JP2005224715A - Treating method of waste liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the simple treating method of waste liquid crystal panels in a short period of time while recovering liquid crystal without incinerating the waste liquid crystal panels. <P>SOLUTION: This treating method of waste liquid crystal panels comprises: a polarizing plate treating process for dissolving the polarizing plate of the waste liquid crystal panels with a solvent having solubility to the plate to remove or harden it; a panel crushing process for crushing the waste liquid crystal panels subjected to the polarizing plate treatment; and a liquid crystal extraction process for extracting the liquid crystal from the crushed waste liquid crystal panels. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for treating a waste liquid crystal panel, and more particularly, to a method for treating a waste liquid crystal panel in which the waste liquid crystal panel is easily treated in a short time while collecting liquid crystal.

  In recent years, one of the approaches to environmental problems is so-called recycling. By recycling, products manufactured and sold by companies are collected and dismantled, parts, materials, etc. are extracted and parts, materials, etc. are reused, so that the amount of waste can be reduced.

  For various parts and materials used in various products such as home appliances and information devices, it is desirable to collect all parts and materials for each part and material, but reliable recycling technology has not been established. Incinerate the collected products and use the incinerated materials for building-related materials. For example, the liquid crystal panel may be incinerated and recycled as a roadbed material.

In order to recycle the used material without incineration as much as possible, a processing technique for improving the reuse rate of various materials and the like in the recycling of the liquid crystal panel has been proposed (for example, see Patent Document 1). . According to the proposal, the process of mechanically peeling the polarizing plate from the liquid crystal panel, the process of recovering the liquid crystal, the process of sorting the used glass substrates by type, and the The liquid crystal, glass and metal can be recovered by providing a processing step of removing the metal thin film formed on the substrate.
Japanese Patent Laid-Open No. 2001-305502 (FIG. 11)

  However, among liquid crystal panels, a relatively large panel, for example, a liquid crystal panel used in a television set and the number of liquid crystal panels collected is not enormous. Although it is easy, in the case of a small liquid crystal panel used for a mobile phone, a liquid crystal projector, etc., since the liquid crystal panel itself is small, the peeling operation of the polarizing plate becomes complicated, so that the polarizing plate peeling process takes a long time. It will be.

  In particular, in the case of a liquid crystal panel used for a mobile phone, the number of liquid crystal panels to be collected is enormous, so that it takes a long time to process one liquid crystal panel, which cannot be substantially recycled.

Further, in the sorting operation for extracting the glass, the sorting operation must be performed for each type of glass, and the sorting operation for a huge amount of liquid crystal panels cannot be substantially performed.
Furthermore, even if the number of recovered liquid crystal panels is enormous, it is not preferable to incinerate all the enormous numbers of liquid crystal panels because toxic substances may be generated during incineration.

  Accordingly, the present invention has been made in view of the above-described problems, and provides a method for easily and easily treating a waste liquid crystal panel in a short time while collecting the liquid crystal without incinerating the waste liquid crystal panel. For the purpose.

The method for treating a waste liquid crystal panel according to the present invention includes a polarizing plate treatment step of performing a polarizing plate treatment for removing or curing a polarizing plate of a waste liquid crystal panel by dissolving the polarizing plate with a solvent having solubility in the polarizing plate, A panel pulverizing step for pulverizing the waste liquid crystal panel subjected to plate treatment; and a liquid crystal extracting step for extracting liquid crystal from the pulverized waste liquid crystal panel.
According to such a configuration, the waste liquid crystal panel can be processed in a short time and easily while collecting the liquid crystal without burning the waste liquid crystal panel.

In the method for treating a waste liquid crystal panel of the present invention, the curing is preferably performed by irradiating with ultraviolet rays.
According to such a structure, a polarizing plate process can be performed easily and a panel grinding process can be performed reliably.

In the method for treating a waste liquid crystal panel according to the present invention, the liquid crystal extraction step may include a cleaning liquid containing at least the liquid crystal and water after cleaning the crushed material to which the liquid crystal has adhered at a first temperature. While the liquid crystal and the water are both dissolved, the liquid crystal and the water are dissolved and undissolved in a second temperature that is different from the first temperature, and an extract that exhibits different states is used. A first step of preparing a solution by dissolving in the extract at the temperature, and changing the temperature of the solution from the first temperature to the second temperature, so that either the liquid crystal or the water It is desirable to include a second step of separating the liquid crystal and the water in a state where one of them is dissolved in the extract.
According to such a configuration, liquid crystal extraction can be efficiently realized at low cost.

Embodiments of the present invention will be described below with reference to the drawings.
Based on FIG. 1, the processing method of the waste liquid crystal panel concerning this Embodiment is demonstrated. FIG. 1 is a flowchart showing a processing flow of the waste liquid crystal panel according to the present embodiment.

Waste liquid crystal panels are those discarded and collected in the market, those collected as defective products in the manufacturing process, and the like. Since the liquid crystal panel is built in a device such as a mobile phone, the built-in liquid crystal panel is taken out from the device, and the taken-out liquid crystal panel, that is, the waste liquid crystal panel is subjected to processing according to the present embodiment. Done. The waste liquid crystal panel processed in the present embodiment may be either in a state where the flexible printed circuit board is attached or only in a state where the flexible printed circuit board is removed.
As shown in FIG. 1, the processing of the waste liquid crystal panel according to the present embodiment includes three processing steps of polarizing plate processing, panel pulverization processing, and liquid crystal extraction processing. Each step will be described in order.

(Polarizing plate treatment process)
First, polarizing plate processing, which is processing for a polarizing plate of a waste liquid crystal panel, is performed (step (hereinafter referred to as S) 1). Polarizing plate treatment S1 is a polarizing plate dissolution and removal treatment in which the polarizing plate is dissolved and removed with an organic solvent that is soluble in the polarizing plate, or the polarizing plate is cured by irradiating the polarizing plate with ultraviolet rays from an ultraviolet lamp. This is a polarizing plate curing process. Since the polarizing plate is in the form of a film, the liquid crystal panel to which the polarizing plate is attached cannot be sufficiently pulverized in the next pulverization step. If the pulverization is not sufficient, the liquid crystal cannot be sufficiently extracted as will be described later, so that a polarizing plate treatment is required so that the pulverization can be sufficiently performed.

  According to the polarizing plate dissolution and removal treatment, since the material component of the polarizing plate is removed, the improvement of the extraction rate in the liquid crystal extraction treatment to be described later, and the raw material quality of the glass raw material finally provided to the glass raw material user etc. It becomes an improvement. Further, according to the polarizing plate curing process, the panel pulverization process performed before the liquid crystal extraction process can be easily and reliably performed, so that the liquid crystal extraction process described later can be performed reliably.

(Panel crushing process)
Next, a pulverization process is performed on the waste liquid crystal panel subjected to the polarizing plate treatment (S2). In the panel crushing process S2, the waste liquid crystal panel is shattered by applying mechanical pressure or shear stress to the waste liquid crystal panel with a waste crusher such as a screw crusher. The waste liquid crystal panel is pulverized to a size of, for example, 1 mm or less by the waste pulverizer, and becomes a pulverized product. Here, the size of each pulverized product is 1 mm or less because the liquid crystal enters between thin glass substrates, that is, the liquid crystal adhering to the corner that becomes the bag path cannot be extracted. To prevent. As a result, the crushed material has no such corners, so that the liquid crystal extraction rate can be increased in the liquid crystal extraction process described later.

(Liquid crystal extraction process)
Next, a liquid crystal extraction process is performed on the pulverized product 1 (S3). The liquid crystal extraction process S3 includes the following two steps, that is, a first step and a second step.
First, the first step will be described. FIG. 2 is a diagram for explaining the flow of liquid crystal extraction processing according to the present embodiment.

  The pulverized product 1 is washed stepwise by immersing the pulverized product 1 in a multistage manner as shown in FIG. 2 with the first cleaning solution 2a, the second cleaning solution 2b, the third cleaning solution 2c,. As a result, the pulverized product 1 is washed and no liquid crystal is attached to the pulverized product 1. Instead, the cleaning liquids 2a, 2b, 2c,... Contain at least water and liquid crystal that is the object to be cleaned.

  Since the pulverized product 1 is immersed in the cleaning liquids 2a, 2b, 2c,... (Hereinafter sometimes collectively referred to as the cleaning liquid 2) in order, the concentration of the liquid crystal in the cleaning liquid 2 is the first cleaning liquid 2a. Has the highest liquid crystal density. Incidentally, the concentration of the liquid crystal contained in the cleaning liquid 2 is preferably 5% by mass or less, and if it exceeds 5% by mass, poor cleaning due to re-contamination of the liquid crystal or the like occurs. The liquid crystal is not particularly limited as long as it is a liquid crystal compound capable of forming a liquid crystal layer, and there is no particular limitation on the number and type of chemical substances forming the liquid crystal compound.

  Moreover, the cleaning liquid 2 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. Commercially available products include Sunwash RE (manufactured by Lion Corporation), Sunwash LH-8000 (manufactured by Lion Corporation), and the like.

  In that case, it is preferable that the washing | cleaning liquid 2 contains 20-60 mass% of these surfactants. If the amount is less than 20%, a sufficient liquid crystal cleaning effect cannot be obtained. If the amount exceeds 60% by mass, problems such as poor cleaning due to high concentration and poor rinsing (residual failure) occur. Furthermore, the cleaning liquid may contain liquid crystal, water, and other components of the surfactant as long as they do not interfere with the cleaning effect of the liquid crystal. Furthermore, in order to wash the liquid crystal adhering to the pulverized product 1 more efficiently, a treatment such as propagation of ultrasonic waves to the cleaning liquid 2 may be performed while the pulverized product 1 is immersed.

  In the first step, the cleaning solution 2 is dissolved in the extract under conditions where the liquid crystal and water are dissolved to prepare the solution 3. This extract solution dissolves both liquid crystal and water at a first temperature, and exhibits a different state in which liquid crystal and water are dissolved and not dissolved at a second temperature different from the first temperature. It is. Examples of the substance 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 thereof include glycol ether, ethylene glycol ether, and propylene glycol ether. 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 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.

In addition, when the cleaning liquid further contains a surfactant, the surfactant is also dissolved in the extract.
When preparing a solution, 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, the solution does not become a uniform solution, or there arises the problem of volatilization or deterioration of the solution due to heating. In addition, if the reaction time is too long, problems such as an increase in the size of the apparatus in order to ensure the process capability will occur with respect to an increase in cycle time and an increase in processing time. Furthermore, it is preferable to mix a solution so that a washing | cleaning liquid and an extract may be 30-70 mass% and 70-30 mass%, respectively. The solution may be stirred as appropriate.

Next, the temperature of the solution 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 under conditions where either one of the liquid crystal or water is dissolved. Further, 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.

  As shown in FIG. 2, since the liquid crystal component 4a is formed as a supernatant in a state 4b in which water is dissolved in the extract, the supernatant 4a is separated using a method such as an oil / water separation method or a stationary separation method. be able to.

Further, a more preferable processing method for the liquid crystal content will be described with reference to FIG. FIG. 3 is a diagram for explaining a more preferable processing method for the liquid crystal content.
A deactivator for deactivating the surfactant is added to the liquid crystal component containing the liquid crystal and the surfactant. As the quencher, 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.

  As shown in FIG. 3, a liquid crystal is formed as a supernatant 5a by adding a quencher to the liquid crystal component. The supernatant 5a can be separated from the surfactant-containing liquid 5b containing a surfactant by using 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 the liquid crystal component 4a. 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 drainage does not contain liquid crystal, it is environmentally friendly.
In addition, in the 1st process mentioned above, it is preferable to carry out as follows about the process of the extraction solution 4b produced | generated when isolate | separating the liquid-crystal part 4a in the state which water melt | dissolved in the extract. 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 reused as a raw material for the first step, and the liquid crystal cleaning liquid can be processed more efficiently.

  As described above, when the liquid crystal is extracted from the pulverized product 1 through the processing of the first step and the second step, the pulverized product 1a left after the liquid crystal is extracted is included in the liquid crystal panel. Including various metals. In this state, the pulverized product 1a can be delivered to a glass manufacturer or the like as a glass raw material.

  In a glass manufacturer or the like, if it is a construction-related product, if it is a glass product that does not have any problem even if it contains some metal, the pulverized product 1a can be melted as it is and used as a raw material for the glass product. Or the crushed object 1a can be utilized for products, such as a crafts product and a tile of the use which does not have influence even if a trace amount metal is contained.

  Note that the glass manufacturer may extract the contained metal from the pulverized material 1a by a known processing method for extracting various metals from the pulverized material 1a, and reuse the metal and the glass respectively. Examples of the metal include valuable materials such as indium, copper, and gold.

  As described above, according to the present embodiment, since the waste liquid crystal panel is not incinerated for reuse as a roadbed material as in the prior art, no toxic substance is generated during incineration. Further, in order to recover the liquid crystal and to reuse the glass portion, a waste liquid crystal panel processing method can be realized in which the waste liquid crystal panel is processed in a short time and easily.

In the above description, the example of the waste liquid crystal panel used for a mobile phone or the like has been described. However, even a relatively large panel, for example, a liquid crystal panel used for a television device or the like, relates to the present embodiment. Processing can be applied.
The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

The flowchart which shows the flow of a process of the waste liquid crystal panel concerning this Embodiment. The figure for demonstrating the flow of the liquid-crystal extraction process concerning this Embodiment. The figure for demonstrating the more preferable processing method of the liquid-crystal part concerning this Embodiment.

Explanation of symbols

1, 1a pulverized product, 2 washing solution, 3 solution, 4a liquid crystal component, 4b extraction solution, 5a liquid crystal supernatant, 5b surfactant-containing solution

Claims (3)

A polarizing plate treatment step of performing a polarizing plate treatment for removing or curing the polarizing plate of the waste liquid crystal panel by dissolving it in a solvent having solubility in the polarizing plate;
A panel crushing step of crushing the waste liquid crystal panel treated with the polarizing plate;
A liquid crystal extraction step of extracting liquid crystal from the pulverized waste liquid crystal panel,
A method for treating a waste liquid crystal panel, comprising:   The method of treating a waste liquid crystal panel according to claim 1, wherein the curing is performed by irradiating ultraviolet rays. In the liquid crystal extraction step, the washing liquid containing at least the liquid crystal and water after washing the pulverized material to which the liquid crystal is adhered dissolves the liquid crystal and the water together at a first temperature, At a second temperature different from the first temperature, an extract solution in which the liquid crystal and the water are different from each other in a dissolved state and an insoluble state is used, and the dissolved solution is dissolved in the extract solution at the first temperature. In a state where the first step to create, 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, The method for treating a waste liquid crystal panel according to claim 1, further comprising a second step of separating the liquid crystal and the water.

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