JP2005052742A - Processing method for liquid crystal washing liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently treating a liquid crystal washing liquid after washing the liquid crystal at a low cost without generating a problem of environment. <P>SOLUTION: The processing method for a liquid crystal washing liquid includes a first step where by using an extract liquid for dissolving the liquid crystal and water at a first temperature and making the liquid crystal and water to the different state where they are dissolved and not dissolved at a second temperature different from the first temperature, the liquid crystal washing liquid is dissolved in the extract liquid at the first temperature to prepare a solution 3; and a second step where the temperature of the solution 3 is varied from the first temperature to the second temperature and the liquid crystal and water are separated from the solution in the state where any one of the liquid crystal and water is dissolved in the extract liquid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for treating a liquid crystal cleaning liquid after cleaning an article to which liquid crystal is adhered.

  As a general manufacturing method of a liquid crystal panel, for example, there is a technique called vacuum injection. In this vacuum injection, a transparent substrate, such as glass, to which an alignment film or the like is attached is sandwiched between a substrate and a predetermined gap to obtain a space called a cell. Then, the injection port provided at one end of the panel is immersed in the liquid crystal while maintaining the vacuum state in the cell. At this time, liquid crystal is injected into the vacuum cell by opening the periphery of the panel to atmospheric pressure.

In the liquid crystal panel obtained by such a manufacturing method, when the liquid crystal is injected into the cell, one end of the liquid crystal panel in which the injection port is arranged is immersed in the liquid crystal, so that the liquid crystal adheres to a part of the substrate and the sealing material. To do. In order to remove the liquid crystal adhering to the substrate or the like, the liquid crystal panel is immersed in a cleaning liquid containing a surfactant, finally washed with water, and then dried (see, for example, Patent Document 1). . In addition, in the general manufacturing process of liquid crystal products, unnecessary liquid crystal adhering to parts and manufacturing apparatuses may be washed. In addition, in order to increase the cleaning power, a cleaning method using ultrasonic waves has been developed.
JP-A-8-179293

However, in the conventional liquid crystal cleaning method, after the liquid crystal is cleaned, the liquid crystal cleaning liquid containing the liquid crystal is incinerated as industrial waste. Most of the liquid crystal cleaning liquid is water, and the incineration process is inefficient and expensive. In recent years, environmental concerns about the outflow of liquid crystals have also been shown.
Therefore, an object of the present invention is to obtain a method for treating a liquid crystal cleaning liquid efficiently, at low cost and without causing environmental problems.

In order to solve such a problem, the present invention is a method of treating a liquid crystal cleaning liquid containing at least the liquid crystal and water after cleaning an article to which liquid crystal is adhered,
While the liquid crystal and the water are both dissolved at the first temperature, the liquid crystal and the water are dissolved and not dissolved in the second temperature different from the first temperature. Using a first step of dissolving the liquid crystal cleaning solution in the extract at the first temperature to create a solution;
The temperature of the solution is changed from the first temperature to the second temperature, and either the liquid crystal or the water is dissolved in the extract, and the liquid crystal and the water are changed from the solution. And a second step of separating.

  The liquid crystal and the water are dissolved together at the first temperature, while the second liquid different from the first temperature is used as an extract having different states in which the liquid crystal and the water are dissolved or not dissolved. Thus, the liquid crystal and water can be separated. Since the liquid crystal separated from the liquid crystal cleaning liquid contains a high concentration of liquid crystal when incinerated as waste, it is more efficient than the case where the liquid crystal cleaning liquid is similarly processed. In addition, since the water separated from the liquid crystal cleaning liquid does not contain liquid crystal, it can be drained.

  In the method for treating a liquid crystal cleaning liquid, when the liquid crystal cleaning liquid further contains a surfactant, the surfactant is used as a liquid crystal component together with the liquid crystal after the first step and the second step. It is preferable to separate from water. When the liquid crystal cleaning liquid contains a surfactant, the liquid crystal and the surfactant have properties closer to each other than water. Therefore, if the extract liquid mentioned above is used, the liquid crystal component containing the liquid crystal and the surfactant and water can be separated. Since the liquid crystal component contains a liquid crystal having a higher concentration than the liquid crystal cleaning liquid, the liquid crystal component is efficient when incinerated. Further, as described above, the water separated from the liquid crystal cleaning liquid can be drained.

  Further, in the method for treating a liquid crystal cleaning liquid, it is desirable to add a deactivator for deactivating the surfactant to the liquid crystal component to separate the liquid crystal from the surfactant. By separating the liquid crystal and the surfactant-containing liquid, a higher concentration liquid crystal can be obtained, which can be more efficiently processed by a method such as incineration. In addition, the surfactant-containing liquid containing the surfactant separated from the liquid crystal component can be subjected to wastewater treatment after decomposing the surfactant, and since this wastewater does not contain liquid crystal, it is excellent in terms of environment. ing.

Furthermore, in such a method for treating a liquid crystal cleaning liquid, it is desirable that the liquid crystal separated from water or the surfactant after the second step is separated for each liquid crystal component. By separating each liquid crystal component, each component can be reused as a liquid crystal material, and waste can be reduced and the cost of the liquid crystal material can be reduced.
Furthermore, in this liquid crystal cleaning liquid treatment method, the liquid crystal separated from the liquid crystal cleaning liquid or the residue after separation for each liquid crystal component may be incinerated. The separated liquid crystal has an extremely high concentration as compared with the liquid crystal in the liquid crystal cleaning liquid, and incineration of the liquid crystal can be performed at a relatively low cost. Moreover, the said residue is easy to process similarly.

  Furthermore, in the method for treating a liquid crystal cleaning liquid, it is desirable to remove impurities in the extraction liquid in which either the liquid crystal or the water obtained in the second step is dissolved. By removing impurities, an extract with higher purity can be obtained, and this can be reused as a material for the extract used in the first step. Moreover, the water containing impurities from which the extract has been removed can usually be treated as waste water.

Hereinafter, although embodiment of this invention is described, this invention is not limited to the following embodiment.
According to the method for treating a liquid crystal cleaning liquid of the present invention, in the first step, a solution obtained by dissolving liquid crystal and water in an extract is obtained, and the solution is subjected to water or water at a second temperature different from the first temperature. It is characterized in that the liquid crystal and water can be separated under the condition that any one of the liquid crystals is dissolved in the extract.

  The extract dissolves both the liquid crystal and the water at a first temperature, while the liquid crystal and the water are different from each other in a second temperature different from the first temperature. It presents. Examples of substances having such properties include polyhydric alcohol derivatives (superior concept of glycol ether). Among these, polyhydric alcohol-derived ethers are preferable because the solubility in water greatly changes depending on the temperature difference, and examples include glycol ethers, ethylene glycol ethers, propylene glycol ethers, and the like. These glycol ethers can use what is marketed, for example, Sunclean XL-1 (made by Sanwa Oil Chemical Co., Ltd.) etc. are mentioned. The extract preferably contains 10 to 40% by mass of the glycol ether. If it deviates from this range, problems such as deterioration of the solubility of the liquid crystal and separation of the water-soluble component (electrolyte impurities) occur.

Hereinafter, the present invention will be described with reference to the drawings by exemplifying a case where liquid crystal that is unnecessarily attached to a liquid crystal panel manufactured by a vacuum injection method is washed.
FIG. 1 is a schematic flowchart showing an example of an embodiment of the present invention. The liquid crystal panel 1 is filled with liquid crystal in a cell by a method such as vacuum injection, and the injection port is sealed, and then usually immersed in a cleaning solution 2 (a, b, c...) In a multistage manner, and finally washed with water. As a result, the operation of gradually cleaning the liquid crystal adhering to the liquid crystal panel 1 is performed.

  The liquid crystal cleaning liquid contains at least water and liquid crystal to be cleaned after cleaning the article to which the liquid crystal is adhered. As shown in FIG. 1, when the liquid crystal panel 1 is cleaned in multiple stages, the liquid crystal is sequentially immersed in a first cleaning liquid 2a, a second cleaning liquid 2b, a third cleaning liquid 2c,. That is, in the liquid crystal cleaning liquid in which the liquid crystal is immersed in the first cleaning liquid 2a, the concentration of the liquid crystal becomes the highest, and the liquid crystal having a higher concentration can be separated by processing this by the method described later.

The liquid crystal component contained in the liquid crystal cleaning liquid is preferably 5% by mass or less. This is because if it exceeds 5% by mass, cleaning failure occurs due to re-contamination of the liquid crystal.
The liquid crystal is not particularly limited as long as it is a liquid crystal compound capable of forming a liquid crystal phase, and the number and type of chemical substances forming the liquid crystal compound are not particularly limited.

  Further, the liquid crystal cleaning liquid may contain a surfactant. The surfactant is one or more surfactants selected from nonionic surfactants and anionic surfactants, and examples thereof include polyoxyethylene alkyl ethers. Examples of commercially available products include Sunwash RE (manufactured by Lion Corporation) and Sunwash LH-8000 (manufactured by Lion Corporation).

  The liquid crystal cleaning liquid preferably contains 20 to 60% by mass of these surfactants. This is because if it is less than 20%, a sufficient liquid crystal cleaning effect cannot be obtained, and if it exceeds 60%, problems such as poor cleaning due to high concentration and poor rinsing (residual failure) occur. Furthermore, the liquid crystal cleaning liquid may contain the liquid crystal, water, and other components of the surfactant as long as they do not interfere with the cleaning effect of the liquid crystal. Further, in order to more efficiently clean the liquid crystal attached to the liquid crystal panel 1, a process such as propagation of ultrasonic waves to the liquid crystal cleaning liquid may be performed while the liquid crystal panel 1 is immersed.

In the first step of the present embodiment, the liquid crystal cleaning liquid is dissolved in the extraction liquid at the first temperature under the condition that the liquid crystal and the water are dissolved, thereby forming a solution 3. Further, the liquid crystal cleaning liquid further contains a surfactant, and the surfactant is also dissolved in the extract.
When forming the solution 3, the reaction temperature is preferably 50 to 70 ° C, for example, 60 ° C. The reaction time is preferably 5 to 15 minutes. When the reaction temperature deviates from this range, there is a problem that the solution does not become a uniform solution or the solution is volatilized or deteriorates due to heating. In addition, if the reaction time is too long, there arises a problem that the apparatus needs to be enlarged in order to ensure the process capability with respect to an increase in cycle time and an increase in processing time. Furthermore, it is preferable to mix the solution 3 so that the liquid crystal cleaning liquid and the extract liquid are 30 to 70% by mass and 70 to 30% by mass, respectively. The solution 3 may be stirred as appropriate.

Next, the temperature of the solution 3 is changed to a second temperature different from the first temperature, and the process proceeds to the second step. In the second step, the liquid crystal and water are separated from the solution 3 under a condition in which either the liquid crystal or the water is dissolved in the extract. The surfactant is separated from water as a liquid crystal component together with the liquid crystal. As preferable conditions, the reaction temperature is 20 to 50 ° C., for example, 40 ° C. The reaction time is 10 to 60 minutes. Beyond these ranges, separation is insufficient.
Since the liquid crystal component 4a is formed as a supernatant in the state 4b in which water is dissolved in the extract, the supernatant 4a can be separated by a method such as an oil / water separation method or a stationary separation method.

Hereinafter, a more preferable processing method for the liquid crystal content will be described with reference to FIG.
A deactivator for deactivating the surfactant is added to the liquid crystal component containing the liquid crystal and the surfactant. As the deactivator, a solution in which an inorganic salt such as calcium chloride or sodium chloride is dissolved in water as a solvent, preferably 1 to 20% by mass can be used. When such a quencher is added to the liquid crystal component, the reaction temperature is preferably 20 to 40 ° C., and the reaction time is preferably 5 to 30 minutes.

  By adding a quencher to the liquid crystal component, a liquid crystal is formed as the supernatant 5a. The supernatant 5a can be separated from the surfactant-containing liquid 5b containing a surfactant by a method such as an oil / water separation method or a stationary separation method. The liquid crystal thus separated contains a liquid crystal having a higher concentration than that of the liquid crystal component. When this is incinerated, it is more efficient than a case where a low concentration liquid crystal is processed in the same manner.

In addition, the liquid crystal can be further separated into each liquid crystal component by using a technique such as a multistage distillation method or a multistage solvent extraction. After being separated into each liquid crystal component, it can be reused as a raw material for the liquid crystal panel, and waste can be reduced and the cost of the liquid crystal material can be reduced. The residue after separation for each liquid crystal component is incinerated.
Since the surfactant is deactivated, the surfactant-containing liquid 5b can be subjected to wastewater treatment. Since this wastewater does not contain liquid crystal, it is environmentally friendly.

  In the second step described above, the treatment of the extraction solution 4b generated when the liquid crystal component 4a is separated in a state where water is dissolved in the extraction liquid is preferably performed as follows. The extraction solution 4b contains the water contained in the extraction liquid and the cleaning liquid 2. From this extraction solution 4b, ionic impurities are removed by a method such as distillation purification. The extracted solution after removing the impurities can be further reused as a raw material in the first step, and the liquid crystal cleaning liquid can be processed more efficiently.

As described above, the present invention has been described in detail by exemplifying the case where a liquid crystal panel is manufactured by a vacuum injection method and unnecessary liquid crystal is cleaned. However, the processing method of the liquid crystal cleaning liquid of the present invention is not limited to this. Absent. For example, the present invention can be applied to cleaning liquid crystals in the process of manufacturing a liquid crystal panel in general, and collecting and processing used liquid crystal products.
The present invention can also be applied when the liquid crystal cleaning liquid does not contain a surfactant. Furthermore, in the first step, water may be formed as a supernatant with the liquid crystal component dissolved in the extract.

  INDUSTRIAL APPLICABILITY The present invention can be applied when processing a liquid crystal cleaning liquid after cleaning a liquid crystal in a process of manufacturing various products using a liquid crystal panel such as a mobile phone, a notebook computer, and a liquid crystal television. Further, the present invention can be applied to the case where the liquid crystal is washed when these liquid crystal products are collected and processed.

It is a schematic flowchart which shows an example of embodiment of this invention. It is a schematic flowchart which shows an example of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel, 2a, 2b, 2c Cleaning liquid, 3 Solution, 4a Liquid crystal component, 4b Extraction solution, 5a Liquid crystal, 5b Surfactant containing liquid.

Claims (6)

A method of treating a liquid crystal cleaning liquid containing at least the liquid crystal and water after cleaning an article to which liquid crystal is adhered,
While the liquid crystal and the water are both dissolved at the first temperature, the liquid crystal and the water are dissolved and not dissolved in the second temperature different from the first temperature. Using a first step of dissolving the liquid crystal cleaning solution in the extract at the first temperature to create a solution;
The temperature of the solution is changed from the first temperature to the second temperature, and either the liquid crystal or the water is dissolved in the extract, and the liquid crystal and the water are changed from the solution. And a second step of separating the liquid crystal cleaning liquid.   The liquid crystal cleaning liquid further contains a surfactant, and after passing through the first step and the second step, the surfactant is separated from the water as a liquid crystal component together with the liquid crystal. Item 2. A method for treating a liquid crystal cleaning liquid according to Item 1.   3. The method for treating a liquid crystal cleaning liquid according to claim 2, wherein a deactivator for deactivating the surfactant is added to the liquid crystal component to separate the liquid crystal and the surfactant.   4. The method for treating a liquid crystal cleaning liquid according to claim 1, wherein the liquid crystal separated from the water or the surfactant after the second step is separated for each liquid crystal component.   The method for treating a liquid crystal cleaning liquid according to any one of claims 1 to 4, wherein the liquid crystal separated from the liquid crystal cleaning liquid or the residue after being separated for each liquid crystal component is subjected to incineration treatment. 6. The liquid crystal cleaning liquid according to claim 1, wherein impurities in the extraction liquid in which one of the liquid crystal and the water obtained in the second step is dissolved are removed. Processing method.

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