JPH10298257A - Production of novolak phenol resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high-ortho-type high-mol.-wt. novolak phenol resin sol. in a solvent and hardly contg. ionic impurities, safely in a short time and in a high yield. SOLUTION: In the polycondensation of a phenol and an aldehyde in an appropriate molar ratio, the phenol is heated to 160 deg.C or higher in a high- pressure reactor 2 equipped with a set of two turbine-type stirring blades 1 having the same diameters and installed up and down; then formaline contg. 200 ppm or lower formic acid or a paraformaldehyde-pehnol mixture contg. 80% or higher paraformaldehyde is successively added to and reacted with the phenol in the state of being pressurized to 0.5 MPa or higher with an inert gas; and the reaction mixture is subjected to further polymn. at 200-250 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novolak-type phenolic resin, and more particularly to a high-molecular weight phenolic resin having extremely low ionic impurities and highly ortho-ortho-bonding and being soluble in a solvent. Efficiently produces novolak-type phenolic resin with excellent curability, heat resistance and electrical properties, suitable for molding materials, epoxy resin curing agents, photoresist resins, carbon resin base resins, thermoplastic resin modifiers, etc. It is about the method.

[0002]

2. Description of the Related Art A general method for producing a novolak type phenol resin is as follows. A phenol and an aldehyde are used as a catalyst with a known organic acid and / or an inorganic acid as a catalyst at normal pressure of 100.degree.
Is known for performing an addition condensation reaction for several hours, followed by dehydration and removal of unreacted monomers. The novolak-type phenolic resin produced by such a method has many para-position bonds to the ortho-position methylene bond of phenols. The curability was inferior to that of novolak.

On the other hand, conventionally, industrial production of high orthonovolacs is carried out directly or after adding phenols and aldehydes under weak acidity with a metal salt catalyst such as zinc acetate, lead acetate and zinc naphthenate under weak acidity. Further, a method is generally employed in which a condensation reaction is carried out while adding an acid catalyst while dehydrating, and a step for removing unreacted substances is further provided as necessary (for example, JP-A-55-90523, JP-A-59-8041).
No. 8, JP-A-62-230815), but in such a method, there is a problem in productivity that the reaction and dehydration steps take time, and metal ions are contained in the resin,
The cured product is inferior in properties such as heat resistance, water resistance, and electrical insulation, and has a problem that it cannot be used particularly for applications in the electric and electronic fields where ionic impurities are rejected.

In the case where trifunctional phenols are used as phenols, the reactivity decreases when novolak molecules are polymerized to a certain degree, and the weight average molecular weight of the novolak type phenol resin obtained by the above-mentioned production method is at most 15%. ,
When the ratio of aldehydes to phenols (hereinafter, referred to as a molar ratio) is increased in order to obtain a high molecular weight resin of more than 2,000, gelation is likely to occur, resulting in an insoluble and infusible state. Are known.

As a high molecular weight resin using trifunctional phenols, a method of producing phenols by adding phenols to a large excess of hydrochloric acid and formaldehyde (for example, Japanese Patent Application Laid-Open No.
This resin has a methylol group, is not a novolak-type phenol resin in a strict sense, and has a part or all of a solvent-insoluble portion.

Examples of high molecular weight novolak type phenol resins include those using bifunctional phenols as phenols, for example, orthocresol, paracresol, paranonylphenol, paratertiary butylphenol (for example, Narazaki: Koka, 66, 392 (1963), JP-A-50-136393 and JP-A-56-9290.
No. 8, JP-A-56-103215, JP-A-5-103215
No. 7-187311, JP-A-60-260611, JP-A-61-12714, etc.), but a resin using a bifunctional phenol cannot be completely cured thereafter. There is a problem.

[0007] As a method for producing a high orthonovolak for reducing ionic impurities, there is a method for producing a high orthonovolak using a catalyst other than a metal salt. When a phenol and an aldehyde are reacted, a catalyst other than a metal salt catalyst is used. For example, an acid that undergoes sublimation decomposition such as oxalic acid and a non-polar solvent are added, and the water and the solvent are evaporated at a temperature of 110 ° C. or higher, and the primary reaction is performed for 2 to 10 while returning only the solvent to the reaction system.
A method of performing the secondary reaction for 1 to 10 hours is known (for example, Japanese Patent Application Laid-Open No. H4-220212). However, such a method is not only for increasing the reaction time but also for reducing ionic impurities. However, there is a problem that not only a step of raising and decomposing a catalyst is required, but also a step of removing a nonpolar solvent is required.

Further, as a method for producing a high orthonovolac without using a catalyst, a phenol and paraformaldehyde are mixed in a large amount using a non-polar solvent such as xylene, and then mixed.
A method in which the reaction is carried out in a pressurized vessel at 00 to 220 ° C. for 12 to 20 hours (for example, Casiraghi et al., Makromol. Chem. 182,
(11), 2973, 1981 and JP-A-6-34583.
No. 7 publication) is known. In particular, the Makromol. Chem.
Although the process described in the publication states that a resin having a very high ratio of methylene bonds at the ortho position can be obtained, the weight-average molecular weight of the obtained resin is at most 40,000, while these processes are used. As mentioned in the literature, the reaction takes a long time, and when the reaction temperature is increased, the aldehydes are present in a predetermined amount from the beginning and react at once, and if the reaction pressure cannot be controlled, There is the problem mentioned above, and as a common feature of the method using a non-polar solvent,
Since there are problems such as the necessity of a solvent removal process, safety in handling, and the inability to increase the yield per batch in the case of batch production, industrial high ortho-type novolak phenolic resin It is not always suitable as a manufacturing method.

[0009]

The present inventors have made intensive studies to overcome these problems, and as a result, successively inject aldehydes into phenols heated and pressurized in a reactor without using a catalyst. Mix, polymerize by high temperature reaction, dehydration step, preferably remove low nuclei with an appropriate solvent, and further use paraformaldehyde mixed with formalin or phenols with reduced formic acid as aldehydes By using a reactor having two-stage turbine-type stirring blades of the same diameter as necessary, it is suitable for molding materials for the electric and electronic fields, for curing agents for epoxy resins, for laminated boards, and other wide applications. Highly ortho-type novolak with high solubility in solvent despite having high molecular weight with excellent water resistance, heat resistance and electrical insulation. A phenolic resin, found to be able to produce good easy and very efficient security on the reaction, and have reached the present invention.

[0010]

According to the present invention, when a phenol and an aldehyde are reacted without using a catalyst, the phenol is heated to 160 ° C. or more while being pressurized to 0.5 MPa or more with an inert gas in advance. A method for producing a novolak-type phenolic resin, which comprises heating and sequentially adding aldehydes to carry out an addition condensation reaction while maintaining the reaction temperature at 160 ° C. or higher, and polymerizing while dehydrating at 200 ° C. or higher. Preferably, a low molecular weight is removed by using a suitable solvent, more preferably, aldehydes are added from the lower part of the reactor, and formalin or a purity of 80 or less is preferably used as aldehydes, in which formic acid is removed to 200 PPM or less. % Or more paraformaldehyde dissolved or suspended in phenol, and used as a reactor A process for producing a phenolic novolak resin characterized by using as or similar reactor having a turbine type agitating blades of the second stage a combination of static mixer.

Although the phenols are not particularly limited,
The value of the present invention is effectively exerted when using functional phenols. Examples of the trifunctional phenols include one or more compounds having a phenolic hydroxyl group, such as phenol and meta-cresol, and having no substituent other than at least the meta position with respect to the phenolic hydroxyl group. The phenols are heated in the reactor to 160 ° C. or higher, preferably 180 to 200 ° C., and pressurized to 0.5 MPa or higher, preferably 0.7 MPa or higher by a known inert gas such as nitrogen gas.

When the initial heating temperature of the phenol is 160 ° C. or lower, not only the reaction rate at the start of the addition of the aldehyde becomes slow, but also the para-methylene bond is promoted, making it difficult to obtain the desired resin. The initial pressurization with an inert gas, of course, includes the meaning of preventing oxidative discoloration, but it is intended to prevent the reaction temperature from decreasing due to latent heat of vaporization of condensed water generated in the raw materials and the condensation reaction.
When the pressure is 0.5 MPa or less, the reaction temperature immediately after the start of the reaction decreases, and the target temperature cannot be maintained.

Next, the aldehydes are successively added into the reactor, preferably from the lower part of the reactor. The molar ratio of aldehydes to phenols is 0.50
The range is 0.85, preferably 0.7 to 0.8, and more preferably 0.73 to 0.80. Molar ratio 0.5
When the molecular weight is less than 0, a sufficient high molecular weight region cannot be obtained even in a polymerizing step to be described later, and the yield is reduced.
If it is 5 or more, it is difficult to control the molecular weight in the polymerization step, and the formation of gelled or partially gelled products is promoted.

The aldehydes used in the present invention include one or more aldehydes having an aldehyde group such as formaldehyde, paraformaldehyde and polyoxymethylene. One of them is preferably a known ion exchange resin. And formalin having a formic acid content of 200 PPM or less, and paraformaldehyde having a purity of 80% or more. Formalin refers to an aqueous formaldehyde solution, but it is preferable to use one having a concentration of 37% or more, more preferably 40% or more. Formaldehyde easily generates formic acid during the production and storage of formalin by the Cannizzaro reaction, but this formic acid contains not only ionic impurities that cannot be completely decomposed in the formed resin, but also the addition condensation of phenols and aldehydes. Since it acts as an acid catalyst during the reaction and promotes the para-methylene bond,
It is necessary to remove it to not more than PM, more preferably not more than 50 PPM.

Paraformaldehyde has a purity of 80%
It is preferable to use the above. If the purity is low, the degree of ortho-position methylene bond decreases, which is not preferable. Also, since paraformaldehyde is generally a solid substance, and it is difficult to sequentially add it from a heated phenol liquid, in the present invention, a part of paraformaldehyde and phenol are previously mixed and dissolved, It is essential to keep it in a slurry state. The mixing ratio of paraformaldehyde and phenols is not particularly limited, but is preferably a ratio that can ensure fluidity that can be handled by a known high-pressure pump or slurry pump. In this case, the amount of phenol required for mixing paraformaldehyde is regarded as a part of the phenol heated in the reactor, and the molar ratio and the like are calculated.

In the successive addition of aldehydes, known high-pressure pumps such as plunger type and diaphragm type, single-shaft eccentric screw pumps of rotary displacement type (for example, Mono pump manufactured by Hyojin Kiki Co., Ltd.), and slurry pumps such as tube pumps And preferably supplied quantitatively into the heated phenols from the lower part of the reactor. The rate of addition at this time is 15 minutes to 2 minutes as long as the reaction temperature is maintained at 160 to 200 ° C. and a sufficient addition condensation reaction is performed, and excessive reaction heat generation and excessive pressure rise due to abrupt reaction do not occur.
It is preferable to set the addition time.However, due to the fluctuation of the heat exchange condition due to the contamination of the heat transfer surface of the reactor and other sudden factors from the outside, the addition of the aldehydes and the adjustment of the addition speed can reduce the temperature. It is also a feature of the present invention that safety can be ensured and production can be stabilized immediately in the above reaction.

The aldehydes may be added from the upper part of the general reactor or the phenols at the liquid level. However, there are problems such as odor in the pressure reduction step, yield, and stability of the obtained molecular weight. Addition from the lower part of the reactor, which is excellent in terms of aspect, is particularly preferred. Aldehydes injected from the bottom of the reactor react immediately and at the same time partially evaporate from the upper part of the reaction liquid to complete the addition condensation reaction. Formaldehyde with a low vapor pressure is vaporized on the liquid surface of the phenols, and stays in the gas phase of the reactor, and cannot react sufficiently.
Alternatively, partial reaction promotion at the gas-liquid interface occurs, making it difficult to control the molecular weight.

The reactor used in the present invention is a general pressure reactor, and has two stages of turbine-type stirring blades having the same diameter which are installed vertically so as to be advantageous for adding aldehydes to the lower portion of the reactor. And more preferred. Aldehydes added from the lower part of the reactor react immediately, but partly evaporate and rise in the liquid. At this time, by using two stages of the same diameter turbine type stirring blades, the respective stirring flows collide at an intermediate position between the upper and lower turbine type stirring blades to form a stagnation zone. As a result, the amount of aldehyde gas in the gas phase also decreases, which is suitable for controlling the molecular weight and for odor problems. On the other hand, in the case of one turbine blade or other large-sized stirring blades that generate a stirring flow in the vertical direction, the reaction efficiency of aldehydes is poor, a predetermined molecular weight cannot be obtained, and the yield decreases.

After the addition of the aldehyde to the phenol and the addition condensation reaction, the temperature and pressure are further maintained for several minutes to several hours after completion of the addition of the aldehyde, and it is confirmed that no self-heating occurs. Raise the temperature to 250 ° C. While maintaining this temperature range, dehydration is performed by flashing while lowering the pressure through a heat exchanger attached to the reactor, and the polymerization reaction proceeds to obtain a target resin. At this time, with the dehydration and the removal of some unreacted monomers, the reaction liquid rapidly increases in viscosity, and when the reaction temperature becomes 200 ° C. or lower, there is a risk of solidification in the reactor. If the temperature is higher than 250 ° C., the polymerization reaction cannot be controlled, resulting in gelation.

There is no problem if the above steps are carried out in the same reactor. However, in order to prevent a decrease in stirring efficiency and a decrease in heat transfer efficiency due to a change in viscosity, the addition of aldehydes is completed and self-heating occurs. When it was confirmed that the reaction did not occur, the polymer was supplied to the static mixer reactor from the lower part of the reactor, transferred to the next reactor or a flash container such as a flash tank while raising the temperature to 200 to 250 ° C. The method of proceeding the chemical reaction is preferred.

The static mixer used in the present invention has a mixing blade such as a twisting blade (FIG. 2) or a folded blade (FIG. 3) inside the pipe, and when the fluid passes through the inside, the fluid is repeatedly divided. Are mixed. In addition, it is preferable that these static mixers be double tubes and be capable of heating and cooling from the outside, and in order to further enhance the heating and cooling effect, a multi-tube using a static mixer in combination with a tube of a multi-tube heat exchanger is used. A heat exchanger type mixer may be used. The type of the static mixer and the heat exchanger type mixer are not particularly limited, but those having two or more blades are preferable in view of the mixing effect, and there is no problem if they are used in combination as necessary. The diameter and length of the reaction pipe including the static mixer and / or the multi-tube heat exchanger type mixer vary depending on the target throughput, but the reaction at the static mixer outlet at the end of the reaction is preferred. The pipe diameter is such that the liquid flow rate can secure 0.05 m / sec or more.

The flow rate of the reaction solution at the exit of the static mixer at the end of the reaction represents the overall flow rate. When the flow rate is low, the mixing effect and the heat transfer effect are reduced. At 0.05 m / sec or less, the reaction becomes non-uniform, and in the worst case, it is partially polymerized to produce a gel. In addition, insoluble and infusible scale is easily generated on the heat transfer surface. The pressure is controlled at the outlet of the static mixer, and the reaction solution whose reaction temperature is maintained at 200 to 250 ° C. is further supplied to a flash vessel, and the pressure is returned to normal pressure and the water is continuously removed. Further, if necessary, the unreacted monomer is removed by heating under reduced pressure or using a known thin film evaporator or the like.
A high ortho-type novolak phenolic resin having a molecular weight of 000 or more and having very few ionic impurities is obtained.

After completely dissolving this resin in a solvent, pure water was added thereto with stirring to precipitate and take out the resin.
By removing the solvent, a weight average molecular weight of 100,00
A novolak-type phenol resin of 0 or more is obtained. As the solvent used at this time, one or a mixture of two or more of ketones such as acetone and methyl ethyl ketone, alcohols such as methanol and ethanol, tetrahydrofuran, and N, N-dimethylformamide having high solubility in water are used. Preferably, 100 to 1000 parts by weight of the novolak type phenol resin is dissolved. 10 solvents
If the amount is less than 0 part by weight, the dissolving step is difficult, and the viscosity of the obtained solution is high, so that it is difficult to add and mix pure water in the next step, and if the amount is more than 1000 parts by weight, the yield decreases.

Next, pure water is added to the solution. The pure water used here has an electric conductivity of 1 μS / cm.
The following are preferable, and 1/10 to an equivalent amount of the solvent used is added under stirring to precipitate the resin. If the amount of pure water to be added is less than 1/10 of the amount of the solvent used, the resin will not sufficiently precipitate, and if the amount is equal to or more than the amount of the solvent, the target low molecular nucleus cannot be removed. If the solution after the addition of pure water is left as it is, it is separated into two or three layers. In this state, the desired lowermost layer may be removed, and a known centrifugal separator may be kept in a suspended state. The separation may be performed using a filtration device such as a filter press or a filter press. This operation is 1
There is no problem if you go twice or more times.

Thereafter, the solvent may be removed by a reduced pressure drier, or the solvent may be evaporated again by heating and melting, or the solvent may be removed by using a known thin film evaporator to obtain the desired resin. The content of the unreacted monomer in the novolak type phenol resin obtained in the present invention is not particularly limited, but is generally 10% or less, preferably 5% or less, more preferably 1% or less. When the content of unreacted monomer is high, not only environmental hygiene such as odor when handling the resin, but also a decrease in mechanical strength when cured, a decrease in moisture resistance, a decrease in dimensional stability, Alternatively, there is a possibility that a problem such as a decrease in carbon yield when carbonized may occur.

Further, a specific example of the present invention will be described with reference to FIG. 1, but the present invention is not limited by the description. FIG. 1 is a schematic diagram showing the equipment and flow of the present invention. Phenols are put into a high-pressure reactor (2) equipped with upper and lower two-stage turbine-type stirring blades (1), and then heated to 160 ° C. or more, and an inert gas such as nitrogen gas is supplied to a pressure line (3). To 0.5 MPa or more. After reaching the predetermined temperature and pressure, the amount of aldehyde necessary to obtain the target molecular weight is injected and added from the injection nozzle (5) at the lower part of the reactor by the high-pressure metering pump (4). While the injected aldehyde rises to the liquid level, an addition condensation reaction is performed with the phenol kept at a reaction temperature of 160 to 200 ° C. or higher. After completion of the addition of the aldehydes, it was confirmed that no self-heating occurred. Then, the take-off valve (6) at the lower part of the reactor was gradually opened, and the mixture was supplied to the static mixer (7, 8, 9) and flushed while heating with a heating medium. Supply to container. At this time, while controlling the pressure by the pressure regulating valve (10), the temperature of the reaction solution in the static mixer is maintained at 200 to 250 ° C., and the polymerization reaction proceeds.

The water contained in the resin evaporates immediately at the inlet of the flash container (11), is condensed by the heat exchanger (12) and removed outside the system, and only the dehydrated novolak type phenol resin is removed from the flash container (11). The flash container is heated so that the resin does not solidify. Thereafter, the inside of the reactor is further reduced in pressure and further heated to remove unreacted monomers, taken out of the reactor and solidified by cooling to obtain a solid high ortho-type novolak phenol resin having a high molecular weight and extremely few ionic impurities. Can be

[0028]

The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited by these examples. It should be noted that all “%” described in the text indicate “% by weight”.

Example 1 22.0 kg of phenol was heated to 180 ° C. in a high-pressure reactor having a capacity of 50 L having a heat exchanger, a heating device and a two-stage turbine type stirring blade of the same diameter,
After pressurizing to 0.7 MPa with nitrogen gas, 13.1 kg of 40% formalin in which formic acid content was reduced to 50 PPM by ion exchange resin treatment in advance by a diaphragm type high-pressure metering pump was applied over 60 minutes from the bottom of the reactor. Sequential addition was carried out to cause an addition condensation reaction. During this time, the reaction temperature is 180 ~
The temperature of the jacket of the reactor and the rate of addition were adjusted to 200 ° C. After the addition, the temperature was maintained for 5 minutes to confirm that self-heating did not occur.
The dehydration reaction was performed while heating to maintain 0 ° C. and returning to normal pressure over 30 minutes via a heat exchanger. Thereafter, the pressure was reduced to 1.3 KPa, and the unreacted phenol was removed for 30 minutes, and taken out on a cooling vat to obtain 20.0 Kg of a solid novolak phenol resin. Table 1 shows the properties of the obtained resin. FIG. 4 shows a molecular weight distribution chart measured by gel permission chromatography (hereinafter, referred to as GPC).

Example 2 Phenol 20.
Add 0 kg, and use 8.1 kg of 88% paraformaldehyde as an aldehyde. Further, paraformaldehyde was previously mixed with 8.0 kg of phenol, and the suspension was converted to a suspension using a plunger-type high-pressure metering pump. A novolak-type phenol resin (27.0 kg) was obtained in the same manner as in Example 1, except that the phenol was supplied from the lower part of the reactor and unreacted phenol was not removed under reduced pressure. Table 1 shows the properties of the obtained resin. FIG. 5 shows a molecular weight distribution chart by GPC.

Example 3 20.0 kg of the novolak type phenol resin obtained in Example 2 was mixed with 50.0 K of acetone.
g, dissolve in a liquid temperature of 30 ° C., add 10.0 kg of pure water over 10 minutes, mix for 5 minutes, filter using a filter cloth, and treat the residue with a vacuum dryer for 2 hours. The solvent was removed to obtain 12.5 kg of a solid novolak type phenol resin. Table 1 shows the properties of the obtained resin. FIG. 6 shows a molecular weight distribution chart by GPC.

Example 4 Except that 20.0 kg of meta-cresol as phenol was put into a reactor and a mixture of 7.1 kg of 88% paraformaldehyde and 10.0 kg of meta-cresol was supplied from the lower part of the reactor. Was obtained in the same manner as in Example 1 to obtain 30.0 kg of novolak-type cresol resin. Table 1 shows the properties of the obtained resin. FIG. 7 shows a molecular weight distribution chart by GPC.

Example 5 20.0 kg of the novolak type cresol resin obtained in Example 4 was mixed with 40.0 K of acetone.
g of tetrahydrofuran and 10.0 kg of tetrahydrofuran were dissolved in the same manner as in Example 3 to obtain 12.0 kg of a solid novolak-type cresol resin.

Example 6 The procedure was the same as in Example 1 until the addition of the aldehyde was completed. After confirming that there was no self-heating, the inner diameter was 10 mm with a twisting blade inside, and the total length was 1500.
The mixture was fed to a 0 mm double-tube primary stationary mixer, and then the reaction solution was internally 8 mm in diameter with a twisted blade and had a total length of 1 mm.
After passing through a multi-tube heat exchanger type mixer composed of seven 860 mm static mixers, additional condensation is performed in a secondary static mixer and a tertiary static mixer having the same structure as the primary static mixer. The reaction was allowed. During this time, pressure adjustment and heating adjustment of the static mixer and the multi-tube heat exchanger mixer were performed so that the reaction temperature was 200 to 220 ° C. The reaction solution was continuously supplied to a flash vessel and dehydrated. After that, the pressure in the flash vessel was reduced to 1.3 KPa, and the unreacted phenol was removed for 30 minutes.
0 Kg was obtained. Under these conditions, the reaction time by passing through the static mixer was 2 minutes and 18 seconds, and the flow rate of the reaction solution at the outlet of the final mixer was 0.13 m / sec. Table 1 shows the properties of the obtained resin.

EXAMPLE 7 20.0 kg of meta-cresol as a phenol was placed in a reactor, and a mixture of 7.1 kg of 88% paraformaldehyde and 10.0 kg of meta-cresol was supplied from the lower part of the reactor. Was obtained in the same manner as in Example 6 to obtain 27.0 kg of novolak-type cresol resin. Table 1 shows the properties of the obtained resin.

Example 8 The procedure of Example 1 was repeated, except that 40% formalin was added to the liquid level from the upper part of the reactor, and 18.0 kg of novolak phenol resin was used.
I got Table 1 shows the properties of the obtained resin.

Example 9 Example 1 except that a general 40% formalin having a formic acid concentration of 400 PPM was used.
Novolak phenolic resin 2
2.0 kg was obtained. Table 1 shows the properties of the obtained resin.

Comparative Example 1 22.0 kg of phenol and 0.22 kg of oxalic acid, a typical novolacation catalyst, were charged into the reactor used in Example 1 and heated to 100 ° C. at normal pressure, and then 40% After 13.1 kg of formalin was gradually added over 90 minutes, the reaction was continued for 60 minutes while maintaining the temperature at 100 ° C. Further, after dehydrating the resin while heating it to 130 ° C. at normal temperature, the pressure was reduced to 1.3 KPa, and unreacted phenol was removed until the reaction solution temperature reached 180 ° C.
It was taken out into a cooling vat to obtain 21.0 kg of a novolak type phenol resin. Table 1 shows the properties of the obtained resin.
Shown in

<< Comparative Example 2 >> The amount of 40% formalin was changed to 1
A novolak-type phenol resin (23.0 kg) was obtained in the same manner as in Comparative Example 1 except that the amount was 4.7 kg. Table 1 shows the properties of the obtained resin. FIG. 8 shows a molecular weight distribution chart by GPC.

Comparative Example 3 The reactor used in Example 1 was charged with 22.0 kg of phenol, 4.8 kg of 88% paraformaldehyde, and 0.22 kg of zinc acetate which is a representative of a divalent metal salt as a high orthonovolacation catalyst. It was placed,
The mixture was heated to 100 ° C. under normal pressure, and the reaction was continued for 3 hours while maintaining the temperature at 100 ° C. Then, the mixture was cooled to 90 ° C., and then 0.11 kg of oxalic acid and 0.33 kg of water were added as a condensation reaction promoting catalyst.
Was added, and after mixing for 30 minutes, the temperature was raised again to 100 ° C., and the reaction was carried out for 1 hour. Furthermore, after dehydrating to 130 ° C. at normal pressure, the pressure was reduced to 1.3 KPa, and the unreacted phenol was removed until the reaction solution temperature reached 180 ° C., and taken out in a cooling vat to obtain 20.0 kg of a novolak-type phenol resin. . Table 1 shows the properties of the obtained resin.

<< Comparative Example 4 >> Metacresol 22 kg and 4
A novolak-type cresol resin 20.0 kg was obtained in the same manner as in Comparative Example 1 except that 1% K of 0% formalin and 0.22 kg of oxalic acid were used. Table 1 shows the obtained resin properties.

Comparative Example 5 A reaction was carried out in the same manner as in Comparative Example 1 except that the amount of formalin was 15.6 kg and the reaction time at 100 ° C. after the addition was 5 hours. It has become.

Comparative Example 6 After completion of the addition of formalin at 180 to 200 ° C., it was confirmed that there was no self-heating, and
A solid novolak-type phenolic resin 18.0 was obtained in the same manner as in Example 1 except that the dehydration step was started after cooling to 50 ° C.
Kg was obtained.

Table 1 shows the obtained resin characteristics.

[Table 1]

The measuring method is the same for the examples and comparative examples as follows. The weight average molecular weight was measured by a gel permission chromatography (GPC) method using an ultraviolet absorption spectrum detector using polystyrene as a standard substance. The monomer content was measured by a capillary gas chromatography method.

The ortho-ortho bond ratio was calculated by substituting the methylene group bond amount determined by ¹³ C-NMR spectrum method for the novolak type phenol resin into the following equation. In the case of a novolak-type cresol resin, the amount of methylene group bond determined by Fourier transform infrared spectroscopy was similarly substituted into the following equation and calculated. Ortho-ortho bond ratio = [(oo bond) / {(oo bond)
+ (Op-bond) + (pp-bond)}] × 100 oo-bond: number of ortho-ortho-bond methylene groups op-bond: number of ortho-para-bond methylene groups pp Bond: Number of methylene groups in para-para bond

The extracted water electric conductivity is an item for grasping the amount of ionic impurities in the resin, and the smaller the numerical value, the smaller the ionic impurities. This time, 6 g of solid resin and 40 ml of pure water were placed in a pressure cooker container, sealed, heat-treated in a thermostat at 125 ° C for 20 hours, and the extracted water was subjected to an electric conductivity meter (Toa Denpa Kogyo Co., Ltd.
-2A). The solvent solubility was determined by adding 10 g of the target resin to 100 ml of acetone and tetrahydrofuran, and mixing the mixture at room temperature for 24 hours to determine the insoluble content.

As is clear from the results of these Examples and Comparative Examples, the novolak-type phenolic resin produced by the method of the present invention has a very high molecular weight, has a solvent solubility, and has a high degree of solvent solubility. It can be seen that this is a high ortho-novolac having many ortho-ortho-position methylene bonds and extremely few ionic impurities.

[0049]

According to the method of the present invention, a solvent-soluble novolak type high molecular weight resin of phenols, particularly a novolak type high molecular weight resin of trifunctional phenols, which has not been obtained before, can be obtained. A high ortho-ortho-bonded high ortho-novolac, which has a small amount of ionic impurities that could not be simultaneously realized at the same time, has sufficient safety because of easy control of the reaction pressure during a high-temperature reaction, and has a high yield in a very short time. can get. Since the cured product is excellent in heat resistance, electrical insulation and moisture resistance, it can be applied to a wide range of applications including electric and electronic fields, and is suitable as an industrial method for producing a novolak phenolic resin.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an equipment flow used in the present invention.

FIG. 2 is a perspective view of blades of a static mixer having twisted blades inside a pipe.

FIG. 3 is a perspective view of blades of a static mixer having folded blades inside a pipe.

FIG. 4 is a molecular weight distribution chart of the resin obtained in Example 1 by GPC.

FIG. 5 is a molecular weight distribution chart of the resin obtained in Example 2 by GPC.

FIG. 6 is a GPC molecular weight distribution chart of the resin obtained in Example 3.

FIG. 7 is a GPC molecular weight distribution chart of the resin obtained in Example 4.

FIG. 8 is a GPC molecular weight distribution chart of the resin obtained in Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine-type stirring blade 2 High-pressure reactor 3 Nitrogen gas filling line 4 High-pressure metering pump of aldehydes 5 Injection nozzle of aldehydes 6 Reactor lower take-off valve 7 Double tube stationary type mixer 8 Multi-sensitive heat exchange type mixer 9 Double Tube type static mixer 10 Pressure regulating valve 11 Flash container 12 Heat exchanger

Claims (13)

[Claims] When a phenol and an aldehyde are reacted without using a catalyst, a trifunctional phenol is charged into a pressure-resistant reactor, and is pressurized with an inert gas at a pressure of 0.5 MPa or more. Aldehydes are successively added to phenols heated to a temperature of 160 ° C. to 200 ° C., and an addition condensation reaction is carried out at a reaction temperature of 160 ° C. to 200 ° C.
Dehydration and demonomerization are performed while maintaining the temperature at ℃ ~ 250 ℃,
A method for producing a novolak-type phenol resin, which comprises causing a polymerization reaction. 2. The method according to claim 1, wherein the phenol is a trifunctional phenol. 3. The weight average molecular weight when using polystyrene as a standard substance is 50,000 or more.
A method for producing the novolak-type phenol resin described in the above. 4. When a phenol and an aldehyde are reacted without using a catalyst, a trifunctional phenol is charged into a pressure-resistant reactor, and is pressurized with an inert gas at 0.5 MPa or more, and is heated at 160 ° C. or more in advance. Aldehydes are successively added to phenols heated to a temperature of 160 ° C. to 200 ° C., and an addition condensation reaction is carried out at a reaction temperature of 160 ° C. to 200 ° C.
Dehydration and demonomerization are performed while maintaining the temperature at ℃ ~ 250 ℃,
A novolak-type phenolic resin characterized in that the obtained resin is dissolved in a solvent, and the resin is precipitated and taken out while dropping pure water. The weight average molecular weight is at least 100,000 or more when polystyrene is used as a standard substance. Production method. 5. The method according to claim 4, wherein the phenol is a trifunctional phenol. 6. The method for producing a novolak-type phenol resin according to claim 4, wherein the weight average molecular weight based on polystyrene as a standard substance is 100,000 or more. 7. The method according to claim 1, wherein the molar ratio (F / P) of the phenols to the aldehydes is in the range of 0.50 to 0.85.
Or the method for producing a novolak-type phenol resin according to 4. 8. Formic acid as aldehydes at 200 PPM
5. The method according to claim 1, wherein formalin removed to the following level is used.
A method for producing the novolak-type phenol resin described in the above. 9. The method for producing a novolak-type phenolic resin according to claim 1, wherein paraformaldehyde having a purity of 80% or more is used as the aldehyde, which is dissolved or suspended in phenol. 10. The method for producing a novolak-type phenolic resin according to claim 1, wherein the aldehydes are added from the lower part of the reactor. 11. The method for producing a novolak-type phenol resin according to claim 1, wherein a reactor having a two-stage turbine-type stirring blade having the same diameter is used as the reactor. 12. The method for producing a novolak-type phenolic resin according to claim 1, wherein a static mixer is used in a reaction step after completion of the addition of the aldehyde. 13. A ketone, wherein the solvent for dissolution and separation is water and a soluble ketone;
One or a mixture of two or more of alcohols, tetrahydrofuran, and N, N-dimethylformamide, wherein 100 parts by weight of novolak-type phenol resin is used.
The method for producing a novolak-type phenol resin according to claim 4, wherein the solvent is dissolved in an amount of 1 to 1000 parts by weight, and pure water is added in an amount of 1/10 to equivalent amount of the solvent and separated.