JPH0630425Y2 - T-die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a synthetic resin molding apparatus such as a T-die for extruding a molten synthetic resin into a sheet shape or a film shape.

(Prior art and its problems) FIG. 3 is a sectional view showing a T-die of a conventional synthetic resin molding apparatus, and FIG. 4 is a BB sectional view of FIG. 1, a melt synthetic resin manifold 2 extending in one direction is provided, and a planar passage 3 extending below the manifold 2 is further provided. A pair of lips 4, 5 are fixed and supported on the lower surface of the die body 1 by bolts 6 and differential bolts 7 in order to adjust the distance between the lip lands 8.

In addition, a plurality of divided body heaters 16 are arranged on both sides of the die body 1 so as to fill the width of the die body 1, and the die body 1 is kept at a predetermined temperature to prevent hardening of the molten resin.

Incidentally, 10 is a clean roll provided below the die body 1, and 11 is a silicone rubber roll.

As shown in FIG. 4, a pair of forming plates (inner deckles) 12 are movably provided on both sides of the planar passage 3 in order to adjust the width of the film or sheet to be formed. An operation rod 13 made of an iron rod having a diameter of about 4 mm is connected to the outer surface of the, and the operation rod 13 is extended to the outside of the die body 1,
By operating this projecting end, the forming plate 12 is moved left and right to adjust the width of the planar passage 3 through which the molten resin passes. The sealing rod (inner deckle bar) 14 of the lip land portion 8 is made of, for example, a piano wire, and moves left and right together with the forming plate 12 to seal the lip land portion 8.

In this apparatus, the molten resin is sent from the molten resin pressure-feeding device through a supply pipe 15 usually provided at the center of the T die, spreads to the full width in the manifold 2, and further at the lip land portion 8 at a predetermined width. Since it becomes thick and is extruded,
In order to make the flow of the molten resin smooth during this time, the T-die is heated to a predetermined temperature by the main body heater 16 which is divided into a plurality of pieces in the longitudinal direction. The reason for the division into a plurality of parts is that a temperature difference occurs between the upper part of the T die and the lip part, so it is necessary to perform appropriate temperature control in order to keep the entire part at a uniform temperature.

However, the thickness of the film or the like is regulated by the lips 4 and 5 forming the lip land portion 8. The lips 4 and 5 are far from the main body heater 16 and, for example, a material having a high thermal conductivity to the die main body 1. Even if is used, temperature changes due to external factors cannot be avoided.

As a result, the extruded film or the like has uneven thickness due to the temperature change of the lips 4, 5.

An object of the present invention is to solve the above problems and provide a T-die capable of extruding a film or sheet having a uniform thickness from a molten resin.

(Means for Achieving the Object) In order to achieve the above-mentioned object, in the T die of the synthetic resin molding device, a plurality of parts are divided on both sides of the die body 1 that receives the molten resin pumped from the molten resin pumping device. Main body heaters 16 and 16 provided on the both sides, and lip heaters 17 and 17 provided on both sides of the lips 4 and 5 for extruding the molten resin into a film by dividing the same number as the main body heater 16 respectively. , The die body 1
Bias values of the temperature detectors 22 that are inserted into the inside of the main body heater 16 and the same number as the main body heater 16 and the detection force of the thickness gauge 21 that detects the thickness of the extruded film are used. To adjust to the temperature detector
The same number of bias adjusters 20 as 22, the set values of the temperature setter 18 for setting the temperatures of the die body 1 and the lips 4, 5 and the temperature detector 22 adjusted by the bias adjuster 20.
Main body heater 16 and lip heater 17
And a temperature controller 19 for controlling the temperature.

(Operation) As described above, the main body heater 16 and the lip heater 17 are controlled by the temperature adjuster 19 to the constant temperature set by the temperature setter 18.
However, the thickness of the extruded film is changed due to the temperature unevenness in the lateral direction of the die body 1 and the subtle temperature unevenness of the lips 4 and 5.

Therefore, the bias value of the temperature detector 22 is adjusted by the detection force of the thickness gauge 21 that detects the thickness of the film to adjust the detection force according to the temperature unevenness, and the temperature is adjusted by the adjusted detection force. A regulated output of the container 19 is controlled to realize a uniform temperature distribution, and a film having a predetermined thickness is always extruded.

(Embodiment) FIG. 1 is a sectional view of a T-die of the present invention, and FIG. 2 is a circuit block diagram of temperature control.

1 is the same as the conventional example shown in FIG. 3 except for the lips 4 and 5, so that only the parts different from the conventional example will be described below.

Each of the lips 4 and 5 has a heater on the outer bottom.
Lip heaters 17, 17 divided into the same number as 16 are provided.

FIG. 2 is a circuit block diagram relating to the control of the main body heater 16 and the lip heater 17. The body heater 16 and the lip heater 17 are configured to be temperature-controlled by the temperature controller 19 to the temperature set by the temperature setting device 18. The temperature to be maintained varies depending on the type of synthetic resin and the thickness of the extruded film, etc.
It is set at 18.

On the other hand, the die body 1 has a temperature detector 22 such as a thermocouple.
Is inserted into a hole bored from the side surface, and the compensation lead wire of the temperature detector 22 is connected to the bias adjuster 20. The bias adjuster 20 receives the detection force of the thickness gauge 21, and the output thereof is input to the temperature adjuster 19.

Next, the operation of adjusting the temperature of the T-die will be described.

First, the temperature setting device 18 sets an optimum temperature depending on the type of resin and the thickness of the film to be extruded. This set value is calculated by the temperature controller 19 for calculating the temperature setting of each part of the main body heater 16 and the lip heater 17 which are divided in order to prevent the temperature of the central portion for heat dissipation of the T die and the temperature at both ends from being different. ,
Heating power is supplied to each of the main body heater 16 and the lip heater 17 to keep the temperature distribution in the horizontal and vertical directions of the T-die constant.

Regarding this temperature distribution, the extruded film becomes thick when the temperature is high, and becomes thin when the temperature is low, so that a constant temperature distribution is always required.

The above-mentioned temperature distribution is detected by a temperature detector 22 inserted into the hole of the die body 1 to a certain depth, and the compensating lead wire of this temperature detector 22 measures the thickness of the extruded film. The resistance value is corrected by the bias adjuster 20 by the detection force of the thickness gauge 21 and is input to the temperature adjuster 19 to adjust the temperature unevenness that causes the thickness unevenness.

(Effects of the Invention) As described above, the temperature of the lips 4 and 5 follows the temperature of the die body 1, and even if the temperature unevenness in the transverse direction of the T die occurs and the thickness unevenness occurs in the extruded film, it immediately occurs. The bias adjuster 20 of the temperature detector 22 operates to adjust the temperature distribution of the T-die and always extrude a film having a constant thickness.

Further, when changing the extrusion conditions such as changing the type of resin, the temperature distribution in the lateral direction is automatically adjusted by simply changing the set temperature, and thus the change adjustment is easy.

[Brief description of drawings]

1 is a sectional view of the T-die of the present invention, FIG. 2 is a block diagram of the same temperature control circuit, FIG. 3 is a sectional view of a conventional T-die, and FIG. 4 is a BB sectional view of FIG. . 1: die body, 4, 5: lip, 16: body heater, 1
7: Lip heater, 19: Temperature controller, 20: Bias controller, 21: Thickness gauge, 22: Temperature detector.

Claims (1)

[Scope of utility model registration request] 1. A T-die for a synthetic resin molding apparatus, wherein a plurality of main body heaters are provided on both sides of a die body for receiving the molten resin pumped from the molten resin pumping apparatus, and the molten resin is in a film form. Lip heaters, which are divided into the same number as the main body heaters on both sides for extruding, and temperature detectors which are inserted into the die main body and have the same number as the main body heaters, Set the same number of bias adjusters as the temperature detectors that individually adjust the bias value of each temperature detector by the detection force of the thickness gauge that detects the thickness of the film, and the temperature of the die body and the lip. Temperature of the main body heater and lip heater by the set value of the temperature setter and the detected force of the temperature detector adjusted by the bias adjuster. T-die, characterized by comprising a temperature controller for regulating.