JP3214732B2 - Method and apparatus for measuring viscosity while stirring liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the viscosity of a liquid while stirring the liquid, and more particularly, to the change of a liquid such as printing ink as it passes through each printing unit of a printing press. For example, the present invention relates to a method and a device capable of directly measuring the viscosity of a liquid at the time of dispersion and emulsification by stirring while reproducing the same.

[0002]

2. Description of the Related Art Conventionally, various viscosity measuring devices have been proposed, and a rotational viscometer is known as one of them. This rotational viscometer utilizes the fact that when an object such as a cylinder, a disk, or a sphere is rotated in a fluid, the object receives torque due to the viscous resistance of the fluid. It is also used to determine the flow curve of

However, it is mainly the shear viscosity that can be directly measured by this rotational viscometer. Among the liquids, for example, when the printing ink passes through each printing unit of the printing machine, it acts on the dampening solution to cause the printing ink to print. Is dispersed or emulsified, and in the actual printing operation, although the viscosity at the time of dispersion and emulsification is an important factor, water separation occurs at the time of measurement with the conventional rotational viscometer. It was difficult to determine the viscosity accurately.

That is, a lithographic printing ink forms a resin base having the same degree of viscosity as a varnish, and this base is used.
And kneaded with pigments in a vehicle. In the printing process, this printing ink acts on the fountain solution of lithographic and offset printing, causing dispersion and emulsification. Above all, if the viscosity is reduced by this dispersion and emulsification, the degree of transfer of the printing ink becomes worse. And printed matter with good ink film cannot be obtained.

[0005] By the way, with a conventional rotational viscometer,
When measuring the viscosity of the dispersed and emulsified printing ink, the printing ink sample is dispersed and emulsified by a stirrer,
This is sampled and measured by a rotational viscometer.

[0006]

However, in the case of measuring as described above, when the dispersion and emulsification are sampled and measured by a conventional rotational viscometer,
Since the measurement is performed while sampling the sample one by one, it takes a long time for the measurement, and it is impossible to measure continuously.

An object of the present invention is to solve the above-mentioned drawbacks. Specifically, a liquid capable of continuously measuring, for example, the viscosity of a liquid under stirring while simultaneously stirring, for example, dispersing and emulsifying a liquid such as printing ink. We propose a method and an apparatus for measuring the viscosity of.

[0008]

In order to achieve this object, a method according to the present invention comprises forming a narrow portion in a part of an annular space formed between rotating inner and outer cylinders, and measuring the annular space in the annular space. After putting the liquid to be added, rotate the inner and outer cylinders at different speeds, while stirring the liquid in the narrow part of the annular space,
At this time, any torque or rotational driving force of the inner and outer cylinders is measured, and the viscosity of the fluid is detected from the measured value.

An apparatus best suited for carrying out this method has a basic structure of a double cylindrical structure shown in FIG. That is, in FIG. 1, reference numeral 1 denotes an inner cylinder, 2 denotes an outer cylinder, and these inner and outer cylinders 1 and 2 are both rotatable,
In the cylindrical outer cylinder 2, a cylindrical inner cylinder 1 is provided with a speed difference.
To store. The rotation axis of the inner cylinder 1 is not coaxially arranged with the rotation axis of the outer cylinder 2, but is spaced apart in parallel and arranged. Further, the separation interval is configured to be controlled or adjusted, and furthermore, the inner cylinder 1 and the outer cylinder 2 are configured to be rotatable by independent speed control mechanisms.
The speed difference between the inner and outer cylinders 1 and 2 is normally provided in the same direction of rotation, but may be provided in a different direction of rotation or only one of the rotations as necessary.

A spiral groove is provided on the outer surface of the inner cylinder 1 in a direction in which a downward force acts during rotation, for example, by grooving. Even a viscoelastic fluid that is easy to measure can be easily measured.

Further, in order to quantitatively supply the liquid to the annular space between the inner and outer cylinders 1 and 2, a liquid supply device is provided so that the viscosity can be continuously measured while changing the mixing ratio of the liquid. I do.

[0012]

In the present invention, as described above, since the inner cylinder 1 and the outer cylinder 2 rotate at a predetermined speed difference, the torque due to the viscosity of the liquid acts on the inner cylinder 1 acting as a liquid stirring section. I do. The rotation axis of the inner cylinder 1 and the rotation axis of the outer cylinder 2 are not coaxial but parallel and eccentric. Further, a narrow portion 13 is formed in at least a part of the annular recess 13 formed between the inner and outer cylinders.
Since a is formed, a high shear is given to the liquid passing through the narrow portion 13a, whereby the stirring of the sample can be effectively performed.

That is, in the present invention, first, the viscosity is measured while performing operations such as emulsification of a liquid sample. At this time, since the rotation axis of the inner cylinder 1 is eccentric with respect to the rotation axis of the outer cylinder 2 to form a narrow portion, the stirring efficiency of the liquid sample is increased,
The liquid sample is well agitated. More specifically,
After the liquid sample flows into and passes through the narrow portion 13a, the liquid sample is stretched between the inner and outer cylinder surfaces, and the measured torque is influenced by the extensional viscosity in addition to the shear viscosity. . This state is equivalent to a state in which the printing ink is stretched after passing through the nip between the rolls (the contact portion between the rolls) in an actual printing unit. It can be measured by passing through the narrow portion 13a. Further, since there is a difference in rotation speed between the inner and outer cylinders 1 and 2, the effect of extending (extending) the sample is amplified.

Further, since all liquid samples pass through the narrow portion 13a where high shear is generated without causing stagnation, the stirring becomes uniform. At this time, the torque generated on the surface of the inner cylinder 1 is measured. The viscosity change of the liquid sample can be continuously measured.

The maximum shear rate applied to the liquid sample at the narrow portion 13a where the distance between the inner and outer cylinders 1 and 2 is the smallest as described above depends on the distance between the narrow portion 13a, the rotation speed of the inner and outer cylinders 1 and 2, or It can be easily controlled by adjusting the speed difference.

By the way, when the shear speed Dm in the narrow portion 13a rotates in the same direction, the distance between the outer surface of the inner tube 1 and the inner surface of the outer tube 2 (the distance of the narrow portion 13a) is C (see FIG. 1). Assuming that the linear velocity on the outer surface of the inner cylinder 1 is Vi and the linear velocity on the inner surface of the outer cylinder 2 is Vo, the linear velocity can be expressed by the following equation. Dm = (Vi−Vo) / C Accordingly, if the distance of the narrow portion 13a and the speed difference between the inner and outer cylinders are determined in advance, the values are determined in such a manner that the maximum shear rate applied to the liquid sample is defined. Measurement becomes possible.

[0017]

Next, the present invention will be described in more detail with reference to the illustrated embodiments.

FIG. 1 is an explanatory view showing the principle of the present invention in cross section, FIG. 2 is a front view of an example of an apparatus for carrying out the present invention, and FIG. 3 is a side view of the apparatus shown in FIG. Yes, FIG. 4
FIG. 5 is an explanatory view showing a part of a device according to another embodiment of the present invention, FIG. 5 is a graph showing a relationship between torque acting on an inner cylinder and viscosity, and FIG. 6 is a graph showing a relationship between water content and torque. 7 is a graph showing the relationship between the stirring time and the torque, FIG. 8 is a graph showing the relationship between the water content and the torque ratio, and FIG. 9 is a graph showing the relationship between the size of the narrow portion (mm) and 4 is a graph showing the required shear rate (1 / sec).

First, in FIG. 2, the inner cylinder 1 is indicated by a dotted line, and the inner cylinder 1 is connected to a driving motor 5 via a bearing 3 and a torque detector 4. It is preferable that the driving motor 5 can be controlled so that the rotation speed of the inner cylinder 1 is in the range of 40 to 4000 rpm. The bearing 3, the torque detecting unit 4 and the driving motor 5 are mounted on a pedestal 6, and the pedestal 6 is configured to be movable in a vertical direction, and the pedestal 6 is moved up and down by a motor 7.

The outer cylinder 2 is configured to be rotatable at, for example, 0.1 to 120 rpm by an outer cylinder driving motor 9 around the outer cylinder 2. Although the rotation direction of the inner cylinder 1 can be configured in only one direction, the rotation direction of the outer cylinder 2 is configured to be able to select either the same direction as the inner cylinder 1 or the opposite direction.

A thermostatic bath 8 is provided around the outer cylinder 2 through which a heat medium can circulate, so that temperature control is possible. The outer cylinder 2, the thermostat 8 and the motor 9 for driving the outer cylinder are mounted on a pedestal 10 which can be moved horizontally, and the position can be adjusted by a feed screw 11.

With this configuration, the pedestal 10 is mounted on the inner cylinder 1.
The position can be adjusted in a range from a position where the rotation axis of the outer cylinder 2 coincides with the rotation axis of the outer cylinder 2 to a position where the inner cylinder and the outer cylinder are in contact with each other, and thus the distance of the narrow portion 13a can be adjusted.

The torque received by the inner cylinder 1 due to the viscosity of the liquid sample to be measured is detected by the torque detector 4 connected to the inner cylinder 1, but it is not always necessary to detect the torque by the torque detector 4. , Motor 5 for driving inner cylinder 1
The torque can be detected by measuring the electric power of the motor. The inner and outer cylinders 1 and 2 can be configured in any dimensions as desired, but usually the outer cylinder 2 has a diameter Do of 30 mm, the inner cylinder 1 has a diameter Di of 20 mm, and the inner cylinder has a immersion length L of 60 mm.
It is preferable to set the degree.

Further, it is preferable that the narrow portion 13a formed between the inner and outer cylinders 1 and 2 is about 0.1 to 2.0 mm. That is, the narrow portion 13a gives a predetermined stirring to the liquid sample to be measured as described above. Therefore, the narrow portion 13
If the size of a is too large, the stirring efficiency decreases,
For example, emulsification close to that of the printing ink in the printing unit cannot be obtained. On the other hand, if the size of the narrow portion 13a becomes too small and becomes less than 0.1 mm, unless the working accuracy of the inner and outer cylinders 1 and 2 is considerably increased, the size of the narrow portion 13a is affected by runout during rotation. Are non-uniform, causing an error.

By the way, the inner cylinder is 2,000 rpm,
The outer cylinder was rotated at 60 rpm, and the relationship between the size of the narrow portion and the shear rate of the liquid sample was determined.

A spiral groove 1a can be formed on the surface of the inner cylinder 1 as shown in FIG. This groove 1
a is formed in a direction in which the liquid sample is pushed downward during rotation, and the depth, width, pitch and the like are determined according to the properties of the liquid sample to be measured. A width of 5 mm, a width of 3 mm, and a pitch of 5 mm is sufficient. Furthermore, depending on the liquid sample to be measured, an inner cylinder having a smooth surface may be preferable. For this reason, an inner cylinder 1 having a spiral groove 1a and an inner cylinder 1 having a smooth surface are prepared. Preferably, it can be exchanged accordingly.

Further, in order to quantitatively supply the liquid to be measured, for example, a liquid supply device 12 (see FIG. 2) such as an electric burette or a metering pump is provided, and an annular recess 13 between the inner and outer cylinders 1 and 2 is provided. Preferably, a liquid is supplied into the interior. With this configuration, the liquid sample can be supplied at a constant rate, and the change in viscosity can be measured while continuously changing the mixing ratio of the liquid sample.

The usage of the measuring device will be described below.

First, a fixed amount of a liquid sample (for example, 10c
c) is weighed into the outer cylinder 2. At this time, of the liquid sample, one of the dispersion medium and the dispersoid can be weighed in the outer cylinder 2 and the other can be supplied by the liquid supply device 12. It is to be noted that, if these are collected and weighed in the outer cylinder 2 from the beginning without being divided into the dispersion medium and the dispersoid, measurement can be performed even when the dispersoid is a solid.

Next, the outer cylinder 2 on which the liquid sample has been weighed is set on the thermostat 8. Then, the pedestal 6 is lowered, and the vertical position of the inner cylinder 1 is set.
When 0 is moved in the horizontal direction, the relative position between the inner cylinder 1 and the outer cylinder 2 is determined, and the size of the narrow portion 13a is determined. Further, if necessary, a liquid supply device 12 such as an electric buret is set.

Subsequently, the rotation of the inner and outer cylinders 1 and 2 is started, and while the liquid sample is being stirred in the narrow portion 13a, the torque at this time is observed, and the change in viscosity of the liquid sample is continuously measured.
At this time, when a liquid serving as a dispersoid, for example, water is supplied at a constant speed by a liquid supply device 12 such as an electric burette, for example, the mixing ratio of a liquid sample such as printing ink, that is, the water content is continuously changed. While the viscosity can be measured.

Further, the liquid sample has a viscoelastic property,
When there is a danger that the liquid sample is wrapped around the outer surface of the inner cylinder 1 and rises to the shaft portion of the inner cylinder 1 and scatters around, using the inner cylinder 1 having a spiral groove 1a (see FIG. 4), The sample is pushed down, and the measurement can be performed smoothly.

In addition, in order to obtain the viscosity of the liquid sample in the stirring state from the torque detected by the torque detecting section 4, the viscosity standard liquid is previously measured by the above-described measuring device for each viscosity measurement solution as shown in FIG. -Measure the torque relationship and determine from this result.

Next, an example of measuring the viscosity while emulsifying the lithographic ink will be described.

Example 1 10 cc of the lithographic inks were weighed into the outer cylinder 2 and water was supplied at a constant speed by a liquid supply device 12 to emulsify, thereby reproducing the same emulsified state as in actual printing. The "torque-time curve" of the lithographic ink at this time was measured. In this case, when the water content at each time was calculated from the water supply speed, “torque-water content curves” (a) and (b) shown in FIG. 6 were obtained.

In general, a lithographic ink acts on moist water on a printing press and becomes 20 to 30% when the water content is high. In the lithographic ink shown in FIG. 6A, when the amount of supplied water increases and the water content exceeds 20%, the torque decreases, and the density (the film thickness of the ink) when printed may decrease. Understand.

On the other hand, the lithographic ink indicated by (b) in FIG. 6 does not decrease the torque and the ink density does not decrease even if the water supply amount is increased and the water content exceeds 20%. You can see that.

Embodiment 2 FIG. Using a lithographic printing ink different from that of Example 1 as a liquid sample, the viscosity was measured while emulsifying in substantially the same manner as in Example 1 except for the following conditions. (1) The "torque-time curve" (c) shown in FIG. 7 was measured using only the printing ink as a liquid sample without supplying water. (2) The "torque-time curve" (d) shown in FIG. 7 was measured while replacing the liquid sample and supplying water. (3) The ratio [(d) / (c)] of the torque of the curve (d) of (2) to the curve (c) of (1) was calculated. (4) Calculate the water content at each time from the water supply rate,
When a graph was created with the torque ratio calculated in (3), a "torque ratio-water content curve" (e) shown in FIG. 8 was obtained.

[0039]

As described above in detail, the present invention provides a liquid sample to be measured in which a narrow portion is formed in a part of an annular space formed between an inner cylinder and an outer cylinder rotating with a speed difference. And the viscosity of the liquid sample at the time of the stirring is measured by detecting the torque or the rotational driving force of one of the inner and outer cylinders while stirring the fluid while passing through the narrow portion. Therefore, the change in viscosity due to the stirring of the liquid sample can be continuously measured, and in particular, the change in viscosity while the printing ink such as an offset passes through each printing unit can be reliably obtained.

In the above description, the printing ink has been mainly described, but the present invention can be applied to a viscoelastic body and a liquid containing the same in addition to the printing ink.

Although the inner and outer cylinders are shown as having a cylindrical shape as a center, any other shapes, such as polygons of triangles or more, may be used as long as a narrow portion can be formed in a part of the annular space. Can also be configured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the principle of the present invention in cross section.

FIG. 2 is a front view of an example of an apparatus for implementing the present invention.

FIG. 3 is a side view of the device shown in FIG. 2;

FIG. 4 is an explanatory view showing a part of an apparatus according to another embodiment of the present invention.

FIG. 5 is a graph showing a relationship between torque acting on an inner cylinder and viscosity.

FIG. 6 is a graph showing a relationship between a water content and a torque.

FIG. 7 is a graph showing the relationship between stirring time and torque.

FIG. 8 is a graph showing a relationship between a water content and a torque ratio.

FIG. 9 is a graph showing a size (mm) of a narrow portion and a given shear rate (1 / sec).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner cylinder 1a Spiral groove 2 Outer cylinder 3 Bearing 4 Torque detector 5 Driving motor 6 Pedestal 7 Motor 8 Constant temperature bath 9 Outer cylinder driving motor 10 Pedestal 11 Feed screw 12 Liquid supply device 13 annular recess 13a narrow part

Continuation of the front page (56) References JP-A-62-140047 (JP, A) JP-A-56-58546 (JP, A) Jpn. Development of New Rheology Measuring Apparatus for Ink, ”Journal of the Society of Rheology, Japan Society of Rheology, 1999, Vol. 227-234 Tsutomu Horiyume, Takenobu Isoda, "Development of New Rheology Measuring Device for Printing Ink", DIC Technical Review, Dainippon Ink and Chemicals, Ltd., 2000, No. 6, pp. 1-8 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 11/00-11/16 B01F 9/00-13/10 JICST file (JOIS)

Claims (7)

(57) [Claims] 1. A narrow portion is formed in a part of an annular space between rotating inner and outer cylinders, a liquid to be measured is put into the annular space, and then the inner and outer cylinders are rotated with a speed difference. While stirring the fluid in the narrow portion, the torque or the rotational driving force of any one of the inner and outer cylinders is detected,
A method of measuring the viscosity of a liquid while stirring the liquid, wherein the viscosity of the fluid is obtained from the detected value. 2. The method for measuring the viscosity of a liquid while stirring the liquid according to claim 1, wherein the width of the narrow portion is adjusted according to the properties of the liquid. 3. An inner cylinder that rotates with a speed difference compared to the rotation speed of the outer cylinder is arranged in the outer cylinder so as to be parallel to the rotation axis of the outer cylinder and spaced apart by a predetermined distance; An apparatus for measuring the viscosity of a liquid while stirring the liquid, further comprising a detector for detecting the torque applied to the inner cylinder and / or the electric power of a motor for driving the inner cylinder. 4. The apparatus for measuring viscosity of a liquid while stirring the liquid according to claim 3, wherein the outer cylinder and the inner cylinder are formed in a cylindrical shape. 5. The viscosity of a liquid according to claim 3 or 4, wherein the distance between the inner surface of the outer cylinder and the outer surface of the inner cylinder can be adjusted. Equipment to do. 6. A spiral groove which is provided on an outer surface of the inner cylinder in a direction in which a downward force acts on a liquid attached to the inner cylinder during rotation. Or a device for measuring the viscosity of the liquid while stirring it. 7. A liquid supply device for supplying a liquid quantitatively between said inner and outer cylinders.
Or a device for measuring the viscosity of the liquid while stirring it.