WO2013100288A1 - Branched polycarbonate-polysiloxane copolymer and preparation method thereof - Google Patents

Abstract

A branched polycarbonate-polysiloxane copolymer of the present invention is obtained from an aromatic dihydroxy compound, a carbonate precursor, a siloxane compound, and a branching agent, wherein the siloxane compound is a compound represented by chemical formula 2 of claim 1, a compound represented by chemical formula 3 of claim 1, or a combination thereof. The branched polycarbonate-polysiloxane copolymer has a Mark-Houwink constant which can be equal to about 0.50 or more and less than about 0.65, and has excellent processability due to low temperature impact resistance, chemical resistance and high temperature flowability.

Description

Branched Polycarbonate-Polysiloxane Copolymer and Method for Making the Same

The present invention relates to branched polycarbonate-polysiloxane copolymers and methods for their preparation. More specifically, the present invention relates to a branched polycarbonate-polysiloxane copolymer excellent in workability according to low temperature impact resistance, chemical resistance, and high temperature fluidity, and a method of manufacturing the same.

Polycarbonate is a polymer having excellent impact strength, resin stability, and optical properties, and is used as an exterior material for automobiles, automotive materials, building materials, optical lenses, and safety products that require transparency.

In recent years, the use of such polycarbonate has been further expanded, many researches for improving the properties of the polycarbonate for various applications. In particular, many examples have been reported of controlling various properties by copolymerizing two or more kinds of diols having different structures or by including polymers having different structures in the polycarbonate backbone. For example, Korean Patent Laid-Open Publication No. 2009-0035031 discloses that one wants to improve chemical resistance and flame retardant properties by copolymerizing a specific structure with polycarbonate.

In particular, many studies have been conducted to increase the limited chemical resistance of polycarbonate resins. This is because when the polycarbonate resin is used as the exterior material of the electrical and electronic products, the dilution solvent of the paint may penetrate into the polycarbonate resin and lower the mechanical properties. In order to solve this problem, there have been technical attempts to blend polycarbonate and other thermoplastic resins to improve the physical properties of the polycarbonate. However, such technical attempts have problems in that chemical resistance is improved, but impact resistance or transparency is not secured.

For example, US Pat. No. 4,188,314 discloses moldings having improved chemical resistance, including polycarbonates and copolyesters. However, the molding could not obtain sufficient impact strength.

U.S. Pat. No. 4,634,737 discloses resin compositions consisting of copolycarbonates having 25 to 90 mole percent ester bonds and copolyesters and olefin acrylate copolymers, while these compositions have improved chemical resistance, but have very high transparency. Lowers.

Another technical attempt is to increase chemical resistance by introducing other polymers into the polycarbonate backbone. In particular, studies on polycarbonates including polysiloxane structures have been conducted, but most of them have increased chemical resistance and impact resistance, while decreasing transparency.

All of the polycarbonates in which the other polymer is introduced into the main chain have a linear structure. Such linear polycarbonate resins have high impact resistance at room temperature, but have a characteristic of rapidly decreasing impact strength after coating or below -30 ° C. . In addition, the linear polycarbonate resin does not change in viscosity even when high shear stress is applied during extrusion. That is, in the case of blow molding, it is difficult to mold a product having a uniform thickness due to the low viscosity coefficient.

It is an object of the present invention to provide a branched polycarbonate-polysiloxane copolymer having excellent low temperature impact resistance and chemical resistance and a method for producing the same.

It is another object of the present invention to provide a branched polycarbonate-polysiloxane copolymer having improved flowability at high shear stress and temperature conditions and a method for producing the same.

The above and other objects of the present invention can be achieved by the present invention described below.

One aspect of the invention relates to branched polycarbonate-polysiloxane copolymers.

In one embodiment, the branched polycarbonate-polysiloxane copolymer is obtained from an aromatic dihydroxy compound, a carbonate precursor, a siloxane compound, and a branching agent, and the siloxane compound is represented by Formula 2 below, It is characterized in that the compound, or a combination thereof:

[Formula 2]

In Formula 2, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently substituted Or an unsubstituted C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or a C ₆ -C ₁₈ comprising oxygen or sulfur An arylene group, Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group, or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, X and Y Are each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₂₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are each independently an integer from 4 to 100;

[Formula 3]

In Formula 3, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently substituted or unsubstituted A C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group containing oxygen or sulfur or a C ₆ -C ₁₈ arylene group containing oxygen or sulfur, n is an integer from 4 to 100.

The branching agent is characterized in that represented by the following formula (1):

[Formula 1]

In Formula 1, Y ₁ is each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, m ₁ is an integer of 3 to 4 And n ₁ is an integer of 0 to 4, and R is a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group.

In embodiments, the branched polycarbonate-polysiloxane copolymer may include from about 0.1 to about 5% by weight of units derived from the branching agent represented by the formula (1).

The branched polycarbonate-polysiloxane copolymer may comprise from about 0.1 to about 20 weight percent of units derived from the siloxane compound.

The branched polycarbonate-polysiloxane copolymer may have a Si content of about 0.3 to about 10% by weight relative to the total polycarbonate-polysiloxane copolymer.

The branched polycarbonate-polysiloxane copolymer may have a branching degree of about 0.3 or more and less than about 1.0.

The mark-hew constant of the branched polycarbonate-polysiloxane copolymer may be at least about 0.50 and less than about 0.65.

Polycarbonate-polysiloxane copolymers according to another aspect of the present invention comprises a unit represented by the formula (2-1), a unit represented by the formula (3-1), or a combination thereof, the mark-Hink constant is about 0.50 And less than about 0.65:

[Formula 2-1]

In Formula 2-1, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently Substituted or unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group including oxygen or sulfur or C ₆ -containing oxygen or sulfur A C ₁₈ arylene group, Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group, or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, X And Y are each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are integers from 4 to 100, and * is Polycarbonate unit linkers;

[Formula 3-1]

In Formula 3-1, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently substituted or Unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or C ₆ -C ₁₈ aryl comprising oxygen or sulfur It is a rene group, n is an integer of 4-100, * is a polycarbonate unit coupling group.

Another aspect of the invention relates to a process for the preparation of branched polycarbonate-polysiloxane copolymers. The preparation method comprises the steps of mixing an aromatic dihydroxy compound and the branching agent represented by the formula (1); And reacting the siloxane compound with a carbonate precursor solution by adding the mixture to the mixture, wherein the siloxane compound is a compound represented by Formula 2, a compound represented by Formula 3, or a combination thereof. .

The present invention provides a branched polycarbonate-polysiloxane copolymer having excellent low temperature impact strength, high temperature fluidity, mechanical strength, chemical resistance, and the like, and a method of manufacturing the same.

Hereinafter, the present invention will be described in detail.

Branched polycarbonate-polysiloxane copolymers according to the present invention can be prepared by reacting aromatic dihydroxy compounds, carbonate precursors, siloxane compounds and branching agents.

In one embodiment, the branched polycarbonate-polysiloxane copolymer is a step of mixing an aromatic dihydroxy compound and a branching agent represented by the formula (1), and the reaction by adding a siloxane compound and a carbonate precursor solution to the mixture It may be prepared to include.

The aromatic dihydroxy compound used in the present invention may be represented by the following formula (7).

[Formula 7]

In Formula 7, A ₁ is a single bond, a substituted or unsubstituted C ₁ -C ₃₀ linear or branched alkylene group, a substituted or unsubstituted C ₂ -C ₅ alkenyl A cycloene group, a substituted or unsubstituted C ₂ -C ₅ alkylidene group, a substituted or unsubstituted C ₁ -C ₃₀ linear or branched haloalkylene group, a substituted or unsubstituted C ₅ -C ₆ cyclo Alkylene group, substituted or unsubstituted C ₅ -C ₆ cycloalkenylene group, substituted or unsubstituted C ₅ -C ₁₀ cycloalkylidene group, substituted or unsubstituted C ₆ -C ₃₀ arylene group, substituted Or an unsubstituted C ₁ -C ₂₀ linear or branched alkoxylene group, halogen acid ester group, carbonate ester group, CO, S, and SO ₂ , a linking group selected from the group consisting of R ₉ and R ₁₀ are each independently a substituted or an alkyl group of the unsubstituted C ₁ -C _30, or a substituted or unsubstituted C ₆ -C ₃₀ aryl group, n ₂ n ₃ are each independently an integer from 0 to 4.

In the present invention, the term "substituted" means that the hydrogen atom is a halogen group, C ₁ -C ₃₀ alkyl group, C ₁ -C ₃₀ haloalkyl group, C ₆ -C ₃₀ aryl group, C ₁ -C ₂₀ alkoxy group And a substituent selected from the group consisting of a combination thereof.

The branching agent used in the present invention may be represented by the following formula (1).

[Formula 1]

In Formula 1, Y ₁ is each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, m ₁ is an integer of 3 to 4 And n ₁ is an integer of 0 to 4, R is a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group.

In embodiments, the branched polycarbonate-polysiloxane copolymer may include about 0.1 to about 5 wt%, preferably about 0.5 to about 3 wt%, of units derived from the branching agent represented by Formula 1 above. It is possible to prevent the heterogeneous polymerization state due to the gelation and network structure in the above range, to optimize the branching of the branched polycarbonate-polysiloxane copolymer and to maintain a high impact.

The siloxane compound used in the present invention may be a compound represented by Formula 2, a compound represented by Formula 3, or a combination thereof.

[Formula 2]

In Formula 2, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently substituted Or an unsubstituted C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or a C ₆ -C ₁₈ comprising oxygen or sulfur An arylene group, Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group, or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, X and Y Are each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are each independently an integer of 4 to 100.

[Formula 3]

In Formula 3, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently substituted or unsubstituted A C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group containing oxygen or sulfur or a C ₆ -C ₁₈ arylene group containing oxygen or sulfur and n is an integer of 4-100.

For example, the siloxane compound represented by Chemical Formula 2 may be prepared by reacting a siloxane terminated with a hydride represented by Chemical Formula 4 with a phenol derivative represented by Chemical Formula 5 to synthesize a monohydroxysiloxane represented by Chemical Formula 6. It may be prepared by reacting the monohydroxysiloxane with a diene.

[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4 to 6, R ₁ to R ₄ , A, X, and m are as defined in Formula 2, D is a substituted or unsubstituted C ₁ -C ₁₀ alkylene group or substituted having a double bond at the terminal Or an unsubstituted C ₆ -C ₁₈ arylene group, or a C ₁ -C ₁₀ alkylene group or a C ₆ -C ₁₈ arylene group having -O- or -S- having a double bond at the terminal. Here, D of the phenol derivative may react with siloxane terminated with hydride to form A of monohydroxysiloxane. In addition, as the compounds represented by Formulas 4 to 6, two or more kinds of compounds having the same or different R ₁ to R ₄ , A, D, X, and m may be used, and R ₁ to R ₄ , A, Compounds represented by the formula (6), wherein X, m, etc. are the same or different from each other react with a diene, and R ₁ to R ₈ , A, B, X, Y, m, n, etc. of the siloxane compound represented by Formula 2 Can be represented.

Specific examples of the siloxane compound represented by Formula 2 may include, but are not limited to, the following compounds.

,

,

,

,

,

,

.

The branched polycarbonate-polysiloxane copolymer may comprise from about 0.1 to about 20 weight percent, preferably from about 0.5 to about 15 weight percent of units derived from the siloxane compound. In this range, the branched polycarbonate-polysiloxane copolymer can maintain transparency in particular.

Examples of the carbonate precursor used in the present invention include phosgene, triphosgene, diaryl carbonate, mixtures thereof, and the like.

The branched polycarbonate-polysiloxane copolymer according to the present invention includes a unit represented by the following Chemical Formula 2-1, a unit represented by the following Chemical Formula 3-1, or a combination thereof.

[Formula 2-1]

In Formula 2-1, R ₁ to R ₈ , A, B, Z, X, Y, n and m are the same as defined in Formula 2, and * is a polycarbonate unit linking group.

[Formula 3-1]

In Formula 3-1, R ₁ , R ₂ , A, B, and n are as defined in Formula 3, and * is a polycarbonate unit linking group.

The branched polycarbonate-polysiloxane copolymer of the present invention may have a Si content of about 0.3 to about 10% by weight, preferably about 0.8 to about 8% by weight relative to the total polycarbonate-polysiloxane copolymer. It is possible to maintain excellent transparency and high impact in the above range.

The branched polycarbonate-polysiloxane copolymer may have a branching degree of about 0.3 or more and less than about 1.0, preferably about 0.5 to about 0.8.

The mark-huke constant of the branched polycarbonate-polysiloxane copolymer may be from 0.50 to less than 0.65, preferably from about 0.55 to about 0.60.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, the following examples are provided to help the understanding of the present invention, and the scope of the present invention is not limited to the following examples. Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

EXAMPLE

Example 1

7 L of distilled water, 1.5 kg of bisphenol A, and 10.06 g of a branching agent represented by the following Chemical Formula 1-1 were added to a 20 L glass reactor, followed by stirring at room temperature. To this solution was added 2.1 kg of 50% NaOH solution at a rate of 60 mL per minute. After the temperature of the reaction solution was lowered to 25 ° C. or lower, 42 g of t-butylphenol (TBP) and 3.5 L of dichloromethane were added and stirred. After adding 150 g of the siloxane compound represented by the formula (2-2), a solution of 980 g of triphosphene in 3 L of dichloromethane was added at a rate of 42 mL per minute. After stirring for 3 hours, 9 g of triethylamine (TEA) was added and stirred for 2 hours, and then the organic layer was separated, washed with 0.1 N hydrochloric acid solution, washed three times with 15 L of distilled water, and then dichloromethane was removed. A polysiloxane copolymer was obtained.

[Formula 1-1]

[Formula 2-2]

Example 2

A branched polycarbonate-polysiloxane copolymer was obtained in the same manner as in Example 1 except that the amount of the branching agent represented by Chemical Formula 1-1 was increased from 10.06g to 20.13g.

Example 3

A branched polycarbonate-polysiloxane copolymer was obtained in the same manner as in Example 1 except that the siloxane compound represented by the following Formula 2-3 was applied instead of the siloxane compound represented by the above Formula 2-2.

[Formula 2-3]

(In Formula 2-3, n is 40.)

Comparative Example 1

A branched polycarbonate was obtained in the same manner as in Example 1 except that the siloxane compound was not used.

Comparative Example 2

A polycarbonate-polysiloxane copolymer was obtained in the same manner as in Example 1 except that no branching agent was used.

The physical properties of the polycarbonate-based resins of Examples 1 to 3 and Comparative Examples 1 to 2 were evaluated by the following methods, and the results are shown in Table 1:

Property measurement method

(1) Weight average molecular weight and number average molecular weight: It was measured based on PS standard using GPC (manufactured by ViscoTek) (unit: g / mol).

(2) Si content (% by weight): measured using a 300MHz Topspin NMR manufactured by Bruker.

(3) M-H (Mark-Hink) constant: It measured by GPC (ViscoTek company make) method. From the weight average molecular weight and the slope of Intrinsic Viscosity. In the case of the linear structure, the M-H constant is measured to be close to 0.7, and the higher the degree of branching, the smaller the M-H constant. In general, the M-H constant of the branched polycarbonate is less than 0.65.

(4) Impact resistance (kgfcm / cm): By ASTM D256 evaluation method. Notches were made on 1/8 "Izod specimens and evaluated at -30 ° C.

(5) Melt Index ratio (MIR): It is expressed as a ratio of Melt Index measured at 1.2 kg and 10 kg at 250 ° C. based on ASTM D 1238.

Table 1

	Example 1	Example 2	Example 3	Comparative Example 1	Comparative Example 2
Number average molecular weight (Mn)	8,400	9,700	8,900	9,900	8,700
Weight average molecular weight (Mw)	27,200	39,000	26,800	29,100	20,200
PDI	3.24	4.02	3.01	2.94	2.32
Si (% by weight)	2.67	2.65	2.61	-	2.75
Branching agent content (% by weight)	0.5	1.0	0.5	0.5	-
MH constant	0.584	0.515	0.590	0.616	0.668
1/8 "IZOD Impact Strength (-30 ℃)	60	62	65	14	63
MIR	15	18	14	13	10

As shown in Table 1, it can be seen that as the amount of branching agent increases, the M-H constant decreases to further branching. Comparative Example 1 was compared with Example 1 by adding only a branching agent without a siloxane, it can be seen that shows a similar level of M-H constant. Comparative Example 2 is a polycarbonate-polysiloxane copolymer without adding a branching agent, from which it can be seen that the M-H constant increases when no branching agent is added. It can be seen that the impact resistance was improved compared to Comparative Example 1, which is a branched polycarbonate without siloxane. In terms of high temperature fluidity, Examples 1 to 3 showed overall high MIR, in particular, Example 2, which had a high degree of branching, compared to Comparative Example 2, an unbranched polycarbonate-polysiloxane. It can be seen. From this, it can be seen that when the degree of branching of the branched polycarbonate-polysiloxane copolymer increases, the high temperature fluidity also increases.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (9)

1. A branched poly, obtained from an aromatic dihydroxy compound, a carbonate precursor, a siloxane compound and a branching agent, wherein the siloxane compound is a compound represented by the following formula (2), a compound represented by the following formula (3), or a combination thereof Carbonate-Polysiloxane Copolymers:

   [Formula 2]

   

   In Chemical Formula 2, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently substituted or Unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or C ₆ -C ₁₈ aryl comprising oxygen or sulfur Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, and X and Y are Each independently is a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are each independently an integer from 4 to 100;

   [Formula 3]

   

   In Formula 3, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently substituted or unsubstituted A C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group containing oxygen or sulfur or a C ₆ -C ₁₈ arylene group containing oxygen or sulfur , n is an integer from 4 to 100.
2. The branched polycarbonate-polysiloxane copolymer according to claim 1, wherein the branching agent is represented by the following Chemical Formula 1.

   [Formula 1]

   

   In Formula 1, Y ₁ is each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, m ₁ is an integer of 3 to 4 And n ₁ is an integer of 0 to 4, and R is a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group.
3. The branched polycarbonate-polysiloxane copolymer of claim 2, wherein the branched polycarbonate-polysiloxane copolymer comprises from about 0.1 to about 20 wt% of units derived from the branching agent represented by Formula 1 above.
4. The branched polycarbonate-polysiloxane copolymer of claim 1, wherein the branched polycarbonate-polysiloxane copolymer comprises from about 0.1 to about 20 weight percent of units derived from the siloxane compound.
5. The branched polycarbonate-polysiloxane copolymer of claim 1, wherein the branched polycarbonate-polysiloxane copolymer has a Si content of about 0.3 to about 10 weight percent relative to the total polycarbonate-polysiloxane copolymer.
6. The branched polycarbonate-polysiloxane copolymer of claim 1, wherein the branched polycarbonate-polysiloxane copolymer has a branching degree of at least about 0.3 and less than about 1.0.
7. The branched polycarbonate-polysiloxane copolymer of claim 1, wherein the mark-huke constant of the branched polycarbonate-polysiloxane copolymer is from about 0.50 to less than about 0.65.
8. A branched polycarbonate-polysiloxane comprising a unit represented by the following Chemical Formula 2-1, a unit represented by the following Chemical Formula 3-1, or a combination thereof, wherein the Mark-Hink constant is about 0.50 or more and less than about 0.65. Copolymer:

   [Formula 2-1]

   

   In Formula 2-1, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently Substituted or unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group including oxygen or sulfur or C ₆ -C including oxygen or sulfur _{18 is an} arylene group, Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group, or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, X and Each Y is independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are each independently an integer of 4 to 100, * Is a polycarbonate unit linker;

   [Formula 3-1]

   

   In Formula 3-1, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently a substituted or Unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or C ₆ -C ₁₈ aryl comprising oxygen or sulfur It is a rene group, n is an integer of 4-100, * is a polycarbonate unit coupling group.
9. Mixing an aromatic dihydroxy compound and a branching agent represented by Formula 1 below; And

   And reacting the siloxane compound with a carbonate precursor solution by adding the mixture to the mixture.

   The siloxane compound is a compound represented by the following formula (2), a compound represented by the formula (3), or a combination thereof, a method for producing a branched polycarbonate-polysiloxane copolymer:

   [Formula 1]

   

   In Formula 1, Y ₁ is each independently a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, m ₁ is an integer of 3 to 4 And n ₁ is an integer of 0 to 4, R is a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group;

   [Formula 2]

   

   In Chemical Formula 2, R ₁ to R ₈ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, and A and B are each independently substituted or Unsubstituted C ₁ -C ₁₀ alkylene group, substituted or unsubstituted C ₆ -C ₁₈ arylene group, C ₁ -C ₁₀ alkylene group comprising oxygen or sulfur or C ₆ -C ₁₈ aryl comprising oxygen or sulfur Z is a substituted or unsubstituted C ₁ -C ₁₈ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ cycloalkylene group or a substituted or unsubstituted C ₆ -C ₁₈ arylene group, and X and Y are Each independently is a hydrogen atom, a halogen atom, a C ₁ -C ₁₈ alkoxy group, a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₈ aryl group, n and m are each independently an integer from 4 to 100;

   [Formula 3]

   

   In Formula 3, R ₁ and R ₂ are each independently a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₆ -C ₁₈ aryl group, A and B are each independently substituted or unsubstituted A C ₁ -C ₁₀ alkylene group, a substituted or unsubstituted C ₆ -C ₁₈ arylene group, a C ₁ -C ₁₀ alkylene group containing oxygen or sulfur or a C ₆ -C ₁₈ arylene group containing oxygen or sulfur , n is an integer from 4 to 100.