JP2008070382A - Method of evaluating performance of mascara - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for objectively evaluating performance such as styling performance of mascara. <P>SOLUTION: In this method for evaluating the performance of the mascara, measurement of a force required for stretching a liquid is carried out by measuring a force generated in roll shafts perpendicularly to a plane including the both roll shafts when the liquid is divided in a nip formed by at least two rolls including a drive roll and a free-rotation or synchronous-rotation roll. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mascara performance evaluation and quality control method.

  Mascara is a product in which powder, polymer, wax, or the like is dispersed or dissolved, and its production includes complicated processes such as mixing and dispersion. In addition, there are many types of raw materials used, and in the manufacturing process, the raw materials interact in a complicated manner, and the performance of the final product is obtained by controlling them.

  The important mascara performance includes coloring performance, styling performance, durability / water resistance performance, etc., which are important performance appealing to consumers. Conventionally, comparative evaluation in actual use has been mainly used for such performance evaluation, and the result often varies depending on the individual and the state of eyelashes from time to time.

  Therefore, there has been a demand for a method that can objectively evaluate each performance, using as an index the physical property factors that should be the basis for expressing mascara performance such as styling performance.

  An object of the present invention is to provide a method capable of objectively evaluating mascara performance such as styling performance and coloring performance.

The liquid physical properties related to the styling performance of mascara are not only shear properties that can be measured with a normal viscometer or a viscoelasticity measuring device (rheometer), but this shear property is an expression mechanism. It was considered that different so-called stretched physical properties were involved, and based on this idea, an evaluation method for the above performance was examined.
As a method for evaluating a liquid related to elongation physical properties, a method of estimating the elongation viscosity from the strength of the stringiness of the liquid has become common. However, in the case of mascara, it is a dispersion having nonlinear viscoelasticity, and therefore it is difficult to correctly estimate the size of the extended physical properties such as elongation viscosity from the tendency of spinnability and to give an order to the size. I found that there was. Therefore, the present inventors have made various studies, and if the force required to elongate the mascara liquid is measured, the measured value is highly correlated with the performance of the eyelash styling of the mascara, that is, an index for evaluating the performance of the mascara. It was found that performance evaluation and quality control of mascara can be performed using this.

  That is, the present invention provides a mascara performance evaluation method and a quality control method characterized by measuring the force required to elongate the liquid.

  According to the present invention, product performance such as styling performance for mascara eyelashes can be objectively evaluated with high reproducibility using the force required for extending the liquid as an index, which can be easily measured using an existing apparatus. . Therefore, by using this method, it is possible to easily inspect the performance change at the time of manufacture and storage, so that the quality control of the product becomes possible.

The mascara performance evaluation method and quality control method of the present invention measure the force required to elongate the liquid.
Here, the “force required to elongate the liquid” refers to stress generated against the elongation deformation of the liquid, and the elongation viscosity or elongation elasticity of the liquid is related to this expression. For example, the tensile stress measured using a tensilon, a counter nozzle, etc., the 1st normal stress difference measured using a special rheometer, etc. are mentioned. In addition, a force perpendicular to a plane including both roll axes generated when the liquid splits between nips formed by at least two rolls of a drive roll and a free rotation or synchronous rotation roll (so-called tack) Value) is also one of the forms of elongational stress.

The “force required for extending the liquid” in the present invention may be measured by any of these methods. However, at least the drive roll has a wide measurable range and allows simpler measurement. And measuring the force (tack value) perpendicular to the plane including both roll axes generated at the roll axis when the liquid splits between nips formed by two rolls of free-rotation or synchronous-rotation rolls. Is preferred.
Hereinafter, taking the tack value as an example, the measurement of “force required for extending the liquid” of the present invention will be described.

The tack value is measured by providing at least two rolls, one of which is a drive roll and the other is a free rotation or synchronous rotation roll. A device that can pass through (see FIG. 1) is used, and a typical example thereof is an incometer used for evaluating the adhesiveness of printing ink. The apparatus preferably uses an incometer (see FIG. 1) having a vibration roll as a third roll in addition to the driving roll and the free-rotating or synchronous rotating roll. This is because when the vibration roll as the third roll exists, the liquid can be spread evenly on the drive roll, and a uniform and thin film can be formed in a short time.
Various materials such as metal, rubber and leather can be used for each roll. Each roll surface can also be used after being subjected to various water repellent and hydrophilic treatments.

  If the amount of the liquid loaded on the roll surface is too large, the free-rotating roll slips easily, and if it is too small, it is difficult to evenly spread on the roll. That is, the thickness of the coating film of the sample solution formed on the roll is preferably as thin as possible and uniform on the roll. These are particularly suitable for evaluating the liquid properties of low viscosity products. The thickness of the coating film is preferably 50 microns or less, more preferably 30 microns or less. Depending on the properties of the liquid, it is more preferably 20 microns or less. Since liquid drying becomes faster, this operation needs to be performed quickly in order to evaluate the liquid physical properties of products containing volatile components. From such a viewpoint, it is preferable to use an apparatus having means capable of leveling the coating liquid, such as a vibration roll (film thickness control roll in FIG. 1).

  The means for leveling the coating liquid does not necessarily need to be a roll as long as the effect is exhibited. For example, the roll can be replaced with a blade, a film, or the like.

  The measurement is performed by loading a predetermined amount of sample on the driving roll. However, due to the reasons already described, care must be taken when setting the sample amount.

The roll rotation speed is preferably set lower than that for normal use in ink evaluation, more preferably 50 to 400 rpm, and particularly preferably 50 to 200 rpm. This is because mascara is high in the volatile component ratio and is quickly dried on a roll. For example, in the case of the incometer roll diameter used in the examples, the printing ink is usually measured at a rotational speed of 400 to 1200 rpm, but the mascara evaluation is performed under the above conditions to prevent sample misting. In addition, rapid liquid drying due to high-speed rotation can be avoided and results with good reproducibility can be obtained.
If this method is used, it is possible to capture the change in force (tack value) required for evaporating the volatile component, that is, the force required to elongate the liquid accompanying the drying of the liquid along the time axis (FIG. 2).

  For example, when tack values were measured for four types of mascara samples with different styling performance of eyelashes, mascara with excellent styling performance showed a high value at the peak of the tack value, and this value was clearly lower for mascara with insufficient performance. It can be seen that the tack value is an important physical property factor for imparting styling performance to the mascara product, and is an index that can be used as an objective evaluation value for this performance (FIG. 3).

  Examples of mascara performance that can be evaluated in the method of the present invention include eyelash styling performance and coloring performance. The method of the present invention is particularly suitable for evaluation of eyelash styling performance. Here, the styling performance of eyelashes means the performance of giving a desired shape to the eyelashes using a brush when applying mascara.

In this way, by obtaining the “force required to extend the liquid”, it is possible to objectively evaluate the performance of mascara such as styling performance and to easily inspect changes in performance during manufacturing and storage. Product quality control becomes possible.
Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
The tack value of the mascara sample was measured using a digital incometer (model D) manufactured by Toyo Seiki Seisakusho. Mascara samples were formulated on a water / ethanol basis and compared for those containing 9% ethanol (91% water) (Sample A) and those containing 15% (85% water) (Sample B). Other ingredients such as colorants remain the same. The driving roll rotation speed was set to 100 rpm and the roll surface temperature was set to 30 ° C. Moreover, the measurement room temperature was 22 degreeC and the humidity 60%. The amount of sample used is 0.7 cc. Drive roll (metal roll) diameter 76.2 mm (length about 16 cm), free rotation roll (top roll: rubber roll) diameter 79.3 mm (length about 16 cm), vibration roll (rubber roll) diameter 50.8 mm (length about) 18.5 cm). The results are shown in FIG.

  From this, it can be seen that the elongation property evaluation value (tack value) of the mascara sample changes with the volatilization of the volatile component. The strength of the extended physical properties rises from a low state before the volatilization of the medium as the volatilization proceeds, attenuates by giving a peak, and goes to a steady value after the volatilization. In a sample containing a large amount of ethanol and having a fast volatilization, the peak value of the extended physical properties appeared in a shorter time. Therefore, if this method is used, it is possible to evaluate changes in physical properties during the volatilization process of the product. This physical property change is related to the quantity ratio of volatile components as in the above example, and is also considered to be related to the dispersion state of the powder and the quality of the contained polymer raw material. It can be used as an effective index for detecting shakes related to these factors above.

Example 2
In the same manner as in Example 1, four types of mascara samples having different eyelash styling performances were measured. As a result of an actual use evaluation by the paneler, when the sample C is used as a reference, the sample D is superior to the above performance, and the sample E is further superior to these performances and the above performance is the best. On the other hand, the performance of the sample F is insufficient. The results are shown in FIG.

  From the results of FIG. 3, it can be seen that mascara excellent in styling performance for eyelashes exhibits a high value at the peak of the elongation property evaluation value (tack value). On the other hand, this value was clearly lower in mascara with insufficient performance. Moreover, it turned out that the coloring performance (attachment amount to the eyelash of a mascara) with respect to eyelashes is also the same order. From these results, it can be seen that the value at the peak of the extended physical property evaluation value is an important physical property factor for imparting the above performance to the mascara product, and is an index that can be used as an objective evaluation value for this performance.

FIG. 1 is a conceptual diagram of an incometer. FIG. 2 is a diagram showing changes in the evaluation value (tack value) of the extended physical properties during the drying process for two types of mascara having different volatilization rates. FIG. 3 is a diagram showing changes in the evaluation value of elongation property (tack value) in the drying process for four types of mascara having different styling performances for eyelashes.

Claims (2)

  A plane including both roll axes generated when the liquid splits at least between the nip formed by the two rolls of the drive roll and the free-rotation or synchronous-rotation roll, as the force required to extend the liquid A method for evaluating the performance of a mascara, characterized by measuring a force required to elongate a liquid which is a force perpendicular to the surface.   A plane including both roll axes generated when the liquid splits at least between the nip formed by the two rolls of the drive roll and the free-rotation or synchronous-rotation roll, as the force required to extend the liquid A method for quality control of mascara, characterized by measuring a force required to elongate a liquid which is a force perpendicular to the surface.

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