JPH0541420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for manufacturing a heat-set plastic hollow container, and more specifically, a plastic container whose molecules are biaxially oriented by stretching and heat-set. The present invention relates to a device for efficiently manufacturing in one mold.

(Prior art and its problems) Biaxially stretched blow-molded containers made of thermoplastic polyester such as polyethylene terephthalate (PET) have excellent transparency and surface gloss, as well as the impact resistance, rigidity, and gas resistance required for bottles. It also has barrier properties and is used as bottling containers for various liquids.

However, polyester containers have the disadvantage of poor heat resistance, and when used for hot-filling with contents, they can undergo thermal deformation and shrinkage deformation in volume.・Many proposals have already been made to

Heat setting methods include the so-called one-mold method, in which stretch blow molding and heat setting are performed in one common mold, and the so-called two-mold method, in which stretch blow molding and heat setting are performed in separate molds. The mold method is used.

The former one-mold method includes a method in which heat setting is carried out simultaneously with stretch blow molding in a blow mold, as seen in Japanese Patent Publication No. 59-6216. The problem is that a relatively long residence time in the mold is required for cooling and removal, and the production rate is still low. In addition, as this one-mold method, the temperature of the hollow mold is maintained at as high a temperature as possible, for example, 100°C, within a range that allows the final hollow molded product to be taken out without deformation even without cooling, and It has been proposed to blow high-temperature, high-pressure air into the preform and simultaneously stretch it biaxially (Japanese Patent Application Laid-Open No. 1983-95666).
However, even though this method does not require raising or lowering the temperature of the mold, heat setting by heat transfer from high-temperature gas still requires a relatively long time due to the presence of a heat transfer film. At the same time, the degree of heat shrinkage resistance obtained was still not fully satisfactory.

However, the two-mold method still has a
As seen in the publication, there is a method in which a molded product obtained by stretch blow molding is taken out from a mold blow mold and then held in a heat fixing mold for heat fixing,
As described in Japanese Patent Application Laid-open No. 57-53326, heat treatment is performed simultaneously with stretch blow molding in the primary mold, and the molded product is removed from the primary mold and re-processed in the secondary treatment mold without cooling. Blow molding methods are known.

However, this two-mold method requires two sets of molds, one for molding and one for heat-setting, which increases the equipment cost and increases the number of steps.There are many points that need to be improved.

(Object of the Invention) Accordingly, the object of the present invention is to provide an apparatus capable of continuously manufacturing stretched and heat-set plastic containers in a relatively short period of time occupied in the mold by the one-mold method described above. There is something to do.

Another object of the invention is that the biaxial stretch blow molding of the preform, the heat setting of the hollow molded body and the cooling for removal from the mold can be carried out in a single mold according to a predetermined program with no loss of time. An object of the present invention is to provide an apparatus for manufacturing a heat-setting plastic hollow container that can be effectively carried out without any heat setting.

(Means for Solving the Problems) According to the present invention, there is provided an apparatus for producing stretched and heat-set plastic hollow containers, comprising: a preform made of plastic; and a mandrel supporting the hollow container from the preform; A supply area for placing the preform on the mandrel; a reserve consisting of a turret with a plurality of support seats around the periphery for supporting the mandrel, and a heating mechanism for heating the preform on the mandrel along the outer circumference of the turret. Heating area; Blow molding and heat setting area consisting of a rotating member surrounded by multiple openable/closable blow molding and heat setting molds and mandrel support members corresponding to the molds; Preheating from the preheating area a transfer area for transferring the mandrel on which the preform has been placed is transferred to the blow molding and heat setting area; a take-out area for taking out the mandrel on which the blow molded and heat set container is placed from the blow molding and heat setting area; and the supply area; It consists of an endless transfer path of a mandrel that passes in this order through a preheating zone, a transfer zone, a blow molding and heat setting zone, and a take-out zone. A mold opening/closing mechanism that closes the mold after the mold passes through the feeding area and opens the mold when it reaches the extraction area, and can reciprocate with respect to the preform arranged concentrically with respect to the mandrel. a hollow drawing rod, a first gas passage provided between the periphery of the drawing rod and the mandrel and leading into the preform; a high-pressure hot air supply mechanism and hot air exhaust mechanism that communicate with the first gas passage via an on-off valve or switching valve; and a low-pressure cold air supply mechanism that communicates with the second gas passage via an on-off valve. , and in synchronization with the insertion movement of the stretching rod into the preform, the first gas passage is connected to a high-pressure hot air supply mechanism to carry out stretch blow molding of the preform and trap the hot air in the molding container to release the heat of the container. A control mechanism for an on-off valve that performs fixing and then, after heat fixing, connects a first gas passage to a hot air discharge mechanism and a second gas passage to a cold air supply mechanism to discharge hot air and cool the container. Provided is an apparatus for manufacturing a heat-set plastic hollow container, characterized in that the apparatus is provided with a heat-setting plastic hollow container.

(Function) In the apparatus of the present invention, similarly to known apparatuses, the mandrel that supports the preform and the hollow container during and after stretch blow molding has a preheating zone and a stretch blow molding zone for stretch blow molding. In the stretch blow molding area, a stretch rod and high pressure fluid are inserted into the preform in a mold that is radially attached to the rotating member and is openable and closable. Stretch blow molding of the preform is carried out in collaboration with the blower. However, in the present invention, stretch blow molding of the preform, heat setting of the formed hollow container and cooling of the heat set hollow container for removal from the mold can be carried out in a single mold without any loss time. It is done as an action.

In order to perform this series of operations efficiently, the present invention first uses a mold that is heated to a heat-fixing temperature throughout the entire process of rotation of the mold, and uses high-temperature and high-pressure fluid as the fluid for blow-stretching the preform. Use gas. A hollow container in which the vessel wall has molecular orientation in biaxial directions is formed by stretching the preform in the axial direction using a stretching rod and expanding and stretching it in the circumferential direction by blowing high-temperature and high-pressure gas. Immediately following the molding of this hollow container, The inner surface of the molded container wall contacts the high-temperature, high-pressure gas that is press-fitted into the container, while the outer surface contacts the mold surface heated to a high temperature, thereby thermally fixing the oriented container wall. . At the end of this heat-fixing, the high-temperature, high-pressure gas pressurized inside the container is released, and instead cold air is blown into the container to cool the heat-fixed hollow container for removal. Finally, the mold is opened and the biaxially oriented and heat-set hollow container is removed from the mold without shrinkage or deformation.

According to the present invention, the supply of high-temperature, high-pressure gas and low-pressure cooling gas is controlled as follows. First, a first gas passage leading into the preform is provided between the periphery of the drawing rod and the mandrel, and a second gas passage communicating into the preform through openings distributed in the length direction of the drawing rod is provided inside the drawing rod. A gas passage will be provided. The first gas passage is provided with a high-pressure hot air supply mechanism and a hot air discharge mechanism via an on-off valve or a switching valve, and the second gas passage is provided with a low-pressure cold air supply mechanism via an on-off valve. The control of each on-off valve or switching valve is such that at the start of stretch blow molding, the first gas passage is connected to a high-pressure hot air supply mechanism in synchronization with the insertion of the stretch rod into the preform. The first gas passage is connected to the hot air discharge mechanism, and the second gas passage is connected to the low pressure cold air supply mechanism. That is, first, high-temperature, high-pressure gas is blown into the preform, and not only is the stretch blow molding of the preform performed at an extremely high speed, but also by continuing to apply high-temperature, high-pressure gas into the formed hollow container, Heat setting of the hollow container wall proceeds quickly and efficiently. At the end of heat setting, by connecting the first gas passage between the drawing rod period and the mandrel with a hot air exhaust mechanism, the high temperature and high pressure gas trapped in the container is effectively exhausted, and the drawing rod Cool air is blown uniformly over the entire inner surface of the container through a large number of openings distributed along its length, allowing the heat-set hollow container to be cooled in a short time for removal from the mold. It will be easily done within the next few days.

The invention thus makes it possible to continuously produce stretched and heat-set plastic containers by means of a one-mold process with relatively short mold occupancy times.

(Embodiment) In FIG. 1, which shows the overall arrangement of the apparatus of the present invention as a top view, the apparatus is generally shown as a feeding mechanism (in detail) for feeding a preform 1 made of plastic onto a mandrel 10. will be described later) 30, a preheating mechanism 100 for preheating the preform 1 on the mandrel to the drawing temperature;
A molding heat fixing machine 20 for stretch blow molding and heat fixing a preheated preform in a mold.
0, and a discharge mechanism 40 (details will be described later) for removing and discharging the molded hollow container 20 from the mandrel 10.

A turret-shaped mandrel is provided between the preform introduction side of the preheating mechanism 100 and the hollow container discharge side of the forming heat fixing mechanism 200 for placing the preform 1 on the mandrel 10 and separating the hollow container 20 from the mandrel 10. attachment/detachment mechanism 50 to
is provided. Further, a transfer mechanism 60 for transferring the preheated preform into the mold of the forming heat setting mechanism 200 is provided between the preform discharge side of the preheating mechanism 100 and the preform introduction side of the forming heat setting mechanism 200. It will be done. Further, between the turret-like attachment/detachment mechanism 50 and the preheating mechanism 100, a preform support mandrel transfer mechanism 7 is provided.
Furthermore, a hollow container support mandrel transfer mechanism 80 is provided between the forming heat fixing mechanism 200 and the turret-like attachment/detachment mechanism 50. Thus, the endless transfer path 90 of the mandrel 10 includes the turret-like attachment/detachment mechanism 50, the rider mechanism 70, and the preheating mechanism 10.
0, the transfer mechanism 60, the forming heat-fixing mechanism 200, and the transfer mechanism 80 are formed in this order. In addition, the preheating mechanism 100 and the transfer mechanism 60
Between them are turrets 170 and 18 for keeping the temperature of the preform uniform over time.
0 is provided, and its operation will be described later.

In Figure 2-B showing the preform 1, this preform 1 has a cylindrical shape with dimensions and shape corresponding to the neck of the final container, a neck 2, a cylindrical body 3, a closed bottom 4 and a support. It is equipped with a ring 5 for use. The support ring 5 is provided directly below the mouth and neck part 2.

As shown in FIG. 3, the mandrel 10 has an insertion tip 11 at its tip that is inserted into the mouth and neck of the preform 1, and a cylindrical shaft section 12 below. This cylindrical shaft portion 12 serves as a part for holding a mandrel in various transfer mechanisms, preheating mechanisms, or forming heat fixing mechanisms. In the central part of the mandrel 10, between the two flange parts 13a and 13b, a gear wheel 14 is provided, which serves to rotate the mandrel 10 in the preheating mechanism.
A hollow passage 15 is provided in the center of the mandrel 10, which serves as a space for the elevating and descending movement of the stretch rod in the forming heat setting mechanism and as a fluid passage during stretch blow molding and heat setting operations. It is something. Further, a sealing O-ring 16 is provided at the lower end of the outer circumference of the insertion tip portion 11 for sealingly engaging the tip of the parison neck portion 2.
At the lower end of the cylindrical shaft portion 12, there is an engaging surface 17 that engages with a blow molding lifting member (described in detail later) of the molding heat setting mechanism.

Returning further to FIG. 1, the preform supply mechanism 3
0 consists of a supply chute 31, a small turret 32 and a large turret 33, and the chute 31
has opposing slide plates 34, 34 provided at an interval d that is larger than the diameter of the cylindrical body 3 of the preform 1 and smaller than the diameter of the support ring 5, and the preform 1 is supported in an upright state. It is supplied to the small turret 32 by sliding on the opposing slide plates 34, 34 at the part of the ring 5. The small turret 32 has preform receiving recesses 35 having the above-mentioned spacing d, and supports the preform 1 in the recesses 35 in cooperation with a guide 36, and rotates clockwise in the figure. The large turret 33 also has a preform receiving recess 37 similar to that of the small turret, and supports the preform received from the small turret 32 and rotates counterclockwise along a guide 38. In addition, the small turret 32 and the large turret 33
The circumferential speed of is synchronized with the circumferential speed of the attachment/detachment mechanism 50 to the mandrel.

The attachment/detachment mechanism 50 to the mandrel consists of a rotary body 51 that is driven and rotated in a clockwise direction and a large number (eight in the figure) of clamp mechanisms 52 provided around the rotating body 51 at equal intervals. In FIG. 2-A showing an enlarged view of this attaching/detaching mechanism 50, this clamping mechanism 52 includes a pair of grippers 54, 54 that can be opened and closed and has a notch 53 in the shape of a quarter cylinder at the tip. It consists of an opening/closing drive gear mechanism 55 and a pivot 56 provided at the other end, a bracket 57 that rotatably supports this pivot 56, and a cam follower and gear mechanism 58 for rotating or raising/lowering this bracket 57. There is.

Coaxially with and below the rotating body 51 is a mandrel supporting rotating body 59 having a larger diameter than the rotating body 51.
is provided, and around this rotating body 59,
A mandrel supporting recess 61 is provided corresponding to the clamp mechanism 52. gripper 54,54
When in the closed state, the central axes of the preform supporting notches 53, 53 and the central axis of the mandrel supporting recess 61 are located on the same vertical axis. A magnet 62 is provided in the mandrel supporting recess 61 (see FIG. 2-C), and is capable of attracting and holding the shaft portion 12 of the mandrel 10.

FIG. 2-A shows the clamp mechanism 52 in eight states A to H. Station A is a position where the preform from the large turret 33 is gripped, and in this position, the mandrel 1
0 is held in the mandrel supporting recess 61 by a magnet 62. The grippers 54, 54 are driven by a gear mechanism 55 to close the notch 5.
3 and 53, grip the mouth and neck part 2 of the preform 1. As the clamping mechanism 52 moves from station A to station B, the bracket 57 begins to rotate clockwise by the mechanism 58.
Preform 1 which is clamped along with this
is also rotated. Station B in FIG. 2-A shows a state in which the preform 1 has been rotated approximately 90 degrees. The bracket 57 continues to rotate while the clamp mechanism 52 moves from station B to station C, and the preform 1 is rotated 180 degrees.
That is, the rotation of the preform 1 is stopped in an inverted state. Subsequently, the bracket 57 is lowered by a cam mechanism (not shown), and the preform 1 is pushed into the mandrel 10, which is located on the same vertical axis as the preform 1, in an inverted state. This results in
As shown in FIG. 2-C, the insertion tip 11 of the mandrel 10 is pushed into the mouth and neck of the preform 1, the preform 1 is fixed to the mandrel 10, and the station C is reached.

Station C is a position where the preform support mandrel is transferred to transfer mechanism 70 (FIG. 1). The grippers 54 , 54 are driven open by a gear mechanism 55 to open the preform 1 . In this station C, the mandrel support part 71 of the transfer mechanism, which also includes a magnet, is in close proximity to the preform support mandrel 10, and the attractive force of this magnet acts on the mandrel 10. A mandrel peeling guide 63 is provided on the advancing direction side of the mandrel 10, and moves the mandrel 10 from the attachment/detachment mechanism 50 to the transfer mechanism 70. The operation of the attachment/detachment mechanism 50 after the station C will be described later.

In the embodiment shown in the drawings, the movement of the mandrel between the rotating members is achieved by a combination of magnetic attraction and separation guides, as described above.

The preform preheating mechanism 100 includes a turret 101 that is driven and rotated, and mandrel support seats 1 that are provided at regular intervals around the outer circumference of the turret.
02, an infrared radiation heating mechanism 103 disposed along the outer periphery of the turret, and a drive mechanism 104 (FIG. 4) for rotating the mandrel.

In FIG. 4, which shows an enlarged view of this preheating mechanism, the mandrel 10 supporting the preform 1 is attached to the mandrel support seat 102 by a magnet (not shown).
It is held rotatably by rollers 105. The drive mechanism 104 for rotating the mandrel is composed of a chain, and is engaged with the gear (sprocket) 14 of the mandrel in the range from the most upstream infrared radiant heating mechanism 103a to the most downstream infrared radiant heating device 103z. Thus, as the turret 101 rotates, the preform support mandrel 10 revolves, and the drive mechanism 10
4 is driven, the preform supporting mandrel 10 is rotated.

The infrared radiation heating mechanism 103 extends along the circumferential direction and includes a large number of infrared radiation units 106 arranged at small intervals in the vertical direction. It is attached to the machine frame 107 in a positional relationship that corresponds to the body and bottom. The infrared radiation unit 106 is located on the outer peripheral side of the row of preforms 1, but an infrared shielding plate 110 is provided on the inner peripheral side of the row of preforms 1 via support members 108, 109, and An infrared reflecting plate 112 is also provided above via a support member 111, so that preheating of the preform 1 to the stretching temperature can be performed efficiently.

The preform support mandrel 10 is a transfer mechanism 7
0 to mandrel support seat 1 of preheating mechanism 100
02, and while the preform 1 moves along the infrared radiation unit 106, it also rotates and is preheated to a predetermined temperature. In this case, infrared radiation heating is performed exclusively from the outer surface of the preform 1, so that a temperature gradient is formed in which the outer surface of the preform is relatively high and the inner surface is relatively low. Turrets 170 and 180 are provided to eliminate this temperature gradient and equalize the temperature on the inner and outer surfaces of the preform.

The first temperature equalizing turret 170 includes a mandrel support seat 171, and the second temperature equalizing turret 180 includes a mandrel support seat 181. The mandrel with the preform heated to a predetermined temperature by the preheating mechanism 100 is transferred to the support seat 171 of the first turret 170,
After being kept warm for a certain period of time, it is transferred to the support seat 181 of the second turret 180, and is further kept warm for a predetermined time. Preform 1
The inner surface of the preform 1 is gradually heated to a high temperature due to heat conduction from the outer surface, and the outer surface of the preform 1 is gradually cooled, so that both temperatures become substantially equal. The mandrel with the preform whose temperature has been made uniform is transferred from the mandrel support seat 181 of the second turret 180 to the mandrel support section 65 of the transfer mechanism 60, and further supplied to the forming heat setting mechanism 200.

The molding heat fixing mechanism 200 includes a rotating member 201,
It consists of a split mold 202 that can be opened and closed and is provided around a rotating member so as to be able to rotate together with the rotating member, and a mold opening/closing member 203 (see FIG. 5) that corresponds to the mold. In the circumferential movement path of the split mold, a preform support mandrel transfer zone I, a stretch blow molding heat setting zone J, a cooling zone K, and a container support mandrel takeout zone L are arranged in this order. and the mold 202 in the heat setting zone J and the cooling zone K.
is closed, but the mold 202 is closed in other areas.
is open.

In FIG. 5 showing details of the molding heat fixing mechanism 200, the rotating mechanism 201 includes a mold opening/closing arm 206.
are fixed in a radial manner, and a vertical shaft 205 is fixed to the support portion thereof. A mold opening/closing arm 206 is provided so as to be able to swing horizontally about this vertical axis 205.
A split mold 202 is attached to one end of the
A fluid pressure cylinder 207 for driving the split mold 202 to open and close is provided at the other end. The split mold 202 has a cavity 20 with dimensions and shape corresponding to the final container shape supported by the mandrel.
8 is provided.

A mandrel support bracket 209 is secured below the vertical shaft 205. Bracket 2
There is a mandrel support seat 210 above the tip of the mandrel 10, and a magnet 211 for holding the shaft portion 12 of the mandrel 10 is provided on this support seat 210. A housing portion 213 is provided below the tip of the bracket 209 to support a blow molding lifting member 212 so as to be movable up and down. The blow molding lifting member 212 has a sealing surface 214 to be sealingly engaged with the lower end surface of the mandrel 10,
It has a vertically extending passageway 215 therein. The blow molding lifting member 212 is always urged downward by a push spring 216, and is raised by the operation of the electromagnetic valve 245 shown in FIG. A stretching rod 217 is provided in the passage 215 of the blow molding lifting member 212 so as to be movable up and down.
This lifting rod 217 is also driven by the solenoid valve 2 in FIG.
This is done by the operation of 47.

There is a gap serving as a gas passage between the passage 215 of the blow molding lifting member 212 and the stretching rod 217, and this passage is connected to a gas source via a passage 218. Further, the stretching rod 217 and the blow molding lifting member 212 are sealed with a seal 219.

A bottom mold 221 is provided above the vertical shaft 205 by means of a support 220 so as to be movable up and down by means of an elevating shaft 222 . The lifting shaft 222 is driven by the support 220
This is done by a bottom-type lifting fluid cylinder 223 provided in the.

When the split mold 202 is closed, the center of the cavity 208, the center of the bottom mold 221, and the support seat 21
The center of the mandrel 10 supported at 0, the center of the blow molding lifting member 212, and the stretching rod 217 are all aligned so that they are located on the same vertical axis. The extension rod 217 includes an engagement tip 224 . The stretching rod 217 is connected to the passage 15 of the mandrel 10.
The engagement tip 224 is inserted into the preform 1 through the interior thereof, and the engagement tip 224 engages with the bottom inner wall of the preform 1, allowing the preform 1 to be stretched in the axial direction.

In FIG. 6, which shows the cross-sectional structure of the drawing rod in relation to the mandrel, in the passage 15 of the mandrel 10, around the drawing rod 217, there is a first gas passage 226 leading to the interior space 225 of the preform or container. It is provided. This first gas passage 226 passes through the passage 215 of the lifting member and passes through the passage 2
18. The drawing rod 217 is hollow and is provided with a second gas passage 227, which is inserted into the interior space 225 of the preform or container through openings 228 distributed along the length of the drawing rod. is familiar with The first gas passage 226 is connected to a high-pressure hot air supply mechanism and hot air/cold air discharge mechanism, which will be described later, via an on-off valve or switching valve, while the second gas passage 227 is connected to a low-pressure cold air supply via an on-off valve. connected to the mechanism.

In the apparatus of the present invention, first, the surface temperature of the cavity 208 of the mold 202 is heated through the entire rotation process of the mold by an electric heating mechanism 229 provided in the mold 202 to a heat-fixing temperature. There is.

In FIG. 7 showing the control mechanism of the blow molding heat fixing mechanism 200, C is a check valve and R is a rotary joint. High pressure air source (e.g. up to 40Kg/
cm ² ) 230 is separated into a relatively high pressure blowing air source 232 via a pressure reducing valve 231 and a relatively low pressure cooling air source 234 via a pressure reducing valve 233. A high pressure blowing air source 232 is connected to a rapid heating tank 236 equipped with an electric heating mechanism 235. The rapid heating tank 236 is connected to the blow solenoid valve 2.
39 to the first gas passage 226. Further, the first gas passage 226 is connected to an exhaust port 241 via an exhaust electromagnetic valve 240.

A low pressure cooling air source 234 is connected to the second gas passage 227 via a container cooling solenoid valve 242 .

Separately from the high-pressure air source, a low-pressure air source 243 for driving each fluid cylinder is provided.
44 and to each fluid cylinder via a rotary joint _R2 . That is, the stretching solenoid valve 24 is connected to the lifting cylinder 246 of the lifting member for blow molding via the mandrel sealing solenoid valve 245.
7 to the elevating cylinder 248 of the stretching rod;
The bottom mold lifting cylinders 223 are connected to the bottom mold lifting cylinders 223 via bottom mold solenoid valves 249 .

Further, the mold opening/closing cylinders 251 are each connected to a cylinder driving low pressure air source 243 via an opening/closing solenoid valve 255.

In addition, in order to improve the separation of the heat-fixing container from the bottom mold 221, the bottom mold 221 is connected to the air blowing pipe 2.
56, and this piping 256 is connected to a high-pressure blowing air source 232 via a mold release solenoid valve 257.

Blow molding and thermal processing are performed by the following operations.

(1) Supply At station I in Figure 1, the mold 202
is in an open state, the bottom mold 221 is in the lowered position, and the blow molding lifting mechanism 212 is also in the lowered position. A mandrel 10 with a preform preheated to the drawing temperature is held on a mandrel support seat 210.

(2) Preparation for molding The mold opening/closing solenoid valve 255 switches, the mold opening/closing cylinder 251 moves to the closing stroke, and the mold 20
2 closes. Next, solenoid valve 2 for mandrel seal
45 is switched, the lifting cylinder 246 raises the blow molding lifting member 212, and the mandrel 1
Maintains a sealed state with 0.

(3) Blow molding and heat fixing At station J in Figure 1, the solenoid valve 247 for stretching
is turned on, the cylinder 248 moves upward, and the stretching rod 217 rises to stretch the preform 1 in the axial direction.

At the same time, the electromagnetic valve 239 is switched and high-temperature, high-pressure air is blown into the preform through the first passage 226, thereby expanding and stretching the preform in the circumferential direction.

The mold 202 is heated to a fixed temperature, and the vessel wall with biaxially oriented molecules is heated to a fixed temperature.
contact with the cavity surface and heat fixation takes place.
Furthermore, high temperature and high pressure air remains applied to the inside of the container 20 via the first passage 226, and the container 20
Heat fixation of 0 occurs quickly.

(4) Cooling The stretch blow-molded container 20 heat-set in the mold 202 for a predetermined time at the station K in FIG.
Cooling is performed for removal from the mold. First of all,
The blow solenoid valve 239 switches to cut off the circuit,
The exhaust solenoid valve 240 opens, and the container cooling solenoid valve 2 opens.
42 is open. As a result, as shown in FIG.
8 onto the molecularly oriented and heat-set containers. The high temperature air trapped in the space 225 inside the container and the cooling air blown onto the container wall are transferred to the first gas passage 226 around the stretching rod.
and is quickly discharged to the outside through the exhaust port 241.

(5) Removal The container, which has been cooled to the extent that deformation of the container wall is prevented, is finally removed from the mold at station L in Figure 1. First, the container cooling solenoid valve 242 is closed, then the mandrel sealing solenoid valve is switched, and the blow molding lifting member 212 is returned to the lowered position by the spring 216 (see FIG. 5). Immediately after, the mold opening/closing solenoid valve 255 and the stretching solenoid valve 247 are switched, the cylinder 251 is activated to open the mold, and the cylinder 248 is activated to lower the stretching rod 217.
Stop at the position shown in Figure 5. In this case, it is desirable that cooling from the inside of the container in step 4 continues at least until the mold is about to open. Next, the exhaust solenoid valve 240 is closed.

The bottom mold solenoid valve 249 is switched, and the cylinder 2
23 is operated to raise the bottom mold 221.
At the same time, the mold release solenoid valve 257 is switched, and high pressure air is blown onto the bottom of the container to smoothly release the mold.

In the take-out area L shown in FIG. 1, a mandrel 10 with a stretched and heat-set container 20
is transferred to the transfer mechanism 80 and supplied to the attachment/detachment mechanism 50 to the mandrel.

Returning again to FIG. 2-A, clamping mechanism 52 at station C, with grippers 54, 54 in the open position, passes stations D and E to station F for receiving a container support mandrel. That is, at the station F, the container support mandrel 10 is supported by the mandrel support recess. The grippers 54, 54 are driven to close and grip the neck 2 of the container 20 with the cutouts 53, 53. As the station moves from station F to station G, the clamp mechanism 52 moves upward, thereby causing the container 20 to move toward the mandrel 10.
separated from

In FIG. 1, the ejection mechanism 40 of the container 20 is
It consists of a container reversing mechanism 41 and a container transport mechanism 42. The container reversing mechanism 41 is for uprighting an inverted container, and is similar to the clamping mechanism shown in FIG. 2-A, except that it does not have a mandrel support mechanism.

In FIG. 8 showing this container reversing mechanism, the rotating body 43 has a large number of clamp mechanisms 52A around it, and each member of the clamp mechanism 52A has the same reference numeral as each member in FIG. 2-A. It is shown with an A attached to it. The container reversing mechanism 41 has 6
There are three stations M-R. Station M
is the container clamp position, which corresponds to the station G of the attachment/detachment mechanism 50. That is, in the station G of the attachment/detachment mechanism 50, while the grippers 54, 54 are still closed, the grippers 54A, 54A of the reversing mechanism 41 close and grip the lower part of the support ring 5 of the container 20. Next, the grippers 54, 54 of the attaching/detaching mechanism 50 are opened, and the container 20 is transferred to the reversing mechanism 41.

At the station M of the reversing mechanism 41, the container 20 is in an inverted state. Then, as the reversing mechanism 41 rotates counterclockwise, the bracket 57A begins to rotate clockwise. At station N, the container 20 is rotated approximately 90 degrees, and at station O, the container 20 is rotated 1180 degrees and is in an upright position. At this station O, grippers 54A, 5
4A opens and releases the container 20 onto the transfer conveyor 42, which transports the container 20 to a work area such as inspection and packaging. The clamp mechanism 52A is connected to the station P,
As it passes Q and R, it rotates another 180 degrees,
Reach station M.

In FIG. 9 showing an example of a stretched heat-fixed hollow container manufactured by the apparatus of the present invention, this container 20 is
Suitable for hot filling of beverages such as fruit juice, vegetable juice, and tea.
It is a PET bottle, and includes a threaded neck part 2, a support ring 5, a conical shoulder part 21, a tapered upper body part 23 connected to the shoulder part via a circumferential step part 22, a circumferential recessed part 24 in the upper part of the body, and It consists of a trunk lower part 26 and a bottom part 27 that are connected via a circumferential convex part 25.
The lower body part 26 has a relatively large diameter and a short circumference,
A large number of protrusions 28 extending in the height direction and panel-shaped recesses 29 having a relatively small diameter and a long circumference are provided alternately in the circumferential direction.

The panel-shaped recess 29 expands outward when the internal pressure increases and contracts inward when the internal pressure decreases, thereby having the effect of alleviating changes in internal pressure. Convex part 2
5 has the function of allowing slight deformation in the axial direction of the container. Furthermore, there is a star-shaped inward concave portion 27A in the center of the bottom portion 27, which has the function of preventing outward buckling due to pressure or thermal deformation.

According to the present invention, each of these parts of the container is effectively heat-fixed, and thermal deformation of these parts during hot filling is effectively prevented, so that the functions of each part are maintained during hot filling and thereafter. It is maintained even after cooling and aging, and prevents unsightly irregular deformation of the container.

Although the apparatus of the present invention can be used to produce a variety of stretched heat-set plastic containers, it can be advantageously applied to the production of stretch-set plastic containers made of thermoplastic polyester.

In the present invention, the thermoplastic polyester is a thermoplastic polyester mainly containing ethylene terephthalate units, such as PET, containing a small amount of other glycols such as hexahydroxylene glycol as a glycol component, or isophthalic acid as a dibasic acid component. So-called modified PET containing a small amount of other dibasic acid components such as hexahydroterephthalic acid and the like is used. These polyesters can be used alone or in the form of blends with other resins such as nylons, polycarbonates, or polyarylates.

The intrinsic viscosity of the thermoplastic polyester used is 0.67
dl/g or more and the content of diethylene glycol units is preferably 2.0% by weight or less.

The bottomed preform used in stretch blow molding is manufactured by any method known per se, such as injection molding, pipe extrusion molding, and the like. In the former method, molten polyester is injected to produce a bottomed preform in an amorphous state with a neck and neck corresponding to the final container. The latter method is advantageous for producing a bottomed preform with a gas barrier intermediate resin layer such as ethylene-vinyl alcohol copolymer, and involves cutting an extruded amorphous pipe,
While forming a mouth and neck part by compression molding on one end,
The other end is closed to form a bottomed preform. In order to maintain good engagement with the lid and sealing under high temperatures, only the portion that will become the mouth and neck of the container can be thermally crystallized in advance. Of course, this thermal crystallization may be carried out at any subsequent stage.

The preheating temperature of the preform is generally in a temperature range called the stretching temperature, and in the case of PET, it is in the temperature range of 80 to 120°C, particularly 90 to 110°C. The present invention is an apparatus that can be advantageously applied to high-speed stretch forming and heat setting of preforms. In this case, since the inner surface of the preform has a higher stretching ratio than the outer surface, the temperature of the inner surface of the preform is higher than that of the outer surface. The temperature difference between the two is preferably within 10°C, particularly preferably within 5°C.

In the present invention, the temperature of the mold is such that the biaxially stretched container is effectively heat-set. This temperature largely depends on the degree of heat resistance required for the container, but it is desirable to be as high as possible within a range that allows the container to be taken out without deformation in a relatively short cooling time, and is generally 100% From 180℃ to 180℃, especially
It is desirable that the temperature be within the range of 120 to 150°C.

As the high-temperature, high-pressure blowing air, air heated to a higher temperature than the preform temperature is used.
In terms of high-speed stretching and heat-setting efficiency, it is advantageous to use air at a temperature of 100 to 150°C, particularly 110 to 140°C. In addition, the pressure is 10 to 50Kg/cm ² (gauge),
In particular, it is desirable that the weight is within the range of 25 to 30 kg/cm ² (gauge) from the viewpoint of high-speed stretchability and heat-setting efficiency.

As cooling air, use room temperature air for 10 to 30 minutes.
Kg/cm ² (gauge), especially 15 to 25Kg/cm ² (gauge)
Supplied at a pressure of

The stretching ratio is 1.2 to 3.0 times the axial stretching ratio,
Especially 1.5 to 2.5 times, circumferential stretching ratio 2 to 5
It is preferable to increase the amount by 2.5 times to 4.5 times.

Biaxially stretched and heat-set hollow containers using the apparatus of the invention can be produced using a single mold and with relatively short dwell times in the mold. By way of example, the stretch blow molding time in the mold is generally 0.5 to 3 seconds, especially 1 to 2 seconds, the heat setting time is 3 to 15 seconds, especially 4 to 8 seconds, and the cooling time is 3 to 15 seconds, especially 4 to 8 seconds. It is on the order of seconds.

In the present invention, the axial stretching speed is increased to 2.5 times/
High-speed stretching of the parison at a speed of 2 seconds or more, especially 3.0 times/second or more, and a circumferential stretching speed of 4.5 times/second or more, especially 5.0 times/second or more, reduces the internal friction of the preform. Desirable for effective use.

(Effects of the Invention) According to the apparatus of the present invention, it is possible to efficiently produce a heat-set container that has been biaxially stretched by a one-mold method in a short mold occupation time.

In addition, the temperature of the preform is relatively high, and hot air at a temperature higher than that of the preform is injected into the preform, making high-speed stretch blowing possible. There is self-heating generated by the preform, which raises the temperature of the preform being stretch-blow-molded to a higher temperature, promoting strain relaxation and crystallization, and heat setting is efficiently performed within a short time.

The maximum temperature at which a stretch-blown container heat-set by the one-mold method can be taken out without substantial deformation is:
There is a tendency for the temperature to increase as the heat setting temperature increases. In the present invention, as described above, heat fixation is carried out at a relatively high temperature, and the switching from heat fixation operation to cooling operation is also carried out extremely quickly without loss time, so the time required to cool the heat fixation container is also significantly shortened. This gives you the advantage of being able to do so.

[Brief explanation of the drawing]

Fig. 1 is a top view showing the overall arrangement of the device of the present invention, Fig. 2-A is an enlarged top view showing the attachment/detachment mechanism to the mandrel, and Fig. 2-B is a side view showing the preform. 2-C is a side view showing the mandrel into which the preform is inserted, FIG. 3 is an enlarged side sectional view of the mandrel, and FIG. 4 is an enlarged side sectional view showing the preheating mechanism. FIG. 5 is an enlarged side cross-sectional view showing the forming heat-setting mechanism, FIG. 6 is an enlarged cross-sectional view showing the cross-sectional structure of the drawing rod in relation to the mandrel, and FIG. FIG. 8 is a system diagram showing the control mechanism of the blow molding heat fixing mechanism, FIG. 8 is an enlarged top view showing the container reversing mechanism, and FIG. 9 is a front view showing an example of the container manufactured by the apparatus of the present invention. It is. 1... Preform, 10... Mandrel, 3
0... Supply mechanism, 100... Preheating mechanism, 20
0... Molding heat fixing mechanism, 20... Molding hollow container,
40... Discharge mechanism, 50... Detachment mechanism, 202...
...Split mold, 217...Stretching rod, 226...First gas passage, 227...Second gas passage, 229...
...Electric heating mechanism, 236... Rapid heating tank, 230
... High pressure air source, 232 ... Blow air source, 2
34... Cooling air source, 239, 242, 24
5,247,249,255...Valve, 223,2
46,248,251...Fluid cylinder.

Claims (1)

[Scope of Claims] 1. An apparatus for producing stretched and heat-set plastic hollow containers, comprising: a preform made of plastic and a mandrel for supporting the hollow container from the preform; a supply area for placing the preform on the mandrel; a preheating zone consisting of a turret with a plurality of support seats around the periphery for supporting the mandrel and a heating mechanism for heating the preform on the mandrel along the outer periphery of the turret; a plurality of openable and closable blows; A blow molding and heat setting area consisting of a rotating member surrounding a mold for molding and heat setting and a mandrel supporting member corresponding to the mold; a transfer zone for transferring to the blow molding and heat fixing zone; a take-out zone for taking out the mandrel on which the blow molded and heat fixed containers are placed from the blow molding and heat fixing zone; and the supply zone, preheating zone, transfer zone, blow molding. The blow molding and heat setting area includes: a mold which is heated to the heat setting temperature throughout the entire process of rotation; A mold opening/closing mechanism that closes the mold after passing the mandrel and opens the mold when it reaches the ejection area; A hollow drawing rod that can reciprocate with respect to the preform arranged concentrically with respect to the mandrel; a first gas passage provided between the periphery and the mandrel and leading into the preform; a second gas passage provided inside the drawing rod and communicating into the preform through openings distributed along the length of the drawing rod; A high-pressure hot air supply mechanism and a hot air discharge mechanism that communicate with the first gas passage via an on-off valve or a switching valve, a low-pressure cold air supply mechanism that communicates with the second gas passage via an on-off valve, and insertion of a stretching rod into the preform. In synchronization with the movement, the first gas passage is connected to a high-pressure hot air supply mechanism to carry out stretch blow molding of the preform and to trap the hot air in the molding container to heat set the container. A control mechanism for an on-off valve is provided which connects one gas passage to a hot air discharge mechanism and connects a second gas passage to a cold air supply mechanism to discharge hot air and cool the container. Equipment for producing heat-set plastic hollow containers.