JPS5912646B2 - Method for producing photo-stable brominated diphenyl ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing brominated diphenyl ether manufactured by Koni Tei Co., Ltd.

Recently, in Japan and other countries, the flame retardant properties of plastics have been carefully studied in two directions. Reduce flame retardancy by removing 1 to 3 bromines by cutting. *Production methods and application methods for various flame retardants are being studied.

It is already known that decabromidiphenyl ether and brominated diphenyl ether containing decabromidiphenyl ether as a main component are very effective as flame retardants for various plastics, especially for polyolefins such as polystyrene, polypropylene, It is an extremely useful flame retardant for making polyethylene flame retardant. Although the mechanical properties, thermal stability, and flame retardance of plastics made flame-retardant with brominated diphenyl ethers, which are mainly composed of decabromodiphenyl ether and decapro-10modiphenyl ether, are excellent, their biggest drawback is The problem is that the plastic changes color due to light, and as the color change progresses, the physical properties of the resin 15 gradually deteriorate, that is, the weather resistance is poor.

The present inventors have long studied in detail the deterioration mechanism caused by light of plastics made flame retardant by decabromodiphenyl ether and brominated diphenyl ether containing decabromodiphenyl ether as a main component. As an example, the following formula (I)
As shown in , some of the C-Br bonds in the bromine bonded to the benzene ring of decabromodiphenyl ether are very weak and are easily decomposed by light, especially ultraviolet light, to form carbon radicals and bromine radicals, and these radicals was found to attack the resin and accelerate its deterioration.

BrBrBr .

0°B to H-B-----Te((I)BrBrBr
Based on the idea that brominated diphenyl ether without Br35 and stable to light can be obtained, as a result of various studies, brominated diphenyl ether that is stable to light can be obtained by reacting it in an organic solvent in the presence of an oxidizing agent. They discovered that ether can be obtained and completed the present invention.

Therefore, the present invention provides a light-stable brominated diphenyl ether, which is characterized by reacting a brominated diphenyl ether containing decabromodiphenyl ether as a main component in an organic solvent in the presence of an oxidizing agent. This relates to a manufacturing method.

Although it has not yet been determined which position of the C-Br bond in decabromodiphenyl ether is to be cleaved in the method of the present invention, it is presumed that the C-Br bond is at the ortho position.

Incidentally, the radicals generated by the cleavage of the C--Br bond are extinguished by adding a radical terminator. The brominated diphenyl ether containing decabromodiphenyl ether as a main component, which is a raw material for the method of the present invention, can be obtained by brominating diphenyl ether with bromine by a commonly known method.

In the method of the present invention, the bromination reaction product of diphenyl ether is dissolved in an organic solvent or finely pulverized and suspended in an organic solvent, and then an oxidizing agent is added thereto and the product is heated at room temperature or under heating. After reacting for a certain period of time, usually from 15 minutes to 10 hours, a radical terminator is added, if necessary, to obtain a brominated diphenyl ether that is stable to light. The organic solvent used in the present invention includes:
Most commonly known organic solvents can be used, but particularly preferred solvents include benzene, toluene,
xylene, methanol, ethanol, isopropanol, butanol, hexane, heptane, acetone, methyl ethyl ketone, acetic acid, propionic acid, dichloroethane,
Trichloroethane, perchloroethane, dimethyl sulfoxide, dimethylformamide, ethylene glycol,
Examples include propylene glycol and methyl cellosolve. The amount of organic solvent used is preferably 1 to 100 parts by weight per 1 part by weight of brominated diphenyl ether.

Examples of the oxidizing agent used in the present invention include organic peroxides such as peracetic acid and benzoyl peroxide, permanganates, dichromates, perchlorates, chlorates, hypochlorites, and peroxides. Hydrogen, oleum, sulfuric anhydride, nitric acid, etc. are effective.

Generally, it is preferable to use these oxidizing agents in an amount of 0.1 to 10% by weight based on the brominated diphenyl ether starting material.

When the oxidizing agent is solid and insoluble or sparingly soluble in the organic solvent used in the present invention, it is pulverized and added. Even when a liquid oxidizing agent is used, it may be insoluble or sparingly soluble in the organic solvent, and the raw material may be insoluble or sparingly soluble, so the reaction is preferably carried out under stirring. The reaction temperature in the presence of the oxidizing agent is room temperature to the boiling point of the solvent.

When reacting at room temperature, it is generally necessary to lengthen the reaction time, depending on the type and amount of the oxidizing agent added; on the other hand, when reacting at or near the boiling point of the solvent, the reaction time may be shortened. After reacting in the presence of an oxidizing agent,
If the oxidizing agent contains water, the water acts as a radical stopper, and the resulting brominated diphenyl ether can be used as is as a light-stable flame retardant. If not, add a small amount of water to annihilate the radicals, or add a radical stopper such as 2,6-di-tert-butyl-1P-cresol, t-butyl anisole, or t-butyl catechol to annihilate the radicals. This gives a photo-stable brominated diphenyl ether.

The brominated diphenyl ether thus obtained can be
It is a compound that is particularly stable against ultraviolet light, and when used as a flame retardant in plastics, especially polyolefins such as polystyrene, polypropylene, and polyethylene, it is significantly superior to plastics containing brominated diphenyl ether simply recrystallized in an organic solvent. It was found that the material exhibited excellent weather resistance.

This will be explained below using an example.

Example 1 100 parts by weight of crude decabromodiphenyl ether obtained by brominating diphenyl ether with bromine was mixed with xylene 2
000 parts by weight was added and heated to 130°C to dissolve.

1 part by weight of 30% hydrogen peroxide solution was added to this and stirring was continued for 60 minutes. After cooling, the obtained crystals were separated from P and dried to obtain 90 parts by weight of prominated diphenyl ether. Analysis value C
:17.11% Br:80.81% Average composition: Cl2
Hl5Br8.5O Example 2 20 parts by weight of xylene was added to 100 parts by weight of crude decapromodiphenyl ether obtained by brominating diphenyl ether with bromine.
00 parts by weight was added and heated to 130°C to dissolve.

To this was added 0.5 parts by weight of benzoyl peroxide and continued stirring for 15 minutes, then 0.5 parts by weight of 2,6-ditertiarybutyl-P-cresol was added and cooled, and the resulting crystals were separated by P. After drying, 93 parts by weight of brominated diphenyl ether was obtained. Analysis value C: 16.38% Br: 81.8
5% average composition: Cl2HlBr9O Example 3 Crude brominated diphenyl ether obtained by brominating diphenyl ether (Cl5.5% Br82.7%, average composition C.

H. ．． , Br9.6O) to 100 parts by weight of hexane 500
After adding 10 parts by weight of 25% oleum to the mixture, stirring was continued at room temperature for 5 hours. Thereafter, 20 parts by weight of water were added and the mixture was further stirred for 15 minutes, and then the crystals were separated, washed with water and dried to obtain 86 parts by weight of brominated diphenyl ether. Analysis value C: 17.96 Br: 79.80%, average composition Cl2H2Br8O Example 4 1000 parts by weight of methanol was added to 100 parts by weight of crude decabromodiphenyl ether and heated to 60°C.

0.3 parts by weight of 60% sodium perchlorate was added to this suspension, and stirring was continued for 30 minutes. After cooling, the crystals were separated and dried to obtain 94 parts by weight of brominated diphenyl ether. Analysis value C: 16.35% Br: 82.03% Average composition C
12H, Br9O Reference Example To 100 parts of styrene resin, add 15 parts each of brominated diphenyl ether recrystallized from an organic solvent or brominated diphenyl ether reacted in the presence of an oxidizing agent according to the above example, Furthermore, a small amount of ultraviolet absorber, heat stabilizer, etc. are added, and the mixture is thoroughly kneaded and molded at a temperature of 240° C. or lower.

The obtained molded product was subjected to a weather resistance test using a weatherometer. The results are shown in the table. Furthermore, no influence of the added flame retardant was observed on the impact strength, heat distortion temperature, and other physical properties of the resin.

Claims (1)

[Claims] 1. A method for producing a light-stable brominated diphenyl ether, which comprises reacting a brominated diphenyl ether containing decabromodiphenyl ether as a main component in an organic solvent in the presence of an oxidizing agent.