Note: Descriptions are shown in the official language in which they were submitted.
CA 02391722 2002-06-26
LABELING PAINT AND METHOD FOR THE MANUFACTURE THEREOF
FIELD OF THE INVENTION
The present invention relates-to-a labeling paint composition and method for
its manufacture.
BACKGROUND OF THE INVENTION
Most manufacturers of oriented; strandboaxd (OSB) panels in North America
use a common practice of bundling and packaging multiple panels into units in
preparation for shipment to dis'ixibutors, retailers and lumberyards: Units
are
composed of a stack of about 40 to TUO-panels. Typically the individual panels
are
4 feet wide, and 8 feet or 16 feet long. Individual panel thickness values
range
between 0:225 inch to 1.25 inches. Most units are between 3 to 4 feet in
height and
so the number of panels in a unit is largely determined by the thickness of
the
individual panels.
CA 02391722 2002-06-26
_2_
OSB units are typically subjected to a finishing process-that generally
includes
the following three steps. First, units are transported into a booth where the
four
sides of the unit are sprayed with a liquid edge sealant; which dries to form
a
hydrophobic coating that helps to reduce edge thickness swell if the panels
are
S exposed to rain at construction site. Quite often the liquid edge sealant is
colored to
visually differentiate he product in the marketplace. Then, the sealed unit is
strapped to secure the bundle during shipping and storage. Finally; the sealed
and
strapped unit is labeled (e.g., stenciled) to designate the panel
manufacturer, as well
as the number, ype and size of panels in the unit. Labeling is usually done in
one of
two ways. Units based on the most premium panels are often wrapped in a high
basis weight packaging paper that has a sophisticated, highly decorative label
printed
on the outside.. The packaging paper serves a protective as well as a labeling
function, and in some cases this combination of attributes has been worth the
added
cost. Most OSB units are not wrapped in packaging material, but are instead
labeled
with a relatively simple stencil and paint system.
In the stencil and paint labeling system, a stencil is placed against the side
of a
sealed and strapped OSB unit and paint is sprayed through the stencil onto the
side of
the unit. Generally the stencil is composed of steel or aluminum and is
designed to
create images of letters, numbers, and company logos or icons on the side of
the unit.
Some of these designs can be a bit intricate, especially around the letters
and
numbers. The metal around these intricate areas generally exists as narrow,
strips,
which are delicate and will bend or break with excessive mechanical stress.
Conventional labeling paint for an OSB finishing line, such as High-Hide White
Stencil Paint, which is produced by Associated Chemists lnc. (ACI) [Portland,
OR],
has a color that sharply contrasts with the color of the edge sealant.
Effective
contrasting color selection of the edge sealant and stencil paint provides a
visually
appealing, dramatic appearance to the unit:
Conventional labeling paints are designed to be very lpw in viscosity in order
to
improve the atomization properties of the paint at low spray pressure
settings. Low
spray pressure settings are generally used to minimize the amount of averspray
that
CA 02391722 2002-06-26
-3-
accumulates on the stencil. The low viscosity of conventional labeling paint
makes it
very prone to dripping. Accumulated overspray on the stencil often drips into
some
of the intricate stencil voids where it dries and occludes the opening: To
cope with
this dripping problem, operators on the OSB finishing line are generally
forced to
clean the stencil once every 20 to 25 minutes. In some cases operators apply
heat to
the stencil in an attempt to dry the accumulating paint before it has a chance
to drip.
Heating has marginally improved the dripping problems on some finishing Lines,
but
it increases the complexity of the operation and it represents a burn hazard
to the
operators. Heating can also increase, the strength of the bond between the
paint and
the metal as the paint dries. Unfortmiately, conventional labeling paint forms
a
strong bornl to the metal as it dries and operators must scrape with
considerable force
in order to remove it. Eventually, the harsh scraping action destroys the most
delicate parts of the stencil.
Accordingly, there exists a need for a better labeling paint for an OSB
finishing
Line. The ideal labeling paint has the following attributes.
Re atom eom~liance: The labeling paint is water-based and should not
contain gray highly toxic or hazardous components.
Formulation stability: The labeling paint should not exhibit any phase
separation or sediment formation during storage (the ACI labeling paint
exhibits
gross: sediment formation unless it is frequently agitated).
S,.prayabilitv: The labeling paint is readily atomized in a spray system and
should be resistant to nozzle clogging.
Bleed resistance with edge sealant: Usually, the edge sealant is still wet
when
the labeling paint is applied over it. Because these materials typically have
sharply
contrasting colors; it is important that they do not bleed into each other.
Ability to wet-out edge sealant: The edge sealant generally contains a high
level of waxes and it becomes very hydrophobic as it dries. The labeling paint
must
wet-out the surface of the edge sealant arid' develop adequate bond-strength
to the
edge sealant as it dries.
CA 02391722 2002-06-26
-4-
No dripping: The labeling paint should not drip into the openings (e.g.,
letters or numbers) on the stencil prior to drying.
Film Formation: The labeling paint should form a film as it dries and should
not remain wet and sticky for very long subsequent to application.
Weak bond to metal stencil: The labeling paint must form a very weak bond
to the metal stencil in order to ensure its easy removal from the stencil.
Appearance: The labeling paint hould provide an image; symbol, or icon
that is visually intense and saturated even when the labeling paint is used at
low
application rates.
SUMMARY OF THE INVENTION
The present invention provides a labeling paint and method for its
manufacture.
In one aspect, the invention provides a stable, labeling paint suitable for
use
on an OSB finishing line in conjunction with metal stencils: The labeling
paint is
typically applied to the side of units at spread rates of about 10 to about
300 g/m2.
The labeling paint overspray that accumulates on the stencil is highly
resistant to
dripping and dries to form a soft film that has sufficient bond strength to
the edge
sealant. The labeling paint is easily removed from the metal stencil even
after
excessive drying times. The labeling paint is water-based and can include
opacifying
agents, viscosity enhancing agents, surfactants; a polymeric binding agent
with a
glass transition temperature that. is greater than about 25°C;, and a
debonding agent;
which is active on metal surfaces.
In another aspect of the invention, a method for preparing a labeling paint is
provided. In the method, a stable emulsion is prepared under relatively high
shear
conditions in a first stage. The emulsion includes water and a debonding;
agent that is
active on metal surfaces. In the second stage of the method, the emulsion is
combined with a suspension under relatively low shear conditions to provide
the
paint. The suspension includes: a polymeric binder having a glass transition
temperature greater than about 25°e.
CA 02391722 2004-03-02
4A
In one embodiment, there is provided a method for labeling an oriented
strandboard panel bundle, comprising: (a) placing a stencil against a side of
an
oriented strandboard panel bundle, wherein the bundle comprises a stack of
oriented strandboard panels, and each panel having an exposed edge; (b)
applying a paint composition to the exposed edges of the oriented strandboard
panels by spraying the composition through the stencil; wherein the
composition
comprises a water-based paint composition, comprising: (i) an opacifying
agent;
(ii) a polymeric binding agent; and (iii) a debonding agent active on metal
surfaces; and (c) removing the stencil from the unit.
In a further embodiment, the composition is applied at a spread rate of from
about
to about 300 g/m2.
In a further embodiment, there is provided a method for making a paint
composition, comprising blending an aqueous suspension comprising an
opacifying agent
and a polymeric binding agent having a glass transition temperature greater
than about
25°C with an emulsion comprising a debonding agent active on metal
surfaces, wherein
the debonding agent is present in an amount sufficient to provide a paint
comprising from
about 10 to about 50 percent by weight debonding agent.
In a further embodiment, the emulsion is prepared under high shear conditions.
In a further embodiment, the emulsion further comprises a viscosity enhancing
agent.
In a further embodiment, the emulsion further comprises a surfactant.
In a further embodiment, the suspension further comprises a coalescing agent.
CA 02391722 2004-03-02
4B
In a further embodiment, blending comprises blending under low shear
conditions.
In a further embodiment, the debonding agent comprises a vegetable oil.
In a further embodiment, the debonding agent comprises soybean oil.
In a further embodiment, the polymeric binding agent comprises a latex.
In a further embodiment, the polymeric binding agent comprises a copolymer of
butylacrylate and methyl methacrylate.
In a further embodiment, there is provided a method for making a paint
composition, comprising: (a) preparing a first emulsion comprising water and a
debonding agent active on metal surfaces, wherein the debonding agent is
present in an
amount sufficient to provide a paint comprising from about 10 to about 50
percent by
weight debonding agent; (b) adding a suspension comprising water and a
polymeric
binding agent having a glass transition temperature greater than about
25°C to the first
emulsion to provide a second emulsion; and (c) blending the second emulsion to
provide
the paint composition.
In a further embodiment, preparing the first emulsion comprises blending the
water and debonding agent under high shear conditions.
In a further embodiment, blending the second emulsion comprises blending under
low shear conditions.
In a further embodiment, the debonding agent comprises a vegetable oil.
In a further embodiment, the debonding agent comprises soybean oil.
CA 02391722 2004-03-02
4C
In a further embodiment, the polymeric binding agent comprises a latex.
In a further embodiment, the polymeric binding agent comprises a copolymer of
butylacrylate and methyl methacrylate.
CA 02391722 2002-06-26
DETAILED DESCRIPTION O1~ THE PREFERRED EMBODIMENT
In one aspect, the present invention provides a stable, water-based, labeling
paint suitable for use on an OSB finishing line in conjunction with metal
stencils.
'The paint exhibits no sediment formation or phase separation for about at
least two
S months when stored in a closed container at a emperature of about
20°C. The paint
can be transferred from a reservoir into a. spray gun with conventional pumps
and
hoses. The: paint will not clog nuzzles even after extended stop-and-start run
times.
The paint is typically applied to the side of units of OSB at spread rates of
about 10
to about 300 g/rri ; and at these spread rates it does not bleed excessively
into
previously applied wet edge sealant. The ,paint adequately wets-out the
surface of
previously applied edge sealant: and forms a bond with the edge sealant that
is
sufficient for normal field conditions. The; paint is highl3, resistant to
dripping on the
stencil, and it is easily removed from the stencil even after excessive drying
times of
about 24 hours.
I S In one embodiment; the labeling :paint is water-based and contains
coloring
andlor opacifying agents at a combined level of about 0.S to about 35% by
weight of
the formulation; viscosity enhancing agents at a Ie~el of about O.S to about
10% by
weight of the formulation; surfactants at a level of about O.S to about S% by
weight
of the formulation; a polymeric binding agent, at a level of about 3 to about
30% by
weight of the formulation; and a debonding agent; which is active on metal
surfaces,
at a Ievel of about l0 to about SO% by weight of the formulation. The paint
can also
contain preservatives, optical brighteners,: plasticizers, dispersing aids,
coalescing
agents; and defoaming_agents:
Titanium dioxide is a suitable opacifying agent: Viscosity enhancing agents
2S are exemplified by soluble nonionic polysaccharides; such as
hydraxyethylcellulose
or carboxymethylcellulose. However, suspended particle-type viscosity
enhancing
agents, such as fumed silica, may also be used in this invention. Nonionic and
anionic surfactants can be used in: this formulation. A suitable anionic
surfactant
class is based on the'salts derived from morpholine and long-chain carboxylic
acids,
such as stearic acid, palmitia acid; or rnyristic acid. Suitable polymeric
binding
CA 02391722 2004-03-02
-6-
agents include latices with glass transition temperatures that are greater
than about
25°C. In one embodiment, the polymeric binder is a latex based on a
copolymer of
butylacrylate and methyl methacrylate with a glass transition temperature of
about
32°C and a pH from about 8 to about 9. Effective debonding agents
include
vegetable oils such as soybean oil, corn oil, sunflower oil, castor oil,
rapeseed oil,
linseed oil, sunflower seed oil, or safflower oil. Soybean oil is highly
preferred for
its low odor, low color, availability, and low cost. Silicone oils and mineral
oils can
also be used as debonding agents. A suitable defoaming agent is a non-silicone
TM
defoaming (e.g., Surfynol DF-210 commercially available from Air Product,
Allentown, PA). Suitable preservatives include a mixture of 1-(3-chloroallyl)-
3,5,7-
triaza-1-azoniaadamantane chloride (64%); sodium bicarbonate (33%);
hexamethylenetetramine (2%), and water (1%), commercially available under the
TM
designation Dowicil 75. Suitable dispersing aids include acetylenic diols, for
example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, commercially available under
the
TM
designation Surfynol 104PA. Associative thickeners can also be included in the
paint, including, for example, a polyether polyurethane urea solution in a
mixture of
water and diethylene glycol monobutyl ether, commercially available under the
TM
designation Rheolate 288. Suitable coalescing agents include substituted
glycols, for
example, 2,2,4-trimethyl-1,3-pentanediol mono(2-methylpropanoate),
commercially
TM
available under the designation Texanol.
In another aspect, the present invention provides a method for making a
labeling paint. In one embodiment, the labeling paint is made in two stages.
In a
first stage a stable emulsion is formed under high shear conditions. The
emulsion
includes water and a debonding agent that is active on metal surfaces. In one
embodiment, the emulsion includes water, one or more viscosity enhancing
agents,
one or more surfactants, and one or more debonding agents. In the second
stage, the
emulsion is combined with a suspension under relatively low shear conditions
to
provide the labeling paint. The suspension includes water and a polymeric
binder
having glass transition temperature (Tg) greater than about 25°C. In
one
CA 02391722 2002-06-26
embodiment; the suspension includes water, one or more polymeric binders, and
one
or more opacifying agents.
In one embodiment, -the method of the invention involves an initial step in
which a stable emulsion is produced using mixing equipment that provides a
S relatively high. shearing action. In one embodiment; the emulsion includes
water, a
viscosity enhancing agent, a surFactant and a debonding -additive that is
active on
metal surfaces. Other compounds than can also be incorporated into the
emulsion
include preservatives, defoaming'agents, and stabilizers.
Suitable viscosity enhancing agents include nonionic polysaccharides, such as
l0 hydroxyethylcellulose and carboxymethylcellulose. Nonionic and anionic
suirfactants can also be used fox this invention. In one embodiment; the
emulsion
includes an anionic surfactant that: is based on a long-chain fatty acid and
an amine,
such as morpholine or triethanolamine:
Suitable debonding agents include- vegetable oils; such as soybean oil, and
1 S those noted above. Silicone :oil or mineral oil or mixtures of oils can
also be used as
debanding agents.
Polyols and long chain alcohols; such as s~tearyl alcohol and isostearyl
alcohol, can be used to stabilize the emulsion and increase its viscosity.
These
alcohols may also ultimately 'promote the release of the labeling paint
formulation
20 from the metal stencil.
In one embodiment, the emulsion composition includes water (from about
38:0 to about 93.9%); a viscosity enhancing agent (from about 0:1'to about
2:0%), a
surfactant (from about 1 to about 10%) and a debonding agent active on metal
surfaces {from about 5.0 o about 50.0%). In another embodiment, the emulsion
2S composition includes water (from about 40:0 to about 60.0%), a viscosity
enhancing
agent (from about 0.2 to about 10%), a preservative (from about 0.01 to about
0.3%), a surfactant (from about 3.0 to about S.0%); a debonding agent active
on
rrietal surfaces (from about 30:0 to about 45.0%), and a stabilizing agent
(from about
3.0 to about 6.0%).
CA 02391722 2002-06-26
-y
As noted above, in one embodiment, the labeling paint can be made by a
method having two stages: (l) emulsion formation and (2) emulsion blending.
The
emulsion can be conveniently prepared with multiple vessels. For exa~pie, in
one
vessel a mixture of the debonding : agent and other water insoluble materials
are
combined. It is convenient to add long chain fatty: acids and stabilizing
agents to this
vessel. In many cases this mixture is. stirred and heated to a temperature
sufficient to
melt any solid components in the mixture. Once all of the materials are in a
liquid
state, mild agitation is suf~"xcient to achieve a homogenous mixture. The
molten
mixture can be cooled to room temperature without freezing. In a second vessel
an
aqueous solution is prepared by agitating a mi~cture of water and viscosity
enhancing
agent. It is usually advantageous to add a preservative and an amine to this
aqueous
phase with additional stirring until a single-phase olution has been achieved.
At this
point, the aqueous phase and the debondirrg agent mixture can be combined. The
combination provides a relatively table emulsion with minimal agitation. The
resulting combination can then be subjected to a period of high-shear mixing.
For
instance, it is quite appropriate to subject the mixture to a homogenizes,
which
applies shear to the mixture under high pressure. This results in a finely
dispersed,
stable emulsion with minimal froth. Other 'techniques :can be used to
establish a
finely dispersed emulsion; but the formation of froth should generally be
minimized.
The resulting emulsion has a viscosity that is generally in the range of from
about
500 to about 5000 cps and is stable with respect to phase separation. Thus;
the
emulsion so produced can be shipped to another processing center and/or stored
for
prolonged periods of time.
In a second stags of the method; the emulsion is blended under relatively low
shear mixing conditions with a previously dispersed opacifying agent and a
polymeric binder having a glasstransition temperature greater than about
25°C: In
certain embodiments, additional materials are incorporated into the
formulation.
These include water, defoaming agents, colorants, viscosity enhancing agents,
optical
brighteners, plasticizing agents, coalescing agents, dispersing aids; among
other
additives.
CA 02391722 2002-06-26
-~'
Examples of dispersed or suspended opacifying agents include aqueous
titanium dioxide suspensions or organic pigment suspensions. Typically, these
suspensions axe from about 40 to about 60% solids with an aqueous continuous
phase. In many cases these suspensions will contain small' amounts of a
dispersing
aid.
A suitable polymeric binder is an acrylic latex (e.g.,
butylacrylate/methylmethaerylate copol~rner latex) with a glass transition
temperature that is greater than about 25°C and a pH value that is
between about
8-10.
l7esirable colorants can be based on - aqueous colored organic pigment
dispersions.
Associative thickeners can be used in this part of the formulation to increase
the viscosity.
Coalescing agents, such as ethylene glycol monobutyl ether, can be used to
improve the properties of the final formulation.
In one embodiment, the labeling paint includes the emulsion prepared as
described above (from about 10:D to about 55:0%), opacifying pigment
dispersion
(from about 1.0 to about 50.0%); and a polymeric binder (from about I.0 to
about
50.0%). In another embodiment; the labeling paint includes the emulsion (from
about 30.0 to about 45.0%); .associative-thickener (from about 0.1 to about
1.U%),
opaeifying pigment dispersion (from about 20:0 to about 40:0%); a polymeric
binder
(from about 10:0 to about 20,0%); and a coalescing agent (from about 5 to
about
15%):
Representative labeling paints; their properties, and methods for their
preparation are described in Examples l and 2.
The following examples are provided for the purpose of illustrating, not
limiting, the invention.
CA 02391722 2004-03-02
-10-
EXAMPLES
Example 1
Representative Labeling_Paint Composition,
Preparation, Properties and Application
A representative labeling paint was prepared as follows. A 200-liter primary
mixing vessel was charged with warm water (50°C, 22.50 kg) and a
TM
hydroxyethylcellulose powder, known as Natrosol 250 MBR [Herculese, Inc.;
Hopewell, VA] (250 g). The components were agitated by use of a Cowles
dispenser
(6 inch blade, 1000 rpm) for a period of 30 minutes. A 50% morpholine solution
(aq) (800 g) was added to the primary mixing vessel and the contents were
agitated
by use of the Cowles disperses (6 inch blade, 100 rpm) for an additional five
minutes.
TM
A preservative known as Dowicil 75 [DOW Chemical Inc.; Midland, MI] (40 g) was
added to the primary mixing vessel and the contents were agitated by use of
the
Cowles disperses (6 inch blade, 100 rpm) for an additional five minutes. A
TM
dispersing aid known as Surfynol 104PA [Air Products and Chemical Corp.;
Allentown, PA] (300 g) was added to the primary mixing vessel and the contents
were agitated by use of the Cowles disperses (6 inch blade, 100 rpm) for an
TM
additional five minutes. A titanium dioxide powder, known as Tronox CR-826
[Kerr-McGee Chemical Corp.; Oklahoma City] (17.50 kg) was added to the primary
mixing vessel and the contents were agitated by use of the Cowles disperses (6
inch
blade, I00 rpm) for an additional 30 minutes. A warm oil mixture (65°C,
21.00 kg)
was added to the primary mixing vessel and the contents were agitated by use
of the
Cowles dispenser (6 inch blade, 100 rpm) for an additional 10 minutes. The oil
mixture was comprised of a homogenous blend of soybean oil [Archer Daniels
Midland Co.; Red Wing, MN] (81.67% by weight); a mixture of hydrogenated fatty
TM
acids, known as Pristerene 4910 [Unichema International; Chicago, IL] (13.33%
by
weight); 1-octadecanol [Proctor and Gamble; Cincinnati, OH] (I.67% by weight);
TM
and a polypropylene glycol), average MW = 1050 Da, known as Pluracol P1010
[BASF Corp.; Wyandotte, MI] (3.33% by weight). Warm water (36°C, 13.81
kg)
was added to the primary mixing vessel and the contents were manually agitated
by
CA 02391722 2004-03-02
-11-
use of a paddle in a gentle fashion until the mixture appeared to be
homogenous. An
TM
acrylic latex, a butylacrylate/methylmethacrylate copolymer latex known as CS-
4000
[Rohm and Haas Co.; Philadelphia, PA] (12.40 kg) was added to the primary
mixing
vessel and the contents were manually agitated by use of a paddle in a gentle
fashion
until the mixture appeared to be homogenous. A defoaming agent known as
TM
Surfynol DF-210 [Air Products and Chemical Corp.; Allentown, PA] (400 g) was
added to the primary mixing vessel and the contents were manually agitated by
use
of a paddle in a gentle fashion until the mixture appeared to be homogenous. A
TM
coalescing agent known as Texanol [Eastman Chemical Co.; Kingsport, TN]
( 11.00 kg) was added to the primary mixing vessel and the contents were
manually
agitated by use of a paddle in a gentle fashion until the mixture appeared to
be
homogenous. The formulation was then filtered through a 20 mesh filter and
slowly
cooled to 20-25°C.
The labeling paint prepared as described above had a pH value of 8, a percent
solids value of 44 to 45, and a specific gravity of 1.09 to 1.13. The Hegman
particle
size test value was 7+. The Brookfield viscosity value was 5000 cps at a
temperature
of 24°C(RVF #7, 50 rpm). An aliquot of the formulation was stored
without
agitation in a closed container at a temperature of about 20 to about
25°C for about
two months and no sediment formation or phase separation were observed. The
color of the formulation was bright white and the odor was slight and
pleasant.
The labeling paint described above was shipped to an OSB mill
[Weyerhaeuser Co.; Grayling, MI] and utilized on the finishing line in place
of a
conventional labeling paint [High-Hide White Stencil Paint; Associated
Chemists
Inc.; Portland, OR]. The labeling paint required no agitation in its storage
tank, as
compared to the High-Hide White Stencil Paint, which required constant
agitation.
The labeling paint was easily transferred out of its storage tank to a spray
gun by use
of a 10:1 air motor piston pump. The labeling paint atomized properly as it
exited
the spray gun. Fewer nozzle clogs per day were reported with the labeling
paint than
typically observed with the High-Hide White Stencil Paint. The labeling paint
did
not bleed into the freshly applied green edge sealant on the side of the OSB
units, but
CA 02391722 2002-06-26
12-
it did wet-out the surface of the freshly applied green edge ealant in a
manner that
was sufficient to permitbonding. The edge sealant being need in conjunction
with ,
the labeling paint was known as PF6014-34 [Associated Chemists Inc.; Portland;
OR). The visual contrast between the bright white images formed by the
labeling
paint and the dark green edge sealant as background on the side of the units
was
dramatic and aesthetically pleasing; The labeling paint that accumulated on
the
aluminum stencil did not drip into the lettering or logo voids. The operators
were
able to run the finishing line without cleaning the stencil for four hours at
a time.
The operators reported that they generally needed to stop and clean the
stencil with
the High-Hide Write Stencil Paint once every 20 to 25 minutes. When the
operators
did stop to clean the stencil they reported that the labeling paint was much
easier and
faster to remove than the High-Hide White Stencil Paint. The bond between the
dried labeling paintand the stencil was very weak. The labeling paint tended
to peal
off of the stencil, in large sheets and it left a very thin oily residue on
the surface of
1 S the metai. Overall; the finishing line operators ea~pressed a strong
preference for the
labeling paint.
Example 2
Representative Labeling Paint Composition.
Preparation, Properties, and A,pglieation
A representative labeling paint was prepared as follows.
Emulsion Formation: An emulsion suitable for use in a representative
labeling paint wasprepared as follows. A primary miximg vessel was charged
with
warm water (74°G; 52.85 parts by weight) and a hydroxyethylcellulose
powder;
known as Natrosol 250 A~I$R [Herculese, Tne.; Hopewell, VA) (0:50 parts by
weight): The components were mixed with a high shear rate for a period of 20
minutes. Morpholine (1.00 parts by weight) and triethanolamine (1.00 parts by
weight) were added to the primary mixing vessel and the contents were further
mixed
for an additional 5 minutes. A preservative known as Dowicil 75 [DOW Chemical
Inc.; lVIidIand, MI) (0.15 parts by weight) was added to the primary :mixing
vessel
and the contents were further mixed for an additional 5 minutes. A warm oil
mixture
CA 02391722 2004-03-02
-13-
(55°C, 44.50 parts by weight) was added to the primary mixing vessel
and the
contents were further mixed for an additional 5 minutes. The oil mixture was
comprised of a homogenous blend of soybean oil [Archer Daniels Midland Co.;
Red
Wing, MN] (77.50 parts by weight); a mixture of hydrogenated fatty acids (64%
TM
stearic acid and 28% pahnitic acid), known as Pristerene 4910 [Unichema
International; Chicago, IL] (10.00 parts by weight); isostearyl alcohol, known
as
TM
Prisorine 3515 [Unichema International; Chicago, IL] (2.50 parts by weight);
and a
TM
polypropylene glycol), average MW = 1050 Da, known as Pluracol P1010 [BASF
Corp.; Wyandotte, MI] (10.0 parts by weight). At this point the mixture was a
low
viscosity, opaque, emulsion with a relative coarse level of dispersion. This
warm
mixture was then processed through a two-stage homogenizer with an impingement
pressure of about 3500 psi at a temperature of 55-65°C. The resulting
emulsion was
gradually cooled to a temperature of 20°C.
The emulsion had a viscosity of about 3300 cps [Brookfield, #3 spindle, 20
rpm, 20°C] and a specific gravity of about 0.95. The emulsion did not
exhibit any
phase separation or sedimentation when stored at 20°C for a period of 2
months.
Emulsion Blending. A second primary mixing vessel was charged with the
emulsion prepared as described above (20°C; 39.03 parts by weight) and
water (0.63
parts by weight). The mixture was stirred at a low shear rate for 5 minutes. A
TM
defoaming agent known as Surfynol DF-210 [Air Products and Chemical
Corporation; Allentown, PA] (0.40 parts by weight) was added to the primary
vessel
and the contents were stirred at a low shear rate for an additional 5 minutes.
An
TM
associative thickening agent known as Rheolate 288 [Rheox Incorporated;
Hightstown, NJ] (0.13 parts by weight) was added to the primary vessel and the
contents were stirred at a low shear rate for an additional 5 minutes. A
titanium
dioxide dispersion (2?.20 parts by weight) was added to the vessel and the
contents
were stirred at a low shear rate for an additional 5 minutes. The titanium
dioxide
dispersion was prepared by mixing water (44.70 parts by weight), a dispersing
aid
TM
known as Surfynol 104PA [Air Products and Chemical Corp.; Allentown, PAS (0.40
TM
parts by weight), and titanium dioxide powder, known as Tronox CR-826 [Kerr-
CA 02391722 2004-03-02
-14-
McGee Chemical Corp.; Oklahoma City] (54.90 parts by weight) with high shear
in a
secondary vessel for 30 minutes. An organic white pigment dispersion, a
dispersion
TM
of hollow polymer spheres known as Rhopaque Ultra [Rohm and Haas Co.;
Philadelphia, PA] (6.00 parts by weight), was added to the primary vessel and
the
contents were stirred at a low shear rate for an additional 5 minutes. An
aqueous
latex based on an acrylic polymer with a Tg>25°C,
butylacrylate/methylmethacrylate
TM
copolymer latex, known as CS-4000 [Rohm and Haas Co.; Philadelphia, PA] (16.50
parts by weight), was added to the primary vessel and the contents were
stirred at a
TM
low shear rate for an additional 5 minutes. A coalescing agent known as
Texanol
[Eastman Chemical Co.; Kingsport, TN] (10.00 parts by weight), was added to
the
primary vessel and the contents were stirred at a low shear rate for an
additional 5
minutes.
The resulting formulation had a pH value of 8-9, a specific gravity of 1.0-
1.1.
The Hegman particle size test value was 7+. The formulation had a viscosity of
about 15,000 cps [Brookfield, #6 spindle, 20 rpm, 20°C]. An aliquot of
the
formulation was stored without agitation in a closed container at a
temperature of 20-
25°C for 2 months and no sediment formation or phase separation were
observed.
The color of the formulation was bright white and the odor was slight and
pleasant.
The formulation was readily atomized in a conventional spray paint gun. The
labeling paint did not bleed into freshly applied green edge sealant on the
side of an
OSB unit, but it did wet-out the surface of freshly applied green edge sealant
in a
manner that was sufficient to permit bonding. This formulation was very
resistant to
dripping on a metallic stencil and it dried to form a film that was very
easily pealed
or scrapped off of the metal.
While the preferred embodiment of the invention has been illustrated and
described, it will be appreciated that various changes can be made therein
without
departing from the spirit and scope of the invention.
