NEW T IP A QUE NEWS
Vo.1 Titanium Dioxide Pigments: Basic Physical Properties
TIPAQUE PIGMENTS FOR SUPERIOR PERFORMANCE
& WHITENESS
TIPAQUE
PIGMENTS
FOR
CHAMPION
OF
PERFORMANCE
＆ WHITENESS
0
ISHIHARA SANGYO KAISHA, LTD.
Introduction
Titanium dioxide pigment has excellent whiteness, hiding power, tinting strength and other optical properties,
because it has a higher refractive index and a smaller particle size than zinc white, lithopone, white lead, and
other white pigments. Titanium dioxide pigment is nontoxic, innocuous, stable against heat and light, and
excellently resistant to chemicals; therefore, it is called the "king of white pigments." In Japan, titanium dioxide
pigment makes up approximately 70% of all white pigments.
In 1791, William Gregor extracted a new white metal oxide from iron sand of Manaccan, Cornwall, in the UK.
He named the discovered metal oxide manaccanite. In 1795, M.H. Klaproth separated the same metal oxide from
rutile of Hungary, and named the new element Titan. The Latin word "titanium" derived from a race of gigantic
gods called the Titanes in Greek mythology. Of the present inorganic chemicals, titanium dioxide is the only
chemical efficiently mass-produced by gigantic equipment. Titanium seems symbolic.
In the 20th century, however, titanium dioxide was first used as a pigment. In 1916, the Titanium Pigment
Company succeeded in the world's first industrial manufacture of titanium dioxide by the sulfate process. At first,
titanium dioxide was a combined pigment of anatase-type titanium dioxide and barium sulfate. Nevertheless, it
had approximately 3.5 times the hiding power of white lead used in those days. In the late 1920s, anatase-type
titanium dioxide with a purity of 96% to 99% was developed. In 1940, rutile-type titanium dioxide was
developed. In Japan, although production from domestic iron sand was industrialized in the 1920s, it was not
until our company began importing raw ores (ilmenite) and domestically produced rutile-type titanium dioxide
for the first time, that exported products were recognized as excellent in quality on the international market.
In addition to the above-mentioned sulfate process, the chloride process is also used for the industrial
manufacture of titanium dioxide. In 1957, Du Pont in the U.S. became the first to produce chloride-processed
titanium dioxide. In 1965, American Potash & Chemical Corporation (renamed Kerr McGee Corp. in 1969)
succeeded in industrialization. In Japan, our company introduced American Potash technology, and in early 1974,
we placed chloride-processed titanium dioxide on the market. Our company produces and sells both
sulfate-processed titanium dioxide and chloride-processed titanium dioxide under the Tipaque titanium dioxide
brand.
At present, the ratio of processes for the world's titanium dioxide production is as follows: sulfate
process/chloride process = approximately 40/60. In the U.S., however, chloride-processed titanium dioxide has
reached 95% or more. In the future, the percentage of chloride-processed titanium dioxide will probably increase.
Nowadays, the world's nominal titanium dioxide production capacity is approximately 4,829,000 tons. In 1964,
the Japanese production was 92,000 tons. At present, the Japanese production capacity is estimated 305,000 tons,
which is approximately 3.5 times the 1964 production. The titanium dioxide business has already built up a firm
position in the white pigment industry.
Titanium dioxide pigment is used in paints, inks, plastics, paper, rubbers, chemical fiber fabrics, cosmetics, and
a wide array of other application fields. In these application fields, many companies make efforts to improve
quality, streamline manufacturing methods, and save labor. There is an increasing demand for higher-quality
titanium dioxide as raw material. It is important that demanders select a suitable brand for their particular uses
and manufacturing conditions.
As a reference material, this book describes the basic physical properties of Tipaque titanium dioxide as white
pigment for those studying the appropriate uses for various application fields and the demander's manufacturing
conditions.
This book describes only the basic physical properties. A future volume will cover the applied physical
properties.
1
< CONTENTS >
1. Titanium Dioxide as White Pigment ··············································································· 3
1-1 Physical, chemical properties ······················································································ 3
1-2 Optical properties ······································································································· 5
2. Titanium Dioxide Pigment Production Processes ··························································· 9
2-1 Sulfate process ············································································································ 9
2-2 Chloride process ·········································································································· 10
3. Properties of Titanium Dioxide Pigment ········································································· 11
3-1 Particle size, particle size distribution ··········································································· 11
3-2 Surface treatment ········································································································· 14
3-2-1 Surface treatment agent ························································································· 14
3-2-2 Surface treatment, oil absorption, moisture ···························································· 15
3-3 Dispersion ··················································································································· 17
3-3-1 Dispersion in aqueous & nonaqueous media ······················································ 17
3-3-2 Dispersion in polymer solutions ········································································ 19
3-3-3 Dispersion in plastics ························································································ 22
3-4 Gloss ··························································································································· 24
3-5 Hiding power, tinting strength ······················································································ 26
3-6 Color tone, tinted tone ································································································· 31
3-7 Durability ···················································································································· 33
3-7-1 Photocatalytic ability ···························································································· 33
3-7-2 Imparting durability ······························································································ 35
3-7-3 Resistance to discoloration ···················································································· 38
4. Standards of Titanium Dioxide Pigments ········································································ 41
5. Attached Table (List of Tipaque Brands) ········································································· 42
6. Tipaque Brands and Their Uses ······················································································· 43
Attached Table 1
Titanium dioxide pigment concentration and application fields ··········································· 43
2
1. Titanium Dioxide as White Pigment
The physical properties required for white pigment are as follows:
(1) Excellent whiteness (high reflectance of visible light)
(2) High refractive index
(3) Sufficiently minute particle size for the most efficient light scattering, and sharpened particle size
distribution
(4) High stability against heat and light
(5) Chemical inertness
Whereas some physical properties will not change as basic qualities of titanium dioxide, other physical
properties can be modified to a limited degree through pigment manufacture technology.
The refractive index, for example, is determined by the crystal form of titanium dioxide; therefore, it
cannot possibly be modified by any manufacturing method. In contrast, whiteness and stability against heat
and light can be technologically adjusted to some degree.
1-1 Physical, chemical properties
There are three crystal forms of titanium dioxides: anatase, brookite, and rutile. Only anatase and rutile
are used as pigments.
Both anatase and rutile are tetragonal systems. As shown in Figure 1, rutile has a denser atomic
arrangement in a crystal unit cell than anatase; accordingly, the physical properties are different between
rutile and anatase, as shown in Table 1.
Rutile has a higher stability than anatase. When heated at high temperature, anatase converts into rutile.
At present, industrially produced titanium dioxide pigment is in single particles of 0.15 µm to 0.40 µm.
One-gram pigment consists of approximately 1015 single particles. J.M. Rackham once said, "The single
particle consists of 2.7 x 108 O2− ions and 1.35 x 108 Ti4+ ions, and this crystal contains approximately 102
oxygen defects (Schottky defects)."*
* J.M. Rackham: Pigment & Resin Technology, 1 [4], 7 (1972)
3
Table 1. Comparison between rutile and anatase
Physical Properties
Crystal System
Specific Gravity
Refractive Index
Mohs Hardness
Dielectric Constant
Rutile Type
Tetragonal system
4.2
2.71
7.0～7.5
114
Melting Point
1858℃
Lattice Constant a
Lattice Constant c
Coefficient of
Linear Expansion (25°C)
a axis
c axis
Thermal Conductivity（W／m／K）
Parallel to c axis
Perpendicular to c axis
Specific Heat（cal／mol／℃）
（200～1000℃）
Electric Conductivity（S／cm）
Room temperature
500℃
1000℃
4.58Å
2.95Å
Anatase Type
Tetragonal system
3.9
2.52
5.5～6.0
48
Conversion into rutile
at high temperature
3.78Å
9.49Å
7.19×10-6／℃
9.94×10-6／℃
2.88×10-6／℃
6.64×10-6／℃
10.4*
7.4*
13.2
-13
10
13.0
-14
～10
0.12
-13
-14
10 ～10
5.5×10-8
* Single crystal
Figure 1. Atomic arrangement in unit cell and model
●－TITANIUM
○－OXYGEN
Anatase
Rutile
Titanium dioxide is a tasteless, odorless white powder, and soluble only in hydrofluoric acid and heated
concentrated sulfuric acid. It is quite stable against other mineral acids and alkali, as shown in Table 2.
Under the condition of high temperature in a reducing atmosphere, titanium dioxide reacts with halogen
to produce titanium halide; however, it will not be corroded by hydrogen sulfide or sulfur dioxide.
4
Table 2. Chemical stability of white pigments
Chemical Stability
Properties
Pigment
Hydrochloric
Acid
Nitric Acid
Sodium
hydroxide
Insoluble
Insoluble
Soluble
Soluble
Soluble
Insoluble
Insoluble
Soluble
Soluble
Soluble
Insoluble
Insoluble
Soluble
Soluble
Insoluble
Titanium Dioxide (anatase)
Titanium Dioxide (rutile)
Zinc White
White Lead
Zinc Sulfide
1-2 Optical properties
The refractive index is the first factor in controlling the optical properties of pigment. Of the white
pigments, titanium dioxide has the highest refractive index, and exhibits excellent pigment characteristics,
as shown in Table 3.
Figure 2 is a universal scattering chart* that shows the ratio m (Np/Nb) of the pigment refractive index
Np to the medium refractive index Nb in which light scattering power (scattering power S) is along the
vertical axis, and a function f (π D/λ) of particle size and light wavelength along the horizontal axis. Figure
2 reveals that on conditions of pigment and medium refractive indices and light wavelength, there is an
optimum particle size for maximizing light scattering power.
* Koichi Iinoya: Powder Technology Handbook, Asakura Publishing Co., Ltd. (1965)
Optical properties required for white pigment are high whiteness, high hiding power, and high tinting
strength, each of which is a function (Kubelka-Munk theory) of the light scattering power (S) and light
absorbing power (K) of the pigment. In other words, if coatings, plastics, paper, and other media contain
pigment, their light scattering and absorption are essentially controlled by the light scattering power and
light absorbing power of the pigment and medium. The S value and K value of pigment is not inherent in the
pigment. As shown in Figure 3, for example, they vary depending on the wavelength. Each value is a
function of light wavelength and pigment particle size.
Table 3. Comparison of optical properties of white pigment
Optical Property
Specific Gravity
Pigment　Titanium Dioxide
(A type)
Titanium Dioxide
(R type)
Lithopone
Zinc White
White Lead
Zinc Sulfide
3.9
4.2
－
5.5～5.7
6.8～6.9
4.0
2.52
2.71
－
2.03
2.09
2.37
Hiding Power (ft ／gal)
P.V.C．20％
333
414
118
87
97
－
Refractive Index
2
Tinting strength
1300
1700
260
300
100
660
Ultraviolet Absorption
(% 360 nm)
67
90
18
93
－
35
Reflectance
(% 400 nm)
88～90
47～50
90
80～82
75～78
88
Reflectance
(% 500 nm)
94～95
95～96
96
93～94
90～91
95
5
Figure 2. Relations between light scattering power, medium refractive index, light wavelength, and pigment
particle size
Figure 3. Relations between light scattering power, light absorbing power, and reflectance of titanium
dioxide (rutile type) in coatings, and light wavelength
6
Whiteness is a function of K/S. The smaller the K/S ratio, the higher the brightness. To increase whiteness,
it is necessary to minimize tinting impurities, increase chemical purity, decrease light absorbing power K,
decrease oxygen defects in the crystal, sharpen particle size distribution, disperse particles well in the
medium, and increase light scattering power S.
Hiding power is a function of S and K/S. It is possible to increase hiding power by increasing light
scattering power S by dispersing particles effectively to an appropriate particle size distribution. In terms of
K/S, as light absorbing power K increases, hiding power becomes higher; however, light absorption is
inconsistent with the above-mentioned improvement in whiteness.
Tinting strength is a function of light scattering power S, and improved by increasing light scattering
power S.
Therefore, removal of tinting impurities during production, and selection of particle size for appropriate
distribution are factors in improving optical properties.
Figure 4 shows a comparison of the spectral reflectance of titanium dioxide (anatase type and rutile type)
with those of other white inorganic compounds.* Figure 5 shows the spectral reflectance of anatase type and
rutile type in a range from ultraviolet to infrared.
The whiteness of titanium dioxide is excellent because of its high spectral reflectance in visible light
wavelengths (400 nm to 700 nm). When used as a pigment, rutile-type titanium dioxide functions as an
ultraviolet absorber, and can prevent photo-deterioration of media, because rutile-type titanium dioxide has
high light absorbing power in a range from near ultraviolet to ultraviolet. It should be noted that titanium
dioxide also has photocatalytic ability, which will be described in a separate section.
Anatase-type titanium dioxide has a higher reflectance at shorter wavelengths of visible light than rutile
type. In contrast, rutile-type titanium dioxide has a higher reflectance at longer wavelengths of visible light
than anatase type. Therefore, rutile-type titanium dioxide has a yellowish tone, and anatase-type titanium
dioxide has a bluish tone.
* C.F. Goodeve et al. : Trans. Fas. Soc. 34 (1938)
7
Figure 4 Comparison of spectral reflectance of various pigments
Figure 5 Comparison of anatase type with rutile type
100
Rutile type
90
70
60
50
40
Anatase type
Ultraviolet region
Reflectance (%)
80
Visible light
region
Infrared region
30
20
V
10
B
G YO
R
0
300
400
500
600
700 800
1000
Wavelength (nm)
8
1500
2000
3000
2. Titanium Dioxide Pigment Production Processes
As described in the Introduction, titanium dioxide is produced using two processes: sulfate process and
chloride process.
2-1 Sulfate process
Figure 6 shows a standard flow sheet of the sulfate process.
The raw ore is ilmenite which is produced mostly in North America, South America, India, Norway,
Australia, Malaysia, Sri Lanka, Africa, and the former Soviet Union. Titanium slag which is produced by
eliminating iron from the ilmenite and concentrating it, is also used as a raw material.
The raw ore is ground and then digested with sulfuric acid. Ti and Fe sulfates are extracted from the
digested material. Soluble ferrous sulfate is crystallized, separated, and removed. The remaining titanyl
sulfate solution is filtered, refined, and thermally hydrolyzed to produce precipitate of hydrous titanium
dioxide. Impurities are eliminated in the process of filtering and washing the precipitate. The precipitate is
calcined at 800°C to 1000°C with various additives to produce crude titanium dioxide. Rutile-type titanium
dioxide and anatase-type titanium dioxide are classified by the type of nucleus which is added during
thermal hydrolysis. The crude titanium dioxide goes through the finishing processes such as milling,
classification and surface treatment to give pigmentary properties, and is finished as final product.
(Digestion process) FeTiO3 + 2H2SO4 -> FeSO4 + TiOSO4 + 2H2O
(Hydrolysis process) TiOSO4 + nH2O -> TiO2·mH2O + H2SO4
(Calcination process) TiO2·mH2O -> TiO2 + mH2O
Figure 6. Standard process flow sheet (sulfate process)
Digestion Process
Crystallization
Ore
Hydrolysis Process
Washing
Settling
Filtering
Grinding
Sulfuric
ac id
Hydrolysis
Digestion
Finishing Process
Calcination Process
Drying
Dry milling
Product
Washing
Calcination
treatment
Wet milling,
classification
Finish
grinding
Calcination
Surface treatment
Packaging
9
2-2 Chloride process
Figure 7 shows a standard flow sheet of the chloride process.
High TiO2 raw materials such as natural rutile, synthetic rutile, and high-TiO2 titanium slag are preferred
in order to reduce the consumption of expensive chlorine. Because reserves of natural rutile are limited to
certain area in Australia and Africa, the beneficiation of ilmenite such as synthetic rutile, high-TiO2 slag, is
crucial for this process. Ores are chlorinated under the condition of high temperature in a reducing
atmosphere, and Ti and Fe form titanium tetrachloride (TiCl4) and iron chloride respectively. Through
cooling process, the iron chloride is solidified, where it is separated from the liquid TiCl4.
After the process of distillation, TiCl4 becomes crude titanium dioxide in momentary reaction with
oxygen at the temperature of more than 1000°C.
Since this process has a very short reaction time at very high temperature, all the titanium dioxide
produced from this process in normal conditions is rutile type. The crude titanium dioxide produced through
the oxidation process goes through the same finishing process as in the sulfate process to give pigmentary
properties.
Due to its high cost, the chlorine utilized for reaction is recycled. Simpler process and fewer generation of
industrial waste make the chloride process distinctive compared to sulfate process.
(Chlorination process) TiO2 + C + 2Cl2 -> TiCl4 + CO2
(Oxidation process) TiCl4 + O2 -> TiO2 + 2Cl2
Figure 7. Process flow sheet (chloride process)
Oxidation Process
Chlorination Process
Natural rutile
Synthetic rutile
Separation,
condensation
Preheating
Coke
Chlorination
Chlorine
Oxidation
Oxygen
Separation
Distillation
Recycling (chlorine)
Finishing Process
Drying
Product
Washing
Wet milling,
classification
Finish
grinding
Surface treatment
Packaging
10
3. Properties of Titanium Dioxide Pigment
3-1
Particle size, particle size distribution
Industrially produced titanium dioxide pigment is composed primarily of particles 0.15 µm to 0.40 µm.
Titanium dioxide is required to scatter visible light efficiently enough to exhibit white pigment
characteristics. Determination of particle size is important for this purpose. It is possible to calculate particle
size as a function of light wavelength, medium refractive index, and pigment refractive index. In general, it
can be assumed that if the particle size is half the light wavelength, the pigment will scatter light more
efficiently. As visible light, green light of 500 nm to 560 nm is regarded as the brightest. Particle size of
approximately 0.25 µm is the most suitable for pigment because it scatters light of such wavelengths
efficiently.
As described in the following sections, pigment concentrations vary depending on the use, such as in
paints, inks and plastics. Particle size with the highest hiding power is determined by the pigment
concentration. As shown in Figure 8, we provide three particle sizes of approximately 0.25 µm so Tipaque
titanium dioxide (rutile type) exhibits the optimum hiding power for each usage. The particle size that we
provide here is generally referred to as the primary particle size.
Figure 8. Average primary particle size of Tipaque titanium dioxide
1) Small particles (0.21 µm)
2) Medium particles (0.25 µm)
１μｍ
１μｍ
3) Large particles (0.28 µm)
１μｍ
As shown in Figure 9, titanium dioxide particles can be classified into four forms: (1) single particles
(primary particles); (2) clusters (aggregates), each of which consists of several sintered single particles; (3)
clusters (agglomerates), each of which consists of single particles that adhere to each other because the
particles are covered with surface treatment agent; and (4) clusters (flocculates), each of which consists of
several single particles that adsorb moisture and gather around it.
11
Figure 9. Particle forms
(1) Primary
(Primary particles
(single particles))
(2) Aggregates
(3) Agg1omerates
(Aggregates)
(Agglomerates)
(4) Flocculates
(Flocculates
(reversible aggregates))
In contrast to form (1) of primary particles, forms (2), (3) and (4) are referred to as secondary particles.
As a product, titanium dioxide pigment contains both primary and secondary particles. In paints, plastics,
and other media, however, secondary particles are destroyed by dispersion energy. Titanium dioxide pigment
eventually resembles primary particles and exhibits the required pigment characteristics. Despite the
dispersion energy, secondary particles of forms (2) and (3) are difficult to destroy. It is desirable that
pigment contains as few secondary particles of forms (2) and (3) as possible. In the production process,
therefore, precision control of particle size by grinding and classification is carried out.
Particle size distribution is required to be sharpened at the optimum particle size so that a product may
exhibit pigment characteristics effectively. Table 5 and Figure 10 show the primary particle size distribution
measurements of major Tipaque titanium dioxide brands that have different particle sizes. Table 6 and
Figure 11 show an example measurement of secondary particle size distribution.
Table 5. Primary particle size distribution of Tipaque titanium dioxides
Particle Size
(μm)
CR-60
(Small size, rutile)
CR-50
(Medium size, rutile)
CR-58
(Large size, rutile)
0.10↓
0.10～0.15
0.15～0.20
0.20～0.25
0.25～0.30
0.30～0.35
0.35～0.40
0.40～0.45
0.45↑
Avg. size(μm)
0.5
6.3
25.2
43.7
21.5
2.8
－
－
－
0.3
2.6
13.3
29.2
32.3
18.1
4.2
－
－
0.1
1.5
7.9
20.6
32.4
23.6
10.2
2.9
0.8
0.21
0.25
Brand Crystal Form Particle Size
CR-60
Rutile
Small
Al
CR-50
Rutile
Medium
Al
CR-58
Rutile
Large
Al
0.28
(Unit: % by weight)
* Measured with an image analysis system (LUZEX III U) based on transmission electron micrographs.
12
Surface
Treatment
Figure 10. Primary particle size distribution of Tipaque titanium dioxides
50
CR-60（Small）
Frequency（％）
40
30
CR-50（Medium）
20
CR-58（Large）
10
0.45↑
0.40～0.45
0.35～0.40
0.30～0.35
0.25～0.30
0.20～0.25
0.15～0.20
0.10～0.15
0.10↓
0
0
Particle size（μm）
Table 6. Secondary particle size distribution of Tipaque titanium dioxides
Particle size
(μm)
CR-60
(Small size, rutile)
CR-50
(Medium size, rutile)
CR-58
(Large size, rutile)
0.20～0.26
0.26～0.34
0.8
5.6
0.7
6.1
0.2
2.8
0.34～0.45
0.45～0.58
16.9
24.7
20.4
29.6
14.0
27.5
0.58～0.77
0.77～1.00
24.6
16.2
25.0
12.3
29.4
17.0
1.00～1.32
1.32～1.73
1.73～2.27
8.2
2.6
0.5
4.6
1.2
0.1
7.0
1.8
0.2
Avg. size(μm)
0.60
0.55
Brand Crystal Form
Particle Size
CR-60
Rutile
Small
Surface
Treatment
Al
CR-50
Rutile
Medium
Al
CR-58
Rutile
Large
Al
0.61
(Unit: % by weight)
Measuring apparatus: Horiba LA-910 Particle Size Distribution Analyzer
Dispersing medium: 0.3% sodium hexametaphosphate aqueous solution with pH of 10.5 (by NaOH)
13
Figure 11. Secondary particle size distribution of Tipaque titanium dioxides
40.0
CR-58（Large）
Frequency（％）
30.0
CR-50（Medium）
20.0
10.0
CR-60（Small）
1.73～2.27
1.32～1.73
1.00～1.32
0.77～1.00
0.58～0.77
0.45～0.58
0.34～0.45
0.26～0.34
0.20～0.26
0.0
Particle size（μm）
* Such secondary particle size data are merely examples of measurements, and do not completely
represent a practical system.
In Figure 11 of these data, particle size distribution of CR-60, which has small particle size, is
broad probably because particles of smaller size have stronger cohesion.
3-2 Surface treatment
3-2-1 Surface treatment agent
Titanium dioxide is an inherently hydrophilic substance. If used as a pigment, however, it is common that
titanium dioxide particles are treated with various hydrous metal oxides and organic substances on their
surfaces so that particles can have an affinity for the medium, or active sites on particle surfaces are covered
with a surface treatment agent to impart durability to particles.
Aluminum, silicon, titanium, zinc and zirconium oxides are used as hydrous metal oxides. Figure 12(a)
shows non-treated particle surfaces. As shown in Figure 12(b), titanium dioxide particle surfaces are
covered with such a hydrous metal oxide. TiO2 particle surfaces are treated with several percent of hydrous
metal oxide. Layer thickness is several tens of angstroms.
In general, using inorganic surface treatment agent Al2O3 improves titanium dioxide particles' affinity for
binder, thereby imparting dispersibility to the particles. On the other hand, SiO2 treatment and ZrO2
treatment inhibit the photocatalytic ability of titanium dioxide, thereby imparting durability to the particles.
Some organic polyol substances improve the particles' ability to wet binder, thereby acting as a dispersing
agent. Some organic substances are expected to modify the particle surfaces. Siloxane and silane coupling
agent, for example, impart water repellency to the particles. (Details of each surface treatment agent will be
described in the following sections.)
14
Figure 12. Observation of particle surfaces
(a)
(b)
０．５μｍ
０．５μｍ
(a) Titanium dioxide particles with non-treated surfaces
(b) Titanium dioxide particles (CR-50) with treated surfaces
3-2-2 Surface treatment, oil absorption, moisture
Although titanium dioxide particle surface treatment can impart dispersibility, durability, and other
qualities to the particles, the surface treatment agent increases the oil absorption and water content of the
pigment, which varies depending on the surface treatment method, agent, and quantity employed.
Table 7 shows oil absorption data. It is found that oil absorption varies depending on the surface
treatment quantity (TiO2 content) as well as the surface treatment agent and method used. Higher oil
absorption increases the viscosity of paints and inks, and may cause other inhibitions. For general
applications, a larger quantity of surface treatment agent lowers the TiO2 content, causing decreases in
hiding power and gloss. Therefore, an appropriate brand selection for each application is required
considering possible inhibition and physical properties imparted by surface treatment. On the other hand, for
use in flat emulsion paints and lamination printing gravure inks with high pigment concentration, some
brands contain high-oil absorption titanium dioxide particles covered with a large quantity of surface
treatment agent, thereby developing a dry hiding effect and imparting high hiding power to the particles.
(This effect will be described in the following sections.)
Table 7. Tipaque titanium dioxide and oil absorption
Non-treated
CR-50
CR-80
R-780
R-780-2
Surface Treatment
Agent
TiO2 Content
(%)
Oil Absorption
（g/100g）
－
Ａｌ
Ａｌ＋Ｓｉ
Ａｌ＋Ｓｉ
Ａｌ＋Ｓｉ
99.6
96.3
93.9
90.5
81.4
15
18
20
33
40
15
Titanium dioxide pigment contains physically adsorbed water and chemically bound water. Physically
adsorbed water means, because of the hydrogen bond to the OH group on the treated titanium dioxide
particle surface, water is adsorbed on the surface, and further forms a physisorption layer of water. A larger
quantity of surface treatment agent increases physically adsorbed water. The larger the specific surface area,
the more the physically adsorbed water. When heated to 100°C, physically adsorbed water molecules in the
outermost layer start desorption first, because the binding energy is the lowest. The quantity of physically
adsorbed water is not always constant because low-binding energy molecules in the outer layer can cause
desorption or adsorption, depending on the ambient humidity and temperature. On the other hand, because
the surface treatment agent is a hydrate, the titanium dioxide pigment contains chemically bound water,
which varies depending on the surface treatment agent, method, and quantity employed. Chemically bound
water has a higher desorption temperature than physically adsorbed water, and gradually starts desorption at
150°C.
Water content has an influence especially on the use of titanium dioxide pigment in the plastics field. Of
the various types of plastics, engineering plastics are processed at such a high temperature that physically
adsorbed water and chemically bound water contained in the titanium dioxide pigment cause a large quantity
of desorption, and may cause foaming, gumming, die streaks, lacing, and other defects. For use in
polyethylene terephthalate (PET) and polycarbonate resins, titanium dioxide pigment triggers resin
hydrolysis, and poses a serious problem. For use in the plastics field, generally, particles that have surfaces
treated with a smaller quantity of inorganic surface treatment agent are preferred. By treating them with
siloxane and silane coupling agent, the manufacturer preferably imparts water repellency to the particles in
order to decrease physically adsorbed water. Table 8 shows the Karl Fischer moisture measurements. KF
moisture varies depending on the surface treatment agent and quantity.
Table 8. KF moisture of Tipaque titanium dioxides
Surface Treatment Agent
TiO2 Content
(%)
100℃
(ppm)
300℃
(ppm)
Δ300℃－100℃
CR-60-2
Al + polyol
96.8
2400
6300
3900
CR-63
Al + Si + siloxane
97.6
1300
3600
2300
CR-50-2
Al + polyol
96.3
3000
7500
4500
CR-90-2
Al + Si + polyol
92.2
7500
13100
5600
16
3-3 Dispersion
3-3-1 Dispersion in aqueous & nonaqueous media
Titanium dioxide particle surfaces are treated with hydrous metal oxides, mainly Al2O3·nH2O and
SiO2·mH2O. Oil absorption and water absorption are controlled by the ratio of Al2O3/(Al2O3 + SiO2) and the
total quantity of surface treatment agent. Figure 13 shows this relationship. The higher the rate of Al2O3 in
surface treatment agent, the lower the oil absorption. In other words, Al2O3 imparts lipophilicity to the
particles; SiO2, hydrophilicity. As the total quantity of surface treatment agent increases, both oil absorption
and water absorption become high.
Dispersibility of titanium dioxide in water is also controlled by pH level. As shown in Table 9, dispersion
regions are different between Al2O3 treatment and SiO2 treatment. For reference, Figures 14 and 15 show the
dispersibility of Tipaque titanium dioxides in water.
Titanium dioxide particles are not dispersed in nonaqueous, nonpolar media as shown in Table 10. If
particle surfaces are treated with SiO2, however, titanium dioxide particles are dispersed even in a relatively
low-polarity medium like acetone.
In low-polarity media, titanium dioxide particles and other higher-polarity powders have low heat of
wetting, and generally cause aggregation. In high-polarity media, such as alcohol and water, they have high
heat of wetting, and are stabler in terms of dispersion. If particle surfaces are treated, titanium dioxide
pigment's affinity for the medium is controlled by using hydrous oxide as a surface treatment agent.
Figure 13. Al2O3/(Al2O3 + SiO2) and oil absorption and water absorption
17
Table 9. Dispersibility in aqueous media
Dispersibility
ｐＨ
2
3
4
5
6
7
8
9
10
11
12
Al2O3
◎
◎
◎
◎
◎
×
×
×
◎
◎
◎
Al2O3 ＞ SiO2
◎
◎
◎
◎
×
×
×
◎
◎
◎
◎
Al2O3 ＜ SiO2
◎
◎
◎
×
×
×
◎
◎
◎
◎
◎
Surface Treatment
◎: Excellent dispersion　×: Poor dispersion
* These data are merely examples. If particles have undergone Al2O3/SiO2 combined surface treatment, their
dispersibility in water differs depending on the method and quantity of surface treatment agent employed.
Figure 14. Dispersibility of Tipaque titanium dioxides (anatase type) in water
Brand Crystal Form Surface Treatment
100
Dispersibility in Water（％）
W-10
80
60
W-10
Anatase
－
A-100
Anatase
－
A-220
Anatase
Al
A-220
40
20
A-100
0
3
3.5
4
4.5
5
5.5
6
6.5 7
ｐＨ
7.5
8
8.5
9
9.5 10 10.5
Figure 15. Dispersibility of Tipaque titanium dioxides (rutile type) in water
Brand Crystal Form Surface Treatment
Dispersibility in Water （％）
100
80
60
CR-90
CR-80
40
0
3.5
4
4.5
5
5.5
6
6.5
7
7.5
Rutile
Al
CR-80
Rutile
Al, porous-Si (Al2O3>SiO2)
CR-90
Rutile
Al, dense-Si (Al2O3<SiO2)
* W-10 is a brand that has self-dispersibility
in water in a wide pH range, and is used to
manufacture paper.
CR-50
20
3
CR-50
8
8.5
9
9.5 10 10.5
ｐＨ
18
Table 10. Dispersibility in nonaqueous media
Nonaqueous Media (Dispersibility %)
Surface Treatment
Al2O3/（Al2O3＋SiO2）
Xylene
CCl4
Ethyl
Acetate
1-Butanol
Acetone
DMF
Methanol
Ethylene
Glycol
DMSO
０．３
０
０
０
５０
７２
８５
７０
９５
８０
０．４
０
０
０
０
２０
９０
６５
９５
８０
０．８
０
０
０
８０
０
８０
９５
９５
８５
3-3-2 Dispersion in polymer solutions
To produce excellent dispersion of titanium dioxide in polymer solutions, and to stabilize dispersion in
paints and inks, it is important to use the steric hindrance effect due to the polymer (resin) adsorption to the
titanium dioxide particle surfaces. The resin adsorption to titanium dioxide has a great influence on the
acidity/basicity of the pigment surfaces. Titanium dioxide is an inherently amphoteric compound that acts as
a solid acid or solid base, depending on the ambient substance. If used as a pigment, however, titanium
dioxide particles have surfaces treated with SiO2, Al2O3 and other agents, so that the acidity/basicity of the
surfaces depends greatly on the surface treatment agent used.
Figure 16 shows the acidity/basicity of titanium dioxide particles that have surfaces treated with various
agents. It is found that as surface treatment agents, Al2O3 and ZrO2 impart basicity to the particles; SiO2,
acidity.
Figure 16 Surface treatment agents and surface acidity/basicity
Base amount (µmol/g)
80
60
40
20
Acid amount (µmol/g)
0
0
Non-treated
Al2O3 treatment
SiO2 treatment
ZrO2 treatment
19
20
40
We prepared two acrylate resins as shown in Figure 17, and measured the polymer (resin) adsorption to
the titanium dioxide particle surfaces. Table 11 shows the measurements. As basic surface treatment agents,
Al2O3 and ZrO2 have higher acidic-resin adsorption than SiO2. As an acidic surface treatment agent, SiO2 has
higher basic-resin adsorption than Al2O3 and ZrO2. As described above, the steric hindrance effect due to the
high resin adsorption produces excellent dispersion in media, leading to improved gloss, hiding power,
tinting strength, and other physical properties of the coating. For commonly available acidic resins, the use
of Al2O3-treated and Al2O3+ZrO2-treated titanium dioxide brands are regarded as effective. SiO2-treated
brands, in general, are products that have undergone an Al2O3/SiO2 combined surface treatment, and
accordingly can be used for acidic resins.
Figure 17. Preparation of model acrylate resins
MMA : Methyl methacrylate
Acidic resin
MMA
E HA
EHA : Ethylhexylacrylate
MA A
MAA : Methacrylic acid
COOH
DMAEMA : Dimethylaminoethylmethacrylate
Basic resin
MMA
E HA
D M A EM A
NR 2
Table 11. Resin adsorption measurements
Resin Adsorption （mg/g-TiO2)
Surface
Treatment
Non-treated
Al2O3
SiO2
ZrO2
Acidic Resin
Solids
Content
1%
17.9
26.3
14.4
24.1
Solids
Content
5%
13.9
23.5
13.2
22.1
Basic Resin
Solids
Content
1%
15.1
17.5
21.2
18.3
Solids
Content
5%
14.2
20.3
19.1
17.4
As described above, the acidity/basicity of titanium dioxide particle surfaces has a great influence on the
dispersibility of titanium dioxide in acidic or basic media. The surface charge of titanium dioxide particles in
the media also has a great influence on dispersibility. It is said that the acidity/basicity of titanium dioxide
particle surfaces has a great influence on solvent-type paints, and that the titanium dioxide particle surface
charge has a great influence on water-soluble paints and water-based emulsion paints.
For titanium dioxide particles that have surfaces treated with various agents, Table 12 shows the particle
surface charges in water and in water-soluble acrylate resin paint.
20
Table 12. Zeta potentials in water and in water-soluble acrylate paint
Zeta Potential (mV)
Surface
Treatment
(1) In Water
Non-treated
Al2O3
SiO2
ZrO2
(2) In Water-soluble
acrylate paint
－１７
４６
－５７
－６
* * pH = 8.5 for all items
Difference
(1)－(2)
－５４
－７８
－４９
－６４
３７
１２４
－８
５８
There is not a complete correlation between zeta potentials in water and in water-soluble acrylate paint.
For Al2O3 treatment, the zeta potential is greatly different. For SiO2 treatment, however, the zeta potential is
almost the same, probably because Al2O3 treatment facilitates resin adsorption whereas SiO2 treatment does
not work. As shown in Figure 18, there is a correlation between the zeta potential in water and the difference
in zeta potential between water and water-soluble acrylate paint. There is also a correlation between this zeta
potential and coating gloss. As shown in Figure 19, if particles have significant negative charge, they cause
strong electric repulsion against anionic resin and anionic surface-active agents, and do not facilitate resin
adsorption. But if particles have significant positive charge, they cause weak repulsion, and facilitate resin
adsorption. Entropic repulsion (steric hindrance effect by the adsorption layer) and the DLVO theory based
on the zeta potential explain the titanium dioxide dispersion in such aqueous polymer solutions. The sign and
magnitude of the zeta potential, and adsorption, are greatly influenced by the composition of the titanium
dioxide particle surface being treated.
Figure 18. Zeta potential and coating gloss
100
90
80
In water
Gloss
70
Difference between in
water and in paint
60
50
40
30
20
10
0
-80
-60
-40
-20
0
20
40
60
Zeta Potential (mV)
21
80
100
120
140
Figure 19. Interaction between titanium dioxide and resin
Titanium dioxide
－
Repulsion: Strong
－
－
－ －
Resin
－
－
－
－
－
－
－
－－
Repulsion: Weak
－－
－
－
－
－
3-3-3 Dispersion in plastics
The dispersibility of titanium dioxide particles in plastics is determined by the particles' ability to wet the
resin, and by the secondary aggregates' ability to collapse. Because titanium dioxide is a high-polarity
substance, it will not easily wet low-polarity resins like polyethylene. To assist titanium dioxide pigments in
wetting low-polarity resins, it is necessary to produce low-polarity pigment particle surfaces. Two main
modification methods are used:
1) Decreasing water contained in titanium dioxide (to prevent secondary aggregation due to the water
desorption in high-temperature processing)
2) Modifying pigment particle surfaces with an organic substance to produce lower-polarity surfaces.
If titanium dioxide particle surfaces are treated with polyol, siloxane, a silane coupling agent, or other
organic substance, generally the organic substance decreases water adsorption and produces low-polarity
pigment particle surfaces. The dispersibility of titanium dioxide particles in plastics is thereby improved.
Treating particle surfaces with a smaller quantity of inorganic surface treatment agent, such as Al2O3 and
SiO2, as described above, can decrease the influence of desorption of physically adsorbed water and
chemically bound water contained in surface treatment agents in high-temperature processing.
For plastics, we evaluated the dispersibility of major Tipaque titanium dioxide brands in two resin systems.
Table 13 and Figure 20 show these evaluations.
1) Dispersibility in flexible PVC (polyvinyl chloride plastic): Using a two-roll mill, we kneaded resin with
a weak shear to produce a sheet, and compared the densities of undispersed particles in the resin sheet.
2) Dispersibility in polyethylene: We installed a #400 mesh screen in a twin-screw extruder die, and
measured the increase in resin pressure due to the screen clogging in kneading.
22
Table 13. Dispersibility in flexible PVC
Dispersibility
Brand
(Visual check of undispersed particles.)
CR-60-2, CR-63
◎
CR-60, CR-90-2
〇
CR-90
△
A-100
×
Undispersed particles are checked visually
（excellent/small number）◎＞〇＞△＞×（poor/large number）
Brand
A-100
CR-60
CR-60-2
CR-63
CR-90
CR-90-2
Crystal Form
Anatase
Rutile
Rutile
Rutile
Rutile
Rutile
Particle Size
Small
Small
Small
Small
Medium
Medium
Surface Treatment
－
Al
Al, Polyol
Al, Si, Siloxane
Al, dense-Si
Al, dense-Si, Polyol
Figure 20. Comparison of dispersibilities (increase in resin pressure) in LDPE system
Resin Pressure（kg/cm 2 ）
220
200
CR-90
180
CR-60
160
140
CR-90-2
120
CR-63
100
CR-60-2
80
60
0
10
20
30
Kneading Time (min)
23
40
50
3-4 Gloss
The gloss of coatings and ink layers is determined theoretically by the refractive index of the surface and
surrounding environment of the coating. However, in practical systems, the smoother the coating surface, the
higher the gloss, as shown in Figure 21. Smoothness depends greatly on the particle size distribution
(secondary particle size distribution) of titanium dioxide in paints and inks. In other words, if most
secondary particles of titanium dioxide have collapsed in the coating, and if the actual particle size
distribution resembles the primary particle size distribution, such a state of dispersion is ideal. Aggregates
damage the smoothness of coating surfaces, causing a decrease in gloss. The above-mentioned dispersibility
has a very great influence on high-gloss coatings.
Figure 21. Dispersion and gloss
1) (Excellent-dispersion coating)
2) (Poor-dispersion coating)
Light
Surface is smooth,
coating has high gloss,
and finished appearance
is excellent.
Surface is irregular,
coating has low gloss,
and finished appearance
is poor.
Figure 22 shows the changes in gloss as we varied the time for dispersion of particles in alkyd resin, a
solvent-type paint. Each of the samples had its gloss improved by extending the dispersion time. The
Al2O3/SiO2-treated product initially had low gloss; within a short period of dispersion time, however,
extending the dispersion time increases gloss significantly. Extending the dispersion time decreases
differences between Al2O3/SiO2-treated products and other products. In practical systems, however,
producing high-gloss coatings using the least amount of energy is ideal. Even the Al2O3/SiO2-treated product
particle surfaces can be further treated with an organic substance. The product's dispersibility is thereby
improved, as described above. Dispersibility is also improved by a newly devised production process for
sharpening the particle size distribution.
24
Figure 22. Gloss and dispersion time in paint system (using paint shaker)
(Solvent-type alkyd/melamine resin paint system)
100
Gloss　20°－20°
90
80
70
60
50
Titanium dioxide/resin solids
content = 1/1
Dispersing medium: glass beads
40
30
0
15
30
Dispersion Time (min)
25
45
60
3-5 Hiding power, tinting strength
3-5-1
Hiding power, tinting strength
As described in Section 1-2, hiding power is a function of S and K/S (S: light scattering power. K: light
absorbing power). Because titanium dioxide is a white pigment, the use of titanium dioxide for hiding is
inconsistent with improving hiding power by increasing light absorbing power K. Therefore, the hiding
power of titanium dioxide is improved by increasing light scattering power S. Because tinting strength is a
function of light scattering power S, it is also necessary to increase light scattering power S to produce high
tinting strength. This section focuses on hiding power.
In general, the pigment concentration in a practical system correlates with the thickness of a practical
system, such as the thickness of plastic molding, thickness of a coating, and thickness of a gravure ink layer.
Relatively low-concentration pigment is used in a thick plastic molding. The use of a thin gravure ink layer
for hiding involves increasing pigment concentration. (Attached Table 1 shows the relations between
titanium dioxide concentration and various applications. <page 32>) Considering the optimum particle size,
surface treatment, and other factors in each usage, the user must select a titanium dioxide product that can
produce high hiding power and high tinting strength in each usage.
The optimum particle size for high hiding power and high tinting strength depends on the pigment
concentration in the medium. Figure 23 shows the relation between pigment concentration and hiding power
for each particle size. At low pigment concentrations, the smaller the particle size, the higher the hiding
power. This is because if pigments have the same concentration but different particle sizes, there are a
different number of pigment particles in each binder, and because the pigment has a smaller particle size,
there are a larger number of pigment particles in the binder; accordingly, the particles produce a larger light
scattering surface area.
Figure 23. Hiding power and pigment concentration
Hiding Power
Dry Hiding
Crowding effect
Medium 0.25μｍ
Large 0.28μｍ
Small 0.21μｍ
Pigment Concentration
26
At medium concentrations, hiding power is a decreasing function of pigment concentration, because of the
crowding effect shown in Figure 24. The crowding effect is a phenomenon in which light scattering
efficiency and hiding power decrease. This is because since the pigment has higher concentration, there is a
shorter distance between pigment particles, and because if the distance is less than half the incident light
wavelength, the pigment acts not as optically discrete particles but as optically coarse particles, causing a
decrease in light scattering efficiency. The smaller the particle size, the shorter the distance between particles.
As pigment concentration increases, therefore, the crowding effect influences each of the small-particle size,
medium-particle size, and large-particle size products, in this order. At higher pigment concentrations, the
larger the particle size, the higher the hiding power. Although, in general, hiding power depends on pigment
particle size distribution, dispersion in the binder, quality of the binder, and other factors, roughly speaking,
the small-particle size product has the highest hiding power at a PVC (pigment volume concentration) of 5%
or less, the medium-particle size product has the highest hiding power at a PVC of 5% to 20%, and the
large-particle size product has the highest hiding power at a PVC of more than 20%. For reference, Figure 25
shows the hiding power of different-particle size Tipaque titanium dioxide products in a solvent-type
alkyd/melamine resin paint system at medium concentrations.
Figure 24. Relation between pigment concentration and particle size (crowding effect)
Low pigment
concentration
Small particle size
Large particle size
High pigment
concentration
Figure 25. Scattering coefficient S (550 nm) and pigment concentration
9
Scattering coefficient S
8
7
6
5
4
Small particle size
3
Medium particle size
2
Large particle size
1
0
0
5
10
15
20
25
30
35
PVC (%)
27
40
45
At much higher pigment concentrations, especially at the critical PVC (CPVC), pigment particles are in
the closest packing state in which pigment particles touch each other. At concentrations higher than the
CPVC, a lack of binder required to cover the whole pigment particles causes air bubbles in the binder, as
shown in Figure 26. At concentrations lower than the CPVC, only interfaces between the pigment particles
and binder scatter light. At concentrations higher than the CPVC, it is necessary to consider not only light
scattering interfaces between the pigment particles and binder but also light scattering interfaces between the
binder and air bubbles, as well as interfaces between pigment particles and air bubbles. Because air bubbles
have low refractive indices, there is a large difference between the titanium dioxide refractive index and the
apparent refractive index of binder that contains air bubbles; accordingly, higher light scattering can be
produced. Although hiding power is a decreasing function of pigment concentration due to the crowding
effect, hiding power is at its minimum at the CPVC. At concentrations higher than the CPVC, hiding power
is an increasing function of pigment concentration.
Thus, there is a close relation between pigment concentration and optimum particle size. To produce high
hiding power, it is necessary to select the optimum particle size according to the pigment concentration used.
According to practical systems, the user may attach great importance to other physical properties (such as
durability and color tone), not to hiding power. In such cases, he or she may select a particle size according
to the physical properties.
For pigment concentrations higher than the CPVC, titanium dioxide particles are often used that have
surfaces treated with a large quantity of agent. Because such treated titanium dioxide particles absorb a large
quantity of oil, the CPVC shifts to a lower concentration. High oil absorption facilitates development of the
dry hiding effect. As shown in Figure 27, even if titanium dioxide particles are packed as close together as
possible, thickly treated surface layers prevent titanium dioxide particle cores from touching each other;
therefore, the titanium dioxide particles are resistant to the crowding effect. The larger the quantity of surface
treatment agent, the lower the TiO2 content. Although some people are deeply concerned about the decrease
in hiding power due to the low TiO2 content, the dry hiding effect cancels it out.
Figure 26. Dry hiding effect
Below CPVC, coating contains no air bubbles.
(Refractive index of binder does not change.)
Nb=1.5
Np=2.7
Above CPVC, coating contains air bubbles.
(Apparent refractive index of binder decreases.)
Nb<1.5
Np=2.7
Np: refractive index of titanium dioxide
Nb: refractive index of binder
28
4) Figure 27. Models of much treated brands
Standard brand
Much treated brand
Much treated brand contains so
many gaps between particles that it
easily produces dry hiding effect.
Flat emulsion paint extenders for various purposes include calcium carbonate, clay, talc, and other
extender pigments besides titanium dioxide. Such paint systems have very high total pigment concentrations,
with some paints having a total PVC as high as 70%. Because there is little or no difference in refractive
index between such extender pigments and the binder, the extender pigment will not develop hiding power
by itself. High hiding power is developed by using the extender pigment with titanium dioxide, setting total
pigment concentration to a high level, and then making the best use of the high refractive index of titanium
dioxide and the dry hiding effect. Such paint systems have a variety of total pigment concentrations and
ratios of titanium dioxide to extender pigment. Titanium dioxide products required to develop the highest
hiding power differ depending on these conditions.
As shown in Table 14 and Figure 28, under conditions of high total pigment concentration and high ratio
of titanium dioxide to extender pigment, the highest hiding power is achieved with a titanium dioxide
product that has particle surfaces treated with a larger quantity of agent, which absorbs a much larger
quantity of oil than standard products. Under conditions of low total pigment concentration and low ratio of
titanium dioxide to extender pigment, high hiding power is achieved by standard products. This is because
there is a trade-off between the dry hiding effect and TiO2 content. In terms of systems that contain extender
pigment, it is also necessary to consider the influence of the crowding effect between titanium dioxide
particles on hiding power. The influence of the crowding effect varies depending on the particle size of the
extender pigment. If the extender pigment particles are much larger than the titanium dioxide particles, as
shown in Figure 29, the titanium dioxide particles are susceptible to the crowding effect.
29
Table 14. Relations between TiO2 content, oil absorption, and hiding power
Brand
TiO2
Content
(%)
Oil Absorption
(g/100 g)
CR-57
R-780
R-780-2
95.7
90.5
81.4
17
33
40
Reflectance of Coating on Black substrate (Y)
PVC=65%
PVC=55%
PVC=45%
TiO2/CaCO3
TiO2/CaCO3
TiO2/CaCO3
1/1 1/3 1/5 1/1 1/3 1/5 1/1 1/3 1/5
80.1
85.8
86.9
80.3
82.1
82.3
76.1
77.5
77.1
78.5
85.9
87.1
70.4
72.4
72.6
66.8
65.7
65.0
80.7
80.2
80.1
71.1
68.3
65.8
64.4
59.9
57.1
Figure 28. Relations between total pigment concentration, ratio of titanium dioxide to extender pigment,
and hiding power
CR-57
R-780
R-780-2
CR-57
R-780
R-780-2
1/3
CR-57
R-780
R-780-2
1/5
CR-57
R-780
R-780-2
1/1
TiO2／CaCO3
TiO2／CaCO3
1/1
ＰＶＣ＝４５％
ＰＶＣ＝５５％
CR-57
R-780
R-780-2
1/3
CR-57
R-780
R-780-2
1/5
55 60 65 70 75 80 85 90 95
55 60 65 70 75 80 85 90 95
Hiding Power (Yb)
Hiding Power (Yb)
CR-57
R-780
R-780-2
1/1
TiO2／CaCO3
ＰＶＣ＝６５％
1/3
1/5
CR-57
R-780
R-780-2
CR-57
R-780
R-780-2
55 60 65 70 75 80 85 90 95
Hiding Power (Yb)
Figure 29. State of titanium dioxide particles and calcium carbonate particles in coating
TiO2
TiO2
CaCO3
CaCO3
30
3-6 Color tone, tinted tone
At visible light wavelengths, as pigment particle size decreases, the scattering power peak shifts to shorter
wavelengths. As particle size increases, the peak shifts to longer wavelengths. In other words, small particles
have a bluish reflection; large particles, a reddish reflection. Figure 30 shows the relations* between
rutile-type titanium dioxide particle size and specific scattering power for blue, green and red rays.
* R.J. Bruehlman, L.W. Thomas, E. Gonick: Off. Dig., 33, 252 (1961)
Figure 30 Particle size and specific scattering power of rutile type titanium dioxide
7
Specific Scattering Power
6
Blue
5
(450nm)
Green
4
(555nm)
3
2
Red
(600nm)
1
0
0 .0 5
0 .1 0
0 .1 5
0 .2 0
0 .3 0
0 .5 0
0 .8 0
Particle Size μｍ
Even if a system is toned by a pigment other than titanium dioxide, relations between particle size and
scattering power are similar. It is possible, however, to see an even clearer difference in tinted tone between
particle sizes than with a white color tone. Figure 31 shows a model of reflection from a gray coating formed
of titanium dioxide and carbon black pigment. Incident light is absorbed by the carbon black pigment, and
reflected by the white pigment. The smaller the titanium dioxide particle size, the higher the scattering rate
of short-wavelength blue light; accordingly, a shorter light path occurs in the coating. Because
long-wavelength red light has a lower scattering rate than blue light, a longer light path occurs in the coating.
Long-wavelength light is absorbed in carbon black than short-wavelength light. Therefore, the percentage of
blue light in the entire reflection increases. The smaller the particle size, the bluer the tone. Because a white
system contains titanium dioxide but not any carbon black that absorbs light, the white system exhibits a
small difference in color tone between particle sizes. Table 15 shows the color measurements of the actual
white coating and tinted coating.
31
Figure 31. Model of reflection from gray coating (*）
Incident light
Short-wavelength light
Long-wavelength light
←TiO2 particle
←Carbon black particle
Substrate
(*）
R.J.Bruehlman, L.W.Thomas, E.Gonick,Off.Dig.,33, 252 (1961)
Table 15. Color tone and tinted tone in alkyd/melamine paint system
White Coating
Brand
CR-60 (Small particle size)
CR-50 (Medium particle size)
CR-58 (Large particle size)
L
96.0
96.1
96.1
a
-0.8
-0.8
-0.7
b
0.4
0.6
0.7
Gray Coating
L
46.5
47.7
47.6
a
0.1
-0.1
-0.1
b
-6.6
-5.0
-3.8
* Alkyd/melamine resin paint system: PVC = 20%
Gray system: titanium dioxide/carbon black = 100/1.5
CR-60
(Small particle size)
CR-50
CR-58
(Medium particle size) (Large particle size)
32
3-7 Durability
3-7-1 Photocatalytic ability
It is well known that titanium dioxide has photocatalytic ability, such that if plastic moldings, paints, ink
layers and other organic media containing titanium dioxide are irradiated with ultraviolet light, titanium
dioxide acts on decomposition of the organic medium. Titanium dioxide is a photosemiconductor that, at
ordinary temperatures, has a band gap of approximately 3 eV (rutile type), which corresponds to the energy
of light at 410 nm. As shown in Figure 32, an electron (e−) is excited from the valence band to the
conduction band by irradiating with light that has a higher energy than the band gap, that is, ultraviolet light
that has a wavelength of less than 410 nm, to produce a hole (h+) in the valence band. The excited electron
(e−) moves to the particle surface. The electron and the adsorbed oxygen close to the particle surface bond
together to form O2−. On the other hand, the valence band hole (h+) also moves to the particle surface. Water
close to the particle surface is dissociated by the polarity of titanium dioxide, to produce H+ and OH−. OH−
reacts with the hole (h+) to produce an HO radical. H+ reacts with O2− to produce an HO2 radical. These free
radicals act on the decomposition of organic media. It is understood that titanium dioxide acts as a catalyst
because when these free radicals are produced, titanium dioxide itself does not change at all.
The photocatalytic action is a negative factor in durability. A positive factor of titanium dioxide, however,
is its ultraviolet screening effect, described below. Because titanium dioxide has an ultraviolet absorbing
ability, ultraviolet light incident on the coating is absorbed by the titanium dioxide. Ultraviolet deterioration
of organic media is thereby relaxed. Uniformly dispersed titanium dioxide particles have a greater ultraviolet
screening effect because they produce a large ultraviolet absorption area. If organic media itself have inferior
durability, the ultraviolet screening effect is remarkable.
In general, it is believed that the anatase-type titanium dioxide has a higher photocatalytic ability than the
rutile type. From the difference in the Ti-O-Ti bond angle between anatase and rutile, it is judged that the
anatase-type crystal has higher hole mobility than the rutile type, and that in anatase-type titanium dioxide,
the hole moves to the particle surface more rapidly. Because the anatase type has a higher band gap (3.23 eV
= 383.7 nm) than the rutile type (3.02 eV = 410.4 nm), the produced electron and hole have such high energy
that recombination is difficult.*
* Yutaka Kubokawa, Ken'ichi Honda, Yasukazu Saito: Photocatalysis, Asakura Publishing Co., Ltd. (1988)
33
Figure 32. Photocatalytic action mechanism
Ａｔｔａｃｋ
Resin
Ａｔｔａｃｋ
Figure 33 shows the photocatalytic action of Tipaque titanium dioxide against the autoxidation of tetralin
(C10H12) irradiated with ultraviolet light. The greater the oxygen (O2) pressure change, the greater the
photocatalytic action. The test results reveal that anatase-type titanium dioxide has a greater photocatalytic
ability than the rutile type, and facilitates the autoxidation of tetralin. The rutile-type titanium dioxide
inhibits the autoxidation of tetralin, because the rutile type has less photocatalytic ability than the anatase
type and has the ultraviolet absorbing power. It is found that the photocatalytic action varies depending on
the surface treatment method and agent employed. One method of inhibiting the photocatalytic action
through surface treatment will be described in the next section.
Figure 33. Photocatalytic action of Tipaque titanium dioxide against tetralin autoxidation
(Autoxidation reaction of tetralin)
34
Brand
Crystal Form Surface Treatment
A-100
Anatase
－
A-220
Anatase
Al
CR-50
Rutile
Al
CR-80
Rutile
Al, porous-Si
CR-90
Rutile
Al, dense-Si
3-7-2 Imparting durability
As described in the previous section, titanium dioxide has photocatalytic ability. If an organic medium that
contain titanium dioxide is irradiated with ultraviolet light, the titanium dioxide acts on decomposition of the
organic medium. To inhibit the photocatalytic action of titanium dioxide, and to improve durability, generally,
the following methods are used:
1) Treating titanium dioxide particle surfaces with Al2O3, SiO2, ZrO2, or other hydrous oxide; and
2) Doping the titanium dioxide crystal lattice with traces of Al, Zn, and other dissimilar metals.
Treating titanium dioxide particle surfaces with Al2O3 and SiO2 prevents titanium dioxide particle cores
and the organic medium from directly touching each other. Free radicals are produced on the titanium
dioxide particle surface; however, when passing through the surface treatment layer, they decompose and
decrease. Deterioration of the organic medium is thereby inhibited. SiO2 surface treatment produces a greater
inhibiting effect than Al2O3 surface treatment. Of the SiO2 surface treatment methods, porous surface
treatment and dense surface treatment significantly differ in effectiveness. The denser the surface treatment
layer, the better the durability. Even a small quantity of surface treatment agent ZrO2 greatly improves
durability. It is hypothesized that when an electron (e−) and a hole (h+) are internally produced by ultraviolet
absorption, and move to the particle surface, ZrO2 facilitates recombination of the electron (e−) and hole (h+).
The production of free radicals is thereby reduced, and deterioration of the organic medium is inhibited.
It can be assumed that doping the titanium dioxide crystal lattice with Al, Zn or other dissimilar metal
produces functions as an electron (e−) acceptor and a recombination center of the electron (e−) and hole (h+),
leading to improved durability.
Figure 34 (chloride-processed brand) and Figure 35 (sulfate-processed brand) show the weather exposure
test results of different surface treatment agent Tipaque titanium dioxides in the solvent-type alkyd/melamine
resin paint system. It can be verified that durability varies depending on the surface treatment agent, quantity,
and state employed.
35
Figure 34. Weather exposure test results (chloride-processed brand)
100
90
UT771
60゜-60゜ Gloss
80
70
CR-50
CR-90
CR-80
60
CR-97
CR-57
50
CR-Super70
40
30
Alkyd/melamine resin paint system
Pigment concentration: P/B = 1/1
Alkyd/melamine = 7/3 (wt/wt)
Exposure site: Kishu (Mie Pref., Japan)
20
10
0
0
5
10
15
20
25
Exposure months
Brand
Crystal Form
Particle Size
Surface Treatment
UT771
Rutile
Medium
Al, Zr, Polyol
CR-Super70
Rutile
Medium
Al, Zr, Polyol
CR-97
Rutile
Medium
Al, Zr
CR-57
Rutile
Medium
Al, Zr, Polyol
CR-50
Rutile
Medium
Al
CR-80
Rutile
Medium
Al, porous-Si
CR-90
Rutile
Medium
Al, dense-Si
* ZrO2 surface treatment quantity
UT771 > CR-97 > CR-Super70 > CR-57
36
30
35
Figure 35. Weather exposure test results (sulfate-processed brand)
100
Alkyd/melamine resin paint system
Pigment concentration: P/B = 1/1
Alkyd/melamine = 7/3 (wt/wt)
Exposure site: Kishu (Mie Pref., Japan)
90
60゜-60゜ Gloss
80
70
R-630
60
R-980
R-930
50
40
A-220
30
20
10
0
0
5
10
15
20
25
30
35
Exposure months
Brand
Crystal Form Particle Size Surface Treatment
R-980
Rutile
Medium
Al* ,Al, Polyol
R-930
Rutile
Medium
Zn*, Al
R-630
Rutile
Medium
Al
A-220
Anatase
Small
Al
Doped with Al* and Zn*
Durability varies depending not only on the surface treatment agent and quantity but also on the particle
size and other factors. If products have the same filling quantity, the smaller the particle size, the larger the
photocatalytic active area; accordingly, durability decreases.
37
3-7-3 Resistance to discoloration
We often receive inquiries regarding the discoloration of organic media that contain titanium dioxide. This
section describes typical discoloration. In general, discoloration is caused by the structural change of other
substances due to the photocatalytic action of titanium dioxide. In common usage, titanium dioxide itself
does not discolor.
(Graying of rigid PVC mixed with lead stabilizer)
Rigid PVC (polyvinyl chloride plastic) is used in pipes, window frames, and other materials, and contains
a stabilizer for inhibiting resin deterioration. If lead stabilizer is selected from various stabilizers, when
exposed to sunlight, rigid PVC surfaces may discolor to gray color. Such graying is attributable to the
photocatalytic action of titanium dioxide contained in the PVC resin, and may be expressed as the following
mechanism:
(1) 2TiO2 -> Ti2O3 + O
(2) Ti2O3 + PbO -> 2TiO2 + Pb (black)
Figure 36 reveals that tribasic lead sulfate (3PbO·PbSO4) mixed with titanium dioxide has collapsed
because of the ultraviolet irradiation. After ultraviolet irradiation, the metallic Pb peak is observed with an
X-ray diffraction device, as shown in Figure 37.
Figure 36. Collapse of lead stabilizer (TEM micrograph before and after ultraviolet irradiation)
(Before ultraviolet irradiation)
(After ultraviolet irradiation)
38
Figure 37. X-Ray diffraction peak
(Before exposure)
(After exposure)
46.0
47.0
Pb (metallic) peak
48.0
To inhibit graying, it is necessary to use a titanium dioxide product with excellent durability as described
in the previous section, because graying is attributable to the photocatalytic action of titanium dioxide.
(Yellowing of polyethylene resin mixed with phenolic antioxidant)
Polyethylene resin antioxidants include phenolic compounds, sulfuric compounds, and phosphoric acid
compounds. As a typical phenolic antioxidant, BHT (2,6-ditertiary-butyl-4-methylphenol) is used.
During polyethylene resin oxidative destruction, free radicals are acquired by the BHT additive, and resin
oxidative destruction is thereby inhibited. If mixed with titanium dioxide, BHT may yellow, probably
because the reaction shown in Figure 38 occurs to produce quinone, which is yellow dimer of BHT. The
photocatalytic action of titanium dioxide promotes this reaction.
Figure 38. Yellowing mechanism of BHT
BHT (colorless)
Stilbene quinone (yellow)
39
Figure 39 shows the yellowing resistance test results of LDPE (low-density polyethylene) resin that
contains BHT, and is mixed with each of various Tipaque titanium dioxide products.
Figure 39. Comparison of yellowing resistance of Tipaque titanium dioxides
CR-60
CR-60-2
CR-63
CR-50
LDPE/BHT/TiO2=100/0.3/5
Irradiation with black light: 15 days
CR-80
0
Brand
2
4
6
8
10
12
Color Difference (Δb)
14
16
Crystal Form Particle Size Surface Treatment
CR-60
Rutile
Small
Al
CR-60-2
Rutile
Small
Al, Polyol
CR-63
Rutile
Small
Traces of Al, traces of Si, siloxane
CR-50
Rutile
Medium
Al
CR-80
Rutile
Medium
Al, porous-Si
To improve the yellowing resistance of this system, the user would select a brand that has particle surfaces
treated with an inorganic substance, especially SiO2, which produces a great photocatalytic action inhibiting
effect. Because siloxane-based organic compounds produce a photocatalytic action inhibiting effect, such
compounds contribute to improving yellowing resistance, even if particle surfaces are treated with a small
quantity of inorganic agent, as with CR-63.
To inhibit discoloration of this system by factors other than titanium dioxide, the use of metallic soap and
the combination of phenolic antioxidant with phenolic antioxidant are regarded as effective.
40
4. Standards of Titanium Dioxide Pigments
Titanium dioxide pigments are classified, as shown in Table 16, according to the crystal form and surface
treatment composition. As shown in Attached Table 5 (List of Tipaque Brands), Tipaque brands correspond
to the classified items of these standards.
Table 16. Standards of titanium dioxides
JIS K 5116 Classification
Item
Crystal Lattice Plane Spacing d*
Titanium Dioxide (TiO2)
(% by weight)
105°C volatile matter at deriver
(% by weight)
Water-soluble matter
(% by weight)
Anatase Type
Ａ１
Ａ２
Main peak observed at
0.352 nm.
Type
Ｒ１
Rutile Type
Ｒ２
Ｒ３
Main peak observed at 0.325 nm.
>=98
>=92
>=97
0.1<=
0.1<=
0.1<=
Agreement between
parties
0.6<=
0.5<=
0.6<=
0.5<=
Screen residue (>=45μm)
(% by weight)
>=90
>=80
0.7<=
0.1<=
Crystal lattice plane spacing d*
If measured with CuK alpha rays (λ = 0.15418 nm), the main peaks are observed
in X-ray diffraction graphs as follows:
Anatase-type titanium dioxide: 2θ = 25.3°
Rutile-type titanium dioxide: 2θ = 27.5°
Classification of Titanium Dioxide according to ASTM
ASTM D 476-00 Standard Classification for Dry Pigmentary Titanium Dioxide Products
Classificatio Crystal
Chalking Typical end use application(s)
Titanium Specific
resistance,
n Type
type
resistance
dioxide
min., Ω
,relative
(TiO2)
content,
min., %
free
white exterior house paint and Interior use
Ⅰ
anatase
94
5000
chalking
lowlow-medium % PVC
Ⅱ
rutile
92
5000
medium
medium high % PVC
Ⅲ
rutile
80
3000
Ⅳ
rutile
Ⅴ
rutile
Ⅵ
rutile
Ⅶ
rutile
ASTM
Standards
D3720
high
exterior coatings requiring excellent
durability
high
exterior coatings requiring excellent
durability with high gloss
medium- int-ext coatings, medium-high % PVC
high
medium- int-ext coatings, low-high % PVC
high
41
Moisture
content as
packed,
min., %
Specific
gravity
45-μm
screen
residue,
max., %
0.7
3.8 - 4.3
0.1
0.7
4.0 - 4.3
0.1
1.5
3.6 - 4.3
0.1
80
3000
1.5
3.6 - 4.3
0.1
90
3000
1
3.6 - 4.3
0.1
90
5000
0.7
3.6 - 4.3
0.1
92
5000
0.7
3.6 - 4.3
0.1
D1394
D2448
D280
D153
D185
5. Attached Table (List of Tipaque Brands)
Sulfate-processed Tipaque titanium dioxides
Anatase
Rutile
Brand
Ｒ－８２０
Ｒ－８３０
Ｒ－９３０
Ｒ－９８０
Ｒ－５５０
Ｒ－６３０
Ｒ－６８０
Ｒ－６７０
Ｒ－５８０
Ｒ－７８０
Ｒ－７８０-２
Ｒ－８５０
Ｒ－８５５
Ａ－１００
Ａ－２２０
Ｗ－１０
TiO2
（％）
Major Treatment
Agent
Particle Size
Avg. Particle
Size（μm）
Specific
Gravity
９３
９３
９３
９３
９４
９４
９５
９３
９４
８８
８０
９０
９０
９８
９６
９８
Ａｌ，Ｓｉ，Ｚｎ*
Ａｌ，Ｓｉ，Ｚｎ*
Ａｌ，Ｚｎ*
Ａｌ，polyol
Ａｌ，Ｓｉ
Ａｌ
Ａｌ
Ａｌ
Ａｌ
Ａｌ，Ｓｉ
Ａｌ，Ｓｉ
Ａｌ，Ｓｉ
Ａｌ，Ｓｉ
－
Ａｌ
－
Medium
Medium
Medium
Medium
Medium
Medium
Small
Small
Large
Medium
Medium
Medium
Medium
Small
Small
Small
0.26
0.25
0.25
0.24
0.24
0.24
0.21
0.21
0.28
0.24
0.24
0.24
0.26
0.15
0.16
0.15
4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.0
3.8
4.0
4.0
3.9
3.9
3.9
Specific
Bulk Specific
Oil
Surface Area
gravit
Absorption
（m2/g）
（g/cm3）
24
21
19
19
23
19
19
22
19
33
40
30
30
22
21
26
15
13
16
15
14
15
10
19
11
17
34
12
19
11
12
11
0.57
0.65
0.66
0.64
0.64
0.70
0.65
0.65
0.65
0.53
0.41
0.55
0.45
0.51
0.54
0.53
JIS K 5116
Classification
ASTM D-476
Classification
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　３
Ｒ　３
Ｒ　２
Ｒ　２
Ａ　１
Ａ　２
Ａ　１
Ⅶ
Ⅶ
Ⅶ
Ⅶ
Ⅱ
Ⅱ
Ⅱ
Ⅱ
Ⅵ
Ⅲ
Ⅲ
Ⅳ
Ⅳ
Ⅰ
Ⅰ
Ⅰ
JIS K 5116
Classification
ASTM D-476
Classification
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　１
Ｒ　２
Ｒ　２
Ｒ　２
Ｒ　３
Ⅴ
Ⅶ
Ⅱ
Ⅱ
Ⅶ
Ⅶ
Ⅴ
Ⅴ
Ⅴ
Ⅴ
Ⅴ
Ⅴ
Ⅱ
Ⅱ
Ⅱ
Ⅱ
Ⅵ
Ⅵ
Ⅳ
* Calcination agent
Chloride-processed Tipaque titanium dioxides
Rutile
Brand
ＵＴ７７１
ＣＲ－Ｓｕｐｅｒ７０
ＣＲ－５０
ＣＲ－５０-２
ＣＲ－５７
ＣＲ－８０
ＣＲ－９０
ＣＲ－９０-２
ＣＲ－９３
ＣＲ－９５
ＣＲ－９５３
ＣＲ－９７
ＣＲ－６０
ＣＲ－６０-２
ＣＲ－６３
ＣＲ－６７
ＣＲ－５８
ＣＲ－５８-２
ＣＲ－８５
TiO2
（％）
Major Treatment
Agent
Particle Size
Avg. Particle
Size（μm）
Specific
Gravity
９３
９５
９５
９５
９５
９３
９０
９０
９０
９０
９０
９３
９５
９５
９７
９２
９３
９３
８８
Ａｌ，Ｚｒ，polyol
Ａｌ，Ｚｒ，polyol
Ａｌ
Ａｌ，polyol
Ａｌ，Ｚｒ，polyol
Ａｌ，Ｓｉ
Ａｌ，d-Ｓｉ
Ａｌ，d-Ｓｉ，polyol
Ａｌ，d-Ｓｉ
Ａｌ，d-Ｓｉ，polyol
Ａｌ，d-Ｓｉ，amine
Ａｌ，Ｚｒ
Ａｌ
Ａｌ，polyol
Ａｌ，Ｓｉ，siloxane
Ａｌ
Ａｌ
Ａｌ，polyol
Ａｌ，Ｓｉ
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Large
Large
Large
Medium
Small
Small
Small
Small
Large
Large
Medium
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.28
0.28
0.28
0.25
0.21
0.21
0.21
0.21
0.28
0.28
0.25
4.2
4.2
4.2
4.2
4.2
4.1
4.0
4.0
4.0
4.0
4.0
4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.0
42
Bulk Specific
Specific
Oil
gravit
Surface Area
Absorption
（g/cm3）
（m2/g）
17
16
18
17
17
20
21
20
20
17
17
19
15
14
14
18
19
18
30
12
11
14
14
15
10
13
12
11
13
12
14
10
10
10
15
16
15
12
0.78
0.80
0.65
0.70
0.70
0.63
0.62
0.70
0.64
0.75
0.76
0.60
0.60
0.65
0.90
0.62
0.65
0.72
0.52
6. Tipaque Brands and Their Uses
Application Fields
Paints
Paper
◎
○
○
○
○
○
○
◎
◎
◎
○
×
×
×
×
×
×
×
×
◎
◎
×
×
×
×
◎
◎
×
×
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
◎
○
◎
◎
◎
◎
◎
◎
◎
◎
○
○
◎
◎
○
◎
◎
◎
◎
◎
◎
◎
○
○
○
◎
○
◎
◎
◎
◎
◎
◎
◎
◎
○
○
○
○
◎
×
×
○
○
○
○
○
○
○
◎
○
◎
◎
○
◎
◎
◎
◎
◎
◎
◎
◎
○
◎
◎
◎
◎
○
○
○
○
○
◎
◎
◎
○
○
○
○
○
◎
◎
◎
◎
◎
◎
◎
◎
◎
○
○
○
○
◎
◎
◎
◎ Optimum ○ Suitable × Not suitable
Titanium dioxide pigment concentration and application fields
0.12
0.25
0.5
1.23
4.8
9.1
20
33
50
56
60
67
71
75
80
0.5
1.0
2.0
5.0
10
25
50
100
125
150
200
250
300
400
7.5
5.7
4.3
P/B
2.4
5.9
11.1
20.0
23.8
27.3
33.3
38.5
42.9
50
0.05/1 0.01/1 0.25/1 0.5/1 1/1
1.25/1 1.5/1 2/1
2.5/1 3/1
4/1
2.9
0.46
0.24
0.14
2.1
1.3
0.88
0.55
0.39
0.30
0.20
(Q/D)
Plastics
Usage
○
◎
◎
◎
◎
PWC(%)
Distance between
particles
◎
○
◎
Attached Table 1
PHR
×
×
○
◎
○
◎
◎
◎
◎
◎
×
×
* Note : Grades with excellent durability are recommended because rigid PVC mixed with lead (Pb) stabilizer may discolor.
PVC(%)
Glass, Ceramics
○
○
◎
Rubber
○
○
○
◎
◎
◎
Engineering Plastics
◎
○
ABS
○
○
○
○
○
◎
○
Polyolefin (PE, PP, PS)
◎
◎
◎
○
○
Flexible Polyvinyl Chloride (for general purpose)
◎
○
Other
Rigid Polyvinyl Chloride (for building materials)
* Note
○
Plastics
Flexographic Ink
○
Gravure (for surface printing ink)
○
Metal Coating Ink
○
◎
◎
Gravure (for lamination ink)
○
○
○
Inks
Paper Lamination
○
○
○
Paper
Coated Paper
Powder Coating
Flat Emulsion Paint (for general purpose)
Flat Emulsion Paint (for high hiding power)
Gloss Emulsion Paint
Acrylate/Urethane Paint (for interior use)
Acrylate/Urethane Paint (for exterior use)
Water-soluble Resin Paint (for interior use)
Water-soluble Resin Paint (for exterior use)
ＵＴ７７１
ＣＲ－Super７０
ＣＲ－５０
ＣＲ－５０-２
ＣＲ－５７
ＣＲ－８０
ＣＲ－９０
ＣＲ－９０-２
ＣＲ－９３
ＣＲ－９５
ＣＲ－９５３
ＣＲ－９７
ＣＲ－６０
ＣＲ－６０-２
ＣＲ－６３
ＣＲ－６７
ＣＲ－５８
ＣＲ－５８-２
ＣＲ－８５
Automobile Top Coating Paint
Chlorideprocessed Titanium
Dioxide
◎
◎
◎
◎
Synthetic Resin Paint (for interior use)
銘柄
Ｒ－８２０
Ｒ－８３０
Ｒ－９３０
Ｒ－９８０
Ｒ－５５０
Ｒ－６３０
Ｒ－６８０
Ｒ－６７０
Ｒ－５８０
Ｒ－７８０
Ｒ－７８０-２
Ｒ－８５０
Ｒ－８５５
Ａ－１００
Ａ－２２０
Ｗ－１０
Sulfate-processed
Titanium Dioxide
Synthetic Resin Paint (for exterior use)
Usage
Paint
Metal Coating ink
PVC : Pigment Volume Concentration
Gravure ink
PWC : Pigment Weight Concentration
PHR : Parts per Hundred Resin
1/3
P/B : Pigment / Binder (ratio by weight)
Q/D = ( 0.74
)
-1
PVC
(Rhombohedral Packing)
Note : Specific gravity (TiO2 Pig) = 4.0g / cm3
Specific gravity (resin) = 1.0g / cm3
Q: Distance between particles. D: Particle size
43
TAIPAQUE is the trademark of titanium dioxide products manufactured by
Ishihara Sangyo Kaisha, Ltd. (ISK).
TAIPAQUE® features stable and superb quality, achieved with
ISK’s most advanced technology.
Ishihara Sangyo Kaisha, Ltd.
Head Office:
1-3-15 Edobori, Nishi-ku, Osaka 550-0002
Tel: 06-6444-1453
Tokyo Head Office:
2-10-30 Fujimi, Chiyoda-ku, Tokyo 102-0071
Tel: 03-3230-8629
Chubu Branch:
1 Ishihara-cho, Yokkaichi, Mie 510-0842
Tel: 059-345-6111
Fukuoka Sales Office:
5-10-11 Tenjin, Chuo-ku, Fukuoka 810-0001
Tel: 092-751-0431
Yokkaichi Plant:
1 Ishihara-cho, Yokkaichi, Mie 510-0842
Tel: 059-345-6111
Inorganic Chemicals
Engineering Division:
1 Ishihara-cho, Yokkaichi, Mie 510-0842
Tel: 059-345-6130
44
2005.2 作成