Polyester resin composition, molded article, tableware, tableware tray, cosmetic container, food and beverage container, cosmetic container, food and beverage container, and injection molding method

Abstract

To provide polyester resin compositions and the like that exhibit rapid crystallization, excellent heat resistance, dimensional stability, mechanical strength, and moldability, and are suitable for use in injection molding. [Solution] The polyester resin composition contains 70% by mass or more of polyethylene terephthalate resin, whose main constituent units are repeating units consisting of terephthalic acid units and ethylene glycol units, 1% by mass to 5% by mass of a crystal nucleating agent, and 100 ppm by mass to 2,000 ppm by mass of a mold release agent. Using a test piece injected from the polyester resin composition, (1) the heating crystallization heat ΔH, which is the integral value of the peak area of ​​the exothermic behavior when the temperature is raised from 30°C to 300°C at 10°C / min by differential scanning calorimetry, is 5 J / g or less, (2) the thermal shrinkage rate before and after heat treatment at 120°C for 300 minutes is 0.2% or less, and (3) the load deflection temperature at 0.45 MPa, measured in accordance with ISO 075, is 120°C or higher.

Description

[Technical Field]

[0001] The present invention relates to polyester resin compositions, molded articles, tableware, tableware trays, cosmetic containers, food and beverage containers, cosmetic containers, food and beverage containers, and injection molding methods. [Background technology]

[0002] Conventionally, molded articles made from polyester resin compositions have been widely used for household goods, cosmetic containers, tableware, and dish trays, but there is a problem that the insufficient heat resistance of the molded articles causes deformation of household goods and cosmetic containers in the summer, and deformation of tableware and dish trays in dishwashers.

[0003] To solve the aforementioned problem, it has been proposed to use heat-resistant monomers such as dimethyl 2,6-naphthalenedicarboxylate (NDCM) or isosorbide (ISB) to improve the heat resistance of polyester resins (see, for example, Patent Document 1).

[0004] Furthermore, it has been proposed to improve the heat resistance of polyester resins by adding nucleating agents such as talc to promote crystallization (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-177942 [Patent Document 2] Japanese Patent Publication No. 2023-24333 [Overview of the project] [Problems that the invention aims to solve]

[0006] As described in Patent Document 1 above, using specific heat-resistant monomers leads to increased costs compared to general-purpose monomers, and also presents the challenge of requiring equipment and manufacturing processes specifically for using those particular heat-resistant monomers.

[0007] In methods that improve heat resistance by adding a nucleating agent, such as the one described in Patent Document 2 above, injection molding is difficult because the polyester resin is rapidly cooled in the mold from a molten state, unlike vacuum forming where the thickness of the molded body is constant and reheating in the mold is possible. Furthermore, the holding time (cooling time) in the mold is longer, which reduces productivity. Moreover, injection-molded bodies have a high degree of freedom in shape and often do not have a constant thickness. For these reasons, injection molding is prone to uneven crystallization of the injection-molded body, and is susceptible to molding defects such as sink marks, poor appearance, and poor mold release. As a result, the widespread use of injection molding using polyester resin compositions is currently hindered.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a polyester resin composition, molded articles, tableware, tableware trays, cosmetic containers, food and beverage containers, cosmetic containers, food and beverage containers, and injection molding methods that exhibit rapid crystallization, excellent heat resistance, dimensional stability, mechanical strength, and moldability, and are suitable for injection molding. [Means for solving the problem]

[0009] The means to solve the aforementioned problems are as follows:

[0010] The polyester resin composition of the present invention comprises 70% by mass or more of polyethylene terephthalate resin, whose main constituent units are repeating units consisting of terephthalic acid units and ethylene glycol units; 1% by mass to 5% by mass of a crystal nucleating agent; and 100 ppm by mass to 2,000 ppm by mass of a mold release agent. Using a test piece injection-molded from the polyester resin composition, (1) the heat of crystallization ΔH, which is the integral value of the peak area of ​​the exothermic behavior when the temperature is raised from 30°C to 300°C at a rate of 10°C / min by differential scanning calorimetry, is 5 J / g or less; (2) the thermal shrinkage rate before and after heat treatment at 120°C for 300 minutes is 0.2% or less; and (3) the heat deflection temperature at 0.45 MPa, measured in accordance with ISO 075, is 120°C or higher.

[0011] Furthermore, the polyester resin composition has a Charpy impact strength of 2.0 kJ / m², as measured in accordance with ISO 179. 2 It is preferable that the above conditions are met. Furthermore, the polyester resin composition preferably has an intrinsic viscosity of polyethylene terephthalate resin of 0.5 dl / g to 0.9 dl / g. Furthermore, it is preferable that the polyester resin composition has an average particle size of 3 μm to 15 μm for the nucleating agent. Furthermore, it is preferable that the polyester resin composition contains talc as a nucleating agent. Furthermore, it is preferable that the release agent in the polyester resin composition is a stearic acid ester compound. Furthermore, the polyester resin composition is preferably suitable for injection molding.

[0012] The molded article of the present invention is formed from the polyester resin composition of the present invention. Furthermore, it is preferable that the molded body is a piece of tableware containing the molded body of the present invention. Furthermore, it is preferable that the molded body is a tableware tray containing the molded body of the present invention. Furthermore, it is preferable that the molded body is a cosmetic container containing the molded body of the present invention. Furthermore, it is preferable that the molded body is a food and beverage container containing the molded body of the present invention.

[0013] The cosmetic container of the present invention comprises the cosmetic container of the present invention and the cosmetic product filled inside the cosmetic container, and is highly resistant to ingredients contained in the cosmetic product that could adversely affect the cosmetic container.

[0014] The food and beverage container of the present invention comprises the food and beverage container of the present invention and the food and beverage filled inside the food and beverage container, and has high resistance to components contained in the food and beverage that adversely affect the food and beverage container.

[0015] The injection molding method of the present invention involves heating the polyester resin composition of the present invention, injecting the melted melt into a mold, and maintaining the mold temperature at 130°C to 160°C. Furthermore, in the injection molding method, after injecting the melt into the mold and taking out the molded product from the mold, it is preferable not to perform heating to a mold temperature of 130°C to 160°C or higher. Also, in the injection molding method, it is preferable to add the crystal nucleating agent in the form of a masterbatch to the polyester resin composition.

Effects of the Invention

[0016] According to the present invention, it is possible to provide a polyester resin composition, a molded product, tableware, a tableware tray, a cosmetic container, a food and beverage container, a container containing cosmetics, a container containing food and beverages, and an injection molding method that have fast crystallization, excellent heat resistance, dimensional stability, mechanical strength, and moldability, and are suitably used for injection molding.

Modes for Carrying Out the Invention

[0017] (Polyester Resin Composition) The polyester resin composition of the present invention contains a polyethylene terephthalate resin, a crystal nucleating agent, and a mold release agent, and further contains other components as necessary.

[0018] In the present invention, by injection molding a polyester resin composition in which 1% to 5% by mass of a crystal nucleating agent and 100 ppm to 2,000 ppm by mass of a mold release agent are blended with respect to the polyethylene terephthalate resin, crystallization can be promoted and sufficient crystallization can be achieved, so that a molded product having excellent crystallinity, heat resistance, dimensional stability, mechanical strength, and moldability (mold release property and appearance) can be molded. [[ID=?]]

[0019] <Polyethylene Terephthalate Resin> The polyethylene terephthalate resin has repeating units composed of terephthalic acid units and ethylene glycol units as main constituent units.

[0020] It should be noted that there seems to be a mislabeled "了0000095" in the original text which is retained as is in the translation for the purpose of following the rules. If this is an error, it may need to be corrected in the original text source for a more accurate translation.Here, "main constituent unit" usually refers to a constituent unit that is present in polyethylene terephthalate resin at a concentration of 80% by mass or more. The content of the main constituent unit is preferably 90% by mass or more, more preferably 95% by mass or more, and may also be completely free of any constituent units other than the main constituent unit (100% by mass).

[0021] Polyethylene terephthalate resin is a polymer whose main constituent units are repeating units consisting of terephthalic acid units and ethylene glycol units. Each of these repeating units is also called a compound unit for the compound from which it originates. For example, repeating units derived from terephthalic acid are called "terephthalic acid units," and repeating units derived from ethylene glycol are called "ethylene glycol units."

[0022] Polyethylene terephthalate resin may contain copolymer units to the extent that it does not impair its crystallinity.

[0023] The copolymer units preferably include dicarboxylic acid units other than terephthalic acid units and / or alcohol units other than ethylene glycol units. Examples of dicarboxylic acid units other than terephthalic acid units include isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,4-franglicarboxylic acid, 2,5-franglicarboxylic acid, adipic acid, sebacic acid, succinic acid, dimer acid, 1,4-cyclohexadicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl 2,6-naphthalenedicarboxylic acid, dimethyl 2,4-franglicarboxylic acid, dimethyl 2,5-franglicarboxylic acid, or derivatives thereof. These may be used individually or in combination of two or more. Among these, isophthalic acid units are preferred.

[0024] Examples of alcohol units other than ethylene glycol units include 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, or derivatives thereof. These may be used individually or in combination of two or more.

[0025] The polyester resin composition of the present invention may also contain other polyester resins in addition to polyethylene terephthalate resin, as long as their crystallinity is not impaired.

[0026] Other polyester resins include, for example, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN), and polytrimethylene terephthalate (PTT). Among these, polybutylene terephthalate (PBT) resin is particularly preferred. When polybutylene terephthalate (PBT) resin is incorporated, the PBT resin content is preferably less than 30% by mass, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total amount of the polyester resin composition.

[0027] As the polyethylene terephthalate resin, a synthetically produced resin may be used as appropriate, or a commercially available product may be used. The method for synthesizing the polyethylene terephthalate resin will be explained later in the section on the manufacturing method of polyethylene terephthalate resin.

[0028] As the polyethylene terephthalate resin, scraps generated during film production or molding can be used. This enables efficient resource utilization and reduction of manufacturing costs. The scraps may be processed into easily usable forms such as pellets, flakes, or powder. Furthermore, the polyethylene terephthalate resin may contain units derived from recycled polyester resin or units derived from biomass.

[0029] The polyethylene terephthalate resin content is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 97% by mass or more, and may be 100% by mass, based on the total amount of the polyester resin composition. If the polyethylene terephthalate resin content is less than 70% by mass, the heat resistance will decrease, and the deflection temperature under load at 0.45 MPa may fall below 120°C.

[0030] The intrinsic viscosity (IV) of polyethylene terephthalate resin is preferably 0.5 dl / g to 0.9 dl / g, and more preferably 0.6 dl / g to 0.8 dl / g. The intrinsic viscosity was measured at 20°C using an automatic viscosity analyzer equipped with an Ubbelohde viscometer, after dissolving 0.5000±0.0005g of polyethylene terephthalate resin in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio).

[0031] <Method for manufacturing polyethylene terephthalate resin> Polyethylene terephthalate resin can be produced by known methods based on the monomers and other components of the raw materials described above. For example, an ester prepolymer may be produced by direct esterification using an unsubstituted polycarboxylic acid as a starting material, or by a transesterification reaction using an esterified product such as a dimethyl ester as a starting material. From the viewpoint of production efficiency, it is preferable to select a direct esterification reaction.

[0032] Direct esterification or transesterification reactions can be carried out, for example, by charging the raw materials into a reaction vessel equipped with a heating device, a stirrer, and a distillation tube, adding a reaction catalyst, and raising the temperature while stirring under an inert gas atmosphere at atmospheric pressure, while allowing the reaction to proceed while distilling off by-products such as water and methanol produced by the reaction. The reaction temperature can be, for example, 150°C to 270°C, and is preferably 160°C to 260°C. The reaction time is, for example, about 3 to 7 hours.

[0033] At least one metal compound can be used as a catalyst for the transesterification reaction. Examples of metal compounds include sodium, potassium, calcium, titanium, lithium, magnesium, manganese, zinc, tin, and cobalt. Of these, titanium and manganese compounds are preferred because they are highly reactive and produce a good color tone in the resulting polyethylene terephthalate resin. The amount of transesterification catalyst added is preferably 5 ppm to 1,000 ppm, and more preferably 10 ppm to 100 ppm, relative to the polyethylene terephthalate resin produced.

[0034] To suppress the formation of diethylene glycol as a byproduct, it is preferable to reduce the amount of ethylene glycol in the reaction system. For example, it is preferable to set the molar ratio of alcohol units to acid units (alcohol units / acid units) to 1.3 or less. Alternatively, the formation of diethylene glycol can be suppressed by adding, for example, 5 ppm of sodium hydroxide.

[0035] Furthermore, it is preferable to add a phosphorus compound after the direct esterification reaction or transesterification reaction has been completed to allow the esterification reaction to proceed further. Examples of phosphorus compounds include phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trimethyl phosphite, triethyl phosphite, and tributyl phosphite. Among these, trimethyl phosphate is particularly preferred. The amount of phosphorus compound used is preferably 5 ppm to 1,000 ppm, and more preferably 20 ppm to 100 ppm, relative to the mass of the polyethylene terephthalate resin produced.

[0036] Following the transesterification and esterification reactions, a polymerization catalyst can be added to the ester prepolymer, and a polycondensation reaction can be carried out further until the desired molecular weight is achieved. For example, germanium dioxide can be suitably used as the catalyst in the polymerization reaction. The addition rate of the polymerization catalyst can be, for example, 180 ppm to 220 ppm relative to the amount of resin produced. The polycondensation reaction can be carried out, for example, by gradually increasing the temperature and reducing the pressure inside the reaction vessel after adding the polymerization catalyst. The pressure inside the vessel can be reduced to, for example, ultimately 0.4 kPa or less, preferably 0.2 kPa or less. The temperature inside the vessel can be preferably increased to, for example, ultimately 250°C to 290°C. The polymerization reaction can be carried out, for example, under reduced pressure until a predetermined melt viscosity is achieved, with the final internal pressure of the vessel being 150 Pa or less. Afterward, the internal pressure can be increased to, for example, 0.5 MPa, and the reaction product can be pushed out from the bottom of the vessel and recovered. For example, the reaction product can be extruded into water in a strand shape, cooled, and then cut to obtain pelletized polyethylene terephthalate resin.

[0037] Other catalysts besides germanium dioxide can be used as polymerization catalysts. For example, titanium dioxide can be used as a polymerization catalyst. When using titanium dioxide, the addition rate of the polymerization catalyst can be, for example, 1 ppm to 10 ppm relative to the amount of polyethylene terephthalate resin produced.

[0038] Polyethylene terephthalate resin can be appropriately blended with various additives, such as lubricants, antioxidants, heat stabilizers, antistatic agents, plasticizers, UV absorbers, and pigments, depending on the application and molding purpose. These additives may be added during either the polymerization reaction process or the processing and molding process.

[0039] <Crystallizing agent> There are no particular restrictions on the nucleating agent, and it can be appropriately selected depending on the purpose. For example, inorganic or organic nucleating agents can be used.

[0040] Examples of inorganic nucleating agents include inorganic powders such as talc, mica, aluminum silicate, aluminum calcium silicate, silica, boron nitride, and metal oxides.

[0041] Examples of organic crystal nucleating agents include alkali metal salts of organic carboxylic acids, organic nitrogen-containing compounds, and zinc phenylphosphonate. Examples of alkali metal salts of organic carboxylic acids include sodium benzoate, potassium benzoate, lithium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, sodium octacosanoate, sodium stearate, potassium stearate, lithium stearate, sodium montanate, sodium tolulate, sodium salicylate, potassium salicylate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, and sodium cyclohexanecarboxylate. Examples of organic nitrogen-containing compounds include lauric acid amide, stearic acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide, ethylenebis-12-hydroxystearic acid amide, palmitic acid amide, and hydroxystearic acid amide.

[0042] The aforementioned nucleating agent may be used alone or in combination of two or more. Among these, talc is preferred from the viewpoint of crystallization rate.

[0043] The average particle size of the nucleating agent is preferably 3 μm to 15 μm, and more preferably 5 μm to 13 μm. If the average particle size of the nucleating agent exceeds 15 μm, the crystallization rate may decrease, and the heat resistance may be reduced. If the average particle size of the nucleating agent is less than 3 μm, it may not be possible to promote the crystallization of the PET resin. In addition, a large amount of nucleating agent must be added, leading to increased costs. The average particle size of the nucleating agent is determined using a laser diffraction particle size analyzer (wet method) to obtain the "volume-based cumulative 50% particle size (D 50 )”

[0044] The content of the nucleating agent is 1% to 5% by mass, preferably 1% to 4% by mass, more preferably 2% to 4% by mass, and even more preferably 2% to 3% by mass, based on the total amount of the polyester resin composition. If the content of the nucleating agent is less than 1% by mass, the heat resistance decreases, and the deflection temperature at 0.45 MPa becomes less than 120°C. On the other hand, if the content of the nucleating agent exceeds 5% by mass, the dispersibility of the nucleating agent deteriorates, the mechanical properties of the molded article decrease, and the release properties may be poor.

[0045] The polyester resin composition of the present invention may contain a crystallization accelerator together with a crystallization nucleating agent, from the viewpoint of promoting crystallization. Examples of crystallization accelerators include carbonates, metal phosphate salts, calcium phosphates, sulfonates, aromatic carboxamides, metal soaps, ionomers, polyethylene, polypropylene, and polystyrene.

[0046] <Release agent> Stearic acid ester compounds are preferably used as release agents. As the stearic acid ester compound, partial or total esters of stearic acid with a substituted or unsubstituted monohydric or polyhydric alcohol having 1 to 20 carbon atoms are preferred. Examples of partial or full esters of monohydric or polyhydric alcohols with stearic acid include monoglyceride stearate, diglyceride stearate, triglyceride stearate, monosorbite stearate, stearyl stearate, pentaerythritol monostearate, pentaerythritol tetrastearate, propylene glycol monostearate, stearyl stearate, butyl stearate, sorbitan monostearate, and 2-ethylhexyl stearate. These may be used individually or in combination of two or more.

[0047] The release agent may include other release agents besides stearic acid ester compounds. Other release agents include, for example, fatty acid esters such as behenyl behenate, pentaerythritol tetrabehenate, and ethylene glycol distearate; polyolefin waxes such as low molecular weight polyethylene and low molecular weight polypropylene; branched hydrocarbon waxes such as microcrystalline wax; long-chain hydrocarbon waxes such as paraffin wax and sazole wax; dialkylketone waxes such as distearyl ketone; fatty acid amide waxes such as ethylenediamine behenylamide and trimellitic acid tristearylamide; and metal salts of fatty acids such as magnesium stearate and calcium stearate. These may be used individually or in combination of two or more.

[0048] The release agent content is 100 ppm to 2,000 ppm by mass (0.01% to 0.2% by mass) relative to the total amount of the polyester resin composition, preferably 100 ppm to 1,500 ppm by mass, more preferably 150 ppm to 1,500 ppm by mass, even more preferably 200 ppm to 1,000 ppm by mass, particularly preferably 300 ppm to 1,000 ppm by mass, and most particularly preferably 300 ppm to 500 ppm by mass. If the release agent content exceeds 2,000 ppm by mass, the amount of material adhering to the mold during molding may increase, resulting in a defective appearance of the molded product. On the other hand, if the release agent content is less than 100 ppm by mass, the release properties may decrease, and the molded product may not be able to be released from the mold during molding.

[0049] The polyester resin composition of the present invention has excellent heat resistance and mechanical strength, and therefore substantially does not contain glass fibers, which were conventionally added to improve mechanical strength and heat resistance. When glass fibers are included, warping of the molded article due to anisotropy caused by the orientation of the glass fibers, embrittlement of the weld (resin junction), and defects in the appearance of the molded article may occur. In addition, the specific gravity increases, making the molded article heavier. Furthermore, it increases the load on the equipment due to wear of molds and molding machines, and leads to increased manufacturing costs.

[0050] <Other ingredients> Other components are not particularly limited and can be selected as appropriate depending on the purpose. Examples include various additives such as antioxidants, heat stabilizers, antistatic agents, plasticizers, UV absorbers, pigments, inorganic fillers, flame retardants, and foaming agents.

[0051] In the polyester resin composition of the present invention, using a test piece injected from the polyester resin composition, (1) the heat of crystallization ΔH, which is the integral value of the peak area of ​​the exothermic behavior when the temperature is raised from 30°C to 300°C at a rate of 10°C / min by differential scanning calorimetry, is 5 J / g or less; (2) the thermal shrinkage rate before and after heat treatment at 120°C for 300 minutes is 0.2% or less; and (3) the temperature of deflection under load at 0.45 MPa, measured in accordance with ISO 075, is 120°C or higher. Furthermore, (4) the Charpy impact strength, measured in accordance with ISO 179, is 2.0 kJ / m 2 It is preferable that the above conditions are met.

[0052] Specifically, the test specimens that can be used are those prepared in the following manner.

[0053] <Preparation of test specimens> Using an injection molding machine (MD75XA, manufactured by Niigata Machine Techno Co., Ltd.), a dumbbell-shaped test piece measuring 170 mm in length, 10 mm in width, and 4 mm in thickness was fabricated by setting the cylinder temperature to 280°C, the mold temperature to 130°C-150°C, the injection speed to 10 mm / s, and the holding pressure to 80 MPa for 5 seconds, followed by a holding time (cooling time) of 30 to 60 seconds. Furthermore, using the same molding conditions as the dumbbell-shaped test specimen described above, a strip-shaped test specimen measuring 80 mm in length, 4 mm in thickness, and 10 mm in width was prepared.

[0054] (1) Using the dumbbell-shaped test piece, the heat of crystallization during heating ΔH, which is the integral value of the peak area of ​​the exothermic behavior due to crystallization during heating when the temperature is increased from 30°C to 10°C / min under a nitrogen atmosphere using a differential scanning calorimetry device, is 5 J / g or less, preferably 2 J / g or less, and more preferably 0 J / g (no peak). When the heat of crystallization during heating ΔH is 5 J / g or less, the molded body is sufficiently crystallized. In this invention, because the degree of crystallinity of the molded body is sufficiently high, there is almost no additional crystallization due to heating in the first scan of the DSC of the molded body, and the peak area of ​​the heat of heating for crystallization ΔH becomes small.

[0055] (2) The heat shrinkage rate before and after heat-treating the dumbbell-shaped test piece at 120°C for 300 minutes is 0.2% or less, preferably 0.1% or less, and may even be 0% (no dimensional change). When the heat shrinkage rate is 0.2% or less, it specifically means that the dimensional stability of the molded body is high. After setting the dumbbell-shaped test piece in a forced-air oven heated to 120°C, let it stand for 300 minutes (5 hours). Measure the length of the test piece before standing (A). After 300 minutes at 120°C, take out the test piece from the forced-air oven and measure its length (B). From the measured lengths A and B, the heat shrinkage rate (%) = [(A - B) / A] × 100 can be calculated.

[0056] (3) The deflection temperature under load at 0.45 MPa of the strip-shaped test piece measured in accordance with ISO075 is 120°C or higher, preferably 130°C or higher, more preferably 140°C or higher, and even more preferably 150°C or higher. When the deflection temperature under load at 0.45 MPa is 120°C or higher, it indicates that the molded body has high heat resistance.

[0057] (4) The Charpy impact strength of the strip-shaped test piece measured in accordance with ISO179 is 2.0 kJ / m 2 or higher, preferably 2.0 kJ / m 2 ~ 5.0 kJ / m 2 is more preferable, and 2.0 kJ / m 2 ~ 3.0 kJ / m 2 is even more preferable. The Charpy impact strength is a value measured in accordance with ISO179 using three test pieces (test piece shape: length 80 mm, thickness 4 mm, width 10 mm, with notch). When the Charpy impact strength is 2 kJ / m 2 or higher, it indicates that the molded body has high mechanical strength (impact resistance).

[0058] The polyester resin composition of the present invention preferably has a tensile strength of 50 MPa to 100 MPa, more preferably 60 MPa to 80 MPa. Furthermore, the tensile elongation is preferably 1% to 10%, more preferably 3% to 8%. The tensile strength and tensile elongation were measured in accordance with ISO 527 using three dumbbell-shaped test specimens (test specimen dimensions: total length 170 mm, thickness 4 mm, width 10 mm, gauge length 75 mm).

[0059] The polyester resin composition of the present invention preferably has a flexural strength of 50 MPa to 150 MPa, more preferably 70 MPa to 120 MPa. Furthermore, it preferably has a flexural modulus of 1 GPa to 5 GPa, more preferably 1 GPa to 3 GPa. The flexural strength and flexural modulus were measured in accordance with ISO 178 using five strip-shaped test pieces (test piece dimensions: length 80 mm, thickness 4 mm, width 10 mm).

[0060] The polyester resin composition of the present invention is suitable for injection molding due to its rapid crystallization, and is suitable for use in the injection molding method of the present invention described below.

[0061] (Injection molding method) The injection molding method of the present invention involves heating the polyester resin composition of the present invention, injecting the molten material into a mold, and holding it at a mold temperature of 130°C to 160°C. A mold temperature of 130°C to 150°C is preferred during holding. If the mold temperature is below 130°C, crystallization near the surface of the molded body will be insufficient, reducing its heat resistance, and the deflection temperature at 0.45 MPa may fall below 120°C. On the other hand, if the mold temperature exceeds 160°C, cooling will take longer, increasing the cycle time and reducing productivity, or the mold release properties may deteriorate because the molded body cannot be cooled sufficiently.

[0062] The holding time varies depending on the shape of the molded body, and if the molded body is thin, the time required for crystallization to occur throughout the body will be shorter, while if it is thick, the time required will be longer. Therefore, it is difficult to specify a general time.

[0063] While it is desirable to set the holding time as short as possible from the viewpoint of production efficiency, in this invention, it is necessary that the molded body is sufficiently crystallized when it is removed from the mold. For this reason, the holding time must be sufficient for the crystallization of the molded body, that is, it must be at least the time required for the peak area of ​​the heat of crystallization ΔH in the 1st DSC scan of the molded body to be 5 J / g or less.

[0064] In the injection molding method of the present invention, it is preferable that the molded body is not heated to a temperature above 130°C to 160°C after being removed from the mold from the mold, in addition to injecting a molten polyester resin composition into the mold. That is, in the present invention, the molded body is not reheated in an oven or the like after being removed from the mold in order to crystallize it. As a result, the number of steps required for the manufacture of the molded body is reduced, making it possible to produce molded bodies efficiently.

[0065] In injection molding, it is preferable to add the nucleating agent in the polyester resin composition in the form of a masterbatch. Adding the nucleating agent in the form of a masterbatch prevents aggregation of the added nucleating agent. Furthermore, the dispersibility of the nucleating agent is improved, and the heat resistance of the polyester resin composition is enhanced.

[0066] The polyester resin composition of the present invention exhibits rapid crystallization, excellent heat resistance, dimensional stability, mechanical strength, and moldability, and is therefore widely used in various technical fields. In particular, it is suitably used for molded articles such as tableware, tableware trays, cosmetic containers, and food and beverage containers, as described below.

[0067] (Molded body) The molded article of the present invention is formed from the polyester resin composition of the present invention, and is preferably an injection-molded article formed by injection molding.

[0068] The aforementioned molded body is preferably a piece of tableware containing the molded body of the present invention. There are no particular restrictions on the types of tableware that can be used. Examples include soup bowls, rice bowls, tea bowls, bowls, donburi bowls, plates, mugs, milk jug, syrup jug, coffee cups, chopsticks, forks, spoons, glasses, and bowls.

[0069] The molded body is preferably a tableware tray containing the molded body of the present invention. The tableware tray is a tray for storing tableware.

[0070] <Cosmetic containers> The molded body is preferably a cosmetic container containing the molded body of the present invention. Cosmetic containers are not particularly limited in shape as long as they have a space that can hold cosmetics, for example, a hollow structure or a recessed area. Therefore, the shape of cosmetic containers is not limited to bottles or dispensers, but can be various shapes such as jars, tubes, or compact containers.

[0071] <Food and beverage containers> The aforementioned molded body is preferably a food and beverage container containing the molded body of the present invention. Food and beverage containers are not particularly limited in shape as long as they have a space that can hold food and beverages, for example, a hollow structure or a recess. Therefore, food and beverage containers can take on various shapes such as bags, trays, containers, bottles, and tubes.

[0072] The cosmetic container, which is a molded product of the present invention, has excellent heat resistance, dimensional stability, mechanical strength, and moldability, and is particularly resistant to ingredients contained in cosmetics that can adversely affect cosmetic containers. Therefore, it is suitable for use in cosmetic containers as described below.

[0073] (Cosmetic container) The cosmetic container of the present invention comprises the cosmetic container of the present invention and the cosmetic product filled inside the cosmetic container, and is highly resistant to ingredients contained in the cosmetic product that could adversely affect the cosmetic container.

[0074] Cosmetics are not particularly limited, but examples include perfumes, creams, lotions, toners, face masks, foundations, lip balms, lipsticks, hair tonics, hair lotions, shampoos, rinses, and conditioners.

[0075] Adverse effects on cosmetic containers refer to risks such as adverse effects from cosmetic ingredients degrading the physical properties of the container, causing the container to deteriorate, or the risk of cosmetic products leaching out of the container.

[0076] The main ingredients in cosmetics that can negatively affect cosmetic containers are listed below. (1) Ethanol (ethyl alcohol) Ethanol, found in cosmetics, can be particularly corrosive to plastic containers, potentially causing degradation and brittleness of the plastic over time.

[0077] (2) Essential oils and fragrances High concentrations of essential oils or fragrances can dissolve plastic containers or make them brittle. They can also penetrate the rubber gaskets of containers, causing them to lose their elasticity.

[0078] (3) Acidic components (AHA, BHA, etc.) Acidic components such as alpha hydroxy acids (AHAs) or beta hydroxy acids (BHAs) contained in cosmetics can corrode plastic containers. In addition, some plastics (especially non-acid resistant plastics) are susceptible to acid and may deteriorate more quickly.

[0079] (4) Surfactants Some surfactants contained in cosmetics can affect plastics over time, potentially degrading the physical properties of the containers.

[0080] (5) UV absorbers Some UV absorbers in cosmetics can chemically decompose when exposed to light, potentially causing chemical changes within the container and damaging it.

[0081] (6) Silicone The silicones contained in cosmetics can affect certain plastic materials, potentially degrading the physical properties of the containers.

[0082] (7) Antioxidants Antioxidants contained in cosmetics, such as dibutylhydroxytoluene (BHT), ascorbic acid, and tocopherol, can undergo chemical changes within the container when exposed to light and air, potentially damaging the plastic container.

[0083] Therefore, selecting appropriate cosmetic containers based on the ingredients in the cosmetics that could negatively affect the containers is crucial for maintaining the quality and safety of cosmetics.

[0084] The molded food and beverage container of the present invention exhibits excellent heat resistance, dimensional stability, mechanical strength, and moldability, and is particularly resistant to components in food and beverages that can adversely affect the container. Therefore, it is suitable for use in food and beverage containers as described below.

[0085] (Containers containing food and beverages) The food and beverage container of the present invention comprises the food and beverage container of the present invention and the food and beverage filled inside the food and beverage container, and has high resistance to components contained in the food and beverage that adversely affect the food and beverage container.

[0086] Food and beverages include, but are not limited to, beverages such as soft drinks, carbonated drinks, nutritional drinks, fruit drinks, and lactic acid drinks (including concentrated concentrates and powders for adjusting these beverages); frozen desserts such as ice cream, ice sherbet, and shaved ice; noodles such as soba, udon, vermicelli, gyoza wrappers, shumai wrappers, Chinese noodles, and instant noodles; confectionery such as candy, chewing gum, chocolate, tablets, snacks, biscuits, jelly, jam, cream, and baked goods; processed seafood and livestock products such as kamaboko, ham, and sausage; dairy products such as processed milk and fermented milk; seafood, oils and fats such as salad oil, tempura oil, margarine, mayonnaise, shortening, whipped cream, and dressings; seasonings such as sauces and dips; soups, stews, salads, prepared foods, and pickles; and various other forms of health and nutritional supplements; and beverages.

[0087] Adverse effects on food and beverage containers refer to risks such as adverse components in food and beverages reducing the physical properties of the container, causing deterioration of the container, or the risk of food and beverages leaching from the container.

[0088] The main ingredients in food and beverages that can adversely affect food and beverage containers are listed below. (1) Acidic components (e.g., vinegar, tomatoes, citrus fruits, etc.) Some plastics (especially non-acid resistant plastics) are susceptible to acid, which can accelerate the deterioration of containers.

[0089] (2) Ethanol (ethyl alcohol) Foods and beverages containing ethanol (such as wine, beer, and spirits) can cause certain plastic containers (especially polystyrene or polycarbonate) to swell or reduce their strength. Furthermore, prolonged contact with ethanol may cause food and beverages to leach out of the containers.

[0090] (3) Oils and fats (foods high in fat) Oily and fatty foods (such as fried foods, butter, and oil) can affect certain plastic containers. In particular, when oil is absorbed into plastic, it can soften or chemically alter the plastic. Oils and fats have the property of extracting additives and stabilizers from plastics, which can degrade the physical performance of the container.

[0091] (4) Salt content (salted foods, seafood, etc.) Prolonged contact between salty foods and beverages and plastic containers can accelerate the deterioration of the plastic.

[0092] (5) Enzymes and fermented foods Fermented foods (such as yogurt, kimchi, and pickles) can negatively affect certain plastic containers. The gases and acids produced during fermentation can cause the containers to deteriorate, and the expansion of these gases can cause the containers to deform.

[0093] (6) High-temperature foods and beverages High temperatures can damage plastic containers. Heat can soften the plastic, potentially causing food or beverages to leach out. Polycarbonate or polystyrene containers are particularly susceptible to heat damage.

[0094] (7) Sugars (e.g., syrup, jam, etc.) High-sugar foods and beverages can affect the surface of certain plastic containers and accelerate their deterioration over time. When sugar crystallizes, the surface of the container can become more susceptible to scratches.

[0095] (8) Carbon dioxide (e.g., carbonated drinks) Carbon dioxide can put pressure on plastic, potentially causing deformation or rupture of the container. Additionally, the gas can penetrate the inside of the container, potentially degrading the plastic. (9) Photosensitive components (e.g., vitamin C, oils and fats) Some ingredients in food and beverages are easily broken down when exposed to light, and chemical changes can easily occur inside the container. Plastic containers, being highly transparent to light, can accelerate the oxidation and deterioration of food and beverages.

[0096] Therefore, selecting appropriate food and beverage containers based on the ingredients in the food and beverages that can adversely affect the containers is crucial for maintaining the quality and safety of food and beverages. [Examples]

[0097] The following describes embodiments of the present invention, but the present invention is not limited in any way to these embodiments.

[0098] (Synthesis Example 1) -Synthesis of polyethylene terephthalate resin 1- A mixture was prepared using 100 mol% terephthalic acid as the acid and 100 mol% ethylene glycol as the diol, with a molar ratio of 1.2 between the acid and the diol. This mixture was charged into a reactor equipped with a stirrer, a rectification column, and a water distillation condenser. The temperature was raised from 190°C to 260°C over 3 hours, and the esterification reaction was carried out while distilling off the generated water. After the esterification reaction was complete, 223 ppm antimony trioxide and 13 ppm triethyl phosphoric acid were added, and the temperature was gradually raised from 260°C to 280°C over 60 minutes. The pressure was also gradually reduced from atmospheric pressure to 1 torr to terminate the reaction at the desired viscosity. The mixture was then extruded into cooling water and pelletized using a strand cutter. The polyethylene terephthalate resin 1 obtained in Synthesis Example 1 had an intrinsic viscosity of 0.65 dl / g, as measured as follows.

[0099] <Intrinsic viscosity> 0.5000±0.0005g of polyester resin was dissolved in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio), and the intrinsic viscosity (IV) of the polyethylene terephthalate resin at 20°C was measured using an automatic viscometer (AVL-6C, manufactured by Sun Electronics Industry Co., Ltd.).

[0100] (Synthesis Example 2) -Synthesis of polyethylene terephthalate resin 2- In Synthesis Example 1, the polyethylene terephthalate resin 2 of Synthesis Example 2 was synthesized in the same manner as in Synthesis Example 1, except that after the polymerization reaction was completed, the pressure was gradually reduced from atmospheric pressure to 1 torr to adjust the intrinsic viscosity (IV) to 0.74 dl / g.

[0101] (Synthesis Example 3) -Synthesis of polybutylene terephthalate resin- A mixture was prepared by charging 100 mol% dimethyl terephthalate as the acid, 100 mol% butanediol as the diol, and 10 ppm of a Ti-based compound relative to the amount of resin (based on the number of Ti atoms), with a molar ratio of 1.2 of diol to acid. This mixture was then charged into a reactor equipped with a stirrer, a rectification column, and a water distillation condenser. The temperature was raised from 160°C to 230°C over 5 hours, and the transesterification reaction was carried out while distilling off the generated methanol. After the transesterification reaction was complete, 30 ppm of the Ti-based compound (based on the number of Ti atoms) and 500 ppm of a phenolic antioxidant were added. The temperature was gradually raised from 230°C to 240°C over 120 minutes, and the pressure was gradually reduced from atmospheric pressure to 1 torr to terminate the reaction at the desired viscosity. The mixture was then extruded into cooling water and pelletized using a strand cutter. The intrinsic viscosity of the polybutylene terephthalate (PBT) resin obtained in synthesis example 3 was 0.785 dl / g.

[0102] (Test examples 1-23) Based on the compositions shown in Table 1, the polyester resin compositions for Test Examples 1 to 23 were prepared. In Test Example 23 in Table 1, the PBT used was the homo-PBT resin from Synthesis Example 3. Specifically, Test Example 23 used a mixed resin consisting of 50.00% by mass of PET resin from Synthesis Example 1 and 45.95% by mass of PBT resin from Synthesis Example 3.

[0103] The following were used as nucleating agents in Table 1. • Nucleating agents: Talc with average particle sizes of 5 μm, 13 μm, and 20 μm, and boron nitride with an average particle size of 5 μm were prepared. The average particle size of the nucleating agents was determined using a laser diffraction particle size analyzer (wet method) to obtain the "volume-based cumulative 50% particle size (D 50 )” For all test examples except for test examples 13, 14, 19, and 20, a masterbatch (MB) prepared by mixing the PET and nucleating agent used in each test example in a 1:1 mass ratio was added in the amounts shown in Table 1.

[0104] The following release agents were used in Table 1. • Release agent: Stearic acid ester (stearyl stearate) or calcium stearate was prepared.

[0105] Next, using the obtained polyester resin composition, test specimens were prepared as follows, based on the molding conditions shown in Table 2.

[0106] <Preparation of test specimens> Using an injection molding machine (MD75XA, manufactured by Niigata Machine Techno Co., Ltd.), a dumbbell-shaped test specimen measuring 170 mm in length, 10 mm in width, and 4 mm in thickness was fabricated by holding the cylinder at 280°C, the mold temperature as shown in Table 2, the injection speed at 10 mm / s, and the holding pressure at 80 MPa for 5 seconds, with the holding time (cooling time) as shown in Table 2. Furthermore, a strip-shaped test specimen measuring 80 mm in length, 4 mm in thickness, and 10 mm in width was prepared using the same molding conditions as the dumbbell-shaped test specimen described above.

[0107] Next, the prepared test specimens were used to evaluate various properties as described below. The results are shown in Tables 2 to 4.

[0108] <Glass transition temperature Tg and heat of crystallization ΔH (crystallinity)> Using the dumbbell-shaped test specimens prepared as described above, a differential scanning calorimetry system (TA Instruments, DSC-2500) was used to raise the temperature from 30°C to 300°C at a rate of 10°C / min under a nitrogen atmosphere. The midpoint temperature of the endothermic behavior due to the glass transition was defined as the glass transition temperature (Tg). Using the prepared test specimens, the temperature was increased from 30°C to 300°C at a rate of 10°C / min under a nitrogen atmosphere. The heat of crystallization due to heating, ΔH (J / g), which is the integral value of the peak area of ​​the exothermic behavior due to heating crystallization, was determined, and the crystallinity was evaluated according to the following criteria. [Evaluation Criteria] ○: Heat of crystallization ΔH is 5 J / g or less. ×: Heat of crystallization ΔH exceeds 5 J / g

[0109] <Temperature of deflection under load (heat resistance)> In accordance with ISO075, the deflection temperature under load was measured at 0.45 MPa and 1.80 MPa for three of the aforementioned strip-shaped test specimens, and the average value for each load was calculated. Based on the average deflection temperature under load at 0.45 MPa, the heat resistance was evaluated according to the following criteria. [Evaluation Criteria] ○: Above 120℃ ×: Below 120℃

[0110] <Dimensional Stability> The dumbbell-shaped test specimens prepared as described above were placed in a forced-air oven heated to 60°C, 80°C, or 120°C, and left to stand for 300 minutes (5 hours). The length of the test specimen was measured before standing (A). After 300 minutes, the test specimen was removed from the forced-air oven and its length was measured (B). From the measured lengths A and B, the thermal shrinkage rate (%) = [(AB) / A] × 100 was calculated. Based on the thermal shrinkage rate at 120°C, dimensional stability was evaluated according to the following criteria. [Evaluation Criteria] ○: Thermal shrinkage rate of 0.2% or less ×: Thermal shrinkage rate greater than 0.2%

[0111] <Mold releasability> In the preparation of the aforementioned test specimens, the presence or absence of deformation of the test specimen was determined when the specimen was removed from the mold after injection molding, and the release properties were evaluated according to the following criteria. [Evaluation Criteria] ○: No deformation of the test piece occurred during demolding, and continuous molding is possible. ×: Deformation of the test piece occurs during demolding, making continuous molding impossible.

[0112] <Exterior> The appearance of the test specimens (molded bodies) prepared as described above was evaluated according to the following criteria. [Evaluation Criteria] ○: Good appearance ×: The shape of the test specimen is abnormal, or wrinkles have formed on the surface of the test specimen.

[0113] <Cycleability> The cycle time (in seconds) for one cycle of producing the aforementioned test specimen was measured, and the cycleability was evaluated according to the following criteria. Longer cycle times result in decreased productivity. One cycle refers to the time taken for the entire process of mold closing, injection molding, holding pressure molding, cooling, mold opening, and removal of the molded product. [Evaluation Criteria] ○: Cycle time between 30 seconds and 80 seconds ×: Cycle time less than 30 seconds or more than 80 seconds

[0114] <Tensile strength and tensile elongation> In accordance with ISO 527, the tensile strength and tensile elongation were measured for three test specimens (specimen shape: total length 170 mm, thickness 4 mm, width 10 mm, gauge length 75 mm), and the average values ​​were calculated.

[0115] <Bending strength and bending modulus> In accordance with ISO 178, the bending strength and bending modulus were measured for five test specimens (specimen shape: length 80 mm, thickness 4 mm, width 10 mm), and the average values ​​were calculated.

[0116] <Charpy impact strength> In accordance with ISO 179, the Charpy impact strength was measured for three test specimens (specimen shape: length 80 mm, thickness 4 mm, width 10 mm, with notch), the average value was calculated, and the results were evaluated according to the following criteria. [Evaluation Criteria] ○: Charpy impact strength is 2.0 kJ / m 2 That's all. ×: Charpy impact strength is 2.0 kJ / m 2 less than

[0117] <Overall Rating> Based on the evaluation results for crystallinity, heat resistance, dimensional stability, Charpy impact strength, mold release properties, and appearance described above, a comprehensive evaluation was conducted according to the following criteria. [Evaluation Criteria] No evaluation results available for ○:×. ×:× evaluation results available.

[0118] [Table 1]

[0119] [Table 2] *The presence or absence of crystal nucleating agent aggregation can be determined by observing the surface of the molded body. If aggregation occurs, unevenness in light and dark areas will appear on the surface of the molded body.

[0120] [Table 3]

[0121] [Table 4]

[0122] From the results in Tables 1 to 4, it was found that Test Examples 1 to 12 satisfy all of the following requirements (A) to (F), preferably (G), and therefore, polyester resin compositions and molded articles with rapid crystallization and excellent heat resistance, dimensional stability, mechanical strength, mold release properties, and appearance can be obtained. (A) A polyethylene terephthalate resin having repeating units consisting of terephthalic acid units and ethylene glycol units as its main constituent units, comprising 70% by mass or more, (B) The nucleating agent is 1% to 5% by mass, (C) A polyester resin composition containing a release agent in an amount of 100 ppm to 2,000 ppm by mass. For test specimens injection-molded from the polyester resin composition, (D) the heat of crystallization ΔH, which is the integral value of the peak area of ​​the exothermic behavior when the temperature is raised from 30°C to 300°C at a rate of 10°C / min as measured by differential scanning calorimetry, is 5 J / g or less; (E) the thermal shrinkage rate before and after heat treatment at 120°C for 300 minutes is 0.2% or less; and (F) the deflection temperature at a load of 0.45 MPa, measured in accordance with ISO 075, is 120°C or higher. Furthermore, preferably, the Charpy impact strength measured in accordance with (G)ISO179 is 2.0 kJ / m². 2 That's all.

[0123] In contrast, Test Example 13 did not meet the requirements of (B), (D), (E), (F), and (G) above, resulting in slow crystallization and inferior mechanical strength, heat resistance, mold release properties, and dimensional stability.

[0124] Test example 14 did not meet the requirements of (B), (D), (E), and (F) above, resulting in slow crystallization and poor heat resistance and dimensional stability.

[0125] Test example 15 did not meet the requirements of (E) and (F) above, resulting in poor dimensional stability, heat resistance, mold release properties, and appearance.

[0126] Test example 16 did not meet the requirements of (E) and (F) above, resulting in poor heat resistance and dimensional stability.

[0127] Test example 17 did not meet the requirements of (B), (D), (E), and (F) above. Due to the low content of the nucleating agent, crystallization took a long time, the cycle time was extended, and the result was poor heat resistance, dimensional stability, release properties, and appearance.

[0128] Test example 18 did not meet the requirements of (B) and (G) above, resulting in inferior mechanical strength, release properties, and appearance.

[0129] Test Example 19 failed to meet the requirements of (E), (D), (F), and (G) above, resulting in a long crystallization time and inferior mechanical strength, heat resistance, dimensional stability, mold release properties, and appearance. Furthermore, because the nucleating agent was added directly rather than in a masterbatch, aggregation of the nucleating agent occurred.

[0130] Test example 20 failed to meet the requirements of (C), (E), (F), and (G) above, resulting in inferior mechanical strength, heat resistance, dimensional stability, release properties, and appearance.

[0131] Test example 21 did not meet the requirements of (C) above, and therefore resulted in an inferior appearance.

[0132] Test example 22 failed to meet the requirements of (E), (F), and (G) above, resulting in inferior mechanical strength, heat resistance, dimensional stability, release properties, and appearance.

[0133] Test example 23 did not meet the requirements of (A) and (F) above, and therefore showed poor heat resistance. [Industrial applicability]

[0134] The polyester resin composition and molded articles of the present invention exhibit rapid crystallization, excellent heat resistance, dimensional stability, mechanical strength, and moldability, and are particularly suitable for injection molding. Therefore, they can be widely used in various technical fields, such as tableware, tableware trays, cosmetic containers, food and beverage containers, cosmetic containers, and food and beverage containers.

Claims

1. A polyethylene terephthalate resin comprising 70% by mass or more, whose main constituent units are repeating units consisting of terephthalic acid units and ethylene glycol units, The nucleating agent is added in an amount of 1% to 5% by mass, A polyester resin composition comprising a release agent in an amount of 100 ppm to 2,000 ppm by mass, A polyester resin composition characterized in that, using a test piece injected from the polyester resin composition, (1) the heat of crystallization ΔH, which is the integral value of the peak area of ​​the exothermic behavior when the temperature is raised from 30°C to 300°C at a rate of 10°C / min by differential scanning calorimetry, is 5 J / g or less; (2) the thermal shrinkage rate before and after heat treatment at 120°C for 300 minutes is 0.2% or less; and (3) the heat deflection temperature at 0.45 MPa measured in accordance with ISO 075 is 120°C or higher.

2. The Charpy impact strength, measured in accordance with ISO 179, was 2.0 kJ / m². ２ The polyester resin composition according to claim 1.

3. The polyester resin composition according to claim 1, wherein the intrinsic viscosity of the polyethylene terephthalate resin is 0.5 dl / g to 0.9 dl / g.

4. The polyester resin composition according to claim 1, wherein the average particle size of the nucleating agent is 3 μm to 15 μm.

5. The polyester resin composition according to claim 1, wherein the nucleating agent is talc.

6. The polyester resin composition according to claim 1, wherein the mold release agent is a stearic acid ester compound.

7. A polyester resin composition according to claim 1, for use in injection molding.

8. A molded article formed from the polyester resin composition described in any one of claims 1 to 7.

9. A tableware comprising the molded body described in claim 8.

10. A tableware tray comprising the molded body described in claim 8.

11. A cosmetic container comprising the molded body described in claim 8.

12. A food and beverage container comprising the molded body described in claim 8.

13. A cosmetic container comprising a cosmetic container according to claim 11 and a cosmetic product filled inside the cosmetic container, characterized in that it has high resistance to ingredients contained in the cosmetic product that adversely affect the cosmetic container.

14. A food and beverage container comprising a food and beverage container according to claim 12 and food and beverage filled inside the food and beverage container, characterized in that it has high resistance to components contained in the food and beverage that adversely affect the food and beverage container.

15. An injection molding method characterized by heating a polyester resin composition according to any one of claims 1 to 7, injecting the melted material into a mold, and maintaining the mold temperature at 130°C to 160°C.

16. The injection molding method according to claim 15, wherein the molten material is injected into a mold, and after removing the molded body from the mold, no heating is performed to a mold temperature of 130°C to 160°C or higher.

17. The injection molding method according to claim 15, wherein a crystal nucleating agent is added to the polyester resin composition in the form of a masterbatch.

Images