U.S. patent application number 12/237736 was filed with the patent office on 2009-01-29 for ultrafine hydrous kaolin pigments, methods of making the pigments, and methods of using the pigments in gloss paint formulations.
Invention is credited to Kenneth W. Folmar, Ashok Khokhani, Sharad Mathur, Navin Patel.
Application Number | 20090025612 12/237736 |
Document ID | / |
Family ID | 35854284 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090025612 |
Kind Code |
A1 |
Patel; Navin ; et
al. |
January 29, 2009 |
Ultrafine Hydrous Kaolin Pigments, Methods of Making the Pigments,
and Methods of Using the Pigments in Gloss Paint Formulations
Abstract
Disclosed are methods of processing kaolin to produce ultrafine
hydrous kaolin. The methods involve processing gray crude kaolin by
subjecting the kaolin crude to flotation and then centrifuging the
kaolin to provide a fine stream that is subject to refinement. Also
disclosed are systems for the automated processing of gray crude
kaolin to produce the ultrafine hydrous kaolin and paint
compositions that contain the ultrafine hydrous kaolin.
Inventors: |
Patel; Navin; (Bridgewater,
NJ) ; Mathur; Sharad; (Macon, GA) ; Khokhani;
Ashok; (Manalapan, NJ) ; Folmar; Kenneth W.;
(Macon, GA) |
Correspondence
Address: |
BASF CATALYSTS LLC
100 CAMPUS DRIVE
FLORHAM PARK
NJ
07932
US
|
Family ID: |
35854284 |
Appl. No.: |
12/237736 |
Filed: |
September 25, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10926752 |
Aug 26, 2004 |
|
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12237736 |
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Current U.S.
Class: |
106/484 ;
106/486; 106/488 |
Current CPC
Class: |
B82Y 30/00 20130101;
C01P 2006/63 20130101; C01P 2006/64 20130101; C09C 1/42 20130101;
C01P 2006/12 20130101; C01P 2006/22 20130101; C01P 2006/62
20130101; C01P 2004/64 20130101; C01P 2004/62 20130101; C01P
2006/60 20130101; C01P 2004/51 20130101 |
Class at
Publication: |
106/484 ;
106/486; 106/488 |
International
Class: |
C04B 14/04 20060101
C04B014/04 |
Claims
1. A method of processing kaolin, comprising sequentially:
subjecting a kaolin crude comprising a super major amount of gray
kaolin to flotation to provide a kaolin having reduced titania
content; centrifuging the kaolin kaolin having reduced titania
content at high speeds to provide a coarse stream and fine stream,
the coarse stream comprising kaolin wherein at least about 70% by
weight has a size of 2 microns or less, the fine stream comprising
kaolin wherein at least about 80% by weight has a size of 1 micron
or less; and refining the fine stream into an ultrafine kaolin
pigment.
2. The method of claim 1, wherein centrifuging at high speeds
involves using "g" forces from about 1,000 to about 10,000.
3. The method of claim 1, wherein the kaolin crude comprises at
least about 75% by weight of gray kaolin.
4. The method of claim 1, wherein flotation reduces the titania
content of the kaolin to less than about 1% by weight.
5. The method of claim 1, wherein flotation comprises one of froth
flotation, ultraflotation, and TREP flotation.
6. The method of claim 1, further comprising degritting the kaolin
crude before subjecting the kaolin crude to flotation.
7. The method of claim 1 further comprising ozonating the kaolin
having a reduced titania content before centrifuging the kaolin,
ozonating comprising contacting the kaolin having a reduced titania
content with about 0.1 to about 20 pounds of ozone per ton of
kaolin.
8. The method of claim 1, wherein refining the fine stream
comprises at least two of flocculation, bleaching, filtering, and
drying.
9. The method of claim 1, wherein refining the fine stream
comprises at least three of flocculation, bleaching, filtering,
spray drying, and pulverization.
10. The method of claim 1, with the proviso that the method does
not comprise selective flocculation of the kaolin crude.
11. The method of claim 1 further comprising refining the coarse
stream into a coarse engineered kaolin pigment.
12. The method of claim 1, further comprising testing and
generating data of at least one parameter of at least one of the
kaolin crude, the kaolin having reduced titania content, the fine
stream, or ultrafine kaolin pigment or at least one parameter of
subjecting the kaolin crude to flotation and centrifuging the
kaolin at high speeds; and controlling operation of at least one of
subjecting the kaolin crude to flotation and centrifuging the
kaolin at high speeds based on data generated by the tester.
13-20. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to ultrafine kaolin
pigments, making ultrafine kaolin pigments from the gray crude
kaolin, and using the ultrafine kaolin pigments in paint
compositions.
BACKGROUND OF THE INVENTION
[0002] Kaolin is a fine usually white clay formed by the weathering
of aluminous minerals (as feldspar) and mainly consists of
kaolinite. Kaolinite is commonly represented by one or more of the
chemical formulae Al.sub.4Si.sub.4O.sub.10(OH).sub.8;
Al.sub.2O.sub.32SiO.sub.22H.sub.2O; and/or
Al.sub.2Si.sub.2O.sub.5(OH).sub.4. Kaolin is one of the many
industrial minerals mined today. Reserves are found in Georgia
(USA), Egypt, Brazil, United Kingdom, Queensland (Australia),
Korea, China, and Ukraine.
[0003] Generally speaking, kaolin from different countries, and
even different deposits within the same country, differs in many
respects due to variations in a number of kaolinite properties.
Examples of such properties include degree of crystallinity,
coarseness, brightness, levels of other compounds such as titania
and iron oxide, particle size, particle shape, size and/or shape
distribution. Variations in properties leads to differences in
performance of the resultant kaolin products. For example,
crystallinity impacts resultant brightness, whiteness, opacity,
gloss, and viscosity of the resultant products. It is noted that
opacity and gloss are application performance parameters while the
other listed parameters are pigment attribute parameters. Particle
size, shape, and distribution impacts the smoothness, optical
properties, and flow properties of the resultant products.
Smoothness and optical properties are application performance
parameters while flow properties are pigment attribute
parameters.
[0004] Kaolin based products are used in many applications
including paints, paper coatings, agricultural compositions,
fiberglass products, polymer and rubber compositions, ceramic
applications, catalyst supports, pharmaceuticals, cosmetics,
electrical components, adhesives, filter aids, and many more.
Certain grades of kaolin having discrete properties are ideally
suited for select applications. Accordingly, to maximize the
quality of a resultant kaolin grade, kaolin crude is subjected to
processing that yields a specifically desired grade of kaolin.
[0005] The paint industry supplies consumer-oriented products of
the solvent and emulsion types. Solvent or so-called "oil based"
paints are relatively simple systems, easy to formulate but
difficult for the consumer to use. Solvent paint contains a binder
(oil of resin), a solvent (thinner), drying agents and pigments.
Alkyd paint is the most common kind of oil based paint, and many
oil based paints are therefore normally referred to as alkyd
paints. Alkyd is simply the name of the synthetic resin, usually
containing a vegetable oil, that is used as the binder. Emulsion or
so-called "latex" paints are complex mixtures containing latex
surfactants, protective colloids, emulsifiers and water in addition
to one or more types of pigment. Following their introduction after
World War II, latex paints have substantially gained in market
acceptance. Latex paints now account for a majority of interior and
exterior paint trade sales.
[0006] Interior and exterior paints have generally similar
formulations. An important distinction, however, is that exterior
grade paints contain relatively more binder and prime pigment but
less extender pigment than interior paints. This is because paint
film integrity and overall durability are more critical in exterior
paints than in interior grades. Accordingly, improved pigments and
extender pigments are desired for exterior paints.
SUMMARY OF THE INVENTION
[0007] The following presents a simplified summary of the invention
in order to provide a basic understanding of some aspects of the
invention. This summary is not an extensive overview of the
invention. It is intended to neither identify key or critical
elements of the invention nor delineate the scope of the invention.
Rather, the sole purpose of this summary is to present some
concepts of the invention in a simplified form as a prelude to the
more detailed description that is presented hereinafter.
[0008] The present invention provides ultrafine kaolin pigments
that have at least one of high surface area, fine particle size
distribution, low oil absorption, and high GE brightness values.
Waste is mitigated when making the ultrafine kaolin pigments,
because selective flocculation is not performed on the crude kaolin
starting material. Moreover, unused coarse pigments produced as a
by-product while making the ultrafine kaolin pigments may be
advantageously used in paper coating applications. Due to the high
surface area, fine particle size distribution, low oil absorption,
and high GE brightness values of the ultrafine kaolin pigments,
they are ideally suited for paint formulations, especially gloss
paint compositions.
[0009] One aspect of the invention relates to methods
[0010] Another aspect of the invention relates to
[0011] To the accomplishment of the foregoing and related ends, the
invention comprises the features hereinafter fully described and
particularly pointed out in the claims. The following description
and the annexed drawings set forth in detail certain illustrative
aspects and implementations of the invention. These are indicative,
however, of but a few of the various ways in which the principles
of the invention may be employed. Other objects, advantages and
novel features of the invention will become apparent from the
following detailed description of the invention when considered in
conjunction with the drawings.
BRIEF SUMMARY OF THE DRAWINGS
[0012] FIG. 1 is a flow diagram of one aspect of a system and
method of processing kaolin in accordance with the present
invention.
[0013] FIG. 2 is a schematic diagram of another aspect of a system
for automated processing of kaolin in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The methods of the present invention enable the efficient
production of ultrafine hydrous kaolin from gray kaolin crude. The
ultrafine hydrous kaolin is advantageously employed in paint
compositions. The methods of the present invention also enable the
production of coarse engineered kaolin for paper applications as a
by product of making the ultrafine kaolin. Ultrafine kaolin
pigments are characterized by low oil absorption, high brightness,
high surface area, at least 96% by weight of the particles have a
size of about 1 micron or less, and at least 97% by weight of the
particles have a size of about 2 microns or less. Coarse engineered
kaolin pigments are characterized by low surface area, at least 80%
by weight of the particles have a size of about 2 microns or less,
and narrow particle size distribution.
[0015] The methods of the present invention involve subjecting gray
kaolin crude to floatation and then high speed centrifugation in a
sequential manner to provide the ultrafine kaolin. Degritting may
be optionally performed before flotation while ozonation may be
optionally performed after flotation and before high speed
centrifugation. In one embodiment, the gray kaolin crude or the
degritted gray kaolin crude is not subjected to selective
flocculation. Sequential means that flotation and centrifugation
are performed in the order listed, although optionally other acts
may be performed before, during and/or after the two sequential
acts (such as degritting and/or ozonation and/or refinement).
[0016] The kaolin crude that can be subjected to the methods of the
present invention contains a super-major amount of gray or hard
kaolin, optionally a minor amount of fine white kaolin, and
optionally small amounts of nonkaolin particles. Generally, gray
kaolins have a high iron content. Nonkaolin particles include
titania, quartz, various ferruginous minerals, mica, and
nonkaolinitic clays such as bentonite and attapulgite. Super-major
amounts include at least 75% by weight, minor amounts include less
than 50% by weight, and small amounts include less than 10% by
weight. In another embodiment, the kaolin crude contains at least
about 80% by weight of gray or hard kaolin and less than about 20%
by weight of fine white kaolin. In yet another embodiment, the
kaolin crude contains at least about 90% by weight of gray or hard
kaolin and less than about 10% by weight of fine white kaolin.
[0017] The kaolin crude contains particles wherein at least about
70% by weight have a particle size of about 2 microns or less, at
least about 30% by weight have a particle size of about 0.3 microns
or less, a titania content from about 1% to about 3% by weight, and
a surface area of at least about 18 m.sup.2/g. In another
embodiment, the kaolin crude contains particles wherein at least
about 80% by weight have a particle size of about 2 microns or
less, at least about 35% by weight have a particle size of about
0.3 microns or less, a titania content from about 1.5% to about
2.5% by weight, and a surface area of at least about 20
m.sup.2/g.
[0018] Prior to processing the kaolin crude, a slurry may be formed
by combining the kaolin crude with water, and optionally a
dispersant. One advantage to the present invention is that a
dispersant may not be required before an ultrafine stream of
hydrous kaolin is separated from coarse kaolin via high-speed
contrifugation. Thus, in one embodiment, a dispersant is not
employed until an ultrafine stream of hydrous kaolin is separated
from coarse kaolin via high-speed contrifugation.
[0019] The dispersant may be an organic dispersant or inorganic
dispersant. Inorganic dispersant typically include phosphate salts.
Examples of phosphate salts include inorganic polyphosphates and
pyrophosphates (which are actually a type of polyphosphate), such
as sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP)
and tetrasodium pyrophosphate (TSPP).
[0020] Organic dispersants typically include ammonia-based
dispersants, sulfonate dispersants, carboxylic acid dispersants,
and polymeric dispersants, such as polyacrylate dispersants, as
well as other organic dispersants conventionally employed in kaolin
pigment processing.
[0021] The kaolin crude is optionally subjected to degritting.
Kaolin crude occurs as an ore that may contain grit, grit composed
a relatively large particles. The grit is undesirable and thus is
removed. The resulting degritted crude kaolin is composed largely
of kaolin particles that usually have a wide range of sizes ranging
from slimes (finer than 0.3 microns) up to about 15 microns.
[0022] Degritting is performed in any conventional manner using one
or more of sieves, sandboxes, gravity settling, or hydrocyclones.
Either wet or dry degritting may be employed. For example,
degritting may be performed by combining the crude kaolin with
water and passing the slurried mixture through a sieve, such as a
325 mesh sieve or a 200 mesh sieve. Optionally, a clay dispersant
is also added to the slurry to provide additional fluidity to
facilitate the degritting process. Examples of clay dispersants
include ammonia-based dispersants, phosphate-based dispersants,
sulfonate dispersants, carboxylic acid dispersants, and polymeric
dispersants, such as polyacrylate dispersants, as well as other
organic dispersants employed in kaolin pigment processing. The
amount of dispersant used in the slurry is typically from about
0.01% to about 1% based on the weight of crude kaolin.
[0023] After degritting the crude kaolin, the resulting degritted
crude kaolin is subjected to flotation. Flotation serves to reduce
the titania content to less than about 1% by weight and/or reduce
the iron oxide content to less than about 1.5% by weight. In
another embodiment, flotation reduces the titania content to less
than about 0.7% by weight and/or reduce the iron oxide content to
less than about 1.25% by weight. In yet another embodiment,
flotation reduces the titania content to less than about 0.5% by
weight and/or reduce the iron oxide content to less than about 1%
by weight. In still yet another embodiment, flotation reduces the
titania content to less than about 0.4% by weight and/or reduce the
iron oxide content to less than about 0.75% by weight. The
degritted crude may be centrifuged prior to flotation to control
the particle size distribution such that the subsequent high speed
centrifuge operation results in desired coarse particle size
distribution that does not require a further centrifuge act.
[0024] Flotation is performed in any conventional manner including
wet flotation, ultraflotation, froth flotation, TREP flotation
(titania removal and extraction process), and the like. General
methods of flotation are described in Mathur, S., "Kaolin
Flotation", Journal of Colloid and Interface Science, 256, pp.
153-158, 2002, which is hereby incorporated by reference in this
regard. Ultraflotation involves using a particulate reagent with a
fatty acid and selected flotation oils to remove titania from a
slurry of impure clay. One characteristic of ultraflotation is that
the purified kaolin is recovered as a dilute slurry that is
subsequently dewatered. Froth flotation functions by separating
certain mineral particles from other particles in a slurry based on
differences in the mineral species. The processing generally
depends upon adding reagents that selectively attach to mineral
particles to be floated, whereby the particles with attached
reagent(s) have a greater affinity for air bubbles than other
particles and can be removed as a froth. TREP flotation involves
conditioning kaolin in a high intensity mill using a collector,
such as a fatty acid collector, tall oil collector, or an
hydroxamate collector, and a metal salt. This is followed by the
addition of a dispersant, such as an acrylate salt dispersant.
Optionally, magnetic separation or selective flocculation can also
be used for improving brightness stand alone or in conjunction with
flotation.
[0025] Flotation may be performed at any suitable solids content,
pH, and temperature using a slurry of the degritted kaolin crude
and water. In one embodiment, during flotation at least one of the
following parameters are satisfied: the solids content is from
about 10% to about 50%, the pH is from about 5 to about 11, and the
temperature is from about 10.degree. C. to about 90.degree. C. In
another embodiment, during flotation at least one of the following
parameters are satisfied: the solids content is from about 20% to
about 40%, the pH is from about 6 to about 10, and the temperature
is from about 20.degree. C. to about 60.degree. C.
[0026] In the methods of the present invention, selective
flocculation of kaolin crude is not required to provide the kaolin
crude with a discrete particle size/particle size distribution. In
selective flocculation, charged inorganic or organic molecules are
used to selectively flocculate minerals from each other based on
difference in mineral species. Selective flocculation of kaolin
crude in some instances may deleteriously affect the brightness
and/or viscosity of the resultant kaolin pigment. In one
embodiment, the methods of the present invention do not comprise
selective flocculation of the kaolin crude. In another embodiment,
the methods of the present invention do not comprise selective
flocculation of kaolin until after high-speed centrifugation
(discussed below). In yet another embodiment, the methods of the
present invention do not comprise delaminating kaolin crude.
[0027] After flotation, the kaolin undergoing processing is
optionally subjected to ozonation. Ozonation involves oxidative
bleaching, using ozone, in order to bleach components, such as
organic discolorants, that may be present. The ozone acts not only
to destroy substantial portions of discoloring organics, but also
destroys by oxidation the organic dispersant, if such a compound is
present. However, the ozone does not destroy inorganic
dispersants.
[0028] Ozonation is performed in any suitable manner. For example,
ozonation may be performed at a dosage level from about 0.1 to
about 20 pounds of ozone per ton of kaolin. In another embodiment,
ozonation is performed at a dosage level from about 0.5 to about 10
pounds of ozone per ton of kaolin. The ozone may be applied as a
stream of bubbles which can be passed upwardly through the slurry.
This can be a batch process or a continuous process in which the
ozone bubbles pass counter current to a flow of the slurry in a
pipe or other conduit, such as mixed and packed column.
[0029] After ozonation, the ozonated kaolin is subjected to
optional delamination. Delamination can involve wet milling, slurry
milling, wet grinding, and the like. Such delamination processes
involve the use of a grinding media and water. Kaolin is combined
with the grinding media and water to form a slurry and transported,
such as by pumping, through the delamination equipment. Typically,
the kaolin solids in the slurry during delamination is from about
5% to about 50% by weight.
[0030] After ozonation, high-speed centrifugation is employed to
separate the optionally ozonated kaolin into two streams. It is
noted that the high-speed centrifugation is performed after
flotation. Centrifugation separates the kaolin into a coarse stream
(at least about 70% by weight of the particles have a size of 2
microns or less) and a fine stream (at least about 80% by weight of
the particles have a size of 1 micron or less). In another
embodiment, the coarse stream has at least about 80% by weight of
the particles have a size of 2 microns or less and the fine stream
has at least about 85% by weight of the particles have a size of 1
micron or less. In yet another embodiment, the coarse stream has at
least about 90% by weight of the particles have a size of 2 microns
or less and the fine stream has at least about 90% by weight of the
particles have a size of 1 micron or less.
[0031] Although not wishing to be bound by any theory, it is
believed that usage of high-speed centrifuge to generate the
ultrafine particle size distribution also results in removal of
coloring impurities and thus increasing brightness of the product
in excess of about 91 GEB.
[0032] All particle sizes referred to herein are determined by a
conventional sedimentation technique using a Micromeretics, Inc.'s
SEDIGRAPH.RTM. 5100 analyzer analysis. The sizes, in microns, are
reported as "e.s.d." (equivalent spherical diameter). Particles are
slurried in water with a dispersant and pumped through the detector
with agitation to disperse loose agglomerates.
[0033] Centrifugation may be conducted more than once, but at least
one centrifugation treatment is a high-speed centrifugation
treatment. In a high-speed centrifugation treatment the centrifuge
may operate at "g" forces from above about 1,000 to about 10,000.
In another embodiment, the high-speed centrifugation treatment the
centrifuge may operate at "g" forces from about 2,000 to about
7,500. In yet another embodiment, the high-speed centrifugation
treatment the centrifuge may operate at "g" forces from above about
2,500 to about 5,000. Examples of centrifuges include Bird solid
bowl machines, high speed centrifuges, horizontal three-phase
centrifuges, and the like.
[0034] The fine stream is then subject to refining, which may
involve at least one of flocculation, bleaching, filtering, drying,
blending, and pulverizing to provide the ultrafine kaolin.
Flocculation involves separating minerals of one species from
minerals of the same species, e.g., the separation of ultrafine
kaolin particles from fine or coarse kaolin particles. Flocculation
is effected using an ionic material, such as an acid. Sulfuric acid
is an inexpensive and widely available acid.
[0035] Generally, bleaching involves increasing the brightness of
the kaolin. Bleaching involves contacting the coarse kaolin stream
with a suitable amount of one or more of hydrosulfite (dithionite)
salts, potassium permanganate, oxygen gas, alkali bichromates,
alkali chlorates, alkali chlorites, ammonium persulfate and soluble
peroxides such as sodium and hydrogen peroxide, sodium
hypochlorite, and the like.
[0036] Filtration can be employed to at least one of increase
solids content (for example increase solids content to about 55% or
higher) and to substantially remove particles larger than 2
microns. Increasing the solids content in some instances improves
the efficiency of a subsequent spray drying operation. Filtration
can be carried out in any suitable manner and is typically carried
out using rotary drum vacuum filters.
[0037] Drying, such as spray drying, the kaolin is performed to
reduce the moisture level of the kaolin. Drying the kaolin may
facilitate optional, subsequent pulverization acts. The kaolin is
dried by any suitable technique. Examples of drying kaolin include
spray drying, flash drying, rotary drying, or other conglomeration
techniques. These drying techniques are known in the clay industry.
In one embodiment, after drying the ultrafine kaolin has a moisture
level of less than about 1.5% by weight. In another embodiment,
after drying the ultrafine kaolin has a moisture level of less than
about 1% by weight. In yet another embodiment, after drying the
ultrafine kaolin has a moisture level of less than about 0.5% by
weight.
[0038] Blending involves combining the kaolin with other
particulate matter, such as a different batch of kaolin, titania,
other clays, calcium carbonate, calcined kaolin, and the like to
arrive at a mixture that has properties desired by the end user or
a subsequent user.
[0039] Pulverization may be conducted in any suitable manner. In
one embodiment, the ultrafine kaolin is pulverized in at least
once. In another embodiment, the ultrafine kaolin is pulverized in
at least two separate acts (twice pulverized). The pulverization
may break up any agglomerates that may be present. Such
agglomerates may form during drying, changing the particle size
achieved by high-speed centrifugation and other process acts.
[0040] The ultrafine kaolin pigment product has numerous desirable
properties. For example, the ultrafine kaolin pigment product has
one or more of at least about 97% by weight of the particles have a
size of 2 microns or less, at least about 96% by weight of the
particles have a size of 1 micron or less, at least about 89% by
weight of the particles have a size of 0.5 microns or less, at
least about 67% of the particles have a size of 0.3 microns or
less, a surface area of at least about 23 m.sup.2/g, about 0.75% by
weight or less of titania, about 1.5% by weight or less of iron
oxide, and brightness of about 91 or more. In another embodiment,
the ultrafine kaolin pigment product has one or more of at least
about 98% by weight of the particles have a size of 2 microns or
less, at least about 97% by weight of the particles have a size of
1 micron or less, at least about 90% by weight of the particles
have a size of 0.5 microns or less, at least about 70% of the
particles have a size of 0.3 microns or less, a surface area of at
least about 25 m.sup.2/g, about 0.5% by weight or less of titania,
about 1.25% by weight or less of iron oxide, and brightness greater
than 92. In yet another embodiment, the ultrafine kaolin pigment
product has one or more of at least about 99% by weight of the
particles have a size of 2 microns or less, at least about 98% by
weight of the particles have a size of 1 micron or less, at least
about 92% by weight of the particles have a size of 0.5 microns or
less, at least about 72% of the particles have a size of 0.3
microns or less, a surface area of at least about 26 m.sup.2/g,
about 0.4% by weight or less of titania, about 1% by weight or less
of iron oxide, and brightness of about 93 or more.
[0041] Surface area is determined by the art recognized BET method
using N.sub.2 as the adsorbate. Surface area alternatively is
determined using Gardner Coleman Oil Absorption Test is based on
ASTM D-1483-84 which measures grams of oil absorbed per 100 grams
of kaolin. Brightness measurements are performed using the TAPPI
standard method, T524, and are reported as "GE brightness" or "GEB
values".
[0042] The coarse stream is then subject to refining which may
involve at least one of bleaching, filtering, bulking, spray
drying, and blending. Blending involves combining the coarse kaolin
with other particulate matter, such as a different batch of kaolin,
titania, other clays, calcium carbonate, calcined kaolin, and the
like to arrive at a mixture that has properties desired by the end
user or a subsequent user.
[0043] The coarse kaolin pigment product has numerous desirable
properties that make it particularly useful in paper coating
applications. For example, the coarse kaolin pigment product has
one or more of at least about 95% by weight of the particles have a
size of 5 microns or less, at least about 80% by weight of the
particles have a size of 2 microns or less, at least about 20% by
weight of the particles have a size of 0.3 microns or less, a
surface area from about 14 to about 20 m.sup.2/g, about 1% by
weight or less of titania, about 1.5% by weight or less of iron
oxide, and a brightness of about 85 or more. In another embodiment,
the coarse kaolin pigment product has one or more of at least about
96% by weight of the particles have a size of 5 microns or less, at
least about 90% by weight of the particles have a size of 2 microns
or less, at least about 25% by weight of the particles have a size
of 0.3 microns or less, a surface area from about 15 to about 19
m.sup.2/g, about 0.75% by weight or less of titania, about 1.25% by
weight or less of iron oxide, and a brightness of about 87.5 or
more.
[0044] Generally speaking, one or more conventional clay processing
steps such as crushing, grinding, frationation, delamination,
magnetic separation, floc/filtration, heat treatment, and the like,
may be employed before or after the methods of the present
invention.
[0045] Crushing reduces kaolin rock to gravel; that is, kaolin rock
having diameters of less than about 10 cm in diameter. Grinding
involves processing crude kaolin to achieve a desired particle size
distribution. Grinding may be carried out by dry milling, dry ball
milling, dry grinding, and the like.
[0046] Kaolin contains naturally separated platy kaolin particles
as well as "booklets", which comprise stacks of kaolin platelets.
These stacks are concentrated in particles having a size of about 2
or more microns. Delamination of these booklets involves providing
impact energy which is just sufficient to cleave apart the kaolin
platelets that make up the booklets without further fracturing the
kaolin platelets. Delamination can involve wet milling, slurry
milling, wet grinding, and the like. Such optional delamination
processes involve the use of a grinding media and water. Kaolin is
combined with the grinding media and water to form a slurry and
transported, such as by pumping, through the delamination
equipment. Typically, the kaolin solids in the slurry during
delamination is from about 5% to about 50% by weight.
[0047] Kaolin may be optionally subjected to one or more heat
treatments. When kaolin is heated, it undergoes a series of
characteristic changes, detectable by various methods including
differential thermal analysis (DTA). Heat treatment may be employed
to form one or more of metakaolin, partially calcined kaolin, and
calcined kaolin, depending on the temperature/duration of the heat
treatment. Heat treatment is performed under one of an inert
atmosphere, an oxidizing atmosphere, and a reducing atmosphere.
[0048] For example, after heating from about 450 to about
650.degree. C. for a sufficient period of time, kaolin undergoes a
strongly endothermic dehydration reaction resulting in the
conversion to material known as metakaolin. The metakaolin state is
conveniently ascertained by acid solubility testing because the
alumina in the clay is virtually completely soluble in strong
mineral acid.
[0049] Calcining destroys the crystallinity of hydrous kaolin and
renders the kaolin substantially amorphous. Calcination occurs
after heating at temperatures in the range from about 700 to about
1200.degree. C. for a sufficient period of time. Commercial
vertical and horizontal rotary calciners can be used to produce
metakaolin, partially calcined kaolin, and/or calcined kaolin.
Operation is controlled to avoid calcining at sufficiently high
temperatures to form unwanted mullite
(3Al.sub.2O.sub.3SiO.sub.2).
[0050] Referring to FIG. 1, a high level diagram of various aspects
of an ultrafine kaolin processing methodology 100 is shown. In act
102, kaolin crude containing at least a super majority of gray
kaolin is optionally degritted, removing relatively large particles
from the gray kaolin crude. After relatively large particles are
removed from the gray kaolin crude, act 104 involves flotation to
reduce the amount of at least one of titania and/or iron oxide in
the degritted kaolin. Act 106 involves optionally ozonating the
kaolin. After ozonation, act 108 involves centrifuging at high
speeds the kaolin and thereby separating the kaolin into two
different grades/streams. The coarse stream produced by act 108 is
subjected to additional processing such as refining and then
employed in paper applications 110. In act 112, the fine stream
from act 108 is subject to refinement, such as flocculation,
bleaching, filtration, and spray drying, to produce an ultrafine
kaolin stream. The ultrafine kaolin is optionally subject to
pulverization 116 to provide the ultrafine kaolin pigments 116.
[0051] Referring to FIG. 2, a system 200 to process gray kaolin
crude into ultrafine kaolin is shown. The system 200 includes one
or more of a degrit system 202 for degritting crude kaolin, a
flotation system 204, an ozonation system 206, and a high-speed
cetrifugation system 208, at least one of which is coupled to a
tester 210 and a processor-controller 212. The degrit system 202
processes gray crude kaolin by removing large grit from the kaolin
crude, the flotation system 204 reduces the titania and or iron
oxide content of the degritted kaolin, the ozonation system 206
oxidizes species within the kaolin process stream, and the
high-speed cetrifugation system 208 separates two distinct kaolin
streams from each other (fine and coarse). The tester 210 can be
any device that measures at least one parameter associated with the
kaolin being processed (such as particle size distribution, surface
area, brightness, whiteness, roughness, % moisture content, %
content of particular chemical such as titania, and the like) or
any parameter associated with any one of the degrit system 202,
flotation system 204, ozonation system 206, and high-speed
cetrifugation system 208 (such as the particle size and/or "g`
force with the high-speed cetrifugation system 208).
[0052] While any one of the degrit system 202, flotation system
204, ozonation system 206, and high-speed cetrifugation system 208
are operating, the tester 210 tests the kaolin being processed. For
example, while the degrit system 202, flotation system 204, or
ozonation system 206 is operating, a sample of kaolin may be
withdrawn and tested to determine a parameter, such as particle
size distribution. The tester 210 sends the data generated by the
testing to the processor-controller 212, which is adapted to
receive such kaolin parameter data from the tester 210.
Alternatively, the tester 210 may measure a parameter of the degrit
system 202, flotation system 204, ozonation system 206, and
cetrifugation system 208, and send data associated with the
parameter to the processor-controller.
[0053] The processor-controller 212 analyzes such data, and based
on the analysis, sends a signal to any of the degrit system 202,
flotation system 204, ozonation system 206, and cetrifugation
system 208 to either continue the process, modify the process, or
terminate the process. To facilitate such analysis, a data store or
memory 214 may be coupled to the processor-controller 212 so that
the processor-controller 212 can compare data sent by the tester
210 to stored data. The processor-controller 212 may send a signal
to the tester 210 to perform a test. Examples of ways in which the
processor-controller 212 can modify a process include increasing or
decreasing the "g" forces in the high-speed cetrifugation system
208; increasing or decreasing the temperature in the flotation
system 204; increasing or decreasing the work/energy required by
any of the degrit system 202, flotation system 204, ozonation
system 206, and/or cetrifugation system 208; continue operating or
terminate any of the degrit system 202, flotation system 204, or
ozonation system 206 to achieve a certain desired particle size
distribution; and the like. Consequently, the system 200 can
provide real time analysis and real time feed back, so that the
processing of kaolin can be modified in real time to suit
immediately existing needs.
[0054] The present invention further relates to paint compositions
containing major amounts of a paint vehicle and minor amounts of
the ultrafine hydrous kaolin described herein. Major amounts
include at least 50% (percent volume of dry paint film) whereas
minor amounts include less than 50% (percent volume of dry paint
film). The paint vehicle may be any one of a latex paint vehicle,
oil based paint vehicle, alkyd paint vehicle, acrylic paint
vehicle, styrene paint vehicle, and/or epoxy paint vehicle. The
paint vehicle contains components suitable for forming a paint
film. Most often, the ultrafine hydrous kaolin described herein
functions as a pigment extender or pigment.
[0055] Paint compositions may be made in any suitable manner. For
example, the components may be combined and mixed. The components
may be combined all at once, or sequentially.
[0056] In one embodiment, the paint compositions of the present
invention contain from 50% to about 99.99% (percent volume of dry
paint film) of a paint vehicle and from about 0.01% to about 49%
(percent volume of dry paint film) of the ultrafine hydrous kaolin.
In another embodiment, the paint compositions of the present
invention contain from about 60% to about 99.9% (percent volume of
dry paint film) of a paint vehicle and from about 0.1% to about 40%
(percent volume of dry paint film) of the ultrafine hydrous kaolin.
In yet another embodiment, the paint compositions of the present
invention contain from about 70% to about 99% (percent volume of
dry paint film) of a paint vehicle and from about 1% to about 30%
(percent volume of dry paint film) of the ultrafine hydrous
kaolin.
[0057] In one embodiment, the ultrafine hydrous kaolin described
herein may be used as a pigment extender with titania as a pigment
in a paint composition. In another embodiment, the paint
compositions of the present invention contain from 50% to about
99.9% (percent volume of dry paint film) of a paint vehicle, from
about 0.1% to about 40% (percent volume of dry paint film) of
titania, and from about 0.1% to about 40% (percent volume of dry
paint film) of the ultrafine hydrous kaolin. In yet another
embodiment, the paint compositions of the present invention contain
from about 60% to about 98% (percent volume of dry paint film) of a
paint vehicle, from about 1% to about 30% (percent volume of dry
paint film) of titania, and from about 1% to about 30% (percent
volume of dry paint film) of the ultrafine hydrous kaolin. In still
yet another embodiment, the ultrafine hydrous kaolin described
herein may be used as a pigment extender with other pigment
extenders such as one or more of clays, carbonates, talc, and
silicas with or without titania as a pigment in a paint
composition.
[0058] One parameter in paint formulation is the pigment volume
concentration (hereinafter PVC). PVC is a control factor in the
design of paint formulations, because paint properties are
generally governed by volume rather than weight effects. The
following equation defines the PVC as a percentage of volume of
dried paint film:
% PVC=100.times.V.sub.pigment/V.sub.total
where V.sub.pigment is the volume of the pigment and other
non-volatiles in the dried paint film and V.sub.total is the
V.sub.pigment plus the volume of the paint vehicle/resin. The
critical pigment volume concentration (hereinafter CPVC) is defined
as that PVC at which air interfaces are generated in the dry paint
film due to the deficiency of binder with respect to pigment. It is
well known that many paint volume properties change drastically at
CPVC. Typically, the relationship between PVC and CPVC is
nonlinear. In many instances, different paints are properly
compared on the basis of equal reduced pigment volume concentration
(hereinafter RPVC). The RPVC is defined by the following
equation:
RPVC=PVC/CPVC
Generally gloss grade paints, either exterior or interior have an
RPVC of less than about 1.
[0059] CPVC is related inversely to the amount of binder that the
pigment particles "absorb." One technique to measure the absorption
potential of a pigment or extender is to determine the amount of
linseed oil needed to form a paste with a given weight of pigment.
This may be referred to as oil absorption. As used herein the term
"oil absorption" refers to the procedure described in ASTM D 281.
Generally speaking, substitution of an equal amount of high oil
absorption extender pigment for one of low oil absorption results
in a reduction of the CPVC of that paint. This is turn restricts
the range of PVC that can be utilized in exterior formulations as
well as the amount of extender pigment, which can be employed.
[0060] Paints with PVC below critical, such as semi- and high-gloss
paints, have no entrapped air in the dry film. The entire solid
surface is wetted by the binder and opacity is obtained solely by
pigment and pigment extender particles. At any given particle
concentration, opacity is improved or optimized by ensuring maximum
surface exposure of the pigment and pigment extender particles to
light. Using the ultrafine hydrous kaolin of the present invention
as a pigment extender with a particle size similar to the pigment
facilitates desirable spacing of the pigment particles, prevents
agglomeration of the pigment particles, and ensures maximum
exposure to light.
[0061] Above the CPVC, paints are considered matte. The degree of
matteness is determined by 85 deg gloss, or what is commonly known
as the sheen. Below the CPVC, paints are glossy and are considered
as either semi-gloss or high gloss. Gloss is typically measured at
60 deg or 20 deg angles.
[0062] The structure (PSD, surface area) the ultrafine hydrous
kaolin of the present invention facilitates gloss retention and
efficient pigment spacing. In one embodiment, the ultrafine hydrous
kaolin of the present invention has a similar size to titania and
fits in desirably between the dispersed titania
particles/agglomerates. In other words, the ultrafine hydrous
kaolin extender works generally as a pigment extender, and
specifically as a TiO.sub.2 pigment spacer, which maximizes
exposure of the pigment surface such as TiO.sub.2 to light,
resulting in higher opacity.
[0063] High gloss and semi gloss grade paints contain a mixture of
prime pigment and extender pigment with titanium dioxide often used
as the prime pigment because of its outstanding optical properties.
The most commonly used extender pigments for latex and alkyd paints
are hydrous kaolin and finer grades of calcium carbonate and talc.
The binder in emulsion paints consists of globules (typically from
about 0.1 to about 1.0 micron diameter) of a film-forming polymer
having a molecular weight from about 10,000 to about 1,000,000. The
latex particle size and composition are varied to effect changes in
such properties as durability, gloss, glass transition temperature
and the like. At present, acrylic and vinyl-acrylic resins account
for the majority of binders used in latex paints.
[0064] Conventionally, it is believed in the paint industry that
increasing the surface area of ultrafine kaolin pigment adversely
affects the gloss performance of the paint at low PVC and below
CPVC. However, the inventors unexpected discovered that a high
surface area ultrafine hydrous kaolin pigment can provide gloss
performance equal to or better than any other hydrous kaolin
pigment available commercially.
[0065] The reasoning behind this discovery is as follows. The
glossing kaolin-based products with 90-91 GEB are typically
produced in the kaolin industry using a tertiary crude such as from
East Georgia and subjecting it a selective flocculation
beneficiation process. One glossing kaolin product, Polygloss.RTM.
90 available from J.M. Huber Corporation, believed to be produced
through such a process, provides the highest gloss among the
commercial pigments available in a number of paint and industrial
coatings applications. The ultrafine kaolin of the present
invention has a finer PSD and a higher surface area than
Polygloss.RTM. 90 and unexpectedly resulted in higher gloss without
compromising the hiding power of the paint film.
[0066] The following examples illustrate the present invention.
Unless otherwise indicated in the following examples and elsewhere
in the specification and claims, all parts and percentages are by
weight, all temperatures are in degrees Centigrade, and pressure is
at or near atmospheric pressure.
EXAMPLE 1
[0067] Table 1 shows the typical characteristics of a gray crude
that facilitates successful execution of the present invention.
Also listed are characteristics of a specific gray kaolin crude
(Example 1) that is used to illustrate the present invention in
Examples 2 and 3.
TABLE-US-00001 TABLE 1 Property Typical values Example 1 GE
Brightness 80-85 82.6 Surface area min 18 (m.sup.2/g) 20
(m.sup.2/g) % TiO.sub.2 1.6-2 1.81 % Fe.sub.2O.sub.3 0.7-1.1 0.9
Particle size, % mass finer than 2 .mu.m 80 82 0.3 .mu.m 35 38
EXAMPLE 2
[0068] The crude from Example 1 is subjected to degritting,
ultraflotation, ozonation, and high-speed centrifuge separation to
result in a fine stream and a coarse stream. Flotation is conducted
so as to reduce the TiO.sub.2 content to less than 0.7%. The
centrifuge is operated under conditions to target 18-22% less than
0.3 .mu.m particle size which typically results in 74-78% less than
2 .mu.m particle size. The coarse stream is further subjected to a
second centrifuge act so as to recover 90% less than 2 .mu.m
particles. The characteristics of the coarse stream subjected to a
second centrifuge act and the fine stream from the first centrifuge
act are shown in Table 2.
TABLE-US-00002 TABLE 2 Property Fines following centrifuge GE
Brightness 91.2 Surface area (m.sup.2/g) 26.2 % TiO.sub.2 0.29 %
Fe.sub.2O.sub.3 0.89 Particle size, % mass finer than 2 .mu.m 100
0.3 .mu.m 71
EXAMPLE 3
[0069] The ultrafines in Table 2 are flocced using sulfuric acid,
bleached, and filtered. The filter cake is dispersed with a
specified blend of soda ash/polyacrylate/phosphate, and spray
dried. The spray dried product is pulverized to a Hegman grind of
6.5. The characteristics of the ultrafine product (UF I) of the
present invention along with a comparison of a commercial
Polygloss.RTM. 90 kaolin pigment are provided below in Table 3.
Also, included is the product ASP.RTM. Superfine hydrous
aluminosilicate produced using a selective flocculation process by
Engelhard Corporation.
TABLE-US-00003 TABLE 3 Properties Polygloss .RTM. 90 UF 1 ASP .RTM.
Superfine Surface Area (m.sup.2/g) 22 26 22.5 TAPPI Brightness, %
90.0 91.7 91.3 Particle Size Distribution Mass % finer than 2 .mu.m
97 99 99 1 .mu.m 96 98 96 0.5 .mu.m 86 92 88 0.3 .mu.m 60 72 66
EXAMPLE 4
[0070] Example 4 demonstrates a solvent neutral base clear alkyd
paint formulation. UF I prepared in accordance with Example 3 is
tested in a gloss paint application. Paint formulations of Examples
4 to 9 are based on 100 gallons volume and an amount of raw
materials in pound per 100 gallons. In the solvent paint there is
no adverse impact on gloss in spite of the finer particle size and
surface area of the UF I compared to Polygloss.RTM. 90.
Solvent Neutral Clear Base Alkyd Paint Formulation
TABLE-US-00004 [0071] Raw Material Amount Gallon VT Alkyd 6693
153.8 20.6 Mineral Spirits 36.4 5.6 Tixogel 8.0 0.1 Ethanol 3.0 0.5
Mix until smooth Lecithin 5 2.0 0.2 Lo-529 2.0 0.2 Anti-Float
Powder 6.0 0.5 Kaolin 40.0 1.9 BYK 370 1.0 0.1 Grind to 7 Hegman,
then add VT Alkyd 6693 380.0 51.0 VM&P 62.0 9.9 Cobalt 12% 1.0
0.1 Zirco 24% 3.0 0.3 Exkin #2 1.0 0.1 Hold for Viscosity VM&P
56.0 8.9 Total 755.2 100.0
Comparative Gloss and Sheen Data of UF I and Polygloss.RTM. 90
TABLE-US-00005 [0072] Properties Polygloss .RTM. 90 UF I 20 degree
Gloss: 73.3 73.5 60 degree Gloss: 91.7 91.7 85 degree Sheen: 96.1
96.5
EXAMPLE 5
[0073] Example 5 demonstrates an Interior semigloss latex paint
formulation. UF I prepared in accordance with Example 3 is tested
in another gloss paint application. In the latex paint there is
significant improvement in gloss with UF I compared to that due to
Polygloss.RTM. 90.
Interior Semigloss Latex Paint Formulation
PVC-22, Low VOC
TABLE-US-00006 [0074] Raw Material Amount Gallon Water 145.0 17.4
KTPP 1.0 0.1 Kathon LX 1.5 0.2 Natrosol Plus 330 1.0 0.1 Tamol 1124
5.0 0.6 Triton CF 10 3.0 0.3 AMP 95 2.0 0.3 Rhodoline 643 1.0 0.1
Mix it for 2 min., then add TiO.sub.2-CR 828 240.0 7.2 Kaolin 20.0
0.9 Attagel 50 5.0 0.3 Grind 6 to 7, then add Water 113.1 13.6 UCAR
300 500.0 56.2 Strodex PK 90 2.0 0.2 Ammonia 2.5 0.3 Polyphobe TR
116 1.0 0.1 Polyphobe TR 117 18.0 2.0 Rhodoline 643 2.0 0.3 Total
1063.1 100.0
Comparative Evaluation b/t UF I and Polygloss.RTM. 90 Semi Gloss
Paint PVC-22
TABLE-US-00007 [0075] Properties UF I Polygloss .RTM. 90 Viscosity
KU @ 77.degree. F. 80 82 pH: 8.3 8.4 C. Ratio 3 mils: 98.7 98.5
Reflectance: 92.3 93.1 Whiteness: 88.2 88.6 Yellowness: 1.6 1.5
Hunter L: 97.5 97.6 Hunter a: -0.9 -1.0 Hunter b: 1.3 1.2 Gloss @
60 deg: 65.1 55.2 Sheen @ 85 deg: 91.8 88.7 Gloss @ 20 deg: 23.1
14.7
EXAMPLE 6
[0076] Example 6 demonstrates a water reducible high gloss alkyd
enamel paint formulation. UF 1 prepared in accordance with Example
3 is tested in a high gloss paint application. In a water reducible
alkyd high gloss enamel paint, there is significant improvement in
the 20 degree gloss value compared to Polygloss.RTM. 90.
Reducible High Gloss Alkyd Enamel Paint Formulation PVC-16
TABLE-US-00008 [0077] Raw Material Amount Gallon Beckosol 10-060
(70%) 72.0 9.0 Mineral Spirits 9.3 1.4 Bentone SD-1 1.5 0.1 Mix
well, then add: LDA 100 Polymeric Dispersant 2.0 0.3 Hex-Cem
Calcium Octoate 10% 3.0 0.4 TiO.sub.2-R-706 110.0 3.3 UF
I/Polygloss .RTM. 90 15.0 0.7 Grind to 7, then add Beckosol 10-060
(70%) 44.5 5.6 Mineral Spirits 18.0 2.8 Mix it well, then add
Beckosol 10-060 (70%) 130.0 16.3 Mineral Spirits 92.4 14.2 Cobalt
Octoate 12% 1.0 0.1 Zirconium Octoate 12% 4.0 0.5 Skine # 2 1.0 0.1
Mix well, then add under agitation: LPR 76, Polysach. Resin 44%
40.0 4.0 Water 344.3 41.3 Mix for 30 min.: Total 888.0 100.0
Comparative Evaluation b/t UF I and Polygloss.RTM. 90 in High Gloss
Alkyd Enamel Paint Formulation PVC-16
TABLE-US-00009 [0078] Properties UF I Polygloss .RTM. 90 Viscosity
KU @ 77.degree. F. 91 92 C. Ratio 3 mils: 92.3 91.9 Reflectance:
87.2 87.0 Whiteness: 77.7 77.3 Yellowness: 4.2 4.3 Hunter L: 95.9
95.9 Hunter a: -1.2 -1.2 Hunter b: 2.7 2.8 Gloss @ 60 deg: 78.8
75.1 Sheen @ 85 deg: 98.3 97.6 Gloss @ 20 deg: 41.5 31.4
EXAMPLE 7
[0079] Example 7 demonstrates a interior/exterior gloss paint
formulation. UF 1 prepared in accordance with Example 3 is tested
in another high gloss paint application. In a styrene acrylic high
gloss waterborne paint, UF 1 exhibited higher 20 and 60 degree
gloss values compared to Polygloss.RTM. 90.
Interior/Exterior Gloss Paint PVC-18.7
TABLE-US-00010 [0080] Raw Material Amount Gallon Water 62.6 7.5
Kathon LX 1.5% 1.6 0.2 Tamol 1124 5.5 0.6 Surfynol 104E 1.0 0.1
Igepal CTA-639W 1.0 0.1 BYK-022 1.0 0.1 Mix for 2 min., then add Ti
Pure-R 706 202.5 6.1 Kaolin 14.5 0.7 Grind 6 to 7, then add
Propylene Glycol 30.28 3.5 Rhoplex HG-700 618.1 70.0 Water 21.45
2.6 Texanol 21.5 2.7 Triton X 405 3.5 0.4 Ammonia 1.0 0.1 Pre mix
following three, then add Water 22 2.6 Acrysol RM 5 22 2.4 BYK-024
2.0 0.3 Total 1031.5 100.0
Comparative Evaluation b/t UF I and Polygloss.RTM. 90 in
Interior/Exterior Gloss Paint PVC-18.7
TABLE-US-00011 [0081] Properties UF I Polygloss .RTM. 90 Viscosity
KU @ 77.degree. F. 94 95 pH 8.4 8.4 C. Ratio 3 mils: 98.2 98.2
Reflectance: 94.5 94.5 Whiteness: 91.0 91.0 Yellowness: 1.1 1.1
Hunter L: 98.0 98.0 Hunter a: -0.8 -0.8 Hunter b: 0.9 0.9 Gloss @
60 deg: 78.5 77.8 Sheen @ 85 deg: 93.4 93.1 Gloss @ 20 deg: 52.3
51.5
EXAMPLE 8
[0082] Example 8 demonstrates a gloss white enamel paint
formulation. UF 1 prepared in accordance with Example 3 is tested
in another high gloss paint application. In another styrene acrylic
enamel paint, 10% TiO.sub.2 is extended with volume amount of UF 1
by keeping the PVC of the paint same. UF 1 unexpectedly exhibited
similar opacity and gloss performance compared to paint having 100%
TiO.sub.2. UF 1 also showed higher gloss in the paint than
Polygloss.RTM. 90.
Gloss White Enamel Paint PVC-17.6
TABLE-US-00012 [0083] (-) 10% TiO.sub.2 by Control 100% TiO.sub.2
kaolin volume Raw Material Amount Gallon Amount Gallon Water 169.2
20.3 169.2 20.3 Kathon LX 1.5% 3.0 0.4 3.0 0.4 KTPP 0.5 0.1 0.5 0.1
Tamol 1124 3.5 0.4 3.5 0.4 Propylene Glycol 26.0 3.0 26.0 3.0
Surfynol 104H 1.0 0.1 1.0 0.1 BYK-022 1.0 0.1 1.0 0.1 Acrysol TT
935 8.0 0.9 8.0 0.9 Ammonia 2.0 0.3 2.0 0.3 Mix it for 2 min., then
add CR 828 225.0 6.8 202.5 6.1 Hydrous Kaolin 0.0 0.0 14.5 0.7
Grind 6 to 7, then add Stordex PK 90 1.0 0.1 1.0 0.1 Ucar 471 516.1
59.6 516.1 59.6 Texanol 20.0 2.5 20.0 2.5 Water 20.7 2.5 20.7 2.5
Synthesizer 160 10.0 1.1 10.0 1.1 Acrysol RM 5 15.0 1.7 15.0 1.7
BYK-024 2.0 0.3 2.0 0.3 Total 1024.0 100.0 1016.0 100.0
Comparative Evaluation b/t UF I and Polygloss.RTM. 90 in Gloss
White Enamel Paint PVC-17.6
TABLE-US-00013 [0084] 100% TiO.sub.2 (-) 10% TiO.sub.2 (-) 10%
TiO.sub.2 Properties Control UF I Polygloss .RTM. 90 Viscosity KU @
77.degree. F. 96 97 95 pH 8.6 8.5 8.5 C. Ratio 3 mils: 98.0 97.8
97.8 Reflectance: 94.4 93.8 93.7 Whiteness: 91.1 90.1 90.1
Yellowness: 0.5 0.7 0.7 Hunter L: 97.9 97.8 97.8 Hunter a: -0.9
-0.9 -0.9 Hunter b: 0.8 1.0 1.0 Gloss @ 60 deg: 75.1 75.3 74.6
Sheen @ 85 deg: 93.4 93.4 92.6 Gloss @ 20 deg: 39.2 38.1 37.2
EXAMPLE 9
[0085] Example 9 demonstrates a two part waterborne epoxy coating
formulation. UF 1 prepared in accordance with Example 3 is tested
in another high gloss paint application. In the high gloss
waterborne epoxy paint formulation, there is improvement in 20
degree gloss value with UF 1, when compared with Polygloss.RTM.
90.
Two Part Waterborne Epoxy Coating PVC-22.7, Usable Pot Life--6
hrs
TABLE-US-00014 [0086] Raw Material Pounds Gallons Part-A EPI-REZ
Resin 3520-WY-55 329.4 36.0 Water 116.3 14.0 Total Part A 445.7
50.0 Part-B EPI-CURE Curing Agent 8536-MY-60 160 19.3 Agitan 731
2.0 0.2 TiO.sub.2-R 900 250 7.5 Kaolin-Polygloss .RTM. 90/UF I 30
1.4 Grind at High speed to 6 to 7, then add EPI-CURE Curing Agent
8536-MY-60 22.5 2.7 Glacial Acetic Acid 2.3 0.3 Water 155.4 18.7
Total Part B 622.2 50.0 Composite Blend Part-A 445.7 50.0 Part-B
621.9 50.0 Total Part A and B 1067.6 100.0
Comparative Evaluation b/t UF I and Polygloss.RTM. 90 in Two Part
Waterborne Epoxy Coating PVC-22.7
TABLE-US-00015 [0087] Properties UF I Polygloss .RTM. 90 Viscosity
KU @ 77.degree. F. 118 119 C. Ratio 3 mils: 97.2 97.0 Reflectance:
90.3 90.2 Whiteness: 81.5 81.7 Yellowness: 3.9 4.1 Hunter L: 97.1
97.1 Hunter a: -1.2 -1.2 Hunter b: 2.5 2.7 Gloss @ 60 deg: 100 100
Sheen @ 85 deg: 97.3 97.0 Gloss @ 20 deg: 98.8 97.7
[0088] While the invention has been explained in relation to
certain embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading the specification. Therefore, it is to be
understood that the invention disclosed herein is intended to cover
such modifications as fall within the scope of the appended
claims.
* * * * *