JPS6367467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for crystallizing a saturated polyester hollow body, and more specifically to a crystallization apparatus for a saturated polyester hollow body, and more specifically, a crystallizing apparatus for crystallizing a saturated polyester hollow body, such as a parison or bottle with a bottom made of a saturated polyester such as polyethylene terephthalate. The present invention relates to a device for crystallizing the mouth and neck.

(Prior art) Bottles made of saturated polyester are usually manufactured by biaxially stretching blow molding a bottomed parison of an amorphous structure formed by injection molding, etc., leaving the part that will become the neck and mouth part. be done. Because of the molecular orientation of the shoulders, body and bottom, this type of bottle has transparency, gas barrier properties,
Bottles with excellent container properties such as strength and impact resistance, and which have these parts heat-set, have a high resistance to heat when hot-filled (usually refers to filling with young-use products heated to about 90°C). , these parts have the advantage that deformation due to shrinkage is unlikely to occur.

However, since the mouth and neck region remains amorphous tissue, it is relatively soft, and therefore, foreign objects may hit the end surface during handling before sealing, causing scratches, or the entire mouth and neck region or the threaded portion may be damaged during hot filling. etc. may be deformed and the sealing performance may be impaired.

In order to overcome this drawback, a technique has been proposed in which the hardness and heat resistance of the mouth and neck area are improved by heating and crystallizing the mouth and neck area. In this case, as the crystallization occurs, the density increases, the volume decreases, and the neck becomes irregularly deformed, making it difficult to close the cap or causing a decrease in sealing performance. . In order to solve this problem, JP-A-58-
Publication No. 173628 describes a core made of heat-resistant resin,
A method has been proposed in which the core is inserted into the mouth and neck, the inner circumferential surface of the mouth and neck is tightly engaged with the outer circumferential surface of the core, and the inner circumference of the mouth and neck is regulated by the core, and the mouth and neck are heat-treated and crystallized. has been done.

(Problems to be Solved by the Invention) When crystallizing using the above conventional method, the inner circumferential surface of the mouth and neck and the outer circumferential surface of the core are tightly engaged;
Since the mouth and neck crystallize and contract, the core is strongly tightened by the mouth and neck after crystallization.
A problem arises in that it is extremely difficult to extract the core from the mouth and neck.

(Objective of the Invention) An object of the present invention is to provide an apparatus for crystallizing the mouth and neck of a saturated polyester hollow body without causing irregular deformation of the mouth and neck.

Another object of the present invention is to provide an apparatus for crystallizing the neck and neck of a saturated polyester hollow body, from which the core can be easily extracted after crystallization.

(Structure of the Invention) The present invention provides an apparatus for crystallizing the mouth and neck of a saturated polyester hollow body, the apparatus comprising: a holding device for the hollow body capable of rotating the hollow body around its axis; A main body having an outer diameter that is smaller than the previous inner diameter of the mouth and neck by approximately the amount of shrinkage of the inner diameter due to crystallization to the extent that it can be easily extracted from the mouth and neck after crystallization, and the main body is attached to the mouth and neck. A core made of a heat-resistant resin and having a flange having a lower surface that engages with the mouth and neck when inserted, a sliding pin that is slidably inserted through a through hole extending in the axial direction of the core, and the sliding pin. The core has an engaging body attached to the lower end and capable of engaging with the bottom surface of the core, for inserting the core into the mouth and neck before crystallization and extracting it from the mouth and neck after crystallization. A lifting device, a member for thermally insulating the outside of the mouth and neck and the outside of the lower part of the mouth and neck, a heating cover that houses the mouth and neck during crystallization, and a hot air nozzle that blows hot air into the heating cover. An apparatus for crystallizing a saturated polyester hollow body is provided.

(Means and effects for solving the problem) The device of the present invention includes a rotatable holding device for a hollow body, a heating cover for storing the mouth and neck, and a hot air nozzle for blowing hot air into the heating cover. , the mouth and neck can be heated for crystallization while rotating the hollow body around the axis, and therefore the mouth and neck can be heated uniformly in the circumferential direction, and also almost in the height direction. Can be heated evenly. Therefore, the entire mouth and neck region can be heated uniformly.

The outer diameter of the main body of the core made of heat-resistant resin, which is inserted into the mouth and neck, is larger than the inner diameter of the mouth and neck before crystallization, to the extent that it is easy to pull out the main body from the mouth and neck after crystallization. Since the inner diameter is smaller by approximately the amount of shrinkage due to crystallization, that is, the outer diameter is approximately equal to the inner diameter of the mouth and neck after crystallization, the core can be easily extracted.

At the beginning of heating, there is a slight gap between the inner circumferential surface of the mouth and neck and the outer circumferential surface of the core body to accommodate the shrinkage allowance, but this gap substantially disappears at the end of heating. Even if a large local shrinkage deformation occurs in the mouth and neck during heating, the inner surface of this part will come into contact with the outer peripheral surface of the core body, and the deformation will not progress beyond filling the gap. . Coupled with this and the fact that the mouth and neck are heated uniformly as a whole, the inner peripheral surface of the mouth and neck after crystallization becomes a substantially perfect circle in cross section, and irregular deformation of the mouth and neck is prevented. Prevented.

The core elevating device includes a sliding pin that is slidably inserted through a through hole extending in the axial direction of the core, and an engaging body that is attached to the lower end of the sliding pin and that can engage with the bottom surface of the core. Therefore, when the core lifting device is raised,
The sliding pin slides along the through hole of the core and rises, and the engaging body engages with the bottom surface of the core, and the core is pushed up by the engaging body. Therefore, by simply raising the core elevating device, the core whose outer diameter is determined as described above can be easily extracted from the mouth and neck.

When the core lifting device is lowered to insert the core into the mouth and neck, the engaging body engages with the bottom of the core until the bottom surface of the flange of the core engages with the mouth and neck. After mating, the sliding pin descends along the through hole of the core, and at the same time the engaging body also separates from the bottom surface of the core.

Therefore, by simply lowering the core elevating device, the lower surface of the flange of the core can be reliably engaged with the mouth and neck, and since no pressing force is applied to the core after engagement, the hollow body There is no risk of crushing it. Such advantages are difficult to obtain when the core is fixed to the core lifting device.

As described above, since the lower surface of the flange of the core can be reliably engaged with the mouth and neck, the angle θ between the lower surface of the flange and the horizontal plane can be set to 15 degrees or less, especially 0.
By adjusting the angle, the end face of the mouth and neck can be finished smoothly, and more reliable sealing performance can be obtained.

In addition, if the lower surface of the flange of the core extends radially outward and obliquely upward from the upper end of the main body, and when it is inserted into the mouth and neck of the main body and engages with the upper end of the inner peripheral surface of the mouth and neck, the end surface of the mouth and neck Since there is an outwardly expanding gap having a wedge-shaped cross section between the bottom surface and the bottom surface, the end surface is directly heated by the hot air blown into this gap. Therefore, the crystallization of the end face progresses relatively quickly, and therefore the hardness thereof also increases relatively quickly.

The device of the present invention is equipped with a member that thermally isolates the outside of the mouth and neck and the outside of the lower part of the mouth and neck, so that only the mouth and neck are crystallized and the lower part of the mouth and neck is crystallized. There is no fear.

In this specification, crystallization refers to a degree that can prevent deformation of the mouth and neck part to the extent that the sealing performance is impaired during hot filling, or damage to the extent that the sealing performance is damaged on the end face. This refers to crystallization to the extent that an increase in heat resistance and hardness can be seen. Therefore, the required degree of crystallinity varies depending on the use of the bottle, etc., and an average crystallinity of about 20 to 30% may be sufficient. be.

(Example) The present invention will be described below with reference to drawings which are examples.

In FIGS. 1 and 2, a crystallization apparatus 1 includes a holding device 3 rotatable around an axis for holding a bottle 2 made of saturated polyester, usually polyethylene terephthalate. A core 4 made of heat-resistant resin is inserted into the mouth and neck part 2a of the mouth and neck part 2, a core lifting device 5 for inserting the core 4 into the mouth and neck part 2a and extracting it from the mouth and neck part 2a, the outside of the mouth and neck part 2a, and the mouth and neck part 2a. Shoulder 2b below 2a
A heating cover 7 that houses the neck 2a at the end of crystallization, and a hot air nozzle 9 that blows hot air 8 into the heating cover 7 are provided.

Shoulder 2b, body 2c and bottom 2d of bottle 2
becomes a molecularly oriented structure during biaxial stretch blow molding, but the mouth and neck portion 2a remains an amorphous structure. The neck portion 2a includes a threaded portion 2a ₁ for screwing a pilfer-proof cap (not shown), an annular protrusion 2a ₂ for engaging a pilfer-proof band of the pilfer-proof cap, and a stopper. In order to receive the axial load, a retaining ring 2a ₃ is formed which engages with a retainer (not shown).

The holding device 3 is inserted into a corresponding slot 3a ₁ formed in its cylindrical body 3a and is inserted into the bottle body 2.
The lower part _2c1 of c is pressed in the radial direction by the action of the coil spring 10 to hold the bottle 2 vertically.
A pressing piece 11 is provided. Bottom plate 12 of holding device 3
A rotating shaft 13 is fixed to the bottom plate 12, and the bottom plate 12 can be raised and lowered by an air cylinder (not shown).

The heat shielding member 6 is preferably made of heat-resistant plastic with a low coefficient of friction such as fluororesin;
The inner circumferential surface 6a of the bottle 2 in the closed state (the state shown in FIG. 2)
It has a shape corresponding to the upper outer peripheral surface of b.
Each split piece of the heat shielding member 6 is fixed to the upper inner end of a retaining plate 14 made of a metal split piece 14a.
Each split piece 14a of the holding plate is provided with a cooling water hole 15 through which cooling water 16 flows. Each split piece 14a can be moved horizontally to open and close the heat shielding member 6 by an air cylinder (not shown).

The heating cover 7 is placed on the holding plate 14 when heating the mouth and neck part 2a, but in this case, the heating cover 7 is placed so that the bottom end 7a of its inner peripheral surface is located on the heat shielding member 6.
The shape and dimensions of the inner peripheral surface are determined. Holding plate 1
This is to prevent the temperature of the metal in step 4 from rising. The heating cover 7 is also movable up and down by an air cylinder (not shown). Note that 17 is an exhaust hole for the hot air 8, and 18 is a hole for introducing cold air to promote cooling of the mouth and neck area 2a after heating, and is connected to a blower (not shown) via a conduit (not shown). do. Hot air nozzle 9 is coil heater 1
9, and from a blower (not shown),
Air 21 is constantly sent through the conduit 20, and the air 2
1 is heated by a heater 19 and becomes hot air 8. Note that the heater 19 is controlled by a timer (not shown) so that it is energized only when heating the mouth and neck region 2a.

The core 4 is made of a heat-resistant resin with low thermal conductivity and low coefficient of expansion, such as polyimide resin. As shown in FIG. 3, the core 4 includes a main body 4a inserted into the mouth and neck 2a, and a flange 4b provided above the main body 4a. The outer circumferential surface 4a ₁ of the main body 4a has a perfect circle in cross section, and has a shape that almost corresponds to the slightly tapered inner circumferential surface 2a ₄ of the mouth and neck portion 2a. The inner diameter of the corresponding portion of the mouth and neck portion 2a before crystallization is approximately equal to the contraction amount of the inner diameter after heating for crystallization, and the inner diameter of the mouth and neck portion 2a after crystallization is
It is set small enough to be easily extracted from a. That is, the core 4a and the mouth and neck region 2a before crystallization.
The gap d between them is approximately 1/2 of the above shrinkage allowance. For example, if the mouth and neck part 2a is made of polyethylene terephthalate and the inner diameter of the inner circumferential surface _2a4 is 31.0 mm, hot air at about 500°C (air flow rate 50 liters/min) is blown in the device 1 for 2 minutes to crystallize it. The shrinkage margin of the inner circumferential surface 2a is 1.3 to 1.5 mm after the mouth and neck temperature is approximately 110 to 180°C. In this case, if the outer diameter of the core 4 corresponding to the inner diameter is 29.8±0.20 mm, no irregular deformation will occur in the crystallized neck portion 2a, and the inner peripheral surface will have a perfect circular cross section. Moreover, a good result is obtained in that the core 4 can be easily extracted. If the outer diameter of the core 4 is larger than the upper limit of the above range, it is likely to be difficult to extract, while if it is smaller than the lower limit, deformation will easily occur in the mouth and neck portion 2a.

The lower surface _4b1 of the flange 4b extends radially outward and obliquely upward from the upper end of the main body 4a, and connects the main body 4a to the mouth and neck part 2.
When inserted into a, the upper end 1 of the inner peripheral surface 2a ₄ of the mouth and neck
a ₄ ′. The angle θ between the lower surface _4b1 and the horizontal plane is preferably about 45 degrees or less, particularly 15 degrees or less. Further, by setting the angle θ to 15 degrees or less, particularly 0 degrees, the end face _2a5 of the mouth and neck portion 2a can be finished smoothly, and reliable sealing performance can be obtained. On the other hand, when the angle θ is larger than 45 degrees, when inserting the core 4 into the mouth and neck part 2a, the core 4
This is because the sealing material falls into the mouth and neck part 2a, making it difficult to position the mouth and neck part 2a in the height direction, and also making it impossible to obtain the smoothness of the end surface _2a5 of the mouth and neck part 2a, resulting in a loss of sealing performance.

The lifting device for the core 4 is equipped with a vertical rod 23 having a sliding pin 23a at the bottom that is slidably inserted through the center hole 4c of the core 4.
is moved up and down by an air cylinder for raising and lowering the heating cover 7. An annular body 24 that can engage with the bottom surface of the core 4 is attached to the lower end of the sliding pin 23a, and the vertical rod 23 is inserted through a through hole 25 provided at the top of the heating cover. There is.

Using the above-described apparatus 1, crystallization of the mouth and neck region 2a is performed as follows.

The holding device 3 of the bottle 2 is in the lowered position, the heating cover 7
The core 4 is in the raised position, the retaining plate 14 of the heat shielding member 6 is in the open position (both positions indicated by the dashed line), the heater 19 is deenergized, and cold air is flowing into the cooling inlet hole 18. In the unfeeding state, after inserting the bottle 2 into the holding device 3, the bottom plate 12
to raise the bottle 2 to the position shown by the solid line. Immediately, each split piece 14a of the retaining plate 14 moves to the position indicated by the solid line, and the retaining plate 14 and therefore the heat shielding member 6 are closed.

Next, the heating cover 7 and the core lifting device 5 are lowered to the position indicated by the solid line, and the core 4 is lowered as shown in FIG.
is inserted into the mouth and neck region 2a. Mouth and neck area under heating 2
Only the weight of the core 4 is loaded onto a. If a larger load than the lifting device 5 is applied to the mouth and neck part 2a through the core 4, the mouth and neck part 2a will be moved during heating.
This is because deformation is likely to occur in a. Heater 1 immediately
9 and rotate the rotating shaft 13 at the same time, preferably at a relatively low pressure (0.05 Kg/cm ² or less), about 400
Hot air 8 of ~500°C is blown onto the rotating mouth and neck area 2a. Therefore, the mouth and neck region 2a is at the crystallization temperature (usually about
(110° to 180°C), crystallization progresses and shrinks.

After a predetermined period of time has passed, the timer operates and heater 1 is turned off.
9 is deactivated. The above heating time is usually in the range of about 1 to 3 minutes, and depends on the diameter of the mouth and neck 2a, the wall thickness, the hot air temperature,
It is determined as appropriate depending on the desired hardness of the end surface _2a5 .
FIG. 4 shows the state of the vicinity of the mouth and neck region 2a immediately after the heating is completed. The outer circumferential surface 4a ₁ of the core body and the inner circumferential surface 2a ₄ of the mouth and neck are substantially in contact, and the gap d has substantially disappeared. The hot air 8 is discharged from the exhaust hole 17.
Immediately after the heater 19 is deenergized, preferably high-pressure (for example, 1.5 kg/cm ² ) cold air (usually at room temperature) is introduced into the heating cover 7 through the inlet hole 18 . The supply of cold air is continued until the mouth and neck region 2a reaches a temperature below that at which thermal deformation does not occur (usually about 80 to 100° C. or below), and usually takes about 15 to 20 seconds. At the same time as the cold air blowing ends, the rotation of the rotating shaft 13 is stopped and the core lifting device 5 is raised. Due to this rise, the core 4 and the annular body 24 engage with each other, and the top plate of the heating cover 7 engages with the collar 23b of the vertical rod 23, so that the core 4 and the heating cover 7 simultaneously rise, and the core 4 is extracted from the mouth and neck region 2a. Thereafter, the holding plate 14 is opened, the holding device 3 is lowered, and the bottle 2 is taken out from the device 1.

The present invention is not limited to the above embodiments, and the saturated polyester hollow body may be a bottomed parison made of saturated polyester. Further, the mouth and neck portion may be provided with an annular protrusion at the upper end for tightening the metal cap having the peripheral curl portion formed therein.

(Effects of the Invention) The device of the present invention has the following advantages: (a) irregular deformation of the mouth and neck after crystallization is prevented; (b) The core can be easily extracted after crystallization; (c) Only the mouth and neck are crystallized, and the lower part of the mouth and neck is crystallized. The effect is that there is no fear.

[Brief explanation of drawings]

FIG. 1 is a plan view of a device that is an embodiment of the present invention;
Figure 2 is a longitudinal sectional view taken along the - line in Figure 1;
4 and 4 are longitudinal sectional views of the bottle of FIG. 2 in the vicinity of the mouth and neck before and after crystallization, respectively. 1... Crystallization device, 2... Saturated polyester bottle (hollow body), 2a... Mouth and neck, 2a ₄ ... Inner peripheral surface,
3... (hollow body) holding device, 4... core, 4a
...Main body, 4b...Brim section, 4b ₁ ...Bottom surface, 4c...
...Central hole (through hole), 5... Core lifting device, 6...
...Heat shielding member, 7...Heating cover, 8...Hot air,
9...Hot air nozzle, 23a...Sliding pin, 24...
...Annular body (engaging body).

Claims (1)

[Scope of Claims] 1. An apparatus for crystallizing the mouth and neck of a saturated polyester hollow body, the apparatus comprising: a holding device for the hollow body capable of rotating the hollow body around its axis; A main body having an outer diameter smaller than the inner diameter of the mouth and neck by approximately the shrinkage of the inner diameter due to crystallization to the extent that it can be easily extracted from the mouth and neck after crystallization, and the main body is inserted into the mouth and neck. a core made of a heat-resistant resin having a flange having a lower surface that engages with the mouth and neck; a sliding pin that is slidably inserted through a through hole extending in the axial direction of the core; and a lower end of the sliding pin. A lifting device for the core, which is attached to the core and has an engaging body that can engage with the bottom surface of the core, for inserting the core into the mouth and neck before crystallization, and extracting the core from the mouth and neck after crystallization. ; a member for thermally insulating the outside of the mouth and neck and the outside of the lower part of the mouth and neck; a heating cover that houses the mouth and neck during crystallization; and a hot air nozzle that blows hot air into the heating cover. An apparatus for crystallizing saturated polyester hollow bodies, characterized by: 2. The crystallization of a saturated polyester hollow body according to claim 1, wherein the holding device includes a plurality of pressing pieces biased in the radial direction by a spring for holding the lower part of the body of the hollow body. Device.