Assessment of damage in keratin fibers
First Claim
1. A method for analyzing keratin fiber comprising the steps of:
- measuring a first force required to obtain a first value of elongation of a keratin fiber, wherein the first force is less than the force required to reach the break point elongation region of the force-elongation curve;
measuring a second force required to obtain a second, relatively higher, value of elongation of a keratin fiber wherein the second force is less than the force required to reach the break point elongation region of the force-elongation curve;
determining a force ratio of the second force and the first force;
determining a representation of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and
determining at least one analysis factor that is directly proportional to a nonlinear mathematical function of the force ratio and the representation of fiber elongation.
1 Assignment
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Accused Products
Abstract
Keratin fiber condition is evaluated by testing dry hair to determine analysis factors. For each factor, two values of elongation are determined by measuring the force required to obtain a first value and a second value of elongation of the fiber. The percent total elongation of the fiber to its break point is also determined. The ratio of the two measured forces is used with the percent total elongation in empirically derived nonlinear equations to determine analysis factors, such as a condition factor and a moisture factor. It is found that each factor is independent of fiber diameter or the source of the fiber. It is also found that the factors change as a function of subjective or objective measures of chemical damage to, and moisture content of, the hair fiber. The factors 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. Additionally, the hair diameter can be determined by wedging fiber clamps used in the test apparatus.
38 Citations
44 Claims
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1. A method for analyzing keratin fiber comprising the steps of:
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measuring a first force required to obtain a first value of elongation of a keratin fiber, wherein the first force is less than the force required to reach the break point elongation region of the force-elongation curve; measuring a second force required to obtain a second, relatively higher, value of elongation of a keratin fiber wherein the second force is less than the force required to reach the break point elongation region of the force-elongation curve; determining a force ratio of the second force and the first force; determining a representation of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is directly proportional to a nonlinear mathematical function of the force ratio and the representation of fiber elongation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for analyzing keratin fiber comprising the steps of:
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measuring a first force required to obtain a first value of elongation of a keratin fiber, wherein the first force is less than the force required to reach the break point elongation region of the force-elongation curve; measuring a second force required to obtain a second, relatively higher, value of elongation of a keratin fiber wherein the second force is less than the force required to reach the break point elongation region of the force-elongation curve; determining a force ratio of the second force and the first force; determining a representation of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is a measure of moisture content of a keratin fiber that is directly proportional to the mathematical product of the representation of fiber elongation and the logarithm of the force ratio.
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11. A method for analyzing keratin fiber comprising the steps of:
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measuring a first force required to obtain a first value of elongation of a keratin fiber, wherein the first force is less than the force required to reach the break point elongation region of the force-elongation curve; measuring a second force required to obtain a second, relatively higher, value of elongation of a keratin fiber wherein the second force is less than the force required to reach the break point elongation region of the force-elongation curve; determining a force ratio of the second force and the first force; determining a representation of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is a measure of cysteic acid content of a keratin fiber that is directly proportional to the mathematical product of the logarithm of the representation of fiber elongation and the square of the force ratio.
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12. A method for evaluating the condition of hair comprising the steps of:
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measuring the force required to elongate a strand of hair a first percentage of its length; measuring the force required to elongate the strand of hair a second percentage of its length; determining a force ratio between the first and second forces; determining a measure of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is proportional to the force ratio and the measure of fiber elongation at the break point of the fiber, wherein the proportionality is to the logarithm of the measure of fiber elongation to the break point of the fiber. - View Dependent Claims (13, 14)
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15. A method for evaluating the condition of hair comprising the steps of:
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measuring the force required to elongate a strand of hair a first percentage of its length; measuring the force required to elongate the strand of hair a second percentage of its length; determining a force ratio between the first and second forces; determining a measure of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is proportional to the force ratio and the measure of fiber elongation at the break point of the fiber, wherein the proportionality is to the logarithm of the force ratio. - View Dependent Claims (16, 17)
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18. A method for evaluating the condition of hair comprising the steps of:
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measuring the force required to elongate a strand of hair a first percentage of its length; measuring the force required to elongate the strand of hair a second percentage of its length; determining a force ratio between the first and second forces; determining a measure of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; and determining at least one analysis factor that is proportional to the force ratio and the measure of fiber elongation at the break point of the fiber, wherein the proportionality is to the square of the force ratio.
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19. A method for evaluating the condition of hair comprising the steps of:
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measuring the force required to elongate a strand of hair a first percentage of its length; measuring the force required to elongate the strand of hair a second percentage of its length; determining a force ratio between the first and second forces; determining a measure of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; determining at least one analysis factor that is proportional to the force ratio and the measure of fiber elongation at the break point of the fiber; and determining the moisture content of a keratin fiber as a function of the determined analysis factor. - View Dependent Claims (20, 21)
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22. Apparatus for assessing condition of a keratin fiber comprising:
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means for applying an elongating force to a keratin fiber; means connected to the means for applying force, for determining a ratio of forces required to obtain each of two selected values of elongation of the keratin fiber within the range defined by the yield and post-yield regions of the force-elongation curve for the fiber; means connected to the means for applying force, for determining fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; means for determining the fiber diameter by determining a distance from a means for clamping without a fiber present to the means for clamping with a fiber present, wherein the means for clamping is moved along a line that converges relative to a length of the fiber; means connected to the means for determining a ratio and to the means for determining a quantity of fiber elongation, for determining at least one analysis factor as a function of both the force ratio and the quantity of elongation; and means connected to the means for determining at least one analysis factor, for displaying at least one analysis factor. - View Dependent Claims (23, 24, 25)
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26. Apparatus for evaluating condition of hair comprising:
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means for elongating a hair fiber; means connected to the means for elongating, for measuring force applied to the fiber at each of first and second selected elongations; means connected to the means for measuring, for determining the ratio of the first and second forces; means connected to the means for elongating, for determining an assessment of fiber elongation that occurs as measured from substantially no elongation to a break point of the fiber; means connected to the means for determining a ratio and to the means for determining an assessment of fiber elongation, for determining at least one analysis factor that is proportionally related to a nonlinear equation of the force ratio and the assessment of fiber elongation; and means connected to the means for determining at least one analysis factor, for displaying at least one analysis factor. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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33. A method for analysis of keratin fibers comprising:
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determining a fiber "condition factor," designated Fc, according to the following equation;
space="preserve" listing-type="equation">F.sub.c =Logarithm E.sub.B ×
(F.sub.2 /F.sub.1).sup.2 ;wherein EB is a measured elongation to a break point of the fiber; wherein F1 is a measured force of a first elongation; wherein F2 is a measured force of a second elongation; wherein the Logarithm is a logarithm base 10; and determining the cysteic acid content of a keratin fiber as a function of the determined condition factor.
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34. A method for analysis of keratin fibers comprising:
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determining a fiber "moisture factor," designated Fm, according to the following equation;
space="preserve" listing-type="equation">F.sub.m =E.sub.B ×
Logarithm (F.sub.4 /F.sub.3);wherein EB is a measured elongation to a break point of the fiber; wherein F3 is a measured force of a first elongation; wherein F4 is a measured force of a second elongation; wherein the Logarithm is a logarithm base 10; and determining the moisture content of a keratin fiber as a function of the determined moisture factor. - View Dependent Claims (35, 36)
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37. Apparatus for clamping and determining the diameter of a hair fiber comprising:
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a fixed surface for receiving a hair fiber; a member movable along a path parallel to the length of a fiber on the fixed surface and converging toward the fixed surface for clamping the fiber; means for measuring travel of the movable member in a direction along the length of the fiber; and means for determining the thickness of the fiber as a trigonometric function of travel of the movable member. - View Dependent Claims (38, 39, 40)
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41. A method for measuring hair diameter comprising the steps of:
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placing a hair fiber on a flat surface; moving a member along a path converging toward the flat surface until the member engages the hair fiber and clamps the hair fiber between the member and the flat surface; determining the distance between the locus of the member when engaged with the hair fiber and the locus of the member when engaged with the flat surface; and multiplying the distance by a trigonometric function of the angle of convergence. - View Dependent Claims (42, 43, 44)
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Specification