JPH0681775B2 - Method for producing polyhydroxy compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing a polyhydroxy compound, more specifically, a novel and useful method for producing a polyhydroxy compound having a narrow molecular weight distribution range and a low melt viscosity. Regarding

Conventional technology Conventionally, as curing agents for epoxy resins, amines,
Acid anhydrides, phenol novolac resins, etc. have been used, but in recent years, even in applications such as laminates, encapsulants, and powder coatings, due to the demand for higher performance and lower prices of products, phenol novolac resins have been used. The resin has been reviewed, and the resin is particularly preferably used for electrical / electronic materials. Thus, the phenol novolak resin is generally obtained by subjecting phenols and formaldehyde to a condensation reaction in the presence of an acid catalyst,
Phenol nuclei mainly linked by methylene bonds 2
It is considered to be a linear molecule with a wide molecular weight distribution consisting of ~ 20 molecules. As the above-mentioned raw material phenols, usually, carboxylic acid having one phenolic hydroxyl group, orthocresol, etc. are used, and the resulting resin contains unreacted phenol monomer and a low cloth molecular weight component consisting of a binuclear body. . From these things, when this resin is used as a curing agent, it is difficult to provide a cured product having a high cross-linking density, and thus the obtained cured product has heat resistance, chemical resistance,
It has a drawback that it is not satisfactory in terms of mechanical properties. On the other hand, since the resin contains a large amount of components having a relatively high molecular weight of 5 or more nuclei, the flowability at the time of molding and processing in the above applications is not sufficient, and as a result, workability is poor.

A co-condensed novolak resin obtained by simultaneously charging two or more phenols and formaldehyde and subjecting them to a condensation reaction is also known. This also has a wide molecular weight distribution range as seen in the above-mentioned general phenol novolak resin. Even when the content of the monomer is adjusted to 1% by weight or less by an operation such as distillation, it contains a large number of molecules of a dinuclear body which is a low molecular weight component and a pentanuclear body which is a high molecular weight component. That is, since the acidity: Mw / Mn (Mw indicates a weight average molecular weight value and Mn indicates a number average molecular weight value) is relatively high, the workability is inferior as in the above case.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In view of the above-mentioned prior art, the present invention mainly relates to a new polyfunctional phenol resin having excellent properties as a curing agent for an epoxy resin, more particularly a trinuclear body and a tetranuclear body. An object of the present invention is to provide a method for producing a polyfunctional phenol resin having a narrow molecular weight distribution as a component.

Means to solve the problem (In the formula, R ¹ represents an alkyl group having 1 to 10 carbon atoms), obtained by reacting 1 mol of an ortho-substituted phenol with 1.5 to 2.5 mol of formaldehyde or a formaldehyde source material under alkaline conditions. Resol (A), difunctional or higher functional phenols (B),
Condensation under acidic conditions at a ratio of 1.1 to 20 times the molar amount of the ortho-substituted phenols used in the production of (A), further dehydration and demonomerization to give a trinuclear body and a tetranuclear body. Total content is 45% by weight or more and polydispersity is 1.20
This is achieved by a method for producing a polyhydroxy compound, characterized in that the following polyhydroxy compound is obtained.

Here, the specific resol (A) has the general formula (In the formula, R ¹ is the same as above) and a dimethylol derivative of an ortho-substituted phenol and / or a general formula (In the formula, R ¹ is the same as above.) A dimethylol derivative of dihydroxydiphenylmethane represented by the general formula (2)
(Condensation product of the dimethylol derivative of 1) as a main component.

As a result of earnest research, the present inventor, as described above, uses a specific resol (A) as a starting material, and uses this in the presence of an acid catalyst to convert a bifunctional or higher functional phenol (B) into a methylol group in the resol. On the other hand, when the reaction was carried out in an excess amount, it was found that the desired compound can be obtained by subsequent dehydration and demomerization by ordinary distillation operation, and the present invention was completed here.

The polyhydroxy compound obtained by the present invention is a resin having a narrow molecular weight distribution containing trinuclear and tetranuclear as main components, and has a low melt viscosity as compared with a conventional novolak resin having the same softening point. There is. Therefore, it can exhibit extremely excellent characteristics as a curing agent for epoxy resin. For example, when used as a molding material, it can provide a material with good flowability, and a cured product obtained by curing the material has mechanical properties. In addition to being excellent in chemical resistance, it is particularly excellent in heat resistance.

In the present invention, ortho-substituted phenols are used as the starting component of the specific resol (A), and the ortho-substituted phenols include ortho-cresol,
Orthoethylphenol, orthopropylphenol,
Orthobutylphenol, orthononylphenol and the like can be exemplified, but orthocresol is preferable in consideration of the raw material price, the reactivity at the time of novolak formation described later and the like.
The specific resole derived from the ortho-substituted phenol, that is, the dimethylol derivative as the main component represented by the general formula (2) and / or the general formula (3) is, for example, ESGran.
ger, Industrial and Engineering Chemistry, 24 , 442,
(1932) or F. Hanus, Journalfr Praktiche Chem
It can be easily obtained by adopting the method described in the literature such as ie, 155 , 317 (1940). More specifically, formaldehyde or formaldehyde generating substance 1.5 to 2.5 mol per 1 mol of the ortho-substituted phenols in the presence of an alkali catalyst such as sodium hydroxide or potassium hydroxide at about 10 to 60 ° C. The specific resol (A) can be obtained by performing a methylolation reaction for about 1 week to several hours. The amount of the alkali catalyst used is usually 0.8 to 1.2 times, preferably 0.9 to 1.1 times the molar amount of the phenols. The above-mentioned formaldehyde generating source substance refers to various substances such as paraformaldehyde, trioxane and tetraoxane which generate formaldehyde under resolization conditions. In the above, when the use amount of formaldehyde and the source substance is less than 1.5 mol, the production amount of the monomethylol body of the ortho-substituted phenols is increased, and as a result, the dimethylol of the general formulas (2) and (3) is obtained. The yield of the derivative will decrease. The monomethylol body does not become the trinuclear body or tetranuclear body of the present invention even if it undergoes the subsequent novolakization step, and it is not preferable because it produces a binuclear body. On the other hand, if the amount exceeds 2.5 mols, unreacted formaldehyde will be present in a large amount, which requires washing with water and increases the cost, which is not preferable. The reaction product obtained by this method is usually used as it is as an unpurified oily product, but it can also be used after purification.

Examples of the bifunctional or higher functional phenols (B) as the other raw material in the present invention include, in addition to carboxylic acids, alkyl-substituted phenols such as cresol and xylenol, halogenated phenols such as chlorophenol and bromophenol, and the like. To be Of these, folic acid and cresol are preferable in consideration of reactivity. Here, the functional number means the number of active positions capable of reacting with formaldehyde present in a molecule of phenols.

In the method of the present invention, the specific resol (A) and the bifunctional or higher functional phenols (B) are first heated and reacted in the presence of an acid catalyst. The acid catalyst used here is not particularly limited and any of various kinds used in ordinary novolak reaction can be used. Of these, oxalic acid is particularly preferable. The amount of the phenols used with respect to the resole is determined on the basis of the amount of the ortho-substituted phenols used as a raw material for producing the resole, and is 1.1 to 20 times the molar amount of the ortho-substituted phenols, preferably 3 to Ten
It is preferable to use a double molar amount. That is, in the present invention, by using an excess of the phenols with respect to the resole as described above, the condensation reaction between the methylol groups present in the resole is suppressed, and the formation of a high molecular weight component of pentanuclear or higher is minimized. It is what is suppressed to the limit. When the amount of the bifunctional or higher functional phenols used is less than 1.1 times the molar amount, the content of the high molecular weight component having 5 or more nuclides in the obtained target product increases, and the melt viscosity of the target product tends to increase. Therefore, it is not preferable. If the amount exceeds 20 times the molar amount, it is not preferable because the polydispersity is not significantly reduced even if the amount exceeds the above range and the polydispersity is further increased.

The reaction conditions are appropriately determined in consideration of the reactivity between the resole and the phenols, but usually about 50 to 100 ° C,
Preferably, a temperature condition of about 60 to 80 ° C. can react and a temperature of about 3 to 6
It is preferable to heat at the above temperature for a time. Further, in order to remove ionic impurities existing in the reaction product, the reaction product may be appropriately washed with water several times.

In the present invention, dehydration and demonomer are then performed. Demonomer mainly removes the unreacted phenols (B). Dehydration and demomerization are specifically carried out according to ordinary distillation operations. This distillation method is not particularly limited and may be any of various known methods such as vacuum distillation, thin film distillation and steam distillation.

Thus, according to the present invention, a desired polyhydroxy compound having a total content of trinuclear and tetranuclear bodies of 45% by weight or more and a polydispersity of 1.20 or less and a narrow molecular weight distribution can be obtained. . When the content is 45% by weight or less, the polydispersity is usually 1.20 or less, and by using this,
The flow characteristics and the like at the time of molding, which is the object of the present invention, are exhibited.

The polyhydroxy compound obtained by the method of the present invention has the following general formula: (In the formula, R ¹ is the same as the above. R ² and R ³ each represent a hydrogen atom, an alkyl group or a halogen atom.) And / or the general formula (In the formula, R ¹ , R ² and R ³ are the same as above.) It is presumed to be a phenol novolak resin mainly composed of a trinuclear body or a tetranuclear body when converted into a phenol nucleus. In the general formulas (4) and (5), R ² and R ³ are derived from the phenols (B).

The polyhydroxy compound obtained by the method of the present invention is very useful as a curing agent for epoxy resins. When used as the curing agent, the polyhydroxy compound of the present invention contains various epoxy resins and, if necessary, a curing accelerator,
It is mixed with other additives and the like to give an epoxy resin composition, which can be suitably used for applications such as a sealing material for electronic parts, a laminated board, and a powder coating material. Further, the polyhydroxy compound can be used as a polyol component for polyurethane or as an epoxy resin raw material.

EFFECTS OF THE INVENTION The polyhydroxy compound obtained by the method of the present invention has a low melt viscosity due to its narrow molecular weight distribution width (1) when compared with a conventional novolak resin having the same softening point. Therefore, (2) when it is used as a curing agent for an epoxy resin, the viscosity of the compound is reduced, and the workability during molding is significantly improved. Further, (3) the glass transition point of a cured product obtained by curing with an epoxy resin is higher than that of a conventional novolak resin having the same softening point, so that the heat resistance of the cured product is improved. It is effective.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these examples. In each example, all parts and percentages are by weight unless otherwise specified.

Example 1 After replacing the inside of a 500 ml flask equipped with a stirrer, a thermometer and a cooler with nitrogen gas, 54 g (0.5 mol) of orthocresol and 81 g (1 mol) of 37% formalin were added and stirred under a nitrogen stream. While keeping the temperature at 30 ° C., 200 g of 10% aqueous sodium hydroxide solution (0.5 mol as NaOH) was added dropwise. After keeping the temperature at the same temperature for 1 hour, it was further heated at 50 ° C. for 1 hour to carry out a methylolation reaction. Then, the mixture was cooled to 30 ° C. and neutralized with 123 g of 20% sulfuric acid (0.25 mol as H ₂ SO ₄ ) to obtain 89 g of oily resol. To 89 g of the resol, 162 g (1.5 mol) of orthocresol and 1 g of oxalic acid were added, a condensation reaction was carried out at 75 ° C. for 4 hours, dehydration was further performed under reduced pressure, and demonomerization was carried out by steam distillation to obtain unreacted orthocresol. The content was adjusted to 0.5% or less to obtain 115 g of the polyhydroxy compound of the present invention. This is called compound A.

Example 2 The reaction was performed in the same manner as in Example 1 except that the amount of orthocresol used in the novolakization reaction was increased to 270 g to obtain 120 g of a polyhydroxy compound having a phenol monomer content of 0.5% or less. This is called compound B.

Example 3 The same reactor as in Example 1 was replaced with nitrogen gas, 54 g of orthocresol and 81 g of 37% formalin were added, and the mixture was kept at 30 ° C. with stirring under a nitrogen stream and 200 g of 10% aqueous sodium hydroxide solution. Was dripped. Then, the mixture was heated to 65 ° C., and methylolation reaction was carried out at the same temperature for 4 hours. After that, cool to 30 ° C and neutralize with 123 g of 20% sulfuric acid.
86 g was obtained. Orthocresol 16 to the resol 86 g
Add 2g and 1g of oxalic acid and carry out condensation reaction at 75 ℃ for 4 hours.
Furthermore, dehydration was performed under reduced pressure, and demomer was performed by steam distillation to adjust the unreacted orthocresol content to 0.5% or less, to obtain 112 g of the polyhydroxy compound of the present invention. This is called compound C.

Example 4 In Example 3, the same reaction was performed except that the amount of orthocresol used in the novolak formation reaction was increased to 270 g, and 114 g of unreacted polyhydroxy compound having an orthocresol content of 0.5% or less was obtained. Obtained. This is compound D
Say.

Comparative Example 1 After replacing the inside of a 1-volume flask equipped with a stirrer, a thermometer and a condenser with nitrogen gas, 378 g (3.5 mol) of orthocresol, 213 g (2.63 mol) of 37% formalin and oxalic acid 3.
8g was added, and the reaction was carried out at reflux temperature for 3 hours under nitrogen flow.
Then, dehydration was performed under reduced pressure, and dephenol was performed by steam distillation to adjust the unreacted orthocresol content to 0.5% or less to obtain 367 g of a polyhydroxy compound.
This is called compound E.

Comparative Example 2 The reaction was performed in the same manner as in Comparative Example 1, except that the amount of 37% formalin used was reduced to 187 g, and 355 g of a polyhydroxy compound having an unreacted orthocresol content of 0.5% or less.
Got This is called compound F.

Comparative Example 3 The reaction was performed in the same manner as in Comparative Example 1 except that 121 g of 37% formalin and 48.5 g of 92% paraformaldehyde were used in place of 213 g of 37% formalin, and the reaction was carried out in the same manner. 390 g of hydroxy compound was obtained. This is called compound G.

Comparative Example 4 The reaction was performed in the same manner as in Comparative Example 1 except that the amount of 37% formalin used was increased to 263 g, and 383 g of a polyhydroxy compound having an unreacted orthocresol content of 0.5% or less.
Got This is called compound H.

Table 1 and Table 1 show the results of the properties of the various polyhydroxy compounds obtained in Examples 1 to 4 and Comparative Examples 1 to 4 above.
~ Fig. 4 shows.

In Table 1, the melt viscosity was measured under the conditions of a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) and a small amount of sample adapter, a sample amount of 10 g, an HM type rotor No. 2 and 150 ° C.
The softening point is obtained by the ring and ball method. The content of each component and Mw / Mn are columns (Toyo Soda Co., Ltd., "TSK gel G-
2000HxL "and" G-1000HxL "are connected in series, and a high-performance liquid chromatograph measuring device (manufactured by the same company," HLC-802 "
0 ”), and data processing was performed by“ CP-8000 ”manufactured by the same company. Further, the glass transition point was measured by a measuring device manufactured by Rigaku Denki Kogyo Co., Ltd. by the TMA (Thermo Mechanical Analysis) method. still,
100 parts of liquid epoxy resin ("Epicote 828" manufactured by Yuka Shell Epoxy Co., Ltd.), 63 parts of various polyhydroxy compounds obtained in Examples or Comparative Examples, and 2-methylimidazole 1
The parts were uniformly mixed and cured at 175 ° C. for 2 hours, and the cured product was used as a sample piece to measure the Tg of the cured product.

As is clear from Table 1, the polyhydroxy compounds obtained by the method of the present invention have lower melt viscosities than those of the comparative examples having almost the same softening point, and therefore, the workability in various applications is high. It is clear that it will improve. Further, since the cured product has a high Tg, the cured product has improved heat resistance, mechanical properties and the like.

1 to 4 show the molecular weight distributions of each of Compound B, Compound D, Compound F, and Compound H measured by using a high performance liquid chromatograph measuring apparatus ("HLC-8020" manufactured by Toyo Soda Co., Ltd.). In the graph, the horizontal axis represents elution time and the vertical axis represents peak intensity. In Figures 1 and 2, the tetranuclear body has peak No. 2 and the trinuclear body has peak N.
Corresponds to o.3. 3 and 4, both are 4
Nucleus corresponds to peak No. 3 and trinuclear corresponds to peak No. 4.

As is clear from the comparison between the figures, the polyhydroxy compound obtained by the method of the present invention (FIGS. 1 and 2) has a molecular weight distribution higher than that of the compound obtained in the comparative example (FIGS. 3 and 4). Is narrow, and it is understood that the main components are trinuclear bodies and tetranuclear bodies.

[Brief description of drawings]

1 to 4 are graphs in which the molecular weight distributions of the polyhydroxy compounds obtained in Examples 2 and 4 of the present invention and the polyhydroxy compounds obtained in Comparative Examples 2 and 4 were determined.

Claims (1)

[Claims] 1. A general formula (In the formula, R ¹ represents an alkyl group having 1 to 10 carbon atoms), obtained by reacting 1 mol of an ortho-substituted phenol with 1.5 to 2.5 mol of formaldehyde or a formaldehyde source material under alkaline conditions. Resol (A), difunctional or higher functional phenols (B),
Condensation under acidic conditions at a ratio of 1.1 to 20 times the molar amount of the ortho-substituted phenols used in the production of (A), further dehydration and demonomerization to give a trinuclear body and a tetranuclear body. Total content is 45% by weight or more and polydispersity is 1.20
A method for producing a polyhydroxy compound, which comprises obtaining the following polyhydroxy compound.