JPH0624763B2 - Device for molding hollow double structure product and method for controlling temperature of mold for hollow double structure product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold for molding a hollow double-structured article of synthetic resin and a method for controlling temperature.

[Prior Art] Here, the prior art will be described in detail with reference to a longitudinal sectional view of a conventionally known molding die shown in FIG. The molding die device in FIG. 3 comprises a die 1, a male die 3 and a female die 4.

First, in the male die 3, a temperature control medium pipe 5 for passing a cooling gas or liquid is embedded in a corner portion near the die surface 3a fitted with the female die 4, and further, Local heating coils 6 are embedded near the corners of the mold surface 3a of the male mold 3 so as to promote the expansion of the parison 2.

On the other hand, in the corner portion of the female mold 4, an air-sending porous plate 7 for sending cold air for forced cooling and a deaeration porous plate 8 for degassing the sent cold air are embedded respectively. The blower pipe 9 and the deaeration pipe 10 are connected to each other, and a local heating coil 6 is embedded in the vicinity of the mold surface 4a other than the corner area, like the male mold 4.

When a hollow double-structured article is molded with the molding die thus configured, first, the local heating coil 6 embedded in both the male die 3 and the female die 4 is energized to The mold surfaces 3a and 4a are heated to a predetermined temperature. Next, the cylindrical parison 2 is hung from the die 1, and the tip end of the parison 2 is brought into close contact with a bag with a contact jig (not shown). The male mold 3 and the female mold 4 are moved so that the parison 2 is sandwiched between the two molds, and at the same time, the air injector 100 is inserted and blown air (5 to 10 kg / cm ² ) is blown into the parison. In the process of sandwiching (molding) 2 between the molds, if air is sent from the air blow pipe 9 through the air sending porous plate 7 in order to prevent the wall thickness of the female die 4 from decreasing at the corners, cool air As a result, the deformation resistance of the corner portion of the female die 4 of the parison 2 is increased and local extension at the corner portion is prevented. Further, a degassed perforated plate (the same as the perforated plate 7) 8 for degassing is provided at a right angle to the air perforated porous plate 7 in order to degas the cool air sent from the blower pipe 9 in the corner portion. Direction, to which the deaeration pipe 10 is connected. As described above, the local heating coil 6 is provided in the vicinity of the corner of the female die 4 so as to promote the extension of the parison 2, and the die surfaces 3a and 4a of the fitting portion of the male die 3 and the female die 4 are joined together. Parison 2 because it is buried nearby
It is possible to form a molded product with little change in wall thickness without being damaged.

[Problems to be Solved by the Invention] However, in molding a hollow double-structured article using this type of molding die, the surface conductivity of the die is low,
It takes time to cool and heat the mold through a temperature control medium such as water or oil in the pipe, which lengthens the molding cycle, and the dimensional accuracy of the molded product is poor due to uneven cooling of the mold surface. There were wrinkles and wrinkles. Furthermore, the surface quality, so-called so-called gloss and transferability, was a bottleneck for blow molding.

[Means for Solving the Problems] Therefore, in the present invention, in a mold for molding a hollow double-structured article by blow molding, a porous plate for air vent is provided in both mold surface areas of a male mold and a female mold. And hot air blowing perforated plates are embedded at regular intervals to provide an air-permeable intermediate layer in the lower layer of the mold surface area and a temperature control medium retention chamber in the lower layer of the intermediate layer. Then, the molding die is provided with a hot air blowing heating device, a temperature control medium suction / discharge device, a radiant instantaneous heating device, and the like, and the temperature control of the die and the application of vacuum force are performed simultaneously by the same device.

[Operation] According to the present invention, the parison is first extruded from the die and the surface of the pipe is evenly heated by the instantaneous heater, while the mold surface members of the male mold and the female mold are made of a metal material having a high thermal conductivity. After building a porous plate for blowing hot air and for degassing between the parison surface and the mold surface, blow hot air to the parison surface, and further to the lower layer part a composite material of non-metal and resin Incorporating a breathable intermediate layer made of, etc. into the mold base, and passing the temperature adjusting medium introduced from the adjacent temperature adjusting medium retention chamber through the intermediate layer part, and the gas in the cavity and the temperature adjusting medium are introduced. By sucking with the same vacuum pump, high-speed heating and rapid suction are possible, and as a result, the molding cycle can be shortened and a molded product with excellent transferability can be manufactured.

[Embodiment] FIGS. 1 and 2 show one embodiment of a molding die for an intermediate double structure according to the present invention. FIG. 1 is a longitudinal sectional view of the molding die, and FIG. The perspective view of a metal mold | die apparatus for molding is shown.

The molding die apparatus of the present invention will be described in detail with reference to FIGS. 1 and 2.

The molding die device of the present invention comprises a die 1, a male die 3 and a female die 4.

The male mold 3 and the female mold 4 are air vent porous plates (50) for blowing hot air and sucking and discharging the air in the cavity.
8a, a mold surface member 20 arranged at regular intervals on the mold surface, and a non-metal or resin composite material having air permeability in the middle region of the mold. The filled intermediate layer 30 and the parison 2 are blow-molded in a molding die and then a cooling medium is introduced into the die for solidifying after solidifying, so that the entire die is uniformly cooled.
It consists of Further, the intermediate layer 30 is connected to the warm air blowing porous plate (having a large number of holes of 50 to 200 μm) 8b arranged at regular intervals on the mold surfaces 3a and 4a. A wind introduction pipe 50 is provided and communicates with the respective sections of the mold surface area 20, the intermediate layer 30 and the temperature control medium retention chamber 40 through pores. As the radiant instant heater, for example, a near infrared halogen lamp (a rod-shaped object is attached to a heater container) manufactured by Philips is processed to heat the surface of the parison 2 instantly and evenly. I was there.

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

Now, the parison 2 is hung down from the extruder (not shown) through the die 1, and the tip end of the parison 2 is brought into close contact with a bag by a contact jig (not shown), and the instantaneous heater 200
(Illustrated in FIG. 2) is inserted and the surface of the parison 2 is heated to a predetermined temperature. After heating for a certain period of time, the instantaneous heater 200
Back to the original position. Next, the male die 3 and the female die 4 are moved so that they are close to each other, and the parison 2 is sandwiched between the male die 3 and the female die 4 and, at the same time, the air injector 1
00 is blown in and blown air is blown to bring the parison 2 into closer contact with the mold. The male mold 3 and the female mold 4
Prior to the closing of, the warm air is introduced from the warm air introduction pipe 50 and blown against the surface of the parison 2 for a certain period of time by the hot air blowing porous plate 8b so that the surface of the parison 2 is uniformly heated again to facilitate molding. . Immediately before the closing of the male mold 3 and the female mold 4, the feeding of warm air is stopped. On the other hand, by driving a vacuum unit (not shown) at about the same time as the warm air blowing before closing, the air in the cavity is sucked and vacuumed from the air vent perforated plate 8a, thereby causing the parison 2 to move to the male mold 3. The cavity surfaces 3a and 4a of both dies of the female die 4 can be naturally brought into close contact with each other. After that, after the molds are closed, the blow air operation from the air injector 100 is also stopped at appropriate times. Then, the temperature control medium source of the cooling gas or liquid is fed into the temperature control medium retention chamber 40 from the inlet, and further to the intermediate layer 30 of the adjacent chamber loaded with the air-permeable non-metallic or resin composite material. Is introduced through the pores provided in the shielding wall, and at the same time, the temperature control medium for cooling is sucked by the vacuum unit.

Although water is used as the temperature control medium in the present invention, liquefied carbon dioxide gas or the like vaporized by a vaporizer may be used for the purpose of shortening the molding cycle.

[Effects of the Invention] As described above, according to the present invention, forced cooling and heating of the parison can be performed very easily, so that the corner portion of a shallow (shallow depth) molded product is molded. Of course, the moldability of deep (deep depth) molded products is improved, and molded products with less variation in wall thickness can be easily obtained. In addition, the above-mentioned instantaneous heating and rapid suction can be performed. The molding cycle can be shortened, and a molded product with more excellent transferability can be obtained.

[Brief description of drawings]

1 and 2 show one embodiment of a molding die for a hollow double structure product according to the present invention. FIG. 1 is a longitudinal sectional view of the molding die, and FIG. 2 is a molding die. FIG. 3 is a vertical sectional view of a conventionally known molding die, which is a perspective view of the apparatus. 1 ... Die, 2 ... Parison, 3 ... Male mold, 3a ... Male mold cavity surface, 4 ... Female mold, 4a ... Female mold cavity surface, 5 ... Temperature control medium Pipe, 6 ... Local heating coil, 7 ... Air perforated plate, 8 ... Degassed perforated plate, 8a ... Air vent perforated plate, 8b ... Warm air blowing perforated plate, 9 ... Air blow pipe 10 ... Deaeration pipe, 20 ... Mold surface area, 30 ... Intermediate layer, 40 ... Temperature control medium retention chamber, 50 ... Warm air introduction pipe, 100 ... Air injector, 200 ... Instant Heater.

Claims (3)

[Claims] 1. A mold for molding a hollow double-structured product by blow molding, wherein a perforated plate for air vent and a perforated plate for blowing warm air are arranged at a constant interval in the surface area of both molds of a male mold and a female mold. Of a hollow double-structured article, characterized in that the intermediate layer having air permeability is provided in the lower layer portion of the mold surface area and the temperature control medium retention chamber is provided in the lower layer portion of the intermediate layer. Molding equipment for molding. 2. A mold apparatus for molding an intermediate double structure, wherein the apparatus according to claim 1 is provided with a radiation type instantaneous heating apparatus. 3. A mold for molding a hollow double-structured article in a mold apparatus according to claim 1, wherein a vacuum force is applied by degassing of the cavity and the temperature of the mold is adjusted at the same time during molding. Temperature control method.