Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition comprising: a diene-based graft polymer; a vinyl-based non-graft polymer containing alkyl-substituted vinyl aromatic monomer units and vinyl cyanide-based monomer units; a first maleimide-based non-graft polymer containing maleimide-based monomer units, alkyl-unsubstituted vinyl aromatic monomer units, and vinyl cyanide-based monomer units; and a second maleimide-based non-graft polymer containing maleimide-based monomer units and alkyl-unsubstituted vinyl aromatic monomer units, wherein the first maleimide-based non-graft polymer has a lower glass transition temperature than the second maleimide-based non-graft polymer.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2022-0121698 filed on September 26, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference. The present invention relates to a thermoplastic resin composition. [Background technology]

[0002] The diene graft polymer comprises a diene rubber polymer and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted onto the diene rubber polymer. Compared to existing high-strength polystyrene, the diene graft polymer has excellent impact resistance, chemical resistance, thermal stability, colorability, fatigue resistance, rigidity, and processability. Due to these properties, diene rubber thermoplastic resin molded products made from the diene graft polymer are used as parts for automotive interior and exterior materials, office equipment, and various electrical and electronic products.

[0003] Meanwhile, diene-based thermoplastic resin compositions containing diene-based graft polymers can be used as materials for rear lamp housings, an automotive component. Rear lamp housings can be divided into bulb-type and combined-type. Bulb-type housings can be manufactured by directly depositing aluminum on the housing surface, while combined-type housings can be manufactured by separately manufacturing the internal components and then combining them with the housing. However, due to the structural design of rear lamp housings, in models with high internal heat generation, rear lamp housings can be unable to withstand the heat. This has led to a need for ultra-heat-resistant thermoplastic resin compositions with enhanced heat resistance. However, while currently developed ultra-heat-resistant thermoplastic resin compositions have excellent heat resistance, they are not suitable for bulb-type housings due to the high diffuse reflectance of the aluminum-deposited surface, and their low flow index reduces processability, limiting their use as raw materials for rear lamp housings. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent No. 10-2030120 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a thermoplastic resin composition which has improved processability, impact resistance, heat resistance and aluminum vapor deposition surface properties. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides 1) a thermoplastic resin composition comprising: a diene-based graft polymer; a vinyl-based non-graft polymer comprising alkyl-substituted vinyl aromatic monomer units and vinyl cyanide-based monomer units; a first maleimide-based non-graft polymer comprising maleimide-based monomer units, alkyl-unsubstituted vinyl aromatic monomer units, and vinyl cyanide-based monomer units; and a second maleimide-based non-graft polymer comprising maleimide-based monomer units and alkyl-unsubstituted vinyl aromatic monomer units; wherein the first maleimide-based non-graft polymer has a lower glass transition temperature than the second maleimide-based non-graft polymer.

[0007] 2) The present invention provides the thermoplastic resin composition according to 1), wherein the first non-grafted maleimide polymer has a glass transition temperature that is 10 to 30°C lower than that of the second non-grafted maleimide polymer. 3) The present invention provides the thermoplastic resin composition according to 1) or 2), wherein the first non-grafted maleimide polymer has a glass transition temperature of 165 to 185°C.

[0008] 4) The present invention provides the thermoplastic resin composition according to any one of 1) to 3), wherein the second non-grafted maleimide polymer has a glass transition temperature of 186 to 206°C.

[0009] 5) The present invention provides a thermoplastic resin composition according to any one of 1) to 4), wherein the first non-grafted maleimide polymer is a terpolymer consisting of maleimide monomer units, vinyl aromatic monomer units not substituted with alkyl groups, and vinyl cyanide monomer units.

[0010] 6) The present invention provides a thermoplastic resin composition according to any one of 1) to 5) above, which contains the first non-grafted maleimide polymer in an amount of 7.5 to 16.5% by weight. 7) The present invention provides the thermoplastic resin composition according to any one of 1) to 6), wherein the second non-grafted maleimide polymer is a bipolymer composed of maleimide monomer units and vinyl aromatic monomer units not substituted with an alkyl group.

[0011] 8) The present invention provides a thermoplastic resin composition according to any one of 1) to 7), which contains the second non-grafted maleimide polymer in an amount of 7.5 to 16.5% by weight. 9) The present invention provides a thermoplastic resin composition according to any one of 1) to 8), wherein the diene graft polymer comprises a diene rubber polymer and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

[0012] 10) The present invention provides a thermoplastic resin composition according to any one of 1) to 9), which contains the diene graft polymer in an amount of 22.0 to 30.0% by weight. 11) The present invention provides a thermoplastic resin composition according to any one of 1) to 10), which contains a first diene graft polymer and a second diene graft polymer, the diene rubber polymers having different average particle sizes. 12) The present invention provides a thermoplastic resin composition according to 11), wherein the first diene graft polymer comprises a diene rubber polymer having an average particle size of 50 to 220 nm, and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

[0013] 13) The present invention provides a thermoplastic resin composition according to 11) or 12), wherein the second diene graft polymer comprises a diene rubber polymer having an average particle size of 250 to 500 nm, and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

[0014] 14) The present invention provides a thermoplastic resin composition according to any one of 11) to 13), wherein the weight ratio of the first diene graft polymer to the second diene graft polymer is 1:1.0 to 4.0. 15) The present invention provides a thermoplastic resin composition according to any one of 1) to 14) above, which contains the vinyl-based non-graft polymer in an amount of 45.0 to 53.0% by weight. [Effects of the Invention]

[0015] The thermoplastic resin composition according to the present invention has excellent processability, impact resistance, heat resistance, and aluminum-deposited surface properties, as well as excellent tensile strength and stress, making it suitable for use in rear lamp housings of automobiles where high temperatures are generated, and can also be used as an exterior material for automobiles where high temperatures are generated. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will now be described in more detail to aid in understanding the invention. The terms and words used in this specification and claims should not be interpreted limited to their ordinary and dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concepts of terms in order to best explain his or her invention.

[0017] The "diene rubber polymer" in the present invention may be produced by polymerizing a diene monomer. The diene monomer may be one or more selected from the group consisting of 1,3-butadiene, isoprene, chloroprene, and piperylene, among which 1,3-butadiene is preferred.

[0018] In the present invention, the vinyl aromatic monomer substituted with an alkyl group may be one or more selected from the group consisting of α-methylstyrene, α-ethylstyrene, p-methylstyrene, and 2,4-dimethylstyrene. The unit derived from the "vinyl aromatic monomer substituted with an alkyl group" may be an "alkyl group-substituted vinyl aromatic monomer unit."

[0019] In the present invention, the vinyl aromatic monomer unsubstituted with an alkyl group may be one or more selected from the group consisting of styrene, p-fluorostyrene, p-chlorostyrene, and p-bromostyrene. The unit derived from the "vinyl aromatic monomer unsubstituted with an alkyl group" may be an "vinyl aromatic monomer unit unsubstituted with an alkyl group."

[0020] In the present invention, the vinyl cyanide-based monomer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, (Z)-3-phenylacrylonitrile, and α-chloroacrylonitrile, among which acrylonitrile is preferred. A unit derived from a "vinyl cyanide-based monomer" may be a "vinyl cyanide-based monomer unit."

[0021] In the present invention, the maleimide-based monomer may be one or more selected from the group consisting of maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, 2-methyl-N-phenylmaleimide, N-(4-bromophenyl)maleimide, N-(4-nitrophenyl)maleimide, N-(4-hydroxyphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-carboxyphenyl)maleimide, and N-benzylmaleimide, of which N-phenylmaleimide is preferred. A unit derived from a "maleimide-based monomer" may be referred to as a "maleimide-based monomer unit."

[0022] In the present invention, the weight average molecular weight can be measured as a relative value to that of a polystyrene standard sample via gel permeation chromatography using tetrahydrofuran as an eluent.

[0023] In the present invention, the glass transition temperature can be measured by differential scanning calorimetry.

[0024] In the present invention, the average particle size can be measured using a dynamic light scattering method, specifically, a Nicomp 380 device manufactured by Particle Sizing Systems, Inc. The average particle size in the present invention can refer to the arithmetic mean particle size in the particle size distribution measured by the dynamic light scattering method, i.e., the intensity distribution mean particle size.

[0025] 1.Thermoplastic resin composition A thermoplastic resin composition according to one embodiment of the present invention comprises: 1) a diene-based graft polymer; 2) a vinyl-based non-graft polymer comprising alkyl-substituted vinyl aromatic monomer units and vinyl cyanide-based monomer units; 3) a first maleimide-based non-graft polymer comprising maleimide-based monomer units, alkyl-unsubstituted vinyl aromatic monomer units, and vinyl cyanide-based monomer units; and 4) a second maleimide-based non-graft polymer comprising maleimide-based monomer units and alkyl-unsubstituted vinyl aromatic monomer units; wherein the first maleimide-based non-graft polymer has a lower glass transition temperature than the second maleimide-based non-graft polymer.

[0026] The present inventors have found that when a thermoplastic resin composition contains both a first non-grafted maleimide polymer having a low glass transition temperature and a second non-grafted maleimide polymer having a high glass transition temperature, the impact resistance, aluminum vapor deposition surface properties, and heat resistance are all improved, making the composition suitable for use in automotive rear lamp housings. This discovery led to the completion of the present invention.

[0027] Hereinafter, components of a thermoplastic resin composition according to an embodiment of the present invention will be described in detail. 1) Diene-based graft polymer The diene graft polymer is a component that improves the impact resistance, tensile strength, and stress of a thermoplastic resin composition. The diene graft polymer may include a diene rubber polymer and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer. The cells may also include vinyl aromatic monomer units and vinyl cyanide monomer units that are not grafted to the diene rubber polymer.

[0028] The diene rubber polymer may have an average particle size of 50 to 500 nm, preferably 70 to 470 nm. If the above conditions are met, both the impact resistance and surface properties of the diene graft polymer can be improved.

[0029] The diene graft polymer may be included in an amount of 22.0 to 30.0 wt %, preferably 24.0 to 28.0 wt %, based on the total weight of the thermoplastic resin composition. By satisfying the above conditions, it is possible to impart excellent impact resistance, tensile strength, and stress to the thermoplastic resin composition while minimizing the effect on the processability and heat resistance of the thermoplastic resin composition.

[0030] The diene-based graft polymer may include a first diene-based graft polymer and a second diene-based graft polymer having different average particle diameters of diene-based rubber polymers to improve impact resistance, tensile strength, and stress as well as maximize surface smoothness. The first diene graft polymer may include a diene rubber polymer having an average particle size of 50 to 220 nm, preferably 50 to 150 nm, more preferably 70 to 130 nm, and most preferably 90 to 110 nm, and cells including vinyl aromatic monomer units and vinyl cyanide monomer units grafted onto the diene rubber polymer, each substituted or unsubstituted with an alkyl group. When the average particle size satisfies the above-mentioned conditions, the thermoplastic resin composition may exhibit excellent tensile strength and stress, maximize surface smoothness, and achieve excellent aluminum deposition surface properties.

[0031] The second diene graft polymer may include a diene rubber polymer having an average particle size of 250 to 500 nm, preferably 250 to 400 nm, more preferably 250 to 350 nm, and most preferably 280 to 320 nm, and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted onto the diene rubber polymer, each substituted or unsubstituted with an alkyl group. When the average particle size satisfies the above-mentioned conditions, the thermoplastic resin composition may exhibit better impact resistance.

[0032] On the other hand, when the thermoplastic resin composition is used in an area requiring excellent tensile strength, stress, and surface smoothness, the first diene-based rubber graft polymer may be contained in an excess amount, and when the thermoplastic resin composition is used in an area requiring excellent impact strength, the second diene-based graft polymer may be contained in an excess amount.

[0033] When the thermoplastic resin composition is used for a housing of an automobile rear lamp, the weight ratio of the first diene-based graft polymer to the second diene-based graft polymer may be 1:1.0 to 4.0, preferably 1:2.0 to 3.8, and more preferably 1:3.0 to 3.5. When the above conditions are met, tensile strength, stress, and surface smoothness are improved while minimizing a decrease in impact resistance, and a thermoplastic resin composition more suitable for an automobile rear lamp housing can be produced.

[0034] On the other hand, the diene rubber graft polymer may be a graft polymer obtained by graft polymerizing styrene and acrylonitrile onto a polybutadiene rubber polymer.

[0035] 2) Vinyl-based non-graft polymers The vinyl-based non-grafted polymer is a component that improves the processability, chemical resistance, and heat resistance of the thermoplastic resin composition. The vinyl-based non-graft polymer includes a vinyl aromatic monomer unit substituted with an alkyl group and a vinyl cyanide monomer unit.

[0036] The vinyl-based non-grafted polymer may contain 67 to 75 wt %, preferably 69 to 73 wt %, of alkyl-substituted vinyl aromatic monomer units. When the above conditions are met, the heat resistance of the vinyl-based non-grafted polymer can be improved. The vinyl-based non-grafted polymer may contain 25 to 33 wt %, preferably 27 to 31 wt %, of vinyl cyanide-based monomer units. If the above conditions are met, the chemical resistance of the vinyl-based non-grafted polymer may be improved.

[0037] The weight average molecular weight of the vinyl-based non-grafted polymer may be 80,000 to 120,000 g / mol, preferably 90,000 to 110,000 g / mol. If the above conditions are met, the processability and mechanical properties can be improved.

[0038] The vinyl-based non-grafted polymer may be contained in an amount of 45.0 to 53.0 wt %, preferably 47.0 to 51.0 wt %, based on the total weight of the thermoplastic resin. By satisfying the above conditions, the thermoplastic resin composition can be provided with excellent processability, chemical resistance, and heat resistance.

[0039] 3) First maleimide-based non-graft polymer The first maleimide-based non-graft polymer is a component that improves impact resistance, tensile strength, processability, and aluminum vapor deposition surface properties through synergy with the diene-based graft polymer.

[0040] The first maleimide-based non-grafted polymer contains maleimide-based monomer units, alkyl-unsubstituted vinyl aromatic monomer units, and vinyl cyanide-based monomer units. Because the first maleimide-based non-grafted polymer contains alkyl-unsubstituted vinyl aromatic monomer units and vinyl cyanide monomer units, it has excellent compatibility with the diene-based grafted polymer and vinyl-based non-grafted polymer. As a result, the synergy between the diene-based grafted polymer and the vinyl-based non-grafted polymer can improve impact resistance, tensile strength, processability, and aluminum-deposited surface properties.

[0041] The first non-grafted maleimide polymer has a lower glass transition temperature than the second non-grafted maleimide polymer described below. When the above conditions are met, the impact resistance and aluminum vapor deposition surface properties are improved compared to when the first non-grafted maleimide polymer is not included, and the heat resistance is improved compared to when the second non-grafted maleimide polymer is not included.

[0042] The first non-grafted maleimide polymer may have a glass transition temperature that is lower by 10 to 30° C., preferably 15 to 25° C., than the second non-grafted maleimide polymer described below. When the above conditions are met, it is possible to minimize the degradation of the impact resistance and aluminum-deposited surface properties of the thermoplastic resin composition due to the second non-grafted maleimide polymer, and to minimize the degradation of heat resistance due to the first non-grafted maleimide polymer.

[0043] Meanwhile, the first maleimide-based non-grafted polymer may have a glass transition temperature of 165 to 185°C, preferably 170 to 180°C. By satisfying these conditions, the first maleimide-based non-grafted polymer may contain a relatively small amount of maleimide-based monomer units, which improve heat resistance, and a relatively large amount of unsubstituted alkyl aromatic vinyl-based monomer units and vinyl cyanide-based monomer units, which improve compatibility between the diene-based grafted polymer and the vinyl-based non-grafted polymer. The improved compatibility between the first maleimide-based non-grafted polymer, the diene-based grafted polymer, and the vinyl-based non-grafted polymer may further improve impact resistance and aluminum-deposited surface properties. Furthermore, the heat resistance of the thermoplastic resin composition may be improved, allowing the thermoplastic resin composition to be used for automotive rear lamp housings.

[0044] The first non-grafted maleimide polymer may have a weight-average molecular weight of 125,000 to 155,000 g / mol, preferably 130,000 to 150,000 g / mol. If the above conditions are met, the weight-average molecular weights of the vinyl non-grafted polymer and the second non-grafted maleimide polymer will be similar, which may improve the compatibility between them.

[0045] The first non-grafted maleimide polymer may be a terpolymer including a maleimide monomer unit, a vinyl cyanide monomer unit, and an alkyl-unsubstituted vinyl aromatic monomer unit, specifically, an N-phenylmaleimide / styrene / acrylonitrile polymer.

[0046] The first maleimide-based non-grafted polymer may be included in an amount of 7.5 to 16.5 wt %, preferably 10.0 to 15.0 wt %, based on the total weight of the thermoplastic resin composition. When the above conditions are met, the impact resistance and aluminum-deposited surface properties of the thermoplastic resin composition can be improved while minimizing the decrease in tensile strength and stress.

[0047] 4) Second maleimide-based non-graft polymer The second non-grafted maleimide polymer is a component that improves the heat resistance of the thermoplastic resin composition. The second non-grafted maleimide polymer contains maleimide monomer units and vinyl aromatic monomer units not substituted with alkyl groups. Because the second non-grafted maleimide polymer contains maleimide monomer units and vinyl cyanide monomer units, it has excellent compatibility with the first non-grafted maleimide polymer. As a result, the synergy between the first and second non-grafted maleimide polymers significantly improves heat resistance.

[0048] The second non-grafted maleimide polymer may have a glass transition temperature of 186 to 206° C., preferably 191 to 201° C. If the above conditions are satisfied, the heat resistance of the thermoplastic resin composition can be significantly improved.

[0049] The second non-grafted maleimide polymer may be a bipolymer consisting of a maleimide monomer unit and a vinyl aromatic monomer unit unsubstituted with an alkyl group, specifically, an N-phenylmaleimide / styrene polymer.

[0050] The second maleimide-based non-grafted polymer may be included in an amount of 7.5 to 16.5 wt %, preferably 10.0 to 15.0 wt %, based on the total weight of the thermoplastic resin composition. By satisfying the above conditions, the heat resistance of the thermoplastic resin composition can be improved while minimizing deterioration in processability, impact resistance, tensile strength, and stress.

[0051] DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with reference to exemplary embodiments thereof so that those skilled in the art can easily understand and practice the invention. However, the present invention may be embodied in many different forms and is not limited to the exemplary embodiments set forth herein.

[0052] Examples and Comparative Examples The components used in the following examples and comparative examples are described below.

[0053] First diene graft polymer: DP229M from LG Chemical Co., Ltd. (containing a polybutadiene rubber polymer having an average particle size of 100 nm and cells containing styrene units and acrylonitrile units grafted onto the polybutadiene rubber polymer)

[0054] Second diene graft polymer: DP270E from LG Chemical Co., Ltd. (containing a polybutadiene rubber polymer having an average particle size of 300 nm and cells containing styrene units and acrylonitrile units grafted onto the polybutadiene rubber polymer)

[0055] Vinyl non-graft polymer: LG Chemical's 200UH (a weight-average molecular weight of 100,000 g / mol, an α-methylstyrene / acrylonitrile non-graft polymer produced by polymerizing 71% by weight of α-methylstyrene and 29% by weight of acrylonitrile)

[0056] SAN polymer: LG Chemical's 95RF (a styrene / acrylonitrile non-graft polymer with a weight average molecular weight of 100,000 g / mol, produced by polymerizing 71% by weight of styrene and 29% by weight of acrylonitrile)

[0057] First maleimide-based non-graft polymer: IPX-02 manufactured by DENKA Corporation (a non-graft N-phenylmaleimide / styrene / acrylonitrile polymer having a weight average molecular weight of 140,000 g / mol and a glass transition temperature of 175°C)

[0058] First maleimide-based non-graft polymer: IPX-02 manufactured by DENKA Corporation (N-phenylmaleimide / styrene / acrylonitrile terpolymer having a weight average molecular weight of 140,000 g / mol and a glass transition temperature of 175°C) Second maleimide-based non-graft polymer: MS-NB (N-phenylmaleimide / styrene copolymer with a weight-average molecular weight of 140,000 g / mol and a glass transition temperature of 196°C) manufactured by DENKA Corporation

[0059] The above-mentioned components were mixed and stirred in the amounts shown in Tables 1 and 2 below to prepare thermoplastic resin compositions.

[0060] Experimental Example 1 The thermoplastic resin compositions of the Examples and Comparative Examples were extruded to prepare pellets, and the pellets were evaluated by the methods described below. The results are shown in Tables 1 and 2 below. (1) Melt Flow Index (g / 10 min): Measured under conditions of 220°C and 10 kg according to ASTM D1238. In the present invention, a melt flow index of 3.0 g / 10 min or more was determined to be excellent in processability.

[0061] Experimental Example 2 The thermoplastic resin compositions of the examples and comparative examples were extruded and injected to prepare test specimens, which were then evaluated according to the methods described below. The results are shown in Tables 1 and 2 below. (2) Izod impact strength (kg·cm / cm, 1 / 4 inch): Measured according to ASTM D256. In the present invention, an Izod impact strength of 9.0 kg·cm / cm or more was determined to be excellent in impact resistance. (3) Tensile strength (kg / cm 2 ) and tensile elongation rate (%): Measured according to ASTM D638. In the present invention, the tensile strength is 440 kg / cm 2 As described above, when the tensile elongation rate is 40% or more, it is determined that the tensile strength is excellent. (4) Flexural strength (kg / cm2 ): Measured based on ASTM D790. In the present invention, the bending strength is 650 kg / cm 2 If the value was equal to or greater than this, it was determined that the stress was excellent. (5) Heat Deflection Temperature (°C): Measured under unanealed conditions according to ASTM D648. In the present invention, a heat distortion temperature of 109°C or higher was determined to be excellent in heat resistance.

[0062] Experimental Example 3 The thermoplastic resin compositions of the Examples and Comparative Examples were extruded and injected to prepare 10 cm x 10 cm specimens, and aluminum was vacuum-deposited on the surfaces using a vacuum deposition device (product name: high vacuum deposition device, manufacturer: Daehan Vacuum Engineering). The physical properties of the specimens with aluminum films formed thereon were measured using the following methods, and the results are shown in Tables 1 and 2. (6) Diffuse reflectance (%): Diffuse reflectance was measured using a surface gloss measuring device (TOKYO DENSHOKU's Reflectometer (TR-1100AD)). Here, since the diffuse reflectance is significantly affected by the sensitivity of the gas and surface characteristics, the condition of the vacuum deposition surface can be inferred from the diffuse reflectance. In the present invention, a diffuse reflectance of 6.0% or less was determined to be excellent in the condition of the vacuum deposition surface.

[0063] Experimental Example 4 The thermoplastic resin compositions of the examples and comparative examples were extruded and injected to prepare test pieces of 10 cm x 10 cm x 3 cm, and the physical properties were measured as follows. The results are shown in Tables 1 and 2 below. (7) Whether cracks occurred due to hammer strikes: The same part of the fixed specimen was struck 10 times with a rubber hammer, and whether cracks occurred was confirmed. (8) Crack occurrence due to ball drop: The occurrence of cracks was confirmed using a ball drop device with a 5 kg ball. The ball drop device is a free fall testing device in which the ball is fixed at a certain height using a magnet, and then the magnetic force is removed and the ball is allowed to fall freely. The height was adjusted in 10 cm intervals to increase the force applied to the specimen, and the occurrence of cracks was evaluated. ×: No cracks occurred, ○: Cracks occurred

[0064] [Table 1]

[0065] [Table 2]

[0066] Referring to Tables 1 and 2, Examples 1 to 6 all had appropriate flow index, impact strength, tensile strength, tensile elongation, flexural strength, heat distortion temperature, and diffuse reflectance, and no cracks were observed when struck with a hammer or dropped. These results demonstrate that Examples 1 to 6 are excellent in processability, impact resistance, tensile strength, stress, heat resistance, and aluminum vapor deposition surface properties.

[0067] Referring to Examples 1 to 3 in which the total amount of the first maleimide-based non-grafted polymer and the second maleimide-based non-grafted polymer was the same but the weight ratio between them was varied, it was found that the impact resistance, tensile strength, stress, and aluminum deposition surface properties improved as the content of the first maleimide-based non-grafted polymer increased, and the heat resistance improved as the content of the second maleimide-based non-grafted polymer increased.

[0068] In Examples 2, 4, and 5, in which the weight ratio of the first maleimide-based non-grafted polymer to the second maleimide-based non-grafted polymer was 1:1 but the sum of these polymers was varied, the tensile strength, flexural strength, and heat distortion temperature increased as the sum of the first and second maleimide-based non-grafted polymers increased, while the flow index and diffuse reflectance decreased as the sum of the first and second maleimide-based non-grafted polymers decreased. These results indicate that the tensile strength, stress, and heat resistance improved as the sum of the first and second maleimide-based non-grafted polymers increased. Furthermore, the processability and aluminum surface deposition properties improved as the sum of the first and second maleimide-based non-grafted polymers decreased. Furthermore, in Examples 2, 4, and 5, the heat distortion temperature was found to be more affected by the content of the second maleimide-based non-grafted polymer than by the content of the vinyl-based non-grafted polymer.

[0069] On the other hand, Comparative Example 1, which contained a styrene / acrylonitrile non-grafted polymer instead of an α-methylstyrene / acrylonitrile non-grafted polymer, had low tensile strength, tensile elongation, flexural strength, and heat distortion temperature. These results indicate that Comparative Example 1 has reduced tensile strength, stress, and heat resistance.

[0070] Comparative Example 2, which did not contain the first non-grafted maleimide polymer, had high tensile strength but low tensile elongation, a low heat distortion temperature, and cracks occurred when struck with a hammer and dropped onto a ball. These results indicate that Comparative Example 2 had reduced tensile strength, heat resistance, and impact resistance.

[0071] Comparative Example 3, which did not contain the second maleimide-based non-grafted polymer, had low flow index and impact strength, high tensile strength but low tensile elongation, high diffuse reflectance, and cracks occurred when hit with a hammer and when dropped. These results indicate that Comparative Example 3 had reduced processability, impact resistance, tensile strength, and aluminum-deposited surface properties.

Claims

1. Diene graft polymers; a vinyl-based non-graft polymer containing an alkyl-substituted vinyl aromatic monomer unit and a vinyl cyanide monomer unit; a first maleimide-based non-grafted polymer containing maleimide-based monomer units, vinyl aromatic-based monomer units not substituted with alkyl groups, and vinyl cyanide-based monomer units; and a second maleimide-based non-grafted polymer comprising maleimide-based monomer units and vinyl aromatic-based monomer units not substituted with alkyl groups; A thermoplastic resin composition, wherein the first non-grafted maleimide polymer has a lower glass transition temperature than the second non-grafted maleimide polymer.

2. The thermoplastic resin composition according to claim 1 , wherein the first non-grafted maleimide polymer has a glass transition temperature that is 10 to 30° C. lower than that of the second non-grafted maleimide polymer.

3. The thermoplastic resin composition according to claim 2 , wherein the first non-grafted maleimide polymer has a glass transition temperature of 165 to 185° C.

4. The thermoplastic resin composition according to claim 2 , wherein the second non-grafted maleimide polymer has a glass transition temperature of 186 to 206° C.

5. 2. The thermoplastic resin composition according to claim 1, wherein the first non-grafted maleimide polymer is a terpolymer consisting of maleimide monomer units, vinyl aromatic monomer units not substituted with alkyl groups, and vinyl cyanide monomer units.

6. 2. The thermoplastic resin composition according to claim 1, wherein the first non-grafted maleimide polymer is contained in an amount of 7.5 to 16.5 wt. %.

7. 2. The thermoplastic resin composition according to claim 1, wherein the second non-grafted maleimide polymer is a bipolymer comprising a maleimide monomer unit and a vinyl aromatic monomer unit not substituted with an alkyl group.

8. 2. The thermoplastic resin composition according to claim 1, wherein the second non-grafted maleimide polymer is contained in an amount of 7.5 to 16.5 wt %.

9. 2. The thermoplastic resin composition according to claim 1, wherein the diene graft polymer comprises a diene rubber polymer and cells containing vinyl aromatic monomer units and vinyl cyan monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

10. 2. The thermoplastic resin composition according to claim 1, wherein the diene graft polymer is contained in an amount of 22.0 to 30.0 wt %.

11. 2. The thermoplastic resin composition according to claim 1, comprising a first diene graft polymer and a second diene graft polymer, the diene rubber polymers having different average particle sizes.

12. 12. The thermoplastic resin composition according to claim 11, wherein the first diene graft polymer comprises a diene rubber polymer having an average particle size of 50 to 220 nm, and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

13. 12. The thermoplastic resin composition according to claim 11, wherein the second diene graft polymer comprises a diene rubber polymer having an average particle size of 250 to 500 nm, and cells containing vinyl aromatic monomer units and vinyl cyanide monomer units grafted to the diene rubber polymer, each substituted or unsubstituted with an alkyl group.

14. The thermoplastic resin composition according to claim 11, wherein the weight ratio of the first diene graft polymer to the second diene graft polymer is 1:1.0 to 4.

0.

15. 2. The thermoplastic resin composition according to claim 1, wherein the non-grafted vinyl polymer is contained in an amount of 45.0 to 53.0% by weight.

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