JPS598290B2 - Shinkina Polycarbonate Materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing flame-retardant polycarbonate, and more specifically, to a polycarbonate oligomer obtained by reacting an aromatic dioxy compound with phosgene, tetrahalogenohydroquinone or tetrahalogenohydroquinone is added. The present invention relates to a novel method for producing polycarbonate, which is characterized by condensing a mixture of polycarbonate and an aromatic dioxy compound.

The polycarbonate obtained by the present invention is new,
It contains specially selected tetrahalogenohydroquinone as a copolymerization component, so it has excellent flame retardancy and
It has excellent properties such as good tensile strength and no resin dripping even when burned.

The polycarbonate oligomer used in the method of the present invention can be prepared by blowing phosgene into a mixture of an aromatic dioxy compound such as bisphenol A dissolved in an aqueous solution of caustic soda and a solvent such as methylene chloride while stirring the mixture to a pH range of 9 to 12. At this point, the introduction of phosgene is stopped, and the aqueous layer and organic layer are separated by standing to obtain a solvent-soluble bran.

At this time, by appropriately controlling the reaction conditions, the molecular weight of the oligomer and the ratio of hydroxyl groups to chloroformate groups in the molecule can be adjusted as desired. The novel polycarbonate according to the present invention can be obtained by condensing such a polycarbonate oligomer with a tetrahalogenohydroquinone such as tetrachlorohydroquinone or tetrabromohydroquinone alone or in the form of a mixture with an aromatic dioxy compound.

The aromatic dioxy compounds which are raw materials for producing the copolymerized polycarbonate in the present invention include 4,4'-dioxydiphenyl-2,2-propane, 4,4L dioxydiphenyl-1|1-butane, 4 , 4'-dioxydiphenyl-1|4,4'-dioxydiphenylalkane such as 1-cyclohexane, 4,4'-dioxydiphenyl sulfone, 4,4L dioxydiphenyl sulfoxide, 4,4'- Dioxydiphenyl ether and the like are used.

The condensation reaction in the present invention is carried out in the presence of a catalyst in an organic solvent that can dissolve the polycarbonate oligomer and the polycarbonate produced. Tertiary amines such as trimethylamine, triethylamine, tripropylamine, and tributylamine are used as catalysts. Although the reaction proceeds with quaternary ammonium salts, the reaction rate is extremely slow and is not practical. In the method of the present invention, a molecular weight regulator may be used in combination if necessary. Examples of the molecular weight regulator include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and butyl alcohol, and phenols such as phenol, cresol, and butylphenol. type is appropriate. In addition, as a solvent, chlorinated hydrocarbons such as tetrachloroethane, trichloroethane, dichloroethane, trichlorethylene, dichloroethylene, chloroform, methylene chloride, chlorobenzene, dichlorobenzene, dioxane, cyclic oxyhydrocarbons such as tetrahydrofuran, etc. Compounds etc. are used. To carry out the present invention preferably, a tubular reactor is used, into which the alkaline aqueous solution of the aromatic dioxy compound and the organic solvent for polycarbonate are continuously introduced to form a multiphase flow, and phosgene is added to the reactor. The mixture is injected and reacted under external cooling while contacting cocurrently.

When the reaction is carried out in this way, the multiphase flow formed inside becomes a spray flow due to the reaction heat caused by the injection of phosgene.
Since contact with phosgene occurs in the state of this spray flow, phosgene reacts in almost the stoichiometric amount, and the reaction is completed in an extremely short time.

In addition, due to the reaction heat generated at this time, a part of the organic solvent is vaporized and becomes vapor, and on the other hand, the solvent in which the oligomer is dissolved and the aqueous solution containing alkali chloride become atomized, but these are removed from the reaction tube by external cooling. It gradually condenses as it approaches the outlet, and is finally taken out as a two-phase multiphase flow consisting of an organic layer containing oligomers and an aqueous layer containing alkali chloride and the remaining alkali. This product can be separated into two phases by allowing it to stand for a while. Introducing phosgene into a multiphase flow of an alkaline aqueous solution of an aromatic dioxy compound and an organic solvent can be done using a single inlet, but in large equipment, it is necessary to slow down the progress of the reaction locally. is possible,
It is advantageous to use two or more inlets to avoid waste of phosgene. In the tubular reactor, the length of the tube should be sufficiently long compared to the tube diameter (for example, tube length/tube length) so that the vaporized solvent can be completely condensed and the generated oligomers can be completely dissolved in the solvent. The diameter ratio is set to 8 or more) and a jacket or cooling tank is attached to the outside of the tube to enable external cooling. In this way, by using a tubular reactor and operating under predetermined reaction conditions, oligomers having a stable molecular weight range can be continuously obtained. For example, by reacting bisphenol A and phosgene in a methylene chloride solvent and maintaining the final reaction product in a slightly alkaline state, oligomers having a molecular weight of 450 to 500 can be obtained with good reproducibility. Next, the oligomer thus obtained is treated with a tetrahalogenohydroquinone or a mixture of an aromatic dioxy compound and a tetrahalogenohydroquinone in an alkaline aqueous solution, a catalyst such as a tertiary amine, and an optional molecular weight regulator such as a branched alkyl-substituted phenol. Add, cool externally, and react while stirring.

In this way, a thermally stable solution of flame-retardant polycarbonate in an organic solvent is obtained.

To recover polycarbonate from this solution, add an organic solvent to this polycarbonate solution to give a concentration of 6 to 801.
, and then washed with water to remove the inorganic substances contained therein. Then, a precipitant is added to precipitate the polycarbonate. Precipitants used in this case include aliphatic hydrocarbons such as pentane, hexane, heptane, and cyclohexane, aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol, and aliphatic ketones such as acetone and methyl ethyl ketone. These can be used alone or in combination of two or more. In the method of the present invention, the amount of halogen introduced into the target product can be adjusted as appropriate by changing the ratio of tetrahalogenohydroquinone to oligomer or the mixing ratio of aromatic dioxy compound and tetrahalogenohydroquinone. .

According to the present invention, any polycarbonate having a halogen content of 30% or less can be obtained. The polycarbonate obtained according to the present invention is flame retardant and has significantly improved thermal stability, so that even when molded at high temperatures, undesirable phenomena such as foaming do not occur and a homogeneous product is obtained. It is suitable as a molding material for parts, machine parts, building materials, miscellaneous goods, etc.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 and Comparative Examples A separable flask with an internal volume of 11 equipped with a stirrer, a thermometer, and a Ribrax condenser was charged with 500 cc of a 1.7N aqueous sodium hydroxide solution, and bisphenol A919 was added thereto and dissolved. Then, 200 cc of methylene chloride was added, and while stirring, phosgene was blown in at a flow rate of 409 cc/hour.

In this case, cool the flask from the outside to lower the reaction temperature to 2.
It was kept at 0°C. After 95 minutes, the pH of the reaction solution became 11.5, and at this point, the blowing of phosgene and stirring were stopped, and the reaction solution was separated into two layers by standing still.

The upper layer was an aqueous solution containing sodium chloride, which was removed by decanting to obtain a solution of bisphenol A polycarbonate oligomer in methylene chloride. The average degree of polymerization of this oligomer was about 1.8. Next, 250 CC of methylene chloride was further added to this oligomer solution to dilute it.
To this diluted solution, add 1 part of 2.0 N aqueous sodium hydroxide solution.
A solution of tetrachlorohydroquinone 409 and sodium hydrosulfide 0.59 dissolved in 60CC, 4
8% sodium hydroxide aqueous solution 18.0CC1 paratertiary butylphenol 3.2f1 and Triel-n
-Butylamine (0.19 g) was added and stirred for 90 minutes while maintaining the temperature at 30°C.

By this operation, the chloroformate groups were completely reacted and a sticky emulsion solution was obtained. This solution was diluted with methylene chloride to give a polymer concentration of 7%, and washed with water until the inorganic salts disappeared to obtain a transparent solution of copolymerized polycarbonate in methylene chloride. This was precipitated with methanol to obtain a polymer powder. After drying the body, the chlorine content was measured to be 14.9%, which corresponds to 27 mol% of tetrachlorohydroquinone. The copolymerized polycarbonate had an intrinsic viscosity of 0.43 d1/g when measured at 20° C. using methylene chloride as a solvent. Next, the copolymerized polycarbonate thus obtained was dissolved again in methylene chloride and casted to a thickness of 0.
．． I made a 12mm film. On the other hand, a homopolycarbonate of bisphenol A obtained by the reaction of bisphenol A and phosgene was formed into a film by the same casting method, and the tensile strength and oxygen index of both films were measured.

The results are shown below. In addition, the oxygen index in this case is JI
It was measured in accordance with SK-7201-72 and provides a flame retardant evaluation standard for resins, with a higher number indicating better flame retardancy. Example 2 In Example 1, 40 g of tetrachlorohydroquinone
A copolymerized polycarbonate powder was obtained by conducting the same experiment except that a mixture of 19.8 g of tetrachlorohydroquinone and 8.2 g of bisphenol Al was used instead.

Claims (1)

[Claims] 1. A novel method for producing flame-retardant polycarbonate, which comprises condensing tetrahalogenohydroquinone or a mixture of tetrahalogenohydroquinone and an aromatic dioxy compound with a polycarbonate oligomer obtained by reacting an aromatic dioxy compound with phosgene. .