JPS61126448A - Detection of foreign matter in polymer - Google Patents

Abstract

PURPOSE:To improve measuring accuracy and to simplify the measurement by irradiating laser light of a light emission wavelength in a UV range to a polymer, detecting the fluorescence intensity of part of the scattered light and detecting the gel and the size and number of other foreign matter. CONSTITUTION:For example, an He-cd laser light source 1 having the wavelength in the UV region, a condenser lens 8, a fluorescent filter 9 and a photoelectric multiplier 10 are provided to a grain size meter having a condenser lens 3, a stationary filter 4, a rotary filter 5, a condenser lens 6 and a photoelectric multiplier 7. The laser light of the wavelength (about 440m) of the UV region is irradiated from the light source 1 to a sample 2, then the foreign matter emits fluorescence if said matter is the gel. The presence or absence of such fluorescence is detected by the photoelectric multiplier 10 by which the gel is discriminated from the other foreign matter. The number and grain size of the foreign matter and gel in the polymer are thus easily measured with good accuracy.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention detects the size and number of foreign substances, especially gel-like foreign substances, in polymers in a molten state, dissolved state, film form, fiber form, etc. Regarding the method.

(Prior art) Foreign matter mixed into the polymer, that is, inorganic foreign matter such as catalytic foreign matter, organic foreign matter such as highly crystallized polymer, and gelled products generated from polymer deterioration products have a large impact on the molding process. .

To explain this using the manufacturing process of polyester yarn as an example, in a single spun product, foreign matter and/or organic foreign matter in the polymer are captured by the polymer filtration layer in the spinning bag, so the bag becomes clogged due to clogging of the filtration layer. Pressure increases. and,
If the puncture pressure rises too much, the foreign matter trapped in the bag filtration layer will flow out and cause yarn breakage and single fiber breakage during the drawing process, so when the bag pressure rises to a certain level, the bag must be replaced. This prevents trapped foreign matter from flowing out. For this reason, in polymers containing inorganic and organic foreign substances, bag replacement occurs frequently, which greatly reduces productivity.

In addition, gelled products generated from degraded polymers are difficult to be captured by the filtration layer in the spinning bag, or even if they are captured, they easily flow out, so they get mixed into the spun yarn and cause frequent breakage of single fibers during the drawing process. , the resulting drawn yarn has extremely low commercial value.

Furthermore, when molding into a polyester film, foreign matter in the polymer creates protrusions on the film surface, causing so-called dropouts in video tapes.

In this way, there are very few measurement methods that can accurately and easily detect foreign substances in polymers to provide various hidden images.
is.

Conventionally, in order to measure the amount of foreign matter in this delicate polymer, a spinning model plant was created, and several kilograms to several tens of kilograms of polymer were passed through a spinning bank with a fine-mesh filter inserted. In addition to measuring the pressure rise, a method is used in which foreign substances captured by the filter are observed using a microscope or the like after dissolving the polymer.

However, this method requires a considerable amount of polymer, and also requires time for pretreatment such as polymer drying, filter disassembly, and determining the type of foreign matter on the filter.
Moreover, there are drawbacks such as the need for skill on the part of the measurer.

(Object and structure of the invention) The present invention has been made against the background of the above circumstances,
The purpose is to provide a method for accurately and easily measuring the number and particle size of foreign substances and gels in a polymer.

The inventors of the present invention conducted studies to achieve this objective, and found that when a solution obtained by dissolving a polymer in a solvent or a thin film obtained by molding a polymer is irradiated with ultraviolet rays, if the foreign matter is a gel, it will fluoresce. Laser He
-It was discovered that by using a Cd laser whose wavelength is in the ultraviolet region and detecting the fluorescence intensity of a part of the scattered light, it is possible to detect the quantity and size of all foreign substances and to discriminate gel foreign substances from among them. This led to the invention. In other words, the present invention irradiates particles with laser light and determines the size and number of particles using the interference fringes of the scattered light. 1] In the method of detecting foreign substances in a polymer using a granulometer, the laser beam of the granulometer is used to irradiate a polymer with an emission wavelength in the ultraviolet region, and a portion of the scattered light is detected with a fluorescence intensity of 1 dJi''. This is a method for detecting foreign substances in polymers, which is characterized by separately detecting the thickness and number of gel and other foreign substances.

Hereinafter, the present invention will be explained based on the drawings. Figure 1 is a schematic perspective view of an apparatus for carrying out the present invention.

In the figure, 1 is a laser beam, and a beam expander (not shown) is used to make the light beam to an appropriate size, and then irradiates it onto a sample cell 2, which is made of a glass tube through which particles diluted with water, etc. are flowed. be done.

If there are particles in sample 2, the laser light will be scattered, but
After the scattered light is turned into parallel light by a condensing lens 3 provided at the rear, a fixed filter 4 having a slit opening provided at the focal point of the condensing lens 3 and a plurality of (for example, 13) windows 5a are used. The light passes through the rotating filter 5 having a 9-axis beam, and is focused by the condensing lens 6 provided on the KQ side onto the photomultiplier tube 7 at the rear, regardless of which window 5a of the rotating filter 5 the light passes through. ing. The above is a conventional particle size meter (
For example, the product name M manufactured by Lead@& Northrup
ierotrac), and the scattered light of foreign particles creates interference fringes (ring-shaped) on the fixed filter 4, but the fixed filter 4 has a slit hole 41 that cuts out the interference fringes in a certain radial direction from the center. pass the statue.

The light that has passed through the fixed filter 4 reaches the rotating filter 5, but the rotating filter 5 has a plurality of windows (13) at equal angles, and the distance from the center increases by equal steps. In addition, although not shown, a rotational position detection device is provided on the rotational shaft so that it can be determined which window 5a of the rotary filter 5 is located behind the slit 4a, and it is possible to detect particles. The diameter of the interference fringes, which changes depending on the particle diameter, is determined by rotating the rotary filter 5 and determining the change in the amount of light that sequentially passes through several windows 5a.

The present invention improves the conventional particle size meter by measuring 6 (6) of foreign substances in polymers.
1j constant, which has been improved to distinguish foreign matter into gel and other foreign matter for measurement; for example, laser light source 1)
A re-Cd laser (wavelength: approx. 44 (1+m)) with a wavelength in the ultraviolet region is selected, and another condenser lens 8 is installed at a different angle from the condenser lens 3 to collect scattered light. After condensing a part of the light and passing it through a fluorescence filter 9, it is detected by a photomultiplier tube 10.The total number and size of foreign particles can be determined from the output of the photomultiplier tube 7. Since the foreign matter emits fluorescence only when it is a gel, the presence or absence of this fluorescence can be detected by the photomultiplier tube 10 and the gel foreign matter can be distinguished from other foreign matter.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example [η) = 0.6, titanium oxide content (1.3wt
% polyethylene terephthalate (hereinafter referred to as PET) chips were melted and made into a mesh with a mesh size of 2000.
F in the filtration device (eggplant with a filter built into the bag)
After this, the filter installed in the bag was taken out and the polymer component was dissolved with O-chlorophenyl to separate the foreign matter captured by the filter, and the total amount of foreign matter was measured.

Furthermore, the amount of gelled material was measured by irradiating the separated foreign matter with ultraviolet rays and observing the fluorescence generated with the naked eye.

Next, PET5Ii, which was the same as the polymer filtered using the eggplant filtration device, was heated in 50 ml of O-ri pp phenol to completely dissolve the sample, and the amount of foreign matter was determined using the device shown in FIG.

The light source is "C", the output is 10 mW, and the wavelength is 441.6 n.
A He-Cd laser beam (light diameter u, 3 mys) was used. A sample was passed through a cylindrical glass cell with a diameter of 500 μm, and the scattered light was detected by a photosensor 7 and quantified using a commercially available Microtrack viscosity analyzer [K]. At the same time, the cut wavelength of the colored glass filter 9 was set to 470 nm in order to catch only the fluorescence generated when the foreign matter was gel.

This generates reflection light that is detected by the sensor 10 and interrupts the analysis system of the Microtrac viscosity needle mentioned above to separate out the gel foreign matter and remove the glint 7.
Ta.

The total amount of foreign matter and the amount of gelled material thus obtained were approximately the same as the amount of gelatinized material obtained using the Nastro filter device.

(Effects of the Invention) According to the present invention, it is not only possible to detect the number of foreign particles with high precision, but also to distinguish gel foreign substances formed from degraded polymers, etc., and to identify the source of the foreign particles. It has a huge effect on the above.

4. 1w of the drawing! FIG. 1 is a schematic perspective view of an apparatus for carrying out the present invention.

1... Laser, 2... Sandal cell, 3...
・Condensing lens, 4...Identification filter, 5...
Rotating filter, 6, 8... condensing lens.

7, 1O...Photomultiplier tube, 9...Fluorescence filter patent 1 lease Teijin Ltd.

Claims (1)

[Claims] In the method of detecting foreign substances in polymers using a granulometer, which irradiates particles with laser light and measures the size and number of particles based on the interference fringes of the scattered light, the laser of the granulometer is used to irradiate the polymer with an emission wavelength in the ultraviolet region. irradiate light,
A method for detecting foreign matter in a polymer, comprising separately detecting the size and number of gel and other foreign matter by detecting the fluorescence intensity of a part of the scattered light.