JPH0641905B2 - Capillary viscometer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a capillary viscometer used for measuring the viscosity of thermoplastic resins and the like.

[Prior Art] As a viscometer used for measuring the viscosity of thermoplastic resins,
It is a capillary viscometer in which a molten sample filled in a cylinder is pushed out by a piston through a nozzle hole of a die, and the viscosity of the sample is obtained from the outflow speed.

With this type of capillary viscometer, the sample in the cylinder is heated and melted during preheating (usually at the midpoint of the set preheating time).
In the above, the pressure is forcibly applied by the piston to remove the air remaining between the samples.

[Problems to be Solved by the Invention] When air is vented by forcibly applying pressure as described above, the air existing between the samples is exhausted through the die hole or the gap between the cylinder and the piston. However, there was a problem that the measurement data varied and the measurement could not be performed accurately because some of the data did not come out and remained in the sample.

[Means for Solving the Problems] The present invention adopts the following configurations in order to solve the above problems.

That is, the thin tube viscometer according to the present invention is a thin tube type viscometer in which a molten sample in a cylinder is pressed by a piston to flow out from a nozzle hole of a die provided on the cylinder outlet side, and the viscosity of the sample is measured from the outflow speed. In the viscometer, a connecting jig that connects the nozzle opening of the die and the suction opening of the vacuum pump is detachably provided.

[Operation] After the sample is put into the cylinder, the nozzle port of the die and the suction port of the vacuum pump are connected by a connecting jig, and if the vacuum pump is used to evacuate the cylinder, the air remaining between the samples is completely removed. Can be exhausted.

[Embodiment] FIG. 1 shows an embodiment of the present invention. This capillary viscometer 1 has a cylinder 3 having a hole 2 as a sample chamber in its core, and a cylinder 3 accommodated in the sample chamber. A piston 6 for pressurizing the sample 5 and a die 8 provided in close contact with the outlet side of the cylinder are provided. The die 8 is fitted in the concave receiving portion 9a of the cylindrical die pressing metal fitting 9 and is held by the die pressing member. It is supported by metal fittings. A heater 10 is provided on the outer peripheral portion of the sample chamber of the cylinder 3.
Is wound.

The die pressing metal fitting 9 has a screw portion 9b provided on the outer peripheral portion thereof.
Is attached to the cylinder 3 by being screwed onto a screw portion 3b provided on the lower side of the cylinder 3. Further, a through hole 11 communicating with the hole 8a of the die is formed in the core portion of the die pressing metal fitting 9, and a vacuum suction metal fitting fitted into the concave receiving portion 9c of the pressing metal fitting in which the through hole 11 is formed. 13 are provided. A through hole 14 is formed in the core of the vacuum suction fitting 13 so as to match the opening of the through hole 11, and the fitting 1
3 has a projection 13a formed at the rear end thereof.
Reference numeral 4 denotes a projecting portion 13a which is a pore and is open to the outer peripheral portion.

A hose 16 is attached to the protrusion 13 a of the vacuum suction fitting 13. The other end of the hose 16 has a vacuum pump 17
It is attached to the suction port of. An opening / closing cock 18 is provided in the middle of the hose 16.

When a test is performed using this thin tube viscometer 1, the sample 5 is first accommodated in the cylinder 3 and the piston 6 is inserted into the sample chamber. The vacuum pump 17 is driven by fitting it so as to match the through hole 11 of 9. Since the suction port of the vacuum pump 17 communicates with the nozzle hole 8a of the die through the through holes 14 and 11 by the hose 16, the air existing between the samples accommodated in the sample chamber is discharged from the nozzle hole 8a of the die. Exhausted.
At this time, since the vacuum suction fitting 13 is closely attached to the die pressing fitting 9 against its own weight due to the exhaust of the inside of the cylinder, the fitting state is maintained without requiring a special fitting fitting. can do.

When the sample is heated by energizing the heater 10 and the midpoint of the set preheating time at which the sample is almost melted is reached, the vacuum suction fitting 13
To remove and finish the exhaust work. To attach and detach the vacuum suction fitting 13, open the opening / closing cock 18 provided in the middle of the hose 16, introduce a little air into the hose, and release the fitting state of the vacuum suction fitting 13 and the die pressing fitting 9 by the vacuum force. It is easily performed by the weight of the metal fitting 13 itself.

After exhausting the air remaining between the samples in this way,
The sample 5 is pressurized by the piston 6 inserted in the cylinder 3, and the viscosity of the sample is obtained by measuring the outflow rate of the sample flowing out from the nozzle hole 8a of the die 8.

In the above example, for the sample contained in the sample chamber of the cylinder, the air remaining in the sample is exhausted to the vacuum pump side by pulling the sample chamber to a vacuum at the time of melting in the preheating stage. The outflow is performed evenly. Therefore,
Since there is no variation in the viscosity measurement data, the viscosity can be measured accurately. In addition, as described above, the vacuum suction fitting itself adheres to the die holding fitting by drawing a vacuum inside the sample chamber, and after evacuation, it can be easily detached by simply adding a little air to the vacuum communication passage, connecting both. There is no need for a separate mounting tool.

When the vacuum suction fitting 13 and the die pressing fitting 9 are in close contact,
As shown in FIG. 2, in order to prevent air leakage from the contact surface and lower exhaust efficiency, the vacuum suction fitting 1
The O-ring 20 may be fitted into the contact surface portion at the tip of the three.

[Effects of the Invention] As is clear from the above description, according to the capillary viscometer of the present invention, the air remaining in the sample is completely exhausted during the preheating and melting of the sample before the start of the test. There is no variation in the data of the outflow rate measurement, and it is possible to measure the viscosity accurately.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. FIG. 2 is a view showing a modified embodiment of the essential part. 2 ... Sample chamber, 3 ... Cylinder, 5 ... Sample, 6 ... Piston, 8 ... Die, 9 ... Die pressing fitting, 13 ... Vacuum suction fitting, 16 ... Hose, 17 ... Vacuum pump

Claims (1)

[Claims] 1. A capillary viscometer which presses a molten sample in a cylinder with a piston to cause it to flow out from a nozzle hole of a die provided on the cylinder outlet side, and measures the viscosity of the sample from the outflow speed of the die. A capillary viscometer characterized in that a connecting jig that connects the nozzle port and the suction port of the vacuum pump is detachably provided.