KR100364234B1 - Preparation method of thermoplastic resin with excellent impact strength - Google Patents

Abstract

PURPOSE: A method for preparing a thermoplastic resin is provided, to improve impact strength and color stability compared with those of a polybutadiene rubber graft ABS resin, without deterioration of the physical properties of the resin. CONSTITUTION: The method comprises the steps of polymerizing 10-50 wt% of a styrene monomer and 50-90 wt% of a butadiene monomer to prepare a styrene-butadiene rubber latex, and two-step graft copolymerizing 20-50 wt% of a styrene monomer and 20-40 wt% of an acrylonitrile monomer onto 10-70 wt% of the obtained latex by using 0.1-0.5 wt% of an oxidation-reduction initiator to prepare a graft ABS (acrylonitrile-butadiene-styrene) resin; two-step graft emulsion copolymerizing 30-50 wt% of a styrene monomer and 20-30 wt% of an acrylonitrile monomer onto 40-60 wt% of polybutadiene to prepare an ABS resin; and mixing 5-15 wt% of the first ABS resin with the second ABS resin and solidifying the mixture.

Description

Manufacturing method of thermoplastic resin excellent in impact strength

The present invention relates to a method for preparing a thermoplastic resin composition which improves the impact strength and appearance of a graft copolymer prepared by emulsion polymerization, and more specifically, acrylonitrile-butadiene-styrene (hereinafter referred to as graft ABS). In preparing graft polymer latex, a styrene-butadiene rubber latex is prepared, and graft copolymerization of styrene and acrylonitrile is performed to prepare graft ABS, followed by mixing with graft ABS using butadiene rubber. The present invention relates to a method for producing a thermoplastic resin having improved mechanical properties and productivity such as glossiness, color stability and impact resistance.

In general, ABS resin is widely used in electronics, home appliances, and office equipment because of excellent physical properties such as processability, impact resistance, chemical resistance, etc., and the use of automobile interior and exterior materials is also increasing.

Emulsion polymerization, suspension polymerization and bulk polymerization can be used for the polymerization of ABS resin, but the ABS resin by emulsion polymerization method has excellent self-property due to the disadvantage that the mechanical and chemical properties are reduced due to the residual of various reaction additives in the resin. Bulk polymerization or suspension polymerization may also be used.

In order to increase the impact resistance and heat resistance of the ABS resin, one or two of the existing styrene monomers, substituted vinyl cyanide compounds, and rubber elastomers may be grafted or copolymerized, or the ABS resin may be polycarbonate, The method of blending with resin, such as polyethylene terephthalate, polyamide, and polyphenylene oxide, is also used. However, this method of improving the heat resistance and impact resistance can sometimes obtain better physical properties than the existing ABS, but it requires a price increase and additional equipment because it needs to be polymerized using a new monomer or uses a new resin. In blending with resin, especially kneading problem becomes a problem.

It is an object of the present invention to provide a method for producing a thermoplastic resin having excellent impact resistance and color stability without economical cost while improving mechanical and chemical properties of ABS resin.

The present invention is to prepare a styrene butadiene rubber latex by polymerizing (A) 10 to 50% by weight of styrene monomer, 90 to 50% by weight of butadiene monomer, 20 to 50% by weight of styrene monomer in 10 to 70% by weight of the latex Graft ABS obtained by graft copolymerization of 20 to 40% by weight of the nitrile monomer; and (B) 30 to 50% by weight of styrene monomer, 20 to 30% by weight of acrylonitrile monomer and 40 to 60% by weight of polybutadiene. It relates to a method for producing a thermoplastic resin excellent in impact resistance and color stability, characterized in that the blended ABS in two steps graft emulsion polymerization at a constant ratio.

Styrene-butadiene rubber latex obtained by polymerizing 10 to 50% by weight of the styrene monomer of the present invention and 90 to 50% by weight of the butadiene monomer is ferric sulfate, an ethylenediamine tetraacetic acid-4 sodium salt, sodium formaldehyde as a redox initiator catalyst. It is prepared by adding sulfoxylate and 0.1 to 0.5% by weight of initiator and 0.5 to 3.0% by weight of emulsifier, and then 20 to 50% by weight of styrene monomer in 10 to 70% by weight, preferably 40 to 60% by weight of this rubber latex. 20 to 40% by weight of acrylonitrile monomers are firstly prepared by performing a two-step emulsion polymerization using ferric sulfate, 4-sodium pyrophosphate, dextrose, and an initiator as an oxidation-reduction initiator catalyst to prepare graft ABS latex. . At this time, a two-step polymerization method is used to control the form of styrene and acrylonitrile grafted to the rubber particles. Styrene monomers usable in the present invention include aromatic vinyl monomers such as styrene, alphamethylstyrene, alphachlorostyrene, vinyltoluene, divinylbenzene, pt-butylstyrene, 2,4-dimethylstyrene, acrylonitrile and methacryl Unsaturated monomers, such as a nitrile, etc. are mentioned. Secondly, 20 to 30% by weight of a styrene monomer and an acrylonitrile monomer are added to 10 to 70% by weight of polybutadiene latex, preferably 40 to 60% by weight, which is a tertiary dodecylmercaptan and an oxidation-reduction initiator catalyst. Reaction by adding 4-sodium pyrophosphate, dextrose, ferrous sulfate and 0.1 to 0.5% by weight of initiator and 0.5 to 3.0% by weight of emulsifier, and continuously adding the remaining 20 to 30% by weight of monomer together for one hour At this time, the molecular weight modifier and cumene hydroperoxide are continuously added together to prepare grafted ABS using a two-step polymerization method. Polymerization initiators usable in the present invention include water-soluble initiators such as potassium persulfate and ammonium persulfate or cumene hydroperoxide, t-butylhydroperoxide, isocumylhydroperoxide, p-pentanehydroperoxide and t-butylperoxide. Although fat soluble initiators such as benzoate, t-butylperacetate, and dibenzoyl peroxide can be used alone or in combination, they are ideally used as mixed fat soluble initiators. After mixing the first-produced ABS latex and the second-produced ABS latex at a certain ratio, the first-produced ABS latex is mixed to 5 to 15% by weight, and then acids such as sulfuric acid, hydrochloric acid, and nitric acid, calcium chloride, and magnesium sulfate. The latex is coagulated using the same metal salt to prepare graft ABS after washing and drying. If necessary, a certain amount of SAN and lubricant are added to the powder of the graft ABS to injection-form the physical specimen.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

100 wt% pure water, 2 wt% potassium rosinate emulsifier, 45 wt% styrene butadiene rubber latex, 20 wt% styrene monomer, 8 wt% acrylonitrile, 0.15 wt% dextrose, 0.15 tertiary dodecyl mercaptan Into a weight%, cumene hydroperoxide 0.1% by weight, a mixture of 0.01% by weight of ferrous sulfate and 0.2% by weight of 4-sodium pyrophosphate was added to perform a one-step reaction by polymerization heat, styrene monomer 19 at 65 ℃ Weight%, 8% by weight of acrylonitrile, 0.3% by weight of tertiary dodecyl mercaptan, and 0.28% by weight of cumene hydroperoxide are continuously added over one hour. After polymerization, the dispersion of antioxidant is added at 60 ° C. and cooled to room temperature. The latex thus prepared was mixed with 95% by weight of the latex prepared in Comparative Example 1, coagulated, washed, and dried to prepare a specimen by mixing SAN and a lubricant, and the physical properties thereof were shown in Table 1 below.

Example 2

Except that the mixing ratio of the latex in Example 1 is 10:90 was prepared in the same manner as in Example 1 and shown in Table 1 to evaluate the physical properties.

Example 3

Except that the mixing ratio of the latex in Example 1 is 15:85 was prepared in the same manner as in Example 1 and shown in Table 1 to evaluate the physical properties.

Comparative Example 1

100% pure water, 2% by weight potassium rosin, emulsifier, 45% by weight polybutadiene latex (50% solids content), 20% by weight styrene monomer, 8% by weight acrylonitrile, 0.15% by weight dextrose At 60 ° C., 20% by weight of pure water and 0.35% by weight of 4-sodium pyrophosphate and 0.1% by weight of ferrous sulfate were added thereto, followed by primary polymerization by heat of polymerization, 19% by weight of styrene and acrylonitrile at 65 ° C. 8% by weight, 0.3% by weight of tertiary dodecyl mercaptan and 0.28% by weight of cumene hydroperoxide are continuously added over one hour to carry out a two-step reaction. After polymerization, the dispersion of antioxidant was added, cooled to room temperature, solidified with sulfuric acid, washed and dried, and the physical properties of the specimens injected by mixing SAN and lubricants are shown in Table 1.

Comparative Example 2

100% pure water, 2% by weight potassium rosin, emulsifier, 45% by weight polybutadiene latex (50% solids content), 20% by weight styrene monomer, 8% by weight acrylonitrile, 0.15% by weight dextrose At 60 ° C., 20% by weight of pure water and 0.35% by weight of 4-sodium pyrophosphate and 0.01% by weight of ferrous sulfate were added thereto, followed by reaction for one hour, 19% by weight of styrene and 8% by weight of acrylonitrile at a constant temperature of 70 ° C. 0.3 wt% of tertiary dodecyl mercaptan and 0.28 wt% of cumene hydroperoxide were continuously added over three hours to terminate the reaction. After polymerization, the dispersion of antioxidant was added, cooled to room temperature, and then, 5 wt% of the latex was mixed with 95 wt% of the latex made in Comparative Example 1, coagulated with sulfuric acid, washed, and dried to prepare a specimen by mixing SAN and a lubricant. After evaluation of physical properties are shown in Table 1.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Izod impact strength 39.0 41.0 41.5 34.0 38.6 Flow index 1.13 1.16 1.17 1.18 1.24 Rockwell hardness 90.6 92.9 93.0 92.3 91.5 Vicat Softening Branch 91.8 91.9 92.7 92.2 92.9 Color difference (ΔΕ) 19.3 19.6 19.8 18.9 19.8 Yellow Degree (YI) 26.9 27.1 27.2 25.9 26.8 Whiteness (WI) 69.5 69.5 69.3 70.1 69.2

Property evaluation method

1) Izod impact strength was measured by ASTM D256 (1/4 ", 23 ℃).

2) Flow index (MI): measured according to ASTM D1238 (200 ° C., 5 kg).

3) Rockwell hardness (R scale): measured according to ASTM D785.

4) Vicat softening point (℃): measured according to ASTM D306.

5) Color difference (ΔΕ), yellowness (YI), whiteness (WI): measured according to ASTM D1925.

As described above, a styrene-butadiene rubber latex is prepared, and graft ABS resin using a graft ABS resin obtained by graft copolymerization of styrene and acrylonitrile and a polybutadiene rubber is used in comparison with the polybutadiene rubber graft ABS resin. Impact strength and color stability are excellent.

Claims (2)

(A) 10 to 50% by weight of styrene monomer, 90 to 50% by weight of butadiene monomer to polymerize to produce styrene butadiene rubber latex, 10 to 70% by weight of the latex 20 to 50% by weight of acrylonitrile monomer 20 Graft ABS with 2 to 40% by weight, two-step graft copolymerization using 0.1 to 0.5% by weight of an oxidation-reduction initiator; (B) using a 30 to 50% by weight of styrene monomer, 20 to 30% by weight of acrylonitrile monomer, 40 to 60% by weight of polybutadiene to prepare a two-stage graft emulsion-polymerized ABS (A) and (B) Mixing but (A) is a method for producing a thermoplastic resin excellent in impact strength, characterized in that after mixing so as to mix 5 to 15% by weight. The method of claim 1, wherein the redox initiator is added at least one member selected from the group consisting of 4-sodium ethylenediamine, tetraacetate, sodium formaldehyde sulfoxylate, 4-sodium pyrophosphate, dextrose. Method for producing a thermoplastic resin excellent in impact strength, characterized in that.