KR20060079518A - Styrene thermoplastic resin composition with high impact strength and chemical resistance - Google Patents

Abstract

The thermoplastic resin composition according to the present invention comprises (A) 20 to 45 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 0.4 µm; And (B) 40 to 80 weight percent SAN resin having an acrylonitrile content of 30 to 36 weight percent and (b2) 20 to 60 weight percent SAN resin having an acrylonitrile content of 37 to 43 weight percent. It consists of 55-80 weight part of copolymer resins, It is characterized by the above-mentioned.

Acrylonitrile, Styrene, Impact Resistance, Chemical Resistance, Fluidity

Description

Styrene Thermoplastic Resin Composition with High Impact Strength and Chemical Resistance

Field of invention

The present invention relates to a styrene-based thermoplastic resin composition excellent in impact resistance and chemical resistance. More specifically, the present invention is to improve the chemical resistance to acetic acid while maintaining a certain level of impact strength and fluidity by controlling the acrylonitrile content and molecular weight of the styrene-acrylonitrile resin (hereinafter referred to as "SAN") matrix It relates to a styrene-based thermoplastic resin composition.

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 vinyl 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. The ABS resin thus prepared is widely used in parts, interior and exterior materials, automotive parts and general merchandise of electric and electronic products due to its excellent impact resistance, chemical resistance, heat resistance and mechanical strength and easy molding process.

However, in case of interior and exterior materials of electric and electronic products which are repeatedly stressed by driving of motor such as blender, washing machine, fan, etc., they must endure without breaking or breaking for a certain period of time, so they have excellent impact resistance and strong chemicals such as acetic acid. In addition, ABS resins with a certain degree of crack-resistant properties are required.

Conventionally, in order to improve the impact resistance of the ABS resin, a method of increasing the molecular weight of the styrene-acrylonitrile resin (hereinafter referred to as “SAN resin”) in the ABS resin and increasing the rubber content was used. However, such a conventional method has a disadvantage in that impact resistance is improved but fluidity is lowered.

Therefore, in order to solve the problems described above, the present inventors have described two types of SANs having different acrylonitrile contents and weight average molecular weights as a matrix resin in g-ABS resin made of a rubbery polymer having an average particle size of 0.25 to 0.4 µm. The use of a mixture of resins led to the development of a styrene-based thermoplastic resin composition having excellent impact resistance and chemical resistance to acetic acid.

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

Another object of the present invention is to provide a styrene-based thermoplastic resin composition excellent in chemical resistance to acetic acid.

Still another object of the present invention is to provide a styrene-based thermoplastic resin composition that maintains desirable fluidity.

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

Summary of the Invention

The thermoplastic resin composition having excellent impact resistance and chemical resistance may include (A) 20 to 45 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 0.4 µm; And (B) 40-80% by weight of a SAN resin having an acrylonitrile content of 30-36% by weight and (b) 20-60% by weight of a SAN resin having an acrylonitrile content of 37-43% by weight. It is characterized by consisting of; 55 to 80 parts by weight of copolymer resin.

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

Detailed Description of the Invention

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

The g-ABS resin (A) used in the present invention is prepared by graft polymerization of styrene-based monomers and monomers such as acrylonitrile in the presence of a rubbery polymer having an average particle size of 0.25 to 0.4 µm. It can be prepared by suspension polymerization, emulsion polymerization method, etc. It is preferable to be prepared by emulsion graft polymerization method because of the advantages such as good physical property balance and excellent gloss, and the product can be diversified and create high added value. .

As for the average particle diameter of the rubbery polymer used for this invention, the medium particle diameter of 0.25-0.40 micrometer is preferable, and about 0.28-0.38 micrometer is more preferable.

When the size of the rubbery polymer average particle size is less than 0.25 ㎛ can not obtain a shock resistance of more than a certain level required by the present invention, when applied in excess of 0.4 ㎛ causes a disadvantage that causes a significant drop in fluidity As for the average particle diameter of the rubbery polymer used for this invention, about 0.25-0.4 micrometers is preferable.

It is preferable that the graft ratio of said g-ABS resin (A) shall be 40 to 90%. When the graft ratio is lower than 40%, it is difficult to obtain a white powder having a uniform particle size distribution during solidification and drying, and also fisheye and pin holes as unplasticized particles on the surface of a molded product during extrusion or injection. Alternatively, a phenomenon such as sand surface may appear, leading to a decrease in surface glossiness. 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 at 20 to 45 parts by weight based on 100 parts by weight of the base resin. If the g-ABS resin content is less than 20 parts by weight, it is difficult to exhibit a predetermined level or more of the impact resistance required by the present invention. If the content of the g-ABS resin is more than 45 parts by weight, the fluidity is reduced to complete the present invention.

(B) SAN copolymer resin

SAN copolymer resin (B) of the present invention is (b1) 40 to 80% by weight of the SAN resin having an acrylonitrile content of 30 to 36% and (b2) 20 to 60 SAN resin having an acrylonitrile content of 37 to 43% Weight percent.

The SAN copolymer resin (B) of the present invention uses a SAN resin having an acrylonitrile content of 30 to 43 wt% and a weight average molecular weight of 100,000 to 160,000. When the acrylonitrile content is used at less than 30% by weight, the impact resistance, oil resistance and chemical chemical resistance cannot be improved. When the acrylonitrile content is used at an excess of 43% by weight, the impact resistance is improved, but the moldability is remarkably deteriorated. As such, the acrylonitrile content is preferably 30 to 43% by weight. In addition, when the weight average molecular weight of the SAN resin is less than 100,000, the resin tends to be easily broken. When the weight average molecular weight of the SAN resin is more than 160,000, the molecular weight is high, so that it is difficult to manufacture a linear structure, so the weight average molecular weight of the SAN resin is preferably 100,000 to 160,000.

When the weight average molecular weight and acrylonitrile content of the SAN copolymer resin (B) and the mixing ratio of the SAN resin (b1) and (b2) are outside the above ranges, the impact resistance and the chemical resistance against acetic acid to be achieved in the present invention. It is difficult to expect the improvement of and it is impossible to achieve the present invention by lowering the fluidity.

In the present invention, the SAN copolymer resin (B) is used at 55 to 80 parts by weight based on 100 parts by weight of the base resin.

If the content of the SAN copolymer resin is less than 55 parts by weight, there is a disadvantage that the compatibility with the ABS resin is lowered, and if it exceeds 80 parts by weight, the impact resistance is significantly reduced.

In addition, in the thermoplastic resin composition of the present invention, in mixing the g-ABS resin (A) and the SAN copolymer resin (B), the hindered phenol-based antioxidant, phosphite-based antioxidant, A metal stearate lubricant, a steramid lubricant, a silicone impact modifier, a HALS light stabilizer, an inorganic additive, a pigment and / or a dye, and the like may be further added, and may be manufactured by injection molding through a melt kneading process. Can be.

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-based lubricant is 0.1 to 3 parts by weight, steramid 0.5 to 7 parts by weight of the lubricant is added, 0.01 to 1 parts by weight of the silicone-based impact modifier, and 0.1 to 2 parts by weight of the Hals-based light stabilizer.

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) steramid lubricant, (D) antioxidant and (E) metal stearate lubricant used in the following Examples and Comparative Examples The specification 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

(b1) SAN resin

SAN resin having an acrylonitrile content of 32% by weight and a weight average molecular weight of 130,000 was used.

(b2) SAN resin

SAN resin having an acrylonitrile content of 41% by weight and a weight average molecular weight of 120,000 was used.

(C) steramid lubricant

N, N'-ethylene bis steramide was used as a steramid lubricant.

(D) antioxidant

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

(E) Metal Stearate Type Lubricant

Magnesium stearate was used as the metal stearate lubricant.

Examples 1-2

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 the prepared pellets to prepare a specimen for physical properties and chemical resistance evaluation.

Comparative Example 1

A specimen was prepared in the same manner as in Example 1 except that SAN resin (b1) having an acrylonitrile content of 32% by weight and a weight average molecular weight of 130,000 was used alone.

Comparative Example 2

A specimen was prepared in the same manner as in Example 1 except that SAN resin (b2) having an acrylonitrile content of 41 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 the SAN resin (b3) having an acrylonitrile content of 32% by weight and a weight average molecular weight of 180,000 was used alone.

Comparative Example 4

A specimen was prepared in the same manner as in Example 1 except that the SAN resin (b4) having an acrylonitrile content of 32% by weight and a weight average molecular weight of 80,000 was used alone.

Comparative Example 5

A specimen was prepared in the same manner as in Example 1, except that SAN resin (b5) having an acrylonitrile content of 41 wt% and a weight average molecular weight of 90,000 was used alone.

division Example Comparative Example One 2 One 2 3 4 5 (A) 25 25 25 25 25 25 25 B) (b1) 50 35 75 - - - - (b2) 25 40 - 75 - - - (b3) - - - - 75 - - (b4) - - - - - 75 - (b5) - - - - - - 75 (C) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (D) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (E) 0.2 0.2 0.2 0.2 0.2 0.2 0.2

* Each component in Table 1 is parts by weight.

The physical properties and the chemical resistance to acetic acid were measured for each of the physical property specimens and the chemical resistance evaluation specimens prepared according to the Examples and Comparative Examples.

(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 (5 kg, 200 ° C.).

(3) Chemical resistance: Fix the chemical resistance test specimen of 50 mm × 200 mm × 2.0 mm in 1/2 elliptical jig with a ratio of transverse radius: longitudinal radius of 4: 3 and acetic acid with water: glacial acetic acid ratio of 3: 7 The solution was applied on the specimen about 5 ml and after 10 minutes the specimen was removed from the jig and washed with water to observe the change of the surface.

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

division Example Comparative Example One 2 One 2 3 4 5 Notched Izod Impact Strength (1/4 ") (kgfcm / cm) 26 25 21 19 23 16 17 Notched Izod Impact Strength (1/8 ") (kgfcm / cm) 38 37 32 30 33 28 28 Flow index (g / 10min) 2.4 2.7 2.0 2.2 1.6 3.0 2.8 Chemical resistance (surface state) Good Good Fine crack Fine crack Fine crack crack Fine crack

From the results of Table 2, Examples 1 to 2 using a mixture of two SAN resins having different g-ABS resins and acrylonitrile contents and molecular weights compared with those of Comparative Examples 1 to 5 using only one SAN resin. It can be seen that the strength, fluidity, and chemical resistance are excellent.

The present invention is g-ABS resin made of a rubbery polymer having an average particle size of 0.25 ~ 0.4 ㎛; And by appropriately adjusting the content of two kinds of SAN resins having different acrylonitrile content and weight average molecular weight, the impact resistance of the thermoplastic resin composition can be maintained at the same time while improving the impact resistance and chemical resistance against acetic acid. Has

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) 20 to 45 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 0.4 m; And (B) A SAN copolymer resin consisting of 40 to 80 wt% of a SAN resin having an acrylonitrile content of 30 to 36% and (b2) 20 to 60 wt% of a SAN resin having an acrylonitrile content of 37 to 43% 55 to 80 parts by weight; A thermoplastic resin composition, characterized in that consisting of. The thermoplastic resin composition according to claim 1, wherein the SAN copolymer resin has a weight average molecular weight of 110,000 to 160,000 and a weight average molecular weight of 100,000 to 150,000 of (b2). The thermoplastic resin composition of claim 1, wherein the g-ABS resin (A) has a graft rate of 40 to 90%. The method of claim 1, wherein the resin composition further comprises a hindered phenolic antioxidant, phosphite antioxidant, steramid lubricant, metal stearate lubricant, silicone impact modifier, Hals light stabilizer The thermoplastic resin composition characterized by the above-mentioned.