JPS62109613A - Mist quenching process for mold - Google Patents

Abstract

PURPOSE:To save the usage of cooling water by spraying the mist to the inner and outer faces of heating mold of foam molding to cool it down. CONSTITUTION:The upper mold mounting frame 5 is fixed to the lower mold mounting frame rotatably with the hinge joint HJ, while the upper mold 6 is fixed to the upper mold mounting frame 5, and the upper mold is opened and closed by opening and closing the rollers 8 of upper mold along with the opening and closing guide 9. The injection liquid is injected (a) into the mold placed on the truck for travelling, and the upper mold is fit into the lower mold with the opening and closing guide 9. After passing through the heating process of oven (b) to complete the expansion cure, the upper mold is opened automatically along with the opening and closing guide 9 at the demolding process section (c) by the roller 8 of upper mold 6, the molded product being taken out, and the molds, with the upper mold open, pass through continuously the cooling process section (d) equipped with the quenching device, during which the molds are cooled down rapidly by the mist sprayed out of the nozzle.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the cooling of foam molds for rubber-based, plastic-based, etc. foams, especially urethane foam. This method is an improvement over the molding gate type mist rapid method that achieves the above effects and rapidly cools the mold without wetting the inner surface of the mold.

(Conventional technology) The conventional cooling methods for hot foaming molds, which are mainly used for molding urethane foam cushion products, can be broadly classified as follows: ■ Injecting water onto the inner and outer surfaces of the mold. How to cool it down.

■ Method of submerging the entire surface of Kinsakaki into an aquarium (Unexamined Japanese Patent Publication No. 60-24
No. 908).

d. A method in which the flange surface of the lower mold is immersed in a water tank to prevent water from entering the mold (Japanese Patent Laid-Open No. 55-30959).

■ A method in which a cover is placed around the mold mounting frame to prevent water from entering the mold, and water is poured out in a rod shape within this frame to cool the entire surface of the mold.

As mentioned above, the conventional cooling methods are included in the four systems (1) to (2).

These conventional examples have some drawbacks.

Disadvantages of method (2) above: ω When molding urethane foam with water droplets remaining on the inner surface of the mold, remaining water will disrupt the balance of the urethane reaction, causing unevenness and roughening the surface. 0 A large amount of water is used, and the water quality is contaminated, so wastewater treatment is required.

Disadvantages of method (2); ω A large-capacity water tank is required; O The water temperature rises, so it is necessary to cool it with a refrigerator, etc. (c) Water enters the mold.

Disadvantages of method ①; ω A large amount of water is used, and the water quality is contaminated, so wastewater treatment is required, and temperature control of the O-top mold is difficult.

Disadvantages of method ①; ω A large amount of water is used, the water becomes dirty and wastewater treatment is required; (f) The temperature of the upper mold cannot be controlled.

As mentioned above, conventional methods not only have extremely poor thermal efficiency for cooling, but also require a large amount of water consumption and wastewater management, in addition to requiring a large amount of man-hours to wipe off residual water inside the mold. It is.

[Problem that the invention seeks to solve]

In the conventional cooling method described above, for example, in the case of a urethane foam cushion product, if the mold temperature before injection of the polyurethane foam compound stock solution is 35° ± 5°C under the conditions of heating and molding at 100°C, the minimum amount used is For example, 100'
Approximately 30 tons/hour of cooling water was sprayed to lower the temperature from 35°C to 35°C.

The mold temperature in this case was within a controlled range of 38°±8°C, and water remained in the mold, necessitating a wiping operation. In addition, there were large variations in temperature, making it difficult to control the mold temperature during injection. If an attempt was made to prevent water from entering the mold, it would result in a partial spray, resulting in a lower cooling effect.

Therefore, in order to eliminate the drawbacks of the conventional example mentioned above, the inventor explored measures such as improving the thermally inefficient cooling method, reducing water consumption, and preventing moisture from entering the mold. It is something.

[Means for solving problems]

As a measure to solve the above problems, the inventor has taken the following measures:
They discovered a concept for rapidly cooling a heated mold by utilizing the latent heat of vaporization of water and releasing approximately 540 times the amount of heat per sensible heat.

In other words, it is a method that can rapidly cool down the heating mold by spraying an ultra-fine mist in the form of dry fog (DRY FOG) onto the heating mold, and can solve all of the drawbacks of the conventional technology at once. Because it is an ultra-fine mist that can effectively utilize the heat of vaporization of water, it can evaporate quickly, and the minimum amount of mist can be achieved without intruding moisture into the mold or creating a wet state on the inside of the mold. It exhibits the characteristic of rapid cooling depending on the amount of water.

This dry fog is formed by using a two-fluid nozzle with water and air controlled at a water pressure in the range of 0.5 to 1.0 kmCm2 and an air pressure in the range of 4 to 9 kmCm2. The average particle diameter of the sprayed particles is 10μ.
As described below, spraying onto a heated mold is a cooling method.

However, from the point of view of reducing the amount of air used in practice, the water pressure is 0.5 ka/cm2, and the air pressure is 4 to 4.5 kMc.
m2 is preferred. That is, water pressure (kMclI12)
and air pressure (k(It/Cm2)) are supplied to a two-fluid nozzle at a ratio of 1:8 to 9 to create ultra-fine fog (dry fog).
This is a mist (HIST) quenching method in which a mist is formed and sprayed onto a heating mold to rapidly cool the mold.

Then it becomes an air spray. Further, at a ratio of 1:0, the average particle diameter becomes a little large, and at a ratio of 1:6, a wetting phenomenon appears on the inner surface of the mold when sprayed onto the inner surface of the mold. Therefore, in order to achieve the purpose of ultra-fine mist, a ratio of 1:8 to 90 is the most preferable condition.

However, depending on the shape of the mold, if there is no risk that the cooling mist on the outside of the mold will cause wetting on the inside of the mold, only the outside of the mold may be used, even if the entire mold is not completely dry. can be rapidly cooled by spraying a mist with an average particle size of about 30 to 50 microns per q at relatively low air pressure.The formation of this mist can be achieved at a water pressure of 1.0 to 1.5 kg/Cll12 and an air pressure of 3.0k
M cm2, that is, the ratio of water pressure and air pressure is 1 = 3 to 2
q) is supplied to the two-fluid nozzle at a rate of . Other details will be specifically explained in Examples.

[Effect]

In the method of this invention, since the heat of vaporization of water is used effectively, the maximum heat generation effect can be obtained with the minimum amount of water, making it possible to save a large amount of water usage and providing a rapid cooling effect. It will be done. Furthermore, since the cooling water evaporates rapidly, no water wetting phenomenon occurs inside the mold.

(Example) Fig. 1 shows an example of a polyurethane foam molding die having an automatic lid opening/closing mechanism, and is an explanatory schematic front view showing a partial cross section. FIG. 2 is a schematic front view showing a state in which the lower mold and the upper mold are connected by a hinge joint HJ so as to be freely openable and closable. The foam product molded by this mold is a long cushion product having the width of the cross-sectional shape shown.

In the figure, 1 is a frame for attaching the lower die, 2 is a wheel, and 3 is a chain wheel.The frame 1 for attaching the lower die is configured to move by a chain, and the lower die 4 is attached to the frame 1. is fixed to the top frame. 5 is a frame for attaching the upper die, and is rotatably fixed to the frame by a hinge joint HJ for attaching the lower die; the upper die 6 is fixed to the frame 5 for attaching the upper die; To attach the upper mold, a clamp 7 rotatably fixed to the frame 5 by a hinge joint HJ is inserted into a fitting pin FP fixed to the lower mold 4, and is fitted and fixed to the lower mold 4. Also,
When opening and closing the upper mold, the rollers 8 of the upper mold are automatically opened and closed along a mold opening/closing guide 9 (not shown) depending on the movement number of the mold.

Figure 3 is a process diagram for molding polyurethane foam.The manufacturing process for polyurethane foam involves injecting liquid into a mold that is placed on a trolley on rails and moving, in each of the process sections shown in the figure. Polyurethane foaming liquid is injected, the upper mold is fitted to the lower mold using the mold opening/closing guide 9, and the foaming hardening is completed through the heating process in oven b.
The roller 8 automatically opens the upper mold along the mold opening/closing guide 9, takes out the foam molded product 9, and with the upper mold open, continuously passes through the cooling process part d equipped with a quenching device. During this time, it is rapidly cooled by the mittens sprayed from the nozzle. Next, through the inspection process section ESL type agent application process section f,
In the temperature control process section Q, the temperature of the mold is adjusted before injection of the foaming liquid, and the process is repeated to the liquid injection process section to perform manufacturing.

The cooling method of this invention cools the inside and outside of the mold in the same dry fog state using a two-fluid nozzle while the hot mold after demolding passes through the cooling process section d, thereby causing a phenomenon of wetting on the inner surface of the mold. The basic method is to prevent the occurrence of However, depending on the shape of the mold, if there is no risk that the cooling mist on the outside of the mold will cause wetting on the inside of the mold, the diameter of the mist sprayed on the inside and outside of the mold can be changed, respectively. Cooled with mist of different particle sizes,
Use methods to reduce air consumption.

Of course, cooling the entire mold in a dry fog state has a greater cooling effect, but this requires higher air pressure and has the disadvantage of increasing air consumption. Therefore, depending on the merits and demerits of both, cooling using only dry fog or cooling using mist with different particle sizes is performed. FIG. 4 shows an example of a method of cooling the inner surface of the mold and the outer surface of the mold with a mist of different particles in a cooling schematic diagram of a piping route.

In the figure, 10 is a water tank and 11 is an air tank. Water is supplied through a strainer 12 using a cascade pump (CASCAt) 13 to respond to changes in pressure and water volume, and a needle regulating valve (
Adjust the flow rate and pressure of water with the pressure regulating valve (having a needle valve) 14 to obtain the required pressure and pressure. A two-fluid nozzle (abbreviated as A outer nozzle) that cools the outside of the upper die B (abbreviated as A outer nozzle) and a two-fluid nozzle (abbreviated as B inner nozzle )
Supply the required pressure water to BT. Air is supplied from an air tank 11 that holds the required pressure air to a set of B outer nozzles Bo and A outer nozzles AO through an air pressure reducing valve 17, to a set of B inner nozzles BI via an air pressure reducing valve 16, Adjust and supply the required pressure air to each. However, when forming the entire structure into a dry fog state (average particle size of 10μ or less), the same water pressure and air pressure are applied to both the set of B outer nozzle BO and A outer nozzle AO, and the set of B inner nozzle BI. is supplied, and an ultra-fine mist of water is sprayed inside and outside the heating mold to rapidly cool it. In the case of this dry fog formation (mist-like with an average particle size of 10μ or less), the water pressure is 0.5kMc.
...2. When the air pressure is 4 kg/cd or 5 kmcm2 and the spray conditions on the outside of the upper mold and the outside of the lower mold are to form a mist state with an average particle size of about 30 μm to 50 μm, the water pressure is 1.0 μm to 1.0 μm. 5kg/cm2, air pressure 3
．． It is set at 0 kmcm2, but water pressure 1
kMCm2 and air pressure of 3.0kMc...2 are more preferable.

In this example, the inner surface of the heating mold has a water pressure of 0.5k.
(If/Cm2, air pressure 4 kM cm2, spray in dry fog condition, upper mold outer surface and lower mold outer surface water pressure 1 kM cm2, air pressure 3 kMcnr)
The mold humidity, which was 100°C when sprayed in a mist state under condition 2, decreased to 37°C in 90 seconds by passing through the cooling process. Furthermore, the inner surface of the mold after cooling was completely dry, and there was no wetting due to dew condensation, and it was possible to use it as it was in the next process (release agent→liquid injection). Mochi theory, set of nozzles AO outside A of the lower mold and B of the upper mold
The cooling adjustment of the set of outer nozzles BO is performed by adjusting the scale (m'/h) of the needle valve 14, which regulates the flow rate of water, to increase or decrease the amount of water depending on the summer or winter. Also, if it gets too cold at night or in the winter, some of the nozzles in each set stop spraying and use a thinner set of nozzles.

In addition, in case the upper mold B becomes too cold,
A freely controllable valve is attached to the outer nozzle BO set, and the spray can be opened and closed even at -12= during operation. Further, the water pressure of the set of nozzles BI in B that cools the inner surface of the upper mold is adjusted by the adjustment screw of the water pressure reducing valve when the water does not cool down or becomes too cold. It goes without saying that the air pressure should be adjusted appropriately to the water pressure mentioned above.

Conventional method under the same quenching conditions in the above example (
The following table shows the results of a comparison of the amount of cooling water used between the cooling methods (methods 1 to 2) in the prior art section and the method of the present invention.

Comparison table of water consumption [Effect of the invention] As shown in the above example, the maximum heat dissipation effect can be obtained with the minimum amount of water, so the amount of cooling water used is reduced to 1/1 compared to the conventional method.
The maximum cooling effect can be obtained with a large saving equivalent to 30 to 1/600 and an extremely small amount of cooling water. Therefore, the amount of wastewater is extremely small, and there is no need for wastewater treatment measures, and there is no need to control the temperature using cooling equipment. In particular, it prevents water from entering the mold and preventing wetness from forming on the inner surface of the mold.
There is no need to wipe the inside of the mold, which was a bottleneck in the process. Therefore, it greatly contributes to making the process smoother and more efficient, improving the accuracy of the predetermined temperature of the mold before injection, improving quality, and reducing labor costs.

[Brief explanation of drawings]

Fig. 1 is a schematic front view showing a partial cross section of an example of a molding die; Fig. 2 is a schematic front view when the upper mold is open; Fig. 3 is a process diagram for molding polyurethane foam; FIG. 4 is a piping route and a cooling schematic diagram of an example of the cooling method of the present invention. 4 or A...lower mold 6 or B...upper mold BO...
・Two-fluid nozzle that cools the outside of the upper mold (abbreviated as B outside nozzle) AO...Two-fluid nozzle that cools the outside of the lower mold (abbreviated as A)
Outer nozzle) 81... Two-fluid nozzle that cools the inner surface of the upper mold (abbreviated as B inner nozzle)

Claims (1)

[Claims] (1) When cooling a foam mold, water pressure (kg/cm^2) and air pressure (kg/cm^2) are set to 1:
Supply it to a two-fluid nozzle at a ratio of 8 to 9 to form an ultra-fine mist (average particle size of 10 μm or less), and spray it on the inner and outer surfaces of the heating mold for rapid cooling, or ,
The above-mentioned ultra-fine mist is sprayed on the inner surface of the upper mold of the heating mold, and at the same time, on the outside of the lower mold and the upper mold, a two-fluid nozzle is used to apply water pressure and air pressure at a ratio of 1:3 to 2. A mist quenching method for a molding die, which comprises rapidly cooling a mold by spraying a fine mist (average particle diameter of 30 to 50 μm) formed by supplying the mold.