KR101232334B1 - Refining method of organic solvent - Google Patents

Abstract

PURPOSE: A refining method of an organic solvent is provided to purify and separate propylene glycol monomethyl ether acetate from a waste organic solvent and to improve production yield and treatment amount. CONSTITUTION: A refining method of an organic solvent comprises: a step of preparing a waste organic solvent which comprises a first organic compound and a second organic compound and is used in a photoresist process; a step of putting an amine compound into the waste organic solvent and forming a second organic compound into a third organic compound which has a different boiling point than the first organic compound; and a step of obtaining a first organic compound by fractional distilling of the waste organic solvent. The amine compound is hydroxylamine, hydroxylamine sulfate, or hydroxylamine hydrochloride.

Description

Refining method of organic solvent

The present invention relates to a method for purifying an organic solvent, and more particularly, to a method for separating and purifying cyclonuclistanone and PMA contained in an organic solvent used in a photoresist process.

Lithography is widely used to manufacture electronic circuits, pixels, and the like in the manufacturing process of displays such as semiconductors and TFT-LCDs. This lithography is a method used to create a fine pattern on a substrate, a process of transferring the circuit pattern of the mask to the substrate by irradiating light through a mask on which a desired pattern is printed on the photoresist, the photoresist is applied The photoresist is generally composed of a binder component resins, photoinitiators, organic solvents, various pigments, dispersants, and other additives.

In the lithography process using the photoresist as described above, the photoresist may be deposited on an undesired portion, such as a photoresist coating nozzle, a coating peripheral device, or an edge of the substrate in the photoresist coating process. It may cause defects in the photoresist application process and must be removed. At this time, an organic solvent is used to remove unwanted photoresist. Therefore, the waste organic solvent after removing the photoresist includes components of the photoresist, that is, resins, photoinitiators, pigments, organic solvents, additives, and the like as impurities.

Such waste organic solvents contaminated with impurities may be incinerated, but not only harmful chemicals are generated during the incineration process, but also the useful value of the waste organic solvents itself decreases, and thus, recently generated waste organic solvents are reused in the display manufacturing process. Regeneration treatment with a high purity organic solvent is being performed.

Regeneration of the waste organic solvent is usually separated using fractional distillation using the difference in boiling point for each component, similar to the general method for purifying organic solvents. However, many other organic solvent impurities contained in the waste organic solvent have similar boiling points to the organic solvent to be recovered. These similar boiling point impurities are not easy to be separated by distillation of the organic solvent component to be recovered and require a very high number of distillation towers.

In particular, methyl 3-methoxypropionate and cyclohexanone, which are present as impurities in the waste organic solvent, are propylene glycol monomethylether acetate PMA. The boiling point was similar to that of fractional distillation. In particular, the problem was more serious when the content of cyclohexanone is high.

Therefore, in order to solve the above problem,

The problem to be solved by the present invention is to separate and purify cyclohexanone and propylene glycol monomethylether acetate (PMA) contained in the waste organic solvent, in particular, by chemical treatment of cyclohexanone To provide a purification method for separating cyclohexanone and propylene glycol monomethyl ether acetate from each other.

The problem to be solved of the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

Purification method of an organic solvent according to an embodiment of the present invention for achieving the problem to be solved, a) comprising a first organic compound and a second organic compound, to prepare a waste organic solvent used in the photoresist process B) adding an amine compound to the waste organic solvent to form the second organic compound as a third organic compound having a boiling point different from that of the first organic compound, and c) fractionally distilling the waste organic solvent. It is characterized by comprising the step of obtaining a first organic compound.

The boiling point of the first organic compound is lower than that of the third organic compound.

The step c) includes heating the waste organic solvent to a range of ± 10 ° C. of the boiling point of the first organic compound, fractionally distilling the first organic compound, and obtaining a vapor of the first organic compound. Characterized in that.

Cooling the steam to obtain a liquid phase of the first organic compound.

The amine compound is characterized in that the hydroxylamine (Hydroxylamine), hydroxylamine sulfate (Hydroxylamine sulfate) or hydroxylamine hydrochloride (Hydroxylamine hydrochloride).

The first organic compound is propylene glycol monomethylether acetate, the second organic compound is cyclohexanone, and the third organic compound is cyclohexanone oxime. It is done.

The boiling point of the cyclohexanone oxime is higher than that of the propylene glycol monomethyl ether acetate.

According to the present invention, cyclohexanone and propylene glycol monomethylether acetate (PMA) contained in the waste organic solvent may be separated and purified. In particular, a purification method for separating cyclohexanone and propylene glycol monomethyl ether acetate from each other by chemically treating cyclohexanone may be provided.

1 shows a gas chromatography analysis result according to Example 1.
2 shows a gas chromatography analysis result according to Example 2.
3 shows a gas chromatography analysis result according to Example 3.
4 shows a gas chromatography analysis result according to Example 4.
5 shows a gas chromatography analysis result according to Example 5.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.
In the present invention, the first organic compound is propylene glycol monomethylether acetate, the second organic compound is cyclohexanone, and the third organic compound is cyclohexanone oxime. .

Hereinafter, a method of purifying an organic solvent according to an embodiment of the present invention will be described.

One embodiment of the present invention is a method for purifying an organic solvent for reusing an organic compound contained in a waste organic solvent used in a photoresist process, the method for purifying an organic solvent according to an embodiment of the present invention is a) a first Comprising an organic compound and a second organic compound, and preparing a waste organic solvent used in the photoresist process, b) by introducing an amine compound into the waste organic solvent to the second organic compound and the first organic compound Forming a third organic compound having different boiling points; and c) fractionally distilling the waste organic solvent to obtain a first organic compound. Hereinafter, each step will be described in more detail.

First, a) comprising a first organic compound and a second organic compound, and looking at the step of preparing a waste organic solvent used in the photoresist process as follows.

The photoresist process is a process involved when forming a circuit or the like in a semiconductor process or when forming a color filter in a TFT-LCD process. After the pattern of the circuit or the color filter is formed in the photoresist process, the photoresist in the portion where the photosensitive reaction does not occur should be removed. It is also common to remove the pattern forming photoresist located on the pattern to produce the final product.

In order to remove such a photoresist, an organic solvent is used. On the other hand, the organic solvent used in the photoresist removal process is not discarded as it is, but is recovered and managed as a waste organic solvent and treated. This is because the components contained in the organic solvents contain chemicals with lethal toxicity that can cause environmental pollution.

Such waste organic solvents may include, for example, PMA and impurities. The impurities may be, for example, methyl 3-methoxypropionate (hereinafter referred to as 'MMP') cyclohexanone, other monomers, polymers, photopolymerization initiators, crosslinking agents or slurries. Can be.

At this time, the waste organic solvent may include, for example, about 75 to 85% PMA, 3 to 7% MMP, 1 to 3% cyclohexanone and other monomers, polymers, photopolymerization initiators, crosslinking agents or slurries. Can be.

Among them, the PMA contained in the waste organic solvent can be regenerated and reused in other photoresist processes. Thereby, the manufacturing cost of the process of manufacturing a semiconductor etc. can be saved.

However, in the organic solvent, the substances listed above are present in the form of a mixture, which must be fractionated and purified. Among them, the boiling point of PMA is 146 ° C, the boiling point of MMP is 143 ° C, and the boiling point of cyclohexanone is 155.65 ° C, so it is difficult to purify these substances by fractional distillation using boiling point. This is the cause of lowering the recovery rate of PMA. Meanwhile, in the present specification, it is assumed that PMA contained in the waste organic solvent is a first organic compound, and cyclohexanone is a second organic compound.

Accordingly, in order to improve the recovery of PMA, MMP or cyclohexanone can be changed to an organic compound having a boiling point significantly different from that of PMA, thereby improving the recovery of PMA. More details on this will be described later.

Next, a process of removing MMP from the substances listed above may be performed by adding a polymerization inhibitor to the waste organic solvent prepared as described above.

First, a polymerization inhibitor is put into a waste organic solvent. The polymerization inhibitor may prevent the polymerization reaction between PMA, MMP or other monomers or polymers contained in the waste organic solvent, thereby preventing the formation of other substances in the waste organic solvent. For example, an acrylate may be formed between materials contained in the waste organic solvent to cure the waste organic solvent, and the polymerization inhibitor may prevent the formation of the acrylate, thereby preventing the waste organic solvent from curing.

The polymerization inhibitor may be used in an amount of 0.1 to 5.0 wt% based on the total weight of the waste organic solvent. When the amount of the polymerization inhibitor is less than 0.1% by weight, the effect of preventing the polymerization reaction by the polymerization inhibitor may not occur. When the amount of the polymerization inhibitor exceeds 5.0 wt%, the effect of preventing the polymerization reaction by the polymerization inhibitor is not increased beyond the amount to be added, which may be undesirable from the viewpoint of economics.

As such a polymerization inhibitor, naphthoquinone may be used. Here, naphsoquinone may be solid content.

Subsequently, MMP is hydrolyzed as in the following formula (1).

At this time, an acid or alkali catalyst may be used to improve the reaction rate of the hydrolysis reaction. At this time, preferably a sulfuric acid catalyst may be used. As sulfuric acid, dilute sulfuric acid diluted 2 to 70% may be used. When sulfuric acid is diluted to less than 2%, it is difficult to use sulfuric acid in an aqueous solution, so sulfuric acid may not be uniformly dispersed in the waste organic solvent, and thus the catalytic reaction by sulfuric acid may not be performed smoothly. If the sulfuric acid is diluted more than 70%, the sulfuric acid content is small, the catalytic reaction is relatively small, the rate of the net decomposition can be slowed down.

Hydrolyzed MMP can be converted into organic compounds of methanol and 3-Methoxypropionic acid. That is, MMP can be changed to two organic compounds.

At this time, the boiling point of methanol is 65 ° C., and the boiling point of 3-methoxypropionic acid is 236.9 ° C. (at atmospheric pressure). In view of the fact that the boiling point of PMA is 146 DEG C, hydrolysis changes MMP into methanol having a boiling point lower than that of PMA and 3-methoxypropionic acid having a boiling point higher than that of PMA.

On the other hand, the hydrolysis reaction is preferably carried out for 0.5 to 4 hours in a temperature atmosphere of 20 ℃ to 120 ℃.

If the hydrolysis reaction is carried out at less than 20 ℃, the reaction may be very slow, or the hydrolysis reaction itself may not occur. When the hydrolysis reaction is performed above 120 ° C, monomers, slurries and the like contained in the waste organic solvent may be mixed and distilled, thereby reducing the efficiency of the purification process.

On the other hand, if the hydrolysis reaction proceeds in less than 0.5 hours, it may be difficult to expect the hydrolysis of the MMP is not enough time for the MMP is hydrolyzed. If the hydrolysis reaction proceeds for more than 4 hours, the hydrolysis of the MMP may be sufficient, but since the hydrolysis reaction may already be saturated, it may be difficult to expect any further hydrolysis reaction even beyond this time.

Subsequently, MMP is decomposed to remove the methanol contained in the waste organic solvent.

Removing methanol may be carried out by distillation of the waste organic solvent under reduced pressure in a temperature atmosphere lower than the boiling point of PMA. That is, it can be carried out at 66 ℃ or more higher than the boiling point of methanol 65 ℃. However, since the temperature must be lower than the boiling point of 146 ℃ PMA boiling point, the temperature range of the reduced pressure distillation of the waste organic solvent to remove methanol is 66 It is preferable that it is C-120 degreeC.

At this time, the air pressure may be 650 to 750 mmHg. As such, the reason for carrying out the reduced pressure distillation is to immerse the slurry contained in the waste organic solvent to more easily separate them. That is, the slurry contained in the waste organic solvent by distillation under reduced pressure can be immersed in the bottom of the container in which the waste organic solvent is loaded. If the waste organic solvent is passed through a filter, the immersed slurry can be separated from the waste organic solvent. . Here, a membrane membrane filter made of Teflon may be used as the filter medium.

Since the MMP can be effectively removed from the waste organic solvent by the above-described steps, the purity of PMA contained in the waste organic solvent can be further increased. In summary, while the waste organic solvent undergoes a hydrolysis reaction and a reduced pressure distillation step, the waste organic solvent may have substances having a boiling point higher than 66 ° C. to 120 ° C., which is a temperature range during the reduced pressure distillation. That is, for example, PMA, 3-methoxypropionic acid, cyclohexanone, etc. may remain in the waste organic solvent.

Next, b) adding an amine compound to the waste organic solvent to form the second organic compound as a third organic compound having a boiling point different from that of the first organic compound. As described above, in this step, it is assumed that the first organic compound is PMA, and the second organic compound is cyclohexanone.

First, an amine compound is thrown into the waste organic solvent. Here, the amine compound may be, for example, hydroxylamine, hydroxylamine sulfate, or hydroxylamine hydrochloride.

For example, hydroxylamine, hydroxylamine sulfate, or hydroxylamine hydrochloride are added to the waste organic solvent, and the hydroxylamine, hydroxylamine sulfate, or hydroxylamine hydrochloride and cyclohexanone are heated at a temperature of 50 to 120 ° C. The reaction is carried out at 0.5 to 2 hours. Thereby, cyclohexanone is changed into cyclohexanone oxime which is a 3rd organic compound as shown in following General formula (2).

On the other hand, when the reaction is carried out at less than 50 ℃, the reaction may be very slow, or the reaction itself of the production of cyclonuclinon oxime may not be made. When the reaction is performed in excess of 120 ℃, monomers, slurries and the like contained in the waste organic solvent may be mixed distillation, the efficiency of the purification process may be reduced.

On the other hand, if the reaction proceeds in less than 0.5 hours, the cyclonucleanone may not be sufficiently changed to cyclonuxanone oxime. If the reaction proceeds for more than 2 hours, the change to cyclonuxanone oxime may be sufficiently made, but since the change to cyclonuxanone oxime may already be saturated, even more than the above time to further cyclonuxanone oxime Can be difficult to expect.

On the other hand, after the reaction, the waste organic solvent may include a salt, in order to remove this may be added to the diethanolamine (Diethanolamine). Thereby, the purity of PMA can be improved more.

The boiling point of the cyclohexanone oxime which is the third organic compound thus formed is 206 to 210 ° C. That is, the boiling point (146 degreeC) of the PMA which is a 1st organic compound, and the boiling point of cyclohexanone oxime which is a 3rd organic compound differ from each other. More specifically, it can be seen that the boiling point of PMA which is the first organic compound is lower than that of cyclohexanone oxime which is the third organic compound.

Next, c) the steps of obtaining the first organic compound by fractional distillation of the waste organic solvent are as follows. In this case, the waste organic solvent may be heated to a range of ± 10 ° C. of the boiling point of the first organic compound, and the first organic compound may be fractionally distilled. The third organic compound, cyclohexanone oxime, is a conventional cyclohexa It has a higher boiling point than rice paddies. The boiling point of cyclohexanone oxime is 206-210 degreeC. That is, it has a boiling point higher than 146 degreeC which is the boiling point of PMA. Thereby, the separation of the PMA and the cyclohexanone oxime can be facilitated through fractional distillation. That is, the cyclohexanone may be changed to a cyclohexanone oxime to separate the PMA and the cyclohexanone.

In addition, 3-methoxypropionic acid remaining in the waste organic solvent by the hydrolysis process of MMP also has a higher boiling point than PMA. That is, the boiling point of 3-methoxypropionic acid is 236.9 ° C. That is, it has a boiling point higher than 146 degreeC which is the boiling point of PMA. Thereby, separation of PMA and 3-methoxypropionic acid through fractional distillation can be facilitated. As a result, the MMP substantially contained in the waste organic solvent can be completely removed.

More specifically, the waste organic solvent containing cyclohexanone oxime and 3-methoxypropionic acid at normal pressure is heated in a temperature atmosphere of ± 10 ° C. at the boiling point of PMA. That is, since the boiling point of PMA is 146 degreeC, waste organic solvent is heated in the temperature atmosphere of 136-156 degreeC, and PMA is fractionated. Thereby, PMA having a boiling point lower than the boiling points of cyclohexanone oxime and 3-methoxypropionic acid will be distilled, and cyclohexanone oxime and 3-methoxypropionic acid having a boiling point higher than the temperature range are used for waste organic matter. Will remain in place. That is, the PMA distilled at the top of the reactor on which the waste organic solvent is supported can be obtained.

When the waste organic solvent is heated in the above temperature range, PMA (boiling point 146 ° C.) having a lower boiling point than cyclohexanone oxime (boiling point of 206 to 210 ° C.) and 3-methoxypropionic acid (boiling point of 236.9 ° C.) is vapor phase. The change will be distilled to the top of the reactor. Distilled PMA is obtained at the top of the reactor to separate PMA, 3-methoxypropionic acid and cyclohexanone oxime in waste organic solvent.

Thereafter, the obtained gaseous PMA may be cooled to 146 ° C. or lower to obtain a liquid PMA. On the other hand, in order to remove the slurry contained in the PMA obtained in the gas phase or liquid phase, the gas phase PMA or liquid PMA is passed through a filter. Here, a membrane membrane filter made of Teflon may be used as the filter medium.

According to the above method, the PMA contained in the waste organic solvent can be separated from other impurities to purify the waste organic solvent with PMA having a purity of approximately 99.0% or more.

Hereinafter, the contents of the present invention will be described in detail by way of examples, but the scope of the present invention is not limited to these examples, and the examples are only presented for easy understanding of the contents of the present invention.

Example -One

First, a gas chromatography (Gas Chromatography, hereinafter 'G / C') analysis of the waste organic solvent used in the photoresist process is shown in FIG. As can be seen in Figure 1, it can be seen that the waste organic solvent contains MMP and cyclohexanone (denoted as 'Anone' in FIG. 1) as impurities, and other impurities are also included. have. Representatively, propylene glycol monomethyl ether (PGME) is also included in the waste organic solvent.

Example -2

To remove MMP, 0.2 g of Naphthoquinone was added to 500 ml of waste organic solvent containing impurities containing MMP as a polymerization initiator, 7 ml of 50% dilute sulfuric acid was added and stirred for 30 minutes, followed by stirring at 100-120 ° C. It heated and made it hydrolyze for 2 hours or more. At this time, after checking the reaction process by G / C to find the end point of the content of 3-methoxypropionic acid is 0.5% or less, and then vacuumed to 700 ~ 730mmHg, the waste oil in a temperature atmosphere of 90 to 110 ℃ The solvent was distilled under reduced pressure.

At this point, the impurity treatment stopped distillation to obtain 438 g of waste organic solvent, and the G / C analysis of the waste organic solvent first distilled is shown in FIG. 2.

Referring to Figure 2, it can be seen that the MMP was significantly reduced compared to Example 1 before the hydrolysis reaction by the hydrolysis reaction.

Example -3

To 200 g of the waste organic solvent obtained in Example 2, 2.5 g of hydroxylamine sulfate and 3.5 ml of diethanolamine were added and reacted at 100 to 120 ° C. for 2 hours. The results of G / C for this are shown in FIG. 3.

Referring to FIG. 3, it can be seen that the cyclonucleone (Anone) of FIGS. 1 and 2 has been changed to cyclohexanone oxime (denoted as 'Oxime' in FIG. 3).

Example -4

To 200 g of the waste organic solvent obtained in Example 2, 3.0 g of hydroxylamine hydrochloride and 3.0 ml of diethanolamine were added and reacted at 100 to 120 ° C. for 2 hours. The results of G / C for this are shown in FIG. 4.

Referring to FIG. 4, it can be seen that the cyclonucleone (Anone) of FIGS. 1 and 2 is changed to cyclohexanone oxime (denoted as 'Oxime' in FIG. 4).

Example -5

The waste organic solvents of Examples 3 and 4 were fractionated by distillation under a atmospheric pressure of 145 to 150 ° C. At this time, the amount of PMA obtained was 152g. Meanwhile, the G / C results of the obtained PMA are shown in FIG. 5.

Referring to FIG. 5, it was found that the obtained PMA showed little MMP, cyclonucleanone or other impurities. The purity of the obtained PMA was about 99.4%.

According to the method for regenerating the waste organic solvent according to the present invention, three primary colors (red, green, blue) pigment spray nozzles are manufactured when manufacturing a color filter for implementing a color screen in which a color filter and a TFT-array substrate are the main components. It is used to clean the pigment nozzle attached to the filter and remove the photoresist applied to the color filter and mix the polymerization inhibitor with the waste organic solvent discharged as waste, hydrolyze the first distillation, mix the amine compound and perform the second distillation. It is possible to purify the PMA of high purity (purity of 99.9% or more).

In addition, when the present invention is applied to production, it is possible to achieve a production yield improvement and a breakthrough throughput improvement compared to the conventional production method. According to the present invention, by removing the unnecessary organic solvent components contained in the waste PMA generated in the color filter manufacturing process to be reused in the color filter manufacturing process it can be reused in the waste solution source to achieve environmental problems and cost reduction Can be.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be manufactured in various forms, and a person of ordinary skill in the art to which the present invention belongs may have the technical idea of the present invention. However, it will be understood that other specific forms may be practiced without changing the essential features. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (7)

a) preparing a waste organic solvent comprising a first organic compound and a second organic compound and used in a photoresist process;
b) injecting an amine compound into the waste organic solvent to form the second organic compound as a third organic compound having a boiling point different from that of the first organic compound; And
c) fractionating the waste organic solvent to obtain a first organic compound,
The amine compound is hydroxylamine (Hydroxylamine), hydroxylamine sulfate (Hydroxylamine sulfate) or hydroxylamine hydrochloride (Hydroxylamine hydrochloride),
The first organic compound is propylene glycol monomethyl ether acetate,
The second organic compound is cyclohexanone,
The third organic compound is a cyclohexanone oxime (Cyclohexanone Oxime) characterized in that the purification method of the organic solvent. The method according to claim 1,
The boiling point of the first organic compound is lower than the boiling point of the third organic compound. The method of claim 2,
The step c) includes heating the waste organic solvent to a range of ± 10 ° C. of the boiling point of the first organic compound, fractionally distilling the first organic compound, and obtaining a vapor of the first organic compound. Purification method of an organic solvent, characterized in that. The method of claim 3,
Cooling the steam to obtain a liquid phase of the first organic compound characterized in that the organic solvent. delete delete The method according to claim 1,
The boiling point of the cyclohexanone oxime is higher than the boiling point of the propylene glycol monomethyl ether acetate.

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