U.S. patent application number 16/113307 was filed with the patent office on 2020-02-27 for coated substrates and methods of preparing the same.
The applicant listed for this patent is PPG Industries Ohio, Inc.. Invention is credited to Anthony M. Chasser, Troy James Larimer, Steven Joseph Lemon, Justin Jonathan Martin, Craig Daniel Niederst, John R. Schneider, Brian Edward Woodworth.
Application Number | 20200062969 16/113307 |
Document ID | / |
Family ID | 67876115 |
Filed Date | 2020-02-27 |
United States Patent
Application |
20200062969 |
Kind Code |
A1 |
Chasser; Anthony M. ; et
al. |
February 27, 2020 |
COATED SUBSTRATES AND METHODS OF PREPARING THE SAME
Abstract
The present invention relates to a substrate having (a) a first
material applied to at least a portion of the substrate, and (b) a
coating layer deposited from a powder coating composition including
a film-forming resin, and optionally a crosslinker that is reactive
with the film-forming resin, in direct contact with at least a
portion of the substrate to which the first material has been
applied. The first material is (i) a catalyst that catalyzes cure
of the powder coating composition, (ii) a component reactive with
the film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
Inventors: |
Chasser; Anthony M.;
(Greensburg, PA) ; Schneider; John R.; (Allison
Park, PA) ; Larimer; Troy James; (North Huntingdon,
PA) ; Woodworth; Brian Edward; (Glenshaw, PA)
; Martin; Justin Jonathan; (Irwin, PA) ; Lemon;
Steven Joseph; (Lower Burrell, PA) ; Niederst; Craig
Daniel; (Valencia, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PPG Industries Ohio, Inc. |
Cleveland |
OH |
US |
|
|
Family ID: |
67876115 |
Appl. No.: |
16/113307 |
Filed: |
August 27, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09D 175/06 20130101;
B05D 1/18 20130101; C09D 5/03 20130101; B05D 1/007 20130101; B05D
3/102 20130101; B05D 1/12 20130101; B05D 1/36 20130101; C09D 5/08
20130101; B05D 7/14 20130101; B05D 1/06 20130101 |
International
Class: |
C09D 5/03 20060101
C09D005/03; C09D 5/08 20060101 C09D005/08; C09D 175/06 20060101
C09D175/06 |
Claims
1. A substrate comprising a. a first material applied to at least a
portion of the substrate; and b. a coating layer deposited from a
powder coating composition comprising a film-forming resin, and
optionally a crosslinker that is reactive with the film-forming
resin, in direct contact with at least a portion of the substrate
to which the first material has been applied, wherein the first
material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
2. The substrate of claim 1, wherein the interfacial flow of the
liquidized powder coating composition in contact with at least a
portion of the substrate to which the first material has been
applied is lower than the interfacial flow of the same powder
composition liquidized under the same conditions that is in contact
with an identical substrate with the exception that no first
material has been applied or with a portion of the same substrate
to which the first material has not been applied.
3. The substrate of claim 1, wherein the viscosity of the
liquidized powder coating composition upon and/or after contact
with the first material is higher than the viscosity of the same
powder coating composition liquidized under the same conditions
without contact to the first material.
4. The substrate of claim 1, wherein the first material is
localized at the interface where the powder coating composition
comes into contact with the first material.
5. The substrate of claim 1, wherein the first material migrates
into at least a portion of the powder coating composition.
6. The substrate of claim 1, wherein the first material is the
catalyst that catalyzes cure of the powder coating composition.
7. The substrate of claim 1, wherein the first material is the
component reactive with the film-forming resin and/or the
crosslinker of the powder coating composition.
8. The substrate of claim 7, wherein the first material comprises a
crosslinker, a resin, a reactive diluent, a monomer, or a
combination thereof that is reactive with the film-forming resin
and/or the crosslinker of the powder coating composition.
9. The substrate of claim 1, wherein the first material is the
rheology modifier.
10. The substrate of claim 9, wherein the rheology modifier
comprises silica, chemically modified silica, alumina, chemically
modified alumina, a hydrophobically modified ethylene-oxide
polymer, or any combination thereof.
11. The substrate of claim 1, wherein the first material prior to
application is dispersed or dissolved in a liquid medium.
12. The substrate of claim 11, wherein the liquid medium is an
aqueous liquid medium.
13. The substrate of claim 1, wherein the first material is applied
directly over at least a portion of the substrate.
14. The substrate of claim 1, wherein the first material is
included in a pretreatment composition applied to at least a
portion of the substrate.
15. The substrate of claim 14, wherein there is a greater
concentration of the first material in a surface region of the
pretreatment composition applied to at least a portion of the
substrate than a bulk region of the pretreatment composition
applied to at least a portion of the substrate.
16. The substrate of claim 1, wherein the substrate further
comprises a pretreatment layer and the first material is applied
over at a least portion of the pretreatment layer.
17. The substrate of claim 1, wherein the substrate further
comprises a coating layer and the first material is applied over at
a least portion of the coating layer.
18. The substrate of claim 1, wherein after application to the
substrate, at least a portion of the powder coating composition has
a pill flow rate of greater than 30 mm as measured by the pill flow
test.
19. The substrate of claim 1, wherein the powder coating
composition is physisorbed onto the substrate.
20. The substrate of claim 1, wherein the first material is
physisorbed on the substrate.
21. The substrate of claim 1, wherein the first material is
chemisorbed on the substrate.
22. The substrate of claim 1, further comprising a second coating
composition applied over at least a portion of a coating formed
from the powder coating composition of (b).
23. The substrate of claim 1, wherein the substrate comprises cold
rolled steel, hot rolled steel, steel coated with zinc metal, zinc
compounds, zinc alloys, electrogalvanized steel, hot-dipped
galvanized steel, galvanealed steel, steel plated with zinc alloy,
stainless steel, zinc-aluminum-magnesium alloy coated steel,
aluminum, aluminum alloys, aluminum plated steel, aluminum alloy
plated steel, magnesium, magnesium alloys, nickel, brass, copper,
silver, gold, plastic, or any combination thereof.
24. The substrate of claim 1, wherein the substrate is a fastener,
coiled metal, a vehicle, a package, a heat exchanger, a vent, an
extrusion, roofing, flooring, a wheel, a grate, a belt, a conveyor,
an aircraft, an aircraft component, a vessel, a marine component, a
vehicle, a building, an electrical component, a grain or seed silo,
wire mesh, a screen or grid, HVAC equipment, a frame, a tank, a
cord, a wire, or any combination thereof.
25. The substrate of claim 1, wherein the coating layer formed from
the powder coating composition applied over the substrate to which
the first material has been applied has an R-value of 75% or
greater as compared to an R-value of a coating layer formed from
the powder coating composition applied over a substrate that is
free of the first material, where R-value is measured by the
R-value test.
26. The substrate of claim 1, wherein the dry film thickness of the
coating layer formed from the powder coating composition at the
edge of the substrate is 2 .mu.m or greater.
27. The substrate of claim 1, wherein a ratio of the dry film
thickness of the coating layer formed from the powder coating
composition at the edge and at 10 mm away from the edge into the
center is from 1:3 to 1:15.
28. The substrate of claim 1, wherein the coated substrate has 10%
or less linear edge corrosion after 40 cycles as measured by the
linear edge corrosion test.
29. A method for treating a substrate, sealing at least a portion
of a surface of a substrate, decreasing sag resistance of a coating
on a substrate, improving adhesion of a coating to a substrate,
and/or improving edge coverage of a coating on a substrate
comprising: a. contacting at least a portion of the substrate with
a first material; b. directly contacting at least a portion of the
substrate in contact with the first material with a powder coating
composition comprising a film forming resin and optionally a
crosslinker that is reactive with the film forming resin; and c.
liquidizing the powder coating composition to form a coating layer
of the powder coating composition on the substrate, wherein the
first material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with a film-forming
resin and/or a crosslinker of the powder coating composition,
and/or (iii) a rheology modifier.
30. The method of claim 29, wherein the interfacial flow of the
liquidized powder coating composition in contact with at least a
portion of the substrate to which the first material has been
applied is lower than the interfacial flow of the same powder
composition liquidized under the same conditions that is in contact
with an identical substrate with the exception that no first
material has been applied or with a portion of the same substrate
to which the first material has not been applied.
31. The method of claim 29, wherein the viscosity of the liquidized
powder coating composition upon and/or after contact with the first
material is higher than the viscosity of the same powder coating
composition liquidized under the same conditions without contact to
the first material.
32. The method of claim 29, wherein step (a) comprises dipping the
substrate in a bath that comprises the first material.
33. The method of claim 32, wherein the bath comprises a
pretreatment bath.
34. The method of claim 33, wherein the pretreatment bath is a
cleaner bath, a deoxidizer bath, a cleaner-coater bath, a rinse
conditioner bath, a pretreatment coating bath, a rinsing bath, a
sealing bath, or a deionized water rinsing bath.
35. The method of claim 29, wherein the first material is contained
on and/or in a wipe and step (a) comprises wiping the
substrate.
36. The method of claim 29, wherein the first material is contained
in a liquid formulation and the liquid formulation is sprayed onto
the substrate in step (a).
37. The method of claim 36, wherein the liquid formulation further
comprises a surfactant.
38. The method of claim 29, wherein the first material is deposited
onto the substrate by electrodeposition or vapor deposition in step
(a).
39. The method of claim 29, wherein the first material is bushed or
rolled onto the substrate in step (a).
40. The method of claim 29, wherein the first material is a solid
and is blasted onto the substrate in step (a).
41. The method of claim 29, wherein the substrate is cleaned and
coated with the first material in a single step.
42. The method of claim 29, wherein the substrate is plated with a
metal prior to step (a).
43. The method of claim 29, wherein the substrate comprises an
anodized, cast, or forged metal.
44. The method of claim 29, wherein the substrate is treated prior
to step (a).
45. The method of claim 44, wherein, prior to step (a), the
substrate is alkaline cleaned, deoxidized, mechanically cleaned,
ultrasonically cleaned, plasma cleaned or etched, exposed to
chemical vapor deposition, treated with an adhesion promoter, or
any combination thereof.
46. The method of claim 29, wherein the substrate is pretreated
prior to step (a) with a pretreatment composition.
47. The method of claim 46, wherein the pretreatment composition
comprises a sol-gel, iron phosphate, manganese phosphate, zinc
phosphate, a rare earth metal, permanganate, zirconium, titanium, a
silane, trivalent chrome (TCP), chromate, a silicate, silica,
molybdenum, a lanthanide, metal chelates, metal oxide,
hydrotalcite, phosphonic acid, layered double hydroxide, or any
combination thereof.
48. The method of claim 46, wherein, after pretreatment, the
substrate is rinsed with, sprayed with, or wiped with a solution
that comprises the first material in step (a).
49. The method of claim 46, wherein the pretreatment composition is
dried after application.
50. The method of claim 29, further comprising step (d), contacting
at least a portion of the substrate with a second coating
composition.
51. The method of claim 29, wherein the first material is dried by
air and/or heat after step (a).
52. The method of claim 29, wherein there is no intervening step
between step (a) and step (b).
53. The method of claim 29, wherein first material is applied
directly to the substrate.
54. The method of claim 29, wherein the powder coating composition,
upon cure, has an R-value of 75% or greater as compared to an
R-value of a coating formed from the powder coating composition
applied over a substrate that is free of the first material, where
R-value is measured by the R-value test.
55. The method of claim 29, wherein the dry film thickness of the
coating formed from the powder coating composition at the edge of
the substrate is 2 .mu.m or greater.
56. The method of claim 29, wherein a ratio of the dry film
thickness of the coating formed from the powder coating composition
at the edge and at 10 mm away from the edge into the center is from
1:3 to 1:15.
57. The method of claim 29, wherein the coated substrate has 10% or
less linear edge corrosion after 40 cycles as measured by the
linear edge corrosion test.
58. A method for treating a coil comprising a. contacting at least
a portion of the coil with a first material; b. rolling the coil;
c. unrolling the coil; d. directly contacting at least a portion of
the coil in contact with the first material with a powder coating
composition comprising a film forming resin and optionally a
crosslinker that is reactive with the film forming resin; and e.
liquidizing the powder coating composition to form a coating layer
of the powder coating composition on the coil, wherein the first
material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to substrates and methods for
treating substrates, sealing surfaces of substrates, decreasing sag
resistance, improving adhesion, and improving edge coverage.
BACKGROUND OF THE INVENTION
[0002] Coatings are applied to substrates to provide numerous
properties including protective properties, decorative properties,
and the like. Typically, these coatings are applied across the
entire surface of the substrates including the edges and corners.
However, the compositions that form these coatings often flow over
the edges and corners resulting in low film build around these
areas. As a result, the coatings pull away from the edges and
corners of the substrates, so the properties provided by these
coatings are not obtained or are diminished at the edges and
corners. Thus, it is desirable to provide coated substrates with
improved coating coverage over the edges and corners.
SUMMARY OF THE INVENTION
[0003] The present invention relates to a substrate comprising: (a)
a first material applied to at least a portion of the substrate;
and (b) a coating layer deposited from a powder coating composition
comprising a film-forming resin, and optionally a crosslinker that
is reactive with the film-forming resin, in direct contact with at
least a portion of the substrate to which the first material has
been applied, in which the first material is (i) a catalyst that
catalyzes cure of the powder coating composition, (ii) a component
reactive with the film-forming resin and/or the crosslinker of the
powder coating composition, and/or (iii) a rheology modifier.
[0004] Moreover, the present invention relates a method for
treating a substrate, sealing a surface of a substrate, decreasing
sag resistance, improving adhesion, and/or improving edge coverage
comprising: (a) contacting at least a portion of the substrate with
a first material; (b) directly contacting at least a portion of the
substrate in contact with the first material with a powder coating
composition comprising a film forming resin and optionally a
crosslinker that is reactive with the film forming resin; and (c)
liquidizing the powder coating composition to form a coating layer
of the powder coating composition on the substrate, in which the
first material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
[0005] The present invention also relates to a method of treating a
coil comprising: (a) contacting at least a portion of the coil with
a first material; (b) rolling the coil; (c) unrolling the coil at
later period of time; (d) directly contacting at least a portion of
the coil in contact with the first material with a powder coating
composition comprising a film forming resin and optionally a
crosslinker that is reactive with the film forming resin; and (e)
liquidizing the powder coating composition to form a coating layer
of the powder coating composition on the coil, in which the first
material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
DESCRIPTION OF THE INVENTION
[0006] For purposes of the following detailed description, it is to
be understood that the invention may assume various alternative
variations and step sequences, except where expressly specified to
the contrary. Moreover, other than in any operating examples, or
where otherwise indicated, all numbers expressing, for example,
quantities of ingredients used in the specification and claims are
to be understood as being modified in all instances by the term
"about". At the very least, and not as an attempt to limit the
application of the doctrine of equivalents to the scope of the
claims, each numerical parameter should at least be construed in
light of the number of reported significant digits and by applying
ordinary rounding techniques.
[0007] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contains certain errors necessarily resulting from the
standard variation found in their respective testing
measurements.
[0008] Also, it should be understood that any numerical range
recited herein is intended to include all sub-ranges subsumed
therein. For example, a range of "1 to 10" is intended to include
all sub-ranges between (and including) the recited minimum value of
1 and the recited maximum value of 10, that is, having a minimum
value equal to or greater than 1 and a maximum value of equal to or
less than 10.
[0009] In this application, the use of the singular includes the
plural and plural encompasses singular, unless specifically stated
otherwise. In addition, in this application, the use of "or" means
"and/or" unless specifically stated otherwise, even though "and/or"
may be explicitly used in certain instances. Further, in this
application, the use of "a" or "an" means "at least one" unless
specifically stated otherwise. For example, "a" first material, "a"
coating composition, and the like refer to one or more of any of
these items.
[0010] As previously described, the present invention relates to a
substrate comprising: (a) a first material applied to at least a
portion of the substrate; and (b) a coating layer deposited from a
powder coating composition comprising a film-forming resin, and
optionally a crosslinker reactive with the film-forming resin, that
is in direct contact with at least a portion of the substrate to
which the first material has been applied. That is, the powder
coating composition is applied directly to at least a portion of
the substrate to which the first material is applied before
application of any other intermediate layers. As used herein, a
"powder coating composition" refers to a coating composition
embodied in solid particulate form as opposed to liquid form.
[0011] It is appreciated that the coating layer deposited from the
powder coating composition is formed after liquidizing (i.e.,
melting) the powder coating composition on the substrate to which
the first has been applied. In accordance with the present
invention, the interfacial flow of the liquidized powder coating
composition in contact with at least a portion of the substrate to
which the first material has been applied is lower than the
interfacial flow of the same powder composition liquidized under
the same conditions that is in contact with an identical substrate
with the exception that no first material has been applied or with
a portion of the same substrate to which the first material has not
been applied. The "interfacial flow" refers to the flow of the
liquidized powder coating composition at an interface of the first
material and the liquidized powder coating composition. The
viscosity of the liquidized powder coating composition can also be
higher than the viscosity of the same powder coating composition
liquidized under the same conditions without contact to the first
material.
[0012] The first material of the present invention can be selected
to interact with the desired powder coating composition. The powder
coating composition is typically a curable powder coating
composition that comprises a binder. As used herein, the terms
"curable", "cure", and the like, as used in connection with a
powder coating composition, means that at least a portion of the
components that make up the powder coating composition are
polymerizable and/or crosslinkable including self-crosslinkable
polymers.
[0013] The curable powder coating composition of the present
invention can be cured with heat, increased or reduced pressure,
chemically such as with moisture, or with other means such as
actinic radiation, and combinations thereof. The term "actinic
radiation" refers to electromagnetic radiation that can initiate
chemical reactions. Actinic radiation includes, but is not limited
to, visible light, ultraviolet (UV) light, infrared radiation,
X-ray, and gamma radiation.
[0014] Further, a "binder" refers to a constituent material that
typically holds all coating composition components together upon
cure. The binder comprises one or more film-forming resins that can
be used to form the coating layer. As used herein, a "film-forming
resin" refers to a resin that can form a self-supporting continuous
film on at least a horizontal surface of a substrate upon removal
of any diluents or carriers present in the composition and/or upon
curing. The term "resin" is used interchangeably with "polymer,"
and the term polymer refers to oligomers, homopolymers (e.g.,
prepared from a single monomer species), copolymers (e.g., prepared
from at least two monomer species), terpolymers (e.g., prepared
from at least three monomer species), and graft polymers.
[0015] The powder coating compositions used with the present
invention can include any of a variety of thermosetting powder
coating compositions known in the art. As used herein, the term
"thermosetting" refers to compositions that "set" irreversibly upon
curing or crosslinking, wherein polymer chains of polymeric
components are joined together by covalent bonds. This property is
usually associated with a cross-linking reaction of the composition
constituents often induced, for example, by heat or radiation. Once
cured, a thermosetting resin will not melt upon the application of
heat and is insoluble in solvents.
[0016] The powder coating compositions used with the present
invention can also include thermoplastic powder coating
compositions. As used herein, the term "thermoplastic" refers to
compositions that include polymeric components that are not joined
by covalent bonds and, thereby, can undergo liquid flow upon
heating.
[0017] Non-limiting examples of suitable film-forming resins that
form at least a portion of the binder of the powder coating
composition include (meth)acrylate resins, polyurethanes,
polyesters, polyamides, polyethers, polysiloxanes, epoxy resins,
vinyl resins, copolymers thereof, and combinations thereof. As used
herein, "(meth)acrylate" and like terms refers both to the acrylate
and the corresponding methacrylate. Further, the film-forming
resins can have any of a variety of functional groups including,
but not limited to, carboxylic acid groups, amine groups, epoxide
groups, hydroxyl groups, thiol groups, carbamate groups, amide
groups, urea groups, isocyanate groups (including blocked
isocyanate groups), and combinations thereof.
[0018] Thermosetting coating compositions typically comprise a
crosslinker that may be selected from any of the crosslinkers known
in the art to react with the functionality of one or more
film-forming resins used in the powder coating composition. As used
herein, the term "crosslinker" refers to a molecule comprising two
or more functional groups that are reactive with other functional
groups and that is capable of linking two or more monomers or
polymers through chemical bonds. Alternatively, the film-forming
resins that form the binder of the powder coating composition can
have functional groups that are reactive with themselves; in this
manner, such resins are self-crosslinking.
[0019] Non-limiting examples of crosslinkers include phenolic
resins, amino resins, epoxy resins, triglycidyl isocyanurate,
beta-hydroxy (alkyl) amides, alkylated carbamates, (meth)acrylates,
isocyanates, blocked isocyanates, polyacids, anhydrides,
organometallic acid-functional materials, polyamines, polyamides,
aminoplasts, carbodiimides, oxazolines, and combinations
thereof.
[0020] The powder coating compositions can also be substantially
free, essentially free, or completely free of any of the previously
described film-forming resins and/or crosslinkers. For example, the
powder coating composition can be substantially free, essentially
free, or completely free of a hydroxyl functional film-forming
resin and/or an isocyanate functional crosslinker. The term
"substantially free" as used in this context means the powder
coating composition contains less than 1000 parts per million
(ppm), "essentially free" means less than 100 ppm, and "completely
free" means less than 20 parts per billion (ppb) of a certain
film-forming resin and/or crosslinker such as a hydroxyl functional
film-forming resin and/or an isocyanate functional crosslinker,
based on the total weight of the powder coating composition.
[0021] The powder coating composition can also include other
optional materials. For example, the powder coating compositions
can also comprise a colorant. As used herein, "colorant" refers to
any substance that imparts color and/or other opacity and/or other
visual effect to the composition. The colorant can be added to the
coating in any suitable form, such as discrete particles,
dispersions, solutions, and/or flakes. A single colorant or a
mixture of two or more colorants can be used in the coatings of the
present invention.
[0022] Example colorants include pigments (organic or inorganic),
dyes and tints, such as those used in the paint industry and/or
listed in the Dry Color Manufacturers Association (DCMA), as well
as special effect compositions. A colorant may include, for
example, a finely divided solid powder that is insoluble, but
wettable, under the conditions of use. A colorant can be organic or
inorganic and can be agglomerated or non-agglomerated. Colorants
can be incorporated into the coatings for example by use of a grind
vehicle, such as an acrylic grind vehicle, the use of which will be
familiar to one skilled in the art.
[0023] Example pigments and/or pigment compositions include, but
are not limited to, carbazole dioxazine crude pigment, azo,
monoazo, diazo, naphthol AS, benzimidazolone, isoindolinone,
isoindoline and polycyclic phthalocyanine, quinacridone, perylene,
perinone, diketopyrrolo pyrrole, thioindigo, anthraquinone,
indanthrone, anthrapyrimidine, flavanthrone, pyranthrone,
anthanthrone, dioxazine, triarylcarbonium, quinophthalone pigments,
diketo pyrrolo pyrrole red ("DPPBO red"), titanium dioxide, carbon
black, and mixtures thereof. The terms "pigment".
[0024] Example dyes include, but are not limited to, those that are
solvent and/or aqueous based such as phthalo green or blue, iron
oxide, bismuth vanadate, anthraquinone, and peryleneand
quinacridone.
[0025] Example tints include, but are not limited to, pigments
dispersed in water-based or water miscible carriers such as
AQUA-CHEM 896 commercially available from Degussa, Inc., CHARISMA
COLORANTS and MAXITONER INDUSTRIAL COLORANTS commercially available
from Accurate Dispersions Division of Eastman Chemical, Inc.
[0026] Other non-limiting examples of components that can be used
with the powder coating compositions of the present invention
include plasticizers, abrasion resistant particles, fillers
including, but not limited to, micas, talc, clays, and inorganic
minerals, metal oxides, metal flake, various forms of carbon,
anti-oxidants, hindered amine light stabilizers, UV light absorbers
and stabilizers, surfactants, flow and surface control agents,
thixotropic agents, catalysts, reaction inhibitors,
corrosion-inhibitors, and other customary auxiliaries.
[0027] After being applied over the substrate to which the first
material is applied, the powder coating composition can be
physisorbed onto the substrate. As used herein, "physisorbed",
"physisorption", and like terms refers to a physical adsorption of
a composition or material over the substrate in which the forces
involved are intermolecular forces. Alternatively, the powder
coating composition can be chemisorbed onto the substrate. As used
herein, "chemisorbed", "chemisorption", and like terms refers to a
chemical adsorption of a composition or material over the substrate
in which chemical or ionic bonds are formed.
[0028] As indicated, the first material can be selected to interact
with the powder coating composition. As used herein, the term
"interact" and variants thereof refer to the ability of the first
material to effect or influence any aspect of the powder coating
composition including, for example, its cure, physical/chemical
properties, performance, appearance, and the like. In accordance
with the present invention, the first material is selected from a
catalyst that catalyzes cure of the powder coating composition, a
component that is reactive with at least one component of the
powder coating composition, and/or a rheology modifier that affects
the flow of the liquidized powder coating composition over the
substrate. The first material may comprise any combination of the
first materials selected to interact with the powder coating
composition.
[0029] As used herein, a "catalyst" refers to a material that
increases the rate of reaction of one or more reactive components.
Thus, the first material can comprise a catalyst that increases the
rate of reaction of the film-forming resin(s) and optional
crosslinker(s) that form a binder to thereby catalyze cure of the
powder coating composition. The catalyst used as all or part of the
first material can therefore be selected based on the components
used in the powder coating composition. For example, the binder of
the powder coating composition can comprise a carboxylic acid
functional compound and an epoxy functional compound reactive with
the carboxylic acid functional compound, and the first material can
comprise a catalyst comprising a phosphonium compound, a quaternary
ammonium halide compound, an amine compound, an imidazole compound,
a sulfonium compound, a compound comprising a transition metal
and/or post-transition metal, or any combination thereof that
increases the reaction rate between the acid and epoxy
functionality.
[0030] A "phosphonium compound" refers to a salt comprising a
phosphonium cation. Non-limiting examples of phosphonium compounds
include tetrabutylphosphonium hydroxide and tetrabutylphosphonium
bromide.
[0031] A "quaternary ammonium halide compound" refers a salt
comprising a quaternary ammonium cation and a halogen anion.
Non-limiting examples of quaternary ammonium halide compounds
include dodecyltrimethylammonium chloride, benzyltrimethylammonium
chloride, benzyldimethyloctylammonium chloride, and
hexadecyltrimethylammonium bromide.
[0032] An "amine compound" refers to a compound comprising one or
more primary, secondary, and/or tertiary amines. Non-limiting
examples of amine compounds include 1,4-diazabicyclo[2.2.2]octane,
1,8-diazabicyclo[5.4.0]undec-7-ene, coco alkyl amine, benzyl
diemethyl amine, and 1,1,3,3-tetramethylguanidine.
[0033] An "imidazole compound" refers to a compound comprising a
substituted heterocyclic imidazole structure. Non-limiting examples
of imidazole compounds include 1-methyl imidazole and 2-methyl
imidazole.
[0034] A "sulfonium compound" refers to a salt comprising a
sulfonium cation. A non-limiting example of a sulfonium compound is
trimethylsulfonium iodide.
[0035] A "compound comprising a transition metal" refers to a
compound comprising an element from one of Groups 3-12
(International Union of Pure and Applied Chemistry (IUPAC)) of the
periodic table of the chemical elements, and a "compound comprising
post-transition metal" refers to a compound comprising a
post-transition metal element from one of Groups 13 and 14
(International Union of Pure and Applied Chemistry (IUPAC)) of the
periodic table of the chemical elements. Non-limiting examples of
compounds comprising a transition metal include non diammonium
dihydroxy bis(lactate(2-)-O1,O2) titanate (2-), and zinc octoate.
Non-limiting examples of compounds comprising a post-transition
metal include stannous 2-ethylhexoate and tin(II) oxalate.
[0036] The first material can comprise a component that is reactive
with at least one component of the powder coating composition. For
example, the first material can comprise a component that is
reactive with a film-forming resin(s) and/or crosslinker(s) used in
the binder of the powder coating composition. Non-limiting examples
of such reactive components include a crosslinker, a resin such as
a film-forming resin, a reactive diluent, a monomer, or any
combination thereof.
[0037] It is appreciated that the functionality and types of
crosslinkers, resins, reactive diluents, and monomers used in the
first material are selected to react with the functionality of one
or more components of the powder coating composition. For example,
the powder coating composition can comprise a hydroxyl functional
film-forming resin and the first material can comprise a
crosslinker reactive with the hydroxyl functionality such as, for
example, an oxazoline functional crosslinker, a polycarbodiimide
functional crosslinker, an isocyanate or blocked isocyanate
functional crosslinker, an aminoplast crosslinker, or any
combination thereof. Other non-limiting examples include powder
coating compositions that comprise a carboxylic acid functional
film-forming resin and first materials that comprise an epoxy
crosslinker, a beta-hydroxyalkylamide crosslinker, a
hydroxyalkylurea crosslinker, and/or glycoluril.
[0038] As previously described, the first material can comprise a
rheology modifier. As used herein, a "rheology modifier" refers to
a component that adjusts flow behavior of a composition by
increasing the viscosity of the composition it is in contact with.
Particularly, the rheology modifier used in the first material may
increase the viscosity and adjust the flow of the liquidized powder
coating composition over the substrate. Non-limiting examples of
rheology modifiers include silica, chemically modified silica,
alumina, chemically modified alumina, a hydrophobically modified
ethylene-oxide polymer, or any combination thereof.
[0039] The first material, such as a catalyst, reactive component,
and/or rheology modifier, can be in solid or liquid form. The first
material can also be dispersed or dissolved in an aqueous or
non-aqueous liquid medium. The dispersions and solutions can
comprise additional components including, but not limited to,
surfactants and surfactant solubilizers. It is further appreciated
that the powder coating composition can also include a catalyst,
reactive component such as a crosslinker, and/or rheology modifier
that is different than the catalyst, reactive component, and/or
rheology modifier of the first material.
[0040] As used herein, a "non-aqueous medium" refers to a liquid
medium comprising less than 50 weight % water, based on the total
weight of the liquid medium. Such non-aqueous liquid mediums can
comprise less than 40 weight % water, or less than 30 weight %
water, or less than 20 weight % water, or less than 10 weight %
water, or less than 5% water, based on the total weight of the
liquid medium. The solvents that make up 50 weight % or more of the
liquid medium include organic solvents. Non-limiting examples of
suitable organic solvents include polar organic solvents e.g.
protic organic solvents such as glycols, glycol ether alcohols,
alcohols; and ketones, glycol diethers, esters, and diesters. Other
non-limiting examples of organic solvents include aromatic and
aliphatic hydrocarbons.
[0041] In comparison to a non-aqueous liquid medium, an "aqueous
medium" is a liquid medium that comprises at least 50 weight %
water, such as at least 60 weight % water, or at least 70 weight %
water, or at least 80 weight % water, or at least 90 weight %
water, or at least 95 weight % water, based on the total weight of
the liquid medium.
[0042] When dispersed or dissolved in a liquid medium, the first
material comprises at least 0.05 weight %, at least 0.1 weight %,
or at least 1 weight %, based on the total weight of the dispersion
or solution. The first material can further comprise up to 20
weight %, up to 15 weight %, up to 10 weight %, up to 8 weight %,
up to 5 weight %, or up to 3 weight %, based on the total weight of
the dispersion or solution. The first material can also comprise an
amount within a range, for example, of from 0.05 weight % to 20
weight %, from 0.05 weight % to 10 weight %, from 0.1 weight % to 8
weight %, or from 0.1 weight % to 5 weight %, based on the total
weight of the dispersion or solution.
[0043] The first material can be applied directly to the substrate
without any intermediate layers between the first material and the
substrate. For instance, the first material can be applied directly
to a metal substrate, before or after the substrate is cleaned
and/or treated as further described herein, but before application
of any coating layers. The first material may also be applied
during cleaning such as a component of the cleaner. The first
material can be applied over the entire surface, edges, and corners
of the substrate, or the first material can be applied over
selected portions of the substrate. For example, the first material
can be selectively applied over the edges and corners of the
substrate so that the later applied powder coating composition only
interacts with the first material over the edges and corners of the
substrate. The first material may also form a continuous or
semi-continuous layer over the substrate, or the first material may
applied over certain spots/areas of the substrate such as the edges
and corners of the substrate. As used herein, the area referred to
as the "edge" will vary based on the particular substrate but can
include, e.g., the outer most lateral face of the substrate.
[0044] Once applied, the first material can be physisorbed onto the
substrate in which the first material is physically adsorbed over
the substrate through intermolecular forces. Alternatively, the
first material is chemisorbed onto the substrate in which the first
material is chemically adsorbed over the substrate through valence
forces or chemical bonding.
[0045] The first material can also be incorporated into a
pretreatment composition that is applied over the substrate. As
used herein, a "pretreatment composition" refers to a composition
that reacts with and chemically alters the substrate surface
achieving at least one of the following: 1) formation of a
protective layer; 2) improved substrate topography or reactivity to
enhance coating adhesion; or 3) formation of a protective layer
with improved coating adhesion in comparison to the substrate
without pretreatment. Non-limiting examples of pretreatment
compositions include compositions that comprise iron phosphate,
manganese phosphate, zinc phosphate, a rare earth metal,
permanganate or manganese, molybdate or molybdenum, zirconium,
titanium, halfnium, lanthanides, a silane such as an alkoxysilane,
hydrolyzed silanes and silane oligomers and polymers, metal
chelates, trivalent chrome (TCP), silicate, silica, phosphonic
acids, chromate conversion coating, hydrotalcite, layered double
hydroxide, metal oxides, other metals such as Group IV metals, or
any combination thereof. Non-limiting examples of organic
pretreatments may include chemically modified resins such as
phosphatized epoxies, silanized epoxies and amino functional
resins. The pretreatment may also include anodizing using, such as
for example, sulfuric acid, nitric acid, hydrofluoric acid,
tartaric acid, and other anodizing methods. The pretreatment
composition can be in the form of a sol-gel, a liquid, or a solid.
In some instances, a pretreatment may contain or be sealed using an
oligomeric or polymeric solution or suspension. In yet other
instances, a pretreatment composition may contain small organic
molecules with reactive functionality or those which function as
corrosion inhibitors.
[0046] When the pretreatment composition is applied to the
substrate and cured or dried, a surface region of the pretreatment
layer applied to the substrate can have a greater concentration of
the first material than a bulk region of the layer applied to the
substrate. For example, the surface tension of the first material
can be lower than the surface tension of other components of the
pretreatment composition. As a result, the first material migrates
to the surface of the pretreatment layer (i.e., moves through the
bulk region to the surface region) such that a greater
concentration of the first material can be found in the surface
region, while the remaining amount of the first material is
dispersed throughout the bulk region.
[0047] As used herein, the "surface region" means the region that
is generally parallel to the exposed air-surface of the coated
substrate and which has thickness generally extending
perpendicularly from the surface of the cured coating beneath the
exposed surface. A "bulk region" of the cured composition means the
region which extends beneath the surface region and which is
generally parallel to the surface of the coated substrate.
[0048] The pretreatment composition that includes the first
material can comprise at least 0.05 weight %, at least 0.1 weight
%, or at least 1 weight % of the first material, based on the total
weight of the pretreatment composition. The pretreatment
composition can further comprise up to 20 weight %, up to 15 weight
%, up to 10 weight %, up to 8 weight %, up to 5 weight %, or up to
3 weight % of the first material, based on the total weight of the
pretreatment composition. The pretreatment composition can also
comprise an amount within a range, for example, of from 0.05 weight
% to 20 weight %, from 0.05 weight % to 15 weight %, from 0.05
weight % to 10 weight %, from 0.1 weight % to 8 weight %, or from
0.1 weight % to 5 weight % of the first material, based on the
total weight of the pretreatment composition.
[0049] The first material can also be applied over at least a
portion of a substrate that has already had a previous pretreatment
and/or coating applied. For example, the first material can be
applied to a previously deposited pretreatment layer. Non-limiting
examples of pretreatment layers include layers formed from any of
the previously described pretreatment compositions. The first
material can also be applied over a primer layer or another
previously applied coating layer.
[0050] The first material may be applied in the absence of binder
components that react to form a coating layer when cured such as
through crosslinking. That is, the first material may be applied to
the substrate or a previously applied coating as a non-film forming
composition that does not form a separate coating layer. Thus, the
first material may not be contained in a coating composition that
can be cured to form a coating layer which is separate from the
coating layer formed from the powder coating composition applied
directly over the substrate to which the first material has been
applied. If one or more binder components are present, the dry film
thickness of any potential resulting film may be less than 2.5
microns, less than 2 microns, less than 1.5 microns, less than 1
micron, or less than 0.5 micron. For example, the first material
can be applied such that any other optional components are
substantially free, essentially free, or completely free of binder
components that react to form a separate coating layer from the
powder coating layer when cured. The term "substantially free" as
used in this context means the optional components applied with the
first material contain less than 1000 parts per million (ppm),
"essentially free" means less than 100 ppm, and "completely free"
means less than 20 parts per billion (ppb) of binder components
that react to form a separate coating layer from the powder coating
layer when cured, based on the total weight of all the
components.
[0051] One method for applying the first material to the substrate
comprises dipping the substrate into a solution that contains the
first material. The solution can be, for example, a pretreatment
bath. As used herein, a "pretreatment bath" refers to a liquid bath
containing the first material and that may optionally contain other
components typically found in any type of pretreatment bath.
Non-limiting examples of pretreatment baths that the first material
can be incorporated into include a cleaner bath, a deoxidizer bath,
a cleaner-coater bath, a rinse conditioner bath, a pretreatment
coating bath, a rinsing bath, a sealing bath, or a deionized water
rinsing bath. It will be appreciated that the first material can be
added to any commercially available pretreatment product. It will
also be appreciated that when spray pretreatments are used,
immersion steps may be avoided entirely.
[0052] A "cleaner bath" is a bath comprising materials for removing
grease, dirt, or other extraneous matter from the substrate.
Non-limiting examples of materials for cleaning the substrate
include mild or strong alkaline cleaners.
[0053] A "deoxidizer bath" is a bath comprising materials for
removing an oxide layer found on the surface of the substrate such
as acid-based deoxidizers. Non-limiting examples of acid-based
deoxidizers include phosphoric acid, citric acid, nitric acid,
fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid,
and ammonium bifluoride.
[0054] A "cleaner-coater bath" is a bath comprising materials for
both cleaning and coating the substrate in the same stage. The
cleaner-coater bath can therefore clean the substrate, for example
as with a mild or strong alkaline cleaner, and then coat the
substrate, for example with a pretreatment coating as previously
described, in a single step. A non-limiting example of a
cleaner-coater includes CHEMFOS 51HD, commercially available from
PPG.
[0055] A "rinse conditioner bath" is a bath comprising activating
agents for increasing the number of activation sites on the surface
of the substrate for improved reaction with a pretreatment
composition in order to enhance the protection of the substrate. A
non-limiting example of a rinse conditioner bath is a bath
comprising activating agents that increase the number of sites on
the surface of the substrate where phosphate crystals form upon
application of a phosphate coating.
[0056] A "pretreatment coating bath" refers to a bath comprising a
composition for forming a protective layer over the surface of the
substrate. Non-limiting examples of pretreatment compositions
include any of the pretreatment compositions previously
described.
[0057] A "rinsing bath" is a bath comprising a solution of rinsing
agents to remove any residue after application of a cleaner or
pretreatment layer such as a phosphate containing pretreatment
layer. In some non-limiting examples, a rinsing bath may simply
contain city water or de-ionized water.
[0058] A "sealing bath" is a bath comprising a solution or
dispersion that is capable of affecting a material deposited onto a
substrate in such a way as to enhance its physical and/or chemical
properties. Sealer compositions generally utilize solubilized metal
ions and/or other inorganic materials to enhance the protection
(e.g., corrosion protection) of pretreated substrates. Non-limiting
examples include CHEMSEAL 59 and CHEMSEAL 100, both which are
commercially available from PPG.
[0059] A "deionized water rinsing bath" is a bath that comprises
deionized water and can be utilized in multiple stages of a
pretreatment process such as a final rinsing stage before
drying.
[0060] Other non-limiting examples of application methods that can
be used to apply the first material onto the substrate include:
spraying, such as by incorporating the first material into a liquid
formulation and using spray equipment; wiping where the first
material is contained on and/or in a wipe and manually or
automatically wiped; media blasting where the first material is a
solid and is blasted onto the substrate's surface;
electrostatically applied as a powder; brushing or rolling the
first material over the substrate such as by incorporating the
first material into a formulation (e.g., liquid or gel) that can be
brushed or rolled; vapor deposition; electrodeposition where the
formulation is liquid and is electro-coated; or any combination
thereof. The first material may also be applied in-mold, during
extrusion, during a calendaring, or during other processing of
substrate materials.
[0061] The previously described methods of applying the first
material can also be used in the absence of binder components. For
example, the previously described baths can be substantially free,
essentially free, or completely free of binder components that
react to form a separate coating layer from the powder coating
layer when cured. The term "substantially free" as used in this
context means that the methods such as the baths use or contain
less than 1000 parts per million (ppm), "essentially free" means
less than 100 ppm, and "completely free" means less than 20 parts
per billion (ppb) of binder components that react to form a
separate coating layer from the powder coating layer when cured,
based on the total weight of the components such as the components
that form the baths.
[0062] The first material can be deposited onto the substrate by
one or more of any of the previously described methods. The first
material can also be applied alone or in combination with other
treatments or coating processes. For example, the substrate of the
present invention can be dipped or submerged into one or more of
any of the previously described baths that include the first
material during treatment of the substrate. For instance, the first
material can be incorporated into: a cleaner bath to apply the
first material directly over the surface substrate; a pretreatment
coating bath to apply the first material over the substrate
together with the pretreatment layer; or a final deionized water
rinse to apply the first material over a pretreatment layer. In
another non-limiting example, the substrate is sprayed or wiped
with a solution that comprises the first material after application
of a pretreatment layer or primer layer. In another non-limiting
example, the first material may be present in more than one process
step.
[0063] The substrate can undergo various treatments prior to
application of the first material. For instance, the substrate can
be alkaline cleaned, deoxidized, mechanically cleaned,
ultrasonically cleaned, solvent wiped, roughened, plasma cleaned or
etched, exposed to chemical vapor deposition, treated with an
adhesion promoter, plated, anodized, annealed, cladded, or any
combination thereof prior to application of the first material. The
substrate can be treated using any of the previously described
methods prior to application of the first material such as by
dipping the substrate in a cleaner and/or deoxidizer bath prior to
applying the first material. The substrate can also be plated prior
to applying the first material. As used herein, "plating" refers to
depositing a metal over a surface of the substrate. The substrate
may be also be 3D printed.
[0064] The substrate according to the present invention can be
selected from a wide variety of substrates and combinations
thereof. Non-limiting examples of substrates include vehicles and
automotive substrates, industrial substrates, marine substrates and
components such as ships, vessels, and on-shore and off-shore
installations, storage tanks, packaging substrates, aerospace
components, wood flooring and furniture, fasteners, coiled metals,
heat exchangers, vents, an extrusion, roofing, wheels, grates,
belts, conveyors, grain or seed silos, wire mesh, bolts or nuts, a
screen or grid, HVAC equipment, frames, tanks, cords, wires,
apparel, electronic components, including housings and circuit
boards, glass, sports equipment, including golf balls, stadiums,
buildings, bridges, containers such as a food and beverage
containers, and the like. As used herein, "vehicle" or variations
thereof includes, but is not limited to, civilian, commercial and
military aircraft, and/or land vehicles such as airplanes,
helicopters, cars, motorcycles, and/or trucks. The shape of the
substrate can be in the form of a sheet, plate, bar, rod or any
shape desired.
[0065] The substrates, including any of the substrates previously
described, can be metallic or non-metallic. Metallic substrates
include, but are not limited to, tin, steel, cold rolled steel, hot
rolled steel, steel coated with zinc metal, zinc compounds, zinc
alloys, electrogalvanized steel, hot-dipped galvanized steel,
galvanealed steel, galvalume, steel plated with zinc alloy,
stainless steel, zinc-aluminum-magnesium alloy coated steel,
zinc-aluminum alloys, aluminum, aluminum alloys, aluminum plated
steel, aluminum alloy plated steel, steel coated with a
zinc-aluminum alloy, magnesium, magnesium alloys, nickel, nickel
plating, bronze, tinplate, clad, titanium, brass, copper, silver,
gold, 3-D printed metals, cast or forged metals and alloys, or
combinations thereof.
[0066] Non-metallic substrates include polymeric, plastic,
polyester, polyolefin, polyamide, cellulosic, polystyrene,
polyacrylic, poly(ethylene naphthalate), polypropylene,
polyethylene, nylon, EVOH, polylactic acid, other "green" polymeric
substrates, poly(ethyleneterephthalate) (PET), polycarbonate,
engineering polymers such as poly(etheretherketone) (PEEK),
polycarbonate acrylobutadiene styrene (PC/ABS), polyamide, wood,
veneer, wood composite, particle board, medium density fiberboard,
cement, stone, glass, paper, cardboard, textiles, leather both
synthetic and natural, composite substrates such as fiberglass
composites or carbon fiber composites, 3-D printed polymers and
composites, and the like.
[0067] As indicated, the powder coating composition is directly
applied to at least a portion of the substrate to which the first
material is applied. That is, the powder coating composition is
directly applied to at least a portion of the substrate to which
the first material has been applied, such that the first material
and the powder coating composition are in contact with each other
without any intermediate coating layers in between. The powder
coating composition can be applied to the substrate to which the
first material is applied without any intervening steps such as
drying or heating steps. Alternatively, an additional process
step(s) can be conducted before applying the powder coating
composition including, but not limited to, drying by air and/or
heating the first material. For example, the first material can be
applied in a final deionized water rinse or in a pretreatment
composition and then dried by air or heat before applying the
powder coating composition. The first material can also be applied
to the substrate followed by a rinsing step.
[0068] After application of the powder coating composition, the
first material can be localized at the interface or point of
contact between the first material and the liquidized powder
coating composition. That is, the first material can be in contact
with the liquidized powder coating composition but does not migrate
into the liquidized powder coating composition. Alternatively, at
least a portion of the first material can migrate into at least a
portion of the liquidized powder coating composition. For instance,
the first material can migrate into a portion of the bulk region of
the liquidized powder coating composition.
[0069] The powder coating composition can be applied to the
substrate to which the first material is applied to form a
monocoat. As used herein, a "monocoat" refers to a single coating
layer that is free of additional coating layers. Thus, the powder
coating composition can be applied directly to a substrate and
cured to form a single layer coating, i.e. a monocoat.
[0070] The coated substrate of the present invention may further
comprise one or more additional coating layers, such as a second
coating composition deposited onto at least a portion of the first
powder coating composition, to form a multi-layer coating such as
by applying a topcoat. When a multi-layer coating is formed, the
first powder coating composition can be cured prior to application
of additional coating compositions, or one or more of the
additional coating compositions and the first powder coating
composition can be cured simultaneously. It is appreciated that the
second coating composition and/or additional coating compositions
can be in solid or liquid form.
[0071] The interaction between the powder coating composition and
the first material has been found to effect one or more aspects of
the powder coating composition. For example, the interaction
between the liquidized powder coating composition and the first
material may cause a lower interfacial flow of the liquidized
powder coating composition in contact with at least a portion of
the substrate to which the first material has been applied than the
interfacial flow of the same powder composition liquidized under
the same conditions that is in contact with an identical substrate
with the exception that no first material has been applied or with
a portion of the same substrate to which the first material has not
been applied. As such, when the powder coating composition comes
into contact with the first material that has been applied to the
substrate and is liquidized, the flow of the liquidized powder
coating composition at the contacting interface with the first
material can decrease and is therefore lower as compared to the
same liquidized powder coating composition not in contact with the
first material. The interaction between the liquidized powder
coating composition and the first material may also produce a
higher viscosity in the liquidized powder coating composition than
the viscosity of the same powder coating composition liquidized
under the same conditions that is not in contact with the first
material. The viscosity increase of the liquidized powder coating
composition can be localized and increase at the interface of the
first material, or can extend through all or part of the liquidized
powder coating composition.
[0072] The decrease in interfacial flow and the increase in
viscosity of the liquidized powder coating composition described
herein can be demonstrated through various experiments including
crosslink density and cure times. For instance, the coatings of the
present invention have a higher crosslink density as compared to a
coating deposited from the same powder coating composition applied
over a substrate that is free of the first material. The first
material applied to the substrate therefore decreases the
interfacial flow and increases the viscosity of the liquidized
powder coating composition to allow better crosslinking.
[0073] The crosslink density can be tested with MEK (methyl ethyl
ketone) double rubs in which the index finger of a tester holds a
double thickness of cheesecloth saturated with MEK at a 45 degree
angle to the coated panel surface. Each rub is performed with one
stroke away from the tester and one return stroke toward the
tester. The rubs are performed with moderate pressure at a rate of
about 1 double rub per second and are at least 4'' long. The
cheesecloths are remoistened with MEK every 25 to 50 rubs to ensure
the applicator remains wet throughout the test. The double rubs are
performed until failure of the coating where the coating is removed
from the panel.
[0074] The degree of crosslinking is also demonstrated by other
methods including, but not limited to, solvent soaking and
thermomechanical analysis. In the solvent soaking test, coated
substrates are soaked in a solvent such as acetone, for example for
24 hours. The coating thickness after solvent soaking is then
compared to the coating thickness prior to solvent soaking. The
greater the coating thickness retention after solvent soaking, the
greater the degree of crosslinking. The coating thickness before
and after solvent soaking is measured using 3D digital
Macroscope.
[0075] For thermomechanical analysis, a Q400 thermomechanical
analyzer from TA Instruments Inc. is utilized to investigate the
crosslinked structure by monitoring temperature-driven penetration
behavior. During such testing, a constant ramp of 10.degree. C./min
with a fixed force of 0.1 N can be applied in the temperature range
of 25.degree. C.-150.degree. C. with the force being maintained
until the system cooled down below 25.degree. C. A full penetration
of the entire coating demonstrates a lower crosslinking degree as
compared to partial penetration or two step partial penetration
behavior.
[0076] As indicated, the decrease in interfacial flow and the
increase in viscosity of the liquidized powder coating composition
can also be shown by testing the cure times that the first material
provides as compared to the cure times of the powder coating
composition without the first material. For instance, it was found
that the first material provides a significantly faster gel time
when heated with the components of the powder coating composition
as compared to the gel time of the powder coating composition that
is free of the first material.
[0077] After applying the powder coating composition onto the
substrate to which the first material has been applied, at least a
portion of the powder coating composition can have high pill flow
rate while also exhibiting good edge coverage and coating
appearance as described herein. For instance, at least a portion of
the powder coating composition can have a pill flow rate of greater
than 30 mm while also exhibiting good edge coverage and coating
appearance. The pill flow rate, as reported herein, is measured
according to ASTM D3451-06(2017) and ISO 8130-11, in which a
65.degree. inclined plane frame was used to hold a 20 inch by 12
inch glass plate. The glass plate and frame are heated to
300.degree. F. for 20 minutes before pellets are dropped on the
horizontal plate and allowed to sit one minute before tilting to a
45.degree. angle. The coated plate is then allowed to sit in the
oven for 15 minutes before pulling the glass plate and frame out of
the oven and cooling. Flow is measured from the top to bottom and
reported as millimeters of pill flow. This test is referred to
herein as the "pill flow test".
[0078] As a result of the interaction between the first material
and the powder coating composition, reduced bare metal exposed area
on edges as well as improved coating coverage over the edges and
corners of the substrate has been observed. This may occur, for
example, from a lower interfacial flow at an interface of the first
material and the liquidized powder coating composition, as well as
from a higher viscosity of at least a portion of the liquidized
powder coating composition. For instance, the coated substrates of
the present invention may have greater dry film thicknesses at the
edges as compared to dry film thicknesses at the edges of
substrates coated with the same composition but without the first
material. The coated substrates of the present invention, for
example, may have a dry film thickness at an edge of the substrate
of 2 .mu.m or greater, or 5 .mu.m or greater, or 8 .mu.m or
greater, or 10 .mu.m or greater, or 12 .mu.m or greater. The coated
substrates of the present invention may have a dry film thickness
at an edge of the substrate of up to 25 .mu.m, or up to 20 .mu.m,
or up to 15 .mu.m. The coated substrates of the present invention
may have a dry film thickness at an edge of the substrate within a
range, such as for example, from 2 .mu.m to 25 .mu.m, or from 5
.mu.m to 20 .mu.m, or from 8 .mu.m to 20 .mu.m.
[0079] The coated substrates of the present invention may have a
more consistent or uniform dry film thickness across the surface of
the substrate as compared to substrates coated with the same
composition but without the first material. That is, the dry film
thicknesses at the edges of the coated substrates of the present
invention may be more consistent with the dry film thickness at
other portions of the substrate toward the center of the
substrates, which are historically easier to coat as compared to
the edges. For example, the coated substrate of the present
invention may have a ratio of a dry film thickness at an edge of
the substrate to a dry film thickness 10 mm away from the edge
toward the center of the substrate within a range of from 1:3 to
1:15, or from 1:3 to 1:10, or from 1:4 to 1:12, or from 1:4 to
1:8.
[0080] The coated substrate of the present invention may have
improved corrosion resistance due to improved coating coverage over
the edges and corners of the substrate. Particularly, it was found
that the coated substrates of the present invention may exhibit
less than or equal to 10% linear edge corrosion after 20 or 40
cycles according to SAE J2334. During this corrosion testing, the
coated substrates are cleaned, dried, and held against a template
with 3 mm wide blocks after exposure. The percent (%) linear edge
corrosion of the coated substrate is then determined by counting
the number of marked square blocks on the substrate edges that
exhibit corrosion products, blisters, and adhesion failure. The
percent defects are calculated by taking the total number of
squares with defects divided by the total number of squares from
the evaluated edges. Good edge coverage is demonstrated with an
average value of 3 test substrates below 20% linear edge corrosion,
and excellent edge coverage is demonstrated with an average value
of 5% or less linear edge corrosion. This linear edge corrosion
testing is referred to herein as the "linear edge corrosion
test".
[0081] As indicted, the coated substrates may have good coating
appearance. Particularly, the coated substrates of the present
invention may have an R-value, which can be used to measure coating
appearance, that is close to or the same as an R-value obtained
from a substrate coated with the same composition but without the
first material. For example, the coated substrates of the present
invention have been found to have R-values of 75% or greater, or
80% or greater, or 85% or greater, or 90% or greater, or 95% or
greater, or 100%, of an R-value of a substrate coated with the same
composition but without the first material.
[0082] The R-values of the coated substrates, as reported herein,
are determined by first measuring the longwaves and shortwaves of
the coating substrate using a YK Wavescan Plus available from
BYK-Gardner USA, which measures surface topography via an optical
profile. The wave scan instrument uses a point source (i.e. laser)
to illuminate the surface over a predetermined distance, for
example 10 centimeters, at an angle of incidence of 60.degree.. The
reflected light is measured at the same, but opposite angle. As the
light beam hits a "peak" or "valley" of the surface, a maximum
signal is detected; when the beam hits a "slope" of a peak/valley a
minimum signal is registered. The measured signal frequency is
equal to double spatial frequency of the coating surface
topography. Data are divided into longwave (structure size >0.6
mm) and shortwave (structure size <0.6 mm) signals using a
mathematical filter function. The R-value is then determined within
a scale of 0-10.5, with 10.5 signifying the best appearance. The
calculation for R-Value is as follows: R=10.5-4*log
(a-0.02*|b-20|), where a=20*(10{circumflex over (
)}(Longwave/67)-1) and b=20*(10{circumflex over (
)}(Shortwave/67)-1). If R>10.5, then R=10.5. If |b-20|>40,
then |b-20|=40. This appearance testing is referred to herein as
the "R-value test".
[0083] Substrates coated according to the present invention may
have one or more improved properties and/or may address one or more
issues known in the coating industry. This may include, for
example: improved coating edge coverage; more uniform coverage
across the entire surface of a substrate including the edges and/or
corners; improved sealing over the entire surface of a substrate
including the edges and/or corners; increased sag resistance;
improved adhesion; and/or improved chip resistance such as
resistance during shipping and storing of the coated substrate. As
used herein, "sag" refers to as the undesirable flow of the coating
on vertical or near-vertical surfaces that produce films of unequal
thickness. "Sag resistance" therefore refers to the resistance of
the coating to flow on vertical or near-vertical surfaces.
[0084] The present invention also relates to methods including, for
example, methods for treating a substrate, sealing at least a
portion of a surface of a substrate, decreasing sag resistance,
and/or improving edge coverage comprising: contacting at least a
portion of the substrate with the first material; directly
contacting at least a portion of the substrate in contact with the
first material with a powder coating composition comprising a
film-forming resin, and optionally a crosslinker reactive with the
film-forming resin; and liquidizing the powder coating composition
to form a coating layer of the powder coating composition on the
substrate. The methods of the present invention cause the powder
coating composition to come into contact with the first material.
The resulting interaction between the liquidized powder coating
composition and the first material provided by the method of the
present invention effects one or more aspects of the coating
composition as previously described including, for example, a lower
interfacial flow of the liquidized powder coating composition
and/or a higher viscosity of the liquidized powder coating
composition as compared to the interfacial flow or viscosity of the
same powder composition liquidized under the same conditions that
is in contact with an identical substrate with the exception that
no first material has been applied or with a portion of the same
substrate to which the first material has not been applied.
[0085] The first material and powder coating composition used in
the methods of the present invention include any of the first
materials and powder coating compositions previously described. The
first material can also be applied to the substrate, such as
directly to the substrate without any intermediate layers, using
any of the previously described methods including, for example,
dipping, rinsing, wiping, spraying, vapor or electrodepositing,
brushing, rolling, or blasting.
[0086] The methods of the present invention can also include any of
the additional steps described herein. For example, the methods of
the present invention can also comprise: treating, plating, and/or
applying a pretreatment composition to the substrate before
applying the first material; drying the substrate after applying
the first material by air and/or heat; and/or applying one or more
additional coating compositions.
[0087] The substrates coated according to the methods of the
invention may include any of the previously described substrates
and materials. Different steps can be used to coat certain
substrates and materials for particular end uses and applications.
For example, a coil can be coated by: contacting at least a portion
of the coil with the first material; rolling the coil for storage
and/or shipping; unrolling the coil at later period of time;
directly contacting at least a portion of the coil in contact with
the first material with a powder coating composition comprising a
film-forming resin, and optionally a crosslinker reactive with the
film-forming resin; and liquidizing the powder coating composition
to form a coating layer of the powder coating composition on the
coil. The coil can also be stamped or formed before or after
applying the powder coating composition.
[0088] The following examples are presented to demonstrate the
general principles of the invention. The invention should not be
considered as limited to the specific examples presented. All parts
and percentages in the examples are by weight unless otherwise
indicated.
Examples 1-7
Preparation and Application of Modified Water Rinses
[0089] Deionized water rinses containing a catalyst, crosslinker,
or rheology modifier were first prepared by mixing the components
listed in Table 1 at room temperature.
TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6
Component (grams) (grams) (grams) (grams) (grams) (grams) Hydromax
.RTM. 1.25 1.25 1.25 1.25 1.25 1.25 300.sup.1 TRITON 0.07 0.07 0.07
0.07 0.07 0.07 CF-10.sup.2 Deionized 96.69 92.44 92.44 94.69 96.69
84.4 water Tetrabutyl 2.00 0 0 0 0 0 phosphonium bromide EPOCROS 0
6.25 0 0 0 0 K-2030E.sup.3 CARBODILIT 0 0 6.25 0 0 0 V-02-L2.sup.4
Cardolite 0 0 0 4.00 0 0 NX-8101.sup.5 ACRYSOL 0 0 0 0 2.0 0
RM-12W.sup.6 SNOWTEX 0 0 0 0 0 14.28 ST-O.sup.7 .sup.1A hydrotrope,
nonionic surfactant solubilizer, and electrostatic agent,
commercially available from Alfa Chemicals. .sup.2A nonionic
surfactant, commercially available from DOW.
.sup.3Styrene/acrylic-based oxazoline functionalized reactive
copolymer crosslinker, commercially available from Nippon Shokubai.
.sup.4A polycarbodiimide based crosslinking agent, commercially
available from Nisshinbo Chemical Inc. .sup.5An epoxy curing agent,
commercially available from Cardolite. .sup.6A nonionic urethane
rheology modifier, commercially available from Dow chemical
company. .sup.7Colloidal silica, commercially available from Nissan
Chemical.
[0090] Bare cold rolled steel panels, 4.times.12.times.0.32 inch
available from ACT item #10161 were first cleaned with MEK solvent,
then iron phosphate pretreated with Chemfos.RTM. 51HD (a
cleaner-coater designed to remove soils and deposit a phosphate
coating, commercially available from PPG) solution at 140.degree.
F. for 2 minutes. Each of the panels were next rinsed with
deionized water. The panels were then dipped into the deionized
water rinses containing the components listed in Table 1 for 2
minutes. All panels were dried in an oven for 2 minutes at
110.degree. C. and allowed to cool to room temperature.
[0091] In addition, a control panel (Comparative Example 7) was
also prepared by dipping the panel into a Chemfos.RTM. 51HD
solution at 140.degree. F. for 2 minutes, and then rinsing with
deionized water. The panel was dried in an oven for 2 minutes at
110.degree. C. and allowed to cool to room temperature.
Example 8
Preparation of coated substrates
[0092] The substrates of each of Examples 1-7 were
electrostatically sprayed with a powder coating composition
comprising a carboxylic acid functional polyester, a triglycidyl
isocyanurate cross-linker, and standard additives and fillers using
a Nordson LAD series electrostatic spray system at 35 kV with 9 psi
flow and 10 psi fluidization settings with a slot tip. The powder
coating compositions were sprayed at 40-50% relative humidity. The
powder coating compositions were applied on the front and back of
the substrates at a dry film thickness of 50 microns to 100
microns. The powder coating were heated in an electric oven
(Despatch LAD series electric oven) for 20 minutes at 375.degree.
F. to cure and form the coatings.
Example 9
Evaluation of coated substrates
[0093] The coated substrates of Example 8 were tested for coating
appearance. The coating appearance of each coating was tested by
the R-value test previously described herein. The resulting
R-values of the coatings formed over the substrates of Examples 1-7
are listed in Table 2.
TABLE-US-00002 TABLE 2 Substrate coated R-value Example 1 4.8
Example 2 4.6 Example 3 5.2 Example 4 5.4 Example 5 N/A Example 6
N/A Comparative Example 7 5.0
[0094] As shown in Table 2, the R-values of the coated substrates
treated with the deionized water rinses containing catalyst,
crosslinker, or rheology modifier of Examples 1-4 exhibited similar
R-values as compared to the coated substrate of Comparative Example
7 that was not treated with the deionized water rinses containing
catalyst, crosslinker, or rheology modifier.
Examples 10 and 11
Preparation and Application of a Solution Containing Catalyst
[0095] A deionized water rinse containing a catalyst was first
prepared from the components listed in Table 3.
TABLE-US-00003 TABLE 3 Components Example 10 (grams) Deionized
water 96.69 Tetrabutyl phosphonium bromide 2 TRITON CF-10.sup.1
0.07 Hydromax .RTM. 300.sup.2 1.25
[0096] Bare cold rolled steel panels, 4.times.12.times.0.32 inch
available from ACT item #10161 were dipped into the deionized water
rinses containing the components listed in Table 3 for 2 minutes.
The panels were dried in an oven for 3 minutes at 110.degree. C.
and allowed to cool to room temperature. In addition, an untreated
panel was selected as a control (Comparative Example 11).
Example 12
Preparation of Coated Substrates
[0097] Three substrates of each of Examples 10 and 11 were
electrostatically sprayed with a powder coating composition
comprising a carboxylic acid functional polyester, a triglycidyl
isocyanurate cross-linker, and standard additives and fillers using
a Nordson LAD series electrostatic spray system at 35 kV with 9 psi
flow and 10 psi fluidization settings with a slot tip. The powder
coating compositions were sprayed at 40-50% relative humidity. The
powder coating compositions were also applied on the front and back
of the substrates at a dry film thickness of 50 microns to 100
microns. The powder coatings were heated in an electric oven
(Despatch LAD series electric oven) for 20 minutes at 375.degree.
F. to cure and form the coatings.
Example 13
Evaluation of Coated Substrates
[0098] The coated substrates of Example 12 were tested for linear
edge corrosion. The linear edge corrosion of each coated substrate
was tested by the linear edge corrosion test previously described
herein. The resulting linear edge corrosion percentages of the
coated substrates are listed in Table 4.
TABLE-US-00004 TABLE 4 Substrate coated % Linear Corrosion Example
10 3.5 Comparative Example 11 95
[0099] As shown in Table 4, the coated substrates treated with the
deionized water rinse containing catalyst of Example 10 exhibited
low linear edge corrosion percentages as compared to the coated
substrates of Comparative Example 11 that were not treated with the
deionized water rinse containing catalyst.
Example 14
Application of a Solution Containing Catalyst Using Different
Application Techniques
[0100] The solution containing the catalyst described in Example 10
and shown in Table 3 was applied to bare cold rolled steel panels,
4.times.12.times.0.32 inch available from ACT item #10161, that
were shear cut along the sides and bottom of the panel .about. 1/16
of an inch or less off to provide sharp edges for testing. The
sheared test panels were first cleaned with MEK solvent, then iron
phosphate pretreated with Chemfos 51HD.RTM. solution at 140.degree.
F. for 2 minutes, and finally rinsed with deionized water. Each
panel was then treated with the solution containing the catalyst
using different application methods on the bottom half of the
panels.
[0101] The first method of application comprised dipping the panel
half way into the treatment solution for 20 seconds. The second
method of application comprised applying the treatment solution on
the edges by wetting a Q-tip with the treatment solution and
applying the solution evenly to the edges on the bottom half of the
test panel. The third method of application comprised filling a
spray bottle with the treatment and spraying the treatment solution
onto the bottom half of the test panel. After the treatment
solution was applied, the panels were dried for 2 minutes at
110.degree. C. and allowed to cool to room temperature.
Example 15
Preparation and Evaluation of Coated Substrates
[0102] The substrates of Example 14 were electrostatically sprayed
with a powder coating composition comprising a carboxylic acid
functional polyester, a triglycidyl isocyanurate cross-linker, and
standard additives and fillers using a Nordson LAD series
electrostatic spray system at 35 kV with 9 psi flow and 10 psi
fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coating were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0103] The coated substrates were tested by the R-value test
previously described herein. The average edge coverage of each
coated substrate was also tested.
[0104] The edge coverage was tested using FE-SEM Analysis. For the
edge coverage test, small square sections were cut from an area of
each panel with no surface treatment (top right, top left), and an
area with surface treatment (bottom right, and bottom left edges)
with a panel cutter and mounted in epoxy overnight. After curing,
the mounts were ground, polished, and placed on aluminum stubs with
carbon tape. Samples were then coated with Au/Pd for 20 seconds and
analyzed in a Quanta 250 FEG SEM under high vacuum. The
accelerating voltage was set to 20.00 kV and the spot size was 3.0.
The samples were viewed in both secondary and back-scatter mode
depending on which image allowed the best contrast. Three dry film
thickness measurements were collected from around the front and
back panel edges and averaged to provide average edge coverage
measurements for each area. The measurements were taken at the
thinnest part of the coating at the edge of the substrate.
[0105] The test results of the R-value and average edge coverage
are listed in Table 5.
TABLE-US-00005 TABLE 5 R-value R-value .mu.m Average .mu.m Average
Application untreated treated edge coverage edge coverage method
top bottom untreated top treated bottom Immersion 3.8 3.1 2.8 10.2
Wipe-Q-tip edges 3.7 3.7 3.5 9.1 Spray applied 3.8 3.0 2.9 6.9
[0106] As shown in Table 5, the portions of the coated substrates
treated with the different methods all exhibited good R-values and
improved edge coverage as compared to the untreated portions of the
coated substrates.
Example 16
Application of a Solution Containing Catalyst on Differently
Treated Substrates
[0107] The solution containing the catalyst described in Example 10
and shown in Table 3 was applied to bare cold rolled steel panels,
4.times.12.times.0.32 inch available from ACT item #10161, that
were shear cut along the sides and bottom of the panel .about. 1/16
of an inch or less off to provide sharp edges for testing. Prior to
applying the treatment solution, the sheared test panels were first
cleaned with MEK solvent followed by one of three different surface
treatments.
[0108] The first surface treatment was an iron phosphate treatment
that was applied through Chemfos.RTM. 51HD at 140.degree. F. for 2
minutes, and then rinsed with deionized water.
[0109] For the second treatment, Zircobond pretreatment panels were
first cleaned with a commercially available cleaner from PPG
Industries, ChemKleen SP1, in a stainless steel spray cabinet using
V-jet nozzles at 10 to 15 psi for two minutes at 49.degree. C.,
followed by an immersion rinse in DI water for 15 seconds and spray
rinsed with DI water for another 15 seconds. Following the cleaning
and rinsing, the panels were immersed into a Zircobond 4200 bath
(thin film pretreatment commercially available from PPG Industries,
Inc.) A five-gallon solution of Zircobond 4200 DM/DR (a
zirconium-containing pretreatment composition commercially
available from PPG Industries) was prepared according to the
manufacturer's instructions. Temperature of the bath was 80.degree.
F. and the panels were run through the bath for 2 minutes with low
agitation. Panels were then spray rinsed for 15-20 seconds with DI
water and warm air dried using a Hi-Velocity handheld blow-dryer
made by Oster.RTM. (model number 078302-300-000) at a temperature
of about 50-55.degree. C. until the panels were dry (about 1-5
minutes).
[0110] The third surface treatment involved cleaning the panel
surface using PPG Chemi Kleen 2010Lp with a surfactant package at
135.degree. F. The panels were dipped into the cleaner solution for
2 minutes, then DI water rinsed.
[0111] The bottom half of the of each of the panels was then dipped
into the treatment solution for 10 seconds then allowed to dry in
an oven at 110.degree. C. for two minutes.
Example 17
Preparation and Evaluation of Coated Substrates
[0112] The substrates of Example 16 were electrostatically sprayed
with a powder coating composition comprising a carboxylic acid
functional polyester, a triglycidyl isocyanurate cross-linker, and
standard additives and fillers using a Nordson LAD series
electrostatic spray system at 35 kV with 9 psi flow and 10 psi
fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coating were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0113] The coated substrates were tested by the R-value and average
edge coverage tests previously described herein. The test results
of the R-value and average edge coverage are listed in Table 6.
TABLE-US-00006 TABLE 6 R-value R-value .mu.m Average .mu.m Average
Panel surface untreated treated edge coverage edge coverage
pretreatment top bottom untreated top treated bottom Iron Phosphate
3.8 3.1 2.8 10.2 Clean only 3.2 2.6 1.8 7.8 Zirconium 3.8 3.0 7.8
19.7
[0114] As shown in Table 6, the portions of each of the coated
substrates treated with catalyst all exhibited good R-values and
improved edge coverage as compared to the untreated portions of the
coated substrates.
Example 18
Application of a Solution Containing Catalyst on Different
Substrates
[0115] The solution containing the catalyst described in Example 10
and shown in Table 3 was applied to bare cold rolled steel panels,
4.times.12.times.0.32 inch available from ACT item #10161, and
aluminum 3003 H14, mill finish 0.025''.times.4''.times.12''
available from Q-panel item A412, that were each shear cut along
the sides and bottom of the panel .about. 1/16 of an inch or less
off to provide sharp edges for testing.
[0116] The cold rolled steel panel surface was prepared with a
simple cleaning of the surface using PPG Chemi Kleen 2010Lp with a
surfactant package at 135.degree. F. The panels were dipped into
the cleaner solution for 2 minutes, then DI water rinsed.
[0117] The aluminum panel surface was cleaned with commercially
available ULTRAX 14 AWS at a concentration of 3.5% at 100.degree.
F. for 3.5 minutes in a spray tank. After cleaning the bottom half,
each of the panels was dipped into the treatment solution for 10
seconds then allowed to dry in an oven at 110.degree. C. for two
minutes.
Example 19
Preparation and Evaluation of Coated Substrates
[0118] The substrates of Example 18 were electrostatically sprayed
with a powder coating composition comprising a carboxylic acid
functional polyester, a triglycidyl isocyanurate cross-linker, and
standard additives and fillers using a Nordson LAD series
electrostatic spray system at 35 kV with 9 psi flow and 10 psi
fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0119] The coated substrates were tested by the R-value and average
edge coverage tests previously described herein. The test results
of the R-value and average edge coverage are listed in Table 7.
TABLE-US-00007 TABLE 7 R-value R-value .mu.m Average .mu.m Average
untreated treated edge coverage edge coverage Substrate top bottom
untreated top treated bottom cold rolled steel 3.2 2.6 1.8 7.8
Aluminum 3.8 3.0 5.1 9.6
[0120] As shown in Table 7, the portions of the coated substrates
treated with catalyst exhibited good R-values and improved edge
coverage as compared to the untreated portions of the coated
substrates.
Example 20
Preparation and Application of Different Surface Treatments
[0121] Surface treatments containing different treatment materials
were prepared by mixing the components listed in Table 8 at room
temperature. The solutions containing the carbodiimide, rheology
modifier and epoxy cross-linker were held under magnetic stir bar
mixing until use.
TABLE-US-00008 TABLE 8 Catalyst Rheology Example Crosslinker
Crosslinker Modifier percent Example Example Example total percent
percent total percent total Components weight total weight weight
weight Hydromax .RTM. 1.25 1.25 1.25 1.25 300.sup.1 TRITON
CF-10.sup.2 0.07 0.07 0.07 0.07 Deionized 96.69 92.44 94.69 96.69
water Tetrabutyl 2.00 0 0 0 phosphonium bromide Carbodilite
EO5.sup.8 0 6.25 0 0 Cardolite 0 0 4.00 0 NX-8101.sup.9 ACRYSOL 0 0
0 2.0 RM-12W.sup.6 .sup.8A polycarbodiimide crosslinking agent,
commercially available from Nisshinbo Chemical Inc. .sup.9An epoxy
curing agent, commercially available from Cardolite.
[0122] The treatment solutions were applied to bare cold rolled
steel panels, 4.times.12.times.0.32 inch available from ACT item
#10161, that were shear cut along the sides and bottom of the panel
.about. 1/16 of an inch or less off to provide sharp edges for
testing. The sheared test panels were first cleaned with MEK
solvent, then iron phosphate pretreated with Chemfos.RTM. 51HD
solution at 140.degree. F. for 2 minutes, and finally rinsed with
deionized water. Each panel was then treated with one of the
treatment solutions by dipping the panels half way into the
respective treatment solution for 10 seconds. The panels were then
dried for 2 minutes at 110.degree. C. and allowed to cool to room
temperature.
Example 21
Preparation and Evaluation of Coated Substrates
[0123] The substrates of Example 20 were electrostatically sprayed
with a powder coating composition comprising a carboxylic acid
functional polyester, a triglycidyl isocyanurate cross-linker, and
standard additives and fillers using a Nordson LAD series
electrostatic spray system at 35 kV with 9 psi flow and 10 psi
fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0124] The coated substrates were tested by the R-value and average
edge coverage tests previously described herein. The test results
of the R-value and average edge coverage are listed in Table 9.
TABLE-US-00009 TABLE 9 R-value R-value .mu.m Average .mu.m Average
Panel surface untreated treated edge coverage edge coverage
pretreatment top bottom untreated top treated bottom Tetrabutyl 3.2
2.6 1.8 7.8 phosphonium bromide Carbodilit EO5.sup.8 3.4 3.3 3.4
7.8 Cardolite NX- 3.7 3.2 2.5 6.9 8101.sup.9 ACRYSOL RM- 4.1 3.5
1.7 7.4 12W.sup.6
[0125] As shown in Table 9, the portions of the coated substrates
treated with catalyst, crosslinker, or rheology modifier all
exhibited good R-values and improved edge coverage as compared to
the untreated portions of the coated substrates.
Example 22
Preparation and Application of Treatments Solutions at Different
Stages
[0126] Treatment solutions were prepared by mixing the components
listed in Table 10 at room temperature under magnetic stir bar
mixing until use, except for Chemfos.RTM. 51HD which was heated to
140.degree. F. at the time of use.
TABLE-US-00010 TABLE 10 Pretreatment Final Rinse Example Sealer
Example Example percent percent total percent Components total
weight weight total weight Hydromax .RTM. 300.sup.1 1.25 0 0 TRITON
CF-10.sup.2 0.07 0 0 Deionized water 96.69 0 0 Tetrabutyl 2.00 2.0
2.0 phosphonium bromide Chemfos .RTM. 51HD.sup.10 0 98 0 Chemseal
100.sup.11 0 0 98 .sup.10A chrome-free final rinse, commercially
available from PPG. .sup.11A chrome-free organic passivation rinse,
commercially available from PPG.
[0127] The treatment solutions were applied to bare cold rolled
steel panels, 4.times.12.times.0.32 inch available from ACT item
#10161, that were shear cut along the sides and bottom of the panel
.about. 1/16 of an inch or less off to provide sharp edges for
testing.
[0128] A first set of the sheared test panels were cleaned with MEK
solvent, then iron phosphate pretreated with Chemfos 51HD.RTM. at
140.degree. F. for 2 minutes, and then finally rinsed with a DI
water rinse containing catalyst, as listed in Table 10 as the final
rinse Example. Each panel was dried for 2 minutes at 110.degree. C.
and allowed to cool to room temperature.
[0129] A second set of the sheared test panels were cleaned with
MEK solvent, and then iron phosphate pretreated with Chemfos
51HD.RTM. containing catalyst and other components at 140.degree.
F. for 2 minutes by dipping the panels into the solution, as listed
in Table 10 as the pretreatment Example. Each panel was dried for 2
minutes at 110.degree. C. and allowed to cool to room
temperature.
[0130] A third set of the sheared test panels were cleaned with MEK
solvent, iron phosphate pretreated with Chemfos.RTM. 51HD at
140.degree. F. for 2 minutes, rinsed with deionized water, and
finally sealed with Chemseal 100 containing catalyst, as listed in
Table 10 as the sealer Example. Each panel was dried for 2 minutes
at 110.degree. C. and allowed to cool to room temperature.
Example 23
Preparation and Evaluation of Coated Substrates
[0131] The substrates of Example 22 were electrostatically sprayed
with a powder coating composition comprising a carboxylic acid
functional polyester, a triglycidyl isocyanurate cross-linker, and
standard additives and fillers using a Nordson LAD series
electrostatic spray system at 35 kV with 9 psi flow and 10 psi
fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0132] The coated substrates were tested by the R-value and average
edge coverage tests previously described herein. The test results
of the R-value and average edge coverage are listed in Table
11.
TABLE-US-00011 TABLE 11 R-value R-value .mu.m Average .mu.m Average
untreated treated edge coverage edge coverage Stage of treatment
top bottom untreated top treated bottom Final Rinse 3.8 3.1 2.8
10.2 Sealer 3.7 3.9 1.9 7.7 Pretreatment 3.8 2.9 4.51 10.5
[0133] As shown in Table 11, the portions of the coated substrates
treated with catalyst all exhibited good R-values and improved edge
coverage as compared to the untreated portions of the coated
substrates.
Example 24
Preparation and Application of Treatment Solutions
[0134] Treatment solutions were prepared by mixing the components
listed in Table 12 at room temperature.
TABLE-US-00012 TABLE 12 Catalyst Example Crosslinker Example
Components percent total weight percent total weight Hydromax .RTM.
300.sup.1 1.25 1.25 TRITON CF-10.sup.2 0.07 0.07 Deionized water
96.69 94.69 Tetrabutyl 2.00 0 phosphonium bromide Cardolite
NX-8101.sup.9 0 4.00
[0135] The treatment solutions were applied to bare cold rolled
steel panels, 4.times.12.times.0.32 inch available from ACT item
#10161, that were shear cut along the sides and bottom of the panel
.about. 1/16 of an inch or less off to provide sharp edges for
testing. The sheared test panels were first cleaned with MEK
solvent, then rinsed with deionized water. The panels were then
subjected to a final rinse by dipping the bottom half of the panels
for 20 seconds in the solutions and put into an oven to dry for 2
minutes at 110.degree. C.
Example 25
Preparation and Evaluation of Coated Substrates
[0136] The substrates of Example 24 were electrostatically sprayed
with a powder coating composition comprising either: (1) a
carboxylic acid functional polyester, triglycidyl isocyanurate
cross-linker, and standard additives and fillers (referred to as
"acid epoxy"); (2) an epoxy functional polymer, phenol functional
crosslinker, and standard additives and fillers (referred to as
"epoxy phenol"); or (3) a carboxylic acid functional polyester,
hydroxylalkylamide crosslinker, and standard additives and fillers
(referred to as "acid hydroxyalkylamide").
[0137] The powders compositions were sprayed with a Nordson LAD
series electrostatic spray system at 35 kV with 9 psi flow and 10
psi fluidization settings with a slot tip. The powder coating
compositions were sprayed at 40-50% relative humidity. The powder
coating compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. to cure and
form the coatings.
[0138] The coated substrates were tested by the R-value and average
edge coverage tests previously described herein. The test results
of the R-value and average edge coverage are listed in Table
13.
TABLE-US-00013 TABLE 13 .mu.m Average R-value R-value edge .mu.m
Average Powder chemistry/ untreated treated coverage edge coverage
surface treatment top bottom untreated top treated bottom Acid
Epoxy/catalyst 3.8 3.1 2.8 10.2 Epoxy phenol/ 3.5 3.3 7.6 12.5
catalyst Acid 3.8 3.6 17.8 22.5 Hydroxyalkylamide/ crosslinker
[0139] As shown in Table 13, the portions of the coated substrates
treated with catalyst or crosslinker exhibited good R-values and
improved edge coverage as compared to the untreated portions of the
coated substrates.
Example 26
Crosslink Density Evaluation
[0140] The solution containing the catalyst described in Example 10
and shown in Table 3 was applied to bare cold rolled steel panels,
4.times.12.times.0.32 inch available from ACT item #10161, that
were shear cut along the sides and bottom of the panel .about. 1/16
of an inch or less off to provide sharp edges for testing. The
sheared test panels were first cleaned with MEK solvent, then iron
phosphate pretreated with Chemfos.RTM. 51HD solution at 140.degree.
F. for 2 minutes, and finally rinsed with deionized water. The
bottom half of each panel was dipped into the treatment solution
for 20 seconds, dried for 2 minutes at 110.degree. C., and allowed
to cool to room temperature.
[0141] The substrates were then electrostatically sprayed with a
powder coating composition comprising a carboxylic acid functional
polyester, a triglycidyl isocyanurate cross-linker, and standard
additives and fillers using a Nordson LAD series electrostatic
spray system at 35 kV with 9 psi flow and 10 psi fluidization
settings with a slot tip. The powder coating compositions were
sprayed at 40-50% relative humidity. The powder coating
compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) at 375.degree. F. for the period of time
listed in Table 14.
[0142] The coated substrates were tested for crosslink density by
comparing the MEK double rubs of the treated portions and the MEK
double rubs of the untreated portions. The test results are listed
in Table 14.
TABLE-US-00014 TABLE 14 MEK double Rubs MEK double Rubs Bake
Conditions Untreated Area Treated Area 4 min. @ 375.degree. F. 18
Fail 282 Fail 6 min. @ 375.degree. F. 327 Fail 500 Mar no break 9
min. @ 375.degree. F. 500 Mar no break 500 Mar no break
[0143] As shown in Table 14, the portions of the coated substrates
treated with catalyst exhibited improved abrasion resistance to MEK
double rubs at shorter periods of time as compared to the untreated
portions of the coated substrates. The results show that the
portions of the coated substrates treated with catalyst provide
better crosslinking of the powder coating by decreasing interfacial
flow of the powder coating composition over the treated
substrate.
Example 27
Cure Rate Evaluation
[0144] Various solutions were tested for cure rates. Each solution
was prepared with the components list in Table 15.
TABLE-US-00015 TABLE 15 Comparative Catalyst Cross-linker
Cross-linker Cross-linker Example Example Example Example Example
Components (grams) (grams) (grams) (grams) (grams) Coating 2.0 2.0
2.0 2.0 2.0 components.sup.12 Tetrabutyl 0 0.04 0 0 0 phosphonium
bromide EPOCROS K- 0 0 0.1 0 0 2030E.sup.3 CARBODILIT V- 0 0 0 0.1
0 02-L2.sup.4 Cardolite NX- 0 0 0 0 0.08 8101.sup.9 .sup.12A
carboxylic acid functional polyester, a triglycidyl isocyanurate
crosslinker, and standard additives and fillers.
[0145] Each solution described in Table 15 was measured into a
vessel on a 180.degree. C. hot plate. Gel times were measured by
mixing the material on the hot plate with a tongue depressor until
a gel was formed. A gel was recognized by long strings formed when
pulling the mixing stick away from the material on the hot plate.
The gel times of each solution is listed in Table 16.
TABLE-US-00016 TABLE 16 Comparative Catalyst Cross-linker
Cross-linker Cross-linker Example Example Example Example Example
180.degree. C. hot plate 142 9 8 7 20 gel times (seconds)
[0146] As shown in Table 16, the solutions containing the
crosslinkers and catalyst exhibited faster gel times as compared to
the solutions without the crosslinkers or catalyst. The results
show that the portions of the coated substrates treated with
catalyst provide faster crosslinking of the powder coating and
would therefore result in decreased interfacial flow and increased
viscosity of the powder coating composition when applied over a
substrate treated with the crosslinker or catalyst.
Example 28
Crosslink Degree Evaluation
[0147] The solutions containing the catalyst or crosslinkers
described in Examples 1-4 and shown in Table 1 were applied to bare
cold rolled steel panels, 4.times.12.times.0.32 inch available from
ACT item #10161. The test panels were first cleaned with MEK
solvent, then iron phosphate pretreated with Chemfos.RTM. 51HD
solution at 140.degree. F. for 2 minutes, and finally rinsed with
deionized water. Control panels with no treatments were dried for 2
minutes at 110.degree. C. Two panels for each treatment solution
were dipped half way into the respective treatment solution for 10
seconds. The panels were then pulled out of the solution, hung and
then dried for 2 minutes at 110.degree. C. and allowed to cool to
room temperature.
[0148] The substrates were then electrostatically sprayed with a
powder coating composition comprising a carboxylic acid functional
polyester, a triglycidyl isocyanurate cross-linker, and standard
additives and fillers using a Nordson LAD series electrostatic
spray system at 35 kV with 9 psi flow and 10 psi fluidization
settings with a slot tip. The powder coating compositions were
sprayed at 40-50% relative humidity. The powder coating
compositions were also applied on the front and back of the
substrates at a dry film thickness of 50 microns to 100 microns.
The powder coatings were heated in an electric oven (Despatch LAD
series electric oven) for 20 minutes at 375.degree. F. for one set
of panels and 5 minutes at 375.degree. F. for a second set of
panels. For testing, the panels were cut into small pieces (i.e.
smaller than 2 cm.times.2 cm) by a Hand Shear machine (model 24
hand shear, Di-Acro).
[0149] The coated substrates were first tested for degree of
crosslinking by a solvent soaking test. The solvent soaking test
was conducted on the 5 minute baked cut 2 cm.times.2 cm panels in
which the coating thickness retention of the coated substrates were
evaluated before solvent soaking the coated substrates and after
solvent soaking the coated substrates in acetone for 24 hours at
room temperature. Coating thickness retention was determined using
a 3D digital Macroscope. The test results are listed in Table
17.
TABLE-US-00017 TABLE 17 Control Catalyst Carbodiimide Oxazoline
Epoxy (no treatment) treatment.sup.13 Treatment.sup.14
Treatment.sup.15 treatment.sup.16 % Retention 0% 60.5% 43.8% 33.4%
12.8% coating weight .sup.13Solution from Example 1.
.sup.14Solution from Example 2. .sup.15Solution from Example 3.
.sup.16Solution from Example 4.
[0150] As shown in Table 17, complete removal of the coating was
observed upon acetone soaking the control sample not treated with
catalyst or crosslinker. The coating thickness retention was better
for the samples treated with catalyst and crosslinker demonstrating
a higher degree of crosslinking throughout the coating.
[0151] The degree of crosslinking was also evaluated using
thermomechanical analysis. For the testing, a Q400 thermomechanical
analyzer from TA Instruments Inc. was utilized to investigate the
cross linked structure by monitoring temperature-driven penetration
behavior. A constant ramp of 10.degree. C./min with a fixed force
of 0.1 N were applied in the temperature range of 25.degree.
C.-150.degree. C. The force was maintained until the system cooled
down below 25.degree. C.
[0152] At the short bake time of 5 min for 375.degree. F., the
control sample with no treatment exhibited a full penetration of
the entire coating at the temperature range in between 80.degree.
C. and 140.degree. C. In contrast, all the samples that were
treated with catalyst or crosslinker showed partial penetration or
two step partial penetration behavior, which demonstrate that the
samples treated with catalyst and crosslinker led to higher
viscosity (i.e. slower penetration rate) of the powder coating
composition as compared to the control due to higher crosslinking
degree.
[0153] Delamination was also evaluated when the samples were cut
into small pieces as previously described. At the short bake time
of 5 min for 375.degree. F., the control sample exhibited
pronounced delamination upon cutting. In contrast, no delamination
was observed for the samples treated with catalyst and crosslinker,
which further illustrates the higher levels of crosslinking.
[0154] The penetration traces of each sample were also preserved
and the details of the traces were evaluated with a Macroscope. The
image analysis results showed better coating at the edge for the
short bake time of 5 min for 375.degree. F. of the samples treated
with catalyst and crosslinker as compared to the control sample,
which further confirms better crosslinking.
[0155] The present invention also relates to the following
clauses.
[0156] Clause 1: A substrate comprising: (a) a first material
applied to at least a portion of the substrate; and (b) a
continuous film deposited from a curable powder coating composition
comprising a film forming resin having functional groups and a
crosslinker that is reactive with the functional groups of the film
forming resin in contact with at least a portion of the substrate
to which the first material has been applied, wherein the first
material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition, and/or (iii) a rheology modifier.
[0157] Clause 2: The substrate of clause 1, wherein the interfacial
flow of the liquidized powder coating composition in contact with a
portion of the substrate to which the first material has been
applied is lower than the interfacial flow of the same powder
composition liquidized under the same conditions that is in contact
with an identical substrate with the exception that no first
material has been applied or with a portion of the same substrate
to which the first material has not been applied.
[0158] Clause 3: The substrate of any of the preceding clauses,
wherein the viscosity of the liquidized powder coating composition
upon and/or after contact with the first material is higher than
the viscosity of the same powder coating composition liquidized
under the same conditions without contact to the first
material.
[0159] Clause 4: The substrate of any of the preceding clauses,
wherein the first material is localized at the interface where the
powder coating composition comes into contact with the first
material.
[0160] Clause 5: The substrate of any of clauses 1 to 3, wherein
the first material migrates into at least a portion of the powder
coating composition.
[0161] Clause 6: The substrate of any of the preceding clauses,
wherein the first material is the catalyst that catalyzes cure of
the powder coating composition.
[0162] Clause 7: The substrate of any of clauses 1 to 5, wherein
the first material is the component reactive with the film-forming
resin and/or the crosslinker of the powder coating composition.
[0163] Clause 8: The substrate of clause 7, wherein the first
material comprises a crosslinker, a resin, a reactive diluent, a
monomer, or a combination thereof that is reactive with the
film-forming resin and/or the crosslinker of the powder coating
composition.
[0164] Clause 9: The substrate of any of clauses 1 to 5, wherein
the first material is the rheology modifier.
[0165] Clause 10: The substrate of clause 9, wherein the rheology
modifier comprises silica, chemically modified silica, alumina,
chemically modified alumina, a hydrophobically modified
ethylene-oxide polymer, or any combination thereof.
[0166] Clause 11: The substrate of any of the preceding clauses,
wherein the first material prior to application is dispersed or
dissolved in a liquid medium.
[0167] Clause 12: The substrate of clause 11, wherein the liquid
medium is an aqueous liquid medium.
[0168] Clause 13: The substrate of any of the preceding clauses,
wherein the first material is applied directly over at least a
portion of the substrate.
[0169] Clause 14: The substrate of any of the preceding clauses,
wherein the first material is included in a pretreatment
composition applied to at least a portion of the substrate.
[0170] Clause 15: The substrate of clause 14, wherein there is a
greater concentration of the first material in a surface region of
the pretreatment composition applied to at least a portion of the
substrate than a bulk region of the pretreatment composition
applied to at least a portion of the substrate.
[0171] Clause 16: The substrate of any of clauses 1-12, wherein the
substrate further comprises a pretreatment layer and the first
material is applied over at a least portion of the pretreatment
layer.
[0172] Clause 17: The substrate of claim 1-12, wherein the
substrate further comprises a coating layer and the first material
is applied over at a least portion of the coating layer.
[0173] Clause 18: The substrate of any of the preceding clauses,
wherein after application to the substrate, at least a portion of
the powder coating composition has a pill flow rate of greater than
30 mm as measured by the pill flow test.
[0174] Clause 19: The substrate of any of the preceding clauses,
wherein the powder coating composition is physisorbed onto the
substrate.
[0175] Clause 20: The substrate of any of clauses 1-18, wherein the
first material is physisorbed on the substrate.
[0176] Clause 21: The substrate of any of the preceding clauses,
wherein the first material is chemisorbed on the substrate.
[0177] Clause 22: The substrate of any of the preceding clauses,
further comprising a second coating composition applied over at
least a portion of a coating formed from the powder coating
composition of (b).
[0178] Clause 23: The substrate of any of the preceding clauses,
wherein the substrate comprises cold rolled steel, hot rolled
steel, steel coated with zinc metal, zinc compounds, zinc alloys,
electrogalvanized steel, hot-dipped galvanized steel, galvanealed
steel, steel plated with zinc alloy, stainless steel,
zinc-aluminum-magnesium alloy coated steel, aluminum, aluminum
alloys, aluminum plated steel, aluminum alloy plated steel,
magnesium, magnesium alloys, nickel, brass, copper, silver, gold,
plastic, or any combination thereof.
[0179] Clause 24: The substrate of any of the preceding clauses,
wherein the substrate is a fastener, coiled metal, a vehicle, a
package, a heat exchanger, a vent, an extrusion, roofing, flooring,
a wheel, a grate, a belt, a conveyor, an aircraft, an aircraft
component, a vessel, a marine component, a vehicle, a building, an
electrical component, a grain or seed silo, wire mesh, a screen or
grid, HVAC equipment, a frame, a tank, a cord, a wire, or any
combination thereof.
[0180] Clause 25: A method for treating a substrate: (a) contacting
at least a portion of the substrate with a first material; (b)
directly contacting at least a portion of the substrate in contact
with the first material with a powder coating composition
comprising a film forming resin having functional groups and a
crosslinker that is reactive with the functional groups of the film
forming resin, and (c) liquidizing the powder coating composition
to form a continuous film of the powder coating composition on the
substrate, wherein the first material is (i) a catalyst that
catalyzes cure of the powder coating composition, (ii) a component
reactive with the film-forming resin and/or the crosslinker of the
powder coating composition, and/or (iii) a rheology modifier.
[0181] Clause 26: The method of clause 25, wherein step (a)
comprises dipping the substrate in a bath that comprises the first
material.
[0182] Clause 27: The method of clause 26, wherein the bath
comprises a pretreatment bath.
[0183] Clause 28: The method of clause 27, wherein the pretreatment
bath is a cleaner bath, a deoxidizer bath, a cleaner-coater bath, a
rinse conditioner bath, a pretreatment coating bath, a rinsing
bath, a sealing bath, or a deionized water rinsing bath.
[0184] Clause 29: The method of clause 25, wherein the first
material is contained on and/or in a wipe and step (a) comprises
wiping the substrate.
[0185] Clause 30: The method of clause 25, wherein the first
material is contained in a liquid formulation and the liquid
formulation is sprayed onto the substrate in step (a).
[0186] Clause 31: The method of clause 30, wherein the liquid
formulation further comprises a surfactant.
[0187] Clause 32: The method of clause 25, wherein the first
material is deposited onto the substrate by electrodeposition or
vapor deposition in step (a).
[0188] Clause 33: The method of clause 25, wherein the first
material is bushed or rolled onto the substrate in step (a).
[0189] Clause 34: The method of clause 25, wherein the first
material is a solid and is blasted onto the substrate in step
(a).
[0190] Clause 35: The method of clause 25, wherein the substrate is
cleaned and coated with the first material in a single step.
[0191] Clause 36: The method of clause 25, wherein the substrate is
plated with a metal prior to step (a).
[0192] Clause 37: The method of clause 25, wherein the substrate
comprises an anodized, cast, or forged metal.
[0193] Clause 38: The method of any of the clauses 25-37, wherein
first material is applied directly to the substrate.
[0194] Clause 39: The method of any of clauses 25-37, wherein the
substrate is treated prior to step (a).
[0195] Clause 40: The method of clause 39, wherein, prior to step
(a), the substrate is alkaline cleaned, deoxidized, mechanically
cleaned, ultrasonically cleaned, plasma cleaned or etched, exposed
to chemical vapor deposition, treated with an adhesion promoter, or
any combination thereof.
[0196] Clause 41: The method of clause 39, wherein the substrate is
pretreated prior to step (a) with a pretreatment composition.
[0197] Clause 42: The method of clause 41, wherein the pretreatment
composition comprises a sol-gel, iron phosphate, manganese
phosphate, zinc phosphate, a rare earth metal, permanganate,
zirconium, titanium, a silane, trivalent chrome (TCP), chromate,
metal oxide, hydrotalcite, phosphonic acid, layered double
hydroxide, or any combination thereof.
[0198] Clause 43: The method of clauses 41 or 42, wherein, after
pretreatment, the substrate is rinsed with, sprayed with, or wiped
with a solution that comprises the first material in step (a).
[0199] Clause 44: The method of any of clauses 41-43, wherein the
pretreatment composition is dried after application.
[0200] Clause 45: The method of any of clauses 25 to 44, further
comprising step (c), contacting at least a portion of the substrate
with a second coating composition.
[0201] Clause 46: The method of any of the clauses 25 to 45,
wherein the first material is dried by air and/or heat after step
(a).
[0202] Clause 47: The method of any of clauses 25-46, wherein there
is no intervening step between step (a) and step (b).
[0203] Clause 48: The method of any of clauses 25-47, wherein the
dry film thickness of the coating formed from the powder coating
composition at the edge of the substrate is 2 .mu.m or greater.
[0204] Clause 49: A method for treating a coil comprising: (a)
contacting at least a portion of the coil with a first material;
(b) rolling the coil; (c) unrolling the coil; (d) directly
contacting at least a portion of the coil in contact with the first
material with a powder coating composition comprising a film
forming resin having functional groups and a crosslinker that is
reactive with the functional groups of the film forming resin, and
(e) liquidizing the powder coating composition to form a continuous
film of the powder coating composition on the coil, wherein the
first material is (i) a catalyst that catalyzes cure of the powder
coating composition, (ii) a component reactive with a film-forming
resin and/or a crosslinker of the powder coating composition,
and/or (iii) a rheology modifier.
[0205] Whereas particular embodiments of this invention have been
described above for purposes of illustration, it will be evident to
those skilled in the art that numerous variations of the details of
the present invention may be made without departing from the
invention as defined in the appended claims.
* * * * *