JP7112072B2 - Anti-drying tool for rotational rheometer - Google Patents

Description

The present invention relates to an anti-drying tool for rotary rheometers.

A rotational rheometer is known for measuring rheological properties such as viscosity and viscoelasticity of an object (sample) to be measured. In this rotational rheometer, rheological properties are generally measured by applying an external force to a sample and detecting deformation or stress occurring in the sample. More specifically, a sample is placed between a sensor composed of a pair of upper and lower discs, one of the discs is driven to rotate using a torque motor, and viscosity is measured based on parameters corresponding to deformation or stress occurring in the sample. - Calculate viscoelastic properties (for example, Patent Literature 1).

Japanese Patent Publication No. 2010-501838

By the way, when the rheological properties of a sample are measured using the rotational rheometer described above, the outer edge of the sample placed between the sensors consisting of a pair of upper and lower discs is exposed to the atmosphere. . Therefore, when measuring the viscoelasticity of a sample that tends to form a film due to drying, the outer edge of the sample dries, and the characteristics of the dried material are directly reflected in the torque, which may prevent accurate measurement. . Similarly, when measuring a sample that tends to harden due to drying, if a portion of the sample dries, accurate measurement may not be possible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a drying prevention tool for a rotational rheometer that can suppress the drying of a sample during measurement using a rotational rheometer and improve the measurement accuracy. and

A dryness prevention tool for a rotational rheometer according to one aspect of the present invention is a dryness prevention tool for a rotational rheometer that can be installed in a rotational rheometer for measuring the rheological properties of a sample, and comprises a sensor of the rotational rheometer The housing includes a substantially ring-shaped first side wall erected around the measuring section in a plan view, and an upper end of the first side wall. A first porous body impregnated with a solvent is provided on the measurement part side of the upper plate.

According to this aspect, when measuring the viscoelasticity of a sample under a heating condition using a rotational rheometer, for example, the upper plate covering the upper side of the measurement unit is heated, and the first The solvent impregnated in the porous body can evaporate into the housing. As a result, drying of the sample housed in the housing can be suppressed. Therefore, even if a sample that tends to form a film when dried is used, the viscoelasticity of the sample can be measured while suppressing drying of the sample. can. As a result, the accuracy of measurement using a rotational rheometer can be improved.

In the above aspect, a second porous body impregnated with a solvent may be provided on the inner peripheral surface of the first side wall.

According to this aspect, when measuring the viscoelasticity of a sample under a heating condition using a rotational rheometer, the solvent impregnated in the second porous body provided on the first side wall evaporates into the housing. can be made This makes it possible to further suppress drying of the sample accommodated in the housing.

In the above aspect, a second side wall for fixing the second porous body may be provided on the inner peripheral surface of the second porous body.

According to this aspect, since the second side wall is provided on the measurement section side of the second porous body, the second side wall can suppress the solvent leaking from the second porous body to the measurement section side.

In the above aspect, the second side wall may be provided with a plurality of holes formed through the inside thereof.

According to this aspect, the solvent impregnated in the second porous body can evaporate toward the measurement section through the holes formed in the second side wall, so that drying of the sample can be further suppressed. .

The above aspect may further include a container that covers the outside of the housing.

According to this aspect, when measuring the viscoelasticity of a sample under heating conditions using a rotational rheometer, the upper plate can be heated from above by the container covering the outside of the housing. transpiration of the solvent impregnated in the first porous body provided in the can be accelerated. This makes it possible to further suppress drying of the sample accommodated in the housing.

In the above aspect, the first porous body and the second porous body may be felt cloth.

According to this aspect, it is possible to provide a drying prevention tool for a rotational rheometer that suppresses an increase in cost.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide a drying prevention tool for a rotational rheometer that can suppress drying of a sample during measurement using a rotational rheometer and can improve measurement accuracy. .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a schematic configuration of a drying prevention tool for a rotational rheometer according to a first embodiment; 2 is a perspective view showing a state in which the upper plate shown in FIG. 1 is removed; FIG. 1 is a diagram schematically showing the configuration of the anti-drying tool for rotational rheometer of the first embodiment. FIG. FIG. 10 is a perspective view showing a schematic configuration of a drying prevention tool for a rotational rheometer according to a second embodiment; FIG. 4 is a diagram schematically showing the configuration of a drying prevention tool for a rotational rheometer according to a second embodiment; FIG. 10 is a diagram schematically showing the configuration of a drying prevention tool for a rotational rheometer according to a third embodiment; 4 is a graph showing changes over time in viscosity of an aqueous gelatin solution obtained by dynamic viscoelasticity measurement.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, the same reference numerals have the same or similar configurations.

<First Embodiment>
The configuration of the anti-drying tool for a rotational rheometer according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view showing a schematic configuration of the anti-drying tool for rotational rheometer of the first embodiment. FIG. 2 is a perspective view showing a state in which the upper plate shown in FIG. 1 is removed. FIG. 3 is a view showing the IV-IV cross section shown in FIG. 1, and is a view schematically showing the configuration of the anti-drying tool for the rotational rheometer. The illustration of the shaft 3 is omitted in FIG. 1, and the illustration of the shaft 3 and the upper sensor 2a is omitted in FIG.

As shown in FIG. 3, the rotational rheometer includes sensors 2a and 2b composed of a pair of upper and lower discs, and measures rheological properties of a sample S placed between the sensors 2a and 2b. Specifically, the upper sensor 2a is connected to the rotating shaft of a motor (not shown) via a shaft 3, and when the motor is driven, its driving force is transmitted to the shaft 3, causing the upper sensor 2a to rotate. do. By rotating the upper sensor 2a in this way, the stress (torque) and displacement occurring in the sample S placed between the sensors 2a and 2b are detected, and the rheological properties of the sample S are measured. The rotational rheometer in this embodiment includes heating means (not shown) capable of heating the sample S while the rheological properties of the sample S are being measured.

In this specification, the sensors 2a and 2b and the sample S, which are composed of a pair of upper and lower discs, constitute a measurement section M (hereinafter simply referred to as "measurement section M") of the rotational rheometer. be.

As shown in FIG. 3, the anti-drying tool 1 for a rotational rheometer includes a housing 10 forming a housing space R for housing a measuring section M therein.

The housing 10 is a cylindrical container, and is composed of a first side wall 10b erected around the measuring section M and an upper plate 10a installed on the upper end of the first side wall 10b.

The upper plate 10a is an upper lid that covers the upper side of the measuring section M. As shown in FIG. The upper plate 10a is composed of a pair of separable semicircular plate-like members, and has a generally circular shape in a plan view as a whole. A through hole 15 for passing the shaft 3 is formed in the center of the upper plate 10a. A porous body 11a (first porous body) capable of absorbing a solvent (for example, water) is attached to the upper plate 10a on the measurement part M side (the lower side of the upper plate 10a in FIG. 3). . The porous body 11a can be composed of, for example, a plate-shaped porous material along the back surface of the upper plate 10a, but the shape and size of the porous body 11a are not particularly limited and can be changed as appropriate. be.

The first side wall 10b is formed in a generally annular shape in a plan view so as to surround the measuring section M. As shown in FIG. A porous body 11b (second porous body) capable of absorbing a solvent (for example, water) is provided inside the first side wall 10b in the radial direction (that is, the side wall 10b on the measurement part M side). The porous body 11b is arranged along the inner peripheral surface of the first side wall 10b so as to cover the circumference of the measurement section M, as shown in FIG.

As shown in FIGS. 2 and 3, a substantially annular second side wall 12 is provided radially inward of the porous body 11b in a plan view and has a smaller radial dimension than the first side wall 10b. The second side wall 12 is detachably installed between the porous body 11b and the measuring section M. As shown in FIG. The porous body 11b is fixed in the gap between the second side wall 12 and the first side wall 10b by installing such a substantially annular second side wall 12 along the inner peripheral surface of the porous body 11b. can do.

A plurality of holes H are formed in the second side wall 12 as shown in FIG. A plurality of holes H are formed so as to communicate from the inner peripheral surface to the outer peripheral surface of the second side wall 12 . In this embodiment, since the porous body 11b is arranged along the outer peripheral surface of the second side wall 12, when the solvent contained in the porous body 11b evaporates, the hole H of the second side wall 12 It is possible to make it easier to circulate the evaporated solvent to the measurement part M side through the . As a result, drying of the sample S can be further suppressed.

Note that the porous bodies 11a and 11b can be appropriately changed as long as they have a large number of pores to the extent that they can retain the solvent that has been absorbed in advance. Examples of the porous material include felt cloth, non-woven fabric such as cotton puff, synthetic polymer sponge such as nitrile rubber and polyurethane, and porous ceramics such as alumina ceramics, but are not limited to these materials.

Although the first embodiment described above includes the porous body 11b and the second side wall 12 surrounding the circumference of the measurement section M, the configuration may be such that these members are not included. That is, the anti-drying tool for a rotary rheometer in this embodiment forms an accommodation space R for accommodating therein the sample S and the measurement part M including the sensors 2a and 2b for measuring the rheological properties of the sample S. A housing 10 is provided, and the housing 10 includes a first side wall 10b erected around the measuring section M, and an upper plate 10a disposed on the upper end of the first side wall 10b and covering the upper side of the measuring section M. A porous body 11a impregnated with a solvent may be provided on the lower side of the upper plate 10a.

<Second embodiment>
Next, the configuration of the anti-drying tool for rotational rheometer of the second embodiment will be described. FIG. 4 is a perspective view showing a schematic configuration of the anti-drying tool for rotational rheometer of the second embodiment. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4, and is a diagram schematically showing the configuration of the anti-drying tool for the rotary rheometer.

The anti-drying tool for rotational rheometer 1b shown in FIGS. 4 and 5 is obtained by adding a cylindrical container 20 to the anti-drying tool 1 for rotational rheometer shown in the first embodiment. And the function is the same as the anti-drying tool 1 for rotational rheometer of the first embodiment. Therefore, the same reference numerals as in the first embodiment are used for the same parts as in the dryness prevention tool for rotary rheometer 1 of the first embodiment, and the description thereof is omitted.

In the anti-drying tool 1b for a rotary rheometer shown in FIGS. 4 and 5, a cylindrical container 20 is provided to cover the outside of a housing 10 in which a measuring section M is housed. The cylindrical container 20 is a cover (hood) having a heating function, and by covering the housing 10 with this cover, it is possible to control the temperature of the housing 10 including the measurement unit M. there is For example, when measuring gelatin aqueous solution under predetermined heating conditions, the temperature is controlled by the heating/heating function provided in the cylindrical container 20 so that the inside of the cylindrical container 20 is maintained under the predetermined heating conditions. . By configuring in this way, when measuring, for example, an aqueous gelatin solution under heating conditions using a rotational rheometer, the cylindrical container 20 can be used to measure from the upper side to the upper side, compared to a configuration in which the cylindrical container 20 is not provided. It is possible to make it easier to heat the plate 10a. Therefore, the solvent can be easily evaporated from the porous body 11a attached to the upper plate 10a, and drying of the sample S can be further suppressed.

<Third Embodiment>
Next, the configuration of the anti-drying tool for rotational rheometer of the third embodiment will be described. FIG. 6 is a diagram schematically showing the configuration of the anti-drying tool for rotational rheometer of the third embodiment.

The anti-drying tool 1c for the rotary rheometer shown in FIG. are the same as the anti-drying tool 1b for the rotational rheometer of the second embodiment. Therefore, the same reference numerals as in the first embodiment are used for the same parts as in the anti-drying tool for rotary rheometer 1b of the second embodiment, and descriptions thereof are omitted.

A drying prevention tool 1c for a rotary rheometer shown in FIG. 6 includes a solvent supply device 30 for supplying a solvent to a porous body 11a attached to an upper plate 10a.

The solvent supply device 30 includes a reservoir 31 , a connecting pipe 32 and a liquid absorbing material 33 . The storage part 31 is a tank that stores a solvent (for example, water). The connecting pipe 32 is a conduit that connects between the reservoir 31 and the porous body 11a attached to the upper plate 10a and allows the solvent to flow therein. The liquid absorbing material 33 is provided inside the connecting pipe 32, and is a member for sucking up the solvent in the reservoir 31 by capillary action and supplying the solvent to the porous body 11a attached to the upper plate 10a. The liquid absorbing material 33 can be composed of, for example, a cloth-like body made of fibrous material, but is not limited to this, and various other materials can be used as long as they are members through which liquid can permeate due to capillary action. It is possible to adopt.

With this configuration, even if the solvent contained in the porous body 11a of the upper plate 10a evaporates and the porous body 11a dries, the solvent supply device 30 continues to supply the solvent to the porous body 11a. Therefore, drying of the sample S can be suppressed even when the measurement using the rotational rheometer takes a long time. As a result, the accuracy of measurement using the rotational rheometer can be further improved.

In addition, in the anti-drying tool 1c for a rotary rheometer shown in FIG. By doing so, the solvent supplied to the porous body 11a by the solvent supply device 30 can also be supplied to the porous body 11b through the porous body 11a. As a result, the solvent can evaporate from the porous bodies 11a and 11b for a longer period of time, and drying of the sample S can be further suppressed even in measurements that require a long period of time.

Hereinafter, the present invention will be described more specifically with specific examples and comparative examples. The following examples are merely illustrations for helping understanding of the present invention, and the scope of the present invention is not limited thereto.

[Example 1]
(1) Sample Preparation Granular gelatin (B type derived from bovine bone, manufactured by Nitta Gelatin Co., Ltd.) was dissolved in deionized water to prepare a 10% by mass gelatin aqueous solution. The gelatin aqueous solution was subdivided into about 1.5 mL portions and stored in an Eppendorf tube and stored in a refrigerator. The Eppendorf tube was heated at 60° C. for 30 minutes to melt the gelled gelatin before using it for the viscosity measurement.

(2) Viscosity measurement (2-1) Anti-drying tool The anti-drying tool 1b for the rotary rheometer described with reference to Figs. 4 and 5 was used. The upper plate 10a, the first side wall 10b, and the second side wall 12 shown in FIG. Felt cloth was pasted as the porous body 11a of the upper plate 10a and the porous body 11b surrounding the measuring portion M. As shown in FIG. A second side wall 12 for fixing the porous body 11b was provided on the inner peripheral surface side of the porous body 11b. Before the measurement using the rotary rheometer, the porous body 11a attached to the upper plate 10a and the porous body 11b surrounding the measuring portion M were impregnated with deionized water.

(2-2) Installation of sample Using a rotary rheometer (MCR302, manufactured by Anton Paar Co., Ltd.) equipped with a cone plate sensor (inner diameter 50 mm, cone angle 1 °) as the upper sensor 2a, the viscosity of the gelatin aqueous solution is measured. Measured in vibration mode. First, the temperature of the measurement part was set to 50°C. 0.6 mL of an aqueous gelatin solution heated to 60° C. was sucked up with a micropipette and poured into the lower sensor 2b (FIG. 5), and the upper sensor 2a was moved to a predetermined position. The upper plate 10a of the anti-drying tool 1 for rotary rheometer was placed on the first side wall 10b, and the cylindrical container 20 was moved to a predetermined position (see FIG. 4).

(2-3) Unification of Shear History After applying rotation at a shear rate of 60 s ^-1 for 60 seconds, the sensor was left stationary for 60 seconds to unify the shear history of the sample. In this step, the viscosities after 10 seconds and 60 seconds after the start of rotation were compared to determine whether there was a significant change in sample viscosity prior to subsequent dynamic viscoelasticity measurements. The ratio (%) of the viscosity after 60 seconds to the viscosity after 10 seconds from the start of rotation is defined as "viscosity ratio A".

(2-4) Viscosity Measurement Subsequently, dynamic viscoelasticity measurement was performed with a frequency controlled to 0.5 Hz and a shear stress of 0.5 Pa, and changes in viscosity were followed for 30 minutes. The ratio (%) of the viscosity after 10 minutes, 20 minutes, and 30 minutes to the viscosity at the start of the dynamic viscoelasticity is defined as "viscosity ratio B ₁₀ ", "viscosity ratio B ₂₀ ", and "viscosity ratio B 20 ", respectively. ratio B ₃₀ ”.

(3) Results The results of viscosity measurement are shown in Tables 1 and 2 (the same applies hereinafter). The viscosity ratio A was 99.1%, and no abnormal viscosity change occurred in a short time. The change in viscosity over time obtained by dynamic viscoelasticity measurement is indicated by a solid line G1 in FIG. The viscosity ratio B ₁₀ , the viscosity ratio B ₂₀ , and the viscosity ratio B ₃₀ calculated from the change in viscosity over time were 107%, 109%, and 110%, respectively. was within 10%.

[Example 2]
(1) Sample preparation It was carried out in the same manner as in Example 1.

(2) Viscosity measurement Measurement was performed in the same procedure and method as in Example 1, except that the cylindrical container 20 was not used.

(3) Results The viscosity ratio A was 98.5%, and no abnormal viscosity change occurred in a short time. The change in viscosity over time obtained by the dynamic viscoelasticity measurement is indicated by the dashed line G2 in FIG. The viscosity ratio B ₁₀ , viscosity ratio B ₂₀ , and viscosity ratio B ₃₀ calculated from the change in viscosity over time were 106%, 112%, and 121%, respectively.

[Example 3]
(1) Sample preparation It was carried out in the same manner as in Example 1.

(2) Viscosity Measurement Measurement was performed in the same procedure and method as in Example 1, except that the cylindrical container 20 was not used and the porous body 11b inside the first side wall 10b was removed.

(3) Results The viscosity ratio A was 98.6%, and no abnormal viscosity change occurred in a short time. The viscosity ratio B ₁₀ , viscosity ratio B ₂₀ , and viscosity ratio B ₃₀ calculated from the change in viscosity over time were 110%, 116%, and 135%, respectively.

[Comparative Example 1]
(1) Sample preparation It was carried out in the same manner as in Example 1.

(2) Viscosity measurement Measurement was performed in the same procedure and method as in Example 1, except that the cylindrical container 20 was not used and the top plate 10a (Fig. 3) was removed.

(3) Results The viscosity ratio A was 102%, and no abnormal viscosity change occurred in a short time. However, immediately after the transition to the dynamic viscoelasticity measurement, a rapid increase in the viscosity value due to drying was observed, and the viscosity ratio B10 reached 193%, so the dynamic viscoelasticity measurement was terminated in ₁₀ minutes.

[Comparative Example 2]
(1) Sample preparation It was carried out in the same manner as in Example 1.

(2) Viscosity measurement Measured by the same procedure and method as in Example 1, except that the anti-drying tools 1, 1b, and 1c for rotational rheometers described with reference to FIGS. 1 to 6 were not used. .

(3) Results The viscosity ratio A was 103%, and no abnormal viscosity change occurred in a short time. However, after moving to dynamic viscoelasticity measurement, an increase in viscosity due to drying was observed. The viscosity ratio B ₁₀ , the viscosity ratio B ₂₀ , and the viscosity ratio B ₃₀ calculated from the change in viscosity over time were 104%, 128%, and 196%, respectively. By later the viscosity increase was over 10%.

From the results shown in Example 3 and Comparative Examples 1 and 2, by providing the porous body 11a on the upper plate 10a that covers the upper side of the measurement section M, the solvent contained in the porous body 11b is evaporated and the sample S is formed. It can be seen that drying is suppressed, and as a result, it is possible to suppress an increase in the viscosity value.

From the results shown in Examples 2 and 3, in addition to providing the porous body 11a on the upper plate 10a covering the upper side of the measurement part M, it is better to provide the porous body 11b around the measurement part M. It can be seen that the amount of the solvent that evaporates into the housing 10 increases, and drying of the sample S can be further suppressed.

From the results shown in Examples 1 and 2, by providing the cylindrical container 20 covering the outside of the housing 10, when measuring the sample S under heating conditions using a rotational rheometer, the cylindrical container 20 By heating the upper plate 10a, evaporation of the solvent contained in the porous body 11b attached to the upper plate 10a is promoted, and drying of the sample S can be further suppressed.

A reference example in which the second side wall 12 (FIG. 3, etc.) is not installed will be described below.
[Reference example 1]
(1) Sample preparation It was carried out in the same manner as in Example 1.

(2) Viscosity measurement Measurement was performed by the same procedure and method as in Example 1, except that the following points were changed.
- The cylindrical container 20 was not used.
- The second side wall 12 (Fig. 3, etc.) was removed, and instead of placing a felt cloth inside the first side wall 10b, a twisted Kimwipe (manufactured by Nippon Paper Crecia Co., Ltd., product name) was placed.
- A Kimwipe (manufactured by Nippon Paper Crecia Co., Ltd., product name) was soaked in excess deionized water, and the overflowing water was allowed to reach the outer edge of the sensor 2 .

(3) Results Water overflowing from a Kimwipe (manufactured by Nippon Paper Crecia Co., Ltd., product name) contacted and mixed with the gelatin aqueous solution used as sample S, and the viscosity ratio A became 91.3%.

From the results shown in Reference Example 1, when the solvent flowing out from the porous body 11b arranged inside the first side wall 10b reaches the outer edge of the sensor 2, the solvent and the sample S are mixed, and the viscosity of the sample S decreases in a short time. I know you do. Therefore, as described with reference to FIGS. 1 to 3, by installing the second side wall 12 so that the porous body 11b is fixed in the gap between the first side wall 10b and the second side wall 12, , leakage of water from the porous body 11b toward the sensor 2 side can be prevented.

The embodiments described above are for facilitating the understanding of the present invention, and are not intended to limit and interpret the present invention. Each element included in the embodiment and its arrangement, materials, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Also, it is possible to partially replace or combine the configurations shown in different embodiments.

DESCRIPTION OF SYMBOLS 1... Anti-drying tool for rotational rheometer, 2... Sensor, 3... Shaft, 10... Housing, 10a... Housing, 10b... First side wall, 11a, 11b... Porous body, 12... Second side wall, 20 ... Cylindrical container, 30 ... Solvent supply device, M ... Measurement part, R ... Storage space, S ... Sample

Claims (4)

A drying prevention tool for a rotational rheometer that can be installed in a rotational rheometer for measuring the rheological properties of a sample,
A housing that forms a housing space for housing therein a measuring unit including a sensor of the rotational rheometer,
The housing has a substantially ring-shaped first side wall erected around the measuring section in a plan view, and an upper plate disposed on the upper end of the first side wall and covering the upper side of the measuring section,
A first porous body impregnated with a solvent is provided on the measurement part side of the upper plate ,
A second porous body impregnated with a solvent is provided on the inner peripheral surface of the first side wall,
A drying prevention tool for a rotary rheometer , wherein a second side wall for fixing the second porous body is provided on the inner peripheral surface of the second porous body . 2. The anti-drying tool for a rotary rheometer according to claim 1 , wherein the second side wall is provided with a plurality of holes penetrating through the inside thereof. 3. The anti-drying tool for rotary rheometer according to claim 1 , further comprising a container covering the outside of said housing. The anti-drying tool for a rotary rheometer according to any one of claims 1 to 3 , wherein said first porous body and said second porous body are felt cloth.

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