KR20020044387A - Thermoplastic Resin Composition Having Excellent Heat Stability and Ultraviolet Stability - Google Patents

Abstract

PURPOSE: Provided is a thermoplastic resin composition excellent in thermal stability and light stability, comprising hindered phenolic antioxidant, phosphite based antioxidant, hals based UV stabilizer, and stearate based metal salt, in addition to base resin. CONSTITUTION: The composition comprises a base resin consisting of (a) 10-60 parts by weight of styrene-based graft copolymer resin having average particle diameter of 0.10-0.40 micrometer, (b) 20-80 parts by weight of styrene-acrylonitrile(SAN) resin containing 20-40 wt% of acrylonitrile and having a weight average molecular weight of 100,000-140,000, and (c) 20-80 parts by weight of SAN resin containing 25-35 wt% of acrylonitrile and having a weight average molecular weight of 80,000-110,000(wherein, (a)+(b)+(c) = 100 parts by weight); (d) 0.05-2 parts by weight of hindered phenolic compound; (e) 0.05-4 parts by weight of phosphite based compound; (f) hals compound; and (g) 0.1-3.0 parts by weight of barium stearate.

Description

Thermoplastic Resin Composition Having Excellent Heat Stability and Ultraviolet Stability}

Field of invention

The present invention relates to a thermoplastic resin composition excellent in thermal stability and light stability. More specifically, the present invention is a styrene-acrylonitrile copolymer (hereinafter referred to as 'SAN resin') prepared separately from the graft copolymer (acrylonitrile-butadiene-styrene copolymer) prepared by the emulsion graft polymerization method. In the process of mixing, SAN resins with different monomer composition and molecular weight distribution are used as the matrix, and specific hindered phenolic antioxidants, phosphite antioxidants, Hals light stabilizers and metal stearate lubricants are used. It relates to a thermoplastic resin composition excellent in thermal stability and light stability prepared by combining.

Background of the Invention

Acrylonitrile-butadiene-styrene (ABS) copolymer resins are prepared by graft polymerization of styrene monomers, which are aromatic vinyl compounds, and acrylonitrile monomers, which are unsaturated nitrile compounds, in the presence of butadiene-based rubbery polymers. At this time, the desired resin was obtained by controlling the physical properties of the rubbery polymer, graft polymer, and matrix polymer used. The ABS resin thus prepared is widely used in parts of electric and electronic products, automobile parts, and general merchandise because of excellent impact resistance, chemical resistance, chemical resistance, heat resistance, mechanical strength, and easy molding process.

ABS resins are generally produced by block polymerization, block polymerization, suspension polymerization, emulsion polymerization, etc., and are produced singly or mixed. However, the graft copolymer resin prepared by the bulk polymerization cannot be manufactured to have various physical properties, and in particular, a resin having a high rubber content cannot be manufactured in spite of advantages such as mass production and reduction in manufacturing cost. Therefore, the most commonly used polymerization method is emulsion polymerization. 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 initiator and redox initiator to acrylonitrile and styrene monomer. To graft polymerization. Then, fine powder is obtained through a solidification, dehydration, and drying process, and a copolymer resin is prepared by mixing and processing a separately prepared SAN resin with an appropriate amount. At this time, by adjusting the rubber particle size, rubber content, rubber particle distribution in the resin, acrylonitrile content, molecular weight, etc. of the SAN resin used, and by adding a variety of additives can be produced a product having a variety of physical properties to meet the needs of the consumer.

However, general ABS resin is degraded by external physical or chemical influence during extrusion processing or injection molding processing, or the color of the product becomes dark and yellow as heat oxidation reaction occurs, and silver streaks are formed on the surface to make normal products. Sometimes it is difficult to use. An antioxidant is added to reduce and prevent the oxidative decomposition reaction of the ABS resin. Such antioxidants include hindered phenol-based, secondary aromatic amine-based, and phosphite-based and thioester-based, which are classified as primary antioxidants. Each of the antioxidants shows good thermal stability, but synergistic effects can be obtained by using two or more in combination. However, even when these antioxidants are used in combination, a large shear stress and heat are generated in the resin during the extrusion and injection molding processes due to the recent trend of thinning and large-sized moldings, so it is normal products due to appearance defects such as discoloration of resin and gas silver. Difficult to use

In addition, butadiene in the ABS resin is poor in weather resistance and when exposed to the outside for a long time to start the photooxidation reaction by the light energy, the resin is decomposed and discoloration occurs, the light stability is inferior.

Therefore, there is an urgent need for the development of ABS resins that are stable to heat and light.

The present inventors use graft copolymer resin prepared by emulsion polymerization method and use a mixture of SAN resins having different acrylonitrile content and molecular weight among SAN resins used as a matrix, and use specific hindered phenolic antioxidants, Peat-based antioxidants, Halus-based UV stabilizers, and stearate-based metal salts were added to prepare thermoplastic resins having excellent thermal stability and light stability.

An object of the present invention is a hindered phenol-based antioxidant and a phos- sized hindered phenol-based antioxidant to a graft copolymer resin prepared by an emulsion polymerization method and a SAN resin having a different acrylonitrile content and molecular weight among SAN resins used as a matrix. The present invention provides a thermoplastic resin composition having excellent thermal stability by adding a fighter antioxidant, a Halus ultraviolet stabilizer, and a stearate metal salt.

Another object of the present invention is a hindered phenolic antioxidant to a base resin in which graft copolymer resin prepared by emulsion polymerization method and SAN resin having different molecular weights and acrylonitrile among SAN resins used as a matrix are mixed; The present invention provides a thermoplastic resin composition excellent in light stability by adding a phosphite antioxidant, a Halus ultraviolet stabilizer, and a stearate metal salt.

Another object of the present invention is to provide a SAN thermoplastic resin having a good appearance.

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 present invention is SAN resin (B) having 10 to 60 parts by weight of graft copolymer resin (A) having an average particle diameter of 0.10 to 0.40 µm and an acrylonitrile content of 20 to 40% by weight and a weight average molecular weight of 100,000 to 140,000. Basic resin (A) + (B) + (C) 100 consisting of 20 to 80 parts by weight of SAN resin (C) having 20 to 80 parts by weight and acrylonitrile content of 25 to 35% by weight and a weight average molecular weight of 80,000 to 110,000. 0.05 to 2 parts by weight of a hindered phenol compound as parts by weight and a primary antioxidant, 0.05 to 4 parts by weight of a phosphite compound as a secondary antioxidant, and 0.3 to 1.0 parts by weight of a Hals compound; It relates to a thermoplastic resin composition having excellent thermal stability and light stability, comprising 0.1 to 3.0 parts by weight of barium stearate.

The base resin composed of (A), (B), and (C) is 5 to 40% by weight of acrylonitrile, 5 to 30% by weight of butadiene, and 20 to 80% by weight of styrene.

Hereinafter, the component of resin is demonstrated in detail.

Hindered phenolic systems used as primary antioxidants are commercialized and commonly used products can be used. In particular, in the present invention, octadiyl-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate (Octadeeyl-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate), tetrabis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (Tetrabis [methylene-3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate] methane), or 1,3,5-tri-methyl-2,4,6, -tri (3,5-di-tert-butyl-4-hydroxybenzyl) benzene (1,3 , 5-Tri-methyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene) and the like can be used. The primary antioxidant is used 0.05 to 2 parts by weight based on 100 parts by weight of the base resin. When less than 0.05 parts by weight is used, there is no sufficient thermal stability effect on the resin, and when it is used in excess of 2 parts by weight, it is not preferable because it is a gas generating factor.

As the secondary antioxidant, thioester compounds and phosphite compounds may be mainly used. In the present invention, triphenyl phosphite, tri (monyl phenyl) phosphite, triisodecyl phosphite, diphenyl-iso-octyl-phosphite (diphenyl-) iso-octyl-phosphite). The secondary antioxidant is used 0.05 to 4 parts by weight based on 100 parts by weight of the base resin. If less than 0.05 parts by weight is used, sufficient thermal stability effect cannot be obtained, and if it is more than 4 parts by weight, it is not preferable because it is a gas generating factor.

In the present invention, in order to increase the light stability, paints, carbon black, metal oxides, etc. which directly block external ultraviolet rays are used, or benzotriazole, benzophenone-based, and Hals-based compounds that absorb ultraviolet rays in the polymer surface or substrate. Compounds can be used. Of these, a bis (2,2,6,6, -tetramethyl-4-piperidinyl) sebacate (halus-based compound) is preferred (bis (2,2,6,6, -tertramethyl-4-piperidinyl) sebacate) Do. The compound uses 0.3 to 1.0 parts by weight based on 100 parts by weight of the base resin. When less than 0.3 part by weight, the light stability is lowered. If it exceeds 1.0 part by weight, thermal stability and gas generation problems are caused.

Barium stearate, which is a metal salt stearate-based lubricant, is used as an additive for preventing adhesion between the mold surface, the surface of the extruder, and the resin and improving slip properties. The barium stearate is kneaded with the resin to lower the melt viscosity, thereby improving the molding processability, the processing temperature is lowered and the processing time is shortened, thereby reducing the loss due to heat during processing. Barium stearate is applied in an amount of 0.1 to 3.0 parts by weight, and the barium content is suitably about 19 to 21% by weight. When barium stearate is added in an amount less than 0.1 part by weight, the activity is lowered, resulting in a decrease in thermal stability and strength. When the content of the barium stearate is more than 3.0 parts by weight, the physical balance of the resin composition is not good.

In order to increase thermal stability and light stability, antioxidants are generally selected according to the resin to be applied, synthesis and processing method, and application purpose. If two or more antioxidants are used, synergistic effect can be expected as a complementary action. A synergistic effect occurs when a hindered phenol compound, a secondary aromatic amine compound, and a thioester compound and a phosphite compound, which are classified as secondary antioxidants, are used as primary antioxidants. In order to achieve such an effect and to improve photostability, a benzotriazole-based light stabilizer or a Hals-based light stabilizer may be used in combination. However, Hals-based light stabilizers are known to reduce the effects when used in combination with other light stabilizers.

In the present invention, a thermoplastic resin having excellent thermal stability and light stability can be produced by using a hindered phenolic antioxidant, a phosphite antioxidant, a Halus ultraviolet stabilizer, and a stearate metal salt in combination. Therefore, the resin according to the present invention has excellent characteristics of processing stability by reducing discoloration during injection molding or thermoforming.

The thermoplastic resin of the present invention may be added with an antistatic agent, an impact modifier, an inorganic additive, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, and a dye according to each use. These may be used within the range of 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 purposes of illustration of the invention and are not intended to suggest protection scope defined by the appended claims.

Example

Examples 1-4

ABS graft copolymer resin (A) having a rubber particle diameter of 0.3 µm and a graft ratio of 65% by weight, SAN resin (B) having an acrylonitrile content of 28% by weight and a weight average molecular weight of 120,000, and an acrylonitrile content Hindered phenolic antioxidant, phosphite antioxidant, Halus-based UV stabilizer, and stearate-based metal salt were added to SAN resin (C) having 28% by weight and a weight average molecular weight of 90,000. Added. Octadyl-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate (IRGANOX 1076) (D) was used as a hindered phenolic antioxidant. For example, diphenyl-iso-octyl-phosphite (E) was used, and a halogen-based UV stabilizer was bis (2,2,6,6, -tetramethyl-4-piperidinyl) sebacate (TINNUVIN 770) (F ) Was used. As the stearate metal salt, barium stearate (G ₁ ) was used. 1.0 part by weight of wax was added thereto, followed by melting and kneading extrusion to prepare pellets. The extrusion was performed using a twin screw extruder having a diameter of L / D = 29, 45 mm and the cylinder temperature was set to 210 ℃. The physical properties of the prepared pellets were measured by injection molding, and the results are shown in Table 2 below.

The measuring method of each physical property is as follows.

Notched Izod impact strength was measured according to ASTM D256 (1/4 ", 23 ° C) and flow index was measured according to ASTM D1238 (5 kg, 200 ° C).

Thermal stability is formed by molding a specimen into a family property mold in a 10 oz injection machine, manufacturing the molded specimen to 100 mm × 100 mm × 3 mm, and staying in a gear oven for 20 minutes, then using a color difference meter (△ E). ) Was measured. The temperature of the gear oven was 200 ° C.

The appearance evaluation was observed in the gear oven after 20 minutes to prepare a 100 mm × 100 mm × 3 mm specimens visually.

Light resistance was measured by the color difference meter (ΔE) with respect to the specimen after 300 hours by ASTM D4459.

Comparative Examples 1 to 4

The content of the constituents was changed as shown in Table 1 and was carried out in the same manner as in Example, except that magnesium stearate (G ₂ ) was used as the stearate-based metal salt. Physical properties of the prepared pellets were injection molded to measure physical properties in the same manner as in Example, and the results are shown in Table 2 below.

ingredient Example Comparative Example One 2 3 4 One 2 3 4 A 30 30 30 30 30 30 30 30 B 25 25 25 25 25 25 25 25 C 45 45 45 45 45 45 45 45 D 0.1 0.2 0.2 0.5 0.1 0.2 0.2 0.5 E 0.1 0.2 0.4 0.5 0.1 0.2 0.4 0.5 F 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 G G ₁ 0.3 0.3 0.3 0.3 - - - - G ₂ - - - - 0.3 0.3 0.3 0.3

Properties Example Comparative Example One 2 3 4 One 2 3 4 Impact strength 30 3031 31 30 30 30 31 32 Flow index 3.0 3.0 3.1 3.2 3.0 3.2 3.2 3.3 Thermal stability 1.28 0.89 0.53 0.26 1.47 1.32 1.18 1.00 Appearance Evaluation ^* △ O O O × △ △ △ Light resistance 1.75 1.55 1.46 1.42 1.89 1.76 1.72 1.70

* O: good, △: normal, x: poor

As shown in Table 2, the case of using the barium stearate as a stearate-based metal salt when the content of the other components are the same as compared to the case of the comparative example using magnesium stearate, the thermal stability and light stability was excellent evaluation The results were also good.

The present invention is a monomer composition and molecular weight distribution of the SAN resin used as a matrix in mixing and processing the graft copolymer (acrylonitrile-butadiene-styrene copolymer) prepared separately by the emulsion graft polymerization method Thermoplastic resin composition with good thermal stability, good light stability and good appearance by combining different SAN resins with specific hindered phenolic antioxidants, phosphite antioxidants, Hals light stabilizers and metal stearate lubricants Has the effect of providing.

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) 10 to 60 parts by weight of styrene graft copolymer resin having an average particle diameter of 0.10 to 0.40 µm, (B) 20 to 80 parts by weight of a styrene-acrylonitrile (SAN) resin having an acrylonitrile content of 20 to 40% by weight and a weight average molecular weight of 100,000 to 140,000, and (C) 20 to 80 parts by weight of a SAN resin having an acrylonitrile content of 25 to 35% by weight and a weight average molecular weight of 80,000 to 110,000; Basic resin consisting of (A) + (B) + (C) 100 parts by weight; (D) 0.05 to 2 parts by weight of the hindered phenol compound; (E) 0.05 to 4 parts by weight of the phosphite compound; (F) 0.3 to 1.0 parts by weight of a Hals-based compound; And (G) 0.1 to 3.0 parts by weight of barium stearate; A thermoplastic resin composition excellent in thermal stability and light stability, characterized in that consisting of. The thermoplastic resin composition according to claim 1, wherein the base resin comprises 5 to 40 wt% of acrylonitrile, 5 to 30 wt% of butadiene, and 20 to 80 wt% of styrene. The method of claim 1, wherein the hindered phenolic compound is octadil-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate, tetrabis [methylene-3- (3,5) -Di-tert-butyl-4-hydroxyphenyl) propionate] methane, and 1,3,5-tri-methyl-2,4,6, -tri (3,5-di-tert-butyl-4 -Hydroxybenzyl) benzene; The phosphite-based compound is selected from the group consisting of triphenyl phosphite, tri (monyl phenyl) phosphite, triisodecyl phosphite, and diphenyl-iso-octyl-phosphite; And, the Hals-based compound is a bis (2,2,6,6, -tetramethyl-4-piperidinyl) sebacate thermoplastic resin composition, characterized in that. The antistatic agent according to any one of claims 1 to 3. A thermoplastic resin composition further comprising a plasticizer, a heat stabilizer, an antioxidant, a light stabilizer, a compatibilizer, a pigment and / or a dye, and an inorganic additive.