JPH089201B2 - Method and apparatus for crystallizing mouth of hollow molded product - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and a device for heating and crystallizing an opening-side mouth of a hollow molded article 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 a mouth of a hollow molded article, which can satisfy the dimensional accuracy required for the crystallized mouth.

[Prior Art] When a hollow container is manufactured by biaxial stretch blow molding, its barrel is biaxially molecularly oriented and has excellent mechanical properties, but its mouth does not undergo molecular orientation, so only mechanical properties are obtained. Or
It is also inferior in heat resistance when filling the heat-treated contents for sterilization. Therefore, it is known in JP-A-54-68385, etc. that the mouth portion is locally heated and then gradually cooled to be crystallized to enhance mechanical properties and heat resistance.

Further, as a heating method for the mouth portion, one having a core body inserted into the mouth portion in order to regulate the inner diameter dimension of the mouth portion at the time of heating is known. JP-A-64-55228 discloses a core body having a high thermal conductivity, and JP-A-2-8821.
No. 7 discloses that the core body is preheated and then inserted into the mouth. In JP-B-61-1288, a concave or convex pattern is provided on the outer surface of the core body in the axial direction to regulate the thermal contraction in the axial direction. What is done is disclosed respectively.

Further, Japanese Patent Application Laid-Open No. 2-67119 discloses a method in which the local heating of the locking ring and the heating of the screw portion on the locking ring are separately performed. It is disclosed that a core body having a cooling function is inserted into a mouth portion and gradually cooled.

[Problems to be Solved by the Invention] When the inventors of the present invention repeatedly conducted experiments when crystallizing the mouth, a seal between the crystallized mouth and a cap or the like mounted after filling the contents In many cases, the molding part for use, that is, the screw part and its top surface are deformed by heat shrinkage.

With respect to such a problem, according to the conventional proposals (1) to (3), the inner diameter of the mouth portion is restricted by the core body inserted in the mouth portion, and only the dimensional accuracy of the inner wall surface of the mouth portion is maintained.
Further, in the publication, the deformation of the mouth portion in the axial direction is prevented, but the deformation of the sealing molding portion cannot be completely prevented. The above proposal only achieves complete crystallization of the mouth portion regardless of the difference in outer diameter, and does not contribute to the achievement of the above-mentioned problems.

Therefore, an object of the present invention is to provide a method and apparatus for crystallizing a mouth part of a hollow molded article, which can further improve the dimensional accuracy of the crystallized mouth part and can realize a mouth part having a high sealing effect. To do.

[Means for Solving the Problem] In the method of the present invention, the hollow molding has an opening-side opening having a sealing molding formed of a screw portion and a top surface thereof, and the molding resin at the opening is crystallized. In doing so, the heating temperature of the outer wall surface of the sealing molding portion is set to be lower than the heating temperature of the other outer wall surface of the mouth portion, and heating is performed.

The apparatus of the present invention for carrying out this method includes: a heat treatment container having a heat atmosphere around at least the outer wall surface of the molding portion for sealing; and a heat treatment container arranged at a position facing the outer wall surface of the mouth portion other than the seal molding portion. And heating means for radiantly heating the wall surface.

The present invention has an improved apparatus that has a mouth on the opening side of a hollow molded article and heats the outer wall surface of the mouth while inserting a core inside the mouth to crystallize the molding resin in the mouth. In the device, the core body is formed with an air discharge path for discharging air between the outer wall surface of the core body and the mouth and inner wall surface, or an air discharge path for discharging air inside the hollow container to the outside. There is.

Similarly, in the device of the present invention in which the device for inserting the core body into the mouth portion is improved, the core body inserted into the mouth portion is heated to a predetermined temperature in the range of 100 to 180 ° C. on the inner wall surface of the mouth portion. Has built-in heating means.

[Operation] As a subject focused on by the inventors of the present invention, it is necessary to secure high dimensional accuracy of the sealing molding portion formed of the screw portion and the top surface of the mouth portion. Since this region is thinner than the other regions such as the locking ring and the support ring, the heat capacity is small, and by setting the heating temperature lower than the other regions, it is possible to provide sufficient heat for crystallization. It is possible to suppress excessive temperature rise and prevent deformation due to thermal contraction.

This method can be realized by a device that only exposes the molding part for sealing to a hot atmosphere and heats other regions by radiant heat.

As an improvement of the device for inserting the core body into the mouth, the present inventors have focused on the harmful effect of the expanded air staying 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 can be solved by forming an air discharge path in the core body that allows the expanded air to escape. Further, since the opening side is sealed by the core body, it is considered that the expanded air inside the hollow molded article has no escape and causes deformation of the mouth portion. It is also useful to prevent the deformation of the mouth by forming the expansion air discharge path inside the molded product in the core body.

Conventionally, the core body to be inserted into the mouth is not made to have a built-in heating means but is simply made of a material having good thermal conductivity, or preheated before being inserted. The heating from the inner wall side of the mouth that can regulate the temperature, and the heating that is built in the core body and can maintain a predetermined temperature throughout the heating enables more uniform heating and contribute to prevention of deformation of the mouth. Here, if the heating temperature of the heating means built in the core body is lower than 100 ° C., it takes too long to crystallize, which is not practical in the processing cycle for crystallization.
If the heating temperature exceeds 180 ° C., the inner wall surface of the mouth portion becomes rough or the mouth portion itself is deformed when the core body is pulled out from the mouth portion, which is not preferable. Further, if the heating from the outer wall of the mouth is also performed, the heat treatment time until crystallization can be shortened.

Each of the above-mentioned crystallization devices has a substantially circular path,
A large number of hollow molded products are revolved and conveyed, and the hollow molded products are revolved while revolving, so that a continuous and uniform crystallization process can be performed at a relatively small space.

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

In this embodiment, after the preform is molded, the heat-resistant hollow container as the final container is molded through each of the primary blow molding process, the heat shrinking process, and the secondary blow molding process.
Such a molding method is disclosed and known in JP-A-62-270316.

In the above-described molding method, each blow molding is carried out at a low intermediate temperature by one blow molding process as compared with the molded container, and in the preceding process, at each high clear temperature. As it undergoes heat treatment, it has two distinct biaxial crystallographic orientations, which significantly enhances the mechanical resistance of the container placed in severe temperature conditions in the final process,
It is known that a heat resistant hollow container can be obtained.

By the above molding process, the heat resistance of the bottomed cylindrical body of the hollow container is ensured, and the apparatus and method for ensuring the heat resistance of the mouth, which is a feature of the present invention, will be described below. A description will be given with reference to FIGS. 1 to 3.

In the present embodiment, the heat resistance of the mouth portion 14 is improved by crystallizing and whitening the mouth portion 14 of the primary blow-molded product 10 formed of, for example, poly-ethylene terephthalate. This primary blow-molded product 10 is obtained by biaxially stretch-blow molding a preform (not shown) which has been injection-molded in advance, and has the mouth portion 14 on the opening side of the bottomed cylindrical body portion 12. ing. The mouth portion 14 is composed of a screw portion 16 formed on the upper side thereof and with which a cap is screwed, and a locking ring 18a and a support ring 18b on the lower side thereof, which are preliminarily formed in a preform injection molding process. It is molded with high dimensional accuracy. Particularly, since the threaded portion 16 and the top surface 16a thereof function as a sealing molding portion when the cap is screwed, high dimensional accuracy must be maintained even in the final container.

A heat treatment container 20 is provided as a crystallization device for the mouth portion 14. The heat treatment container 20 is formed so as to cover the top surface 16a of the mouth portion 14 and the periphery of the screw portion 16, and the lower end portion thereof is open. At this lower end side, the locking ring 18a,
At the position facing the support ring 18b, the heating thick portion 22
Is provided, and the gap between each of the rings 18a and 18b is set to be narrower. The outer surface of the heating thick portion 22
A heater 24 is provided at 22a. A cooling holding member 26 is provided in close contact with the lower end opening side 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 hermetically seal the inside thereof at a predetermined airtightness,
And a cooling water jacket for circulating a cooling medium such as cold water
Has 28 built-in. This cooling holding member 26 is, for example, the first
The ring hole is divided into two parts that can be opened and closed in the left-right direction in the drawing, and the ring hole formed so as to face the divided surface is inserted directly below the mouth portion 14 to support the lower surface of the support ring 18b on the cooling holding member 26. It is configured to be possible. As a result, the primary blow-molded product 10 is supported by this cooling holding member 26.

The above configuration is an apparatus for heat treatment of the outer wall of the mouth portion 14, and in this embodiment, in order to perform the heat treatment of the inner wall of the mouth portion 14, a heating core body 30 inserted in the mouth portion 14 is provided. There is. The heating core body 30 is roughly divided into a core material 32 in the central portion,
It consists of the heating rotator 36 in the periphery and the heating rotator 36 is the core material.
It is rotatably supported with respect to 32. The core member 32 has a warm water jacket 34 capable of circulating a temperature control fluid such as warm water.
Is provided. By circulating hot water in the hot water jacket 34, it becomes possible to heat the inner wall surface of the mouth portion 14 through the core material 32 and the heating rotator 36.

An air vent 40 is provided on the surface 36a of the heating rotator 36. The air vent 40 is mainly for releasing air accumulated in a slight gap between the surface 36a of the heating rotator 36 and the inner wall surface of the mouth portion 14. In this embodiment, as shown in FIG. 4 (A), the air vent 40 is composed of vertical grooves 42 formed in a concave shape along the vertical axis at predetermined intervals in the circumferential direction of the heating rotor 36. The upper end of the vertical groove 42 is set at a position higher than the top surface 16a of the mouth portion 14 and communicates with the inside of the heat treatment container 20, and the lower end thereof communicates with the inside of the body portion 12 of the primary blow-molded product 10. As shown in FIG. 2, the heater 24 is provided on the upper end side of the heating core body 30.
A heater controller 50 for controlling the temperature of the above, and an import 34a and an out port 34b connected to the hot water jacket 34 are provided.

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

In the present embodiment, the primary blow-molded product 10 is advanced along the circumferential path, and the lips 14 are crystallized with one cycle of the primary blow-molded product 10 as one cycle. To this end, a rotary disk 60 is provided, and a large number of support arms 62 are provided on the periphery of the rotary disk 60 at predetermined intervals in the circumferential direction.
The heat treatment container 20, the cooling holding member 26, the heat treatment container 20 and the like are supported by 62. Further, a rotatable rotating body 64 is provided on the side wall of the rotating disk 60. The rotary bodies 64 are arranged as two rotary bodies 64a and 64b at positions corresponding to the respective support arms 62, and the cooling holding member 26 is provided.
It is in rolling contact with the body portion 12 of the primary blow-molded product 10 supported by. Furthermore, the outer wall cover arranged concentrically with the rotating disk 60.
On the inner surface of 66, ribs 68 protruding so as to come into contact with the body portion 12 of the primary blow-molded product 10 are provided over the region excluding the region for loading and unloading the primary blow-molded product 10 into the crystallization device. Is formed. Therefore, when the rotary disc 60 rotates, the primary blow-molded product 10 revolves, and the rotation of the primary blow-molded product 10 due to contact with the ribs 68 during this revolution causes the two rotary bodies 64a, It will rotate while being rotated and guided by rolling contact with 64b.

This crystallization device is provided with a carry-in guide 70 and a carry-out guide 74 for carrying in and out the primary blow-molded product 10, and each of the guides 70, 74 is moved straight ahead.
Has curved portions 72 and 76 for guiding the path to the circumferential path or for guiding the straight path from the circumferential path. Further, feeding mechanisms 80 and 82 for step-feeding the primary blow-molded products 10 one by one along the curved portions 72 and 76 are provided. This each feeding mechanism 8
As the rotational driving force of 0, 82, the driving force of the sprocket 84 rotated by a driving source such as a single motor is transmitted to each feeding mechanism 80, 82 via a plurality of chains and sprockets, and both feeding mechanisms are driven. 80,82 synchronous drive is performed. In addition, the inlet position A of the primary blow-molded product 10 in the circumferential path
Then, the closing drive of the cooling holding member 26 and the heating core body 30
At the outlet position B, the opening drive of the cooling holding member 26 and the detachment drive of the heating core body 30 are performed. Each of such drives is, for example, the rotating disk.
A cam drive based on the driving force of 60 can be adopted.

Hot water supply / drainage to each heating core body 30, cooling holding member 26
Cooling supply / drainage to the heater controller 50 and power supply to the heater controller 50 are performed along an arm (for example, there are two at the top and bottom) 90 from the outside of the rotating disk 60 toward the center thereof. It is connected to the central shaft portion 92. Then, from the central shaft portion 92 toward the respective portions on the circumference, warm water /
A large number of sets, each including the cold water pipe 94a and the power cable 94b, extend radially.

Next, the operation of the apparatus of the above embodiment will be described. The primary blow-molded product 10 goes straight along the carry-in guide 70 on the right side of FIG. 3, and is guided to rotate along the curved portion 72 by the rotation drive of the feed mechanism 80, and the inlet position of the circumferential path of the mouth crystallization device. Reach A. In this position A, the cooling holding member 26 is driven to be closed, and the support ring 18b of the primary blow-molded product 10 is supported by the cooling holding member 26. Further, the heating core body 30 is driven downward, and the tip end portion thereof is inserted into the mouth portion 14. At this time, since the rotary disc 60 is rotationally driven, the primary blow molded product 10 is revolved along with the cooling holding member 26, the heat treatment container 20 and the heating core body 30 attached to the support arm 62 of the rotary disc 60. Will be. Due to this rotational drive, the body 12 of the primary blow-molded product 10 is
When the ribs 68 come into contact with each other, a rotation force is applied by the ribs 68, and the primary blow-molded product 10 is driven to rotate while rollingly contacting the two rotating bodies 64a and 64b. By this rotation drive, the outer heating rotary body 36 of the heating core body 30 rotates integrally with the primary blow-molded product 10. Such rotation and revolution is performed from the inlet position A to the outlet position B, and the heating for crystallization described below is performed during that period.

Next, the crystallization operation of the mouth portion 14 of the primary blow-molded product 10 in this crystallization device will be described.

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

The heating action of the outer surface of the mouth portion 14 is roughly classified into the following two heating actions. First, the area a shown in FIG.
Is a region corresponding to the locking ring 18a and the support ring 18b in the mouth portion 14, and the 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 area a. The heating thick part 22 heated by the heater 24 has a larger heat capacity than the other regions of the heat treatment container 20. Further, the inner surface 22b of the thick wall portion 22 for heating and the respective 18a, 1
Since the space between the outer surface of 8b and the outer surface is set to be narrow, the portion of the mouth portion 14 corresponding to the region a can be efficiently radiantly heated. In the present embodiment, the surface temperature of the heater 24 is set and maintained at, for example, about 240 to 270 ° C., and radiant heat sufficient for crystallization to the region a, preferably 80 to 180 ° C., more preferably 100 to 160 ° C. Heat energy can be applied. The inner surface 22b of the thick heating portion 22 may be coated with, for example, a far-infrared radiation material to improve the radiation heat efficiency.

Next, the region b in the mouth portion 14 corresponds to the threaded portion 16 and the top surface 16a thereof whose dimensional accuracy is important for the sealing function.

In this region b as well, similar to the above-mentioned region a, when heated at a high temperature by radiant heat, the heat shrinkage of the screw portion 16 and its top surface 16a, which are relatively thin and have a rapid temperature rise, is large, and when the cap is screwed together. The sealing function may be impaired, and leakage of the filled contents may occur. Therefore, in the present embodiment, heating by radiant heat is avoided in this region b,
Heating is performed by exposing the heat treatment container 20 to the hot atmosphere. The atmosphere inside the heat treatment container 20 is the same as the heater.
By radiant heat from 24 and radiant heat from the heating core body 30,
A predetermined temperature, for example, 240 to 320 ° C. is set, and the region b is exposed to this hot atmosphere to gradually heat it and crystallize it without causing heat shrinkage.

Next, crystallization of the inner wall surface of the mouth portion 14 will be described. The heating core body 30 is inserted in the mouth portion 14, the heating rotor 36 forming the outer layer thereof is in close contact with the inner wall surface of the mouth portion 14, and is integrated with the mouth portion 14 by the rotation drive of the primary blow molded product 10. Is rotating. Therefore, by circulating hot water whose temperature has been adjusted to a predetermined temperature in the hot water jacket 34 formed on the core material 32 of the heating core body 30, the heat is circulated through the core material 32 and the heating rotary body 36.
It will be transmitted to the inner wall surface of 4. In this way, by inserting the heating core body 30 into the mouth portion 14, the inner diameter of the mouth portion 14 is regulated to prevent thermal deformation, and the heating temperature by the heating core body 30 that directly contacts the inner wall of the mouth portion 14 Also preferably, 80-180
The inner wall can be efficiently heated by setting the temperature to ℃, more preferably 100 to 160 ℃. As described above, by efficiently heating both the inner wall and the outer wall of the mouth portion 14, the processing time for crystallizing the entire mouth portion 14 can be significantly shortened as compared with the conventional case. In the present embodiment, the one cycle conveying time on the circumferential path in the crystallization apparatus shown in FIG. 3 was set to, for example, 150 seconds, and almost the entire mouth 14 could be crystallized within this short time. .

Since the cooling holding member 26 supporting the support ring 18b is cooled during the above-described heating of the mouth portion 14, it is possible to prevent thermal deformation of the support ring 18b and the shoulder portion below the support ring 18b.

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

In this embodiment, a plurality of vertical grooves 42 are formed on the surface 36a of the rotating body 36. Due to this vertical groove 42, the surface 36a and the mouth portion 1
The air accumulated on a small wall between the inner wall surface of 4 and the inner wall surface of 4 can be released to the inside of the heat treatment container 20. If such air bleeding is not performed, the air accumulated on the above-mentioned wall will be thermally expanded and the mouth portion 14 will be distorted and its deformation will occur, but by performing the air bleeding as in this embodiment, It is possible to maintain the mouth portion 14 with high dimensional accuracy. The vertical groove 42 is mainly for bleeding air between the surface 36a of the heating rotor 36 and the inner wall surface of the mouth portion 14. By this vertical groove 42, the heat treatment container 20, the inside, and the primary blow molded product are formed. By communicating with the body 12 of 10, it is possible to act as follows. That is, when the heating core body 30 is inserted, the air inside the body portion 12 of the primary blow-molded product 10 also thermally expands. Since this expanded air can escape to the inside of the heat treatment container 20 along the vertical groove 42, it is possible to prevent the deformation of the inside of the body portion 12 due to the thermally expanded air.

It should be noted that various modifications can be made to the number and shape of the grooves for this air bleeding.

FIG. 4B shows a heating rotary member 36 instead of the vertical groove 42.
A spiral groove 44 is formed on the surface 36a of the. In addition to the fact that the spiral groove 44 can ensure the above-mentioned action, when the heating rotary body 36 rotates in the direction of arrow C in the figure together with the primary blow-molded product 10, the air in the spiral groove 44 becomes the direction of arrow D in the figure. Guided upward while rotating along
The air can be efficiently released inside the heat treatment 20. The spiral groove 44 may be formed in a plurality of lines.

In FIGS. 4A and 4B, the vertical groove 42 and the spiral groove 44 are configured such that the heating core body 30 does not have the heating rotor 36, that is, the heating core body is composed of only the core material 32. It can also be applied to things.

FIG. 4 (C) shows an example in which an air vent is provided in the non-rotating heating core body 30. On the surface 30a of the heating core body 30 which is in rotary contact with the inner wall of the mouth portion 14, a large number of lateral holes 46 opening toward the surface 30a and directed toward the center are provided, and each of the lateral holes 46 of the heating core body 30. Each of them communicates with a vertical hole 48 that penetrates in the axial direction at the center. According to such a configuration, the air accumulated between the surface 30a and the inner wall surface of the mouth portion 14 is guided to the vertical hole 48 through the horizontal hole 46 and discharged to the outside air through the vertical hole 48. Will be. By penetrating the lower end side of the vertical hole 48 so as to communicate with the body portion 12 of the primary blow-molded product 10, the expanded air in the body portion 12 can be discharged to the outside air. When only the expanded air in the body portion 12 is discharged, only one or more of the vertical holes 48 may be provided so as to penetrate therethrough.

As shown in FIG. 4 (C), when the heating rotary body 36 is not provided, the surface 30a of the heating core body 30 and the mouth portion 14 are
Will be in rotational contact with the inner wall surface of the. In such a case, it is preferable to coat the surface 30a with a resin such as a tetrafluoroethylene resin or a silicone resin, which improves the slipperiness. With such a resin coating,
It is possible to prevent the surface 36a of the heating core body 30 having a high surface temperature from damaging the rotation of the mouth portion 14 due to rough skin.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

In the above embodiment, the crystallization of the mouth portion 14 is performed by the primary blow molding product.
It was performed for the mouth portion 14 of 10, but if it is in the state after the extrusion molded preform, the crystal of the mouth portion in the state of the preform, the molded product after heat shrinkage or the molded product of the final container. It can also be converted.

[Effects of the Invention] As described above, according to the method and the device of the present invention, even by the heat treatment for crystallizing the mouth of the hollow molded article,
It is possible to suppress the deformation of the mouth portion due to the heat shrinkage to a minimum, and to prevent the heat deformation of the molding portion for sealing, which requires particularly dimensional accuracy.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a heat treatment section in a mouth crystallization apparatus to which the present invention is applied, FIG. 2 is a schematic sectional view of a heat treatment section and a primary blow-molded product 10, and FIG. 3 is a mouth crystallization apparatus. And FIG. 4 (A) to (C) are schematic perspective views for explaining the air vents formed in the heating core body. 14 …… Mouth, 16 …… Screw, 16a …… Top surface, 20 …… Heat treatment container, 24 …… Heater, 26 …… Cooling holding member, 30 …… Heating core body, 34 …… Hot water jacket, 36 ...... Heating rotator, 40 …… Air vent, 42 …… Vertical groove, 44 …… Helix groove, 46 …… Horizontal hole, 48 …… Vertical hole, 60 …… Rotating disk, 62 …… Support arm, 64 …… Rotating body, 68 ... rib.

Claims (6)

[Claims] 1. A hollow molded article is provided with a molding portion for sealing composed of a screw portion and a top surface thereof at a mouth portion on the opening side, and in crystallizing a molding resin of the mouth portion, the molding portion for sealing is A method for crystallizing a mouth portion for a hollow molded article, characterized by setting the heating temperature of the outer wall surface to be lower than the heating temperature of the other outer wall surface of the mouth portion. 2. An apparatus for crystallizing a molding resin at a mouth, which comprises a molding portion for a sheet, which comprises a screw portion and a top surface thereof, at the mouth portion on the opening side of the hollow molded article, and at least the molding for sealing. A heat treatment container having a heat atmosphere around the outer wall surface of the section, and a heating unit arranged at a position facing the outer wall surface of the opening other than the sealing molding section and radiatively heating the outer wall surface. An apparatus for crystallizing the mouth of a hollow molded article for carrying out the method according to claim (1). 3. A hollow molded article has a mouth on the opening side, and the outer wall surface of the mouth is heated while the core body is inserted inside the mouth to crystallize the molding resin in the mouth. An apparatus for crystallizing a mouth part of a hollow molded article, wherein an air discharge path for discharging 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. 4. A hollow molded article has a mouth on the opening side, and the outer wall surface of the mouth is heated while the core body is inserted inside the mouth to crystallize the molding resin in the mouth. An apparatus for crystallizing a mouth of a hollow molded product, wherein an air discharge path for discharging air inside the hollow molded product to the outside is formed in the core body. 5. A hollow molded article has a mouth portion on the opening side, and the outer wall surface of the mouth portion is heated while the core body is inserted inside the mouth portion to crystallize the molding resin in the mouth portion. In the apparatus, the core body has a heating means for heating the inner wall surface of the mouth portion to a predetermined temperature in the range of 100 to 180 ° C., the mouth portion crystallization apparatus for a hollow molded article. 6. A means for revolving a plurality of the hollow molded products at a predetermined interval along a substantially circular path, and means for revolving during this revolving, according to any one of claims (2) to (5). A means for crystallizing the mouth of a hollow molded product, characterized in that a means for rotating the hollow molded product is provided and one cycle of crystallization treatment is performed by following the circumferential path.