JPS61261022A - Manufacture of polymer film - Google Patents

Abstract

PURPOSE:To enable to adjust uniformly a thickness of a film in a widthward direction of the film, by performing adjustment of an opening of a die lip by a lip adjustment bolt expanding and shrinking through heating and cooling of a heater block with a fin. CONSTITUTION:A die bolt heater 5 is inserted into the inside of a heater block 4 with a fin and an opening of a lip 2 is adjusted by making respective lip adjustment bolts 3 expand and shrink through heating and cooling of the die bolt heater 5. At the time of extrusion of a polymer film through a lip 2 opening by casting a thermoplastic polymer into a die body 1 through a polymer casting port 7, adjustment of a thickness of the film is performed by thermal expansion and shrink of the lip adjustment bolt 3 whose temperature adjustment has been performed by the die bolt heater 5. In consequence of the above, dapples in the thickness of the film can be adjusted extremely swiftly by corresponding to the dapples in the thickness of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a polymer film, and more specifically, the thickness in the width direction of the film is determined by determining the thickness of the film in the width direction of the die lip opening v4In.
The present invention relates to a method for manufacturing a polymer film having a uniform thickness in the width direction by performing #14!1 using a lip adjustment bolt that expands and contracts by heating and cooling a finned heater block.

(Prior art) Polymer films are required to have a uniform thickness in the width direction, and Hashi's method has been proposed as a method for making the thickness uniform.One of the methods is lip adjustment of the spacing between die openings. There is a method of mechanical adjustment using bolts.However,
This lip lJ [work requires a skilled worker, must be carried out in a narrow work area limited by equipment surrounding the die, and in a high-temperature atmosphere, and because it is done manually, there are limits to the adjustment accuracy. . On the other hand, JP-A-49-135743
There is an automatic adjustment method using a rotary drive device, as disclosed in Japanese Patent Application Laid-open No. 51-115595, but according to the study of the present inventor, this method involves the transmission of vibrations from the rotary drive to the die, which reduces the amount of melt that is discharged from the die. It was found that the product was subject to vibration and the film was uneven in thickness, making it difficult to use in production.

Another method that has been proposed recently is to enclose the lip adjustment bolt from the outside with a heater block, expand and contract the lip adjustment bolt by heating the heater block, and control the amount of polymer extruded from the lip opening. There is a way to make it uniform across the entire width. However, there are various problems with this technique of equalizing the discharge amount of molten polymer by expanding and contracting the lip g straightening bolt due to heating of the heater block.

Specifically, these problems include the following two points.

First, since the lip adjustment bolt is surrounded by an external heater block, it takes a long time to adjust the thickness of the thin part of the film and is difficult. That is, this adjustment operation initially maintains the voltage of all external heater blocks at a predetermined voltage, and then during film production, increases the voltage in thicker parts of the film and decreases the voltage in thinner parts of the film. The thickness of the film will be uniform. 5.III! ! do. In order to make the thin part of the film the same thickness as the surrounding area, it is necessary to lower the voltage, but since the external heater block has a larger volume than the adjustment bolt, the heat capacity is large, and the heater Lowering the voltage to the specified voltage also slows down the cooling of the heater block and takes a long time to adjust the uneven thickness.

The second drawback is that the responsiveness of heating adjustment and cooling adjustment is large (different), which poses a major hindrance to establishing an automatic control loop in automatic production.

[Purpose of the invention]

The inventor of the present invention solved the above problem (as a result of intensive research, by making the heater block with fins!I!
The cooling speed of the straightening bolts has been increased, and by forcibly cooling only the corresponding finned heater blocks when cooling is required, the cooling speed can be significantly faster than with conventional heater gooks, which allows for faster cooling in a short time. heat ir m a
*Lip f! Adjusts the opening of the lip by expanding and contracting when heated by an external heater block, which can make the length of the combined film uniform in the width direction! Succeeded in solving the technical problems of the Ill bolt method.

The purpose of the present invention is to make the thickness of the film uniform in the width direction +lS
An object of the present invention is to provide a method for producing a polymer film with +1 improvement.

[Structure of the Invention] According to the present invention, when a molten polymer is extruded from a die to form a film, the thickness in the vertical direction of the film is adjusted by adjusting the opening of the die lip, and the adjustment is performed using a finned heater heater. Lips that expand and contract when heated and cooled! This is accomplished by bolting.

Hereinafter, the present invention will be explained in detail with reference to the accompanying drawings. .

As shown in FIG. 1, the tips of a large number of glues arranged in parallel toward the opening of the lip (2) on the upper part of the die body (1) are fixed to the back of the die lip (6).

A Guivolt heater (5) is inserted inside the finned heater block (heater block with fins), and this Daivolt heater (5)
) by heating and cooling each lip adjustment bolt (3)
Adjust the opening of the lip (2) by expanding and contracting it! I do. In the figure, (7) is a polymer injection port.

Inject the thermoplastic polymer from the polymer injection port (7) into the die body (1).
) and extrude the polymer film from the opening of the lip (2), the thickness of the film is determined by thermal expansion and contraction of the lip adjusting bolt (3) whose temperature is adjusted by the Gui bolt heater (5).

At that time, the lip adjustment bolt is expanded by heating the heater block by increasing the voltage of the Gui bolt heater, and the lip and Jl adjustment bolts are heated smoothly from K. On the other hand, the lip adjustment bolt The shrinkage of the film is also accelerated by the heating pump equipped with a tween, and as a result, the uneven thickness of the film can be adjusted extremely quickly.

〔Effect of the invention〕

The present invention uses a finned heater block as the heater block, which can increase the contact area with the outside air and increase heat transfer, as well as increase the cooling rate and responsiveness. The height can be adjusted uniformly in a shorter time than before.

〔Example〕

The present invention will be further described below with reference to its implementation.

Example D The temperature change responsiveness of B was measured.

Heater boot block dimensions: 20 m x 40 @ x 200 m length Fin dimensions: 20 m The electric power was measured, and the temperature was converted from the measured value.

The changes over time in the salinity at the thermocouple mounting position were measured when the voltage of the cartridge heater was increased from 40V to 6°V and when it was decreased from 60V to 40V.The results are shown in Table 1.

Table 1 Based on the results shown in Table 1, the cartridge heater voltage was increased in this finned heater boot tank. It can be seen that the time required for the temperature of the heater block body to become constant is almost the same when the temperature is lowered and the time required for the temperature to change is even shorter.

Comparative Example 1 Using a heater block without fins but with the same dimensions as in Example 1, the temperature at the thermocouple installation position when the heater voltage was increased from 40 V to 60 V in the same manner as in Example 1. The changes over time were measured.゛The results are shown in Table 2.

Table 2 From the results in Table 2, it can be seen that the temperature change response took a long time of 70 minutes, and the response was inferior to that in Example 1.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 11i2 is a perspective view of a finned heater block. (1) is the die body (2) is the lip (3) is the lip g! I port (4) is a heater block with fins (5) is a die bolt heater (6) die lip (7) resin injection port Akira 1 port

Claims (1)

[Claims] In a film manufacturing method in which a molten polymer is extruded through a die and the thickness of the film in the width direction is adjusted by adjusting the opening of a die lip, the opening of the extrusion die is expanded and contracted by heating and cooling a finned heater block. A method for producing a polymer film, the method comprising adjusting the film using an adjusting bolt.