JPS62119220A - Production of polyhydroxyl compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound having extremely low content of low- molecular condensate and narrow molecular weight distribution and suitable as an epoxy resin hardener, by reacting a specific p-substituted phenol dimethylol derivative with a phenolic compound in the presence of an acid under heating. CONSTITUTION:(A) p-Substituted phenol dimethylol derivative consisting of 2,6-dihydroxymethyl-4-alkylphenol or 2,6-dihydroxymethyl-4-arylphenol is made to react with (B) a phenolic compound (preferably phenol, etc.) in the presence of an acid catalyst (preferably oxalic acid) under heating preferably at 60-80 deg.C for 3-6hr. The reaction product is subjected to dehydration and removal of phenol to obtain the objective compound containing <=5wt% component having <=2 nuclei and >=30wt% trinucleus component. The amount of the component B is preferably 1.5-3mol per 1mol of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel method for producing polyhydroxy compounds, and more particularly to a method for producing novel and useful polyhydroxy compounds having a narrow molecular weight distribution width.

Conventional technology Traditionally, amines,
Acid anhydrides, phenol novolac resins, etc. have been used, but in recent years, phenol novolac resins have been reconsidered for applications such as laminates and sealants due to demands for higher performance and lower prices of products. This resin is particularly suitable for use in electrical and electronic materials. Therefore, the phenol novolak resin is generally obtained by a condensation reaction of phenols and formaldehyde in the presence of an acid catalyst, and is a linear molecule mainly composed of 2 to 20 phenol nuclei linked by methylene bonds. It is believed that As the above-mentioned raw material phenols, carbolic acid, orthocresol, etc., which usually have one phenolic hydroxyl group, are used.
The resulting resin contains a low molecular weight component consisting of unreacted phenol monomer and binuclear bodies. For these reasons, when this resin is used as a curing agent, it is difficult to provide a cured product with a high crosslinking density, and the resulting cured product is therefore unsatisfactory in terms of heat resistance, chemical resistance, mechanical properties, etc. There is a drawback that it is not possible.

In addition, conventionally, (1) monohydric phenols such as carbolic acid and orthocresol, (2) rose-substituted phenols such as rose-substituted alkylphenol and rose-substituted arylphenol, and (3) formaldehyde were simultaneously charged and subjected to a condensation reaction. Rose-substituted phenol-based cocondensation novolac resins are also known, but, like the general phenol novolak resins mentioned above, these resins also have the effect of stopping the reaction of epoxy groups such as dinuclear acid of carbolic acid and para-substituted phenol heptamers. It contains low molecular weight components that are thought to act as agents, and cannot exhibit the desired curing properties.

Moreover, the co-condensed novolak resin generally has a wide molecular weight distribution, and even when the content of the carbolic acid monomer is adjusted to 1% by weight or less by distillation or other operations, Mw /Mn (M
(w indicates the layer average molecular weight value and Mn indicates the number average molecular weight value) exhibits a high value of 1.5 or more, and is disadvantageous as a curing agent in terms of handling and workability due to its melt viscosity.

Problems to be Solved by the Invention In view of the above-mentioned prior art, the present invention is directed to a new polyfunctional phenolic resin having excellent properties as a curing agent for epoxy resins, and more specifically, to a new polyfunctional phenolic resin having a significantly reduced content of low molecular weight condensates. It is an object of the present invention to provide a method for producing a polyfunctional phenolic resin with a reduced molecular weight distribution and a narrow molecular weight distribution width.

Means for Solving the Same Point The above object is to process a dimethylol derivative of a substituted phenol selected from 2,6-dihydroxymethyl-4-alkylphenol and 2,6-dihydroxymethyl-4-arylphenol and phenols using an acid catalyst. The content of components of binuclear bodies or less is 5% by weight or less, preferably 2.
This is achieved by a method for producing a polyhydroxy compound characterized by obtaining a polyhydroxy compound in which the content of the trinuclear component is 5% by weight or less and 30% by weight or more, preferably 40% by weight or more.

As a result of intensive research, the present inventors discovered that 2゜6-dihydroxymethyl-4-alkylphenol and 2,6
When using a dimethylol derivative of a rose-substituted phenol selected from -dihydroxymethyl-4-arylphenols as a starting material and reacting it with an excess of 111 phenols in the presence of an acid catalyst, it is then dehydrated and dehydrated by conventional distillation. It was discovered that the target compound could be obtained by removing phenol, and the present invention was thus completed.

The polyhydroxy compound obtained by the present invention contains almost no low-molecular weight component that functions as a reaction terminator for epoxy groups, and has a narrow molecular weight distribution, so it is very difficult to use as a curing agent for epoxy resins. exhibits excellent hardening properties,
It has a high crosslinking density and is characterized by providing cured products with excellent heat resistance, chemical resistance, mechanical properties, etc.

In the present invention, the dimethylol derivatives of rose-substituted phenol used as starting materials are typically, for example, 2.6-dihydroxymethyl-4-methylphenol, 2.6-dihydroxymethyl-4-ethylphenol, 2.6-dihydroxymethyl-4-ethylphenol, -dihydroxymethyl-4-n-propylphenol, 2゜6-dihydroxymethyl-4-isopropylphenol, 2,6-dihydroxymethyl-4-monobutylphenol, 2,6-dihydroxymethyl-4
-amylphenol, 2,6-dihydroxymethyl-4
-ocdylphenol, 2,6-dihydroxymethyl-
Examples include 4-phenylphenol. These rose-substituted phenol dimethylol derivatives can be produced according to conventional methods. For example 2,6-dihydroxymethyl-4
-Alkylphenol can be obtained as a highly pure solid by reacting the corresponding partially substituted alkylphenol with formaldehyde in the presence of water and a basic catalyst, followed by acid precipitation. In addition, in the present invention, the above 2
, 6-dihydroxymethyl-4-alkylphenol, a resol-type oil obtained by neutralizing the reaction product of the above-mentioned rose-substituted alkylphenol and formaldehyde with acid, without any subsequent purification. You can also do it. 2.6-dihydroxymethyl-4
-7 Reel phenols can also be produced in the same manner as above.

The other raw material phenols in the present invention include, in addition to carbolic acid, rose- or ortho-substituted alkylphenols such as cresol and xylenol, and halogenated phenols such as chlorophenol and bromophenol. Among these, carbolic acid and cresol are preferred in consideration of reactivity.

In the method of the present invention, first, the dimethylol derivative of the above-described substituted phenol and a phenol are heated and reacted in the presence of an acid catalyst. The acid catalyst used here is not particularly limited, and any of the various types commonly used in the production of novolac resins can be used. Among these, oxalic acid is particularly suitable. The amount of phenol used for the rose-substituted phenol dimethylol derivative is an excess amount, usually about 1.2 to 10 times the molar amount, preferably about 1.5 to 3.0 times the molar amount, relative to the methylol group possessed by the derivative. It is better to This amount is approximately 2.4 for the above derivative itself.
This corresponds to a range of ~20 times the molar amount. If the amount of the phenol used is much less than 1.2 times the mole of the methylol group, the softening point and melt viscosity of the obtained target product will increase, which is undesirable.

The above reaction conditions are appropriately determined taking into account the amount of unreacted phenol, the amount of low-molecular condensation products, the amount of high-molecular condensation products, etc. caused by the reaction, but are usually about 50 to 100°C, preferably about 60 to 80°C. Any temperature condition may be employed, preferably heating at the above temperature for about 3 to 6 hours.

In the present invention, dehydration and dephenolization are then performed. This can be carried out in particular according to conventional distillation operations.

This distillation method is not particularly limited, and any of various known methods such as vacuum distillation, thin film distillation, steam distillation, etc. may be used. However, this distillation operation hardly removes condensates of two or more nuclear bodies. In the present invention, as described above, by using an excess of phenols with respect to the dimethylol derivative of the rose-substituted phenol, the condensation reaction between the methylol groups of the derivative is suppressed, and the formation of condensates of two or more nuclei is minimized. This is to suppress it.

Thus, according to the present invention, the content of components of binuclear bodies or less is 5
% by weight or less, and the content of trinuclear components is 30% by weight
or more (usually in the range of 30 to 80% by weight), and a desired polyhydroxy compound with a narrow molecular weight distribution width can be obtained.

The polyhydroxy compound obtained by the method of the present invention has a phenolic nucleus represented by the following general formula (1).
It is presumed to be a phenolic novolac resin mainly consisting of nuclear bodies.

H R1 (1) In the formula, R1 represents an alkyl group or an aryl group, R2 represents a hydrogen atom or an alkyl group, and R3 represents a hydrogen atom, an alkyl group, or a halogen atom. ] The above polyhydroxy compound obtained by the method of the present invention is very useful as a curing agent for epoxy resins. When used as a curing agent, the polyhydroxy compound of the present invention is blended with various epoxy resins and, if necessary, a curing accelerator and other additives to form an epoxy resin composition, which can be used, for example, to seal electronic parts. It can be suitably used for materials, laminates, powder coatings, etc. Furthermore, the polyhydroxy compound can also be used as a polyol component for polyurethane or as a raw material for epoxy resin.

EXAMPLES Hereinafter, the present invention will be explained in more detail by giving examples and comparative examples of the method of the present invention, but the present invention is not limited to these examples. In each example, all parts and percentages are based on weight unless otherwise specified.

Example 1 After purging the inside of a 1Q flask equipped with a stirrer, thermometer and condenser with nitrogen gas, 1,6-dihydroxymethyl-
210 parts (1 mol) of 4-t-butylphenol, 282 parts (3 mol) of carbolic acid, and 1.4 parts of oxalic acid were added and reacted at 70°C for 4 hours under a nitrogen stream, followed by dehydration under reduced pressure and steam distillation. to remove phenol and adjust the phenol monomer content to 1.0% or less,
A polyhydroxy compound of the present invention was obtained. This is called "compound A."

Example 2 A polyhydroxy compound having a phenol monomer content of 1.0% or less was obtained in the same manner as in Example 1, except that the amount of carbolic acid used was changed to 470 parts (5 moles). This is called "compound B."

Comparative Example 1 88 parts (2 mol) of coal Ml was placed in a 1Q flask equipped with a stirrer, thermometer, and cooler after purging with nitrogen gas.
, 122 parts (1.5 moles) of 37% formalin and 0.7 parts of oxalic acid were reacted under a nitrogen stream at reflux temperature for 3 hours, dehydrated under reduced pressure, and dephenolized by steam distillation. , phenol monomer content is 1.0%
A polyhydroxy compound was obtained by adjusting the following. This is called "comparative compound C."

The results of determining the properties of each polyhydroxy compound obtained in the above Examples and Comparative Examples are shown in Table 1 and Figures 1 to 3.

In Table 1, the content of each component and Mw /Mn are
(G-4000H8 and G-2000H8)
The softening point was determined using the ring and ball method.

Table 1 and FIGS. 1 to 3 show the high performance liquid chromatograph measuring device M for each of Compound A, Compound B, and Comparative Compound C.
(Manufactured by Toyo Shisokusha, HLC-802A, cp-8000)
1 is a graph showing the molecular weight distribution measured using a method, in which the horizontal axis shows the elution count number and the vertical axis shows the peak intensity.

As is clear from the comparison of each figure, the polyhydroxy compound obtained by the method of the present invention (Figures 1 and 2) has a narrower molecular weight distribution width than that obtained in the comparative example (Figure 3). ,
Furthermore, it can be seen that the main component is trinuclear bodies.

[Brief explanation of drawings]

1 to 3 are graphs showing the molecular weight distributions of the polyhydroxy compounds obtained in Examples 1 and 2 of the present invention and the polyhydroxy compound obtained in Comparative Example 1. (that's all)

Claims (2)

[Claims] (1) A dimethylol derivative of para-substituted phenol selected from 2,6-dihydroxymethyl-4-alkylphenol and 2,6-dihydroxymethyl-4-arylphenol is reacted with phenols by heating in the presence of an acid catalyst, and then A polyhydroxy compound obtained by dehydration and dephenolization to obtain a polyhydroxy compound in which the content of dinuclear components or less is 5% by weight or less and the content of ternary components is 30% by weight or more. Method of manufacturing the compound. (2) The method according to claim 1, wherein the molar ratio of the phenol to the dimethylol derivative of the para-substituted phenol is 2.4 to 20 times.