Container manufacturing method

Abstract

To provide a manufacturing method for containers that can reduce the amount of plastic used and is useful for manufacturing thin-walled containers that are prone to short shots in conventional manufacturing methods with high yields.SOLUTION: The method for manufacturing a container according to the present disclosure includes the processes of (A1) preparing a molten resin composition including a resin material and carbon dioxide in a supercritical state, (B1) injecting the molten resin composition into a cavity of a mold, (C1) after the above (B1) process, maintaining pressure in the cavity under a pressure condition of 15 to 80 MPa and cooling the cavity, and (D1) collecting a container having a thin-walled portion of 0.6 mm or less in thickness from the mold, and the amount of carbon dioxide in a supercritical state is 2 to 3 pts.mass when the mass of the resin material in the molten resin composition is 100 pts.mass.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a container and a manufacturing method thereof, and more particularly to a thin-walled container manufactured by supercritical fluid molding and a manufacturing method thereof. [Background technology]

[0002] In recent years, the impact of microplastics on the global environment has been attracting attention, and there has been a growing trend to move away from plastic and to refrain from using plastic products. With regard to disposable plastic containers for food and daily necessities, there has been a growing demand from users to reduce the amount of petroleum-derived plastic used, even if only a little.

[0003] One of the means to reduce the amount of plastic used is foam molding. Foam molding can be broadly divided into chemical foam molding and physical foam molding. In chemical foam molding, a foaming agent is used. On the other hand, in physical foam molding, a fluid in a supercritical state is used, and this method is called supercritical fluid molding. Chemical foam molding has concerns about the negative impact of the foaming agent on the environment and issues such as mold contamination. Supercritical fluid molding has traditionally been applied to relatively large industrial products such as automobile part molding and office equipment. In recent years, with the improvement of supercritical fluid generation technology and resin composition kneading technology, the application of supercritical fluid molding to high-cycle injection molding has been considered. Patent Documents 1 to 3 disclose food containers manufactured by supercritical fluid molding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6085729 [Patent Document 2] Patent No. 6430684 [Patent Document 3] JP 2020-040690 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to broaden the scope of application of supercritical fluid molding, the present inventors attempted to use supercritical fluid molding to manufacture thin-walled containers for storing butter, margarine, cream cheese, etc. As a result, the present inventors discovered that while supercritical fluid molding can reduce the amount of resin material used, it also poses the problem of the phenomenon in which the resin material does not reach the flow end of the cavity (hereinafter referred to as "short shot").

[0006] The present disclosure has been made to solve the above problems, and provides a method for manufacturing a container that can reduce the amount of plastic used and is useful for manufacturing thin-walled containers that are prone to short shots in conventional manufacturing methods with a high yield. The present disclosure also provides a container that uses a reduced amount of plastic and is applicable to thin-walled containers for storing dairy products such as butter and margarine. [Means for solving the problem]

[0007] One aspect of the present disclosure relates to a method for producing a thin-walled container using a supercritical fluid. The production method according to the first aspect of the present disclosure uses carbon dioxide in a supercritical state. That is, this production method includes the steps of (A1) preparing a molten resin composition containing a resin material and carbon dioxide in a supercritical state, (B1) injecting the molten resin composition into a cavity of a mold, (C1) after the step (B1), maintaining the cavity at a pressure of 15 to 80 MPa and cooling it, and (D1) recovering a container having a thin-walled portion with a thickness of 0.6 mm or less from the mold, in which the amount of carbon dioxide in a supercritical state is 2 to 3 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass.

[0008] According to the above-mentioned manufacturing method, by setting the amount of carbon dioxide in the molten resin composition within the above-mentioned range and the pressure holding condition in step (C1) within the above-mentioned range, a lightweight thin-walled container can be obtained with a high yield. According to the study by the present inventors, for example, when the amount of carbon dioxide in the molten resin composition is less than 2 parts by mass, short shots are likely to occur. Furthermore, when the pressure holding condition in step (C1) exceeds 80 MPa, after-swelling is likely to occur significantly. After-swelling refers to a phenomenon in which a molded body swells locally after being removed from a mold, and is presumed to occur easily at locations where distortion is concentrated due to residual stress during cure shrinkage after molding.

[0009] Instead of carbon dioxide in a supercritical state, nitrogen in a supercritical state may be used. That is, the manufacturing method according to the second aspect of the present disclosure includes (A2) a step of preparing a molten resin composition containing a resin material and nitrogen in a supercritical state, (B2) a step of injecting the molten resin composition into a cavity of a mold, (C2) a step of cooling the cavity while maintaining the pressure of the cavity at a pressure condition of 5 to 50 MPa after the step (B2), and (D2) a step of recovering a container having a thin-walled part with a thickness of 0.6 mm or less from the mold, in which the amount of nitrogen in a supercritical state is 0.5 to 1.5 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass.

[0010] According to the above-mentioned production method, since the amount of nitrogen in the molten resin composition is within the above-mentioned range and the pressure-holding conditions in step (C2) are within the above-mentioned range, a lightweight thin-walled container can be obtained with a high yield.

[0011] One aspect of the present disclosure relates to a container that is a molded body produced by supercritical fluid molding. The container has a bottom having a thickness of 0.3 to 0.6 mm and a side wall having a thickness of 0.25 to 0.40 mm. The container uses less plastic and is applicable to thin-walled containers that store dairy products such as butter and margarine. The container is also applicable to thin-walled containers that store desserts such as parfait ice cream, pudding, shaved ice, and yogurt. Effect of the Invention

[0012] According to the present disclosure, a method for manufacturing a container is provided that can reduce the amount of plastic used and is useful for manufacturing thin-walled containers that are prone to short shots in conventional manufacturing methods with a high yield. Also, according to the present disclosure, a container is provided that reduces the amount of plastic used and is applicable to thin-walled containers for storing dairy products such as butter and margarine. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a container according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the bottom and side wall of the container shown in FIG. [Diagram 3] FIG. 3(a) is a photograph showing the container according to Comparative Example 1, and FIG. 3(b) is a photograph showing the container according to Example 1. [Figure 4] FIG. 4 is a photograph showing the container according to Comparative Example 3. [Diagram 5] FIG. 5(a) is a photograph showing the container according to Comparative Example 4, and FIG. 5(b) is a photograph showing the container according to Comparative Example 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present invention is not limited to the following embodiments.

[0015] <Container manufacturing method> The method for manufacturing a container according to this embodiment includes the following steps. (A) A step of preparing a molten resin composition containing a resin material and a supercritical fluid. (B) A step of injecting a molten resin composition into a cavity of a mold. (C) A process for maintaining pressure in the cavity and cooling it after the process (B) above. (D) A process of recovering the container having a thin-walled portion having a thickness of 0.6 mm or less from the mold. A series of steps from step (A) to step (D) can be carried out, for example, using a MuCell injection molding machine ("MuCell" is a registered trademark of Trexel Co. Ltd.) (see Patent Documents 1 and 2).

[0016] [(A) Process] First, a molten resin composition containing a resin material and a supercritical fluid is prepared. Examples of the resin material include thermoplastic resins, and specific examples thereof are polypropylene resin and polyethylene resin. The melt flow rate of the thermoplastic resin is preferably 15 g / 10 min or more, more preferably 20 to 40 g / 10 min, and even more preferably 25 to 36 g / 10 min. When this value is 15 g / 10 min or more, the occurrence of short shots tends to be suppressed, while when it is 40 g / 10 min or less, a container with excellent drop resistance tends to be manufactured. The melt flow rate (MFR) here means a value measured under conditions of a temperature of 230° C. and a load of 2.16 kg in accordance with the method described in JIS K7210-1:2014.

[0017] According to the study by the present inventors, when carbon dioxide is used, 2 to 3 parts by mass of carbon dioxide in a supercritical state is added to 100 parts by mass of the resin material to prepare the molten resin composition. When the amount of carbon dioxide is 2 parts by mass or more, the variation in the filling pressure for each molding shot can be reduced, and the occurrence of short shots can be suppressed by the decrease in viscosity of the molten resin composition due to the addition of carbon dioxide. In addition, voids can be formed inside the molded body by promoting foaming caused by carbon dioxide in a supercritical state. On the other hand, when the amount of carbon dioxide is 3 parts by mass or less, the dwell pressure in step (C) can be set relatively low, and there is a tendency that post-blistering can be suppressed.

[0018] When nitrogen is used, 0.5 to 1.5 parts by mass of carbon dioxide in a supercritical state is added to 100 parts by mass of the resin material to prepare the molten resin composition. When the amount of nitrogen is 0.5 parts by mass or more, the variation in the filling pressure for each molding shot can be reduced, and the addition of nitrogen reduces the viscosity of the molten resin composition, thereby suppressing the occurrence of short shots. In addition, by promoting foaming caused by nitrogen in a supercritical state, voids can be formed inside the molded body. On the other hand, when the amount of nitrogen is 1.5 parts by mass or less, the pressure of the dwell pressure in step (C) can be set relatively low, which tends to suppress post-blistering.

[0019] The temperature of the molten resin composition (screw cylinder temperature) may be set according to the melting point or MFR of the resin material. When a polypropylene resin is used, this temperature is preferably about 210 to 230°C. When a polyethylene resin is used, this temperature is preferably about 220 to 240°C. When this temperature is equal to or higher than the lower limit, the resin easily flows in the cavity, while when the temperature is equal to or lower than the upper limit, the resin tends to be prevented from burning.

[0020] The molten resin composition may contain components other than the resin material and the supercritical fluid, that is, the molten resin composition may further contain, for example, a filler, a colorant, a slip agent, an antistatic agent, etc., as necessary.

[0021] [(B) Process] The molten resin composition prepared in the step (A) is injected into the cavity through the gate of the mold. The injection speed is preferably 60 mm / sec or more, more preferably 200 mm / sec or more, and even more preferably 250 mm / sec or more. By making the injection speed 60 mm / sec or more, the resin tends to easily reach the end of the flow, and the occurrence of short shots tends to be suppressed. The upper limit of the injection speed is, for example, 350 mm / sec.

[0022] Even if the distance from the cavity gate to the farthest flow end (hereinafter referred to as the "maximum flow length") is 60 mm or more, it is preferable that the molten resin composition reaches the flow end. The maximum flow length may be, for example, 70 mm or more or 80 mm or more. The upper limit of the maximum flow length is, for example, 120 mm.

[0023] [(C) Process] After the above step (B), the cavity is cooled while being held under pressure. According to the study by the present inventors, when carbon dioxide is used as the supercritical fluid, the pressure is held under a pressure condition of 15 to 80 MPa. When this pressure is 15 MPa or more, the occurrence of short shots can be suppressed, while when it is 80 MPa or less, the occurrence of after-swelling tends to be suppressed. This value is preferably 15 to 50 MPa, and more preferably 15 to 30 MPa. When nitrogen is used as the supercritical fluid, the pressure is held under a pressure condition of 5 to 50 MPa. When this pressure is 5 MPa or more, the occurrence of short shots can be suppressed, while when it is 50 MPa or less, the occurrence of after-swelling tends to be suppressed. This value is preferably 15 to 50 MPa, and more preferably 30 to 50 MPa. The pressure holding time may be, for example, 0.1 to 1.0 seconds, regardless of the type of supercritical fluid.

[0024] From the viewpoint of producing a thin-walled container, it is preferable not to carry out a step called "core-back" for reducing the pressure inside the cavity. Core-back is a step in which the movable part of the mold is moved to expand the volume of the cavity before the molten resin composition filled in the cavity has completely solidified (see Patent Document 1).

[0025] [(D) Process] When the temperature of the molded body (thin-walled container) in the mold falls to about 30 to 60°C, the molded body is removed from the mold. In this embodiment, pressure is maintained in step (C) and "core-back" is not performed as described above, so that large voids that can be visually confirmed are not formed in the container body according to this embodiment. It can be said that the container according to this embodiment is mainly intended to be lightweight by thinning rather than by voids.

[0026] <Container> The container 10 shown in Fig. 1 is manufactured through the above process. In a plan view, the container 10 has a generally rectangular shape with rounded corners. The container 10 includes a bottom 1, a pair of side walls 2a, a pair of side walls 2b, and flanges 3 provided at the four corners. In a plan view, the side walls 2a form the short sides of the container 10, while the side walls 2b form the long sides of the container 10. The flanges 3 serve as a guide for a lid (not shown) that fits into the container 10.

[0027] As shown in Fig. 2, the central portion 1a of the bottom portion 1 corresponds to the gate position of the mold. The bottom portion 1 is formed with feet 5. Providing the feet 5 in the container 10 increases the drop resistance. That is, even if the container 10 is dropped, for example, from a table, the feet 5 can prevent the bottom portion 1 from directly hitting the floor, and damage to the bottom portion 1 and its vicinity can be suppressed.

[0028] The thickness of the bottom 1 is 0.3 to 0.6 mm, and may be 0.4 to 0.5 mm. When the thickness is 0.3 mm or more, rear bulging tends to be suppressed and drop resistance can be ensured. On the other hand, when the thickness is 0.6 mm or less, weight reduction can be achieved. The thickness of the side walls 2a, 2b is 0.25 to 0.4 mm, and may be 0.3 to 0.35 mm. When the thickness is 0.25 mm or more, drop resistance can be ensured. On the other hand, when the thickness is 0.4 mm or less, weight reduction can be achieved.

[0029] The container 10 can be applied to a thin-walled container for storing butter, margarine, cream cheese, etc. In order to mold a thin-walled container by conventional injection molding, it was necessary to select a resin with high fluidity (high MFR value) to prevent short shots. However, since a resin material with high fluidity tends to have a relatively small molecular weight and low strength, it was difficult to manufacture a thin-walled container with excellent drop resistance. In contrast, in this embodiment, even if a resin material with a relatively small MFR value is used, the fluidity of the molten resin composition can be increased by using it in combination with a supercritical fluid. This makes it possible to achieve both excellent short shot suppression and excellent drop resistance. Since the container 10 has excellent drop resistance, it may be relatively large in capacity (for example, internal volume: 280cc or more).

[0030] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiments, carbon dioxide or nitrogen is used as the supercritical fluid, but instead of these gases, for example, argon or helium may be used. EXAMPLES

[0031] The present disclosure will be described below based on examples and comparative examples. Note that the present invention is not limited to the following examples.

[0032] Comparative Example 1 Using the materials listed below, a single container with the structure shown in Figure 1 was produced by normal injection molding (speed control) (see Figure 3(a)). [Resin material] Polypropylene (Prime Polymer Co., Ltd., J667TG (model number), MFR: 36g / 10min) [Molding conditions] Screw cylinder temperature (5 zones): 210~240℃ ·Injection speed: 250mm / sec Filling pressure: 220MPa - Holding pressure: 80MPa Pressure retention time: 0.5 seconds Maximum flow length in cavity: 99mm [Container configuration] Bottom thickness: 0.385mm (target value: 0.350mm) Side wall (short side) thickness: 0.346mm (target value: 0.350mm) Side wall (long side) thickness: 0.359mm (target value: 0.350mm) Flange thickness: 0.355mm (target value: 0.350mm) ·Mass: 10.02g

[0033] Example 1 A molten resin composition was prepared by adding 3.0 parts by mass of supercritical carbon dioxide to 100 parts by mass of a resin material. A container was produced in the same manner as in Comparative Example 1, except that this molten resin composition was used and the filling pressure was set to 190 MPa (see FIG. 3(b)). In this example and the following examples and comparative examples, a MuCell injection molding machine ("MuCell" is a registered trademark of Trexel Co. Ltd.) was used. [Container configuration] Bottom thickness: 0.380mm (target value: 0.350mm) Side wall (short side) thickness: 0.334mm (target value: 0.350mm) Side wall (long side) thickness: 0.350mm (target value: 0.350mm) Flange thickness: 0.345mm (target value: 0.350mm) ·Mass: 9.64g As described above, the mass of the container according to Example 1 was 9.64 g, and a weight loss rate of 3.8% was achieved based on that of Comparative Example 1.

[0034] Comparative Example 2 A container was produced in the same manner as in Comparative Example 1, except that the following polypropylene was used instead of polypropylene (J667TG (model number), MFR: 36 g / 10 min) and the filling pressure was set to 230 MPa. Polypropylene (SunAllomer Co., Ltd., PM970A (model number), MFR: 30g / 10min) [Container configuration] Bottom thickness: 0.395mm (target value: 0.350mm) Side wall (short side) thickness: 0.348mm (target value: 0.350mm) Side wall (long side) thickness: 0.363 mm (target value: 0.350 mm) Flange thickness: 0.363mm (target value: 0.350mm) ·Mass: 10.07g

[0035] Example 2 A molten resin composition was prepared by adding 3.0 parts by mass of supercritical carbon dioxide to 100 parts by mass of a resin material. A container was produced in the same manner as in Comparative Example 2, except that this molten resin composition was used and the filling pressure was set to 200 MPa. [Container configuration] Bottom thickness: 0.384mm (target value: 0.350mm) Side wall (short side) thickness: 0.338mm (target value: 0.350mm) Side wall (long side) thickness: 0.352mm (target value: 0.350mm) Flange thickness: 0.350mm (target value: 0.350mm) ·Mass: 9.62g As described above, the mass of the container according to Example 2 was 9.62 g, and a weight loss rate of 4.4% was achieved based on that of Comparative Example 2.

[0036] Comparative Example 3 A container was produced in the same manner as in Comparative Example 1, except that the following polypropylene was used instead of polypropylene (J667TG (model number), MFR: 36 g / 10 min), and injection molding was performed under pressure control instead of speed control. Polypropylene (Sunallomer Co., Ltd., PM870A (model number), MFR: 17g / 10min) Although the filling pressure was set to 245 MPa or more, short shots occurred (see Figure 4).

[0037] Example 3 A molten resin composition was prepared by adding 3.0 parts by mass of supercritical carbon dioxide to 100 parts by mass of a resin material. A container was produced in the same manner as in Comparative Example 3, except that this molten resin composition was used, injection molding was performed under speed control, and the filling pressure was set to 230 MPa. [Container configuration] Bottom thickness: 0.381mm (target value: 0.350mm) Side wall (short side) thickness: 0.345mm (target value: 0.350mm) Side wall (long side) thickness: 0.359mm (target value: 0.350mm) Flange thickness: 0.350mm (target value: 0.350mm) ·Mass: 9.79g As described above, the mass of the container according to Example 3 was 9.79 g, and a weight reduction rate of 2.1% was achieved based on the design value (10 g) of Comparative Example 3.

[0038] Comparative Example 4 A container was produced in the same manner as in Comparative Example 1, except that the following polypropylene was used instead of polypropylene (J667TG (model number), MFR: 36 g / 10 min), and injection molding was performed under pressure control instead of speed control. Polypropylene (Prime Polymer Co., Ltd., J715M (model number), MFR: 9g / 10min) Although the filling pressure was set to 245 MPa or more, short shots occurred (see Figure 5(a)).

[0039] Comparative Example 5 A molten resin composition was prepared by adding 3.0 parts by mass of supercritical carbon dioxide to 100 parts by mass of a resin material. A container was produced in the same manner as in Comparative Example 4, except that this molten resin composition was used (see FIG. 5(b)). Although the filling pressure was set to 245 MPa or more, a slight short shot was observed in the flange (circled area in FIG. 5(b)).

[0040] Comparative Example 6 A container was produced in the same manner as in Comparative Example 1, except that the following polypropylene was used instead of polypropylene (J667TG (model number), MFR: 36 g / 10 min) and the filling pressure was set to 177 MPa. Polypropylene (SunAllomer, CMA70V (model number), MFR: 48g / 10min) [Container configuration] Bottom thickness: 0.391mm (target value: 0.350mm) Side wall (short side) thickness: 0.350mm (target value: 0.350mm) Side wall (long side) thickness: 0.345mm (target value: 0.350mm) Flange thickness: 0.352mm (target value: 0.350mm) ·Mass: 9.74g

[0041] [Presence or absence of swelling at the back] After being removed from the mold, the presence or absence of rear bulging was confirmed by visually observing the containers according to Comparative Examples 1, 2, 5, and 6 and Examples 1 to 3. Rear bulging was observed at the bottom of all of the containers according to Examples 1 to 3 and Comparative Example 5.

[0042] [Drop resistance rating] The containers according to Comparative Examples 1, 2, and 6 and Examples 1 to 3 were filled with 300 g of margarine. A separately prepared lid (commercially available) was fitted to the container. Thus, a test sample was obtained. The container was dropped three times in succession from a height of 80 cm onto the floor. The sample was dropped so that the bottom surface struck the floor the first time, the side wall (long side) struck the floor the second time, and the side wall (short side) struck the floor the third time. As a result, none of the containers according to Comparative Examples 1 and 2 and Examples 1 to 3 broke or leaked margarine. On the other hand, the container according to Comparative Example 6 broke.

[0043] Table 1 shows the molding conditions in Comparative Examples 1 to 6 and Examples 1 to 3. [Table 1]

[0044] Example 1A A container was produced in the same manner as in Example 1, except that the amount of carbon dioxide was 2.5 parts by mass instead of 3.0 parts by mass. The container could be produced without short shots. While post-swelling occurred in Example 1, post-swelling was not observed in Example 1A.

[0045] (Comparative Example 1A) A container was produced in the same manner as in Example 1, except that the amount of carbon dioxide was 1.5 parts by mass instead of 3.0 parts by mass. A short shot occurred. Note that no after-swelling was observed in Comparative Example 1A.

[0046] Example 1B A container was produced in the same manner as in Example 1, except that the dwell pressure was 30 MPa instead of 80 MPa. A container could be produced without short shots. In addition, the thickness of the bottom could be made closer to the target value (0.35 mm) than in Example 1. In addition, no post-blistering was observed in Example 1B.

[0047] Example 1C A container was produced in the same manner as in Example 1A, except that the dwell pressure was 30 MPa instead of 80 MPa. A container could be produced without short shots. In addition, the thickness of the bottom could be made closer to the target value (0.35 mm) than in Example 1A. In addition, no post-blistering was observed in Example 1C.

[0048] Table 2 shows the molding conditions in Examples 1A to 1C and Comparative Example 1A. [Table 2]

[0049] According to the above embodiment, a thin-walled container with excellent drop resistance was manufactured without short shots. Also, according to the above embodiment, the synergistic effect of thinning the container and foaming allowed a significant reduction in the amount of plastic used compared to conventional containers. Specifically, the container of the above embodiment, which has an overall thickness of about 0.35 mm, weighed about 10 g, whereas a conventional polypropylene container of the same size as the container of the above embodiment except for its overall thickness of 0.6 mm weighed about 14 g. In other words, according to the above embodiment, it was shown that a weight reduction rate of about 30% can be achieved compared to conventional products.

[0050] In addition, the above examples show that it is possible to manufacture thin-walled containers without post-swelling by adjusting the amount of supercritical fluid added and the dwell pressure. It is presumed that post-swelling can also be prevented by selecting the resin material and adjusting the injection conditions. [Explanation of symbols]

[0051] 1...bottom, 1a...central portion, 2a...side wall portion (short side), 2b...side wall portion (long side), 3...flange, 5...foot, 10...container.

Claims

1. (A1) a step of preparing a molten resin composition containing a resin material and carbon dioxide in a supercritical state; (B1) injecting the molten resin composition into a cavity of a mold; (C1) after the (B1) step, a step of maintaining the cavity at a pressure of 15 to 80 MPa and cooling the cavity; (D1) recovering a container having a thin-walled portion with a thickness of 0.6 mm or less from the mold; Including, the amount of the carbon dioxide in a supercritical state is 2 to 3 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass.

2. (A2) preparing a molten resin composition containing a resin material and nitrogen in a supercritical state; (B2) injecting the molten resin composition into a cavity of a mold; (C2) after the (B2) step, a step of maintaining the cavity at a pressure of 5 to 50 MPa and cooling the cavity; (D2) recovering the container having a thin-walled portion having a thickness of 0.6 mm or less from the mold; Including, the amount of the nitrogen in a supercritical state is 0.5 to 1.5 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass.

3. 3. The method for manufacturing a container according to claim 1, wherein the container has a bottom having a thickness of 0.3 to 0.6 mm and a side wall having a thickness of 0.25 to 0.40 mm.

4. The method for manufacturing a container according to any one of claims 1 to 3, wherein a maximum flow length in the cavity is 60 mm or more.

5. The method for manufacturing a container according to any one of claims 1 to 4, wherein the resin material is a thermoplastic resin having a melt flow rate of 15 g / 10 min or more measured under conditions of a temperature of 230°C and a load of 2.16 kg.

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