KR19990011849A - Manufacturing method of flame retardant polycarbonate - Google Patents

Abstract

The present invention relates to a polycarbonate manufacturing method comprising the step of reacting bisphenol A and phosgene, by using a phenolic compound containing bromine and nitrogen to impart flame retardancy to the polycarbonate and at the same time containing the bromine and nitrogen The phenolic compound is characterized by acting as a molecular weight regulator. According to the method according to the invention, it is possible to produce flame retardant polycarbonates having a glass transition temperature similar to that of general polycarbonates and having a molecular weight of 20,000 to 30,000.

Description

Process for producing flame retardant polycarbonate

The present invention relates to a method for producing a flame retardant polycarbonate, and more particularly, to a method for producing a flame retardant polycarbonate, characterized by using a molecular weight modifier containing bromine and nitrogen capable of imparting flame retardancy while controlling molecular weight. will be.

Polycarbonate is a polymer having high impact strength, excellent numerical stability, thermal stability, and optical properties, and is used in soundproof walls, windows, and lenses requiring less dust pollution for building materials requiring transparency. Polycarbonates are generally obtained by reacting bisphenolA with phosgene and have a glass transition temperature of 150 ° C to 155 ° C. Recently, as the application range of polycarbonate is expanded to architecture, automobiles, aircrafts, etc., flame retardancy is required. Conventional methods of flame retardant polycarbonate include reactive and additive types.

Inorganic-added flame retardant primarily serves to separate the organics from the heat source by reducing the proportion of organic matter that can be burned. In addition, those with high specific heat and endothermic decomposition reactions serve as thermal sinks and interfere with combustion in the gas phase by non-combustible gases generated during decomposition.

The addition type flame retardant polycarbonate reaction type mainly uses sulfuric acid such as Li, Na, K, Mg and the like. However, the alkali metal-based flame retardant has a problem of causing hydrolysis in the polycarbonate when forming the polycarbonate at a high temperature. In addition, when using them, there is a disadvantage in that a drip inhibitor and a gas flame retardant generated during combustion must be added.

Phosphorus compounds of the phosphorus-based flame retardants promote carbide production in the condensed phase and form glassy coatings to hinder combustion and act as thermal outlets by endothermic reactions through the impression. Triphenylphosphineoxide and triphenylphosphate have recently been found to act as radical scavengers of oxygen and hydrogen in the gas phase. When using an additive flame retardant containing phosphorus, it shows a tendency to lower the heat deformation temperature of the polycarbonate and lower the impact strength. In the case of the reactive phosphorus flame retardant, it is known that the bond between phosphorus and oxygen has a base effect by hydrolysis to decompose the carboxyl group of the polycarbonate to lower the molecular weight.

Furthermore, there is a method of flame retardant by inserting a halogen element such as bromine, chlorine in the polycarbonate, since such an addition-type halogen-based flame retardant acts only as a flame retardant, in order to obtain a polymer compound of a desired molecular weight, a molecular weight regulator is added separately. There was a problem that should be.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a flame retardant polycarbonate in which a phenolic reactive flame retardant containing halogen and nitrogen is used to impart flame retardancy to the polycarbonate, and the reaction flame retardant can also act as a molecular weight regulator. .

In order to achieve the above object, the present invention is a polycarbonate manufacturing method comprising the step of reacting bisphenol A and phosgene, by using a phenol compound containing bromine and nitrogen to impart flame retardancy to the polycarbonate It is characterized in that the phenol-based compound containing bromine and nitrogen acts as a molecular weight regulator.

In addition, in the method for producing a flame retardant polycarbonate according to the present invention, the addition amount of the phenol compound containing bromine and nitrogen is 1 to 3 mol% based on the bisphenol A.

In the above-described method for producing a flame retardant polycarbonate according to the present invention, the phenolic compound containing bromine and nitrogen is 5,7-dibromo-8-hydroxy-quinoline, 2-methyl-5,7-di It is characterized in that it is selected from the group consisting of bromo-8-hydroxy- quinoline, and 2-bromopyridine.

Hereinafter, a method for producing a flame retardant polycarbonate according to the present invention will be described in detail.

In the present invention, a phenol compound containing bromine and nitrogen is used as a flame retardant for imparting flame retardancy to a polycarbonate produced by a reaction between bisphenol A and phosgene. Preferred as such a phenol compound containing bromine and nitrogen is 5,7-dibromo-8-hydroxy-quinoline (5,7-dibromo-8-hydroxy-qunoline) as shown in the following formula (1), 2-methyl-5,7-dibromo-8-hydroxy-quinoline (2-methyl-5,7-dibromo-8-hydroxy-qunoline) as shown in Formula 2, and 2-bromopyridine as is.

The chemical formulas of the polycarbonates obtained by using the phenolic compounds containing bromine and nitrogen according to the present invention as described above as flame retardants and molecular weight modifiers are shown in the following formulas (4) to (6).

In Chemical Formulas 4 to 6, n represents the number of monomers, and the molecular weight of the polycarbonate prepared by the method according to the present invention is in the range of 20,000 to 30,000.

The above-mentioned phenolic compounds containing bromine and nitrogen used as flame retardants and molecular weight regulators in the polycarbonate obtained by the production method according to the present invention have the following functions.

Since gas such as hydrogen halide or water is generated during combustion of the produced polycarbonate, it reduces the contact area with oxygen and dilutes the concentration of the combustible gas generated when the polycarbonate is decomposed. It stops the continuous decomposition of polycarbonate because it must react with radicals to become water.

In addition, since the terminal group of the prepared polycarbonate has an aromatic phenol structure containing bromine, the thermal stability is superior to that of the polycarbonate using parabutyl phenol.

The following are examples illustrating a method of preparing a flame retardant polycarbonate using the compounds of Chemical Formulas 1 to 3 as flame retardants and molecular weight modifiers, and test results of flame retardancy of the prepared flame retardant polycarbonates. For the flame retardancy test of the flame retardant polycarbonates prepared in the following examples, the test sample was prepared by injection molding in the 300 ℃ region, flame retardancy test was carried out according to UL-94. In addition, the viscosity average molecular weight (Mv) was measured using methylene chloride as a solvent at 20 ° C using a ubeloid viscometer.

First embodiment

In a 1 L three-necked flask, 60 g (0.263 mol) of bisphenol A was dissolved in 330 ml (18.46 g, 0.462 mol) of 5.6% by weight aqueous sodium hydroxide solution, and 26.0 g (0.263 mol) of phosgene was collected in 200 ml methylene chloride, and then a Teflon tube. Into the 1L three-necked flask through 20m slowly to react. At this time, the external temperature is maintained at 0 ℃. The reactant passed through the tubular reactor is reacted for about 10 minutes in a liquid nitrogen environment to obtain an oligomer having a molecular weight of about 3000. As flame retardant and molecular weight regulator, 2.24 g of 5,7-dibromo-8-hydroxy-quinoline of formula 1 (3 mol% relative to bisphenolA) was added to the reaction mixture, and 0.014 g of triethylamine was added as a reaction catalyst. After the reaction, react for about 30 minutes. Thereafter, the aqueous phase and the organic layer were separated and purified, and 60 ml of distilled water, 80 ml of methylene chloride, 8 g of sodium hydroxide, and 0.025 g of triethylamine were added to the organic layer and reacted for about 2 hours to obtain a flame retardant polycarbonate. 120 ml of methylene chloride is added to extract the flame retardant polycarbonate polymer, and then washed three times with 0.1 normal hydrochloric acid, followed by washing with distilled water until neutral. 800 ml of acetone and distilled water (1: 1) are slowly added to the flame retardant polycarbonate to obtain a small particle flame retardant polycarbonate. The polycarbonate was dried at 130 ° C. for 24 hours to determine the glass transition temperature and molecular weight. Glass transition temperature was 162 degreeC, and molecular weight was 32,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₀ .

Second embodiment

As a flame retardant and a molecular weight modifier, 5,7-dibromo-8-hydroxy-quinoline of the formula (1) was added in the same manner as in the first embodiment, except that 2.5 mol% of bisphenolA was added. The measured glass transition temperature was 162 ° C. and the molecular weight was 28,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Third embodiment

As flame retardant and molecular weight modifier, 5,7-dibromo-8-hydroxy-quinoline of the formula (1) was added in the same manner as in the first embodiment, except that 1.5 mol% of bisphenolA was added. The measured glass transition temperature was 159 ° C. and the molecular weight was 21,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Fourth embodiment

As flame retardant and molecular weight modifier, 2-methyl-5,7-dibromo-8-hydroxy-quinoline of formula (2) was added at 3.0 mol% relative to bisphenolA, except that To perform. The measured glass transition temperature was 162 ° C. and the molecular weight was 32,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₀ .

Fifth Embodiment

As flame retardant and molecular weight modifier, 2-methyl-5,7-dibromo-8-hydroxy-quinoline of the formula (2) was added in the same manner as in the first embodiment except that 2.5 mol% of bisphenolA was added. To perform. The measured glass transition temperature was 162 ° C. and the molecular weight was 28,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Sixth embodiment

As flame retardant and molecular weight modifier, 2-methyl-5,7-dibromo-8-hydroxy-quinoline of formula (2) was added at 1.5 mol% based on bisphenolA, except that To perform. The measured glass transition temperature was 159 ° C. and the molecular weight was 21,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Seventh embodiment

The same procedure as in Example 1 was carried out except that 2-bromo-pyridine of Formula 3 was added in an amount of 3.0 mol% based on bisphenol A as a flame retardant and a molecular weight regulator. The measured glass transition temperature was 159 ° C. and the molecular weight was 32,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Eighth embodiment

The same procedure as in Example 1 was carried out except that 2-bromo-pyridine of Formula 3 was added in an amount of 2.5 mol% based on bisphenol A as a flame retardant and a molecular weight regulator. The measured glass transition temperature was 159 ° C. and the molecular weight was 28,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

9th Embodiment

The same procedure as in Example 1 was performed except that 2-bromo-pyridine of Formula 3 was added in an amount of 1.5 mol% based on bisphenol A as a flame retardant and a molecular weight regulator. The measured glass transition temperature was 157 ° C. and the molecular weight was 21,000. The flame retardancy according to the UL-94 flame retardancy test was found to be V ₁ .

Tenth Example: Comparative Example

1.0 mol% of 5,7-dibromo-8-hydroxy-quinoline of Formula 1 used in Examples 1, 2 and 3 as a flame retardant and a molecular weight modifier was added to bisphenol A. Except that, it is carried out in the same manner as in the first embodiment described above. The measured glass transition temperature was 163 ° C. and the molecular weight was 37,000. Low flame retardancy

Example 11 Comparative Example

5.0 mol% of 5,7-dibromo-8-hydroxy-quinoline of the formula (1) used in Examples 1, 2 and 3 as a flame retardant and a molecular weight modifier was added to bisphenol A. Except that, it is carried out in the same manner as in the first embodiment described above. The measured glass transition temperature was 157 ° C. and the molecular weight was 10,000.

Example 12: Comparative Example

10.0 mol% of 5,7-dibromo-8-hydroxy-quinoline of Chemical Formula 1 used in Examples 1, 2 and 3 as a flame retardant and a molecular weight modifier was added to bisphenol A. Except that, it is carried out in the same manner as in the first embodiment described above. The measured glass transition temperature was 150 ° C. and the molecular weight was 4,500.

The results obtained by the above embodiments are shown in Tables 1 and 2 below.

Physical Properties of Polycarbonates Prepared by a Manufacturing Method According to Preferred Embodiments of the Present Invention Example # Used flame retardant ^a Amount of flame retardant used ^b (mol%) Bromine / nitrogen content ^c (mass%) Glass transition temperature Molecular Weight Flame retardancy One Formula 1 3.0 1.86 162 32,000 V ₀ 2 Formula 1 2.5 1.55 162 28,000 V ₁ 3 Formula 1 1.5 0.93 159 21,000 V ₁ 4 Formula 2 3.0 1.98 162 32,000 V ₀ 5 Formula 2 2.5 1.65 162 28,000 V ₁ 6 Formula 2 1.5 0.99 159 21,000 V ₁ 7 Formula 3 3.0 0.74 159 32,000 V ₁ 8 Formula 3 2.5 0.62 159 28,000 V ₁ 9 Formula 3 1.5 0.37 157 21,000 V ₁

a: Formula 1: 5,7-dibromo-8-hydroxy-quinoline

Formula 2: 2-methyl-5,7-dibromo-8-hydroxy-quinoline

Formula 3: 2-bromo pyridine

b: mole% for bisphenolA

c: content of bromine and nitrogen in the produced polycarbonate

Physical Properties of Polycarbonates Prepared by a Manufacturing Method According to Comparative Examples Example # Used flame retardant ^a Amount of flame retardant used ^b (mol%) Bromine / nitrogen content ^c (mass%) Glass transition temperature Molecular Weight Flame retardancy 10 Formula 1 1.0 0.62 163 37,000 lowness 11 Formula 1 5.0 3.1 157 10,000 V ₀ 12 Formula 1 10.0 6.2 150 4,500 V ₀

a: Formula 1: 5,7-dibromo-8-hydroxy-quinoline

b: mole% for bisphenolA

c: content of bromine and nitrogen in the produced polycarbonate

As shown in Table 1 and Table 2 above, 5,7-dibromo-8-hydroxy-quinoline (Formula 1), 2-methyl-5,7-dibromo-8-hydroxy-quinoline ( In the method for producing a polycarbonate using a phenolic compound containing bromine and nitrogen of the formula (2) and 2-bromo pyridine (formula 3) as a flame retardant and a molecular weight regulator, 1.0 to 3.0 moles of the compound relative to bisphenol A In the case of using%, the molecular weight was in the range of about 20,000 to 30,000, and a polycarbonate having a flame retardancy could be prepared. The flame retardancy was low due to the low bromine and nitrogen content in the polycarbonate, and the compound was prepared by using 5 mol% or more of bisphenol A as in the eleventh and twelfth examples. The high bromine and nitrogen content in the polycarbonate increases the flame retardancy, but the molecular weight reaches 10,000 or less, making it impossible to use as a polymer.

As described above, the present invention provides a method for producing a flame retardant polycarbonate using a phenol compound containing bromine and nitrogen as a flame retardant and a molecular weight regulator. In the method for producing a flame retardant polycarbonate according to the present invention, since the used phenol-containing compound containing bromine and nitrogen simultaneously serves as a flame retardant and a molecular weight regulator, a viscosity increase during polymerization occurs in the polycarbonate manufacturing process, thereby causing a post-polymerization treatment process. This can compensate for process problems that are difficult to remove and eliminate residual alkali. In addition, the polycarbonate produced by the present invention has an aromatic phenol structure containing bromine at the end group of the polycarbonate is excellent in heat safety than polycarbonate using para butyl phenol. In addition, according to the method according to the present invention, a flame retardant polycarbonate having a glass transition temperature similar to that of a general polycarbonate and having a molecular weight of 20,000 to 30,000 can be produced.

Claims (3)

In the polycarbonate manufacturing method comprising the step of reacting bisphenol A and phosgene, A method for producing a flame retardant polycarbonate, wherein a phenolic compound containing bromine and nitrogen is used to impart flame retardancy to the polycarbonate and the phenolic compound containing bromine and nitrogen acts as a molecular weight regulator. The method for producing a flame retardant polycarbonate according to claim 1, wherein the amount of the phenol compound containing bromine and nitrogen is 1 to 3 mol% based on the bisphenol A. According to claim 1, wherein the bromine and nitrogen-containing phenolic compound is 5,7-dibromo-8-hydroxy-quinoline, 2-methyl-5,7-dibromo-8-hydroxy-quinoline And 2-bromopyridine.