Polyester resin composition, method for preparing the same, and molded article

Abstract

The present invention relates to a polyester resin composition, a method for preparing the polyester resin composition, and a molded article manufactured using the polyester resin composition. The polyester resin composition according to the present invention can have excellent large-area and low-strain characteristics by using a large-area low-strain material as a raw material, satisfies physical property balance among mechanical properties, fluidity and thermal stability, inhibits fogging even at high temperatures, and has excellent heat resistance and heat resistance. Thus, excellent product reliability and appearance are provided for a molded article manufactured using the polyester resin composition.

Description

Technical Field

[0001] [Cross-references to related applications] This application claims priority to Korean Patent Application No. 10-2024-0127364, filed on September 20, 2024, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

[0002] This invention relates to a polyester resin composition; a method for preparing the polyester resin composition; and a molding article manufactured using the polyester resin composition. More specifically, this invention relates to: a polyester resin composition that exhibits excellent large-area, low-strain characteristics by using a large-area, low-strain material as a raw material, achieving a balance between physical properties, flowability, and thermal stability, suppressing fogging even at high temperatures, and providing excellent product reliability and appearance for molding articles manufactured using the polyester resin composition; a method for preparing the polyester resin composition; and a molding article manufactured using the polyester resin composition. Background Technology

[0003] In the past, when manufacturing housings for automotive interior components such as dashboards and navigation systems, composite materials made by reinforcing polybutylene terephthalate (PBT) resin with glass fibers were mainly used to improve electrical insulation properties, reduce weight, and lower manufacturing costs.

[0004] Recently, issues have arisen regarding the development of materials for new, thin, large-screen dashboards and navigation systems, including the development of 25-inch head-up display (HUD) screens, which are more than twice the size of existing 12-inch screens. Preventing warping is a critical factor for these materials, and in this composite material, the crystal formation of polybutylene terephthalate resin and the anisotropy of glass fibers may have a negative impact.

[0005] Therefore, to apply this composite material to new large screens, thin-walled dashboards, and navigation systems, low-strain materials are being developed by alloying various resins such as ABS, ASA, and PC with PBT. However, it is difficult to simultaneously achieve the excellent low deformation and thermal stability, as well as high-temperature fogging prevention, which are essential properties for housings that can be used in 25-inch head-up displays (HUDs). Therefore, there is a need to develop a composite material that can achieve the above properties simultaneously.

[0006] [Related Technical Documents] [Patent Literature] Japanese Patent Application Publication No. 2019-151811 (Publication Date: September 12, 2019) Summary of the Invention

[0007] Technical issues Therefore, the present invention has been made in view of the above-mentioned problems, and one object of the present invention is to provide a polyester resin composition and a method thereof that can achieve a good balance of mechanical strength, flowability, thermal stability and physical properties at low cost, without warping in large-area components.

[0008] Another object of the present invention is to provide a molded article having high-temperature anti-fogging capability manufactured using the polyester resin composition.

[0009] The above and other objectives can be achieved by the invention described below.

[0010] Technical solution I) According to one aspect of the present invention, a polyester resin composition is provided, comprising a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound-vinyl cyanide compound; and a fiber reinforcing agent. Specifically, when the MD direction length (unit: mm) and TD direction length (unit: mm) are measured by lifting tests, and the value (TD / MD) is obtained by dividing the TD direction length by the MD direction length, the polyester resin composition has a value (TD / MD) of 1.60 or less. The polyester resin composition has a haze of less than 10.0 as measured by a fogging test (150°C, 5 hours).

[0011] II) According to I), the polyester resin may be a polyalkylene terephthalate resin.

[0012] III) According to I) to II), the polyester resin may have an intrinsic viscosity (η) of 0.7 dl / g to 0.9 dl / g.

[0013] IV) According to I) to III), based on a total of 100% by weight of the polyester resin composition, the polyester resin may be contained in an amount of more than 56% by weight.

[0014] V) According to I) to IV), the ungrafted copolymer may contain more than 20% by weight of a vinyl cyanide compound.

[0015] VI) According to I) to V), the ungrafted copolymer may have a heat distortion temperature of above 96.5°C as measured in ASTM D648 at 18.6 kgf and a melt index of 28 to 32 as measured in ASTM D1238 (220°C, 10 kgf).

[0016] VII) According to I) to VI), based on a total of 100% by weight of the polyester resin composition, the ungrafted copolymer may be included in an amount of less than 12% by weight.

[0017] VIII) According to I) to VII), the fiber reinforcing agent may be glass fiber.

[0018] IX) According to I) to VIII), the glass fiber may contain SiO2, CaO and Al2O3, and the SiO2 content may be greater than the sum of the CaO and Al2O3 contents.

[0019] X) According to I) to IX), the glass fiber may contain 50% to 55% by weight of SiO2, 15% to 21% by weight of Al2O3 and 13% to 19% by weight of CaO.

[0020] XI) According to I) to X), based on a total of 100% by weight of the polyester resin composition, the fiber reinforcing agent may be included in an amount of 20% to 40% by weight.

[0021] XII) According to I) to XI), the polyester resin composition may contain antioxidants and / or lubricants, and based on a total of 100% by weight of the polyester resin, the ungrafted copolymer, the fiber reinforcing agent, the antioxidant, and the lubricant, the antioxidant and the lubricant may each be contained in an amount from 0.1% by weight to 10% by weight.

[0022] XIII) According to I) to XII), based on a total of 100 parts by weight of the polyester resin, the ungrafted copolymer, the fiber reinforcing agent, the antioxidant, and the lubricant, the polyester resin composition may contain 0.1 to 10 parts by weight of colorant.

[0023] XIV) According to I) to XIII), the polyester resin composition may have a high load heat distortion temperature of 190°C or higher at 1.82 MPa as measured according to ISO 75 100, and may have a flexural strength of 180 MPa or higher and a flexural modulus of 8000 MPa or higher as measured according to ISO 178 using a 4.0 mm specimen and SPAN64 at a rate of 2 mm / min.

[0024] According to XV) I) to XIV), when the lift distance from the floor to the four corners is measured using a square specimen with dimensions of 100mm × 100mm × 1.56mm according to the low strain evaluation method, the polyester resin composition can have a maximum lift height of less than 5.0mm.

[0025] XVI) According to another aspect of the present invention, a polyester resin composition is provided, comprising a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound-vinyl cyanide compound; and a fiber reinforcing agent. The polyester resin composition wherein the haze measured by a fogging test (150°C, 5 hours) is below 10.0.

[0026] XVII) According to another aspect of the invention, a polyester resin composition is provided, comprising a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound-vinyl cyanide compound; and a fiber reinforcing agent. The ungrafted copolymer has an MI value greater than 28 and less than 32, and the content of the ungrafted copolymer is less than 12% by weight.

[0027] XVIII) According to another aspect of the present invention, a method for preparing a polyester resin composition is provided, the method comprising kneading and extruding a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound and a vinyl cyanide compound; and a fiber reinforcing agent. Wherein, when the MD direction length (unit: mm) and TD direction length (unit: mm) are measured using a shrinkage sample (size: 60mm×60mm×2mm), and the value (TD / MD) is calculated by dividing the TD direction length (unit: mm) by the MD direction length (unit: mm), the polyester resin composition has a value (TD / MD) of 1.60 or less, and the polyester resin composition has a haze of 10.0 or less as measured by a haze test (150°C, 5 hours).

[0028] According to another aspect of the present invention, a molding article comprising the above-described polyester resin composition is provided.

[0029] According to XIX), the molded article can be an automotive interior part housing.

[0030] According to XXI) to XIX) to XX), the automotive interior components may include dashboards, navigation systems, etc.

[0031] According to XIX) to XXI), the automotive interior trim may be a large-screen head-up display (HUD) larger than 12 inches.

[0032] Beneficial effects The polyester resin composition according to the present invention can provide a molded article having excellent large-area, low-strain characteristics; a physical property balance between mechanical properties and thermal stability equal to or better than conventional large-area, low-strain alloy polyester materials; excellent processability due to improved melt flow index; and improved product reliability and appearance.

[0033] That is, the molded articles made using the polyester resin composition according to the present invention have excellent large area, low strain characteristics and excellent balance between mechanical properties such as tensile strength and flexural strength and thermal stability, and can provide high-temperature anti-fogging capability, thereby achieving product reliability and appearance.

[0034] Therefore, the molded articles according to the present invention are more suitable for large-area thin dashboards and large-area components of navigation systems. Attached Figure Description

[0035] Figure 1 The apparatus and process for testing high-temperature anti-fogging capabilities are shown. Detailed Implementation

[0036] The invention will be described in more detail below to aid in understanding it.

[0037] The terms and words used in this specification and the appended claims should not be construed as limited to their common or dictionary meanings, but should be interpreted as having meanings and concepts that match the technical concept of the invention in order to best describe the invention.

[0038] In this specification, a polymer comprising a particular compound means a polymer prepared by polymerizing that compound, and the units in the polymer are derived from that compound.

[0039] Unless otherwise stated, all figures, values, and / or expressions relating to the amounts of components, reaction conditions, polymer compositions, and formulations used in this specification should be understood as being defined by the term "about." This is because these figures are inherently approximate and reflect various uncertainties in measurement that arise when obtaining these values. Furthermore, when numerical ranges are disclosed in this disclosure, unless otherwise stated, such ranges are continuous and include all values ​​from the minimum to the maximum of such ranges. Additionally, when such ranges refer to integers, unless otherwise stated, they include all integers from the minimum to the maximum.

[0040] In this disclosure, when a range is specified for a variable, it should be understood that the variable includes all values ​​within the range that includes the endpoints of the range. For example, the range “5 to 10” includes values ​​of 5, 6, 7, 8, 9, and 10, any subranges such as 6 to 10, 7 to 10, 6 to 9, and 7 to 9, and any values ​​among integers that fit within ranges such as 5.5 to 8.5 and 6.5 to 9. Furthermore, the range 10% to 30% includes values ​​such as 10%, 11%, 12%, and 13%, all integers up to 30%, and any values ​​among all reasonable integers within ranges such as 10.5%, 15.5%, and 25.5%.

[0041] In this disclosure, unless otherwise stated, the terms "MD, TD measured by lift test" refer to a type of low-strain assessment method. MD, TD measured by lift test means that after producing a shrinkage specimen with dimensions of 60 mm × 60 mm × 2 mm, the specimen is stored in a constant temperature / humidity chamber at 23°C / 50% RH for more than 24 hours, the specimen is fixed with a clamp to be horizontally aligned with the bottom surface and the specimen, and the length in the MD direction (in mm) and the length in the TD direction (in mm) are measured.

[0042] In this disclosure, unless otherwise stated, the term "haze measured by a fogging test" refers to a type of low-strain assessment method in which a square specimen with dimensions of 100 mm × 100 mm × 1.5 mm is manufactured, then cut into 10 g pieces, and referenced... Figure 1 The measurements are performed according to the equipment and process description shown.

[0043] Specifically, before placing the 10g sample into the test tube, check for any residual material in the test tube and wipe the inside of the test tube and the transparent glass plate three times with a 70% ethanol solution. Since ethanol may remain in the test tube, dry it with a hair dryer before use.

[0044] The test specimens were dried at 120°C for 2 to 4 hours before measurement, and then stored in a constant temperature / humidity room at 23°C / 50%RH for more than 24 hours before use.

[0045] Once the test tube and transparent glass plate are prepared, place 10g of the sample into the test tube and seal the opening with the transparent glass plate. Set the measurement temperature (150℃) and cooling temperature (23℃), and immerse the test tube in the [temperature range]. Figure 1 The device was used for 5 hours, and the haze value of the glass plate was measured using a haze meter.

[0046] When measuring haze, the haze value is measured in three parts: the central portion of the glass plate, the left side based on the center, and the right side based on the center. The average value is recorded as the haze value of the sample. A lower haze value indicates less fogging.

[0047] Unless otherwise stated, the term "melt flow index" as used in this specification can be the melt flow index measured at 265°C under a load of 2.16 kg according to ISO 1133.

[0048] In this disclosure, the content (by weight %) of units in a polymer, monomer, or block may refer to the content (by weight %) of the derived monomer.

[0049] In this disclosure, the content (weight %) of units in polymers, monomers or blocks can be measured using measurement methods commonly used in the art to which this invention pertains, or the content of added monomers can be defined as the content of units in polymers prepared under the premise that all monomers are polymerized.

[0050] The inventors have confirmed that when using low-strain polyester materials as novel large-screen thin-walled automotive interior component materials, and when preparing composite materials containing polyester resin to provide material rigidity and thermal stability, and when controlling the content of aromatic vinyl compounds—vinyl cyanide compounds—that constitute the non-grafted copolymer while including fiber reinforcing agents, excellent physical property balance is achieved between mechanical properties, flowability, thermal stability, and high-temperature anti-fogging capabilities, resulting in both product reliability and appearance. Based on these results, the inventors conducted further research to complete this invention.

[0051] Polyester resin composition A polyester resin composition according to one embodiment of the present invention comprises a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound-vinyl cyanide compound; and a fiber reinforcing agent.

[0052] Polyester resin Polyester resins impart moldability to resin compositions containing them and impart thermal stability to molded articles made using them.

[0053] For example, the polyester resin can be a polyalkylene terephthalate resin, preferably a polybutylene terephthalate resin.

[0054] Polyester resin is a crystalline resin and prevents chemicals from penetrating from the outside. Furthermore, due to its crystalline structure, the flowability of polyester resin compositions containing polyester resin can be improved during injection molding, thereby improving the appearance.

[0055] Polybutylene terephthalate (PBT) resin can have repeating units represented by the following chemical formula 1.

[0056] [Chemical Formula 1] In chemical formula 1, n represents the average degree of polymerization, which is between 50 and 200.

[0057] In one embodiment of the invention, to increase the impact strength of the polyester resin composition, a copolymer resin obtained by copolymerizing polybutylene terephthalate resin with an impact-improving compound such as polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, aliphatic polyester, or aliphatic polyamide, or a modified polybutylene terephthalate resin obtained by mixing polybutylene terephthalate resin with an impact-improving compound, can be used.

[0058] For example, polyester resins, preferably polybutylene terephthalate resins, can have a weight-average molecular weight of 10,000 g / mol to 80,000 g / mol, 20,000 g / mol to 100,000 g / mol, 30,000 g / mol to 90,000 g / mol, 40,000 g / mol to 80,000 g / mol, or 50,000 g / mol to 80,000 g / mol. Within this range, mechanical properties can be improved.

[0059] When measuring the weight-average molecular weight, a 1% by weight sample was prepared by placing tetrahydrofuran (THF) and the compound in a 1 ml glass vial. After filtering the standard sample (polystyrene) and the sample through a filter (pore size: 0.45 μm), the filtered sample was injected into a GPC injector. The weight-average molecular weight and molecular weight distribution of the compound were then obtained by comparing the elution time of the sample with the calibration curve of the standard sample. An Infinity II 1260 (Agilient Co.) was used as the measuring instrument, with a flow rate set to 1.00 mL / min and a column temperature set to 40.0 °C.

[0060] For example, based on a total of 100% by weight of a polyester resin composition (polyester resin + ungrafted copolymer + fiber reinforcing agent), the polyester resin may be included in an amount of 56% by weight or more; or the polyester resin composition may include antioxidants and lubricants, and based on a total of 100% by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the polyester resin may be included in an amount of 56% by weight or more. When the content is less than this range, the high-temperature anti-fogging ability may decrease as the amount of ungrafted copolymer used increases. When the content exceeds this range, a decrease in the amount of ungrafted copolymer used may lead to a decrease in the ability to prevent warping, or a decrease in the amount of fiber reinforcing agent used may lead to an overall deterioration of physical properties.

[0061] As a specific example, based on a total of 100% by weight of polyester resin composition, polyester resin may be included in an amount of 57.5% by weight to 90% by weight; or when the polyester resin composition includes antioxidants and lubricants, based on a total of 100% by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant and lubricant, polyester resin may be included in an amount of 57.5% by weight to 90% by weight.

[0062] Preferably, based on a total of 100% by weight of the polyester resin composition, the polyester resin may be included in an amount of 58% by weight to 80% by weight; or when the polyester resin composition includes antioxidants and lubricants, based on a total of 100% by weight of the polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the polyester resin may be included in an amount of 58% by weight to 80% by weight.

[0063] Polyester resins, preferably polybutylene terephthalate resins, can have intrinsic viscosities (η) of 0.7 dl / g to 0.9 dl / g or 0.75 dl / g to 0.85 dl / g. When the intrinsic viscosity is below this range, the effect of enhancing physical properties may be reduced, and consequently, the effect of improving non-halogen thermal stability may be negligible. When the intrinsic viscosity exceeds this range, molding properties may deteriorate, resulting in a poorer appearance of the parts.

[0064] In this disclosure, when measuring intrinsic viscosity, unless otherwise specified, a sample solution with a concentration of 0.05 g / ml is prepared by completely dissolving the sample in dichloromethane as a solvent, followed by filtration to obtain a filtrate. The intrinsic viscosity is then measured at 20°C using an Ubbelohde viscometer with the obtained filtrate.

[0065] There are no particular restrictions on the method for preparing polyester resin, as long as the method is a polymerization method commonly practiced in the technical field to which this invention pertains. Commercially available polyester resin can be used, as long as the commercially available polyester resin meets the definition of resin according to this invention.

[0066] non-grafted copolymers In this disclosure, an ungrafted copolymer (hereinafter referred to as SAN) is used to address warpage caused by crystal formation of polyester resin and to supplement the rigidity of internal components.

[0067] For example, an ungrafted copolymer can be an aromatic vinyl compound-vinyl cyanide compound copolymer.

[0068] As a specific example, the non-grafted copolymer may be a copolymer comprising 60% to 80% by weight of an aromatic vinyl compound and 20% to 40% by weight of a vinyl cyanide compound, preferably a copolymer comprising 65% to 75% by weight of an aromatic vinyl compound and 25% to 35% by weight of a vinyl cyanide compound.

[0069] The aromatic vinyl compounds contained in the non-graft copolymer may include common aromatic vinyl compounds that can be used in this invention, such as styrene, but are not limited to including only specific aromatic vinyl compounds.

[0070] Furthermore, the vinyl cyanide compounds included in the non-graft copolymer may include common vinyl cyanide compounds that can be used in this invention, such as acrylonitrile, but are not limited to including only specific vinyl cyanide compounds.

[0071] Therefore, the non-grafted copolymer can be a resin polymerized from components within the above-mentioned specific content range, and preferably can be a styrene-acrylonitrile (SAN) resin capable of improving the rigidity of automotive interior parts.

[0072] For example, ungrafted copolymers can have a heat distortion temperature (HDT) of ≥96.5°C as measured in ASTM D648 at 18.6 kgf, and can have a melt index of 28 to 32 (220°C, 10 kgf) as measured in ASTM D1238. In this case, excellent molding properties can be provided while maintaining the heat resistance of the polyester resin composition.

[0073] As a specific example, the ungrafted copolymer can have a heat distortion temperature (HDT) of 97°C to 100°C as measured in ASTM D648 at 18.6 kgf, and can have a melt index of 28 to 30 (220°C, 10 kgf) as measured in ASTM D1238. In this case, the heat resistance of the polyester resin composition can be maintained while providing excellent molding properties.

[0074] For example, when measuring gas mass using GC / MS (T-VOC, 250°C / 10 min purge & trap), the ungrafted copolymer may have a styrene content of less than 200 ppm, preferably less than 150 ppm, more preferably 1 ppm to 130 ppm, and / or may have an ethylbenzene content of less than 50 ppm, preferably 10 ppm, more preferably 1 ppm to 5 ppm, and / or may have a toluene content of less than 55 ppm, preferably less than 53 ppm, more preferably 1 ppm to 53 ppm. In this case, the occurrence of haze in the polyester resin composition can be minimized.

[0075] For example, when measuring gas mass using GC / MS (T-VOC, 250°C / 10 min purge & trap), the content of xylene, isopropylbenzene, propylbenzene, benzaldehyde, α-methylstyrene, tert-butylbenzene, n-butylbenzene, sec-butylbenzene, phenylacetaldehyde, acetophenone, cumyl alcohol, 1,2-dicyanocyclobutane, phenylbutyronitrile, erucamide, and C12 hydrocarbons in the ungrafted copolymer may be less than 10 ppm, or these gases may be undetectable. In this case, the occurrence of haze in the polyester resin composition can be minimized.

[0076] For example, using GC / MS measurement, the ungrafted copolymer can have an oligomer content of less than 500 ppm, preferably 350 ppm, more preferably 1 ppm to 250 ppm. In this case, the occurrence of haze in the polyester resin composition can be minimized.

[0077] In this disclosure, "oligomer" follows the definition commonly used in the art to which this invention pertains. As a specific example, an oligomer can be derived from monomers having a relatively low molecular weight, and can also refer to a molecule having a relatively medium molecular weight, consisting of 2 to 20 monomer units. A "molecule having a relatively medium molecular weight" is a molecule whose properties are not significantly altered when one or more monomer units are removed.

[0078] Regarding gas quality, Comparative Example 2 described below corresponds to an experiment using a non-grafted copolymer (B2) prepared by a single degassing treatment after initiator polymerization, and Comparative Example 3 corresponds to an experiment using a non-grafted copolymer (B3) prepared by two degassing treatments after thermal polymerization. Compared to the example using a non-grafted copolymer (B1) prepared by two degassing treatments after initiator polymerization, the comparative examples demonstrated relatively poor gas quality, making it difficult to meet haze characteristics.

[0079] As long as the required gas quality is met, the ungrafted copolymer can be prepared by polymerization methods commonly practiced in the technical field to which this invention pertains without any particular limitations. Commercially available products can be used, provided that the product meets the gas quality requirements for the ungrafted copolymer according to this invention.

[0080] For example, based on a total of 100% by weight of polyester resin composition, the non-grafted copolymer may be included in an amount of 12% by weight or less; or when the polyester resin composition includes antioxidants and lubricants, based on a total of 100% by weight of polyester resin, non-grafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the non-grafted copolymer may be included in an amount of 12% by weight or less. When the content of the non-grafted copolymer is less than this range, the rigidity of automotive interior parts manufactured using composite resin compositions containing non-grafted copolymers may be poor, and the ability to prevent warping may be reduced. When the content of the non-grafted copolymer exceeds this range, the heat resistance and impact resistance of automotive interior parts manufactured using composite resin compositions containing non-grafted copolymers may be poor, and the high-temperature anti-fogging ability may be reduced.

[0081] That is, since the polyester resin composition according to one embodiment of the present invention contains more than 56% by weight of polyester resin, preferably polybutylene terephthalate resin; and less than 12% by weight of non-grafted copolymer, which is polymerized from components having a specific content range, large-area automotive interior parts manufactured using this composite resin composition can have anti-warping deformation capability and high-temperature anti-fogging capability, and can achieve a balance between impact, heat resistance and rigidity.

[0082] As a specific example, based on a total of 100% by weight of polyester resin composition, the non-graft copolymer may be included in an amount of 1% by weight to 12% by weight; or when the polyester resin composition includes antioxidants and lubricants, based on a total of 100% by weight of polyester resin, non-graft copolymer, fiber reinforcing agent, antioxidant and lubricant, the non-graft copolymer may be included in an amount of 1% by weight to 12% by weight.

[0083] Preferably, the ungrafted copolymer may be included in an amount of 3% to 11% by weight based on a total of 100% by weight of the polyester resin composition; or when the polyester resin composition includes antioxidants and lubricants, the ungrafted copolymer may be included in an amount of 3% to 11% by weight based on a total of 100% by weight of the polyester resin, the ungrafted copolymer, the fiber reinforcing agent, the antioxidant, and the lubricant.

[0084] Fiber reinforcing agent For example, the fiber reinforcing agent according to the present invention can be glass fiber.

[0085] Glass fibers may contain SiO2, CaO, and Al2O3. In this case, the amount of SiO2 may be greater than the total amount of CaO and Al2O3. Preferably, glass fibers in which the amount of SiO2 is greater than the total amount of CaO and Al2O3 can be used.

[0086] Glass fiber can improve mechanical properties by enhancing the rigidity of molded articles made using the polyester resin composition of the present invention.

[0087] For example, the glass fiber may contain 50% to 55% by weight of silica, specifically 50% to 55% by weight of silica, 10% to 23% by weight of alumina, and 13% to 26% by weight of calcium oxide; more preferably 50% to 55% by weight of silica, 10% to 16% by weight of alumina, and 13% to 23% by weight of calcium oxide; and even more preferably 53% to 55% by weight of silica, 12% to 16% by weight of alumina, and 19% to 23% by weight of calcium oxide. When glass fiber with a content within this range is used, a polyester resin composition with an excellent balance of physical properties between processing performance, specific gravity, and mechanical properties can be obtained, and this polyester resin composition can be used to manufacture molded articles with high heat resistance and rigidity.

[0088] In this disclosure, the content of silica can be measured or confirmed by X-ray fluorescence spectrometry (XRF).

[0089] Glass fibers can have either a circular cross-section or a flat cross-section. When glass fibers have a cross-section within this range, high rigidity, reduced weight, and excellent appearance can be ensured.

[0090] For example, glass fibers can have an aspect ratio of 1:1 to 1:4, specifically 1:1 to 1:3, and more specifically, 1:1. Here, the aspect ratio is expressed as the ratio of length (L) to diameter (D) (L / D). Within this range, high strength can be provided, and the surface appearance can be improved. As a more preferred example, the aspect ratio is 1:3 to 1:4, and as the most preferred example, 1:4. In this case, in addition to high rigidity, products with advantages in flatness, deformation, and orientation can also be provided.

[0091] In this disclosure, a scanning electron microscope (SEM) can be used to measure the diameter and length. Specifically, 20 inorganic fillers are selected using a scanning electron microscope, and the diameter and length of each inorganic filler are measured using an icon bar that can measure the diameter. The average diameter and average length are then calculated.

[0092] For example, the average diameter can be from 1 μm to 13 μm, specifically 5 μm to 10 μm, and the average length can be from 2.5 mm to 6 mm, specifically 3 mm to 4 mm. Within this range, processing performance can be improved, thereby improving the tensile strength of the molded articles manufactured by molding the polyester resin composition of the present invention.

[0093] The cross-section of glass fiber can be rectangular, elliptical, dumbbell-shaped, or rhomboid.

[0094] In one embodiment of the invention, glass fiber may be used in combination with other inorganic fibers, and the inorganic fibers may include one or more selected from carbon fiber, basalt fiber and natural fibers such as kenaf and hemp.

[0095] In one embodiment of the invention, glass fibers can be treated with sizing agents such as lubricants, coupling agents, and surfactants during fiber manufacturing or post-treatment. Within the scope of this invention, lubricants, coupling agents, and surfactants commonly used as sizing agents in the technical field to which this invention pertains can be used in this invention without particular limitation.

[0096] Lubricants are primarily used to form good strands during the manufacture of glass fibers, while coupling agents play a role in achieving good adhesion between the glass fibers and the base resin. When the types of base resin and glass fibers are appropriately selected, excellent physical properties can be imparted to the thermoplastic resin composition.

[0097] Sizing agents, especially coupling agents, can be applied directly to glass fibers or added to organic matrices. The appropriate concentration of the sizing agent can be selected to fully utilize its performance.

[0098] Examples of coupling agents include amine coupling agents, acrylic coupling agents and silane coupling agents, with silane coupling agents being preferred.

[0099] As a specific example, silane coupling agents may include one or more selected from γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β-(3,4-epoxyethyl)γ-aminopropyltrimethoxysilane.

[0100] Based on a total of 100% by weight of polyester resin composition, the fiber reinforcing agent may be included in amounts ranging from 10% to 38% by weight, 15% to 38% by weight, 15% to 35% by weight, 20% to 40% by weight, or 25% to 35% by weight; or based on a total of 100% by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the fiber reinforcing agent may be included in amounts ranging from 10% to 38% by weight, 15% to 38% by weight, 15% to 35% by weight, 20% to 40% by weight, or 25% to 35% by weight. When the content is less than this range, cracks may occur in molded articles made using polyester resin compositions containing fiber reinforcing agents. When the content exceeds this range, the dimensional stability of molded articles made using polyester resin compositions containing fiber reinforcing agents may be reduced, or the appearance may be poor.

[0101] Polyester resin composition The polyester resin composition according to one embodiment of the present invention is a composite material for providing improved thermal stability and mechanical properties, and may contain suitable additives.

[0102] For example, additives may include antioxidants, lubricants, and / or colorants.

[0103] Antioxidants can be selected from phenolic antioxidants and phosphite antioxidants.

[0104] Phenolic antioxidants and phosphite antioxidants can enhance thermal stability and are not particularly limited in type, as long as they can prevent high-temperature-induced degradation of the polyester resin composition or molding article. By including phenolic antioxidants as an essential component, the thermal stability of the polymer can be further improved by removing free radicals generated in the polyester resin composition during molding.

[0105] Phenolic antioxidants may preferably include hindered phenolic antioxidants having a crystallization temperature (Tm) of 110°C to 130°C.

[0106] As specific examples, phenolic antioxidants may include tetra[ethylene-3-(3,5-di-tert-butyl-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or mixtures thereof.

[0107] For example, phosphite antioxidants (high phenolic antioxidants) may include phosphite antioxidants having a melting temperature (Tm) of 180°C to 240°C. As specific examples, phosphite antioxidants may include tris(2,4-di-tert-butylphenyl) phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosspiro[5.5]undecane, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, or mixtures thereof.

[0108] For example, based on a total of 100% by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the antioxidant may be included in amounts from 0.1% to 10% by weight, 0.1% to 5% by weight, 0.1% to 3% by weight, 0.1% to 2% by weight, 0.1% to 1% by weight, or 0.1% to 0.5% by weight. Within this range, appearance defects such as stains can be prevented from occurring on the surface of the manufactured molded article, resulting in an excellent appearance.

[0109] For example, the lubricant can be a fatty acid and is used to help the polyester resin composition maintain excellent release and injection properties.

[0110] Lubricants can be used in this invention without particular limitations, as long as the lubricant can ensure the ease of injection and flowability of the injection screw used to manufacture molded articles using a polyester resin composition containing the lubricant.

[0111] The lubricant preferably includes stearate lubricants, and more preferably pentaerythritol tetrastearate, etc.

[0112] For example, based on a total of 100% by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the lubricant may be included in amounts from 0.1% to 10% by weight, 0.1% to 5% by weight, 0.1% to 3% by weight, 0.1% to 2% by weight, 0.1% to 1% by weight, or 0.1% to 0.5% by weight. Within this range, the polyester resin composition can be endowed with excellent peel and injection properties.

[0113] Various known colorants can be used as colorants, as long as they do not adversely affect the polyester resin composition of the present invention. Carbon black can be used as a representative example.

[0114] For example, based on a total of 100 parts by weight of polyester resin, ungrafted copolymer, fiber reinforcing agent, antioxidant, and lubricant, the polyester resin composition may contain 0.1 to 10 parts by weight, 0.1 to 5 parts by weight, 0.1 to 3 parts by weight, 0.1 to 2 parts by weight, or 0.1 to 1 part by weight of colorant. Within this range, excellent colorability can be provided to the polyester resin composition.

[0115] In one embodiment of the invention, the colorant may also be used in masterbatch form to improve commercialization.

[0116] The polyester resin composition can preferably be provided as a polyester resin composition for use in automotive interior parts such as large-area thin dashboards and navigation systems larger than 12 inches.

[0117] Method for preparing polyester resin compositions The method for preparing the polyester resin composition of the present invention will be described below. When describing the method for preparing the polyester resin composition, all of the above-described polyester resin compositions are included.

[0118] For example, a method for preparing the polyester resin composition of the present invention includes feeding polyester resin, ungrafted copolymer and fiber reinforcing agent into an extruder and performing melt kneading and extrusion.

[0119] For example, a method for preparing a polyester resin composition may include the above-mentioned additives.

[0120] For example, one or more selected from single-screw extruders, twin-screw extruders, and Banbury mixers, preferably twin-screw extruders, can be used for the melt kneading and extrusion steps. In this case, deterioration of mechanical properties and thermal stability can be prevented, and polyester resin compositions with excellent high-temperature anti-fogging capabilities can be provided.

[0121] The polyester resin composition according to the invention can be prepared by methods known in the art. For example, the polyester resin composition can be prepared in the form of an extruder by melting and extruding a mixture of components and additives in an extruder, and the extruder can be used to manufacture injection molded articles and extruded articles.

[0122] In one embodiment of the invention, extrusion is performed at a temperature of 250°C to 280°C or 260°C to 270°C. Here, temperature refers to the temperature set in the cylinder.

[0123] As a specific example, according to one embodiment of the present invention, the steps of melt kneading and extrusion may be the steps of feeding 59.5% to 69.5% by weight of polybutylene terephthalate with an intrinsic viscosity of 0.7 dl / g to 0.9 dl / g; 5% to 10% by weight of ungrafted copolymer; 20% to 40% by weight of fiber reinforcement; and 0.1% to 10% by weight of other additives into an extruder and performing melt kneading and extrusion.

[0124] In this disclosure, various conditions used in the technical field to which this invention pertains can be used as undefined melt kneading and extrusion conditions. For ease of injection molding, the extrudate can be formed, for example, in granule or chip form.

[0125] Furthermore, molding articles comprising the polyester resin compositions of the present invention will be described. When describing molding articles comprising the polyester resin compositions of the present invention, all of the above-described polyester resin compositions and methods thereof are included.

[0126] Molded products Using the polyester resin composition of the present invention, molded articles requiring mechanical properties and thermal stability can be manufactured.

[0127] For example, molded parts can be automotive interior components, such as large-area thin dashboards and navigation systems, which require low deformation thermal stability and high-temperature anti-fogging capabilities, or housings for automotive interior components.

[0128] The molded articles of the present invention can be manufactured using methods commonly used in the art. For example, the molded articles can be manufactured using injection molding, injection compression molding, extrusion molding (sheet casting), compression molding, pressure molding, hot bending, compression molding, calendering, or rotational molding.

[0129] For example, a method for manufacturing a molded article may include feeding polyester resin, ungrafted copolymer and additives into the main inlet of a twin-screw extruder (φ40, L / D: 42, SM Platek equipment) set at 260°C, 200 rpm and a flow rate (F / R) of 35 kg / h, and feeding fiber reinforcement into the side inlet at a flow rate of 15 kg / h, performing melt kneading and extrusion to obtain an extrudate, and placing the extrudate in an injection molding machine to manufacture a molded article.

[0130] To verify the performance of the polyester resin composition of the present invention, the extrudate can be dried at 100°C for more than 4 hours and then injected using an 80-ton injection molding machine (Engel, Victory 80).

[0131] During injection molding, the mold temperature is preferably between 40°C and 120°C. When the mold temperature is below 40°C, the appearance characteristics may deteriorate. When the mold temperature is above 120°C, the cooling time may become longer, which may reduce productivity. Specifically, the mold temperature can be between 60°C and 88°C, 70°C and 80°C, or 72°C and 78°C. Within this range, the appearance characteristics of the injection-molded articles can be improved, and the defect rate can be minimized due to the improved injection characteristics.

[0132] For example, an injection molding machine with the hopper temperature or nozzle temperature set to 240°C to 260°C can be used for the injection process.

[0133] According to one embodiment of the invention, during the injection molding process of the injection-molded article, the injection speed of the melt comprising the polyester resin composition can be from 30 mm / s to 80 mm / s. Specifically, the injection speed of the melt comprising the polyester resin composition during the injection molding of the injection-molded article can be from 35 mm / s to 75 mm / s, 45 mm / s to 65 mm / s, or 50 mm / s to 60 mm / s. Within this range, injection-molded articles of excellent quality can be manufactured by minimizing injection deviations at all points of the injection-molded article.

[0134] For example, the polyester resin composition may have a melt flow index of 12.8 g / 10 min or more, 12.9 g / 10 min or more, or 12.9 g / 10 min to 20 g / 10 min as measured according to ISO 1133, and may have a melt flow index of 1.47 g / cm³ as measured according to ISO 1183. 3 Above, 1.48 g / cm 3 Above, or 1.48 g / cm 3 Up to 1.53 g / cm 3 The specific gravity is such that, under these conditions, excellent thermal stability can be provided.

[0135] In this disclosure, the melt flow index can be measured at 265°C under a load of 2.16 kg, and the specific gravity can be measured at 23°C.

[0136] Furthermore, for example, the polyester resin composition can have a high load heat deflection temperature of 190°C or higher, 200°C or higher, 200°C to 210°C, or 202°C to 205°C as measured according to ISO 75 100. In this case, excellent heat deflection temperature can be provided.

[0137] In this disclosure, the high-load heat distortion temperature can be measured under a high load of 1.80 MPa according to ISO 75.

[0138] Furthermore, for example, when flexural strength and flexural modulus are measured using a 4.0 mm specimen according to ISO 178, the polyester resin composition of the present invention can have a flexural strength of 180 MPa or more, 182 MPa or more, or 182 MPa to 200 MPa, and a flexural modulus of 8000 MPa or more, 8000 MPa to 9000 MPa, or 8400 MPa to 9000 MPa. In this case, excellent flexibility and processability can be provided.

[0139] In this disclosure, flexural strength and flexural modulus can be measured at a rate of 2 mm / min using SPAN 64 according to ISO 178.

[0140] Furthermore, the polyester resin composition of the present invention can have, for example, a strength of 8.0 kJ / cm² as measured according to ISO 179 / 1eA. 2 Above, 8.5 kJ / cm 2 Above, or 8.5 kJ / cm 2 Up to 10.5 kJ / cm 2 The Charpy impact strength. In this case, excellent impact resistance can be provided.

[0141] In this disclosure, the Charpy impact strength can be measured using a notched specimen at 23°C.

[0142] Furthermore, when the MD direction length (in mm) and TD direction length (in mm) are measured by elevation testing, and the value (TD / MD) is obtained by dividing the TD direction length by the MD direction length, the polyester resin composition has a value (TD / MD) of 1.60 or less, 1.30 to 1.60, or 1.35 to 1.60. In this case, excellent shrinkage resistance can be provided.

[0143] Furthermore, when measuring the lift distance from the floor to the four corners using a square specimen with dimensions of 100mm × 100mm × 1.56mm according to the low-strain evaluation method, the polyester resin composition can have a maximum lift height of less than 5.0mm, 1.0 to 5.0mm, 1.5 to 4.5mm, and 1.5 to 4.0mm. In this case, warping deformation can be adequately prevented to provide low deformation.

[0144] In addition, the polyester resin composition can have a haze of less than 10.0, less than 5.0, 1.0 to 9.0, or 2.0 to 8.0 as measured by a haze test (150°C, 5 hours). In this case, fogging can be prevented even at high temperatures.

[0145] Specifically, the molded article can be a large-area, thin-walled automotive interior component or its housing. In particular, the molded article can be a large-screen thin-film head-up display (HUD) requiring both mechanical properties and thermal stability, but is not limited to any particular product.

[0146] In molded articles manufactured using a polyester resin composition according to one embodiment of the present invention, the material used is changed from conventional materials to a predetermined composite composition. Therefore, fogging can be prevented at high temperatures, and fogging can be improved. Furthermore, the balance of physical properties between mechanical properties, flowability, and thermal stability can be excellent, and product reliability and appearance can be improved.

[0147] In describing the polyester resin composition of the present invention, the method for preparing the polyester resin composition, and the molding article comprising the polyester resin composition, it should be noted that other conditions or equipment not explicitly described in this specification may be suitably selected within the scope commonly practiced in the art, without particular limitation.

[0148] Embodiments of the present invention will be described in detail below to enable those skilled in the art to readily implement the invention. However, the invention can be implemented in various different forms and is not limited to these embodiments.

[0149] [Example] The specifications for each component used in the examples are as follows. Here, % refers to weight%.

[0150] (A) Polybutylene terephthalate resin (weight average molecular weight: 75,000 g / mol, intrinsic viscosity: (IV) 0.8 dl / g) (B1) SAN resin (styrene: 72 wt%, acrylonitrile: 28 wt%, 92RF (LG Chemical Co., Ltd.), initiator-polymerized and degassed twice) (B2) SAN resin (styrene: 72 wt%, acrylonitrile: 28 wt%, 92 HRC (LG Chemical Co., Ltd.), initiator-polymerized and degassed once) (B3) SAN resin (styrene: 76 wt%, acrylonitrile: 24 wt%, 80HF (LG Chemical Co., Ltd.), thermopolymerized and degassed twice) (B4) ASA resin (acrylate: 45 wt%, styrene: 41 wt%, acrylonitrile: 14 wt%, SA927 (LG Chemical Co., Ltd.)) (C-1) Flat glass fiber with a cross-sectional dimension of 7μm×28μm, a length of 3mm and an aspect ratio of 1:4 (silicon dioxide: 54 wt%, aluminum oxide: 14 wt%, calcium oxide: 22 wt%) (C-2) Flat glass fiber with a cross-sectional dimension of 10μm×20μm, a length of 3mm and an aspect ratio of 1:2 (silicon dioxide: 54 wt%, aluminum oxide: 14 wt%, calcium oxide: 22 wt%) (C-3) Cylindrical glass fiber with a diameter of 10 μm and a length of 3 mm (silicon dioxide: 54 wt%, aluminum oxide: 14 wt%, calcium oxide: 22 wt%) (D) Hindered phenolic antioxidant: BASF Co., IRGANOX B-225 (IR-1010:IR-168 = 50:50 by weight) (E) Pentaerythritol tetrastearate lubricant: FACI ASIA PACIFIC PTE LTD Co. (Product name: PETS-AHS) (F) Colorant: Masterbatch obtained by mixing 20% ​​by weight of carbon black and 80% by weight of polybutylene terephthalate resin Table 1 shows the manufacturing methods, number of degassing treatments, physical properties, and gas quality of each of the ungrafted copolymers (B1) to (B3).

[0151] [Table 1] As shown in Table 1, the physical properties of ungrafted copolymers, such as melt flow index, heat distortion temperature and color index, as well as gas mass, such as total organic compound content, vary depending on the polymerization method and the number of degassing treatments.

[0152] Examples 1 to 4 and Comparative Example 1 The raw materials for the polyester resin compositions shown in Table 2 below are mixed and extruded to obtain a uniformly dispersed extruded polyester resin composition. Then, an injection molding process is performed. Specifically, heat is applied to the extruded material, and the extruded material is injected into a mold frame, then cooled to obtain a sample.

[0153] Specifically, each component was added according to the amounts shown in Table 2, and the mixture was melt-kneaded using a twin-screw extruder with L / D=42 and Φ=40mm in a temperature range of 250°C to 270°C to obtain a resin composition in extrusion form.

[0154] After drying the extrudate at 100°C for more than 4 hours, the dried extrudate was injected into an 80-ton injection molding machine (Victory 80, Engel Co.) at an injection temperature of 250°C to 260°C, a mold temperature of 70°C, and an injection speed of 40 mm / s to prepare specimens for evaluating mechanical properties.

[0155] The specimens required for each measurement method were prepared, and the performance of the specimens was measured using the methods described below. The results are shown in Table 2 below.

[0156] [Table 2] (In Table 2, A to E correspond to 100% by weight of the total weight, and F corresponds to 100 parts by weight of A to E.) Test Example 1: Evaluation of the physical properties of molded specimens The physical properties of the molded specimens prepared in Examples 1 to 4 and Comparative Example 1 were measured according to the following method.

[0157] - Specific gravity: Measured according to ISO 1183 (23°C) - Flowability (melt flow rate): Measured according to ISO 1133 (265°C, 2.16 kg). - Bending strength and flexural modulus: measured according to ISO 178 (4.0 mm, SPAN 64, speed: 2 mm / min, 23°C). -Charpy impact strength (IZOD): Measured according to ISO 179 / 1eA (notched, 23°C) - Heat distortion temperature: Measured according to ISO 75 (high load: 1.80 MPa) - Thermal stability: Measured according to UL94 V- test (V-0@0.8T) -TD / MD: A shrinkage specimen with dimensions of 60mm×60mm×2mm was manufactured according to the low strain assessment method. Its MD direction length (unit: mm) and TD direction length (unit: mm) were measured, and the value (TD / MD) was calculated by dividing the TD direction length by the MD direction length.

[0158] - Bending Evaluation: According to the lifting test, square specimens measuring 100mm × 100mm × 1.5mm were stored in a constant temperature / humidity chamber at 23℃ / 50%RH for 24 hours. Then, the square specimens were placed on a flat floor surface with one edge pressed against it. The lifting distance between the opposite edge and the floor surface was measured, and the maximum height was recorded. The average of the measurements from three specimens was taken as the representative value (maximum lifting height).

[0159] - Haze: Based on the haze test, prepare a square sample with dimensions of 100mm × 100mm × 1.5mm. Cut the sample into 10g slices. The haze is referenced below. Figure 1 The apparatus and process described in the figure are used for measurement.

[0160] Specifically, before placing the 10g sample into the test tube, check for any residual material in the test tube and wipe the inside of the test tube and the transparent glass plate three times with a 70% ethanol solution. Since ethanol may remain in the test tube, dry the test tube with a hair dryer before use.

[0161] Before measurement, the test sample is dried at 120°C for 2 to 4 hours, and then stored in a constant temperature / humidity chamber at 23°C / 50%RH for more than 24 hours before use.

[0162] Once the test tube and transparent glass plate are prepared, place 10g of the sample in the test tube and seal the opening with the transparent glass plate. Set the measurement temperature (150℃) and cooling temperature (23℃), and immerse the sample in the following conditions. Figure 1 The glass plate was placed in the device for 5 hours, and then the haze value was measured with a haze meter.

[0163] When measuring haze, the haze value is measured in three parts: the central portion of the glass plate, and the left and right portions based on the center. The average of these three measurements is recorded as the haze value of the sample. Here, as the haze value decreases, the occurrence of fogging decreases.

[0164] The results measured using the evaluation criteria are shown in Table 3 below.

[0165] [Table 3] As shown in Table 3, the polyester resin compositions of Examples 1 to 4 according to the present invention exhibit low tangential strength to maximum (TD / MD), low warpage, and low haze. Therefore, molded articles made using the polyester resin compositions meet mechanical properties such as impact strength and flexural strength, exhibit excellent thermal stability and flowability, and provide excellent product reliability and appearance due to improved high-temperature anti-fogging capabilities.

[0166] On the other hand, in Comparative Example 1, which does not contain non-grafted copolymers, the high-temperature anti-fogging ability and performance improvement are worse compared to Examples 1 to 4.

[0167] Additional Comparative Example 1 Except that the same amount of (B-2) was used instead of (B-1), the same steps as in Example 1 were repeated. The performance of the molded specimens manufactured in Additional Comparative Example 1 was evaluated in the same manner as in Test Example 1, and the results are shown in Table 4 below.

[0168] Additional Comparative Example 2 Except that the same amount of (B-3) was used instead of (B-1), the same steps as in Example 1 were repeated. The performance of the molded specimens manufactured in Additional Comparative Example 2 was evaluated in the same manner as in Test Example 1, and the results are shown in Table 4 below.

[0169] Additional Comparative Example 3 Except that (B-1) was used in an amount of 15% by weight, the same steps as in Example 1 were repeated. The performance of the molded specimens manufactured in Additional Comparative Example 3 was evaluated in the same manner as in Test Example 1, and the results are shown in Table 4 below.

[0170] Additional Comparative Example 4 Except that the amount of (B-1) was 7.5% by weight and the amount of (B-4) corresponding to the graft copolymer was 7.5% by weight, the same steps as in Example 1 were repeated. The performance of the molded specimens manufactured in Additional Comparative Example 4 was evaluated in the same manner as in Test Example 1, and the results are shown in Table 4 below.

[0171] [Table 4] As shown in Table 4, in the cases of Additional Comparative Examples 1 and 2, even when a non-grafted copolymer composed of aromatic vinyl compounds and vinyl cyanide compounds was included, a proper recycling operation was not performed, resulting in insufficient heat distortion temperature, melt index, physical properties, and gas mass. Therefore, compared to Example 1, Additional Comparative Examples 1 and 2 exhibited poorer high-temperature anti-fogging capabilities.

[0172] Furthermore, in the case of Additional Comparative Example 3 containing an excessive amount of ungrafted copolymer, the high-temperature anti-fogging capability deteriorated compared to Example 1.

[0173] Furthermore, in Comparative Example 4, which does not contain non-grafted copolymers, the bending strength and bending modulus are also worse than in Example 1, except for the high-temperature anti-fogging ability.

[0174] That is, the molded articles made using the polyester resin composition according to one embodiment of the present invention achieve a balance of physical properties between mechanical properties, flowability and thermal stability by using low-strain materials as raw materials, and have excellent product reliability and appearance by preventing fogging even at high temperatures.

Claims

1. A polyester resin composition comprising a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound and a vinyl cyanide compound; and a fiber reinforcing agent. in, When the MD direction length (in mm) and TD direction length (in mm) are measured by lifting tests, and the value (TD / MD) is obtained by dividing the TD direction length by the MD direction length, the polyester resin composition has a value (TD / MD) of 1.60 or less. The polyester resin composition has a haze of less than 10.0 as measured by a fogging test (150°C, 5 hours).

2. The polyester resin composition according to claim 1, wherein, The polyester resin is a polyalkylene terephthalate resin.

3. The polyester resin composition according to claim 1, wherein, The polyester resin has an intrinsic viscosity (η) of 0.7 dl / g to 0.9 dl / g.

4. The polyester resin composition according to claim 1, wherein, Based on a total of 100% by weight of the polyester resin composition, the polyester resin is contained in an amount of 56% by weight or more.

5. The polyester resin composition according to claim 1, wherein, The ungrafted copolymer contains more than 20% by weight of a vinyl cyanide compound, has a heat distortion temperature of more than 96.5°C as measured in ASTM D648 at 18.6 kgf, and has a melt index of 28 to 32 (220°C, 10 kgf) as measured in ASTM D1238.

6. The polyester resin composition according to claim 1, wherein, The ungrafted copolymer is included in an amount of less than 12% by weight, based on a total of 100% by weight of the polyester resin composition.

7. The polyester resin composition according to claim 1, wherein, The fiber reinforcing agent is glass fiber.

8. The polyester resin composition according to claim 7, wherein, The glass fiber contains SiO2, CaO and Al2O3, and the SiO2 content is greater than the sum of the CaO and Al2O3 contents.

9. The polyester resin composition according to claim 1, wherein, The glass fiber contains 50% to 55% by weight of SiO2 and 15% to 21% by weight of Al2O3. 3、 And 13% to 19% by weight of CaO.

10. The polyester resin composition according to claim 1, wherein, The fiber reinforcing agent is contained in an amount of 20% to 40% by weight, based on a total of 100% by weight of the polyester resin composition.

11. The polyester resin composition according to claim 1, wherein, The polyester resin composition comprises an antioxidant and a lubricant, and the antioxidant and the lubricant are each contained in an amount of 0.1% to 10% by weight based on a total of 100% by weight of the polyester resin, the ungrafted copolymer, the fiber reinforcing agent, the antioxidant, and the lubricant.

12. The polyester resin composition according to claim 1, wherein, Based on a total of 100 parts by weight of the polyester resin, the ungrafted copolymer, the fiber reinforcing agent, the antioxidant, and the lubricant, the polyester resin composition comprises 0.1 to 10 parts by weight of a colorant.

13. The polyester resin composition according to claim 1, wherein, The polyester resin composition has a high load heat distortion temperature of over 190°C measured at 1.82 MPa according to ISO 100 75, and a flexural strength of over 180 MPa and a flexural modulus of over 8000 MPa measured according to ISO 178 using a 4.0 mm specimen and SPAN 64 at a rate of 2 mm / min.

14. The polyester resin composition according to claim 1, wherein, When the lifting distance from the floor to the four corners is measured using a square specimen with dimensions of 100mm × 100mm × 1.56mm according to the low strain evaluation method, the polyester resin composition has a maximum lifting height of less than 5.0mm.

15. A method for preparing a polyester resin composition, comprising kneading and extruding a polyester resin; a non-grafted copolymer composed of an aromatic vinyl compound and a vinyl cyanide compound; and a fiber reinforcing agent. in, When the MD direction length (in mm) and TD direction length (in mm) are measured using a shrinkage sample (size: 60 mm × 60 mm × 2 mm), and the value (TD / MD) is calculated by dividing the TD direction length (in mm) by the MD direction length (in mm), the polyester resin composition has a value (TD / MD) of 1.60 or less, and the polyester resin composition has a haze of 10.0 or less as measured by a haze test (150 °C, 5 hours).

16. A molding article comprising a polyester resin composition according to any one of claims 1 to 14.

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