JPH0376612A - Manufacture of synthetic resin sheet and its device - Google Patents

Abstract

PURPOSE:To remove the defect of surface appearance by controlling regularly the bank amount to be formed at the flowing side of molten resin into the gap of glazing rolls so that the ratio of the circumferential speed of the surface of plate like resin to the circumferential speed of the surface of the roll based on an electric signal is held at a preset value. CONSTITUTION:The molten resin having been fusion-extruded from an extruding machine 1 is formed into a platelike shape with a T die 2. The pressure of the molten resin flowing into the gap of glazing rolls 6,6 is changed by the amount of bank 5, and the thickness of the platelike resin at the side of flowing exit is changed. There, the gap of a choke bar is automatically regulated by a choke bar gap-regulator 10, and/or the lip gap of the T die 2 by a lip gap- regulator 11 and/or the revolution number of the glazing roll 6 by a glazing roll revolution number-regulator 12 are automatically regulated similarly by the electric signal from a circumferential speed-control board so that the ratio of the circumferential speed of the surface of the platelike resin wound on the roll to the circumferential speed of the surface of the glazing roll 6 is kept at a preset value. Consequently its appearance defect may be prevented from being generated.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a bank of molten resin that is formed before being rolled with a rolling polishing roll when, for example, an extruder is used to manufacture a synthetic resin board. The present invention relates to a method for manufacturing a synthetic resin plate and an apparatus for controlling the amount of .

[Conventional technology]

For example, in rolling gloss bottom shapes using T dies, in order to maintain good appearance quality of sheet products, it is important to keep the amount of molten resin banks (resin pools) constant. If the amount of bank is not constant,
The manufactured sheet products are defective in terms of appearance.

In other words, if the amount of banks is too large, a wavy pattern will appear on the surface of the sheet product, and if the amount of banks is too small, local depressions will occur on the surface of the sheet product, resulting in poor appearance. Become.

Therefore, in conventional manufacturing, workers manually measure the amount of banks and change the number of rotations of the rolling polishing rolls based on the results, or make the amount of banks uniform in the width direction of the roll. Moreover, in order to keep them constant, it is necessary to change the lip gap of the T die and the choke bar gap, but this work requires a lot of experience and effort, and it is impossible to do it with perfect accuracy. It was possible.

As mentioned above, in order to roll and polish sheet products with good appearance quality, the biggest challenge is how to precisely control the amount of banks to be constant, and moreover, automatically. In the conventional method, the inflow pressure of the molten resin into the rolling polishing roll changes depending on the amount of banks, and the plate thickness changes due to the ballast effect when flowing out from the rolling polishing roll. There is a method of measuring the thickness of a sheet product after it has been formed by a roll, and controlling the number of rotations of the rolling polishing roll, the gap between the lips of the die, the gap between the choke bars, etc. based on the change in the thickness.

[Problem to be solved by the invention]

In the case of the conventional method described above, the key point is to measure the plate thickness, but in the rolling and polishing roll process, since the resin plate is wrapped around the rolling and polishing roll, it is difficult to measure the plate thickness. Therefore, the plate thickness is measured using a plate thickness measuring device after the rolling and polishing process.
After a change in the amount of banks occurs, the minimum time required for the sheet resin to pass through the rolling and polishing roll process is required before the change is detected as a change in sheet thickness, and the result is reflected in the control system. There is a problem in that it is not quick enough to control the bank amount by feeding back to the bank, resulting in poor appearance.

[Means to solve the problem]

In order to solve the above-mentioned problems, the method and apparatus for manufacturing a synthetic resin sheet according to the present invention is such that the synthetic resin is extruded into a sheet shape using a die, and then flowed into a rolling polishing roll to form the sheet. In the method for manufacturing a synthetic resin sheet that performs surface polishing, the peripheral speed of the surface of the rolling polishing roll and the peripheral speed of the surface of the plate-shaped resin wound around the rolling polishing roll are measured, and these peripheral speeds are measured. is converted into an electric signal, and the rolling gloss is adjusted so that the ratio between the circumferential speed of the roll surface and the circumferential speed of the plate-shaped resin surface based on the electric signal is maintained at a preset value. The amount of bank formed on the molten resin inflow side of the rolling polishing roll is controlled to be constant by any one of the rotation speed of the dressing roll, the lip gap of the die, the choke bar gap, or a combination thereof. The apparatus is equipped with measuring means for measuring the circumferential speed of the surface of the rolling polishing roll and the circumferential speed of the surface of the plate-shaped resin wound around the rolling polishing roll, and each of the measured values is a calculation device for calculating the ratio of the circumferential speed of the circumferential speed; The feature is that the regulator is controlled by a speed ratio control panel.

(Function) The present invention was obtained as a result of extensive research into a method for detecting changes in the amount of banks during the rolling polishing process and immediately after bank formation. A method for producing a synthetic resin sheet, in which the surface of the plate-shaped body is polished by being extruded into a shape, and then flowing into a rolling polishing roll to polish the surface of the plate, the method comprising: Measure the circumferential speed of the surface of the plate-shaped resin wound around the application roll, convert these circumferential velocities into electrical signals, and calculate the circumferential speed of the roll and the surface of the plate-shaped resin based on the electrical signal. In order to maintain the ratio of
The amount of banks formed on the inflow side of the molten resin of the roll polishing roll is controlled to be constant by using one or a combination thereof, and as shown in Fig. 4, the roll polishing roll If the radius of is r, the circumferential speed of the roll surface is V, the thickness of the plate-shaped resin wrapped around the rolling polishing roll is d, and the circumferential speed of the surface is V, then the following formula holds true. .

v/V=r/ (d+r) (r=radius of roll (constant)) In other words, the ratio between the circumferential speed V of the surface of the rolling polishing roll and the circumferential speed ■ of the surface of the plate-shaped resin is It depends on the thickness. Therefore, if the ratio of the circumferential speed of the rolling polishing roll mentioned above and the circumferential speed of the surface of the plate-shaped resin is kept constant, the thickness can be kept constant, and as a result, This makes it possible to keep the amount of banks constant.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

Fig. 1 is a flow diagram of the device, Fig. 2 shows the position of the measurement sensor of the circumferential speed measuring device, and Fig. 3 shows the gap between the T die and the choke bar and the measurement of the circumferential speed measuring device arranged in the width direction. The positional relationship in the width direction between the sensor and the choke bar gap adjuster and lip gap adjuster arranged in the width direction of the T die is shown.

In the figure, 1 is a screw type extruder, and the molten resin melted and extruded by the extruder 1 is made into a plate shape by a T die 2, rolled by a rolling gloss roll 6.6°6, and the surface is glossy. The resulting sheet product 13 is then taken up by a tension roll device 14.

3 is a choke bar for adjusting the flow rate of the T-die 2, and 4 is a lip of the T-die 2. Further, 7 is a circumferential speed measuring device, and circumferential speed measuring sensors 7', 7', 7', . . . are disposed in the width direction of the circumferential speed measuring device 7. The circumferential speed of the surface of the plate-shaped resin wound around the rolling roll and the surface of the plate-shaped resin wound around the rolling roll are measured. The number of circumferential speed sensors 7', 7'7', . . . described above is set to 1 for measuring the circumferential speed of the surface of the rolling gloss roll 6 when the width of the plate-shaped resin is 100 mm or less. In addition to one piece, one piece is sufficient for measuring the circumferential speed of the surface of a plate-shaped resin wound around a roll, but if the width of the plate-shaped resin exceeds 100 mm, it is desirable to use two or more pieces.

8 is the circumferential speed measurement sensor 7', 7', 7'...
This is an arithmetic device that calculates the ratio between the circumferential speed of the surface of the rolling glossy roll 6 measured continuously by ... and the circumferential speed of the plate-shaped resin wound around the roll.

Reference numeral 9 denotes a circumferential speed ratio control panel to which an electric signal according to the circumferential speed ratio calculated by the arithmetic device 8 is sent.

10 is a choke bar gap adjuster that adjusts the gap between the choke bars 3 of the T-die 2 in response to an electric signal from the circumferential speed ratio control panel 9; A lip gap adjuster 12 is used to adjust the gap between the lips 4, and 12 is a roll polishing roll rotation speed regulator that adjusts the rotation speed of the roll polishing roll 6 using similar means.

In the circumferential speed ratio control panel 9, the choke bar gap adjuster lO, the lip gap adjuster 11. It is possible to select which one of the rolling polishing roll rotation speed regulators 12 to use for adjustment.

Moreover, the width of the above-mentioned plate-shaped resin exceeds 100 mm, and the circumferential speed measuring sensor 7', ? ',? '...
..., if there are multiple sensors, each circumferential speed measurement sensor 7
', 7', 7', .
',? The lip gap and/or the choke bar gap at the positions corresponding to the positions of ', . . . are adjusted.

To further explain a specific example of circumferential speed measurement, the measuring device is an optical unit MODEL630 manufactured by Minato Electronics ■.
In other words, a backscattering type differential Doppler non-contact type measurement sensor employing a He-Ne laser was used.

The present embodiment is constructed as described above, and the molten resin melted and extruded by the screw extruder 1 is extruded into a plate shape by the T die 2, and is polished by the rolling polishing roll 6.6. and becomes a sheet product 13 and a tension roll device 14
It will be picked up at

A bank (resin pool) 5 is formed on the inflow side of the molten resin of the rolling polishing roll 6.6, and depending on the amount of the bank 5, the rolling polishing roll 6.6
The pressure of the molten resin flowing into the rolling polishing roll 6 changes, and the thickness of the resin plate on the outflow side changes due to the ballast effect. The circumferential speed of the surface of the resin is measured by the measurement sensor 7' of the circumferential speed measuring device 7, the arithmetic unit 8 calculates the ratio of the circumferential speeds, and an electric signal according to the ratio is sent to the circumferential speed ratio control panel. 9
sent to.

A peripheral speed ratio control panel 9 is operated so that the ratio between the peripheral speed of the surface of the polishing roll 6 and the peripheral speed of the surface of the plate-shaped resin wound around the roll is maintained at a preset value. The electric signal from the choke bar gap adjuster IO determines the gap between the choke bars, or the lip gap adjuster 11 determines the lip gap of the T die 2, and/or the rolling polishing roll rotation speed adjuster I2 determines the rotation speed of the rolling polishing roll 6. will be automatically adjusted.

In addition, if a plurality of circumferential speed measurement sensors 7', 7', ..., which measure the circumferential speed of the surface of the plate-shaped resin are disposed, each of the circumferential speeds of the surface of the polishing roll 6 may be so that the circumferential speed ratio of is maintained at the preset setting circumferential speed ratio,
A choke bar gap adjuster 10 arranged at a position corresponding to each peripheral speed measuring sensor 7'7', .
10. ...and/or lip gap adjuster 11.1
1. ...The gap between the choke bars 3 and/or the gap between the lips 4 is automatically adjusted.

As explained above, if the ratio between the circumferential speed of the surface of the rolling polishing roll and the circumferential speed of the surface of the plate-shaped resin wound around the roll can be kept constant at a preset ratio,
The amount of banks 5 formed on the molten resin inflow side of the rolling polishing roll 6 can be adjusted to a constant value in the width direction, and therefore the appearance of the sheet product 13 can be improved.

〔Effect of the invention〕

According to the method and apparatus for producing a synthetic resin sheet according to the present invention, it is possible to uniformly adjust the amount of banks formed on the inflow side of the molten resin of the rolling polishing roll to a constant value in the middle direction. The surface appearance of the sheet product is of excellent quality with no defects.

[Brief explanation of drawings]

1 to 3 of the drawings show embodiments of the present invention.
The figure is a flowchart of the device, Figure 2 is an explanatory diagram of the arrangement of the measuring sensor of the circumferential speed measuring device, and Figure 3 is the choke bar gap adjuster and lip gap adjuster arranged in the width direction of the T die. An explanatory diagram of the positional relationship with the measurement sensor arranged in the width direction for circumferential speed measurement. Figure 4 is an explanatory diagram of the state in which plate-shaped resin is wrapped around the rolling polishing roll, and Figure 4 (a) is the side view. figure,(
B) is a sectional view. 1. Extruder complete with varnish 2: T die 3: Chalk bar of T die 4: Lip of T die 5: Bank 6.6: Rolling and polishing roll 7: Peripheral speed measuring device 7', 7',...・: Peripheral speed measurement sensor 8: 9: 10: 11: 12: Arithmetic device Peripheral speed ratio control panel Choke bar gap adjuster Lip gap adjuster Rolling polishing roll rotation adjuster

Claims (2)

[Claims] (1) In a method for producing a synthetic resin sheet in which the surface of the sheet is polished by extruding the synthetic resin into a sheet using a die and then flowing into a rolling polishing roll, the periphery of the surface of the rolling polishing roll is The circumferential speed of the surface of the plate-shaped resin wound around the rolling polishing roll is measured, these circumferential velocities are converted into electric signals, and the circumferential speed of the roll surface and the plate-shaped resin surface are determined based on the electric signals. The rotational speed of the rolling polishing roll, the lip gap of the die,
A method for producing a synthetic resin sheet, characterized in that the amount of banks formed on the molten resin inflow side of a rolling polishing roll is controlled to a constant level by any one of the choke bar gaps or a combination thereof. . (2) Provide a measuring means for measuring the circumferential speed of the surface of the rolling polishing roll and the surface circumferential speed of the plate-shaped resin wound around the rolling polishing roll, and calculate the ratio of each of the measured peripheral speeds. and a circumferential speed ratio control board comprising at least one of a choke bar gap adjuster, a die lip gap adjuster, and a rolling polishing roll rotation speed adjuster, and a peripheral speed ratio control board that controls the adjustment by the circumferential speed ratio control board. A synthetic resin sheet manufacturing device characterized by controlling a container.