KR101459123B1 - Polyphosphonate, method for preparing thereof and flame retardant thermoplastic resin composition comprising the same - Google Patents

Abstract

(상기 식에서, A는 단일 결합, C₁-C₅의 알킬렌, C₁-C₅의 알킬리덴, C₅-C₆의 시클로알킬리덴, -S- 또는 -SO₂-이고, R은 치환 또는 비치환된 C₆-C₂₀인 아릴기 또는 C₆-C₂₀인 치환 또는 비치환된 아릴옥시기이고, R₁ 및 R₂는 각각 독립적으로 치환 또는 비치환된 C₁ 내지 C₆ 알킬기, 치환 또는 비치환된 C₃ 내지 C₆ 사이클로알킬기, 치환 또는 비치환된 C₆ 내지 C₁₂의 아릴기 또는 할로겐 원자이며, a 및 b는 각각 독립적으로 0 내지 4의 정수, n은 1 내지 500의 정수임.)The present invention relates to a polyphosphonate represented by the following formula (1), wherein the acid value is 5.5 KOH mg / g or less:
[Chemical Formula 1]

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, and R is substituted Or an unsubstituted or substituted C ₆ -C ₂₀ aryl or C ₆ -C ₂₀ substituted or unsubstituted aryloxy; R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to an aryl group or a halogen atom of the C ₁₂ ring, a and b are each independently from 0 to 4 integer, n is from 1 to 500 An integer.)

Description

TECHNICAL FIELD [0001] The present invention relates to a polyphosphonate, a method for producing the same, and a flame retardant thermoplastic resin composition containing the same. BACKGROUND ART [0002]

The present invention relates to a polyphosphonate and a flame retardant thermoplastic resin composition containing the same. More specifically, the present invention relates to a polyphosphonate having an acid value improved by post-treatment with an alkylene oxide in producing a polyphosphonate, and a thermoplastic resin composition using the same as a flame retardant.

A phosphorus-based flame retardant is used as a method for imparting flame retardancy without using a halogen-based flame retardant. Conventionally, monomolecular phosphorus flame retardants such as triphenyl phosphate and resorcinol bisphenolphosphate have been mainly used. However, since such monomolecular phosphorus flame retardants have low molecular weights, they may be volatilized at a high molding temperature during plastic molding, , When a product is used, a mono-molecular phosphorus flame retardant may be extracted into nature and cause environmental pollution. Accordingly, there is an increasing interest in polyphosphonates as polymerizable phosphorus flame retardants. The polymer-type polyphosphonate is superior to the monomolecular phosphorus flame retardant in terms of flame retardancy, mechanical properties, heat resistance and transparency, and is particularly suitable for application to resins requiring high heat resistance and high transparency, such as polycarbonate resins.

Such polyphosphonates can be prepared by deoxidation of diols with phosphonium dichloride. However, phosphonitic chloride has a property of being hydrolyzed and changed into phosphonic acid, which causes a problem of decomposition of the polycarbonate resin and decomposition of the polyphosphonate itself.

As a method of polymerizing polyphosphonate, there are a solution polymerization (US 2534252; 3946093; 3919363), an interfacial polymerization (US 2002/0058779; a melt polymerization (US 3719727; 3829405; 3830771; Since the method does not use phosphonitic chloride but uses phosphonitrialkyl or aryl, there is no problem of hydrolysis, but a dedicated equipment for removing by-products is required, and polymerization conditions are also complicated. On the other hand, In the case of the polymerization method, the polymer end contains a phosphonic chloride and is exposed to the risk of hydrolysis.

Techniques have been developed to attempt endcapping with alcohol to prevent hydrolysis of the terminal phosphonic chloride. However, when the endcapping agent is used in excess, the acid value of the endcapping agent may increase and the polycarbonate resin may be decomposed. In addition, phosphonic acid which has already been hydrolyzed is not easily removed.

Conventionally, a method of neutralizing a base containing an alkali metal is used to lower the acid value. However, in this case, alkali metal ions may remain in the polycarbonate to decompose the polycarbonate.

Therefore, it is necessary to develop a polycarbonate-based flame retardant which has a low acid value but does not retain the agent used for lowering the acid value.

It is an object of the present invention to provide a polyphosphonate having reduced acid value and a process for producing the same.

Another object of the present invention is to provide a process for producing polyphosphonate which can drastically lower the acid value.

Another object of the present invention is to provide a flame retardant thermoplastic resin composition which is excellent in flame retardancy and heat resistance and does not deteriorate other properties by applying the polyphosphonate prepared as described above as a flame retardant.

One aspect of the invention relates to polyphosphonates. The polyphosphonate is a polyphosphonate represented by the following formula (1) and has an acid value of 5.5 mg KOH / g or less:

[Chemical Formula 1]

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, and R is substituted Or an unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to an aryl group or a halogen atom of the C ₁₂ ring, a and b are each independently from 0 to 4 integer, n is from 1 to 500 An integer.)

In an embodiment, the polyphosphonate is characterized by being post-treated with an alkylene oxide.

In an embodiment, the polyphosphonate has the structure of Formula 1-1 and has an acid value of 4.5 KOH mg / g or less:

[Formula 1-1]

Wherein R is a substituted or unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently substituted or unsubstituted C ₁ to C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or an unsubstituted C ₆ to an aryl group or a halogen atom of the C _12, a and b are each independently an integer from 0 to 4; , and n is an integer of 1 to 500)

Another aspect of the present invention relates to a method for producing the polyphosphonate. The process comprises reacting a diol represented by the following formula (2) with a phosphonic dichloride represented by the following formula (3); And treating the reaction product with an alkylene oxide:

(2)

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, R ₁ and R ₂ each independently represent a substituted or unsubstituted C ₁ to C ₆ An alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to C ₁₂ aryl group or a halogen atom, and a and b are each independently an integer of 0 to 4).

(3)

Wherein R is an aryl group having _{6 to 20} carbon atoms or an aryloxy group having _{6 to 20} carbon atoms.

The alkylene oxide may be represented by the following Formula 4:

[Chemical Formula 4]

(Wherein R ₂ is hydrogen, a C ₁ -C ₆ alkyl group, a C ₆ -C ₂₀ An aryl group, a C ₆ -C ₂₀ Substituted alkylaryl group, C ₆ -C ₂₀ Lt; / RTI >

In an embodiment, the alkylene oxide may be added in an amount of 2 to 7 equivalents of the acid value of the reaction product.

In another embodiment, the reaction product can be treated with an alkylene oxide after reacting with 4-cumylphenol to adjust the terminal group.

Another aspect of the present invention relates to a polyphosphonate prepared by the method and having an acid value of 5.5 KOH mg / g or less.

Another aspect of the present invention relates to a flame retardant thermoplastic resin composition comprising the polyphosphonate prepared as described above. The composition may include 0.1 to 30 parts by weight of polyphosphonate per 100 parts by weight of the polycarbonate resin.

The flame retardant thermoplastic resin composition has a number average molecular weight of 12,000 to 20,000 g / mol, a weight average molecular weight of 23,000 to 40,000 g / mol, a heat distortion temperature according to ASTM D648 (1/4 ", 18.6 kg load) 90 to 180 < 0 > C.

INDUSTRIAL APPLICABILITY The present invention can provide a polyphosphonate having a drastically reduced acid value without using an endcapping agent and a method for producing the same. The polyphosphonate prepared as described above is used as a flame retardant to provide a flame retardant thermoplastic resin composition that has excellent flame retardancy and heat resistance and does not deteriorate other physical properties.

The polyphosphonate of the present invention is represented by the following formula (1) and has an acid value of 5.5 KOH mg / g or less:

[Chemical Formula 1]

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, and R is substituted Or an unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to an aryl group or a halogen atom of the C ₁₂ ring, a and b are each independently from 0 to 4 integer, n is from 1 to 500 An integer.)

In one embodiment, the polyphosphonate has the structure of Formula 1-1 and has an acid value of 4.5 KOH mg / g or less:

[Formula 1-1]

Wherein R is a substituted or unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently substituted or unsubstituted C ₁ to C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or an unsubstituted C ₆ to an aryl group or a halogen atom of the C _12, a and b are each independently an integer from 0 to 4; , and n is an integer of 1 to 500)

The polyphosphonate can be prepared by reacting a diol with a phosphonic dichloride.

In an embodiment, the polyphosphonate is obtained by reacting a diol represented by the following formula (2) with a phosphonic dichloride represented by the following formula (3); And treating the reaction product with an alkylene oxide.

(2)

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ to C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to C ₁₂ aryl group or a halogen atom, and a And b are each independently an integer of 0 to 4.)

remind Examples of the diol include 4,4'-dihydroxybiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, 2,4-bis- (4- hydroxyphenyl) (3-chloro-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro -4-hydroxyphenyl) -propane and the like.

(3)

Wherein R is an aryl group having _{6 to 20} carbon atoms or an aryloxy group having _{6 to 20} carbon atoms.

Preferably, one equivalent of phosphonic dichloride can be reacted with one equivalent of the diol.

In one embodiment, the reaction of the diol and the phosphonic dichloride can be carried out in a conventional manner under Lewis acid catalyst. For example, aluminum chloride, magnesium chloride, and the like can be used as the catalyst, but are not limited thereto. The catalyst may be applied in an amount of 0.01 equivalent or more, preferably 0.01 equivalent to 0.1 equivalent based on 1 equivalent of the diol.

In one embodiment, the reaction may be terminated and washed with an acid solution. The acid solution may be phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid or the like, preferably phosphoric acid or hydrochloric acid. At this time, the concentration of the acid solution is preferably 0.1 to 10%, preferably 1 to 5%.

The reaction product washed with the acid solution is reacted with an alkylene oxide represented by the following general formula (4). In the specific example, the reaction may be performed stably by removing moisture through a dehydration process before reacting with the alkylene oxide.

[Chemical Formula 4]

(Wherein R ₂ is hydrogen, a C ₁ -C ₆ alkyl group, a C ₆ -C ₂₀ An aryl group, a C ₆ -C ₂₀ Substituted alkylaryl group, C ₆ -C ₂₀ Aralkyl group.

Wherein R ₂ in the preferred embodiment may be an alkyl group of C ₁ -C _6.

In an embodiment, the alkylene oxide may be added in an amount of 2 to 7 equivalents, preferably 3 to 5 equivalents, of the acid value of the reaction product. Excellent physical property balance can be obtained in the above range.

The reaction between the reaction product and the alkylene oxide is carried out for 1 minute to 24 hours, preferably 1 hour to 20 hours. The reaction temperature may be from 30 to 150 캜.

In the present invention, not only the acid value can be lowered by applying the alkylene oxide as described above, but also the alkylene oxide is washed away in the washing step, so that it has an advantage that the metal ion is not left in the resin when it is applied to the polycarbonate resin .

In another embodiment of the present invention, the reaction product may be further subjected to endcapping in a conventional manner before the reaction with the alkylene oxide. In one embodiment, the reaction product may be reacted with 4-cumylphenol to adjust the terminal group and then treated with an alkylene oxide.

After the reaction between the reaction product and the alkylene oxide, washing and filtration may be further performed.

The polyphosphonate prepared as described above has an acid value of 5.5 KOH mg / g or less, preferably 4.5 KOH mg / g or less, and more preferably 0.01 to 3 KOH mg / g.

Particularly, in the case of polyphosphonates containing biphenyl groups, the acid value is 1 KOH mg / g or less, preferably 0.5 KOH mg / g or less, and more preferably 0.001 to 0.3 KOH mg / g.

Therefore, the polyphosphonate does not cause decomposition of the thermoplastic resin to be mixed because the acid value is very low, and can be preferably applied as a flame retardant.

Another aspect of the present invention relates to a flame retardant thermoplastic resin composition comprising the polyphosphonate.

The kind of the thermoplastic resin is not particularly limited. For example, a styrene resin, a polyamide, a polycarbonate, a polyester, a polyvinyl chloride, a styrenic copolymer resin, a (meth) acrylic resin, a polyphenylene ether resin, and the like can be applied.

The polyphosphonate prepared by the process of the present invention has a low acid value and has flame retardancy, heat resistance and transparency, and therefore can be suitably applied to resins requiring high heat resistance and high transparency.

In one embodiment, the flame retardant thermoplastic resin composition may include 0.1 to 30 parts by weight, preferably 1 to 15 parts by weight, of polyphosphonate based on 100 parts by weight of the polycarbonate resin.

For example, the flame-retardant thermoplastic resin composition has a number-average molecular weight of 12,000 to 20,000 g / mol and a weight-average molecular weight of 23,000 to 40,000 g / mol in accordance with ASTM D648 (1/4 ", 18.6 kg load ) May be 90-180 占 폚.

Hereinafter, the present invention will be described in more detail with reference to Examples, which should be construed as illustrative of the present invention but not limited to the scope of the present invention.

Example

Polyphosphonate  Produce

Example  1 to 5: Bisphenol group  contain Polyphosphonate  Produce

1 equivalent of bisphenol A (manufactured by Kumho) and 0.01 equivalent of aluminum chloride were added to dichlorobenzene (manufactured by samchun), and the mixture was heated to 140 ° C and stirred vigorously. When the temperature was raised to 140 캜, 1 equivalent of phenyl dichloride phosphonate (manufactured by Acros) was mixed with dichlorobenzene (manufactured by samchun), and the reaction was started by dropwise addition. After completion of the dropwise addition, the mixture was further stirred for 8 hours and the reaction was terminated. After completion of the reaction, the reaction product was washed with a hydrochloric acid solution having a concentration of 30% or less, and the water layer was removed. The acid value after the removal of dichlorobenzene was measured by distillation under reduced pressure. 5 equivalents of toluene and an acid value of propylene oxide (manufactured by Aldrich) were charged and the temperature was raised to 130 캜 and stirred for the time shown in Table 1 below. The mixture was cooled to room temperature, washed twice with water, and precipitated in n-hexane to obtain the final product.

Example  6 to 8: Biphenyl group  contain Polyphosphonate  Produce

1 equivalent of biphenol (Songwon) and 0.01 equivalent of aluminum chloride were added to dichlorobenzene (manufactured by samchun), and the mixture was heated to 140 ° C and stirred vigorously. When the temperature was raised to 140 캜, 1 equivalent of phenyl dichloride phosphonate (manufactured by Acros) was mixed with dichlorobenzene (manufactured by samchun), and the reaction was started by dropwise addition. After completion of the dropwise addition, the mixture was further stirred for 8 hours and the reaction was terminated. After completion of the reaction, the reaction product was washed with a hydrochloric acid solution having a concentration of 30% or less, and the water layer was removed. The acid value after the removal of dichlorobenzene was measured by distillation under reduced pressure. 6 equivalents of toluene and an acid value of propylene oxide (manufactured by Aldrich) were charged and the temperature was raised to 130 캜 and stirred for the time shown in Table 2 below. The mixture was cooled to room temperature, washed twice with water, and precipitated in n-hexane to obtain the final product

Comparative Example  One

The procedure of Example 1 was repeated except that the solution was not treated with propylene oxide.

Comparative Example  2

The procedure of Example 6 was repeated except that the solution was not treated with propylene oxide.

The acid values and yields of the polyphosphonates prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were measured in the following manner and are shown in Table 1 below.

Acid value (KOH mg / g): A sample of 1 to 20 g was dissolved in dimethylsulfoxide (50 ml), added with 0.03 ml to 0.2 ml of BTB solution, titrated with 0.1 N NaOH solution, Respectively.

[Formula 1]

Acid value = ((0.1N NaOH solution consumption ml) * (0.1N NaOH solution Factor) * 5.61) / sample amount (g)

Processing time (h) Mountain Example 1 One 5.1 Example 2 2 3.9 Example 3 4 2.0 Example 4 8 1.2 Example 5 20 0.8 Comparative Example 1 0 > 20

As shown in Table 1, the acid values of Examples 1 to 5 to which the method of the present invention was applied were significantly lower than those of Comparative Example 1.

Processing time (h) Mountain Example 6 One 0.1 Example 7 2 0.01 Example 8 4 0.01 Comparative Example 2 0 > 6

As shown in Table 2, the acid values of Examples 6 to 8 to which the method of the present invention was applied are significantly lower than those of Comparative Example 2. [

Production of thermoplastic resin composition

The polyphosphonates prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were introduced into 100 parts by weight of polycarbonate, respectively, and extruded at 200 to 280 ° C in a conventional twin-screw extruder to prepare pellets. After dissolving 0.01 g to 0.015 g of this pellet in 2 mL of MC, about 10 mL of THF was diluted. The dissolved sample was filtered using a 0.45 μm syringe filter, and its molecular weight was measured by gel permeation chromatography (GPC) The flame retardancy was measured at a thickness of 1/8 "according to the flame retardancy regulation. The heat distortion temperature was measured according to ASTM D648 (1/4", 18.6 kg load) (unit: ° C).

Comparative Example 3

Except that PX-200 (manufactured by Daihachi) was used as a flame retardant in 100 parts by weight of a polycarbonate having a number average molecular weight of 12,700 g / mol and a weight average molecular weight of 24,300 g / mol.

No. Composition (Phr.) PC molecular weight Flame retardancy Heat resistance Poly
Phosphonate PX-200 PC Mn
(g / mol) Mw
(g / mol) Example 1 5 - 100 12900 25000 V-2 140 Example 2 5 - 100 14100 26200 V-0 141 Example 3 5 - 100 14100 26800 V-0 141 Example 4 5 - 100 14100 26900 V-0 142 Example 5 5 - 100 14300 27000 V-0 143 Comparative Example 1 5 - 100 11500 22900 V-2 139 Comparative Example 3 - 5 100 12700 24300 V-0 133.3

No. Composition (Phr.) PC molecular weight Flame retardancy Heat resistance Poly
Phosphonate PX-200 PC Mn
(g / mol) Mw
(g / mol) Example 6 5 - 100 12200 24400 V-0 140.5 Example 7 5 - 100 13800 25400 V-0 140.7 Example 8 5 - 100 14500 26000 V-0 141.0 Comparative Example 2 5 - 100 11600 22700 V-2 139 Comparative Example 3 - 5 100 12700 24300 V-0 133.3

As shown in Tables 3 and 4, when the polyphosphonate prepared by the method of the present invention is applied, it can be seen that the polycarbonate is hardly decomposed and the molecular weight is high. In addition, it can be confirmed that the heat resistance is much higher than that of Comparative Example 3 in which the unilamellar phosphorus flame retardant is applied.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (12)

A polyphosphonate represented by the following formula (1), wherein the acid value is 5.5 KOH mg / g or less:

[Chemical Formula 1]

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, and R is substituted Or an unsubstituted or substituted C ₆ -C ₂₀ aryl or C ₆ -C ₂₀ substituted or unsubstituted aryloxy; R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to an aryl group or a halogen atom of the C ₁₂ ring, a and b are each independently from 0 to 4 integer, n is from 1 to 500 An integer.)
The polyphosphonate according to claim 1, wherein the polyphosphonate is post-treated with an alkylene oxide.
The polyphosphonate according to claim 1, wherein the polyphosphonate has a structure represented by the following formula (1-1):

[Formula 1-1]

Wherein R is a substituted or unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently substituted or unsubstituted C ₁ to C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or an unsubstituted C ₆ to an aryl group or a halogen atom of the C _12, a and b are each independently an integer from 0 to 4; , and n is an integer of 1 to 500)
The polyphosphonate according to claim 1, wherein the polyphosphonate has an acid value of 4.5 KOH mg / g or less.
Reacting a diol represented by the following formula (2) with a phosphonic dichloride represented by the following formula (3); And
Treating the reaction product with an alkylene oxide;
Wherein the polyphosphonate is represented by the following general formula (1): < EMI ID =

[Chemical Formula 1]

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, and R is substituted Or an unsubstituted C ₆ -C ₂₀ aryl group or a substituted or unsubstituted C ₆ -C ₂₀ aryloxy group, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to an aryl group or a halogen atom of the C ₁₂ ring, a and b are each independently from 0 to 4 integer, n is from 1 to 500 An integer.)

(2)

Wherein A is a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ to C ₆ alkyl group, a substituted or unsubstituted C ₃ to C ₆ cycloalkyl group, a substituted or unsubstituted C ₆ to C ₁₂ aryl group or a halogen atom, and a And b are each independently an integer of 0 to 4.)

(3)

Wherein R is an aryl group having _{6 to 20} carbon atoms or an aryloxy group having _{6 to 20} carbon atoms.
6. The method according to claim 5, wherein the alkylene oxide is represented by the following formula (4)
[Chemical Formula 4]

(Wherein R ₂ is hydrogen, a C ₁ -C ₆ alkyl group, a C ₆ -C ₂₀ aryl group, a C ₆ -C ₂₀ alkyl substituted aryl group, or a C ₆ -C ₂₀ aralkyl group).
The method according to claim 5, wherein the alkylene oxide is added in an amount of 2 to 7 equivalents based on the acid value of the reaction product.
6. The method of claim 5, wherein the reaction product is reacted with 4-cleaved phenol to adjust the terminal group and then treated with an alkylene oxide.
9. A polyphosphonate prepared by the process of any one of claims 5 to 8 and having an acid value of 5.5 KOH mg / g or less.
A flame retardant thermoplastic resin composition comprising the polyphosphonate of claim 9.
The flame-retardant thermoplastic resin composition according to claim 10, wherein the composition comprises 0.1 to 30 parts by weight of the polyphosphonate based on 100 parts by weight of the polycarbonate resin.
The flame-retardant thermoplastic resin composition according to claim 11, wherein the flame-retardant thermoplastic resin composition has a number-average molecular weight of 12,000 to 20,000 g / mol and a weight-average molecular weight of 23,000 to 40,000 g / mol, according to ASTM D648 (1/4 " And the heat distortion temperature is 90 to 180 占 폚.