KR102394660B1 - Method of Measuring Hair Elasticity - Google Patents

Abstract

The present invention relates to a method for measuring hair elasticity, and more particularly, to a method for measuring hair elasticity using an angle at which the hair is inclined from a horizontal surface by gravity, a vertical distance from the horizontal surface, and the weight of the hair by fixing one end of the hair to a vertical surface. it's about According to the method for measuring hair elasticity of the present invention, compared with the conventional method in which the elasticity of hair is qualitatively compared and evaluated only at the angle at which the hair is inclined with respect to the vertical plane, the weight of the hair and the vertical distance at which the hair is inclined are considered. Since the elasticity of is calculated through the equation, accurate quantitative values can be compared and analyzed. In addition, compared to the conventional method in which a large amount of hair samples had to be measured several times in order to increase the reliability in the results of the stress-strain curve, the present invention calculates a quantitative value through an equation, thereby reducing the time and effort required. It has a mitigating effect.

Description

Method of Measuring Hair Elasticity

The present invention relates to a method for measuring hair elasticity, and more particularly, to a method for measuring hair elasticity using an angle at which the hair is inclined from a horizontal surface by gravity, a vertical distance from the horizontal surface, and the weight of the hair by fixing one end of the hair to a vertical surface. it's about

It is known that hair is damaged by friction, heat, physical cutting, perm, bleaching, dyeing, sunlight, and the like. First, in the case of hair damage due to heat, the moisture evaporates and dries due to the heat generated in the dryer during drying after washing the hair, causing the hair to expand and deform, and the black hair is discolored to dark brown. In addition, bubbles begin to form in the cortex and medulla of the hair, the hair loses elasticity, and the hair epidermis melts. Second, hair damage caused by perm is caused by poor treatment of perm solution and lack of time left unattended. do. Third, as a decolorizing agent, in addition to an alkali agent, the oxidative decolorization action of melanin pigment by hydrogen peroxide occurs. Repeated exposure to bleaching agents in the short term causes repeated swelling and softening of the hair, or twisting and bending of the hair epidermis, which can cause damage. Finally, the keratin protein of the hair is damaged or the protein is denatured by infrared rays and ultraviolet rays among sunlight.

In general, hair is composed of keratin protein containing 14 to 18% cysteine out of 18 amino acids. These keratin proteins are a kind of very strong protein under mild conditions such as water or a neutral solvent, but can be easily damaged by excessive physicochemical treatments such as combing, drying heat, dyeing, perming, and the like. Recently, hair is damaged by various physical, chemical or environmental factors such as frequent perm and dyeing, which makes the hair rough, loses gloss, and loses flexibility. In addition to the problems of the back, the hair becomes thin and loses elasticity, and there is a problem that the volume is lost as it becomes lifeless and sagging.

In order to solve these problems, continuous research has been conducted on products for improving the flexibility of hair during or after washing, and for restoring and strengthening damaged hair, and various methods have been tried, developed, and put to practical use. However, prior to developing a product to be applied to hair, there is no way to quantitatively and accurately quantify the gloss, flexibility, and elasticity of hair.

Accordingly, the present inventors have completed the present invention by focusing on the method for measuring the elasticity of hair based on Hooke's law, which is a physical law relating to the force and deformation degree of the elastic body to its original state.

Korean Patent Publication No. 2013-0031670 "Method for measuring hair adsorption amount of silicone in cosmetic composition for hair using XRF"

Conventionally, a method for measuring the elasticity of hair is as follows. First, both ends of the hair are fixed in a tensile strength measuring device with a holder, and then tension is applied to obtain a stress-strain curve result, and the elasticity (N/m) is obtained from this curve result. Although this measurement method can obtain tensile results and elasticity results quantitatively at the same time, it cannot take into account variables related to mass, thickness and length of hair. . In addition, it is difficult to fix the hair to the tension measuring device holder, and since it takes a relatively long measurement time, there is a problem that it takes a long time to measure the hair several times with a large amount of hair samples.

An object of the present invention is to derive the elasticity of hair as a quantitative numerical value, and another object of the present invention is to increase the reliability of the result more easily by deriving an accurate measurement value while reducing the number of experiments.

The present invention has been devised to solve the above problem, and by fixing one end of the hair to a vertical plane, the hair is tilted from the horizontal plane by gravity, the vertical distance from the horizontal plane, and the weight of the hair to measure the elasticity of the hair provides a way to

More specifically, i) fixing one end of the hair at a right angle to the vertical surface; ii) tilting the hair from a horizontal plane by gravity; iii) drawing a first tangent line at one end to which the hair is fixed and a second tangent line at the other end of the hair; iv) drawing a perpendicular (perpendicular) from the point where the extension line of the first tangent line and the extension line of the second tangent line meet each other to the hair; v) measuring the vertical distance (y, meters (m)) from the foot of the waterline to the horizontal plane; vi) drawing a straight line from the foot of the repairman to one end to which the hair is fixed; and vi) measuring the angle (θ, degree (˚)) formed between the straight line and the horizontal plane (H), and the degree of elasticity (k, elastic modulus (N/m) of the hair by Equation 2 below )) to measure the elasticity of the hair.

Equation 2) ky = mg sin (90˚-θ)

(However, m is the mass of hair (kg), g is the acceleration due to gravity (m/sec ² ))

According to the method for measuring hair elasticity of the present invention, compared with the conventional method in which the elasticity of hair is qualitatively compared and evaluated only at the angle at which the hair is inclined with respect to the vertical plane, the weight of the hair and the vertical distance at which the hair is inclined are considered. By calculating the elasticity of , it is possible to compare and analyze accurate quantitative values.

In addition, compared to the conventional method in which a large amount of hair samples had to be measured several times in order to increase reliability in the results of the stress-strain curve, the present invention calculates a quantitative value through an equation, thereby reducing the required time and It has the effect of reducing the effort.

1 is an image of a method for measuring the elasticity of hair in the prior art.
2 is a conceptual diagram of a method for measuring the elasticity of hair according to the present invention.
3 is a conceptual diagram for applying a trigonometric function in the method of measuring the elasticity of hair of the present invention.
4 is a working image of fixing hair to a vertical surface in order to measure the elasticity of the hair as an embodiment of the present invention.
5 is a working image imaged with a camera in order to measure the elasticity of hair as an embodiment of the present invention.
6 is a working image of applying the method of measuring the elasticity of hair of the present invention to an image imaged with a camera as an embodiment of the present invention.
7 is a normal distribution curve of results derived through a method of measuring hair elasticity as an embodiment of the present invention.

The present invention relates to a method for measuring hair elasticity, and more particularly, by fixing one end of the hair to a vertical surface, and measuring the hair elasticity using the angle at which the hair is inclined from the horizontal surface due to gravity, the vertical distance from the horizontal surface, and the weight of the hair. It's about how to measure.

If you hang a weight on the spring, you can see that the spring stretches according to the weight of the weight. As such, the degree of deformation of the elastic body including the spring is proportional to the force to restore to its original shape, that is, the elastic force. In this regard, Hooke's law is a law that the degree of deformation (x) of an elastic body by an external force (mg) is directly proportional to the elastic force (F _{elastic force} ) to be restored to its original state within a certain external force range. It is expressed by Equation 1). In the present invention, in order to quantitatively derive the elasticity of hair, Hooke's law applied to the elastic body is applied.

Equation 1) kx = mg

(However, m is the mass of hair (kg), g is the acceleration due to gravity (m/sec ² ))

In the present invention or in the present specification, the 'elasticity' or 'elasticity' of hair is a characteristic of hair that the hair wants to support straight from the scalp surface at a right angle, and is related to 'k (Stiffness)', which is the modulus of elasticity in Hooke's law. It is different from the F _elastic force, which is a restoring force that acts in the opposite direction of gravity to keep the hair at a right angle from the scalp surface. Therefore, the present invention is to measure the elasticity (elasticity) of hair by calculating the elastic modulus 'k' of Hooke's law.

In addition, in the present invention or the present specification, the mass (m) or weight (mg) of the hair is a comprehensive concept including a mass or weight that is increased than the mass of the actual hair itself due to the remaining components of the product applied to the sample to be tested.

In addition, each numerical value applied to the present invention or the equations in this specification follows the SI basic unit system, which is an international standard unit.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments of the present invention and the accompanying drawings. Meanwhile, in order to clarify the present invention, content not related to the configuration of the present invention will be omitted, but the same reference numerals in the drawings will be described on the assumption that the same elements are referred to.

In the prior art, as shown in FIG. 1 , the degree of hair elasticity was predicted by measuring only the angle at which the hair was tilted while fixing one end of the hair to the vertical surface, and thus, quantitative results of hair elasticity could not be presented. However, the present invention proposes a method of measuring the elasticity of hair by measuring not only the inclined angle of the hair, but also the vertical distance away from the horizontal plane and the weight of the hair, and applying the modified Hook's Law.

When the method for measuring hair elasticity of the present invention is described in more detail with reference to FIG. 2 , first, when one end (a) of the hair is fixed at a right angle to the vertical plane (V), the other end (b) of the unfixed hair is caused by gravity. As it falls, the hair is inclined with respect to the horizontal plane (H). After drawing a first tangent line at one end (a) of the fixed hair in this inclined state, and a second tangent line at the other end (b) of the drooping hair, the point (o) where their extension lines meet each other is determined Draw a perpendicular to When the repair's foot (p) is determined in this way, the shortest distance from this point to the horizontal plane (H), ie, the vertical distance (y), is measured in meters (m), and the hair from the repair's foot (p) is A straight line is drawn up to the fixed end (a), and the angle (θ, (degree)) formed by this straight line and the horizontal plane H is measured. By applying this to the following Equation 2) of the present invention conceived from Hooke's law, the degree of elasticity (k, elastic modulus (N/m)) of the hair is quantitatively calculated.

Equation 2) ky = mg sin (90˚-θ)

(However, m is the mass of hair (kg), g is the acceleration due to gravity (m/sec ² ))

As an embodiment of the present invention, in order to measure the elasticity of the hair, the vertical distance from the point (p) at the point (o) where the extension lines of the first tangent line (A) and the second tangent line (B) meet each other ( y) is determined, but this is a measure of how far the hair is from the horizontal plane H due to gravity, and any point can be determined as long as the distance between the hairs to be measured can be objectively compared. For example, in the present invention, the vertical distance 'y' may be a vertical distance from the midpoint (1/2 ab) of the total hair length ab to the horizontal plane H.

3 is to explain the reason that Equation 1) for measuring the elasticity of hair of the present invention is modified from Hooke's law, assuming that the vertical plane V of FIG. 2 is the surface of the scalp and the line segment ap is the hair When this is done, since the hair ap to maintain a perpendicular state from the surface V of the scalp is inclined by 'θ' by gravity, the angle between the surface V of the scalp and the hair ap is '90 It becomes ˚-θ'. In order to apply the Hooke's law to the method of measuring hair elasticity, the present invention introduces a sin function, and as the elasticity of the hair is excellent, 90˚-θ is closer to 90˚, that is, as θ converges to 0˚, sin (90˚-θ) ≒ 1. Conversely, if the elasticity is low and 90˚-θ is close to 0˚, that is, as θ converges to 90˚, sin(90˚-θ) ≒ 0.

In order to verify the method for measuring hair elasticity of the present invention, the procedure of <Example 1> was performed.

<Example 1>

Standard hair (manufacturer: Japan) Beaulax Inc. ) preparation

Since the company manufactures various types of hair (actual human hair) according to standard standards, the standard hair used in this experiment can be applied as an alternative to actual human hair.

Set the number of hairs required for one measurement

For measuring hair elasticity of the present invention, one single strand or two to five multiple strands of hair can be used as a sample. It is preferable to carry out Hereinafter, a hair elasticity measurement test was performed with three plural strands in order to match the conditions of human hair.

Elasticity measurement

4 to 5 are one embodiment of the present invention, and as shown in FIG. 4, one end of the three hairs is fixed at a right angle to a wall, which is a vertical plane, so that the hair is moved from the horizontal plane (H) by gravity. make it tilt As shown in FIG. 5, this state is imaged with a camera. As shown in FIG. 6 based on the image imaged in this way, a first tangent line is drawn from the starting point where the hair is fixed, and a second tangent line is drawn from the other end where the hair is not fixed to determine the point where the extension lines of each tangent line meet each other . From this point, the vertical distance (y) from this point to the horizontal plane at the point where the hair is fixed is measured, and from this point, the point where the hair is fixed is determined. The angle (θ) formed by the straight line and the horizontal plane at the point where the hair is fixed is measured by connecting the point to the point.

The measured results are as follows.

y = 0.01 m

θ = 30˚

m = 0.0000016 kg

Based on the measurement result, the elasticity (k) of the hair is obtained by applying Equation 2).

k = 0.167 mN/m

Meanwhile, the process of increasing hair elasticity is as follows. To increase the elasticity of the hair, it is treated with an elasticity enhancing product (such as a firming shampoo). Due to this, the effective ingredients in the product penetrate and adsorb to the inside/outside of the hair, increasing the elasticity of the hair, and the effective ingredients of the product are applied to the hair on the scalp surface. It will help you to hold it close to a right angle. The following is a hair elasticity product, and a test was conducted according to <Example 2> to measure the degree of hair elasticity before and after the company's hair elasticity enhancing shampoo treatment.

<Example 2>

To measure the elasticity (k) according to the mass (m) or weight (mg) of the hair, water-treated hair (control group), hair treated with hair elasticity enhancing shampoo once (Experimental group 1), and hair treated with hair elasticity enhancing shampoo twice ( Using the experimental group 2) as a sample, the degree of elasticity was measured by the method for measuring hair elasticity.

[Table 1]

validation

7 is a normal distribution curve confirming the results of the elasticity (k) value of Example 2 through repeated experiments several times. It can be seen that experimental groups 1 and 2 treated with the elasticity enhancing shampoo increased the elasticity of the hair compared to the control group, and it was verified that the quantitative value of elasticity can be derived within the error range through about 20 experiments.

Even if the hair is obtained from the same tress or from a single person, the thickness, length, and shape are very different. Since the elasticity value is affected by the shape of the hair, the result of one elasticity measurement test cannot define a sample. Therefore, a large number of measurements are required and the statistically normal distribution curve must be satisfied. It was confirmed that the method for measuring hair elasticity of the present invention satisfies the normal distribution curve with 20 experiments per one hair sample.

V. vertical plane
H. horizontal plane
A. First tangent
B. Second tangent
y. The vertical distance at which the hair is inclined from the horizontal plane
θ. The angle at which the hair is inclined from the horizontal plane

Claims (4)

A method of measuring hair elasticity using an angle (θ) at which one end of the hair is fixed to the vertical plane (V) and the hair is inclined from the horizontal plane (H) by gravity and the vertical distance (y) from the horizontal plane (H),
i) fixing one end (a) of the hair at a right angle to the vertical plane (V);
ii) the hair is inclined from the horizontal plane (H) by gravity;
iii) drawing a first tangent line (A) at one end (a) to which the hair is fixed and a second tangent line (B) at the other end (b) of the hair;
iv) drawing a perpendicular (Perpendicular) from the point (o) where the extension line of the first tangent line (A) and the extension line of the second tangent line (B) meet each other;
v) measuring a vertical distance (y, in meters (m)) from the foot (p) of the waterline to the horizontal plane (H);
vi) drawing a straight line from the foot of the repair man (p) to the one end (a) to which the hair is fixed; and
vi) measuring the angle (θ, degree (˚)) formed by the straight line and the horizontal plane (H);
A method of measuring hair elasticity comprising a.
delete According to claim 1,
viii) calculating the degree of elasticity (k, elastic modulus (N/m)) of the hair according to Equation 2 below;
Hair elasticity measurement method further comprising;

Equation 2) ky = mg sin (90˚-θ)
(However, k is the elasticity of the hair, m is the mass of hair (kg), g is the acceleration due to gravity (m/sec ² ), and y and θ follow the definition of claim 1)
According to claim 1,
The method of measuring hair elasticity, characterized in that the hair is one single strand or 2 to 5 multiple strands.

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