JPH04105911A - Calendering of resin - Google Patents

Abstract

PURPOSE:To permit variations in the thickness of an article film to be controlled without lowering productivity by a method wherein the amount of molten resin staying on mill rolls is measured, the amount of the molten resin supplied to the mill rolls is controlled based on the measured value and the amount of the molten resin staying on the mill rolls is retained at a predetermined value. CONSTITUTION:A molten resin is supplied from the first mill rolls 1A and 1B of a kneading machine through a strainer 2 and then through the second mill rolls 3A and 3B thereof into a calender device 4, whereby the resin is rolled into an article film. A sensor 5 is provided to detect the amount of the molten resin staying on the second mill rolls 3A and 3B, this output is fed into an arithmetic unit 6, the corrected amount of the molten resin to be supplied to the strainer 2 is computed and fed into a control unit 7 and the gap of a cutter 9 of a cutting device is changed. In this way the amount of the molten resin staying on the mill rolls 3A and 3B is adjusted to be always in a predetermined range, variations in the temperature of the molten resin supplied to the calender rolls are controlled and variations in the thickness of the article film are also improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for producing a film with good productivity and high thickness accuracy in calendering of a resin such as soft vinyl chloride. Concerning a calendar processing method.

[Prior Art] FIG. 2 shows a conventional calendering line for resin such as vinyl chloride resin. This line configuration is most commonly employed in calendering of resins.

In this conventional line configuration, molten resin is supplied from a kneader 1 such as an axial continuous mixer or a planetary extruder to mill rolls 3A and 3B, passes through a strainer 2 with kneading, extrusion, and filter functions, and then passes through a calender roll 4A.
, 4BJ2, calendar roll 48, 484
Rolled with gaps of B, 4C, 4C, and 4D.

A resin cutting mechanism (not shown) consisting of a cutting canter and a motor is installed on the mill roll 3B. This makes it possible to adjust the amount of resin supplied to the top bank of the strainer and calender.

In this line configuration, the temperature of the molten resin supplied from the strainer 2 onto the calender rolls 4Δ and 4B is homogenized due to the kneading effect inside the strainer 2, and as a result, variations in the thickness of the product film are suppressed. However, on the other hand, when changing the type of raw material resin, it is difficult to connect different types of raw materials with a small amount of mixture on the calender roll, which may temporarily slow down the production speed, or change the type of raw material resin. It is also a factor that reduces productivity, such as increasing the amount of raw materials mixed together and increasing loss of raw materials.

FIG. 3 shows a calendering line that eliminates the above drawbacks of the line configuration shown in FIG. 2.

In this line configuration, the molten resin is supplied from a kneader 1 having a feed rate adjustment mechanism such as a twin-screw continuous kneader or a foot extruder to a strainer 2, and then passed through mill rolls 38 and 3B. It is fed onto calender rows 4A and 4B and rolled.

The mill roll 3B is provided with a resin cutting mechanism (not shown) consisting of a cutting cylinder and a motor so as to be able to adjust the amount of resin supplied to the top bank of the calendar.

This line configuration has the advantage that it is possible to easily change the raw material resin without reducing productivity.

However, in this line configuration, the temperature of the molten resin supplied onto the calender rolls 4A and 4B is more likely to fluctuate than in the case where the molten resin is supplied from the strainer 2 in the 2M calendar line configuration, and as a result, the =b
The disadvantage is that it is easy to change.

[Problems to be Solved by the Invention] As mentioned above, the line configuration for calendering resin shown in FIG. 3 has the advantage that changing the raw resin is easy and does not reduce productivity. However, on the other hand, it has the disadvantage that the thickness of the product film tends to fluctuate.

The present invention aims to provide a resin calendering method that can maintain the above-mentioned advantages while suppressing the disadvantageous variation in thickness of the product film.

(Means for Solving the Problems) The present invention provides a resin calendering method in which a molten resin is sequentially passed through a kneader, a strainer, and a mill roll, and then supplied to a calender roll to form a rolled film. It is characterized by measuring the amount of molten resin staying on the mill roll, controlling the amount of molten resin supplied to the mill roll based on the measured value, and thereby maintaining the amount of molten resin staying on the mill roll at a constant level. .

[Effect]

In the calender line shown in FIG. 3, the thickness of the product film tends to fluctuate because the temperature of the molten resin supplied from the mill roll 3B to the calender rolls dM and 4Bj- fluctuates easily. Therefore, it is necessary to keep the temperature of the molten resin supplied to the calender roll constant in order to suppress variations in the thickness of the product film.

As a result of intensive analysis of the temperature fluctuations of the molten resin supplied from the mill rolls to the calender rolls, the present inventor found that fluctuations in the amount of molten resin retained in the mill rolls caused the temperature of the molten resin supplied from the mill rolls to the calender rolls. I found that it had a big impact.

Therefore, in the present invention, the amount of molten resin remaining on the mill roll is measured, and based on this measured value, the change J in the temperature of the molten resin supplied from the mill roll to the calender roll as a result of the mill is suppressed. Therefore, variations in the thickness of the product film formed using the calendar rolls are suppressed.

The method for adjusting the amount of molten resin supplied to the mill rolls is as follows: () A twin-screw continuous kneading machine typified by the twin-screw continuous kneading machine FCM manufactured by Farrell Co., Ltd. or a planetary extruder, etc.
Method of using a kneading machine which itself has a resin supply amount adjustment mechanism (2) A method of using a separate mill roll as a kneading machine, installing a cutting device in combination with it, and adjusting the resin supply amount with this combined device, etc. Conceivable.

Further, when attempting to control the thickness of the product film according to the present invention, it is important to pay particular attention to maintaining the amount of tosophanks of the calendar constant. That is, the operation should be carried out so that there is as little variation in the amount of the top bank of the calendar as possible. Specifically, for example, the amount of the 1-soph bank of the calendar is measured, and based on that measurement value, It is appropriate to adopt a foot control method to adjust and control the amount of resin supplied to the bank.

〔Example〕

An embodiment of the present invention will be explained with reference to FIG.

This example relates to a calender pressurization method for resin such as soft vinyl, and includes kneading, extrusion, and filtering functions from the first mill rolls IA and IB as a kneading machine having a feed rate adjustment mechanism through a conhair 10. The molten resin in the form of a lip is supplied, and the molten resin is further transferred from the same strainer 2 to the con hair 1.
1 to the second mill rolls 3A and 311, and from the mill roll 3B to the upper calender rolls 4A and 4 [1] of the calender device I, which is composed of four inverted I1-shaped wooden calender rolls, via the conhair 12. Ru. The molten resin is distributed between the calender rolls 4Δ and 4B,
A product film is formed through the gap between the calender roll 4B and the calender roll 4C provided below, and further through the gap between the calendar roll 4C and the calender roll 4D provided below.

A resin cutting mechanism (not shown) consisting of a cutting canter and a motor is installed on the mill roll 3B so as to adjust the amount of resin supplied to the top bank of the calendar.

In this embodiment, the first mill rolls IA, I
A pair of disc-shaped cutters 9 rotating in contact with one of the mill rolls 1B and spaced apart in the axial direction of the mill roll IB, and a motor 8 for changing the interval between the cutters 9 are provided. The cutter 9 and motor 8 constitute a cutting device. The motor 8 is controlled by the output of the control device 7 of the cutting device.

In addition, in this embodiment, the second mill roll sheath,
A sensor 5 for measuring the amount of molten resin remaining at 310- is provided, and the output of the sensor is input to the arithmetic unit 6. The calculation device 6 calculates a correction amount for the amount of molten resin to be supplied to the strainer 2 based on the deviation between the preset amount of resin retained in the mill roll and its measured value, and sends the correction amount to the control device 7 of the first mill roll cutting device. The calculation result is output and the interval between the cutters 9 of the cutting device is changed.

As a result, the amount of molten resin supplied to the second mill rolls 3A, 3B via the strainer 2 is adjusted so that the amount of molten resin staying on the second mill rolls 3A, 3B is always kept within a certain range. Ru.

As a result, fluctuations in the temperature of the molten resin supplied from the second mill roll 3B to the calender rolls are suppressed, and fluctuations in the thickness of the product film are also improved.

In the above embodiment, a mill roll with a cut-out device is used as a kneading machine with a feed rate adjustment mechanism, but this kneading machine may be a continuous kneading machine, a planetary extruder, etc. A kneader having a resin supply amount adjustment mechanism may also be used. Furthermore, as shown in Fig. 1, a calender device consisting of four inverted wooden calender rolls is used, but at least three
As long as the calendar device is composed of more than one roll, it can be used regardless of its configuration or the number of rolls.

[Effects of the Invention] In a resin calendering method in which a molten resin is sequentially passed through a kneader, a strainer, and a mill roll, and then supplied to a calendar roll to be rolled into a film, the amount of molten resin retained on the mill roll can be reduced. Based on the inventor's findings that fluctuations greatly affect the temperature of molten resin supplied from mill rolls to calender rolls, in the present invention, the amount of molten resin retained on the mill rolls is measured, and based on this By controlling the amount of molten resin supplied to the mill rolls, the amount of molten resin staying on the mill rolls can be kept constant, thereby suppressing fluctuations in the temperature of the molten resin supplied from the mill rolls to the calender rolls. Therefore, the molten resin is mixed into a kneader,
~ In addition to maintaining the advantage that switching of raw resin is easy and does not reduce productivity in a resin processing method in which the resin is passed sequentially through a laner and a mill roll and then supplied to a calendar roll to be rolled into a film, the mill mouth 10,
]L12...conhair.

Claims (1)

[Claims] In a resin calendering method in which the molten resin is sequentially passed through a kneader, a strainer, and a mill roll, and then supplied to a calendar roll to form a rolled film, the amount of molten resin retained on the mill roll is measured, and the method is based on the measured value. A method for calendering resin, characterized in that the amount of molten resin supplied to the mill rolls is controlled to maintain a constant amount of molten resin staying on the mill rolls.