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Content
E. Bartholomey*
The Use of Ultramarine Pigments in Cosmetics
■■ Introduction
The natural form of the mineral ultramarine blue is, lapis lazuli, but our discussion
focuses upon the synthetic or artificial
varieties of ultramarine pigments as used
in the cosmetic and personal care industries. The term »ultramarine« must have
been in use in Italy by the beginning of
the fourteenth century as Antonio Filarete wrote in 1464 that »Fine blue is derived from a stone and comes from across
the seas and so is called ultramarine« (1).
The ultramarine family of colors includes
blue, green, pink and violet.
The pinks, violets, and greens are weaker colors than blue. However, they are
used in cosmetics and in artist’s paints.
Green is rarely used. The composition of
the ultramarine pigments is very variable and almost never stoichiometric.
(Table 1)
Ultramarine blues are synthetically produced sodium alumino sulpho- silicates.
The major component is a complex sulfur-containing sodium-silicate (Na66-10
Al6Si6O24S2-4) which makes ultramarine
the most complex of all mineral pigments. Some chloride is often present in
the crystal lattice as well. The structure
Abstract
U
ltramarine pigments are used within the cosmetic industry primarily in eye make-up products. Eyeshadows, mascaras and eyeliners,
and concealers may contain ultramarines that display a wide range
of colors. Variants of the ultramarine blue pigment such as »ultramarine
pink«, »ultramarine green«, »ultramarine violet« are known, and are
based on similar chemistry and crystalline structure.
Generally, these pigments are hydrophilic and water-dispersible. Surface
treatments can help to improve the dispersion of ultramarine pigments in
cosmetics oils and esters. The refractive indices of the surrounding media
help to determine the lightness/darkness, opacity, and hue of the pigment. Transparency is increased when the difference in the refractive indices of the pigment and the media are small. Variations of the differences
in refractive indices allow for the creation of new and improved pigment
mixtures. Translucent ultramarine colors can also synergize with special effects pigments to introduce new products to the consumer.
26
Colors
Chemical Composition
Blue
Na7Al6Si6O24S3
Violet
Na6-10Al6Si6O24S2-4
Pink
Na7Al6Si6O24S3
Green
Na6.50Al6.30Si5.70O24S3.5
Table 1 Chemical composition of
ultramarine pigments.
consists of an open three-dimensional
framework of AlO4 and SiO4 tetrahedra
and within this framework are found
small sulfur-containing anions together
with sodium cations which maintain
overall electrical neutrality. There are
two types of sulfur groups in ultramarine blue, (S3−) and (S2−). The blue color
of the pigment is due to the radical anion (S3−) absorbing at (600 nm) and (S2−)
at 380 nm both containing an unpaired
electron (2). This is stabilized within the
alumino-silicate framework.
■■ Manufacture
Different shades of ultramarine blue exist: Cobalt Blue Hue (least violet), Ultramarine Blue (medium violet), and French
Ultramarine Blue (most violet). Every one
of these colors is simply one pigment,
(C. I. Pigment Blue 29: 77007). Variations are due to strength, particle size,
processing conditions, formulation, etc.
The manufacture of ultramarine blue
is described in Patent US 2806802 A »Manufacture of ultramarine blue« (3).
Green ultramarine (or primary ultramarine) is just an intermediate product in
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Content
Fig. 1 Ultramarine pigments blue, violet, and pink surface treated with ITT prior
to grinding.
the synthesis of ultramarine blue. It has
a limited application as a pigment. After
the oxidation process of green ultramarine with atmospheric oxygen at a temperature of about 750° degrees Celsius it
turns to ultramarine blue.
Ultramarine violet’s redness of hue depends
on the degree of oxidation. Oxidation of ultramarine blue or ultramarine green with
air at 130 to 280 °C in the presence of ammonium chloride results in ultramarine violet with the chromophore (S4−). Pink ultramarine (also red ultramarine) is obtained by
processing the violet form with hydrogen
chloride gas in an oxidizing environment
at a temperature of about 150-180 °C or
greater. An ion exchange reaction with
violet produces pink.
The nature of the polysulfide dictates
the color of the solid. In violet ultramarine (C.I. Pigment Violet 15:77007)
and pink ultramarine (C.I. Pigment Red
259:77007) the chromophore is proposed to be S3Cl−, S4− or S4.
Because of their zeolytic structure there is
the potential to create other ultramarine
colors via ion exchange, such as ultramarine yellow and ultramarine white using
soluble salts of metals like silver (yellow),
lithium (blue), manganese (gray), calcium,
potassium (blue), copper, zinc (violet).
Their primary use for cosmetics is in eye
products such as eyeshadows, mascaras,
eyeliners, and in eye pencils. Ultramarine
blue was used significantly in laundry
applications in powder detergents and
soap bars. It improved the whiteness of
white cotton fabrics when washed due
to its ability to adhere to fibers and
absorb yellow wavelengths (4). By absorbing yellow light it creates »whiter
whites«, and in color correction it can
help achieve a match. In greys it can
create subtle blue undertones.
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■■ Optical Properties
The refractive index of ultramarine blue
and similar ultramarine pigments is
1.50-1.54. It has a cubic crystal structure
that is isotropic and exhibits no optical
activity. The hiding power of ultramarine
is greater than would be expected from
its low refractive index.
In aqueous media it will retain a pure
bright blue color due to the difference in
refractive indices. However, in oils where
that difference is minimal it becomes a
much darker blue and translucent. The
dominant wavelength is around 467.8
nm for synthetic ultramarine blue. Ultramarine blue reflects highly in the infrared region and is also used in camouflage
and heat-resisting paints. The oil absorption is between 30 and 40 (g/100g).
■■ Particle Size
The artificial pigment has rounded particles of regular size and shape. Ultramarine blue and green shade particles
are about 0.7-5.0 microns in diameter
and ultramarine red shade particles are
about 5 microns.
Ultramarines are hydrophilic and are
easily dispersed in aqueous media or
polyols. They are easy to grind as a powder. Surface treatments will enhance
the dispersibility of these pigments in
solvents, oils and esters.
■■ Chemical and Physical Properties
Ultramarine pigments have good stability to light. Blue is not affected by
ammonia or caustic alkalies (ph of 7 or
higher) except on very prolonged and
drastic treatment. Pink and violet are not
as stable within the alkali medium as is
blue. Pink is not recommended for toilet
soaps because of this instability (5).
All ultramarines are very readily decomposed by acids. In ultramarine blue,
dilute mineral acids rapidly destroy the
blue color with evolution of hydrogen
sulfide gas. Hydroxonium ions (H3O+) are
small enough to enter the open aluminosilicate framework and react with the
enclosed polysulfide ions.
Acetic acids will attack the pigment
more slowly than mineral acids. So one
must be very cognizant of pH levels in
the lab, during process scale-up and in
manufacturing. Testing long term stability can also reveal changes in the pH. Acid-resistant grades are available in which
the particles are coated with silica or
silicic acid. They are not completely resistant to mild acids, but are more so than
the untreated versions. Grinding these
pigments will reduce the effectiveness
of the silica surface treatment.
Cosmetic surface treatments, such as ITT
and silane, will render the ultramarine
pigments more dispersible and stable in
liquid media. Surface treatments also
improve the application of these pigments onto lashes, the eyelid, under eye
area, and skin in general.
The ultramarine pigments are not permitted in lipsticks, lip glosses or similar
cosmetics where there may be some ingestion even though their overall toxicity is low. They are FDA approved for
food packaging and other uses, but not
for coloring edible foods.
■■ Experimental Data & Results
Transparency is an advantage for ultramarine pigments when they are combined with effect pigments. You can
achieve a combination that can take
advantage of the unique hue of ultramarines, as well as their transparency.
The blue, violet, and pink ultramarines
are excellent for combining with interference pigments, especially in liquid
mediums where their refractive indices
(R.I.) can be fully optimized.
Some pigments that are newer materials
to the industry can synergize well with
ultramarines, such as borosilicate flakes
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or synthetic mica that contain multilayers to promote color travel. The interference colors from these pigments are
extremely chromatic, with higher transparency, sparkle and clarity due to the
substrate and multi-layer design. Many
possibilities exist for using the ultramarine series of pigments with these more
transparent effect pigments.
Content
In order to better understand the ultramarine pigments and their relationship with
liquids of varying refractive indices, we set
up experiments to measure their transparency and shade differences. We created
dispersions using three mediums with a
wide difference in R.I. range. (Fig. 2)
Dispersions of ultramarines are made
at a 50-60 % concentration by leading
manufacturers. We designed the test
to measure the lightness/darkness and
transparency properties of ultramarine
pigments by surrounding the particles
with liquids having different refractive
indices. For the liquids we selected water
(R.I.=1.33), isoamyl laurate (R.I.= 1.44;
Radia 7750) and octyl methoxycinnamate (R.I.=1.54; Escalol 557).
A small amount of dispersant, 2 % polyglyceryl polyricinoleate (Radiamuls Poly
2253), was added to each of the esters.
We added 2 % Lecithin Solec F to the
aqueous dispersion along with a small
amount of triethanolamine to adjust the
pH to the alkaline side.
The ultramarine pigments were surface-treated for the oleophilic systems
with isopropyl titanium triisostearate
to make them more dispersible at high
concentrations. The pigments for the
aqueous system were used without a
coating.
■■ Transparency/Opacity
Fig. 2 Transparency of ultramarine pigments in refractive index media
(dispersions). (Photographs taken at 0.8X magnification.)
28
The overall concentration and transparency/opacity value of the pigments is
important for delivering the unique benefits to the consumer. By creating a more
transparent or translucent film through
the matching of refractive indices, some
light is able to pass through some of
the particles more easily allowing other
surfaces to interplay for complex color
effects.
The transparency of pigments increases
with the following properties: lower refractive index, fineness (until optimal
size is reached), lightness of color and in
certain cases the topography and complexity of the pigment.
We measured the contrast ratio (Black
Y/White Y) which translates to transparency/opacity (Fig. 3). As illustrated
in the graph for contrast ratios, the series of pigments dispersed in the ester,
octyl methoxycinnamate, which has a
closely matching refractive index to
the pigment provides the most transparency. Water has the lowest refractive index and is most distant from
the R.I. of the pigments and therefore
provides the most opacity since more
light is reflected from the surface of
the pigment.
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Content
but not too much chalkiness since its R.I.
value is not too distant from the primary
blue pigment.
The waterproof mascara formulation
makes use of ultramarine blue and
ultramarine violet along with a small
amount of black iron oxide to provide
a deep rich blue color with a slight
tinge of red. The polymer, hydrogenated polycyclopentadiene, has a high
refractive index of 1.55-1.57 which is
very close again to that of the ultramarine pigments. This medium provides
depth of color because the polymer
concentration is significant and helps
to surround the ultramarine pigment
creating a more optimal interface for a
darker shade.
Fig. 3 Measurements of contrast ratios for determining transparency and opacity
in selected mediums.
The isoamyl laurate has an R.I. that is more
or less equidistant from the water and
octyl methoxycinnamate. The pigments
show a balance of transparency and
opacity when combined with this ester.
ing ultramarine pigments in cosmetic
products. The eyeshadow derives its
color primarily from ultramarine blue
and uses pentaerythritol tetraoctanoate
which has a relatively high refractive index of 1.464. This provides good opacity,
■■ Conclusion
Though ultramarine pigments remain
a small segment of the global market
for pigments (<0.5 %) they are widely used within the cosmetic industry.
These colors continue to have potential when used in novel ways, especially
with newer materials that are available.
Surface-treatments and dispersions of
ultramarines enable cosmetic formula-
■■ Lightness/Darkness
The graph for lightness & darkness
above shows the relationship between
the ultramarine pigments and their
ability to appear either light or dark
in surrounding media (Fig. 4). The pigments are very dark in the bulk dispersion in the octyl methoxycinnamate as
light is not reflected from the pigment
interface as it is in aqueous vehicles.
The ultramarine pigments are lighter
and brighter when dispersed in aqueous media as the light gets reflected at
the interface of the pigment and liquid. Again, the isoamyl laurate creates
a nice balance between the two extreme refractive indices and provides
a balance of benefits.
■■ Formulations
Formulation 1 and 2 for eyeshadow
and mascara show the relevance of us-
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Fig. 4 Measurements of (L.) values for determining lightness and darkness of the
pigment in different mediums.
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Ultra Blue Natural Matte Eye Shadow
%
38.91
20.00
15.00
10.00
4.00
2.00
0.05
0.04
10.00
100
Ingredients
MICA S/MM3
TALC N/MM3
BEUB/MM3
FLORITE R
BRO/MM3
BTD/MM3
Methyl Paraben NF
Propyl Paraben NF
PE-48
INCI Name
Mica (And) Magnesium Myristate
Talc (And) Magnesium Myristate
Ultramarines (And) Magnesium Myristate
Calcium Silicate
Iron Oxides (And) Magnesium Myristate
Titanium Dioxide (And) Magnesium Myristate
Methylparaben
Propylparaben
Pentaerythritol Tetraoctanoate
Procedure:
1. Premix all powders including the parabens and then pass them through a micro-pulverizer.
2. Add the liquid binder, PE-48 pentaerythritol tetraoctanoate, and blend well. Do not overheat.
3. Press at 500 psi.
Formulation 1 Ultra Blue Natural Matte Eye Shadow.
Ultramarine Waterproof Mascara
%
55.71
15.00
5.75
0.95
0.05
0.04
1.75
1.75
6.35
1.75
6.25
1.25
2.15
1.25
Ingredients
Soltrol 130
INCI Name
C10-13 Isoparaffin
Hydrogenated Polycyclopentadiene (and)
KOBOGUARD® 5400 IDD
Isododecane
Bentone 38V
Quaternium-18 Hectorite
Phenoxyethanol
Phenoxyethanol
Methyl Paraben NF
Methylparaben
Propyl Paraben NF
Propylparaben
Carnauba Wax, NF
Copernicia Cerifera (Carnauba) Wax
Candelilla Wax, NF
Euphorbia Cerifera (Candelilla) Wax
Asensa SC 210
Polyethylene
Thixcin R
Trihydroxystearin
BEUB-11S2
Ultramarines (And) Triethoxycaprylylsilane
BUV CG-11S2
Ultramarines (And) Triethoxycaprylylsilane
Iron Oxides (C.I. 77499) (And)
BLACK NF-11S2
Triethoxycaprylylsilane
KOBOPEARL® PERPETUAL Synthetic Fluorphlogopite (And) Silica (And)
BlueViolet
Titanium Dioxide
Content
tors to provide new benefits to consumers.
We created dispersions in media that tested
these pigments for their transparency and
opacity in addition to the effects of lightness
and darkness with respect to their refractive
indices. The results helped to show that all
three of the ultramarine pigments behave
similarly for these two physical properties.
They also demonstrate that one can vary
the surrounding media for ultramarines to
create special effects.
With regards to transparency, the ultramarine pigments are a distinct class of
pigments as the R.I. of many cosmetic
liquids and polymers are in the same
range. Therefore, the combinations are
many and can produce excellent results
especially when combined with the more
recent introductions of special effect
pigments based upon borosilicate flakes
or synthetic mica.
Bibliography
(1) A
shok Roy, Artists’ Pigments, A Handbook of
their History and Characteristics – Volume 2,
National Gallery of Art (1993)
(2)
Gunter Buxbaum, Ullmann‘s Encyclopedia
of Industrial Chemistry Pigments, 3. Colored
Pigments, Wiley-VCH (2002)
(3)
Robert Henry Hill, Robert Bruce Order, U.S.
Patent 2806802 A - »Manufacture of ultramarine blue«. Sept. 17, 1957
(4)Nubiola USA, PCI Magazine (Paint and Coatings Industry), 2006
(5) G
unter Bauxham, Industrial Inorganic Pigments p.125, John Wiley & Sonds (2008) p.130
100.00
Procedure:
1. Dissolve the Koboguard® 5400 IDD in the Soltrol 130 at room temperature in a stainless steel beaker. Using
a water bath on a hot plate heat the solution to 85°C under a fume hood using a dispersator for stirring.
2. Add the Bentone 38V and stir at high speed for 15-20 minutes. Add the phenoxyethanol and parabens;
stir 10 minutes.
3. Add the carnauba, candelilla, polyethylene and thixcin. Stir 15-20 minutes or until melted.
4. Add the three pigments, BEUB-11S2, BUV CG-11S2 and BLACK NF-11S2; Stir for 45 minutes at high speed.
5. Add the KOBOPEARL® PERPETUAL BlueViolet and begin cooling. Cool and stir to 30-35°C using an ice bath
Formulation 2 Ultramarine Waterproof Mascara.
32
*Author´s address:
Edward Bartholomey
Principal Research Scientist
Kobo Products Inc., 3474 South Plainfield,
New Jersey, U.S.A.
Tel: +1 908 757 0033
[email protected]
www.koboproducts.com
n
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