Polyester resin composition, its manufacturing method and molded article manufactured therefrom

Abstract

The present invention relates to a polyester resin composition, a manufacturing method thereof, and a molded article manufactured therefrom. According to the present invention, by maintaining a balance between mechanical properties and heat resistance, flatness can be maintained even in a high temperature environment, minimizing deformation. In particular, the present invention has an effect of providing a polyester resin composition suitable as a material for automobile parts including electronic control unit parts, covers thereof or cover parts thereof, a manufacturing method thereof, and a molded article manufactured therefrom.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0011940 filed on January 27, 2022 and Korean Patent Application No. 10-2023-0001101 refiled on January 4, 2023 based thereon, and all contents disclosed in the documents of the Korean patent application are incorporated as part of this specification.

[0002] The present invention relates to a polyester resin composition, a manufacturing method thereof, and a molded article manufactured therefrom. More specifically, the present invention relates to a polyester resin composition that maintains a balance between mechanical properties and heat resistance, minimizes deformation even in high-temperature environments, and maintains flatness, and is therefore particularly suitable for automotive parts integrated with complex structures, and a molded article containing the same. [Background technology]

[0003] Polybutylene terephthalate resin (hereinafter referred to as "PBT" resin) and polyethylene terephthalate resin (hereinafter referred to as "PET" resin), which fall under the category of polyester resin, have excellent mechanical and electrical properties as well as other physical and chemical characteristics, and are therefore used in a wide range of fields, including automobiles, electrical and electronic devices, and office equipment.

[0004] In particular, PBT and PET are being actively used in automobile parts, where the number of parts is increasing and various parts are becoming more integrated due to the recent development of electric vehicles and autonomous driving technology.

[0005] However, in the case of automotive parts, when a car is exposed to the outdoors in summer and heats up to 80°C or more, severe warping is observed, or even if it is not serious, the problem of not being able to maintain the flatness at the time of delivery remains unresolved.

[0006] Therefore, there is a need for technological development of polyester resin compositions that are excellent in low warpage properties and are suitable for automobile parts integrated with complex structures, and automobile housing parts including molded articles thereof. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 10-2017-0080859 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a polyester resin composition that maintains a balance between mechanical properties and heat resistance, minimizes deformation even in high temperature environments, and maintains flatness, making it particularly suitable for automotive parts that are integrated with complex structures.

[0009] Another object of the present invention is to provide a method for producing the polyester resin composition.

[0010] Another object of the present invention is to provide a molded article produced from the polyester resin composition. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides 28 to 50% by weight of polybutylene terephthalate resin; 20 to 40% by weight of polyethylene terephthalate resin, 20.5 to 30% by weight of reinforcing fiber; and 5 to 30% by weight of layered clay minerals; The polyethylene terephthalate resin provides a polyester resin composition comprising one or more units selected from the group consisting of 1,4-cyclohexanedimethanol, isophthalic acid, and butanediol.

[0012] The polyethylene terephthalate resin (PET) and the layered clay mineral may be contained in a weight ratio (PET:layered clay mineral) of 1:0.9 to 1.8.

[0013] The polybutylene terephthalate resin (PBT) and the polyethylene terephthalate resin (PET) may be contained in a weight ratio (PBT:PET) of 1:0.3 to 1.5.

[0014] The polybutylene terephthalate resin may have a weight average molecular weight (Mw) of 20,000 to 100,000 g / mol and a melting point of 200 to 240° C. as measured by DSC.

[0015] The polyethylene terephthalate resin may have a melting point of 200 to 270° C. as measured by DSC.

[0016] The reinforcing fibers and the layered clay mineral may be contained in a weight ratio of 1:0.1 to 0.3 (reinforcing fibers:layered clay mineral).

[0017] The reinforcing fibers may be glass fibers.

[0018] The glass fiber may contain 20 to 65 weight % of silica; 1 to 40 weight % of aluminum oxide; 10 to 60 weight % of calcium oxide; and 5 weight % or less of one or more selected from iron oxide, magnesia, sodium oxide, iron, and boron oxide, and may have a diameter of 7 to 15 μm and a length of 3 to 6 mm.

[0019] The layered clay mineral may be at least one selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite.

[0020] The polyester resin composition may contain one or more additives selected from a heat stabilizer, a UV stabilizer, a lubricant, a plasticizer, a flame retardant, a flame retardant auxiliary, a colorant, a release agent, a pigment, a dye, an ester exchange reaction inhibitor, an antistatic agent, an antibacterial agent, a processing aid, a metal deactivator, a fluorine-based drip prevention agent, and a colored masterbatch.

[0021] The additives may be contained in an amount of 0.1 to 5% by weight based on 100% by weight of all components constituting the polyester resin composition (polybutylene terephthalate resin + polyethylene terephthalate resin + reinforcing fiber + layered clay mineral + additives).

[0022] The polyester resin composition may be such that a test piece having a width x length of 200 mm x length of 100 mm and a thickness of 2T has a difference in height in the height direction of 0.25 mm or less before and after being left at a temperature of 100°C for 30 minutes.

[0023] The polyester resin composition may have a flexural modulus, measured according to ISO 178, of 8120 MPa or more.

[0024] The polyester resin composition may have a heat distortion temperature (HDT) of 190° C. or higher, measured under conditions of ISO 75-1 / 2 and 1.80 MPa.

[0025] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: The method includes a step of kneading and extruding 28 to 50% by weight of polybutylene terephthalate resin, 20 to 40% by weight of polyethylene terephthalate resin, 20.5 to 30% by weight of reinforcing fiber, and 5 to 30% by weight of layered clay mineral, The polyethylene terephthalate resin includes at least one selected from the group consisting of 1,4-cyclohexanedimethanol, isophthalic acid, and butanediol.

[0026] The layered clay mineral may be at least one selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite.

[0027] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A molded article is provided that includes the polyester resin composition described above.

[0028] The molded article may be a part, a cover or a cover part of an electronic control unit including an engine control unit, a transmission (TCU), an electronic stability control (ESC) system, an airbag control system, a tire pressure management (TPMS) system, and an occupant classification sensing system (PODS). Effect of the Invention

[0029] The polyester resin composition according to the present invention not only significantly improves the balance between mechanical strength and heat resistance by controlling the structure and content of the polyethylene terephthalate resin blended with the polybutylene terephthalate resin and adjusting the weight ratio of the glass fiber and the specific layered clay mineral, but also maintains flatness and minimizes deformation even in high temperature environments. As a result, the composition is particularly suitable for integrated automotive parts with complex structures and can reduce manufacturing costs.

[0030] Therefore, the polyester resin composition according to the present invention can be preferentially applied to electronic control unit (ECU) parts, covers thereof or cover parts thereof, including engine control units, transmissions (TCU), electronic stability control (ESC), airbag control, tire pressure management (TPMS), occupant classification sensing systems (PODS), etc., which require the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] In the following, the present invention will be described in more detail to facilitate understanding of the present invention.

[0032] The terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meaning, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, taking into consideration that the inventor can appropriately define the concept of the term in order to explain the invention in the best possible manner.

[0033] Throughout this specification, when a part "comprises" a certain element, this does not mean to exclude other elements, but means that it can further include other elements, unless specifically stated to the contrary.

[0034] The term "content" as used in this description has the unit of weight percent, unless otherwise specified.

[0035] The term "low warpage characteristics" used in this description refers to the fact that the height dimension of the same test piece is maintained after being left at high temperature for a certain period of time compared to the height dimension of the test piece immediately after production. The lower warpage characteristics are more preferable when the deviation of the height dimension is closer to 0, and it is also preferable that there is no variation in the average height dimension between test pieces.

[0036] In particular, the present inventors have confirmed that, as a material for electronic control unit parts, covers thereof or cover parts thereof, including automobile engine control units, transmissions (TCUs), electronic stability control (ESC), airbag control, tire pressure management (TPMS), occupant classification sensing systems (PODS), etc., when a specific component capable of minimizing deformation even under high temperature conditions is added to a base resin composed of polybutylene terephthalate resin and polyethylene terephthalate resin and the amount of use of the component is adjusted, the balance between mechanical strength and heat resistance is greatly improved, deformation is minimized even in high temperature environments, and flatness is maintained, making the material particularly suitable for integrated automobile parts with complex structures. Through further research, the present invention has been completed.

[0037] One embodiment of the present invention provides a polyester resin composition comprising polybutylene terephthalate resin, polyethylene terephthalate resin, reinforcing fibers, and a layered clay mineral.

[0038] The polyethylene terephthalate resin is characterized by containing at least one selected from the group consisting of 1,4-cyclohexanedimethanol, isophthalic acid, and butanediol.

[0039] The polyethylene terephthalate resin (PET) and the layered clay mineral are contained in a weight ratio (PET:layered clay mineral) of 1:0.9 to 1.8.

[0040] The layered clay mineral is at least one selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite.

[0041] The polyester resin composition according to the present invention can maintain flatness and minimize deformation even in a high temperature environment by controlling the structure of the polyethylene terephthalate resin blended with the polybutylene terephthalate resin and adjusting the weight ratio of the reinforcing fiber and the layered clay mineral.

[0042] Hereinafter, each component constituting the polyester resin composition of the present invention will be specifically described.

[0043] Polybutylene Terephthalate Resin According to an embodiment of the present invention, the polyester resin composition includes a polybutylene terephthalate resin. As described above, the polyester resin composition includes a polybutylene terephthalate resin, so that the polyester resin composition can achieve the physical properties required for automobile parts.

[0044] In one embodiment of the present invention, the polybutylene terephthalate resin may be a polybutylene terephthalate resin obtained by direct esterification or transesterification of 1,4-butanediol with terephthalic acid or dimethyl terephthalate to obtain a polybutylene terephthalate resin.

[0045] The polybutylene terephthalate resin (PBT) included as one type of base resin in the polyester resin composition of the present invention may have a repeating unit represented by the following chemical formula 1.

[0046] [ka]

[0047] In the above Chemical Formula 1, n represents an integer of 50 or more, for example, an integer of 50 to 200.

[0048] In one embodiment of the present invention, in order to increase the impact strength of the polyester resin composition, a copolymer obtained by copolymerizing the polybutylene terephthalate resin with an impact improving compound such as polytetramethylene glycol, polyethylene glycol, polypropylene glycol, aliphatic polyester, aliphatic polyamide, etc. as a comonomer, or a modified polybutylene terephthalate resin obtained by reacting the polybutylene terephthalate resin with the impact improving compound may be used.

[0049] In one embodiment of the present invention, the intrinsic viscosity η of the polybutylene terephthalate resin measured in accordance with ASTM D2857 is, for example, 0.6 dl / g to 1.8 dl / g, 0.7 dl / g to 1.3 dl / g, or 0.9 to 1.3 dl / g. When the intrinsic viscosity of the polybutylene terephthalate resin satisfies the above range, a polyester resin composition having an excellent balance of mechanical properties and processability can be obtained.

[0050] The intrinsic viscosity (η) can be measured by dissolving a sample to be measured in methylene chloride and then measuring the filtrate obtained by the dissolution at 20° C. using an Ubbelohde type viscometer.

[0051] The polybutylene terephthalate resin may have a weight average molecular weight of, for example, 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 70,000 g / mol. Within the above range, mechanical properties can be improved.

[0052] Specifically, the weight average molecular weight is measured by preparing a sample having a compound concentration of 1 wt% by putting tetrahydrofuran (THF) and the compound in a 1 ml glass bottle, filtering the standard sample (polystyrene) and the sample through a filter (pore size 0.45 μm), injecting the sample into a GPC injector, and comparing the elution time of the sample with the calibration curve of the standard sample to obtain the molecular weight and molecular weight distribution of the compound. In this case, an Infinity II 1260 (Agilient) can be used as a measuring device, and the flow rate can be set to 1.00 mL / min and the column temperature to 40.0° C.

[0053] The polybutylene terephthalate resin may have a melting point measured by DSC of, for example, 200 to 240° C. or 210 to 230° C. When the melting point satisfies the above range, the mechanical properties can be maintained even under high temperature conditions.

[0054] In one embodiment of the present invention, the polybutylene terephthalate resin may be contained in the base resin containing the polybutylene terephthalate resin and the polyethylene terephthalate resin in an amount of, for example, 28 to 50 wt%, 30 to 50 wt%, or 30 to 45 wt%. If the content is less than the above range, a problem of a slow solidification speed during injection molding and a long cycle time may occur, and if the content exceeds the above range, significant warpage may occur under high temperature conditions.

[0055] The method for producing the polybutylene terephthalate resin is not particularly limited as long as it is a polymerization method commonly used in the technical field to which the present invention belongs, and if it meets the definition of the polybutylene terephthalate resin according to the present invention, it may be commercially purchased and used.

[0056] Polyethylene terephthalate resin According to one embodiment of the present invention, the polyester resin composition includes a polyethylene terephthalate resin. As described above, the polyester resin composition includes a polyethylene terephthalate resin, so that the polyester resin composition can achieve the physical properties required for automobile parts and their cover parts.

[0057] According to an embodiment of the present invention, the polyethylene terephthalate resin is not particularly limited as long as it is a normal polyethylene terephthalate resin, and more specifically, it is preferably a copolyethylene terephthalate polymer.

[0058] The polyethylene terephthalate resin, which is yet another component of the polyester resin composition of the present invention, can have a repeating unit represented by the following chemical formula 2 as a basic structure.

[0059] [ka]

[0060] In the above Chemical Formula 2, m represents an integer of 1 or more, for example, an integer of 40 to 160.

[0061] In one embodiment of the present invention, in order to increase the impact strength of the polyester resin composition, a copolymer obtained by copolymerizing the polyethylene terephthalate resin with an impact improving compound such as polytetramethylene glycol, polyethylene glycol, polypropylene glycol, aliphatic polyester, aliphatic polyamide, etc. as a comonomer, or a modified polyethylene terephthalate resin obtained by reacting the polyethylene terephthalate resin with the impact improving compound may be used.

[0062] In this case, examples of the impact improving compound include 1,4-cyclohexanedimethanol, isophthalic acid, butanediol, and the like.

[0063] The impact improving compound may be included as a unit constituting the skeleton of the polyethylene terephthalate resin, and in this case, the amount added may be 5 to 45 mol %, or 10 to 40 mol %.

[0064] In one embodiment of the present invention, the intrinsic viscosity (IV, η) of the polyethylene terephthalate resin measured in accordance with ASTM D2857 is, for example, 0.5 to 1 dl / g, preferably 0.6 to 1.0 dl / g, taking into consideration the processability and mechanical properties of the polyethylene terephthalate resin. When the intrinsic viscosity of the polyethylene terephthalate resin satisfies the above range, a polyester resin composition that provides excellent low warpage properties can be obtained.

[0065] The polyethylene terephthalate resin may have a melting point measured by DSC of, for example, 200 to 270° C., or 230 to 250° C. When the melting point satisfies the above range, the mechanical properties can be maintained under high temperature conditions.

[0066] In one embodiment of the present invention, the polyethylene terephthalate resin may be included in an amount of 20 to 40 wt%, 20 to 35 wt%, or 23 to 35 wt%, based on the total weight of the polyester resin composition. By controlling the content of the polyethylene terephthalate resin within the above range, the mechanical properties of the polyester composition can be improved, and excellent low warpage properties can be provided.

[0067] The method for producing the polyethylene terephthalate resin is not particularly limited as long as it is a polymerization method commonly used in the technical field to which the present invention belongs, and if it meets the definition of the polyethylene terephthalate resin according to the present invention, it may be commercially purchased and used.

[0068] Reinforcing Fiber In one embodiment of the present invention, the polyester resin composition contains reinforcing fibers, which can improve the physical properties of a molded article of the polyester resin composition, specifically, the tensile strength and flexural strength of the molded article.

[0069] According to an embodiment of the present invention, the reinforcing fiber may be glass fiber, which may be used together with other inorganic fibers and / or natural fibers. The inorganic fibers may be, for example, carbon fibers, basalt fibers, etc., and the natural fibers may be kenaf or hemp, etc.

[0070] In one embodiment of the present invention, the cross section of the glass fiber may have a shape such as a circle, a rectangle, an ellipse, a dumbbell, or a diamond, and may have a diameter of, for example, 7 to 20 μm or 7 to 15 μm and a length of, for example, 2 to 6 mm or 3 to 6 mm. When the above-mentioned ranges are satisfied, an excellent balance of mechanical properties can be achieved. For example, the diameter and length may be an average diameter and an average length, respectively.

[0071] The diameter and length of the glass fiber can be measured by a method commonly used in this technical field, for example, by observing the glass fiber with a scanning electron microscope (SEM).

[0072] The average diameter and the average length of the glass fibers may be values ​​obtained by measuring 50 glass fibers and averaging the measured values.

[0073] The cross section of the glass fiber may have a shape such as a circle, a rectangle, an oval, a dumbbell, a diamond, etc.

[0074] The glass fibers may be treated with sizing compositions during the manufacture of the fibers or during a post-treatment step.

[0075] The sizing agent is mainly used for forming good strands, and the coupling agent enables good adhesion between the glass fiber and the polybutylene terephthalate resin or the polyethylene terephthalate resin. When appropriately selected in consideration of the types of the polybutylene terephthalate resin, the polyethylene terephthalate resin, and the glass fiber, the coupling agent can impart excellent physical properties to the polyester resin composition.

[0076] The sizing agent can be used in a variety of ways, including directly treating the glass fiber and adding the sizing agent to a polybutylene terephthalate resin or a polyethylene terephthalate resin. In order to fully exert the performance of the sizing agent, the content of the sizing agent must be appropriately selected.

[0077] Examples of the sizing agent include amine-based, acrylic-based, and silane-based sizing agents, and examples of the silane-based sizing agents include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)γ-aminopropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β(3,4-epoxyethyl)γ-aminopropyltrimethoxysilane.

[0078] In particular, the glass fibers described herein preferably contain silica, which provides stiffness and mechanical properties.

[0079] In this case, the silica may be contained in the glass fiber in an amount of, for example, 20 to 65% by weight, preferably 25 to 60% by weight, and more preferably 30 to 55% by weight. By adjusting the content of the glass fiber within the above-mentioned range, the impact resistance and mechanical properties of the polyester composition can be improved. If the content is less than the above range, the effect of adding the glass fiber on improving the heat resistance and mechanical properties may be small, and if the content exceeds the above range, the low warpage property may be significantly reduced.

[0080] Furthermore, aluminum oxide may be contained in the glass fibers in an amount of, for example, 1 to 40% by weight, or 5 to 30% by weight.

[0081] Furthermore, calcium oxide may be contained in the glass fibers in an amount of, for example, 10 to 60% by weight, or 20 to 50% by weight.

[0082] In addition, one or more selected from iron oxide, magnesia, sodium oxide, iron and boron oxide may be contained in an amount of 5% by weight or less, or 0.001 to 5% by weight.

[0083] In one embodiment of the present invention, the reinforcing fiber may be added in an amount greater than that of the polyethylene terephthalate resin, thereby further improving the reinforcing effect within the injection product.

[0084] Specifically, the reinforcing fiber may be included in an amount of 20.5 to 30 wt % or 23 to 28 wt % based on the total weight of the polyester resin composition. By adjusting the content of the reinforcing fiber within the above range, the tensile strength and flexural strength of a molded article manufactured from the polyester resin composition can be improved.

[0085] Layered clay minerals The layered clay mineral according to the present invention may include at least one selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorohectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite. When the layered clay mineral is used, it serves as a filler to reduce the aspect ratio due to the crystal structure of the polymer constituting the base resin and the reinforcing fibers, thereby imparting excellent low warpage properties.

[0086] The layered clay mineral may be included in an amount of 2 to 30 wt%, 5 to 15 wt%, or 5 to 10 wt%, based on the total weight of the polyester resin composition. When included in the above range, it is possible to prevent a decrease in physical properties such as mechanical strength due to the destruction of reinforcing fibers caused by the layered clay mineral, and to maintain excellent physical properties.

[0087] <Polyester resin composition> The polyester resin composition according to the present invention may contain polybutylene terephthalate resin and polyethylene terephthalate resin in a weight ratio (PBT:PET) of 1:0.9 to 1.8. When the above-mentioned range is satisfied, it is possible to improve low warpage characteristics while maintaining mechanical properties.

[0088] The polybutylene terephthalate resin and the polyethylene terephthalate resin may be included in a weight ratio (PBT:PET) of 1:0.9 to 1.6, or a weight ratio (PBT:PET) of 1:1 to 1.4, for example. When the above-mentioned range is satisfied, low warpage characteristics can be improved while maintaining mechanical properties. When the ratio is below the above-mentioned range, problems occur in which deformation including warpage occurs significantly under high temperature conditions, and when the ratio is above the above-mentioned range, problems occur in which the solidification speed is slow during injection molding, resulting in a long cycle time.

[0089] In the polyester resin composition according to the present invention, the reinforcing fiber can be added in an amount greater than that of the layered clay mineral, and in this case, the solidification speed can be increased and low warpage properties can be improved.

[0090] As an example, the weight of the reinforcing fiber may be such that the reinforcing fiber and the layered clay mineral are contained in a weight ratio of 1:0.1 to 0.3 (reinforcing fiber:layered clay mineral), or a weight ratio of 1:0.15 to 0.25 (reinforcing fiber:layered clay mineral).

[0091] The additives contained in the polyester resin composition according to the present invention may further include at least one selected from a heat stabilizer, a UV stabilizer, a lubricant, a plasticizer, a flame retardant, a flame retardant auxiliary, a colorant, a release agent, a pigment, a dye, an ester exchange reaction inhibitor, an antistatic agent, an antibacterial agent, a processing aid, a metal deactivator, a fluorine-based drip prevention agent, and a colored masterbatch.

[0092] In one embodiment of the present invention, the additive may be included in an amount of 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 1 wt% based on the total weight of the polyester resin composition. When included in the above range, the additive does not affect the physical properties of the resin composition and exhibits its inherent properties.

[0093] The heat stabilizer may be a phenol-based heat stabilizer, a hindered amine-based compound, etc. Specifically, the phenol-based heat stabilizer may be, for example, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

[0094] Specifically, the content of the heat stabilizer may be 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 1 wt% based on the total weight of the polyester resin composition. By controlling the content of the heat stabilizer within the above range, the polyester resin composition has excellent impact strength, and has excellent heat resistance properties by increasing the heat distortion temperature and reducing the flow index.

[0095] In the present invention, Hindered Phenolic Antioxidant 1010 can be used as the phenolic compound.

[0096] The hindered amine compound can impart hydrolysis resistance by reacting a hindered amine end group with an end group of a polymer constituting a base resin. Specifically, when the hindered amine compound is used, gas generation during molding of the polyester composition can be effectively suppressed.

[0097] The hindered amine compound may be, for example, a halogen-free alkoxy hindered amine having a weight average molecular weight of 2200 to 2300 g / mol.Specific examples include poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl]-[(2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piperidyl)imino] (CAS number 71878-19-8), etc.

[0098] The hindered amine compound may be included in an amount of 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 1 wt% based on the total weight of the polyester resin composition. By adjusting the content of the hindered amine compound within the above range, the physical properties can be achieved without compromising the hydrolysis resistance effect provided by the chain extender.

[0099] The lubricant may be an olefin wax, and serves to enable the polyester resin composition to maintain excellent mold releasability and injectability.

[0100] The olefin wax may be a polymer having a low melt viscosity and a solid oily phase having slipperiness and plasticity. For example, the wax may be one or more waxes selected from polyethylene wax and polypropylene wax. Commercially available products may also be used.

[0101] In one embodiment of the present invention, the lubricant may be included in an amount of 0.1 to 5 wt %, 0.1 to 3 wt %, or 0.1 to 1 wt % based on the total weight of the polyester resin composition. When the above range is satisfied, excellent mold releasability and injectability can be sufficiently provided.

[0102] The polyester resin composition may contain a plasticizer, such as glycerol, which facilitates chain folding during crystal formation, to control crystallization through an increase in the number of crystal nuclei.

[0103] The polyester resin composition may be preferably a polyester resin composition for cover parts of automobile parts, where the automobile parts include not only general parts but also electronic control unit (ECU) parts, covers thereof or cover parts thereof, including engine control units, transmissions (TCU), ESCs, airbag controls, tire pressure management systems (TPMS), occupant classification sensing systems (PODS), etc.

[0104] The polyester resin composition of the present invention may have a height difference in the height direction before and after a test piece having dimensions of 200 mm x 100 mm and a thickness of 2T is left at a temperature of 100°C for 30 minutes that is 0.25 mm or less, 0.01 to 0.25 mm, or 0.05 to 0.25 mm. When the above range is satisfied, deformation at high temperature conditions can be minimized at all points of the molded product, thereby improving low warpage properties. Here, 12 mm represents the height of the molded product, and 2T represents the thickness of the molded product.

[0105] The polyester resin composition may have a flexural modulus of, for example, 8120 MPa or more, specifically 8120 to 9000 MPa, and preferably 8130 to 8250 MPa, measured in accordance with ISO 178. When the flexural modulus is within the above range, low warpage characteristics can be provided under high temperature conditions while maintaining mechanical properties.

[0106] The polyester resin composition has a Charpy impact strength of, for example, 6.6 kJ / m as measured in accordance with ISO 179.2 The above is a specific example of 6.6 to 7.5 kJ / m 2 , and preferably 6.6 to 6.9 kJ / m 2 When the above range is satisfied, low warpage characteristics can be provided under high temperature conditions while maintaining mechanical properties.

[0107] The polyester resin composition may have a heat distortion temperature (HDT) measured under ISO 75-1 / 2 and a load condition of 1.80 MPa of, for example, 190° C. or more, specifically, 190 to 205° C., and preferably, 190 to 200° C. When the HDT satisfies the above range, low warpage characteristics can be provided under high temperature conditions while maintaining mechanical properties.

[0108] <Method of producing polyester resin composition> The polyester resin composition according to the present invention may be prepared by a method known in the art. For example, the polyester resin composition may be prepared in the form of pellets by melt-extruding a mixture of each component and other additives in an extruder, and the pellets may be used for injection and extrusion molding.

[0109] In one embodiment of the present invention, the pellets are injected or extruded at a temperature of 240 to 300°C or 250 to 290°C, and the temperature of the mold during injection molding is preferably in the range of 60 to 120°C. If the temperature of the mold is 60°C or lower, the appearance characteristics may be deteriorated, and if it is 120°C or higher, the resin composition may stick to the mold, resulting in a deteriorated mold release property and an increased cooling rate. The temperature of the mold may be specifically 60 to 100°C, 70 to 90°C, or 75 to 85°C. When the above range is satisfied, even if the temperature of the injection mold is adjusted during injection molding, deformation including warpage at all points of the injection molded product can be minimized, and low warpage characteristics can be improved.

[0110] According to one embodiment of the present invention, in the process of injection molding the injection molded product, the injection speed of the melt of the polyester resin composition may be 20 to 100 mm / s. Specifically, in the process of injection molding the injection molded product, the injection speed of the melt of the polyester composition may be 20 to 90 m / s, 20 to 80 mm / s, or 30 to 60 mm / s. When the above range is satisfied, even if the temperature of the injection mold is controlled during injection molding of the injection molded product, deformation including warpage at all points of the molded product can be minimized, thereby improving low warpage properties.

[0111] As an example, the method for producing a polyester resin composition of the present invention is characterized by including a step of kneading and extruding a polyester resin composition containing the above-mentioned polybutylene terephthalate resin, polyethylene terephthalate resin, reinforcing fiber, layered clay mineral, and other additives, and in this case, a balance of physical properties such as rigidity, processability, and low warpage characteristics can be achieved.

[0112] <Molded products> According to another embodiment of the present invention, there is provided a molded article made from the above-mentioned polyester resin composition.

[0113] The molded article may be a part, a cover or a cover part of an electronic control unit (ECU) including an engine control unit, a transmission (TCU), an electronic stability control (ESC), an airbag control, a tire pressure management (TPMS), and a occupant classification sensing system (PODS) of an automobile, among others.

[0114] The electronic control unit part, its cover or its cover part can be manufactured by a step of extruding or injecting the polyester composition at a molding temperature of 230 to 300°C, preferably 250 to 290°C. Within this range, a product without defects can be obtained, and the manufacturing time of the molded product can be shortened, thereby reducing manufacturing costs.

[0115] By adjusting the impact strength, tensile strength and flexural strength of the molded article within the above ranges, the impact resistance can be improved, and thus the durability of the molded article can be improved.

[0116] In describing the polyester resin composition, its production method, and molded products, other conditions and equipment not explicitly described herein can be appropriately selected within the range commonly used in the art, and it is clearly stated that there are no particular limitations.

[0117] Hereinafter, the present invention will be described in detail with reference to the examples so that those skilled in the art can easily carry out the present invention. However, the present invention can be realized in various different forms and is not limited to the examples described here. In addition, % herein means % by weight unless otherwise specified.

[0118] [Example] In one embodiment of the present invention, the components used in the preparation of the polyester resin composition are as follows: (A) Polybutylene terephthalate resin (PBT, intrinsic viscosity 0.7-1.12 dl / g, Mw 10,000-80,000 g / mol), Thunhe, TH6082A (B) Polyethylene terephthalate resin (B-1) Co-PET (PET containing 5-50 mol% isophthalic acid units, intrinsic viscosity 0.5-1.0 dl / g, Mw 5,000-80,000 g / mol), TK Chemical, Tex Pet 874-C80 (B-2) Homo-PET (intrinsic viscosity 0.5-1.0 dl / g, Mw 5,000-80,000 g / mol), SK Chemicals, BB8055 (B-3) Homo-PET (intrinsic viscosity 1.0-1.2 dl / g, Mw 5,000-80,000 g / mol), Huvis, JSB 599 (C) Reinforcing fiber: Diameter 7-15 μm, length 3-6 mm, composition: glass fiber with 40-50% silica, 10-20% aluminum oxide, and 30-40% calcium oxide, NEG, T-187H product Here, % means % by weight. (D) Layered clay minerals (D-1) MICA: MICA 200DX (D-2) Talc: KC-3000C, KOCH (D-3) Calcium carbonate (E) Additives (E-1) Heat stabilizer: Irganox 1010 (E-2) Lubricant: PE wax (product name LC102N) (E-3) Carbon black masterbatch (product name NB 9089)

[0119] Examples 1 to 2 and Comparative Examples 1 to 6 According to the components and contents shown in Table 1 below, the (A) polybutylene terephthalate resin, (B-1) to (B-3) polyethylene terephthalate resin, (C) reinforcing fiber, (D-1) talc, (D-2) mica, (D-3) calcium carbonate, (E-1) heat stabilizer, (E-2) lubricant, and (E-3) carbon black master batch were mixed, and then melted and kneaded in a temperature range of 250 to 290°C using a twin-screw extruder with L / D = 42 and Φ = 40 mm to prepare a polyester resin composition in a pellet state. The (E-1) and (E-2) were added in a combined content of 0.8 wt% in the entire polyester resin composition, filling the total amount of 100 wt%.

[0120] The produced resin pellets were dried at 120℃ for more than 4 hours, and then injected at an injection speed of 40mm / s at an injection temperature of 260~290℃ and a mold temperature of 80℃ using a 280ton electric injection machine (Sumitomo Co., Ltd.) to produce test pieces with a thickness of 2T and dimensions of 200mm x 100mm. These were then stored at room temperature.

[0121] [Test example] The properties of the test pieces produced in Examples 1 and 2 and Comparative Examples 1 to 6 were measured by the following methods, and the results are shown in Table 1 below. *Low warpage characteristics: The height dimensions of the manufactured test pieces, which are 200 mm wide x 100 mm long and have a thickness of 2T, were measured before and after they were left at a temperature of 100°C for 30 minutes. *Tensile strength (Mpa), tensile modulus (MPa) and elongation (%): Each was measured in accordance with ISO 527-12. *Flexural strength (MPa) and flexural modulus (Mpa): Measured in accordance with ISO 178. *Charpy notch impact strength (kJ / m 2 ):Measured in accordance with ISO 179. *Heat distortion temperature (℃): Measured in accordance with ISO 75.

[0122] [Table 1]

[0123] As shown in Table 1, in the case of Examples 1 and 2 according to the present invention, specific amounts of polybutylene terephthalate resin, polyethylene terephthalate resin containing isophthalic acid units, reinforcing fiber, mica and additives were included, and it was confirmed that deformation including warpage was minimized even under high temperature conditions while maintaining a balance between mechanical strength and heat resistance, thereby significantly improving low warpage characteristics.

[0124] On the other hand, in the case of Comparative Example 1, the heat resistance was further improved by including polybutylene terephthalate resin, polyethylene terephthalate resin not containing isophthalic acid units, reinforcing fiber, talc and additives, but it was found that the low warpage property could not be adequately improved.

[0125] In addition, in the case of Comparative Example 2, it was found that the reinforcing fiber was added at an inappropriate content ratio compared to the mica, resulting in poor mechanical strength and inability to adequately improve low warpage characteristics.

[0126] In addition, in the case of Comparative Example 3, it was found that by using a polyethylene terephthalate resin not containing an isophthalic acid unit, not only was the mechanical strength poor, but also the low warpage property could not be appropriately improved.

[0127] In addition, in the case of Comparative Example 4, it was found that the inclusion of a small amount of polybutylene terephthalate resin and an excessive amount of polyethylene terephthalate resin not containing isophthalic acid units not only significantly reduced the heat resistance, but also made it impossible to adequately improve the low warpage characteristics.

[0128] In addition, in the case of Comparative Example 5, it was found that not only was the mechanical strength significantly reduced by including polybutylene terephthalate resin, polyethylene terephthalate resin not containing isophthalic acid units, reinforcing fibers, calcium carbonate, and additives, but also that the low warpage characteristics could not be adequately improved.

[0129] In addition, in the case of Comparative Example 6, it was found that the low warpage characteristics were reduced by including an excess amount of polybutylene terephthalate resin and a small amount of polyethylene terephthalate resin containing isophthalic acid units.

[0130] In conclusion, it was confirmed that the material is suitable for parts, covers, or cover parts of electronic control units including automobile engine control units, transmissions (TCU), electronic stability control (ESC), airbag control, tire pressure management (TPMS), and occupant classification sensing systems (PODS). By controlling the structure and content of polyethylene terephthalate resin mixed with polybutylene terephthalate resin and adjusting the weight ratio of reinforcing fiber and layered clay mineral, it is possible to maintain a balance between mechanical strength and heat resistance, as well as maintain flatness and minimize deformation even in high temperature environments, making it suitable for use in the fields of automobile parts, covers, or cover parts.

Claims

1. 30 to 45% by weight of polybutylene terephthalate resin; 23 to 35% by weight of polyethylene terephthalate resin; 23 to 28% by weight of reinforcing fibers; and 5 to 10% by weight of layered clay minerals; The polyester resin composition, wherein the polyethylene terephthalate resin contains isophthalic acid.

2. The polyester resin composition according to claim 1, wherein the polybutylene terephthalate resin has a weight average molecular weight (Mw) of 20,000 to 100,000 g / mol and a melting point of 200 to 240° C. as measured by DSC.

3. The polyester resin composition according to claim 1, wherein the polyethylene terephthalate resin has a melting point of 200 to 270° C. as measured by DSC.

4. 2. The polyester resin composition according to claim 1, wherein the reinforcing fiber is a glass fiber containing 20 to 65% by weight of silica, 1 to 40% by weight of aluminum oxide, 10 to 60% by weight of calcium oxide, and 5% by weight or less of one or more selected from iron oxide, magnesia, sodium oxide, iron, and boron oxide, and having a diameter of 7 to 15 μm and a length of 3 to 6 mm.

5. The layered clay mineral is selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite. The polyester resin composition according to claim 1, wherein the layered clay mineral is selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite, and hydrotalcite.

6. The polyester resin composition according to claim 1, further comprising one or more additives selected from a heat stabilizer, a UV stabilizer, a lubricant, a plasticizer, a flame retardant, a flame retardant auxiliary, a colorant, a release agent, a pigment, a dye, an ester exchange reaction inhibitor, an antistatic agent, an antibacterial agent, a processing aid, a metal deactivator, a fluorine-based drip prevention agent, and a colored master batch in an amount within a range of 0.1 to 5% by weight based on 100% by weight of all components constituting the polyester resin composition.

7. The polyester resin composition according to claim 1, wherein a test piece having a width x length of 200 mm x length of 100 mm and a thickness of 2T has a difference in height in the height direction of 0.25 mm or less before and after being left at a temperature of 100°C for 30 minutes.

8. 2. The polyester resin composition according to claim 1, wherein the polyester resin composition has a flexural modulus measured according to ISO 178 of 8120 MPa or more.

9. The polyester resin composition according to claim 1, characterized in that the polyester resin composition has a heat distortion temperature (HDT) of 190° C. or more measured under conditions of ISO 75-1 / 2 and 1.80 MPa.

10. The method includes the steps of kneading and extruding 30 to 45% by weight of polybutylene terephthalate resin, 23 to 35% by weight of polyethylene terephthalate resin, 23 to 28% by weight of reinforcing fiber, and 5 to 10% by weight of layered clay mineral; The method for producing a polyester resin composition, wherein the polyethylene terephthalate resin contains isophthalic acid.

11. The layered clay mineral is selected from the group consisting of mica, montmorillonite, bentonite, kaolinite, hectorite, fluorinated hectorite, saponite, beidellite, nontronite, stevensite, vermiculite, halloysite, volkonskoite, sauconite, magadiite, kenyaite and hydrotalcite. The method for producing a polyester resin composition according to claim 10.

12. A molded article comprising the polyester resin composition described in any one of claims 1 to 9.

13. The molded article according to claim 12, wherein the molded article is a part, a cover or a cover part of an electronic control unit including an engine control unit, a transmission control unit (TCU), an electronic stability control (ESC) system, an airbag control system, a tire pressure management system (TPMS), and a passenger area detection system (PODS).

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