JPH0617470B2 - Polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel polycarbonate, and more particularly to a polycarbonate excellent in flame retardancy, impact resistance and molding heat stability.

[Problems to be Solved by Prior Art and Invention]

Conventionally, various flame-retardant halogen-containing copolymer polycarbonates have been proposed, for example, a copolymer of tetrabromobisphenol A (TBA) and bisphenol A (BPA) (Japanese Patent Publication No. 47-24660). ), Tetrabromobisphenol sulfone (TB
Copolymer of S) and BPA (JP-A-51-123294)
Gazette), tetrabromotibiosphenol (TBT
Copolymer of DP) and BPA (JP-A-56-99226)
No.), a copolymer of a statistical mixture of halogenated bisphenol and BPA (JP-A-51-136796) or a copolymer of thiobisphenol (TDP) and BPA and the above-mentioned copolymer. (JP-A-54-
No. 50065) is known.

These copolymers are obtained by copolymerizing halogenated bisphenols in which the benzene nucleus of bisphenols is substituted with halogen in order to contain the amount of halogen required to impart flame retardancy. However, both of them have a problem that these halogenated bisphenols must be used in a relatively large amount, and accordingly, the mechanical strength (particularly impact resistance strength) of the polycarbonate must be sacrificed.

As another halogen-containing polycarbonate, one using a halogenated phenol as a terminal stopper is known (Japanese Patent Publication No. 46-40715). However, also in this case, it is not possible to impart both flame retardancy and mechanical strength.

As a method for improving the above drawbacks, BPA, TB
A polycarbonate in which A and TDP are copolymerized is known (Japanese Patent Laid-Open No. 140597/52). With this method, flame retardancy and mechanical strength can be imparted at the same time, but the moldability is not always sufficient.

The present inventor and his group use pentahalogenophenol as a terminal stopper as a novel polycarbonate excellent in flame retardancy and mechanical strength, and
And a copolymer obtained by copolymerizing TBA with TBA were proposed (Japanese Patent Laid-Open Nos. 64-79227 and 64-79).
No. 228). However, this polycarbonate is
Although it is excellent in flame retardancy and mechanical strength, it was found that there are some problems in thermal stability during molding.

Therefore, the present inventor has conducted earnest studies to develop a novel polycarbonate that is excellent in flame retardancy, mechanical strength, and the like, and is also excellent in thermal stability during molding.

[Means for Solving the Problems]

As a result, they have found that the above-mentioned problems can be achieved by using trihalogenophenol as a terminal stopper. The present invention has been completed based on such findings. That is, the present invention has the general formula [In formula, X < ¹ > -X < ⁴ > shows a halogen atom. ] The repeating unit (I) represented by In addition to having the repeating unit (II) represented by ^Wherein, X 5 to X ⁷ is a halogen atom. ] The trihalogenophenoxy group represented by the formula (1) is bonded, the viscosity average molecular weight thereof is 10,000 to 50,000, and the content of the repeating unit (I) in the main chain is 1 to 10 mol%. A polycarbonate is provided.

The polycarbonate of the present invention has the repeating unit (I) represented by the general formula (A) and the repeating unit (II) represented by the formula (B). Here, X ^{1 to} X ⁴ in the general formula (A) each represent a halogen atom such as a bromine atom, a chlorine atom and a fluorine atom. This X ^{1 to} X ⁴
May be the same or different, but they are usually the same in many cases.

Further, the polycarbonate of the present invention has a trihalogenophenoxy group represented by the general formula (C) bonded at the terminal positions of the molecule, particularly at both terminal positions. X ^{5 in} this general formula (C)
Similarly to X ^{1 to} X ⁴ , halogen atoms such as bromine atom, chlorine atom, and fluorine atom are also shown for X ⁷ to X ⁷ .

The repeating unit (I) represented by the above general formula (A)
X ^{1 to} X ⁴ therein and X ^{5 to} X ⁷ in the general formula (C) may be the same or different.

In the polycarbonate of the present invention, the repeating unit (I)
Regarding the mole fraction of the repeating unit (II), it is necessary that the content of the repeating unit (I) in the main chain is 1 to 10 mol%, preferably 2 to 6 mol%. When the content of the repeating unit (I) in the main chain is less than 1 mol%, the flame retardancy decreases, while when it exceeds 10 mol%, the mechanical strength decreases.

Further, regarding the degree of polymerization of the polycarbonate of the present invention, a viscosity average molecular weight in the range of 10,000 to 50,000 is suitable. If the viscosity average molecular weight is less than 10,000, mechanical strength such as impact resistance is not sufficient.

The polycarbonate of the present invention has the repeating unit (I),
It has (II) and has a structure in which a trihalogenophenoxy group of the general formula (C) is bonded at the terminal position, and there are various types such as random copolymers, block copolymers, and alternating copolymers. .

It should be noted that a small amount of repeating units other than the repeating units (I) and (II) may be mixed in the molecular chain of the polycarbonate. As a third comonomer constituting such other repeating unit, bisphenol sulfone (B
PS), TDP, etc. Its content (molar fraction)
Is 0 to 20 mol%, preferably 0 to 10 mol%, based on the total amount of BPA and TBA. This content is 2
If it exceeds 0 mol%, the mechanical strength decreases.

The polycarbonate of the present invention can be produced by various methods, and the following two methods can be given as preferable production methods.

First, according to the first method, the general formula [In formula, X < ¹ > -X < ⁴ > is the same as the above. ] An alkaline aqueous solution of tetrahalogenobisphenol A (tetrabromobisphenol A, tetrachlorobisphenol A, tetrafluorobisphenol A, etc.) (sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, etc.) represented by Alkaline aqueous solution of bisphenol A (BPA) represented by [In formula, X < ⁵ > -X < ⁷ > is the same as the above. ] An alkaline aqueous solution of trihalogenophenol (tribromophenol, trichlorophenol, trifluorophenol, etc.) represented by And agitated at a predetermined ratio, and phosgene was blown into the mixture to promote interfacial polycondensation. Since the reaction system generates heat at this time, it is preferable to cool with water or ice, and as the reaction progresses, the reaction system shifts to the acidic side.Therefore, add an alkali while measuring with a pH meter to adjust the pH. Is preferably maintained at 10 or more.

In addition, a part (50 mol% or less) of the trihalogenophenol may be changed to a monohydric phenol such as p-tert-butylphenol or phenol, and may be used in combination.

In the polycondensation reaction, the tetrahalogenobisphenol A of formula (A ') constitutes the repeating unit (I) in the resulting polycarbonate, and the bisphenol A of formula (B') constitutes the repeating unit (II). Therefore, the charging ratio of the above tetrahalogenobisphenol A and bisphenol A should be appropriately determined according to the mole fraction of repeating units (I) and (II) of the polycarbonate to be produced or the proportion of halogen atoms to be contained. Become. On the other hand, the introduced amounts of trihalogenophenol and phosgene determine the degree of polymerization of each of the repeating units (I) and (II), and further the degree of polymerization of the entire polycarbonate, and thus the molecular weight. Therefore, the amount to be introduced may be an amount according to the purpose. Further, in blowing phosgene, the blowing amount per time is appropriately adjusted so that the total blowing amount at the end of the reaction is the supply amount required for the reaction.

The reaction product thus obtained is poured into a large amount of a precipitating agent such as methanol to precipitate the polycarbonate of the present invention.

In the above reaction, instead of phosgene, various carbonic acid ester forming derivatives such as bromophosgene, diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate, etc. It is also possible to use.

Next, according to the second method, a polycarbonate oligomer is previously synthesized with bisphenol A and phosgene, and an alkali aqueous solution of tetrahalogenobisphenol A and an alkali aqueous solution of trihalogenophenol and this oligomer can be dissolved in this oligomer. Preliminary polymerization is carried out by mixing and stirring a solvent such as methylene chloride and a catalyst such as triethylamine and trimethylbenzylammonium chloride in a predetermined amount ratio, followed by preliminarily polymerizing an alkaline aqueous solution of bisphenol A and optionally p-tert-butylphenol. In addition, the polycondensation reaction proceeds. The polycarbonate of the present invention is deposited by pouring the obtained reaction product into a large amount of a precipitating agent (methanol or the like).

The polycarbonate of the present invention can be efficiently produced by the above-mentioned method. As another method, a polycarbonate oligomer is previously synthesized with tetrahalogenobisphenol A and phosgene, and bisphenol A and trihalogenophenol are appropriately added to this oligomer. Of reacting in the presence of various solvents, alkaline aqueous solutions, catalysts, etc., suitable for tetrahalogenobisphenol A (or bisphenol A), trihalogenophenol to polycarbonate oligomer synthesized from bisphenol A (or tetrahalogenobisphenol A) and phosgene Reaction in the presence of various solvents, alkaline aqueous solutions, catalysts, etc., and blowing phosgene in the process, as well as synthesizing an oligomer from bisphenol A and phosgene, Rogge Roh leave synthesized oligomer from bisphenol A and phosgene, these two kinds of oligomers between trihalogenophenol and a suitable solvent,
In the method of reacting in the presence of an aqueous alkaline solution, a catalyst or the like or the above-mentioned method, it is effective to employ a multi-step polymerization method in which the polymerization is divided into two steps or more.

The polycarbonate of the present invention can be obtained by any of these methods.

The polycarbonate of the present invention has a viscosity average molecular weight of 10,000 to 50,000, preferably 13,000 to 50,000 as described above. To adjust the viscosity average molecular weight to this range, trihalogenophenol mainly used as a molecular weight modifier is used. This can be done by selecting the usage amount of. Usually, it is 0 for diphenols that make up the main chain.
It is used in a ratio of 01 to 0.1 times.

Further, when a catalyst such as BPA, an alkaline aqueous solution and triethylamine is added to the polycarbonate oligomer to produce a polycarbonate by interfacial polycondensation,
The amount of the catalyst used is usually 0.
It is 0005 to 0.03 (mol / mol).

Further, when a catalyst such as BPA, an alkaline aqueous solution and triethylamine is added to the polycarbonate oligomer to produce a polycarbonate by interfacial polycondensation,
The amount of caustic alkali used is usually 0.1 to 5.0 (mol / mol) of caustic / diphenols.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Synthesis Example (Synthesis of Polycarbonate Oligomer of Bisphenol A) 91 g of bisphenol A (BPA), 330 ml of methylene chloride and 2.
560 ml of 0N aqueous sodium hydroxide solution was added and stirred, and phosgene was blown into this for 70 minutes while cooling with water. When the obtained reaction solution was allowed to stand at room temperature, a methylene chloride solution of an oligomer was separated and formed in the lower layer. This oligomer solution had an oligomer concentration of 320 g /, a number average molecular weight of 850, and a chloroformate group concentration of 0.7 mol /.

Example 1 An aqueous sodium hydroxide solution of polycarbonate oligomer 10, tetrabromobisphenol A (TBA) and tribromophenol (TBP) synthesized in the above Synthesis Example in a container with an internal volume of 50 and a stirrer [TBA250
g (0.460 mol), TBP 150 g (0.453 mol)
g), 78.6 g (1.96 mol) of sodium hydroxide, 1.35] 1.8 of water and 1.8 ml (0.013 mol) of triethylamine were added, and the mixture was stirred at 500 rpm. After 60 minutes, an aqueous solution of BPA in sodium hydroxide [B
PA457 g (2.00 mol), sodium hydroxide 26
7 g (6.68 mol), water 3.42] 3.9 and methylene chloride 6.1 were added and stirred.

After stirring for 60 minutes, the resulting reaction product was separated into an aqueous phase and a methylene chloride phase containing the produced copolymer.

The methylene chloride phase was washed with water, an acid (0.1N hydrochloric acid), and water in this order. Methylene chloride was removed from this methylene chloride phase at 40 ° C. under reduced pressure to obtain a white powder (copolymer).
Got After drying at 120 ° C. for a whole day and night, it was melted by an extruder and pelletized. The glass transition temperature (Tg) of this pellet was measured and found to be 152.6 ° C. The viscosity average molecular weight was 23,900. When the molecular weight distribution was measured by gel permeation chromatography, it showed a distribution having a single peak at the above value.
The content of TBA [repeating unit (I)] in the main chain of this copolymer was 3.1 mol% as determined by NMR.

Next, the pellets were heated in an injection molding machine at a temperature of 300 ° C.
Injection molding was performed at an injection pressure of 55 kg / cm ² to obtain a test piece. The Izod impact strength and flame retardancy of this test piece were measured. Also, the flow value of the pellet was measured by a falling flow tester.

The bromine content of the obtained pellets was measured to be 6.4.
% By weight. The measurement of the bromine content was carried out by subjecting the sample to alkali decomposition and then analyzing by the Horhard method.

Further, the molding heat stability test was conducted as follows. The pellet is retained by injection molding at 300 ° C. for 30 minutes, and then a test piece is prepared. The yellowness index (YI) of the obtained test piece is measured with a transmission photometer.

The results are shown in Table 1.

Examples 2 and 3 The same operation as in Example 1 was performed except that the aqueous sodium hydroxide solution of TBA and TBP was changed as shown in Table 1. The results are shown in Table 2.

Example 4 The same operation as in Example 1 was carried out except that the sodium hydroxide aqueous solution of TBA and TBP was changed as shown in Table 1. The results are shown in Table 2.

Example 5 The same operation as in Example 1 was performed except that the aqueous sodium hydroxide solution of TBA and TBP was changed as shown in Table 1. The results are shown in Table 2.

Comparative Examples 1 and 2 Example 1 was repeated except that the amount of TBA was changed and p-tert-butylphenol (PTBP) was used instead of TBP as shown in Table 1 for the aqueous sodium hydroxide solution of TBA and TBP. The same operation was performed. The results are shown in Table 2.

Comparative Example 3 The same operation as in Example 1 was performed except that the sodium hydroxide aqueous solution of TBA and TBP was changed as shown in Table 1. The results are shown in Table 2.

Comparative Examples 4 and 5 The same as Example 1 except that the amount of TBA was changed and pentabromophenol (PBP) was used instead of TBP as shown in Table 1 for the aqueous sodium hydroxide solution of TBA and TBP. The operation was performed. The results are shown in Table 2.

[Effects of the Invention] As described above, the polycarbonate of the present invention is excellent in flame retardancy, sufficiently high in impact resistance, and excellent in molding heat stability. Particularly, as flame retardancy, UL-094 1/16 inch (thickness) is V-0.
As for impact resistance, Izod impact strength is 40 kg / c.
m / cm or more, 300 ° C as molding heat stability,
YI after retention of 30 minutes is 20 or less.

Therefore, the polycarbonate of the present invention can be widely and effectively used in various industrial materials such as home appliances, OA equipment, building materials, and sheets.

[Brief description of drawings]

FIG. 1 is an infrared absorption (IR) spectrum of the copolymer obtained in Example 1 by a deposition thin film method, and FIG. 2 is a nuclear magnetic resonance (NMR) spectrum (solvent: deuterated chloroform) of this copolymer.

Claims (1)

[Claims] 1. A general formula [In formula, X < ¹ > -X < ⁴ > shows a halogen atom. ] The repeating unit (I) represented by In addition to having the repeating unit (II) represented by ^Wherein, X 5 to X ⁷ is a halogen atom. ] The trihalogenophenoxy group represented by is bonded, the viscosity average molecular weight thereof is 10,000 to 50,000, and the content of the repeating unit (I) in the main chain is 1 to 10 mol%. Polycarbonate.