JPS60236719A - Cooler for thermoplastic resin - Google Patents

Abstract

PURPOSE:To prevent ruffling and rolling on the surface of a cooling fluid providing a porous current shaping body in a passage thereof which flows cooling a metal resin. CONSTITUTION:A thermoplastic resin 4 which is extruded as melted from a die 2 is introduced into a slit 3 of a cooler where a cooling fluid is fluidized and then, discharged via the slit 3. A porous current shaping body 6 is provided in a fluid passage within the device 1 between a fluid introducing section 5 and the thermplastic resin 4. The ruffling and the rolling on the liquid surface of the fluid is prevented to obtain a uniform water flow free from vertical ruffling with respect to the thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for a thermoplastic resin, and more particularly to a device that prevents ripples and fluctuations in the surface of a cooling fluid in a cooling device for a thermoplastic resin using a fluid such as a water cooling method.

Conventionally, when producing thermoplastic resin sorts or films by the T-die method or the inflation method, the method of cooling the molten film extruded from the die of the extrusion plate was forced room cooling by blowing air. A water-cooling method that involves contact with a liquid such as water is known. However, in the case of the air cooling method, the cooling effect of the thermoplastic resin is insufficient and the cooling rate is low, so crystallization tends to occur and it is impossible to obtain a sheet or film 1 with excellent transparency.

On the other hand, the water cooling method has high cooling efficiency, but when the molten resin film comes into contact with water, the water in that area evaporates and boils, causing local ripples and shaking of the water surface, resulting in uneven cooling and Cooling will be insufficient. As a result, the thermoplastic resin sheet or film has drawbacks such as generation of haze salt, uneven thickness, and reduction in transparency and surface gloss.

In order to improve these drawbacks caused by the water cooling method, methods using a mist or foam cooling fluid have been proposed. According to this improved method, although the cooling efficiency is improved, a good product cannot be obtained. Also, a method has been proposed in which a molten resin film is introduced into a slit through which cooling water flows, but in this case too, pruning of the water surface is unavoidable.
Can't get a good product. Note that if a pruning prevention plate or water flow control plate is used to prevent pruning of the water surface and turbulence of water flow, the flow rate of cooling water cannot be made sufficiently fast, making it difficult to perform high-efficiency and high-speed molding. I can't.

An object of the present invention is to provide a cooling device for thermoplastic resin that eliminates such drawbacks.

That is, the present invention is directed to a thermoplastic resin cooling device that is located below a die for extruding a thermoplastic resin in a molten state and cools the molten resin by bringing it into contact with a flowing fluid. This is a thermoplastic resin cooling device characterized by providing a porous flow regulator in the channel.

To explain the apparatus of the present invention with reference to the drawings, FIG. 1 shows the state in which a cooling apparatus 1 used for manufacturing thermoplastic resin sheets or films by the T-die method is used. The device 1 is located below the die 2 and has a slit 3 at the center of the bottom of the device 1, and the thermoplastic resin film 4 extruded from the die 2 in a molten state is introduced into the slit 3. . A lip heater may be used for the tie if necessary.A fluid for cooling the resin film 4 flows through the device 1 and is discharged from the device through the slit 3. is introduced into the device 1, but the introduction part is usually
It is located near the side wall of the device 1. In the present invention, a porous fluid regulator 6 is further provided in the fluid flow path in the device 1, and the fluid regulator 6 is made of thermoplastic resin 4 (the resin is then slit) to be supplied to the fluid introduction section 5 and the device 1. 3).

The flow regulator 6 is made of a porous material, and is made of a wire mesh (for example, 1
0 to 200 mesh) or folded mesh materials; non-woven materials such as synthetic fibers, natural fibers, and metal fibers; resin wrappers with open cells, sintered materials, etc. are used. Among these, wire mesh and nonwoven fabric are suitable materials.

The porous fluid regulator can be formed by using the material having an appropriate thickness as it is, by laminating two sheets of material, or by stretching the material on a frame.

By providing the flow regulator 6 in the fluid flow path, ripples and fluctuations of the fluid surface are prevented, and a uniform water flow without ripples perpendicular to the film-like thermoplastic resin can be obtained. By providing multiple flow regulators (2 to 10 layers, 3 layers in the illustrated case), it is possible to achieve even greater effects such as increasing the flow rate.

Next, an example of manufacturing sheets and the like using the cooling device of the present invention will be specifically described. The slit 3 in the rice cooker is usually 1 to 101 mm thick. The length is about 5 to 100 capitals. In addition, the larger the amount of water in the cooling fluid that flows through the device 1, the better the cooling effect and the higher the production efficiency of the thermoplastic resin sheet or film. It should be as low as possible, and generally above J77 is preferred.

When the water level reaches 10, boiling spots, haze spots, and curls occur on the resulting sheet or film, and the total haze also becomes high, which is undesirable. The film-like thermoplastic resin is mainly cooled when passing through the slit.

That is, the cooling fluid flows in parallel on both sides of the film-like resin, and is efficiently cooled. Note that it is desirable that the flow rate of the cooling fluid be close to the traveling speed of the film-like resin.

The cooled n-shaped resin is then sent to a water tank 7. This water tank 7 is located below the device 1, and as shown in the figure, a clamping pressure II-rule 8 is arranged to clamp the resin film before the cooling fluid forms a turbulent flow. Press down on the sheet surface!
) 4 jf, '413'! What? At the same time, each time the film is driven at a constant speed, the running speed of the film-like 4111 oil is kept constant. 2 mlor or a combination of these - 1! '-t:: J, may be used. In the figure, 9 is a take-up roll, 10 is an overflow plate, and 11 is a cooler.

12 is a pump.

Figure 2 shows the lp! thermoplastic resin film produced by inflating and nosion molding. This figure shows the usage status of the cooling device 1 used for construction. In the apparatus 1 in this case, the cylinder 3' provided at the center of the apparatus corresponds to the slit 3 in the apparatus shown in FIG. Also, the inflation fill J\(bubble) 4' extruded from the die 2 is I+',! It corresponds to the thermal iiJ plastic resin 4. The device 1 is located at the top of the tie 2, and the bubble 4' extruded from the die 2 is placed in the cylinder 3'.
), to be reprinted.

Fluid for cooling the baffle is stored in this device 1, and fluid is introduced into the device 1 from a fluid introduction portion 5 located near the side wall of the device 1. cylinder 3
′ of 10 Oi: f 3 a is the side wall of the device [end 1 a, J
: Since the height is also low, the fluid overflowing from the upper end 3a is between the inner wall of the cylinder 3' and the baffle 4'. fi and is discharged outside the device. In this case, the upper end 3a of the cylinder 3'
A fluid guide such as gauze or bleach is provided along the inner wall.

The porous fluid regulator 6 is provided in the fluid flow path as in the case of FIG. 1, and is formed in an annular shape so as to surround the cylinder 3' as shown. In this case, a bottom plate 13 is attached to the outer wall of the cylinder 3' to prevent the fluid from flowing without passing through the fluid regulator. As in the case of Fig. 1, by providing multiple flow regulators (2 to 10 times, three times in the case shown), a uniform water flow without ripples perpendicular to the inflation film 4' can be created. can be obtained effectively. In the figure, it is a 140 air ring.

By using the apparatus of the present invention, it is possible to obtain sheets with excellent transparency and surface gloss when manufacturing sheets and films using various thermoplastic resins as raw materials.
Wear. Moreover, these sheets and the like do not have minute irregularities, wrinkles, curls, etc. on the surface of the Heiss spots 9, and are evenly rounded. Furthermore, since the amount of cooling fluid used can be increased during cooling, the cooling effect of the thermoplastic resin is good. Therefore, the production speed of the product can be increased, and relatively thick sheets and the like can be formed.

Next, an example of use of the device of the present invention will be shown.

Example of use The cooling device shown in Figure 1 (3 sets of porous rectifying plates made by folding 40 mesh wire mesh twice are installed in the fluid flow path in the water tank parallel to the molten resin film at 20 mesh intervals, A polypropylene sheet was manufactured using a slit width of 3 mm and a slit height of 30 mm. That is, polypropylene (density 0
．． 91 g/cm3. Melt Indj Sox 2.0g
/10 minutes) at a resin temperature of 235°C using a T-die extrusion device (extruder screw 65 dragon φ, L, /D = 28.Die width 60
0n, die lip opening degree 1.50). The extruded molten resin film is sent to the above cooling device, and cooling water (4
The water level was maintained at 51° C.) and the water was introduced into the slit of the device, where it cooled and solidified, and then taken off at a rate of 15 m/min to obtain a transparent polypropylene sheet with a thickness of 0.25 m.

The obtained sheet has no haze ring and is transparent (haze 10
%).

Comparative Example A polypropylene sheet was obtained in the same manner as in Example except that a water flow control plate was used instead of the rectifying plate provided in the fluid flow path of the cooling device.

In this case, since undulation of the cooling water surface is unavoidable, the obtained sheet has severe haze rings and transparency (haze 12
20%) and was non-uniform.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the apparatus of the present invention in use. 1...Cooling device, 2...Gui, 3...
····slit.

Claims (3)

[Claims] (1) In a thermoplastic resin cooling device that is located below a die that extrudes a thermoplastic resin in a molten state and cools the molten resin by bringing it into contact with a flowing fluid, the fluid flow path within the device is porous. A thermoplastic resin cooling device characterized by being equipped with a flow regulator. (2) The device according to claim 1, wherein multiple porous fluid regulators are provided between the fluid introduction part to the cooling device and the thermoplastic resin supplied to the device. (3) The device according to claim 1, wherein the porous fluid regulator is a net-like or non-woven material.