JPH11281558A - Apparatus and method for evaluation of characteristic of emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To an apparatus and a method, for the evaluation of the characteristic of an emulsion, in which the physical property of the emulsion having a correlative property with the sensitivity of a human being can be measured with high reliability and with good reproducibility and in which the characteristic of the emulsion can be evaluated objectively instead of a sensory analysis which depends on the sensitivity of the human being as in the case of cosmetics. SOLUTION: A moving plate 12, a probe 14, an elastic member 16 whose lower end is fixed to the probe 14 and which is extended up and down, a probe pressing device 18, a back and forth moving device 20 and a measuring device 22 which measures a sliding force acting on the probe 14 are provided. The rear surface of the probe 14 is formed on an arc face around the horizontal axis (Z) at right angles to the sliding direction of the probe 14. Thereby, even when the elastic member 16 is elastically deformed by a sliding resistance (R) so as to tilt the probe 14, the shape in the contact part of the arc face of the probe 14 with the moving plate 12 is not changed. A vertical force (F) which acts during this time is constant. The probe 14 is not hooked by its back and forth moving operation because it has the arc face. Consequently, the characteristic of an emulsion can be measured on the basis of a change in the sliding force which is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a characteristic evaluation apparatus and method for objectively evaluating the characteristics of an emulsion instead of a sensory test relying on human sensitivity.

[0002]

2. Description of the Related Art Emulsions, which are liquids that are immiscible with each other, such as oil and water, are known as milk, mayonnaise,
It is widely used from foods such as cream, cosmetic creams, emulsions and gels to familiar products such as paints, adhesives, medical products, agricultural chemicals, and asphalt (civil engineering materials).

In general, when an emulsion is left undisturbed, dispersed particles are separated from each other via an unstable process such as creaming, agglomeration and coalescence, and are separated into two original liquids. Therefore, when an emulsion is used for industrial purposes, it is naturally chemically stable, but hard,
Evaluation from the viewpoint of mechanical properties such as fluidity and deformation is important.

[0004] The viscosity in the steady state can be measured by a viscometer, but in the case of an emulsion whose viscosity changes during use, the use of the emulsion has relied on a sensory test based on the interval between skilled panelists. Although human sensory organs have good sensitivity, they have the drawback that they are greatly affected by health conditions, individual differences, environment, etc., and have large variations in data and lack credibility.

In order to solve such problems, the inventors of the present invention have previously devised and applied for a means for evaluating the phase inversion of an emulsion (Japanese Patent Application Laid-Open Nos. 3-262941 and 4-43941). JP-A-4-60438, JP-A-5-60438
-60677). FIG. 6 is a schematic view of an apparatus according to the prior application, wherein (A), (B), (C), and (D) show JP-A-3-262941 and JP-A-4-43941, respectively.
, JP-A-4-60438 and JP-A-5-60677. In each of the drawings, components having substantially the same functions are denoted by the same reference numerals.

For example, the means disclosed in Japanese Patent Application Laid-Open No. 4-43941 has a movable plate 1, a fixed plate 2, a sensor means 3, and a fan means 4 as shown in FIG. Plate 1 and fixed plate 2
Are relatively slid, and the phase change of the emulsion is evaluated from the ratio of the sliding direction force applied to the fixed plate 2 to the speed of the movable plate. In this figure, 5 is a spring mechanism, 6 is an elevating mechanism, and 7 is a bearing. By this means, the phase inversion process of the emulsion, which could not be quantitatively measured by the conventional viscometer, can be objectively evaluated.

[0007]

In the above-mentioned conventional means, the fixed plate 2 (hereinafter referred to as a probe) is separated from the movable plate 1 by a fixed distance, or the probe 2 is pressed against the movable plate 1 with a fixed force. Movable plate 1
In order to reciprocate in the in-plane direction, it is necessary to accurately guide the probe 2 with respect to the movable plate 1 so that the opposing surface always keeps exactly parallel. Therefore, it is necessary to increase the rigidity of the shafts 2a and 2b that support the probe 2 and to increase the guiding accuracy of the bearing 7.

However, as a result, since the rigidity of the shaft 2a is high, the generated stress is very small, and there is a problem that the accuracy of measuring the load by the sensor means 3 (for example, a strain gauge) is reduced. Also, since the guiding accuracy by the bearing portion 7 is high, the shaft 2b
There is also a problem that the vertical movement resistance is large and cannot follow a slight load change. Further, if the shaft rigidity is reduced to increase the measurement accuracy, the probe 2 is inclined by the sliding resistance, and the probe is easily squeezed or caught by the reciprocating motion, which causes a problem that the measurement accuracy is further reduced. Further, as shown in FIGS. 6 (C) and 6 (D), when the movable plate 1 is moved in only one direction with respect to the probe 2 in order to prevent the probe from being caught, the finger is directly applied to the skin with a finger. In the emulsion, there is a problem that the correlation between the obtained data and the sensitivity is lost.

Therefore, in the conventional means, in order to objectively evaluate the physical properties of an emulsion having a correlation with human sensibility, there is a problem that measurement accuracy is low, data variation is large, and reproducibility is low. .

The present invention has been made to solve the above-mentioned problems. That is, the object of the present invention is:
Emulsions that can measure the physical properties of emulsions that correlate with human sensibility with high accuracy and high reproducibility, and that can objectively evaluate their properties instead of sensory tests that rely on human sensitivities like cosmetics It is an object of the present invention to provide a characteristic evaluation device and method.

[0011]

According to the present invention, a movable plate having a horizontal upper surface, a probe contacting the upper surface of the movable plate, an elastic member having a lower end fixed to the probe and extending upward, A probe pressing device for holding the upper end of the elastic member and pressing the same downward, a reciprocating device for relatively reciprocating the movable plate and the probe pressing device relatively horizontally, and a sliding force acting on the probe by the reciprocating motion. A lower surface of the probe is formed in an arc surface centered on a horizontal axis perpendicular to the probe sliding direction, whereby the emulsion specimen is placed between the probe and the movable plate. There is provided an emulsion characteristic evaluation apparatus for evaluating the characteristics of an emulsion based on a change in a sliding force measured by sandwiching the emulsion.

According to the structure of the present invention, the lower surface of the probe is formed on an arc surface centered on the horizontal axis Z perpendicular to the probe sliding direction, and is provided at the lower end of the elastic member extending vertically. Since the probe is fixed and the probe is pressed downward via the elastic member, even if the elastic member is elastically deformed due to sliding resistance and the probe is tilted, the shape change of the contact portion between the arc surface of the probe and the movable plate And the vertical force acting between them is kept constant. Further, since the lower surface of the probe is an arc surface, the probe is not caught by the reciprocating motion. Therefore, the accuracy can be greatly improved by reducing the rigidity of the elastic member (for example, by using an elastic flat plate) in order to increase the measurement accuracy. In addition, even if the probe is tilted, it does not affect the measurement accuracy, so that the vertical movement resistance of the probe can be reduced to improve the followability, and since the probe does not get caught, the reproducibility of the data is greatly improved. improves. Therefore, even in the case of a delicate emulsion such as a cosmetic cream that is applied directly to the skin with a finger, the change in resistance during reciprocating sliding, which has a high correlation with this, replaces the sensory test that relies on human sensitivity, Characteristics can be evaluated objectively.

According to a preferred embodiment of the present invention, the elastic member is an elastic flat plate having both surfaces in the probe sliding direction. With this configuration, the elastic deformation due to the sliding resistance of the elastic member can be increased, and the accuracy can be greatly improved. The measuring device includes a strain gauge attached to both surfaces of the elastic flat plate, and a calculating device that calculates a sliding force acting on the probe from an output of the strain gauge. With this configuration, the delicate and weak sliding resistance of the emulsion can be accurately calculated from the strain generated in the elastic flat plate.

Further, the probe pressing device includes a holding member for holding an upper end of the elastic member, a guide shaft having a lower end fixed to the holding member and extending upward, and a bearing portion for guiding the guide shaft to be vertically movable. Biasing means for biasing the guide shaft upward;
A weight which is concentrically mounted on the guide shaft and presses it downward. With this configuration, even if the probe is inclined, an accurate vertical force can always be applied to the probe by the urging means (for example, a spring) and the weight.

According to the present invention, a movable plate having a horizontal upper surface and reciprocating horizontally, and an arc surface centered on a horizontal axis which is in contact with the upper surface of the movable plate and is orthogonal to the sliding direction are formed. Sandwiching the emulsion specimen between the probe and the probe on the lower surface, measuring the sliding force acting on the probe by reciprocating the movable plate on the movable plate, and evaluating the characteristics of the emulsion from the change in the sliding force. A method for evaluating the characteristics of an emulsion is provided.

According to this method, since the lower surface of the probe is formed in an arc surface centered on the horizontal axis Z orthogonal to the probe sliding direction, the shape of the contact portion between the arc surface of the probe and the movable plate is formed. There is no change and the vertical force acting during this time is also kept constant. Further, since the lower surface of the probe is an arc surface, the probe is not caught by reciprocating motion, and the reproducibility of data is greatly improved.

Further, according to the present invention, (a) a probe having a lower surface with an arc surface centered on a horizontal axis perpendicular to the sliding direction, and a probe having both surfaces in the sliding direction and having a lower end fixed to the probe and And (b) pressing the probe downward on the horizontal upper surface of the movable plate that reciprocates horizontally via the elastic plate with the emulsion specimen interposed therebetween, and (c) placing the probe on the movable plate. The method of evaluating the characteristics of the emulsion is characterized in that the sliding force acting on the probe is measured by repeatedly reciprocating the above, and (d) the characteristics of the emulsion are evaluated from the change in the sliding force.

According to this method, the lower surface of the probe is formed in an arc surface centered on the horizontal axis Z perpendicular to the probe sliding direction, and the probe is fixed to the lower end of an elastic member extending in the vertical direction. Since the probe is pressed downward through the elastic member, even if the elastic member is elastically deformed due to sliding resistance and the probe is tilted, there is no change in the shape of the contact portion between the arc surface of the probe and the movable plate, The vertical force acting during this time is also kept constant. Further, since the lower surface of the probe is an arc surface, the probe is not caught by the reciprocating motion. Therefore, the accuracy can be greatly improved by reducing the rigidity of the elastic member (for example, by using an elastic flat plate) in order to increase the measurement accuracy. In addition, even if the probe is tilted, it does not affect the measurement accuracy, so that the vertical movement resistance of the probe can be reduced to improve the followability, and since the probe does not get caught, the reproducibility of the data is greatly improved. improves. Therefore, even in the case of a delicate emulsion such as a cosmetic cream that is applied directly to the skin with a finger, the change in resistance during reciprocating sliding, which has a high correlation with this, replaces the sensory test that relies on human sensitivity, Characteristics can be evaluated objectively.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted. FIG. 1 is an overall configuration diagram of an emulsion characteristic evaluation device of the present invention. As shown in this figure, the emulsion characteristic evaluation device 10 of the present invention includes a movable plate 12, a probe 14, an elastic member 16, a probe pressing device 18, a reciprocating device 20, and a measuring device 22.

The movable plate 12 is fixed to the upper surface of a carriage 21, and the carriage 21 is moved by a reciprocating device 20.
It reciprocates in the horizontal direction (left and right in this figure). In this example, the reciprocating device 20 includes a servomotor 20a, a ball screw 20b, a ball nut 20c, and the like. The servomotor 20a drives the ball screw 20b to rotate, and the reciprocating platform 2 on which the ball nut 20c is mounted.
1 is reciprocated so that the movable plate 12 and the probe pressing device 18 are relatively reciprocated horizontally. The present invention is not limited to this configuration, but may be configured such that the movable plate 12 is fixed and the probe pressing device 18 reciprocates.

Further, in this apparatus, as shown in this figure, a temperature controller 13 is sandwiched between the movable plate 12 and the carriage 21 to control the temperature of the movable plate 12.

The probe pressing device 18 includes a holding member 18a for holding the upper end of the elastic member 16, a guide shaft 18b having a lower end fixed to the holding member 18a and extending upward, and a guide shaft 18b.
a guide portion 18c for guiding the shaft b in a vertically movable manner;
and a weight 19 which is concentrically mounted on the guide shaft 18b and presses the same downward.
The upper end of the elastic member 16 is pinched and pressed downward.

The holding member 18a has a slit for inserting the upper end of the elastic member 16 from below and a screw member (for example, a bolt, not shown) for adjusting the interval between the slits. Hold the upper end firmly. The bearing portion 18c is attached to the fixed portion 17a (for example, the apparatus main body), has a bearing (not shown) therein, and guides the guide shaft 18b to move up and down with a very small resistance. In addition, the guide shaft 18b has a flange portion above the bearing portion 18c, and a weight 19 having a notch in the flange portion is concentrically mounted thereon. Further, a biasing means 18d (for example, a tension spring) is attached in a tension state between the fixed portion 17b and the guide shaft 18b, and biases the guide shaft 18b upward.

With this configuration, the urging means 18d and the weight 19 apply an accurate downward vertical force to the clamping metal 18a.
Thus, even if the elastic member 16 is deformed and the probe is tilted, an accurate downward vertical force F can always be applied to the probe.

FIG. 2A is an enlarged view of a portion A in FIG.
(B) is a side view thereof. As shown in FIGS. 1 and 2, the movable plate 12 has a horizontal upper surface 12a, and the probe 14 contacts the upper surface. In this example, the elastic member 16 is an elastic flat plate (for example, a spring plate) having both surfaces in the probe sliding direction (the left-right direction in FIG. 1), the lower end of which is fixed to the probe 14 and extends upward, and the upper end thereof. It is fixed to the clamp 18a.

Further, as shown in FIG. 2, the lower surface 14a of the probe 14 is formed as an arc surface having a radius r around a horizontal axis Z orthogonal to the probe sliding direction. The size of the radius r is arbitrary. For example, by setting it sufficiently small, it is possible to cope with large bending of the elastic member 16, and conversely, by setting it sufficiently large, the influence of the bending is minimized. Can be

In this example, the probe 14 is
A slit for inserting the lower end of the elastic member 16 from above, and a screw member (for example, a bolt,
(Not shown), and the lower end of the elastic member 16 is firmly held between the slits.

In FIG. 1, the measuring device 22 has a strain gauge 22a attached to both sides of the elastic flat plate 16, and a calculating device 22b for calculating a sliding force acting on the probe from an output of the strain gauge 22a. The sliding force acting on the probe due to the reciprocating motion is measured. With this configuration, the delicate and weak sliding resistance of the emulsion can be accurately calculated from the strain generated in the elastic flat plate 16.

In the above-described emulsion characteristic evaluation apparatus 10, the movable plate 12 and the probe 14
It is desirable to have chemical stability, impact resistance (thermal and mechanical), abrasion resistance, and to have a material and surface morphology suitable for the emulsion specimen and the evaluation purpose.
It is preferable to use a metal, a ceramic, or a polymer material alone or in combination.

In particular, it is preferable to attach an emulsion specimen and a film particularly suitable for evaluation purposes to one or both of the mutually sliding surfaces. For this film, for example, a tetrafluoroethylene film (PTFE) disclosed in the prior art can be used.

According to the present invention, the characteristics of the emulsion are evaluated by the following procedure using the above-structured emulsion characteristic evaluation apparatus. First, (a) the above-described probe 14
And an elastic flat plate 16 are prepared and set in the device 10 shown in FIG. Next, (b) the movable plate 1 that reciprocates horizontally
The probe 14 is pressed downward through the elastic flat plate 16 with the emulsion specimen sandwiched between the two horizontal upper surfaces 12a. Next, the device 10 is operated, and (c) the probe 1
4 is reciprocated repeatedly on the movable plate 12, and at the same time, the sliding force acting on the probe 14 is measured and recorded by the measuring device 22. Finally, (d) the characteristics of the emulsion are evaluated by comparing the change in the sliding force with the result of a sensory test conducted by a panel or the like prepared in advance or the measurement result of another emulsion obtained in the same manner.

FIGS. 3A and 3B are diagrams schematically showing the use state of the probe. FIG.
(B) shows the usage state of the conventional probe 15.
According to the apparatus and method of the present invention described above, the probe 14
Has a horizontal axis Z perpendicular to the probe sliding direction.
The probe 14 is fixed to a lower end of an elastic member 16 which is formed in an arc surface centered on and extends vertically.
Since the probe is pressed downward via the elastic member 16, even if the elastic member 16 is elastically deformed by the sliding resistance R and the probe 14 is tilted, the shape of the contact portion between the arc surface 14 a of the probe and the movable plate 12 is maintained. There is no change, the vertical force F acting during this period is constant, and the probe 14 is not caught by reciprocation because of the circular arc surface.
Therefore, the accuracy can be greatly improved by reducing the rigidity of the elastic member 16 (for example, by using an elastic flat plate) in order to increase the measurement accuracy. Further, even if the probe 14 is tilted, it does not affect the measurement accuracy. Therefore, by lowering the vertical movement resistance of the probe 14, the followability can be improved and the probe 14 is not caught. Reproducibility can also be greatly improved. Therefore, instead of a sensory test relying on human sensitivity from the change in resistance during reciprocating sliding, which is correlated with an emulsion such as a cosmetic cream applied directly to the skin with a finger, the characteristics can be objectively evaluated. .

In the method of the present invention, the elastic member 1
5 is not indispensable, and even when this is not used, the lower surface of the probe 14 is formed in an arc surface centered on a horizontal axis Z orthogonal to the probe sliding direction, so that the probe 14 can move with the arc surface of the probe 14. There is no change in the shape of the contact portion with the plate 12, and the vertical force acting during that time is also kept constant. Further, since the lower surface of the probe 14 is an arc surface, the probe is not caught by the reciprocating motion, and the reproducibility of data is greatly improved.

[0034]

EXAMPLES Examples using the apparatus for evaluating the characteristics of emulsion of the present invention will be described below. Table 1 shows a sensory evaluation comparison of the emulsion sample, that is, the measurement sample. As the measurement sample, two types of cleansing creams having different properties were used.

[0035]

[Table 1]

This test was performed by attaching a PTFE film to the lower surface of the probe 14 using the above-described apparatus.
The dimensions of the probe 14 of the present invention are 10 mm in width and 10 mm in radius r. The dimensions of the conventional probe 15 used as a comparative example are 10 mm in width and 3 mm in length of the contact surface.
Was used. Furthermore, a sliding speed of 1.2 cm / s, a sliding stroke of 20 mm, a stage temperature of 32 ° C., and a room temperature of 25
The test was performed at 50 ° C. and a relative humidity of 50% without using a fan.

FIG. 4 is an example of measurement data of the obtained sliding resistance. In this figure, (A) and (B) correspond to FIG.
When the measurement samples A and B are tested using the probe 14 of the present invention shown in FIG. 3, (C) and (D) show the same measurement samples A and B using the conventional probe 15 shown in FIG. Is a test. In each of the figures, the horizontal axis represents time, and the vertical broken lines on the vertical axis represent sliding resistance in the forward path and the return path.

4 (C) and 4 (D), it can be seen that in the vicinity indicated by the arrows in the figures, the variation in sliding resistance is large and accurate data is not obtained. This is because, in the conventional probe 15 shown in FIG. 3B, when the probe 15 is slightly tilted due to the sliding resistance, the probe and the movable plate 12 are moved.
It is considered that the shape of the contact portion greatly changes, and the probe is easily pryed or caught by the reciprocating motion. On the other hand, in FIGS. 4A and 4B, the sliding resistance shows almost the same value in the forward path and the return path, and it can be seen that accurate data is obtained and the reproducibility is high.

FIG. 5 shows an example of a change in sliding resistance obtained by using the above-described apparatus. In this figure, (A) uses the probe 14 shown in FIG. 2 (A) to test the measurement samples A and B, and (B) uses the conventional probe 15 shown in FIG. 3 (B). In this case, the same measurement samples A and B were tested, and this corresponds to the test of FIG. In each figure, the horizontal axis represents time, and the vertical axis represents the relative value of stress, ie, sliding resistance.

From this figure, the data of B in FIG.
"It becomes lighter once it gets heavier", measurement sample B
Well reproduces the sensory evaluation of
It can be seen that "lightens as it is", and the sensory evaluation of sample A is well reproduced. On the other hand, it can be seen that the data of A and B in FIG. 5B have large variations and poor reproducibility.

It should be noted that the present invention is not limited to the above-described embodiments and examples, and it is needless to say that various changes can be made without departing from the spirit of the present invention. In particular, in the above-described embodiment, the application to the cosmetic cream has been described. However, the application to the milky lotion and the gel can be similarly applied.

[0042]

As described above, the apparatus and method for evaluating the characteristics of an emulsion according to the present invention can measure the physical properties of an emulsion having a correlation with human sensitivity with high accuracy and high reproducibility. Thus, instead of the sensory test relying on human sensibility, it has an excellent effect that its characteristics can be objectively evaluated.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an apparatus for evaluating the characteristics of an emulsion of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a diagram schematically showing a use state of a probe.

FIG. 4 is an example of measured data of sliding resistance using the apparatus of the present invention.

FIG. 5 is an example of a change in sliding resistance obtained using the apparatus of the present invention.

FIG. 6 is a block diagram of a prior application filed by the inventors of the present invention.

[Explanation of symbols]

 Reference Signs List 1 movable plate 2 fixed plate (probe) 2a, 2b shaft 3 sensor means 4 fan means 5 spring mechanism 6 elevating mechanism 7 bearing unit 10 emulsion characteristic evaluation device 12 movable plate 12a upper surface 14 probe 14a lower surface 16 elastic member 18 probe pressing device 18a Clamping bracket 18b Guide shaft 18c Bearing 18d Urging means 19 Weight 20 Reciprocating device 21 Reciprocating table 22 Measuring device 22a Strain gauge 22b Computing device

Claims (6)

[Claims] 1. A movable plate having a horizontal upper surface, a probe contacting the upper surface of the movable plate, an elastic member having a lower end fixed to the probe and extending upward, and an upper end of the elastic member sandwiched between the movable member and the probe. A probe pressing device that presses downward, a reciprocating device that relatively horizontally reciprocates the movable plate and the probe pressing device, and a measuring device that measures a sliding force acting on the probe by the reciprocating motion, The lower surface of the probe is formed in an arc surface centered on a horizontal axis perpendicular to the sliding direction of the probe, whereby the change in the sliding force measured with the emulsion specimen sandwiched between the probe and the movable plate is obtained. An emulsion characteristic evaluation device for evaluating the characteristics of an emulsion. 2. The elastic member according to claim 1, wherein the elastic member is an elastic flat plate having both surfaces in a probe sliding direction.
3. An apparatus for evaluating the characteristics of an emulsion according to item 1. 3. The measuring device has a strain gauge attached to both surfaces of the elastic flat plate, and a calculating device that calculates a sliding force acting on a probe from an output of the strain gauge.
3. The apparatus for evaluating characteristics of an emulsion according to claim 2, wherein: 4. The probe pressing device according to claim 1, wherein the holding member holds the upper end of the elastic member, a guide shaft having a lower end fixed to the holding member and extending upward, and a bearing portion for guiding the guide shaft to be vertically movable. 3. The apparatus according to claim 2, further comprising: a biasing means for biasing the guide shaft upward, and a weight concentrically mounted on the guide shaft and pressing the guide shaft downward. 5. A movable plate having a horizontal upper surface and reciprocating horizontally, and a probe in contact with the upper surface of the movable plate and having an arc surface on its lower surface centered on a horizontal axis orthogonal to the sliding direction. An emulsion specimen is interposed therebetween, and the movable plate is reciprocated on the movable plate to measure a sliding force acting on the probe, and a characteristic of the emulsion is evaluated from a change in the sliding force. Characteristic evaluation method. 6. A probe having on its lower surface an arc surface centered on a horizontal axis orthogonal to the sliding direction, and an elastic flat plate having both surfaces in the sliding direction and having a lower end fixed to the probe and extending upward. And (b) pressing the probe downward through an elastic flat plate with the emulsion specimen interposed therebetween on the horizontal upper surface of the movable plate that reciprocates horizontally, and (c) repeatedly reciprocating the probe on the movable plate. And (d) evaluating the characteristics of the emulsion based on the change in the sliding force.