| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for measuring acutely, easily and correctly in a quantitative state a hair damage degree due to a chemical treatment agent.SOLUTION: A method for evaluating a hair damage degree of a subject in a quantitative state, is configured so that: a hysteresis ratio on a hysteresis curve indicating a relationship between skewness and stress, in which the relationship is acquired by measurement of the stress of hair when tension is applied to the hair and the hair is extended at constant speed for applying the skewness which is X% of original length of the hair, and the hair is returned to original length at the same speed, a stress ratio on a conversion point of linear change of two compatibilities during extension of the hysteresis curve and/or curvature of the curve of the hysteresis curve during extension, are used as indexes, therefore the hair damage degree of the subject is evaluated, with hair which is not treated by a chemical treatment agent, as reference. A device for using the same method is also provided. |
