Resin composition, sheet, laminate, and thermoformed article

Abstract

Resin composition and tray resistant to brittle fracture in low-temperature environment SOLUTION: A composition comprising a polylactic acid, a biodegradable polyester having a melting temperature of 40 to 125 °C and an enthalpy of fusion ΔH of 0 to 60J / g, and talc, wherein the composition does not contain a carboxamide and satisfies the following requirement A: The polylactic acid, the biodegradable polyester, and the talc are contained in amounts of 45 to 65 parts by mass, 25 to 45 parts by mass, and 7 to 15 parts by mass, respectively, with respect to 100 parts by mass in total of the polylactic acid, the biodegradable polyester, and the talc, and the parts by mass of the polylactic acid is larger than the parts by mass of the biodegradable polyester. 35J.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a sheet, a laminate, and a thermoformed article. [Background technology]

[0002] Various resin compositions containing polylactic acid have been disclosed. Patent Document 1 discloses that in order to improve the efficiency of thermoforming, a resin composition containing at least polylactic acid (A), a block copolymer of polylactic acid and an aliphatic polyester (B), and talc (C) having an average particle size of 2 to 10 μm is molded into a sheet, and that the crystallinity is controlled to a predetermined value by precise control during vacuum molding, thereby ensuring heat resistance and impact resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-46005 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional trays made of resin compositions containing polylactic acid are susceptible to brittle fracture in low-temperature environments, and there is room for improvement.

[0005] An object of the present invention is to provide a resin composition and a laminate that contain polylactic acid and are resistant to brittle fracture in low-temperature environments. [Means for solving the problem]

[0006] After extensive research, the inventors discovered that thermoformed trays made from a resin composition containing polylactic acid, a specific biodegradable polyester, and talc in a specific blend are more likely to undergo ductile fracture rather than brittle fracture even in low-temperature environments, leading to the invention.

[0007] [1] A biodegradable polyester containing polylactic acid, a biodegradable polyester having a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g, and talc; Does not contain carboxylic acid amides A resin composition that satisfies either of the following requirements A or B. Requirement A: The biodegradable polyester has a melting enthalpy ΔH of 35 J / g or less, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 65 parts by mass, 25 to 45 parts by mass, and 7 to 15 parts by mass, respectively, per 100 parts by mass of the polylactic acid, biodegradable polyester, and talc combined, and the parts by mass of the polylactic acid are greater than the parts by mass of the biodegradable polyester. Requirement B: The melting enthalpy ΔH of the biodegradable polyester is greater than 35 J / g and not greater than 60 J / g, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 55 parts by mass, 35 to 45 parts by mass, and 7 to 15 parts by mass, respectively, per 100 parts by mass of the polylactic acid, biodegradable polyester, and talc combined, and the parts by mass of the polylactic acid are greater than the parts by mass of the biodegradable polyester. [2] The resin composition according to [1], which satisfies requirement A. [3] A sheet of the resin composition according to [1]. [4] A laminate including a first resin composition layer, a second resin composition layer, and a third resin composition layer in this order, the first resin composition layer, the second resin composition layer, and the third resin composition layer each contain polylactic acid, a biodegradable polyester having a melting point of 125°C or less and a melting enthalpy ΔH of 0 to 60 J / g, and talc; In the first resin composition layer, the mass fraction of the biodegradable polyester relative to the total mass of the polylactic acid, the biodegradable polyester, and the talc is defined as X1, and the melting enthalpy of the biodegradable polyester is defined as ΔH1 (J / g), In the second resin composition layer, the mass fraction of the biodegradable polyester relative to the total mass of the polylactic acid, the biodegradable polyester, and the talc is defined as X2, and the melting enthalpy of the biodegradable polyester is defined as ΔH2 (J / g), When the mass fraction of the biodegradable polyester with respect to the total mass of the polylactic acid, the biodegradable polyester, and the talc in the third resin composition layer is X3, and the melting enthalpy of the biodegradable polyester is ΔH3 (J / g), it satisfies X1 / ΔH1 < X2 / ΔH2 and X3 / ΔH3 < X2 / ΔH2 A laminate in which each of the first resin composition layer, the second resin composition layer, and the third resin composition layer is the resin composition according to claim 1. A thermoformed product of the sheet according to [5] [3] or the laminate according to [4]. The thermoformed product according to [5], which is a tray. [Effect of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition that contains polylactic acid and is less likely to undergo brittle fracture in a low-temperature environment. [Brief Description of the Drawings]

[0009] [Figure 1] It is a schematic cross-sectional view of the tray 200 according to the embodiment. [Figure 2] It is a schematic cross-sectional view of the laminate according to the embodiment. [Modes for Carrying Out the Invention]

[0010] [[ID=3x4]] Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0011] (Resin Composition) The composition according to the present embodiment contains polylactic acid; a biodegradable polyester having a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g; and talc, and does not contain carboxylic acid amide.

[0012] (Polylactic Acid) The polylactic acid may be poly(L-lactic acid), poly(D-lactic acid), or a mixture or copolymer thereof. From the viewpoints of biodegradability and moldability, it is preferable to use poly(L-lactic acid) as the main component.

[0013] The melting point of polylactic acid mainly composed of poly(L-lactic acid) varies depending on the optical purity. In this embodiment, however, taking into consideration the mechanical properties, heat resistance, and moldability of the molded article, the melting point is preferably 160°C or higher. The melting point of polylactic acid may be 170°C or higher or 180°C or lower. In polylactic acid mainly composed of poly(L-lactic acid), the melting point of 160°C or higher can be achieved by setting the proportion of D-lactic acid components (D-isomer content) to less than about 3 mol%. In particular, to improve the crystallization performance of the polylactic acid resin and thereby improve heat resistance and moldability, it is preferable to use one with a D-isomer content of less than 2 mol%.

[0014] There are no limitations on the melt flow rate of the polylactic acid, and the melt flow rate at 190° C. and 2.16 kgf may be, for example, 0.3 to 30 g / 10 min.

[0015] (biodegradable polyester) Biodegradable polyesters have a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g. In this specification, biodegradable polyesters do not include polylactic acid. The melting point of biodegradable polyesters is preferably 60°C or higher, and more preferably 80°C or higher.

[0016] The enthalpy of fusion may be 50 J / g or less, 30 J / g or less, or 20 J / g or less. The enthalpy of fusion is measured by differential scanning calorimetry (DSC) in a N2 atmosphere at a heating rate of 10°C / min.

[0017] Examples of such biodegradable polyesters include aliphatic aromatic polyesters such as polybutylene adipate terephthalate (PBAT: melting point, for example, 110 to 120°C), and aliphatic polyesters such as polybutylene succinate (PBS: melting point, for example, 80 to 120°C).

[0018] For example, BASF's Ecoflex is a PBAT having a melting point of 117°C and a melting enthalpy ΔH of 12 J / g.

[0019] Mitsubishi Chemical's BioPBS (FD92PM) has a melting point of 83°C and a melting enthalpy ΔH of 48 J / g.

[0020] The biodegradable polyester according to this embodiment may be a mixture.

[0021] (talc) The talc may be in the form of powder, and may have an average particle size of 0.5 to 25 μm. The average particle size is D50 of the particle size distribution on a volume basis determined by laser diffraction method.

[0022] (carboxylic acid amide) The composition of this embodiment does not contain a carboxylic acid amide. Resin compositions containing polylactic acid often contain a carboxylic acid amide as a mold release agent, but the composition of this embodiment does not contain a carboxylic acid amide.

[0023] Examples of the carboxylic acid amide are erucic acid amide, stearic acid amide, oleic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, and ethylene bislauric acid amide.

[0024] The composition of the present embodiment preferably does not contain any release agent other than the carboxylic acid amide.

[0025] (Composition of three components) The resin composition of the present embodiment satisfies either requirement A or B below.

[0026] Requirement A: The melting enthalpy ΔH of the biodegradable polyester is 35 J / g or less, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 65 parts by mass, 25 to 45 parts by mass, and 7 to 15 parts by mass, respectively, per 100 parts by mass of the total of polylactic acid, biodegradable polyester, and talc, and the parts by mass of polylactic acid are greater than the parts by mass of biodegradable polyester.

[0027] Requirement B: The melting enthalpy ΔH of the biodegradable polyester is greater than 35 J / g and not greater than 60 J / g, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 55 parts by mass, 35 to 45 parts by mass, and 7 to 15 parts by mass, respectively, per 100 parts by mass of the total of polylactic acid, biodegradable polyester, and talc, and the parts by mass of polylactic acid are greater than the parts by mass of biodegradable polyester.

[0028] In particular, it is preferable that the composition satisfies requirement A.

[0029] (additives) The composition may further contain various additives, such as antioxidants, ultraviolet absorbers, antistatic agents, lubricants, anti-fogging agents, anti-blocking agents, and deodorizers.

[0030] There are no particular limitations on the amount of additives added to the resin composition, and each additive may be added in an amount of 1% by mass or less based on the composition.

[0031] (Overall composition) In the resin composition, the total mass proportion of polylactic acid, biodegradable polyester, and talc may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 98% by mass or more.

[0032] (Method of producing resin composition) The above composition can be obtained by melt-kneading polylactic acid, a biodegradable polyester having a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g, talc, and additives that are added as needed.

[0033] The temperature during kneading is preferably 210° C. or lower, 205° C. or lower, preferably 200° C. or lower, preferably 195° C. or lower, and also preferably 190° C. or lower. The temperature is preferably 180° C. or higher, and may be 185° C.

[0034] The composition can be pelletized to form a molding material.

[0035] (sheet) The sheet of this embodiment is a sheet of the above-mentioned resin composition. Such a sheet can be obtained by extrusion molding the above-mentioned resin composition using a T-die. The thickness of the sheet can be set to 0.2 to 1.0 mm.

[0036] The sheet of the present embodiment may have a layer of a resin other than the sheet of the resin composition described above.

[0037] (tray) The tray according to this embodiment is an example of a thermoformed product of a resin composition such as the above-mentioned sheet, etc. An example of a tray 200 thermoformed from a sheet 50 is shown in FIG.

[0038] From the viewpoint of exhibiting cold impact resistance and mold releasability, it is preferable to heat the resin composition such as the above-mentioned sheet to 100 to 150°C, apply it to a mold at 110 to 130°C to mold it, and then slowly cool it for about 10 seconds to crystallize the polylactic acid in particular. Crystallization increases rigidity and improves mold releasability. Therefore, it is preferable that the thermoformed product of the above sheet has no exothermic peak indicating crystallization in a DSC curve obtained by, for example, heating at a rate of 10°C / min using a DSC, and that the material is in a state where crystallization is as advanced as possible.

[0039] The trays are particularly suitable for food applications. Such trays have excellent low-temperature properties for frozen processing, frozen transportation, etc. They can also be used under high-temperature conditions such as microwave cooking.

[0040] Thermoformed products may be materials used in household appliances such as refrigerator components and automobiles, as well as trays. Thermoforming is a method of heating a thermoplastic resin sheet to a molding temperature and then pressing it into a mold to form it, such as hot plate forming, vacuum forming, vacuum pressure forming, and pressure forming.

[0041] (Action and effect) According to this embodiment, the thermoformed product such as a tray obtained is excellent in cold impact resistance in that it is likely to undergo ductile fracture rather than brittle fracture in an impact test in a low-temperature environment. The reason for this is unclear, but the following action is thought to be involved.

[0042] Biodegradable polyesters with a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g act as rubber components in comparison with crystalline polylactic acid, and are therefore thought to be more susceptible to ductile fracture rather than brittle fracture.

[0043] Biodegradable polyesters with a melting enthalpy of 35 J / g or less are less crystalline and more likely to function as rubber components, so it is thought that they can be effective in smaller amounts than biodegradable polyesters with a melting enthalpy of more than 35 J / g.

[0044] If the fusion enthalpy exceeds 60 J / g, it is thought that the rubber component will not function as well as it should.

[0045] Furthermore, the resin composition according to this embodiment exhibits improved mold releasability and reduced molding cycle time despite not containing a carboxylic acid amide as a mold release agent. The reason for this is unclear, but it is thought to be due to the fact that the amount of biodegradable polyester is less than the amount of polylactic acid, the amount of polylactic acid is neither too much nor too little, and the resin composition contains a sufficient amount of talc, which can function as a crystal nucleating agent, thereby promoting crystallization of the resin composition in the mold.

[0046] In addition, since the resin composition does not contain a carboxylic acid amide, it is possible to suppress the situation where the carboxylic acid amide blocks the vacuum holes of the mold or the bleed product of the carboxylic acid amide accumulates on the mold surface to an insufficient extent, and it is also possible to reduce problems such as the shaping of the molded body becoming loose or the surface of the molded body not being able to be shaped neatly.

[0047] Also, in this embodiment, the heat resistance of the tray is also maintained high.

[0048] (Laminate) As shown in FIG. 2, the laminate 100 according to this embodiment is a laminate including a first resin composition layer 10, a second resin composition layer 20, and a third resin composition layer 30 in this order. The laminate may be a sheet.

[0049] The first resin composition layer 10, the second resin composition layer 20, and the third resin composition layer 30 each contain polylactic acid, a biodegradable polyester having a melting point of 125° C. or lower and a melting enthalpy ΔH of 0 to 60 J / g, and talc.

[0050] Each component is as described in the column of the resin composition, and the description thereof is omitted.

[0051] In the first resin composition layer 10, let the mass fraction of the biodegradable polyester with respect to the total mass of polylactic acid, the biodegradable polyester, and talc be X1, and the melting enthalpy of the biodegradable polyester be ΔH1 (J / g). In the second resin composition layer 20, let the mass fraction of the biodegradable polyester with respect to the total mass of polylactic acid, the biodegradable polyester, and talc be X2, and the melting enthalpy of the biodegradable polyester be ΔH2 (J / g). When the mass fraction of the biodegradable polyester with respect to the total mass of polylactic acid, the biodegradable polyester, and talc in the third resin composition layer 30 is X3, and the melting enthalpy of the biodegradable polyester is ΔH3 (J / g), X1 / ΔH1 < X2 / ΔH2 and X3 / ΔH3 < X2 / ΔH2 are satisfied.

[0052] The larger X, the greater the amount of biodegradable polyester, which is the rubber component, and the smaller ΔH (the larger 1 / ΔH), the more amorphous (rubber characteristics) the biodegradable polyester, which is the rubber component, becomes.

[0053] The first formula above means that the second resin composition layer 20, which is the intermediate layer, has greater rubber properties and less crystallinity than the first resin composition layer 10, which is the outer layer.

[0054] The second formula above means that the second resin composition layer 20, which is the intermediate layer, has greater rubber properties and less crystallinity than the third resin composition layer 30, which is the outer layer.

[0055] In this configuration, the rubber properties of the intermediate layer are enhanced to make it more susceptible to ductile fracture in low temperature environments, while the crystallinity of the outer layer is relatively maintained to improve releasability from a mold.

[0056] Therefore, it is easy to achieve both cold impact resistance and mold releasability.

[0057] For example, if the same type of biodegradable polyester is used in the first resin composition layer 10, the third resin composition layer 30, and the second resin composition layer 20, the ΔH is the same, so the amount of biodegradable polyester in the intermediate layer is higher.

[0058] For example, when the biodegradable polyesters used in the first resin composition layer 10 and the third resin composition layer 30 are different from those used in the second resin composition layer 20, the following combinations are possible.

[0059] For example, the ΔH of the biodegradable polyester in the first resin composition layer 10 and the third resin composition layer 30 is larger than the ΔH of the biodegradable polyester in the second resin composition layer 20, and the blending ratio of the biodegradable polyester in the first resin composition layer 10 and the third resin composition layer 30 is the same as that in the second resin composition layer 20, or the blending ratio of the biodegradable polyester in the second resin composition layer 20 is smaller than that in the first and third resin composition layers.

[0060] The resin composition of each layer satisfies the above-mentioned resin composition formulation.

[0061] The total thickness of the first and third resin composition layers can be 20 to 70% of the total thickness of the first to third resin composition layers, the thickness of the second resin composition layer can be 80 to 30% of the total thickness of the first to third resin composition layers, and the total thickness of the first to third resin composition layers can be 0.2 to 1.0 mm.

[0062] Such a laminate can be obtained by coextrusion using a T-die or the like.

[0063] (tray) The tray according to this embodiment is an example of a thermoformed product of the above-mentioned laminate.

[0064] From the viewpoint of exhibiting good cold impact resistance and releasability, it is preferable to heat the laminate to 100 to 150°C, press it against a mold at 110 to 130°C to form it, and then slowly cool it for about 10 seconds to crystallize it.

[0065] The trays are particularly suitable for food applications.

[0066] Such trays have excellent low-temperature properties for freezing treatment, frozen transportation, etc. They can also be used under high-temperature conditions such as microwave cooking.

[0067] The thermoformed product may be a material used in household appliances such as a fitting cover, refrigerator components, or automobiles, in addition to a tray. [Example]

[0068] (raw materials) PLA (L175): Total Corbion L175, d = 1.24 g / cm 3 , MFR(190℃, 2.16kg)3g / 10min, Tm=175℃ PLA (L130): Total Corbion L130, d = 1.24 g / cm 3 , MFR(190℃, 2.16kg)10g / 10min, Tm=175℃ PBAT(C1200): BASF Ecoflex C1200, d=1.24g / cm 3 , MFR(190℃, 2.16kg)3.8g / 10min, Tm=117℃ bioPBS: Mitsubishi Chemical BioPBS FD92PM: d=1.24g / cm 3 , MFR(190℃, 2.16kg)4g / 10min, Tm=84℃ bioPBS: Mitsubishi Chemical BioPBS FZ91PM: d=1.26g / cm 3 , MFR(190℃, 2.16kg)5g / 10min, Tm=112℃ Talc: Asada Flour Milling Co., Ltd. JM-300, average particle size D50 = 5 μm

[0069] (Measurement of enthalpy of fusion ΔH, melting point) Approximately 10 mg of each sample was placed in an aluminum pan and heated using a DSC (differential scanning calorimeter) from 20 to 200°C at a heating rate of 10°C / min (first heating), and held at 200°C for 5 minutes. The sample was then cooled to 20°C at a heating rate of 10°C / min (cooling), and held at 20°C for 5 minutes. The sample was then heated to 200°C at a heating rate of 10°C / min (second heating). The endothermic peak of the DSC curve during this second heating was determined and used as the melting point. The area of ​​the endothermic peak divided by the weight of the sample placed in the pan was used as the enthalpy of fusion (ΔH). Table 1 shows the various physical properties of polylactic acid, PBAT, and PBS.

[0070] [Table 1]

[0071] (Single layer: Examples 1 to 5 and Comparative Examples 1 to 6) (Manufacturing of single layer sheets) The raw materials having the composition (parts by mass) shown in Table 2 were melt-kneaded in a φ50 mm extruder set at 200°C, extruded through a 300 mm wide T-die, and cooled and solidified with a polishing roll to obtain a single-layer sheet having a thickness of 500 μm.

[0072] (vacuum forming of trays) The obtained single-layer sheet was attached to a batch-type vacuum forming machine and heated from above and below for 6 seconds using a heater set at 500°C. When the sheet surface temperature reached 125°C, the heater was removed and the sheet was vacuum-formed into a tray (150mm x 120mm x depth 30mm) to obtain a tray for evaluation. The mold temperature was set to 120°C, and the sheet was slowly cooled to allow crystallization.

[0073] (evaluation) (Measurement of tray strength in DuPont impact test) The 50% breaking energy E50(J) of the tray was measured using a DuPont impact tester in accordance with JIS K 7124. The test was carried out at both 23°C and -20°C.

[0074] In the test at -20°C, the fractured area was visually inspected to determine whether it was ductile or brittle fracture. Evaluation was based on the following criteria.

[0075] ◎: Ductile fracture, 〇: Ductile fracture, △: Mixed ductile and brittle fracture, × Brittle fracture

[0076] (Releasability: Vacuum molding cycle test) The releasability was checked and evaluated as follows:

[0077] ◎: Vacuum forming possible with a cycle of 8 seconds or less, 〇: Vacuum forming possible with a cycle of 10 seconds (release was OK), △: Poor release sometimes occurred with a 10-second cycle.

[0078] (Tray deformation after microwave cooking) The tray was filled with salad oil up to about 15 mm from the bottom, and cooked in a 600W microwave oven up to 160°C while measuring the temperature with a fiber optic thermometer. The degree of deformation was then evaluated visually.

[0079] ◯: No warping or deformation was visible to the naked eye; △: Slight warping, deformation, and surface melting was visible to the naked eye; ×: Significant deformation was observed.

[0080] The results are shown in Table 2.

[0081] [Table 2]

[0082] In the examples, ductile fracture tended to occur when fractured at -20°C, whereas in the comparative examples, brittle fracture tended to occur.

[0083] Furthermore, although no carboxylic acid amide-based release agent was contained, favorable viscosity formation was observed.

[0084] (Laminate: Examples 6 to 8) (Manufacturing of laminated sheets) The first resin composition was fed into a φ40mm extruder heated to 190°C, the second resin composition into a φ50mm extruder heated to 190°C, and the third resin composition into another φ40mm extruder heated to 190°C.The mixture was melt-kneaded with a screw, and then a laminate sheet consisting of a first resin composition layer (thickness 100μm), a second resin composition layer (thickness 300μm), and a third resin composition layer (thickness 100μm) was produced by co-extrusion molding in a T-die heated to 190°C.

[0085] The compositions (parts by mass) of the first resin composition layer and the third resin composition layer were the compositions of the "both outer layer resins" in Table 3, and the composition (parts by mass) of the second resin composition layer was the composition of the intermediate layer resin in Table 3.

[0086] The obtained laminate sheet was vacuum-formed to obtain a tray in the same manner as in Example 1. Evaluation was carried out in the same manner as in Example 1.

[0087] The results are shown in Table 3.

[0088] In Example 6, the intermediate layer had the composition of Example 1 and both outer layers had the composition of Example 2, and the crack evaluation (ductile fracture) in the cold impact test was the same as in Example 1, and the mold release properties were the same as in Example 2.

[0089] In Example 7, the intermediate layer had the composition of Example 1 and both outer layers had the composition of Example 3, and the crack evaluation (ductile fracture) in the cold impact resistance test was the same as in Example 2, and the mold release properties from the mold were the same as in Example 2.

[0090] In Example 8, the intermediate layer had the composition of Example 2 and both outer layers had the composition of Example 3, and the crack evaluation (ductile fracture) in the same cold impact resistance test as in Example 2 was performed, and the mold release properties from the mold were similar to those of Example 2.

[0091] [Table 3] [Explanation of symbols]

[0092] 10...first resin composition layer, 20...second resin composition layer, 30...third resin composition layer, 100...laminated body, 200...tray.

Claims

1. The composition comprises polylactic acid, a biodegradable polyester having a melting point of 40 to 125°C and a melting enthalpy ΔH of 0 to 60 J / g, and talc; Does not contain carboxylic acid amides A resin composition that satisfies either of the following requirements A or B. Requirement A: The biodegradable polyester has a melting enthalpy ΔH of 35 J / g or less, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 65 parts by mass, 25 to 45 parts by mass, and 7 to 15 parts by mass, respectively, relative to a total of 100 parts by mass of the polylactic acid, the biodegradable polyester, and the talc, and the parts by mass of the polylactic acid are greater than the parts by mass of the biodegradable polyester. Requirement B: The melting enthalpy ΔH of the biodegradable polyester is greater than 35 J / g and not greater than 60 J / g, and the polylactic acid, biodegradable polyester, and talc are contained in amounts of 45 to 55 parts by mass, 35 to 45 parts by mass, and 7 to 15 parts by mass, respectively, relative to a total of 100 parts by mass of the polylactic acid, the biodegradable polyester, and the talc, and the parts by mass of the polylactic acid are greater than the parts by mass of the biodegradable polyester.

2. The resin composition according to claim 1, which satisfies requirement A.

3. A sheet of the resin composition according to claim 1.

4. A laminate including a first resin composition layer, a second resin composition layer, and a third resin composition layer in this order, the first resin composition layer, the second resin composition layer, and the third resin composition layer each contain polylactic acid, a biodegradable polyester having a melting point of 125°C or less and a melting enthalpy ΔH of 0 to 60 J / g, and talc; In the first resin composition layer, the mass fraction of the biodegradable polyester relative to the total mass of the polylactic acid, the biodegradable polyester, and the talc is defined as X1, and the melting enthalpy of the biodegradable polyester is defined as ΔH1 (J / g), In the second resin composition layer, the mass fraction of the biodegradable polyester relative to the total mass of the polylactic acid, the biodegradable polyester, and the talc is defined as X2, and the melting enthalpy of the biodegradable polyester is defined as ΔH2 (J / g), When the mass fraction of the biodegradable polyester relative to the total mass of the polylactic acid, the biodegradable polyester, and the talc in the third resin composition layer is X3 and the melting enthalpy of the biodegradable polyester is ΔH3 (J / g), X1 / ΔH1<X2 / ΔH2 and X3 / ΔH3<X2 / ΔH2 are satisfied, A laminate, wherein each of the resin compositions of the first resin composition layer, the second resin composition layer, and the third resin composition layer is the resin composition according to claim 1.

5. A thermoformed product of the sheet according to claim 3 or the laminate according to claim 4.

6. The thermoformed article of claim 5 which is a tray.

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