JPH06212156A - Method for purifying liquid crystal composition - Google Patents
Method for purifying liquid crystal compositionInfo
- Publication number
- JPH06212156A JPH06212156A JP752593A JP752593A JPH06212156A JP H06212156 A JPH06212156 A JP H06212156A JP 752593 A JP752593 A JP 752593A JP 752593 A JP752593 A JP 752593A JP H06212156 A JPH06212156 A JP H06212156A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- crystal composition
- polyimide resin
- resin powder
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Liquid Crystal Substances (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、液晶組成物の精製方
法に関する。TECHNICAL FIELD The present invention relates to a method for purifying a liquid crystal composition.
【０００２】[0002]
【従来の技術】従来の液晶組成物の精製方法は、液晶組
成物にアルミナ、シリカゲル又はモレキュラシーブスの
粉末を混合処理してイオン性不純物の除去をして行なわ
れている。2. Description of the Related Art A conventional method for purifying a liquid crystal composition is carried out by mixing the liquid crystal composition with alumina, silica gel or molecular sieves powder to remove ionic impurities.
【０００３】[0003]
【発明が解決しようとする課題】従来の液晶組成物の精
製方法は、用いる粉末が吸着性が強すぎるため、液晶成
分の一部に対しても吸着性を示すため液晶組成物の組成
が変化し、ネマチック−アイソトロピック相転移温度が
上昇するという問題がある。In the conventional method for purifying a liquid crystal composition, since the powder used has too strong an adsorptivity, the composition of the liquid crystal composition changes because it exhibits an adsorptivity even for a part of the liquid crystal component. However, there is a problem that the nematic-isotropic phase transition temperature rises.
【０００４】この発明は、上記問題を解決するためにな
されたものであって、液晶組成物の組成変化がなく、ネ
マチック−アイソトロピック相転移温度が上昇せず、イ
オン性不純物を除去して比抵抗を向上することのできる
液晶組成物の精製方法を提供しようとするものである。The present invention has been made in order to solve the above-mentioned problems, in which the composition of the liquid crystal composition does not change, the nematic-isotropic phase transition temperature does not rise, and the ionic impurities are removed to obtain a relative ratio. An object of the present invention is to provide a method for purifying a liquid crystal composition that can improve resistance.
【０００５】[0005]
【課題を解決するための手段】この発明によれば、液晶
組成物にポリイミド樹脂粉末を混合処理してイオン性不
純物の除去をすることを特徴とする液晶組成物の精製方
法が提供される。上記液晶組成物は、通常液晶表示素子
等に用いられる公知の液晶組成物を用いることができ、
精製前には通常液晶表示素子作製プロセスの複数の工程
でイオン性不純物が混入し、１×１０12〜３×１０12Ω
・cmの比抵抗を呈する。According to the present invention, there is provided a method for purifying a liquid crystal composition, which comprises mixing a liquid crystal composition with a polyimide resin powder to remove ionic impurities. As the liquid crystal composition, a known liquid crystal composition usually used for liquid crystal display devices and the like can be used,
Prior to purification, ionic impurities are usually mixed in in a plurality of steps of the liquid crystal display element manufacturing process, and thus 1 × 10 12 to 3 × 10 12 Ω
・ It exhibits a specific resistance of cm.
【０００６】上記ポリイミド樹脂粉末は、液晶組成物を
処理するためのものであって、組成変化を起すことな
く、液晶組成物中のイオン性不純物を除去するものであ
って、公知のポリイミド樹脂の粉末を用いることができ
る。このポリイミド樹脂は、液晶表示素子に対して広く
配向膜材料として用いられるポリイミドの粉末等を好適
に用いることができる。The above-mentioned polyimide resin powder is for treating a liquid crystal composition and removes ionic impurities in the liquid crystal composition without causing a composition change. Powders can be used. As the polyimide resin, polyimide powder widely used as an alignment film material for liquid crystal display elements can be preferably used.
【０００７】この粒径は、通常５〜５０μｍである。こ
の表面は、多孔性にしたり凹凸を形成し吸着面積を増し
てもよいがしなくてもよい。液晶組成物とポリイミド樹
脂粉末との混合は、液晶組成物を液晶又は液体の状態に
なるように適宜温度を制御して行うことができる。The particle size is usually 5 to 50 μm. This surface may or may not be made porous or uneven to increase the adsorption area. The liquid crystal composition and the polyimide resin powder can be mixed by appropriately controlling the temperature so that the liquid crystal composition is in a liquid crystal or liquid state.
【０００８】混合比は、液晶組成物に対するポリイミド
樹脂粉末の割合が、通常１〜１０重量％好ましくは２〜
５重量％である。１重量％未満では、液晶組成物中のイ
オン性不純物を十分に除去することができないので好ま
しくない。１０重量％超ではポリイミド樹脂粉末量が液
晶組成物に対し、過剰であり必要はない。The mixing ratio is such that the ratio of the polyimide resin powder to the liquid crystal composition is usually 1 to 10% by weight, preferably 2 to
It is 5% by weight. If it is less than 1% by weight, ionic impurities in the liquid crystal composition cannot be sufficiently removed, which is not preferable. If it exceeds 10% by weight, the amount of the polyimide resin powder is excessive with respect to the liquid crystal composition and is not necessary.
【０００９】混合時間は、液晶組成物中のイオン性不純
物がポリイミド樹脂粉末に吸着するのに要する時間であ
ればよく、通常約１時間であり必要によって更に短縮す
ることができる。所定時間混合した後、ポリイミド樹脂
粉末と液晶組成物とを分離する。この分離は、例えば混
合物の静置によってポリイミド樹脂粉末を沈澱させ上澄
液を、例えば細管を通して吸引して分離し、更に遠心分
離処理し、再び細管を通して上澄み液を吸引して精製し
た液晶組成物を取出して行うことができる。The mixing time may be any time required for the ionic impurities in the liquid crystal composition to be adsorbed on the polyimide resin powder, and is usually about 1 hour, and can be further shortened if necessary. After mixing for a predetermined time, the polyimide resin powder and the liquid crystal composition are separated. In this separation, for example, the liquid crystal composition obtained by precipitating the polyimide resin powder by allowing the mixture to stand and then separating the supernatant liquid by, for example, suctioning through a narrow tube, further centrifuging, and again sucking the supernatant liquid through the narrow tube to obtain a purified liquid composition You can take it out and do it.
【００１０】遠心分離処理の代りに、例えば濾過法によ
っても行うことができる。精製した液晶組成物は、精製
前と液晶成分の組成変化を起すことなく、イオン性不純
物が低減される。Instead of the centrifugal separation treatment, for example, a filtration method can also be used. In the purified liquid crystal composition, ionic impurities are reduced without causing the composition change of the liquid crystal component before purification.
【００１１】この液晶組成物は、保存すると経時的に吸
湿などによって再び比抵抗が低下するので、直ちに液晶
セル等に封入して用いるのが好ましい。保存は、ポリイ
ミド樹脂粉末と混合した状態で行うと比抵抗の低下がな
いので好ましい。Since the specific resistance of this liquid crystal composition decreases again when it is stored due to moisture absorption or the like, it is preferable to immediately use it by enclosing it in a liquid crystal cell or the like. The storage is preferably carried out in a state of being mixed with the polyimide resin powder because the specific resistance does not decrease.
【００１２】[0012]
【作用】ポリイミド樹脂粉末が、その極性基によって吸
着性を呈し、その強さが強すぎず適度であるため液晶組
成物を構成する成分を吸着することなく、液晶組成物中
のイオン性不純物を吸着して除去する。[Function] The polyimide resin powder exhibits an adsorptive property due to its polar group, and its strength is not too strong and moderate, so that it does not adsorb the components constituting the liquid crystal composition and removes ionic impurities in the liquid crystal composition. Adsorb and remove.
【００１３】[0013]
【実施例】以下本発明の実施例をグラフ図を用いて説明
する。実施例に於いて、使用した材料は、液晶組成物が
日立化成（株）ＦＨ−２０００であり、ポリイミド樹脂
粉末が粒径５μｍから５０μｍで平均粒径７．２μｍで
あって、液晶配向膜形成用のポリイミド樹脂を粉末化し
たものである。EXAMPLES Examples of the present invention will be described below with reference to graphs. In the examples, the materials used were a liquid crystal composition of FH-2000 manufactured by Hitachi Chemical Co., Ltd., a polyimide resin powder having a particle size of 5 μm to 50 μm and an average particle size of 7.2 μm. It is a powdered polyimide resin for use.
【００１４】イオン性不純物が混入していると考えられ
比抵抗が下がっている液晶組成物の中にポリイミド樹脂
粉末を混ぜ、１０〜２０分間攪拌した後その上澄み液を
注射器で取り出し、遠心分離機にかけ、更にその上澄み
を注射器で取出すという作業を行い液晶組成物とポリイ
ミド樹脂を分離した。Polyimide resin powder is mixed in a liquid crystal composition which is considered to contain ionic impurities and has a lowered specific resistance, and the mixture is stirred for 10 to 20 minutes and then the supernatant is taken out with a syringe and centrifuged. Then, the supernatant was taken out with a syringe to separate the liquid crystal composition and the polyimide resin.
【００１５】ポリイミド樹脂粉末の対液晶組成物量を
１．２重量％〜１０重量％まで変えて液晶組成物に混合
し、時間経過に対する液晶組成物の比抵抗と相転移温度
を測定しそれらの関係を図１，図２及び図３に示す。The amount of the polyimide resin powder with respect to the liquid crystal composition was changed from 1.2% by weight to 10% by weight and mixed with the liquid crystal composition, and the specific resistance and the phase transition temperature of the liquid crystal composition with respect to the passage of time were measured and the relationship between them was measured. Is shown in FIGS. 1, 2 and 3.
【００１６】図１から、約２重量％以上のポリイミド樹
脂粉末を液晶組成物に混合した後ポリイミド樹脂粉末を
除去することにより液晶組成物の比抵抗に顕著な向上が
見られた。液晶組成物中のイオン性不純物がポリイミド
粉末に吸着して除去されたと考えられる。図２から、混
合時間は１〜２４時間でいずれも同様の効果がみられ１
時間で十分であると考えられる。図３から、相転移温度
（ＴNI、ネマチック相とアイソトロピック相）の上昇が
ないことから液晶組成への影響もないことが理解され
る。From FIG. 1, it was found that the specific resistance of the liquid crystal composition was remarkably improved by mixing the liquid crystal composition with about 2% by weight or more of the polyimide resin powder and then removing the polyimide resin powder. It is considered that the ionic impurities in the liquid crystal composition were adsorbed by the polyimide powder and removed. From FIG. 2, the mixing time was 1 to 24 hours, and the same effect was observed in all cases.
Time is considered sufficient. From FIG. 3, it is understood that there is no increase in the phase transition temperature (T NI , nematic phase and isotropic phase), and therefore there is no influence on the liquid crystal composition.
【００１７】次に、ポリイミド粉末で処理した液晶組成
物の中に、再びポリイミド粉末を液晶に対して１０重量
％添加したものと、比較のためポリイミド粉末を添加し
ないものとを４ヵ月間保存し、液晶の比抵抗の経時的な
変化を測定した。この結果、図４に示すようにポリイミ
ド粉末を添加しないものは、経時的に比抵抗の低下が認
められたが、添加したものは比抵抗の低下は認められず
安定した比抵抗を示した。Next, in the liquid crystal composition treated with the polyimide powder, one in which 10% by weight of the polyimide powder was again added to the liquid crystal and one in which the polyimide powder was not added for comparison were stored for 4 months. The change in resistivity of the liquid crystal with time was measured. As a result, as shown in FIG. 4, the one in which the polyimide powder was not added showed a decrease in the specific resistance with time, but the one in which the polyimide powder was added did not show the decrease in the specific resistance and showed a stable specific resistance.
【００１８】[0018]
【発明の効果】この発明によれば、液晶組成物の組成変
化を起すことなく、液晶組成物中のイオン性不純物を除
去できる液晶組成物の精製方法を提供することができ
る。この方法を用いることにより、比抵抗の高い液晶組
成物を提供することができる。According to the present invention, it is possible to provide a method for purifying a liquid crystal composition capable of removing ionic impurities in the liquid crystal composition without causing a composition change of the liquid crystal composition. By using this method, a liquid crystal composition having a high specific resistance can be provided.
【図１】この発明の実施例で行った液晶組成物の精製に
おけるポリイミド樹脂粉末量と精製した液晶組成物の比
抵抗の関係グラフ図である。FIG. 1 is a graph showing the relationship between the amount of polyimide resin powder and the specific resistance of the purified liquid crystal composition in the purification of the liquid crystal composition carried out in an example of the present invention.
【図２】この発明の実施例で行った液晶組成物の精製に
おける混合時間と比抵抗の関係グラフ図である。FIG. 2 is a graph showing the relationship between the mixing time and the specific resistance in the purification of the liquid crystal composition performed in the example of the present invention.
【図３】この発明の実施例で行った液晶組成物の精製に
おける混合時間と相転移温度の関係グラフ図である。FIG. 3 is a graph showing a relationship between a mixing time and a phase transition temperature in refining a liquid crystal composition in an example of the present invention.
【図４】この発明の実施例で行った液晶組成物の精製に
おける保存期間と比抵抗の関係グラフ図である。FIG. 4 is a graph showing the relationship between the storage period and the specific resistance in the purification of the liquid crystal composition performed in the example of the present invention.
Claims (1)
処理してイオン性不純物を除去することを特徴とする液
晶組成物の精製方法。1. A method for purifying a liquid crystal composition, which comprises mixing a liquid crystal composition with a polyimide resin powder to remove ionic impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5007525A JP3012419B2 (en) | 1993-01-20 | 1993-01-20 | Liquid crystal composition purification method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5007525A JP3012419B2 (en) | 1993-01-20 | 1993-01-20 | Liquid crystal composition purification method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06212156A true JPH06212156A (en) | 1994-08-02 |
| JP3012419B2 JP3012419B2 (en) | 2000-02-21 |
Family
ID=11668200
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5007525A Expired - Lifetime JP3012419B2 (en) | 1993-01-20 | 1993-01-20 | Liquid crystal composition purification method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3012419B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015098702A1 (en) * | 2013-12-25 | 2015-07-02 | Dic株式会社 | Compound containing mesogenic group, and mixture, composition, and optically anisotropic body using said compound |
-
1993
- 1993-01-20 JP JP5007525A patent/JP3012419B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015098702A1 (en) * | 2013-12-25 | 2015-07-02 | Dic株式会社 | Compound containing mesogenic group, and mixture, composition, and optically anisotropic body using said compound |
| JPWO2015098702A1 (en) * | 2013-12-25 | 2017-03-23 | Dic株式会社 | Compound containing mesogenic group, mixture using the same, composition, and optical anisotropic body |
| US10473820B2 (en) | 2013-12-25 | 2019-11-12 | Dic Corporation | Compound containing mesogenic group, and mixture, composition, and optically anisotropic body using said compound |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3012419B2 (en) | 2000-02-21 |
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