JPH0465222A - Apparatus for in-line measurement of degree of orientation of film/sheet - Google Patents

Abstract

PURPOSE:To perform the optimizing control of a molding condition, the quality control of a product, the foreknowledge of breakage and the detection of foreign matter by monitoring a degree of orientation by allowing a film/sheet to run between polarizers to measure the quantity of double refraction of the film/sheet according to an in-line system. CONSTITUTION:The resin molten by an extruder 1 is extruded from an automatic die 2 to become a sheet-like state and the extrudate is cooled and solidified by a casting machine 3 to be molded into a raw sheet. The raw sheet is biaxially stretched in both of a line direction and a film lateral direction in succession by longitudinal and lateral stretching machines 4, 6 to be taken up by a taking-up winder 8. Herein, degree-of-orientation meters 5, 7 are operated in the film lateral directions to respectively measure the degrees of orientation of the film after longitudinal stretching and lateral stretching and a stretching condition is controlled by a main control apparatus 11.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is an in-line measurement of the degree of orientation of films and sheets that can be used in film and sheet manufacturing equipment such as sheet manufacturing equipment, non-stretched film manufacturing equipment, and two-wheel stretched film manufacturing equipment. It is related to the device.

(Prior technology) Conventionally, there has been no in-line measurement of the degree of orientation of films and sheets, and product evaluations have been performed by measuring molded samples using chi-ray diffraction, polarized fluorescence, birefringence, etc. Ta.

(Problem to be solved by the invention) Conventionally, the degree of orientation of films and sheets, which is an important factor in product evaluation, was measured off-line from samples after molding.
Although we have tried to optimize the forming conditions, etc., in particular in the process of stretching films and sheets, if a uniform degree of orientation cannot be obtained due to the stretching conditions, or if stress concentration occurs due to foreign matter, etc., the product may break. Since there were problems such as "in-line measurement", there was a demand for in-line measurement.

The present invention provides an in-line measurement device that measures the degree of orientation or stress state of a film in-line, and aims to solve the above-mentioned conventional problems.

(Means for Solving the Problems) For this reason, the present invention provides a film/sheet manufacturing apparatus in which orthogonal polarizers are provided on the film/sheet manufacturing line, and the film/sheet is run between the polarizers. The amount of birefringence of the sheet is measured in-line, the degree of orientation is monitored, and the molding conditions are controlled.
This is a means to solve problems.

(Function) A film/sheet is run between orthogonal polarizers, and the spot-shaped orthogonal polarizer is operated in the width direction of the film/sheet to measure the amount of birefringence in the width direction. A polarizer is provided and the amount of birefringence is measured in-line at the same time.

(Example) The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a biaxially stretched film manufacturing apparatus.

In the figure, the resin melted by an extruder 1 is extruded from an automatic die 2 to form a sheet, and then the resin is melted by an extruder 1.
The material is cooled and solidified to form a raw sheet. The raw sheet is sequentially stretched in two wheels in the line direction (MD force direction) in the longitudinal stretching machine 4 and in the film width direction (TD force direction) in the transverse stretching machine 6, and then wound up in the take-up winder 8.

In this example, the orientation needles 5 and 7 are arranged in the film width direction (T
The film is operated in the D force direction to measure the degree of orientation in the width direction of the film after longitudinal stretching and transverse stretching, respectively, and the main controller 11 controls the stretching conditions.

In the above examples, the orientation needle was provided after the film was stretched, but the orientation needle was provided in the stretching section to monitor the stress state during stretching to control the stretching conditions and predict breakage.
It is also possible to perform foreign object detection. Further, in the above embodiments, the present invention was applied to a two-wheel stretched film manufacturing apparatus, but it is also applicable to measuring the degree of orientation of films and sheets in sheet manufacturing apparatuses, non-stretched film manufacturing apparatuses, and the like.

FIG. 2 shows details of the orientation needle. The parallel light rays emitted from the spot light source 12 are converted into plane polarized light by a polarizer 13 and an analyzer 17 which are orthogonal to each other, and are then converted into plane polarized light by a two-wavelength plate 14.16.
The light is circularly polarized. As shown in the figure, the polarization axis is made to coincide with the film line direction (MD force direction) and the film width direction (TD force direction).In this way, using the optical system, the light after passing through the film 22 is directed to the image receiving device f18. The degree of orientation is measured from the amount of birefringence.

Fig. 2 shows a method of operating the orientation needle in the film width direction using a spot light source, but as shown in Fig. 3, the amount of birefringence in the film width direction is simultaneously measured using a line light source 19. It is also possible to do so. Note that, similar to FIG. 2, the parallel light rays emitted from the line light source 19 are
The polarizer 20 and the analyzer 24 that are perpendicular to each other make it plane polarized light, and the A wavelength plate 2L23 makes it circularly polarized light.

Also, as shown in the figure, the polarization axis is in the film line direction (
MD force direction and film width direction (match with TD force direction).

(Effects of the Invention) Since the orientation degree inline measuring device of the present invention is configured as described above in detail, it measures the amount of birefringence of a film/sheet inline, monitors the orientation degree, and optimizes molding conditions. Control, product quality control, fracture prediction, foreign object detection, etc. are possible.

[Brief explanation of drawings]

FIG. 1 is a plan view of a biaxially stretched film manufacturing apparatus to which an in-line film/sheet orientation measuring device according to an embodiment of the present invention is applied, and FIG. 2 is a spot-shaped orientation needle showing an embodiment of the present invention. FIG. 3 is a perspective view of a line-shaped orientation needle showing an embodiment of the present invention. Description of main parts of diagram

Claims (1)

[Claims] In film/sheet manufacturing equipment, orthogonal polarizers are installed on the film/sheet production line, and the film/sheet is run between the polarizers to measure the amount of birefringence of the film/sheet in-line and monitor the degree of orientation. An in-line measuring device for the degree of orientation of films and sheets, which is characterized by controlling molding conditions, etc.