JP2004256786A - Method for producing resol type phenol resin emulsion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a resol type phenol resin emulsion containing few quantity of unreacted phenols and aldehydes. <P>SOLUTION: The method for producing a resol type phenol resin emulsion comprises a process (a) to synthesize a novolac type phenol resin by a reaction of phenols and aldehydes, a process (b) to synthesize a resol type phenol resin whose unreacted monomer content is not more than 1 wt% by a reaction of the above mentioned novolac type phenol resin and aldehydes in the presence of an alkaline catalyst and a process (c) to emulsify the above mentioned resol type phenol resin by addition of a water soluble polymer compound in the course of the synthesis or after the synthesis of the above mentioned resol type phenol resin. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for producing a resol-type phenol resin emulsion.

  Conventionally, as the product form of the resol type phenol resin, an aqueous solution of the resol type phenol resin having a low degree of condensation, an organic solvent solution of the resol type phenol resin having a medium to high degree of condensation, and a resol type phenol resin containing a high concentration of caustic are used. Examples include aqueous solutions, powdery resole phenolic resins, and aqueous emulsions of resole phenolic resins. Some of these forms of resol-type phenolic resins have some problems in terms of generation of harmful substances, flammability, processability, price, storage stability, and the like.

  For example, an aqueous solution of a resol type phenol resin having a low degree of condensation has high reactivity and low storage stability. In addition, since the content of unreacted phenols and aldehydes is large, they are easily released into the air during processing into products, and there is a problem of polluting the working environment and the air. And even after this is processed into a final product, the above-mentioned unreacted components are released from the product, and there is a concern that the living environment will be polluted.

  In addition, an organic solvent solution of a resol type phenol resin having a medium or high degree of condensation has to be removed by evaporating the organic solvent during processing, but it not only generates harmful substances but also has a risk of ignition. I have. Further, the organic solvent is necessary only for maintaining the form as an intermediate product, and is not necessary for the finally processed product, and the raw material cost for the organic solvent is an extra cost.

  On the other hand, a resol-type phenol resin aqueous solution containing a high concentration of caustic tends to damage the adherend or the filler, and as a result, the original performance of the final product may be impaired. May be severely colored.

  In addition, powdery resol-type phenol resin requires a process of solidifying the resol-type phenol resin and pulverizing it, which not only inevitably increases the production cost but also contaminates the working environment due to dusting. In many cases, the workability of handling powder products is not good.

  On the other hand, in the case of an aqueous emulsion of a resol-type phenolic resin, it is desired to develop an aqueous emulsion in which the above-mentioned drawbacks and problems are not included during production and use. As such a technique, for example, a method of adding and dissolving partially saponified PVA after the reaction between phenol and formaldehyde almost reaches an equilibrium state is disclosed (for example, see Patent Document 1). In the case of this method, the amount of unreacted phenol or formaldehyde is said to be reduced in order to shift to the condensation reaction after the polymethylolphenols including trimethylolphenol are sufficiently generated. More than 1% by weight remains in the obtained phenol resin. Furthermore, when an emulsion of a resol-type phenolic resin is generally produced by suspension polymerization or emulsion polymerization, phenol or formaldehyde elutes in equilibrium with the aqueous phase at the beginning of the reaction, and this remains as it remains. Therefore, it is necessary to install relatively expensive equipment such as activated sludge in order to prevent phenol or formaldehyde having high toxicity from leaking into the environment.

  In order to solve the above problem, it is only necessary to synthesize a resol type phenol resin having a very low content of unreacted phenols and aldehydes, and then to emulsify this. However, in general, the resol type phenol resin is prepared such that the molar ratio of the phenols is 1 to 3 moles per mole of the phenols, and the catalyst is sodium hydroxide, aqueous ammonia, a tertiary amine, an oxide of an alkaline earth metal or Hydroxide, obtained by reacting with an alkaline catalyst such as sodium carbonate, when reacted with these catalysts, usually, a large amount of unreacted phenols and aldehydes remain in the phenol resin . Therefore, it has been difficult to solve the above-mentioned problem in an emulsion of a resol-type phenol resin synthesized by an ordinary method.

  As a method for reducing the amount of unreacted phenols and aldehydes, for example, after reacting the aldehydes at a low molar ratio of 1.3 mol or less to 1 mol of the phenols, the unreacted phenols are removed. There is a method in which an aldehyde is reacted at a high molar ratio of 1.7 mol or more with respect to 1 mol of a phenol, and then the unreacted aldehyde is removed.

  As a method for removing unreacted phenols, a steam distillation method is generally known. However, there is a disadvantage that the removal by the steam distillation method has a small effect unless it is carried out for a long time, so that the removal step becomes long.

  In addition, unreacted aldehydes can be removed by adding a catch agent for aldehydes such as urea. May worsen. Further, when the phenol resin is cured at a high temperature, the catch agent and the aldehyde are dissociated, and the aldehyde is generated as a gas, which may cause a problem of air pollution. Further, coloring of the cured product also easily occurs.

  In addition to this, for example, after adding water so that the resin concentration becomes about 5 to 45% by weight, this is preliminarily heated to about 100 to 130 ° C. and the pipe length (L) and the pipe inner diameter (D) Into a tube having a ratio (L / D) of at least 1000 to the tube under reduced pressure, and a large amount of water vapor generated at that time continuously suppresses excessive production and adhesion of condensation polymerization products on the inner surface of the tube wall. There is a method of performing a dehydration treatment (for example, see Patent Document 2). By such an operation, unreacted phenols and aldehydes can be distilled off together with the dehydrating solution. However, these methods have a problem that the steps are extremely complicated and a special apparatus for the washing step is required.

As described above, it is difficult to easily produce a resol type phenol resin having a low content of unreacted phenols and aldehydes, and therefore, a resol type phenol having a low content of unreacted phenols and aldehydes is preferred. It was also difficult to produce an emulsion of the resin.
JP-B-53-32389 JP-B-58-17211

  The present invention provides a method for producing an emulsion of a resol-type phenol resin having a low content of unreacted phenols and aldehydes.

Such an object is achieved by the following present inventions (1) to (7).
(1) In a method for producing a resol-type phenol resin emulsion,
(A) reacting a phenol with an aldehyde under an acidic catalyst to synthesize a novolak-type phenol resin;
(B) reacting the novolak-type phenolic resin with an aldehyde under an alkaline catalyst to synthesize a resol-type phenolic resin having an unreacted monomer content of 1% by weight or less; and
(C) a step of adding a water-soluble polymer compound during or after the synthesis of the resol-type phenolic resin to make the resole-type phenolic resin an emulsion,
A method for producing a resol-type phenolic resin emulsion, comprising:
(2) The method for producing a resol-type phenol resin emulsion according to (1), wherein the novolak-type phenol resin has an unreacted monomer content of 5% by weight or less.
(3) The method for producing a resol-type phenol resin emulsion according to (1) or (2), wherein the acidic catalyst is an organic phosphonic acid.
(4) The method for producing a resol-type phenol resin emulsion according to any one of the above (1) to (3), wherein the organic phosphonic acid is represented by the following general formula (I).

R-PO (OH) ₂ (I)
(R is a group containing a carbon atom and containing -COOH and / or -PO (OH) _2. )
(5) The method for producing a resol-type phenol resin emulsion according to the above (1) or (2), wherein the acidic catalyst is a phosphoric acid aqueous solution.
(6) The method for producing a resol-type phenol resin emulsion according to (5), wherein the aqueous phosphoric acid solution contains 0.2 mol or more of phosphoric acids per 1 mol of the phenols.
(7) The method for producing a resol-type phenol resin emulsion according to (5) or (6), wherein the phosphoric acid is phosphoric acid.

The present invention
(A) reacting a phenol with an aldehyde under an acidic catalyst to synthesize a novolak-type phenol resin;
(B) reacting the novolak-type phenolic resin with an aldehyde under an alkaline catalyst to synthesize a resol-type phenolic resin having an unreacted monomer content of 1% by weight or less; and
(C) a step of adding a water-soluble polymer compound during or after the synthesis of the resol-type phenolic resin to make the resole-type phenolic resin an emulsion,
This is a method for producing a resol-type phenolic resin emulsion, characterized by having the following formula: wherein a resol-type phenolic resin emulsion having a low content of unreacted monomers can be obtained.

  Hereinafter, a method for producing the resol-type phenol resin emulsion of the present invention (hereinafter, may be simply referred to as “production method”) will be described.

The production method of the present invention is a method for producing a resol type phenol resin emulsion,
(A) reacting a phenol with an aldehyde under an acidic catalyst to synthesize a novolak-type phenol resin;
(B) reacting the novolak-type phenolic resin with an aldehyde under an alkaline catalyst to synthesize a resol-type phenolic resin having an unreacted monomer content of 1% by weight or less; and
(C) a step of adding a water-soluble polymer compound during or after the synthesis of the resol-type phenolic resin to make the resole-type phenolic resin an emulsion,
It is characterized by having.

In the production method of the present invention, first,
(A) A phenol and a aldehyde are reacted under an acidic catalyst to synthesize a novolak-type phenol resin.

  In the production method of the present invention, the phenols used in the above-mentioned step (a) are not particularly limited. , Bisphenol A, bisphenol F, resorcin and the like. One or more selected from these phenols can be used, but usually, phenol and cresol are often used.

  In the production method of the present invention, the aldehyde used in the step (a) is not particularly limited, but includes, for example, formaldehyde, acetaldehyde, butyraldehyde, acrolein, a mixture thereof, a substance that is a source of these aldehydes, Alternatively, a solution of these aldehydes may be used. One or more selected from these aldehydes can be used, but usually formaldehyde is often used.

  In the production method of the present invention, the acidic catalyst used in the above step (a) is not particularly limited, but includes an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid, and phosphorous acid, oxalic acid, p-toluenesulfonic acid, and organic phosphonic acid. And other organic acids.

  Among these, it is preferable to use an organic phosphonic acid as the acidic catalyst. This makes it possible to efficiently obtain a novolak-type phenol resin having a small content of unreacted monomers.

  In the production method of the present invention, the "unreacted monomer" refers to both "unreacted phenols" and "unreacted aldehydes", and the "content of unreacted monomers" It refers to both the "content of unreacted phenols" and the "content of unreacted aldehydes".

The organic phosphonic acid is an organic compound containing a phosphonic acid group -PO (OH) ₂ , and any compound can be used. However, the organic phosphonic acid represented by the following general formula (I) may It is preferable for producing a novolak type phenol resin having a small content.

R-PO (OH) ₂ (I)
(R is a group containing a carbon atom and containing -COOH and / or -PO (OH) _2. )
Examples of the organic phosphonic acid represented by the general formula (I) include aminopolyphosphonic acids such as ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, and β-aminoethylphosphonic acid N, N-diacid. Acetic acid, aminomethylphosphonic acid N, N-diacetic acid, 1-hydroxyethylidene-1,1′-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid and the like. Of these, aminotrismethylene phosphonic acid, 1-hydroxyethylidene-1,1′-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid, which are industrially mass-produced and inexpensive, are preferred.

  The amount of the organic phosphonic acid to be added is not particularly limited, but is 0.001 to 3.0 mol, preferably 0.01 to 2.0 mol, per 1 mol of the phenol. Even if the amount exceeds the upper limit, the effect of reducing the content of the unreacted monomer remains unchanged. Below the lower limit, the effect of using the organic phosphonic acid is small.

The reaction conditions when the above-mentioned organic phosphonic acid is used are not particularly limited, but are usually 40 to 240 ° C, preferably 80 to 140 ° C. When the reaction temperature is lower than 40 ° C., the progress of the reaction is slow, and it takes time to sufficiently reduce the content of the unreacted monomer. At a temperature higher than 240 ° C., the organic phosphonic acid is hydrolyzed.
The reaction time is not particularly limited and may be appropriately determined depending on the type of starting materials, the molar ratio of the starting materials, the amount of the catalyst used, and the reaction conditions.

  Further, it is preferable to use a phosphoric acid aqueous solution as the acidic catalyst. Thereby, the same effect as in the case of using the organic phosphonic acid can be obtained.

  Here, as the phosphoric acid, a phosphoric acid compound which can be dissolved in water to form a phosphoric acid aqueous solution can be used, and is not particularly limited. For example, phosphoric acid (orthophosphoric acid), diphosphoric acid, triphosphoric acid and the like can be used. In addition to linear polyphosphoric acid, cyclic polyphosphoric acid, diphosphorus pentoxide, phosphorous acid, hypophosphorous acid, and the like, various phosphate ester compounds can be mentioned. These can be used alone or in combination of two or more.

  Of these phosphoric acids, phosphoric acid is preferred. Phosphoric acid can be easily adjusted in concentration and can be obtained at low cost.

  The concentration of the phosphoric acid in the aqueous phosphoric acid solution is not particularly limited, but is preferably from 20 to 99% by weight, and more preferably from 40 to 99% by weight. By setting the concentration of the phosphoric acid in the aqueous phosphoric acid solution to be equal to or higher than the lower limit, the reaction between the phenol and the aldehyde can efficiently proceed.

  The amount of the phosphoric acid used here is not particularly limited, but is preferably 0.2 mol or more based on 1 mol of the phenol. Thereby, in a system in which a phenol and an aldehyde are reacted using an aqueous solution of phosphoric acid, the distribution of an organic phase containing phenol as a main component and an aqueous phase composed of an aqueous solution of phosphoric acid can be stabilized.

  The amount of the phosphoric acid is more preferably from 0.3 to 1.0 mol, and particularly preferably from 0.4 to 0.9 mol, per 1 mol of the phenol. Thereby, a novolak-type phenol resin having a low content of unreacted phenols can be efficiently obtained.

  When the amount of the phosphoric acids is increased, the effect of obtaining a novolak-type phenol resin having a low content of unreacted phenols in a high yield tends to be large. If the amount exceeds the above, the effect may not be substantially changed and may not be economical. If the amount is less than 0.2 mol, the concentration of the phosphoric acid in the aqueous phase becomes too low to stably partition the organic phase and the aqueous phase, so that the reaction rate is reduced.

  The reaction conditions when the above-mentioned phosphoric acid aqueous solution is used as the acidic catalyst are not particularly limited, but the reaction temperature is preferably 40 to 150 ° C. More preferably, it is 90 to 140 ° C. When the reaction temperature is equal to or higher than the lower limit, the reaction between phenols and aldehydes can be promoted, and the content of unreacted phenols can be reduced. Further, the phosphoric acid aqueous solution can be made to have a preferable viscosity, and the catalytic action can be prevented from being lowered. On the other hand, when the content is not more than the upper limit, the decomposition of the novolak-type phenol resin can be suppressed.

  The water content of the reaction system during the reaction is preferably in the range of 1 to 40% by weight or less. As a reaction mode, an atmospheric pressure reaction is a preferable condition in terms of controlling temperature and moisture. Other possible reaction conditions include a solvent reflux dehydration reaction using a non-aqueous solvent such as butanol and propanol, and a high-pressure reaction. Further, the stirring speed during the reaction is preferably high.

  When the organic phosphonic acid or the aqueous solution of phosphoric acid is used as a catalyst in the step (a), in addition to these catalysts, oxalic acid, sulfuric acid, hydrochloric acid, p-toluenesulfonic acid and the like, usually a novolak type It is also possible to use an acid used in the production of a phenol resin. The combined use of these acids is effective for accelerating the reaction particularly when a polymer region having four or more nuclei is required, and is an effective means for controlling the molecular weight distribution.

In the production method of the present invention, the reaction molar ratio of the phenol and the aldehyde used in the step (a) is not particularly limited. However, when an organic phosphonic acid is used as the acidic catalyst, the aldehyde (P) is reacted with the aldehyde (P). F ₁₎ the molar ratio of _(F 1 / P) is preferably from 0.1 to 0.85, more preferably from 0.3 to 0.8.

  Moreover, when using the said phosphoric acid aqueous solution as an acidic catalyst, it is 0.1-1.0 normally, Preferably it is 0.5-0.95, More preferably, it is 0.6-0.9. .

  This makes it possible to efficiently obtain a novolak-type phenol resin having a small content of unreacted monomers. When the molar ratio is smaller than the lower limit, the content of unreacted phenols tends to increase, and it is difficult to obtain a low content of unreacted phenols even when this is converted into a resole resin. is there. On the other hand, when the molar ratio exceeds the above upper limit, in the step of converting the novolak type phenol resin into a resol resin, the viscosity may be increased or gelled depending on reaction conditions.

Further, the organic phosphonic acid as an acidic catalyst or, in the case of using something other than the phosphoric acids aqueous solution, it is preferable to molar ratio (F 1 _{/ P)} and from 0.05 to 0.8, more preferably 0 .1 to 0.7.

  When the phosphoric acid aqueous solution is used as the acidic catalyst, the reaction molar ratio (F / P) between the phenol (P) and the aldehyde (F) is set to 0.8 to 0.95, and the reaction temperature is set to 0.8 to 0.95. By effecting the reaction at 80 to 150 ° C., an effect of reducing the content of the binuclear component can be provided.

  The method of reacting the phenols and aldehydes is not particularly limited, but at the beginning of the reaction, the phenols and aldehydes may be charged in a lump and the catalyst may be reacted. In order to suppress this, phenols and a catalyst may be mixed, and then aldehydes may be sequentially added and reacted.

  In the step (a), as described above, it is preferable that the phenols and the aldehydes are obtained by reacting with the organic phosphonic acid or the phosphoric acid aqueous solution as a catalyst. However, besides this, the reaction can also be carried out using a known acidic catalyst.

  At this time, the addition amount of the acidic catalyst is not particularly limited, but is preferably 0.001 to 0.1 mol, more preferably 0.005 to 0.05 mol, per 1 mol of the phenol. . In addition, the reaction can be carried out under reflux conditions where temperature control is easy.

  In this case, the amount of unreacted phenols or binuclear components contained in the obtained resin may increase, so that atmospheric distillation, vacuum distillation, steam distillation, recrystallization, solvent extraction, and water washing are performed. This can be removed by any of the methods described above.

  As an example, unreacted phenols can be removed under a reduced pressure condition of 170 ° C. and 500 Pa, and a binuclear component can be removed under a reduced pressure condition of 250 ° C. and 100 Pa.

  Although not particularly limited in the production method of the present invention, the content of the unreacted monomer contained in the novolak-type phenol resin synthesized in the above step (a) is preferably 5% by weight or less. More preferably, it is at most 3% by weight. This makes it possible to efficiently obtain a resol-type phenol resin having a small content of unreacted monomers, and to produce a resol-type phenol resin emulsion having a small burden on the environment.

  In the production method of the present invention, the method for controlling the content of the unreacted monomer contained in the novolak-type phenol resin synthesized in the step (a) to not more than the upper limit value is not particularly limited. When an organic phosphonic acid or the above-mentioned aqueous solution of phosphoric acid is used, it can be generally adjusted to the upper limit or less by the reaction. Further, if necessary, unreacted monomers may be removed by a combination of atmospheric distillation, vacuum distillation and the like.

  When other than these are used as the acidic catalyst, unreacted monomers may be removed by normal pressure distillation, reduced pressure distillation or the like after synthesizing the novolak type phenol resin.

  After synthesizing the novolak type phenol resin, water and a solvent may be added for the purpose of adjusting the viscosity in some cases.

  In the step (a), when the organic phosphonic acid or the phosphoric acid aqueous solution is used as the acidic catalyst, the organic phosphonic acid or the phosphoric acid can be removed or recovered by washing with water after the completion of the reaction. However, there is no particular limitation on the removal or recovery method and the washing method. The organic phosphonic acid or phosphoric acid recovered by washing with water can be used again as a catalyst.

  Further, neutralization may be carried out with an alkaline substance, and furthermore, an alkaline substance may be excessively added and resolving may be performed as it is.

Next, in the production method of the present invention,
(B) The novolak type phenol resin is reacted with an aldehyde under an alkaline catalyst to synthesize a resol type phenol resin having an unreacted monomer content of 1% by weight or less.

  In the production method of the present invention, the aldehyde used in the above-mentioned step (b) is not particularly limited. For example, formaldehyde, acetaldehyde, butyraldehyde, acrolein, a mixture thereof, a substance which is a source of these aldehydes, Alternatively, a solution of these aldehydes may be used. One or more selected from these aldehydes can be used, but usually formaldehyde is often used.

In the production method of the present invention, the amount of the aldehyde used in the step (b) is not particularly limited, but the unreacted phenol remaining in the phenol resin may be removed in the step (a). In view of the above, the phenol (P) used in the step (a) and the aldehydes (F ₁ ) used in the step (a) and the phenol (F ₁ ) used in the step (b) are used in the step (b). the sum of the aldehyde _{(F 2),} it is preferable that the molar ratio _{[(F 1 + F 2)} / P] in 0.7 to 3.0, more preferably from 0.8 to 2.5. If the molar ratio is smaller than the above lower limit, resolification in the step (b) may be insufficient, and if the molar ratio exceeds the upper limit, a large amount of unreacted aldehydes will remain.

  In the production method of the present invention, the alkaline catalyst used in the above-mentioned step (b) is not particularly limited, and examples thereof include hydroxides of alkali metals such as sodium, lithium and potassium, and alkaline earth metals such as calcium, magnesium and barium. Oxides and hydroxides, aqueous ammonia, tertiary amines such as triethylamine, and alkaline substances such as sodium carbonate and hexamethylenetetramine.

  The amount of the alkaline catalyst to be added is not particularly limited, but is usually in the range of 0.01 to 0.5 mol, preferably 0.05 to 0.3 mol, per 1 mol of the phenol used in the step (a). Is a mole. If the amount of the alkaline catalyst is less than the above lower limit, the action as a catalyst may not be sufficient, while if it is more than the above upper limit, the curability may be affected.

The alkaline catalyst used in the step (b) may be removed by washing with water after the reaction, or may be neutralized by adding an acidic substance. Thereby, the influence of the remaining alkaline catalyst can be reduced.
In the production method of the present invention, the content of the unreacted monomer in the resol-type phenol resin obtained in the step (b) is 1% by weight or less.

  The method for reducing the content of the unreacted monomer in the resole type phenol resin to 1% by weight or less is not particularly limited. In the step (a), a novolak type phenol resin having a small content of the unreacted monomer is synthesized. It is preferable to synthesize a resol type phenol resin based on this. As a result, a resol-type phenol resin having an unreacted monomer content of 1% by weight or less can be obtained without causing problems such as an increase in the molecular weight of the resin and gelation.

  In addition, if necessary, a conventionally known process or method for removing unreacted monomers can be used in combination.

  In the production method of the present invention, in the step (a), a novolak-type phenol resin is synthesized from a phenol and an aldehyde using the organic phosphonic acid or the phosphoric acid aqueous solution as a catalyst. The reason why a resol-type phenolic resin having a reduced content of unreacted monomers can be obtained by synthesizing a resol-type phenolic resin from the above is considered as follows.

  Organic phosphonic acids and phosphoric acids are very water-soluble. Phenols and aldehydes have relatively low solubility in water, and novolak-type phenol resins have a property that the solubility in water is further reduced as the molecular weight increases. Therefore, at the start of the reaction, a phase is separated into an aqueous phase containing a large amount of the organic phosphonic acid or phosphoric acid as a catalyst and an organic phase composed of phenols having almost no catalyst. Then, the reaction between the phenol and the aldehyde eluted in the aqueous phase proceeds preferentially, and as a result, the content of the unreacted phenol decreases. Further, since the reaction product having two or more nuclei is less likely to react to polymerization due to the above-mentioned catalytic properties, the novolak type having a low content of unreacted phenols and a high content of the two nucleus components is preferable. A phenolic resin is obtained. Next, by using the obtained novolak-type phenol resin as a raw material, resolving by adding a necessary amount of aldehydes, the content of unreacted monomer is small, and a resol-type phenol resin having a desired molecular weight is produced. It becomes possible.

  Next, in the production method of the present invention, (c) a water-soluble polymer is added during or after the synthesis of the resole-type phenol resin, and the resole-type phenol resin is emulsified.

In the production method of the present invention, as a method of adding a water-soluble polymer to the resole-type phenol resin synthesized in the above step (b) to form an emulsion, for example, the following method is available.
(I) A novolak-type phenol resin and an aldehyde are allowed to react halfway in the presence of an alkaline catalyst, a water-soluble polymer compound is added, and the reaction is further continued. An emulsion of the resin is obtained.
(II) The novolak-type phenolic resin is reacted with an aldehyde in the presence of an alkaline catalyst. After the reaction is completed, a water-soluble polymer compound is added, and the mixture is uniformly mixed. obtain.

  In the production method of the present invention, the water-soluble polymer compound used in the step (c) is not particularly limited, but those generally called protective colloids are preferable. For example, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, carboxylic acid Examples include ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, polyacrylamides, starch, gelatin, casein, gum arabic, polyethylene oxide and the like.

  Polyacrylamides are not particularly limited, for example, polyacrylamide, polymethacrylamide, polyacrylamide and partially hydrolyzed polymethacrylamide, copolymer of acrylic acid and acrylic acid or methacrylic acid, vinyl -Based polyvinyl amide copolymer, cationized polyacryl amide, amphoteric polyacryl amide, sulfomethylene polyacryl amide, urethanized polyvinyl alcohol, etc. containing an acid amide group in the molecule, or methylolated Methylol compounds of the above acid amides such as polyacrylamide and the like.

  The form in which these water-soluble polymers are used is not particularly limited. For example, a water-soluble polymer prepared as an aqueous solution may be added, or these water-soluble polymers are dissolved in the reaction system. If time can be secured, it can be added in the form of a powder.

  In the production method of the present invention, the addition amount of the water-soluble polymer compound used in the step (c) is not particularly limited, but usually, the total amount of the components excluding water in the final resol-type phenol resin emulsion is excluded. Is used in an amount of 0.1 to 60% by weight. More preferably, it is 0.5 to 15% by weight.

  The amount of the water-soluble polymer can be set as appropriate according to the type of the water-soluble polymer to be added and the use of the resol-type phenol resin emulsion.

  When obtaining a resol-type phenol resin emulsion, a dispersing aid can be used in combination with the above water-soluble polymer compound, if necessary.

  Here, the dispersing aid is not particularly limited, but surfactants, chelating agents, and those commonly referred to as protective colloids can be used. For example, anionic, cationic, nonionic, and zwitterionic surfactants can be used. Agents, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, sodium alginate, polyvinyl alcohol, polyvinyl acetate partial hydrolyzate, starches, tragacanth gum, casein, gelatin, gluten, polyvinyl methyl ether, polyvinylpyrrolidone, styrene maleic anhydride copolymer, Protective colloid materials such as polyacrylic acid and polyethylene glycol are exemplified. These dispersing aids can be selected depending on the type of the alkaline catalyst, the use of the resole type phenol resin emulsion, and the like, but when used, a small amount of addition is sufficient. The timing of addition may be before or after the addition of the water-soluble polymer, or may be simultaneous.

  In the method for producing a resol-type phenol resin emulsion of the present invention, the reaction apparatus used in the above steps (a) to (c) is not particularly limited, but the reaction can be performed using a normal reaction vessel. In particular, also in the step (c), forced stirring by a so-called emulsifying apparatus such as a homodisper, a homomixer, a homogenizer, and a wet mill is not required. However, if necessary, the above-described emulsifying apparatus may be used in combination.

As described above, in the method for producing a resol-type phenol resin emulsion of the present invention,
(A) reacting a phenol with an aldehyde under an acidic catalyst to synthesize a novolak-type phenol resin;
(B) reacting the novolak-type phenolic resin with an aldehyde under an alkaline catalyst to synthesize a resol-type phenolic resin having an unreacted monomer content of 1% by weight or less; and
(C) during or after the synthesis of the resol-type phenol resin, a step of adding a water-soluble polymer compound to make the resol-type phenol resin an emulsion;
It is characterized by having.

  In the step (b), the novolak-type phenol resin synthesized in the step (a) preferably has a low content of the unreacted monomer, so that no complicated operation is required in the step (b). A resol-type phenol resin having a content of 1% by weight or less can be obtained.

  In particular, in the step (a), by using the organic phosphonic acid or the phosphoric acid aqueous solution as the acidic catalyst, the novolak-type phenol resin and the resol-type phenol resin having a small content of the unreacted monomer can be efficiently converted. Obtainable.

  Then, by emulsifying the resol-type phenol resin in the step (c), an emulsion of the resol-type phenol resin having a low content of unreacted monomer can be produced.

  The resol-type phenol resin emulsion thus obtained is in a form not using an organic solvent, and has a small content of unreacted monomer contained therein, so that it is only excellent in workability, safety and health. In addition, since the amount of unreacted monomer in the waste liquid discharged at the time of use can be suppressed to a small amount, the burden on the environment can be reduced. Furthermore, when treating such a waste liquid, there is an advantage that expensive treatment equipment for activated sludge or the like is not required.

Hereinafter, the present invention will be described in detail with reference to examples. “Parts” and “%” described herein all indicate “parts by weight” and “% by weight”.
(Example 1)
In a three-necked flask equipped with a stirrer and a thermometer, 1000 parts of a 60% aqueous solution of 1-hydroxyethylidene-1,1′-diphosphonic acid (manufactured by Lion Corporation, “Feriox 115”) is charged, and the temperature is raised to 120 ° C. to obtain a concentration. It concentrated under normal pressure until it became 85%. Thereafter, 1000 parts of phenol was charged and the temperature was raised to 100 ° C., and then 650 parts of 37% formaldehyde (molar ratio F ₁ /P=0.75) were successively added over 2 hours. Then, after adding and mixing 500 parts of pure water, the temperature was lowered to 60 ° C. to remove the catalyst. In order to remove the residual catalyst, water washing was performed twice by adding, mixing and removing 1000 parts of pure water. The content of unreacted phenol in the obtained novolak-type phenol resin was 0.8%, and the content of unreacted aldehyde was 0.0%.

Next, 30 parts of calcium hydroxide and 475 parts of 37% formaldehyde (molar ratio to charged phenol F ₂ /P=0.55) were added, and the mixture was heated to 80 ° C. and refluxed for 2 hours. After the reaction, vacuum distillation was performed at 15000 Pa, and the amount of water in the flask was adjusted to 25% by weight with respect to the total amount of the reaction product and the amount of water. Thereafter, 670 parts of polyacrylamide ("Polystron 117" manufactured by Arakawa Chemical Industry Co., Ltd., 15% aqueous solution) was added, 990 parts of water was added, and the mixture was stirred for 1 hour, and 3250 parts of an emulsion A of resol-type phenol resin was added. Got. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Further, the supernatant was separated by centrifugation (10000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.
(Example 2)
In the same manner as in Example 1, 1000 parts of phenol and 10 parts of oxalic acid were charged in a three-necked flask, and the temperature was raised to 100 ° C., and 430 parts of 37% formaldehyde (molar ratio F ₁ /P=0.5) was added over 2 hours. It was added one by one. Then, after performing a reflux reaction for 2 hours, normal pressure distillation was performed up to 150 ° C., and further vacuum distillation was performed at 250 Pa up to 250 ° C. The content of unreacted phenol in the resulting novolak phenol resin was 0.0%, and the content of unreacted aldehyde was 0.0%.

Next, after cooling to 50 ° C. while adding 80 parts of water, 30 parts of calcium hydroxide and 400 parts of 37% formaldehyde (molar ratio F _{2 /} P to charged phenol = 0.46) were added. C. and the reflux reaction was carried out for 2 hours. After the reaction, 670 parts of polyacrylamide ("Polystron 117", 15% aqueous solution, manufactured by Arakawa Chemical Industries, Ltd.) was added, 600 parts of water was added, and the mixture was stirred for 1 hour. B2450 parts were obtained. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Further, the supernatant was separated by centrifugation (10000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.
(Example 3)
In a three-necked flask, 1000 parts of a 60% aqueous solution of 1-hydroxyethylidene-1,1′-diphosphonic acid (manufactured by Lion Corporation, “Feriox 115”) was charged in the same manner as in Example 1, and the temperature was raised to 120 ° C. to give a concentration of 85. % Under normal pressure. Thereafter, 1000 parts of phenol was charged and the temperature was raised to 100 ° C., and then 650 parts of 37% formaldehyde (molar ratio F ₁ /P=0.75) were successively added over 2 hours. Thereafter, in order to remove the residual catalyst, 500 parts of pure water was added and mixed, and the aqueous phase separated from the resin phase was removed. The content of unreacted phenol in the obtained novolak-type phenol resin was 0.8%, and the content of unreacted aldehyde was 0.0%.

Next, 30 parts of calcium hydroxide, after addition of 260 parts of 37% formaldehyde (molar ratio _F 2 /P=0.3 on the charged phenol) was reacted for 1 hour 30 minutes at 70 ° C.. After the reaction, the mixture was neutralized with a 25% aqueous sulfuric acid solution to adjust the pH to 5.6. Thereafter, 740 parts of polyacrylamide ("Polystron 117" manufactured by Arakawa Chemical Industries, Ltd., 15% aqueous solution) was added, and 560 parts of water were added to obtain 2930 parts of a resol-type phenol resin emulsion C29. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Further, the supernatant was separated by centrifugation (10000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.
(Example 4)
In the same manner as in Example 1, 1000 parts of phenol and 10 parts of oxalic acid were charged in a three-necked flask, and the temperature was raised to 100 ° C., and 430 parts of 37% formaldehyde (molar ratio F ₁ /P=0.5) was added over 2 hours. It was added one by one. Then, after performing a reflux reaction for 2 hours, normal pressure distillation was performed up to 150 ° C., and further vacuum distillation was performed at 250 Pa up to 250 ° C. The content of unreacted phenol in the resulting novolak phenol resin was 0.0%, and the content of unreacted aldehyde was 0.0%.

Next, after cooling to 50 ° C. while adding 80 parts of water, 30 parts of calcium hydroxide and 345 parts of 37% formaldehyde (molar ratio to charged phenol F ₂ /P=0.4) were added, and then The reaction was carried out at a temperature of 1 hour and 30 minutes. After the reaction, the mixture was neutralized with a 25% aqueous sulfuric acid solution to adjust the pH to 5.2. Thereafter, 600 parts of polyacrylamide ("Polystron 117" manufactured by Arakawa Chemical Industries, Ltd., 15% aqueous solution) was added, and 255 parts of water was added to obtain 2260 parts of an emulsion D2 of a resol-type phenol resin. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Furthermore, the supernatant was separated by centrifugation (10,000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.
(Example 5)
In the same manner as in Example 1, 1000 parts of phenol and 1000 parts of an 85% phosphoric acid aqueous solution (corresponding to 0.82 mol with respect to 1 mol of phenols) were added to a three-necked flask, and the temperature was raised to 100 ° C., and 37% formaldehyde was added. 570 parts of an aqueous solution (molar ratio F ₁ /P=0.66) were sequentially added over 2 hours, and the mixture was reacted at 100 ° C. for 1 hour under reflux. Thereafter, in order to remove the residual catalyst, 500 parts of pure water was added and mixed, and the aqueous phase separated from the resin phase was removed. Such a washing step was performed three times. The content of unreacted phenol in the obtained novolak phenol resin was 0.2%, and the content of unreacted aldehyde was 0.0%.

Next, after adding 30 parts of calcium hydroxide and 380 parts of 37% formaldehyde (molar ratio to charged phenol F ₂ /P=0.44), the mixture was reacted at 70 ° C. for 1 hour and 30 minutes. After the reaction, the mixture was neutralized with a 25% aqueous sulfuric acid solution to adjust the pH to 5.3. Thereafter, 740 parts of polyacrylamide ("Polystron 117" manufactured by Arakawa Chemical Industries, Ltd., 15% aqueous solution) was added, and 350 parts of water was added to obtain 2970 parts of an emulsion E of resol type phenol resin. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Further, the supernatant was separated by centrifugation (10000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.
(Comparative example)
In the same flask as in Example 1, 1000 parts of phenol, 1120 parts of 37% formaldehyde (molar ratio F / P = 1.3) and 30 parts of calcium hydroxide as a catalyst were added and reacted at 80 ° C. for 3 hours. . After the reaction, vacuum distillation was performed at 15000 Pa, and the water content in the flask was adjusted to 25% by weight with respect to the total amount of the reaction product and the water content.

  Next, 670 parts of polyacrylamide ("Polystron 117" manufactured by Arakawa Chemical Industry Co., Ltd., 15% aqueous solution) was added, 940 parts of water was added, and the mixture was stirred for 1 hour to prepare an emulsion F3110 of a resol-type phenol resin. Got a part. A part of the sample was sampled, and the content of unreacted phenol and the content of unreacted aldehyde were measured. Further, the supernatant was separated by centrifugation (10000 rotations, 10 minutes), and the content of unreacted phenol and unreacted aldehyde in the supernatant was measured.

  The characteristics of the resol-type phenolic resins obtained in Examples and Comparative Examples were evaluated. Table 1 shows the results.

Evaluation method (1) Solid content concentration: The ratio of the solid content to the amount of the resol-type phenol resin emulsion was calculated in accordance with JIS K 6909. The solid content was calculated from the remaining amount when the resol-type phenol resin emulsion was placed in an aluminum foil container and heated for 1 hour in a dryer heated to 135 ° C.
(2) Gelation time: Measured with a hot plate at 150 ° C. using 2 ml of resole type phenolic resin in accordance with JIS K 6909.
(3) Content of unreacted phenol in novolak-type phenolic resin and resol-type phenolic resin: Measured by an internal standard method using 2,5-xylenol as an internal standard in accordance with JIS K 0114.
(4) Content of unreacted formaldehyde in novolak-type phenol resin and resol-type phenol resin: Measured by the hydroxylamine hydrochloride method.
(5) The content of unreacted phenol and the content of unreacted formaldehyde in the supernatant: a pack test for simplified water quality analysis (manufactured by Kyoritsu RIKEN, for phenol; model WAK-PNL, for formaldehyde; model, WAK- FOR) and by diluting to an arbitrary magnification.

  All the examples are resol type phenolic resin emulsions obtained by the production method of the present invention, and without substantially affecting other properties, the content of unreacted monomer is small. An emulsion could be obtained.

  On the other hand, in the comparative example, a resol-type phenol resin was synthesized by a conventional method, and this was emulsified, but in the emulsion and the supernatant, the content of the unreacted monomer was large. .

  The resol-type phenolic resin emulsion obtained by the production method of the present invention is useful, for example, as an adhesive, a water-based paint, a binder for organic fibers such as inorganic fibers such as rock wool and glass fibers, and pulp, and a latex compounding agent. It is excellent in workability, environmental pollution, price and the like.

Claims (7)

In a method for producing a resol type phenol resin emulsion,
(A) reacting a phenol with an aldehyde under an acidic catalyst to synthesize a novolak-type phenol resin;
(B) reacting the novolak-type phenolic resin with an aldehyde under an alkaline catalyst to synthesize a resol-type phenolic resin having an unreacted monomer content of 1% by weight or less; and
(C) a step of adding a water-soluble polymer compound during or after the synthesis of the resol-type phenol resin to form an emulsion of the resol-type phenol resin;
A method for producing a resol-type phenolic resin emulsion, comprising: The method for producing a resol-type phenol resin emulsion according to claim 1, wherein the novolak-type phenol resin has an unreacted monomer content of 5% by weight or less. The method for producing a resol-type phenol resin emulsion according to claim 1 or 2, wherein the acidic catalyst is an organic phosphonic acid. The method for producing a resol-type phenol resin emulsion according to any one of claims 1 to 3, wherein the organic phosphonic acid is represented by the following general formula (I).
R-PO (OH) ₂ (I)
(R is a group containing a carbon atom and containing -COOH and / or -PO (OH) _2. ) The method for producing a resol-type phenol resin emulsion according to claim 1 or 2, wherein the acidic catalyst is a phosphoric acid aqueous solution. The method for producing a resol-type phenol resin emulsion according to claim 5, wherein the phosphoric acid aqueous solution contains 0.2 mol or more of phosphoric acid per 1 mol of the phenol. The method according to claim 5, wherein the phosphoric acid is phosphoric acid.