JPS6255966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a parison temperature control method and apparatus.

When molding hollow containers from synthetic resin materials such as polyethylene terephthalate and polypropylene,
First, a parison is formed, heated to a predetermined temperature, and then stretch-blown blow molding is performed. In the conventional parison temperature control method, the parison is cooled down in the injection mold during injection molding, the parison temperature is lowered to below the stretch blow blow molding temperature, the parison is taken out, and then the parison temperature is lowered to the stretch blow blow molding temperature in the parison heating furnace. The temperature was rising so that For this reason, the injection molding time becomes longer by the amount of cooling time required, which poses the problem of poor productivity, and the problem of large energy loss as the temperature of the once-cooled parison must be raised again.
In order to deal with this problem, the cooling time during injection molding is shortened, and the molded parison is taken out with a large temperature difference in the longitudinal direction and wall thickness direction, and the parison is uniformly stretched and blown in the parison heating furnace. It took a long time to adjust the temperature to the blow molding temperature, and the problem was not solved in the end.

In the method of the present invention, the parison is removed from the mold before the temperature of the injection-molded parison falls below the stretch blow blow molding temperature, and the parison is placed in an air blowing chamber that surrounds the entire parison, and the air blowing chamber is filled with temperature-controlled air. is blown into the parison to uniformly adjust the temperature of the entire parison, and then the parison is transferred to a parison heating furnace to raise the temperature of the parison to the stretch blow blow molding temperature. Furthermore, the apparatus of the present invention for carrying out the method of the present invention reciprocates between the inside and outside of a mold clamping device to which an upper injection mold and a lower injection mold for parison molding that receive the molten resin from the injection device are attached. A movable table, a parison support plate provided at the top of the mobile table, a parison support hole provided in the parison support plate to a size that can support the neck part of the parison, and a parison supported by the parison support hole. A cylindrical member attached to the lower surface of the parison receiving plate so as to surround the cylindrical member, an exhaust hole provided in the upper part of the cylindrical member that penetrates the inner and outer diameters, and a cylindrical member when the movable table is stopped at the stop position on the outside of the mold clamping device. An air jet pipe installed at a lower position, a blower and an air temperature control device capable of supplying temperature-controlled air to the air jet pipe, and a parison that is taken out from inside the cylindrical member of the moving platform and transferred. It has a parison heating furnace.

Hereinafter, the present invention will be explained based on FIGS. 1 and 2 of the accompanying drawings.

The first and second apparatuses for carrying out the method of the present invention are
As shown in the figure. A mold clamping section 4, a first parison temperature regulating section 6, and a second parison temperature regulating section 8 are arranged on the bed 2. In addition, the second parison temperature control section 8
The portions below the stretch hollow molded portion following 2 are omitted from illustration. The mold clamping section 4 includes a mold clamping device 10 and a mold clamping device 10
It has an upper injection mold 12 and a lower injection mold 14 attached to the mold. Molten resin can be injected into the upper injection mold 12 and the lower injection mold 14 from an injection device 15. The first parison temperature control section 6 is provided with a moving table 16, and the moving table 16 runs on a horizontal running path 18 provided between the mold clamping section 4 and the first parison temperature control section 6. can do.
A piston rod 20a of an air cylinder 20 is connected to the moving table 16, and the moving table 16 adjusts the temperature of the first parison temperature controller 6 by the operation of the air cylinder 20.
and the mold clamping part 4. The parison support plate 22 on the top surface of the moving table 16 has a parison support hole 26 that can support the neck portion of the parison 24.
is provided. A cylindrical member 28 is attached to the lower surface of the parison receiving plate 22 so as to surround the parison 24 inserted into the parison support hole 26. The cylindrical member 28 has an exhaust hole 30 at the top. This cylindrical member 28 constitutes an air blowing chamber. An air ejection pipe 32 is provided at the lower part of the first parison temperature control section 6. This air ejection pipe 32 is arranged so as to be directly below the cylindrical member 28 when the movable table 16 stops at the first parison temperature control section 6. Temperature-controlled air can be supplied to the air jet pipe 32 by a blower 34 through an air temperature control device 36 . Second
The parison temperature adjustment section 8 is provided with a parison heating furnace 38 that can heat the parison 24 with a heater.

Next, a method of adjusting the temperature of the parison using the apparatus shown in FIGS. 1 and 2 will be described. An injection device 1 is installed in the upper injection mold 12 and the lower injection mold 14.
When the molten resin is injected from 5 and the parison is molded, the upper injection mold 12 is raised. Upper injection mold 12
At the same time, the movable table 16 moves from the position of the first parison temperature control section 6 to the right in FIG.
It comes to the bottom of 2. The parison 24 is then ejected into the parison support hole 26 of the parison receiving plate 22.
Supported by. Then air cylinder 2 again
0 moves the moving table 16 to the left in FIG. 1 and returns to the position of the first parison temperature control section 6. The moving table 16 is the first parison temperature control section 6
Immediately after stopping, air at a predetermined temperature is ejected from the air ejection pipe 32. A blower 3 is installed in the air jet pipe 32.
4 supplies air whose temperature is adjusted to a predetermined temperature through an air temperature adjustment device 36. Air ejected from the air ejection pipe 32 enters the inside of the cylindrical member 28 and is exhausted from the exhaust hole 30. That is, the inside of the cylindrical member 28 is always filled with air at a predetermined temperature. The temperature of the parison 24 is controlled by this air at a predetermined temperature. Next, after a predetermined period of time has elapsed, the parison 24 is transferred into the parison heating furnace 38 of the second parison temperature control section 8 by a gripper device (not shown). Parison heating furnace 38
Inside, the parison 24 is adjusted to the stretch blow blow molding temperature. When the parison 24 is adjusted to the stretch blow blow molding temperature, the parison 24 is sent to the stretch blow blow molding section by a clipper device (not shown), and stretch blow blow molding is performed. A hollow molded product is thereby obtained. Note that the movement of the parison 24 from the first parison temperature control section 6 to the second parison temperature control section 8 and the movement of the parison 24 from the second parison temperature control section 8 to the stretch blow molding section are performed simultaneously. Therefore, the time required for temperature adjustment by the air adjusted to a predetermined temperature in the first parison temperature adjustment section 6 is approximately half the time for heating the parison 24 in the second parison temperature adjustment section 8.

As mentioned above, before inserting the parison 24 into the parison heating furnace 38, temperature-controlled air can be blown onto the parison 24 to reduce the temperature difference between each part of the parison 24 and to equalize the temperature.
There is no need to cool down during injection molding to reduce temperature unevenness. Therefore, injection molding time can be shortened and efficiency can be improved. Further, the parison 24 is taken out from the injection molds 12 and 14 at a temperature higher than the stretch blow blow molding temperature, and after being equalized with temperature-controlled air, the parison is heated in order to adjust the temperature in the parison heating furnace 38. Furnace 3
The parison temperature adjustment at 8 is facilitated, and energy losses are also reduced since little reheating of the parison is required. As explained above, the temperature of the air ejected from the air ejection pipe 32 is determined by taking out the injection molded parison at a temperature equal to or higher than the stretch blow blow molding temperature, and then injecting air at a predetermined temperature into the parison. Since the parison is then adjusted to the stretch blow blow molding temperature in a heating furnace, the time required for injection molding and parison temperature adjustment can be shortened, shortening the cycle time and improving productivity. Since the temperature can be adjusted without cooling the parison, energy loss can be reduced. In addition, the device of the present invention for carrying out the method of the present invention has a simple structure in which temperature-controlled air is jetted into a cylindrical member from an air jet pipe, and the cost is lower than that in the case where a parison heating furnace is provided. be able to. Furthermore, when changing the shape of the parison, it is sufficient to simply change the shape of the parison receiving plate, and the costs associated with changing the shape can also be reduced.

[Brief explanation of the drawing]

FIG. 1 shows an apparatus for carrying out the method of the invention. Figure 2 shows the equipment shown in Figure 1.
It is a sectional view along a line. 2... Bed, 4... Mold clamping section, 6... First parison temperature control section, 8... Second parison temperature control section, 10... Mold clamping device, 12... Injection upper mold, 1
4... Injection lower mold, 15... Injection device, 16...
Moving table, 18... Running path, 20... Air cylinder, 22... Parison receiving plate, 24... Parison, 26... Parison support hole, 28... Cylindrical member, 30... Exhaust hole, 32... Air spout pipe, 34
...Blower, 36...Air temperature control device, 38...
...Parison heating furnace.

Claims (1)

[Claims] 1. In a parison temperature adjustment method for adjusting an injection molded parison to a stretch blow blow molding temperature, the parison is removed from the mold before the temperature of the injection molded parison falls below the stretch blow blow molding temperature. The parison is then placed in an air blowing chamber that surrounds the entire parison, and temperature-controlled air is blown into the air blowing chamber to uniformly adjust the temperature of the entire parison.Then, the parison is transferred to a parison heating furnace and the temperature of the parison is stretched and blown. A parison temperature control method characterized by raising the temperature to a blow molding temperature. 2. A movable table capable of reciprocating between the inside and outside of the mold clamping device to which the upper and lower injection molds for parison molding that receive molten resin from the injection device are installed, and a movable table provided on the top of the movable table. a parison support plate provided with a parison support plate having a size that is large enough to support the neck portion of the parison; and a parison support hole that is attached to the lower surface of the parison support plate so as to surround the parison supported by the parison support hole. a cylindrical member; an exhaust hole provided at the top of the cylindrical member passing through the inner and outer diameters; an air ejection pipe provided at a lower position of the cylindrical member when the movable table stops at a stop position outside the mold clamping device; It is characterized by having the following: a blower and an air temperature control device capable of supplying temperature-controlled air to the ejection pipe; and a parison heating furnace that heats the parison taken out from inside the cylindrical member of the moving table and transferred. Parison temperature control device.