JP2004323630A - Preparation method for phenol resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preparation method whereby a phenol resin containing a low-molecular component, such as a phenol or a binuclear compound, in a low content and having a narrow molecular weight distribution is prepared with a high yield without worsening the work environment. <P>SOLUTION: The preparation method for a phenol resin comprises reacting a phenol with an aldehyde containing at least a formaldehyde polymer in the presence of an organophosphonic acid as a catalyst. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４４】
表１にみられるように、各実施例のものは、遊離フェノールや２核体の含有率が低いと共に、分子量分布が狭く、また収率が高いものであった。
【００４５】
【発明の効果】
上記のように本発明の請求項１に係るフェノール樹脂の製造方法は、ホルムアルデヒドの重合体を少なくとも含むアルデヒド類とフェノール類とを、有機ホスホン酸を触媒として反応させるようにしたので、有機ホスホン酸を触媒として用いると共にアルデヒド類として含有水分が少ないアルデヒドの重合体を用いることによって、フェノール類のモノマーや２核体などの低分子成分が少なく、分子量分布が狭いフェノール樹脂を収率高く製造することができものであり、しかもアルデヒドの重合体は臭気が少なく作業環境を悪化させることなく製造を行なうことができるものである。
【００４６】
また請求項２の発明は、請求項１において、ホルムアルデヒド重合体を５０質量％以上含むアルデヒド類を用いるようにしたので、フェノール類のモノマーや２核体などの低分子成分が少なく、分子量分布が狭いフェノール樹脂を収率高く、しかも作業環境を悪化させることなく製造することができるものである。
【００４７】
また請求項３の発明は、請求項１又は２において、ホルムアルデヒド重合体が、ホルムアルデヒド環状重合体であるので、ホルムアルデヒド環状重合体は臭気が少なく作業環境を悪化させることなく製造を行なうことができるものである。
【００４８】
また請求項４の発明は、請求項１又は２において、ホルムアルデヒド重合体が、アセタール樹脂であるので、アセタール樹脂は臭気が少なく作業環境を悪化させることなく製造を行なうことができるものである。
【００４９】
また請求項５の発明は、請求項１乃至４のいずれかにおいて、反応系中の水の含有量が２０質量％以下になるように調整しながら、１２０℃以上の反応温度で反応させるようにしたので、フェノール類のモノマーや２核体など低分子成分の反応を優先的に行なわせることができ、フェノール類のモノマーや２核体などの低分子成分が少なく、分子量分布が狭いフェノール樹脂を収率高く、しかも作業環境を悪化させることなく製造することができるものである。[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is suitably used as a binder for a refractory or molding material for casting, a grindstone, a brake lining, a sliding member for a bearing, a sealing material for an electronic component, or as a non-halogen flame retardant. The present invention relates to a method for producing a novolak type phenol resin.
[0002]
[Prior art]
Thermoplastic novolak-type phenol resins have been conventionally used as molding materials or binders for the above-mentioned various uses, or as flame retardants.
[0003]
This novolak type phenol resin is prepared by reacting a phenol and an aldehyde with an inorganic acid such as hydrochloric acid or sulfuric acid or an organic acid such as oxalic acid, paratoluenesulfonic acid, benzenesulfonic acid or the like as a reaction catalyst. Here, the molecular weight of the phenolic resin can be adjusted by adjusting the molar ratio of the phenols to the aldehydes. However, the molecular weight distribution of the resin is wide, and the monomer (free phenols) and the binucleate (the phenols Low molecular components such as dimer) are likely to remain. Therefore, the reaction product is subjected to steam distillation, molecular distillation, or washing with a solvent to remove low molecular components such as monomers and binuclear substances.
[0004]
However, such a method of removing low molecular components such as a monomer and a binuclear substance from a reaction product has a problem that the number of manufacturing steps and energy consumption are increased, and the yield is greatly reduced. Therefore, recently, new polymerization methods for dealing with these have been proposed in Patent Documents 1 and 2.
[0005]
In the method of Patent Document 1, the reaction is carried out using an organic phosphonic acid which has been conventionally recognized as an acid catalyst but has been difficult to be put into practical use. Thus, a novolak-type phenol resin having a small amount of unreacted phenols and a narrow molecular weight distribution can be obtained in high yield. Further, the method of Patent Document 2 is a reaction system using an organic phosphonic acid as an acid catalyst in this way, by reducing the water content to 30% by mass or less, thereby further reducing unreacted phenols and narrowing the molecular weight distribution. A novolak-type phenol resin can be obtained in high yield.
[0006]
[Patent Document 1]
JP 2001-329034 A [Patent Document 2]
JP-A-2002-194041
[Problems to be solved by the invention]
By reacting phenols with formaldehyde using an organic phosphonic acid as an acid catalyst as described above, a novolak-type phenol resin having a small amount of unreacted phenols and a narrow molecular weight distribution can be produced.
[0008]
However, in the methods of Patent Documents 1 and 2, phenolic monomers can be reduced, but binuclides have not been sufficiently reduced. As the aldehyde used in the reaction, formalin, which is an aqueous solution of formaldehyde in an amount of about 35 to 50% by mass, is generally used. There is a limit in reducing or narrowing the molecular weight distribution. Further, formalin has a problem that it has a strong odor and is not preferable in a working environment.
[0009]
The present invention has been made in view of the above points, and has a low yield of phenolic resins having a low molecular weight distribution such as low molecular components such as phenolic monomers and binuclears, and without deteriorating the working environment. It is an object of the present invention to provide a method for producing a phenol resin that can be produced.
[0010]
[Means for Solving the Problems]
The method for producing a phenolic resin according to claim 1 of the present invention is characterized in that an aldehyde containing at least a formaldehyde polymer and a phenol are reacted with an organic phosphonic acid as a catalyst.
[0011]
The invention of claim 2 is characterized in that, in claim 1, aldehydes containing 50% by mass or more of a formaldehyde polymer are used.
[0012]
In a third aspect of the present invention, in the first or second aspect, the formaldehyde polymer is a formaldehyde cyclic polymer.
[0013]
A fourth aspect of the present invention is the method according to the first or second aspect, wherein the formaldehyde polymer is an acetal resin.
[0014]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the reaction is carried out at a reaction temperature of 120 ° C. or more while adjusting the content of water in the reaction system to 20% by mass or less. It is a feature.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0016]
In the present invention, phenols mean phenol and phenol derivatives. Examples of phenols include trifunctional compounds such as m-cresol, resorcinol and 3,5-xylenol, tetrafunctional compounds such as bisphenol A, bisphenol S and dihydroxydiphenylmethane, o-cresol, p-phenol and the like. Bifunctional o- or p-substituted phenols such as cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, 2,4- or 2,6-xylenol, etc. And a halogenated phenol substituted with chlorine or bromine. As the phenols, one kind may be selected and used, or a plurality of kinds may be mixed and used.
[0017]
In the present invention, formaldehydes include at least a formaldehyde polymer. Examples of the formaldehyde polymer include a formaldehyde linear polymer such as paraformaldehyde, a formaldehyde cyclic polymer such as trioxane and tetraoxane, and a formaldehyde polymer resin such as an acetal resin. These may be used alone or in combination of two or more.
[0018]
As the aldehydes other than the formaldehyde polymer, formalin, acetaldehyde, benzaldehyde, etc. in the form of an aqueous formaldehyde solution can be used, and other aldehydes in which part or most of the aldehyde is replaced with furfural or furfuryl alcohol are used. It is also possible.
[0019]
The organic phosphonic acid used as an acid catalyst in the present invention is represented by a general formula of R-PO (OH) ₂ (R contains a carbon atom and contains at least one of -COOH and -PO (OH) ₂ ). For example, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylphosphonic acid, ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, β-aminoethylphosphonic acid N, N-diacetic acid, aminomethylphosphonic acid N, N-diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid and the like can be mentioned. These may be used alone or in combination of two or more, and may also be used in combination with a conventionally used catalyst depending on the purpose such as increasing the softening point of the phenol resin. Things.
[0020]
According to the present invention, a novolak-type phenol resin is produced by reacting an aldehyde containing at least a formaldehyde polymer with a phenol using an organic phosphonic acid as a catalyst. The mixing ratio of phenols and aldehydes is preferably such that the molar ratio of phenols to aldehydes is in the range of 1: 0.1 to 1: 0.98, and 1: 0.2 to 1 : More preferably in the range of 0.95. The amount of the organic phosphonic acid is not particularly limited, but is preferably in the range of 0.1 to 500 parts by mass, more preferably 1 to 300 parts by mass, and still more preferably 100 parts by mass of phenols. Is in the range of 2 to 200 parts by mass. The aldehydes may be charged at once or may be gradually added.
[0021]
When reacting phenols and aldehydes using an organic phosphonic acid as a catalyst as described above, the organic phosphonic acid is water-soluble, but the solubility of the organic phosphonic acid in phenols is low, and the solubility further decreases as the molecular weight increases. For this reason, the reaction system is phase-separated into water in which organic phosphonic acid is dissolved, phenols, and reaction products, and low-molecular components such as phenolic monomers and binuclides are relatively easily dissolved in water. The reaction is preferentially carried out at the interface between the monomer or binuclear compound and the organic phosphonic acid, and the phenol monomer or binuclear compound preferentially reacts with the aldehyde to polymerize. In this way, a low-molecular component such as unreacted phenols and binuclear substances can be reduced, and a novolak-type phenol resin having a narrow molecular weight distribution can be prepared in high yield.
[0022]
At this time, if the content of water in the reaction system is large, the reaction product is easily dissolved or dispersed in water, so that the reaction with the aldehydes occurs uniformly in this aqueous phase, and as a result, The resulting phenolic resin has a broad molecular weight distribution, and many phenolic monomers and binuclides remain. Therefore, it is important that high-molecular-weight products other than low-molecular-weight components are not dissolved in the reaction system so as not to be involved in the reaction, and it is necessary to reduce the amount of water in the reaction system.
[0023]
Here, formalin is generally used as an aldehyde to be reacted with phenols. Formalin is an aqueous solution of about 35 to 50% by mass of formaldehyde and contains about 65 to 50% by mass of water. Therefore, when using formalin as an aldehyde, it is difficult to reduce the amount of water in the reaction system. On the other hand, since the amount of water contained in the formaldehyde polymer is extremely small, it is easy to adjust the amount of water in the reaction system to be small. For this reason, in the present invention, a formaldehyde polymer is used as at least a part of the aldehydes.
[0024]
For example, paraformaldehyde is solid and has a water content of at most about 3 to 10% by mass, and has a slight odor, but is much less than formalin. Further, cyclic formaldehyde polymers such as trioxane and tetraoxane are solid and have a water content of 1% by mass or less, and polyacetal resins obtained by polymerization of formaldehyde are solid and have a very small water content of 0.5% by mass or less. All are almost odorless and have no odor. Paraformaldehyde is decomposed into formaldehyde by heating, and formaldehyde cyclic polymers such as trioxane and tetraoxane, and polyacetal resins are easily mixed with highly reactive phenols and the like, and easily added by adding a catalyst such as heat or acid. It is broken down into formaldehyde by ringing or breaking of the molecular chain, and this formaldehyde contributes to the reaction with phenols.
[0025]
As described above, by using a formaldehyde polymer as at least a part of the aldehydes, the amount of water in the reaction system is reduced, low-molecular components such as phenolic monomers and binuclear compounds are reduced, and a novolak having a narrow molecular weight distribution is obtained. In order to prepare the type phenol resin in a high yield, it is preferable that 50% by mass or more of the aldehydes is a formaldehyde polymer. The higher the ratio of the formaldehyde polymer, the better, and the formaldehyde polymer may be used as all of the aldehydes.
[0026]
The water content in the reaction system is preferably 20% by mass or less, and when the water content in the reaction system exceeds 20% by mass, low-molecular components such as phenolic monomers and binuclear substances are reduced. In addition, it becomes difficult to prepare a novolak-type phenol resin having a narrow molecular weight distribution in high yield. The lower limit of the amount of water in the reaction system is not particularly limited, but practically, it is preferable that about 2% by mass or more of water is present in the reaction system.
[0027]
The above reaction is preferably carried out at a reaction temperature of 120 ° C. or higher. By setting the reaction temperature to a high temperature of 120 ° C. or higher, low-molecular components such as unreacted phenols and binuclear compounds are easily dissolved in water, and the reaction of these low-molecular components proceeds easily. Thus, it is easy to prepare a high-yield novolak-type phenol resin having a narrow molecular weight distribution by reducing low-molecular components such as phenol monomers and binuclear substances. Although the upper limit of the reaction temperature is not particularly limited, it is practically preferable that the reaction temperature does not exceed about 180 ° C.
[0028]
As described above, in order to keep the water content in the reaction system to a certain amount or less, for example, 20% by mass or less, while removing condensed water generated when phenols and aldehydes react, The reaction is allowed to proceed. Here, the content of water in the reaction system refers to the amount of water contained in the entire raw materials such as phenols, aldehydes, and organic phosphonic acids in the stage before the reaction, and during the reaction. In other words, it refers to the amount of water contained with respect to the total amount including the reaction products. In particular, when condensation water is generated in the middle of the reaction and the amount of water increases, the boiling temperature of the reaction system may be lowered to 120 ° C. or less, so that dehydration is performed so that the reaction temperature does not become 120 ° C. or less. It is necessary to continue the reaction while performing the reaction. If this operation is not performed, the reaction of low molecular components such as phenolic monomers and binuclear compounds will not be performed preferentially, and a novolak type phenol resin having a large amount of low molecular components remaining and a broad molecular weight distribution will be obtained. Will be done.
[0029]
After the completion of the above reaction, water washing is performed in accordance with a conventional method to remove the catalyst and the remaining unreacted monomer, and further, the water is removed by raising the temperature or reducing the pressure, thereby obtaining a thermoplastic novolak. A phenolic resin can be obtained.
[0030]
The novolak-type phenolic resin thus prepared is thermoplastic and does not cure when heated, so that when used as a molding material or binder, hexamethylenetetramine is generally added and mixed as a curing agent. At this time, since the phenolic resin obtained in the present invention has a low content of low molecular components such as phenolic monomers and binuclear substances, hexamethylenetetramine is not consumed by these low molecular weight components, Can be reduced. Hexamethylenetetramine is thermally decomposed into formaldehyde and ammonia, and this formaldehyde reacts with the phenolic resin to cure the phenolic resin, but part of it is released into the atmosphere, and part of the ammonia is a cured product of the phenolic resin. Although it is taken in, most of it is released into the atmosphere as ammonia gas. Therefore, the fact that the blending amount of hexamethylenetetramine can be reduced means that the working environment can be prevented from deteriorating due to the odor due to the emission of formaldehyde and ammonia.
[0031]
In addition, a resol-type phenol resin can be used as a curing agent for the novolak-type phenol resin. However, in this case, the amount of the resol-type phenol resin used can be similarly reduced. When the amount of the resol-type phenol resin used is reduced in this manner, condensation water generated during curing can be reduced, and voids or peeling may occur due to moisture contained in the cured product. Can be suppressed.
[0032]
Further, the novolak type phenol resin can also be used as a flame retardant such as a polyester resin, a polyamide resin, and a polybutylene terephthalate resin. Halogen-containing organic substances containing halogen are generally used as flame retardants, but in recent years, non-halogen flame retardants have been demanded due to environmental pollution problems and the like. Considered and starting to be used. When heated, the novolak-type phenol resin undergoes thermal decomposition by the heat, generates water due to the phenolic hydroxyl group, and is cooled by endothermic and heat of vaporization accompanying the thermal decomposition. It exhibits flame retardancy. In addition, since the novolak-type phenol resin has a high carbonization yield, the fact that it is easy to thermally decompose and form a carbonized layer also contributes to the improvement of flame retardancy. Here, if the novolak-type phenol resin contains a large amount of low molecular components such as phenolic monomers and binuclear compounds, these low molecular components are vaporized when exposed to heat or flame, causing ignition, Although it is not preferable because the self-digestion is difficult to be expressed, the phenolic resin obtained in the present invention has a low content of low molecular components, so that such a phenomenon is suppressed, and the performance as a flame retardant is exhibited to a high degree. That can be done.
[0033]
【Example】
Next, the present invention will be described specifically with reference to examples.
[0034]
(Example 1)
A reaction vessel was charged with 940 g of phenol and 376 g of a 60% by mass aqueous solution of 1-hydroxyethylidene-1,1-diphosphonic acid (“Feriox-115” manufactured by Lion Corporation) as an acidic catalyst. Next, the internal temperature was raised to 120 ° C., and 261 g of paraformaldehyde having a formaldehyde concentration of 92% by mass was gradually introduced as aldehydes over about 60 minutes while removing the liquid so as not to be lower than 120 ° C. . The water content contained in the entire raw material not containing condensed water was 10.9% by mass. Thereafter, the reaction was performed at an internal temperature of 125 to 130 ° C. for 60 minutes. At this time, about 1 g was sampled and the molecular weight was measured (this molecular weight measurement is referred to as “molecular weight measurement before washing”). Here, the molecular weight was measured using a high-performance liquid chromatograph “HLC-802A” manufactured by Tosoh Corporation using THF as a mobile phase. The columns used were G1000H × 1, G2000H × 2, and G3000H × 1 using TSK Gel for HPLC.
[0035]
Next, after adding 500 g of warm water of about 60 ° C. and stirring well, a phase in which water and the catalyst were mixed was removed. After performing this washing operation three times, the liquid was removed to an internal temperature of 180 ° C. at a reduced pressure of 0.02 MPa.
[0036]
Thus, 1028 g of a novolak-type phenol resin was obtained. The molecular weight of the obtained novolak-type phenol resin was measured using a high performance liquid chromatograph in the same manner as described above (this molecular weight measurement is referred to as “molecular weight measurement after washing”).
[0037]
(Example 2)
As aldehydes, instead of paraformaldehyde, 120 g of trioxane was gradually added in about 30 minutes, and 300 g of formalin having a concentration of 37% by mass was gradually added in about 60 minutes. The water content at the time of this preparation was 19.0% by mass. Otherwise, in the same manner as in Example 1, 1015 g of a novolak-type phenol resin was obtained. Further, the measurement of the molecular weight before washing and the measurement of the molecular weight after washing were performed in the same manner as in Example 1.
[0038]
(Example 3)
As aldehydes, 240 g of trioxane was gradually added in about 60 minutes instead of paraformaldehyde. The water content during this preparation was 9.7% by mass. Otherwise, in the same manner as in Example 1, 1035 g of a novolak-type phenol resin was obtained. Further, the measurement of the molecular weight before washing and the measurement of the molecular weight after washing were performed in the same manner as in Example 1.
[0039]
(Example 4)
As the aldehydes, 240 g of an acetal resin ("Duracon" manufactured by Polyplastics Co., Ltd.) was gradually added in about 60 minutes instead of paraformaldehyde. The water content during this preparation was 9.7% by mass. Otherwise, in the same manner as in Example 1, 1033 g of a novolak-type phenol resin was obtained. Further, the measurement of the molecular weight before washing and the measurement of the molecular weight after washing were performed in the same manner as in Example 1.
[0040]
(Comparative Example 1)
A reaction vessel was charged with 940 g of phenol, 649 g of formalin having a concentration of 37% by mass, and 4.7 g of oxalic acid as an acidic catalyst. The water content at the time of this preparation was 25.7% by mass. Next, the mixture was refluxed for about 60 minutes and allowed to react for 120 minutes. The mixture was dehydrated at normal pressure to an internal temperature of 160 ° C., and then drained to 180 ° C. at 0.013 MPa. Thus, 968 g of a novolak type phenol resin was obtained. The molecular weight of the obtained novolak-type phenol resin was measured using a high performance liquid chromatograph in the same manner as in Example 1.
[0041]
(Comparative Example 2)
As the acidic catalyst, 376 g of the same phosphonic acid as in Example 1 was used instead of oxalic acid. The water content at the time of this preparation was 28.4% by mass. Otherwise, in the same manner as in Comparative Example 1, 978 g of a novolak-type phenol resin was obtained. The molecular weight of the obtained novolak-type phenol resin was measured using a high performance liquid chromatograph in the same manner as in Example 1.
[0042]
From the molecular weight measurements performed in Examples 1 to 4 and Comparative Examples 1 and 2, the content of free phenol, phenol binuclear, trinuclear or higher was calculated, and a calibration curve using polystyrene was applied. The average molecular weight was determined from UV, and the molecular weight distribution was further calculated. Further, the softening points of the novolak-type phenol resins obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were measured based on JIS K 6910, and the yield of the novolak-type phenol resin (based on phenol) was calculated. 1 is shown.
[0043]
[Table 1]

[0044]
As shown in Table 1, each of the examples had a low content of free phenol and binuclear compounds, a narrow molecular weight distribution, and a high yield.
[0045]
【The invention's effect】
As described above, in the method for producing a phenolic resin according to claim 1 of the present invention, an aldehyde containing at least a formaldehyde polymer is reacted with a phenol using an organic phosphonic acid as a catalyst. A low-molecular-weight component such as a phenolic monomer or binuclear compound with a low molecular weight distribution and a narrow molecular weight distribution can be produced at a high yield by using an aldehyde polymer with a low water content as an aldehyde as a catalyst. The aldehyde polymer has a low odor and can be produced without deteriorating the working environment.
[0046]
The invention of claim 2 uses an aldehyde containing at least 50% by mass of a formaldehyde polymer in claim 1, so that low molecular components such as phenolic monomers and binuclear substances are small and the molecular weight distribution is low. A narrow phenol resin can be produced at a high yield without deteriorating the working environment.
[0047]
According to a third aspect of the present invention, in the first or second aspect, since the formaldehyde polymer is a formaldehyde cyclic polymer, the formaldehyde cyclic polymer has a low odor and can be produced without deteriorating the working environment. It is.
[0048]
According to a fourth aspect of the present invention, in the first or second aspect, since the formaldehyde polymer is an acetal resin, the acetal resin has a low odor and can be produced without deteriorating the working environment.
[0049]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the reaction is performed at a reaction temperature of 120 ° C. or more while adjusting the content of water in the reaction system to 20% by mass or less. Therefore, it is possible to preferentially react low molecular components such as phenolic monomers and binuclears, and to use phenolic resins with a low molecular weight distribution and low phenolic monomers and binuclears. It can be produced at a high yield without deteriorating the working environment.

Claims (5)

A method for producing a phenol resin, comprising reacting an aldehyde containing at least a formaldehyde polymer with a phenol using an organic phosphonic acid as a catalyst. The method for producing a phenolic resin according to claim 1, wherein an aldehyde containing a formaldehyde polymer in an amount of 50% by mass or more is used. The method for producing a phenolic resin according to claim 1 or 2, wherein the formaldehyde polymer is a formaldehyde cyclic polymer. The method for producing a phenolic resin according to claim 1 or 2, wherein the formaldehyde polymer is an acetal resin. The phenolic resin production according to any one of claims 1 to 4, wherein the reaction is carried out at a reaction temperature of 120 ° C or higher while adjusting the content of water in the reaction system to 20% by mass or less. Method.