JPH0460438A - Method and apparatus for evaluating phase inversion of emulsion - Google Patents

Abstract

PURPOSE:To enable objective evaluation of a process of phase inversion of emulsion by computing the ratio between a force in the sliding direction applied to a fixed plate and speed of a movable plate. CONSTITUTION:An apparatus comprises a movable plate 1 rotating at a prescribed speed around a point A, a fixed plate 2 holding a sample together with the movable plate 1, a sensor 3 measuring a force applied to the fixed plate 2 from the sample, an air fan 4 sending air onto the surface of the sample for facilitating vaporization of a volatile component in the sample, a spring applying a prescribed pressure to the fixed plate 2, and an elevation mechanism 6 for moving the fixed plate 2 vertically. The two plates 1 and 2 are made slide in rotation relatively with a specimen held therebetween and computation is made on the basis of the ratio between the force in the sliding direction applied to the fixed plate 2 and the speed of the movable plate 1. Thereby a process of phase inversion of emulsion can be evaluated objectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for evaluating phase inversion processes of emulsions.

(Prior Art and Problems to be Solved by the Invention) Emulsions, which are coexisting bodies of immiscible liquids such as oil and water, range from familiar foods such as milk, mayonnaise, and cream, to paints, and cosmetic creams. It is used in a wide range of industrial products such as adhesives, pharmaceuticals, agricultural chemicals, and asphalt (civil engineering material).

Generally, if an emulsion is left undisturbed, the dispersed particles will separate from each other through unstable processes such as creaming, agglomeration, and coalescence, and will separate into two liquids.

When trying to use emulsions in industry, it is important not only to ensure that they are chemically stable, but also to evaluate them from the viewpoint of mechanical properties such as hardness, fluidity, and deformation.

Steady state viscosity can be measured by a viscometer,
In the case of emulsions whose viscosity changes during use, whether the emulsion is good or bad in use depends on sensory tests based on the senses of experienced panelists.

Human sense organs are highly sensitive, but they are highly sensitive to health conditions, individual differences, the environment, etc., and the drawback is that the data is highly variable and lacks credibility.

Therefore, an object of the present invention is to provide a method and apparatus that can objectively evaluate the phase inversion process of an emulsion, which could not be quantitatively measured using a conventional viscometer.

(Means for Solving the Problem) The above problem consists of a movable plate that rotates, a fixed plate spaced apart from the movable plate at a certain distance, and a sensor means for detecting a force applied in the rotational direction of the fixed plate. , a fan means for blowing air to the emulsion specimen supplied between the movable plate and the fixed plate to continuously change the composition of the emulsion; The present invention is solved by a phase change evaluation device characterized in that the phase change of the emulsion is evaluated from the ratio of the sliding direction force applied to the fixed plate and the speed of the movable plate.

According to another aspect of the present invention, an emulsion specimen is supplied between two plates spaced apart from each other by a certain distance, and while the composition of the emulsion specimen is continuously changed by blowing air onto the emulsion specimen, A phase inversion characterized in that the two plates are rotated and slid relative to each other with a specimen in between, and the phase inversion of the emulsion is evaluated from the ratio of the sliding direction force applied to the plates and the sliding motion speed. Provide an evaluation method.

(Example) In order to explain the method of the present invention in detail, an example performed using an apparatus for carrying out the method of the present invention will be described.

FIG. 1 shows an example of the configuration of the apparatus of the present invention.

The apparatus of the present invention includes a movable plate 1 that rotates at a constant speed around point A, a fixed plate 2 that holds a sample together with the movable plate 1, a sensor 3 that measures the force exerted by the sample on the fixed plate 2, and a sample. A blower fan 4 for blowing air onto the surface to promote evaporation of volatile components in the sample; a spring mechanism 5 for applying a constant pressure to the fixed plate 2;
It consists of a lifting mechanism 6 for raising and lowering the fixed plate 2.

FIG. 2 shows the results of force amplitude plotted against the logarithm of time. The process of phase inversion can be understood from the start time and change width of this force amplitude.

The two plates used in the present invention have chemical stability, impact resistance (thermal and mechanical), and abrasion resistance in terms of materials, and are also made of materials and surface morphology that are suitable for the specimen and evaluation purpose. It is desirable to have one.

Although metals, ceramics, and polymers can be used alone as materials, it is preferable to use them in combination.

Metals include aluminum, stainless steel, copper, etc. Ceramics include glass, quartz, etc. Polymers include polyethylene, polystyrene, polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, and polyacetic acid. Vinyl compounds and addition polymers of vinyl compounds such as vinyl, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, vinylidene fluoride/trifluoroethylene copolymer, ethylene/tetrafluoroethylene copolymer, vinylidene fluoride Copolymers of vinyl compounds or fluorine compounds such as /tetrafluoroethylene copolymers, vinylidene cyanide/vinyl acetate copolymers, compounds containing fluorine such as polytrifluoroethylene, polytetrafluoroethylene, polyhexafluoropropylene, nylon 6. Polyamide such as nylon 66, polyimide, polyurethane, polyester such as polyethylene terephthalate, polyester,
Polyethers such as polycarbonate, polyoxymethylene, polyethylene oxide, polypropylene oxide,
Further, thermosetting resins such as unsaturated polyester, epoxy, Bakelite, etc. can be mentioned.

More specifically, the metal plate can be used as it is after being cut, but it can also be used after being subjected to treatments such as vapor deposition or plating with different metals. The cut resin can be used as is, but it can also be used after chemical etching, corona treatment, or plasma treatment to change the chemical properties of the surface. Films that can be formed into films by casting or extrusion can also be used as they are, but alkali metal solution treatment, alkali metal amalgam method, chemical etching such as electrolytic etching, silver/
It is possible to use materials that have been subjected to metal vapor deposition such as aluminum, vacuum discharge treatment, (reverse) sputter etching, corona treatment, graft treatment, plasma treatment, sandblasting treatment, or the like.

Among these, a particularly suitable plate material is a fluorine-based film that has been chemically etched or (reverse) sputtered, taking into account its flexibility, chemical stability, impact resistance (thermal and mechanical), and abrasion resistance. It will be done.

Example 1 An untreated tetrafluoroethylene film (hereinafter referred to as PTFE) having a thickness of 15 μm was reverse sputtered using a sputtering device to obtain a sputter etched film. As a result of SEM observation, the surface of the sputtered film was uniformly raised (0.5 to 1
．． 0μm). The membrane surface showed hydrophilicity.

This membrane was attached to the plate of this device, and the phase inversion process of a cosmetic and nutritional cream (commercial product G) from oil-in-water type to water-in-oil type was measured multiple times at room temperature and under ventilation conditions. We looked at the reproducibility of. The results are shown in Figure 3.

In Figure 3, the horizontal axis is the number of rotations of the plate (logN
), and the vertical axis indicates shear force (logf). The rotation speed of the plate was 9 revolutions per minute, and one measurement was completed at 230 revolutions in about 25 minutes. Although some deviations are observed in the phase inversion time, it can be seen that the reproducibility of the phase inversion behavior is good overall.

Example 2 An untreated PTFE film with a thickness of 15 μm was treated with a complex compound solution made from a tetrahydrofuran solution of naphthalene and metallic sodium, and washed with water to obtain a chemically etched film. As a result of SEM observation, no remarkable change was observed on the etched surface. The membrane surface changes color from white to brown. The treated surface showed hydrophilicity. This measuring device was attached to the plate part, and using the same experimental method as in Example 1, different types of cosmetics were tested, as well as creams with a good and bad feeling of use for which the sensory test results were known by five panelists. We compared the measurement data with the panelists' tactile data. All creams are oil-in-water type.

Table 1 shows the sensory test results for two types of nutritional creams (commercial products A and B) and cleansing emulsion (commercial products C and D), and the results of measurement using the apparatus are shown in FIGS. 4 and 5. All specimens were oil-in-water emulsions.

As is clear from FIG. 4, FIG. 5, and Table 1, there is a clear difference in the measurement charts of the creams with a good feel and those with a bad feeling. In addition, good agreement was observed with the tactile sensation chart of female panelists, and the changes in sensory firmness were observed well (
I found that it was reproducing. As described above, this measuring device is capable of objectively evaluating the phase inversion process of an emulsion, which could not be quantitatively measured using a conventional viscometer.

Example 3 In the same manner as in Example 2, a PTFE film was treated with a liquid ammonium solution of metallic sodium to obtain a chemically etched film. Using the same experimental method as in Example 1, the phase inversion process of nutritional cream (commercial product F) was measured under air blowing.

The results are shown in Figure 6.

In FIG. 6, although the two peak positions match well, there are differences in the rise and fall of the shear forces before and after. This means that although the cosmetic cream used here uses two types of surfactants, water-in-oil and oil-in-water, which have low activity, phase inversion behavior occurs very early in phase inversion. This is because it largely depends on the emulsion composition and form.

In the examples, the surface of the sputtered PTFE film is -F, and the surface of the chemically etched film is 10.

(Effects of the Invention) The method and device of the present invention enable continuous measurement of changes in the mechanical properties of a system whose composition ratio changes over time, making it possible to perform objective evaluation in place of conventional human sensory evaluation. .

[Brief explanation of the drawing]

Fig. 1 shows an example of the configuration of the device of the present invention, Fig. 2 is a diagram showing the relationship between force amplitude and time of the device of the present invention, and Fig. 3 shows nutrition measured using the device of the present invention. Fig. 4 shows the reproducibility of the phase inversion behavior of the cream (commercial product G). B) is a comparison diagram of the phase inversion process, and FIG. 5 shows the phase inversion process of a cleansing emulsion with good feel (commercial product C) and a bad cleansing emulsion (commercial product D) measured using the device of the present invention. FIG. 6 is a diagram showing the reproducibility of the phase inversion behavior of nutritional cream (commercial product F) measured using the apparatus of the present invention. l...Movable plate, fixed plate, sensor 3, ventilation fan, spring mechanism 5, lifting mechanism 6 Copy of drawing (no change in content) Copy of drawing in Figure 1 (no change in content) ■ 0g N Figure 3 Engraving of the drawing in Figure 2 (no change in content) v og N Clean IF of the drawing in Figure 4 (no change in content) f ■ Procedural amendment (method) % formula % ■, Indication of case 1990 Patent Application No. 170790 No. 2, Name of the invention Emulsion phase inversion evaluation method and device 3, Person making the amendment Name of applicant related to the case RIKEN 4, Agent 7, Contents of the amendment No change in content) Ve og N

Claims (4)

[Claims] (1) A movable plate that rotates, a fixed plate spaced apart from the movable plate at a certain distance, and a sensor means for detecting a force applied in the rotational direction of the fixed plate;
a fan means for blowing air to the emulsion specimen supplied between the movable plate and the fixed plate to continuously change the composition of the emulsion; A phase change evaluation device, characterized in that the emulsion is rotated and slid, and the phase change of the emulsion is evaluated from the ratio of the force in the sliding direction applied to the fixed plate and the speed of the movable plate. (2) Adjust the temperature of the movable plate from -20℃ to 100℃.
2. The apparatus according to claim 1, further comprising temperature control means for selectively setting or changing the temperature within a range of .degree. (3) A membrane member having a component composition and surface structure selected according to the component composition, form, and evaluation purpose of the specimen is attached to the opposing surfaces of the two plates.
The apparatus according to claim 1 or 2, characterized in that: (4) An emulsion specimen is supplied between two plates separated by a fixed interval, and the above two plates are placed with the specimen in between while blowing air to the emulsion specimen to continuously change its composition. A phase inversion evaluation method comprising: rotating and sliding the emulsion relatively, and evaluating the phase inversion of the emulsion from the ratio of the force in the sliding direction applied to the plate and the sliding motion speed.