JPS5922734B2 - Method for producing copolymerized flame-retardant polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a copolymerizable flame-retardant polycarbonate, and more specifically, the present invention relates to a method for producing a copolymerized flame-retardant polycarbonate.
This invention relates to a method for producing a copolymerizable polycarbonate with excellent fluidity.

In recent years, in order to enhance the flame retardancy of polycarbonate made from bisphenol A, tetrabromo bisphenol A has been copolymerized and tetrabromo bisphenol A has been copolymerized.
A method has been developed in which a copolymerized polycarbonate of bisphenol A and bisphenol A is mixed (Japanese Patent Publication No. 7116/1983).

However, when comparing copolymers with the same intrinsic viscosity, these copolymers had the disadvantage that they had lower melt fluidity than bisaenol A polycarbonate, making molding difficult. Therefore, the present inventors overcame the drawbacks of the above-mentioned prior art, and without impairing the flame retardancy and mechanical properties of a copolymerized polycarbonate of bisphenol A and tetrahalogenated bisphenol A,
We conducted extensive research to improve its fluidity and processability.

As a result, the inventors discovered that the objective could be achieved by blending a specific aromatic dioxy compound in the process of producing the copolymerized polycarbonate, and completed the present invention. That is, the present invention provides a polycarbonate oligomer obtained by reacting bisphenol A and phosgene with (a) tetrahalogenated bisphenol A or tetrahalogenated bisphenol A and bisphenol A and (b) 4,4' - A copolymerizable flame-retardant polycarbonate with improved fluidity, characterized by condensing a mixture of one or more compounds selected from the group consisting of dihydroxybenzophenone, hydroquinone, and bisphenol F. The present invention provides a method for manufacturing.

The polycarbonate oligomer used in the method of the present invention is prepared by combining bisphenol A [scientific name: bis-121 (4-hydroxyphenyl)-propane] dissolved in an alkaline aqueous solution such as caustic soda and an organic solvent such as methylene chloride. A solvent solution can be obtained by blowing phosgene into the mixture while stirring the mixture, stopping the introduction of phosgene when the pH reaches a range of 9 to 12, and separating the aqueous layer and the organic layer by standing. 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 copolymerized polycarbonate according to the method of the present invention is produced by adding (a) tetrahalogenated bisphenol A or tetrahalogenated bisphenol A and bisphenol A to the polycarbonate oligomer obtained as described above, and (b) 4,4 '-dihydroxybenzophenone, hydroquinone, and bisphenol F [scientific name: bis-1(4-hydroxyphenyl)-methane], mixing and condensing one or more compounds selected from the group consisting of It can be obtained by

Here, tetrahalogenated bisphenol A is tetrapromubisphenol A [scientific name: 2-bis-(3,5-
dibromo-4-hydroxyphenyl)-propane], tetrachlorbisphenol A [scientific name: 2-bis-(3
, 5-dichloro-4-hydroxyphenyl)-propane] and the like, and there is no particular restriction on its amount, but the proportion in the copolymerized polycarbonate that is produced is usually 1 to 20 moles. It is preferable to mix them so that
If it is less than 1 mol e, sufficient flame retardance cannot be obtained, and if it is 20 mol e or less, sufficient flame retardance cannot be obtained. If this is the case, physical properties, particularly mechanical properties, will deteriorate.

Note that the amount of bisphenol A added together with tetrahalogenated bisphenol A is not particularly limited, and may be added as appropriate as required. On the other hand, other substances to be added to the oligomer 1, such as 4,4'-dihydroxybenzophenone, hydroquinone, or bisphenol F, are all added for the purpose of improving the fluidity of the resulting copolymerized polycarbonate in the molten state. These compounds may be used alone or in combination of two or more.

Here, the blending amount of these compounds is not particularly limited and is determined depending on the fluidity, moldability, etc. of the desired copolymerized polycarbonate, but generally, the proportion in the copolymerized polycarbonate to be produced is 1 to 20 moles. ? , preferably 5 to 20 mol? It should be made so that 1 mole?
If it is less than 20 mol, it is not possible to sufficiently improve the fluidity of the product. Above this, the mechanical properties deteriorate.

The condensation reaction in the present invention is polycondensation, and is usually carried out in the presence of a catalyst in an organic solvent that can dissolve the polycarbonate oligomer and the copolymerized polycarbonate to be produced.

As a catalyst, trimethylamine, triethylamine,
Tertiary amines such as tripropylamine and tributylamine are preferably used. Although the reaction proceeds with quaternary ammonium salts, the reaction rate is extremely slow and is not practical. Incidentally, during the condensation, a molecular weight regulator may be used in conjunction with the condensation, if necessary. Examples of the molecular weight regulator include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and butyl alcohol, phenol, cresol, and butyl phenol. Phenols such as are suitable. Examples of solvents include chlorinated hydrocarbons such as tetrachloroethane, trichloroethane, dichloroethane, trichlorethylene, dichloroethylene, chloroform, methylene chloride, chlorobenzene, and cyclobenzene, and cyclic oxy compounds such as dioxane and tetrahydrofuran. used. Furthermore, it is preferable to add an antioxidant such as hydrosulfide as necessary. To carry out the present invention preferably, a tubular reactor is used, into which an alkaline aqueous solution of bisphenol A and an organic solvent for polycarbonate are continuously introduced to form a multiphase flow, and phosgene is injected into the reactor. The reaction is carried out under external cooling while bringing them into cocurrent contact.

When the reaction is carried out in this way, the multiphase flow formed inside becomes a spray stream due to the reaction heat caused by the injection of phosgene, and contact with phosgene occurs in this spray stream, so that
Phosgene reacts in almost stoichiometric amounts, and the reaction is completed in an extremely short time. Further, due to the reaction heat generated at this time, a part of the organic solvent is vaporized and becomes vapor. On the other hand, the solvent in which oligomer 1 is dissolved and the aqueous solution containing alkali chloride form a spray, but these gradually condense toward the outlet of the reaction tube due to external cooling, and finally form an organic layer containing oligomer 1. It is extracted as a two-liquid multiphase flow consisting of aqueous layer containing alkali chloride, 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 bisphenol A and an organic solvent can be carried out using a single inlet, but if two or more inlets are used, it may be difficult to introduce phosgene locally in large equipment. This is advantageous because it can slow down the progress of the reaction and prevent 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, oligomers having a molecular weight of 450 to 500 can be obtained with good reproducibility by reacting bisphenol A and phosgesoin in a methylene chloride solvent and maintaining the final reaction product in a slightly alkaline state. Next, (a) tetrahalogenated bisphenol A or tetrahalogenated bisphenol A and bisphenol A are added to the oligomer thus obtained.
and (b) 4,4'-dihydroxybenzophenone,
A mixture of hydroquinone or bisphenol F is added as an alkaline aqueous solution together with a catalyst, such as a tertiary amine, and optionally a molecular weight regulator such as a branched alkyl-substituted phenol, and the reaction is allowed to proceed with external cooling and stirring.

In this way, a solution of the desired copolymerizable polycarbonate in an organic solvent is obtained.

To separate the polycarbonate from this solution, add an organic solvent to the polycarbonate solution to make a solution with a concentration of 6 to 8%, wash with water to remove the inorganic substances contained therein, and then remove the precipitant. If the mixture is precipitated in addition, polycarbonate powder can be obtained as a precipitate.
In this case, precipitants include aliphatic hydrocarbons such as pentane, hexane, heptane, and cyclohexane, aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol, acetone,
Aliphatic ketones such as methyl ethyl ketone are used alone or in combination of two or more. The copolymerized polycarbonate obtained as described above has excellent mechanical strength and flame retardancy, and also exhibits good fluidity in a molten state, making it suitable for molding.

Therefore, this polycarbonate can be extremely suitably used as a molding material for electrical parts, building materials, miscellaneous goods, and other fields where flame retardancy is required. Next, examples of the present invention will be shown.

Example 1 Internal volume 1 fitted with stirrer, thermometer and reflux condenser
500 cc of 1.7 N aqueous sodium hydroxide solution was charged into a separable flask of
Add 9l9 and dissolve, then add 200cc of methylene chloride.
was added, and phosgene was bubbled in at a flow rate of 409/hr while stirring.

In this case, cooling was performed from the outside of the flask to maintain the reaction temperature at 20°C. After 95 minutes, the... of the reaction solution was 11.5.
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. Next, this oligomer solution was further diluted with 250 cc of methylene chloride, and this diluted solution was added with 1 cc of 2.0N sodium hydroxide aqueous solution.
60CC with tetraprombisphenol A449 and 4,
A solution containing 199% of 4'-dihydroxybenzophenone and 0.59% of sodium hydrosulfide, 4
8? Sodium hydroxide aqueous solution 18.0CC1 para-tertiary butylphenol 3.2f! and triethylamine 0.
19 was added and stirred for 90 minutes while maintaining the temperature at 30°C.

Through this operation, the chloroformate groups were completely reacted, and a viscous emulsion solution was obtained. This solution was diluted with methylene chloride to give a polymer concentration of 7%, and washed with water until all inorganic salts were removed, yielding a transparent methylene chloride solution of the copolymerized polycarbonate. This was precipitated with methanol and dried to obtain copolymerized polycarbonate 1509. The molecular weight of this polymer is shown in Table 1.
Next, the bromine content of the copolymerized polycarbonate obtained as described above was measured and found to be 8.0%.

Further, this copolymerized polycarbonate was dissolved again in methylene chloride, and a film having a thickness of about 0.1 nm was prepared by casting. A tensile test and an oxygen index measurement were performed using this film. The results are shown in Table-1. Further, the flow values measured according to JIS-K-6719-1969 are shown in Table 2. Example 2 Methylene chloride solution (diluted) of bisphenol A polycarbonate oligomer prepared in the same manner as Example 1
Then, in 160 cc of 2.0 N aqueous sodium hydroxide solution, tetraprombisphenol A449, hydroquinone 109 and sodium hydrosulfide 0.59
A solution of 48% sodium hydroxide aqueous solution18.
0CC, 3.29% para-tert-butylphenol and 0.19% triethylamine were added, and the mixture was heated to 9°C while maintaining the temperature at 30°C.
The reaction was allowed to proceed for 0 minutes.

Thereafter, the same operations as in Example 1 were performed to obtain 1409 copolymerized polycarbonate. The molecular weight, bromine content, tensile strength, elongation and oxygen index of this polycarbonate are shown in Table 1, and the flow value is shown in Table 2. Example 3 A methylene chloride solution (diluted) of bisphenol A polycarbonate oligomer produced in the same manner as in Example 1 was added with 160C of a 2.0 N aqueous sodium hydroxide solution.
C contains tetraprombisphenol A449, bisphenol Fl89 and sodium hydrosulfide 0
．． 59, 18.0 CC of 48% aqueous sodium hydroxide solution, 3.29 CC of para-tert-butylphenol and 0.19 of triethylamine were added, and the mixture was reacted with stirring for 90 minutes while maintaining the temperature at 30°C.

Thereafter, the same procedure as in Example 1 was carried out to obtain 1509 copolymerized polycarbonate. The molecular weight, bromine content, tensile strength, elongation and oxygen index of this polycarbonate are shown in Table 1, and the flow value is shown in Table 2.

Comparative Example 1 In the same manner as in Example 1, bisphenol A3 was added to a methylene chloride solution of bisphenol A polycarbonate oligomer.
When only 79 was added and the reaction was carried out in the same manner as in Example 1, 1309 bisphenol A polycarbonate was obtained.

The molecular weight, tensile test, and oxygen index of this polymer were measured. The results are shown in Table-1. Comparative Example 2 In Comparative Example 1, tetraprombisphenol A889 was added instead of bisphenol A, and the following Example 1 was prepared.
When the reaction was carried out in the same manner as above, copolymerized polycarbonate 1609 was obtained.

The molecular weight of this polymer was 30,500 and the bromine content was 13.370. Further, a film having a thickness of about 0.1 m1 was prepared by casting this polymer. A tensile test and an oxygen index were measured using this film. The results are shown in Table-1. Comparative Example 3 In the same manner as in Comparative Example 2, tetrapromubisphenol A6O9 was added and reacted to obtain copolymerized polycarbonate 1409.

The flow value of this polymer is JIS-K-6719-196.
9. The results are shown in Table-2. Comparative Example 4 Tetrapromubisphenol A3 was prepared in the same manner as Comparative Example 2.
When O9 was added and reacted, copolymerized polycarbonate 1109 was obtained.

The flow values of this polymer are shown in Table 2. As is clear from Table 2 and the graph of the relationship between molecular weight and flow value of conventional polycarbonates shown in Figure 1 for reference, all of the polycarbonates of the examples have significantly improved fluidity compared to the conventional ones. It is recognized that

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between molecular weight and flow value of conventionally known bisphenol A homopolycarbonate and bisphenol A-tetraprom bisphenol A copolycarbonate.

Claims (1)

[Scope of Claims] 1 A polycarbonate oligomer obtained by reacting bisphenol A and phosgene contains (a) tetrahalogenated bisphenol A or tetrahalogenated bisphenol A and bisphenol A, and (b) 4,4'-dihydroxybenzophenone. A method for producing a copolymerizable flame-retardant polycarbonate with improved fluidity, comprising condensing a mixture of one or more compounds selected from the group consisting of , hydroquinone, and bisphenol F. 2. The manufacturing method according to claim 1, wherein the tetrahalogenated bisphenol A is tetrabromobisphenol A or tetrachlorbisphenol A. 3. The manufacturing method according to claim 1 or 2, wherein tetrahalogenated bisphenol A is blended in a proportion of 1 to 20 mol% in the copolymerized polycarbonate to be produced. 4. Blending one or more compounds selected from the group consisting of 4,4'-dihydroxybenzophenone, hydroquinone, and bisphenol F so that the proportion in the copolymerized polycarbonate to be produced is 1 to 20 mol%. A manufacturing method according to claim 1. 5. Blending one or more compounds selected from the group consisting of 4,4'-dihydroxybenzophenone, hydroquinone, and bisphenol F so that the proportion in the copolymerized polycarbonate to be produced is 5 to 20 mol%. A manufacturing method according to claim 1. 6. The manufacturing method according to claim 1, wherein a tertiary amine is used as a catalyst during the condensation.