Title of Invention

A PROCESS FOR PREPARING A TITANIUM DIOXIDE DISPERSION

Abstract This invention relates to a process for preparing a titanium dioxide dispersion, comprising: pretreating a plurality of titanium dioxide particles with a metal oxide; dispersing a plurality of titanium dioxide particles and a dispersant in a first dispersion medium; preparing a nanoparticle pigment; mixing the nanoparticle pigment and the first dispersion medium containing the titanium dioxide; and interacting the first dispersion medium, nanoparticle pigment and the titanium dioxide to form an intervening dispersion of a plurality of nanoparticles around the titanium dioxide particles.
Full Text WO 2006/023O65 PCT/US2005/022677
IMPROVED PIGMENT SPACING
FIELD OF THE INVENTION
[0001] The present invention is generally related to controlling pigment spacing in a coating composition. More particularly, the present invention is related to achieving an improved TiO2 spacing in a paint, such as by using nanoparticles of ZnO, SiO2, or A12O3 of differing size and density distribution.
BACKGROUND OF THE INVENTION
[0002] Pigments such as titanium dioxide are a common component of coating compositions, particularly paint. Paint generally comprises a film-forming material or binder, a pigment, and a earner or solvent which evaporates to leave the solids as a coating on a substrate.
[0003] The pigment is generally partially or wholly suspended or dissolved in the carrier. Film formation of paint occurs when the paint is applied to a substrate and the carrier evaporates. During this process, the particles of pigment and binder come closer together. As the last vestiges of liquid evaporate, capillary action draws the binder particles together with great force, causing them to fuse and bind the pigment into a continuous film. This process is often referred to as coalescence.
[0004] Thus, the spacing and orientation in the carrier of the pigment particles relative to each other, and the various other solids, is essentially retained when the solid film is formed on the substrate. Flocculation and settling of the pigment phase are particularly undesirable. The pigments tend to cling together as packed pigment particles by agglomerating or clustering and then tend to resist subsequent redispersion by agitation, thus degrading the hiding power of the resulting paint. Hiding power is among one of the most important attributes of paint, and hiding power is determined particularly in white paint by the light scattering effectiveness of the pigment. The light scattering effectiveness of the pigment is in turn highly dependent on the spacing arrangement of the pigment in the dried coating as well as the particle sizes. Many different methods are known in the art for affecting and controlling the sizes of the pigment particles; however, this has proven to be ineffective in controlling light scattering sufficiently.
[0005] The pigment which is most widely used in paint is titanium dioxide. However, titanium dioxide is relatively expensive in comparison to the costs of other components used
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in paint. As such, there is a need to maximize the beneficial aspects of titanium dioxide, while minimizing the amount used. Enhanced light scattering occurs when the titanium dioxide pigment particles have a diameter of about 200 to 300 run and are uniformly spaced about the same distance apart. Most commonly, particulate TiO2 in the range of lOOnm to 400nm is utilized in conventional paint.
[0006] Various techniques have been attempted and used in the art to promote an even spacing and distribution of the pigment in the coating. A number of pigments have been found to function as "extender" pigments, wherein the extended pigments are alleged to function in mechanically spacing the opacifying or "prime" pigments. However, the flocculation forces present during the drying of paint still result in the presence of clusters and floes of pigment particles. Thus, even if total deaggregation is accomplished in the dispersion process, a random distribution of pigment particles will not approach the theoretical optimum that an ideally spaced distribution would achieve. [0007] Regardless of the technique, prior art coatings do not achieve a level of opacity which approaches that predicted theoretically. Thus, there is a long felt need for further improvement, such as a more efficient packing arrangement of TiO? particles in a coating formed on a substrate.
SUMMARY OF THE INVENTION
[0008] The present invention provides methods and compositions for coatings wherein the TiOo particles exhibit improved spacing over conventional paint formulations. Without limiting the scope of the invention, it is believed that the nanoparticle-sized pigment particles (specifically nano-ZnO) have an affinity for the surface of pigmentary TiO? particles. It is therefore believed that the nano ZnO particles effectively are disposed around and associated with the TiO2 particle so that the efficiency of the TiO2 particles arrangement increases; i.e., the overall stability of TiO2 pigment particles on drying is improved, thus improving properties such as tint strength and hiding power (contrast ratio). It is believed that the nano ZnO particles are interacting with the TiO2 to form a more efficient dispersion. [0009] In one embodiment, a method is provided for producing a titanium dioxide particle dispersion having nano-particle pigments interacting with the titanium dioxide to provide for more efficient packing arrangement of the titanium dioxide. In a preferred embodiment, the present invention relates to a paint composition of titanium dioxide, and a nanoparticle pigment, such as ZnO, and also a binder and a dispersant, along with additives as known in
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the art for formulating paint. The nanoscale zinc oxide, silicone dioxide, and aluminum oxide provide for a more uniform dispersment of the titanium dioxide when the paint dries to form a coating on a substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010\ FIGURE 1 represents the ideal spacing of TiO2 particles;
[0011] FIGURE 2 is a representation of how T1O2 particles are spaced in a typical prior art
paint; and
[0012] FIGURE 3 is a representation of one embodiment of the present invention showing
nano ZnO particles in association with TiO2 particles.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] It is known that efficient spacing of TiO2 particles in a paint produces a paint that has improved tint strength and hiding power. However, in most paints, upon drying, the TiOi pigment particles agglomerate and thus reduce the efficiency of the TiO2 particles. This agglomeration of T1O2 particles yields paints that have lower tint strength and hiding power. [0014] It is believed in accordance with the principles of the present invention that the nanoparticle-sized pigment particles (specifically nano-ZnO) are uniformly distributed within the paint matrix. Through this uniform distribution of particles, higher tint strength and hiding power are observed. This uniform distribution is achieved through the interaction of the surface modified/treated of the TiO2 (as supplied by the T1O2 manufacturer) and nano particles. The TiO2 used in the paint has metal oxide surface treatment along with oligomeric/polymeric dispersant; which keeps the TiO2 particles from flocculating to a certain extent in the dry film. Addition of surface treated nano particles (treated in house with an oligomeric/polymeric dispersant) further enhances the spacing of T1O2. Typically, addition of untreated nano particles (ex. ZnO) to a paint would flocculate the T1O2 and make the paint useless. However, with the proper pretreatment of both TiO2 and nano particles, electro-steric interactions prevent flocculation from occurring in the wet paint and during the paint drying process. By preventing the particles from flocculating, optimal TiO? spacing is achieved. Although prior art has shown some TiOi spacing with extender pigments, none has been known to produce as effective results.
[0015] The ideal spacing of TiO2 is illustrated in FIG. 1. The T1O2 particles are spaced as efficiently as can be, allowing for maximum scattering of light, and thus, providing the
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maximum hiding power. FIG. 2 illustrates what is believed to occur in current coating formulations. The particles are not spaced evenly (some are agglomerated); and therefore light scattering is not optimum and hiding power suffers. FIG. 3 illustrates one possible spacing arrangement in accordance with the principles of a preferred form of the present invention. It is believed that the nanoparticle-sized extender pigment particles, for example illustrated as ZnO, have an affinity for the surface of TiO2 particles that aides in spacing the TiO2 particles. Thus, the nanoparticles and TiC>2 interact by a mechanism resulting in improved spacing of the TiC>2 particles. Although both pigmentary and nano ZnO show improvements in tint strength (up to 30%); the nano ZnO particle effect is more efficient. Nano ZnO particles are also more efficient at improving hide. Although not ideal, the spacing in FIG. 3 has T1O2 particles which are still spaced better than in typical prior art paint systems; thus, the paint provides much improved hiding power. It must be appreciated that FIG. 3 is non-limiting, and that a multitude of various spacing arrangements and morphologies, providing improved spacing and resulting improved hiding power, are within the full scope of the present invention.
[0016] The positive attributes of nano ZnO particles in paints is resin system dependent, especially for tint strength and gloss observations. Thus, various resin systems can be used as known in the art. The most profound and preferred results are seen with acrylic resin systems (both self-crosslinking and non self-crosslinking). Contrast ratio increases are observed for all types of resin systems.
[0017] Similarly, various pigmentary TiO2 particles respond differently to the addition of nano ZnO particles. Thus, various pigmentary TiO2 particles can be used in accordance with the principles of the present invention. Commercial sample 1, a TiO2 product sold under the trade name Kronos 4311 by KRONOS Worldwide, Inc., located at 16825 Northcase Drive, Suite 1200, Houston, Texas 77210-4272, responds well in terms of tint strength and contrast ratio and is a preferred component. Commercial sample 3, sold under the trade name Tiona RCS-2 by Millennium Chemicals, Inc., located at 20 Wright Avenue, Suite 100, Hunt Valley, MD 21030, performs similarly, but it is not as efficient. Commercial sample 2, sold under the trade name Tiona 596S, also by Millennium Chemicals, Inc., located at 20 Wright Avenue, Suite 100, Hunt Valley, MD 21030, has only minimal improvements when compared to Commercial sample 1 and Commercial sample 3.
• Various dispersants may be used as known in the art.
• Additional TiO2 particle content in systems in accordance with the principles of the
present invention increases the tint strength (up to 40%); however, this improvement
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is not significant over paints without additional TiO2 particles. Hide is significantly improved with increasing TiO2 particle content. Thus, in one embodiment of the present invention, additional TiO: particle content is used as compared to conventional formulations.
EXAMPLES
[0018] A master batch of paint prepared in accordance with the principles of the present invention was made holding a portion of water. The batch was then apportioned, and the proper amounts of nanoparticles (see examples below) and water were post-added. Various components of the paint were varied depending on the focus of the experiment. Tint strength and contrast ratio of each sample were evaluated. Tables 1A-G list the basic formulation for Paints A-G, respectively. Table 1.
TABLE 1A
Paint A (High Gloss: Self-CrossJinking 100% Acrylic)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Self-Crosslinking Acrylic Polymer 48-52
TiO2 Slurry 31-35
Water 4-8
Ethylene Glycol 2-6
Associative High Shear Rheology Modifier 2-6
Alkyl Ester Coalescing Agent 1.5-3.5
Hydrophobic Copolymer Dispersant 0.5-2.0
Phosphated Co-ester Surfactant 0.1 -0.4
Mildewcide 0.1-0.4
Silicone Defoamer 0.1-0.3
Arnino Alcohol Additive 0.1 -0.3
Non-ionic HEUR Low Shear Rheology Modifier 0.1-0.3
Silicone Defoamer 0.1 -0.3
In-can Biocide 0.05-0.1
Silicone based Anti-mar Additive 0.05-0.1
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TABLE IB
Paint B (Semi-Gloss: 100% Acrylic - Low PVC)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Acrylic Polymer 37-41
TiO2 Slurry 27-31
Water 13-17
Opaque Polymer 4-8
Associative High Shear Rheology Modifier 2-6
Ethylene Glycol 1.5-4.5
Non-ionic HEUR Low Shear Rheology Modifier 0.5-2.5
Texanol 0.5-1.5
Hydrophobic Copolymer Dispersant 0.5-1.5
Feldspar (Nepheline Syenite) 0.2-0.8
Butyl Carbitol 0.2-0.8
Non-ionic Surfactant 0.2-0.8
Mildewcide 0.2-0.8
Attapulgite Clay 0.1-0.6
SiliconeDefoamer 0.1-0.4
Mineral Oil Defoamer 0.1 -0.4
In-can Biocide 0.05-0.2
TABLE 1C
Paint C (High Gloss - Styrene Acrylic)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Styrene-Acrylic Polymer 53-57
TiO2 Slurry 30-34
Butyl Carbitol 2-6
Ethylene Glycol 2-6
Associative High Shear Rheology Modifier 1-4
Texanol 1 -4
Water 1-4
Non-ionic Phosphate Ester Surfactant 0.2-0.6
Amino Alcohol Additive 0.2-0.6
Mildewcide 0.1-0.5
SiliconeDefoamer 0.1-0.5
Hydrophobic Copolymer Dispersant 0.1-0.5
In-can Biocide 0.05-0.15
Non-ionic HEUR Low Shear Rheology Modifier 0.05-0.15
Silicone based Anti-mar Additive 0.05-0.15
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TABLE ID
Paint D (Flat - PVA)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
TiO2 Slurry 24-28
Poly-vinyl Acrylic Emulsion 24-2S
Water 14-18
Calcined Kaolin 8-12
Opaque Polymer 7-11
Calcium Carbonate 3-6
Ethylene Glycol 1-4
Calcined Diatomaceous Earth 1-4
Non-ionic HEUR Low Shear Rheology Modifier 0.5-1.5
Associative High Shear Rheology Modifier 0.5-1.5
Mildewcide 0.2-0.6
Non-ionic Surfactant 0.2-0.6
Mineral Oil defoamer 0.2-0.6
Hydrophobic Copolymer Dispersant 0.2-0.6
Modified HEC (Modified Hydroxyethylcellulose) 0.2-0.6
Attapulgite Clay 0.2-0.6
Amino Alcohol Additive 0.2-0.6
In-can Biocide 0.05-0.25
TABLE IE
Paint E (Semi-gloss: VAE)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Vinyl Acetate-Ethylene Emulsion 38-42
TiO2 Slurry 34-38
Water 9-13
3% HEC 5-9
Propylene Glycol 1-4
Texano! 0.5-1.5
Hydrophobic Copolymer Dispersant 0.5-1.5
Mildewcide 0.5-1.5
Mineral Oil Defoamer 0.2-0.S
Amino Alcohol Additive 0.1-0.4
Phosphasted Co-ester Surfactant 0.1 -0.4
In-can Biocide 0.05-0.2
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TABLE IF
Paint F (Satin: 100% Acrylic - Mid PVC)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Acrylic Polymer 35-39
TiO2 Slurry 27-31
Water 11-15
Feldspar (Nepheline Syenite) 4-8
Opaque Polymer 4-8
Associative High Shear Rheology Modifier 2-4
Ethylene Glycol 2-4
Texanol 0.5-2
Non-ionic HEUR Low Shear Rheology Modifier 0.5-2
Mineral Oil Defoamer 0.3-1
Attapulgite Clay 0.3-1
Butyl Carbitol 0.3-1
Non-ionic Surfactant 0.3-1
Hydrophobic Copolymer Dispersant 0.2-0.8
Mildewcide 0.2-0.8
In-can Biocide 0.05-0.2
TABLE 1G
Paint G (Fiat: 100% Acrylic - High PVC)
A paint coating composition comprising of the following raw materials:
Generic Description wt% Range
Acrylic Polymer 28-32
TiO2 Slurry 22-26
Water 11-15
Calcined Kaolin 9-13
Feldspar (Nepheline Syenite) 7-10
Opaque Polymer 1.5-4
Calcium Carbonate 1.5-4
Associative High Shear Rheology Modifier 1 -3
Ethylene Glycol 1-3
Texanol 0.5-2
Hydrophobic Copolymer Dispersant 0.5-2
Non-ionic HEUR Low Shear Rheology Modifier 0.25-1
Mineral Oil Defoamer 0.25-1
Non-ionic Surfactant 0.2-0.8
Mildewcide 0.2-0.8
Attapulgite Clay 0.1-0.6
Amino Alcohol Additive 0.1 -0.6
In-can Biocide 0.05-0.2
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Example 1 - Nanoparticle Screening
[0019J The following nanoparticles were screened in a typical paint formulation: AI2O3, S1O2, and ZnO (two particle sizes) at two concentration levels, 0.50% and 1.00%. Particle sizes of these nanopigments ranged from -10-120 nm. TABLE 2 shows the data for the nanoparticle screening tests. The starting Paint A is any conventional white base paint with a PVC of-23.0. The concentration of nanoparticles is a percentage based on the total formula weight.
[0020J Three observations are noted from TABLE 2 first, all of the different nanoparticles studied yield an increase in tint strength and contrast ratio when formulated into Paint A (as opposed to Paint A without nanopigmentation). Second, improved tint strength and contrast ratio are observed with various particles sizes (-10-120 nm). Lastly, increasing the concentration of nanoparticles (0.5% vs. 1.0%) yields an increase in tint strength and contrast ratio. From this screening study, Paint A with added nano ZnO (-60 nm particle size) at a concentration of 0.5% yielded the highest increase in tint strength (28.75%) and contrast ratio (0.75%). One skilled the art would appreciate that while the contrast ratio increase is small, a mere increase of 0.40% will show a noticeable visual improvement in hiding power. Table 2.

Sample Nanoparticle Type Nanoparticle Size [Nanoparticle]* Tint Strength Increase Contrast Ratio Increase

Paint A AI2O3 -lOnrn 0.5% 2.40% 0.70%
1.0% 6.80% 0.40%

Paint A SiO2 -20 nm 0.5% 5.70% 0.65%
1.0% 14.50% 0.50%

Paint A ZnO -60 nm 0.5% 28.75% 0.75%
1.0% 22.70% 0.45%

Paint A ZnO -120 nm 0.5% 20.70% 0.35%
1.0% 27.10% 0.30%
*Based on total formula weight.
Example 2 - Nanoparticle Concentration Screening
[0021) In this study, the concentration range of nano ZnO (-60 nm particle size) was examined in Paint A. The concentrations of nano ZnO examined were 0.05%, 0.10%, 0.25%, 0.50%, 1.00%, 1.50%, 2.50%, and 5.00%. TABLE 3 shows the tint strength and contrast
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ratio data for increasing the nano ZnO concentration in Paint A. The concentration of nano ZnO is expressed as a percentage based on total formula weight.
[0022] The data in TABLE 3 illustrate that as the concentration of nano ZnO (particle size of-60 run) is increased in the base Paint A (0.05-5.00%), the tint strength and contrast ratio increase (as opposed to Paint A without nanopigmentation). The optimum use level of nano ZnO (particle size -60 ran) is 0.50%, yielding a tint strength increase of 28.75% and a contrast ratio of 0.75%. Table 3.

Sample Nanoparticle Type Nanoparticle Size [Nanoparticle]* Tint Strength Increase Contrast Ratio Increase

Paint A ZnO -60 nm 0.05% 1.50% 0.35%
0.10% 3.00% 0.30%
0.25% 14.10% 0.35%
0.50% 28.76% 0.75%
1.00% 22.70% 0.45%
1.50% 23.00% 0.40%
2.50% 20.70% 0.35%
5.00% 16.25% 0.20%
*Based on total formula weight.
Example 3 - Blending of Nanoparticles Study
[0023] This study examines the effect of blending nanoparticles of different composition and different particle sizes into a typical base paint formulation (Paint B in this case). The nanoparticles studied were ZnO (-60 nm and -120 nm particle size) and A12O3 (-50 nm particle size). TABLE 4 lists the contrast ratio results for Paint B with various added blends of nanopigmentation. The nanoparticles are examined alone, and then as the blends listed in TABLE 4. The concentration for each of the different nanoparticles was 0.50% based on total formula weight. The base Paint B is a conventional, well known paint with a PVC of -28.0.
[0024] TABLE 4 illustrates that when the nanoparticles are used alone or in blends of equal ratios in base Paint B, contrast ratio is increased (opposed to Paint B without nanopigmentation). This increase in contrast ratio is noted in all of the listed cases, whether the nanopigments are of approximately equal size (nano ZnO, ~60 nm blended with nano AI2O3, -50 nm) or are of different sizes (either nano ZnO, -60 nm blended with nano ZnO, -120 nm or nano AI2O3, ~50 nm blended with nano ZnO, -120 nm). In this study, the largest
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improvement in contrast ratio was observed, 0.55%, with the combination of the base Paint B with a blend of nano ZnO (-120 run) and nano A1?O3 (-50 nm). Table 4.

Sample Nanoparticle Type Nanoparticle Size [Nanoparticle]* Contrast Ratio Increase

Paint B ZnO -60 nm 0.50% 0.20%

Paint B ZnO -120 nm 0.50% 0.45%

Paint B A12O3 -50 nm 0.50% 0.40%

Paint B-Blend ZnO -60 nm 0.50% 0.35%
ZnO -120 run 0.50%

Paint B-Blend ZnO -60 nm 0.50% 0.20%
A12O3 -50 nm 0.50%

Paint B-Blend ZnO -120 nm 0.50% 0.55%
A12O3 -50 nm 0.50%
*Based on total formula weight.
Example 4 - Resin Type Screening with Nanoparticles
[0025] The following example demonstrates that the most common resin systems typically used in architectural coatings can be used with the nanotechnology described in this patent. The resin systems that were examined in this study were two acrylic resins (one self-crosslinking, one non self-crosslinking), a styrene-acrylic resin, a polyvinyl acrylic (PVA), and a vinyl acetate ethylene (VAE) resin. These commercially available resins were used to make up several conventional base paints as set forth in Table 1, Paint A (23.0 PVC), Paint B (28.0 PVC), Paint C (23.0 PVC), Paint D (51.75 PVC), and Paint E (27.64 PVC). All of these paints were examined with and without 0.50% (based on total formula weight) of nano ZnO (-60 nm particle size). TABLE 5 lists the tint strength and contrast ratio results for Paints A-E.
[0026] The data in TABLE 5 illustrates that the effect of spacing with nanoparticles (ZnO -60 nm in this case) is observed in paints made with different resin compositions. All of the various resin types, acrylic (self-crosslinking), acrylic (non self-crosslinking), styrene-acrylic,
PVA, and VAE in Paints A-E all show an improvement in tint strength and contrast ratio
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(over Paints A-E without nanopigmentation). The most dramatic improvement in tint strength and contrast ratio is observed with additions to base Paint A, which was formulated with a 100% self-crosslinking acrylic resin. Paint A, as modified, shows a 28.75% increase in tint strength and a 0.75% increase in contrast ratio. Table 5.

Sample Resin Type Nanoparticl e Type Nanoparticle Size [Nanoparticle]* Tint Strength Increase Contrast Ratio Increase

Paint A Acrylic ZnO -60 nm 0.50% 28.75% 0.75%
(Selfx-linking)

Paint B Acrylic ZnO ~60 nm 0.50% 13.20% 0.80%
(Non x-linking)

Paint C Styrene-Acrylic ZnO ~60 nm 0.50% 7.10% 0.30%

Paint D PVA ZnO -60 nm 0.50% 3.30% 0.20%

Paint E VAE ZnO ~60 nm 0.50% 3.80% 0.10%
*Based on total formula weight.
Example 5 - Pigmentary TiO2 Screening with Nanoparticles
[0027] This study examines several different commercially available pigmentary TiO? types and their ability to be spaced with nanoparticles (ZnO, -60 nm particle size in this case) as described in this patent. Three different pigmentary TiO2 products were studied as additives in base Paint A, with and without nanopigmentation (0.50% ZnO, based on total formula weight). The three different TiO^ products studied were Commercial-1, Commercial-2, and Commercial-3 previously described. TABLE 6 lists tint strength and contrast ratio data for these Paints.
[0028] The data in TABLE 6 illustrates that an improvement in tint strength and contrast ratio is observed in base Paint A, as modified, with all three commercially available pigmentary TiOa types. The largest improvement is noted in modified Paint A with TiO2 type Commercial-1, showing an increase in tint strength of 28.75% and contrast ratio increase of 0.75%.
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Table 6.

Sample TiO2 Nanoparticle Type Nanoparticle Size [Nanoparticle]* Tint Strength Increase Contrast Ratio Increase

Paint A Commercial 1 ZnO -60 nm 0.50% 27.80% 0.75%

Paint A Commercial2 ZnO -60 nm 0.50% 14.50% 0.55%

Paint A Commercial3 ZnO -60 run 0.50% 20.10% 0.65%

*Based on total formula weight.
Example 6 - Pigmentary TiO2 Concentration Screening with Nanoparticles
[0029] This example demonstrates that nanoparticles (ZnO, -60 nm in this case) can be used to effectively space various levels of pigmentary TiO2 in a typical architectural coatings formulation. Paint A was studied with various added levels of Commercial-1 TiO2; 7.10%, 10.70%, 14.20%, 17.80%, 21.10%, 24.90%, and 28.50% (based on total formula weight) with and without nanopigmentation (0.50% of nano ZnO, -60 nm). TABLE 6 lists the tint strength and contrast ratio data for these paints.
[0030J TABLE 7 illustrates that at every level of pigmentary TiO2 examined, an improvement in tint strength and contrast ratio is observed (as compared to the corresponding paint without nanopigmentation). The largest increase in tint strength and contrast ratio is observed with modified Paint A having 24.90% TiO2 (based on total formula weight) with
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Table 7.

Sample ITiO2]* (Commercial-1) Nanoparticle Type NanoparticleSize INanoparticle]* Tint Strength Increase Contrast Ratio Increase

Paint A 7.10% ZnO -60 ran 0.50% 10.00% 0.60%

Paint A 10.70% ZnO ~60 nm 0.50% 12.75% 0.60%

Paint A 14.20% ZnO -60 ran 0.50% 19.75% 0.55%

Paint A 17.80% ZnO -60 nm 0.50% 23.00% 0.65%

Paint A 21.10% ZnO -60 nm 0.50% 27.25% 0.35%

Paint A 24.90% ZnO -60 nm 0.50% 29.25% 0.90%

Paint A 28.50% ZnO -60 nm 0.50% 25.25% 0.40%
. — —
*Based on total formula weight.
Example 7 - PVC Variation with Nanopigmentation
[0031] This example demonstrates that nanoparticles (ZnO, ~60 nm in this case) can be used to effectively space pigmentary T1O2 in typical architectural paints of varying PVC. Paints of three different PVC's were examined in this study (all with the same resin and TiO2 types) at PVC's ranging from ~28.0-50.50 PVC. TABLE 8 lists the tint strength and contrast ratio improvements for these three paints.
[0032] TABLE 8 illustrates that for the PVC range of-28.0-50.50 PVC, an improvement in tint strength and contrast ratio is noted. The best improvement in this particular study was with modified Paint B (28.10 PVC) with tint strength improved by 5.50% and contrast ratio improved by 0.40%.
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Table 8.

Sample PVC Nanoparticle Type Nanoparticle Size [Nanoparticle|y' TintStrength Increase Contrast Ratio Increase

Taint B 28.10 ZnO -'50 nm 0 50% 5.50% 0.40%
1
Paint F 34.90 ZnO -60mn 0.50% 2.40% 0 45%

Paint G 50.40 ZnO ~60nm 0.50% 2.40% 0.50%
"Based on total formula weight.
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WHAT IS CLAIMED IS:
1 A process for preparing a titanium dioxide dispersion, comprising:
dispersing a plurality of titanium dioxide particles in a first dispersion medium;
preparing a nanoparticle pigment;
mixing the nanoparticle pigment and the first dispersion medium containing the titanium dioxide; and
interacting the nanoparticle pigment and the titanium dioxide to form an intervening dispersion of a plurality of nanoparticle pigment around the titanium dioxide particles.
2. The process of claim 1, wherein the nanoparticle pigment comprises zinc oxide.
3. The process of claim 1, wherein the step of dispersing titanium dioxide in a first
dispersion medium comprises using a dispersant selected from the group consisting of
ammonia salt hydrophobic copolymer dispersant and high molecular weight block
copolymer.
4. A coating on a substrate having improved coating properties, comprising:
a substrate; and
a coating having:
titanium dioxide particles; and nanoparticle pigment particles;
wherein the nanoparticle pigment particles interact with the titanium dioxide particles to provide a coating layer.
5. The coating of claim 4, wherein the nanoparticle pigment comprises zinc oxide.
6. The coating of claim 4, further comprising pigmentary-sized pigments.
7. The coating of claim 6, wherein the nanoparticle pigment comprises zinc oxide.
8 A paint composition comprising:
titanium dioxide;
a nanoparricle-sized pigment providing a substantially uniform distribution around the
titanium dioxide;
a dispersant; and
a binder.
9. The paint composition of claim 8, wherein the binder is selected from the group consisting of self-crosslinking 100% acrylic polymer, 100% acrylic polymers, and combinations thereof.
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10. The paint composition of claim 8, wherein the titanium dioxide is selected from the
group of titanium dioxide sold under the trademarks Tiona RCS-2, Kronos 4311, Tiona 596,
and mixtures thereof.
11. The paint composition of claim 8, wherein the nano-sized pigment comprises zinc
oxide.
12. The paint composition of claim 8, wherein the nano-sized pigment has a concentration
of about 0.5 to about 10.0 pounds per 100 gallons of the paint composition.
13. The paint composition of claim 12, wherein the nano-sized pigment has a
concentration of about 1.0 to about 10 pounds per 100 gallons of the paint composition.
14. The paint composition of claim 13, wherein the nano-sized pigment has a
concentration of about 2.5 to about 10.0 pounds per 100 gallons of the paint composition.
15. The paint composition of claim 14, wherein the nano-sized pigment has a
concentration of about 2.5 to about 5.0 pounds per 100 gallons of the paint composition.
16. The paint composition of claim 8, wherein the nano-sized pigment has a concentration
of about 4.0 to about 6.0 pounds per 100 gallons of the paint composition.
17. The paint composition of claim 8, wherein the nano-sized pigment has a concentration
of about 5.0 to about 7.0 pounds per 100 gallons of the paint composition.
18. The paint composition of claim 8, wherein the nano-sized pigment has a concentration
of about 0.5 to about 10.0 pounds per 100 gallons of the paint composition.
19. The paint composition of claim 8, wherein the dispersant has a concentration of
between about 0.5 and 2.5 pounds per 100 gallons of the paint composition.
20. The paint composition of claim 19, wherein the dispersant concentration is about 1
pound per 100 gallons of the paint composition.

This invention relates to a process for preparing a titanium dioxide dispersion, comprising: pretreating a plurality of titanium dioxide particles with a metal oxide; dispersing a plurality of titanium dioxide particles and a dispersant in a first dispersion medium; preparing a nanoparticle pigment; mixing the nanoparticle pigment and the first
dispersion medium containing the titanium dioxide; and interacting the first dispersion medium, nanoparticle pigment and the titanium
dioxide to form an intervening dispersion of a plurality of nanoparticles around the titanium dioxide particles.

Documents:

00353-kolnp-2007-assignment-1.1.pdf

00353-kolnp-2007-assignment.pdf

00353-kolnp-2007-correspondence-1.1.pdf

00353-kolnp-2007-correspondence-1.2.pdf

00353-kolnp-2007-form-18.pdf

00353-kolnp-2007-pct request.pdf

0353-kolnp-2007-abstract.pdf

0353-kolnp-2007-claims.pdf

0353-kolnp-2007-correspondence others.pdf

0353-kolnp-2007-description (complete).pdf

0353-kolnp-2007-drawings.pdf

0353-kolnp-2007-form1.pdf

0353-kolnp-2007-form2.pdf

0353-kolnp-2007-form3.pdf

0353-kolnp-2007-form5.pdf

0353-kolnp-2007-international publication.pdf

0353-kolnp-2007-international search authority report.pdf

353-kolnp-2007-abstract-1.1.pdf

353-kolnp-2007-claims-1.1.pdf

353-kolnp-2007-description (complete)-1.1.pdf

353-kolnp-2007-examination report reply.pdf

353-kolnp-2007-fer.pdf

353-kolnp-2007-for alteration of entry in the patent register.pdf

353-kolnp-2007-form-1-1.1.pdf

353-kolnp-2007-form-2-1.1.pdf

353-KOLNP-2007-FORM-26.pdf

353-KOLNP-2007-FORM-27-1.pdf

353-KOLNP-2007-FORM-27.pdf

353-kolnp-2007-form-3-1.1.pdf

353-kolnp-2007-form-5-1.1.pdf

353-kolnp-2007-petition under section 8(1).pdf

abstract-00353-kolnp-2007.jpg


Patent Number 241172
Indian Patent Application Number 353/KOLNP/2007
PG Journal Number 26/2010
Publication Date 25-Jun-2010
Grant Date 22-Jun-2010
Date of Filing 01-Feb-2007
Name of Patentee BEHR PROCESS CORPORATION
Applicant Address 3400 WEST SEGERSTROM AVENUE, SANTA ANA, CA 92704-6405
Inventors:
# Inventor's Name Inventor's Address
1 TARNG, MING-REN 20 ALCIRA, IRVIN, CA 92614
2 STEFFENHAGEN, MARK 1335 CITY LIGHTS DRIVE, ALISO VIEJO, CA 92656
3 FRIEDMAN, SHAUNE 2402 CALLE MONTECARLO, SAN CLEMENTE, CA 92672
4 CHU KIM 508 SOUTH ORANGE AVENUE #B, MONTEREY PARK, CA 91755
PCT International Classification Number C09C 1/36, C09C1/00
PCT International Application Number PCT/US2005/022677
PCT International Filing date 2005-06-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/914,594 2004-08-09 U.S.A.