KR20150067457A - Flame-retardant polyethyleneterephthalate resin composition having excellent impact resistance and molded article thereof - Google Patents

Abstract

The present invention relates to a flame-retardant polyethylene terephthalate resin composition and a molded article thereof and, more specifically, to a thermoplastic copolymer resin composition and a molded article thereof, wherein the composition comprises a polyethylene terephthalate resin and a polysiloxane-branched polycarbonate copolymer resin, thus has excellent flame retardancy with using neither a halogen-based flame retardant agent nor a phosphor-based flame retardant agent, or using a minimal amount of the same, and has remarkably improved impact resistance without using an additional impact modifier.

Description

TECHNICAL FIELD [0001] The present invention relates to a flame retardant polyethylene terephthalate resin composition having remarkably improved impact resistance and a molded article thereof,

More particularly, the present invention relates to a flame retardant polyethylene terephthalate resin composition and a molded article thereof, and more particularly, to a flame retardant polyethylene terephthalate resin composition containing a polyethylene terephthalate resin and a polysiloxane-branched polycarbonate copolymer resin, Which is excellent in flame retardancy and is remarkably improved in impact resistance without using an additional impact modifier, and a molded article thereof.

The polycarbonate / vinyl copolymer resin composition is widely used in automobile parts, computer housings or other office equipment housings because it exhibits improved workability while maintaining excellent impact resistance, heat resistance and mechanical strength. Flame retardancy is also required due to its characteristics.

In general, the flame retarding system for PET and PC resin alloys, in which a polycarbonate (PC) resin having self-extinguishing properties is incorporated in a polyethylene terephthalate (PET) resin, includes a phenoxy compound of tetrabisphenol A A fluorinated olefin based resin is used as a phenoxy-terminated carbonate oligomer of Tetrabromobisphenol A or triphenylphosphate as a phosphorus compound and an anti-dripping agent.

U.S. Patent No. 4,692,488 and U.S. Patent No. 5,061,745 disclose a flame retardant resin composition prepared by mixing a diphenol-based aromatic polycarbonate resin with a monomer-type phosphate ester flame retardant.

However, halogen-based flame retardants and phosphorus-based flame retardants used in such resin compositions are required to minimize their use as harmful components to the human body. Further, the use of such a low-molecular-weight flame retardant agent has a problem in that the physical properties (for example, impact strength, etc.) of the article are lowered and the so-called "plate-out" phenomenon occurs in which the added flame retardant agent migrates to the surface of the molded article It is also said.

Accordingly, there is a demand for development of a thermoplastic resin composition which can improve the flame retardancy while minimizing the use of the halogen-based flame retardant and phosphorus flame retardant, and at the same time exhibiting excellent impact resistance without using a separate impact modifier .

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a flame-retardant flame retardant composition which is excellent in flame retardancy, A thermoplastic resin composition and a molded article thereof are provided.

(A) a polysiloxane-branched polycarbonate block copolymer resin comprising a hydroxy-terminated polysiloxane represented by the following formula (1) and a branched polycarbonate block as repeating units, and (B) a poly A flame retardant thermoplastic resin composition comprising a phthalate resin is provided:

[Chemical Formula 1]

In Formula 1,

R ₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an aryl group,

R ₂ independently represents a hydrocarbon group or a hydroxy group having 1 to 13 carbon atoms,

R ₃ independently represents an alkylene group having 2 to 8 carbon atoms,

m is independently an integer of 0 to 4,

n independently represents an integer of 1 to 200,

A represents a structure represented by the following formula (2) or (3)

(2)

In Formula 2,

Y is a linear or branched aliphatic group having 1 to 20 carbon atoms, a cycloalkylene group, or a substituted or unsubstituted alkylene group substituted with a halogen atom, an alkyl group, an alkoxy group, an aryl group or a carboxyl group, A monocyclic or polycyclic arylene group having 6 to 30 carbon atoms,

(3)

In Formula 3,

R ₄ represents an aromatic or aromatic / aliphatic mixed hydrocarbon group having 6 to 30 carbon atoms or an aliphatic hydrocarbon group having 1 to 20 carbon atoms.

According to another aspect of the present invention, there is provided a process for preparing (1) preparing a branched polycarbonate oligomer; (2) copolymerizing the branched polycarbonate oligomer prepared in the step (1) and the hydroxy-terminated polysiloxane of the formula (1) to prepare a polysiloxane-branched polycarbonate block copolymer resin; And (3) melt-mixing the polysiloxane-branched polycarbonate block copolymer resin prepared in the step (2) and a polyethylene terephthalate resin.

According to another aspect of the present invention, there is provided a molded article of the flame retardant thermoplastic resin composition.

The flame retardant thermoplastic resin composition according to the present invention can exhibit excellent flame retardancy while minimizing the use or use of a halogen-based flame retardant and a phosphorus-based flame retardant, and can exhibit remarkably improved impact resistance without using a separate impact modifier, It can be useful for producing products such as office equipment and housings of electrical and electronic products that require impact resistance.

As used herein, the term "reaction product" means a material in which two or more reactants are formed by reaction.

The letter "R" used to represent hydrogen, a halogen atom and / or a hydrocarbon group in the formulas described in the present specification has a subscript indicated by a numeral, but the letter "R" But is not limited thereto. The "R" represents, independently of each other, hydrogen, a halogen atom and / or a hydrocarbon group. For example, the "R" s may represent the same hydrocarbon group or may represent other hydrocarbon groups, irrespective of whether two or more "R" have the same or different numbers of subscripts.

Hereinafter, the present invention will be described in more detail.

(A) Polysiloxane - Ground  Polycarbonate block copolymer resin

The polysiloxane-branched polycarbonate block copolymer resin contained in the flame-retardant thermoplastic resin composition according to the present invention comprises, as repeating units, a hydroxy-terminated polysiloxane having the following formula (1) and a branched polycarbonate block:

[Chemical Formula 1]

In Formula 1,

R ₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an aryl group. For example, the halogen atom may be Cl or Br, and the alkyl group may be an alkyl group having 1 to 13 carbon atoms, such as methyl, ethyl or propyl, and the alkoxy group may be an alkoxy group having 1 to 13 carbon atoms such as methoxy, Ethoxy or propoxy, and the aryl group may be an aryl group having 6 to 10 carbon atoms, such as phenyl, chlorophenyl or tolyl.

R ₂ independently represents a hydrocarbon group or a hydroxy group having 1 to 13 carbon atoms. For example, R ₂ is an alkyl group or alkoxy group having 1 to 13 carbon atoms, an alkenyl group or alkenyloxy group having 2 to 13 carbon atoms, a cycloalkyl group or cycloalkoxy group having 3 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, An aralkyl group or an aralkoxy group having 7 to 13 carbon atoms, or an alkaryl group or an alkaryloxy group having 7 to 13 carbon atoms.

R ₃ independently represents an alkylene group having 2 to 8 carbon atoms.

m is independently an integer of 0 to 10, preferably an integer of 0 to 4.

n independently represents an integer of 2 to 1,000, preferably an integer of 2 to 500, more preferably an integer of 5 to 100.

A represents a structure represented by the following formula (2) or (3).

(2)

In Formula 2, -X- is -Y- or -NH-Y-NH-, wherein Y is a linear or branched aliphatic group having 1 to 20 carbon atoms, a cycloalkylene group (e.g., a cycloalkyl group having 3 to 6 carbon atoms Or an arylene group having 6 to 30 carbon atoms, which is substituted or unsubstituted with a halogen atom, an alkyl group, an alkoxy group, an aryl group or a carboxyl group. For example, X may be an aliphatic group substituted with a halogen atom or an unsubstituted aliphatic group, an aliphatic group containing an oxygen, nitrogen or sulfur atom in the main chain, or an aryl group which may be derived from bisphenol A, resorcinol, hydroquinone or diphenyl phenol It can be a ring.

(3)

In Formula 3, R ₄ represents an aromatic or aromatic / aliphatic mixed hydrocarbon group having 6 to 30 carbon atoms or an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Here, R ₄ may have a structure including a halogen atom, oxygen, nitrogen, or sulfur in addition to a carbon atom. For example, R < ₄ > may be phenyl, chlorophenyl or tolyl (preferably phenyl).

The exemplary structure of Formula 2 may be represented by the following formulas (2a) to (2h).

(2a)

(2b)

[Chemical Formula 2c]

(2d)

[Formula 2e]

(2f)

[Chemical Formula 2g]

[Chemical Formula 2h]

In one embodiment, the hydroxy-terminated polysiloxane of Formula 1 may be the reaction product of a hydroxy-terminated siloxane of Formula 1a with an acyl compound (i.e., a hydroxy-terminated siloxane having an ester linkage).

[Formula 1a]

R ₁ , R ₂ , R ₃ , m and n are as defined in the above formula (1).

The hydroxy-terminated siloxane of formula (1a) can be prepared, for example, by synthesizing a compound of formula (1b) having a double bond with a hydroxyl group and a compound of formula (1c) containing silicon at a molar ratio of 2: 1 .

[Chemical Formula 1b]

In Formula 1b, R < _{1 >} And m are the same as defined in the formula (1), and k represents an integer of 1 to 7.

[Chemical Formula 1c]

In the above formula (1c), R ₂ and n are the same as defined in the above formula (1).

)를 사용할 수 있으나, 반드시 이에 한정되는 것은 아니다. 또한 상기 화학식 1a의 히드록시 말단 실록산의 제조와 관련하여 미국특허 US 6,072,011호를 참조할 수 있다.Specifically, the hydroxyl-terminated siloxane of formula (1a) is a siloxane monomer of Dow Corning Corporation

) May be used, but the present invention is not limited thereto. Reference may also be made to U.S. Patent No. 6,072,011 for the preparation of the hydroxy-terminated siloxane of Formula 1a above.

The acyl compound used in the preparation of the hydroxy-terminated polysiloxane of Formula 1 may have, for example, a mixed structure including aromatic, aliphatic, aromatic and aliphatic groups. When the acyl compound is aromatic or mixed, it may have 6 to 30 carbon atoms. When the acyl compound is aliphatic, it may have 1 to 20 carbon atoms. The acyl compound may further contain a halogen, an oxygen, a nitrogen or a sulfur atom.

In another embodiment, the hydroxy-terminated polysiloxane of Formula 1 may be the reaction product of the hydroxy-terminated siloxane of Formula 1a with a diisocyanate compound (i.e., a hydroxy-terminated siloxane having a urethane bond).

Here, the diisocyanate compound may be, for example, 1,4-phenylenediisocyanate, 1,3-phenylenediisocyanate or 4,4'-methylenediphenyl diisocyanate. (4,4'-methylenediphenyl diisocyanate).

In another embodiment, the hydroxy-terminated polysiloxane of Formula 1 may be the reaction product of the hydroxy-terminated siloxane of Formula 1a with a phosphorus-containing compound of Formula 1d (aromatic or aliphatic phosphate compound).

≪ RTI ID = 0.0 &

In the above formula (1d), R ₄ is as defined in formula (3), and R ₅ independently represents a phosphorus atom, a halogen atom, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an aryl group.

The molar ratio of the hydroxy end siloxane of formula (Ia) to the phosphorus-containing compound of formula (I) is preferably in the range of from 3: 1 to 1: 1, more preferably from 2: 1 to 1.5: 1. When the molar ratio of the compound of the formula (1d) to the compound of the formula (1d) is less than 1, the physical properties may be lowered due to the unreacted phosphorus-containing compound. When the molar ratio exceeds 3, it is difficult to expect a sufficient flame- Can be.

Specific examples of the hydroxy-terminated siloxane of the formula (1) obtained by reacting the hydroxy-terminated siloxane of the formula (1a) with the phosphorus-containing compound of the formula (1d) may have the following structure.

R ₁ , R ₂ , R ₃ , m and n are the same as defined in the above formula (1).

The branched polycarbonate block included as a repeating unit in the polysiloxane-branched polycarbonate block copolymer resin used in the composition of the present invention can be obtained by reacting a branched polycarbonate oligomer with the hydroxy-terminated siloxane of the above formula .

There is no particular limitation on the method for producing the branched polycarbonate oligomer. For example, a branched polycarbonate oligomer can be prepared by reacting an oligomeric polycarbonate with a branching agent. Alternatively, it may be prepared by a phosgene method in which a divalent phenol compound and phosgene are mixed together with a branching agent, but is not limited thereto.

The branching agent may be, for example, a branched functional group independently selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NH ₂ ), an acid halide (-COCI) (For example, 3 to 4 organic compounds). Examples of such branching agents include 1,1,1-tris (4-hydroxyphenyl) ethane, THPE, mellitic acid, trimellitic acid, The present invention relates to a process for the preparation of a compound of formula (I), wherein the acid is selected from the group consisting of an acid, trimellitic acid chloride, trimellitic anhydride, pyromellitic acid, resorcycloic acid, resorcinoldehyde, trimellitic trichloride, trimellitic trichloride, trihydroxyflbene derivative (such as 2,4,4-trimethyl-2,4,7-trihydroxyflbene), phloroglucin, But is not limited thereto.

In the preparation of the branched polycarbonate oligomer, preferably 0.001 to 10 mol% of branching agent may be used, preferably 0.01 to 3 mol%, more preferably 0.01 to 3 mol%, based on the amount of the divalent phenol compound used, Preferably, 0.03 to 1.5 mol% of a branching agent can be used. If the amount of the branching agent used is too small, the impact resistance and flame retardancy of the resultant copolymer are unsatisfactory. On the other hand, if the amount is too large, separation may occur during injection and transparency may be deteriorated.

The divalent phenol compound used for preparing the branched polycarbonate oligomer may be, for example, a compound represented by the following formula (4).

[Chemical Formula 4]

In Formula 4, L represents a linear, branched or cyclic alkylene group having no functional group or a straight, branched or cyclic alkylene group containing a functional group such as sulfide, ether, sulfoxide, sulfone, ketone, phenyl, isobutylphenyl, Or a cyclic alkylene group. Preferably, L may be a straight, branched or cyclic alkylene group of 1 to 10 carbon atoms. R ₆ and R ₇ may independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group. a and b independently represent an integer of 0 to 4;

The compound of Formula 4 may be, for example, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, bis ) - (4-isobutylphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1- Bis (4-hydroxyphenyl) ethane, 1-naphthyl-1,1-bis (4-hydroxyphenyl) (4-hydroxyphenyl) decane, 2-methyl-1,1-bis (4-hydroxyphenyl) propane, 2,2- Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) pentane, Bis (4-hydroxyphenyl) propane, bis (3-methyl-4-hydroxyphenyl) propane, 2,2- , 4,4-bis (4-hydroxyphenyl) heptane, diphenyl-bis (4-hydroxyphenyl) Resorcinol, Hydroquine, 4,4'-dihydroxyphenyl ether [bis (4-hydroxyphenyl) ether], 4,4'-dihydroxy- Dihydroxy-3,3'-dichlorodiphenyl ether, bis (3,5-dimethyl-4-hydroxyphenyl) ether, bis (3,5- Hydroxyphenyl) ether, 1,4-dihydroxy-2,5-dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, 4,4'-dihydroxydiphenol [p, p Dihydroxyphenyl], 3,3'-dichloro-4,4'-dihydroxyphenyl, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1- (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl) cyclohexane, (4-hydroxyphenyl) decane, 1,1-bis (4-hydroxyphenyl) cyclododecane, 4-bis (4-hydroxyphenyl) propane, 1,4-bis 4-hydroxyphenyl) butane, 1,4-bis (4-hydroxyphenyl) isobutane, 2,2- (3,5-dimethyl-4-hydroxyphenyl) methane, bis (3,5-dichloro-4-hydroxyphenyl) methane, 2,2- Bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis , 4-bis (4-hydroxyphenyl) -2-methylbutane, 4,4'-thiodiphenol [bis (4-hydroxyphenyl) sulfone] Bis (4-hydroxyphenyl) sulfone, bis (3-chloro-4-hydroxyphenyl) sulfone, bis (3,5-dibromo-4-hydroxyphenyl) sulfoxide, 4,4'-dihydroxybenzophenone, 3 , 3 ', 5,5'-tetramethyl-4,4'-dihydroxybenzo It may be a non-4,4'-dihydroxy-diphenyl, methyl hydroquinone, 1,5-dihydroxynaphthalene, and 2,6-dihydroxy naphthalene, but is not limited thereto. Representative examples include 2,2-bis (4-hydroxyphenyl) propane (bisphenol A). Other dihydric phenols can be found in U.S. Patents US 2,999,835, US 3,028,365, US 3,153,008, US 3,334,154, and US 4,131,575, and the dihydric phenols may be used singly or in combination with one another Can be used in combination.

According to one embodiment of the present invention, the divalent phenol compound (for example, bisphenol A) is added to an aqueous alkaline solution, and the resultant mixture is mixed with an organic solvent (for example, dichloromethane) To prepare an oligomeric polycarbonate wherein the molar ratio of the phosgene to the divalent phenol compound can be maintained in the range of about 1: 1 to 1.5: 1, preferably about 1: 1 to 1.2: 1, The oligomeric polycarbonate produced may have a molecular weight of 800 to 20,000. A branched polycarbonate oligomer may be formed by adding a branching agent to the organic phase-water mixture comprising the oligomeric polycarbonate thus prepared, and gradually introducing a molecular weight regulator and a catalyst.

According to another embodiment of the present invention, the divalent phenol compound (for example, bisphenol A) and a branching agent are added to an aqueous alkali solution, and the resulting mixture is mixed with an organic solvent (for example, dichloromethane) (Wherein the molar ratio of the phosgene to the divalent phenol compound can be maintained in the range of about 1: 1 to 1.5: 1, preferably about 1: 1 to 1.2: 1), wherein stepwise molecular weight A branched polycarbonate oligomer may be formed by introducing a modifier and a catalyst.

The polycarbonate oligomerization reaction can be generally carried out at a temperature in the range of about 15 to 60 占 폚. For adjusting the pH of the reaction mixture, alkali metal hydroxides may be introduced into the reaction mixture. The alkali metal hydroxide may be, for example, sodium hydroxide.

As the molecular weight modifier, a monofunctional compound similar to the monomer used in the production of the polycarbonate may be used. The monofunctional material may be selected from, for example, p-isopropylphenol, p-tert-butylphenol (PTBP), p-cumyl phenol, p- Phenol-based derivatives such as isononylphenol, or aliphatic alcohols. Preferably, p-tert-butylphenol (PTBP) may be used.

As the catalyst, a polymerization catalyst and / or a phase transfer catalyst may be used. The polymerization catalyst may be, for example, triethylamine (TEA), and the phase transfer catalyst may be a compound of the following formula (5).

[Chemical Formula 5]

(R ₈ ) ₄ Q ⁺ Z ^-

In Formula 5, R ₈ may independently represent an alkyl group having 1 to 10 carbon atoms, Q may represent nitrogen or phosphorus, and Z may represent a halogen atom or -OR ₉ . Here, R ₉ may represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms.

The phase transfer catalysts include, for _{example, [CH 3 (CH 2)} 3] 4 NZ, [CH 3 (CH 2) 3] 4 PZ, [CH 3 (CH 2) 5] 4 NZ, [CH 3 (CH 2 ) ₆ ] ₄ NZ, [CH ₃ (CH ₂ ) ₄ ] ₄ NZ, CH ₃ [CH ₃ (CH ₂ ) ₃ ] ₃ NZ and CH ₃ [CH ₃ (CH ₂ ) ₂ ] ₃ NZ. Wherein Z may be Cl, Br or -OR < ₉ >. Here, R ₉ may be a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms.

The content of the phase transfer catalyst is preferably about 0.1 to 10 wt% of the reaction mixture. When the content of the phase-transfer catalyst is less than 0.1% by weight, the reactivity may be deteriorated. When the amount of the phase-transfer catalyst is more than 10% by weight, precipitation may occur in the precipitate, and the transparency of the resultant copolymer may be deteriorated.

After the branched polycarbonate oligomer is formed as described above, the organic phase dispersed in methylene chloride is washed with alkali and separated. Subsequently, the organic phase is washed with 0.1N hydrochloric acid solution and then washed with distilled water 2-3 times.

When the cleaning is completed, the concentration of the organic phase dispersed in methylene chloride is adjusted to a constant level and granulation is performed using a predetermined amount of secondary distilled water at 70 to 80 ° C. If the temperature of the second distilled water is less than 70 ° C, the assembling time may be excessively long due to a slower rate of assembly, and it may be difficult to obtain a polycarbonate having a uniform particle size if it exceeds 80 ° C. When the assembly is completed, it is preferable to firstly dry at 100 to 110 ° C for 5 to 10 hours and secondly to 110 to 120 ° C for 5 to 10 hours.

The prepared branched polycarbonate oligomer preferably has a viscosity average molecular weight of 10,000 to 150,000. If the average molecular weight is less than 10,000, the mechanical properties may be significantly deteriorated. If the average molecular weight is more than 150,000, there may be a problem in resin processing due to an increase in melt viscosity.

In the polysiloxane-branched polycarbonate block copolymer resin, the content ratio of the hydroxy-terminated polysiloxane: branched polycarbonate block of formula (1) may be in the range of from 0.1: 1 to 10: 1, preferably 0.2 : 1 to 5: 1, more preferably 0.4: 1 to 2.5: 1. If the relative content of the siloxane moiety in the copolymer is less than this range, the flame retardancy and the low temperature impact strength may be lowered. On the other hand, if it is more than this, properties such as transparency, fluidity, heat resistance and room temperature impact strength may be lowered and the manufacturing cost may increase.

The polysiloxane-branched polycarbonate block copolymer has a viscosity average molecular weight (Mv), as measured in a methylene chloride solution, of preferably 15,000 to 200,000, more preferably 15,000 to 70,000. If the viscosity average molecular weight of the copolymer is less than 15,000, the mechanical properties may be significantly deteriorated. When the viscosity average molecular weight is more than 200,000, the resin may have a problem in processing due to an increase in melt viscosity.

In the flame retardant resin composition of the present invention, the content of the polysiloxane-branched polycarbonate block copolymer resin is preferably 10 to 95 parts by weight, more preferably 20 to 95 parts by weight, still more preferably 20 to 95 parts by weight, May be 30 to 90 parts by weight. If the content of the polysiloxane-branched polycarbonate block copolymer resin in the resin composition of the present invention is less than 10 parts by weight per 100 parts by weight of the total composition, sufficient flame retardancy can not be exhibited and impact resistance may be lowered. On the other hand, Physical properties such as fluidity and heat resistance may be deteriorated.

(B) Polyethylene terephthalate  Suzy( PET  Suzy)

The flame retardant resin composition of the present invention includes a polyethylene terephthalate resin. According to a preferred embodiment of the present invention, as the polyethylene terephthalate resin, a polymer having a repeating unit represented by the following formula (6) may be used:

[Chemical Formula 6]

In the above formula (6), n represents an integer of 2 or more, preferably an integer of 95 to 120.

The polyethylene terephthalate resin used in the flame retardant resin composition of the present invention is not particularly limited within the range defined by the above formula but preferably has a melting point of 255 to 265 DEG C and an intrinsic viscosity of 0.43 to 0.82 dl / It is more preferable since it is excellent in moldability.

In the flame retardant resin composition of the present invention, the content of the polyethylene terephthalate resin is preferably 5 to 90 parts by weight, more preferably 5 to 80 parts by weight, still more preferably 10 to 70 parts by weight, . If the content of the polyethylene terephthalate resin in the resin composition of the present invention is less than 5 parts by weight per 100 parts by weight of the composition, there may be a problem in processing depending on the flowability. On the contrary, if the content is more than 90 parts by weight,

The flame retardant resin composition of the present invention may contain, in addition to the above-mentioned polysiloxane-branched polycarbonate block copolymer resin and polyethylene terephthalate resin, one or more additional components as needed within the scope of achieving the object of the present invention can do.

The flame retardant resin composition of the present invention may further comprise a polysiloxane-polycarbonate resin different from the polysiloxane-branched polycarbonate block copolymer resin (A). As such additional polysiloxane-polycarbonate resin, for example, a polysiloxane-linear polycarbonate copolymer resin containing a hydroxy-terminated siloxane and a linear polycarbonate block of formula (1) described above as repeating units may be used.

When the flame retardant resin composition of the present invention comprises such additional polysiloxane-polycarbonate resin, the content may be 1 to 30 parts by weight per 100 parts by weight of the composition, wherein the polysiloxane-branched polycarbonate block (A) The copolymer resin may be used in an amount of 20 to 90 parts by weight, and the (B) polyethylene terephthalate resin may be used in an amount of 5 to 60 parts by weight.

The flame retardant resin composition of the present invention may further comprise an impact modifier to further improve the impact strength. The flame retardant resin composition of the present invention may exhibit excellent impact resistance without using any additional impact modifier, but this does not mean that the use of the impact modifier in the flame retardant resin composition of the present invention is excluded.

The impact modifier that can be used in the present invention is preferably an acrylic impact modifier, and more preferably a core-shell type acrylic impact modifier. Compared with a core-shell type MBS impact modifier generally used in the alloys of polycarbonate resin and polyester resin, the acrylic impact modifier has a core-butadiene rubber structure Has a relatively higher glass transition temperature and thermal stability than MBS type impact modifier, and has a short cycle time in injection molding. The acrylic material used as the core is not particularly limited, but is ethyl acryl rubber, butyl acryl rubber or a combination thereof, preferably butyl acryl rubber, and the preferred core diameter is 200 to 350 nm. The acrylic material used as the shell is not particularly limited, but styrene acrylonitrile, polymethyl methacrylate or a combination thereof, preferably polymethyl methacrylate.

When an impact modifier is used in the flame retardant resin composition of the present invention, the content of the impact modifier may be 1 to 10 parts by weight, more specifically 1 to 5 parts by weight, per 100 parts by weight of the composition.

The flame retardant resin composition of the present invention may further comprise a flame retardant such as a halogen flame retardant and / or a phosphorus flame retardant to further improve the flame retardancy. The flame retardant resin composition of the present invention can remarkably improve the flame retardancy without using or minimizing the use of these flame retardants. However, this does not mean that the use of these flame retardants is excluded in the flame retardant resin composition of the present invention, To the extent that the object can be achieved, a suitably reduced amount of a halogen-based and / or phosphorus-based flame retardant than conventionally used can be used.

When a halogen-based flame retardant is used in the flame retardant resin composition of the present invention, a brominated epoxy-based flame retardant, which is a bromine-based compound, may be preferably used. The brominated epoxy flame retardant has excellent thermal stability and heat aging characteristics. The brominated epoxy flame retardant usable in the present invention is preferably a high molecular weight brominated epoxy flame retardant, more preferably an average molecular weight of 58,000 to 68,000, and more preferably an average molecular weight of 61,000 to 65,000.

The brominated epoxy flame retardant that can be used in the present invention includes, but is not limited to, polymers having repeating units of the following formula:

(7)

In formula (7), 1 represents an average degree of polymerization of 95 to 120, preferably an average degree of polymerization in the range of 105 to 115.

The brominated epoxy flame retardant of the formula (7) is a non-blooming type having a bromine content of 53% by weight and a specific gravity of 1.8. Also, it is different from polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) regulated by the Restriction of Hazardous Substances (RoHS) restriction. And can be widely applied to housings of electric / electronic parts.

When a halogen-based flame retardant is used in the flame retardant resin composition of the present invention, the content thereof may be 1 to 15 parts by weight, more specifically 1 to 10 parts by weight, per 100 parts by weight of the total composition.

On the other hand, when a phosphorus-based flame retardant is used in the flame retardant resin composition of the present invention, it can be used without any particular limitation if it is a monomer-type phosphorus-based flame retardant. Preferred phosphorus flame retardants are triphenyl phosphate, tris (2,6-xylyl) phosphate, resorcinol bis (di xylenelyl phosphate), 4,4'-biphenyl- bis (di xylenelylphosphate), bisphenol A bis (Di-xylene ylphosphate) or hydroquinone bis (di-xylene yl phosphate), and more preferably triphenyl phosphate.

When a phosphorus-based flame retardant is used in the flame retardant resin composition of the present invention, its content may be 0.1 to 1 part by weight, more specifically 0.1 to 0.5 part by weight per 100 parts by weight of the composition.

Further, the flame retardant resin composition of the present invention may further comprise an auxiliary flame retardant. When an auxiliary flame retardant is used in the flame retardant resin composition of the present invention, the use of a fluorinated polyolefin resin forms a fibrous network structure in the composition to suppress the flow of the base resin at the time of combustion and increase the shrinkage rate, Dripping can be prevented. Although not limited thereto, fluorinated polyolefin-based resins usable as auxiliary flame retardants in the present invention include polytetrafluoroethylene (PTFE); Polyvinylidene fluoride; Copolymers of tetrafluoroethylene and vinylidene fluoride; Copolymers of tetrafluoroethylene and hexafluoropropylene; Styrene acrylonitrile-modified polytetrafluoroethylene, acrylic-modified polytetrafluoroethylene or a combination thereof, preferably acrylic-modified polytetrafluoroethylene. More preferably, the amount of polytetrafluoroethylene in the acrylic modified polytetrafluoroethylene is from 45 to 55% by weight, and the acrylic modified polytetrafluoroethylene is preferably a powder or granule type. The fluorinated polyolefin-based resins exemplified above may be used independently of each other, or a mixture of two different types may be used.

When an auxiliary flame retardant is used in the flame retardant resin composition of the present invention, its content may be preferably 0.1 to 2 parts by weight, more preferably 0.1 to 1 part by weight per 100 parts by weight of the composition. If the amount of the auxiliary flame retardant is less than 0.1 part by weight per 100 parts by weight of the composition, the effect of improving flame retardancy may be insufficient. If the amount is more than 2 parts by weight, there is a problem in extrusion processing, and flowability and impact resistance may be lowered.

In addition to the above-described components, the flame retardant resin composition of the present invention may further contain conventional additives such as heat stabilizers, antioxidants, nucleating agents, lubricants, pigments, dyes, light stabilizers or black master batches, May be further included.

But are not limited to, the thermal stabilizers that may be used in the present invention include bisphenol A epoxy resins, monocarbodiimides or polycarbodiimides; Antioxidants include tris (nonylphenyl) phosphite, (2,4,6-tri-tert-butylphenyl) (2-butyl- Bis (2,4-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite or bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, Organic antioxidants such as distearyl pentaerythritol diphosphite, antioxidants such as pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate or octadecyl- A phenol-based antioxidant such as - (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, a thioester-based antioxidant such as pentaerythritol tetrakis (4,6-di-tert-butylphenyl) phosphate; the lubricant comprises a phenol, a silane, an ionomer, sodium 2,2'-methylene- (2'-hydroxyphenyl) -benzotriazole, 2-hydroxy-benzophenone, 2- (2'-hydroxyphenyl) benzothiophene, (1-methyl-1-phenylethyl) phenol, 2- (4,6-di Phenyl-1,3,5-triazin-2-yl) -5-hexyloxy-phenol, 2- (2H-benzotriazol- Methylbutyl) phenol or 2,2'-methylenebis (6- (2H-benzotriazol-2-yl)) - 4- (1,1,3,3-tetramethylbutyl) phenol; The amount of the additive that can be included in the flame retardant resin composition of the present invention can be selected without limitation within the range of usually used, but preferably the flame retardant resin composition of the present invention Are each independently from 0.2 to 3 parts by weight based on 100 parts by weight.

According to another aspect of the present invention, there is provided a process for preparing a polycarbonate oligomer comprising: (1) preparing a branched polycarbonate oligomer; (2) copolymerizing the branched polycarbonate oligomer prepared in the step (1) and the hydroxy-terminated polysiloxane of the formula (1) to prepare a polysiloxane-branched polycarbonate block copolymer resin; And (3) melt-mixing the polysiloxane-branched polycarbonate block copolymer resin prepared in the step (2) and a polyethylene terephthalate resin.

According to one embodiment of the present invention, the hydroxy-terminated polysiloxane is added to the organic phase-water mixture containing the prepared branched polycarbonate oligomer and the polysiloxane-branched polycarbonate block air A coalesced resin can be produced. The molecular weight regulator and the catalyst are as described above.

Also, according to one embodiment, the organic phase in which the produced copolymer is dispersed in methylene chloride is subjected to alkali washing and separation, followed by washing the organic phase with 0.1N hydrochloric acid solution and then repeating the reaction with distilled water for 2 to 3 times After the washing is completed, the concentration of the organic phase dispersed in methylene chloride is adjusted to be constant, and granulation is performed using a predetermined amount of pure water at 70 to 80 ° C. If the pure water temperature is less than 70 캜, the assembling speed may become slow and the assembly time may become very long. If the pure water temperature exceeds 80 캜, it may become difficult to obtain the shape of the copolymer at a constant size. When the assembly is completed, it is preferable to firstly dry at 100 to 110 ° C for 5 to 10 hours and secondly at 110 to 120 ° C for 5 to 10 hours.

The resin composition of the present invention can be obtained by melt-mixing the polysiloxane-branched polycarbonate block copolymer resin and the polyethylene terephthalate resin prepared as described above. The melt mixing of the resin components can be carried out using conventional methods and equipment, for example, by mixing the components in a Henschel mixer and uniformly dispersing them, and then extruding them at a temperature of 240 to 270 캜 in a biaxial melt mixing extruder.

According to another aspect of the present invention, there is provided a molded article of the flame retardant thermoplastic resin composition of the present invention as described above.

The method of molding the composition of the present invention into a molded article is not particularly limited, and a molded article can be manufactured by a method generally used in the plastic molding field.

The molded article produced from the flame retardant thermoplastic resin composition of the present invention can be usefully applied to interior materials and exterior materials that require flame retardancy and impact resistance, such as computer terminals, office equipment, and housings for electrical and electronic products.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the scope of the present invention is not limited thereto.

[ Example ]

Manufacturing example  1: hydroxy terminal Polysiloxane  Produce

A condenser was attached to a 500 mL three-necked flask. 0.4 mol of monomer BY16-799 of Dow corning was dissolved in 300 mL of chloroform under nitrogen atmosphere, and 67 mL of triethylamine (TEA) catalyst was added. After 0.2 mol of terephthaloyl chloride (TCL) was dissolved in 1,000 mL of chloroform while the solution was refluxed, it was added slowly for 1 hour and refluxed for 12 hours. After the solvent of the reaction solution was removed, the solution was dissolved in acetone and washed with hot distilled water. The hydroxy-terminated polysiloxane of Formula 8 was prepared by drying in a vacuum oven for 24 hours. The hydrogen peak of the methylene group of the polysiloxane observed at 2.6 ppm by H-NMR and the hydrogen peak of the benzene ring of TCL observed at 8.35 ppm and the hydrogen peak of the benzene ring of the polysiloxane observed at 6.75 to 7.35 ppm .

[Chemical Formula 8]

Manufacturing example  2: Ground  Polycarbonate Oligomeric  Produce

60 g (0.263 mol) of bisphenol A and 0.274 g (0.0009 mol) of 1.1.1-tris (4-hydroxyphenyl) ethane (THPE) were added to a 1 L three-necked flask, and 330 ml (18.46 g, 0.462 mol) 26.0 g (0.263 mol) of phosgene was collected in methylene chloride and allowed to react slowly while being introduced through a Teflon tube (20 m). The external temperature was maintained at 0 ° C. The reaction product having passed through the tubular reactor was subjected to interfacial reaction in a nitrogen atmosphere for about 10 minutes to prepare an oligomeric polycarbonate having a viscosity average molecular weight of about 1,000. 215 mL of the organic phase and 322 mL of the aqueous phase were collected in a mixture containing the oligomeric polycarbonate prepared above, and 0.948 g (6.31 mmol, p-tert-butylphenol (PTBP), 2.4 mol% based on bisphenol A) and tetrabutylammonium chloride (2.63 mmol, 1 mol% based on bisphenol A) and 0.1 mL of 15 wt% triethylamine (TEA) were mixed and reacted for 30 minutes to obtain a branched polycarbonate An oligomer solution was prepared.

Manufacturing example  3: Polysiloxane - Ground  Preparation of Polycarbonate Block Copolymer Resin

5.4 g of the polysiloxane compound of Formula 8 (9 wt% based on bisphenol A) was added to the branched polycarbonate oligomer solution prepared in Preparation Example 2, and after the layer separation, only the organic phase was sampled, (20% by volume based on the total mixture) and 15 μL of 15% by weight triethylamine were mixed and reacted for 1 hour. Then, 167 μL of 15% by weight triethylamine and 128 g of methylene chloride were added thereto, The reaction was continued for 1 hour. After separating the layers, pure water was added to the organic phase whose viscosity was increased, followed by washing with alkali, followed by separation. Subsequently, the organic phase was washed with a 0.1N hydrochloric acid solution and then washed repeatedly with distilled water two to three times. After the washing was completed and the concentration of the organic phase was kept constant, the organic phase was assembled using a predetermined amount of secondary distilled water at 76 ° C. After the assembly was completed, it was dried at 110 ° C for 8 hours and then at 120 ° C for 10 hours. Whereby a polysiloxane-branched polycarbonate block copolymer resin was prepared.

Manufacturing example  4: Polysiloxane - Preparation of Linear Polycarbonate Copolymer Resins

60 g (0.263 mol) of bisphenol A and 1.1.1-tris (4-hydroxyphenyl) were dissolved in 330 ml (18.46 g, 0.462 mol) of 5.6 wt% sodium hydroxide aqueous solution and then 26.0 g mol) were collected in methylene chloride and allowed to react slowly while passing through a Teflon tube (20 m). The external temperature was maintained at 0 ° C. The reaction product having passed through the tubular reactor was subjected to interfacial reaction under a nitrogen atmosphere for about 10 minutes to prepare a linear oligomeric polycarbonate having a viscosity average molecular weight of about 1,000. 215 mL of the organic phase and 322 mL of the aqueous phase were collected in a mixture containing the oligomeric polycarbonate prepared above, and 0.948 g (6.31 mmol, p-tert-butylphenol (PTBP), 2.4 mol% based on bisphenol A) and tetrabutylammonium chloride (2.63 mmol, 1 mol% based on bisphenol A) and 0.1 mL of 15 wt% triethylamine (TEA) were mixed and reacted for 30 minutes to obtain a linear polycarbonate oligomer solution .

Then, after 5.4 g of the polysiloxane compound (9 wt% based on bisphenol A) was separated into the linear polycarbonate oligomer solution prepared above, only the organic phase was sampled and 283 g of the same amount of methylene chloride as that of the organic phase, 0.92 N (20% by volume based on the total mixture) and 15 μl of 15% by weight triethylamine were mixed and reacted for 1 hour. Further, 167 μl of 15% by weight triethylamine and 128 g of methylene chloride were added thereto and further reacted for 1 hour . After separating the layers, pure water was added to the organic phase whose viscosity was increased, followed by washing with alkali, followed by separation. Subsequently, the organic phase was washed with a 0.1N hydrochloric acid solution and then washed repeatedly with distilled water two to three times. After the washing was completed and the concentration of the organic phase was kept constant, the organic phase was assembled using a predetermined amount of secondary distilled water at 76 ° C. After the assembly was completed, it was dried at 110 ° C for 8 hours and then at 120 ° C for 10 hours.

Example  1-4

The components shown in the following Table 1 were introduced into a Henschel mixer in the amounts shown in Table 1, mixed and homogeneously dispersed and extruded at a temperature of 240 to 270 ° C in a biaxial melt mixing extruder having L / D = 40 and? = 25 mm To prepare pellets.

As the polysiloxane-branched polycarbonate block copolymer resin, those prepared in Preparation Example 3 were used.

Example  5

The resin compositions were prepared in the form of pellets in the same manner as in Examples 1 to 4, using the ingredients shown in the following Table 1 in the contents shown in Table 1.

Except that the polysiloxane-branched polycarbonate block copolymer resin was prepared in the same manner as in Preparation Example 3, except that 9 g of the polysiloxane compound (8) (15 wt% based on bisphenol A) was used as the polysiloxane-branched polycarbonate block copolymer resin.

Example  6

The resin compositions were prepared in the form of pellets in the same manner as in Examples 1 to 4, using the ingredients shown in the following Table 1 in the contents shown in Table 1.

As the polysiloxane-branched polycarbonate block copolymer resin, 110 mL of an aqueous sodium hydroxide solution having a concentration of 0.81 N was used, and 0.395 g (2.62 mmol, p-tert-butylphenol (PTBP) (15% by weight based on bisphenol A) was added to the branched polycarbonate oligomer solution prepared in the same manner as in Preparation Example 2, except for using the polysiloxane compound of formula Were used.

Comparative Example  1 to 8

The resin compositions were prepared in the form of pellets in the same manner as in Examples 1 to 4, using the ingredients shown in the following Table 1 in the contents shown in Table 1.

The resin composition pellets prepared for each of the Examples and Comparative Examples were dried in a hot-air drier at 80 to 100 ° C. for 4 hours or more, and injection-molded at 240 to 270 ° C. to prepare specimens. The properties of the prepared specimens were measured and evaluated in the following Table 1, and the results are shown in Table 1 below.

The copolymer identification method and the method of measuring the properties of the specimen are as follows.

(1) H-NMR (Nuclear Magnetic Resonance Spectrometer): Measured using Avance DRX 300 from Bruker. The peak of the methyl group of the dimethylsiloxane observed at 0.2 ppm by H-NMR and the hydrogen peak at the carbon adjacent to the benzene ring of the silicon branching agent observed at 2.6 ppm and the hydrogen peak at the benzene ring of the silicon branching agent observed at 3.9 ppm It was confirmed that the branched polycarbonate was synthesized with a peak of the methoxy group.

(2) Viscosity average molecular weight: The viscosity of the methylene chloride solution was measured at 20 占 폚 using a Ubbelohde Viscometer, and the intrinsic viscosity [?] Was calculated from the following formula.

^{[η] = 1.23 × 10 -5} Mv 0 .83

(3) Impact strength: The impact strength was measured at room temperature (23 ° C) using an impact tester (RESIL IMPACTOR manufactured by CEAST). [Unit: kgf · cm / cm]

(4) Flammability: Measured according to the UL-94 flame retardancy test method prescribed by Underwriter's Laboratory Inc. (UL) of the United States. This method is a method of evaluating the flame retardancy from the burning time and dripping property after attaching the flame of the burner to the vertically fixed specimen of constant size for 10 seconds. The burning time is the length of time the specimen continues to burn during the flame after the flame has been removed, and the burning of the cotton by the drip is carried out by dripping water from the specimen for the label, about 300 mm below the bottom of the specimen The grades of flame retardancy are divided as follows (NG in Table 1 means unfavorable flame retardance, which means defective).

[Description of ingredients used]

PET: Polyethylene terephthalate resin having an intrinsic viscosity of 0.64 dl / g

Linear Si-PC: Polysiloxane-linear polycarbonate copolymer resin prepared in Production Example 4

Branched Si-PC: polysiloxane-branched polycarbonate block copolymer resin

PC: commercialized branched polycarbonate resin (Samyang, TRIREX 3026B, Mv: 26,000)

Impact reinforcing agent: acrylic impact modifier (KANKEACE M400, KANKEKA)

Flame retardant 1: Halogen-based flame retardant (brominated epoxy polymer, F-2400H, DSBG)

Flame Retardant 2: Phosphorous flame retardant (aromatic polyphosphate, PX200, manufactured by Daihachi)

Auxiliary flame retardant: Fluorinated polyolefin resin (Teflon 800J, DuPont)

As shown in Table 1, the resin compositions of Examples 1 to 6 according to the present invention exhibited flame retardancy grade V0 at specimen thicknesses of 2 mm and 3 mm, respectively, and their impact strength was also excellent. On the other hand, in Comparative Examples 1, 2 and 6, the flame retardancy was excellent but the impact resistance was poor. In Comparative Examples 4, 7 and 8, the impact resistance was poor but the flame retardancy was poor. Comparative Examples 3 and 5 , Both the impact resistance and the flame retardancy were poor.

Claims (17)

(A) a flame retardant thermoplastic resin composition comprising a polysiloxane-branched polycarbonate block copolymer resin containing a hydroxy-terminated polysiloxane of the following formula (1) and a branched polycarbonate block as repeating units and (B) a polyethylene terephthalate resin:

[Chemical Formula 1]

In Formula 1,
R ₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an aryl group,
R ₂ independently represents a hydrocarbon group or a hydroxy group having 1 to 13 carbon atoms,
R ₃ independently represents an alkylene group having 2 to 8 carbon atoms,
m is independently an integer of 0 to 4,
n independently represents an integer of 1 to 200,
A represents a structure represented by the following formula (2) or (3)

(2)

In Formula 2,
Y is a linear or branched aliphatic group having 1 to 20 carbon atoms, a cycloalkylene group, or a substituted or unsubstituted alkylene group substituted with a halogen atom, an alkyl group, an alkoxy group, an aryl group or a carboxyl group, A monocyclic or polycyclic arylene group having 6 to 30 carbon atoms,

(3)

In Formula 3,
R ₄ represents an aromatic or aromatic / aliphatic mixed hydrocarbon group having 6 to 30 carbon atoms or an aliphatic hydrocarbon group having 1 to 20 carbon atoms. The flame-retardant thermoplastic resin composition according to Claim 1, wherein A in Formula (1) represents the structure of Formula (2). The flame-retardant thermoplastic resin composition according to claim 1, wherein A in the formula (1) represents the structure of the formula (3). The flame retardant thermoplastic resin composition of claim 1, wherein the branched polycarbonate block is introduced into the polysiloxane-branched polycarbonate block copolymer by reacting the branched polycarbonate oligomer with a hydroxy-terminated siloxane of formula (I). The method of claim 4, wherein the branched polycarbonate oligomer is prepared by reacting an oligomeric polycarbonate with a branching agent or by a phosgene process wherein the divalent phenol compound and phosgene are mixed together with a branching agent By weight of a flame retardant thermoplastic resin composition. The method of claim 5, wherein the branching agent is a hydroxyl group (-OH), carboxyl group (-COOH), amino group (-NH _2), acid halide (-COCI) and a formyl group independently selected from the group consisting of (-CHO) Wherein the flame retardant thermoplastic resin composition is an organic compound having three or more branching functional groups. The flame-retardant thermoplastic resin composition according to claim 5, wherein 0.001 to 10 mol% of a branching agent is used based on 100 mol% of the amount of the divalent phenol compound used in producing the branched polycarbonate oligomer. The flame-retardant thermoplastic resin composition according to claim 4, wherein the branched polycarbonate oligomer has a viscosity average molecular weight of 800 to 20,000. The flame retardant thermoplastic resin composition according to claim 1, wherein the content ratio of the hydroxy-terminated polysiloxane: branched polycarbonate block of formula (1) in the polysiloxane-branched polycarbonate block copolymer resin is 50 to 99: Composition. The flame-retardant thermoplastic resin composition according to claim 1, wherein the polysiloxane-branched polycarbonate block copolymer resin has a viscosity average molecular weight (Mv) of 15,000 to 200,000. The flame-retardant thermoplastic resin composition according to claim 1, wherein the polyethylene terephthalate resin is a polymer having a repeating unit represented by the following formula (6):

[Chemical Formula 6]

In the above formula (6), n represents an integer of 2 or more. The flame-retardant thermoplastic resin composition according to claim 1, further comprising a polysiloxane-linear polycarbonate copolymer resin. The flame-retardant thermoplastic resin composition according to claim 1, further comprising an impact modifier. The flame-retardant thermoplastic resin composition according to claim 1, further comprising a flame retardant. The flame-retardant thermoplastic resin composition according to claim 1, further comprising an auxiliary flame retardant. (1) preparing a branched polycarbonate oligomer;
(2) copolymerizing the branched polycarbonate oligomer prepared in the step (1) and the hydroxyl-terminated polysiloxane of the following formula (1) to prepare a polysiloxane-branched polycarbonate block copolymer resin; And
(3) melt-mixing the polysiloxane-branched polycarbonate block copolymer resin prepared in the step (2) and a polyethylene terephthalate resin; and

[Chemical Formula 1]

In Formula 1,
R ₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an aryl group,
R ₂ independently represents a hydrocarbon group or a hydroxy group having 1 to 13 carbon atoms,
R ₃ independently represents an alkylene group having 2 to 8 carbon atoms,
m is independently an integer of 0 to 4,
n independently represents an integer of 1 to 200,
A represents a structure represented by the following formula (2) or (3)

(2)

In Formula 2,
Y is a linear or branched aliphatic group having 1 to 20 carbon atoms, a cycloalkylene group, or a substituted or unsubstituted alkylene group substituted with a halogen atom, an alkyl group, an alkoxy group, an aryl group or a carboxyl group, A monocyclic or polycyclic arylene group having 6 to 30 carbon atoms,

(3)

In Formula 3,
R ₄ represents an aromatic or aromatic / aliphatic mixed hydrocarbon group having 6 to 30 carbon atoms or an aliphatic hydrocarbon group having 1 to 20 carbon atoms. 16. A molded article of the flame-retardant thermoplastic resin composition according to any one of claims 1 to 15.