JPH03222714A - Molding device for blow molding - Google Patents

Abstract

PURPOSE:To shorten the molding cycle by making effective use of sensible heat brought-in by gas heating and cooling the inside of a parison, by a method wherein a gas introducing pipe introducing gas heating or cooling the inside of the parison and a gas discharging pipe discharging the gas at the time of molding are fitted to a mold by separating them from each other. CONSTITUTION:A surface part region 20 of a mold is heated beforehand by a heating medium and the same is heated and supported by a radiant tap controlled heater 60. At a point of time when a parison 2 is extruded and both molds 3, 4 are mold- registered, a gas discharge pipe 103b and gas introducing pipe 103a are moved forward into an insertion through hole provided into the female mold 4, the front end parts of which are entered within the parison 2 and gas is discharged continuously through the gas discharge pipe 103b while introducing heating medium through the gas introducing pipe 103a. Furthermore, high-speed heating and high-speed cooling become possible by a method wherein cooling of the surface part region of the mold is performed by changing over from the heating medium to a cooling medium and also the parison is molded and solidified by changing over from heating blowing air to cooling blowing gas. The gas introducing pipe 103a and gas discharging pipe 103b are separated from each other as much as possible and a pressure control valve is provided on an outlet side of the discharging pipe 103b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a molding apparatus for blow-molded synthetic resin articles.

[Prior Art] The blow molding method is also called the block molding method or the blow molding method, and is a very convenient molding method for making hollow products such as Blastifuku bottle containers.

Other examples of products made using blow molding machines include various tanks.

The range of applications has expanded in recent years, including cases, containers, automobiles, and various structural components related to leisure.

Figure 4 is a patent application published in Japanese Patent Application No. 63-23984, which was not yet known before the filing date of the present application.
FIG. 5 is a partially cutaway sectional view of a syringe, and the prior art will be explained with reference to FIGS. 4 and 5. FIG.

The molding device shown in FIG. 4 includes a die 1, a male mold 3.
Female mold 4. Radiant instant heater 60 and gas injector 10
Consists of 0.

The male mold 3 and the female mold 4 have a mold surface region 20 made of a good thermal conductor such as an An alloy or a Cu alloy arranged on the mold surface, and a middle region of the mold with a low thermal conductivity. It consists of an intermediate layer 30 filled with non-metal, resin, etc., a mold frame 40 and a buckle plate 50 that form the mold. Further, in the mold surface area 20, a large number of holes are arranged at approximately regular intervals for the purpose of introducing a heating medium for heating the surface of the parison 2 during molding and a cooling medium for solidifying the parison 2 after molding. It has a through hole 21, which allows rapid heating or rapid cooling of the mold surface area 20. Also,
The conduction holes 21 or 22 provided in the mold described above are appropriately connected to a mold temperature controller (not shown) via piping 51.

Furthermore, as shown in FIG. 4, a radiant instantaneous heater 60 using near-infrared rays (for example, a rod-shaped near-infrared halogen lamp manufactured by Philips Corporation attached to the surface of the heating container) is used to heat the mold surface area. By heating the surface of the parison 20 as well as the surface of the parison 2 hanging down from the die 1, it is possible to heat each resin evenly in a short time to the softening point.

Next, the operation of the molding die device will be explained.

Now, a heating medium is introduced into the through hole 21 of the mold surface area 20 from the mold temperature controller (not shown in FIG.
0 is advanced and inserted between the male mold 3 and the female mold 4 which are at the full mold open limit position, and the surfaces 3a and 4a of both mold surface areas 20 are heated for a certain period of time to a temperature of 90 to 200 ℃, and when both mold surfaces 3a and 4a reach the desired temperature, the radiant instantaneous heater 60 is retreated and returned to its original position. Next, the parison 2 is hung down from an extruder (not shown) through a die 1, and the tip of the parison 2 is brought into close contact with a contact jig (not shown) to form a bag shape.
and the female mold 4 are moved so that they are close to each other, and the parison 2 is sandwiched between the male mold 3 and the female mold 4, and at the same time,
Double tube type or double tube type syringe 1 as shown in Fig. 5
The tip of the 00 is inserted into the parison 2 formed by both the male mold 3 and the female mold 4, and the parison 2 is brought into closer contact with both molds by blowing heated blowing air. . At this time, in the case of a double pipe type, the gas introduction pipe part 10 of the inner pipe
The heated plow air introduced from 1 is continuously discharged from the gas discharge pipe section 102 of the outer tube of the injector 100.

After the male mold 3 and female mold 4 are clamped, a cooling medium is introduced from the mold temperature controller into the through hole 21 of the mold surface area 20 to cool the mold surface area 20, and the gas The heated blowing air blown from the gas introduction pipe 101 of the injector 100 is switched to low-temperature blowing gas to cool the parison 2 from inside, and after a certain period of time, the low-temperature blowing gas is blown into the parison 2. Stop filling, open both molds and take out the molded product.

[Problem to be solved by the invention] However, it is difficult to smoothly apply heating and cooling from inside the parison by using a conventional injector with a double-tube type gas inlet pipe and gas discharge pipe. In this case, part of the heating or cooling air introduced into the parison from the gas inlet pipe at the tip of the injector may be exhausted from the adjacent gas exhaust pipe without effectively utilizing the heat. As a result, it is difficult to form a smooth forced flow of gas with good thermal efficiency inside the parison, and the tip of the gas injector may become clogged when penetrating the parison that is drooped and clamped. It had the following drawbacks.

[Means for Solving the Problems] In order to solve these problems, the present invention provides a gas introduction pipe for introducing heating or cooling gas into the inside of the parison between the fixed mold and the movable mold during molding. The gas exhaust pipes for discharging the introduced gas were attached to the mold at a distance from each other.

[Function] According to the present invention, first, the surface area of the mold is preheated with a heating medium, and the surface area of the mold is heated to a desired temperature of 90 to 200° C. by heating with a radiant instant heater. Next, extrude the parison from the die and let it hang down 1
When the two molds are combined, the gas injector for the gas inlet pipe and the needle for the gas discharge pipe are separated from each other in the female mold and installed in the designated positions, and then the heating medium is introduced from the gas injector for the gas inlet pipe. , the gas is continuously discharged from the gas discharge pipe. Furthermore, by switching from a heating medium to a cooling medium, the mold surface area is cooled, and the parison is also switched from heating blowing air to cooling blowing gas to form and solidify the parison, enabling high-speed heating and cooling. As a result, the molding cycle can be shortened and molded products with excellent transferability can be produced.

[Example] Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 3 show one embodiment of a mold apparatus for forming a hollow molded product according to the present invention.

FIG. 1 is a perspective view of a mold apparatus, FIG. 2 is a vertical cross-sectional view of the mold, and FIG. 3 is a partially enlarged vertical cross-sectional view of a gas discharge pipe.

The overall structure of the mold apparatus for forming hollow molded products is the same as the conventional one shown in FIG. 4, so a detailed explanation thereof will be omitted, and only the parts related to the present invention will be explained below using the same figure. do.

First, as shown in FIG. 3, the parison 2 is suspended from the die 1, and when the two molds are brought together, the gas exhaust pipe TOAB is inserted into the insertion hole 105 provided in the female mold 4. The front end of the gas exhaust pipe enters inside the parison 2 by moving it forward by driving an air syringe or the like to break the parison 2. Note that this gas exhaust pipe 103
A sealing material 106b such as an O-ring or packing is held between the pack plate 50 of the mold and the pack plate 50 of the mold to maintain airtightness in the mold cavity.
A sealing material holding fitting 104b for fixing the sealing material to 0 is disposed.

This also applies to the gas introduction pipe 103a.

Here, the mounting interval between the gas introduction pipe 103a and the gas discharge pipe 103b is set so that the gas introduction pipe 103a and the gas discharge pipe 103b
When the heating blowing air is introduced from 03a, in order to uniformly heat the entire inside of the parison 2 in a short time with the sensible heat of the heating blowing air, it is necessary to form a gas flow as much as possible throughout the inside of the parison 2. They are spaced apart. In addition, sufficient air pressure is required inside the parison 2 in order to bring the parison 2 into closer contact with both molds using the heated blowing air introduced from the gas introduction pipe 103a, and this can be ensured. A pressure control valve is provided on the outlet side of the gas exhaust pipe 103b.

Gas introduction pipe 103a and gas discharge pipe 1 in the present invention
The outer diameter of the tip of 03b is, for example, 6 mm.

Next, the operation of the molding die device of the present invention will be explained.

Now, as shown in Figure 2, before the parison 2 hangs down from the die 1, a 60° radiant instantaneous heater using near-infrared rays is used to heat the surface area of both molds to extrude and hang the parison 2. When the die 1° and the male mold 3 and female mold 4 are brought close to each other for mold clamping, heating blowing air is blown from the gas introduction pipe 103a so that the parison 2 is brought into closer contact with both molds. .

After the male mold 3 and female mold 4 are clamped, a cooling medium is heated from the mold temperature controller through the piping 51 or the cooling medium is introduced from the cooling medium inlet side through hole 41 and the ribs 33 are bored. The desired cooling is performed while passing through the provided conduction hole 34, and finally the heating or cooling medium is led out from the heating or cooling medium outlet side conduction hole 42 bored in the mold frame 40. As a result, the mold surface area 20 is cooled, and the heated blowing air blown from the gas introduction pipe 103a is switched to low-temperature blowing gas to cool the inside of the parison 2, and after a certain period of time, the parison 2 is cooled. Stop blowing the low-temperature blowing gas, open both molds, and take out the molded product.

In the present invention shown in the examples, air or oil is used as a temperature regulating medium for heating or cooling the inside of the parison 2, but in order to shorten the molding cycle of the product, the cooling medium is As the gas, liquefied gas or the like can be vaporized using a vaporizer.

Also, a mold frame 40. Since the structure is a combination of the pack plate 50 and the mold surface area 20,
By using a good thermal conductor such as A1 alloy or Cu alloy for the material of the mold surface area 20, and using a material that has been machined into a thin shape by press molding, casting, or machine cutting, the desired mold can be formed in a short time. It is also easily possible to achieve synergistic effects from both heating and cooling, such as reaching higher temperatures and shortening the molding cycle of the product.

In the present invention, the gas introduction pipe and the gas discharge pipe are arranged separately on the female mold 4, but the invention is not limited thereto, and they may be arranged separately on the male mold 3.

[Effects of the Invention] As described above, according to the present invention, since the thin gas inlet pipe and the gas discharge pipe are spaced apart from each other in the mold, clogging at the tip of the inlet pipe and large A gas flow is formed, and the sensible heat brought in by gases such as air for heating blow during heating and gas for low temperature blow during cooling can be effectively used, resulting in good transferability and good surface texture (surface roughness). It is possible to obtain a molded product (with a small diameter) and to shorten the molding cycle.

[Brief explanation of drawings]

1 to 3 show one embodiment of a mold apparatus for forming a hollow molded product according to the present invention. FIG. 1 is a perspective view of a molding die apparatus, FIG. 2 is a vertical sectional view of the molding die, and FIG. 3 is a partially enlarged vertical sectional view of a gas discharge pipe. FIG. 5 is a vertical sectional view of a conventionally known molding die, and FIG. 5 is a partially cutaway sectional view of a syringe. l...Dice, 2...Parison, 3...Male mold, 3a...Male mold surface, 4...Female mold, 4a ...Female mold surface. 20... Mold surface area, 30... Intermediate layer, 40... Mold frame, 50... Back plate, 60... -Radiation type instant heater, 100...Gas injector, 103a...Gas introduction pipe, 103b...Gas discharge pipe.

Claims (1)

[Claims] A gas introduction pipe for introducing heating or cooling gas into the inside of the parison located between a fixed mold and a movable mold during molding and a gas discharge pipe for discharging the introduced gas are attached to the mold at a distance from each other. Molding equipment for hollow molded products.