將所得到的聚醯胺酸-可溶性聚醯亞胺酸溶液一邊攪拌一邊投入至全溶液之3.5倍等量的甲醇中並使其再沉澱。再沉澱後的粉體係藉由自然過濾或吸引過濾來進行過濾取得，之後進而分別將0.188l(5.86mmol)的甲醇分2次來洗淨，並使其乾燥藉此得到白色的聚醯胺酸-可溶性聚醯亞胺樹脂粉末(PWD-1)。該樹脂粉末的分子量為Mn＝13,493、Mw＝27,207。 　　[0122] 將上述所得到的PＷD-1溶解於NMP中，可得到固形分濃度12質量%的聚醯胺酸-可溶性聚醯亞胺樹脂粉末溶液(SPI-1)。 　　[0123] (實施例1) 　　於放入攪拌子的20ml樣品管中，量取合成例1所得到的聚醯胺酸溶液(PAA-1)6.75g，加入以NMP稀釋成1.0質量%的3-縮水甘油氧基丙基甲基二乙氧基矽烷溶液0.81g、NMP 6.84g。之後，加入DAA 3.60g並利用磁攪拌器攪拌30分鐘，從而得到液晶配向劑(A-1)。將液晶配向劑A-1在 -20℃下保管1週後，未發現固形物的析出為均勻的溶液。 　　[0124] (實施例2~實施例5、比較例1~比較例6) 　　除了使用聚醯胺酸-可溶性聚醯亞胺樹脂粉末溶液(SPI-1)來替代聚醯胺酸(PAA-1)、或使用下述表的溶劑來替代作為溶劑的DAA以外，進行與實施例1相同的操作，從而分別得到液晶配向劑(A-2)~(A-5)、(B-1)~(B-6)。將依據上述所得到的全部的液晶配向劑在-20℃下保管1週後，未發現固形物的析出為均勻的溶液。各個結果係表示於下述表1。 　　[0125] [表1]

[0126] 為了評估液晶晶胞的電特性，首先準備附有電極的基板。基板係30mm×40mm的大小，厚度為1.1mm的玻璃基板。於基板上形成膜厚35nm的ITO電極，電極為縱40mm、橫10mm的條紋圖案。 　　[0127] 接下來，將液晶配向劑使用1.0μm的過濾器進行過濾後，以旋轉塗佈塗佈於所準備的附有上述電極的基板上。在50℃的加熱板上使其乾燥5分鐘後，用230℃的IR式烘箱進行20分鐘燒成，形成膜厚100nm的塗膜，從而得到附有液晶配向膜的基板。使用人造絲布摩擦該液晶配向膜(輥直徑：120mm、輥旋轉數：1000rpm、移動速度：20mm/sec、壓入長度：0.4mm)後，在純水中超音波照射1分鐘來進行洗淨，並以鼓風除去水滴後，在80℃下乾燥15分鐘從而得到附有液晶配向膜的基板。準備2片該附有液晶配向膜的基板，在其中1片的液晶配向膜面上散布4μm的間隔件後，從其上方印刷密封劑，以摩擦方向為反向、且膜面相向之方式來黏貼另1片的基板後，使密封劑硬化從而製作空晶胞。藉由減壓注入法於該空晶胞注入液晶ML-7026-100(MERCK JAPAN製)，並密封注入口，從而得到液晶晶胞。之後，將所得到的液晶晶胞在120℃下加熱60分鐘，之後冷卻至室溫，進行晶胞之觀察後配向性為良好。 　　[0128] ＜電壓保持率之測定＞ (實施例6) 　　在60℃的溫度下對上述液晶晶胞外加1V的電壓60μs，並測定50ms後的電壓，將電壓能夠保持何種程度作為電壓保持率來進行計算。 　　[0129] 其結果，由配向劑A-1所成的配向膜在60℃下之電壓保持率為96.7%。 　　[0130] (實施例7~實施例10、比較例7~比較例12) 　　對於實施例2~實施例5、比較例1~比較例6所得到的配向劑(A-2)~配向劑(A-5)及配向劑(B-1)~配向劑(B-6)亦藉由相同的手法來製成液晶晶胞，並藉由實施例6所記載之測定方法來測定電壓保持率。各個的結果係表示於下述表2。 　　[0131] [表2]

[產業上利用性] 　　[0132] 可廣泛用於TN元件、STN元件、TFT液晶元件、進而用於垂直配向型的液晶顯示元件等。Examples include N,N-dimethylformamide, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diisobutylcarbinol, two Isopropyl ether, diisobutyl ketone, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 2-butanol Oxy-1-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-mono Diethyl ether-2-acetate, butylcellosolve acetate, dipropylene glycol, dipropylene glycol dimethyl ether, dipropylene glycol dimethyl-n-propyl ether, etc. [0028] <Polymer> The polymer contained in the liquid crystal alignment agent of the present invention is at least one polymer selected from the group consisting of polyimine and polyimide precursors. [0029] The polyimide precursor system can be represented by the following formula (1). [0030]

[0031] In the above formula (1), X ₁ represents a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ represents a divalent organic group derived from a diamine, and R ₁ represents a hydrogen atom or a carbon atom The number of alkylene groups from 1 to 5. From the viewpoint of the ease of the imidization reaction during heating, R ₁ is preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. A ₁ and A ₂ are each independently a hydrogen atom, or an alkyl group having 1 to 5 carbons, an alkenyl group having 2 to 5 carbons, and an alkynyl group having 2 to 5 carbons. From the viewpoint of liquid crystal orientation, A ₁ and A ₂ are preferably hydrogen atoms or methyl groups. [0032] Hereinafter, each component used as a raw material for the polymer will be described in detail. [0033] <Diamine> The structure of the diamine component used in the liquid crystal alignment agent of the present invention is not particularly limited. [0034] The diamine used in the polymerization of the polymer having the structure of the above formula (1) can be represented by the following formula (2) as a general formula. [0035]

_{[0036] A 1} and A _{2 of the} above formula (2) (also including these preferred examples) are the same definitions as _{A 1} and A _{2 of the above formula (1).} When the structure of Y ₁ is illustrated, it is as follows. [0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] In the above formula (Y-165) and the above formula (Y-166), n is an integer of 1 to 6. [0057]

[0058] The Boc in the above formula (Y-175), the above formula (Y-176), the above formula (Y-179) and the above formula (Y-180) represents a tert-butoxycarbonyl group. <Tetracarboxylic acid derivative> The tetracarboxylic acid derivative component contained in the liquid crystal alignment agent of the present invention as a polymer having the structural unit of the above formula (1) is not only tetracarboxylic dianhydride A tetracarboxylic acid, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, or a tetracarboxylic acid dialkyl ester dihalide compound of the tetracarboxylic acid derivative can also be used. [0060] As the tetracarboxylic dianhydride or the derivative, it is more preferable to use at least one selected from the tetracarboxylic dianhydride or the derivative represented by the following formula (3). [0061]

[0062] In the above formula (3), X ₁ is a tetravalent organic group having an alicyclic structure, and the structure is not particularly limited. As a specific example, following formula (X1-1)-following formula (X1-44) are mentioned. [0063]

[0064] In the above formula (X1-1) to the above formula (X1-4), R ₃ to R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbons, and an alkyl group having 2 to 6 carbons. An alkenyl group, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group may be the same or different. From the viewpoint of liquid crystal alignment, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. As a specific structure of the said formula (X1-1), the structure represented by following formula (X1-1-1)-following formula (X1-1-6) is mentioned. From the viewpoint of liquid crystal orientation and photoreaction sensitivity, the following formula (X1-1-1) is particularly preferred. [0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] <Method for producing polyamic acid ester> Polyamic acid ester, which is one of the polyimide precursors used in the present invention, can be represented by (1) and (2) below. ) Or (3). [0072] (1) In the case of synthesizing from polyamide acid, polyamide ester can be synthesized by esterifying polyamide acid obtained from tetracarboxylic dianhydride and diamine. [0073] Specifically, it can be achieved by combining polyamide acid and an esterifying agent in the presence of an organic solvent at -20°C to 150°C, preferably at 0°C to 50°C, for 30 minutes to 24 minutes. It is synthesized by reacting it in hours, preferably 1 hour to 4 hours. [0074] As the esterification agent, those that can be easily removed by purification are preferred, and examples include N,N-dimethylformamide dimethyl acetal and N,N-dimethylformamide Diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide Amine bis-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-toluene Triazene, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine hydrochloride, etc. The addition amount of the esterification agent is preferably 2 mol equivalent to 6 mol equivalent with respect to 1 mol of the repeating unit of polyamide acid. [0075] The solvent used in the above reaction is N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone as far as the solubility of the polymer is concerned. Preferably, these systems may be used singly or in combination of two or more. In terms of the concentration during synthesis, it is less likely to cause precipitation of the polymer and to easily obtain a high-molecular weight body, preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass. [0076] (2) In the case of synthesizing by the reaction of tetracarboxylic acid diester dichloride and diamine, the polyamide can be synthesized from tetracarboxylic acid diester dichloride and diamine. [0077] Specifically, the tetracarboxylic acid diester dichloride and diamine can be combined in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, to It is synthesized by reacting for 30 minutes to 24 hours, preferably 1 hour to 4 hours. [0078] As the aforementioned base system, pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used, but pyridine is preferred for the stable progress of the reaction. The addition amount of the base is preferably 2 times mol to 4 times mol relative to the tetracarboxylic acid diester dichloride in terms of an amount that can be easily removed and that a high-molecular-weight body can be easily obtained. [0079] The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in terms of the solubility of monomers and polymers. One or two or more types may be mixed and used. In terms of the polymer concentration during synthesis, it is not easy to cause the precipitation of the polymer, and it is easy to obtain a high-molecular weight body, preferably 1% to 30% by mass, and more preferably 5% to 20% by mass . In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the synthesis of polyamide esters is preferably dehydrated as much as possible, and it is better to prevent the mixing of foreign gases in a nitrogen environment. good. [0080] (3) In the case of synthesizing a polyamide ester from a tetracarboxylic acid diester and a diamine, the polyamide ester system can be synthesized by condensation polymerization of a tetracarboxylic acid diester and a diamine. [0081] Specifically, the tetracarboxylic acid diester and the diamine can be prepared by combining the tetracarboxylic acid diester and the diamine in the presence of a condensing agent, a base, and an organic solvent at 0°C to 150°C, preferably 0°C to 100°C, It is synthesized by reacting for 30 minutes to 24 hours, preferably 3 hours to 15 hours. [0082] As the aforementioned condensing agent, triphenyl phosphite, dicyclohexyl carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethyl morpholinium chloride, O-(benzotriazol-1-yl)-N,N,N ',N'-tetramethylurea tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylurea hexafluorophosphate, (2,3 -Dihydro-2-sulfanyl-3-benzo

Azolyl) phosphonic acid diphenyl ester and the like. The addition amount of the condensing agent is preferably 2 times to 3 times mol with respect to the tetracarboxylic acid diester. [0083] As the aforementioned base system, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 times mol to 4 times mol relative to the diamine component in terms of an amount that can be easily removed and that a high-molecular-weight body can be easily obtained. [0084] Furthermore, in the above reaction, by adding a Lewis acid as an additive, the reaction can proceed efficiently. As the Lewis acid system, lithium halides such as lithium chloride and lithium bromide are preferred. The addition amount of the Lewis acid is preferably 0 times mol to 1.0 times mol relative to the diamine component. [0085] Among the above three methods for synthesizing polyamides, since high-molecular-weight polyamides can be obtained, the synthesis method of (1) or (2) above is particularly preferred. [0086] The solution of the polyamide ester obtained in the above-mentioned manner is poured into the poor solvent while fully stirring, so that the polymer can be precipitated. After several times of precipitation and washing with a poor solvent, a purified polyamide powder can be obtained after drying at room temperature or by heating. The poor solvent is not particularly limited, and examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene. [0087] <Method for producing polyimide acid> The polyimide acid of the polyimide precursor used in the present invention can be synthesized by the method shown below. [0088] Specifically, tetracarboxylic dianhydride and diamine can be combined in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours , It is preferably 1 hour to 12 hours to make it react and synthesize. [0089] The organic solvent used in the above reaction is based on N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ- Butyrolactone is preferable, and these systems may be used alone or in combination of two or more kinds. The concentration of the polymer is less likely to cause precipitation of the polymer and is easy to obtain a high-molecular-weight body, preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass. [0090] The polyamide system obtained in the manner described above can be recovered by injecting the polymer into a poor solvent while fully stirring the reaction solution. In addition, after several times of precipitation and washing with a poor solvent, it is possible to obtain a purified polyamide acid powder by drying at room temperature or by heating. The poor solvent is not particularly limited, and examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene. [0091] <Method for producing polyimines> The polyimines used in the present invention can be produced by imidizing the aforementioned polyamide or polyamide. In the case of producing polyimide from polyamide, a polyamide obtained by adding an alkaline catalyst to the aforementioned polyamide solution or dissolving polyamide resin powder in an organic solvent The chemical imidization by adding an alkaline catalyst to the amino acid solution is easy. The chemical imidization is preferably because the imidization reaction is carried out at a relatively low temperature, and the molecular weight of the polymer is not easily reduced during the imidization process. [0092] The chemical imidization system can be carried out by stirring the polyamide to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, triethylamine is preferred because it has sufficient basicity necessary for the reaction to proceed. [0093] The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 hour to 100 hours. The amount of the alkaline catalyst is 0.5 mol times to 30 mol times, preferably 2 mol times to 20 mol times of the polyamide ester group. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst and the like will remain in the solution after the imidization reaction, it is preferable to recover the obtained imidization polymer by the following means, and redissolve it in an organic solvent to prepare the present invention Liquid crystal alignment agent. [0094] In the case of producing polyimide from polyamic acid, a chemical imide of catalyst is added to the solution of polyimide obtained by the reaction of a diamine component and tetracarboxylic dianhydride Turned into simplicity. The chemical imidization is preferable because the imidization reaction is carried out at a relatively low temperature, and the molecular weight of the polymer is not likely to decrease during the imidization process. [0095] The chemical imidization system can be carried out by stirring the polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferred because it has a moderate basicity required for the reaction to proceed. Moreover, as an acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic acid dianhydride, etc. are mentioned, Especially, since acetic anhydride is easy to purify after completion|finish of reaction when using acetic anhydride, it is preferable. [0096] The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time can be carried out from 1 hour to 100 hours. The amount of alkaline catalyst is 0.5 mol times to 30 mol times of the amide acid group, preferably 2 mol times to 20 mol times, and the amount of acid anhydride is 1 mol time of the amide acid group ~50 mole times, preferably 3 mole times to 30 mole times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. [0097] In the solution after the imidization reaction of polyamide or polyamide, since the added catalyst and the like will remain, it is preferable to recover the obtained imine by the following means The polymer is synthesized and re-dissolved in an organic solvent to prepare the liquid crystal alignment agent of the present invention. [0098] The polyimide solution obtained in the above-mentioned manner is poured into the poor solvent while being sufficiently stirred, so that the polymer can be precipitated. After several times of precipitation and washing with a poor solvent, it is dried at room temperature or by heating to obtain a purified polyamide ester powder. [0099] The aforementioned poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and the like. [0100] <Liquid crystal alignment agent> The liquid crystal alignment agent used in the present invention is in the form of a solution in which a polymer having a specific structure is dissolved in an organic solvent. The molecular weight of the polyimide precursor and polyimine described in the present invention is preferably 2,000 to 500,000 in terms of weight average molecular weight, more preferably 5,000 to 300,000, and more preferably 10,000 to 100,000. In addition, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and more preferably 5,000 to 50,000. [0101] The polymer concentration of the liquid crystal alignment agent used in the present invention can be appropriately changed according to the setting of the thickness of the coating film to be formed. For the point of forming a uniform and defect-free coating film, it is 1 weight % Or more is preferable, and in terms of storage stability of the solution, 10% by weight or less is preferable. [0102] The liquid crystal alignment agent of the present invention may also contain various additives such as a silane coupling agent or a crosslinking agent. The silane coupling agent is added for the purpose of improving the adhesion between the substrate coated with the liquid crystal alignment agent and the liquid crystal alignment film formed on the substrate. Silane coupling agents can be added to existing ones. [0103] If the addition amount of the silane coupling agent is too large, unreacted substances will adversely affect the alignment of the liquid crystal. %~5.0% by weight is preferable, and 0.1% by weight to 1.0% by weight is more preferable. When adding the above-mentioned silane coupling agent, in order to prevent the precipitation of the polymer, it is preferable to add the silane coupling agent before adding the aforementioned solvent for improving the uniformity of the coating film. [0104] Furthermore, in order to efficiently perform the imidization of the polyimide precursor during the firing of the coating film, an imidization accelerator may also be added to the liquid crystal alignment agent of the present invention. As the imidization accelerator system, existing ones can be used. [0105] When adding an imidization accelerator, since there is a possibility that the imidization may proceed due to heating, it is better to add it after diluting with a good solvent and a poor solvent. [0106] <Liquid crystal alignment film> The liquid crystal alignment film of the present invention is a film obtained by coating the above-mentioned liquid crystal alignment agent on a substrate, drying and firing. The substrate on which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate. Plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, etc. can be used to simplify the process. From a standpoint, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal has been formed. In addition, in the reflective liquid crystal display element, if only a single-sided substrate is used, opaque materials such as silicon wafers can also be used. In this case, materials such as aluminum that reflect light can also be used for the electrodes. [0107] As the coating method of the liquid crystal alignment agent of the present invention, spin coating method, printing method, etc. can be used, but as described above, the liquid crystal alignment agent of the present invention is particularly suitable for inkjet methods. When the liquid crystal alignment agent of the present invention is applied by the inkjet method to form a coating film (inkjet coating), the uniformity of the film thickness in the coating surface or the linearity of the coating periphery can be obtained. Excellent coating film. [0108] Any temperature and time can be selected for the drying and firing steps after applying the liquid crystal alignment agent of the present invention. Generally, in order to sufficiently remove the organic solvent contained, it is dried at 50°C to 120°C for 1 minute to 10 minutes, and then fired at 150°C to 300°C for 5 minutes to 120 minutes. The thickness of the coating film after firing is not particularly limited. If it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, it is 5 nm to 300 nm, preferably 10 nm to 200 nm. [0109] After the liquid crystal alignment treatment agent of the present invention is coated on a substrate and fired, the alignment treatment is performed by rubbing treatment or photo-alignment treatment, or it can be used as a liquid crystal alignment film without alignment treatment in vertical alignment applications. . [0110] <Liquid crystal display element> The liquid crystal display element of the present invention is obtained by using the liquid crystal alignment agent of the present invention to obtain a substrate with a liquid crystal alignment film from the liquid crystal alignment agent of the present invention. Thus as a liquid crystal display element. [0111] The method of manufacturing the liquid crystal cell is not particularly limited, but if an example is to be given, a pair of substrates on which the liquid crystal alignment film has been formed is usually placed with the liquid crystal alignment film surface as the inner side, and the sandwich is preferably 1 μm~ A method in which spacers of 30 μm, and preferably 2 μm to 10 μm are installed, and the surroundings are fixed with a sealant and liquid crystal is injected for sealing. There is no particular limitation on the method of enclosing the liquid crystal, and examples include a vacuum method in which liquid crystal is injected after decompression in the produced liquid crystal cell, and a drip method in which liquid crystal is dripped and then sealed. [Examples] [0112] Examples are given below to further specifically explain the present invention. However, the present invention should not be limited to these embodiments but should be interpreted. [0113] The abbreviations used in the examples and comparative examples and the methods for measuring each characteristic are as follows. 1,3DMCBDA: 1,3-dimethyl 1,2,3,4 cyclobutane tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutane tetracarboxylic dianhydride DA-1: as follows Diamine DA-2 of the formula DA-1: Diamine of the following formula DA-2 DA-3: Diamine of the following formula DA-3 [0114]

[0115] Boc in the above formula DA-2 and the above formula DA-3 represents a tert-butoxycarbonyl group. [0116] <Solvent> NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve GBL: γ-butyrolactone BCA: butyl cellosolve acetate PB: propylene glycol monobutyl ether DME: dipropylene glycol dimethyl Ether DEDG: diethylene glycol diethyl ether DAA: diacetone alcohol 4M4M2P: 4-methoxy-4-methyl-2-pentanone 4H2B: 4-hydroxy-2-butanone 2M2H: 2-methyl-2- Hexanol [0117] <Viscosity> In the synthesis example, the viscosity of the polymer solution is based on the E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.). The sample volume is 1.1 mL and the cone rotor TE-1 (1°34 ', R24), the measurement is carried out at a temperature of 25°C. [0118] <Molecular weight> In the synthesis example, the molecular weight of the polymer was measured with a GPC (normal temperature gel permeation chromatography) device, and the number average molecular weight was calculated as a polyethylene glycol and polyethylene oxide conversion value ( Hereinafter, it is also referred to as Mn) and the weight average molecular weight (hereinafter also referred to as Mw). GPC device: manufactured by Shodex Corporation (GPC-101) Column: manufactured by Shodex Corporation (KD803 and KD805 in series) Column temperature: 50°C Eluent: N,N-dimethylformamide (as an additive, lithium bromide-hydrate (LiBr･H ₂ O) is 30mmol/L, phosphoric anhydride crystal (o-phosphoric acid) is 30mmol/L, tetrahydrofuran (THF) is 10ml/L) Flow rate: 1.0ml/min. Standard sample for calibration line production: Tosoh TSK standard polyethylene oxide manufactured by the company (weight average molecular weight (Mw) approximately 900,000, 150,000, 100,000, 30,000), and polyethylene glycol manufactured by Polymer Laboratories (peak top molecular weight (Mp) approximately 12,000, 4,000, 1,000). In order to avoid overlapping of peaks, the measurement was performed by mixing two samples of four types of samples of 900,000, 100,000, 12,000, and 1,000, and three types of samples of 150,000, 30,000, and 4,000. <Synthesis Example> (Synthesis Example 1) In a 50 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 1.88 g (7.70 mmol) of DA-1 and 1.17 g (2.11 mmol) of DA-3 were measured. , DA-2 1.67g (4.20mmol), add 40.00g of NMP, and stir to dissolve it while feeding nitrogen. While stirring the diamine solution, 2.04 g (9.10 mmol) of 1,3DMCBDA was added and further stirred. After the viscosity became stable, 0.62 g (3.16 mmol) of CBDA was added, and NMP was added so that the solid content concentration became 15% by mass, and Stir at room temperature for 24 hours to obtain a solution of polyamide acid (PAA-1). The viscosity of the polyamide acid solution at 25°C was 212mPa･S. [0120] (Synthesis Example 2) In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 30 g of PAA-1 obtained in Synthesis Example 1 was measured, and NMP was added so that the solid content concentration became 8% by mass. And dilute. [0121] Next, 2.61 g (25.5 mmol) of acetic anhydride and 0.67 g (8.47 mmol) of pyridine were added and dissolved. Next, while stirring this solution, it heated to 55 degreeC, and it was made to react for 3 hours. The obtained polyamide acid-soluble polyimidic acid solution was poured into methanol of 3.5 times the same amount of the total solution while stirring, and re-precipitated. The re-precipitated powder system is filtered through natural filtration or suction filtration, and then 0.188l (5.86mmol) of methanol is washed in 2 times and dried to obtain white polyamide acid. -Soluble polyimide resin powder (PWD-1). The molecular weight of this resin powder was Mn=13,493 and Mw=27,207. [0122] The PWD-1 obtained above was dissolved in NMP to obtain a polyamide acid-soluble polyimide resin powder solution (SPI-1) with a solid content concentration of 12% by mass. (Example 1) In a 20 ml sample tube with a stir bar, 6.75 g of the polyamide acid solution (PAA-1) obtained in Synthesis Example 1 was measured, and 3 was diluted with NMP to 1.0% by mass. -0.81 g of glycidoxypropylmethyl diethoxysilane solution and 6.84 g of NMP. After that, 3.60 g of DAA was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal alignment agent (A-1). After storing the liquid crystal alignment agent A-1 at -20°C for 1 week, no solid matter was precipitated as a uniform solution. [0124] (Example 2 to Example 5, Comparative Example 1 to Comparative Example 6) In addition to using polyamide acid-soluble polyimide resin powder solution (SPI-1) instead of polyamide acid (PAA-1) ), or use the solvent in the following table instead of DAA as the solvent, and perform the same operation as in Example 1 to obtain liquid crystal alignment agents (A-2)~(A-5), (B-1)~ (B-6). After storing all the liquid crystal alignment agents obtained as described above at -20°C for one week, precipitation of solid matter was not observed as a uniform solution. The results are shown in Table 1 below. [0125] [Table 1]

[0126] In order to evaluate the electrical characteristics of the liquid crystal cell, a substrate with electrodes is first prepared. The substrate is a glass substrate with a size of 30mm×40mm and a thickness of 1.1mm. An ITO electrode with a film thickness of 35 nm was formed on the substrate, and the electrode had a stripe pattern of 40 mm in length and 10 mm in width. [0127] Next, after filtering the liquid crystal alignment agent using a 1.0 μm filter, it was spin-coated on the prepared substrate with the aforementioned electrode. After drying on a hot plate at 50°C for 5 minutes, it was fired in an IR oven at 230°C for 20 minutes to form a coating film with a thickness of 100 nm, thereby obtaining a substrate with a liquid crystal alignment film. After rubbing the liquid crystal alignment film with a rayon cloth (roll diameter: 120mm, roll rotation number: 1000rpm, moving speed: 20mm/sec, pressing length: 0.4mm), it was washed by ultrasonic irradiation in pure water for 1 minute. After removing the water droplets by blowing air, it was dried at 80° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film. Prepare two substrates with the liquid crystal alignment film, spread a 4μm spacer on the surface of one of the liquid crystal alignment films, and then print the sealant from the top of the liquid crystal alignment film. The rubbing direction is reversed and the film surfaces face each other. After the other substrate is pasted, the sealant is hardened to produce an empty cell. Liquid crystal ML-7026-100 (manufactured by Merck Japan) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. After that, the obtained liquid crystal cell was heated at 120° C. for 60 minutes, and then cooled to room temperature. After observation of the cell, the alignment was good. [0128] <Measurement of voltage holding ratio> (Example 6) A voltage of 1V was applied to the above-mentioned liquid crystal cell at a temperature of 60° C. for 60 μs, and the voltage after 50 ms was measured, and the voltage holding ratio was determined as the voltage holding ratio. To perform calculations. [0129] As a result, the voltage retention rate of the alignment film formed by the alignment agent A-1 at 60° C. was 96.7%. [0130] (Example 7 to Example 10, Comparative Example 7 to Comparative Example 12) For the alignment agent (A-2) to the alignment agent ( A-5) and the aligning agent (B-1) to the aligning agent (B-6) were also made into liquid crystal cells by the same method, and the voltage holding ratio was measured by the measurement method described in Example 6. The results of each are shown in Table 2 below. [Table 2]

[Industrial Applicability] [0132] It can be widely used in TN elements, STN elements, TFT liquid crystal elements, and further used in vertical alignment type liquid crystal display elements.

Claims (8)

A liquid crystal alignment agent characterized by containing at least one polymer selected from the group consisting of polyimine and polyimide precursors, and a solvent containing the following groups (A) and (B) Organic solvents, group (A): at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone; group (B): select At least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone, and 2-methyl-2-hexanol. The liquid crystal alignment agent of claim 1, wherein the solvent of the aforementioned group (A) contains at least one selected from the group consisting of N-methyl-2-pyrrolidone and γ-butyrolactone. Such as the liquid crystal alignment agent of claim 1 or claim 2, wherein the solvent of the aforementioned group (A) relative to the total solvent amount is 50% by weight to 95% by weight. Such as the liquid crystal alignment agent of claim 1 or claim 2, wherein the solvent of the aforementioned group (B) relative to the total solvent amount is 5 wt% to 50 wt%. Such as the liquid crystal alignment agent of claim 1 or claim 2, which contains 1% to 5% by mass of the aforementioned polymer. Such as the liquid crystal alignment agent of claim 1 or claim 2, which contains 95 quality The amount of the aforementioned solvent is %~99% by mass. A liquid crystal alignment film characterized by being obtained from the liquid crystal alignment agent of any one of claims 1 to 6. A liquid crystal display element characterized by being provided with the liquid crystal alignment film of claim 7.