JPS5899728A - Measuring apparatus for surface tension of thermoplastic resin - Google Patents

Abstract

PURPOSE:To reliably and accurately measure the surface tension of thermoplastic resins with a simple apparatus, by vertically movably providing a gas extruder, a gas-introducing pipe and a die with a horizontal blow-off surface in a closed vessel which can be heated as well as evacuated. CONSTITUTION:Polyester pellets or other pulverulent and granular bodies are placed in a measuring container 27, which is mounted on a holder 26 of a vessel 1 and hermetically sealed. After a nitrogen replacement, the inside of the vessel 1 is reduced in pressure and maintained under a high vacuum. At the same time, the vessel 1 is heated by a heater 2 to melt the sample. After a predetermined temperature is confirmed by means of a thermometer inserted in a detecting end 19, the vacuum suction is suspended, and nitrogen gas having a predetermined temperature is introduced from a supply nozzle 23. Then, a pinion 17 is rotated to immerse a parallel surface 12 of a die 10 attached to an introducing pipe 9 into the sample in the measuring container 27. Nitrogen is released into the sample by employing an extruder 14 to form a bubble on the parallel surface 12. The size of the bubble is measured through a peep window 6 to measure the surface tension of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention also relates to an apparatus for measuring the surface tension of thermoplastic resins, particularly polyesters.

It is a well-known fact that the surface tension of thermoplastic resins, such as polyester, plays an important role during spinning or molding. However, there is no accurate method for measuring the surface tension of polyester because polyester is difficult to handle due to its high viscosity at high temperatures, and when it comes into contact with moisture or oxygen, it immediately undergoes a decomposition reaction and generates bubbles. I didn't. That is, polyester must be melted at a temperature of about 260° C. to 350° C., and its viscosity is extremely high, ranging from 500 poise to 30,000 poise, making it extremely difficult to simply handle the molten polymer. In addition, in order to overcome high temperature and high viscosity/easy handling, polyester is easily decomposed, that is, hydrolyzed and oxidatively decomposed easily, resulting in deterioration and deterioration of the polyester during handling.

Furthermore, if the polymer is handled under vacuum in order to suppress decomposition, by-products generated by the polymerization reaction, bubbles due to moisture, oxygen, etc. will be generated in the polymer, which will be an obstacle when measuring surface tension, and will actually cause Measurement of surface tension becomes impossible.

In view of such problems, the present inventors have conducted extensive research and have arrived at the present invention.

In other words, the present invention provides a pair of viewing windows facing a sealed container that can be heated and evacuated, which are electrically connected in the horizontal direction, and which are held so as to be movable up and down in a direction perpendicular to the horizontal line connecting the viewing windows. A conduit tube is inserted into the upper part of the container, and a gas extruder is provided at the upper end of the conduit tube, and a gas blowing die having a horizontal blowing surface formed at the lower end is connected to the conduit tube. It is something.

Hereinafter, the present invention will be explained based on the drawings. The figure is a longitudinal sectional view with an embodiment of the invention. In the figure, 1 is a container whose outer surface is coated with an electric heater 2, which includes a main body 11 and an upper lid 1b.
A pair of corresponding nozzles 3 are provided on the side of the main body 1a.
A transparent glass 5 is fixed to the distal end of the transparent glass 5 via a flange 4, and a viewing window 6 is formed by these. There is a packing box 8 at the upper end in the center of the upper lid 1b.
A holding cylinder 7 having a diameter of 10 mm is vertically protruded, and a gas conduction pipe 9 is inserted through the holding cylinder 7 so as to be movable up and down. A packing 8m is inserted into the packing box 8 of the holding cylinder 7, and by pressing the packing presser 8b, the space between the conductive pipe 9 and the container l is sealed and isolated from the outside.

Note that 7a is a fin for heat radiation. Reference numeral 10 denotes a die for forming bubbles which is screwed onto the lower end of the conduit tube 9, and its lower surface forms a horizontal surface 12 having a blowing hole 11 in the center. This horizontal surface should be as smooth as possible, and is usually plated. Furthermore, a fixed frame 13 is provided at the upper end of the conduction pipe 9.
is attached to the pressurizer 14 via the fixed frame 13.
is connected to the conduction pipe 9. Although it is convenient and preferable to use a syringe as the pressurizer 14, it is not limited thereto. Reference numeral 15 denotes a seal stopper made of synthetic rubber at the upper end of the conduit tube 9, into which a hole 9aK is inserted, into which an injection needle 141L is carefully inserted.

Reference numeral 16 denotes a frame fixed to the upper cover 1b, and a pinion 17 is rotatably attached to the upper part of the frame through a bracket 18, and is aligned with a rack 9b carved in the upper part of the conduit 9. The rotation moves the conduit tube 9 up and down, and also serves as a stopper to hold it at a predetermined height. ls and 20 are a temperature detection end and a gas discharge outlet nozzle provided on the top cover, and the outlet nozzle 20 is branched into two parts: a vacuum tube connected to a vacuum source through pipes 21 and 22, and a vent pipe open to the atmosphere. are doing.

23 is a heating fluid supply nozzle provided in the main body 1aK, and a heater 24. Nitrogen gas heated to a predetermined temperature is introduced through the supply pipe 25 and the like. Further, a pedestal 26 is installed at the center inside the main body 1a, and this pedestal 26
6 Measuring container 2 made of transparent glass pasted in a rectangular shape
7 is placed. The measurement container 27 is positioned above the conduction pipe 9.

28 is a support leg.

In addition, the viewing window 6. Conduction pipe 9. The mutual positional relationship of the pedestal 26 and the like may be such that the die 10 is inserted into the measurement container 27 and the die 10 is observed through the viewing window at this time.

In order to measure the surface tension of a thermoplastic resin, for example, polyester, in an apparatus having such a configuration, it is carried out as follows: First, a powder such as polyester pellets or chips is placed in a container 27. , this is a container
After placing the container on a pedestal 26, sealing it, and purging it with nitrogen, the inside of the container 1 is depressurized and maintained at a high vacuum. At the same time, the sample in the measurement container 2 is heated by the electric heater 2 and melted.1 Since the melting is performed under high vacuum (1) (before and after the room), there is less generation of bubbles and no deterioration during melting. It's gone. At this time, the polyester becomes a molten state containing bubbles, but the detection end 19
After confirming the predetermined temperature using a thermometer inserted into the
Nitrogen gas heated to around 0°C is introduced to create a pressure slightly above atmospheric pressure.

By introducing nitrogen, the bubbles in the molten polyester disappear, leaving only the polyester melt in the measuring container 2. After this, bubbles with a constant F9r are formed in the molten polyester, and the size of the bubbles is measured.At this time, the molten polyester does not deteriorate or change in quality, and it is extremely easy to measure because it can be maintained in a state where there are no bubbles. Nitrogen may be introduced by a circulating mass method or may be released into the atmosphere.

In this case, since the conduit tube 9 is located above the measuring container 27, nitrogen enters the hole 9a from the blowout hole 1'1 into the pressurizer 14.
It becomes - to fill the space containing. Next, Binion 17
is rotated to move the conduit tube 9 downward so that the parallel surface 12 of the die 10 is immersed in the molten polyester in the measuring container 27.

After this, nitrogen is released into the polyester using a pressurizer 14 to form air bubbles on the parallel surface 12, and light is applied to the viewing window 6 on the blade side, and a goniometer or cassette meter is used to measure the specifications from the other viewing window 6. The size of the bubbles is measured and the surface tension is calculated from this. In this case, it is preferable to keep the size of the bubbles within a specified range. That is, the bubble diameter is 5 m/m or more, preferably S sa/m to 15'tsy'm.
It is preferable to maintain the bubble height at a constant value of α8 times or less, preferably α8 times to a, 3 times the bubble diameter.

This is thought to be determined by the measurement accuracy of the goniometer and the stability of the bubbles. For bubbles smaller than the above-mentioned size, variations in measurement accuracy have a large effect on the surface tension Q value, while for bubbles that are larger than the above, the bubble size becomes unstable. It is difficult for the bubbles to maintain a constant shape (...For this reason, it is preferable that the horizontal w12 of the die 10 be circular and have a diameter of 15 m 1 m or more, and that the levelness and smoothness be as good as possible.

The above explanation measures the bubble diameter from the outside, so it is suitable for measuring polyester with good transparency.However, it is difficult to apply to polyester that is opaque.
Measurement is performed using an apparatus as shown in Figure 2. That is, in FIG. 2, 30 is a die provided in the conduction tube 9 and has a gas blowing nozzle 31 at the bottom.A conduit 32 for nitrogen supply is connected to the upper end of the conduction tube 9. This conduit 3
A manometer 340 is connected to one side of the manometer 340, and the other side of the i-nometer 34 is connected to a pressure equalizing nozzle 35 provided on the upper lid 1b of the container l via a pressure equalizing pipe 36, so that differential pressure can be measured. It is. Other details are the same as in FIG. In this case, the measurement is the same as above, the melting of polyester,
After defoaming, nitrogen gas is supplied to the conductive pipe 9 through the flow meter 37 and the nozzle 3 is immersed in the molten polyester.
Push out heated nitrogen gas from 1. Then, the pressure at which a bubble is formed in the liquid and the bubble leaves or breaks from the nozzle 31, that is, the maximum oil pressure, is measured with a manometer, and the surface tension is calculated from this value. At this time, the diameter of the nozzle 31 is 50~
It is preferable to set it as SOOμ, and if it is less than 50μ, the differential pressure will be too large and measurement will be difficult, and it will be thicker than SOOβ (this is because the air bubbles will separate from the tip of the nozzle 31 and become loose, causing variations in the measurement data. Further, it is preferable that the outer diameter of the dead end of the nozzle 31 is made small to improve horizontality and smoothness as much as possible.

As described above, according to the present invention, it is possible to reliably, accurately and stably measure the surface tension of a thermoplastic resin, particularly polyester, using a simple device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing another embodiment.

Claims (1)

[Claims] A pair of viewing windows facing a sealed container that can be heated and evacuated are installed in the horizontal direction and are held movable up and down in a direction perpendicular to the horizontal line connecting the viewing windows. A surface tension measuring device for thermoplastic resin, characterized in that a gas extruder is installed at the upper end of the wrinkled conduit, and a gas blowing die is connected to the wrinkled conduit, the gas extruder being provided at the upper end and having a horizontal blowing surface formed at the lower end.