JP2000280290A - Method and apparatus for preventing bedewing of cooling part of injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the bedewing of the surface of a cold nozzle for injecting a molding material by blowing or circulating air opposite to the periphery of the cold nozzle. SOLUTION: Since the injection nozzle 48 of an injection molding machine for injecting a molding material opposite or connected to a mold heated at a high temperature is exposed always to a high temperature so that the molding material in the nozzle 48 is solidified by heat, or since the injection nozzle (cold nozzle = CN) 48 having a cooling part is rusted by the bedewing of moisture in air, rust prevention is necessary together with the cooling of the injection nozzle 48. The dehumidification by air is done by air nozzles 1 of places which can eject air 5 from diagonally above opposite to CN 48, the air nozzles 1 blow air over the entire length of CN 48, or are made to be able to circulate air. The blown air or the circulated air prevents bedewing and blows heat from a mold positioned below to prevent the conduction of heat, and the bedewing is prevented more effectively by using dry air. In this way, bedewing on the periphery of CN 48 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection molding machine for molding a resin, and more particularly to an injection nozzle of an injection molding machine for molding a thermosetting resin such as liquid silicone rubber.

[0002]

2. Description of the Related Art An injection nozzle of an injection molding machine is a final section for guiding a raw material resin into a mold cavity. In particular, in order to obtain a high quality molded product using a thermosetting resin such as liquid silicone rubber. Is an important part that must be prevented from curing the molding compound in the flow path before injection. In order to prevent the molding material from hardening in the flow path before the injection, a cooling means is provided near the molding material flow path of the injection nozzle to cool the heat transmitted from the mold. Means have been taken conventionally.

[0003] Such an injection nozzle having a cooling means is generally called a cold nozzle. Some of the cold nozzles are used in, for example, a screw-in-line type injection molding machine as shown in FIG. In this injection molding machine, the liquid A and the liquid B which are kept cool at 25 ° C. or less are supplied into the cylinders 43 of the supply pipes 41 and 42, respectively, and the molding material supplied into the cylinder 43 is supplied to the injection molding machine. While being kneaded by the screw 44 which is rotated by the drive of the motor 46, it is fed into the resin reservoir 50 at the tip. The pressure of the resin fed into the resin reservoir 50 gradually increases due to the continuous rotation of the screw 44, and when the resin reaches a predetermined pressure, the screw 44 is retreated by the reaction force. When the screw 44 is retracted to a predetermined position, the limit switch 47 is operated, the rotation of the motor 46 is stopped, and at the same time, the cylinder 49 is operated. 51. At the same time, the flow path of the nozzle 48 is opened by opening / closing means (not shown), and the molding material in the resin reservoir 50 is pressed by the advance of the screw 44 by the operation of the cylinder 51, and is injected into the mold 51. Configuration.

In such a configuration, the mold 51 is
Since the nozzle 48 and the cylinder 43 facing the mold 51 are heated to a high temperature of 30 to 200 ° C.
It is easy to be heated by the heat of 1
There is a problem that the molding material in 43 hardens and injection becomes difficult. In order to solve this problem, a cooling water flow path (not shown) is conventionally formed inside the cylinder 43, or as shown in FIG.
5 are provided. In this case, there is a problem that the outer periphery of the cooling jacket is dewed and water droplets are dropped and rust is generated around the molding machine and the mold. For this reason, a heat insulating material is wound around the outer periphery of the cooling jacket to prevent heat conduction and to adjust the humidity in the room to prevent dew condensation. The heat insulating material has a problem that it is not only difficult to wind up to the tip of the nozzle, but also that the portion close to the mold is easily deteriorated by heat. For this reason, a heat insulating material is not often used at the nozzle tip, so that dew condensation cannot be completely prevented.

[0005]

However, when the conventional cold nozzle for molding a thermosetting resin is cooled, humidity in the air condenses around the nozzle. This condensation occurs even when a heat insulating material is wound around the nozzle. And there was a problem that this dew made the molding machine rust, and when it fell as water droplets, the mold also rusted. In addition, when the heat insulating material is wound, the outer circumference becomes large, and especially, the sliding portion interferes. Further, in some places where the molding machine is complicated, the heat insulating material cannot be wound. There is also a method to prevent dew condensation by adjusting the temperature and humidity of the room where the molding machine is installed, but it is rarely used in production plants because it is too many rooms to adjust and costs are high. It is the current situation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an apparatus and a method for preventing dew condensation in a cooling section of an injection molding machine, which prevent dew condensation on the surface of a cold nozzle for injection of a molding material. And

[0007]

In order to achieve the above object, an invention according to a first aspect of the present invention is directed to an apparatus for preventing condensation in a cooling section of a thermosetting resin molding injection molding machine, comprising an injection nozzle having a cooling means (hereinafter referred to as a cold nozzle). And a circulating means for circulating the air. Claim 1
According to this, by providing the air injection means and injecting or circulating air around the outer periphery of the cold nozzle, it is possible to prevent dew condensation on the outer periphery of the cold nozzle. This solves the problem that the nozzle and the mold die rust.
Further, since the air injection means or the air circulation means is a simple device, even if the air injection means or the air circulation means is mounted on the cold nozzle, it does not interfere with peripheral devices. Even when a heat insulating material is wound around the cold nozzle, the effect of preventing dew condensation can be obtained by injecting air or injecting air from outside.

[0008] The invention of claim 2 is characterized in that the air injection means and the air circulation means comprise an air nozzle for injecting air from a plurality of directions facing the cold nozzle or a nozzle for circulating air. According to the second aspect, it is possible to prevent dew condensation by injecting or circulating air from a plurality of directions around the cold nozzle. Even if some dew condensation occurs, water drops can be immediately removed by being blown off by the movement of air.

According to a third aspect of the present invention, the air injection means and the air circulation means wrap a cold nozzle around a jacket and inject or circulate air from one of the jackets into the inside thereof. An air nozzle and a discharge port, a suction air nozzle and a supply port which are discharged or supplied from the other side are provided. According to the third aspect, a configuration is adopted in which the periphery of the cold nozzle is wrapped in a jacket as the air injection means and the air circulation means, and air is injected or circulated from one side and discharged or supplied from the other inside the jacket. Thus, the injection air or the circulating air can be effectively passed around the entire periphery of the nozzle.
In this case, the effect of preventing dew condensation can be further enhanced. This eliminates the need to wind a heat insulator around the nozzle.

According to a fourth aspect of the present invention, the blast air or the circulating air comprises dry air. According to the fourth aspect, since the dry air does not include moisture, it is possible to prevent dew condensation more efficiently than in the humid atmosphere.

According to a fifth aspect of the present invention, there is provided an apparatus for preventing dew condensation in a cooling section of an injection molding machine for molding a thermosetting resin, wherein air is injected or circulated from an air injection means and an air circulation means so as to face an outer periphery of a cold nozzle. It is characterized by the following. According to the fifth aspect, it is possible to prevent dew condensation around the cold nozzle by air injected from the air injection unit or air circulated by the air circulation unit.

The invention according to claim 6 is characterized in that air is injected from a plurality of directions around the cold nozzle by using an air injection means comprising a plurality of air nozzles or circulation nozzles and an air circulation means. According to the sixth aspect, by injecting or circulating air from a plurality of directions with the air nozzle, it is possible to prevent condensation on the surface of the cold nozzle.

According to a seventh aspect of the present invention, there is provided an air-injecting means and a circulating means in which the periphery of the cold nozzle is wrapped by a jacket, and air is injected from one side of the jacket and discharged or supplied from the other side. And injecting or circulating air around the cold nozzle. According to the seventh aspect, an air injection unit or an air circulation unit configured to wrap the periphery of the cold nozzle with a jacket, inject or circulate air from one side to the inside, and discharge or supply from the other side is used. By
Injection air or circulating air can be effectively passed around the entire periphery of the nozzle, and the effect of preventing dew condensation can be further enhanced as compared with the case of the sixth aspect. This eliminates the need to wind a heat insulator around the nozzle.

The invention according to claim 8 is characterized in that dry air is injected or circulated around the cold nozzle. According to the eighth aspect, the same effect as the seventh aspect can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In addition, common points in the above-described conventional technology and each embodiment are assigned the same reference numerals and correspond to each other to omit redundant description.

(Embodiment 1) FIG. 1 is a sectional view showing an apparatus for preventing dew condensation in a cooling section of an injection molding machine according to Embodiment 1 of the present invention.

The injection molding machine applied to the present invention injects a liquid silicone rubber, which is a thermosetting resin, as a molding material into a mold heated to about 130 to 200 ° C. The molding material is rapidly heated by the heat of the mold, and is cured by a crosslinking reaction to form a molded product.

Since the injection nozzle of the injection molding machine which faces the mold heated to a high temperature and which is connected to and injects the molding material is always exposed to the high temperature, the heat of the mold is easily conducted. Since the molding material in the injection nozzle is solidified by the heat, the injection nozzle needs to be cooled. As the cooling method, for example, a cooling means 45 for cooling from the outside as shown in FIG. 1 or a cooling means in which a flow path of the refrigerant is formed in the thickness is provided.

However, dew condensation on the surface of the nozzle cooled in this way due to moisture in the air causes the cold nozzle to rust, and if it falls on the mold surface as water droplets, rusts the mold. It turns out that.

Incidentally, this dew condensation will be described.
First of all, it is very important how much water vapor is in the room. As shown in Table 1, when the indoor water vapor pressure is, for example, 12 mmHg (weight absolute humidity is 9.97 g / kg), the relative humidity is 68% at a room temperature of 20 ° C. and 94% at a room temperature of 15 ° C. % Or less, it becomes a saturated state, and when the temperature becomes 15 ° C. or less, it becomes a state in which dew condensation easily occurs.
In addition, 8mmHg vapor pressure (weight absolute humidity is 6.61g / kg)
If so, the relative humidity becomes 46% at 20 ° C., and does not saturate unless it reaches 8 ° C. Therefore, it is necessary to reduce the amount of water vapor in the room to reduce the condensation.

[0021]

[Table 1] In order to prevent this dew condensation, in the present embodiment, an air injection means or an air circulation means is provided to face the cold nozzle surface. The air is injected or circulated from the air injection means or the air circulation means to the cold nozzle surface.

This air injection means or air circulation means
The air nozzle 1 is capable of injecting the air 5 from two to four obliquely upwards facing the cold nozzle. The air nozzle 1 is provided with air 5 from obliquely above the cold nozzle.
Or the air 5 is circulated, so that it is possible to blow or circulate air over the entire length of the cold nozzle, and the blown air or circulating air prevents condensation and forms a mold located below. It is also useful to blow off heat from the body to prevent heat conduction. Also,
By using the dry air 5 as the blast air or the circulating air, it is possible to more effectively prevent dew condensation.

Further, since the air injection means or the air circulation means having this structure has a simple structure, even if it moves up and down together with the cold nozzle in a state where it is fixed to the cold nozzle, no trouble occurs in peripheral equipment.

When a heat insulating material is wound around the outer periphery of the cold nozzle, it is possible to prevent dew condensation by injecting air or circulating air from outside the heat insulating material. The position of the air nozzle 1 is not limited to a plurality of positions obliquely above the cold nozzle.
May be injected or circulated.

According to the present embodiment, since it is the simplest configuration including an air nozzle, it is possible to install equipment at low cost.

(Embodiment 2) FIG. 2 is a sectional view showing an apparatus for preventing dew condensation in a cooling section of an injection molding machine according to Embodiment 2 of the present invention.

In this embodiment, instead of the air nozzle 1 in the first embodiment, the periphery of the cylinder 43 of the cold nozzle is wrapped in a jacket 2, and air 5 is introduced into the inside of the jacket 2 from one side. The air 5 is ejected or circulated, and the air 5 is discharged or supplied from the other side. The other configuration is the same as that of the first embodiment, and the description is omitted.

The jacket 2 wraps around the outside of the cylinder 43 of the cold nozzle, forms an air flow path between the jacket and the cylinder 43, and injects or circulates air into the air flow path. Is provided at one end in the longitudinal direction of the jacket 2 and an air discharge port 4 is provided at the other end, and after ejected or circulated air passes through the entire outer periphery of the cold nozzle, air is discharged or air is supplied. It is configured as follows.

By injecting or circulating the dry air 5 into the jacket 2 having this configuration, it is possible to reliably prevent dew condensation.

According to the present embodiment, the air 5 injected or circulated from one side of the jacket 2 through the outer peripheral surface of the cylinder 43 of the cold nozzle is discharged or supplied from the other side. Thus, the effect of preventing dew condensation can be further enhanced as compared with the case of the first aspect.

In the first and second aspects, dry air is used as the blast air 5 or the circulating air 5. However, the present invention is not limited to this. It is possible to

[0032]

According to the present invention, it is possible to prevent dew condensation on the outer periphery of the cold nozzle by injecting or circulating the air around the outer periphery of the cold nozzle by the air injection means or the air circulating means. .

By injecting or circulating dry air in a jacket surrounding the outer periphery of the nozzle, dew condensation can be more effectively prevented.

Further, since the air injection means or the circulation means is a simple device, even if the nozzle is operated with this device mounted, there is no interference with peripheral devices and the cost is low. Equipment.
There is no need to wind a heat insulator around the nozzle. This solves the problem that the nozzle and the mold die rust.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a dew condensation preventing device of a cooling unit of an injection molding machine according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a dew condensation preventing device of a cooling unit of an injection molding machine according to Embodiment 2 of the present invention.

FIG. 3 is a sectional view showing a conventional injection molding machine.

[Explanation of symbols]

 1, 3 Air nozzle 2 Jacket 4 Outlet 5 Injected air 43 Cylinder 44 Screw 45 Cooling means 48 Nozzle

Claims (8)

[Claims] An apparatus for preventing dew condensation at a cooling section in an injection molding machine for molding a thermosetting resin, comprising: an air injection means for blowing air in opposition to an outer periphery of an injection nozzle having a cooling means (hereinafter referred to as a cold nozzle); A dew condensation preventing device for a cooling unit of an injection molding machine, comprising: a circulating unit for circulating water. 2. The injection molding method according to claim 1, wherein said air injection means and said air circulation means comprise an air nozzle which injects air from a plurality of directions facing a cold nozzle or a nozzle which circulates air. Condensation prevention device for cooling unit. 3. The air injection means and the air circulation means wrap a cold nozzle around a jacket and inject air into one of the jackets or circulate the air and discharge the air from the other. 2. The apparatus according to claim 1, further comprising a supply air nozzle and a discharge port, a suction air nozzle and a supply port. 4. The apparatus according to claim 1, wherein said blast air and said circulating air are made of dry air. 5. A method for preventing dew condensation in a cooling section in an injection molding machine for molding a thermosetting resin, comprising: injecting or circulating air from an air injection means and said air circulation means in opposition to an outer periphery of a cold nozzle; A method for preventing dew condensation in a cooling section of an injection molding machine, wherein dew condensation is prevented on an outer periphery. 6. A cooling unit for an injection molding machine according to claim 5, wherein air is injected from a plurality of directions around the cold nozzle by using an air injection means comprising a plurality of air nozzles or circulation nozzles and an air circulation means. How to prevent condensation. 7. A cold nozzle is wrapped around the cold nozzle by using an air injection means and a circulating means configured to wrap air around the cold nozzle from one side of the jacket and discharge or supply air from the other side. 6. A method for preventing dew condensation in a cooling section of an injection molding machine according to claim 5, wherein air is injected or circulated through the cooling device. 8. The method for preventing dew condensation in a cooling section of an injection molding machine according to claim 5, wherein dry air is injected or circulated around the cold nozzle.