JP3063210B2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die, and more particularly to a lightweight injection molding die suitable for reaction injection molding, in which the temperature of the die is easily controlled.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional injection mold used for general injection molding includes a fixed mold 4 attached to a fixed board 2 and a movable mold set to a movable board 6. And a mold 8. The movable platen 6 is moved toward and away from the fixed platen 2 along the tie bar 12 by driving means such as a pressure cylinder 10. When the movable platen 6 approaches the fixed platen 2 and the split surface of the fixed die 4 and the split surface of the movable die 8 are joined, a cavity is formed inside. A resin for injection molding is injected into the cavity, and the two dies 4 and 8 are tightened at a predetermined pressure, whereby the resin is injection-molded in the cavity.

In such injection molding dies used for general injection molding, since the pressure inside the dies is high and a uniform pressure is required, the fixed dies 4 and the movable dies 8 are required. And the molds 4 and 8 need to be directly attached to the fixed platen 2 and the movable platen 6 without any gaps.

[0004]

Such a conventional injection molding die involves a reaction such as reaction injection molding of a urethane resin, reaction injection molding of a nylon resin, or reaction injection molding of a norbornene resin. When applying to injection molding, polymerization activity is greatly affected by the temperature of the mold, so in order to stably produce desired products,
It is necessary to control the mold temperature with high accuracy. Generally, this temperature control is performed by a heat exchange means such as a copper tube coil or a jacket provided in a mold.

However, in the conventional injection molding dies, the dies 4 and 8 are directly mounted on the fixed platen 2 and the moving platen 6, respectively. Heat transfer to the mold 6 cannot be neglected, and it is difficult to control the temperature inside the mold.
As means for solving such inconvenience, it is conceivable to interpose a heat insulating material on the mounting surface between the dies 4, 8 and the fixed platen 2 or the moving platen 6. However, the mold 4,
8 and the fixed platen 2 or the moving platen 6 need to be accurately performed for reasons such as matching the split surfaces of the dies. However, when a heat insulating material is used, the heat insulating material generally has dimensional stability. And the mechanical strength is weak, so that it is difficult to accurately attach the dies 4 and 8 to the fixed platen 2 or the moving platen 6.

In recent years, relatively large injection molded products have been desired in the market. However, when large injection molding is performed using a conventional injection molding die, the weight of the die is reduced. Becomes too heavy, handling becomes inconvenient, and the ability of the driving means for tightening the mold becomes large, so that it cannot be produced economically.

[0007] The present invention has been made in view of such circumstances, and is easy to control the temperature of the mold, lightweight and easy to handle, convenient for storage and transportation, and particularly suitable for injection molding. The purpose is to provide a type.

[0008]

In order to achieve the above object, an injection molding die according to the present invention comprises a stationary die attached to a stationary plate, and a movable die attached to a movable plate. Having a cavity into which resin is injected by moving the moving plate closer to the fixed plate and joining the split surface of the fixed die and the split surface of the movable die. Wherein the fixed mold and the movable mold are mounted on the surface of the fixed plate and the surface of the movable plate, respectively, so that an air layer sufficient for heat insulation is formed. It is characterized by.

[0009]

In the injection mold according to the present invention, an air layer is formed between the mold and the fixed platen or the moving platen.
This air layer plays the role of a heat insulating layer, which facilitates temperature control of the mold. Further, in the reaction injection molding, since the pressure in the mold does not need to be so increased, the thickness of the mold can be reduced by an amount corresponding to the formation of the air layer, so that the weight of the mold can be reduced.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a mold for injection molding according to the present invention. FIG. 1 is a side view of an injection mold according to one embodiment of the present invention, and FIG. 2 is a side view of an injection mold according to another embodiment of the present invention.

An injection mold 20 according to an embodiment of the present invention shown in FIG. 1 is used for, for example, reaction injection molding, and has a relatively thin moving mold 22 and a fixed mold 24. ing. These dies 22 and 24 are separated from each other by split surfaces 22 a and 24.
a, the cavity 26 into which the resin is injected is formed. An injection port for injecting the resin into the cavity 26 is omitted in the drawing. The cavity 26
Is usually formed inside the fixed mold 24 as shown in the figure, but may be formed inside the movable mold 22. Although not shown, these molds 2
Heat exchange means, such as a copper tube coil and a jacket, are attached to 2, 24.

In order to form air layers 28, 28 sufficient for heat insulation between the fixed platen 2 or the moving platen 6 on the surface opposite to the split surface of each of the dies 22, 24, they are used as mounting members. One end 30a of the H-shaped steel member 30 is previously attached at a predetermined interval by connecting means such as a bolt 32. Each H-shaped steel 3
At 0, a suspension hole 34 for transporting the mold is formed,
That portion may be reinforced with a reinforcing plate or the like. Further, in order to reinforce the entire H-shaped steel material 30 as a mounting member, predetermined H-shaped steel materials 30 may be connected to each other by a reinforcing rod 36. Such an H-shaped steel material 30 is
Pre-installed on each mold 22, 24,
The respective dies 22 and 24 are fixed to the fixed platen 2 or the moving platen 6
For example, a bolt is passed through a bolt hole formed in the other end 30b of the H-shaped steel member 30 and screwed.

The positional relationship between the movable platen 6 and the fixed platen 2 may be horizontal, as shown in FIG. 3, for example.
Alternatively, they may be arranged vertically. The driving means for moving the movable platen 6 closer to the fixed platen 2 and performing mold clamping is not particularly limited, and examples thereof include a pressure cylinder and an electric motor.

H-shaped steel material 30 provided on fixed side mold 24
Height h 1 means that an air layer 28 sufficient for heat insulation is formed
Although not particularly limited, the cavity 26
In front of the mixing section of an injection molding machine for injecting resin into
For arrangement in the space 28, preferably 300
mm or more, more preferably 400 to 600 mm. one
On the other hand, the height of the H-shaped steel material 30
H 2 so that an air layer 28 sufficient for heat insulation is formed
It is determined, and there is no particular limitation.
In the direction away from the
From the viewpoint of facilitating the removal operation, 100 to 300 mm
Is preferred. Furthermore, the width w of these H-shaped steel materials 30 is particularly
Not limited, but determined by the size of the molds 22, 24
Generally, it is 200 mm to 300 mm. Also, H
The thickness of the mold steel material 30 is determined by the weight of the dies 22, 24.
Is determined.

In the injection molding die 20 according to the present embodiment, an air layer 28 is formed between the dies 22, 24 and the fixed platen 2 or the moving platen 6, so that the air layer 28 is formed.
Plays a role of a heat insulating layer, and temperature control of the mold 20 becomes easy. According to the experiment, the speed of raising the temperature of the mold at the start of injection molding is about twice that of the conventional technique, and the mold temperature during continuous injection molding is kept uniform. Further, in the reaction injection molding, since the pressure in the mold 20 does not need to be increased so much, the molds 22 and 2 are formed only by the formation of the air layer 28.
Since the thickness of 4 can be reduced, the weight of the mold can be reduced. For example, when performing reaction injection molding of a norbornene-based resin, the pressure in the mold may be set to about 1 to 3 kg / cm ^2. %, And in some cases, as much as 50%.
Further, since the H-shaped steel material 30 as a mounting member has a sufficient mechanical strength, the dies 22, 24 can be mounted on the fixed platen 2 or the moving platen 6 with high accuracy. Furthermore, if the shape and the mounting interval of the H-shaped steel material 30 for providing the air layer 28 are fixed regardless of the size of the dies 22, 24, the mounting and replacement work of the dies 22, 24 is extremely easy. , And the mounting time can be reduced. Furthermore, since the H-shaped steel material 30 for forming the air layer 28 is previously attached to both the dies 22 and 24, the H-shaped steel material 30 is used to facilitate transportation, and the dies 22 and 24 are used. Since the H-shaped steel material 30 is provided outside the mold 24, the molds 22 and 24 can be prevented from being damaged, which is convenient for storage.

The present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the present invention. For example, the mounting member is not limited to the H-shaped steel material 30, but may be a grooved steel material 30a having a U-shaped cross section, an angled steel material having an L-shaped cross section, or another shape as shown in FIG. Further, such a mounting member may be formed integrally with the respective molds 22 and 24. In any case, it is preferable that such an attachment member is attached to the molds 22 and 24 in advance for the convenience of transportation and storage. However, in some cases, the attachment member is attached to the fixed platen 2 or the movable platen 6 in advance. You may do it.

[0017]

As described above, according to the injection molding die of the present invention, an air layer is formed between the die and the fixed platen or the moving platen. It plays the role of a heat insulating layer and facilitates temperature control of the mold. Further, in the reaction injection molding, since the pressure in the mold does not need to be so increased, the thickness of the mold can be reduced by an amount corresponding to the formation of the air layer, so that the weight of the mold can be reduced. Therefore, large-sized reaction injection molding is also possible. In addition, since the weight of the mold can be reduced, the manufacturing cost of the mold can be reduced, and at the same time, the ability of the driving means for driving the mold does not need to be increased. Cost can be reduced. Furthermore, if the shape and the mounting interval of the mounting member for providing the air layer are kept constant regardless of the size of the mold, the mounting and replacement work of the mold becomes remarkably easy, and the mounting time is shortened. It becomes possible to plan. Furthermore, if the attachment member for forming the air layer is formed integrally with the mold or is always attached to the mold, transportation is facilitated using the attachment member, and the attachment member is provided outside the mold. As a result, the mold itself can be prevented from being damaged, and storage is convenient.

[Brief description of the drawings]

FIG. 1 is a side view of an injection mold according to one embodiment of the present invention.

FIG. 2 is a side view of an injection mold according to another embodiment of the present invention.

FIG. 3 is a side view of a mold and a mold clamping device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 2 Fixed plate 6 Moving plate 20 Injection molding die 22 Moving die 24 Fixed die 28 Air layer 30 H-shaped steel material (mounting member) 30a Angle steel material (mounting member)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-200916 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (2)

(57) [Claims] 1. A fixed-side mold attached to a fixed board,
Having a movable mold attached to the movable board, the movable board approaching the fixed board, and the split face of the fixed mold and the split face of the movable mold are joined, so that What is claimed is: 1. A reaction injection molding mold having a cavity into which a resin is injected, wherein the fixed mold is provided on a surface of the fixed plate with a diameter of 400 to 60.
Enough air layer is formed for thermal insulation with width of 0mm
The moving side mold is attached to the surface of the moving platen by 100 to 30
Enough air layer is formed for thermal insulation with width of 0mm
A reaction injection molding die, wherein the die is attached with a steel material. 2. A method for injecting a resin into the cavity.
Of the fixed side mold and the fixed platen
2. The air conditioner according to claim 1, wherein the air layer is disposed inside the gas layer.
The mold for reaction injection molding according to 1.