KR100833957B1 - Polycarbonate resin composition with good impact resistance and chemical resistance - Google Patents

Abstract

A polycarbonate resin composition, a pellet obtained by extruding the composition, and an external material for electric or electronic products obtained by injection molding the composition are provided to improve impact resistance and chemical resistance. A polycarbonate resin composition comprises 100 parts by weight of a thermoplastic polycarbonate resin; and 0.1-10 parts by weight of a phenyl-substituted siloxane copolymer having a kinematic viscosity of 300-1,000 mm^2/s at 25 deg.C represented by the formula II, wherein R1 is a methyl group or a phenyl group; R2 is a methyl group, a phenyl group, a hydroxyl group, a methoxy group, a phenoxy group or a vinyl group; and n and m represent the number of repeating units.

Description

Polycarbonate Resin Composition with Good Impact Resistance and Chemical Resistance

Field of invention

The present invention relates to a polycarbonate resin composition excellent in impact resistance and chemical resistance. More specifically, the present invention relates to a polycarbonate resin composition comprising a polycarbonate resin and a phenyl group substituted siloxane copolymer having a specific dynamic viscosity.

Background of the Invention

Polycarbonate resins are used as engineering plastics because of their excellent impact resistance, flame retardancy, dimensional stability, and excellent heat resistance. However, polycarbonate resin is not easy to be applied to parts requiring precision because the fluidity is very low compared to the general thermoplastic resin. In addition, when the working temperature is increased for smooth molding of the polycarbonate resin composition, there is a problem in that physical properties decrease due to thermal decomposition of the impact modifier and the resin. In addition, when the injection molded article is used as an exterior material, the dilution solvent penetrates into the polycarbonate resin during the coating process exposed to the dilute solution of the paint, thereby deteriorating mechanical properties and impact resistance.

Thus, research has been conducted to prevent the phenomenon that the impact strength of the polycarbonate resin capable of thin-film injection molding is lowered. Conventionally, a core-shell type impact modifier has been used in which a rubber such as polybutadiene, an acrylate, an acrylate-siloxane copolymer is used as a core structure, and a shell structure is formed from a vinyl monomer.

By the said method, the fall of impact strength can be prevented to some extent. However, in this case, the fluidity of the resin is lowered, and mechanical properties such as tensile strength and flexural strength and heat resistance are lowered. In addition, when the injection at a high temperature to enable thin film molding there is a problem that discoloration due to rubber modification occurs, decomposition gas is generated to reduce the appearance characteristics.

In order to overcome the disadvantages of the core-shell impact modifiers, a method of introducing an organosiloxane polymer into a polycarbonate has been developed. Japanese Patent Laid-Open No. 55-18406, Japanese Patent Laid-Open No. 55-18407, Japanese Patent Laid-Open No. 60-88064 and Japanese Patent Laid-Open No. 5-86278 describe this. However, in the above method, when the content of the organosiloxane polymer is increased to a certain level or more in order to prevent a decrease in the impact strength, the impact strength of the polycarbonate resin appears rather, and the silver streak is formed on the surface of the molded part during high temperature injection. ) Is a problem that occurs.

In addition, in order to improve chemical resistance, a method of improving the chemical resistance of materials by blending polymers with relatively slow penetration of chemicals has been studied. However, this method can improve the chemical resistance but has a problem that the impact resistance is lowered.

U.S. Patent No. 3,218,372 discloses a resin composition in which polyalkylene terephthalate is mixed with a polycarbonate resin to lower melt viscosity and improve ductility than polyalkylene terephthalate. However, this method has a problem in that the compatibility between the two resins is poor and opaque and the impact strength is lowered.

U.S. Patent 4,391,954 discloses resin compositions consisting of polycarbonates and copolyesters prepared from mixtures of isophthalic acid, terephthalic acid and 1,4-cyclohexanedimethanol. However, even this resin composition cannot obtain sufficient impact strength.

U.S. Patent No. 4,634,737 discloses copolymerized polycarbonates having 25 to 90 mole percent ester bonds and copolyester and olefin acrylate copolymers prepared from isophthalic acid, terephthalic acid, ethylene glycol and 1,4-cyclhexanedimethanol The resin composition is disclosed. However, these compositions become opaque and do not obtain sufficient impact strength.

U.S. Patent 4,188,314 discloses sheet moldings comprising polycarbonate and copolyesters derived from isophthalic acid, terephthalic acid and 1,4-cyclohexanedimethanol and having improved chemical resistance, but in this way Not enough impact strength can be obtained.

The present inventors have studied and researched to solve the problems of the prior art, the introduction of a phenyl-substituted siloxane copolymer having a specific dynamic viscosity into the polycarbonate resin, the impact resistance and chemical resistance without lowering the mechanical properties of the polycarbonate inherent It is found that the present invention can be improved, and the polycarbonate resin composition of the present invention has been developed.

An object of the present invention is to provide a polycarbonate resin composition excellent in impact resistance.

Another object of the present invention is to provide a polycarbonate resin composition having excellent impact resistance and excellent chemical resistance.

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

Summary of the Invention

Polycarbonate resin composition excellent in impact resistance and chemical resistance according to the present invention (A) 100 parts by weight of a thermoplastic polycarbonate resin; And (B) kinematic viscosity at 25 ° C. It is characterized by consisting of 0.1 to 10 parts by weight of a phenyl group substituted siloxane copolymer represented by the following formula (II) of 300 to 1000 mm ² / s:

[Formula II]

Wherein R ₁ is a methyl or phenyl group, R ₂ is a methyl, phenyl, hydroxy, methoxy, phenoxy or vinyl group, n and m are integers indicating the number of repeating units.

Hereinafter, each component of the polycarbonate resin composition of this invention is demonstrated in detail below.

Detailed Description of the Invention

The polycarbonate resin composition of the present invention comprises (A) a thermoplastic polycarbonate resin and (B) a phenyl group substituted siloxane copolymer having a dynamic viscosity of 300 to 1000 mm ² / s at 25 ° C.

(A) polycarbonate resin

The polycarbonate resin according to the present invention is produced by reacting diphenols represented by the following general formula (I) with phosgene, halogen formate or diester carbonate.

[Formula I]

Wherein A represents a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cyclo alkylidene, -S- or -SO _2- .

Examples of the diphenol represented by the formula (I) include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, and 2,4-bis- (4 -Hydroxyphenyl) -2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 2,2-bis- (3-chloro-4-hydroxyphenyl) -propane, 2, 2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane and the like.

2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 1,1-bis in the specific example of the said diphenol Preference is given to using-(4-hydroxyphenyl) -cyclohexane, most preferably 2,2-bis- (4-hydroxyphenyl) -propane, also called bisphenol-A.

The polycarbonate resin of the present invention preferably has a weight average molecular weight (Mw) in the range of 10,000 to 200,000, and most preferably 15,000 to 80,000.

The polycarbonate resin may be a branched chain, preferably 0.05 to 2 mol% of tri- or more polyfunctional compounds, such as trivalent or more, based on the total amount of diphenols used in the polymerization. It can manufacture by adding the compound which has a phenol group.

As the polycarbonate used in the preparation of the resin composition of the present invention, all types of homo polycarbonates, copolycarbonates or blends thereof may be used.

In addition, the polycarbonate may be used in part or in whole by an aromatic polyester-carbonate resin obtained by polymerization in the presence of an ester precursor, such as a bifunctional carboxylic acid.

(B) dynamic viscosity at 25 Phenyl-substituted siloxane copolymers of 300 to 1000 mm ² / s

The phenyl group substituted siloxane copolymer used for preparing the resin composition of the present invention may be represented by the following general formula (II).

[Formula II]

Wherein R ₁ is a methyl or phenyl group, R ₂ is a methyl, phenyl, hydroxy, methoxy, phenoxy or vinyl group, n and m are integers indicating the number of repeating units.

The phenyl-substituted siloxane copolymer may be used in a form in which copolymers having different n and m values are mixed, and in this case, the average n: m ratio is preferably in the range of 9: 1 to 3: 7.

The dynamic viscosity of the phenyl group substituted siloxane copolymer used for preparing the resin composition of the present invention is 25 ℃ It can use 100-1000 mm <^2> / S, It is more preferable to use 300-1000 mm <^2> / S, Most preferably 300-800 mm <^2> / S. When the dynamic viscosity is out of the 300 to 1000 mm ² / S range, the effect of improving the impact resistance and chemical resistance can be reduced.

Examples of the phenyl group-substituted siloxane copolymer include poly (methylphenyl) siloxane in which R ₁ and R ₂ are both methyl groups; Poly (diphenyl) siloxane in which both R ₁ and R ₂ are substituted with a phenyl group; There is a copolymer of dimethylsiloxane in which both R ₁ and R ₂ are substituted with methyl groups and diphenylsiloxane in which both R ₁ and R ₂ are substituted with phenyl groups. Of these, poly (methylphenyl) siloxane polymers are preferred.

The polycarbonate resin composition has a 1/8 "Notch Izod impact strength of 88-98 Kgf · cm / cm, measured according to ASTM D256 standard, and the specimen was used as a thinner for undercoat of mobile resin of DAIHAN BEE CHEMICAL Co., Ltd. Falling impact strength measured by ASTM D3209 standard after immersion in T-276 can be 3000 ~ 3700N.

In addition to the above components, the polycarbonate resin composition of the present invention may be an antioxidant, an impact modifier, a lubricant, a mold release agent, a nucleating agent, an antistatic agent, a reinforcing agent, an inorganic additive, an ultraviolet stabilizer, a fluorescent brightener, a pigment or a dye, and the like. General additives may be included. The amount of the additive added is in the range of 0 to 60 parts by weight, preferably 1 to 40 parts by weight based on 100 parts by weight of the above-mentioned (A) polycarbonate resin.

The resin composition of this invention can be manufactured by a well-known method. For example, the components of the present invention and other additives may be mixed simultaneously, then melt extruded in an extruder and prepared in pellet form.

The polycarbonate resin composition according to the present invention is excellent in impact resistance and chemical resistance, and is useful for producing internal and external injection molding products for electrical and electronic products requiring the above physical properties. In particular, it is suitable for injection molding materials for exterior materials such as televisions, washing machines, computers, audio, video, CD players, mobile phones, telephones, and battery cases.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Specific specifications of each component used in the Examples and Comparative Examples of the present invention are as follows.

(A) polycarbonate resin

In Examples and Comparative Examples of the present invention, Bisphenol-A polycarbonate having a weight average molecular weight of 25,000 g / mol, Markrolon ^® 2800 of BAYER, Germany was used.

(B) organosiloxane polymer

(B-1) Phenyl-substituted siloxane copolymer having a viscosity within the scope of the present invention

The phenyl group substituted siloxane copolymer used in the embodiment of the present invention used TSF-433 polymethylphenylsiloxane oil of GE-Toshiba Silicones having a kinematic viscosity of 450 mm ² / S at 25 ° C.

(B-2) Phenyl-substituted siloxane copolymer having a viscosity outside the scope of the present invention

The phenyl group substituted siloxane copolymer used in the comparative example of the present invention used SF-1550 polymethylphenylsiloxane oil of GE-Toshiba Silicones having a dynamic viscosity of 20 mm ² / S at 25 ° C.

(B-3) polydimethylsiloxane having a viscosity within the scope of the present invention

The polydimethylsiloxane used in the comparative example of the present invention used DM-FLUID-500SC polydimethylsiloxane oil of Japan Shin-Etsu Silicones having a dynamic viscosity of 500 mm ² / S at 25 ° C.

(B-4) Polydimethylsiloxane Having Viscosity Outside the Invention

The polyester used in the Comparative Examples of the present invention, polydimethylsiloxane is the dynamic viscosity at 25 ℃ 50 mm ² / S of Dow-Corning's 200 ^® Fluid. 50 Cst polydimethylsiloxane oil was used.

Example  1 and 2 and Comparative Example  1 to 5

The antioxidants and heat stabilizers were added to each component of the contents shown in Table 1, mixed in a conventional mixer, extruded using a twin screw extruder having L / D = 35 and Φ = 45 mm, and the extrudate was pelleted. Prepared. Thereafter, the pellets were dried in a hot air dryer at 120 ° C. for at least 4 hours, and then specimens for physical property measurement and appearance evaluation at the injection temperature of 320 ° C. were prepared using a 10 oz injection machine. After these specimens were allowed to stand at 23 ° C. and 50% relative humidity for 48 hours, the physical properties were evaluated in the following manner according to ASTM standards, and the results are shown in Table 1 below.

Property evaluation method

(1) Notched Izod impact strength: 1/8 "test piece was measured according to ASTM D256 standard.

(2) Fall impact strength: 3.2 mm thick specimens were evaluated at maximum load in accordance with ASTM D3209.

(3) Chemical resistance: Falling before and after immersion of specimens 10 cm wide and 3.2 mm thick in T-276 used as a thinner for DAIHAN BEE CHEMICAL's mobile resin. Impact strength was compared. The plate specimen was immersed in the diluent for 1 minute and dried for a specific time, and then the fall load was measured by dropping a 5 kg weight at 1 m height.

From the results in Table 1, in Examples 1 to 2 using (A) a phenyl group-substituted siloxane copolymer having a specific dynamic viscosity in a certain ratio in the polycarbonate resin, it was excellent in impact resistance and also excellent in chemical resistance. Able to know. However, in the case of Comparative Example 1 using the (B) phenyl group substituted siloxane copolymer outside the dynamic viscosity range of the present invention and Comparative Examples 2 and 3 without using the (B) phenyl group substituted siloxane copolymer of the present invention, a diluent It can be seen that the impact strength drops significantly after thinner immersion. In addition, in the case of Comparative Example 4 containing no organosiloxane copolymer and Comparative Example 5 using an amount of the (B) phenyl group substituted siloxane copolymer outside the scope of the present invention, it was found that both impact resistance and chemical resistance were reduced. Can be.

This invention has the effect of providing the polycarbonate resin composition excellent in impact resistance and chemical resistance. The resin composition is useful for producing an exterior material for electrical and electronic products, which can obtain an excellent injection product without lowering the impact strength and which requires impact resistance and chemical resistance.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (8)

(A) 100 parts by weight of thermoplastic polycarbonate resin; And (B) 0.1 to 10 parts by weight of a phenyl group substituted siloxane copolymer represented by the following formula (II) having a kinematic viscosity of 300 to 1000 mm ² / s at 25 ° C; Polycarbonate resin composition excellent in impact resistance and chemical resistance, characterized in that consisting of: [Formula II]

Wherein R ₁ is a methyl or phenyl group, R ₂ is a methyl, phenyl, hydroxy, methoxy, phenoxy or vinyl group, n and m are integers indicating the number of repeating units. The polycarbonate resin composition according to claim 1, wherein the phenyl group-substituted siloxane copolymer (B) is a poly (methylphenyl) siloxane in which R ₁ and R ₂ are both methyl groups. The polycarbonate resin composition according to claim 1, wherein the (B) phenyl group substituted siloxane copolymer is a poly (diphenyl) siloxane in which both R ₁ and R ₂ are substituted with a phenyl group. The phenyl group-substituted siloxane copolymer according to claim 1, wherein the phenyl group-substituted siloxane copolymer is a copolymer of dimethylsiloxane in which both R ₁ and R ₂ are substituted with a methyl group, and diphenylsiloxane in which both R ₁ and R ₂ are substituted with a phenyl group. Polycarbonate resin composition. The polycarbonate resin composition according to claim 1, wherein the ratio of the average n and m values of the (B) phenyl group substituted siloxane copolymer is in the range of 9: 1 to 3: 7. According to claim 1, wherein the antioxidant composition, antioxidants, impact modifiers, lubricants, mold release agents, nucleating agents, antistatic agents, reinforcing agents, inorganic additives, UV stabilizers, fluorescent brighteners, pigments or dyes and mixtures thereof in an amount of 60 parts by weight or less Polycarbonate thermoplastic resin composition, characterized in that it further comprises. The pellet which extruded the polycarbonate resin composition of any one of Claims 1-6. The exterior material of the electrical / electronic product which injected the composition of any one of Claims 1-6.