U.S. patent application number 10/862243 was filed with the patent office on 2004-11-11 for adhesion promoting surface treatment or surface cleaner for metal substrates.
Invention is credited to Jennings, Robert E., Walters, David N..
Application Number | 20040224168 10/862243 |
Document ID | / |
Family ID | 25536210 |
Filed Date | 2004-11-11 |
United States Patent
Application |
20040224168 |
Kind Code |
A1 |
Jennings, Robert E. ; et
al. |
November 11, 2004 |
Adhesion promoting surface treatment or surface cleaner for metal
substrates
Abstract
A coating composition comprising a phenolic resin, an alkoxy
silane, and an acid. The coating composition of the present
invention promotes adhesion between a multiple layer coating
composition and a substrate and between the respective layers of
the multiple layer coating composition.
Inventors: |
Jennings, Robert E.;
(Ellwood City, PA) ; Walters, David N.; (Slippery
Rock, PA) |
Correspondence
Address: |
PPG INDUSTRIES INC
INTELLECTUAL PROPERTY DEPT
ONE PPG PLACE
PITTSBURGH
PA
15272
US
|
Family ID: |
25536210 |
Appl. No.: |
10/862243 |
Filed: |
June 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10862243 |
Jun 7, 2004 |
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09990492 |
Nov 21, 2001 |
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6774168 |
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Current U.S.
Class: |
428/447 ;
427/402; 528/25 |
Current CPC
Class: |
Y10T 428/31663 20150401;
C08K 5/09 20130101; C08K 5/09 20130101; C08K 5/54 20130101; C08K
5/5415 20130101; C09D 161/06 20130101; C08K 5/52 20130101; C08K
5/54 20130101; C08L 61/06 20130101; C08L 61/06 20130101; C08L 61/06
20130101 |
Class at
Publication: |
428/447 ;
427/402; 528/025 |
International
Class: |
B32B 015/08; B05D
007/00 |
Claims
1-31. (canceled).
32. A substrate coated with a coating composition comprising: a. a
phenolic resin; b. an alkoxysilane; and c. an acid.
33. The substrate of claim 32 wherein the substrate comprises cold
rolled steel, electrogalvanized steel, or aluminum.
34. The substrate of claim 32, wherein the coating composition is
applied to the substrate at a film thickness of no more than about
0.1 mils.
35. A method for coating a substrate comprising the following
steps: a. applying to the substrate a coating composition
comprising a phenolic resin, an alkoxysilane, and an acid; b.
optionally applying a primer coating over the coating composition
applied in step (a); and c. applying a topcoat over the coating
composition applied in step (a) or the primer coating applied in
optional step (b).
36. The method of claim 35 wherein the alkoxysilane comprises an
epoxy functional silane.
37. The method of claim 35 wherein the acid is selected from the
group consisting of tannic acid, phosphoric acid, citric acid, and
gallic acid and mixtures thereof.
38. The method of claim 35 wherein the phenolic resin is prepared
by condensing a phenolic material with an aldehyde.
39. The method of claim 35 wherein said phenolic resin is present
in an amount ranging from 0.1 to 99.8 percent by weight based on
the total weight of the coating composition.
40. The method of claim 35 wherein said alkoxysilane is present in
an amount ranging from 0.1 to 99.8 percent by weight based on the
total weight of the coating composition.
41. The method of claim 35 wherein said acid is present in an
amount ranging from 0.1 to 99.8 percent by weight based on the
total weight of the coating composition.
42. The substrate of claim 32, wherein the alkoxy group of the
alkoxysilane contains from 1 to 6 carbon atoms.
43. The substrate of claim 32, wherein the alkoxysilane comprises
an epoxy functional silane.
44. The substrate of claim 32, wherein the acid is selected from
the group consisting of tannic acid, phosphoric acid, citric acid,
and gallic acid and mixtures thereof.
45. The substrate of claim 32, wherein the phenolic resin has an
aromaticity of from 15 to 80 percent.
46. The substrate of claim 32, wherein the alkoxysilane is selected
from the group consisting of acryloxyalkoxysilanes, vinyl
alkoxysilanes, ethylenically unsaturated acyloxysilanes, mercapto
functional silanes, and amino functional silanes.
47. The method of claim 35, wherein the alkoxy group of the
alkoxysilane contains from 1 to 6 carbon atoms.
48. The method of claim 35, wherein the phenolic resin has an
aromaticity of from 15 to 80 percent.
49. The method of claim 35, wherein the alkoxysilane is selected
from the group consisting of acryloxyalkoxysilanes, vinyl
alkoxysilanes, ethylenically unsaturated acyloxysilanes, mercapto
functional silanes, and amino functional silanes.
50. The method of claim 35, wherein the substrate comprises cold
rolled steel, electrogalvanized steel, or aluminum.
51. The method of claim 35, wherein the coating composition applied
in step (a) is applied at a thickness of no more than about 0.1
mils.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to compositions and methods
for treating a substrate to promote adhesion, particularly
compositions and methods for treating substrates that contain
multiple layers of coating compositions.
BACKGROUND
[0002] It is difficult to formulate coating compositions that can
adequately adhere to various substrates like untreated steel,
galvanized steel and aluminum because different substrates have
widely varying surface properties. Primers can be applied to a
substrate in order to increase the ability of a coating composition
to adhere to the substrate, but a single primer is usually not
effective on different types of substrates.
[0003] A conversion coating can be applied to a substrate in order
to improve a coating composition's ability to adhere to the
substrate. Conversion coatings which deposit as a microthin coating
and react with the substrate come in two types. The first and most
common type is an aqueous solution of strong mineral acids which
enhances adhesion by chemically reacting with the metallic
substrates in a process called "etching". A drawback of aqueous
conversion coatings is that it is difficult to uniformly apply one
over a substrate.
[0004] The second type of conversion coating is a dispersion in
organic solvents. For optimum performance, this type of conversion
coating often contains heavy metal pigments such as strontium
chromate. The negatives of conversion coatings dispersed in organic
solvents are twofold. First, they are not effective on a wide range
of substrates. Second, they are hazardous to the environment
because they often contain heavy metal pigments.
[0005] The present invention provides a coating composition that
promotes adhesion between a multiple layer coating composition and
a substrate and between the respective layers of the multiple layer
coating composition. Further, the coating composition of the
present invention is easy to apply, can be used on various
substrates, and is not harmful to the environment.
SUMMARY OF THE INVENTION
[0006] The present invention is a coating composition comprising a
phenolic resin, an alkoxy silane, and an acid.
[0007] The present invention is also a method for coating a
substrate comprising the following steps:
[0008] a. applying a controlled thickness of a coating composition
comprising a phenolic resin, an alkoxy silane, and an acid;
[0009] b. optionally applying a primer coating over the coating
applied in step (a); and
[0010] c. a topcoat over the coating applied in step (a) or in
optional step (b).
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present invention is directed to a coating composition
capable of promoting adhesion between a multiple layer coating
composition and a substrate, especially aluminum, and between the
respective layers of the multiple layer coating composition when
applied at a very low film thickness. The coating composition of
the present invention comprises a phenolic resin. Phenolic resins,
commonly referred to as phenoplasts, can be prepared by the
condensation of a phenol or an alkyl substituted phenol with an
aldehyde. Suitable phenols include, but are not limited to,
monohydric phenols like cresol and xylenol and polyhydric phenols
like resorcinol. Suitable aldehydes include, but are not limited
to, formaldehyde, acetaldehyde, butyraldehyde and
furfuraldehyde.
[0012] Suitable phenolic resins and methods for preparing them are
disclosed in U.S. Pat. No. 6,028,133 issued to Peek and U.S. Pat.
No. 6,114,491 issued to Dupre. Commercially available phenolic
resins like GPRI BLS2700 from Georgia Pacific Corporation, Methylon
75108 from Occidental Chemical Corp., and Phenodur PR 263 from
Vianova Resins, Inc. can be used in the present invention.
[0013] The aromaticity of the phenolic resin ranges from about 0 to
80 percent or 15 to 65 percent. The aromaticity can be determined
by IR spectrophotometry if not supplied by the vendor. The phenolic
resin is present in an amount ranging from about 0.1 to 99.8
percent where percents are based on the total resin solids weight
of the coating composition.
[0014] The invention also includes an alkoxysilane. Preferred
alkoxysilanes are acryloxyalkoxysilanes like
gamma-acryloxypropyltrimetho- xysilane and
methacrylatoalkoxysilanes like gamma-methacryloxypropyltrimet-
hoxysilane, gamma-methacryloxypropyltriethoxysilane and
gamma-methacryloxypropyltris (2-methoxyethoxy)silane. Due to its
greater reactivity, gamma-methacryloxypropyltrimethoxysilane is
especially preferred.
[0015] Other suitable alkoxysilanes include vinyl alkoxysilanes,
ethylenically unsaturated acyloxysilanes, mercapto functional
silanes, amino functional silanes, and epoxy functional silanes.
Exemplary vinyl alkoxysilanes include vinyltrimethoxysilane,
vinyltriethoxysilane and vinyltris(2-methoxyethoxy) silane.
Exemplary ethylenically unsaturated acyloxysilanes include
acrylato-, methacrylato- and vinyl-acetoxysilanes like
vinylmethyldiacetoxysilane, acrylatopropyltriacetoxysilane, and
methacrylatopropyltriacetoxysilane. Exemplary mercapto functional
silanes include gamma-mercaptopropyltrimethoxysilane,
gamma-mercaptopropyltrietho- xysilane, and
gamma-mercaptopropyltrisopropoxysilane. Exemplary amino functional
silanes include bis-(gamma-trimethoxysilylpropyl) amine,
N-phenyl-gamma-amino propyltrimethoxysilane, and
cyclohexyl-gamma-aminopr- opyltrimethoxysilane. Exemplary epoxy
functional silanes include
beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and
gamma-glycidoxypropyltrimethoxysilane.
[0016] The alkoxysilanes may be polymeric like an acrylic polymer
containing a plurality of alkoxysilane groups. Alkoxysilane
functional acrylic polymers can be prepared by copolymerizing
various ethylenically unsaturated alkoxy functional monomers such
as the acryloxysilanes mentioned above with other ethylenically
unsaturated monomers via solution polymerization techniques in the
presence of suitable initiators. The polymerization is carried out
in an organic solution utilizing techniques which are well known in
the art. Examples of alkoxysilane functional acrylic polymers are
disclosed in U.S. Pat. No. 4,614,777.
[0017] The alkoxysilanes of the present invention have a molecular
weight ranging from about 136 to 50,000 or from about 136 to
600.
[0018] The coating composition of the present invention further
comprises an acid. One suitable acid is tannic acid or tannin.
Tannins are extracted from various plants and trees which can be
classified according to their chemical properties as (a)
hydrolyzable tannins, (b) condensed tannins, and (c) mixed tannins
containing both hydrolyzable and condensed tannins. Preferred
tannin materials useful in the present invention are those that
contain a tannin extract from naturally occurring plants and trees,
and are normally referred to as vegetable tannins. Suitable
vegetable tannins include the crude, ordinary or hot-water-soluble
condensed vegetable tannins. Quebracho and mimosa are the preferred
condensed vegetable tannins. Other vegetable tannins include
mangrove, spruce, hemlock, gabien, wattles, catechu, uranday, tea,
larch, myrobalan, chestnut wood, divi-divi, valonia, summac,
chinchona, oak, etc. These vegetable tannins are not pure chemical
compounds with known structures, but rather contain numerous
components including phenolic moieties such as catechol,
pyrogallol, etc., condensed into a complicated polymeric
structure.
[0019] An example of another suitable acid is phosphoric acid. The
phosphoric acid can be a 100 percent orthophosphoric acid,
superphosphoric acid or the aqueous solutions thereof, such as 85
percent phosphoric acid solution. Typically, aqueous phosphoric
acid solutions which are about 70 to 90 percent phosphoric acid are
used.
[0020] The amount of acid typically used in the practice of the
present -invention ranges from about 0.1 to 99.8 percent where
percents are based on total weight of resin solids.
[0021] Optionally, the coating composition of the present invention
can include solvents, rheological agents, and pigments. Suitable
solvents include aromatic petroleum distillates like toluene,
xylene, and aromatic blends commercially available from Exxon
Corporation like SOLVESSO 100 and SOLVESSO 150; aliphatic solvents
like cyclohexane and naphtha's; ketone solvents like acetone,
methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl
ketone; alcohols like ethyl alcohol, propyl alcohol, and diacetone
alcohol; mono- and dialkyl ethers of ethylene and diethylene glycol
like ethylene glycol monoethyl ether, ethylene glycol monobutyl
ether, ethylene glycol monoethyl ether acetate, diethylene glycol
monobutyl ether, and diethylene glycol diethyl ether.
[0022] Because the coating composition of the present invention is
a universal pretreatment, it can be used on a variety of substrates
such as cold rolled steel (CRS), electrogalvanized steel (EG), and
aluminum (AL).
[0023] The coating composition of the present invention can be
applied in the following manner. First, clean the substrate to
remove any dirt, grease, or machine oils that may be present on the
substrate before applying the coating composition. A suitable
cleaning agent is DX330, which is commercially available from PPG
Industries, Inc. After the substrate is cleaned, it can be sanded.
Although sanding is not required, it can lead to enhanced adhesion
performance. Lastly, apply the coating composition.
[0024] Typically, the coating composition of the present invention
is packaged as two separate components which are mixed prior to
application. The components are. typically formulated such that
they are mixed 1:1 by volume and then applied to the substrate. One
method for applying the coating composition involves wetting a
clean towel with the coating composition and then lightly wiping
the substrate using the towel to remove excess coating. The
composition can also be applied via spray with an air supplied
spray gun or a garden spray type apparatus. If the coating
composition is sprayed on, it is recommended that the substrate be
wiped down with a clean towel or a towel wetted with pretreatment
to remove excess coating.
[0025] The applied coating film should be a very thin, transparent
film. The dry film thickness is typically no more than
approximately 0.1 mils. Typically, the dry film thickness is in the
range of 0.01 to 0.1 mils.
[0026] After the coating composition of the present invention is
applied, the coating can receive a primer coating followed by a
topcoat layer or receive a topcoat without a primer coating.
Examples of suitable primer coatings are described in U.S. Pat. No.
5,468,802. The dry film thickness of the primer layer generally
ranges from about 0.5 to 5 mils, and the dry film thickness of the
topcoat layer generally ranges from about 1 to 5 mils.
[0027] The present invention provides for enhanced adhesion of
multiple layers of coatings to a variety of substrates and to each
other.
EXAMPLES
[0028] The present invention will now be illustrated by the
following non-limiting examples. Various coating compositions of
the present invention and other comparative compositions were
prepared for the purposes of testing. The various coating
compositions are denoted as Examples 1 through 10. Tables 1 through
11 summarize the adhesion performance of the exemplarary coating
compositions and a control on various substrates both sanded and
unsanded over varying periods of time.
The Coating Compositions
[0029] The Example compositions utilized in the present invention
were prepared in the following manner. The numbers which appear
below are weight percentages based on the total weight of the
composition.
Example 1
[0030] To prepare Example 1, tannic acid was dissolved in a mixture
of methyl ethyl ketone, ethanol, and xylene. A phenolic resin
solution which is commercially available as GPRI BLS2700 from
Georgia Pacific Corporation was then added to the solution. The
phenolic resin was a condensate of phenol with a resin solids
content of 56% in ethanol and a 55% aromaticity. The specific
makeup of the composition is as follows:
1 GPRI BLS2700 16.273% Tannic acid 0.090% Methyl ethyl ketone
49.691% Ethanol 24.845% Xylene 8.282%
Example 2
[0031] Example 2 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, tannic acid was dissolved in a mixture of methyl ethyl
ketone, ethanol, and xylene. To prepare the second component, a
gamma-glycidoxypropyl-trimetho- xyl silane which is commercially
available as Silquest A-187 from OSi Specialties, Inc. was diluted
with a solvent mixture of methyl ethyl ketone, ethanol, xylene, and
1,4, pentanedione. The first component and second component,
respectively, were made up as follows.
[0032] First Component
2 Tannic acid 1.0% Methyl ethyl ketone 5.4% Ethanol 2.7% Xylene
0.9%
[0033] Second Component
3 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4, pentanedione 4%
Example 3
[0034] Example 3 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, GPRI BLS-2700 was diluted in a solvent mixture of methyl
ethyl ketone, ethanol, and xylene. To prepare the second component,
Silquest A-187 was diluted within a solvent mixture of methyl ethyl
ketone, ethanol, xylene, and 1,4 pentanedione. The first component
and the second component, respectively, were made up as
follows.
[0035] First Component
4 GPRI BLS-2700 18% Methyl ethyl ketone 49% Ethanol 25% Xylene
8%
[0036] Second Component
5 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 4
[0037] Example 4 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, tannic acid was dissolved in a solvent mixture of methyl
ethyl ketone, ethanol, and xylene. GPRI BLS-2700 was then added to
complete the solution. To prepare the second component, Silquest
A-187 was diluted with a solvent mixture of methyl ethyl ketone,
ethanol, xylene, and 1,4 pentanedione. The first component and the
second component, respectively, were made up as follows.
[0038] First Component
6 GPRI BLS-2700 16% Tannic acid 1% Methyl ethyl ketone 50% Ethanol
25% Xylene 8%
[0039] Second Component
7 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 5
[0040] Example 5 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, an 85% phosphoric acid aqueous solution was diluted in a
solvent mixture of methyl ethyl ketone, ethanol, and xylene. Then
GPRI BLS-2700 was added to the solution. To prepare component 2,
Silquest A-187 was diluted with a solvent mixture of methyl ethyl
ketone, ethanol, xylene, and 1,4 pentanedione. The first component
and the second component, respectively, were made up as
follows.
[0041] First Component
8 GPRI BLS-2700 16% 85% phosphoric acid aqueous solution 1% Methyl
ethyl ketone 50% Ethanol 25% Xylene 8%
[0042] Second Component
9 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 6
[0043] Example 6 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, citric acid was dissolved in methanol. A solvent mixture
of methyl ethyl ketone, ethanol, and xylene was then added to the
solution. Lastly, GPRI BLS-2700 was added to the solution. To
prepare the second component, Silquest A-187 was diluted in a
solvent mixture of methyl ethyl ketone, ethanol, xylene, and 1,4
pentanedione. The first component and the second component,
respectively, were made up as follows.
[0044] First Component
10 Citric acid 1% Methanol 8% Methyl ethyl ketone 45% Ethanol 22%
Xylene 7% GPRI BLS-2700 16%
[0045] Second Component
11 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 7
[0046] Example 7 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, a vinyl resin commercially available as UCAR Solution
Vinyl Resin VAGH from Union Carbide Chemicals and Plastics Co. Inc.
and tannic acid were dissolved in mixture of methyl ethyl ketone,
ethanol, and xylene. GPRI BLS-2700 was added to the solution. To
prepare the second component, Silquest A-187 was diluted in a
solvent mixture of methyl ethyl ketone, ethanol, xylene, and
1,4-pentanedione. The first component and the second component,
respectively, were made up as follows.
[0047] First Component
12 GPRI BLS-2700 15% UCAR Solution Vinyl Resin VAGH 1% Tannic Acid
1% Methyl ethyl ketone 50% Ethanol 25% Xylene 8%
[0048] Second Component
13 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 8
[0049] Example 8 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, tannic acid was dissolved in mixture of methyl ethyl
ketone, ethanol, and xylene. A phenolic resin, which is
commercially available as Methylon 75108 from Occidental Chemical
Corp., was added to the solution. Methylon 75108 was a condensate
of 3-chloro-l-propene phenol with a resin solids content of 100%
and a 24% aromaticity. To prepare the second component, Silquest
A-187 was diluted in a solvent mixture of methyl ethyl ketone,
ethanol, xylene, and 1,4 pentanedione.. The first component and the
second component, respectively, were made up as follows.
[0050] First Component
14 Tannic acid 1% Methyl ethyl ketone 54% Ethanol 27% Xylene 9%
Methylon 75108 9%
[0051] Second Component
15 Silquest A-187 10% Methyl ethyl ketone 53% Ethanol 26% Xylene 9%
1,4 pentanedione 2%
Example 9
[0052] Example 9 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, tannic acid was dissolved in mixture of methyl ethyl
ketone, ethanol, and xylene. A phenolic resin, which is
commercially available as Phenodur PR 263 from Vianova Resins,
Inc., was added to the solution. Phenodur PR 263 was a condensate
of phenol with a number average molecular weight of 780, a solids
content of 70% in butanol, and 20% aromaticity. To prepare the
second component, Silquest A-187 was diluted in a solvent mixture
of methyl ethyl ketone, ethanol, xylene, and 1,4 pentanedione. The
first component and the second component, respectively, were made
up as follows.
[0053] First Component
16 Tannic acid 1% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
Phenodur PR 263 13%
[0054] Second Component
17 Silquest A-187 10% Methyl ethyl ketone 51% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Example 10
[0055] Example 10 was comprised of two components which were
combined immediately prior to application. To prepare the first
component, tannic acid was dissolved in a solvent mixture of methyl
ethyl ketone, ethanol, and xylene. GPRI BLS-2700 was then added to
complete the solution. To prepare the second component, Silquest
A-187 was diluted with a solvent mixture of methyl ethyl ketone,
ethanol, xylene, and 1,4 pentanedione. The first component and the
second component, respectively, were made up as follows.
[0056] First Component
18 GPRI BLS-2700 16% Tannic acid 1% Methyl ethyl ketone 50% Ethanol
25% Xylene 8%
[0057] Second Component
19 Silquest A-187 9% Methyl ethyl ketone 52% Ethanol 26% Xylene 9%
1,4 pentanedione 4%
Preparation of the Coated Substrates
[0058] The coating compositions of the present invention were
tested on the following substrates; electrogalvanized substrates,
cold rolled steel substrates, and aluminum substrates. The
electrogalvanized, cold rolled steel, and aluminum substrates are
commercially available as APR18661, APR10288, and APR19081 or
APR10326, respectively, from ACT Laboratories, Inc.
[0059] Both sanded and unsanded substrates were tested. The sanding
was done with 180 grit sandpaper which is commercially available as
3M Stikit Gold Disc Roll from 3M Corporation.
[0060] Substrates coated with the Example compositions 1-6 were
prepared as follows. The substrate was initially wiped with a
lint-free tissue soaked with a cleaner/degreaser which is
commercially available as DX330 from PPG Industries, Inc. The
substrate was then allowed to air dry. The components of the
specific Examples were mixed at equal volumes and applied to both a
sanded and an unsanded side of the substrate. The coating
composition was applied by wetting a lint-free tissue which is
commercially available as Precision Wipes from Kimberly Clark
Corporation and then lightly wiping the substrate with the
lint-free tissue. After an approximately five minute flash, the
coated substrate was primed with a polyisocyanate primer-sealer
which is commercially available as K36 Sealer from PPG Industries,
Inc. After one hour, a polyisocyanate cured topcoat which is
commercially available as Concept 9300 from PPG Industries, Inc.
was applied to the primed substrate.
[0061] Substrates coated with Example 7 were prepared as follows. A
panel (commercially available as APR22986 from ACT Laboratories,
Inc.) coated with a cationic electrocoat (ED 5000 from PPG
Industries, Inc.) was cleaned using a lint-free tissue soaked with
DX330. The substrate was allowed to dry, and the components of
Example 7 were mixed together at equal volumes. A lint-free tissue
was then wetted with the coating composition and lightly wiped over
the substrate. After an approximately five minute flash, the coated
substrate was primed with a two component primer-surfacer which is
commercially available as UNIPRIME D8042/D8240. One hour later, the
primed substrate was coated with Concept 9300.
[0062] Substrates coated with Examples 8 and 9 were prepared as
follows. The electrogalvanized and cold rolled steel substrates
were mechanically sanded with 180 grit paper. The aluminum
substrates were not sanded.
[0063] Next, the substrate was wiped with a lint-free tissue soaked
with DX330. Then, the specific coating composition was mixed at
equal volumes. A lint-free tissue. was wetted with the example
coating and lightly wiped over the substrate. After a five minute
flash, the coated substrate was primed with K36 Sealer. One hour
later, the substrate was coated with Concept 9300.
[0064] Substrates coated with Example 10 were prepared as follows.
The substrate was initially wiped with a lint-free tissue soaked
with a cleaner/degreaser which is commercially available as DX330
from PPG Industries, Inc. The substrate was then allowed to air
dry. The components of the specific Example were mixed at equal
volumes and applied to sanded substrate. The coating composition
was applied by wetting a lint-free tissue which is commercially
available as Precision Wipes from Kimberly Clark Corporation and
then lightly wiping the substrate with the lint-free tissue. After
an approximately five minute flash, the coated substrate was
topcoated with a polyisocyanate crosslinked alkyd topcoat which is
commercially available as AUE300/AUE301 from PPG Industries,
Inc.
Testing of the Coated Substrates
[0065] After 24 hours, all of the prepared substrates were
evaluated for adhesion using ASTM D3359, Method B. The substrates
were rated according to the percentage of coating retention.
[0066] One week later, the substrates were evaluated again. This
time duplicate substrates were used. One panel was tested as
described above and the other after being exposed for 96 hours to
100 percent humidity at 100.degree. F. The substrates were visually
inspected for blisters.
[0067] The results for each of the Example coatings and a control
(substrate primed with K36 sealer and, one hour later, coated with
Concept 9300; the coating composition of the present invention was
not applied) appear below in Tables 1-11
20TABLE 1 The Performance of Example 1 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 60 0 0 N Sanded EG APR10288- 40
0 0 N Sanded CRS APR19081- 10 0 0 N Sanded Al APR18661- 100 20 0 N
Unsanded EG APR10288- 90 0 0 N Unsanded CRS APR19081- 65 0 0 N
Unsanded AL
[0068]
21TABLE 2 The Performance of Example 2 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 100 100 100 N Sanded
Al APR18661- 100 100 100 N Unsanded EG APR10288- 100 100 100 N
Unsanded CRS APR19081- 100 100 0 N Unsanded AL
[0069]
22TABLE 3 The Performance of Example 3 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 25 95 100 N Sanded Al
APR18661- 100 100 82 N Unsanded EG APR10288- 95 100 0 N Unsanded
CRS APR19081- 0 0 0 Y Unsanded AL
[0070]
23TABLE 4 The Performance of Example 4 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 100 100 100 N Sanded
Al APR18661- 100 100 100 N Unsanded EG APR10288- 100 100 100 N
Unsanded CRS APR19081- 100 100 95 N Unsanded AL
[0071]
24TABLE 5 The Performance of Example 5 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 100 100 0 Y Sanded Al
APR18661- 100 100 100 N Unsanded EG APR10288- 100 100 100 N
Unsanded CRS APR19081- 95 90 95 N Unsanded AL
[0072]
25TABLE 6 The Performance of Example 6 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 90 60 100 N Sanded EG APR10288-
95 95 0 N Sanded CRS APR19081- 100 75 100 N Sanded Al APR18661- 100
95 100 N Unsanded EG APR10288- 100 100 0 Y Unsanded CRS APR19081-
55 45 0 Y Unsanded AL
[0073]
26TABLE 7 The Performance of Example 7 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 95 N Unsanded ED
5000
[0074]
27TABLE 8 The Performance of Example 8 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 0 0 0 Y Unsanded
Al
[0075]
28TABLE 9 The Performance of Example 9 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 100 100 0 Y Unsanded
Al
[0076]
29TABLE 10 Comparison of the Adhesion Performance of Substrates
Coated with Example 10 and the Same Substrates without the Coating
% Adhesion after % Adhesion after 1 week 96 hours at 100% humidity
Blistering Substrates Coated with Example 10 APR10288- 100 100 N
Sanded CRS APR10326- 100 100 N Sanded Al Same Substrates without
the Coating APR10288- 85 80 N Sanded CRS APR10326- 0 0 Y Sanded
Al
[0077]
30TABLE 9 The Performance of Example 9 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 100 100 100 N Sanded EG
APR10288- 100 100 100 N Sanded CRS APR19081- 100 100 0 Y Unsanded
Al
[0078]
31TABLE 10 Comparison of the Adhesion Performance of Substrates
Coated with Example 10 and the Same Substrates without the Coating
% Adhesion after % Adhesion after 1 week 96 hours at 100% humidity
Blistering Substrates Coated with Example 10 APR10288- 100 100 N
Sanded CRS APR10326- 100 100 N Sanded Al Same Substrates without
the Coating APR10288- 85 80 N Sanded CRS APR10326- 0 0 Y Sanded
Al
[0079]
32TABLE 11 Performance of the Control.sup.1 % Adhesion % Adhesion %
Adhesion after after after 96 hours at Substrate 24 hours 1 week
100% humidity Blistering APR18661- 0 0 0 N Sanded EG APR10288- 100
90 85 N Sanded CRS APR19081- 0 0 0 Y Sanded Al APR18661- 0 0 0 N
Unsanded EG APR10288- 100 0 0 N Unsanded CRS APR19081- 0 0 0 Y
Unsanded AL .sup.1The various substrates were primed with K36
sealer and, one hour later, coated with Concept 9300; the coating
composition of the present invention was not applied.
[0080] Conclusion
[0081] Regardless of the type of substrate, maximum adhesion is
achieved when a coating composition comprising a phenolic, and an
alkoxy silane, and an acid is applied.
* * * * *