KR20040003563A - Flameproof Thermoplastic Resin Composition - Google Patents

Abstract

PURPOSE: A flame retardant thermoplastic resin composition is provided, to improve the impact strength and the heat resistance with using a small amount of a flame retardant. CONSTITUTION: The thermoplastic resin composition comprises (A) 40-90 parts by weight of a styrene-based resin comprising (a1) 10-60 wt% of the styrene-containing graft copolymer resin prepared by graft polymerizing 10-60 wt% of a rubber component and (a2) 40-90 wt% of a styrene-acrylonitrile copolymer resin whose acrylonitrile content is 0.5-10 wt%, and 0-20 wt% of a rubber component; (B) 5-60 parts by weight of a polyphenylene ether resin; and (C) 2-30 parts by weight of a cyclic alkyl phosphonic acid compound based on 100 parts by weight of (A)+(B). Preferably the cyclic alkyl phosphonic acid compound is represented by the formula 1, wherein R1 and R2 are independently an alkyl group of C1-C4; and x is 0 or 1.

Description

Flameproof Thermoplastic Resin Composition

Field of invention

The present invention relates to a flame retardant thermoplastic resin composition. More specifically, the present invention relates to a flame retardant thermoplastic resin composition comprising a rubber-modified styrene resin, a polyphenylene ether resin, and a cyclic alkyl phosphonic acid having a specific acrylonitrile content.

Background of the Invention

Polyphenylene ether resin has excellent heat resistance, mechanical strength, and numerical stability, and is widely used in various industrial fields such as interior and exterior materials of automobile parts and electronic products. Since polyphenylene ether resins are difficult to process alone, they are usually used in combination with a polystyrene resin having good compatibility.

However, the blend of the polyphenylene ether resin and the polystyrene resin has a problem in that the impact strength is lowered while improving processability. Therefore, in order to compensate for this, there is a method of improving the impact strength by applying a rubber-reinforced polystyrene resin including rubber, but this method has a disadvantage in that appearance characteristics such as gloss and moldability deteriorate.

The present inventors have found that when blending a rubber-modified styrene resin and a polyphenylene ether resin having a specific acrylonitrile content, the resin composition has excellent gloss, impact strength and moldability (Application No. 2002- 22864). However, since such a resin composition has a disadvantage in that it is easily burned, flame retardancy is required for use in electric, electronic products or office equipment that generates heat during use such as a monitor or a fax machine.

The most widely known flame retardant method is to impart flame retardancy by applying a halogen compound and an antimony compound to the resin in combination. However, halogen-containing compounds can damage the mold and have a fatal effect on the human body by the hydrogen halide gas generated during processing. In addition, since polybrominated diphenyl ethers, which are mainly halogen-based flame retardants, are highly likely to generate very toxic gases such as dioxins and furans during combustion, attention has been focused on flame-retardant methods that do not apply halogen-based compounds.

U.S. Patent No. 3,639,506 discloses a flame retardant resin using triphenyl phosphate (TPP), an aromatic phosphate ester, as a flame retardant in polyphenylene ether resins and styrene resins. However, the resin has a disadvantage in that the flame resistance is achieved but the heat resistance is lowered by TPP, and a halogen-based compound is used to overcome this problem.

U.S. Patent No. 3,883,613 discloses that it is effective to use trimethyl phosphate as a flame retardant in polyphenylene ether resins and styrene resins in order to solve the above problems.

In addition, U.S. Patent No. 4,526,917 found that when TPP and trimethyl phosphate are used together, the flame retardancy is improved more than when each is applied alone.

However, since such aromatic phosphate esters have a low phosphorus content of 10% or less, there is still a disadvantage that a large amount of flame retardant must be used to achieve flame retardancy.

U.S. Patent Nos. 3,789,091 and 3,849,368 disclose various cyclic phosphonic acid compounds as flame retardants of homopolymers such as polyethylene terephthalate, PAN, polyurethane, polystyrene, nylon, but with a specific acrylonitrile content. There is no technical mention of improving the flame retardancy and heat resistance when applied to modified styrene resin and phenylene ether resin blends.

Therefore, in order to overcome the above problems, the present inventors use a cyclic alkyl phosphonic acid compound as a flame retardant, based on a blend of a rubber-modified styrene-based resin and a polyphenylene ether resin having a specific acrylonitrile content. By doing so, not only excellent flame retardancy can be ensured even when a small amount of flame retardant is used, but it has also led to development of a flame retardant thermoplastic resin composition having no deterioration in physical properties or heat resistance.

An object of the present invention is to provide a flame retardant thermoplastic resin composition having a good flame retardant effect even using a small amount of flame retardant.

Another object of the present invention is to provide a flame retardant thermoplastic resin composition excellent in impact strength and heat resistance.

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

Hereinafter, the content of the present invention will be described in detail.

The thermoplastic resin composition of the present invention (A) 40 to 95 parts by weight of rubber-modified styrene resin; (B) 5 to 60 parts by weight of polyphenylene ether resin; And (C) 2 to 30 parts by weight of the cyclic alkyl phosphonic acid compound, optionally 0 to 20 parts by weight of (D) aromatic phosphoric acid ester may be further added. Detailed description of each of these components is as follows.

(A) Rubber modified styrene resin

Rubber modified resin refers to a polymer in which a rubber polymer is dispersed in a particle form in a matrix (continuous phase) made of a vinyl-aromatic polymer, and an aromatic vinyl monomer and a vinyl monomer copolymerizable therewith in the presence of a rubber polymer. It is prepared by adding and polymerizing. Such rubber-modified styrene resins can be produced by known polymerization methods such as emulsion polymerization, suspension polymerization, and bulk polymerization, and are usually produced by mixing and extruding graft copolymer resin and copolymer resin. In the case of the bulk polymerization, the rubber-modified styrene resin is produced by only one step reaction process without separately preparing the graft copolymer resin and the copolymer resin. In any of the above cases, the rubber content in the final rubber-modified styrene resin component is preferably 5 to 30 parts by weight based on the entire base resin.

Examples of such resins include acrylonitrile-butadiene-styrene copolymer resins (ABS), acrylonitrile-acrylic rubber-styrene copolymer resins (AAS), acrylonitrile-ethylenepropylene rubber-styrene copolymer resins, and the like. .

Examples of the above resin can be applied to the graft resin alone or in combination of the graft copolymer resin and the copolymer resin, and is preferably blended in consideration of their compatibility.

Rubber-modified styrene resin of the present invention (A) are (a ₁₎ 10 to 60 parts by weight of the rubber component and the acrylonitrile content of 0.5 to 10% by weight styrene-acrylonitrile copolymer resin, 90-40 parts by weight of graft polymerizing a styrene-containing graft copolymer resin prepared by 10 to 60 parts by weight of (a ₂₎ made of styrene-based resin, 90-40 parts by weight of a rubber component comprising 0 to 20% by weight.

(a ₁ ) Styrene-containing graft copolymer resin

Examples of the rubber used for the graft copolymer resin include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene), saturated rubbers hydrogenated with the diene rubber, isoprene rubber, And acrylic rubbers such as chloroprene rubber and butyl polyacrylate, and ethylene-propylene-diene monomer terpolymer (EPDM). Among these, diene rubber is particularly preferable. More preferably butadiene rubber is suitable.

The content of rubber is suitably 10 to 60 parts by weight in the weight of the graft copolymer resin.

As the aromatic vinyl monomer in the graft polymerizable monomer mixture, styrene, α-methyl styrene, p-methyl styrene, and the like may be added, of which styrene is most preferable, and a monomer copolymerizable with the aromatic vinyl monomer may be added thereto. Apply by introducing one or more. Preferable monomers include vinyl cyanide compounds such as acrylonitrile and unsaturated nitrile compounds such as methacrylonitrile.

The weight ratio of rubber in the graft copolymer as a whole component is 10 to 60 parts by weight, the component of the monomer grafted to the rubber is 90 to 99.5 parts by weight of an aromatic vinyl monomer such as styrene, unsaturated nitrile monomer Is applied by graft copolymerization by adding 0.5 to 10 parts by weight. Further, in order to impart properties such as workability and heat resistance, monomers such as acrylic acid, methacrylic acid, maleic anhydride and N-substituted maleimide can be added and graft polymerization. The amount added may be 0 to 40 parts by weight based on the graft resin as a whole.

In consideration of the impact strength and appearance in preparing the graft copolymer, the average size of the rubber particles is suitably in the range of 0.1 to 0.5 μm.

(a ₂ ) Styrene-based resin

The styrene-based resin may be prepared using a bulk polymerization, suspension polymerization, emulsion polymerization, or a mixture thereof, and will be described as an example of the bulk polymerization among these polymerization methods. That is, one type selected from aromatic monoalkenyl monomers, alkyl ester monomers of acrylic acid or methacrylic acid with respect to 0 to 20 parts by weight of rubber selected from butadiene rubbers, isoprene rubbers, copolymers of butadiene and styrene or alkyl acrylate rubbers. Alternatively, the resin may be prepared by adding 80 to 100 parts by weight of one or more monomers and bulk polymerization using one or more initiators selected from benzoyl peroxide, t-butyl hydroperoxide, acetyl peroxide, and cumene hydroperoxide. have.

The resin may be used alone or mixed with each other, a resin having a rubber content of 0 and a resin containing a rubber content.

In the rubber-modified styrene resin (A), the styrene-containing graft copolymer resin (a ₁ ) is 10 to 60 parts by weight and the styrene resin (a ₂ ) is 40 to 90 parts by weight.

(B) polyphenylene ether resin

Rubber-reinforced styrenic resins are used as the base resin by adding polyphenylene ether resins because of their low flame retardancy and poor heat resistance. Such compounds include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2,6-dipropyl-1, 4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2-ethyl -6-propyl-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6-dimethyl-1,4-phenylene) ether and poly Copolymer of (2,3,6-trimethyl-1,4-phenylene) ether and poly (2,6-dimethyl-1,4-phenylene) ether and poly (2,3,5-triethyl- Copolymers of 1,4-phenylene) ether. Preferably a copolymer of poly (2,6-dimethyl-1,4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether and poly (2,6-dimethyl- 1,4-phenylene) ether is used, of which poly (2,6-dimethyl-1,4-phenylene) ether is most preferred.

Although the polymerization degree of polyphenylene ether is not specifically limited, It is preferable that intrinsic viscosity measured in 25 degreeC chloroform solvent is 0.2-0.8 in consideration of the thermal stability and workability of a resin composition.

(C) cyclic alkyl phosphonic acid compounds

The cyclic alkyl phosphonic acid compound of the present invention is represented by the following formula (1).

[Formula 1]

Wherein R ₁ and R ₂ are each independently an alkyl group of C _1-4 and x is 0 or 1.

Compounds corresponding to the formula 1 include methyl-bis (5-ethyl-2-methyl-1,3,2, -dioxaphosphorin-5yl) methyl methyl phosphonic acid ester P oxide, methyl-bis ( 5-ethyl-2-methyl-1,3,2, -dioxaphosphorinan-5yl) phosphonic acid ester P, P'-dioxide.

In the present invention, the cyclic alkyl phosphonic acid compound (C) is added in an amount of 2 to 30 parts by weight based on 100 parts by weight of the base resin consisting of (A) + (B). When the cyclic alkyl phosphonic acid compound (C) is added in an amount less than 2 parts by weight, the effect of increasing the flame retardancy is insignificant.

(D) Aromatic Phosphate Ester Compounds

The aromatic phosphate ester compound of the present invention is represented by the following formula (2).

[Formula 2]

Wherein R ₃ , R ₄ and R ₅ are each independently hydrogen or an alkyl group of C _1-4 ; X is a C _6-20 aryl group which is substituted with a C _6-20 aryl group or an alkyl group and is derived from a dialcohol of resorcinol, hydroquinol or bisphenol-A. In addition, the range of n is 0-4.

Examples of the compound represented by Chemical Formula 2 include triphenyl phosphate, tricresyl phosphate, trigylenyl phosphate, tri (2,6-dimethylphenyl) phosphate, and tri (2,4,6-trimethylphenyl) when n is 0. Phosphate, tri (2,4-dibutylbutylphenyl) phosphate, tri (2,6-dibutylbutylphenyl) phosphate, and the like, when n is 1, resorcinol bis (diphenyl) phosphate, resorcinol Bis (2,6-dimethylphenyl) phosphate, resorcinolbis (2,4-dibutylbutyl) phosphate, hydroquinolbis (2,6-dimethylphenyl) phosphate, hydroquinolbis (2,4-diary) Butylphenyl) phosphate etc. are typical examples. These aromatic phosphoric acid ester compounds may be applied alone or may be applied to each mixture.

In the thermoplastic resin manufacturing method of the present invention, an antidripping agent, an impact enhancer, a plasticizer, an inorganic additive, a heat stabilizer, an antioxidant, a compatibilizer, a light stabilizer, a pigment, and / or a dye may be added according to each use. The inorganic additives to be added include asbestos, glass fibers, talc, ceramics, and sulfates, which may be used in an amount of 0 to 30 parts by weight based on 100 parts by weight of the base resin of the present invention.

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) rubber modified styrene resin, (B) polyphenylene ether resin, (C) cyclic alkylphosphonic acid and (D) aromatic phosphate ester used in Examples and Comparative Examples illustrated in Table 1 below The manufacture and specifications are as follows.

(A) Rubber modified styrene resin

(a ₁ ) Styrene-containing graft copolymer resin

(a ₁₁ ) Styrene-containing graft copolymer resin having an acrylonitrile content of 5% by weight

Add 50 parts by weight of butadiene rubber latex solids, 47.5 parts by weight of styrene, 2.5 parts by weight of acrylonitrile and 150 parts of deionized water, and add 1.0 parts of potassium oleate, 0.4 parts of cumene hydroperoxide, 0.2 parts of mercaptan-based chain transfer agent, and glucose to the total solids. 0.4 parts of iron sulfate, 0.01 parts of iron sulfate and 0.3 parts of pyrophosphate sodium salt were added thereto, and the reaction was completed at 75 ° C. for 5 hours to prepare a graft latex. 0.4 parts by weight of sulfuric acid was added to the solid content of the resin and solidified to prepare a graft copolymer resin powder.

(a ₁₂ ) Styrene-containing graft copolymer resin having an acrylonitrile content of 15% by weight

Except for adding 50 parts by weight of butadiene rubber latex solids, 42.5 parts by weight of styrene and 7.5 parts by weight of acrylonitrile was prepared in the same manner as described above.

(a ₁₃ ) Styrene-containing graft copolymer resin having an acrylonitrile content of 24% by weight

Butadiene rubber latex was prepared in the same manner as above except that 50 parts by weight of solid, 38 parts by weight of styrene and 12 parts by weight of acrylonitrile were added.

(a ₂ ) Styrene-based resin

(a ₂₁ ) General Purpose Polystyrene (GPPS)

GPPS (manufactured by Cheil Industries, Ltd., trade name HF-2680) having an average molecular weight of 210,000 was used.

(a ₂₂ ) Rubber reinforced styrene resin (HIPS)

Rubber reinforced styrene resin (brand name HG-1760S) manufactured by Cheil Industries, Ltd. was used. The butadiene rubber used had a particle size of 0.4 μm and a rubber content of 7 wt%.

(B) polyphenylene ether (PPE) resin

Poly (2,6-dimethyl-phenylether) (trade name P-402) of Asahi Kasei Co., Ltd., Japan, was used, and the particle size was in the form of a powder having an average particle diameter of several tens of micrometers.

(C) cyclic alkyl phosphonic acid compounds

Antiblaze 1045 (8% methyl-bis (5-ethyl-2-methyl-1,3,2, -dioxaphosphorinan-5yl) methyl methyl phosphonic acid ester P oxide with a phosphorus content of 20.8% and 85% methyl-bis (5-ethyl-2-methyl-1,3,2, -dioxaphosphorinan-5yl) phosphonic acid ester P, P'-dioxide) was used.

(D) Aromatic Phosphate Ester Compounds

Triphenyl phosphate having a melting point of 48 ° C. was used.

Each of the components in the composition shown in Table 1 was extruded at a temperature range of 200 ~ 280 ℃ in a conventional twin screw extruder to produce a pellet. The prepared pellets were dried at 80 ° C. for 3 hours and then injected into a 6 Oz injection machine under conditions of a molding temperature of 180 to 280 ° C. and a mold temperature of 40 to 80 ° C. to prepare a specimen.

The prepared specimens were measured for flame retardancy at 1/12 "thickness in accordance with UL 94 VB flame retardancy regulations, and Izod impact strength was measured under ASTM 256A at 1/8" thickness. Heat resistance was measured at a 5 kgf load in accordance with ASTM D 1525. The measurement results are shown in Table 1.

Item Example Comparative Example One 2 3 One 2 3 4 5 (A) Rubber modified styrene resin (a ₁ ) (a ₁₁ ) 20 20 20 20 30 - - - (a ₁₂ ) - - - - - 20 - - (a ₁₃ ) - - - - - - 20 - (a ₂ ) (a ₂₁ ) 25 50 - 25 35 25 25 - (a ₂₂ ) 25 - 50 25 35 25 25 70 (B) PPE resin 30 30 30 30 - 30 30 30 (C) cyclic alkylphosphonic acids 10 7 3 - - - - - (D) Aromatic Phosphate Ester - 4 8 15 15 15 15 15 UL 94, 1/12 " V-0 V-0 V-0 V-1 Fail V-1 V-1 V-1 Izod impact strength (1/8 ") 38 32 35 32 40 25 23 11 Vicat softening Temp. (℃) 92 90 88 84 70 85 85 84

As shown in Table 1, Examples 1-3 using the graft copolymer resin (a ₁₁ ) having an acrylonitrile content of 5% by weight, except for the rubber component, did not contain acrylonitrile at all. It showed superior impact strength compared to Example 5, and also showed excellent impact strength compared to Comparative Examples 3 and 4 containing 15% by weight or more of acrylonitrile. In the case of Comparative Example 1-5 using aromatic phosphate ester alone as a flame retardant, it was confirmed that heat resistance was reduced.

The present invention has the effect of providing a thermoplastic resin composition having excellent flame retardancy and impact strength by using a cyclic alkyl phosphonic acid compound as a flame retardant in a rubber-modified styrene resin and a polyphenylene ether resin blend having a specific acrylonitrile content. .

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 (4)

(A) (a ₁ ) Styrene-containing graft air prepared by graft polymerization of 10 to 60 parts by weight of a rubber component and 90 to 40 parts by weight of a styrene-acrylonitrile copolymer resin having an acrylonitrile content of 0.5 to 10% by weight. copolymer resin 10 to 60 parts by weight of (a ₂₎ 90-40 parts by weight of a styrene-based resin containing a rubber component, 0 to 20% by weight; (B) 5 to 60 parts by weight of polyphenylene ether resin; And (C) 2 to 30 parts by weight of the cyclic alkyl phosphonic acid compound based on 100 parts by weight of the base resin comprising (A) + (B); Flame-retardant thermoplastic resin composition, characterized in that consisting of. The flame retardant thermoplastic resin composition of claim 1, wherein the resin composition further comprises 0 to 20 parts by weight of aromatic phosphate ester. The flame-retardant thermoplastic resin composition of claim 1, wherein the cyclic alkyl phosphonic acid compound (C) is represented by the following Chemical Formula 1. [Formula 1] Wherein R ₁ and R ₂ are each independently an alkyl group of C _1-4 and x is 0 or 1. The flame retardant thermoplastic resin composition of claim 1, wherein the resin composition further comprises an antidropping agent, an impact enhancer, a plasticizer, an inorganic additive, a heat stabilizer, an antioxidant, a compatibilizer, a light stabilizer, a pigment, and / or a dye. .