JPH056500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heating device for a T-die for a laminator.

(Conventional Technology) Conventionally, T-die lip heaters for laminators have been of an integrated type with uniform power density. For this reason, the temperature was lower at the end portions where a large amount of heat was radiated, and the temperature was higher at the center. For this reason, the temperature of the resin decreases toward the edges, and the thickness of the extruded film also differs. Furthermore, the temperature distribution changed due to changes in the outside air temperature, and the film thickness also changed accordingly.

(Problems to be Solved by the Invention) In view of the problems of the prior art, the present invention attempts to reduce the deviation in longitudinal temperature distribution of a T-die for a laminator.

(Solving Means by the Invention) A lip heater divided in the longitudinal direction is arranged in a T-die for a laminator, a temperature measuring device is provided in the T-die in each divided section, and based on the measured value by this device, This makes it possible to make the film thickness of the extruded resin uniform by controlling the temperature distribution to the desired pattern while compensating for thermal interference from the area where the resin is extruded.

(Example) This will be explained with reference to FIG. 1 is a T-die, and 2 is a resin film extruded from the T-die. Reference numeral 3 denotes a lip heater disposed in the lip heater section, which is divided into six divided lip heaters 3a, 3b, . . . 3f in the illustrated example. Each split lip heater is provided with a temperature sensor 4 such as a thermocouple, which is embedded in a hole provided in the T-die portion.

The temperature of the lip portion of each divided lip heater is detected by the temperature sensor, and the detected values θ ₁ to _{θ 6} are inputted to the temperature measuring amplifier 5 shown in FIG. In this microcomputer 6, a temperature pattern indicated by a dotted line as shown in Fig. 3 is set in advance.
The value is compared with the detected value, and power outputs U ₁ to _{U 6} proportional to the difference are given as the operating amount of the heater.

At this time, since there is thermal interference in the x-axis direction in FIG. 3, one manipulated variable Ui also affects the i-1th and i+1th temperatures. Therefore, if thermal interference is compensated for by calculating in advance the amount of heat entering and exiting from adjacent sections and correcting the manipulated variable, a highly accurate temperature distribution can be realized.
Split lip heater 3i (i=a, b, c, d, e,
In f), when the temperature θi of this portion is lower than the target temperature θir, it is sufficient to apply a manipulated variable of Ui=Ki (θir−θi) to the lip heater. However, at the same time the split lip heater
From the manipulated variables of 3 _i-1 and 3 _i+1 , q _i(i-1) = a _i(i-1) (θ _2-1 −θ _i
),
Since the amount of heat of q _i(i+1) = a _i(i+1) (θ _i+1 − θi) is flowing in, if θi is increased, q _i(i-1) , q _i(i+1) decreases, and the temperatures of θ _i-1 and θi increase. Therefore, the amount of operation is determined by correcting Ui to Ui+k _i(i-1) q _i(i-1) +k _i(i+1) q _i(i+1) in advance.

In other words, the correction formula for Ui = Ui + k _i(i-1) q _i(i-1) +k _i(i+1) q _i(i+
1) =Ki(θir+θi)+k _i(i-1) a _i(i-1) (θ _i-1 −θi)+k _i(i+1) a _i(i+1) (θ _i+1 −θ _i-2 ) =Ki(θir−θi)+k _i(i-1) a _i(i-1) θ ₂ −(k _i(i-2) a _i(i-2) +k _i(i+1) a _i(i+1) ) θ _C +k _i(i+1) a _i(i+1) θ _i+1 Therefore, b _i(i-1) , b _ii , b _{i(i +1)} is b _i(i-1) =k _i(i-1) a _i(i-1) b _ii =+(k _i(i-1) a _i(i-1) +k _{i(i+ 1)} a _i(i+1) ) b _i(i+1) = k _i(i+1) a _i(i+1) . Thus, the temperature of each part
It is possible to control the desired pattern as shown by the dotted line in the figure. However, a _i(i-1) and a _i(i+1) are constants determined by the thermal characteristics of the T-die, and Ki is a proportional constant for deviation, k _i(i-1) and k _{i(i+1 )} is a constant to compensate for thermal interference.

Note that the deviation can be further reduced by making the division thinner toward the ends.
Further, as shown in FIG. 4, by changing the power density distribution of the heater for each divided lip heater, it is possible to effectively deal with differences in the amount of heat radiation depending on the location.

(Effect) A lip heater divided in the longitudinal direction is installed in the T-die of the laminator, and a temperature measuring device is installed inside the T-die in each divided section, and based on the measured value by this device, the thermal Since the temperature distribution can be controlled to the desired pattern while compensating for interference, it has become possible to make the thickness of the extruded resin film uniform.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a T-die heating device according to the present invention. FIG. 2 is a block diagram of the control device. Figure 3 is T
Diagram of temperature distribution in the longitudinal direction of the die. Figure 4 is a power density distribution diagram of the heater. In the figure; 1...T die, 2...resin film, 3
... Lip heater, 4 ... Temperature sensor, 5 ...
Temperature measurement amplifier, 6...microcomputer.

Claims (1)

[Claims] 1. A lip heater divided in the longitudinal direction is installed in the T-die of the laminator, and a temperature measuring device is installed in the T-die in each divided section, and based on the measured value of the temperature measuring device, the temperature from the adjacent section is calculated. A T-die heating device for a laminator, which is characterized by compensating for thermal interference and controlling temperature distribution in a desired pattern to make the film thickness of extruded resin uniform.