JP2006273899A - Phenol resin and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for obtaining a phenol resin having a high ortho-form ratio and the phenol resin obtained from the method. <P>SOLUTION: This method for producing the phenol resin by reacting phenols with aldehydes is characterized with that the water content in the reaction system of the reaction is ≤10 wt.% based on the total of the reaction system, and a micro wave is used as a heating means of the reaction. Also, the phenolic resin obtained by the method of production has preferably ≥70 mol% ortho position as the bonding positions of methylene, dimethylene ether and methylol groups relative to the hydroxy groups of the phenols. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phenol resin and a method for producing the same.

  As the phenol resin, the phenolic hydroxyl group derived from phenols is a random type phenol resin in which the bonding position of the methylene group etc. is the same ratio between the ortho position and the para position, and the high ortho type with many bonds at the ortho position. Phenolic resins are known.

Random type phenolic resins usually use phenols and aldehydes as a catalyst with known organic acids and / or inorganic acids such as oxalic acid, p-toluenesulfonic acid, hydrochloric acid, sulfuric acid at normal temperature and reflux temperature. It can be obtained by a method in which an addition condensation reaction is performed for several hours, and then dehydration and unreacted monomers are removed.
On the other hand, a high-ortho type phenolic resin requires phenol and aldehyde after an addition condensation reaction under weak acidity using a divalent metal salt catalyst such as zinc acetate, lead acetate or zinc naphthenate. Accordingly, it is obtained by a step of removing the unreacted monomers after adding the acid catalyst and proceeding the condensation reaction while dehydrating (see, for example, Patent Documents 1 to 3).

  As another method, a method for producing a high-ortho-type phenol resin by setting the reaction temperature to 100 ° C. or higher under a weakly acidic catalyst (see, for example, Patent Document 4), in the presence of a basic catalyst, 100 A method of producing a high-ortho-type phenolic resin by using a reaction at a temperature of at least 100 ° C. without using a divalent metal salt catalyst (see, for example, Patent Document 5), or a divalent metal salt at a temperature of at least 110 ° C. A method for producing a high-ortho type phenolic resin without using a catalyst (for example, see Patent Document 6) is known.

In order to obtain a high-ortho type phenol resin, it is generally known that it is more advantageous to react at a high temperature, but as a method for generating a high temperature state, a method of irradiating a substance with microwaves is known.
When microwaves are used as a heating source, a phenomenon called local superheating, in which an ultra-high temperature spot that locally exceeds the boiling point of the substance is known, is usually heated sequentially from the outside In contrast, it is an inherent phenomenon that occurs because microwaves penetrate deep into the material and are heated directly from within.

  As a method for synthesizing a phenol resin by microwave irradiation, a method of adding a catalyst to a mixture of phenol and an aqueous formaldehyde solution and irradiating the mixture with microwaves (for example, see Patent Document 7) is known. In this method, since a large amount of moisture is present in the reaction system, the microwaves do not penetrate deeper, the effect of local superheating is not sufficient, and only a random type phenol resin can be obtained.

JP 55-090523 A JP 59-080418 A JP-A-62-230815 JP-A-55-155013 JP-A-57-051714 Japanese Patent Laid-Open No. 04-203212 JP 55-090523 A

  The present invention provides a method for obtaining a phenol resin having a high ortho-ratio and a phenol resin obtained by this method.

Such an object is achieved by the following present inventions (1) to (3).
(1) A method for producing a phenol resin in which phenols and aldehydes are reacted, wherein the amount of water in the reaction system during the reaction is 10% by weight or less with respect to the whole reaction system, and during the reaction A method for producing a phenol resin, characterized in that microwaves are used as heating means.
(2) A phenol resin obtained by the production method according to (1) above.
(3) The phenol resin is described in (2) above, in which 70 mol% or more of the bonding positions of methylene group, dimethylene ether group, and methylol group with respect to the phenolic hydroxyl group derived from phenol is an ortho site. Phenolic resin.

  In the present invention, when a phenol resin is produced by reacting phenols and aldehydes, the water content in the reaction system during the reaction is 10% by weight or less based on the whole reaction system, and heating means during the reaction A phenol resin production method characterized by using a microwave as the above, and the phenol resin obtained by the production method of the present invention has a high ortho-ratio.

Hereinafter, the phenol resin of the present invention and the production method thereof will be described in detail.
The method for producing a phenolic resin of the present invention is a method for producing a phenolic resin in which phenols and aldehydes are reacted, and the amount of water in the reaction system at the time of the reaction is 10% by weight or less based on the entire reaction system. And microwaves are used as the heating means during the reaction.
The phenolic resin of the present invention is obtained by the production method of the present invention.
First, a method for producing a phenol resin of the present invention (hereinafter sometimes simply referred to as “manufacturing method”) will be described.

  Although it does not specifically limit as phenols used in the manufacturing method of this invention, For example, cresol, such as phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2, 5-xylenol, 2,6-xylenol, 3,4-xylenol, xylenol such as 3,5-xylenol, ethylphenol such as o-ethylphenol, m-ethylphenol, p-ethylphenol, isopropylphenol, butylphenol, p -Butylphenol such as tert-butylphenol, p-tert-amylphenol, p-octylphenol, p-nonylphenol, alkylphenols such as p-cumylphenol, fluorophenol, chlorophenol, bromophenol, iodine Halogenated phenols such as phenol, monovalent phenol substitutes such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol and trinitrophenol, and monovalent phenols such as 1-naphthol and 2-naphthol, resorcin, Examples thereof include polyhydric phenols such as alkyl resorcin, pyrogallol, catechol, alkyl catechol, hydroquinone, alkyl hydroquinone, phloroglucin, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. Although these can be used individually or in combination of 2 or more types, generally phenol and cresol are often used.

  The aldehydes are not particularly limited, but examples include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde. Benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde and the like. These can be used alone or in combination of two or more, but usually formaldehydes such as formaldehyde and paraformaldehyde are often used.

  In the reaction of the phenols and aldehydes, an acidic catalyst or a basic catalyst can be used according to the type and properties of the target phenol resin, and these are immobilized on organic particles or inorganic particles. May be used. Furthermore, the reaction can be carried out without using these catalysts.

  Although it does not specifically limit as an acidic catalyst, For example, inorganic acids, such as hydrochloric acid, a sulfuric acid, phosphoric acid, phosphorous acid, Organic acids, such as oxalic acid, diethyl sulfuric acid, paratoluenesulfonic acid, and organic phosphonic acid, Metal salts, such as zinc acetate Etc. These can be used alone or in combination of two or more.

  The basic catalyst is not particularly limited, but examples thereof include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, and alkaline earth metal oxides and hydroxides such as calcium, magnesium and barium. Amine compounds such as primary amines such as ammonia and monoethanolamine, secondary amines such as diethanolamine, tertiary amines such as trimethylamine, triethylamine, triethanolamine and diazabicycloundecene, or sodium carbonate, Examples include alkaline substances such as hexamethylenetetramine. These can be used alone or in combination of two or more.

The reaction molar ratio (F / P) of the phenols (P) and the aldehydes (F) is not particularly limited. For example, when synthesizing a novolac type phenol resin, usually F / P = 0.1. It can be made to react as -0.95. Preferably, F / P = 0.3 to 0.9.
If the reaction molar ratio is less than the above lower limit, the yield of the resulting phenol resin tends to be low, and the molecular weight tends to be too low. On the other hand, when the reaction molar ratio exceeds the above upper limit, it is difficult to control the molecular weight, and gelation or partial gelation may be generated depending on the reaction conditions.
Moreover, when synthesizing a resol type phenol resin, it can be made to react normally as F / P = 0.9-3.0. Preferably, F / P = 0.95 to 2.5.
When the reaction molar ratio is less than the above lower limit value, the crosslinking point is insufficient, and a three-dimensional crosslinked structure may not be formed and may not be cured. On the other hand, when the reaction molar ratio exceeds the above upper limit, a large amount of unreacted aldehydes may remain.

Moreover, it does not specifically limit as reaction conditions at the time of performing the said reaction, but the temperature of a reaction system can be about 165-180 degreeC.
The reaction time is, for example, about 0.5 to 3 hours when a novolac type phenol resin is synthesized using an acidic catalyst, and about 1 to 10 hours when a novolac type phenol resin is synthesized without using a catalyst. When a resol type phenol resin is synthesized using a basic catalyst, it can be set to about 0.5 to 2 hours.

In the production method of the present invention, when the phenol resin is reacted, the amount of water in the reaction system is 10% by weight or less based on the entire reaction system. Thereby, when a microwave is used as a heating means during the reaction, the energy of the microwave can be efficiently transmitted to the reaction substrate to advance the reaction.
For this purpose, the water content in the reaction system is preferably 7% by weight or less, more preferably 5% by weight or less.

  The method for setting the amount of water in the reaction system to be equal to or lower than the above upper limit is not particularly limited. First, as a method for setting the amount of water at the start of the reaction to be equal to or lower than the upper limit, for example, aldehydes such as paraformaldehyde In addition to the method using a low content, an aqueous solution such as a formaldehyde aqueous solution can be used for dehydration treatment under normal pressure or reduced pressure before the reaction. In addition, the method of setting the amount of water in the reaction system during the reaction to the upper limit or less is not particularly limited. However, when water is produced by the reaction, the reaction is performed while removing the water under normal pressure or reduced pressure (dehydration reaction). ).

  In the production method of the present invention, a reaction solvent can be used for the reaction between phenols and aldehydes, but a polar solvent having a property of absorbing microwaves reduces the synthesis reaction efficiency of the phenol resin. Therefore, it is preferable not to use as much as possible.

In the production method of the present invention, microwaves are used as a heating source for the reaction between phenols and aldehydes. Thereby, it is possible to synthesize a phenol resin having a high ortho ratio.
When microwaves are used as a heating source, the reason why such a phenolic resin can be synthesized is not clear, but because microwaves penetrate deep into the material and are heated directly from the inside by irradiation with microwaves. In addition, it is thought that this is due to a phenomenon called local superheating in which an ultra-high temperature spot that locally exceeds the boiling point of the substance occurs.

In the production method of the present invention, the frequency of the microwave that can be used as a heat source is not particularly limited. Currently, according to the Radio Law, microwaves in the frequency bands of 433.05 to 434.79 MHz, 890 to 940 MHz, 2400 to 2500 MHz, 5725 to 5875 MHz, and 24.000 to 24.250 GHz can be used in Japan. When applied to the manufacturing method of the present invention, microwaves in frequency bands other than those described above can also be used.
Further, the output of the microwave is not particularly limited, and can be appropriately selected according to the scale of the manufacturing apparatus, the property of the phenol resin to be synthesized, and the like.

  In the production method of the present invention, microwave irradiation can be applied to part or all of the phenol resin synthesis step. Alternatively, microwave irradiation and a normal heating method can be used in combination. Such a case is also included in the present invention.

  In the production method of the present invention, the form of performing the microwave irradiation is not particularly limited. For example, a method of using a material that hardly absorbs microwaves in the reaction vessel and irradiating the microwaves from the outside of the reaction vessel Alternatively, a method of irradiating microwaves in a reaction system by installing a microwave oscillating device inside the reaction vessel may be used.

Next, the phenol resin of the present invention will be described.
The phenol resin of the present invention is obtained by the production method of the present invention.

In the phenol resin of the present invention, it is preferable that 70 mol% or more of the bonding positions of the methylene group, dimethylene ether group, and methylol group with respect to the phenolic hydroxyl group of the phenol is an ortho site. More preferably, it is 70-99 mol%.
The production method of the present invention can efficiently synthesize a phenol resin having a high ortho-rification rate as described above.
The methylene group, dimethylene ether group, and methylol group are all group names when formaldehyde is used as the aldehyde, but when aldehydes other than formaldehyde are used, the substituted methylene group, It becomes a substituted dimethylene ether group and a substituted methylol group. Such a case is also included in the present invention.

As a method for synthesizing such a phenol resin, for example, phenol and paraformaldehyde are charged into a reactor, and the water content in the reaction system is 0.1 to 10 wt. It can synthesize | combine by making it maintain at% and making it react at 165-170 degreeC for 0.5 to 10 hours.
In the phenol resin of the present invention, the method for increasing the ortho ratio is not particularly limited. For example, as reaction conditions, the water content in the reaction system is 0.1 to 5% by weight, and the reaction temperature is 170 to 180 ° C. And a method of using a divalent metal salt such as zinc acetate as a catalyst, a method of reacting in a system not using a catalyst, a method of combining these, and the like.

  The form of the phenol resin of the present invention is not particularly limited, and it can be obtained in either liquid or solid form.

In the phenolic resin of the present invention, the ortho ratio can be measured from an IR spectrum.
Specifically, for example, when measuring a phenol resin obtained by a reaction between phenol and formaldehyde, an ortho-methylene bond (730) is obtained from the obtained IR spectrum using a Fourier transform infrared spectrophotometer. ~770cm ^-1, less D760), from the absorbance of para methylene bond (800~840cm ^-1, less D820), by correcting the absorbance of D820, it can be calculated by the following equation.
Orthoformation rate (%) = 100 × [D760 / (D760 + D820 × 1.44)]

As described above, in the present invention, when a phenol resin is produced by reacting phenols and aldehydes, the amount of water in the reaction system during the reaction is 10% by weight or less based on the entire reaction system. There is a method for producing a phenol resin, characterized in that microwaves are used as a heating means during the reaction.
And the phenol resin of this invention obtained by this manufacturing method is a thing with a high ortho-ratio, and can be applied suitably for the use as which such a property is requested | required.

  Hereinafter, the present invention will be described by way of examples.

[Example 1]
A flask equipped with a stirrer was charged with 1000 parts by weight of phenol, 243 parts by weight of paraformaldehyde (243 parts by weight) (F / P ratio = 0.7), and 10 parts by weight of oxalic acid. The water content in the reaction system before starting the reaction was 1.5% by weight.
The flask was equipped with a multi-mode type microwave irradiation device, placed in a grounded shield case, irradiated with 2450 MHz microwave at an output of 600 W, while removing water generated by the reaction at normal pressure, The water content was adjusted to 2.0 to 5.0% by weight at 165 ° C. for 1 hour to obtain 881 parts by weight of a novolak type phenol resin.
The obtained novolak-type phenol resin had an ortho-conversion rate of 72.2 mol%.

[Example 2]
A flask equipped with a stirrer was charged with 1000 parts by weight of phenol and 243 parts by weight of paraformaldehyde (243 parts by weight) (F / P ratio = 0.7). The water content in the reaction system before starting the reaction was 1.6% by weight.
The flask was installed in the apparatus, and a microwave of 2450 MHz was irradiated at an output of 600 W to remove water generated by the reaction at normal pressure, while setting the water content in the reaction system to 2.0 to 5.0% by weight. The mixture was reacted at 170 ° C. for 6 hours to obtain 542 parts by weight of a novolac type phenol resin.
The obtained novolac type phenol resin had an ortho-conversion rate of 80.8 mol%.

[Example 3]
A flask equipped with a stirrer was charged with 1000 parts by weight of phenol and 243 parts by weight of paraformaldehyde (243 parts by weight) (F / P ratio = 0.7). The water content in the reaction system before starting the reaction was 1.6% by weight.
Next, the reaction system was dehydrated under reduced pressure using a decompression device, and the water content in the reaction system was adjusted to 0.2 to 0.5 wt%.
The flask was installed in the apparatus, and a microwave of 2450 MHz was irradiated at an output of 600 W to remove water generated by the reaction at normal pressure, while setting the water content in the reaction system to 0.2 to 0.5% by weight. The mixture was reacted at 175 ° C. for 6 hours to obtain 549 parts by weight of a novolac type phenol resin.
The obtained novolak-type phenol resin had an orthoconversion ratio of 85.9 mol%.

[Example 4]
A flask equipped with a stirrer was charged with 1000 parts by weight of phenol, 485 parts by weight of 92% by weight paraformaldehyde (F / P ratio = 1.4), and 8 parts by weight of zinc acetate. The water content in the reaction system before starting the reaction was 1.6% by weight.
The flask was installed in the apparatus, and a microwave of 2450 MHz was irradiated at an output of 600 W to remove water generated by the reaction at normal pressure, while setting the water content in the reaction system to 2.0 to 3.0% by weight. The mixture was reacted at 170 ° C. for 30 minutes to obtain 887 parts by weight of dimethylene ether type resole resin.
The obtained dimethylene ether type resole resin had an ortho-conversion rate of 81.0 mol%.

[Comparative Example 1]
A flask equipped with a stirrer and a condenser was charged with 1000 parts by weight of phenol, 243 parts by weight of paraformaldehyde (243 parts by weight) (F / P ratio = 0.7), and 10 parts by weight of oxalic acid.
This was heated in an oil bath and reacted at 165 ° C. for 1 hour while removing water generated by the reaction at normal pressure to obtain 894 parts by weight of a novolak type phenol resin.
The obtained novolac type phenol resin had an orthoconversion ratio of 52.4 mol%.

[Comparative Example 2]
A flask equipped with a stirrer and a condenser was charged with 1000 parts by weight of phenol and 243 parts by weight of paraformaldehyde of 92% by weight (F / P ratio = 0.7).
This was heated in an oil bath and reacted at 170 ° C. for 6 hours while removing water generated by the reaction at normal pressure to obtain 532 parts by weight of a novolak type phenol resin.
The obtained novolak-type phenol resin had an ortho-conversion rate of 65.5 mol%.

[Comparative Example 3]
A flask equipped with a stirrer and a condenser was charged with 1000 parts by weight of phenol, 485 parts by weight of paraformaldehyde (485% by weight) (F / P ratio = 1.4), and 8 parts by weight of zinc acetate.
This was heated in an oil bath and reacted at 170 ° C. for 30 minutes while removing water generated by the reaction at normal pressure to obtain 902 parts by weight of dimethylene ether type resole resin.
The obtained dimethylene ether type resole resin had an orthoconversion ratio of 68.1 mol%.

The orthorization rate of the novolak type phenol resin obtained in the Examples and Comparative Examples was measured by the following method.
From the IR spectra of the phenol resins obtained in the above examples and comparative examples using a Fourier transform infrared spectrophotometer (Avatar 320 manufactured by Nicolet), ortho-position methylene bonds (730 to 770 cm ⁻¹ , hereinafter referred to as D760), para The absorbance of D820 was corrected from each absorbance of the coordinate methylene bond (800 to 840 cm ⁻¹ , hereinafter referred to as D820), and calculated by the following formula.
Orthoformation rate (%) = 100 × [D760 / (D760 + D820 × 1.44)]

  Examples 1 to 4 are phenol resins obtained by the production method of the present invention in which the moisture content in the reaction system is 10% by weight or less and microwaves are used as the heating means during the reaction, and the normal heating means is applied. In comparison with Comparative Examples 1 to 3, it was possible to synthesize a novolak type phenol resin and a dimethylene ether type resol resin having a high ortho-ratio.

In the present invention, when a phenol resin is produced by reacting phenols and aldehydes, the amount of water in the reaction system at the time of the reaction is 10% by weight or less based on the whole reaction system, and heating means at the time of reaction A method for producing a phenolic resin, characterized by using microwaves.
And the phenol resin of this invention obtained by this manufacturing method is a thing with a high ortho-ratio, and can be applied suitably for the use as which such a property is requested | required.

Claims (3)

A method for producing a phenol resin in which phenols and aldehydes are reacted, wherein the water content in the reaction system during the reaction is 10% by weight or less based on the whole reaction system, and heating means during the reaction A method for producing a phenol resin, characterized in that microwaves are used. A phenol resin obtained by the production method according to claim 1. 3. The phenol resin according to claim 2, wherein 70 mol% or more of the bonding positions of the methylene group, dimethylene ether group, and methylol group with respect to the phenolic hydroxyl group derived from phenols is an ortho site.