KR100425981B1 - Flame-retardant polycarbonate-based plastic resin composition - Google Patents

Abstract

The present invention contains (A) 45 to 95% by weight of a thermoplastic polycarbonate resin containing no halogen, (B) 5 to 50% by weight of a rubber modified styrene containing graft copolymer resin containing no halogen, and (C) a halogen. Styrene-containing copolymer resin 0-30% by weight, (D) phosphate ester compound, (E) magnesium hydroxide, and (F) fluorinated polyolefin resin, wherein (A) + (B) + (C) (D) + (E) is 2 to 20 parts by weight, (F) is 0 to 2 parts by weight based on 100 parts by weight, and (D) + (E) to (D): (E) is 50:50 It relates to a polycarbonate-based thermoplastic resin composition having flame retardancy, characterized in that ~ 90:10.

Description

Polycarbonate-based thermoplastic resin composition having flame retardancy

Field of invention

The present invention relates to a polycarbonate-based thermoplastic resin composition having flame retardancy. More specifically, the present invention relates to a polycarbonate-based thermoplastic resin composition comprising a polycarbonate resin, a rubber-modified styrene-containing graft copolymer, a styrene-containing copolymer, a phosphate ester, magnesium hydroxide, and a fluorinated polyolefin resin.

Background of the Invention

Polycarbonate resins are excellent in transparency, mechanical strength and heat resistance, and are used in many applications such as electric and electronic products and automobile parts. However, polycarbonate resins themselves have disadvantages of low notch impact strength and poor workability. Therefore, in order to improve workability and notch impact strength, it is blended with other kinds of resins. For example, a mixture of polycarbonate resin and styrene resin is a resin mixture which maintains high notch impact strength and improves workability. Since the resin of this polycarbonate composition is usually applied to a large heat dissipating material such as a computer housing or other office equipment, it is essential that the resin should be flame retardant and maintain high mechanical strength.

Conventionally, halogen-based flame retardants have been used to impart flame retardancy to such resin compositions. However, when halogen-based flame retardants are used, the demand for resins containing no halogen-based flame retardants has been rapidly expanded due to the human hazards of gases generated during combustion. A technique for imparting flame retardancy without using a halogen-based flame retardant is currently the most common is to use a phosphate ester flame retardant.

However, the phosphate ester flame retardant has a problem that the heat resistance when used. U.S. Pat.Nos. 5,030,675 and 5,061,745 used polycarbonate resins, rubber modified styrene-containing graft copolymers, styrene-containing copolymers, monomolecular phosphate esters and fluorinated polyolefin-based resins. The heat resistance fall with the use of phosphate ester was remarkable.

On the other hand, in order to reduce the heat resistance decrease by the monomolecular phosphate ester, US Patent No. 5,204,394 discloses a resin composition using a phosphate ester oligomer having a degree of condensation of a polycarbonate resin and a styrene resin as a flame retardant have. However, even in this case, the heat resistance was only slightly higher than that of using the monomolecular phosphate ester.

In order to increase the heat resistance of polycarbonate-based resin compositions using phosphate esters as flame retardants, the present inventors use a mixture of phosphate ester and aluminum hydroxide in an appropriate ratio, thereby securing flame retardancy and heat resistance even if the amount of phosphate ester decreases. Has developed an excellent polycarbonate resin composition. However, in this case, there is still a problem in which silver occurs in the appearance at the injection temperature of about 250 ° C.

Therefore, the researchers found that by using magnesium hydroxide, which has a higher thermal decomposition temperature than aluminum hydroxide, in combination with phosphate ester, it is possible to prepare a resin composition which does not generate silver while maintaining existing physical properties.

It is an object of the present invention to provide a polycarbonate-based thermoplastic resin composition having no silver in appearance and having excellent flame retardancy.

Another object of the present invention is to provide a flame retardant polycarbonate-based thermoplastic resin composition excellent in heat resistance.

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

The polycarbonate-based thermoplastic resin composition of the present invention includes (A) polycarbonate resin, (B) rubber modified styrene-containing graft copolymer, (C) styrene-containing copolymer, (D) phosphate ester, (E) magnesium hydroxide, and (F) It consists of fluorinated polyolefin resin, The detailed description of each of these components is as follows.

(A) polycarbonate resin

The polycarbonate resin (A) of the present invention is an aromatic polycarbonate which does not contain a halogen and is produced by the reaction of a divalent phenol compound with phosgene or diester carbonate. The structure of the divalent phenolic compound is represented by the following formula (I):

In the formula (Ⅰ) A is a single bond, C ₁ ~C ₅ alkylene, C ₂ ~C cycloalkylidene of ₅ alkylidene, C ₅ ~C ₆ a, S or SO _2.

Examples of the dihydric phenol compound represented by formula (I) include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2'-bis (4-hydroxyphenyl) propane, and 1,1'- Bis (4-hydroxyphenyl) cyclohexane and the like. Bisphenols are preferable, and 2,2'-bis (4-hydroxyphenyl) propane, ie, bisphenol A is more preferable. Polycarbonate is prepared by reacting the divalent phenolic compound with phosgene on an interface or in a uniform phase. Polycarbonates having a specific molecular weight can be obtained by controlling the amount of monophenols such as phenol, paracresol, paraisooctylphenol and the like by using a chain terminator. The polycarbonate resin (A) of the present invention has a weight average molecular weight (M _W ) of 10,000 to 200,000, preferably 20,000 to 80,000. Meanwhile, the polycarbonate may be a homopolymer or a copolymer of a dihydric phenol compound.

The polycarbonate resin (A) together with the rubber modified styrene-containing graft copolymer (B) and / or the styrene-containing copolymer constitutes a base resin. Polycarbonate is used in the range of 45 to 95% by weight in the total base resin.

(B) Rubber Modified Styrene-Containing Graft Copolymer

The rubber-modified styrene-containing graft copolymer resin used in the present invention is 30 to 65% by weight of one or a mixture of styrene, α -methylstyrene, nuclear substituted styrene, and methylmethacrylate and acrylonitrile, methacryl Butadiene rubber, acrylic rubber, ethylene / propylene having a glass transition temperature of -10 ° C. Rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, butadiene / styrene rubber, polyisoprene, ethylene-propylene-diene monomer terpolymer (EPDM), polyorganosiloxane and polyalkyl (meth) acrylate composite rubber Or a copolymer grafted to 5 to 60% by weight of a mixture thereof. The graft copolymer resin may be prepared by a conventional polymerization method, but is preferably one synthesized by emulsion polymerization and bulk polymerization. Acrylonitrile / butadiene / styrene (ABS) resins in which acrylonitrile and styrene are grafted to butadiene rubber are widely used.

The rubber modified styrene-containing graft copolymer is used in the range of 5 to 50% by weight in the total base resin. The average size of the rubber particles in the preparation of the graft copolymer is in the range of 0.05 to 4㎛ considering the impact strength and appearance.

(C) styrene-containing copolymer

The styrenic-containing copolymer used in the present invention is 50 to 80% by weight of at least one of styrene, α -methylstyrene and nuclear substituted styrene, and acrylonitrile, methyl methacrylate, butyl acrylate, maleic hydride, And at least one of N-substituted maleimide consists of 20 to 50% by weight. As the styrene-containing copolymer resin, one produced by a conventional polymerization method can be used, and one synthesized by suspension polymerization or bulk polymerization is particularly suitable.

(D) phosphate ester

The phosphate ester used in the present invention is preferably commercially available resorcinol diphenyl phosphate (RDP), and is represented by the following structural formula (II):

In formula (II), Ar ¹ to Ar ⁴ are one or more mixtures of cresyl, phenyl, xylene, propylphenyl, butylphenyl, and bromine or chlorine substituent, R is arylene, and n is 0 From 5 to 5.

(E) magnesium hydroxide

Magnesium hydroxide used in the present invention is preferably magnesium hydroxide commercially available.

(F) fluorinated polyolefin resin

Fluorinated polyolefin resins used in the present invention are conventionally available resins such as polytetrafluoroethylene, polyvinylidene fluoride, copolymers of tetrafluoroethylene and vinylidene fluoride, and tetrafluoroethylene and hexafluoro There is a copolymer of ropropylene. These may be used independently from each other, or a mixture of two or more different from each other may be used.

The fluorinated polyolefin resin which can be preferably used in the present invention is polytetrafluoroethylene. Polytetrafluoroethylene having a particle size of 0.05 to 1,000 μ is suitable for mixing. The amount of fluorinated polyolefin resin used is 0 to 2.0 parts by weight based on 100 parts by weight of the base resin.

The thermoplastic resin composition of the present invention is mixed in a conventional mixer after adding an inorganic additive, a heat stabilizer, an antioxidant, a light stabilizer, a pigment and / or a dye according to each use. This mixture is prepared into a resin composition in pellet form through an extruder. At this time, the inorganic additives added may include asbestos, glass fibers, talc, and ceramics, which may be used in the range of 0 to 50 parts by weight based on 100 parts by weight of the base resin.

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

(A) polycarbonate resin, (B) rubber modified styrene-containing graft copolymer, (C) styrene-containing graft copolymer, (D) phosphoric acid used in Examples 1 to 3 and Comparative Examples 1 to 3 below The specifications of ester, (E) magnesium hydroxide, and (F) fluorinated polyolefin resin are as follows.

(A) polycarbonate resin

Bisphenol A type polycarbonate having a weight average molecular weight (M _W ) of the polycarbonate resin is 10,000 to 200,000, preferably 20,000 to 80,000.

(B) Rubber modified styrene-containing graft copolymer (g-ABS)

Butadiene rubber latex was added so that the content of butadiene was 45 parts by weight based on the total monomer, 1.0 parts by weight of potassium oleate, 1.0 parts by weight of urea peroxide, 0.4 parts by weight of styrene, 14 parts by weight of acrylonitrile, and 150 parts by weight of deionized water. By weight, 0.3 parts by weight of mercaptan-based chain transfer agent was added to maintain the reaction at 75 ℃ for 5 hours to prepare a g-ABS latex. The resulting polymer latex was added to 1% sulfuric acid solution and dried after coagulation to prepare a graft copolymer resin in powder form.

(C) Styrene-containing copolymer resin (SAN)

A SAN copolymer resin was prepared by suspension polymerization by adding 0.2 parts by weight of azobisisobutyronitrile and 0.5 parts by weight of tricalcium phosphate, which are necessary additives to a mixture of 70 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 120 parts by weight of deionized water. . The copolymer was washed with water, dehydrated and dried to obtain a SAN copolymer resin in powder form.

(D) phosphate ester

Commercially available RDP was used.

(E-1) magnesium hydroxide

Commercially available magnesium hydroxide was used.

(E-2) Aluminum Hydroxide

Aluminum hydroxide, Aldrich, USA was used.

(F) fluorinated polyolefin resin

Polytetrafluoroethylene having an average particle size of 10 to 50 µm was used.

Table 1 shows the composition and measured physical properties of each component used in Examples 1-3 and Comparative Examples 1-3. Examples 1-3 are resin compositions used by mixing phosphate ester and magnesium hydroxide in a suitable ratio.

As shown in Table 1, each component was mixed and the antioxidant and heat stabilizer were added, mixed in a conventional mixer, and then introduced into a twin screw extruder having a L / D of 29 and ￠ = 45 mm. The mixture was prepared into a resin composition in pellet form through an extruder, and a specimen was prepared at an injection temperature of 250 ° C., and then left at 23 ° C. and a relative humidity of 50% for 40 hours to measure physical properties.

Property measurement

(1) Flame retardancy: measured according to the UL94 method.

(2) Heat resistance: It measured by ASTM method.

(3) Silver degree: Silver retention was observed after 10 minutes at 250 ° C using a pin-point gate mold.

As shown in Table 1, Examples 1 to 3 according to the present invention did not generate silver as compared to Comparative Examples 1 to 3 was able to prepare a resin composition excellent in appearance.

The present invention does not generate silver in appearance, and has an effect of providing a polycarbonate-based thermoplastic resin composition having excellent heat resistance and flame retardancy.

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 (5)

45 to 95% by weight of (A) halogen-free thermoplastic polycarbonate resin, (B) 5 to 50% by weight of rubber-modified styrene-containing graft copolymer resin (H) without halogen, and (C) free of halogen 100 parts by weight of a base resin composed of 0 to 30% by weight of a styrene-containing copolymer resin; (D) 2 to 20 parts by weight of a phosphate ester compound and (E) magnesium hydroxide; And 0 to 2 parts by weight of (F) fluorinated polyolefin resin; Polycarbonate-based thermoplastic resin composition having a flame retardance, characterized in that consisting of. The polycarbonate-based thermoplastic resin composition having flame retardancy according to claim 1, wherein the phosphate ester compound (D) and magnesium hydroxide (E) are mixed in a weight ratio of 50:50 to 90:10. The polycarbonate-based thermoplastic resin composition having flame retardancy according to claim 1, wherein the phosphate ester compound is represented by the following structural formula (II): In formula (II), Ar ¹ to Ar ⁴ are one or more mixtures of cresyl, phenyl, xylene, propylphenyl, butylphenyl, and bromine or chlorine substituent, R is arylene, and n is 0 Number from 5 to 5. The method of claim 1, wherein the fluorinated polyolefin resin (F) is polytetrafluoroethylene, polyvinylidene fluoride, a copolymer of tetrafluoroethylene and hexafluoropropylene, and tetrafluoroethylene and hexafluoropropylene. Polycarbonate-based thermoplastic resin composition having a flame retardancy, characterized in that it is selected from the group consisting of a copolymer of. The polycarbonate-based thermoplastic resin composition of claim 1, wherein the resin composition further comprises an inorganic additive, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, and / or a dye.