JP2000169696A - Flame-retarded polycarbonate resin composition excellent in thermal stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retarded polycarbonate resin composition capable of not only stably manifesting excellent flame retardance but also improved in thermal stability by regulating the sodium molar fraction in a nonhalogen- based aromatic sulfonic acid and the sodium content distributed in the polycarbonate resin. SOLUTION: This flame-retarded polycarbonate resin composition contains 0.001-0.05 pt.wt. of a value represented by the following formula-2 and expressed in terms of sodium in a resin composition obtained by compounding a polycarbonate resin with a sodium nonhalogen-based aromatic sulfonate having 0.075-0.13 sodium molar fraction represented by formula-1. formula-1: the sodium molar fraction = atomic weight of sodium/molecular weight of the sodium nonhalogen-based aromatic sulfonate. formula-2: the value expressed in terms of sodium = amount (pts.wt.) of the compounded sodium nonhalogen-based aromatic sulfonate based on 100 pts.wt. of the polycarbonate resin × sodium molar fraction represented by formula-1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flame-retardant polycarbonate resin composition. More specifically, polycarbonate resin has excellent mechanical, heat and electrical properties, imparts flame retardancy without impairing heat, and has excellent thermal stability with extremely low molecular weight reduction due to stagnation. And a flame-retardant polycarbonate resin composition.

[0002]

2. Description of the Related Art Polycarbonate resins have been used in a wide range of fields as plastic materials having excellent impact resistance, heat resistance, and electrical properties, and also having self-extinguishing properties.
However, the flammability of the polycarbonate resin differs depending on the molecular weight, and the burning time tends to increase as the molecular weight increases.

[0003] Therefore, the polycarbonate resin alone has a thickness of 1.6 in a method based on the combustion test (UL94) of Underwriters Laboratories (UL).
In order to satisfy V-2 in mm, a material having a relatively low molecular weight had to be used. If a low molecular weight polycarbonate resin is used, there are problems such as lack of mechanical properties depending on the use of the molded article, and a polycarbonate resin having a high molecular weight and excellent flame retardancy has been demanded.

Various methods have been attempted to impart flame retardancy to polycarbonate resins, and flame retardants and flame retardant auxiliaries such as halogen-based, phosphorus-based, silicone-based, inorganic-based, and organic metal-salt-based agents have been used. Attempts have been made to satisfy the required flame retardancy level by the addition.

[0005] Some organic metal salt-based flame retardants exhibit a flame retardant effect when added in a small amount, and are used as useful flame retardants. Japanese Patent Publication No. 57-33302 discloses a method in which a sulfonic acid metal salt-substituted compound of an aromatic carboxylic acid or a carboxylic acid ester is added to a polycarbonate resin, and Japanese Patent Publication No. 57-43100 discloses a polycarbonate resin containing an aromatic sulfonic acid metal salt. There has been proposed a method of making the composition flame-retardant by adding a compound.

[0006]

However, there is a considerable difference in the flammability depending on the kind of the metal aromatic sulfonic acid salt compound, and the halogenated aromatic metal sulfonic acid salt has good flame retardancy. There were some, but none of the metal salts of non-halogenated aromatic sulfonic acids showed sufficient flame retardancy. Further, when the amount of these aromatic sulfonic acid metal salts is large, the thermal stability may be inferior when the amount of addition is large.In injection molding, the molding temperature may be increased or the molding cycle may be increased due to factors such as the product shape and the injection molding function. In a situation where it is necessary to take a long time, there is a problem that appearance defects such as discoloration and silver streaks of a molded product occur.

[0007]

DISCLOSURE OF THE INVENTION In view of the above problems, the present inventors have intensively studied the improvement of flame retardancy and thermal stability in a blend of a polycarbonate resin and a metal salt of a non-halogenated aromatic sulfonic acid. As a result, by combining the polycarbonate resin with a non-halogenated aromatic sodium sulfonate having a sodium mole fraction adjusted and also adjusting the total sodium content of the resin composition, surprisingly, the combustibility due to the molecular weight of the polycarbonate resin Of the polycarbonate resin, and found that the decrease in the molecular weight of the polycarbonate resin due to stagnation was extremely small, and completed the present invention. According to the present invention, in the UL94 combustion test, the flame retardancy of V-2 can be stably exhibited at a thickness of 1.6 mm, and the thermal stability accompanying the molding process is excellent.

That is, the present invention provides a polycarbonate resin and a non-halogenated aromatic sodium sulfonate represented by the following formula-1 (hereinafter referred to as formula-1) having a sodium mole fraction of 0.075 to 0.13. In the resin composition to be blended, the sodium-converted value represented by the following formula-2 (hereinafter, referred to as formula-2) is 0.001 to 0.05 parts by weight, which is excellent in heat stability. A flame-retardant polycarbonate resin composition is provided. (Formula-1) Sodium mole fraction = Atomic weight of sodium / Molecular weight of non-halogenated aromatic sodium sulfonate (Formula-2) Sodium conversion value = Blend of non-halogenated aromatic sodium sulfonate per 100 parts by weight of polycarbonate resin Amount (parts by weight) × Sodium mole fraction of formula-1 Hereinafter, the resin composition of the present invention will be described in detail.

The polycarbonate resin used in the present invention is a resin obtained by a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, or a transesterification method in which a dihydroxydiaryl compound is reacted with a carbonate such as diphenyl carbonate. And 2,2-bis (4-
(Hydroxyphenyl) propane (bisphenol A).

As the dihydroxydiaryl compound, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl), in addition to bisphenol A,
Butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4 -Hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,
Bis (hydroxyaryl) alkanes such as 5-dichlorophenyl) propane, bis (hydroxyaryl) such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane Cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-
Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether; dihydroxy diaryl sulfides such as 4,4'-dihydroxy diphenyl sulfide; 4,4'-dihydroxy diphenyl sulphoxide; 4,4'-dihydroxy-3,3 Dihydroxydiarylsulfoxides such as'-dimethyldiphenylsulfoxide; and dihydroxydiarylsulfones such as 4,4'-dihydroxydiphenylsulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone.

These are used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl and the like may be used as a mixture.

Further, the above-mentioned dihydroxyaryl compound and a phenol compound having three or more valences as shown below may be mixed and used.

The phenols having 3 or more valences include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, and 2,4,6-dimethyl-2,4,6-triphenol. -(4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4,4-
(4,4'-dihydroxydiphenyl) -cyclohexyl] -propane.

The viscosity average molecular weight of the polycarbonate resin is usually 10,000 or more and 100,000 or less, preferably 15 to 100,000.
000 or more and 35,000 or less. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as required.

The non-halogenated aromatic sodium sulfonate used in the present invention has a sodium mole fraction of 0.0
75 to 0.13. In this calculation, the atomic weight of each element is calculated based on the atomic weight table of the International Union of Pure and Applied Chemistry (IUPAC) (1995). For example,
1.0080 for hydrogen, carbon, oxygen, nitrogen, sulfur,
12.0107 and 15.9 for sodium respectively
994, 14.0067, 32.0666, 22.98
98.

If the sodium mole fraction of the non-halogenated sodium aromatic sulfonate is less than 0.075, the proportion of sodium contained in the compound becomes too small, and the flame retardancy is poor, which is not preferable. On the other hand, if the sodium mole fraction exceeds 0.13, the flame retardancy is inferior, which is not preferable. More preferably, it is in the range of 0.077 to 0.12.

The non-halogenated aromatic sodium sulfonate used in the present invention includes sodium p-toluenesulfonate, sodium p-styrenesulfonate,
Sodium naphthalenesulfonate; sodium dimethyl-5-sulfonate isophthalate; and the like, and one or more of these can be used in combination.

Preferably, the compounding amount of the non-halogenated sodium aromatic sulfonate is preferably 1% of polycarbonate resin.
It is in the range of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.4 parts by weight, per 100 parts by weight.

The non-halogenated aromatic sodium sulfonate has a sodium conversion value of 0.001 to 0.05 represented by the formula-2 per 100 parts by weight of the polycarbonate resin.
It is an indispensable condition that the amount is by weight. The amount of sodium blended in the polycarbonate resin is a factor for developing desirable flame retardancy. Sodium conversion value is 0.001
If the amount is less than parts by weight, the proportion of sodium contained in the polycarbonate resin is too small, and the flame retardancy is poor, which is not preferable. On the other hand, if the sodium-converted value exceeds 0.05 parts by weight, sufficient flame retardancy cannot be obtained, and further, the decrease in the molecular weight of the retained polycarbonate is undesirably large. More preferably, 0.002
０．０0.04 parts by weight.

According to the present invention, by adjusting the sodium-converted value of the formula (2) to a specific range, not only can the polycarbonate resin be imparted with good flame retardancy, but also the decrease in the molecular weight of the polycarbonate resin after stagnation can be prevented. Less and improved thermal stability. Usually, the molding temperature of the polycarbonate resin is 280 to 300 ° C., and the molding cycle is 10 to 40 seconds. In contrast, in the case of the polycarbonate resin composition of the present invention, at a very high molding temperature of 340 ° C.,
Further, even under severe conditions with a molding cycle of 120 seconds, the reduction rate of the molecular weight is 5% or less, and the composition has good thermal stability.

The polycarbonate resin composition of the present invention comprises:
Other known flame retardants, for example, sulfonic acid metal salt compounds, halogen-based flame retardants, silicone-based flame retardants, and phosphorus-based flame retardants may be mixed.

Examples of the sulfonic acid metal salt compound include a metal salt of diphenylsulfone-3-sulfonic acid, a metal salt of diphenylsulfone-3,3'-disulfonic acid and a metal salt of diphenylsulfone-3,4'-disulfonic acid. Alkali metal salts of aromatic sulfonic acids, metal salts of saccharin, metal salts of N- (p-tolylsulfonyl) -p-toluenesulfonimide, metal salts of N- (N'-benzylaminocarbonyl) sulfanylimide and N- Aromatic sulfonamide metal salts such as (phenylcarboxyl) -sulfanylimide metal salts, sodium and potassium salts of perfluoromethanesulfonic acid, sodium and potassium salts of perfluoroethanesulfonic acid, sodium and potassium salts of perfluoropropanesulfonic acid Salt, perfume Sodium and potassium salts of lobutanesulfonic acid, sodium and potassium salts of perfluorohexanesulfonic acid, alkali metal salts of perfluoroalkanesulfonic acid such as sodium and potassium salts of perfluorooctanesulfonic acid, 2,5-dichlorobenzenesulfonic acid And alkali metal salts of halogenated aromatic sulfonic acids such as sodium and potassium salts, and sodium and potassium salts of 2,4,5-trichlorobenzenesulfonic acid.

As halogen-based flame retardants, brominated bisphenol A derivatives, polybromo-substituted aromatic analogs and the like are used. As silicone-based flame retardants, polyorganosiloxanes,
Polycarbonate-polyorganosiloxane copolymers and the like, and phosphorus-based flame retardants include phosphate esters and the like.

Further, as long as the effects of the present invention are not impaired,
Various types of fibril-forming polymers (eg, tetrafluoroethylene / hexafluoropropylene copolymer, partially fluorinated polymers as shown in US Pat. No. 4,379,910, polycarbonates prepared from fluorinated diphenols, etc.), Stabilizers (eg, metal hydrogen sulfate such as sodium hydrogen sulfate, potassium hydrogen sulfate, lithium hydrogen sulfate and metal sulfate such as aluminum sulfate), antioxidants, coloring agents, fluorescent whitening agents,
Fillers (eg, glass fibers, glass beads, glass flakes, carbon fibers, talc powder, clay powder, mica, potassium titanate whiskers, wollastonite powder, silica powder, etc.), release agents, softeners, antistatic agents , Etc., impact modifiers (for example, acrylic elastomer, polyester elastomer, core-shell type methyl methacrylate / butadiene / styrene copolymer, methyl methacrylate / acrylonitrile / styrene copolymer, ethylene / propylene rubber, Ethylene-propylene-diene rubber, etc., other polymers (for example, polyester such as polyethylene terephthalate, polybutylene terephthalate, polystyrene, high impact polystyrene, acrylonitrile / styrene copolymer and modified acrylic rubber, acrylic Nitrile-butadiene-styrene copolymer, acrylonitrile-ethylene - propylene - diene rubber (EPDM), styrene copolymers such as styrene-based polymers, polypropylene, or the like olefinic polymers such as polyethylene) may be incorporated.

The method of mixing the various components in the polycarbonate resin composition of the present invention is not particularly limited, and includes a known mixer such as a tumbler, a ribbon blender or the like, and a melt kneading using an extruder.

The method for molding the polycarbonate resin composition of the present invention is not particularly limited, and a known injection molding method, injection / compression molding method, or the like can be used.

[0027]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. The “parts” are based on weight. The evaluation method of each polymer is as follows:

Granulation The resin melt-kneaded in the extruder was visually evaluated for its appearance when it emerged in a strand form from the tip of the extruder.

Formability Test pieces were prepared from the pellets obtained by granulation according to the following injection conditions, and the appearance of the test pieces was visually checked. The test piece was 80 mm long and 50 mm wide and had a thickness of 1.
A two-stage molded product of 6 mm and 3.2 mm was used. Molding temperature: 340 ° C Mold temperature: 100 ° C Molding cycle: 30 seconds

-Retention heat stability test (Molding conditions) The pellets obtained by granulation were prepared into test pieces similar to the above under the following injection conditions. Molding temperature: 340 ° C Mold temperature: 100 ° C Molding cycle: 120 seconds (Molecular weight reduction rate) Twelve test pieces were prepared under the above molding conditions, using the molecular weight of the pellets produced by granulation as a standard value. The molecular weight of the twelfth test piece was measured, and the molecular weight reduction rate was calculated by the following formula-3. Formula-3 Molecular weight reduction rate (%) = (molecular weight of granulated pellet−molecular weight of twelfth test piece) × 100 / (molecular weight of granulated pellet)

Measurement of molecular weight A solution having a concentration of 0.5 g / l was prepared using methylene chloride as a solvent, and the solution was heated to 20 ° C. using a Cannon-Fenske viscometer.
Was measured.

Flammability test (Preparation of test specimen for UL test) Pellets obtained by granulation were injection molded at a molding temperature of 300 ° C.
A test piece having a thickness of 25 mm, a width of 13 mm, and a thickness of 1.6 mm was prepared. (Evaluation of flammability) The test piece was left in a constant temperature room at a temperature of 23 ° C and a humidity of 50% for 48 hours, and was subjected to UL9 specified by UL.
4 tests (flammability test of plastic materials for equipment parts)
The flame retardancy was evaluated in accordance with. UL94V refers to a test piece of a predetermined size held vertically, in which a burner flame is applied to a test piece.
This is a method of evaluating the flame retardancy from the after-flame time and drip property after indirectly burning for 0 seconds. In order to have the flame retardancy of V-2, it is necessary to satisfy the following criteria. The afterflame time shown above is the length of time that the test piece continues to burn flaming after the ignition source is moved away, and the ignition of cotton by drip is about 300 mm below the lower end of the test piece. It is determined by whether or not a certain marking cotton is ignited by a drip from the test piece. If at least one of the five samples does not satisfy the above criterion, it is determined that V-2 is not satisfied, and NR (not rate) is not satisfied.
d).

Example 1 Production of Resin Pellets A mixture of 100 parts of a polycarbonate resin and 0.02 parts of sodium p-toluenesulfonate (A-1) having a sodium mole fraction of 0.118 was added to a twin screw extruder. Using a machine (KTX-37, manufactured by Kobe Steel, shaft diameter = 37 mm), the mixture was melted and mixed at a temperature of 300 ° C. The melt-mixed resin was extruded in a strand shape, and quenched in a water tank was processed into strand pellets using a pelletizer. At this time, no discoloration or decomposition was observed in the state of the strand, and the strand could be granulated without any problem. The viscosity average molecular weight of the obtained pellet was 26,200, and the sodium equivalent was 0.0024.

Evaluation of moldability and retention heat stability Next, the resin pellets dried for 3 hours at 125 ° C. in a hot air circulation shelf oven were injected into an injection molding machine (J100E-C5 clamping force by Nippon Steel Works = 100 tons), and the molding was continuously performed for 30 seconds under the temperature condition of 340 ° C. and the appearance of the obtained molded product was confirmed. Molded. Further, the molding temperature was the same, the molding cycle was lengthened to 120 seconds, the retention molding was performed, and the viscosity average molecular weight of the molded product taken out at the twelfth was measured to be 25500, and the molecular weight reduction rate was 2.
It was 7%, which was very good because it was 5% or less.

Preparation of UL Test Specimen and Evaluation of Combustion Test Resin pellets adjusted under the same drying conditions as described above were subjected to injection molding machine (J100E-C5 manufactured by Nippon Steel Works, clamping force = 100 ton) at 300 ° C. A test piece was prepared according to the temperature, and was placed in a constant temperature room at a temperature of 23 ° C and a humidity of 50%.
When a combustion test was performed on the sample left for 8 hours,
V-2. Table 1 summarizes the above results.

(Examples 2 to 3) The same operation as in Example 1 was carried out except that the amount of the flame retardant A-1 was changed as shown in Table 1, and granulation, molding and evaluation were performed. The results are shown in Table 1.

(Comparative Examples 1 to 3) The same operation as in Example 1 was performed except that the amount of the flame retardant A-1 was changed as shown in Table 1, and granulation, molding and evaluation were performed. The results are shown in Table 1.

[0038]

[Table 1]

As shown in Table 1, those having a sodium conversion value calculated by the formula (2) in the range of 0.001 to 0.05 parts (Examples 1 to 3) had a decrease in molecular weight of 5%. In the test of UL94 which is the following and is an index of flame retardancy,
A rating of -2 was indicated. Also. Granulation properties and moldability were also good. On the other hand, in the sample of Comparative Example 1 in which the sodium conversion value is less than 0.001 part, UL which is an index of flame retardancy is used.
In the test of 94, there was a test piece that exceeded 30 seconds to extinguish the fire.
2 cannot be satisfied (NR; not rated),
It was inferior in flame retardancy. In addition, sodium conversion value is 0.0
In the samples of Comparative Examples 2 and 3 exceeding 5 parts, the molecular weight reduction rate exceeded 5%, and the flame retardancy was also NR.
Note that the higher the sodium conversion value, the higher the molecular weight reduction rate and the longer the burning time of UL94. (See Comparative Examples 2 and 3.) In addition, in Comparative Example 3, a large amount of silver streaks occurred in the molded product in the moldability test.

(Examples 4 to 8) The same operations as in Example 1 were carried out except that the type and the amount of the flame retardant were changed as shown in Table 2, and granulation, molding and evaluation were performed. The results are shown in Table 2. The flame retardants used are as follows: Example 4: sodium dimethyl-5-sulfonate isophthalate (A-2) Sodium mole fraction = 0.078 Example 5: sodium p-styrenesulfonate (A-
3) Sodium mole fraction = 0.112 Example 6: Sodium 1-naphthalenesulfonate (A-
4) Sodium mole fraction = 0.100 Example 7: Sodium benzenesulfonate (A-5) Sodium mole fraction = 0.128 Example 8: Sodium p-toluenesulfonate (A-
1) Sodium 1-naphthalenesulfonate (A-4) Sodium mole fraction = 0.118 (A-1) Sodium mole fraction = 0.100 (A-4)

(Comparative Examples 4 to 7) The same operations as in Example 1 were carried out, except that the type and amount of the flame retardant were changed as shown in Table 2, and granulation, molding and evaluation were performed. The results are shown in Table 2. The flame retardants used are as follows: Comparative Example 4: Sodium n-dodecylbenzenesulfonate (A-6) sodium mole fraction = 0.066 Comparative Example 5: Sodium mole of sodium allyl sulfonate (A-7) Fraction = 0.160 Comparative Example 6: Sodium methacrylsulfonate (A-8) Sodium mole fraction = 0.146 Comparative Example 7: Sodium m-benzenedisulfonate (A-
9) Sodium mole fraction = 0.163

[0042]

[Table 2]

As shown in Table 2, a non-halogenated aromatic sodium sulfonate having a sodium mole fraction of 0.075 to 0.13 was used, and the sodium conversion value was 0.1%.
In all the samples (Examples 4 to 7) adjusted to 001 to 0.05 parts, the molecular weight reduction rate was 5% or less, and the flammability test result of UL94 showed V-2 flame retardancy. . Further, in the sample (Example 8) in which two kinds of non-halogenated sodium aromatic sulfonates were used in combination, the same results were obtained as long as the sodium mole fraction and the sodium conversion value were within the specified ranges. On the other hand, even in the case where the sodium conversion value was within the specified range, a sample in which the sodium mole fraction was outside the specified range (Comparative Examples 4 to 7) did not yield favorable results. For example, in the samples of Comparative Example 4 in which the sodium mole fraction was smaller than the specified value and Comparative Example 7 in which the sodium mole fraction was larger than the specified value, the flame retardancy was NR although the molecular weight reduction rate was 5% or less. In Comparative Examples 5 and 6 having no phenyl group and having a sodium mole fraction larger than the specified value,
A decomposition reaction occurred during granulation, and pelletization was impossible.

[0044]

According to the present invention, excellent flame retardancy is stably exhibited by adjusting the sodium mole fraction in the non-halogenated aromatic sulfonic acid and the amount of sodium distributed in the polycarbonate resin. It is possible to provide a flame-retardant polycarbonate resin composition which has not only reduced heat resistance but also improved thermal stability.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 26, 1999 (1999.4.2
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

As shown in Table 1, those having a sodium conversion value calculated by the formula (2) in the range of 0.001 to 0.05 parts (Examples 1 to 3) had a decrease in molecular weight of 5%. In the test of UL94 which is the following and is an index of flame retardancy,
A rating of -2 was indicated. In addition , granulation properties and moldability were also good. On the other hand, in the sample of Comparative Example 1 in which the sodium conversion value is less than 0.001 part, UL which is an index of flame retardancy is used.
In the test of 94, there was a test piece that exceeded 30 seconds to extinguish the fire.
2 cannot be satisfied (NR; not rated),
It was inferior in flame retardancy. In addition, sodium conversion value is 0.0
In the samples of Comparative Examples 2 and 3 exceeding 5 parts, the molecular weight reduction rate exceeded 5%, and the flame retardancy was also NR.
Note that the higher the sodium conversion value, the higher the molecular weight reduction rate and the longer the burning time of UL94. (See Comparative Examples 2 and 3.) In addition, in Comparative Example 3, a large amount of silver streaks occurred in the molded product in the moldability test.

[Procedure amendment]

[Submission Date] June 25, 1999 (1999.6.2
5)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction contents]

[0042]

[Table 2]

Claims (4)

[Claims] 1. A resin composition comprising a polycarbonate resin and a non-halogenated aromatic sodium sulfonate having a sodium mole fraction of 0.075 to 0.13 represented by the following formula-1: 2. A flame-retardant polycarbonate resin composition having excellent thermal stability, wherein the sodium-equivalent value shown in 2 is 0.001 to 0.05 part by weight. (Formula-1) Sodium mole fraction = Atomic weight of sodium / Molecular weight of non-halogenated aromatic sodium sulfonate (Formula-2) Sodium conversion value = Blend of non-halogenated aromatic sodium sulfonate per 100 parts by weight of polycarbonate resin Amount (parts by weight) × Sodium mole fraction of formula-1 2. The flame-retardant polycarbonate resin composition according to claim 1, wherein the sodium mole fraction of the non-halogenated aromatic sodium sulfonate is 0.077 to 0.12. 3. The sodium-converted value represented by the formula-2 is 0.00
The flame-retardant polycarbonate resin composition having excellent heat stability according to claim 1, which is used in an amount of 2 to 0.04 parts by weight. 4. The non-halogenated aromatic sodium sulfonate is selected from sodium p-toluenesulfonate, sodium p-styrenesulfonate, sodium 1-naphthalenesulfonate and sodium dimethyl-5-sulfonate isophthalate. The flame-retardant polycarbonate resin composition having excellent thermal stability according to claim 1, wherein the composition is one or more kinds.