Thermoplastic resin composition, method for preparing same, and molded article

Abstract

The present invention relates to a thermoplastic resin composition, a method for preparing the same, and a molded article comprising the same. More specifically, the present invention relates to a thermoplastic resin composition comprising 100 parts by weight of a base resin, the base resin contains 46% to 81% by weight of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm, and 19% to 54% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (B) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm, a copolymer (B) containing 10% by weight or more and less than 26% by weight of a vinyl cyanide compound and having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol; and 3 parts by weight or more of a thermoplastic polyester elastomer (C), wherein the thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65% by weight or more as calculated by Equation 1. According to the present invention, the present invention has the following effects: providing a thermoplastic resin composition having excellent mechanical properties, processability and weather resistance; an attractive appearance can be provided even in a thick sheet due to excellent low whitening characteristics; the device is suitable for non-painted sheets; the present invention relates to a thermoplastic resin composition, and thus has excellent economical efficiency and eco-friendliness, and provides a method for preparing the thermoplastic resin composition and a molded article comprising the same.

Description

Technical Field

[0001] [Cross - Reference to Related Applications]

[0002] This application claims the priority of Korean Patent Application No. 10 - 2023 - 0139390, filed with the Korean Intellectual Property Office on October 18, 2023, and Korean Patent Application No. 10 - 2024 - 0114660, filed with the Korean Intellectual Property Office on August 26, 2024, based on the priority of the above - mentioned patent, the disclosures of which are incorporated herein by reference in their entireties.

[0003] The present invention relates to a thermoplastic resin composition, a method for preparing the same, and a molded article including the same. More specifically, the present invention relates to a thermoplastic resin composition having excellent mechanical properties, weather resistance, processability, and low whitening characteristics; having an aesthetic appearance; being suitable for unpainted molded articles; and thus having excellent economic efficiency and eco - friendliness, a method for preparing the thermoplastic resin composition, and a molded article including the thermoplastic resin composition. Background Art

[0004] Generally, an acrylonitrile - styrene - acrylate copolymer (hereinafter referred to as "ASA resin") containing (meth) acrylic acid alkyl ester compounds does not contain vinyl unsaturated bonds and thus has excellent properties such as processability, impact resistance, chemical resistance, and weather resistance. Therefore, ASA resins have been used in various fields, including building materials, interior and exterior materials of vehicles including automobiles and motorcycles, electrical and electronic products, ships, leisure goods, and gardening goods. In addition, the demand for ASA resins is increasing rapidly.

[0005] In addition, as the market demand for emotional quality and aesthetic level from consumers increases, products having a luxurious appearance, excellent colorability, and weather resistance are being realized by surface - treating the outer surfaces of materials such as ABS, PVC, and iron plates with ASA resins. These finishing materials are manufactured in the form of films and are formed into final products through bending processes such as bending or folding according to the shape of the substrate.

[0006] However, due to the characteristics of thermoplastic ASA resins, when the above - mentioned surface treatment is performed at room temperature, a whitening phenomenon occurs, resulting in the loss of the original color and deterioration of the appearance quality. This whitening phenomenon occurs due to pores in the ASA resin, and as the thickness of the film or sheet increases, the whitening phenomenon becomes more severe.

[0007] In addition, in the furniture and building decoration material markets, there has been a continuous demand for unpainted molded articles due to their environmental friendliness and low production cost. In addition, in order to improve the covering power of the substrate and to conceal external defects such as foreign substances and non-uniformities of the underlying substrate, the demand for thick sheets is increasing.

[0008] Therefore, there is a need to develop a material having excellent processability and mechanical properties, which has low whitening characteristics despite its large thickness and which can provide environmental friendliness and an aesthetic appearance when applied to an unpainted sheet.

[0009] [Related Technical Literature]

[0010] [Patent Literature]

[0011] KR 2009-0095764 A Summary of the Invention

[0012] Technical Problem

[0013] Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a thermoplastic resin composition having excellent mechanical properties, weather resistance and processability; which can provide an aesthetic appearance due to its excellent low whitening characteristics despite its large thickness; and which is suitable for an unpainted sheet and an integral product having no seam between the substrate and the product.

[0014] Another object of the present invention is to provide a method for preparing the thermoplastic resin composition.

[0015] Still another object of the present invention is to provide a molded article including the thermoplastic resin composition.

[0016] The above and other objects can be achieved by the present invention described below.

[0017] Technical Solution

[0018] I) According to one aspect of the present invention, there is provided a thermoplastic resin composition comprising 100 parts by weight of a base resin, the base resin comprising 46 wt% to 81 wt% of a copolymer (A) and 19 wt% to 54 wt% of an aromatic vinyl compound-vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the copolymer (A) comprising an acrylic alkyl ester rubber having an average particle diameter of 50 nm to 150 nm, an aromatic vinyl compound and a vinyl cyanide compound; and 3 parts by weight or more of a thermoplastic polyester elastomer (C), wherein the thermoplastic resin composition has an acrylic alkyl ester coverage value (X) of 65 wt% or more calculated by Equation 1 below.

[0019] [Equation 1]

[0020] X = {(G - Y) / Y} × 100,

[0021] wherein G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

[0022] II) According to another aspect of the present invention, there is provided a thermoplastic resin composition comprising 100 parts by weight of a base resin, the base resin comprising 46 wt% to 81 wt% of an alkyl acrylate - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19 wt% to 54 wt% of an aromatic vinyl compound - vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the graft copolymer (A) comprising an alkyl acrylate rubber having an average particle size of 50 nm to 150 nm; and 3 parts by weight or more of a thermoplastic polyester elastomer (C), wherein the thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65 wt% or more calculated by the following Equation 1.

[0023] [Equation 1]

[0024] X = {(G - Y) / Y} × 100,

[0025] wherein G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

[0026] III) According to yet another aspect of the present invention, there is provided a thermoplastic resin composition comprising 100 parts by weight of a base resin, the base resin comprising 46 wt% to 81 wt% of an alkyl acrylate - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19 wt% to 54 wt% of an aromatic vinyl compound - vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the copolymer (A) comprising an alkyl acrylate rubber having an average particle size of 50 nm to 150 nm; and 3 parts by weight or more of a thermoplastic polyester elastomer (C).

[0027] IV) According to another aspect of the present invention, there is provided a thermoplastic resin composition comprising 100 parts by weight of a base resin, the base resin comprising 46% to 81% by weight of an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound - vinyl cyanide compound copolymer (B), the graft copolymer (A) comprising an acrylic alkyl ester rubber having an average particle size of 50 nm to 150 nm, the copolymer (B) comprising more than 10% and less than 26% by weight of a vinyl cyanide compound and having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol; and 3 parts by weight or more of a thermoplastic polyester elastomer (C), wherein the thermoplastic resin composition has an acrylic alkyl ester coverage value (X) of 65% or more calculated by the following Equation 1.

[0028] [Equation 1]

[0029] X = {(G - Y) / Y} × 100,

[0030] wherein G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the acrylic alkyl ester content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0031] V) According to I) to IV), based on the total weight of the graft copolymer (A), it may preferably comprise 20% to 60% by weight of an acrylic alkyl ester rubber and 40% to 80% by weight of an aromatic vinyl compound - vinyl cyanide compound copolymer surrounding the acrylic alkyl ester rubber.

[0032] VI) According to I) to V), the graft copolymer (A) may preferably have a graft degree of 60% or more calculated by the following Equation 2.

[0033] [Equation 2]

[0034] Graft degree (%) = [Weight of graft monomer (g) / Weight of rubber (g)] × 100

[0035] In Equation 2, the weight of the graft monomer (g) is obtained by subtracting the weight of the rubber (g) from the weight of the insoluble matter (gel) obtained by dissolving the graft copolymer in acetone and centrifuging, and the weight of the rubber (g) is the weight (g) of the rubber component theoretically added to the graft copolymer powder.

[0036] VII) According to I) to VI), the thermoplastic polyester elastomer (C) may preferably have a melt flow rate of 0.5 g / 10 min to 10 g / 10 min measured at a temperature of 230 °C under a load of 2.16 kg according to ASTM D1238.

[0037] VIII) According to I) to VII), the thermoplastic polyester elastomer (C) may preferably be an elastomer comprising an aromatic dicarboxylic acid or its ester derivative, an aliphatic diol, and a polyalkylene oxide.

[0038] IX) According to I) to VIII), the aromatic dicarboxylic acid may preferably include one or more selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0039] X) According to I) to IX), the aliphatic diol may preferably include one or more selected from ethylene glycol, propylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol.

[0040] XI) According to I) to X), the polyalkylene oxide may preferably include one or more selected from polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexamethylene glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide addition polymers of polypropylene glycol, and copolymers of ethylene oxide and tetrahydrofuran.

[0041] XII) According to I) to XI), after cupping the central portion of a 0.3 mm thick sheet to a depth of 8 mm at a speed of 10 mm / min using a 20 mm diameter ball and an electric Erichsen cupping tester, when measuring the values before and after cupping using a color difference meter and calculating the color difference (ΔE) by the following Equation 3, the thermoplastic resin composition may preferably have a color difference (ΔE) of 2.0 or less.

[0042] [Equation 3]

[0043]

[0044] In Equation 3, L', a', and b' respectively represent the L, a, and b values measured using the CIE LAB color coordinate system after cupping, and L0, a0, and b0 respectively represent the L, a, and b values measured using the CIE LAB color coordinate system before cupping.

[0045] XIII) According to I) to XII), the thermoplastic resin composition may preferably have a Rockwell hardness of 44 or more measured on the R-scale according to ASTM D785.

[0046] XIV) According to yet another aspect of the present invention, there is provided a method for preparing a thermoplastic resin composition, the method comprising kneading and extruding 100 parts by weight of a base resin and 3 parts by weight or more of a thermoplastic polyester elastomer (C) at 200 °C to 300 °C and 100 rpm to 500 rpm, the base resin comprising 46% to 81% by weight of an acrylic alkyl ester-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (B), the graft copolymer (A) comprising an acrylic alkyl ester rubber having an average particle size of 50 nm to 150 nm, the copolymer (B) comprising 10% or more and less than 26% by weight of a vinyl cyanide compound and having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, wherein the thermoplastic resin composition has an acrylic alkyl ester coverage value (X) of 65% by weight or more calculated by the following Equation 1.

[0047] [Equation 1]

[0048] X = {(G - Y) / Y} × 100,

[0049] wherein G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the acrylic alkyl ester content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0050] XV) According to still another aspect of the present invention, there is provided a molded article comprising the thermoplastic resin composition according to any one of I) to XIII).

[0051] XVI) According to XV), the molded article may be an unpainted sheet.

[0052] Advantageous Effects

[0053] According to the present invention, the present invention has the following effects: providing a thermoplastic resin composition having excellent mechanical properties, weather resistance, and processability; being able to provide a beautiful appearance due to its excellent low whitening property despite its large thickness; and being applicable to unpainted sheets and integral products having no seams between a substrate and a product, a method for preparing the thermoplastic resin composition, and a molded article comprising the thermoplastic resin composition. Specifically, according to the present invention, a thick sheet has excellent low whitening properties, thereby improving the covering power of a substrate and providing a masking effect for defective appearances such as foreign substances and unevenness of an underlying substrate, thereby improving the appearance quality and emotional quality.

[0054] In addition, since the thermoplastic resin composition of the present invention can be easily applied to unpainted molded articles, especially unpainted sheets, the thermoplastic resin composition has the advantages of reducing production costs and being eco-friendly. Description of the Drawings

[0055] Figure 1 Including images of the cupped sheets obtained after cupping the sheets manufactured in Example 1 and Comparative Example 1 using an electric Erichsen cupping tester. Detailed Description of the Invention

[0056] Hereinafter, the thermoplastic resin composition of the present invention, a method for preparing the same, and a molded article including the same will be described in detail.

[0057] The present inventors confirmed that when a base resin and a thermoplastic polyester elastomer in a predetermined content are included and the acrylic alkyl ester coverage value of the thermoplastic resin composition is adjusted within a predetermined range, the base resin includes an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer containing rubber having a predetermined average particle size and an aromatic vinyl compound - vinyl cyanide compound copolymer containing a predetermined content of vinyl cyanide compound and having a weight average molecular weight within a given range. By reducing the occurrence of whitening when bending a thick sheet, a beautiful appearance is achieved, and the balance among mechanical properties, weather resistance, and processability is improved. Based on these findings, the present inventors conducted further research to complete the present invention.

[0058] The thermoplastic resin composition according to the present invention will be described in detail below.

[0059] The thermoplastic resin composition of the present invention contains 100 parts by weight of a base resin, the base resin containing 46 wt% to 81 wt% of a copolymer (A) and 19 wt% to 54 wt% of an aromatic vinyl compound - vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the copolymer (A) containing an acrylic alkyl ester rubber having an average particle size of 50 nm to 150 nm, an aromatic vinyl compound, and a vinyl cyanide compound; and 3 parts by weight or more of a thermoplastic polyester elastomer (C). The thermoplastic resin composition has an acrylic alkyl ester coverage value (X) of 65 wt% or more calculated by Equation 1 below. In this case, the thermoplastic resin composition can have excellent mechanical properties, weather resistance, and processability. Although its thickness is large, due to its excellent low whitening property, it can provide a beautiful appearance and can be applied to unpainted sheets and one-piece products without seams between the substrate and the product.

[0060] [Equation 1]

[0061] X = {(G - Y) / Y} × 100

[0062] In Equation 1, G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

[0063] For example, the copolymer (A) may be an alkyl acrylate - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm. In this case, mechanical properties, weather resistance, and processability may be excellent, and the occurrence of whitening during bending processing can be reduced.

[0064] Furthermore, the thermoplastic resin composition of the present invention contains 100 parts by weight of a base resin, the base resin containing 46 wt% to 81 wt% of an alkyl acrylate - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19 wt% to 54 wt% of an aromatic vinyl compound - vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the copolymer (A) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm; and 3 parts by weight or more of a thermoplastic polyester elastomer (C). The thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65 wt% or more calculated by Equation 1 below. In this case, the thermoplastic resin composition can have excellent mechanical properties, weather resistance, and processability, and can provide an aesthetic appearance due to its excellent low whitening property despite its large thickness, and can be applied to unpainted sheets and integrated products having no seams between the substrate and the product.

[0065] [Equation 1]

[0066] X = {(G - Y) / Y} × 100

[0067] In Equation 1, G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

[0068] In addition, the thermoplastic resin composition of the present invention contains 100 parts by weight of a base resin, the base resin containing 46% to 81% by weight of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (B) having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, the graft copolymer (A) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm; and 3 parts by weight or more of a thermoplastic polyester elastomer (C). In this case, the thermoplastic resin composition can have excellent mechanical properties, weather resistance, and processability, and although its thickness is large, due to its excellent low whitening property, it can provide a beautiful appearance and can be applied to unpainted sheets and integral products having no seams between the base material and the product.

[0069] In addition, the thermoplastic resin composition of the present invention contains 100 parts by weight of a base resin, the base resin containing 46% to 81% by weight of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (B), the graft copolymer (A) containing an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm, the copolymer (B) containing 10% or more and less than 26% by weight of a vinyl cyanide compound and having a weight average molecular weight of 65,000 g / mol to 110,000 g / mol; and 3 parts by weight or more of a thermoplastic polyester elastomer (C). The thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65% by weight or more calculated by the following Equation 1. In this case, the thermoplastic resin composition can have excellent mechanical properties, weather resistance, and processability, and although its thickness is large, due to its excellent low whitening property, it can provide a beautiful appearance and can be applied to unpainted sheets and integral products having no seams between the base material and the product.

[0070] [Equation 1]

[0071] X = {(G - Y) / Y} × 100

[0072] In Equation 1, G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0073] Hereinafter, each component of the thermoplastic resin composition of the present invention will be described in detail.

[0074] (A) Acrylic alkyl ester - aromatic vinyl - vinyl cyanide compound graft copolymer containing acrylic alkyl ester rubber with an average particle size of 50 nm to 150 nm

[0075] For example, based on the total weight of the base resin, the graft copolymer (A) may be included in an amount of 46% to 81% by weight, preferably 50% to 77% by weight, more preferably 57% to 74% by weight, still more preferably 65% to 73% by weight. Within this range, mechanical properties and transparency can be excellent, and even at large thicknesses, low whitening characteristics can be excellent.

[0076] The graft copolymer (A) may preferably be composed of an alkyl acrylate rubber (core) and an aromatic vinyl compound-vinyl cyanide compound copolymer (shell) surrounding the core.

[0077] For example, based on its total weight, the graft copolymer (A) may contain 20% to 60% by weight of an alkyl acrylate rubber and 40% to 80% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer surrounding the alkyl acrylate rubber, preferably 30% to 50% by weight of an alkyl acrylate rubber and 50% to 70% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer surrounding the alkyl acrylate rubber, more preferably 40% to 50% by weight of an alkyl acrylate rubber and 50% to 60% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer surrounding the alkyl acrylate rubber. Within this range, mechanical properties, weather resistance, and processability can be excellent, and the occurrence of whitening during bending processing can be reduced.

[0078] For example, the alkyl acrylate rubber may have an average particle diameter of 50 nm to 150 nm, more preferably 60 nm to 140 nm, still more preferably 70 nm to 140 nm, still more preferably 80 nm to 130 nm, still more preferably 90 nm to 130 nm. Within this range, the finally prepared thermoplastic resin composition can have excellent permeability and glossiness.

[0079] In the present disclosure, the average particle diameter is measured by dynamic light scattering. Specifically, the average particle diameter is measured as an intensity value using a Nicomp 380 particle size analyzer (manufacturer: PSS) in the Gaussian mode. As a specific measurement example, a sample is prepared by diluting 0.1 g of latex (total solid content: 35% to 50% by weight) 1,000 to 5,000 times with distilled water. Then, in the measurement mode of dynamic light scattering / intensity 300 kHz / intensity-weighted Gaussian analysis, the average particle diameter of the sample is measured using a flow cell with automatic dilution. At this time, the set values are as follows: temperature: 23 °C, measurement wavelength: 632.8 nm, channel width: 10 microseconds.

[0080] For example, an alkyl acrylate rubber can be prepared by performing emulsion polymerization of an alkyl acrylate, preferably by mixing an alkyl acrylate, an emulsifier, an initiator, a grafting agent, a crosslinking agent, an electrolyte, and a solvent and performing emulsion polymerization of the mixture. In this case, due to excellent grafting efficiency, the mechanical properties can be excellent.

[0081] For example, the alkyl acrylate rubber may further contain an aromatic vinyl compound. In this case, the chemical resistance and impact resistance can be further improved.

[0082] For example, based on 100% by weight of the alkyl acrylate rubber in total, the alkyl acrylate rubber may contain 0.1% to 25% by weight, preferably 2% to 23% by weight, more preferably 5% to 20% by weight of the aromatic vinyl compound. Within this range, the impact resistance, glossiness, transparency, and weather resistance can be excellent without deterioration of physical properties, and the change over time can be reduced.

[0083] For example, the alkyl acrylate rubber may include seeds, preferably rubber seeds.

[0084] For example, based on 100% by weight of the graft copolymer (A), seeds can be prepared by polymerizing 1% to 20% by weight, preferably 2% to 15% by weight, more preferably 3% to 10% by weight of one or more monomers selected from aromatic vinyl compounds, vinyl cyanide compounds, and alkyl acrylates. Within this range, the impact strength, weather resistance, and balance of physical properties can be excellent.

[0085] For example, the aromatic vinyl compound-vinyl cyanide compound copolymer (shell) may have a weight-average molecular weight of 40,000 g / mol to 120,000 g / mol, preferably 50,000 g / mol to 110,000 g / mol, more preferably 60,000 g / mol to 110,000 g / mol. Within this range, the processability can be excellent without deteriorating the impact strength, and the occurrence of whitening can be reduced during bending processing.

[0086] In the present disclosure, unless otherwise defined, the weight-average molecular weight can be measured by gel permeation chromatography (GPC, Waters Breeze). As a specific example, the weight-average molecular weight can be measured by gel permeation chromatography (GPC, Waters Breeze) using tetrahydrofuran (THF) as the eluent. In this case, the weight-average molecular weight is obtained as a relative value with respect to a polystyrene (PS) standard sample. As a specific measurement example, the weight-average molecular weight can be measured under the following conditions: solvent: THF, column temperature: 40 °C, flow rate: 0.3 ml / min, sample concentration: 20 mg / ml, injection volume: 5 μl, column type: 1 × PLgel 10 μm MiniMix-B (250 × 4.6 mm) + 1 × PLgel 10 μm MiniMix-B (250 × 4.6 mm) + 1 × PLgel 10 μm MiniMix-B Guard (50 × 4.6 mm), equipment name: Agilent 1200 series system, refractive index detector: Agilent G1362 RID, RI temperature: 35 °C, data processing: Agilent ChemStation S / W, test method (Mn, Mw and PDI): OECD TG 118.

[0087] For example, based on its total weight, the aromatic vinyl compound-vinyl cyanide compound copolymer (shell) can contain 55% to 85% by weight of an aromatic vinyl compound and 15% to 45% by weight of a vinyl cyanide compound, preferably 60% to 80% by weight of an aromatic vinyl compound and 20% to 40% by weight of a vinyl cyanide compound, more preferably 65% to 75% by weight of an aromatic vinyl compound and 25% to 35% by weight of a vinyl cyanide compound. Within this range, the impact resistance and weather resistance can be excellent.

[0088] The aromatic vinyl compound-vinyl cyanide compound copolymer (shell) can preferably contain an alkyl acrylate. In this case, the impact resistance, weather resistance and processability can be excellent, and the occurrence of whitening during bending processing can be reduced.

[0089] For example, based on its total weight, the aromatic vinyl compound-vinyl cyanide compound copolymer (shell) may contain 55% to 85% by weight of an aromatic vinyl compound, 10% to 35% by weight of a vinyl cyanide compound, and 1% to 25% by weight of an alkyl acrylate, preferably 60% to 80% by weight of an aromatic vinyl compound, 15% to 30% by weight of a vinyl cyanide compound, and 3% to 20% by weight of an alkyl acrylate, more preferably 65% to 72% by weight of an aromatic vinyl compound, 20% to 25% by weight of a vinyl cyanide compound, and 5% to 15% by weight of an alkyl acrylate. Within this range, the impact resistance and weather resistance can be further improved.

[0090] For example, the graft copolymer (A) can be prepared by emulsion polymerization. In this case, the glossiness and surface hardness can be excellent.

[0091] The emulsion polymerization can be carried out using the emulsion polymerization methods commonly used in the technical field to which the present invention pertains, without particular limitation. For example, an emulsion graft polymerization method can be used.

[0092] For example, the graft copolymer (A) can have a graft degree of more than 60%, preferably 60% to 150%, more preferably 65% to 140%, still more preferably 65% to 130%, still more preferably 65% to 100%, still more preferably 65% to 80% calculated by the following Equation 2. Within this range, the impact resistance and processability can be excellent, and the occurrence of whitening during bending processing can be reduced.

[0093] [Equation 2]

[0094] Graft degree (%) = [Weight of graft monomer (g) / Weight of rubber (g)] × 100

[0095] In Equation 2, the weight of the graft monomer (g) is obtained by subtracting the weight of the rubber (g) from the weight of the insoluble matter (gel) obtained by dissolving the graft copolymer in acetone and centrifuging. The weight of the rubber (g) is the weight (g) of the rubber component theoretically added to the graft copolymer powder.

[0096] When measuring the weight of the insoluble matter (gel), 0.5 g of the powdered graft copolymer is added to 50 ml of acetone, and then stirred at room temperature for 12 hours. Then, centrifugation is carried out to separate the insoluble matter that is not dissolved in acetone, and then dried for 12 hours. Then, the weight of the insoluble matter (gel) is measured. The weight of the rubber (g) is the weight (g) of the rubber component theoretically added to 0.5 g of the powdered graft copolymer.

[0097] As a specific measurement example, when measuring the weight (g) of the insoluble substance (gel), 0.5 g of the powdery graft copolymer was added to 50 ml of acetone, and then stirred using an orbital shaker (equipment name: Lab companion SKC-6075) at 210 rpm and room temperature for 12 hours. Then, centrifugation was performed using a centrifuge (Supra R30, Hanil Science Co.) at 0 °C and 18,000 rpm for 3 hours to separate the insoluble substance that did not dissolve in acetone, and then dried by forced circulation in a forced convection oven (equipment name: Lab companion OF-12GW) set at 85 °C for 12 hours. Then, the weight of the insoluble substance (gel) was measured.

[0098] In the present disclosure, room temperature can be any point within the range of 20 ± 5 °C.

[0099] For example, the alkyl acrylate of the present invention can be an alkyl acrylate containing an alkyl group having 1 to 15 carbon atoms. Preferably, the alkyl acrylate can include one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, heptyl acrylate, n-pentyl acrylate, and lauryl acrylate, more preferably an alkyl acrylate having an alkyl group of 1 to 4 or 8 carbon atoms, still more preferably butyl acrylate, 2-ethylhexyl acrylate, or a mixture thereof, and still more preferably butyl acrylate.

[0100] For example, the aromatic vinyl compound of the present invention can include one or more selected from styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, ethylstyrene, isobutylstyrene, tert-butylstyrene, o-bromostyrene, p-bromostyrene, m-bromostyrene, o-chlorostyrene, p-chlorostyrene, m-chlorostyrene, vinyltoluene, vinylxylene, fluorostyrene, and vinylnaphthalene, preferably one or more selected from styrene and α-methylstyrene, and more preferably styrene. In this case, due to appropriate fluidity, processing properties and mechanical properties such as impact resistance can be excellent.

[0101] The vinyl cyanide of the present invention can include one or more selected from acrylonitrile, methacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile, and preferably acrylonitrile.

[0102] In the present disclosure, a polymer containing a certain compound (monomer) means a polymer prepared by polymerizing the compound (monomer), and the units in the polymer are derived from the compound.

[0103] (B) Aromatic vinyl compound - vinyl cyanide compound copolymer

[0104] For example, based on the total weight of the base resin, the copolymer (B) can be included in an amount of 19% by weight to 54% by weight, preferably 23% by weight to 50% by weight, more preferably 26% by weight to 43% by weight, and even more preferably 27% by weight to 35% by weight. Within this range, the processability and low whitening characteristics can be excellent.

[0105] For example, the copolymer (B) can be a copolymer containing an aromatic vinyl compound and a vinyl cyanide compound. In this case, the processability and low whitening characteristics can be excellent.

[0106] For example, based on its total weight, the copolymer (B) can contain more than 10% by weight and less than 26% by weight, preferably 13% by weight to 23% by weight or 15% by weight to 25.5% by weight, more preferably 15% by weight to 25.5% by weight, even more preferably 17% by weight to 25.5% by weight, even more preferably 19% by weight to 25.5% by weight, and even more preferably 20% by weight to 25.5% by weight of the vinyl cyanide compound. Within this range, the occurrence of whitening during bending processing can be reduced even in thick sheets, and the processability can be excellent.

[0107] In the present disclosure, unless otherwise specified, the sheet refers to a sheet, film, or foil.

[0108] For example, the weight-average molecular weight of the copolymer (B) can be 65,000 g / mol to 110,000 g / mol, preferably 70,000 g / mol to 100,000 g / mol, more preferably 70,000 g / mol to 90,000 g / mol, and even more preferably 75,000 g / mol to 85,000 g / mol. Within this range, the occurrence of whitening during bending processing can be reduced even in thick sheets, and the processability can be excellent.

[0109] The types of the aromatic vinyl compound and the vinyl cyanide compound constituting the copolymer (B) can be the same as those of the aromatic vinyl compound and the vinyl cyanide compound contained in the graft copolymer (A) of the present invention.

[0110] The copolymer (B) can preferably be a styrene-acrylonitrile copolymer (SAN resin), an α-methylstyrene-acrylonitrile copolymer (heat-resistant SAN resin), or a mixture thereof, and more preferably a styrene-acrylonitrile copolymer (SAN resin). In this case, the processability, gloss, and surface hardness can be excellent.

[0111] For example, the copolymer (B) can be prepared by suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization, preferably bulk polymerization. In this case, the mechanical properties can be excellent.

[0112] Suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization can be carried out using the suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization methods generally practiced in the technical field to which the present invention pertains, without particular limitation.

[0113] (C) Thermoplastic polyester elastomer

[0114] For example, based on 100 parts by weight of the base resin, the thermoplastic polyester elastomer (C) can be included in an amount of 3 parts by weight or more, preferably 5 parts by weight or more, more preferably 7 parts by weight or more, still more preferably 9 parts by weight or more, or 35 parts by weight or less, preferably 27 parts by weight or less, still more preferably 9 to 35 parts by weight, still more preferably 9 to 27 parts by weight. Within this range, mechanical properties and processability can be excellent, and the occurrence of whitening during bending processing can be reduced even at a large thickness, thus enabling an aesthetically pleasing appearance. In addition, the composition of the present invention can be applied to unpainted sheets and integrated products without seams between the substrate and the product.

[0115] For example, the thermoplastic polyester elastomer (C) can be an elastomer containing an aromatic dicarboxylic acid or its ester derivative, an aliphatic diol, and a polyalkylene oxide. In this case, flexibility, mechanical strength, and heat resistance can be increased, and the physical balance can be excellent.

[0116] For example, the crystalline hard segment can be formed from an aromatic dicarboxylic acid or its ester derivative and an aliphatic diol, the soft segment can be formed from a polyalkylene oxide, and the crystalline hard segment and the soft segment can be randomly arranged.

[0117] For example, the aromatic dicarboxylic acid can include one or more selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid, preferably terephthalic acid, isophthalic acid, or a mixture thereof.

[0118] For example, the ester derivative of the aromatic dicarboxylic acid can include one or more selected from dimethyl terephthalate, dimethyl isophthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl 1,5-naphthalenedicarboxylate, and dimethyl 1,4-cyclohexanedicarboxylate, preferably dimethyl terephthalate, dimethyl isophthalate, or a mixture thereof.

[0119] Based on the total weight of the thermoplastic polyester elastomer, the aromatic dicarboxylic acid or its ester derivative can be included in an amount of 25% to 70% by weight, preferably 30% to 65% by weight, more preferably 35% to 60% by weight. Within this range, the reaction can be easily carried out.

[0120] For example, the aliphatic diol can have a number average molecular weight of 300 g / mol or less, preferably 60 g / mol to 300 g / mol.

[0121] In the present disclosure, unless otherwise defined, the number-average molecular weight can be measured by gel permeation chromatography (GPC, Waters Breeze). As a specific example, the number-average molecular weight can be measured by gel permeation chromatography (GPC, Waters Breeze) using tetrahydrofuran (THF) as the eluent. In this case, the number-average molecular weight is obtained as a relative value of a polystyrene (PS) standard sample. As a specific measurement example, the number-average molecular weight can be measured under the following conditions: solvent: THF, column temperature: 40 °C, flow rate: 0.3 ml / min, sample concentration: 20 mg / ml, injection volume: 5 μl, column type: 1×PLgel 10 μm MiniMix-B (250×4.6 mm) + 1×PLgel 10 μm MiniMix-B (250×4.6 mm) + 1×PLgel 10 μm MiniMix-B Guard (50×4.6 mm), equipment name: Agilent 1200 series system, refractive index detector: Agilent G1362 RID, RI temperature: 35 °C, data processing: Agilent ChemStation S / W, test method (Mn, Mw and PDI): OECD TG 118.

[0122] The aliphatic diol may preferably include one or more selected from ethylene glycol, propylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol, more preferably 1,4-butanediol.

[0123] For example, based on the total weight of the thermoplastic polyester elastomer, the aliphatic diol may be included in an amount of 15% to 45% by weight, preferably 20% to 40% by weight, more preferably 25% to 40% by weight. Within this range, the reaction can proceed smoothly, and the physical property balance between flexibility and mechanical strength can be excellent.

[0124] For example, the polyalkylene oxide may be an aliphatic polyester and may include one or more selected from the following as the soft segment: polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexamethylene glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide adduct polymer of polypropylene glycol, and a copolymer of ethylene oxide and tetrahydrofuran, preferably polybutylene glycol.

[0125] For example, based on the total weight of the thermoplastic polyester elastomer, the polyalkylene oxide may be included in an amount of 5% to 50% by weight, preferably 10% to 45% by weight, more preferably 15% to 40% by weight. Within this range, the flexibility, mechanical strength, heat resistance, and physical property balance can be excellent.

[0126] For example, the polyalkylene oxide may have a number average molecular weight of 600 g / mol to 3,000 g / mol, preferably 1,000 g / mol to 2,000 g / mol. Within this range, the polymerization reaction can proceed stably, and a thermoplastic polyester elastomer having an excellent balance of physical properties can be obtained.

[0127] The polyalkylene oxide may preferably be a polypropylene glycol having terminals capped with ethylene oxide. In this case, the polymerization reactivity can be excellent.

[0128] The thermoplastic polyester elastomer (C) may preferably contain a branching agent. In this case, the melt viscosity and melt strength of the elastomer can be increased.

[0129] For example, the branching agent may include one or more selected from glycerin, pentaerythritol, trimellitic anhydride, trimellitic acid, trimethylolpropane, and neopentyl glycol, preferably trimellitic anhydride.

[0130] For example, based on 100% by weight of the thermoplastic polyester elastomer, the branching agent may be contained in an amount of 0.05% by weight to 0.1% by weight, preferably 0.05% by weight to 0.09% by weight, more preferably 0.06% by weight to 0.09% by weight. Within this range, the melt strength can be increased.

[0131] For example, the thermoplastic polyester elastomer (C) can be prepared by melt polymerization of an aromatic dicarboxylic acid or its ester derivative, an aliphatic diol, and a polyalkylene oxide. In this case, the balance of physical properties among flexibility, mechanical strength, and heat resistance can be excellent, and the formability can be further improved.

[0132] The thermoplastic polyester elastomer (C) may preferably be prepared by additional solid-state polymerization of a resin prepared by melt polymerization. In this case, the balance of physical properties among flexibility, mechanical strength, and heat resistance can be excellent, and the formability can be further improved.

[0133] Preferably, when preparing the thermoplastic polyester elastomer, the aromatic dicarboxylic acid, aliphatic diol, and polyalkylene oxide are subjected to transesterification at 140 °C to 215 °C for 110 minutes to 130 minutes under a tetrabutyl titanate (TBT) catalyst to obtain a bis(4-hydroxy)butyl terephthalate (BHBT) oligomer, the TBT catalyst is added again, and then melt polymerization is carried out at 215 °C to 245 °C while gradually reducing the pressure from 760 Torr to 0.3 Torr for 110 minutes to 130 minutes.

[0134] The melt polymerization reaction can be carried out until the melt flow rate measured at 230 °C under a load of 2.16 kg according to ASTM D1238 reaches 20 g / 10 min. After the reaction is completed, the product can be discharged from the reactor by nitrogen pressure and can be obtained in the form of pellets by strand pelletizing.

[0135] Then, the pellets can be subjected to solid-state polymerization at 140 °C to 200 °C for 10 hours to 24 hours in an inert atmosphere such as a nitrogen atmosphere in a solid-state polymerization reactor or a rotatable vacuum dryer.

[0136] High viscosity can be achieved by solid-state polymerization until the melt flow rate measured at 230 °C under a load of 2.16 kg according to ASTM D1238 is below 10 g / 10 min, preferably 0.5 g / 10 min to 10 g / 10 min, more preferably 1 g / 10 min to 10 g / 10 min, and still more preferably 3 g / 10 min to 8 g / 10 min.

[0137] The degree of vacuum applied during solid-state polymerization can be selected within the degree of vacuum commonly used in the field to which the present invention pertains, without particular limitation.

[0138] The solid-state polymerization reactor can be a container-type vacuum dryer connected to a rotatable high-vacuum pump, and the inert atmosphere can be a nitrogen atmosphere.

[0139] In the present disclosure, the content of the monomer in the polymer can mean the weight (% by weight) of the monomer added during polymer preparation or the weight (% by weight) of the unit derived from the monomer (based on the monomer).

[0140] The thermoplastic polyester elastomer (C) can have a melt flow rate of 0.5 g / 10 min to 10 g / 10 min, preferably 1 g / 10 min to 10 g / 10 min, more preferably 3 g / 10 min to 8 g / 10 min, measured at 230 °C under a load of 2.16 kg according to ASTM D1238. Within this range, the forming properties can be excellent.

[0141] For example, the thermoplastic polyester elastomer (C) can have a Shore hardness of 30D to 50D, preferably 35D to 47D, more preferably 35D to 40D. Within this range, the flexibility and mechanical strength of the composition can be excellent.

[0142] In the present disclosure, unless otherwise specified, the Shore hardness can be measured according to the method specified in ISO 868 (Type D).

[0143] In the present disclosure, the elastomer may also be referred to as an elastic polymer or an elastic rubber, as in the technical field to which the present invention pertains, and commercially available products may be used as long as the products comply with the definition of the present invention.

[0144] Thermoplastic resin composition

[0145] The thermoplastic resin composition may have an acrylic alkyl ester coverage rate (X) value calculated by the following Equation 1 of 65% by weight or more, more preferably 70% by weight or more, still more preferably 70% to 150% by weight, still more preferably 70% to 140% by weight, still more preferably 75% to 140% by weight, still more preferably 80% to 130% by weight. Within this range, the mechanical properties, weather resistance, and processability may be excellent, and even the low whitening property may be excellent even at a large thickness, and the composition may be applied to unpainted molded articles.

[0146] [Equation 1]

[0147] X = {(G - Y) / Y} × 100

[0148] In Equation 1, G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the acrylic alkyl ester content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0149] In Equation 1, the content of acrylic alkyl ester in the gel of the thermoplastic resin composition represents the content of acrylic alkyl ester in the insoluble matter collected during the process of obtaining the above gel content (based on 100% by weight of all the introduced thermoplastic resin composition). Here, the gel content represents the content of insoluble matter based on 100% by weight of all the thermoplastic resin composition. The insoluble matter is derived from a polymer or copolymer combined with rubber. In the present invention, the polymer or copolymer combined with rubber may be an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A).

[0150] The content of acrylic alkyl ester is quantitatively measured by nuclear magnetic resonance (NMR) analysis or Fourier transform infrared spectroscopy (FT-IR) analysis.

[0151] In the present disclosure, unless otherwise specified, NMR analysis means 1 1H NMR analysis.

[0152] In the present disclosure, NMR analysis may be carried out using methods commonly practiced in the art, and specific measurement examples are as follows.

[0153] - Equipment Name: Bruker 600MHz NMR (AVANCE III HD) CPP BB (1H 19F Tunable and Broadband with z-gradient) Prodigy Probe

[0154] - Measurement Conditions: 1H NMR (zg30): ns = 32, d1 = 5s, TCE-d2, at room temperature.

[0155] In the present disclosure, FT-IR analysis can be performed using methods commonly implemented in the art, and specific measurement examples are as follows.

[0156] - Equipment Name: Agilent Cary 660

[0157] - Measurement Conditions: ATR mode

[0158] When measuring the gel content, 1 g of the thermoplastic resin composition is added to 30 ml of acetone, and then stirred at room temperature for 12 hours. Then, centrifugation is performed to separate the insoluble matter that is not dissolved in acetone, and then dried for 12 hours. Then, the weight of the insoluble matter is measured, and the gel content is calculated by Equation 4 below. As a specific measurement example, when measuring the gel content, 1 g of the thermoplastic resin composition is added to 30 ml of acetone, and then stirred at 210 rpm and room temperature for 12 hours using an orbital shaker (Equipment Name: Lab companion SKC-6075). Then, centrifugation is performed at 0 °C and 18,000 rpm for 3 hours using a centrifuge (Supra R30, Hanil Science Co.) to separate the insoluble matter that is not dissolved in acetone, and then dried for 12 hours by forced circulation in a forced convection oven (Equipment Name: Lab companion OF-12GW) set at 85 °C. Then, the weight of the insoluble matter is measured, and the gel content is calculated by Equation 4 below.

[0159] [Equation 4]

[0160] Gel content (wt%) = [Weight of insoluble matter (gel) (g) / Weight of sample (g)] × 100

[0161] In the present disclosure, the acrylic alkyl ester coverage value is a parameter for measuring the degree of dispersion of an aromatic vinyl compound-vinyl cyanide compound polymer grafted onto an acrylic alkyl ester rubber in a thermoplastic resin composition. When the acrylic alkyl ester coverage value is high, the aromatic vinyl compound-vinyl cyanide compound polymer is uniformly grafted onto the acrylic alkyl ester rubber to uniformly cover the acrylic alkyl ester rubber, thereby improving gloss and achieving excellent tensile strength, coloring property, and non-whitening property. In addition, as the acrylic alkyl ester coverage value increases, the distance between rubber particles decreases, thereby reducing voids caused by cracks occurring within the thermoplastic resin composition and suppressing whitening during bending.

[0162] Here, the acrylic alkyl ester coverage value indicates the degree of dispersion of an aromatic vinyl compound-vinyl cyanide compound polymer grafted onto the acrylic alkyl ester in a thermoplastic resin composition, and the grafting degree indicates the degree to which the aromatic vinyl compound-vinyl cyanide compound polymer is grafted onto the acrylic alkyl ester in the acrylic alkyl ester-aromatic vinyl compound-vinyl cyanide graft copolymer.

[0163] Furthermore, the acrylic alkyl ester coverage value is obtained by quantitatively calculating the content of the acrylic alkyl ester present in the thermoplastic resin composition through nuclear magnetic resonance (NMR) analysis or Fourier transform infrared spectroscopy (FT-IR) analysis, and the grafting degree is obtained based on the content of the rubber component added during polymerization.

[0164] After the central portion of a 0.3 mm thick sheet is cupped to a depth of 8 mm at a speed of 10 mm / min using a 20 mm diameter ball and an electric Erichsen cupping tester, when the values before and after cupping are measured using a color difference meter and the color difference (ΔE) is calculated by the following Equation 3, the thermoplastic resin composition may preferably have a color difference (ΔE) of 2.0 or less, more preferably 1.6 or less, still more preferably 1.3 or less, still more preferably 1.0 or less, still more preferably 0.8 or less, still more preferably 0.6 or less. Within this range, the whitening phenomenon occurring during bending or folding treatment can be reduced, and thus the low-whitening property can be excellent. Therefore, the appearance quality and emotional quality can be improved, and the composition can be applied to unpainted molded articles.

[0165] [Equation 3]

[0166]

[0167] In Equation 3, L', a', and b' respectively represent the L, a, and b values measured using the CIE LAB color coordinate system after cupping, and L0, a0, and b0 respectively represent the L, a, and b values measured using the CIE LAB color coordinate system before cupping.

[0168] The thermoplastic resin composition may have a Rockwell hardness of preferably 44 or more, more preferably 49 or more, still more preferably 54 or more, still more preferably 59 or more, still more preferably 64 or more, measured on the R-scale according to ASTM D785. Within this range, due to excellent surface hardness, the appearance quality and emotional quality can be improved.

[0169] The thermoplastic resin composition may have a tensile strength of preferably 180 kgf / cm 2 or more, preferably 200 kgf / cm 2 or more, more preferably 220 kgf / cm 2 or more, still more preferably 220 kgf / cm 2 to 420 kgf / cm 2 measured according to ASTM D638 using an injection specimen with a thickness of 3 mm at a crosshead speed of 50 mm / min. Within this range, the physical property balance and processability can be excellent.

[0170] The thermoplastic resin composition may have an elongation at break of preferably 55% or more, more preferably 70% or more, still more preferably 90% or more, still more preferably 110% or more, still more preferably 110% to 200%, measured according to ASTM D638 using an injection specimen with a thickness of 3 mm at a crosshead speed of 50 mm / min. Within this range, the physical property balance and processability can be excellent.

[0171] The thermoplastic resin composition may have a flexural strength of 270 kgf / cm 2 or more, more preferably 300 kgf / cm 2 or more, still more preferably 350 kgf / cm 2 or more, still more preferably 400 kgf / cm 2 or more, still more preferably 400 kgf / cm 2 to 600 kgf / cm 2 measured according to ASTM D790 using an injection specimen with a thickness of 3 mm at a span of 50 mm and a test speed of 10 mm / min. Within this range, the physical property balance and processability can be excellent.

[0172] When a sheet made of the thermoplastic resin composition with a thickness of 0.3 mm is extruded to a length of 1 m or more using a T-die extruder at a molding temperature of 220°C, a screw speed of 100 rpm, a roll temperature of 85°C, and a roll speed of 1.5 m / min, no bursting occurs. In this case, the physical property balance and processability can be excellent, and the appearance quality and emotional quality can be improved.

[0173] When a sheet made of a thermoplastic resin composition with a thickness of 0.3 mm is extruded to a length of more than 1 m using a T-die extruder at a molding temperature of 220 °C, a screw speed of 100 rpm, a roll temperature of 85 °C, and a roll speed of 1.5 m / min, the width and thickness of the sheet are measured at more than 10 positions, and the sheet has a deviation of ±10% or less. Within this range, the balance of physical properties and processability can be excellent, and the appearance quality and emotional quality can be improved.

[0174] In the present invention, Techine 20T (screw diameter: 20 mm, L / D = 25, Collins Co.) can be used as the T-die extruder.

[0175] Based on 100 parts by weight of the base resin, the thermoplastic resin composition may further contain 0.01 to 5 parts by weight, 0.05 to 3 parts by weight, 0.1 to 2 parts by weight, or 0.5 to 1 part by weight of one or more selected from heat stabilizers, light stabilizers, dyes, pigments, colorants, lubricants, mold release agents, antistatic agents, antibacterial agents, processing aids, metal deactivators, flame retardants, smoke suppressants, anti-drip agents, anti-friction agents, and anti-wear agents. Within this range, the desired properties can be effectively implemented without degrading the inherent properties of the thermoplastic resin composition of the present invention.

[0176] The heat stabilizer may preferably include a primary heat stabilizer and a secondary heat stabilizer.

[0177] For example, the primary heat stabilizer may be a phenol-based heat stabilizer. Preferably, the primary heat stabilizer may include one or more selected from 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-amylphenyl)ethyl]-4,6-di-tert-amylphenyl acrylate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-thiobis(ethylidene)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, tris(4-tert-butyl-2,6-dimethyl-3-hydroxybenzyl)isocyanurate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol) terephthalate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 2,2-bis[4-(2-3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)ethoxyphenyl]propane, and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and more preferably octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (IR1076).

[0178] For example, the secondary heat stabilizer may be a phosphorus heat stabilizer. Preferably, the secondary heat stabilizer may include one or more selected from bis(dialkylphenyl)pentaerythritol diphosphite, phosphite, trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, (octyl)diphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, triphenyl phosphite, tris(butoxyethyl) phosphite, tris(nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropylidenediphenyl diphosphite, tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenol) diphosphite, tris(mono- and di-mixed nonylphenyl) phosphite, hydrogenated 4,4'-isopropylidenediphenol polyphosphite, phenyl(4,4'-isopropylidenediphenol)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris[4,4'-isopropylidene bis(2-tert-butylphenol)] phosphite, bis(isodecyl)phenyl phosphite, 4,4'-isopropylidene bis(2-tert-butylphenol) bis(nonylphenyl) phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 2-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1.3.2]-dioxaphosphor-6-yl)oxy]-N,N-bis[2-[(2,4,8,10-tetra-tert-butyl-dibenzo[d,f][1.3.2]-dioxaphosphept-6-yl)oxy]ethyl]-ethylamine, and 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1.3.2]-dioxaphosphepine, more preferably tris(2,4-di-tert-butylphenyl) phosphite (IF168).

[0179] The lubricant may preferably include one or more selected from aliphatic amide lubricants, fatty acid ester lubricants, and olefin waxes.

[0180] The aliphatic amide lubricants may preferably include one or more selected from stearamide, oleamide, erucamide, ethylene bisstearamide, and ethylene bisoleamide.

[0181] The fatty acid ester lubricant may preferably include one or more selected from fatty acid esters of an alcohol or a polyol, hydrogenated oils, butyl stearate, monoglyceryl stearate, pentaerythritol tetrastearate, stearyl stearate, ester waxes, and alkyl phosphates.

[0182] The olefin wax may preferably be a polyethylene wax.

[0183] Method for preparing a thermoplastic resin composition

[0184] The method for preparing a thermoplastic resin composition according to the present invention includes a step of kneading and extruding 100 parts by weight of a base resin and 3 parts by weight or more of a thermoplastic polyester elastomer (C) at 200 °C to 300 °C and 100 rpm to 500 rpm. The base resin contains 46% by weight to 81% by weight of an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19% by weight to 54% by weight of an aromatic vinyl compound - vinyl cyanide compound copolymer (B). The graft copolymer (A) contains an acrylic alkyl ester rubber having an average particle size of 50 nm to 150 nm. The copolymer (B) contains 10% by weight or more and less than 26% by weight of a vinyl cyanide compound and has a weight average molecular weight of 65,000 g / mol to 110,000 g / mol. The thermoplastic resin composition has an acrylic alkyl ester coverage value (X) of 65% by weight or more calculated by the following Equation 1. In this case, mechanical properties, weather resistance, and processability may be excellent. In addition, due to the excellent low whitening property even at a large thickness, an aesthetic appearance can be achieved. In addition, the composition of the present invention can be applied to an unpainted sheet, and economy and eco-friendliness may be excellent.

[0185] [Equation 1]

[0186] X = {(G - Y) / Y} × 100

[0187] In Equation 1, G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the acrylic alkyl ester content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0188] The method for preparing a thermoplastic resin composition has all the technical features of the above thermoplastic resin composition. Therefore, the description of the overlapping parts will be omitted.

[0189] The kneading and extrusion may preferably be carried out using an extruder at 200 °C to 300 °C, more preferably 210 °C to 260 °C, still more preferably 220 °C to 260 °C. Within this range, stable extrusion is possible and the mixing effect is excellent. At this time, the temperature is the temperature set in the cylinder.

[0190] For example, kneading and extrusion can be carried out at a screw rotation speed of 100 rpm to 500 rpm, preferably 150 rpm to 450 rpm, more preferably 200 rpm to 400 rpm. In this case, due to the appropriate production amount per unit time, the processing efficiency can be excellent.

[0191] For example, the thermoplastic resin composition obtained by extrusion can be made into pellets using a granulator.

[0192] Any extruder commonly used in the technical field to which the present invention pertains can be used in the present invention without any specific limitation. Preferably, a twin-screw extruder can be used.

[0193] Molded article

[0194] The molded article of the present invention includes the thermoplastic resin composition. In this case, the mechanical properties, processability, and weather resistance can be excellent. In addition, due to the excellent low whitening property even at a large thickness, an aesthetically pleasing appearance can be achieved. In addition, the molded article of the present invention can be applied to unpainted molded articles, and as a specific example, unpainted sheets. In addition, the economy and ecological friendliness can be excellent.

[0195] For example, the molded article can be an injection molded article, an extruded molded article, or a calendered molded article.

[0196] The injection molded article can preferably be an interior or exterior part of an automobile and a part for an electrical or electronic product.

[0197] The extruded molded article can preferably be a film, a sheet, or a foil, and specifically can be a decorative sheet, a finishing material for outdoor building materials, a roofing finishing material, an inner film, wallpaper, an edge band, vinyl coated metal (VCM), a flooring material, a PSP (plastic-steel-plastic) for molding, or a film for packaging.

[0198] The calendered molded article can preferably be a film, a sheet, or a foil, and specifically can be a decorative sheet, a finishing material for outdoor building materials, a roofing finishing material, an inner film, wallpaper, an edge band, vinyl coated metal (VCM), a flooring material, a PSP (plastic-steel-plastic) for molding, or a film for packaging.

[0199] The molded article can preferably be an unpainted sheet. In this case, the final product can be manufactured without a conventional painting process, resulting in cost savings and ecological friendliness.

[0200] The method for manufacturing a molded article may preferably include a step of obtaining an extrudate by kneading and extruding 100 parts by weight of a base resin and 3 parts by weight or more of a thermoplastic polyester elastomer (C) at 200°C to 300°C and 100 rpm to 500 rpm, and a step of manufacturing a molded article by molding the extrudate. The base resin contains 46% to 81% by weight of an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound - vinyl cyanide compound copolymer (B). The copolymer (A) contains an acrylic alkyl ester rubber having an average particle size of 50 nm to 150 nm. The copolymer (B) contains 10% or more and less than 26% by weight of a vinyl cyanide compound and has a weight average molecular weight of 65,000 g / mol to 110,000 g / mol. The extrudate has an acrylic alkyl ester coverage value (X) calculated by the following Equation 1 of 65% by weight or more. In this case, mechanical properties, processability, and weather resistance can be excellent. In addition, due to the excellent low whitening property even at a large thickness, an aesthetically pleasing appearance can be achieved. In addition, the composition of the present invention can be applied to an unpainted sheet, and economy and eco-friendliness can be excellent.

[0201] [Equation 1]

[0202] X = {(G - Y) / Y} × 100

[0203] In Equation 1, G represents the gel content (% by weight) based on the total weight of the thermoplastic resin composition, and Y represents the acrylic alkyl ester content (% by weight) in the gel based on the total weight of the thermoplastic resin composition.

[0204] For example, the extrudate may have a granular or plate shape.

[0205] In the present disclosure, there is no particular limitation on the plate shape as long as it is defined as the plate shape in the technical field to which the present invention pertains, and it may include, for example, a flat shape, a sheet shape, a film shape, etc.

[0206] In describing the thermoplastic resin composition of the present invention, the method for preparing the thermoplastic resin composition, and the molded article including the thermoplastic resin composition, it should be noted that other conditions or equipment not specifically described in this specification can be appropriately selected within the range that can be generally implemented in the art, without particular limitation.

[0207] Hereinafter, the present invention will be described in more detail with reference to the following preferred embodiments. However, these embodiments are provided for illustrative purposes only and should not be construed as limiting the scope and concept of the present invention. In addition, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the concept and scope of the present invention, and such changes and modifications are also within the scope of the appended claims.

[0208] [Examples]

[0209] The materials used in the examples and comparative examples are as follows.

[0210] *ASA graft copolymer (A-1): An ASA graft copolymer prepared by emulsion polymerization and containing an acrylic alkyl ester rubber with an average particle diameter of 100 nm (core: 38 wt% butyl acrylate and 7 wt% styrene, shell: 4 wt% butyl acrylate, 40 wt% styrene, and 11 wt% acrylonitrile, grafting degree: 70%).

[0211] *ASA graft copolymer (A-2): An ASA graft copolymer prepared by emulsion polymerization and containing an acrylic alkyl ester rubber with an average particle diameter of 100 nm (core: 45 wt% butyl acrylate, shell: 44 wt% styrene, and 11 wt% acrylonitrile, grafting degree: 50%).

[0212] *ASA graft copolymer (A-3): An ASA graft copolymer prepared by emulsion polymerization and containing an acrylic alkyl ester rubber with an average particle diameter of 120 nm (core: 38 wt% butyl acrylate and 7 wt% styrene, shell: 4 wt% butyl acrylate, 40 wt% styrene, and 11 wt% acrylonitrile, grafting degree: 70%).

[0213] *SAN copolymer (B-1): A styrene-acrylonitrile copolymer containing 20 wt% acrylonitrile and having a weight-average molecular weight of 80,000 g / mol

[0214] *SAN copolymer (B-2): A styrene-acrylonitrile copolymer containing 20 wt% acrylonitrile and having a weight-average molecular weight of 40,000 g / mol

[0215] *SAN copolymer (B-3): A styrene-acrylonitrile copolymer containing 20 wt% acrylonitrile and having a weight-average molecular weight of 180,000 g / mol

[0216] *SAN copolymer (B-4): A styrene-acrylonitrile copolymer containing 20 wt% acrylonitrile and having a weight-average molecular weight of 150,000 g / mol

[0217] *SAN copolymer (B-5): A styrene-acrylonitrile copolymer containing 27 wt% acrylonitrile and having a weight-average molecular weight of 150,000 g / mol

[0218] *SAN copolymer (B-6): A styrene-acrylonitrile copolymer containing 5 wt% acrylonitrile and having a weight-average molecular weight of 110,000 g / mol

[0219] *TPEE (C): A thermoplastic polyester elastomer having a melt flow rate (230 °C, 2.16 kg) of 5 g / 10 min and a Shore D hardness of 40D (Product name: KEYFLEX BT2140D, Manufacturer: LG Chemical Co.)

[0220] Examples 1 to 9 and Comparative Examples 1 to 9

[0221] According to the content shown in Table 1 and Table 2 below, the components shown in Table 1 and Table 2 were introduced into a twin-screw extruder, and melt-kneaded and extruded at 230 °C and 150 rpm to obtain pellets. The obtained pellets were injection-molded at 220 °C to prepare specimens.

[0222] In addition, the obtained pellets were extruded using a T-die extruder (single screw, 20Τ, L / D = 25, Collins Co.) at an extrusion screw speed of 100 rpm, an extrusion temperature of 220 °C, a three-roll temperature of 85 °C, and a roll rotation speed of 1.5 m / min to obtain a sheet with a thickness of 0.3 mm, and its physical properties were measured.

[0223] [Test Example]

[0224] The properties of the pellets or specimens obtained from Examples 1 to 9 and Comparative Examples 1 to 9 were measured by the following methods, and the results are shown in Table 1 and Table 2 below.

[0225] Measurement method

[0226] *Alkyl acrylate coverage value (X value, wt%) of the thermoplastic resin composition: The alkyl acrylate coverage value was calculated by the following Equation 1.

[0227] [Equation 1]

[0228] X = {(G - Y) / Y} × 100

[0229] In Equation 1, G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

[0230] Here, use 1The content of alkyl acrylate in the gel is quantitatively measured by an NMR analyzer or FT-IR. The specific measurement conditions are as follows.

[0231] 1 1H NMR

[0232] - Equipment name: Bruker 600MHz NMR (AVANCE III HD) CPP BB (1H 19F tunable and broadband, with z-gradient) Prodigy probe

[0233] - Measurement conditions: 1H NMR (zg30): ns = 32, d1 = 5s, TCE-d2, at room temperature.

[0234] FT - IR

[0235] - Equipment name: Agilent Cary 66

[0236] - Measurement conditions: ATR mode

[0237] * Gel content (%): When measuring the gel content, 1 g of the particles obtained by extruding the thermoplastic resin composition is added to 30 ml of acetone, and then stirred at 210 rpm and room temperature for 12 hours using an orbital shaker (equipment name: Lab companion SKC-6075). Then, centrifugation is performed at 0 °C and 18,000 rpm for 3 hours using a centrifuge (Supra R30, Hanil Science Co.) to separate the insoluble substances that are not dissolved in acetone, and then dried by forced circulation in a forced convection oven (equipment name: Lab companion OF-12GW) set at 85 °C for 12 hours. Then, the weight of the insoluble substances is measured, and the gel content is calculated by Equation 4 below.

[0238] [Equation 4]

[0239] Gel content (wt%) = [weight of insoluble substances (gel) (g) / weight of sample (g)] × 100

[0240] Grafting degree (%): 0.5 g of the powdered graft polymer is added to 50 ml of acetone, stirred at room temperature for 12 hours, centrifuged to separate only the insoluble substances that are not dissolved in acetone, and the separated insoluble substances are dried for 12 hours. Then, the weight of the dried insoluble substances is measured, and the grafting degree is calculated by Equation 2 below.

[0241] [Equation 2]

[0242] Grafting degree (%) = [weight of graft monomer (g) / weight of rubber (g)] × 100

[0243] In Equation 2, the weight (g) of the graft monomer is obtained by subtracting the weight of the rubber (g), which is the weight (g) of the rubber component theoretically added to the graft copolymer powder, from the weight of the insoluble matter (gel) obtained by dissolving the graft copolymer in acetone and centrifuging.

[0244] As a specific measurement example, when measuring the weight (g) of the insoluble matter (gel), 0.5 g of powdered graft copolymer is added to 50 ml of acetone, and then stirred using an orbital shaker (equipment name: Lab companion SKC-6075) at 210 rpm and room temperature for 12 hours. Then, centrifugation is performed at 0 °C and 18,000 rpm for 3 hours using a centrifuge (Supra R30, Hanil Science Co.) to separate the insoluble matter that is not dissolved in acetone, and then dried by forced circulation in a forced convection oven (equipment name: Lab companion OF-12GW) set at 85 °C for 12 hours. Then, the weight of the insoluble matter (gel) is measured.

[0245] * Color difference (ΔE): After cup-pressing the central part of a 0.3-mm-thick sheet to a depth of 8 mm at a speed of 10 mm / min using a 20-mm-diameter ball and an electric Erichsen cupping testing machine, the values before and after cup-pressing are measured using a color difference meter, and the color difference (ΔE) is calculated by the following Equation 3. As ΔE decreases, the low whitening property is improved.

[0246] [Equation 3]

[0247]

[0248] In Equation 3, L', a', and b' respectively represent the L, a, and b values measured using the CIE LAB color coordinate system after cup-pressing, and L0, a0, and b0 respectively represent the L, a, and b values measured using the CIE LAB color coordinate system before cup-pressing.

[0249] * Tensile strength (kgf / cm 2 ) and elongation at break (%): According to ASTM D638, the tensile strength and elongation at break are measured using an injection specimen with a thickness of 3 mm at a crosshead speed of 50 mm / min.

[0250] * Flexural strength (kgf / cm 2 ):According to ASTM D790, the flexural strength is measured using an injection specimen with a thickness of 3 mm at a span of 50 mm and a test speed of 10 mm / min.

[0251] *Hardness: Rockwell hardness is measured on the R-scale according to ASTM D785.

[0252] *Processability: The blistering characteristics and dimensional stability are measured and evaluated according to the following criteria.

[0253] ○: Both blistering characteristics and dimensional stability are excellent.

[0254] X: Poor blistering characteristics, poor dimensional stability, or both.

[0255] - Blistering characteristics: When extruding a 0.3 mm thick sheet to a length of 1 m or more using a T-die extruder without blistering, it is evaluated as excellent.

[0256] - Dimensional stability: After extruding a 0.3 mm thick sheet to a length of 1 m or more using a T-die extruder, the width and thickness of the sheet are measured at more than 10 positions. When the deviation is within ±10%, it is evaluated as excellent.

[0257] [Table 1]

[0258]

[0259] [Table 2]

[0260]

[0261]

[0262] -: Unable to measure

[0263] As shown in Table 1 and Table 2, compared with Comparative Examples 1 to 9, in the case of the thermoplastic resin compositions of Examples 1 to 9 according to the present invention, the color difference in the thick sheet is greatly reduced, indicating excellent low whitening characteristics. In addition, the tensile strength, elongation, flexural strength, hardness, and processability are excellent.

[0264] On the other hand, in the case of Comparative Example 1 containing an excessive amount of ASA graft copolymer (A-1) and a small amount of SAN copolymer (B-1), the flexural strength is low and the hardness cannot be measured. In the case of Comparative Example 2 containing a small amount of ASA graft copolymer (A-1) and an excessive amount of SAN copolymer (B-1), the color difference increases significantly, so the low whitening characteristics are poor. In addition, the elongation is very low.

[0265] In addition, in the case of Comparative Example 3 containing ASA graft copolymer (A-2), the color difference increases greatly, indicating poor low whitening characteristics.

[0266] In addition, in Comparative Examples 4 to 7, which respectively contain SAN copolymers (B-2), SAN copolymers (B-3), SAN copolymers (B-4), and SAN copolymers (B-5) that do not meet the acrylonitrile content and / or weight average molecular weight range of the SAN copolymer (B), the processability is reduced or the color difference increases, resulting in poor low whitening properties.

[0267] In addition, in Comparative Example 8 where the TPEE (C) is not included, the color difference increases significantly, indicating very poor low whitening properties.

[0268] In addition, in Comparative Example 9 where the SAN copolymer (B-6) that does not meet the acrylonitrile content of the SAN copolymer (B) is included, the tensile strength and flexural strength are significantly reduced, and the hardness is also reduced.

[0269] In addition, the following Figure 1 shows images taken after cupping using an electric Erichsen cupping tester for a sheet made of the thermoplastic resin composition according to Example 1 of the present invention and a sheet made of the thermoplastic resin composition of Comparative Example 1. Since whitening did not occur compared to Comparative Example 1, it was confirmed that Example 1 has excellent low whitening properties.

[0270] In summary, when a thermoplastic resin composition is prepared by including a base resin and a thermoplastic polyester elastomer at a predetermined content ratio, and the acrylic alkyl ester coverage value of the thermoplastic resin composition is adjusted within a predetermined range, wherein the base resin includes an acrylic alkyl ester - aromatic vinyl compound - vinyl cyanide compound graft copolymer containing rubber having a predetermined average particle size according to the present invention and an aromatic vinyl compound - vinyl cyanide compound copolymer containing a predetermined content of vinyl cyanide compound and having a predetermined weight average molecular weight, the thermoplastic resin composition exhibits excellent mechanical properties, processability, and weather resistance. In addition, even in thick sheets, the low whitening properties are excellent. Therefore, an aesthetic appearance is achieved. In addition, the thermoplastic resin composition of the present invention can be applied to unpainted molded articles, as a specific example, unpainted sheets. In addition, it is excellent in economy and eco-friendliness.

Claims

1. A thermoplastic resin composition comprising: 100 parts by weight of a base resin, the base resin comprising 46 to 81 wt % of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) and 19 to 54 wt % of an aromatic vinyl compound-vinyl cyanide compound copolymer (B), the graft copolymer (A) comprising an alkyl acrylate rubber having an average particle diameter of 50 to 150 nm, the copolymer (B) comprising 10 wt % or more and less than 26 wt % of a vinyl cyanide compound and having a weight average molecular weight of 65,000 to 110,000 g / mol; and 3 parts by weight or more of a thermoplastic polyester elastomer (C), in, The thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65 wt % or more calculated by the following Equation 1, [Equation 1] X = {(GY) / Y} × 100, Herein, G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

2. The thermoplastic resin composition according to claim 1, wherein The graft copolymer (A) includes 20 to 60 wt % of an alkyl acrylate rubber and 40 to 80 wt % of an aromatic vinyl compound-vinyl cyanide compound copolymer surrounding the alkyl acrylate rubber, based on the total weight of the graft copolymer (A).

3. The thermoplastic resin composition according to claim 1, wherein The graft copolymer (A) has a grafting degree of 60% or more calculated by the following equation 2, [Equation 2] Grafting degree (%) = [grafting monomer weight (g) / rubber weight (g)] × 100, The weight (g) of the grafted monomer is obtained by subtracting the weight (g) of the rubber from the weight of the insoluble matter (gel) obtained by dissolving the grafted copolymer in acetone and centrifuging it, and the weight (g) of the rubber is the weight (g) of the rubber component theoretically added to the grafted copolymer powder.

4. The thermoplastic resin composition according to claim 1, wherein The thermoplastic polyester elastomer (C) has a melt flow rate of 0.5 to 10 g / 10 min measured at a temperature of 230° C. under a load of 2.16 kg according to ASTM D1238.

5. The thermoplastic resin composition according to claim 1, wherein The thermoplastic polyester elastomer (C) is an elastomer comprising an aromatic dicarboxylic acid or an ester derivative thereof, an aliphatic diol and a polyalkylene oxide.

6. The thermoplastic resin composition according to claim 5, wherein The aromatic dicarboxylic acid includes one or more selected from terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid and 1,4-cyclohexane dicarboxylic acid.

7. The thermoplastic resin composition according to claim 5, wherein The aliphatic diol includes one or more selected from ethylene glycol, propylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol and 1,4-cyclohexanedimethanol.

8. The thermoplastic resin composition according to claim 5, wherein The polyalkylene oxide includes one or more selected from polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexamethylene glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide addition polymer of polypropylene glycol, and a copolymer of ethylene oxide and tetrahydrofuran.

9. The thermoplastic resin composition according to claim 1, wherein After the central portion of a sheet having a thickness of 0.3 mm is cupped to a depth of 8 mm at a speed of 10 mm / min using a 20 mm diameter ball and an electric Erichsen cupping tester, when the values ​​before and after cupping are measured using a colorimeter and the color difference (ΔE) is calculated by the following Equation 3, the thermoplastic resin composition has a color difference (ΔE) of 2.0 or less, [Equation 3] Wherein, L', a' and b' respectively represent the L, a and b values ​​measured using the CIE LAB color coordinate system after cupping, and L0, a0 and b0 respectively represent the L, a and b values ​​measured using the CIE LAB color coordinate system before cupping.

10. The thermoplastic resin composition according to claim 1, wherein The thermoplastic resin composition has a Rockwell hardness of 44 or more measured on an R-scale according to ASTM D785.

11. A method for preparing a thermoplastic resin composition, comprising kneading and extruding 100 parts by weight of a base resin and 3 parts by weight or more of a thermoplastic polyester elastomer (C) at 200° C. to 300° C. and 100 rpm to 500 rpm, wherein the base resin comprises 46% to 81% by weight of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) and 19% to 54% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (B), wherein the graft copolymer (A) comprises an alkyl acrylate rubber having an average particle diameter of 50 nm to 150 nm, and the copolymer (B) comprises 10% by weight or more and less than 26% by weight of a vinyl cyanide compound and has a weight average molecular weight of 65,000 g / mol to 110,000 g / mol, in, The thermoplastic resin composition has an alkyl acrylate coverage value (X) of 65 wt % or more calculated by the following Equation 1, [Equation 1] X = {(GY) / Y} × 100, Herein, G represents the gel content (wt%) based on the total weight of the thermoplastic resin composition, and Y represents the alkyl acrylate content (wt%) in the gel based on the total weight of the thermoplastic resin composition.

12. A molded article comprising the thermoplastic resin composition according to any one of claims 1 to 10.

13. The molded article according to claim 12, wherein The moldings are unpainted sheets.

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