Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Patent
1990-03-16
1990-11-27
Raevis, Robert
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
G01D 702
Patent
active
049727184
ABSTRACT:
The condition of hair or other keratin fibers can be evaluated by measuring the force required to obtain a first value of elongation of the fiber in the yield region of the force-elongation curve, and the force required to obtain a second value of elongation of the fiber in the yield region. The ratio of these two measured forces is then determined as a damage index for the fiber. It is found that a constant force ratio is obtained for wet virgin keratin fiber independent of fiber diameter or the source of the fiber. It is also found that the force ratio changes as a function of subjective or objective measures of chemical damage to the hair fiber. The force ratio or damage index can, therefore, be used for identifying hair care products suitable for application to the hair without inducing unacceptable damage. The tests may be performed with simple tensile testing apparatus without tedious examination of the hair under a microscope.
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patent: 4628742 (1986-12-01), Golding
patent: 4635654 (1987-01-01), Mathews et al.
Edman, et al., "Properties of Peroxide-Bleached Hair", J. Soc. Cosmet Chem, vol. 12(3); 133-145 (1961).
Jachowicz, "Hair Damage and Attempts to Its Repair", J. Soc. Cosmet. Chem., 38, 263-286 (July/Aug. 1987).
Wolfram, et al., "The Mechanism of Hair Bleaching", J. Soc. Cosmet Chem, 21, 875-900 (Dec. 9, 1970).
Robbins, "Physical Properties and Cosmetic Behavior of Hair", Springer, Verlag. 1988.
Hunter Leroy D.
Mathews Roger A.
Said Hayel M.
Raevis Robert
Redken Laboratories Inc.
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