JPH06287261A - Method for purifying novolak resin - Google Patents

Abstract

PURPOSE:To obtain a method for purifying a novolak resin, capable of providing the novolak resin reduced in impurities by removing impurities contained in the novolak resin. CONSTITUTION:Impurities in a novolak resin is eluted and removed by bringing the novolak resin into contact with water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying a novolak resin which removes the impurities from a novolak resin containing impurities such as additives.

[0002]

2. Description of the Related Art Conventionally, for cleaning semiconductor devices, printed circuit boards and the like, specific flon and chlorine-based solvents such as 1,1,1-trichloroethane have been used. However, since the possibility of ozone depletion was pointed out, 1995
It was decided to abolish the specified CFCs at the end of the year. Therefore, also in Japan, mainly in the electric and electronic industries, development of alternative CFCs for cleaning in place of the above specific CFCs is being actively carried out. At present, alternative CFCs, which are roughly classified into two types, solvent-based cleaning agents and water-based cleaning agents, have been developed.
All of the above solvent-based cleaning agents are flammable except halogenated hydrocarbon-based cleaning agents, and precautions against fire are necessary and explosion-proof measures are essential when used. Also,
Careful handling due to toxicity. On the other hand, the above-mentioned water-based detergents are basically non-flammable and have very little danger, and therefore research and development have been conducted mainly on these recently. The above-mentioned water-based cleaning agents are roughly classified into two types: an alkaline saponification type cleaning agent and a cleaning agent containing a neutral high concentration surfactant as a main component. The above-mentioned alkaline saponification type detergent is excellent in detergency, but has a problem that electromigration occurs when the detergent remains due to insufficient rinsing, for example. From such a viewpoint, an aqueous cleaning agent containing a neutral high-concentration surfactant as a main component has recently received attention.

On the other hand, the above-mentioned detergent containing a neutral high-concentration surfactant as a main component is a non-dangerous substance, is easy to handle, and can be rinsed with water, so that it is suitable for practical use. In this regard, the development of detergents containing this neutral high-concentration surfactant as the main component is being actively conducted. However, when cleaning is performed using this cleaning agent, treatment of waste water generated after cleaning poses a problem. This wastewater treatment is generally performed by treating the wastewater with a wastewater filtration system composed of activated carbon, ion exchange resin, activated sludge and the like.

[0004]

However, the above waste water filtration system has a problem that it is a large-scale facility and the treatment is too costly. Furthermore, the above-mentioned cleaning agent is composed of a nonionic surfactant and water, and there is also a problem that the nonionic surfactant cannot be sufficiently removed. In this way, in the treatment of wastewater generated during cleaning using a cleaning agent whose main component is a neutral high-concentration surfactant, which is attracting attention as an alternative CFC,
The fact is that an effective treatment method has not yet been established and its development is strongly desired.

In order to solve such a situation, the present applicant proposes a wastewater treatment method in which a novolac resin is a main component, and an alkaline substance is used in the main component to precipitate and separate a nonionic surfactant in the wastewater. Have filed an application (Japanese Patent Application No. 5-51779). However, when the supernatant treated by the above wastewater treatment method was analyzed, a substance having a high chemical oxygen demand (COD) value and not existing in the wastewater was detected. Therefore, even if this supernatant liquid is treated with activated sludge, activated carbon or the like, the COD value of the supernatant liquid is high, and high-level and high-cost treatment is required to treat the treatment liquid to a level at which it can be discharged.

The present invention has been made in view of the above circumstances, and provides a method for purifying a novolak resin, by which impurities contained in the novolac resin can be easily removed to obtain a novolac resin having less impurities. To that end.

[0007]

In order to achieve the above object, the method for purifying a novolak resin of the present invention is to bring water into contact with the novolac resin and to elute the impurities in the novolac resin to remove them. Take composition.

[0008]

That is, the present inventor analyzed the components in the supernatant liquid generated when wastewater treatment was performed using a novolac resin, and found that the components not contained in the wastewater were contained,
It was found that this is the cause of increasing the COD value of the supernatant treated with the wastewater. As a result of repeated research on the substance that causes the increase in the COD value, it was found that this substance is caused by the novolac resin. Then, as a result of repeated studies to remove impurities caused by this novolak resin, it was found that washing with water results in the elution of impurities in the supernatant liquid after washing to obtain a novolak resin having less impurities. Reached

Next, the present invention will be described in detail.

The method for purifying the novolak resin of the present invention comprises:
Novolac resin and water are used.

The novolak resin to which the present invention is applied is
There is no particular limitation, and conventionally known ones can be used. As the form of the novolac resin, it is preferable to use a granular form. The term "granular" is intended to include not only granular, powdery, flake-shaped, and marble-shaped particles, but also powdery particles formed into pellets by tableting or the like. And as the above-mentioned granular novolak resin, it is preferable to use a resin containing a novolac resin represented by the following general formula (1) as a main component. Particularly, the repeating number n in the general formula (1) is preferably 5 to 7. By using the repeating number n of 5 to 7, the separation of the nonionic surfactant in the waste water and the other components becomes more effective.

[0012]

[Chemical 1]

The method for purifying the novolac resin of the present invention is carried out, for example, as follows. That is, the novolac resin is mixed with water and stirred. Then, the precipitated substance composed of the novolac resin is separated into a supernatant, and the impurities in the novolac resin are eluted into the supernatant. Then,
The supernatant and the novolak resin are separated by centrifugation, dehydrator or the like to remove the supernatant. Further, when refining the novolac resin, the above operation is repeated. In this way, the impurities contained in the novolac resin are eluted in water and are removed together with the supernatant.

Impurities contained in the novolac resin are eluted in the supernatant produced when the novolac resin is purified by such a purification method. Then, as a method for separating the precipitating substance consisting of the novolac resin and the supernatant liquid and removing the supernatant liquid, it is not particularly limited to the above-mentioned device as long as it can be separated and removed.

As the water used in the above-mentioned purification method, for example, room temperature water at about 25 ° C. to warm water at about 80 ° C. is preferably used. Particularly preferred is warm water of about 50 ° C.

[0016]

As described above, the method for purifying a novolak resin of the present invention is to remove the impurities in the novolac resin by eluting it with water by contacting the novolac resin with water. Therefore, when the purified novolac resin is used as the wastewater treatment agent, the elution of impurities contained in the novolac resin in the supernatant is reduced, and the COD of the supernatant is reduced.
The value decreases. Therefore, the COD value and biochemical oxygen demand (BO) until the wastewater can be discharged by effectively treating the supernatant produced by the wastewater treatment with activated sludge, activated carbon, etc.
D) It becomes easy to set a value or the like.

Next, the present invention will be described in detail based on embodiments.

[0018]

Example 1 1000 liters of normal temperature water (25 ° C.) was added to 100 g of a powdery (particle size: 0.5 mm or less) novolak type phenol-formaldehyde resin, and the novolac resin was washed by stirring.

[0019]

Example 2 The novolac resin washed in Example 1 was
Further, it was washed in the same manner as in Example 1.

[0020]

Example 3 Normal temperature water was replaced with warm water at 50 ° C. The novolak resin was washed in the same manner as in Example 1 except for the above.

[0021]

Example 4 The novolak resin washed in Example 3 was
Further, washing was performed in the same manner as in Example 3.

[0022]

Example 5 The powdery novolac type phenol / formaldehyde resin was replaced with a marble type novolac type phenol / formaldehyde resin. Otherwise, Example 1
The novolak resin was washed in the same manner as.

[0023]

Example 6 The novolac resin washed in Example 5 was
Further, it was washed in the same manner as in Example 5.

[0024]

Example 7 Normal temperature water was replaced with warm water at 50 ° C. The novolak resin was washed in the same manner as in Example 5 except for the above.

[0025]

Example 8 The novolac resin washed in Example 7 was
Further, it was washed in the same manner as in Example 7.

The COD value of the cleaning liquid of each novolak resin thus washed was measured according to the acidic potassium permanganate method. The results are shown in Table 1 below. further,
The components in each of the above washing solutions were analyzed by gas chromatography (HP5971, manufactured by Hulet Packer).
As a result, most of the above components are phenol, 2,2'-
It was found to be methylenebis and 4,4'-methylenebis. The conditions for gas chromatography are column: HP-5 and carrier gas: He at 1 ml / min.

[0027]

[Table 1]

From the results shown in Table 1 above, it can be seen that a large amount of impurities are eluted from the novolac resin. Furthermore, it can be seen that by repeating the washing step, the amount of impurities eluted is reduced and the impurities are removed in the previous washing step.

Claims (1)

[Claims] 1. A method for purifying a novolac resin, which comprises contacting water with the novolac resin and eluting impurities in the novolac resin into water to remove the impurities.