KR100340312B1 - Thermoplastic Resin Composition for Excellent Impact Strength and High Flowability - Google Patents

Abstract

The thermoplastic resin composition having improved impact resistance and fluidity may comprise (A) 15 to 40 parts by weight of rubber-reinforced styrene-based graft copolymer resin containing rubber having an average particle diameter of 0.1 to 0.4 µm; (B) 25 to 45 parts by weight of a SAN resin (b ₁ ) having an acrylonitrile content of 25 to 35% by weight and a weight average molecular weight of 100,000 to 130,000, and an acrylonitrile content of 30 to 40% by weight and a weight average molecular weight of 35 to 65 parts by weight of the SAN resin (b ₂ ) having 80,000 to 120,000; And (C) 3 to 10 parts by weight of ethylene bis fatty acid amide based on 100 parts by weight of the base resin (A) + (B).

Description

Thermoplastic Resin Composition for Excellent Impact Strength and High Flowability}

Field of invention

The present invention relates to a thermoplastic resin composition having improved impact resistance and fluidity. More specifically, the present invention is a thermoplastic resin composition having improved impact resistance and fluidity by mixing and processing additives in rubber-reinforced styrene-containing graft copolymer and acrylonitrile-styrene copolymer (hereinafter referred to as SAN resin). It is about. More specifically, the present invention provides ethylene, which is an additive to rubber-reinforced styrene-containing graft copolymers containing rubber having an average particle diameter of 0.1 to 0.4 µm, and to two types of SAN resins having different acrylonitrile monomer compositions and weight average molecular weights. Provided is a thermoplastic resin composition in which the bis fatty acid amide is mixed and processed to maintain mechanical properties such as excellent impact strength, durability, and fluidity.

Background of the Invention

Rubber-reinforced styrenic resins have been widely used for various applications, such as being used as exterior materials for electrical appliances and office equipment because of their good processability, particularly excellent impact strength and good appearance.

Conventionally, rubber-reinforced styrene resin (hereinafter referred to as 'ABS resin') is an aromatic vinyl compound in the presence of a rubbery polymer such as butadiene-based styrene monomer and a typical acrylonitrile monomer among unsaturated nitrile-based compounds in emulsion polymerization method By graft polymerization. The method for preparing the resin is already known and the desired resin can be obtained by adjusting the physical properties of the rubbery polymer, the graft polymer and the matrix polymer to be used. The ABS resin thus prepared has a relatively good combination of physical properties such as impact resistance, mechanical strength, molding processability, and is widely used in electric and electronic parts and automobile parts.

However, in recent years, as the molded articles are lighter and thinner, the need for ABS resins having impact resistance and excellent flowability is increasing day by day. Therefore, in order to improve the impact resistance and fluidity of the ABS resin, a conventional method that meets these requirements has been introduced a method of lowering the molecular weight of the SAN resin in the ABS resin, lowering the rubber content, and adding various lubricants. However, it is difficult to satisfy fluidity, rigidity and impact resistance at the same time with such conventional methods.

In addition, graft copolymer resins are usually produced by block polymerization, block polymerization, suspension polymerization, emulsion polymerization, etc., and are produced by mixing alone or in accordance with properties. However, the bulk polymerization, which is most commonly used in graft copolymer resins, cannot produce a resin having various physical properties, in particular, a rubber having a high rubber content, despite advantages such as mass production and reduced manufacturing cost.

However, the graft copolymer resin prepared by the emulsion polymerization method uses a butadiene-based rubbery polymer having a rubber particle diameter of mostly 0.1 to 1.0 µm to add radical generating initiators such as pyrolysis initiators and redox initiators to acrylonitrile and styrene monomers. Graft polymerization, coagulation, dehydration and drying process to obtain fine powder, and then mixed and processed with a suitable amount of the SAN resin prepared separately to produce a product having various physical properties to meet the needs of the consumer Various efforts are being made for this purpose.

Accordingly, the present inventors have found that rubber-reinforced styrene-containing graft copolymer resins having a specific average particle diameter of rubber components produced by an industrially advantageous emulsion polymerization method, and two kinds of acrylonitrile contents and weight average molecular weights different from each other. The use of a mixture of SAN resins and various additives such as ethylene bis fatty acid amide has led to the development of thermoplastic resin compositions having excellent impact resistance and fluidity with desirable physical properties that meet the needs of the consumer.

An object of the present invention is to provide a thermoplastic resin composition with improved impact resistance and fluidity.

Another object of the present invention is to provide a resin composition having various physical properties by producing a rubber-reinforced styrenic graft copolymer resin by an emulsion polymerization method.

Another object of the present invention is to provide a thermoplastic resin composition having excellent impact resistance and fluidity by specifying an average particle diameter of rubber which is a component of rubber-reinforced styrenic graft copolymer resin.

Another object of the present invention is to use a mixture of two kinds of SAN resins having different acrylonitrile content and weight average molecular weight, thereby improving the thermoplastic resin composition having improved impact resistance and fluidity by different acrylonitrile content and molecular weight. It is to provide.

Still another object of the present invention is to provide a thermoplastic resin composition having improved flowability, rigidity and impact resistance by adding an additive to the graft copolymer resin and the SAN resin.

The above and other objects of the present invention can be achieved by the following description. Hereinafter, the content of the present invention will be described in detail.

The present invention provides a rubber-reinforced styrene graft copolymer resin containing (A) a rubber having an average particle diameter of 0.1 to 0.4 µm, (B) an acrylonitrile content of 25 to 35% by weight and a weight average molecular weight of 100,000 to 130,000 SAN resin (b ₁₎ 30 to 40% by weight and the acrylonitrile content of the SAN resin and having a weight average molecular weight of 80,000~120,000 (b _2), and (C) an ethylene-bis impact resistance and flexibility comprising a fatty acid amide-improving It provides a thermoplastic resin composition. Hereinafter, the configuration of the present invention in detail.

Each component constituting the resin composition of the present invention is injection molded through a melt kneading process to produce a thermoplastic resin composition having excellent impact resistance and fluidity.

Among the constituents of the present invention, the graft copolymer resin (A) is a graft composed of acrylonitrile and styrene monomer in 45 to 60 parts by weight (based on solids) of rubber latex composed of rubber having an average particle diameter of 0.1 to 0.4 µm. Prepared by grafting 45 to 60 parts by weight of the monomer mixture. In addition, the graft copolymer resin (A) is produced by a conventional emulsion polymerization method. In the present invention, the graft copolymer resin (A) is preferably used in 15 to 40 parts by weight.

If the amount of the graft copolymer resin (A) is less than 15 parts by weight, it is not preferable because the impact resistance is lowered and can be easily broken. If the content of the graft copolymer resin (A) is more than 40 parts by weight, the fluidity drops rapidly and the elastic modulus is lowered. Can not meet.

The component (B) of the present invention has a SAN resin (b ₁ ) having an acrylonitrile content of 25 to 35 wt% and a weight average molecular weight of 100,000 to 130,000, and an acrylonitrile content of 30 to 40 wt% and a weight average molecular weight It is composed of 80,000 to 120,000 SAN resin (b ₂ ), the SAN resin (b ₁ ) is used in 25 to 45 parts by weight and the SAN resin (b ₂ ) is used in 35 to 65 parts by weight. The SAN resins are also prepared by conventional suspension polymerization, emulsion polymerization or bulk polymerization. In the present invention component (B) composed of the SAN resin (b ₁₎ and (b ₂₎ is preferably used from 20 to 80 parts by weight.

In this invention, a thermoplastic resin composition is obtained by mix | blending ethylene bis fatty acid amide (C) with an additive with the said base resin (A) + (B). The ethylene bis fatty acid amide (C) used in the present invention can be obtained by condensation reaction of fatty acids and aliphatic diamines. In the thermoplastic resin composition of the present invention, the component (C) is preferably added in an amount of 3 to 10 parts by weight based on 100 parts by weight of the base resin (A) + (B).

When the input amount of the ethylene bis fatty acid amide (C) is out of the above range, the fluidity, impact resistance and rigidity effect are insufficient.

In the mixing of the graft copolymer resin (A), SAN resin (B) and ethylene bis fatty acid amide (C), a heat stabilizer and / or an external lubricant is further added to prevent oxidation that may occur during extrusion and injection molding. Can be added. The heat stabilizer is a phenolic heat stabilizer or a phosphite heat stabilizer, and the phenolic heat stabilizer is 2,6-di-ti-butyl-4-methylphenol and 2,2'-ethylene-bis (4-methyl- 6-thi-butyl) -phenol, and the like, and phosphite-based heat stabilizers include diphenyl monooctylphosphite. The external lubricant is also selected from the group consisting of metal stearate-based barium stearate, calcium stearate and magnesium stearate.

In the thermoplastic resin composition of the present invention, an ultraviolet stabilizer, an antistatic agent, an antidropping agent, an impact enhancer, an inorganic additive, an antioxidant, a pigment, and / or a dye may be further added according to each use.

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

Examples 1 to 3

Graft copolymer resin (A) having a particle diameter of 0.3 μm, a graft ratio of 65% by weight, a SAN resin (b ₁ ) having an acrylonitrile content of 28% by weight and a weight average molecular weight of 120,000, and an acrylonitrile content It was prepared by mixing to the content shown in Table 1 using ethylene bis fatty acid amide (C) and magnesium stearate (external lubricant) to SAN resin (b ₂ ) of 32% by weight and a weight average molecular weight of 100,000.

Comparative Examples 1-9

A graft copolymer resin having a particle diameter of 0.3 μm, a graft ratio of 65% by weight, a SAN resin (b ₁ ) having an acrylonitrile content of 28% by weight and a weight average molecular weight of 120,000, and an acrylonitrile content of 32% by weight Ethylene bis fatty acid amide (C), magnesium stearate (external lubricant), trioctyl trimellitate (TOTM) (additive 1), adipic glycol in SAN resin (b ₂ ) having a weight average molecular weight of 100,000 In the same manner as in Examples 1 to 3, except that polyester (adiphic acid glycol polyester) (additive 2) and dioctyl adipate (DOA) (additive 3) were added in the amounts shown in Table 1 below. It was done.

division Component (parts by weight) Graft Copolymer (A) SAN resin (B) Ethylene Bis Fatty Acid Amide (C) Magnesium Stearate (external lubricant) Additives 1 Additive 2 Additive 3 (b ₁ ) (b ₂ ) Example One 25 35 40 3.0 0.4 - - - 2 25 35 40 4.0 0.4 - - - 3 25 35 40 5.0 0.4 - - - Comparative Example One 25 35 40 2.0 0.4 1.0 - - 2 25 35 40 2.0 0.4 2.0 - - 3 25 35 40 2.0 0.4 2.0 - - 4 25 35 40 2.0 0.4 - 1.0 - 5 25 35 40 2.0 0.4 - 2.0 - 6 25 35 40 2.0 0.4 - 3.0 - 7 25 35 40 2.0 0.4 - - 1.0 8 25 35 40 2.0 0.4 - - 2.0 9 25 35 40 2.0 0.4 - - 3.0

The same contents as in Examples 1 to 3 and Comparative Examples 1 to 9 were mixed, melted, kneaded and extruded to prepare pellets. At this time, extrusion was performed using a twin screw extruder having a diameter of L / D = 29 and 45 mm, and the cylinder temperature was set at 200 to 230 ° C.

The result of the measurement of the physical properties by injection molding the physical specimen with the prepared pellets is shown in Table 2 below, and the physical properties were measured by the following method.

Notched Izod impact strength was measured at 1/4 ″, 23 ° C. and 1/8 ″, 23 ° C., respectively, according to ASTM D-256, and the useful index was measured at 5 kg, 200 ° C., according to ASTM D-1238. Softening point temperature was measured by 5 kg, 50 ℃ / hr according to ASTM D-1525, and tensile strength was measured by ASTM D-638.

division Properties Notched Izod Impact Strength (1/4 ″) (kgfcm / cm) Notched Izod Impact Strength (1/8 ″) (kgfcm / cm) Flow index (g / 10 min) Thermal softening point temperature (℃) Tensile Strength (kg / ㎠) Example One 19 22 4.4 98.3 440 2 21 26 5.1 96.0 420 3 22 29 5.5 94.0 420 Comparative Example One 18 21 4.0 94.5 460 2 18 21 4.3 93.5 430 3 19 22 4.6 91.4 430 4 18 20 3.9 94.4 465 5 17 20 4.2 94.1 460 6 16 19 5.5 90.4 440 7 18 21 4.1 94.6 430 8 18 20 4.7 92.4 400 9 18 21 5.1 91.1 370

Therefore, when comparing the physical properties of the above Table 2, ethylene bis fatty acid amide is used outside the range of the preferred amount of addition, trioctyl trimellitate (TOTM), adipic glycol glycol or dioctyl adipate (DOA) In the additional comparative example, the flowability was relatively improved, but the impact resistance was not improved.

The present invention characterizes the average particle diameter of rubber, which is a component of rubber-reinforced styrenic graft copolymer resin polymerized by emulsion polymerization, and uses two kinds of SAN resins having different acrylonitrile content and weight average molecular weight. By adding an additive to the graft copolymer resin and the SAN resin, it has the effect of providing a thermoplastic resin composition having improved fluidity, rigidity and impact resistance at the same time.

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)

(A) 15 to 40 parts by weight of rubber-reinforced styrene-based graft copolymer resin containing rubber having an average particle diameter of 0.1 to 0.4 mu m; (B) 25 to 45 parts by weight of a SAN resin (b ₁ ) having an acrylonitrile content of 25 to 35% by weight and a weight average molecular weight of 100,000 to 130,000, and an acrylonitrile content of 30 to 40% by weight and a weight average molecular weight of 80,000 35 to 65 parts by weight of the SAN resin (b ₂ ) which is ˜120,000; And (C) 3 to 10 parts by weight of ethylene bis fatty acid amide based on 100 parts by weight of the base resin (A) + (B); The thermoplastic resin composition with improved impact resistance and fluidity, characterized in that consisting of. The graft copolymer resin (A) is prepared by grafting 45 to 60 parts by weight of a graft monomer mixture composed of acrylonitrile and styrene monomer on a rubber latex, which accounts for 45 to 60 parts by weight based on solids. A thermoplastic resin composition having improved impact resistance and fluidity. The thermoplastic resin composition of claim 1, wherein the component (B) consisting of the SAN resins (b ₁ ) and (b ₂ ) is used in an amount of 20 to 80 parts by weight. The thermoplastic resin composition of claim 1, further comprising an external lubricant and / or a heat stabilizer. The method of claim 4, wherein the external lubricant is selected from a metal stearate compound consisting of barium stearate, calcium stearate and magnesium stearate, and the thermal stabilizer is 2,6-di-thi-butyl-4-methyl A phenolic heat stabilizer of phenol or 2,2'-ethylene-bis (4-methyl-6-ti-butyl) -phenol, or a phosphite heat stabilizer of diphenyl monooctylphosphite; and Thermoplastic resin composition with improved flowability.