JP2022099905A - Mouthpiece and its manufacturing method - Google Patents

Abstract

To provide a method of manufacturing a mouthpiece that is light in weight due to foaming and that can adequately control liquid leakage.SOLUTION: A method of manufacturing a mouthpiece disclosed herein includes: a process (A) for preparing a molten resin composition containing a resin material and a supercritical fluid; a process (B) for injecting the molten resin composition into a cavity of a mold; a process (C) for foaming the molten resin composition in the cavity by decreasing the pressure; and a process (D) for recovering from the mold a mouthpiece with a plurality of voids originating from the foaming of the molten resin composition. When supercritical nitrogen is used in the process (A), 0.1 to 1.2 pts.mass of nitrogen is added to 100 pts.mass of the resin material. When supercritical carbon dioxide is used in the process (A), 0.8 to 4.2 pts.mass of carbon dioxide is added to 100 pts.mass of the resin material.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a spout and a method for manufacturing the same.

In recent years, plastic molded products have been used in all everyday goods and industrial products around us. Demand for plastic molded products is increasing due to the progress of generalization by improving the quality of plastic molded products and reducing costs. On the other hand, as seen in the marine plastic waste problem, it has been noticed that microplastics affect environmental pollution, and there is a growing tendency to refrain from the movement to remove plastics and the use of plastic products.

Regarding disposable plastic containers for food and daily necessities, there is a growing demand from users to reduce the amount of petroleum-derived plastic used as much as possible. In response to such demands, efforts are being made to use plant-derived resins as part of the raw materials, to utilize recycled plastic materials, and to reduce the amount of plastic used by devising dimensions and shapes.

Effervescent molding is known as a means for reducing the weight of plastic molded products. Foam molding can be roughly divided into chemical foam molding and physical foam molding. A foaming agent is used in chemical foam molding. 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 problems such as concern about the adverse effect of the foaming agent on the environment and contamination of the mold. Conventionally, supercritical fluid molding has been applied to relatively large industrial products such as automobile parts molding and office equipment. In recent years, with the improvement of the technique for producing a supercritical fluid and the technique for kneading a resin composition, it has been studied to apply supercritical fluid molding to high-cycle injection molding. Patent Documents 1 to 3 disclose food containers manufactured by supercritical fluid molding.

Japanese Patent No. 6085729 Japanese Patent No. 6430684 Japanese Unexamined Patent Publication No. 2020-040690

In order to expand the scope of application of supercritical fluid molding, the present inventors have attempted to manufacture a spout of a container containing a liquid substance such as a drink or jelly by supercritical fluid molding. As a result, it was found that as the degree of foaming is increased, the amount of the resin material used can be reduced, but liquid leakage is likely to occur.

The present disclosure provides a spout and a method for manufacturing the same, which are reduced in weight by foaming and can sufficiently suppress liquid leakage.

One aspect of the present disclosure relates to a method of making a spout using a supercritical fluid. The production method according to the first aspect of the present disclosure uses nitrogen in a supercritical state. That is, this manufacturing method includes (A1) a step of preparing a molten resin composition containing a resin material and nitrogen in a supercritical state, and (B1) a step of injecting the molten resin composition into a cavity of a mold. , (C1) The step of foaming the molten resin composition by reducing the pressure in the cavity, and (D1) the step of recovering the spout having a plurality of voids derived from the foaming from the mold, the molten resin composition. When the mass of the resin material in the object is 100 parts by mass, the amount of nitrogen in the supercritical state is 0.1 to 1.2 parts by mass.

According to the above-mentioned production method, when the amount of nitrogen in the molten resin composition is within the above range, both the weight reduction of the spout and the suppression of liquid leakage can be sufficiently achieved. According to the study by the present inventors, when the amount of nitrogen in the molten resin composition exceeds 1.2 parts by mass, a pattern recognized as an irregular flow of the resin material appears on the surface of the spout, and in particular, The tip of the mouth tends to be uneven. This unevenness is presumed to be one of the causes of liquid leakage.

Instead of nitrogen in the supercritical state, carbon dioxide in the supercritical state may be used. That is, the production method according to the second aspect of the present disclosure includes a step of preparing a molten resin composition containing (A2) a resin material and carbon dioxide in a supercritical state, and (B2) a molten resin composition of gold. The step of injecting into the cavity of the mold, (C2) the step of foaming the molten resin composition by reducing the pressure in the cavity, and (D2) the step of recovering the spout having a plurality of voids derived from the foaming from the mold. When the mass of the resin material in the molten resin composition is 100 parts by mass, the amount of carbon dioxide in the supercritical state is 0.8 to 4.2 parts by mass.

According to the above-mentioned production method, when the amount of carbon dioxide in the molten resin composition is within the above range, both the weight reduction of the spout and the suppression of liquid leakage can be sufficiently achieved. According to the study by the present inventors, when the amount of carbon dioxide in the molten resin composition exceeds 4.2 parts by mass, a pattern recognized as a trace of irregular flow of the resin material appears on the surface of the spout, and at the same time, In particular, the tip of the mouth tends to be uneven. This unevenness is presumed to be one of the causes of liquid leakage.

One aspect of the present disclosure relates to a spout that constitutes a container together with the container body. This spout includes a foamed layer having a fused portion having a surface to which the container body is heat-sealed, and a mouth portion having a threaded portion formed on the outer periphery thereof, and having voids derived from a supercritical fluid.

From the viewpoint of the mechanical strength of the spout, it is preferable that a plurality of voids are independent of each other in the foam layer. Further, it is preferable that the spout is provided with a foam layer having an area ratio of voids obtained by cross-sectional observation of 25% or less. When this area ratio is 25% or less, sufficient mechanical strength of the spout can be ensured and liquid leakage can be suppressed to a higher degree.

According to the present disclosure, there is provided a spout and a method for manufacturing the same, which are reduced in weight by foaming and can sufficiently suppress liquid leakage.

FIG. 1 is a cross-sectional view showing a spout according to an embodiment of the present disclosure. FIG. 2 is a front view schematically showing an example of a spout container provided with the spout shown in FIG. 1. FIG. 3 is a cross-sectional view showing a spout according to another embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing a spout according to another embodiment of the present disclosure. FIG. 5 is a perspective view schematically showing an example of a container provided with a spout according to another embodiment of the present disclosure. FIG. 6 is a cross-sectional view schematically showing a spout included in the container shown in FIG. FIG. 7 is a CT image of the mouth plug according to Comparative Example 1. 8 (a) to 8 (c) are CT images of the mouth plug according to Examples 1 and 2 and Comparative Example 2. 9 (a) to 9 (c) are CT images of the mouth plug according to Examples 3 and 4 and Comparative Example 3.

Hereinafter, embodiments of the present disclosure will be described in detail. The present invention is not limited to the following embodiments.

<Manufacturing method of mouth plug>
The method for manufacturing a spout according to the present 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 the molten resin composition into the cavity of the mold.
(C) A step of foaming the molten resin composition in the cavity by reducing the pressure.
(D) A step of recovering a spout having a plurality of voids derived from foaming of a molten resin composition from a mold.
The series of steps from (A) to (D) can be carried out using, for example, a MuCell injection molding machine (“MuCell” is a registered trademark of Trexel. Co. Ltd) (see Patent Documents 1 and 2).

[Step (A)]
First, a molten resin composition containing a resin material and nitrogen or carbon dioxide in a supercritical state is prepared. Examples of the resin material include polypropylene resin and polyethylene resin. According to the study by the present inventors, when nitrogen is used, a molten resin composition is prepared by adding 0.1 to 1.2 parts by mass of nitrogen in a supercritical state to 100 parts by mass of the resin material. When the amount of nitrogen is 0.1 part by mass or more, the weight of the spout can be reduced by foaming. On the other hand, when the amount of nitrogen is 1.2 parts by mass or less, liquid leakage can be sufficiently suppressed. The lower limit of the amount of nitrogen is preferably 0.15 parts by mass, more preferably 0.2 parts by mass, from the viewpoint of weight reduction of the spout. The upper limit of the amount of nitrogen is preferably 0.75 parts by mass, more preferably 0.55 parts by mass, from the viewpoint of suppressing liquid leakage to a higher degree and improving the mechanical strength of the spout. ..

When carbon dioxide is used, 0.8 to 4.2 parts by mass of carbon dioxide in a supercritical state is added to 100 parts by mass of the resin material to prepare a molten resin composition. When the amount of carbon dioxide is 0.8 parts by mass or more, the weight of the spout can be reduced by foaming. On the other hand, when the amount of carbon dioxide is 4.2 parts by mass or less, liquid leakage can be sufficiently suppressed. The lower limit of the amount of carbon dioxide is preferably 1.0 part by mass, more preferably 1.2 parts by mass, from the viewpoint of weight reduction of the spout. The upper limit of the amount of carbon dioxide is preferably 2.8 parts by mass, more preferably 1.7 parts by mass, from the viewpoint of suppressing liquid leakage to a higher degree and improving the mechanical strength of the spout. be.

As described above, nitrogen or carbon dioxide can be used as the supercritical fluid. According to the studies by the present inventors, it is preferable to use nitrogen as the supercritical fluid rather than carbon dioxide from the viewpoint of improving foamability.

When the resin material used is polypropylene resin, the temperature of the molten resin composition (screw cylinder temperature) is preferably about 210 to 230 ° C. When the resin material used is polyethylene resin, this temperature is preferably about 220 to 240 ° C. When this temperature is at least the lower limit value, the resin tends to flow easily in the cavity, while when it is at least the upper limit value, for example, the scorching of the resin tends to be suppressed.

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, and the like, if necessary.

[Step (B) and Step (C)]
(A) The molten resin composition prepared in the step is injected into the cavity through the gate of the mold. When the molten resin composition is introduced into the cavity, the bubble cells grow due to the decrease in pressure and independent bubbles are generated in the resin composition. The injection speed is preferably 5 to 100 mm / sec, more preferably 10 to 30 mm / sec. When the injection speed is 5 mm / sec or more, it is easy for the resin to reach the end of the flow, and the occurrence of short shots tends to be suppressed. On the other hand, when the injection speed is 100 mm / sec or less, it tends to be possible to suppress the formation of sparse air bubbles in the molded body and the formation of irregularities on the surface of the molded body. According to the studies by the present inventors, when the resin material is polyethylene resin and the supercritical fluid is nitrogen, the injection speed in the step (B) is preferably 20 to 40 mm / sec, preferably 25 to 35 mm / sec. Is more preferable. When the resin material is polyethylene resin and the supercritical fluid is carbon dioxide, the injection speed in the step (B) is preferably 20 to 40 mm / sec, more preferably 25 to 35 mm / sec.

According to the study by the present inventors, when the spout to be produced has a thick portion and a thin portion, foaming due to the supercritical fluid mainly occurs in the thick portion, while foaming is suppressed in the thin portion. To. Therefore, the weight of the spout as a whole can be reduced by foaming, and sufficient strength can be maintained for the thin-walled portion. When the molten resin composition is introduced into the cavity through the gate, it foams due to the decrease in pressure. In normal injection molding, a step of applying pressure to the inside of the cavity (holding pressure) is performed after filling the resin, whereas in the above manufacturing method, for example, this step of applying pressure is not performed or the pressure is lower than the filling peak pressure. Foaming occurs in the thick part by applying. It is presumed that the main reason why foaming is suppressed in the thin-walled portion is that the resin is cooled and solidified before foaming occurs in the thin-walled portion.

As described above, from the viewpoint of sufficiently promoting foaming in the thick portion of the spout, it is not necessary to carry out a step (holding pressure) of applying pressure to the cavity after filling the cavity with the molten resin composition. On the other hand, from the viewpoint of suppressing foaming in the thin portion of the spout, it is preferable not to carry out a step called "core back" for reducing the pressure in the cavity. The core back is a step of moving the movable part of the mold to expand the volume of the cabidi before the molten resin filled in the cabidi is solidified (see Patent Document 1). In the present embodiment, as described above, the pressure drop accompanying the introduction of the molten resin composition into the cavity can cause foaming in the region corresponding to the thick portion in the cavity, while the thin portion can be foamed. Foaming in the corresponding region can be suppressed.

[Step (D)]
When the temperature of the spout drops to about 30 to 60 ° C., the spout is collected from the mold. By forming voids derived from foaming inside the spout, weight reduction is achieved and the amount of plastic material used is reduced. Since the voids are formed, it is preferable that the weight is reduced by 5% by mass or more as compared with the molded article (ordinary injection molded article) in which the voids are not formed.

<Mouth plug>
The spout 5 shown in FIG. 1 is manufactured through the above steps. The spout 5 includes a fused portion 1, a mouth portion 2, and a plurality of plates 3. The fused portion 1 has a surface 1a to which the container body 8 (see FIG. 2) is heat-sealed. The mouth portion 2 has a screw portion 2a formed on the outer periphery thereof, and a cap 6 (see FIG. 2) is attached to the mouth portion 2. The plurality of plates 3 are provided so as to extend laterally between the fused portion 1 and the mouth portion 2. The plate 3 is used for transporting and positioning the spout 5 or the spout container 10 in the manufacturing process of the spout container 10 shown in FIG. 2, the filling process of the liquid material, and the like.

The spout 5 includes a foam layer 5a having voids derived from nitrogen or carbon dioxide in a supercritical state. The surface of the spout 5 is preferably composed of the skin layer 5b. It is preferable that the skin layer 5b does not have appearance defects such as minute irregularities (dimples) and foam marks (swirl marks). In the spout 5, the portion having a wall thickness of about 1.5 to 8 mm corresponds to the thick portion. Specifically, the fused portion 1 corresponds to a thick portion. On the other hand, in the spout 5, the portion having a wall thickness of about 0.8 to 0.9 mm corresponds to the thin portion. Specifically, the tip of the mouth portion 2 and the plate 3 correspond to the thin-walled portion.

As shown in FIG. 1, in the present embodiment, the foamed layer 5a is formed in the fused portion 1. In the foamed layer 5a, it is preferable that the voids caused by foaming are independent of each other. On the other hand, if the plurality of voids are not independent and are integrated, the strength of the spout 5 tends to be insufficient. When nitrogen is used as the supercritical fluid, the diameter of the voids existing independently of each other in the foamed layer 5a is about 0.6 to 1.0 mm. On the other hand, when carbon dioxide is used as the supercritical fluid, the diameter of the voids existing independently of each other in the foamed layer 5a is about 1.2 to 1.8 mm. It should be noted that the voids are not formed in the region other than the thick portion of the spout 5, for example, fine voids having an average diameter of about 1 to 50 μm are formed.

The area ratio of the voids in the foam layer 5a is preferably 25% or less. When this area ratio is 25% or less, sufficient mechanical strength of the spout can be ensured and liquid leakage can be suppressed to a higher degree. On the other hand, when this area ratio is 15% or more, it is possible to further reduce the weight of the spout. This area ratio can be obtained from the cross-sectional image obtained by CT scan.

<Spout container>
The spout container 10 includes a spout 5, a cap 6, and a container body 8. The cap 6 has a screw portion formed on the inner surface and is configured to be attached to the mouth portion 2. The container body 8 is made of a flexible packaging material. The inner surface of the container body 8 is made of a resin having a heat-sealing property, and is heat-sealed to the surface 1a of the fusion-bonded portion 1.

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 embodiment, the spout 5 having the configuration shown in FIG. 1 has been exemplified, but the spout may have the configuration shown in FIG. The spout 15 shown in FIG. 3 further includes a straw portion 4 extending from the fused portion 1 in a direction opposite to the mouth portion 2.

Further, the spout may have the configuration shown in FIG. The spout 25 shown in FIG. 4 has two rods 21 and 22 extending in parallel from the fused portion 1 in the direction opposite to the mouth portion 2, and the first and second connecting portions thereof. The portions 23a and 23b are provided. The first connecting portion 23a connects the tip portions of the two rods 21 and 22. The second connecting portion 23b is provided in the vicinity of the first connecting portion 23a on the fusion portion 1 side in parallel with the first connecting portion 23a. The distance between the first connecting portion 23a and the second connecting portion 23b may be about 8 to 20 mm. It should be noted that these configurations of the spout 25 are for facilitating the flow of the liquid into the mouth 2 by forming a gap in the spout container even when the liquid in the spout container is low. The wall thickness of the second connecting portion 23b is about 1.5 to 2 mm, which corresponds to the thick wall portion.

In the above embodiment, the spout container is exemplified, but the spout according to the present disclosure may be in a form applicable to other containers. FIG. 5 is a perspective view schematically showing an example of a container provided with a spout according to the present disclosure. The container 30 shown in this figure is for sale in a state of containing, for example, juice, soy sauce or liquor. The container 30 includes a container body 38, a spout 35, and a cap 36. As shown in FIG. 6, the spout 35 includes a fusing portion 31 having a surface 31a to which the container body 38 is heat-sealed, and a mouth portion 32 having a threaded portion 32a formed on the outer periphery thereof.

Hereinafter, the present disclosure will be described with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(Comparative Example 1)
Using the following materials, ordinary injection molding was used to prepare spouts (10 in total) having the configuration shown in FIG. FIG. 7 is a cross-sectional image of the mouth plug according to Comparative Example 1 by CT scan.
[Resin material]
・ High-density polyethylene (manufactured by Prime Polymer Co., Ltd., 2100K (trade name))
[Colorant (masterbatch)]
・ PEMSSCMF0291 White (manufactured by Dainichiseika Co., Ltd.)
[Mouth plug configuration]
・ Inner diameter of mouth: 8.7 mm
・ Outer diameter of mouth: 10.6 mm
-Maximum wall thickness of fused part: 7.8 mm
-Space between two rods 21 and 22 (see Fig. 4): 14 mm
-Maximum wall thickness of the first connecting portion 23a (see FIG. 4): 1.5 mm
-Maximum wall thickness of the second connecting portion 23b (see FIG. 4): 2 mm
・ Weight: 3.00g

(Example 1)
A molten resin composition was prepared by adding 0.5 parts by mass of nitrogen in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, spouts (10 in total) having the same shape as in Comparative Example 1 were produced. The injection speed was 30 mm / sec. The weight of the spout according to Example 1 was 2.82 g, and a weight reduction rate of 6.0% was achieved based on Comparative Example 1. 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.

FIG. 8A is a cross-sectional image of the spout according to Example 1 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1, and voids (diameter: about 0.6 to 1.0 mm) independent of each other were formed in the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained. The results are shown in Table 1. The area ratio of the void is the ratio of the area of the void in the second connecting portion (the area of the portion displayed in black in the cross-sectional image) to the cross-sectional area of the second connecting portion.

(Example 2)
A molten resin composition was prepared by adding 1.0 part by mass of nitrogen in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, spout plugs (10 in total) were produced in the same manner as in Example 1. The weight of the spout according to Example 2 was 2.79 g, and a weight reduction rate of 7.0% was achieved based on Comparative Example 1.

FIG. 8B is a cross-sectional image of the spout according to Example 2 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1 and the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A molten resin composition was prepared by adding 2.0 parts by mass of nitrogen in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, spout plugs (10 in total) were produced in the same manner as in Example 1. The weight of the spout according to Comparative Example 2 was 2.73 g, and a weight reduction rate of 9.0% was achieved based on Comparative Example 1.

FIG. 8 (c) is a cross-sectional image of the mouth plug according to Comparative Example 2 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1 and the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
A molten resin composition was prepared by adding 1.5 parts by mass of carbon dioxide in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, a spout having the same shape as that of Comparative Example 1 was produced. The injection speed was 30 mm / sec. The weight of the spout according to Example 3 was 2.83 g, and a weight reduction rate of 5.7% was achieved based on Comparative Example 1.

FIG. 9A is a cross-sectional image of the spout according to Example 3 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1, and voids (diameter: about 1.2 to 1.8 mm) independent of each other were formed in the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained in the same manner as in Example 1. The results are shown in Table 2.

(Example 4)
A molten resin composition was prepared by adding 3.0 parts by mass of carbon dioxide in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, a spout was prepared in the same manner as in Example 1. The weight of the spout according to Example 4 was 2.81 g, and a weight reduction rate of 6.3% was achieved based on Comparative Example 1.

FIG. 9B is a cross-sectional image of the spout according to Example 4 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1 and the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 3)
A molten resin composition was prepared by adding 6.0 parts by mass of carbon dioxide in a supercritical state to 100 parts by mass of the resin material. Using this molten resin composition, a spout was prepared in the same manner as in Example 1. The weight of the spout according to Comparative Example 3 was 2.79 g, and a weight reduction rate of 7.0% was achieved based on Comparative Example 1.

FIG. 9C is a cross-sectional image of the mouth plug according to Comparative Example 3 by CT scan. As shown in this cross-sectional image, visible voids were formed in the fused portion 1 and the second connecting portion 23. From the cross-sectional image, the number of voids and the area ratio of the voids in the second connecting portion 23b were obtained in the same manner as in Example 1. The results are shown in Table 2.

<Evaluation of liquid leakage>
Spout containers were prepared using the spouts according to Examples and Comparative Examples, respectively. The cap was manufactured by ordinary injection molding. The mouth of the spout was closed with a cap and the penetrant was injected into the mouth. The cap was installed upside down so that it was on the lower side, and after 24 hours, it was confirmed whether or not liquid leakage was observed between the mouth and the cap. For each of Examples and Comparative Examples, 10 spout containers were prepared and evaluated. Tables 1 and 2 show the number of spout containers in which liquid leakage occurred (number of liquid leakage occurrences) among the 10 spout containers.

1,31 ... Fusion part, 1a, 31a ... Surface, 2,32 ... Mouth part, 2a, 32a ... Screw part, 3 ... Plate, 4 ... Straw part, 5,15,25,35 ... Foam layer, 5b ... skin layer, 6,36 ... cap, 8,38 ... container body, 10 ... spout container, 21,22 ... rod, 23a ... first connecting part, 23b ... second connecting part, 30 ... container

Claims (6)

(A1) A step of preparing a molten resin composition containing a resin material and nitrogen in a supercritical state, and
(B1) A step of injecting the molten resin composition into the cavity of the mold, and
(C1) A step of foaming the molten resin composition by reducing the pressure in the cavity.
(D1) A step of recovering a spout having a plurality of voids derived from the foam from the mold.
Including
A method for producing a spout, wherein the amount of nitrogen in the supercritical state is 0.1 to 1.2 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass. (A2) A step of preparing a molten resin composition containing a resin material and carbon dioxide in a supercritical state, and
(B2) A step of injecting the molten resin composition into the cavity of the mold, and
(C2) A step of foaming the molten resin composition by reducing the pressure in the cavity.
(D2) A step of recovering a spout having a plurality of voids derived from the foam from the mold.
Including
A method for producing a spout, wherein the amount of carbon dioxide in the supercritical state is 0.8 to 4.2 parts by mass when the mass of the resin material in the molten resin composition is 100 parts by mass. A spout that constitutes a container together with the container body.
A fusion part having a surface to which the container body is heat-sealed,
The mouth part where the screw part is formed on the outer circumference and the mouth part
Equipped with
A spout containing a foam layer with voids derived from a supercritical fluid. The mouth plug according to claim 3, further comprising a straw portion extending from the fused portion in a direction opposite to the mouth portion. The spout according to claim 3 or 4, wherein in the foam layer, the plurality of voids are independent of each other. The spout according to any one of claims 3 to 5, wherein the foamed layer has an area ratio of voids obtained by cross-sectional observation of 25% or less.

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