JP2004137470A - Method for producing novolac-type phenolic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a novolac-type phenolic resin in which an acidic catalyst, particularly an organic phosphonic acid catalyst and a phosphoric acid-based catalyst, remaining in the novolac-type phenolic resin can be efficiently removed in a short time by washing with water. <P>SOLUTION: The method for producing the novolac-type phenolic resin comprises the steps of (a) reacting phenols and aldehydes in the presence of the acidic catalyst and (b) washing the novolac-type phenolic resin in the reaction product obtained by the step (a) with water using a continuous mixer. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for producing a novolak type phenol resin.

The novolak-type phenol resin is obtained by reacting phenols and aldehydes with an inorganic or organic acid such as hydrochloric acid, sulfuric acid, oxalic acid or p-toluenesulfonic acid as a catalyst.
Here, when oxalic acid, hydrochloric acid, or the like is used as the catalyst, the catalyst is also decomposed by heat and removed to the outside in the dehydration step up to about 180 ° C. in the latter half of the reaction. However, when a catalyst such as sulfuric acid or p-toluenesulfonic acid is used, these acids do not decompose with heat of about 180 ° C., so that it is necessary to perform treatments such as washing with water and neutralization after completion of the reaction. This is because, if the acid component remains in the novolak resin, when the resin is exposed to a high temperature for a long period of time, the molecules are rearranged and gelation easily occurs. Similarly, when an organic phosphonic acid or phosphoric acid aqueous solution is used as a catalyst, treatment such as washing with water or neutralization is required after the completion of the reaction.
When the catalyst in the resin is washed with water, generally, it is necessary to add the same amount of water as the resin, and after stirring and mixing, it is necessary to repeat the process of standing and separating, which requires a large number of steps. (For example, see Non-Patent Documents 1 and 2).

Andre Knop / Louis A. Pilato, "Phenolic Resin", Plastic Age Co., Ltd., June 20, 1980, p. 83-85 Akihiro Matsumoto, "Synthesis, Hardening, Toughening and Application of Phenolic Resin", IPC, January 20, 2000, p. 8-10

The present invention provides a method for producing a novolak-type phenol resin that can efficiently wash and remove acidic catalysts remaining in the novolak-type phenol resin, particularly an organic phosphonic acid catalyst and a phosphoric acid aqueous solution catalyst in a short time. is there.

Such an object is achieved by the following present inventions (1) to (8).
(1) In a method for producing a novolak type phenol resin,
(A) reacting a phenol with an aldehyde under an acidic catalyst;
(B) washing the novolak-type phenol resin in the reaction product obtained in the step (a) with a continuous mixing device,
A method for producing a novolak-type phenol resin, comprising:
(2) The method for producing a novolak-type phenolic resin according to the above (1), wherein the reaction product contains a novolak-type phenolic resin having a softening point of 90 ° C. or higher.
(3) In the step (b), production of the novolak-type phenolic resin according to the above (1) or (2), wherein hot water and steam are simultaneously fed into the continuous mixing device together with the novolak-type phenolic resin. Method.
(4) The method for producing a novolak type phenol resin according to any one of the above (1) to (3), wherein in the step (b), the continuous mixing device is a static mixer.
(5) The method for producing a novolak-type phenol resin according to any one of the above (1) to (4), wherein in the step (a), the acidic catalyst is an organic phosphonic acid.
(6) The method for producing a novolak-type phenol resin according to (5), 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 )
(7) The method according to any one of (1) to (4), wherein in the step (a), the acidic catalyst is a phosphoric acid aqueous solution, and the phosphoric acid is used in an amount of 0.2 mol or more per 1 mol of the phenol. A method for producing the novolak-type phenol resin described in the above.
(8) The method for producing a novolak-type phenol resin according to (7), wherein the phosphoric acid is phosphoric acid.

The present invention relates to a method for producing a novolak-type phenolic resin, comprising: (a) reacting a phenol with an aldehyde under an acidic catalyst; and (b) novolak in the reaction product obtained in the step (a). Washing the phenolic resin with water using a continuous mixing device, and a method for producing a novolak-type phenolic resin, wherein the acidic catalyst remaining in the novolak-type phenolic resin, particularly an organic phosphonic acid catalyst And the phosphoric acid catalyst can be efficiently washed and removed in a short time.

Hereinafter, the method for producing the novolak type phenol resin of the present invention will be described.
The present invention relates to a method for producing a novolak-type phenol resin (hereinafter, sometimes simply referred to as a “production method”).
(A) reacting a phenol with an aldehyde under an acidic catalyst;
(B) washing the novolak-type phenol resin in the reaction product obtained in the step (a) with a continuous mixing device,
It is characterized by having.

First, in the production method of the present invention, the step (a) of reacting a phenol with an aldehyde under an acidic catalyst will be described.
The phenol used in the step (a) is not particularly limited, but is preferably phenol, ortho-cresol, meta-cresol, para-cresol, xylenol, para-tert-butylphenol, para-octyl phenol, para-phenyl phenol, bisphenol At least one phenol selected from A, bisphenol F, resorcin and the like.

The aldehyde used in the step (a) is not particularly limited, but is preferably formaldehyde, acetaldehyde, butyraldehyde, acrolein, or a mixture thereof. It is also possible to use substances or solutions of these aldehydes.

The reaction molar ratio of the phenols to the aldehydes is not particularly limited, but is 0.1 to 3.0 moles, preferably 0.5 to 1.0 moles, with respect to 1.0 moles of the phenols. Although there is no particular limitation on the method of the reaction, for example, at the start of the reaction, all of the phenols and aldehydes may be charged at once, and a catalyst may be added thereto to cause a reaction. In order to suppress the reaction, phenols and a catalyst may be added, and then aldehydes may be sequentially added and reacted.

The acidic catalyst used in the above step (a) is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and phosphorous acid, oxalic acid, diethyl sulfate, paratoluenesulfonic acid, and organic phosphonic acid. Organic acids and metal salts such as zinc acetate are exemplified. These can be used alone or in combination of two or more.
Among them, particularly when an organic phosphonic acid and a predetermined amount of an aqueous solution of phosphoric acid are used, a novolak-type phenol resin having a narrow molecular weight distribution and a low melt viscosity can be obtained. It is particularly suitable for removing catalyst components remaining therein.

First, the case where an organic phosphonic acid is used will be described.
The organic phosphonic acid is an organic compound containing a phosphonic acid group -PO (OH) ₂ , and any compound can be used. However, the phosphonic acid represented by the following general formula (I) has a low level of unreacted phenols. It is preferable for obtaining a novolak-type phenol resin having a narrow molecular weight distribution in a high yield.
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, for example, aminopolyphosphonic acids such as ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, and β-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, are preferred.

When the organic phosphonic acid is used as the acidic catalyst, the amount thereof is not particularly limited, but is 0.001 to 4.0 mol, preferably 0.01 to 0.5 mol, per 1 mol of the phenol. The greater the amount of the organic phosphonic acid added, the less unreacted phenols and the higher the yield of a novolak-type phenolic resin with a narrow molecular weight distribution, but the greater the effect, the more the amount of the catalyst added exceeds 4.0 moles. The effect does not change, and if less than 0.001 mol, the effect as a catalyst is substantially lost.

Next, a case in which a phosphoric acid aqueous solution is used will be described.
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.

リ ン 酸 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, 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 in the production method of the present invention 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. As a result, a novolak-type phenol resin having a narrow molecular weight distribution and a small amount of unreacted phenols can be efficiently obtained.

When the amount of the phosphoric acid is increased, the effect of obtaining a high yield of a novolak-type phenol resin having a small content of unreacted phenols and a narrow molecular weight distribution tends to be increased. On the other hand, if the amount is more than 1.0 mol, this effect is not substantially changed, so that it 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.

When an organic phosphonic acid or a predetermined amount of a phosphoric acid aqueous solution is used as the acidic catalyst, oxalic acid, sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, or the like may be used in combination with an acidic catalyst usually used in the production of a novolak type phenol resin. It is possible. The combined use of these acidic catalysts is particularly effective in accelerating the reaction in a high molecular region of four or more nuclei, and can be said to be an effective means for controlling the molecular weight distribution.
The novolak-type phenol resin obtained in this manner has a low molecular weight distribution and thus has a low viscosity at the time of melting, and is suitable for washing with a continuous mixing device described later.

製造 Although not particularly limited in the production method of the present invention, usually, after the above reaction, an aqueous phase is separated and removed from the obtained reaction product to obtain a novolak-type phenol resin. Although this method is not particularly limited, it can be usually carried out by leaving it still in a device such as a centrifuge or a separation tower.

Next, in the production method of the present invention, (b) a novolak-type phenol resin (hereinafter sometimes simply referred to as “resin”) in the reaction product obtained in the step (a) is mixed with a continuous mixing apparatus. The step of using and washing with water will be described.
In this step, the resin obtained in the step (a) of reacting a phenol and an aldehyde under an acidic catalyst is washed using a continuous mixing apparatus to remove a catalyst component remaining in the resin. It is.

The method is not particularly limited. For example, resin and water, resin and hot water, resin and steam, or resin and hot water and steam are fed into a continuous mixing device, and the resin and water are mixed in the device. And extracting and removing the acidic catalyst component contained in the resin from the resin phase. Among these, the method of simultaneously sending hot water and steam together with the resin into the continuous mixing apparatus is preferable.
When only water or hot water is fed together with the resin into the continuous mixing device, depending on the properties of the resin, when the resin comes into contact with the water or hot water, the surface of the resin becomes hard and a film is formed. It may be in a state. In such a case, it is practically impossible to wash the catalyst residue in the resin. On the other hand, when only water vapor is used, the volume when condensed into a liquid is small, so that it may be difficult to perform sufficient cleaning. On the other hand, when hot water and steam are used together, the high-temperature steam keeps the resin at a predetermined melt viscosity or less, prevents film formation on the resin surface, and uses a sufficient volume of hot water to form a catalyst component in the resin. Can be efficiently extracted and washed.

The method of simultaneously feeding hot water and steam together with the resin into the continuous mixing apparatus is particularly effective when the reaction product in the step (a) contains a resin having a softening point of 90 ° C. or higher. .
When only hot water is used for washing the resin, it is difficult to raise the internal temperature of the reaction vessel or the like for washing to 100 ° C. or higher, so that a resin having a softening point of 90 ° C. or higher is used. It was difficult to sufficiently clean. For this reason, conventionally, such a resin was washed by dissolving the resin using a solvent such as acetone, but there was a problem that it was necessary to separately remove the used solvent.
In the production method of the present invention, even for such a resin, by simultaneously feeding hot water and steam together with the resin into the continuous mixing apparatus, the efficiency of the resin can be improved similarly to the case where the resin having a low softening point is washed. It can be washed well.

The continuous mixing device used in the production method of the present invention is not particularly limited, and examples thereof include a static mixer and an in-line mixer having a driving unit. All of them continuously send cleaning components such as water, hot water, steam, etc. together with resin (hereinafter, these may be referred to as “cleaning water”), so that both components are introduced from the inlet side to the outlet side in the apparatus. And at the same time, the contact and mixing of the resin and the washing water can be performed.
Among these devices, a static mixer is particularly preferable. This makes it possible to efficiently perform water washing with a simple apparatus configuration without requiring power in the resin washing step. Further, since the static mixer usually has a pressure-resistant structure, it is possible to raise the internal temperature to 100 ° C. or higher using only hot water.

The static mixer used in the production method of the present invention is not particularly limited as long as it has no driving unit and is a device for mixing a plurality of types of fluids. A housing constituted by a housing can be used. The shape of the element is not particularly limited, either. For example, there is a spiral shape in which a rectangular plate is twisted by 180 degrees, and usually, a plurality of these are continuously connected.
In a static mixer, when the fluids to be mixed are compatible with each other, the fluids are homogenized by passing through a housing in which the elements are housed, thereby undergoing operations such as division, conversion, and inversion. Further, even when an incompatible fluid is fed, such as the resin and washing water used in the production method of the present invention, both elements are finely divided by the action of the element, and the area and frequency of contact with each other are sufficiently increased. Can be secured.

In the production method of the present invention, when a static mixer is used, the passage speed of the resin or the like in the static mixer (hereinafter, referred to as “flow velocity”) is not particularly limited, but is preferably higher, and more preferably 1 m / min or more. Particularly preferably, it is 3 m / min or more. This is because the resin and the washing water basically move in a static mixer in an ununiform state without being mixed, so the higher the flow rate, the greater the area and number of contacts between the resin phase and the washing water phase This is because cleaning proceeds efficiently.
The length of the static mixer used is not particularly limited. This is because it depends on the flow rate and the washing temperature when passing the washing mixture and the like. Generally, it is sufficient that the cleaning time can be secured for 1 to 3 minutes. As an example, when the flow rate of the cleaning mixture is 3 m / min and the cleaning is performed at 100 ° C., the length of the static mixer is 3 to 9 m.

In the production method of the present invention, although not particularly limited, it is preferable that the continuous mixing apparatus has a temperature control mechanism. Thereby, the resin can be maintained at a predetermined melt viscosity, and the catalyst residue remaining in the resin can be efficiently washed.
The temperature at which the continuous mixing device is kept warm during washing with water is not particularly limited, but is preferably 70 to 180 ° C. The optimum heat retention temperature depends on the melt viscosity of the resin to be washed. For example, when it is intended to wash a resin having a melt viscosity of 1 Pa · s at 130 ° C. with water, it is preferable that the heat retaining temperature of the continuous mixing device is 160 ° C. or higher.

In the production method of the present invention, the method of charging the resin and the washing water into the continuous mixing apparatus is not particularly limited. For example, there is a method of charging a predetermined amount of each substance using a metering pump or the like.

The resin washed by the continuous mixing device and the water used for washing can be easily separated into a resin phase and an aqueous phase by a centrifuge, a separation tower or the like. Thereby, a resin having a very small content of the catalyst component can be efficiently produced.
As described above, the production method of the present invention is characterized in that a reaction product of a phenol and an aldehyde is washed with water by a continuous mixing device. By using a relatively small amount of washing water, a relatively small amount of washing water can be used in a short time as compared with a conventional method using a batch-type reaction vessel or the like and removing a catalyst component from the resin using a large amount of washing water. Cleaning can be performed and energy costs can be reduced.
In particular, a novolak-type phenol resin obtained by reacting a phenol and an aldehyde with an aqueous solution of an organic phosphonic acid or a predetermined amount of a phosphoric acid has a narrow molecular weight distribution and a low melt viscosity. It is preferred to apply the method.

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”.

(Synthesis of phenolic resin A)
In a 3 L three-necked flask, 1000 parts of phenol and 1000 parts of a 60% aqueous solution of 1-hydroxyethylidene-1,1′-diphosphonic acid (Feriox 115, manufactured by Lion Corporation) were added, and the temperature was raised to 100 ° C. 604 parts of a 37% aqueous formaldehyde solution were sequentially added over 60 minutes, and the mixture was reacted at 100 ° C. while refluxing for 1 hour. Thereafter, the reaction vessel was allowed to stand, separated into a resin phase and a catalyst phase, and the lower catalyst layer was separated and removed to obtain 1181 parts of phenol resin A.
The obtained phenolic resin A had a softening point of 63 ° C. and a melt viscosity of 0.1 Pa · s at 80 ° C. When the phosphorus element of this resin was measured by fluorescent X-ray, it was 4000 ppm. This phosphorus element is the one in which the organic phosphonic acid as a catalyst remains.

(Example 1)
1000 parts of phenolic resin A was inserted into the container 1. A stationary mixer having a length of 5 m and a structure capable of controlling the temperature with steam was connected to the lower portion of the container 1 via an open / close cock. The temperature inside the container was kept at 80 ° C. The stationary mixer was set so that hot water could be injected through an openable cock. Hot water was injected by a metering pump. The outlet of the static mixer was connected to the upper part of the separation tower 2 via an open / close cock. The static mixer was kept at 150 ° C. Hot water of 90 ° C. was injected into the static mixer at a rate of 600 ml / min by a metering pump, and the inside of the container 1 was pressurized with air to 0.2 MPa, and the lower cock of the apparatus 1 was fully opened. Phenol resin A was pressure-fed to separation tower 2 while being mixed with hot water in a static mixer. At this time, the air pressure was adjusted so that the pressure in the apparatus 1 was maintained at 0.2 MPa. The opening of the cock on the upper part of the separation tower 2 was adjusted so that the time required for the mixture to pass through the static mixer was 2 minutes. After transferring the entire amount of the phenol resin A, the mixture was allowed to stand for 10 minutes, and the lower resin phase was extracted from the separation tower 2.
The phosphorus content of the obtained washed phenol resin was 190 ppm as measured by fluorescent X-ray. The time required for washing was 20 minutes including the time for standing in the separation tower.

(Comparative Example 1)
In a 3 L three-necked flask, 1000 parts of phenol resin A and 1000 parts of water were added, the temperature was raised to 100 ° C., and washing was performed while refluxing at 100 ° C. for 1 hour. After the stirring was stopped, the mixture was allowed to stand for 15 minutes to extract the lower resin phase. The phosphorus content of the obtained washed phenol resin was 200 ppm as measured by fluorescent X-ray. The time required for the cleaning was 100 minutes including the temperature raising time and the standing time.

(Comparative Example 2)
The resin was washed in the same manner as in Comparative Example 1 except that the reflux / washing time at 100 ° C. was 10 minutes. The time required for washing was 50 minutes. The phosphorus content of the obtained washed phenol resin was 480 ppm as measured by fluorescent X-ray.

(Synthesis of phenolic resin B)
In a 3 L three-necked flask, 1000 parts of phenol and 1000 parts of a 50% aqueous solution of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC, manufactured by Johoku Chemical Co., Ltd.) were added, and the temperature was raised to 100 ° C. 690 parts of a 1% aqueous formaldehyde solution were sequentially added over 60 minutes, and the mixture was reacted at 100 ° C. for 1 hour under reflux. Thereafter, the reaction vessel was allowed to stand, separated into a resin phase and a catalyst phase, and the lower catalyst layer was separated and removed to obtain 1192 parts of phenol resin B.
The obtained phenolic resin B had a softening point of 92 ° C. and a melt viscosity of 1 Pa · s at 130 ° C. When the phosphorus element of this resin was measured by fluorescent X-ray, it was 4200 ppm.

(Example 2)
1000 parts of phenolic resin B was inserted into the container 1. A stationary mixer having a length of 5 m and a structure capable of controlling the temperature with steam was connected to the lower portion of the container 1 via an open / close cock. The temperature inside the container was kept at 130 ° C. The static mixer was set so that hot water and steam could be injected through an openable cock. Hot water was injected by a metering pump. Steam at a predetermined pressure can be injected by a pressure regulating valve. The outlet of the static mixer was connected to the upper part of the separation tower 2 via an open / close cock. The static mixer was kept at 165 ° C. Hot water of 90 ° C. is injected into the static mixer at a rate of 600 ml / min by a metering pump, and steam of 0.2 MPa is further injected, and the inside of the container 1 is pressurized with air to 0.2 MPa. The lower cock was fully opened. Phenol resin A was pressure-fed to separation tower 2 while being mixed with hot water in a static mixer. At this time, the air pressure was adjusted so that the pressure in the apparatus 1 was maintained at 0.2 MPa. The opening of the cock on the upper part of the separation tower 2 was adjusted so that the time required for the mixture to pass through the static mixer was 2 minutes. After transferring the entire amount of the phenol resin B, the mixture was allowed to stand for 10 minutes, and the lower resin phase was extracted from the separation tower.
The phosphorus content of the obtained washed phenol resin was 200 ppm as measured by fluorescent X-ray. The time required for washing was 20 minutes including the time for standing in the separation tower.

(Comparative Example 3)
In a 3 L three-necked flask, 1000 parts of phenolic resin B and 1000 parts of water were added, the temperature was raised to 100 ° C., and washing was performed while refluxing at 100 ° C. for 1 hour. After the stirring was stopped, the mixture was allowed to stand for 15 minutes to extract the lower resin phase. The phosphorus content of the obtained washed phenol resin was 280 ppm as measured by fluorescent X-ray. The time required for the cleaning was 100 minutes including the temperature raising time and the standing time.

(Comparative Example 4)
The procedure was performed in the same manner as in Comparative Example 3 except that the reflux / washing time was changed to 10 minutes. The time required for washing was 50 minutes, and the phosphorus content of the obtained washed phenol resin was 760 ppm as measured by fluorescent X-ray.

(Synthesis of phenolic resin C)
In a 3 L three-necked flask, 1000 parts of phenol and 1 part of p-toluenesulfonic acid are added, the temperature is raised to 100 ° C., 647 parts of a 37% aqueous formaldehyde solution are sequentially added over 60 minutes, and the mixture is refluxed at 100 ° C. for 1 hour. The reaction was carried out while allowing 1648 parts of phenol resin C to be obtained. Since the resin at this point contained unreacted phenol and water, the softening point and melt viscosity were not measured. When the sulfur element of this resin was measured by fluorescent X-ray, it was 200 ppm. Thereafter, the resin was washed and the unreacted phenol was removed to 2%, and the softening point of the resin was 105 ° C.

(Example 3)
1000 parts of phenolic resin C was inserted into the container 1 and the resin was washed in the same manner as in Example 2. After transferring the entire amount of the phenol resin C, the mixture was allowed to stand for 10 minutes, and the lower resin phase was extracted from the separation tower.
The sulfur content of the obtained washed phenol resin was 20 ppm as measured by fluorescent X-ray. The time required for washing was 20 minutes including the time for standing in the separation tower. This sulfur element is one in which p-toluenesulfonic acid as a catalyst remains.

(Comparative Example 5)
In a 3 L three-necked flask, 1000 parts of phenol resin C, 500 parts of methyl ethyl ketone, and 1000 parts of water were added, the temperature was raised to 80 ° C., and washing was performed at 80 ° C. for 15 minutes. After the stirring was stopped, the mixture was allowed to stand for 15 minutes, and the lower aqueous phase was extracted. This operation was repeated three times for washing. Thereafter, the solvent in the flask was removed by solvent dehydration under normal pressure. The sulfur content of the obtained washed phenol resin was 20 ppm as measured by fluorescent X-ray. The time required for the washing was 180 minutes including the time for raising the temperature, the time for standing still, and the time for removing the solvent.

(Comparative Example 6)
The procedure was performed in the same manner as in Comparative Example 5 except that the number of times of washing was one. The time required for washing was 110 minutes, and the sulfur content of the obtained washed phenol resin was 60 ppm as measured by fluorescent X-ray.

(Synthesis of phenolic resin D)
In a 3 L three-necked flask, 1000 parts of phenol and 1000 parts of an 85% aqueous phosphoric acid solution are added, the temperature is raised to 100 ° C., 604 parts of a 37% aqueous formaldehyde solution are sequentially added over 60 minutes, and the mixture is refluxed at 100 ° C. for 1 hour. The reaction was continued. Thereafter, the reaction vessel was allowed to stand, separated into a resin phase and a catalyst phase, and the lower catalyst layer was separated and removed to obtain 1183 parts of phenol resin D.
The obtained phenolic resin D had a softening point of 64 ° C. and a melt viscosity of 0.1 Pa · s at 80 ° C. When the phosphorus element of this resin was measured by fluorescent X-ray, it was 5000 ppm. This phosphorus element is the one in which phosphoric acid as a catalyst remains.

(Example 4)
Phenol resin D1000 parts was inserted into the container 1. A stationary mixer having a length of 5 m and a structure capable of controlling the temperature with steam was connected to the lower portion of the container 1 via an open / close cock. The temperature inside the container was kept at 80 ° C. The stationary mixer was set so that hot water could be injected through an openable cock. Hot water was injected by a metering pump. The outlet of the static mixer was connected to the upper part of the separation tower 2 via an open / close cock. The static mixer was kept at 150 ° C. Hot water of 90 ° C. was injected into the static mixer at a rate of 600 ml / min by a metering pump, and the inside of the container 1 was pressurized with air to 0.2 MPa, and the lower cock of the apparatus 1 was fully opened. Phenol resin D was fed into separation tower 2 while being mixed with hot water in a static mixer. At this time, the air pressure was adjusted so that the pressure in the apparatus 1 was maintained at 0.2 MPa. The opening of the cock on the upper part of the separation tower 2 was adjusted so that the time required for the mixture to pass through the static mixer was 2 minutes. After transferring the entire amount of the phenol resin D, the mixture was allowed to stand for 10 minutes, and the lower resin phase was extracted from the separation tower.
The phosphorus content of the obtained washed phenol resin was 210 ppm as measured by fluorescent X-ray. The time required for washing was 20 minutes including the time for standing in the separation tower.

(Comparative Example 7)
In a 3 L three-necked flask, 1000 parts of phenol resin D and 1000 parts of water were added, the temperature was raised to 100 ° C., and washing was performed while refluxing at 100 ° C. for 1 hour. After the stirring was stopped, the mixture was allowed to stand for 15 minutes to extract the lower resin phase. The phosphorus content of the obtained washed phenol resin D was 250 ppm as measured by fluorescent X-ray. The time required for the cleaning was 100 minutes including the temperature raising time and the standing time.

(Comparative Example 8)
The resin was washed in the same manner as in Comparative Example 7, except that the reflux / washing time at 100 ° C. was changed to 10 minutes. The time required for washing was 50 minutes. The phosphorus content of the obtained washed phenol resin D was 500 ppm as measured by fluorescent X-ray.

Table 1 shows the amount of residual catalyst (phosphorous or sulfur) and the washing time for the phenolic resins obtained in Examples 1 to 4 and Comparative Examples 1 to 8.

(Measuring method)
1. Softening point: Measured according to JIS K2531.
2. Melt viscosity: Measured with a cone and plate viscometer.
3. X-ray fluorescence: Measured by JSX-3211 element analyzer manufactured by JEOL. The amount of the catalyst was determined by measuring a sample with a known concentration and calculating by a fundamental parameter method.

Examples 1 to 4 are production methods of the present invention in which a novolak-type phenol resin obtained by reacting a phenol and an aldehyde in the presence of an acidic catalyst was washed using a continuous mixing apparatus. It can be seen that the catalyst residue can be efficiently cleaned in a short time as compared with the comparative example in which cleaning is performed by the conventional method.

The present invention provides a novolak-type phenol characterized in that a novolak-type phenol resin in a reaction product obtained in a step of reacting a phenol and an aldehyde under an acidic catalyst is washed with water using a continuous mixing apparatus. It is a method for producing a resin, which provides a method suitable for efficiently and efficiently washing and removing an acidic catalyst, particularly an organic phosphonic acid catalyst and a phosphoric acid catalyst, remaining in a novolak-type phenol resin with water.

Claims (8)

In the method for producing a novolak type phenol resin,
(A) reacting a phenol with an aldehyde under an acidic catalyst;
(B) washing the novolak-type phenol resin in the reaction product obtained in the step (a) with a continuous mixing device,
A method for producing a novolak-type phenol resin, comprising: The method for producing a novolak-type phenolic resin according to claim 1, wherein the reaction product contains a novolak-type phenolic resin having a softening point of 90 ° C or higher. The method for producing a novolak-type phenolic resin according to claim 1 or 2, wherein, in the step (b), hot water and steam are simultaneously fed into the continuous mixing device together with the novolak-type phenolic resin. The method for producing a novolak-type phenolic resin according to any one of claims 1 to 3, wherein in the step (b), the continuous mixing device is a static mixer. The method for producing a novolak-type phenol resin according to any one of claims 1 to 4, wherein in the step (a), the acidic catalyst is an organic phosphonic acid. The method for producing a novolak-type phenol resin according to claim 5, 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 novolak-type phenol resin according to any one of claims 1 to 4, wherein in the step (a), the acidic catalyst is a phosphoric acid aqueous solution, and the phosphoric acid is used in an amount of 0.2 mol or more per 1 mol of the phenol. Manufacturing method. The method for producing a novolak-type phenolic resin according to claim 7, wherein the phosphoric acid is phosphoric acid.