JPS6399215A - Production of 4,4'-thiodiphenol type novolak - Google Patents

Abstract

PURPOSE:To obtain a 4,4'-thiodiphenol type novolak having proper molecular weight efficiently without gelatinizing, by reacting 4,4'-thiodiphenol with formaldehyde in a specific ratio by the use of an organic solvent in the presence of an acidic catalyst. CONSTITUTION:4,4'-Thiodiphenol is reacted with formaldehyde (preferably aqueous solution of formalin) by the use of an organic solvent (e.g. isobutyl alcohol, etc.) capable of dissolving 4,4'-thiodiphenol, having 90-160 deg.C boiling point at normal pressure in the presence of an acidic catalyst (e.g. oxalic acid, etc.) in a molar ratio of formaldehyde/4,4'-thiodiphenol=0.5-1.3 to give 4,4'- thiodiphenol type novolak. The 4,4'-thiodiphenol type novolak has excellent reactivity with hexamethylenetetramine and various epoxy resins and is industrially useful.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a 4.4''-thiodiphenol type novolac.

[Conventional technology]

Generally, novolac resins obtained by reacting phenols and formaldehyde under an acidic catalyst are thermosetting resins that are widely used as molding materials, various binders, or as curing agents for epoxy resins using hexamethylene and amine as a curing agent. It is resin.

Many techniques are known for the production of Novock using phenols such as phenol, cresol, xylenol, and bisphenol A, but 4.4'-
There are few documents regarding the production method of novolak using thiodiphenol as a raw material. For example, J. Prakt, Ch.
Em, 19.303-308 (1963) discusses the reactivity of 4,4°-thiodiphenol with formaldehyde under an alkali catalyst;
From the viewpoint of the production method of 4'-thiodiphenol type novolak, this method is far from an industrial technology.

[Problem that the invention seeks to solve]

An object of the present invention is to efficiently produce a 4,4°-thiodiphenol type novolac having an appropriate molecular weight without causing gelation.

Means for Solving Problem C] In order to achieve the above object, the present inventors conducted extensive studies and finally arrived at the present invention.

That is, the present invention uses 4,4'-thiodiphenol (T) and formaldehyde (F) at a molar ratio of F/T.
4,4゛-thiodiphenol is soluble in the DPO range of 95 to 1.3 and has a boiling point of 90°C or higher and 160°C at normal pressure.
This is a method for producing a 4,4'-thiodiphenol type novolak in which a reaction is carried out under an acidic catalyst using the following organic solvent.

Since the 4,4'-thiodiphenol used in the present invention is tetrafunctional with respect to formaldehyde, it tends to gel during the reaction. Also, it is a powder solid at room temperature and has low solubility in water, so an aqueous formalin solution is used as the formaldehyde source. Even if the molar ratio F/TDP O, 5 to 1.3
The preparation conditions require some kind of reaction solvent. Is formaldehyde formalin water? g'j(
1. Although any solid paraformaldehyde can be used, the former is preferred because the latter generally has low solubility in organic solvents.

Examples of the acidic solvent used in the present invention include oxalic acid, hydrochloric acid, sulfuric acid, para-toluenesulfonic acid, zinc chloride, etc., which are commonly used in the synthesis of novolacs, and the amount used is appropriately determined depending on the acid strength of the catalyst.

The organic solvent used in the reaction of the present invention is soluble in 4.4°-thiodiphenol and has a boiling point (b, p,) of 9 at normal pressure.
Isobutyl alcohol (b, p
, los °C), n-butanol (b, p, 117.5 °C
), n-pentanol (b, p, 138.3°C), n
-Alcohol necks such as hexanol (b, p, 157.9°C), diethyl ketone (b, p, 101.7°C), methyl isobutyl ketone (b, p, 115.9°C), acetylacetone (b, p, 137°C) and cyclohexanone (b, p, 156°C). If the boiling point of the organic solvent is below 90°C, a sufficient reaction temperature cannot be obtained, and if it is above 160°C, it becomes difficult to remove the solvent. Further, the amount of organic solvent used may be sufficient to dissolve 4°4'-thiodiphenol.

Details of the manufacturing method of the present invention will be described below.

First, a predetermined amount of 4,4°-thiodiphenol, formaldehyde, an acidic catalyst, and an organic solvent are charged into a reactor all at once. Here, the molar ratio F/TCP is 0.5 to 1.3,
If it is less than 0.5, a large amount of unreacted 4.4゛-thiodiphenol remains and it is impossible to obtain a novolak with an appropriate molecular weight, and if it is more than 1.3, there is a risk of gelation during the reaction. be. As mentioned above, the 6i catalyst is commonly used in the synthesis of novolak, and the amount of the catalyst to be charged is determined depending on the type of acidic catalyst. The amount of organic solvent charged is 4.
It is sufficient to dissolve 4゛-thiodiphenol, and it varies depending on the preparation conditions and the type of organic solvent, but it is 30 to 100P for 414゛-thiodiphenol.
HR is preferred.

Next, the temperature is gradually raised while stirring to carry out the reflux reaction for 3 to 6 hours.
Make time work. The continuous flow temperature is preferably 90 to 105°C, and the reflux reaction is carried out until the formaldehyde reaction rate is about 50 to 90%. While dehydrating and removing solvent at normal pressure, the temperature inside the reactor is 150 to 105°C. Gradually raise the temperature until it reaches 170°C. Finally, the indoor bath is 150~17
Maintain the temperature at 0°C and remove the organic solvent in the reactor with 1 g of reduced pressure until it is completely removed, then cool and solidify to obtain the desired 4°4°-thiodiphenol type novolac. .

〔Example〕

The present invention will be explained below with reference to Examples.

<Example 1> 4.4゛-thiodiphenol 218g, 37% formalin aqueous solution 89.3g <molar ratio 1.1), oxalic acid 2.18g
g, 87.2 g of n-butanol was reacted under reflux at 100°C for 5 hours, and the reaction rate of formaldehyde at this point was 59.2%.9 Next, while dehydrating and removing solvent at normal pressure, The temperature was raised until the internal temperature reached 160° C., and while the internal temperature was maintained at 160 to 165° C., the solvent was removed at a reduced pressure of 7 mmHg for 2 hours to allow cooling. The resulting resin was a dark purple solid with a yield of 227.4
It was g. The softening point according to JIS K2531 is 94.
The temperature was 9°C.

A gel permeation chromatography (GPC) chromatogram is shown in FIG. 1, and a nuclear magnetic resonance absorption (NMR) spectrum is shown in FIG. 2.

The numbers shown in Figure 1 indicate the number of nuclei of novolac resin homologs, and the peak indicating unreacted 4,4゛-thiodiphenol is relatively low compared to other peaks (novolac resin indicates that it is manufactured.

A and BSC shown in Figure 2 indicate signals of phenolic hydroxyl group, aromatic pronto, and methylene bond, respectively, and 8
．． Phenolic hydroxyl group around 6ppm, 7.3-6.8
Aromatic pronto near ppm, 3. A methylene bond signal was observed near qppm, and the target substance was 4.4°-
It can be determined that it is a thiodiphenol type novolac. Further, the number average molecular weight calculated from the GPC chromatogram was 826, and the average degree of condensation was 3.64.

<Example 2> 218 g of 4.4°-thiodiphenol, 56.8 g of 37% formalin water W solution (molar ratio 0.7), 1.09 g of para-toluenesulfonic acid-methyl isobutyl ketone 109
g was reacted under reflux at 100° C. for 3 hours. The reaction rate of formaldehyde at this point was 84.6%.Next, while dehydration and solvent removal were carried out at normal pressure, the internal temperature was reduced to 1.
Raise the temperature to 60℃, then increase the internal temperature to 160-165℃
The solvent was removed for 2 hours at a reduced pressure of 10 mmHg while maintaining the temperature at °C, and the mixture was cooled and solidified. The resulting resin was a dark purple solid, and the yield was 213.6 g. JIS K2531
The softening point was 97.4°C.

gel? The chromatogram of l+3 chromatography ([;PC) is shown in FIG. FIG. 3 shows that novolac resin is produced.

<Comparative Example 1> 4.4゛-thiodiphenol 218 g, 37% formalin aqueous solution 109.6 g (molar ratio 1.35), oxalic acid 2.
18g, n-butanol 87.2g under reflux
The reaction was carried out at ℃ for 5 hours. The formaldehyde reaction rate at this point was 57.5%. Next, while dehydrating and removing solvent at normal pressure, the temperature was gradually increased.
Gelation occurred when the internal temperature reached 158°C.

<Comparative Example 2> 218 g of 4.4'-thiodiphenol, 37% formalin water? g t&32, 5 g (molar ratio 0.4)
, paratoluenesulfone M (1.09 g), and methyl isobutyl ketone (109 g) were reacted under reflux at 100° C. for 5 hours. The formaldehyde reaction rate at this point was 88.
Next, while dehydrating and removing solvent at normal pressure, the temperature was increased until the internal temperature reached 160°C, and the degree of vacuum was reduced to 8 mmHg while maintaining the internal temperature at 160 to 165°C.
The solvent was removed for 2 hours. After that, when it was cooled and solidified, when the internal temperature reached 140℃, 4.4
°, thiodiphenol crystals began to precipitate. The GPC chromatogram revealed that more than 40% of 4.4'-thiodiphenol remained unreacted in the resin.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it is possible to efficiently produce a 4,4'-thiodiphenol type novolak having an appropriate molecular weight without gelation. Also, 4,
Thiodiphenol-type novolacs have a high reactivity with behexamethylene and various epoxy resins compared to ordinary phenol-type novolacs, and are industrially useful.

Table 1 shows the gel time according to JIS K6910.

[Brief explanation of the drawing]

Table 1 Unit (sec) 1) 12 PHR for novolak 2) Hydroxyl group/epoxy group -1/1, Shikoku Fine Chemical Co., Ltd.'s 2-undecylimidazole as a curing accelerator was used for IPHR for epoxy resin. FIG. 1 is a GPC chromatogram of the 4,4'-thiodiphenol type novolafuku obtained in Example 1. FIG. 2 is an NMR spectrum diagram of the 4,4'-thiodiphenol type novolafuku obtained in Example 1. FIG. 3 is a GPC chromatogram of the 4,4″-thiodiphenol type Novolafuku obtained in Example 2. Patent applicant: Mitsui Toatsu Chemical Co., Ltd. FIG. 1 ÷-m-count High molecular weight-1. Figure 2 Chemical shift (P Pm) Figure 3 ←---Count High molecular weight -
〉1. Indication of the case 4,4"-Production method of thiodiphenol type novolak 3. Person making the amendment Relationship with the case Patent applicant address 3-2-5 Kasumigaseki, Chiyoda-ku, Tokyo Name (31
2) Mitsui Toatsu Kagaku Co., Ltd. 4. The number of inventions increased by the amendment 5. Date of the amendment order 7. Explanation of the contents of the amendment” section was deleted, and the first line of page 11 added “4. Insert a section titled “Explanation”.

Claims (1)

[Claims] 4,4'-thiodiphenol (TDP) and formaldehyde (F) are mixed at a molar ratio F/TDP in the range of 0.5 to 1.3 so that 4,4'-thiodiphenol is soluble and has a boiling point at normal pressure. 4, characterized in that the reaction is carried out under an acidic catalyst using an organic solvent with a temperature of 90°C or more and 160°C or less;
Method for producing 4'-thiodiphenol type novolak.