Method for analyzing degree of hydrophobicity of powder, highly hydrophobized coloring pigment, and cosmetic containing said coloring pigment

Patent metadata

Field	Value
Publication number	US-2020132579-A1
Application number	US-201816616254-A
Country	US
Kind code	A1
Filing date	May 23, 2018
Priority date	May 25, 2017
Publication date	Apr 30, 2020
Grant date	—

Abstract

The present invention addresses the problem of evaluating the hydrophobicity of a powder. According to the present invention, a powder is charged into a mixed solvent composed of a lipophilic solvent and a hydrophilic solvent, the voltage rate R of the mixed solvent is measured at predetermined time intervals while adding a lipophilic solvent to the mixed solvent charged with the powder, a parameter x correlating with the concentration of powder is defined for an arbitrary voltage rate R, a continuous function HP(x) of the ratio of a lipophilic solvent corresponding to x is defined, and HP(x) for required x is set as a representative value of a lipophilic solvent ratio distribution and used as an index of hydrophobicity.

First claim

1 . A method for analyzing the degree of hydrophobicity of a powder,
adding a powder to be evaluated for its degree of hydrophobicity to a solvent mixture of a lipophilic solvent and a hydrophilic solvent, continuously adding the lipophilic solvent to the solvent mixture having the powder added thereto, measuring a voltage rate of the solvent mixture at predetermined time intervals, at least until the voltage rate reaches the minimum, provided that for data discrete values as measured, the voltage rate observed relative to time series t i (wherein i is an integer, t i <t i+1 ) is R i , the maximum of voltage rate is 100, and the minimum of voltage rate is R min , a parameter correlating to a powder concentration relative to an arbitrary voltage rate R in the range: R min <R<100 is defined as

x
=

100
-
R

100
-

R
min

×
100




(

wherein



0

<
x
<
100

)

,

[

Math
.


1

]

a lipophilic solvent ratio in the solvent mixture corresponding to that x is represented by HP(x), a continuous function HP(x) of lipophilic solvent ratio is defined, for R meeting the range: R i+1 ≤R<R i wherein i is an integer, as

HP


(
x
)

=

HP

i
+
1

-

HP
i

R

i
+
1

-

R
i

×

(

R
-

R
i

)

+

HP
i

,

[

Math
.


25

]

and the parameter x (wherein 0<x<100) changes in proportion to a powder concentration c(t) (wherein 0<c(t)<c max ) or cumulative sedimentation weight W(t) (wherein 0<W(t)<W max ), computing HP(x) at a preselected value of x as a representative value of the lipophilic solvent ratio distribution, the HP(x) being regarded as an index of hydrophobicity.

2 . The analysis method of claim 1 wherein for the voltage rate R i observed relative to time series t i , measurement data at total (2n+1) points (wherein n is an integer) including a certain point and fore and aft n points are averaged, a value obtained by smoothening according to the equation:

R
_

i

=

∑

i
=

-
n

n



R
i

[

Math
.


3

]

is used as the voltage rate, the maximum of voltage rate is 100, and the minimum of averaged voltage rate is
R min ,  [Math. 4]

a parameter correlating to a powder concentration with respect to an arbitrary voltage rate R in the range:
R min < R< 10 C   [Math. 5]

is defined as

Assignees

• Shinetsu Chemical Co

Inventors

• Inukai Tetsuya
• Saito Mitsugu
• Okawa Tomoki
• Kamei Masanao
• Moriya Hiroyuki
• Hayakawa Chihiro
• Kikuchi Hiroko
• Inaba Ryuichi

Classifications

• C09C3/12

  Treatment with organosilicon compounds {(C09C3/006 takes precedence)} · CPC title

• A61Q1/10

  for eyes, e.g. eyeliner, mascara · CPC title

• C09C1/24

  Oxides of iron · CPC title

• A61K8/06

  Emulsions · CPC title

• A61K8/29

  Titanium; Compounds thereof · CPC title