KR100439629B1 - Thermoplastic Resin Composition Having High Impact Strength, High Fatigue Strength and High Flowability - Google Patents

Abstract

The thermoplastic resin composition having excellent impact resistance, fatigue strength and fluidity of the present invention is (A) 15 to 40 weight of g-ABS resin prepared by emulsion graft polymerization using a rubbery polymer having an average particle size of 0.25 to 0.40 µm. part; (B) (b ₁₎ and a nitrile content of 20-30% of an acrylic and having a weight average molecular weight of 350000-400000, the molecular weight distribution is from 3.0 to 3.5 is branched (branched) SAN resin 15~50% by weight and (b ₂₎ 60 to 85 parts by weight of a SAN copolymer resin composed of 85 to 50% by weight of a SAN resin having an acrylonitrile content of 20 to 35% and a weight average molecular weight of 100,000 to 140,000; And (C) 1 to 7 parts by weight of (C) ethylenebisstearoamide, based on 100 parts by weight of the total (A) + (B), and optionally, a specific hindered phenolic antioxidant, phosphite antioxidant, and metal stearate. It may further include a rate-based lubricant, a silicone-based impact modifier, a Hals-based light stabilizer and an amine antistatic agent.

Description

Thermoplastic Resin Composition Having High Impact Strength, High Fatigue Strength and High Flowability}

Field of invention

The present invention relates to a thermoplastic resin composition having excellent impact resistance, fatigue strength and flowability. More specifically, the present invention is acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as 'g-ABS resin'), acrylonitrile content, weight average molecular weight and number average molecular weight of two different styrene-acryl The present invention relates to a thermoplastic resin composition having excellent impact resistance, fatigue strength and fluidity, comprising a ronitrile copolymer (hereinafter, referred to as SAN resin) and ethylene bis stearamide.

Background of the Invention

Acrylonitrile-butadiene-styrene copolymer resin (hereinafter referred to as 'ABS resin') is prepared by graft polymerization of an styrene monomer, an aromatic vinyl compound, and an acrylonitrile monomer, an unsaturated nitrile compound, in the presence of a butadiene rubbery polymer. do. At this time, the desired resin can be obtained by adjusting the physical properties of the rubbery polymer, g-ABS resin, and matrix polymer used. ABS resin thus prepared is widely used in electric and electronic parts, interior and exterior materials, automotive parts and general merchandise because of excellent impact resistance, chemical resistance, chemical resistance, heat resistance, mechanical strength and easy molding process.

However, in the case of the interior and exterior materials of electrical and electronic products that are repeatedly stressed by the driving of a motor such as a mixer, a washing machine, a fan, and the like, the ABS has excellent impact resistance and fatigue strength because it must endure without breaking or breaking for a certain period of time. Resin is required and also with good fluidity to facilitate the manufacture of molded articles of complex structure.

Conventionally, in order to improve the impact resistance of the ABS resin, a method of increasing the molecular weight of the SAN resin in the ABS resin and increasing the rubber content was used. However, in such a conventional method, impact resistance is improved, but fluidity is lowered, and it is difficult to obtain a desired level of fatigue strength unless the molecular weight and molecular weight distribution of the SAN resin are controlled.

Therefore, in order to solve the above problems, the inventors have found that acrylonitrile content, weight average molecular weight, and number average molecular weight of g-ABS resin made of a rubbery polymer having an average particle size of 0.25 to 0.40 μm as a matrix resin. By mixing two different SAN resins and using ethylene bis stearamide as an additive for improving the flowability, it is possible to develop a thermoplastic resin composition having excellent impact resistance, fatigue strength and excellent flowability.

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

Still another object of the present invention is to provide a thermoplastic resin composition having excellent fatigue strength.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent flowability.

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

The thermoplastic resin composition excellent in impact resistance, fatigue strength and fluidity of the present invention is (A) 15 to 40 weight of g-ABS resin prepared by emulsion graft polymerization using a rubbery polymer having an average particle size of 0.25 to 0.40 µm. part; (B) (b ₁₎ an acrylic nitrile content is 20 ~ 30% by, the branched (branched) SAN resin 15~50% by weight and the average molecular weight of 350000-400000, the molecular weight distribution is from 3.0 to 3.5 and (b ₂ 60 to 85 parts by weight of a SAN copolymer resin consisting of 85 to 50% by weight of a SAN resin having an acrylonitrile content of 20 to 35% and a weight average molecular weight of 100,000 to 140,000; And (A) and (B) 1 to 7 parts by weight of (C) ethylenebisstearoamide, based on 100 parts by weight of the total, wherein (B) SAN copolymer resin has a total molecular weight distribution of 2.5 to 3.5. do. Hereinafter, the configuration of the present invention in detail.

(A) graft ABS resin (g-ABS resin)

The g-ABS resin (A) of the present invention is prepared by the emulsion graft polymerization method using a medium particle rubbery polymer having an average particle size of 0.25 to 0.40 mu m.

In the average particle size of the rubbery polymer, the average particle size of the rubbery polymer usable in the present invention is preferably in the range of 0.25 to 0.40 m, more preferably in the range of 0.28 to 0.38 m.

It is preferable that the graft ratio of said g-ABS resin (A) shall be 40 to 90%. If the graft rate is lower than this, it is difficult to obtain a white powder having a uniform particle size distribution during solidification and drying, as well as fisheye, pinhole or sandsurface as unplasticized particles on the surface of the molded part during extrusion or injection. ), The surface gloss is reduced. In addition, when the graft ratio exceeds 90%, physical property degradation such as impact strength, fluidity, and surface gloss occurs.

In the present invention, the g-ABS resin (A) is preferably used in an amount of 15 to 40 parts by weight based on 100 parts by weight of the base resin. When the g-ABS resin content is 15 parts by weight or less, it is difficult to exhibit a shock resistance or higher than a certain level required by the present invention, and when it is 40 parts by weight or more, fluidity is lowered to complete the present invention.

(B) SAN copolymer resin

SAN copolymer resin (B) of the present invention (b ₁ ) branched SAN resin 15-50 having an acrylonitrile content of 20 to 30%, a weight average molecular weight of 350,000 to 400,000, and a molecular weight distribution of 3.0 to 3.5 Weight% and (b ₂ ) 85-50% by weight of a SAN resin having an acrylonitrile content of 20 to 35% and a weight average molecular weight of 100,000 to 140,000.

It is preferable that the total molecular weight distribution of the said SAN copolymer resin (B) is 2.5-3.5, and the weight average molecular weight is 150,000-250,000.

The mixing ratio of the branched SAN resin (b ₁ ) and SAN resin (b ₂ ) is 15 to 50% by weight of the branched SAN resin (b ₁ ), the SAN resin (b ₂ ) 85 to 50 wt% is preferred.

When the molecular weight distribution of the SAN copolymer resin (B) and the mixing ratio of the SAN resins (b ₁ ) and (b ₂ ) are out of the above ranges, the impact resistance, fatigue strength and flowability to be achieved in the present invention are expected to be improved. Difficult to do

In the present invention, the SAN copolymer resin (B) is used in an amount of 60 to 85 parts by weight based on 100 parts by weight of the base resin.

(C) Ethylenebisstearoamide

The thermoplastic resin composition of this invention is obtained by mix | blending ethylene bis stearamide (C) with the said base resin (A) + (B) as an additive.

In the thermoplastic resin composition of the present invention, the ethylene bis stearamide (C) is preferably added in an amount of 1 to 7 parts by weight based on 100 parts by weight of the base resin (A) + (B). When the amount of ethylene bis stearamide added is out of the above range, the fluidity and impact resistance effects are insufficient, and discoloration of the injection molding and gas silver may occur.

In addition, the thermoplastic resin composition of the present invention, in mixing the g-ABS resin (A), the SAN copolymer resin (B) and ethylene bis stearamide (C), selectively hindered phenol type specific for each application Antioxidants, phosphite antioxidants, metal stearate lubricants, silicone impact modifiers, HALS light stabilizers and amine antistatic agents, inorganic additives, pigments and / or dyes, and the like may be further added. It can be manufactured by injection molding through a process.

In this case, the hindered phenolic antioxidant is 0.05 to 2 parts by weight based on 100 parts by weight of the resin composition, the phosphite antioxidant is 0.05 to 2 parts by weight, the metal stearate lubricant is 0.1 to 3 parts by weight, silicone-based impact modifier Is 0.01 to 1 part by weight, a halogen-based light stabilizer is 0.1 to 2 parts by weight, amine-based antistatic agent is added in 0.1 to 2 parts by weight.

In the present invention, it is preferable to use octadil-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate as the hindered phenolic antioxidant, and the phosphite antioxidant It is preferable to use disteanil pentaerythritol diphosphite, and magnesium stearate is preferably used as the metal stearate lubricant. In addition, polydimethylsiloxane is preferable as the silicone-based impact modifier, bis (2,2,6,6, -tetramethyl-4-piperidinyl) sebacate as the Hals-based light stabilizer, and N as the amine antistatic agent. -Hydroxyethyl-N (2-hydroxy alkyl) amine is preferred.

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) g-ABS resin, (B) SAN copolymer resin, (C) ethylenebisstearoamide, (D) antioxidant, (E) metal lubricant, (F) used in the following Examples and Comparative Examples ) The specification of impact modifier is as follows.

(A) g-ABS resin

A g-ABS resin having a core-shell form was used by graft emulsion polymerization of a rubbery polymer having a rubber particle diameter of 0.32 μm.

(B) SAN copolymer resin

(b ₁ ) Branched SAN Resin

Branched SAN resins having an acrylonitrile content of 25% by weight, a weight average molecular weight of 380,000 and a molecular weight distribution of 3.2 were used.

(b ₂ ) SAN resin

SAN resins having an acrylonitrile content of 28.5 wt% and a weight average molecular weight of 120,000 were used.

(C) Ethylenebisstearoamide

HI-LUBE was used as N, N 'Ethylene bis Stearamide.

(D) antioxidant

Octadiyl-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate was used as a hindered phenolic antioxidant.

(E) metal lubricant

Magnesium stearate was used as the stearate-based metal lubricant.

(F) impact modifier

Dimethylpolysiloxane was used as the silicone-based impact modifier.

Examples 1-4

Each of the components was added in an amount as shown in Table 1, followed by melting and kneading extrusion to prepare pellets. At this time, the extrusion was used L / D = 29, 45 mm diameter twin screw extruder and the cylinder temperature was set to 220 ℃. Injection molding into the prepared pellets to prepare a physical specimen.

Comparative Example 1

Specimens were prepared in the same manner as in Example 1 except that a branched SAN resin (b ₁ ) having an acrylonitrile content of 25% by weight, a weight average molecular weight of 380,000, and a molecular weight distribution of 3.2 was used alone.

Comparative Example 2

A specimen was prepared in the same manner as in Example 1 except that SAN resin (b ₂ ) having an acrylonitrile content of 28.5 wt% and a weight average molecular weight of 120,000 was used alone.

Comparative Example 3

A specimen was prepared in the same manner as in Example 1 except that ethylene bis stearamide (C) was not used.

division Component (parts by weight) g-ABS resin (A) SAN resin (B) Ethylene Bisstearoamide (C) Antioxidant (D) Metal lubricant (E) Impact modifier (F) (b ₁ ) (b ₂ ) Example One 26 25 48 3.0 0.1 0.2 0.02 2 26 35 38 3.0 0.1 0.2 0.02 3 23 26 51 3.0 0.1 0.2 0.02 4 26 25 48 4.0 0.1 0.2 0.02 Comparative Example One 26 74 - 3.0 0.1 0.2 0.02 2 26 - 74 3.0 0.1 0.2 0.02 3 26 25 48 - 0.1 0.2 0.02

The physical properties of the specimens prepared by the above Examples and Comparative Examples were measured by the following methods.

(1) Notched Izod impact strength was measured according to ASTM D256 (1/4 ", 1/8", 23 ° C).

(2) The flow index was measured according to ASTM D1238 (10 kg, 220 ° C.).

(3) Fatigue strength was measured by applying INSTRON Model 8872 to tensile test specimens of ASTM D638 standard at maximum frequency of 1250N and minimum load of 350N at a frequency of 5Hz.

The physical property measurement results are shown in Table 2 below.

division Properties Notched Izod Impact Strength (1/4 ″) (kgfcm / cm) Notched Izod Impact Strength (1/8 ″) (kgfcm / cm) Flow index (g / 10 min) Breakage Life (Cycles) Example One 26 43 11 58,900 2 32 52 8 62,200 3 22 36 13 52,300 4 27 45 12 57,600 Comparative Example One 38 60 3 68,700 2 17 29 20 36,400 3 22 36 9 54,800

From the results of Table 2, in Comparative Example 1 using only a branched SAN resin (b ₁ ) having a weight average molecular weight of 380,000 as the SAN resin, the impact index and the fatigue strength were excellent, but the flow index was very low. In Comparative Example 2 using only SAN resin (b ₂ ) having a weight average molecular weight of 120,000 as the SAN resin, the flow index was excellent, but the impact strength and the fatigue strength were found to be very low.

In addition, in the case of Comparative Example 3 in which ethylene bis stearamide was not used, all of the impact strength, fatigue strength, and flow index were found to decrease.

The present invention uses g-ABS resin made of a rubbery polymer having an average particle size of 0.25 to 0.40 µm, two kinds of SAN resins and ethylene bis stearamides having different acrylonitrile content, weight average molecular weight and number average molecular weight. By adjusting the weight average molecular weight of the SAN copolymer resin to 150,000 to 250,000 and the molecular weight distribution to 2.5 to 3.5, it has the effect of providing not only impact resistance and fatigue resistance but also a thermoplastic resin composition with improved fluidity.

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) 15 to 40 parts by weight of a g-ABS resin prepared by emulsion graft polymerization using a rubbery polymer having an average particle size of 0.25 to 0.40 mu m; (B) (b ₁₎ and a nitrile content of 20-30% of an acrylic and having a weight average molecular weight of 350000-400000, the molecular weight distribution is from 3.0 to 3.5 is branched (branched) SAN resin 15~50% by weight and (b ₂₎ 60 to 85 parts by weight of a SAN copolymer resin composed of 85 to 50% by weight of a SAN resin having an acrylonitrile content of 20 to 35% and a weight average molecular weight of 100,000 to 140,000; And based on 100 parts by weight of the total (A) + (B) (C) 1 to 7 parts by weight of ethylenebisstearoamide; A thermoplastic resin composition, characterized in that consisting of. The thermoplastic resin composition according to claim 1, wherein the SAN copolymer resin (B) has a weight average molecular weight of 150,000 to 250,000, and a molecular weight distribution of 2.5 to 3.5. The method of claim 1, wherein the resin composition optionally further comprises a hindered phenolic antioxidant, phosphite antioxidant, metal stearate-based lubricant, silicone-based impact enhancer, Hals-based light stabilizer and amine-based antistatic agent Thermoplastic resin composition. According to claim 3, wherein the hindered phenolic antioxidant is 0.05 to 2 parts by weight based on 100 parts by weight of the resin composition, the phosphite antioxidant is 0.05 to 2 parts by weight, the metal stearate-based lubricant is 0.1 to 3 parts by weight , The silicone impact modifier is 0.01 to 1 part by weight, the Hals-based light stabilizer is 0.1 to 2 parts by weight, the amine antistatic agent is a thermoplastic resin composition, characterized in that 0.1 to 2 parts by weight.