JPH04173131A - Crystallizing method of mouth part of hollow container and device thereof - Google Patents

Abstract

PURPOSE:To make it possible to enhance the dimensional accuracy of a crystallized mouth part by a method wherein a heat treating vessel, which develops heated atmosphere around the outer wall surface and its top face of a seal forming part, and a heating means, which is arranged at the position opposite to the outer wall surface of the mouth part excluding the seal forming part so as to heat the outer wall surface just mentioned above by radiation, are provided. CONSTITUTION:A screw part 16 and its top face 16a function as seal forming part when a cap is screwed. As the crystallizing device of a mouth part 14, a heat treating vessel 20, which is formed so as to cover the surrounding of the top face 16a of the mouth part 14 and the screw part 16 and the lower end part of which is opened, is provided. The region (a) of the outer surface of the mouth part 14 is one corresponding to the locking ring 18a and the support ring 18b of the mouth part 14 so as to heat the region (a) by radiation heat. A heater 24 is provided on the outer surface 22a of a heating thick walled part 22 opposite to the region (a). The heat capacity of the heating thick walled part 22 heated with the heater 24 is larger than that of the remaining region of the heat treating vessel 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for heating and crystallizing the opening side of a hollow container such as a preform, a final molded container, or an intermediate molded container. In particular, the present invention relates to a method and apparatus for crystallizing the mouth of a hollow container that can satisfy required dimensional accuracy in the crystallized mouth.

[Prior art] When a hollow container is manufactured by biaxial stretch blow molding, either the body has biaxial molecular orientation and has excellent mechanical properties, or the mouth has no molecular orientation and therefore only has mechanical properties. Also, it has poor heat resistance when filling with heat-treated contents for sterilization. Therefore, it is known from Japanese Patent Application Laid-Open No. 88385/1985 to locally heat the mouth portion and then slowly cool it to crystallize it to improve mechanical properties and heat resistance.

Further, as a method of heating the mouth part, a method having a core body inserted into the mouth part in order to regulate the inner diameter dimension of the mouth part during heating is known. ■Unexamined Japanese Patent Publication No. 14-55228 has a core body with high thermal conductivity, ■Unexamined Japanese Patent Application No. 14-55228,
- Japanese Patent Publication No. 88217 discloses a core body that is inserted into the mouth after preheating, and Japanese Patent Publication No. 61-1288 discloses a core body that is heat-shrinkable in the axial direction by providing a concave or convex pattern on the outer surface of the core body in the axial direction. The regulations for each are disclosed.

Furthermore, ■Japanese Patent Application Laid-Open No. 2-6711.9 discloses a system in which local heating of the locking ring and heating of the threaded portion thereon are performed separately, and ■Japanese Patent Application Laid-Open No. 1-56892 discloses It has been disclosed that a core body having a cooling function is inserted into the mouth after heating the mouth to slowly cool the mouth.

[Problems to be Solved by the Invention] After repeated experiments by the inventors of the wood when crystallizing the mouth part, it was found that the seal between the crystallized mouth part and the cap, etc. that is attached after filling the contents was particularly poor. There have been many cases in which molded parts such as threaded parts and their top surfaces are deformed due to heat shrinkage.

To solve these problems, according to the conventional proposals from ■ to ■, the inner diameter of the mouth is regulated by a core body inserted into the mouth.
Only the dimensional accuracy of the inner wall surface of the mouth is maintained. Publication (2) further states that the deformation of the mouth in the axial direction is prevented;
The deformation of the sealing molded portion described above cannot be completely prevented. ■
This proposal only achieves complete crystallization of the mouth regardless of the difference in outer diameter, and does not contribute to achieving the above-mentioned problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for crystallizing the mouth of a hollow container, which can further improve the dimensional accuracy of the crystallized mouth and realize a mouth with a high sealing effect. There is a particular thing.

[Means for Solving the Problems] The method of the present invention has a mouth portion provided with a seal molding portion on the opening side of a hollow container, and in crystallizing the molded resin of the mouth portion, the method includes the steps of: The heating temperature of the outer wall surface of the opening portion is set lower than the heating temperature of the other outer wall surface of the mouth portion.

The apparatus of the present invention for carrying out this method includes: a heat treatment container that creates a hot atmosphere around at least the outer wall surface of the seal forming section and its top surface; and a heat treatment container placed at a position facing the outer wall surface of the mouth portion other than the seal forming section. , and heating means for radiant heating the outer wall surface.

The present invention provides an improved device for crystallizing molded resin in the mouth by heating the outer wall surface of the mouth while inserting a core body into the mouth, which has a mouth on the opening side of the hollow container. In the device, an air release path for releasing air between the outer wall surface of the core body and the inner wall surface of the mouth part, or an air release path for releasing air inside the hollow container to the outside, is formed in the core body. There is.

Similarly, in the device of the present invention, which is an improved device for inserting a core body into a mouth, the inner wall surface of the mouth is heated to a predetermined temperature in the range of 100 to 180°C. It has one built-in heating stage.

[Function] One of the problems addressed by the present inventors is to ensure high accuracy of the seal forming part, which is composed of the neck part and the top surface of the mouth part. ring,
Since it is thinner than other areas such as the support ring, its heat capacity is small, and by heating it at a lower temperature than the other areas mentioned above, it is possible to prevent excessive temperature rise while providing enough heat to crystallize. This can prevent deformation due to heat shrinkage.

This method can be realized by using a device that only exposes the seal molding part to a hot atmosphere and heats other areas with radiant heat.

In order to improve the device for inserting the core body into the mouth, the present inventors focused on the adverse effects caused by the expanded air remaining in the slight gap between the outer surface of the core body and the inner wall of the mouth, that is, the deformation of the mouth. did. This problem was solved by forming an air release path in the core body to allow the expansion air to escape. Furthermore, since the opening side is sealed by the core body, the expanded air inside the hollow container has no place to escape, which is thought to cause deformation of the mouth. Forming such a release path for the expansion air inside the container in the core body is also useful for preventing deformation of the mouth portion.

Conventionally, the core body inserted into the mouth part does not have a built-in heating means,
Previously, the core body was simply made of a material with good thermal conductivity, or the core body was preheated before insertion, but the core body can regulate the inner diameter by heating from the inner wall side of the mouth, and it is built in the core body. Heating that can maintain a predetermined temperature throughout the heating process enables more uniform heating and contributes to preventing deformation of the mouth. Moreover, if heating is also performed from the outer wall of the mouth part, the heat treatment time leading to crystallization can be shortened.

Each of the above-mentioned crystallization devices revolves and transports a large number of hollow containers along a circumferential path that is approximately one circumference, and rotates the hollow containers during the revolution to perform continuous operation in a relatively small space. Therefore, it is possible to perform crystallization treatment efficiently and uniformly.

[Example] Hereinafter, an example in which the present invention is applied to a method and apparatus for molding a heat-resistant hollow container will be specifically described with reference to the drawings.

In this example, after the preform is molded, the final container, a heat-resistant hollow container, is molded through the following steps: - next blow molding step, heat shrinking step, secondary blow molding.

Such a molding method is disclosed in Japanese Unexamined Patent Publication No. 62-270316 and is well known.

In the above molding method, in one blow molding process, each blow molding is performed at a low and medium temperature compared to the molded container1, and in the previous step, each blow molding is performed at a high and distinct temperature. heat-treated, it has two distinct biaxial crystal orientations, which considerably strengthens the mechanical resistance of the container subjected to severe temperature conditions in the final process.
It is known that heat-resistant hollow containers can be obtained.

The above molding process ensures the heat resistance of the bottomed cylindrical body of the hollow container, but below we will explain the apparatus and method for ensuring the heat resistance of the mouth, which is a feature of the present invention.
This will be explained with reference to FIGS. 1 to 3.

In this embodiment, the heat resistance of the mouth part 14 is improved by crystallizing and whitening the neck part 14 of the primary blow-molded product made of, for example, polyethylene terephthalate. This secondary blow molded product 10 is obtained by biaxially stretching blow molding a preform (not shown) that has been injection molded in advance, and the mouth portion 1 is provided on the opening side of a bottomed cylindrical body portion 2.
It has 4. The mouth part 14 consists of a threaded part 16 formed on the upper side and into which the cap is screwed, and a locking ring 18a and a support ring 1.8b on the lower side, which are used in the injection molding process of the preform. It is pre-molded with high usage precision.

In particular, the threaded part] 6 and its top surface 16a function as a molded part for sealing when the cap is screwed together.
High dimensional accuracy must also be maintained in the final container.

A heat treatment container 20 is provided as a crystallization device for the opening] 4. This heat treatment container 20 has a top surface 16 of the mouth portion 14.
a and the neck portion] 6, and its lower end is open. On this lower end side, a heating thick part 22 is provided at a position facing the locking song 18a, support ring], 8b, and each link 1.8a
, 1.8b. Then, a heater 2 is attached to the outer surface 22a of this thick-walled heating portion 22.
4 is provided. A cooling holding member 26 is provided in close contact with the opening side of the lower end of the heat treatment container 20.

The cooling holding member 26 is in close contact with the opening of the heat treatment container 20 to seal the inside thereof with a predetermined airtightness.
Moreover, a cold water jacket 28 for circulating a cooling medium such as cold water is built-in. For example, the cooling holding member 26 is divided into two parts so as to be openable and closable in the left and right directions in FIG. Above the support ring 18
It is configured to support the lower surface of b. As a result, the next blow-molded product]0 is supported by this cooling holding member 26.

The above configuration is a device for heat-treating the outer wall of the mouth 14, and in this embodiment, a heating core body 30 inserted into the mouth 4 is provided in order to heat-treat the inner wall of the mouth 4. ing. This heating core body 30 is roughly divided into a core material 3 at the center.
2 and a peripheral heating rotating body 36, which is rotatably supported with respect to the core member 32. The core material 32 is provided with a hot water jacket 34 capable of circulating a temperature regulating fluid such as hot water. By circulating hot water within the hot water jacket 34, it becomes possible to heat the inner wall surface of the mouth portion 14 via the core material 32 and the heating rotating body 36.

An air vent 40 is provided on the surface 36a of the heating rotating body 36.
is provided. This air vent 40 is mainly used to release air remaining in a small gap between the surface 36a of the heating rotating body 36 and the inner wall surface of the mouth portion 14. In this embodiment, the air vent 40 is shown in FIG.
As shown in A), vertical grooves 42 are formed in a concave shape along the vertical axis at predetermined intervals in the circumferential direction of the heating rotating body 36. The upper end of this vertical groove 42 is connected to the top surface 1.
6a and communicates with the inside of the heat treatment container 20, and its lower end communicates with the inside of the body 2 of the primary blow-molded product 10. As shown in FIG. 2, a heater controller 50 for controlling the temperature of the heater 24 and a hot water jacket 3 are provided on the upper end side of the heating core body 3G.
Input 34a and outport 34 connected to 4
b is provided.

Next, referring to FIG. 3, a conveying device for the primary blow-molded product 10 in the crystallization apparatus will be described.

In this embodiment, the primary blow-molded product 10 is advanced along a circumferential path, and the mouth portion 14 is crystallized, with approximately the circumference being one cycle. For this purpose, a rotating disk 60 is provided, and a large number of support arms 62 are provided on the periphery of the rotating disk 60 at predetermined intervals in the circumferential direction. It supports the cooling holding member 26, the heat treatment container 20, etc. Further, a rotatable rotating body 64 is provided on the side wall of the rotating disk 60. The rotating bodies 64 are arranged as two rotating bodies 64a and 64b at positions corresponding to the respective support arms 62, and are in rolling contact with the body 12 of the primary blow-molded product 10 supported by the cooling holding member 26. . Further, on the inner surface of the outer wall cover 66 disposed concentrically with the rotating disk 60, a rib 68 is provided which protrudes so as to come into contact with the body 12 of the above-mentioned secondary blow molded product. It is formed over the area excluding the area for importing goods] 0. Therefore, when the rotary disk 60 rotates, the secondary blow-molded product 10 revolves, and during this revolution, the primary blow-molded product 10 comes into contact with the ribs 68.
An autorotation force acts on the two rotating bodies 64a and 64b, and the rotating bodies 64a and 64b rotate while being rotationally guided.

This crystallization apparatus is provided with a carry-in guide 70 and a carry-out guide 74 for carrying in the primary blow-molded product 10,
Each guide 70.74 has a curved portion 72.76 which guides the primary blow-molded product 10 to be moved straight along a circumferential path or from a circumferential path to a straight path. Furthermore, a feeding mechanism 80, 82 is provided for feeding the primary blow molded product 10 step by step along the curved portion 72.degree. 76. The rotational driving force of each of the feeding mechanisms 80.82 is the driving force of a sprocket 84 rotated by a driving source such as a motor, which is transmitted to each feeding mechanism 80.82 via a plurality of chains and sprockets. Both feed mechanisms 80 and 82 are driven synchronously. Note that the primary blow-molded product] 0 population position A on this circumferential path is driven by the closing drive of the cooling holding member 26 and the heating core body 30.
At the exit position B, the cooling holding member 26 is opened and the heating core body 30 is removed. For each of these drives, for example, a cam drive based on the driving force of the rotating disk 60 can be adopted.

Hot water supply/drainage to each heating core body 30, cooling holding member 2
The cold water supply/drainage to the rotating disk 60 and the power supply to the heater controller 50 are carried out along an arm 90 (for example, there are two at the top and bottom) that points from the outside of the rotating disk 60 to the center. It is connected to the central shaft portion 92 of. A large number of sets including a hot water/cold water pipe 94a and a power cable 94b extend radially from the central shaft portion 92 toward various parts of the circumference.

Next, the operation of the apparatus of the above embodiment will be explained.

-Next blow molded product] O is the carry-in guide 70 on the right side in Fig. 3
, and is rotationally guided along the curved portion 72 by the rotational drive of the feeding mechanism 80, and reaches the entrance position A of the circumferential path of the mouth crystallization device. In this position A, the cooling holding member 26 is driven closed, and the support ring 18 b of the secondary blow-molded product 10 is supported by the cooling holding member 26 .

Furthermore, the heating core body 30 is driven downward, and its tip is inserted into the mouth part ]4. At this time, since the rotating disk 60 is rotationally driven, the support arm 6 of the rotating disk 60
2. A: Cooling holding member 26. Together with the heat treatment container 20 and the heating core body 30, the next blow molded product 10
It will be driven to revolve. Due to this revolving drive, −
Next, when the body 12 of the blow-molded product 10 comes into contact with the outer ribs 68, rotational force is applied by the ribs 68,
Since it is in rolling contact with the two rotating bodies 64a and 64b, the secondary blow molded product 10 is driven to rotate.

Due to this rotational drive, the heating rotating body 36 on the outside of the heating core body 30 rotates integrally with the next blow-molded product]0. Such rotation and revolution is carried out from the entrance position A to the exit position B, and the heating for crystallization described below is performed during this period.

Next, the crystallization operation of the primary blow-molded product [mouth part] 4 in this crystallization apparatus will be explained.

In this embodiment, the outer surface and inner surface of the mouth portion 14 are individually heated. First, heating of the outer surface of the mouth portion 14 will be explained.

As for the heating effect on the outer surface of the mouth portion 14, there are the following two heating effects depending on the person. First, area a shown in Figure 1
is a region corresponding to the locking ring 18a and the port ring 8b in the mouth portion]4, and this region a is heated by radiant heat. A heater 24 is provided on the outer surface 22a of the thick heating portion 22 facing the region a.

The heating thick portion 22 heated by the heater 24 has a larger heat capacity than other regions of the heat treatment container 20. Furthermore, the inner surface 22b of this thick part for heating 22
Since the partition wall between the opening and the outer surface of each of the openings 1.8a, ], and 8b is set narrowly, the portion corresponding to the region a of the mouth portion 14 can be efficiently heated by radiation. In this embodiment, the surface temperature of the heater 24 is set to 240 to 270°C, for example.
radiant heat sufficient for crystallization for area a, preferably 80 to 180°C, more preferably 1
Knee that provides thermal energy of 00 to 160℃ 18
＝ It's sharp. Incidentally, the inner surface 22b of the thick heating inner part 22 may be coated with, for example, a far-infrared radiating material and ink may be applied to improve the radiant heat efficiency.

Next, the area in the mouth portion 14 corresponds to the neck portion 16 and its top surface roller a whose dimensional accuracy is important for the sealing function.

In this area as well, when heated at a high temperature by radiant heat as in area a above, the neck portion 16 and its top surface 16a, which are relatively thin and have a rapid temperature rise, undergo large thermal contraction, and when the camps are screwed together, The sealing function of the container may be impaired and the contents may leak. Therefore, in this embodiment, heating of this area is avoided by radiant heat, and is heated by exposing it to the heat atmosphere in the heat treatment container 20. The atmosphere inside the heat treatment container 20 is set at a predetermined temperature, for example, 240 to 320°C, by the radiant heat from the heater 24 and the radiant heat from the heating core body 30, and the area is gradually exposed to this hot atmosphere. Crystallization is performed without causing thermal contraction when heated.

Next, crystallization of the inner wall surface of the mouth portion 14 will be explained. A heating core body 30 is inserted into this mouth part 14, and a heating rotating body 36 forming the outer layer is in close contact with the inner wall surface of the mouth part 14,
- Rotates integrally with the mouth portion 14 due to the rotational drive of the next blow-molded product 10.

Therefore, by circulating hot water whose temperature is controlled to a predetermined temperature through the hot water jacket 34 formed on the core material 32 of the heating core body 30, the heat is transferred to the core material 32. Via the heating rotating body 36,
mouth] 4 is transmitted to the inner wall surface. In this way, by inserting the heating core body 30 into the mouth part 14, the mouth part]
4 to prevent thermal deformation, and the heating temperature by the heating core body 30 in direct contact with the inner wall of the mouth portion 14 is preferably 80 to 180°C, more preferably 100 to 180°C.
By setting the temperature to 60'C, the inner wall can be efficiently heated. In this manner, by efficiently heating both the inner and outer walls of the mouth 14, the processing time for crystallizing the entire mouth 4 can be significantly shortened compared to the conventional method. In this example, one cycle of transport on the circumferential path in the crystallization apparatus shown in FIG. 3 = 20 - time is set to, for example, 150 seconds, and almost the entire mouth portion 4 is crystallized within this short time. I was able to do that.

In addition, when heating the above-mentioned mouth part] 4, since the cooling holding part 26 supporting the support ring 18b is cooled, thermal deformation of the support ring 1.8b and the shoulder part below it can be prevented.

Next, the function of the air vent 40 provided in the heating core body 30 will be explained.

In this embodiment, a plurality of vertical grooves 4 are provided on the surface 36a of the rotating body 36.
2 is formed. This longitudinal groove 42 allows the surface 36
The air accumulated in the slight space between the inner wall surface of the mouth portion 4 and the opening portion 4 can be released into the heat treatment container 20 . If such air bleed is not performed, the air accumulated in the spacer will thermally expand, causing distortion and deformation of the opening 4. However, air bleed as in this example will cause deformation. This makes it possible to maintain the mouth portion 14 with high dimensional accuracy.

The vertical grooves 42 mainly include the surface 36 of the heating rotor 36.
The purpose is to remove air between the inner wall surface of the mouth part ] 4 and the inside of the heat treatment container 20 and the body part] 2 of the primary blow-molded product 10 through this vertical groove 42.
It is also possible that it works as follows. That is, by inserting the heating core body 30, the air inside the body 12 of the primary blow-molded product 10 is also thermally expanded. Since this expanded air can be released into the heat treatment container 20 along the vertical grooves 42, it is also possible to prevent the interior of the body 12 from being deformed by the thermally expanded air.

Note that various modifications can be made to the number and shape of the grooves for air removal.

FIG. 4(B) shows a heating rotating body 3 in place of the vertical groove 42.
A spiral groove 44 is formed on the surface 36a of 6. In addition to ensuring the above-mentioned effect by this spiral groove 44, the heating rotary body 36
0 in the direction of the arrow C in the figure, the air in the spiral groove 44 is guided upward while rotating along the direction of the arrow in the figure, allowing the air to escape efficiently into the heat treatment 20. Become. This spiral groove 44 can also be formed in a plurality of strips.

Note that the vertical groove 42 in FIGS. 4(A) and 4(B). The configuration of the helical groove 44 can also be applied to a heating core body 30 that does not include the heating rotating body 36, that is, a heating core body that is configured only with the core material 32.

FIG. 4(C) shows an example in which the heating core body 30 is not rotated and is provided with an air vent.

Surface 3 of heating core body 30 in rotational contact with the inner wall of mouth 14
0a is provided with a large number of horizontal holes 46 that open in the surface 30a and extend toward the center, and each horizontal hole 46 has a vertical hole 48 that passes through the center of the heating core body 30 in the axial direction. It's communicating. According to such a configuration, the surface 3
The air accumulated between 0a and the inner wall surface of the mouth portion 14 flows through the horizontal hole 4.
6 to a vertical hole 48, and is discharged to the outside air through this vertical hole 48. By penetrating the lower end side of this vertical hole 48 so as to communicate with the body 2 of the secondary blow-molded product 10, it becomes possible to release the expanded air in the body 12 to the outside air. In the case of releasing only the expanded air inside the body 12, it is sufficient to provide only one or more vertical holes 48 through the body.

In addition, as shown in FIG. 4(C), when the heating rotating body 36 is not provided, the surface 30a of the heating core body 3o and the inner wall surface of the mouth portion 14 come into rotational contact. In such a case, apply tetrafluoroethylene resin to 3°a of the surface.
Those coated with a resin that improves slipperiness, such as silicone resin, are preferable. Such a resin coating can prevent the surface 36a of the heating core body 30, which has a high surface temperature, from impairing the rotation of the mouth portion 14 due to rough skin.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

In the above example, the crystallization of the mouth part 4 was performed on the mouth part 14 of the primary blow molded product 10, but if it is in the state after the injection molded preform, the preform, the molding after heat shrinkage It is also possible to crystallize the mouth of the product or the final container in the form of a molded product.

[Effects of the Invention] As explained above, according to the method and apparatus of the present invention, even by heat treatment for crystallization of the mouth of a hollow container, deformation due to thermal contraction of the mouth can be minimized, and in particular, It is possible to prevent thermal deformation of the seal molding part, which requires high precision.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of the heat-treated part in the mouth crystallization apparatus to which the present invention is applied; FIG. 2 is a schematic cross-sectional view of the heat-treated part and the next blow-molded product; FIG. 4(A) to 4(C) are schematic perspective views for explaining air vents formed in the heating core body, respectively. 14・Mouth,] 6 Neck portion, 1, 6 a Top surface, 20...Heat treatment container, 24・Heater, 26 Cooling holding part key, 30 Heating core body, 34
・Hot water jacket, 36 Heating rotating body, 40... Air vent, 42... Vertical groove, 44... Spiral groove, 46... Horizontal hole, 48 Vertical hole, 60... Rotating disk, 62... Support arm, 64・Rotating body, 68・ Rib.

Claims (6)

[Claims] (1) The opening side of the hollow container has a mouth with a sealing molded part, and when crystallizing the molded resin in the mouth, the heating temperature of the outer wall surface of the sealing molded part is set to A method for crystallizing the mouth of a hollow container, characterized by heating at a temperature lower than that of the outer wall of the mouth. (2) In an apparatus for crystallizing the molded resin in the mouth, which has a mouth having a seal molding part on the opening side of the hollow container, at least the outer wall surface of the seal molding part and the periphery of the top surface thereof. Claim (1) characterized in that it is provided with: a heat treatment container with a thermal atmosphere; and a heating means arranged at a position facing an outer wall surface of the mouth portion other than the seal molding portion and heating the outer wall surface by radiation. ) Apparatus for carrying out the method. (3) having a mouth on the opening side of the hollow container, heating the outer wall surface of the mouth while inserting the core body inside the mouth;
An apparatus for crystallizing molded resin in a mouth part, characterized in that an air release path for releasing air between the outer wall surface of the core body and the inner wall surface of the mouth part is formed in the core body. Part crystallization equipment. (4) having a mouth on the opening side of the hollow container, heating the outer wall surface of the mouth while inserting the core body inside the mouth;
An apparatus for crystallizing a molded resin at a mouth of a hollow container, characterized in that an air release path for releasing air inside the hollow container to the outside is formed in the core body. (5) having a mouth on the opening side of the hollow container, heating the outer wall surface of the mouth while inserting the core body inside the mouth;
An apparatus for crystallizing molded resin at a mouth of a hollow container, wherein the core body has a built-in heating means for heating an inner wall surface of the mouth to a predetermined temperature in a range of 100 to 180°C. Part crystallization equipment. (6) In any one of claims (2) to (5), means for revolving a plurality of the hollow containers at predetermined intervals along a circumferential path that goes almost once; and during the revolution, the hollow containers A device for crystallizing the mouth of a hollow container, characterized in that the crystallization device is provided with means for rotating the crystal on its own axis, and performs one cycle of crystallization treatment by following the circumferential path.