JP4307499B2 - Method for producing MEK-modified resorcin formalin resin in which recovery and reuse of specific raw materials are performed in parallel - Google Patents

Description

The present invention relates to improvements in the production process of methyl ethyl ketone-modified resorcin formalin resin (hereinafter abbreviated as MEK-modified resorcin formalin resin) and specific raw materials (methyl ethyl ketone (hereinafter abbreviated as MEK), methanol and calcium chloride) used in the production. It relates to the reuse method.
More particularly, the present invention, resorcinol in addition to the aforementioned ingredients, water, and using hydrochloric acid and formalin, etc., relates to efficient recovery and recycling method of the specific raw materials from the waste liquid containing these chemical substances is there.

Raw material is calcium chloride, water, MEK, resorcinol, in that hydrochloric a predetermined amount added completely dissolved in the manufacturing process of the MEK-modified resorcinol-formalin resin to carry out the reaction by dropwise addition of formalin, and the aqueous layer containing calcium chloride After separating the MEK layer and removing the calcium chloride precipitated by azeotropic dehydration of the MEK layer by pressure filtration, the pH of the water and MEK was adjusted with ammonia water after solvent replacement by distillation, and the MEK-modified resorcin formalin resin was removed. It has been reported that it was manufactured. (For example, see Patent Document 1)

Conventionally, resorcin formalin resin is used for adhesives, plywood, laminated materials, surface coatings, etc. because of its fast curing speed, and especially has excellent adhesion to rubber and fibers. It is used as

Formalin contains about several to 10% of methanol as a stabilizer, and formalin is used as a condensing agent when producing MEK-modified resorcin formalin resin. However, the waste liquid from each manufacturing process contains many impurities in addition to the stabilizing agent methanol, and methanol recovery from the aqueous layer separated from the MEK layer after the formalin dripping and liquid-liquid heterogeneous reaction is not possible. This is an indispensable operation.

It is also known that the presence of trace amounts of inorganic salts such as calcium chloride in the MEK-modified resorcin formalin resin decreases the adhesion to tires and fibers used as adhesives. As a method for removing calcium, there is a method in which calcium chloride dissolved in water contained in the MEK layer is removed by pressure filtration after precipitation by azeotropic dehydration of the MEK layer.
However, this method of removing calcium chloride by pressure filtration is cumbersome and time consuming, and the removal effect is not sufficient and there is room for improvement.

WO2005 / 035611A1 publication

Methanol is contained in the formalin from about several percent to about 10%, and the concentration of methanol contained in the recovered water reused in the process of producing the MEK-modified resorcin formalin resin increases with the number of reuses . Increased concentration of methanol contained in the solution before the reaction may adversely affect the quality, such as increasing the proportion of MEK-modified resorcin formalin resin, which is a reaction product, of five or more nuclei (polynuclear). is there.

An object of the present invention is to provide a specific raw material (calcium chloride, MEK) used for the production of MEK-modified resorcin formalin resin and a method for recovering and reusing methanol contained in formalin, and a part of the production process. The purpose of this is to stabilize the quality by controlling the calcium chloride concentration in the final product to 100 ppm or less.

In the present invention, (A) 20 to 40 parts by mass of resorcin is added to 100 parts by mass of an aqueous solvent, (B) 20 to 80 parts by mass of calcium chloride is added to 100 parts by mass of water, and (C) methyl ethyl ketone. (Hereinafter abbreviated as MEK) is added in an amount of 10 to 100 parts by mass with respect to 100 parts by mass of (A) resorcin, stirring to form a two-phase system in which no solids remain, and (D) hydrochloric acid as a catalyst is added, (E) 1-40% formalin is added dropwise with stirring to form a ratio of formaldehyde / resorcin = 0.3-0.7 mol with respect to (A) resorcin, and the liquid-liquid heterogeneous reaction proceeds. The reaction product layer after removal of the aqueous layer (0) was allowed to stand to separate into two layers, and water was added to the MEK layer (0), which is the reaction product layer, in an amount equal to or 5 times the amount of the reaction product, and washed with water. Let stand and separate into two layers, remove the aqueous layer (1) and wash with water Further, the water layer (2) is removed by performing the operation one or more times to obtain a MEK layer (2) containing a MEK-modified resorcin formalin resin, and 2.5 to 5 times the mass of this MEK layer. Add water, distill by adding 1-30% ammonia water, and (C) MEK is removed by distillation to finally give a moderate fluidity of reaction product concentration 30-80%, pH 6-10. Having a calcium chloride concentration of 100 ppm or less, and having a peak area corresponding to the resorcin monomer of 3 to 9% of the total peak area obtained by gel permeation chromatography analysis, Specific raw materials (calcium chloride, MEK) and (E) forma in the above-described production process for obtaining an MEK-modified resorcin formalin resin aqueous solution having a peak area corresponding to the above of 30 to 55% A method for producing a MEK-modified resorcin formalin resin, wherein the recovery and reuse of methanol contained in phosphorus is performed in parallel. However, the numerical value in () represents the processing order.

Upon the onset Ming, to produce a MEK-modified resorcinol-formalin resin, aqueous layer of methanol during the manufacturing process to be contained in formalin (0), the aqueous layer (1), aqueous layer (2), and MEK layer (2 ) vacuum distilled from a further recovered by rectification method for producing a MEK-modified resorcinol-formalin resin, characterized in that recovery and reuse of methanol is carried out in parallel.

This onset Ming, for the manufacture of a MEK-modified resorcinol-formalin resin, more calcium chloride concentration in the aqueous phase after removal of methanol by vacuum distillation from the aqueous layer during the manufacturing process (0) to manage the start of the reaction when the concentration, The MEK-modified resorcin formalin resin production method is characterized in that reuse is performed in parallel as a specific raw material (calcium chloride) at the start of the reaction.

This onset Ming, MEK layer of MEK-modified resorcinol-formalin resin in the manufacturing process (2), the aqueous layer (1) and to simple distillation from the aqueous layer (2), followed by rectification, recovery of a specific material (MEK) And a method for producing a MEK-modified resorcin formalin resin, wherein the reuse is performed in parallel.

MEK is used not only as a ketone-modified resorcin formalin resin but also as a liquid-liquid heterogeneous reaction solvent, and functions to control the molecular weight distribution of the target resin by utilizing the difference in solubility. Furthermore, it is also used as an extraction solvent for MEK-modified resorcin formalin resin.

The MEK recovery method can be separated and recovered mainly by simple distillation from the MEK layer (2) in the production process and further rectification. Moreover, high-purity MEK can also be recovered by rectification from a MEK solution containing water obtained by removing methanol and the like from the aqueous layer (1) and the aqueous layer (2) separated from the MEK layer by a vacuum distillation method.

In the finally obtained MEK-modified resorcin formalin resin, the molecular weight MW of the component in which methyl ethyl ketone is incorporated into the molecule is MW = 110 × k + 72 × l + 30 × m−18 × n (k, l, m, n Represents an integer). Here, 110 is the molecular weight of resorcin, k is the number of resorcin units, 72 is the molecular weight of methyl ethyl ketone, l is the number of methyl ethyl ketone units, 30 is the molecular weight of formaldehyde, m is the number of formaldehyde units, 18 is the molecular weight of water, and n is the water molecular weight. The number of units. The relationship between these numerical values is k + l + m≈n + α, 2 ≦ k, 1 ≦ l, 0 ≦ m, and α = 1 or 2. The component in which this methyl ethyl ketone is incorporated into the molecule is obtained by liquid chromatography analysis as a peak having a longer retention time than the pentanuclear component that does not contain methyl ethyl ketone in the molecule. Can be grasped. In the present invention, the resorcin n-nucleus means both the n-nucleus of the resorcin formalin resin itself and a ketone-modified resorcin formalin resin having a molecular weight slightly higher than that of the resorcin formalin resin itself due to ketone modification. ing. In addition, the molecular weight of each n nucleus is determined based on the peak of the gel permeation chromatograph of the resorcin formalin resin itself.

In the present invention, by partially improving the manufacturing process, the concentration of calcium chloride contained in the final resin product is greatly reduced. The analysis results comparing the concentration of calcium chloride contained in [Example 2] in the MEK-modified resorcin formalin resin before improvement [Comparative Example 2] and the MEK-modified resorcin formalin resin after improvement are shown in [Table 1].

［表１］に示す通り、製造工程中の処理方法変更および水洗処理回数によるＭＥＫ変性レゾルシンホルマリン樹脂中の塩化カルシウム濃度の低減効果は、かなり大きい。

As shown in [Table 1], the effect of reducing the calcium chloride concentration in the MEK-modified resorcin formalin resin by changing the treatment method during the manufacturing process and the number of water washing treatments is quite large.

The analysis method adopted is as follows.

The amount of calcium in the MEK-modified resorcin formalin resin was quantified by low-temperature ashing / acid decomposition-ICP method.

As a result of examining the method for recovering methanol, the reaction solution was allowed to stand, the MEK layer and the aqueous layer were separated, the aqueous layer (0) was extracted, and ammonia water or the like was added thereto to adjust the pH to 6 to 10. Thereafter, methanol can be efficiently recovered by distillation. It is also contained in the water layer (1), the water layer (2) and the MEK layer (2) after washing with water, and these can be obtained mainly by rectifying the fraction at the initial stage of distillation.
The methanol recovered by this method can be used for equipment cleaning solvents, fuels, etc., and by removing the methanol, the aqueous layer containing calcium chloride can be reused.

Calcium chloride can be recovered from the aqueous layer from which methanol has been removed by distillation, by decompression, azeotropic dehydration, or the like. In addition to this recovery method, calcium chloride can be reused by the above recycling method. That is, since the concentration of calcium chloride in the solution before the reaction is 39% by mass and decreases to 36% by mass after the reaction, calcium chloride corresponding to the reduced concentration is added later, or water is simply distilled. It is possible to use a so-called closed system recycling in which the solution is removed by the method and the calcium chloride concentration of the solution is adjusted to 39% by mass to return to the system before the reaction.

About MEK, the MEK layer (2) separated from the water layer in the production process can be separated and recovered by simple distillation and rectification. In addition, it can be recovered by simple distillation from the separated aqueous layer and purifying the initial fraction.
The recovered high-purity MEK can be returned to the reaction system and reused as a part of the raw material.

In the current method, in the process of producing a MEK-modified resorcin formalin resin, the reaction is allowed to stand after completion of the reaction and separated into an MEK layer and an aqueous layer containing calcium chloride and the like. In order to remove calcium chloride dissolved in a small amount of water contained in the MEK layer, the calcium chloride deposited by azeotropic dehydration of the MEK layer was removed by pressure filtration, but this method is complicated. It took a long time and the removal effect was insufficient. Therefore, by changing the process to a method of washing the MEK layer with water (implemented twice or more), the calcium chloride concentration in the final product, MEK-modified resorcin formalin resin, can be reliably reduced to 100 ppm or less. stable product quality of the force or the like is to be able to manufacture.

Since the aqueous layer (0) in the above production process contains a large amount of raw materials such as calcium chloride, methanol and hydrochloric acid, it is a highly acidic waste liquid. In the present invention, in order to adjust the calcium chloride concentration in the liquid, it is necessary to neutralize hydrochloric acid with ammonia or the like as a distillation condition to suppress the influence of hydrochloric acid. The degree of liquidity of the aqueous layer (0) used for distillation is adjusted to pH = 4 to 10, more preferably pH = 6 to 9, and then water and methanol are distilled by vacuum distillation after pH adjustment with ammonia water or the like. Leave. The distilled methanol water is used for cleaning the apparatus.

Calcium chloride can be reused by the recycling method described above from the aqueous layer (0) from which methanol has been removed by distillation. That is, the calcium chloride concentration in the reaction system is adjusted to 39% by mass at the time of reuse, and then the so-called calcium chloride closed system recycling can be used.

The water layer (1) washed once with water contains MEK, methanol, a small amount of calcium chloride, and the like, and a high purity MEK is obtained by rectifying the fraction from which the initial fraction has been removed. Can do. The removed initial fraction mainly contains MEK and methanol, and can be separated and recovered by rectifying this.

MEK and methanol are contained in the aqueous layer (2), and there is no need for pH adjustment with aqueous ammonia. MEK and methanol are removed by rectifying a fraction obtained by distillation under reduced pressure and removing the initial fraction. Separation and recovery are possible. The aqueous layer after methanol recovery can be discarded as it is.

MEK is simply distilled at the stage of water solvent replacement of the MEK layer (2) during the production process. Since it contains water, it can be separated and recovered by further rectification. In addition, the separated water layer (1) and water layer (2) can be recovered by distillation and further rectification. The recovered high-purity MEK can be returned to the reaction system and reused as a part of the raw material. The liquid temperature is equal to or lower than the azeotropic temperature of MEK-water, and the distillation apparatus may be a distillation apparatus without a packed tower. Further, the rectification apparatus is also a general one (the number of theoretical plates is 5 to 10) and can be separated.

By improving the manufacturing process of MEK-modified resorcin formalin resin, the calcium chloride concentration in the final product, MEK-modified resorcin formalin resin, can be reliably reduced to 100 ppm or less, and products with stable quality including adhesive strength can be manufactured. It became so.

That is, in the present invention, since the specific raw materials (calcium chloride, MEK) used and methanol contained in formalin can be separated and recovered and reused, the raw material cost is also reduced. Further, by partially improving the production process, the calcium chloride concentration in the product MEK-modified resorcin formalin resin can be reduced to 100 ppm or less, and a product that is stable in quality can be produced. .

Hereinafter, the present invention will be described in detail with reference to examples.

After adding 270 kg of water, 170 kg of calcium chloride and 74 kg of resorcin in an acid-resistant 500 liter reaction tank and dissolving them at 50 ° C., 30 kg of MEK and 0.9 kg of 35% hydrochloric acid were placed in the reaction tank. While maintaining the reaction system at 50 ° C., 33 kg of 37% formalin was added dropwise over 30 minutes, and after completion of the addition, the mixture was further stirred for 30 minutes to proceed a liquid-liquid heterogeneous reaction. While maintaining the temperature of the reaction system, the mixture was left to separate into two layers, and the aqueous layer (0) was extracted. Add 100 kg of water to the MEK layer (0) and wash thoroughly. The aqueous layer (1) was extracted by allowing to stand and separating into two layers. This water washing operation was further performed once or more to remove the water layer (2), and a MEK solution containing MEK-modified resorcin formalin resin was obtained in the MEK layer (2).

The MEK solution of resorcin formalin resin obtained in [Example 1] is put into the reaction vessel again, 80 kg of water is added, 0.6 kg of 28% ammonia water is added, and distillation is performed at an azeotropic temperature, and then MEK is distilled. The water content was reduced to obtain a resorcin formalin resin aqueous solution having an appropriate fluidity with a target solid content of about 50%. This aqueous solution of resorcin formalin having a solid content of about 50% does not contain an inorganic salt, and is a MEK-modified resorcin formalin resin in which the contents of resorcin monomer and resorcin pentanuclear are reduced.

The MEK-modified resorcin formalin resin obtained in [Example 2] was dissolved in tetrahydrofuran, gel permeation chromatography analysis was performed, and the distribution of unreacted resorcin to resorcin pentanuclear or higher was measured. The results are shown in FIG. Next, the peak area ratio of the obtained chromatogram was shown.
Resorcinol ――――― 6.5%
Resorcin dinuclear body 13.4%
Resorcin trinuclear body ----- 14.3%
Resorcin tetranuclear ----- 13.5%
Resorcin 5 nuclei or more-- 52.3%

The gel permeation chromatography analysis conditions at this time are shown below.
Measurement model: Tosoh HLC-8020
Column: (G-2000) + (G-2000) + (G-4000)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 1 ml / min

[Comparative Example 1]
270 kg of water, 170 kg of calcium chloride, and 74 kg of resorcin were placed in an acid-resistant 500 liter reaction tank, dissolved at 50 ° C., and then 30 kg of MEK and 0.9 kg of 35% hydrochloric acid were placed in the reaction tank. While maintaining the reaction system at 50 ° C., 33 kg of 37% formalin was added dropwise over 30 minutes, and after completion of the addition, the mixture was further stirred for 30 minutes to proceed a liquid-liquid heterogeneous reaction. While maintaining the temperature of the reaction system, the mixture was left to separate into two layers, and the aqueous layer (0) was extracted. The MEK layer (0) was diluted with 200 kg of MEK, 100 kg of water was added, the reaction system was further stirred for 30 minutes while maintaining the same temperature, allowed to stand, separated into two layers, and the aqueous layer (1) was extracted. . The MEK layer (1) was again diluted with 400 kg of MEK, and dehydrated by distillation at the azeotropic temperature of water and MEK. Next, after cooling to room temperature, solid calcium chloride was removed by filtration to obtain a MEK solution containing MEK-modified resorcin formalin resin.

[Comparative Example 2]
The MEK solution of resorcin formalin resin obtained in [Comparative Example 1] is put into the reaction vessel again, 200 kg of water is added, 0.6 kg of 28% ammonia water is added, and distillation is performed at an azeotropic temperature, and MEK is then added. The water content was reduced to obtain a resorcin formalin resin aqueous solution having an appropriate fluidity with a target solid content of about 50%. The aqueous solution of resorcin formalin having a solid content of about 50% is a MEK-modified resorcin formalin resin with a reduced content of resorcin monomer and resorcin pentanuclear.

[Comparative Example 3]
The MEK-modified resorcin formalin resin obtained in [Comparative Example 2] was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis to measure the distribution of unreacted resorcin to resorcin pentanuclear or higher. The results are shown in FIG. Next, the peak area ratio of the obtained chromatogram was shown.
Resorcinol ――――― 6.6%
Resorcin dinuclear body --------------------- 13.3%
Resorcin trinuclear body ---- 14.0%
Resorcin tetranuclear ---- 13.2%
More than 5 resorcinol nuclei-- 52.9%

The method of removing methanol from the aqueous layer (0) obtained in the production process of [Example 1] is as follows.
That is, after the liquid-liquid heterogeneous reaction between MEK and water has progressed, the reaction system is allowed to stand while maintaining the temperature of the reaction system and separated into two layers, and the aqueous layer (0) is moved to the distillation kettle (1000 L). To do. To this aqueous layer (0), 28% aqueous ammonia is added to neutralize the pH of the aqueous solution to 7-8. Thereafter, methanol in the aqueous solution is distilled off by a distillation method (liquid temperature: around 65 to 70 ° C.). This recovered methanol is transferred to the mixing container including methanol recovered from the aqueous layer (1), the aqueous layer (2), etc., and can be reused mainly for equipment cleaning.

An acid-resistant 500 liter reaction vessel was charged with 436 kg of an aqueous solution in which the concentration of calcium chloride contained in the aqueous layer obtained by removing methanol obtained in [Example 4] was adjusted to 39% by mass and 74 kg of resorcin, at 50 ° C. After dissolution, 30 kg of recovered MEK and 0.9 kg of 35% hydrochloric acid were placed in the reaction vessel. While maintaining the reaction system at 50 ° C., 33 kg of 37% formalin was added dropwise over 30 minutes, and after completion of the addition, the mixture was further stirred for 30 minutes to proceed a liquid-liquid heterogeneous reaction. While maintaining the temperature of the reaction system, the mixture was left to separate into two layers, and the aqueous layer (0) was extracted. Add 100 kg of water to the MEK layer (0) and wash thoroughly. The aqueous layer (1) was extracted by allowing to stand and separating into two layers. This water washing operation was further performed once or more to remove the water layer (2), and a MEK solution containing MEK-modified resorcin formalin resin was obtained in the MEK layer (2).

The MEK solution of resorcin formalin resin obtained in [Example 5] is put into the reaction vessel again, 80 kg of water is added, 0.6 kg of 28% ammonia water is added, and distillation is performed at the azeotropic temperature, and then MEK is distilled. The water content was reduced to obtain a resorcin formalin resin aqueous solution having an appropriate fluidity with a target solid content of about 50%. This aqueous solution of resorcin formalin having a solid content of about 50% does not contain an inorganic salt, and is a MEK-modified resorcin formalin resin in which the contents of resorcin monomer and resorcin pentanuclear are reduced.

The MEK-modified resorcin formalin resin obtained in [Example 6] was dissolved in tetrahydrofuran, gel permeation chromatography analysis was performed, and the distribution of unreacted resorcin to resorcin pentanuclear was measured. The results are shown in FIG. Next, the peak area ratio of the obtained chromatogram was shown.
Resorcinol ―――――― 6.9%
Resorcin dinuclear body 13.6%
Resorcin trinuclear body ----- 14.2%
Resorcin tetranuclear ---- 13.2%
Resorcin 5 nuclei or more-- 52.1%

The peak area ratio of the chromatogram obtained with the MEK-modified resorcin formalin resin synthesized using the recovered raw material (MEK, calcium chloride water) of [Example 6] and the MEK-modified resorcin formalin resin synthesized without using the recovered raw material [ When the peak area ratio of the gel permeation chromatogram of Example 2] is compared and examined, no difference is observed between the two. In addition, similar results were obtained in other quality tests, and it was confirmed that there was no problem in quality when using the recovered material.

As a model experiment (1), a MEK-modified resorcin formalin resin was synthesized under the same production conditions as in [Example 1], and an aqueous layer (0), an aqueous layer ( The amount of methanol and the amount of MEK contained in each of 1), the aqueous layer (2) and the MEK layer (2) were quantified by GC (gas chromatography) method. The amount of methanol contained in the raw material formalin was 8.1 V / V%. The analysis results are shown in [Table 2].

Moreover, from the respective obtained amounts, specific gravity thereof, and analysis results of [Table 2], the amounts of methanol and MEK in each sample are shown in [Table 3].

Table 3 shows the amount of methanol in each sample (No. 1 to No. 4). This is to quantify the amount of methanol contained in each sample using the following calibration curve. From these results, the distribution ratio to each sample is generally the value shown in [Table 3], as originally predicted. It was a result.

The methanol and MEK contents in each sample were quantified under the following GC conditions.

[GC condition]
Model: Agilent Technologies 6890N, Autoinjector 7683ALS
Column: fused silica HP-1, 0.25 mmφ × 30 m (film thickness 0.25 μm)
Detector: Hydrogen flame ionization detector, Hydrogen flow rate: 30 ml / min,
Air flow rate: 400 ml / min,
Column temperature: 60 ° C. (holding time 4 minutes), 50 ° C./min temperature increase, 160 ° C. (holding time 5 minutes)
Inlet temperature: 200 ° C, Detector temperature: 220 ° C,
Carrier gas: helium, column flow rate: 26 cm / sec (1.0 ml / min)
Split ratio: 20: 1
Septum purge: 3-6 ml / min, Make-up gas: nitrogen, 25 ml / min
Injection volume: 1 μl, analysis time: 4 min,

[Making calibration curves for methanol and MEK]
The method for creating a calibration curve is as follows.
(1) For the calibration curve of methanol, 5 ml of methanol was collected in a 100 ml volumetric flask, and the volume was fixed with water to prepare a 5% (V / V) solution. This solution was diluted with water to prepare 0.05, 0.1, 0.2, and 0.5% (V / V) calibration curve solutions, which were measured under the above GC conditions to obtain peak heights ( A calibration curve between Y) and concentration (X) was prepared.
(2) Similarly, MEK calibration curves were prepared using 0.2, 0.5, 1.0, and 3.0% (V / V) solutions.
The regression equation of the obtained calibration curve is as follows.

[Methanol and MEK calibration curve]
(1) Methanol:
Regression formula: Y = 694.5622Х-1.5038 (correlation coefficient r = 0.9991)
(2) MEK:
Regression formula: Y = 2052.7238X + 9.2004 (correlation coefficient r = 0.998)

Next, as a model experiment (2), in order to verify the influence of the amount of methanol contained in the reaction solution, the reaction was carried out by adding a certain amount of methanol to the production conditions with the same charge ratio as [Example 1]. . Each of the obtained MEK-modified resorcin formalin resins was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis under the previous analysis conditions, and the distribution of unreacted resorcin (monomer body) to resorcin pentanuclear body was measured. The peak area% (PA%) of the obtained chromatogram is shown in [Table 4].

From the results of [Table 4], when the amount of methanol in the reaction solution increases, a part of the tetranuclear from the dinuclear in the RF resin moves to the aqueous layer, and as a result, the number of pentanuclear or more tends to increase. Admitted. From this analysis result, it was confirmed that when the amount of methanol was 10% or more in the reaction solution, it deviated from the specified quality value (a ratio of 5 nuclei or more in the RF resin).

The present invention is a method for producing a MEK-modified resorcin formalin resin characterized in that recovery and reuse of methanol contained in a specific raw material (calcium chloride, MEK) and formalin is performed in parallel. By stabilizing, reducing costs, and reducing the burden on the environment, it can be applied to the production of polymers using similar formalins.

3 is a gel permeation chromatograph of the MEK resorcin formalin resin aqueous solution obtained in Example 2. FIG. 6 is a gel permeation chromatograph of an aqueous MEK resorcin formalin resin solution obtained in Comparative Example 2. FIG. 6 is a gel permeation chromatograph of the MEK resorcin formalin resin aqueous solution obtained in Example 6. FIG.

Claims (4)

  (A) 20-40 parts by mass of resorcin is added to 100 parts by mass of an aqueous solvent, (B) 20-80 parts by mass of calcium chloride is added to 100 parts by mass of water, and (C) methyl ethyl ketone (hereinafter, MEK). (A) is added to 10 to 100 parts by mass with respect to 100 parts by mass of resorcin, and the mixture is stirred to form a two-phase system in which no solids remain, and (D) hydrochloric acid as a catalyst is added, and (E) 1 -40% formalin was added dropwise with stirring in an amount such that formaldehyde / resorcin = 0.3-0.7 mol ratio to (A) resorcin, and the liquid-liquid heterogeneous reaction was allowed to proceed, and left to stand. After separating the aqueous layer (0), water is added to the MEK layer (0), which is the reaction product layer after removal of the aqueous layer (0), in an amount equivalent to 5 times the amount of the reaction product, washed with water, and allowed to stand. The two layers are separated, the aqueous layer (1) is removed, and this washing operation is further performed. At least once, the aqueous layer (2) is removed to obtain the MEK layer (2) containing the MEK-modified resorcin formalin resin, and 2.5 to 5 times the amount of water is added to the MEK layer by mass. 1 to 30% aqueous ammonia is added and distilled, and (C) MEK is removed by distillation to finally have a moderate fluidity of a reaction product concentration of 30 to 80% and pH of 6 to 10, The calcium chloride concentration is 100 ppm or less, and the peak area corresponding to the resorcin monomer is 3 to 9% of the total peak area obtained by gel permeation chromatography analysis, which corresponds to the resorcin pentanuclear or more. To obtain a MEK-modified resorcin formalin resin aqueous solution having a peak area of 30 to 55%, which is contained in the specific raw materials (calcium chloride, MEK) and (E) formalin in the manufacturing process described above. A method for producing a MEK-modified resorcin formalin resin, characterized in that the recovery and reuse of methanol is performed in parallel. However, the numerical value in () represents the processing order. The above-mentioned (E) 1-40% methanol contained in formalin methanol layer (0), water layer (1), water layer (2), and MEK layer (in the MEK-modified resorcin formalin resin manufacturing process described above ( The method for producing a MEK-modified resorcin formalin resin according to claim 1, wherein methanol is recovered and reused in parallel by distillation under reduced pressure from 2) and further rectification.   After removing methanol from the aqueous layer (0) in the process of producing the MEK-modified resorcin formalin resin, the concentration of calcium chloride contained in the aqueous layer is controlled to the concentration at the start of the reaction, so that The method for producing a MEK-modified resorcin formalin resin according to claim 1, wherein the reuse is performed in parallel as calcium).   The MEK layer (2), the water layer (1), and the water layer (2) in the MEK-modified resorcin formalin resin production process are simply distilled from the water layer and further rectified to recover and reuse the specific raw material (MEK). The method for producing a MEK-modified resorcin formalin resin according to claim 1, wherein the steps are performed in parallel.

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