JP2003002941A - Method for producing novolak-type phenolic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a novolak-type phenolic resin, capable of efficiently producing the resin in a high yield which scarcely contains unreacted phenols, though a process for removing the unreacted phenols is partially or completely eliminated by increasing a reaction rate. SOLUTION: This method for producing the novolak-type phenolic resin comprises reacting phenols with aldehydes by using an organic phosphonic acid, wherein an alkaline substance is added to the reaction mixture after the completion of the reaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing a novolak type phenol resin containing a small amount of unreacted phenols in a high yield. The novolac type phenolic resin obtained in the present invention is preferably used as a binder for a molding material, a friction material, a grindstone, a sealing material and the like.

[0002]

2. Description of the Related Art Novolak type phenolic resins are prepared by reacting phenols and aldehydes with inorganic or organic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, oxalic acid or p-toluenesulfonic acid as catalysts. Can be obtained at. However, the novolak type phenolic resins reacted with these catalysts have a reaction rate of 60 to 90% with respect to the total amount of the phenols charged, when the binuclear or more phenolic compounds are regarded as the resin. It was difficult to obtain a reaction rate higher than this. Therefore, in order to further reduce the amount of unreacted components in the reaction product, 150 to 250 ° C.
It is necessary to remove unreacted phenol by performing vacuum distillation and steam distillation at such a high temperature. In addition, since 10% or more of unreacted phenols are usually removed, there is a problem in that the yield is reduced.

In recent years, there has been a demand for reducing the amount of unreacted phenols contained in novolac type phenolic resins due to the necessity of environmental protection, and among them, there is a demand for novolac type phenolic resins in which the amount of unreacted phenols is 1% or less. However, in order to achieve this, it is necessary to remove more unreacted phenols by raising the temperature and vacuum degree in the step of removing unreacted phenols by vacuum distillation or steam distillation. Therefore, there is a problem that more energy and man-hours are required and the cost is increased.

[0004]

DISCLOSURE OF THE INVENTION The present invention has a high yield of a novolac type phenol resin having a small amount of unreacted phenols even if the step of removing unreacted phenols is reduced or eliminated by increasing the reaction rate to the resin. The present invention provides a manufacturing method that can be efficiently obtained at a high rate.

[0005]

The present invention relates to (1) a method for producing a novolak type phenol resin by reacting a phenol and an aldehyde with an organic phosphonic acid, which comprises a phenol and an aldehyde. A method for producing a novolak type phenolic resin, characterized in that an alkaline substance is added after the reaction with (2) the pH of the novolak type phenolic resin becomes 4 to 10 due to the addition of the alkaline substance. Of producing type phenolic resin. (3) The reaction molar ratio (F / P) of the aldehydes (F) to the phenols (P) is 0.5 to 0.9.
5. Organic phosphonic acid was added in an amount of 0.
001-0.1 mol and the manufacturing method of the novolak type phenol resin as described in (1) or (2), (4).
Any of paragraphs (1) to (3), wherein the amount of water in the reaction system when reacting phenols and aldehydes with an organic phosphonic acid as a catalyst is 20% by weight or less and the reaction temperature is 100 to 200 ° C. The method for producing a novolac type phenolic resin according to (1), wherein (5) the organic phosphonic acid is represented by the general formula (I): (1) to (4)
Item 10. The method for producing a novolac type phenolic resin according to any one of items 1 to 5, R-PO (OH) ₂ (I) (wherein R contains a carbon atom, and -COOH and / or-
It is a group containing PO (OH) ₂ .

The phenols used in the present invention are not particularly limited, but phenols such as phenol, orthocresol, metacresol, paracresol, xylenol, paratertiary butylphenol, paraoctylphenol, paraphenylphenol, bisphenol A, bisphenol F, resorcinol, etc. Examples include at least one or more phenols selected from the group, and usually phenol and cresol are often used.

The aldehyde used in the present invention is not particularly limited, but it is formaldehyde, acetaldehyde, butyraldehyde, acrolein, etc. or a mixture thereof, and a substance which is a source of generation of these aldehydes or a solution of these aldehydes is used. It is also possible to do so, and at least one or more aldehydes selected from these aldehydes can be mentioned, but usually formaldehyde is often used.

Phenols (P) and aldehydes (F)
The molar ratio (F / P) charged with is not particularly limited, but is preferably 0.5 to 0.95, and more preferably 0.7 to 0.9. If the molar ratio is less than the lower limit, unreacted phenols may remain unreacted and the reaction rate to the resin may not increase, and if it exceeds the upper limit, gelation may occur depending on the reaction conditions. Become. Further, when the phenols and the aldehydes are reacted, at the start of the reaction, all the phenols and the aldehydes are reacted in a batch with the charged catalyst,
Further, in order to suppress heat generation at the initial stage of the reaction, the phenols and the catalyst may be mixed and then the aldehydes may be sequentially added and reacted.

The organic phosphonic acid used as a catalyst in the present invention is an organic compound containing a phosphonic acid group —PO (OH) ₂ , and any of them can be used, but the phosphonic acid represented by the general formula (I) is used. However, it is preferable to obtain a novolac type phenol resin efficiently with a high yield with less unreacted phenols. R-PO (OH) ₂ (I) (R contains a carbon atom, and-COOH and / or-
Examples of the organic phosphonic acid represented by the general formula (I) include ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, β, which is a group containing PO (OH) _2. -Aminoethylphosphonic acid-N, N-diacetic acid, aminomethylphosphonic acid-N, N-diacetic acid, 1-hydroxyethylidene-1,1'-diphosphonic acid, 2-phosphonobutane-
1,2,4-tricarboxylic acid and the like. Among these, aminotrismethylenephosphonic acid, 1-hydroxyethylidene-1,1′-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid, which are industrially mass-produced and inexpensive in view of the purpose of the present invention. Is preferred.

The amount of the organic phosphonic acid added is not particularly limited, but it is 0.00 per 1 mol of phenols.
The amount is preferably 1 to 0.1 mol, and more preferably 0.003 to 0.05 mol. The greater the amount of the organic phosphonic acid added, the greater the effect of the present invention that the unreacted phenols are less and the phenol resin can be obtained in a high yield. However, when the amount of the catalyst added exceeds the above upper limit, the novolac-type phenol resin is produced. Since the amount of residual organic phosphonic acid increases, the residual salt produced when an alkaline substance is added to this may affect the curability of the phenol resin. On the other hand, if the amount is less than the lower limit, the effect as a catalyst tends not to be sufficiently exhibited. In addition to the above-mentioned organic phosphonic acid as a catalyst, an acid such as oxalic acid, sulfuric acid, hydrochloric acid, p-toluenesulfonic acid or the like which is usually used in the production of novolac type phenolic resin can be used together within a range not impairing the object of the present invention. These acids have the effect of promoting the reaction in the polymer region.

In the present invention, the reaction conditions for reacting phenols and aldehydes with an organic phosphonic acid as a catalyst are not particularly limited, but in order to efficiently obtain a novolac type phenol resin containing a small amount of unreacted phenols. , The water content in the reaction system is 2 with respect to the total weight of the reaction system.
It is preferably 0% by weight or less.

In the present invention, the amount of water in the reaction system is the total amount of the amount of water in the charged raw materials and the amount of condensed water produced by the reaction, and in the case of reacting while removing water by distillation, The water content is obtained by subtracting the distilled water content from the total amount. The smaller the amount of water in this reaction system, the higher the effect of reducing unreacted phenols by increasing the reaction rate of the raw materials to the resin, but when the amount is too small, the organic phosphonic acid becomes highly viscous or solidifies, Since the catalytic action may be lowered, it is preferable that the water content be such that water of crystallization can be contained. When the water content exceeds 20% by weight, the effect is almost unchanged. More preferably, it is 0.5 to 15% by weight.

Although the reaction temperature is not particularly limited, it is preferably 100 to 200 ° C. 100 ° C
When it is lower, the organic phosphonic acid which is a catalyst has higher viscosity or is solidified under the condition of low water content as described above, and the catalytic action is apt to be lowered. If the temperature exceeds 200 ° C, decomposition of organic phosphonic acid and decomposition of novolac type phenol resin may occur. Decomposition of the organic phosphonic acid and the novolac type phenol resin is more preferable because it is less likely to occur at a low temperature, but, for example, when the reaction is performed under the condition that the water content is 0.5 to 15% by weight, the organic phosphonic acid has a high viscosity. The temperature range for achieving a sufficient catalytic action without solidification or solidification is more preferably 1
It is 00-160 degreeC.

These conditions are more effective when applied in the latter stage of the reaction of phenols and aldehydes, but are not particularly limited. In the case of the sequential addition reaction of aldehydes, the latter term of the reaction here means that phenols 1
It is the reaction after the step in which the aldehydes exceed 0.4 mol per mol, and when the phenols and the aldehydes are collectively charged and reacted, the unreacted aldehydes in the reaction system are This is a reaction in a later step than the time when it is considered that 0.4 mol of aldehydes are reacted with 1 mol of phenols.

When this reaction is carried out under normal pressure, the water content becomes 2
In the range of 0% by weight or less, the reflux temperature is almost 100 to 200 ° C.
At this time, the atmospheric pressure reaction is a preferable condition for controlling the temperature and the water content. Other reaction conditions may include solvent reflux dehydration reaction using a non-aqueous solvent such as butanol and propanol, and high pressure reaction. Further, a reaction which proceeds while removing generated condensation water by distillation or the like while adding aldehydes is a preferable condition because the amount of water in the reaction system becomes constant. In this case, since unreacted phenols may be easily removed together with water, the unreacted phenols are reacted so that the unreacted phenols are not distilled until the unreacted phenols fall below a certain amount. After or after removing water by distillation, the reaction can be continued by setting the amount of water in the reaction system at 20% by weight or less and the reaction temperature at 100 to 200 ° C.

Water is generally and preferably used as the reaction solvent, but an organic solvent may be used, and a non-polar solvent may be used to carry out the reaction in a non-aqueous system. Alternatively, paraform or the like may be used without a reaction solvent. As the organic solvent, alcohols, ketones, aromatics and the like can be used. As alcohols, methanol, ethanol,
Propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, etc.
Examples of ketones include acetone and methyl ethyl ketone.
Examples of aromatics include toluene and xylene.

In addition to the above, a suspension stabilizer and a water-soluble neutral salt may be added. Since the reaction in the present invention is a heterogeneous reaction in which the catalyst phase is finely dispersed in the phenols or novolac type phenolic resin, the water-soluble neutral salt has the effect of clarifying the phase separation state, The stabilizer has the function of promoting fine dispersion. Further, since this reaction is a heterogeneous reaction, it is desirable that the stirring conditions at the time of the reaction are high-speed stirring, but it is not particularly limited.

Next, the present invention is characterized by reacting phenols and aldehydes in the presence of an organic phosphonic acid, and then adding an alkaline substance. This alkaline substance is not particularly limited, but includes alkali metal hydroxides such as lithium, sodium and potassium, and alkaline earth metal hydroxides and oxides such as magnesium, calcium and barium, amines, amines such as ammonia, and the like. At least one kind of alkaline substance selected from other alkali catalysts can be mentioned, and they can be used alone or in combination. Usually, calcium hydroxide, sodium hydroxide and ammonia are often used.

The amount of the alkaline substance added is not particularly limited, but it is preferable that the addition amount is within the range where the pH of the novolac type phenol resin after addition is from 4 to 10. More preferably, it is 5-8. When the pH is below the lower limit, decomposition of the novolac type phenol resin by heat tends to occur when the novolac type phenol resin is brought into a molten state. When the pH exceeds the upper limit, the curability of the novolac type phenol resin may be affected. In addition, the novolac-type phenol resin is decomposed by heat when it is kept at a high temperature of 150 ° C. or higher for a long time without addition of an alkaline substance after the reaction of phenols and aldehydes is completed, and the amount of phenols increases. Since an increase in molecular weight can occur,
It is desirable to add the alkaline substance promptly after the reaction between the phenols and the aldehydes is completed. In the present invention, the method for measuring the pH is not particularly limited, but as an example, the resin after addition of the alkaline substance is diluted with the same volume of methanol, and further diluted with twice the volume of pure water of the resin. There is a method in which a sample obtained by diluting, stirring sufficiently, and uniformly dispersing the sample is measured using a pH meter.

After completion of the reaction, if necessary, water, an organic solvent,
Furthermore, in order to remove unreacted phenols, atmospheric distillation, reduced pressure distillation, steam distillation and the like can be performed. These steps are usually performed at a temperature of 150 ° C. or higher at which the novolac type phenol resin is melted, and therefore it is preferable to perform these steps after the addition of the alkaline substance.

The novolac type phenolic resin of the present invention is
When used as a binder for a molding material, a friction material, a grindstone, a sealing material, etc., a curing agent is usually used and can be cured by heating or the like. Examples of the curing agent include hexamethylenetetramine, epoxy resin, resole resin, and aldehydes, but are not particularly limited. When used as a binder, organic or inorganic filler,
Other resins may be mixed and used.

In the present invention, the reason why a novolac type phenol resin containing a small amount of unreacted phenols can be efficiently obtained in a high yield by using an organic phosphonic acid as a catalyst and increasing the reaction rate to the resin is as follows. Is thought to be. The organic phosphonic acid used in the present invention is very water-soluble and easily hydrated. The phenols have a low solubility, and the novolac type phenolic resins have a property that the solubility becomes smaller as the molecular weight increases. Therefore, at the time of reaction, an aqueous phase containing a large amount of aldehydes and a catalyst organic phosphonic acid, phenols,
It is in a state of being phase-separated into an organic phase composed of a novolac-type phenol resin and having almost no catalyst. Phenols are relatively easy to elute in the aqueous phase, and the eluted portion reacts with aldehydes. However, when the reaction becomes a binuclear or more, elution becomes slow and the reaction becomes difficult to proceed. In this way, a reaction rate difference between the low molecular weight region and the high molecular weight region occurs, so by increasing the reaction rate to the resin, it is possible to efficiently obtain a novolac type phenol resin with a small amount of unreacted phenols in a high yield. It will be possible.

In the present invention, an organic phosphonic acid is used as a catalyst, and the reaction conditions are preferably such that the amount of water in the reaction system is 20% by weight or less and the reaction temperature is 100 to 200 ° C.
By this, there is an effect of further increasing the reaction rate of phenols to the resin by the production method of the present invention. The reason is considered as follows. The reaction temperature is 100 to 20
By setting the temperature to 0 ° C., phenols in the organic phase are easily eluted into the aqueous phase, and the reaction in the aqueous phase easily proceeds. Then, the water content is kept low and the ion concentration in the water phase is kept high. Therefore, the acidity of the aqueous phase is high and the reaction easily proceeds, and the interface between the aqueous phase and the organic phase is more clearly separated, so that the reaction on the organic phase side is difficult to proceed. Further, the organic phosphonic acid has the property of increasing the viscosity and solidifying at a high concentration, but it can be prevented from becoming a molten state and losing the catalytic function at a high temperature. From these effects, the reaction rate of the phenols with the resin is increased, and the effect of efficiently obtaining the resin with a small amount of unreacted phenols in a high yield is increased.

The reason why the alkaline substance is added in the present invention is considered as follows. The novolak type phenol resin undergoes a decomposition reaction called rearrangement reaction as the temperature increases under acidic conditions. As a result, the molecular weight of the novolac type phenol resin increases and the amount of phenolic monomer increases. This can be prevented by adding an appropriate amount of alkaline substance.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples. All "parts" and "%" described herein indicate "parts by weight" and "% by weight".

Example 1 In a 3 L three-necked flask, 1000 parts of phenol, 1-hydroxyethylidene-1,
60% aqueous solution of 1'-diphosphonic acid (ferriox 11
No. 5, manufactured by Lion Co., Ltd.) was added, the temperature was raised to 120 ° C., and 225 parts of 92% paraformaldehyde was sequentially added under reflux for 90 minutes for reaction. At the end of the reaction, the water content in the reaction system was 12%. Then, atmospheric distillation is performed, and
The temperature was raised to 0 ° C. so that the water content was 2%. Under atmospheric pressure distillation reaction at 140 ° C., 90 parts of 92% paraformaldehyde was added for 60 minutes for reaction. After completion of the reaction, a reflux reaction was carried out for 30 minutes. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, a liquid obtained by mixing 9.7 parts of calcium hydroxide and 20 parts of water was slowly added. Then, atmospheric distillation was performed, the temperature was raised to 150 ° C., vacuum distillation was performed at a reduced pressure of 5000 Pa, and the temperature was raised to 150 ° C. to obtain 1102 parts of novolac type phenol resin A.

Example 2 1000 parts of phenol and 1-hydroxyethylidene-1, in a 3 L three-necked flask,
60% aqueous solution of 1'-diphosphonic acid (ferriox 11
5, 100 parts of Lion Co., Ltd.) was added, the temperature was raised to 120 ° C., and 225 parts of 92% paraformaldehyde was successively added for 90 minutes under reflux condition to react. At the end of the reaction, the water content in the reaction system was 14%. Then, atmospheric distillation was performed and the temperature was raised to 140 ° C. to make the water content 3%.
Under atmospheric pressure distillation reaction at 140 ° C., 92 parts of 92% paraformaldehyde was added thereto for 60 minutes, and the reaction was carried out while being added. After completion of the reaction, a reflux reaction was carried out for 30 minutes. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, 70 parts of 50% sodium hydroxide aqueous solution was slowly added. Then, atmospheric distillation was performed, the temperature was raised to 150 ° C., vacuum distillation was performed at a reduced pressure of 5000 Pa, and the temperature was raised to 150 ° C. to obtain 1124 parts of novolac type phenol resin B.

Example 3 In a 3 L three-necked flask, 1000 parts of phenol and 1-hydroxyethylidene-1,
60% aqueous solution of 1'-diphosphonic acid (ferriox 11
No. 5, manufactured by Lion Co., Ltd.) was added, the temperature was raised to 120 ° C., and 225 parts of 92% paraformaldehyde was successively added for 90 minutes under reflux condition to react. At the end of the reaction,
The water content in the reaction system was 12%. Then, atmospheric distillation was performed and the temperature was raised to 140 ° C. to make the water content 2%. 14
92% paraformaldehyde 69 under atmospheric distillation at 0 ° C
The reaction was carried out for 60 minutes while partwise added. After completion of the reaction, a reflux reaction was carried out for 30 minutes. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, 26 parts of triethanolamine was slowly added. Then, atmospheric distillation is performed, the temperature is raised to 150 ° C., and vacuum distillation is performed at a reduced pressure of 5000 Pa to obtain 1
Raise the temperature to 50 ° C and add 1 to the novolac type phenolic resin C.
I got 108 copies.

Example 4 In a 3 L three-necked flask, 1000 parts of phenol, 1-hydroxyethylidene-1,
60% aqueous solution of 1'-diphosphonic acid (ferriox 11
5, 100 parts of Lion Co., Ltd.) was added, the temperature was raised to 100 ° C., and 690 parts of 37% aqueous formaldehyde solution were successively added for 30 minutes under reflux condition to react. At the end of the reaction, the water content in the reaction system was 35%. 3 after reaction
A reflux reaction was carried out for 0 minutes. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, a liquid obtained by mixing 32.5 parts of calcium hydroxide and 70 parts of water was slowly added. Then, atmospheric distillation was performed, the temperature was raised to 150 ° C., vacuum distillation was performed at a reduced pressure of 5000 Pa, and the temperature was raised to 220 ° C., and 1121 parts of novolac type phenol resin D was obtained.

Example 5 In a 3 L three-necked flask, 1000 parts of phenol and 120 parts of 50% aminotrismethylenephosphonic acid aqueous solution (Dequest 2000, manufactured by Solusia Japan KK) were added, and the temperature was raised to 120 ° C. Warm
225 parts of 92% paraformaldehyde was successively added over 90 minutes under reflux conditions and reacted. At the end of the reaction, the water content in the reaction system was about 15%. Then, atmospheric distillation was performed and the temperature was raised to 120 ° C. to make the water content about 5%. 1
92% paraformaldehyde 5 under atmospheric distillation at 20 ° C
The reaction was carried out while adding 2 parts over 60 minutes. After completion of the reaction, a reflux reaction was carried out for 30 minutes. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, 50% sodium hydroxide aqueous solution 8
0 part was added slowly. Then, perform atmospheric distillation 1
The temperature was raised to 50 ° C., vacuum distillation was performed at a reduced pressure of 5000 Pa, and the temperature was raised to 150 ° C. to obtain 1125 parts of novolac type phenol resin E.

Example 6 1000 parts of phenol and 2-phosphonobutane-1,2,4 were placed in a 3 L three-necked flask.
-Tricarboxylic acid 50% aqueous solution (PBTC, Johoku Chemical
(Manufactured by Co., Ltd.) was added and the temperature was raised to 120 ° C.
225 parts of paraformaldehyde was successively added over 90 minutes under reflux conditions and reacted. At the end of the reaction, the water content in the reaction system was about 15%. Then, atmospheric distillation is performed, and
The temperature was raised to 0 ° C. to make the water content about 3%. 92% paraformaldehyde 52 parts 60 under atmospheric pressure distillation reaction at 140 ° C 60
The reaction was carried out while gradually adding over. 30 after completion of the reaction
A minute reflux reaction was performed. The reaction composition was sampled and the amount of unreacted phenol was measured using gas chromatography. Then, 71 parts of 50% sodium hydroxide aqueous solution was slowly added. Then, atmospheric distillation is performed, the temperature is raised to 150 ° C., and vacuum distillation is performed at a reduced pressure of 5000 Pa to obtain 1
Raise the temperature to 50 ° C and add 1 to the novolac type phenol resin F.
I got 121 copies.

Comparative Example 1 1000 parts of phenol and 10 parts of oxalic acid were added to a 3 L three-necked flask, and the mixture was heated to 100 ° C.
The temperature is raised to 6% with 707 parts of 37% aqueous formaldehyde solution.
Sequentially added under reflux conditions for 0 minutes, and reacted at 100 ° C. under reflux for 1 hour. At the end of the reaction, the water content in the reaction system was 35%. After completion of the reaction, the reaction composition was sampled and the amount of unreacted phenol was measured by gas chromatography. After that, atmospheric distillation is performed at 130 ° C.
The temperature was raised to 250 ° C. by performing vacuum distillation under reduced pressure of 5000 Pa to obtain 995 parts of novolac type phenol resin E.

The characteristics of the novolac type phenolic resins obtained in Examples 1 to 6 and Comparative Example 1 are shown in Table 1.

[Table 1]

<< Measurement method >> 1. Number average molecular weight and weight average molecular weight: measured by liquid chromatography-liquid chromatography: Tosoh GPC column (G
1000HXL: 1, G2000HXL: 2, G3
000HXL: 1 bottle), the flow rate is 1.0 ml / min, the elution solvent is tetrahydrofuran, and the column temperature is 40 ° C. The GPC measurement is performed using a differential refractometer as a detector under the analysis conditions, and the molecular weight is converted to standard polystyrene. 2. Unreacted phenol amount: measured by gas chromatography. Gas chromatography: Measured by an internal standard method using 2,5-xylenol as an internal standard according to JIS K0114. 3. Softening point: Measured according to JIS K2531. Kinematic viscosity of 4.50% ethanol solution: An ethanol solution of 50% by weight was measured at 25 ° C. using Canon Fenceke. 5. The pH of the resin after the addition of the alkaline substance: 50 g of the resin was sampled, diluted with 50 g of methanol, and 100 g of pure water was added to uniformly disperse the sample to obtain a sample, which was measured using a pH meter. It was

From the results of Table 1, in Examples 1 to 3, the phenols of the present invention were reacted with the aldehydes using an organic phosphonic acid, and a novolac type phenol resin was prepared by adding an alkaline compound after the reaction. Since the method is used and the reaction conditions are within the scope of the claims,
At the end of the reaction, the amount of unreacted phenol was small, and a resin having a high reaction rate with the raw material resin was obtained. The same applies to Example 4, but the amount of water in the reaction system was more than 20% by weight, so that the amount of unreacted phenol at the end of the reaction was large. Further, in Examples 5 and 6, an organic phosphonic acid of a type different from those in Examples 1 to 4 was used, but as in Examples 1 to 3, a resin having a high reaction rate with the resin as the raw material was obtained. On the other hand, the comparative example is based on a conventional method that does not use an organic phosphonic acid as a catalyst, and the amount of unreacted phenol after the reaction is considerably large, and distillation at high temperature is performed to reduce the final amount of unreacted phenol. Operation was required.

[0036]

As described above, the present invention is a method for obtaining a novolak type phenol resin by reacting phenols and aldehydes with an organic phosphonic acid,
A method for producing a novolak type phenolic resin, characterized by adding an alkaline compound after the reaction of phenols and aldehydes, by reducing or eliminating the step of removing unreacted phenols by increasing the reaction rate to the resin. Thus, it is possible to efficiently obtain a novolac-type phenol resin containing a small amount of unreacted phenols in a high yield.

Claims (5)

[Claims] 1. A method for producing a novolak type phenol resin by reacting a phenol and an aldehyde with an organic phosphonic acid, which comprises adding an alkaline substance after the reaction of the phenol and the aldehyde. A method for producing a novolac type phenolic resin, which is characterized. 2. The method for producing a novolac type phenolic resin according to claim 1, wherein the pH of the novolac type phenolic resin becomes 4 to 10 by adding the alkaline substance. 3. The reaction molar ratio (F / P) of the aldehydes (F) to the phenols (P) is 0.5 to 0.9.
5. Organic phosphonic acid was added in an amount of 0.
The method for producing a novolac type phenolic resin according to claim 1 or 2, wherein the amount is 001 to 0.1 mol. 4. The amount of water in the reaction system when reacting phenols and aldehydes with an organic phosphonic acid as a catalyst is 20% by weight or less, and the reaction temperature is 100 to 200 ° C. The method for producing the novolac type phenolic resin according to 1. 5. The method for producing a novolac type phenolic resin according to claim 1, wherein the organic phosphonic acid is represented by the general formula (I). R-PO (OH) ₂ (I) (R contains a carbon atom, and-COOH and / or-
It is a group containing PO (OH) ₂ )