JPS5814450B2 - Manufacturing method of novolac type phenolic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novolak type phenolic resin.

Generally, novolak type phenolic resin is made of glass fiber,
It is used as a molding material by mixing it with a base material such as wood flour or asbestos and kneading it with a roll.

In this case, if a novolak type phenolic resin having a high softening point is used, the kneading properties with the base material will be poor, roll workability will be poor, and a uniform molding material will not be obtained.

As a result, the performance of the molded product also deteriorates.

Therefore, it has been proposed to solve such problems by lowering the softening point of novolak type phenolic resins.

That is, phenol (P) and almaldehyde (F)
By reducing the molar ratio (F)/(P) of
If F)/(P) is small, the molecular weight of the resulting resin will be small; conversely, if it is large, the molecular weight will be high and the softening point will be high.)
, it was proposed to attach a solvent.

However, although this method can lower the softening point of the novolac type phenolic resin (hereinafter referred to as novolac resin), a new problem has arisen in that the performance of molded products using it deteriorates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for producing a novolak resin that has a low softening point, good roll kneading properties, etc., and does not impair the performance of molded products.

In summary, the present invention is capable of increasing the softening point by adding an aryl compound having one epoxy group during or after synthesis when synthesizing a novolak resin by reacting phenols and aldehydes under an acidic catalyst. The objective is to obtain a novolak resin that has a low oxidation rate and does not impair the performance of molded products.

Next, the manufacturing method of this invention will be specifically explained.

First, phenol (P) and formaldehyde (F),
For example, they are blended so that the molar ratio (F)/(P) of the ingredients is 0.6 to 1.0.

Then, an aryl compound having one epoxy group, such as 2,4-dibromophenyl glycidyl ether, is further blended with this, and addition condensation is carried out under an acidic catalyst.

Thereafter, water and condensed water contained in formaldehyde are dehydrated while stirring with heating.

In this way, a novolak resin is produced.

In this case, an aryl compound having one epoxy group (
The epoxy compound (hereinafter referred to as epoxy compound) reacts with the phenolic OH groups of the novolak resin during the addition condensation or dehydration operation, or is completely dispersed in the novolak resin.

When it reacts with phenolic OH groups, it weakens the hydrogen bonds between molecules and lowers the softening point of the novolak resin.

Furthermore, even if no reaction occurs, the softening point is lowered by mixing.

That is, both of these effects lower the softening point of the novolak resin.

If all of the epoxy compound is to be completely reacted with the novolac resin, it is necessary to add a tertiary amine or a quaternary ammonium salt as a promoter and heat and stir.

However, it is not necessary to react all of the epoxy compounds in this manner.

Further, even if the epoxy compound is added after the synthesis of the novolak resin, it will exhibit almost the same effect as when added during the synthesis.

Therefore, an epoxy compound may be added and mixed when a novolak resin is synthesized in the usual manner and made into a molding material.

The amount of such an epoxy compound added varies depending on the softening point of the target novolac resin, but the amount of epoxy compound added is 0.005 to 0.2 per mole of charged phenol.
It is preferable to select moles.

If the amount added is less than this range, the effect will be small, and if it is more than this range, the curing speed will be slow when used as a molding material, or the crosslinking density will be low, resulting in adverse effects.

Further, the epoxy compound used in this invention is limited to one having one epoxy group.

That is, those having several epoxy groups crosslink and gel, and therefore cannot lower the softening point.

Below, epoxy compounds having one epoxy group used in the present invention are illustrated.

In order to completely react such an epoxy compound with a novolac resin, a tertiary amine or quaternary ammonium salt is required as a cocatalyst, as described above.

Examples of such promoter compounds are shown below.

As described above, the resin obtained by adding an epoxy compound during or after synthesis of novolak resin has a low softening point, and when used as a molding material, has good kneadability with the base material. It also has high fluidity during molding.

A molded article manufactured using such a molding material is excellent in all performances, particularly in dimensional stability under heat and heat resistance.

Next, examples will be described.

Example 1 Phenol 95g, 37% formaldehyde 60g, 1
%HCI 4 g was placed in a 500,772 liter flask, equipped with a stirring device and a reflux condenser, and then 2,4-
Add 1.7 g of dibromophenol glycidyl ether and 1.0 g of tetramethylammonium chloride, continue heating and stirring, and when 2 and a half hours have elapsed since reflux, attach a pressure reducing device to perform dehydration under reduced pressure, and further heat and stir. The contents were taken out when the temperature reached 150°C.

As a result, 102 g of solid resin was obtained.

The softening point of this material was 95°C.

Next, using this, a molding material is made using the usual method,
We also made molded products.

In this case, roll kneading was easy and molded product performance was also good.

Example 2 94 g of phenol, 60 g of 37% formaldehyde,
0.6 g of oxalic acid was placed in a 500 ml flask, a stirrer and a reflux condenser were attached, heating and stirring were continued, and after 2 and a half hours had elapsed after reflux, dehydration was performed under reduced pressure.

After the resulting resin reached 150°C, the temperature was maintained for another 30 minutes, then 1.8g of 4-methylphenyldimethylbenzalglycidyl ether and 0.8g of N,N-dimethylformamide were added, and the temperature was further raised to 160°C.
The mixture was heated and stirred for 2 hours to obtain 100 g of solid resin.

The softening point of this material was 97°C.

Then, a molded article was made using this in the same manner as in Example 1.

In this case, roll kneading was easy and molded product performance was also good.

Example 3 In Example 2, when the temperature of the resulting resin reached 150°C, 2 g of 2,4-dibromophenol glycidyl ether was added.

Other than that, the solid resin (softening point 98
°C) and used it to make molded products.

In this case, roll kneading was easy and molded product performance was also good.

Example 4 In Example 2, when the temperature of the produced resin reached 150°C, 2.6 g of benzhydryl glycidyl ether
and 1.5 g of N,N-dimethylformamide were added.

Other than that, the solid resin (softening point 96
°C) and used it to make molded products.

In this case, roll kneading was easy and molded product performance was also good.

Example 5 In Example 2, when the temperature of the resulting resin reached 150°C, 1.7 g of 2,4-dibromophenol glycidyl ether and 0.8 g of triethylamine were added.

Other than that, the solid resin (softening point 97
°C) and used it to make molded products.

In this case as well, roll kneading properties and molded product performance were good.

Comparative Example In Example 1, addition of the epoxy compound and cocatalyst was omitted.

A solid resin was obtained in the same manner as in Example 1 except for the above.

The softening point of this material was 105°C.

Next, a molded article was produced in the same manner as in Example 1 using this.

In this case, the roll kneading properties were poor and the molded product performance was also poor.

Claims (1)

[Claims] 1. When synthesizing novolak-type phenolic resin by reacting phenols and aldehydes under an acidic catalyst,
During or after synthesis, add an aryl compound having one epoxy group to 0.005 to 1 mole of phenol.
A method for producing a novolak type phenolic resin, characterized in that it is added in a range of 0.2 mol.