U.S. patent application number 10/028839 was filed with the patent office on 2003-09-18 for polyether carbamate compounds, compositions containing such compounds, and methods related thereto.
Invention is credited to Hart, Michael P., Jia, Christiana Yichun, Pagac, Edward S., Swarup, Shanti, Taylor, Cathy A., Zezinka, Elizabeth A..
Application Number | 20030176592 10/028839 |
Document ID | / |
Family ID | 21845743 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030176592 |
Kind Code |
A1 |
Swarup, Shanti ; et
al. |
September 18, 2003 |
Polyether carbamate compounds, compositions containing such
compounds, and methods related thereto
Abstract
The present invention provides a reaction product having
polyether carbamate groups formed from (A) polyoxyalkylene amine,
and (B) cyclic carbonate, in an equivalents ratio ranging from
1:0.5 to 1:1.5. Further provided is a process for preparing the
aforementioned reaction product. The present invention also is
directed to an improved curable coating composition including (1) a
reactive functional group-containing polymer, and (2) a curing
agent having functional groups reactive with the functional groups
of (1), the improvement being the inclusion in the coating
composition the reaction product. Multilayer composite coatings
including a first coating layer formed from the curable coating
composition and a second coating layer over the curable coating
compostion are also provided, as well as coated substrates.
Inventors: |
Swarup, Shanti; (Allison
Park, PA) ; Hart, Michael P.; (Cleveland Heights,
OH) ; Jia, Christiana Yichun; (University Heights,
OH) ; Pagac, Edward S.; (Portersville, PA) ;
Taylor, Cathy A.; (Allison Park, PA) ; Zezinka,
Elizabeth A.; (Cranberry Township, PA) |
Correspondence
Address: |
PPG INDUSTRIES INC
INTELLECTUAL PROPERTY DEPT
ONE PPG PLACE
PITTSBURGH
PA
15272
US
|
Family ID: |
21845743 |
Appl. No.: |
10/028839 |
Filed: |
December 20, 2001 |
Current U.S.
Class: |
525/419 |
Current CPC
Class: |
Y10T 428/31855 20150401;
C08G 65/33344 20130101; C09D 201/025 20130101; C08G 65/331
20130101; C09D 175/16 20130101; C08G 71/04 20130101; C08G 18/5045
20130101; C08G 18/672 20130101; C08G 18/672 20130101; C08G 18/42
20130101 |
Class at
Publication: |
525/419 |
International
Class: |
C08G 063/91 |
Claims
We claim:
1. A reaction product comprising polyether carbamate groups, said
reaction product formed from: (A) at least one polyoxyalkylene
amine selected from the group consisting of polyoxyalkylene
monoamine, polyoxyalkylene diamine, polyoxyalkylene triamine, and
mixtures thereof, wherein the polyoxyalkylene diamine comprises a
compound having the following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.sup.2--NH.- sub.2
(I) where R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represent a C.sub.2 to C.sub.12
alkylene group, and (n+m) represents a value greater than 2,
provided that when R.sup.1 and R.sup.3 are different (n+m)
represents a value greater than or equal to 2; and (B) at least one
cyclic carbonate, wherein a ratio of equivalents of amine (A) to
equivalents of cyclic carbonate (B) ranges from 1:0.5 to 1:1.5.
2. The reaction product of claim 1, wherein the ratio of
equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.8 to 1:1.1.
3. The reaction product of claim 1, wherein the ratio of
equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.9 to 1:1.1.
4. The reaction product of claim 1, wherein at least a portion of
the reaction product is hydroxy-terminated.
5. The reaction product of claim 1, wherein R.sup.1, R.sup.2, and
R.sup.3 can be the same or different and each independently
represents an alkylene group selected from ethylene, propylene, and
butylene; and (n+m) represents a value greater than 2, provided
that when R.sup.1 and R.sup.3 are different, (n+m) is equal to or
greater than 2.
6. The reaction product of claim 1, wherein R.sup.1, R.sup.2, and
R.sup.3 can be the same or different and each independently
represents an alkylene group selected from ethylene and propylene,
and (n+m) represents a value greater than 2, provided that when
R.sup.1 and R.sup.3 are different, (n+m) is equal to or greater
than 2.
7. The reaction product of claim 6, wherein
5.ltoreq.(n+m).ltoreq.6.
8. The reaction product of claim 1, wherein the polyoxyalkylene
triamine comprises a triamine having the following structure (II)
or (III): 5or 6wherein R.sup.1, R.sup.2, and R.sup.3 independently
can be the same or different and each independently represents a
moiety selected from ethylene, propylene, and butylene, and x, y,
and z independently can be the same or different, and each
independently represents a value greater than or equal to 1.
9. The reaction product of claim 1, wherein the cyclic carbonate is
selected from the group consisting of ethylene carbonate, propylene
carbonate, butylene carbonate, glycerine carbonate, and mixtures
thereof.
10. The reaction product of claim 9 wherein the cyclic carbonate is
selected from at least one of ethylene carbonate, propylene
carbonate, and butylene carbonate.
11. A reaction product comprising polyether carbamate groups, said
reaction product formed from: (A) at least one polyoxyalkylene
amine, and (B) at least one cyclic carbonate selected from
propylene carbonate, butylene carbonate, glycerine carbonate, and
mixtures thereof, wherein a ratio of equivalents of amine (A) to
equivalents of cyclic carbonate (B) ranges from 1:0.5 to 1:1.5.
12. The reaction product of claim 11, wherein the ratio of
equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.8 to 1:1.1
13. The reaction product of claim 11, wherein the ratio of
equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.9 to 1:1.1.
14. The reaction product of claim 11, wherein the polyoxyalkylene
amine (A) is selected from the group consisting of polyoxyalkylene
monoamine, polyoxyalkylene diamine, polyoxyalkylene triamine, and
mixtures thereof.
15. The reaction product of claim 14, wherein the polyoxyalkylene
diamine comprises a compound having the following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.sup.2--NH.sub.2 (I)
where R.sup.1, R.sup.2, and R.sup.3 can be the same or different
and each independently represent a C.sub.2 to C.sub.12 alkylene
group, and (n+m) represents a value greater than 2, provided that
when R.sup.1 and R.sup.3 are different (n+m) represents a value
greater than or equal to 2
16. A reaction product prepared by the following steps: (a)
admixing at least one cyclic carbonate, and at least one polyether
amine selected from the group consisting of polyoxyalkylene
monoamine, polyoxyalkylene diamine, polyoxyalkylene triamine, and
mixtures thereof, wherein the polyoxyalkylene diamine comprises a
compound having the following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.sup.2--NH.- sub.2
(I) where R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represent a C.sub.2 to C.sub.12
alkylene group, and (n+m) represents a value greater than 2,
provided that when R.sup.1 and R.sup.3 are different (n+m)
represents a value greater than or equal to 2, optionally, in the
presence of an alkoxide catalyst, to form a reaction mixture such
that the ratio of equivalents of amine to equivalents of cyclic
carbonateis1:0.5 to 1:1.5; and (b) maintaining the reaction mixture
of step (a) at a temperature ranging from ambient temperature to
150.degree. C. at atmospheric pressure for a period of time
sufficient to drive the reaction to 80 percent of theoretical
completion.
17. The reaction product of claim 16, wherein the ratio of
equivalents of amine to equivalents of cyclic carbonate ranges from
1:0.8 to 1:1.1.
18. The reaction product of claim 16, wherein the temperature of
the reaction admixture is maintained between ambient temperature
and 150.degree. C. at atmospheric pressure for a period of time
sufficient to drive the reaction to 90 percent of theoretical
completion.
19. The reaction product of claim 16, wherein the polyoxyalkylene
triamine comprises a triamine having the following structure (VI)
or the structure (VII): 7wherein R.sup.1, R.sup.2, and R.sup.3
independently can be the same or different and each independently
represents a moiety selected from ethylene, propylene, and
butylene, and x, y, and z can be the same or different and each
independently represents a value greater than or equal to 1.
20. The reaction product of claim 16, wherein the cyclic carbonate
is selected from the group consisting of ethylene carbonate,
propylene carbonate, butylene carbonate, glycerine carbonate, and
mixtures thereof.
21. The reaction product of claim 16, wherein the cyclic carbonate
is selected from at least one of ethylene carbonate, propylene
carbonate, and butylene carbonate.
22. In a curable coating composition comprising: (1) a reactive
functional group-containing polymer, and (2) a curing agent having
functional groups reactive with the functional groups of (A), the
improvement comprising the inclusion in the coating composition of
(3) at least one reaction product of the following reactants: (1)
at least one polyoxyalkylene amine selected from the group
consisting of polyoxyalkylene monoamine, polyoxyalkylene diamine,
polyoxyalkylene triamine, and mixtures thereof, wherein the
polyoxyalkylene diamine comprises a compound having the following
structure (I): H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.-
sup.2--NH.sub.2 (I) where R.sup.1, R.sup.2, and R.sup.3 can be the
same or different and each independently represent a C.sub.2 to
C.sub.12 alkylene group, and (n+m) represents a value greater than
2, provided that when R.sup.1 and R.sup.3 are different (n+m)
represents a value greater than or equal to 2, and (2) at least one
cyclic carbonate. wherein a ratio of equivalents of amine (A) to
equivalents of cyclic carbonate (B) ranges from 1:0.5 to 1:1.5.
23. The coating composition of claim 22, wherein the reaction
product (3) is present in an amount sufficient to provide viscosity
stability of the composition such that the viscosity of the
composition increases not more than 50% upon storage for 16 hours
at a temperature ranging from 49.degree. C. to 71.degree. C.
24. The coating composition of claim 22, wherein the reaction
product (3) is present in an amount sufficient to provide viscosity
stability of the composition such that the viscosity of the
composition increases not more than 35% upon storage for 16 hours
at a temperature ranging from 49.degree. C. to 71.degree. C.
25. The coating composition of claim 22, wherein the reaction
product (3) is present in an amount sufficient to provide viscosity
stability of the composition such that the viscosity of the
composition increases not more than 20% upon storage for 16 hours
at a temperature ranging from 49.degree. C. to 71.degree. C.
26. The curable coating composition of claim 22, wherein the ratio
of equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.8 to 1:1.1.
27. The curable coating composition of claim 22, wherein the ratio
of equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.9 to 1:1.1.
28. The curable coating composition of claim 22, wherein R.sup.1,
R.sup.2, and R.sup.3 can be the same or different and each
independently represents a moiety selected from ethylene,
propylene, and butylene.
29. The curable coating composition of claim 22, wherein R.sup.1,
R.sup.2, and R.sup.3 can be the same or different and each
independently represents a moiety selected from ethylene and
propylene.
30. The curable coating composition of claim 22, wherein the cyclic
carbonate comprises a cyclic carbonate selected from the group
consisting of ethylene carbonate, propylene carbonate, butylene
carbonate, glycerine carbonate, and mixtures thereof.
31. The curable coating composition of claim 22, wherein the cyclic
carbonate is selected from at least one of ethylene carbonate,
propylene carbonate, and butylene carbonate.
32. The curable coating composition of claim 22, wherein the
reaction product (3) is present in an amount ranging from 5 to 25
weight percent resin solids, based on weight of total resin solids
present in the composition.
33. The curable coating composition of claim 22, wherein the
reaction product (3) is present in an amount ranging from 10 to 20
percent resin solids, based on weight of total resin solids present
in the composition.
34. The curable coating composition of claim 22 wherein the
composition comprises a water-based composition.
35. The curable coating composition of claim 22 wherein the
composition comprises solvent-based composition.
36. In a multilayer composite coating comprising a first coating
layer deposited over at least a portion of a substrate from a first
curable coating composition, and a second coating layer deposited
over at least a portion of the first coating layer, the second
coating layer formed from a second curable coating composition, the
first curable coating composition comprising: (1) a reactive
functional group-containing polymer; and (2) a curing agent having
functional groups reactive with the functional groups of (1), the
improvement comprising the inclusion in the first curable coating
composition of (3) at least one reactive product of the following
reactants: (A) at least one polyoxyalkylene amine selected from the
group consisting of polyoxyalkylene monoamine, polyoxyalkylene
diamine, polyoxyalkylene triamine, and mixtures thereof, wherein
the polyoxyalkylene diamine comprises a compound having the
following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.- sup.2--NH.sub.2
(I) where R.sup.1, R.sup.2 and R.sup.3 can be the same or different
and each independently represent a C.sub.2 to C.sub.12 alkylene
group, and (n+m) represents a value greater than 2, provided that
when R.sup.1 and R.sup.3 are different (n+m) represents a value
greater than or equal to 2; and (B) at least one cyclic carbonate,
wherein the ratio of equivalents of amine (A) to equivalents of
cyclic carbonate (B) ranges from 1:0.5 to 1.5.
37. The multilayer composite coating of claim 36, wherein the ratio
of equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.8 to 1.1.
38. The multilayer composite coating of claim 36, wherein wherein
the ratio of equivalents of amine (A) to equivalents of cyclic
carbonate (B) ranges from 1:0.9 to 1.1.
39. The multilayer composite coating of claim 36, wherein the
reaction product (3) is present in the first coating composition in
an amount sufficient to provide at least 50% interlayer adhesion
between the first and second coating layers as determined in
accordance with ASTM D3359-97.
40. The multilayer composite coating of claim 36, wherein the
reaction product (3) is present in the first coating composition in
an amount sufficient to provide at least 75% interlayer adhesion
between the first and second coating layers as determined in
accordance with ASTM D3359-97.
41. The multilayer composite coating of claim 36, wherein the
reaction product (3) is present in the first coating composition in
an amount sufficient to provide at least 80% interlayer adhesion
between the first and second coating layers as determined by ASTM
D3359-97.
42. The multilayer composite coating of claim 36, wherein the
reaction product (3) is present in the first coating composition in
an amount ranging from 1 to 50 weight percent resin solids, based
on the total weight of the resin solids present in the first
coating composition.
43. The multilayer composite coating of claim 36, wherein the
reaction product (3) is present in the first coating composition in
an amount ranging from 5 to 25 weight percent resin solids, based
on the total weight of the resin solids present in the first
coating composition.
44. The multilayer composite coating of claim 36, wherein the
cyclic carbonate comprises a cyclic carbonate selected from the
group consisting of ethylene carbonate, propylene carbonate,
butylene carbonate, glycerine carbonate, and mixtures thereof.
45. The multilayer composite coating of claim 36, wherein the
cyclic carbonate is selected from at least one of ethylene
carbonate, propylene carbonate, and butylene carbonate.
46. The multilayer composite coating of claim 36, wherein the first
coating layer comprises one or more pigments and the second coating
layer is substantially pigment free.
47. The multilayer composite coating of claim 36, wherein the first
coating layer comprises one or more pigments, and the second
coating layer comprises one or more pigments.
48. The multilayer composite coating of claim 36, wherein the first
coating layer is substantially pigment free and the second coating
layer comprises one or more pigments.
49. The multilayer composite coating of claim 22, wherein the first
coating layer is substantially pigment free and the second coating
layer comprises is substantially pigment free.
50. In a multilayer composite coating comprising a first coating
layer deposited over at least a portion of a substrate from a first
curable coating composition and a second coating layer deposited
over at least a portion of the first coating layer, the second
coating layer formed from a second curable coating composition, the
first curable coating composition comprising: (1) one or more
hydroxyl functional polymers selected from the group consisting of
a hydroxy-functional polyurethane polymer, a hydroxy-functional
acrylic polymer, and mixtures thereof, and (2) an aminoplast curing
agent, the improvement comprising the inclusion in the first
coating composition of (3) at least one reaction product of the
following reactants: (A) a polyisopropylether diamine, and (B) an
ethylene carbonate, wherein the ratio of equivalents of amine (A)
to equivalents of cyclic carbonate (B) ranges from 1:0.9 to 1:1.1;
wherein the reaction product (3) is present in the first curable
coating composition at a level ranging from 10 to 20 weight percent
resin solids, based on weight of total resin solids present in
first curable coating composition.
51. A coated substrate comprising a substrate and a cured coating
layer over at least a portion of the substrate, the cured layer
formed from the curable coating composition of claim 1.
52. A coated substrate comprising a substrate and a cured coating
layer over at least a portion of the substrate, the cured layer
formed from a curable coating composition comprising: (1) a
reactive functional group-containing polymer, and (2) a curing
agent having functional groups reactive with the functional groups
of (A), the improvement comprising the inclusion in the coating
composition of (3) at least one reaction product of the following
reactants: (A) at least one polyoxyalkylene amine selected from the
group consisting of polyoxyalkylene monoamine, polyoxyalkylene
diamine, polyoxyalkylene triamine, and mixtures thereof, wherein
the polyoxyalkylene diamine comprises a compound having the
following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.- sup.2--NH.sub.2
(I) where R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represent a C.sub.2 to C.sub.12
alkylene group, and (n+m) represents a value greater than 2,
provided that when R.sup.1 and R.sup.3 are different (n+m)
represents a value greater than or equal to 2; and (B) at least one
cyclic carbonate, wherein the ratio of equivalents of amine (A) to
equivalents of cyclic carbonate (B) ranges from 1:0.8 to 1:1.1,
characterized in that the reaction product (3) is present in the
coating composition in an amount sufficient to provide at least 50%
adhesion between the coating and substrate as determined in
accordance with ASTM-D3359-97.
53. The coated substrate of claim 52 wherein the reaction product
(3) is present in the coating composition in an amount sufficient
to provide at least 75% adhesion between the coating and substrate
as determined in accordance with ASTM-D3359-97.
54. The coated substrate of claim 52 wherein the reaction product
(3) is present in the coating composition in an amount sufficient
to provide at least 80% adhesion between the coating and substrate
as determined in accordance with ASTM-D3359-97.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to polyether carbamate
compounds formed from a polyoxyalkylene amine and a cyclic
carbonate and to their use in curable compositions, particularly in
curable coating compositions.
BACKGROUND OF THE INVENTION
[0002] Certain hydroxyalkyl, carbamates and polymers prepared
therefrom are known in the art. For example, U.S. Pat. Nos.
4,820,830 and 5,134,205 describe hydroxyalkyl carbamate compounds
prepared by reacting cyclic carbonates, for example ethylene
carbonate, propylene carbonate and butylene carbonate, with
selected aliphatic diamines. The hydroxyalkyl carbamates are
prepared without the use of any isocyanate intermediates and can be
used in coating compositions in conjunction with a crosslinking
agent such as a melamine-formaldehyde resin.
[0003] Also, beta-hydroxy urethane compounds (that is, urethane
compounds having a hydroxyl group in the beta position relative to
the carbamoxy group) are described in U.S. Pat. No. 4,435,559.
These beta-hydroxy urethane compounds are prepared by reacting an
isocyanate, for example, isophorone diisocyanate and
1,6-hexamethylene diisocyanate, with a 1,2-polyol, for example,
1,2-butanediol and 1,2-hexanediol, or a combination of a 1,2-polyol
and a conventional blocking agent, such as a monoalcohol. The
beta-hydroxy urethane compound is prepared under such conditions
that virtually no free isocyanate groups are remaining in the
resultant product. These beta-hydroxy urethane compounds are useful
in curable compositions as a crosslinking agent in conjunction with
other composition components, or in self-crosslinkable
compositions.
[0004] U.S. Pat. No. 5,340,889 describes liquid hydroxy-urethane
products having cyclocarbonate end groups prepared by reacting a
polyoxyalkylenediamine with a molar excess of a bis-carbonate of a
bis-glycidyl ether, for example the bis-glycidyl ether of neopentyl
glycol. The bis-carbonate material is reacted with the
polyoxyalkylenediamine in a molar ratio ranging from 5.0:1 to
2.0:1. This reaction ratio ensures that the resulting product has
cyclocarbonate end groups. The reaction is conducted at a
temperature ranging from ambient to 250.degree. C. and at a
pressure ranging from atmospheric up to 3000 psig.
[0005] Color-plus-clear coating systems involving the application
of a colored or pigmented base coat to a substrate followed by
application of a transparent or clear coat over at least a portion
of the base coat have become increasingly popular as original
finishes for a number of consumer products including for example,
automotive vehicles. The color-plus-clear coating systems have
outstanding appearance properties such as gloss and distinctness of
image, as well as excellent physical properties. Such
color-plus-clear coating systems have become can be used
advantageously in a variety of industrial applications including,
for example automotive, aerospace, flooring and packaging
applications.
[0006] Top coating systems, whether monocoats or the aforementioned
color-plus-clear systems, particularly those used for automotive
applications, are subject to various defects that can occur during
the assembly process as well as from numerous environmental
elements. On commercial automobile coating lines during application
of the coating system, certain portions of the line can experience
process problems. For example, the clear coat applicator might
malfunction, or curing ovens can widely vary in temperature from
the specification temperature. While the color coat typically is
"flash cured" at a temperature sufficient to drive off solvent but
not fully cure the coating, once the clear coating has been applied
the color-plus-clear coating system typically is given a full bake
(e.g., 250.degree. F. (121.degree. C.) for 30 minutes) to
simultaneously cure both the base coat and the top coat. In
instances where the clear coat application system is
malfunctioning, the auto body with the applied color coat can
continue through the clear coat applicator station and into the
clear coat curing oven, thereby fully curing the color coat. If
this occurs, some automobile manufacturers elect to reapply the
color coat over the fully cured color coat prior to application of
the clear coat. In such situations, the fully cured color coat can
have poor intercoat adhesion with the subsequently applied color
coat, even though the compositions may be the same.
[0007] Moreover, as discussed previously, during the assembly
process, the applied color-plus-clear coating can include surface
defects in the coating surface which require repair. Some
automobile manufacturers elect to remove the defect and recoat the
repair area with the same color-plus-clear system. In such
instances, the color coating composition must be applied directly
to the surface of a fully cured clear coat, followed by application
of the clear coating composition over the color coating
composition. It is known, however, that some clear coats when cured
have poor intercoat adhesion with the subsequently applied repair
color coat. This is believed to result due to the difference in
surface energy of the cured clear coat and the subsequently applied
repair color coating composition.
[0008] In recent years the trend in the automotive industry has
been to reduce atmospheric pollution caused by the volatile
solvents which are emitted during the painting process. One
approach to emissions control has been the use of waterborne
coating compositions as the pigmented or color coat in the
color-plus-clear coating system.
[0009] U.S. Pat. Nos. 5,071,904 and 5,510,148 describe waterborne
coating compositions useful for forming a base coat in
color-plus-clear coating systems. The compositions comprise a
polymeric film-forming resin comprising an aqueous dispersion of
polymeric microparticles. The polymeric microparticles contain a
substantially hydrophobic polymer which is essentially free of
repeating acrylic or vinyl units in the backbone and is adapted to
be chemically bound into the cured coating compositions. The
remainder of the microparticle comprises an acrylic monomer or
mixture of monomers. The hydrophobic polymer and the acrylic
monomer(s) are particularized by high stress techniques followed by
polymerization of the monomers to produce the polymeric
microparticles which are stably dispersed in aqueous media.
[0010] Some waterborne coating compositions, however, are not
without attendant disadvantages. For example, some waterborne
coatings can have a narrow application window because it can be
difficult to obtain smooth cured coatings, free of popping
(described below), over a wide range of relative humidities. For
example, in some instances, where the coating composition is
applied in an environment having high relative humidity, water
cannot readily evaporate from the applied film during the flash or
dehydration period prior to curing at elevated temperatures.
[0011] Also, it has been noted that some waterborne coating
compositions can increase in viscosity upon storage. Such a
viscosity increase can occur for a number of reasons, for example,
hydrogen bonding between various components and/or instability of
rheology control additives such as associative thickeners. Such
poor storage stability can necessitate the addition of water to
adjust the application viscosity of the composition. This
additional water decreases application resin solids of the
composition, and can result in surface defects commonly referred to
as "popping" which occur as water (and solvent if present)
volatilizes through the coating surface upon curing.
[0012] In view of the foregoing it is desirable to provide
waterborne coating compositions which have improved storage
stability, excellent resistance to mottling and popping, good
appearance properties, and acceptable adhesion properties.
SUMMARY OF THE INVENTION
[0013] In one embedment, the present invention is directed to a
reaction product comprising polyether carbamate groups, the
reaction product formed from (A) at least one polyoxyalkylene
amine, and (B) at least one cyclic carbonate, wherein a ratio of
equivalents of amine (A) to equivalents of cyclic carbonate (B)
ranges from 1:0.5 to 1:1.5. The at least one polyoxyalkylene amine
selected from the group consisting of polyoxyalkylene monoamine,
polyoxyalkylene diamine, polyoxyalkylene triamine, and mixtures
thereof, wherein the polyoxyalkylene diamine comprises a compound
having the following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.sup.2--NH.sub.2
(I)
[0014] where R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represent a C.sub.2 to C.sub.12
alkylene group, and (n+m) represents a value greater than 2,
provided that when R.sup.1 and R.sup.3 are different (n+m)
represents a value greater than or equal to 2.
[0015] In a further embodiment, the present invention is directed
to a reaction product comprising polyether carbamate groups, the
reaction product formed from (A) at least one polyoxyalkylene
amine, and (B) at least one cyclic carbonate selected from
propylene carbonate, butylene carbonate, glycerine carbonate, and
mixtures thereof, wherein a ratio of equivalents of amine (A) to
equivalents of cyclic carbonate (B) ranges from 1:0.5 to 1:1.5.
[0016] In another embodiment, the present invention provides a
reaction product prepared by the following steps: (a) admixing at
least one cyclic carbonate and at least one polyetheramine selected
from the group consisting of polyoxyalkylene monoamine,
polyoxyalkylene diamine, polyoxyalkylene triamine, and mixtures
thereof, wherein the polyoxyalkylene diamine comprises a compound
having the structure (I) where R.sup.1, R.sup.2, and R.sup.3, and
and (n+m) are as described above for that structure; optionally, in
the presence of an alkoxide catalyst, to form a reaction mixture
such that the ratio of equivalents of amine to equivalents of
cyclic carbonate is 1:0.5 to 1:1.5; and (b) maintaining the
reaction mixture of step (a) at a temperature ranging from ambient
temperature to 150.degree. C. at atmospheric pressure for a period
of time sufficient to drive the reaction to 80 percent of
theoretical completion.
[0017] In a further embodiment, the present invention is directed
to an improved curable coating composition comprising (1) a
reactive functional group-containing polymer, and (2) a curing
agent having functional groups reactive with the functional groups
of (1) The improvement comprises the inclusion in the coating
composition of (3) the at least one reaction product of (A) at
least one polyoxyalkylene amine selected from the group consisting
of polyoxyalkylene monoamine, polyoxyalkylene diamine,
polyoxyalkylene triamine, and mixtures thereof, wherein the
polyoxyalkylene diamine comprises a compound having the structure
(!) as described above, and (B) at least one cyclic carbonate,
wherein a ratio of equivalents of amine (A) to equivalents of
cyclic carbonate (B) ranges from 1:0.5 to 1:1.5.
[0018] The present invention also provides an improved multilayer
composite coating comprising a first coating layer deposited over
at least a portion of a substrate from a first curable coating
composition, and a second coating layer deposited over at least a
portion of the first coating layer, the second coating layer formed
from a second curable coating composition. The first curable
coating composition comprises (1) a reactive functional
group-containing polymer, and (2) a curing agent having functional
groups reactive with the functional groups of (1). The improvement
comprises the inclusion in the first curable coating composition of
the at least one reaction product (3) as described above with
respect to the curable coating composition of the present
invention.
[0019] Additionally, the present invention provides a substrate
comprising a substrate and a cured coating layer over at least a
portion of the substrate formed from any of the previously
described curable coating compositions.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Other than in the operating examples, or where otherwise
indicated, all numbers expressing quantities of ingredients,
reaction conditions and so forth used in the specification and
claims are to be understood as being modified in all instances by
the term "about." Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the following specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained by the present
invention. 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.
[0021] 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 values, however,
inherently contain certain errors necessarily resulting from the
standard deviation found in their respective testing
measurements.
[0022] 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.
[0023] As mentioned above, in one embodiment, the present invention
is directed to a reaction product comprising polyether carbamate
groups. The reaction product can be formed from (A) at least one
polyoxyalkylene amine, and (B) at least one cyclic carbonate.
[0024] The polyoxyalkylene amine (A) can include polyoxyalkylene
monoamines, and polyoxyalkylene polyamines, for example,
polyoxyalkylene diamine and polyoxyalkylene triamine. In one
embodiment of the present invention, the polyoxyalkylene amine is
selected from the group consisting of polyoxyalkylene monoamine,
polyoxyalkylene diamine, polyoxyalkylene triamine, and mixtures
thereof. As used herein, by "polyoxyalkylene polyamine" is meant a
polyamine containing both oxyalkylene groups and at least two amine
groups, typically primary amine groups, per molecule.
[0025] In one embodiment of the present invention, the
polyoxyalkylene amine comprises a polyoxyalkylene diamine
represented by the following structure (I):
H.sub.2N[R.sup.1--O].sub.n[R.sup.3--O].sub.m--R.sup.2-NH.sub.2
(I)
[0026] wherein R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represents a C.sub.2 to C.sub.12,
typically a C.sub.2 to C.sub.4, alkylene groups and (n+m)
represents a value greater than 2 and up to 200, provided that when
R.sup.1 and R.sup.3 are different, (n+m) represents a value equal
to or greater than 2 and up to 200. In one embodiment, (n+m)
represents a value ranging from 3 to 50, usually from 5 to 35 and
typically from 5 to 12.
[0027] By "alkylene" is meant acyclic or cyclic alkylene groups
having a carbon chain length of from C.sub.2 to C.sub.25, typically
C.sub.2 to C.sub.12 which may be substituted or unsubstituted, and
which may include substituents, for example, lower alkyl radicals
having from 1 to 12 carbon atoms. In a particular embodiment of the
present invention, R.sup.1, R.sup.2, and R.sup.3 can be the same or
different and each independently represents an alkylene group
selected from ethylene, propylene, butylene, and mixtures thereof.
For purposes of the present invention, "propylene" groups are
intended to include both n-propylene and isopropylene groups; and,
likewise, "butylene" groups are intended to include both
n-butylene, isobutylene, and t-butylene groups.
[0028] Moreover, the structure (I) above is diagrammatic only and
is not intended to imply that the parenthetical portions thereof
are necessarily blocks, although blocks may be used where desired.
For example, the polymer represented by the structure (I) may be a
random copolymer of --[R.sup.1--O]-- and --[R.sup.3--O]--, a
homopolymer of either --[R.sup.1--O]-- or --[R.sup.3--O]--, or a
block copolymer of --[R.sup.1--O]-- and --[R.sup.3--O]--.
[0029] Specific non-limiting examples of polyoxyalkylene amines
which are suitable for use in forming the polyether carbamate
group-containing reaction products of the present invention include
polyoxyalkylene polyamines, such as the polyoxypropylene diamines
commercially available under the tradenames JEFFAMINE.RTM. D-2000
and JEFFAMINE.RTM. D-400, commercially available from Huntsman
Corporation of Houston, Tex. A variety of other suitable
polyoxyalkylene amines are described in detail in U.S. Pat. No.
3,236,895, column 2, lines 40 to 72; methods of preparation of the
polyoxyalkylene amines are illustrated in the patent in Examples 4,
5, 6 and 8-12 in columns 4 to 9 thereof, the aforementioned
portions of U.S. Pat. No. 3,236,895 hereby being incorporated by
reference herein.
[0030] Mixed polyoxyalkylene polyamines, that is, those in which
the oxyalkylene group can be selected from more than one moiety,
also can be used advantageously. Suitable examples of such mixed
polyoxyalkylene polyamines include polyoxyethylene-polyoxypropylene
polyamines.
[0031] Besides the polyoxyalkylene amines mentioned above,
derivatives of polyoxyalkylene polyols can also be used. Examples
of suitable derivatives include aminoalkylene derivatives which are
prepared by reacting polyoxyalkylene polyols as are well known in
the art with acrylonitrile followed by hydrogenation of the
reaction product in an art recognized manner. Exemplary of such
derivatives is polytetramethylene glycol
bis(3-aminopropyl(ether)).
[0032] In one embodiment of the present invention, R.sup.1,
R.sup.2, and R.sup.3 can be the same or different and each
independently represents an alkylene group selected from ethylene
and isopropylene, and (n+m) represents a value greater than 2,
provided that when R.sup.1 and R.sup.3 are different, (n+m) is
equal to or greater than 2. Typically, R.sup.1, R.sup.2, and
R.sup.3, which can be the same or different, each independently
represents an alkylene group selected from ethylene and
isopropylene, and the value represented by (n+m) satisfies the
condition 5.ltoreq.(n+m).ltoreq.6.
[0033] In an alternative embodiment of the present invention, the
polyoxyalkylene amine comprises a polyoxyalkylene triamine
represented by the following structures (II) or (III): 1 2
[0034] wherein R.sup.1, R.sup.2, and R.sup.3 independently can be
the same or different and each independently represents a moiety
selected from ethylene, propylene, and butylene; and x, y, and z
independently can be the same or different, and each independently
represents a value greater than or equal to 1.
[0035] The cyclic carbonate (B) used to form the polyether
carbamate group-containing reaction product of the present
invention can be selected from any of a variety of cyclic
carbonates well known in the art. Suitable non-limiting examples
include cyclic carbonates selected from the group consisting of
ethylene carbonate, propylene carbonate, butylene carbonate,
glycerine carbonate, a di(cyclic carbonate) compound represented by
the following structure (IV), and mixtures thereof: 3
[0036] wherein R and R' may independently represent H, CH.sub.3, or
CH.sub.2OH, and A represents an organic divalent group. The organic
divalent group can represent, for example, a cyclic or acyclic,
substituted or unsubstituted alkylene group, oxyalkylene group,
aralkylene or alkylene aryl group. By "oxyalkylene" is meant an
alkylene group containing one or more other oxygen atoms. By
"aralkylene is meant a divalent aromatic group, which may be
ring-substituted. By "alkylene aryl" is meant any acyclic alkylene
group containing at least one aryl group, for example phenyl.
[0037] Typically, the cyclic carbonate (B) is selected from at
least one of ethylene carbonate, propylene carbonate, and butylene
carbonate.
[0038] The polyether carbamate group-containing reaction product of
the present invention typically is prepared by admixing the
polyoxyalkylene amine (A) and the cyclic carbonate (B) as described
above, optionally, in the presence of an alkoxide catalyst, for
example potassium tertiary butoxide to form a reaction mixture such
that the ratio of equivalents of amine of (A) to equivalents of
carbonate of (B) ranges from 1:0.5 to 1:1.5, usually from 1:0.8 to
1:1.1, and typically from 1:0.9 to 1:1.1; and heating the reaction
mixture to a temperature ranging from ambient temperature to
150.degree. C., can be from 50.degree. C. to 150.degree. C.,
typically from 90.degree. C. to 140.degree. C. at atmospheric
pressure for a period of time sufficient to drive the reaction to
80 percent, typically 90 percent, of theoretical completion. It
should be understood that lower temperature can be used if the
reaction is conducted at higher pressured. By "theoretical
completion" is meant complete consumption of the reactant which is
present in the least amount on an equivalence basis.
[0039] Also, it should be understood that the polyether carbamate
group-containing reaction product can contain the reaction product
of the polyoxyalkylene amine (A) and the cyclic carbonate (B), as
well as any residual unreacted polyoxyalkylene amine (A), any
residual unreacted cyclic carbonate (B), and any rearrangement
products of the starting materials (A) and (B).
[0040] In any event, the reactants (A) and (B) are reacted in
amounts and under conditions such that at least a portion of, and
typically, substantially all, of the resulting reaction product is
hydroxy-terminated.
[0041] As previously discussed, the present invention also is
directed to an improved curable composition, preferably a curable
coating composition, comprising (1) a reactive functional
group-containing polymer, and (2) a curing agent having functional
groups reactive with the functional groups of (1). The improvement
comprises the inclusion in the coating composition of (3) at least
one polyether carbamate group-containing reaction product as
described in detail above.
[0042] The reaction product containing polyether carbamate groups
(3) can be present in the curable coating composition of the
present invention in an amount of at least 1 percent by weight,
often at least 5 percent by weight and typically at least 10
percent by weight resin solids based on total weight of resin
solids present in the composition. Also, the reaction products (3)
can be present in the curable coating composition of the present
invention in an amount less than or equal to 50 percent by weight,
often 25 percent by weight, and typically 20 percent by weight
resin solids, based on total weight of resin solids present in the
curable composition. The amount of the reaction product (3) present
in the curable coating composition of the present invention can
range between any combination of these values inclusive of the
recited values.
[0043] As used herein, the term "cure" as used in connection with a
composition, e.g., "a curable composition," shall mean that at
least a portion of the curable or crosslinkable components which
form the composition are capable of forming an at least partially
crosslinked network. In certain embodiments of the present
invention, the crosslink density of the crosslinkable components,
i.e., the degree of crosslinking, ranges from 5% to 100% of
complete crosslinking. In other embodiments, the crosslink density
ranges from 35% to 85% of full crosslinking. In other embodiments,
the crosslink density ranges from 50% to 85% of full crosslinking.
One skilled in the art will understand that the presence and degree
of crosslinking, i.e., the crosslink density, can be determined by
a variety of methods, such as dynamic mechanical thermal analysis
(DMTA) using a TA Instruments DMA 2980 DMTA analyzer conducted
under nitrogen such as is described above. This method determines
the glass transition temperature and crosslink density of free
films of coatings or polymers. These physical properties of a cured
material are related to the structure of the crosslinked
network.
[0044] Also, as used herein, the term "polymer" is intended to
included oligomers as well as polymers, and homopolymers, that is
polymers formed from one polymerizable species, as well as
heteropolymers, that is polymers formed from at least two different
polymerizable species.
[0045] The reactive functional group-containing polymer (1) can be
any of a variety of polymers well known in the art. For example,
the polymer (1) can be selected from at least one of polyether
polymers, polyester polymers, acrylic polymers, silicon-based
polymers, polyepoxide polymers, and polyurethane polymers. Mixtures
of any of the foregoing polymers can be used.
[0046] In a particular embodiment of the present invention, the
polymer (1) can comprise at least one reactive functional group
selected from a hydroxyl group, a carboxyl group, an isocyanate
group, a blocked isocyanate group, a primary amine group, a
secondary amine group, an amide group, a carbamate group, a urea
group, a urethane group, a vinyl group, an unsaturated ester group,
a maleimide group, a fumarate group, an anhydride group, a hydroxy
alkylamide group, and an epoxy group. Combinations of any of the
foregoing reactive functional groups can comprise the polymer
(1).
[0047] In another embodiment of the present invention, the
film-forming polymer (1) comprises at least one reactive functional
group selected from a hydroxyl group, a carbamate group, an epoxy
group, an isocyanate group, and a carboxyl group. In another
embodiment, the polymer (1) comprises at least one reactive
functional group selected from a hydroxyl group, and a carboxyl
group.
[0048] Suitable hydroxyl group-containing polymers can include
acrylic polyols, polyester polyols, polyurethane polyols, polyether
polyols, and mixtures thereof. In a particular embodiment of the
present invention, the film-forming polymer is an acrylic polyol
having a hydroxyl equivalent weight ranging from 50 to 4000 grams
per solid equivalent, typically 50 to 500 grams per solid
equivalent.
[0049] Suitable hydroxyl group and/or carboxyl group-containing
acrylic polymers can be prepared from polymerizable ethylenically
unsaturated monomers and are typically copolymers of (meth)acrylic
acid and/or hydroxylalkyl esters of (meth)acrylic acid with one or
more other polymerizable ethylenically unsaturated monomers such as
alkyl esters of (meth)acrylic acid including methyl (meth)acrylate,
ethyl (meth)acrylate, butyl (meth)acrylate and 2-ethyl
hexylacrylate, and vinyl aromatic compounds such as styrene,
alpha-methyl styrene, and vinyl toluene. As used herein,
"(meth)acrylate" and like terms is intended to include both
acrylates (derived from acrylic acid) and methacrylates (derived
from methacrylic acid).
[0050] The acrylic polymer also can be prepared from ethylenically
unsaturated, beta-hydroxy ester functional monomers. Such monomers
can be derived from the reaction of an ethylenically unsaturated
acid functional monomer, such as monocarboxylic acids, for example,
acrylic acid, and an epoxy compound which does not participate in
the free radical initiated polymerization with the unsaturated acid
monomer. Examples of such epoxy compounds include glycidyl ethers
and esters. Suitable glycidyl ethers include glycidyl ethers of
alcohols and phenols such as butyl glycidyl ether, octyl glycidyl
ether, phenyl glycidyl ether and the like. Suitable glycidyl esters
include those which are commercially available from Shell Chemical
Company under the tradename CARDURA E; and from Exxon Chemical
Company under the tradename GLYDEXX-10. Alternatively, the
beta-hydroxy ester functional monomers can be prepared from an
ethylenically unsaturated, epoxy functional monomer, for example
glycidyl (meth)acrylate and allyl glycidyl ether, and a saturated
carboxylic acid, such as a saturated monocarboxylic acid, for
example isostearic acid.
[0051] Epoxy functional groups can be incorporated into the polymer
prepared from polymerizable ethylenically unsaturated monomers by
copolymerizing oxirane group-containing monomers, for example
glycidyl (meth)acrylate and allyl glycidyl ether, with other
polymerizable ethylenically unsaturated monomers, such as those
discussed above. Preparation of such epoxy functional acrylic
polymers is described in detail in U.S. Pat. No. 4,001,156 at
columns 3 to 6, incorporated herein by reference.
[0052] Carbamate functional groups can be incorporated into the
polymer prepared from polymerizable ethylenically unsaturated
monomers by copolymerizing, for example, the above-described
ethylenically unsaturated monomers with a carbamate functional
vinyl monomer such as a carbamate functional alkyl ester of
methacrylic acid. Useful carbamate functional alkyl esters can be
prepared by reacting, for example, a hydroxyalkyl carbamate, such
as the reaction product of ammonia and ethylene carbonate or
propylene carbonate, with methacrylic anhydride. Other useful
carbamate functional vinyl monomers include, for instance, the
reaction product of hydroxyethyl methacrylate, isophorone
diisocyanate, and hydroxypropyl carbamate; or the reaction product
of hydroxypropyl methacrylate, isophorone diisocyanate, and
methanol. Still other carbamate functional vinyl monomers may be
used, such as the reaction product of isocyanic acid (HNCO) with a
hydroxyl functional acrylic or methacrylic monomer such as
hydroxyethyl acrylate, and those described in U.S. Pat. No.
3,479,328, incorporated herein by reference. Carbamate functional
groups can also be incorporated into the acrylic polymer by
reacting a hydroxyl functional acrylic polymer with a low molecular
weight alkyl carbamate such as methyl carbamate. Pendant carbamate
groups can also be incorporated into the acrylic polymer by a
"transcarbamoylation" reaction in which a hydroxyl functional
acrylic polymer is reacted with a low molecular weight carbamate
derived from an alcohol or a glycol ether. The carbamate groups
exchange with the hydroxyl groups yielding the carbamate functional
acrylic polymer and the original alcohol or glycol ether. Also,
hydroxyl functional acrylic polymers can be reacted with isocyanic
acid to provide pendent carbamate groups. Likewise, hydroxyl
functional acrylic polymers can be reacted with urea to provide
pendent carbamate groups.
[0053] The acrylic polymers can be prepared by solution
polymerization techniques, which are well-known to those skilled in
the art, in the presence of suitable catalysts such as organic
peroxides or azo compounds, for example, benzoyl peroxide or
N,N-azobis(isobutylronitrile)- . The polymerization can be carried
out in an organic solution in which the monomers are soluble by
techniques conventional in the art. Alternatively, these polymers
can be prepared by aqueous emulsion or dispersion polymerization
techniques which are well-known in the art. The ratio of reactants
and reaction conditions are selected to result in an acrylic
polymer with the desired pendent functionality.
[0054] Polyester polymers are also useful in the coating
compositions of the invention as the film-forming polymer. Useful
polyester polymers typically include the condensation products of
polyhydric alcohols and polycarboxylic acids. Suitable polyhydric
alcohols can include ethylene glycol, neopentyl glycol, trimethylol
propane, and pentaerythritol. Suitable polycarboxylic acids can
include adipic acid, 1,4-cyclohexyl dicarboxylic acid, and
hexahydrophthalic acid. Besides the polycarboxylic acids mentioned
above, functional equivalents of the acids such as anhydrides where
they exist or lower alkyl esters of the acids such as the methyl
esters can be used. Also, small amounts of monocarboxylic acids
such as stearic acid can be used. The ratio of reactants and
reaction conditions are selected to result in a polyester polymer
with the desired pendent functionality, i.e., carboxyl or hydroxyl
functionality.
[0055] For example, hydroxyl group-containing polyesters can be
prepared by reacting an anhydride of a dicarboxylic acid such as
hexahydrophthalic anhydride with a diol such as neopentyl glycol in
a 1:2 molar ratio. Where it is desired to enhance air-drying,
suitable drying oil fafty acids may be used and include those
derived from linseed oil, soya bean oil, tall oil, dehydrated
castor oil, or tung oil.
[0056] Carbamate functional polyesters can be prepared by first
forming a hydroxyalkyl carbamate that can be reacted with the
polyacids and polyols used in forming the polyester. Alternatively,
terminal carbamate functional groups can be incorporated into the
polyester by reacting isocyanic acid with a hydroxy functional
polyester. Also, carbamate functionality can be incorporated into
the polyester by reacting a hydroxyl polyester with a urea.
Additionally, carbamate groups can be incorporated into the
polyester by a transcarbamoylation reaction. Preparation of
suitable carbamate functional group-containing polyesters are those
described in U.S. Pat. No. 5,593,733 at column 2, line 40 to column
4, line 9, incorporated herein by reference.
[0057] Polyurethane polymers containing terminal isocyanate or
hydroxyl groups also can be used as the polymer (1) in the curable
compositions of the present invention. The polyurethane polyols or
NCO-terminated polyurethanes which can be used are those prepared
by reacting polyols including polymeric polyols with
polyisocyanates. Polyureas containing terminal isocyanate or
primary and/or secondary amine groups which also can be used are
those prepared by reacting polyamines including polymeric
polyamines with polyisocyanates. The hydroxyl/isocyanate or
amine/isocyanate equivalent ratio is adjusted and reaction
conditions are selected to obtain the desired terminal groups.
Examples of suitable polyisocyanates include those described in
U.S. Pat. No. 4,046,729 at column 5, line 26 to column 6, line 28,
incorporated herein by reference. Examples of suitable polyols
include those described in U.S. Pat. No. 4,046,729 at column 7,
line 52 to column 10, line 35, incorporated herein by reference.
Examples of suitable polyamines include those described in U.S.
Pat. No. 4,046,729 at column 6, line 61 to column 7, line 32 and in
U.S. Pat. No. 3,799,854 at column 3, lines 13 to 50, both
incorporated herein by reference.
[0058] Carbamate functional groups can be introduced into the
polyurethane polymers by reacting a polyisocyanate with a polyester
having hydroxyl functionality and containing pendent carbamate
groups. Alternatively, the polyurethane can be prepared by reacting
a polyisocyanate with a polyester polyol and a hydroxyalkyl
carbamate or isocyanic acid as separate reactants.
[0059] Examples of suitable polyisocyanates are aromatic
isocyanates, such as 4,4'-diphenylmethane diisocyanate,
1,3-phenylene diisocyanate and toluene diisocyanate, and aliphatic
polyisocyanates, such as 1,4-tetramethylene diisocyanate and
1,6-hexamethylene diisocyanate. Cycloaliphatic diisocyanates, such
as 1,4-cyclohexyl diisocyanate and isophorone diisocyanate also can
be employed.
[0060] Examples of suitable polyether polyols include polyalkylene
ether polyols such as those having the following structural
formulas: 4
[0061] wherein the substituent R is hydrogen or a lower alkyl group
containing from 1 to 5 carbon atoms including mixed substituents,
and n has a value typically ranging from 2 to 6 and m has a value
ranging from 8 to 100 or higher.
[0062] Exemplary polyalkylene ether polyols include
poly(oxytetramethylene) glycols, poly(oxytetraethylene) glycols,
poly(oxy-1,2-propylene) glycols, and poly(oxy-1,2-butylene)
glycols.
[0063] Also useful are polyether polyols formed from oxyalkylation
of various polyols, for example, glycols such as ethylene glycol,
1,6-hexanediol, Bisphenol A, and the like, or other higher polyols
such as trimethylolpropane, pentaerythritol, and the like. Polyols
of higher functionality which can be utilized as indicated can be
made, for instance, by oxyalkylation of compounds such as sucrose
or sorbitol. One commonly utilized oxyalkylation method is reaction
of a polyol with an alkylene oxide, for example, propylene or
ethylene oxide, in the presence of an acidic or basic catalyst.
Specific examples of polyethers include those sold under the names
TERATHANE.RTM. and TERACOL.RTM., available from E.I. DuPont de
Nemours and Company.
[0064] Hydroxyl functional group-containing polymers typically are
employed.
[0065] Polyepoxides such as those described below with reference to
the curing agent (B), can also be used.
[0066] The polymer (1) having reactive functional groups can be
present in the curable compositions in an amount of at least 2
percent by weight, usually at least 5 percent by weight, and
typically at least 10 percent by weight resin solids based on
weight of total resin solids in the coating composition. Also, the
polymer (1) having reactive functional groups can be present in the
thermosetting compositions of the invention in an amount less than
95 percent by weight, usually less than 90 percent by weight, and
typically less than 85 percent by weight based on weight of total
resin solids in the coating composition. The amount of the polymer
(1) having reactive functional groups present in the compositions
of the present invention can range between any combination of these
values inclusive of the recited values.
[0067] As aforementioned, in addition to the functional
group-containing film-forming polymer (1) and the polyether
carbamate group-containing reaction product (3), the curable
composition of the present invention further comprises at least one
curing agent (2) having functional groups reactive with the
functional groups of the polymer (1).
[0068] Dependent upon the reactive functional groups of the polymer
(1), the curing agent (2) can be selected from an aminoplast resin,
a polyisocyanate, a blocked isocyanate, a polyepoxide, a polyacid,
an anhydride, an amine, a polyol, and mixtures of any of the
foregoing. In one embodiment, the at least one curing agent (2) is
selected from an aminoplast resin and a polyisocyanate.
[0069] In another embodiment, the present invention is directed to
any composition as previously described wherein the curing agent
comprises an aminoplast resin. Aminoplast resins, which can
comprise phenoplasts, as curing agents for hydroxyl, carboxylic
acid, and carbamate functional group-containing materials are well
known in the art. Suitable aminoplast resins, such as, for example,
those discussed above, are known to those of ordinary skill in the
art. Aminoplasts can be obtained from the condensation reaction of
formaldehyde with an amine or amide. Nonlimiting examples of amines
or amides include melamine, urea, or benzoguanamine. Condensates
with other amines or amides can be used; for example, aldehyde
condensates of glycoluril, which give a high melting crystalline
product useful in powder coatings. While the aldehyde used is most
often formaldehyde, other aldehydes such as acetaldehyde,
crotonaldehyde, and benzaldehyde can be used.
[0070] The aminoplast resin contains imino and methylol groups and
in certain instances at least a portion of the methylol groups are
etherified with an alcohol to modify the cure response. Any
monohydric alcohol can be employed for this purpose including
methanol, ethanol, n-butyl alcohol, isobutanol, and hexanol.
[0071] Nonlimiting examples of aminoplasts include melamine-,
urea-, or benzoguanamine-formaldehyde condensates, in certain
instances monomeric and at least partially etherified with one or
more alcohols containing from one to four carbon atoms. Nonlimiting
examples of suitable aminoplast resins are commercially available,
for example, from Cytec Industries, Inc. under the trademark
CYMEL.RTM. and from Solutia, Inc. under the trademark
RESIMENE.RTM..
[0072] In another embodiment of the present invention, the curing
agent comprises an aminoplast resin which, when added to the other
components that form the thermosetting composition, is generally
present in an amount ranging from 2 weight percent to 65 weight
percent, can be present in an amount ranging from 5 weight percent
to 50 weight percent, and typically is present in an amount ranging
from 5 weight percent to 40 weight percent based on total weight of
resin solids present in the composition.
[0073] In yet another embodiment of the present invention the
curing agent (2) comprises a polyisocyanate curing agent. As used
herein, the term "polyisocyanate" is intended to include blocked
(or capped) isocyanates as well as unblocked (poly)isocyanates. The
polyisocyanate can be an aliphatic or an aromatic polyisocyanate,
or a mixture of the two. Diisocyanates can be used, although higher
polyisocyanates such as isocyanurates of diisocyanates are often
used. Higher polyisocyanates also can be used in combination with
diisocyanates. Isocyanate prepolymers, for example, reaction
products of polyisocyanates with polyols also can be used. Mixtures
of polyisocyanate curing agents can be used.
[0074] If the polyisocyanate is blocked or capped, any suitable
aliphatic, cycloaliphatic, or aromatic alkyl monoalcohol known to
those skilled in the art can be used as a capping agent for the
polyisocyanate. Other suitable capping agents include oximes and
lactams. When used, the polyisocyanate curing agent is typically
present, when added to the other components which form the coating
composition, in an amount ranging from 5 to 65 weight percent, can
be present in an amount ranging from 10 to 45 weight percent, and
often are present in an amount ranging from 15 to 40 percent by
weight based on the total weight of resin solids present in the
composition.
[0075] Other useful curing agents comprise other blocked isocyanate
compounds such as, for example, the tricarbamoyl triazine compounds
described in detail in U.S. Pat. No. 5,084,541, which is
incorporated by reference herein. When used, the blocked
polyisocyante curing agent can be present, when added to the other
components in the composition, in an amount ranging up to 20 weight
percent, and can be present in an amount ranging from 1 to 20
weight percent, based on the total weight of resin solids present
in the composition.
[0076] In one embodiment of the present invention, the curing agent
comprises both an aminoplast resin and a polyisocyanate.
[0077] Anhydrides as curing agents for hydroxyl functional
group-containing materials also are well known in the art and can
be used in the present invention. Nonlimiting examples of
anhydrides suitable for use as curing agents in the compositions of
the invention include those having at least two carboxylic acid
anhydride groups per molecule which are derived from a mixture of
monomers comprising an ethylenically unsaturated carboxylic acid
anhydride and at least one vinyl co-monomer, for example, styrene,
alpha-methyl styrene, vinyl toluene, and the like. Nonlimiting
examples of suitable ethylenically unsaturated carboxylic acid
anhydrides include maleic anhydride, citraconic anhydride, and
itaconic anhydride. Alternatively, the anhydride can be an
anhydride adduct of a diene polymer such as maleinized
polybutadiene or a maleinized copolymer of butadiene, for example,
a butadiene/styrene copolymer. These and other suitable anhydride
curing agents are described in U.S. Pat. No. 4,798,746 at column
10, lines 16-50; and in U.S. Pat. No. 4,732,790 at column 3, lines
41-57, both of which are incorporated herein by reference.
[0078] Polyepoxides as curing agents for carboxylic acid functional
group-containing materials are well known in the art. Nonlimiting
examples of polyepoxides suitable for use in the compositions of
the present invention comprise polyglycidyl esters (such as
acrylics from glycidyl methacrylate), polyglycidyl ethers of
polyhydric phenols and of aliphatic alcohols, which can be prepared
by etherification of the polyhydric phenol, or aliphatic alcohol
with an epihalohydrin such as epichlorohydrin in the presence of
alkali. These and other suitable polyepoxides are described in U.S.
Pat. No. 4,681,811 at column 5, lines 33 to 58, which is
incorporated herein by reference.
[0079] Suitable curing agents for epoxy functional group-containing
materials comprise polyacid curing agents, such as the acid
group-containing acrylic polymers prepared from an ethylenically
unsaturated monomer containing at least one carboxylic acid group
and at least one ethylenically unsaturated monomer which is free
from carboxylic acid groups. Such acid functional acrylic polymers
can have an acid number ranging from 30 to 150. Acid functional
group-containing polyesters can be used as well. The
above-described polyacid curing agents are described in further
detail in U.S. Pat. No. 4,681,811 at column 6, line 45 to column 9,
line 54, which is incorporated herein by reference.
[0080] Also well known in the art as curing agents for isocyanate
functional group-containing materials are polyols, that is,
materials having two or more hydroxyl groups per molecule,
different from component (1) when component (1) is a polyol.
Nonlimiting examples of such materials suitable for use in the
compositions of the invention include polyalkylene ether polyols,
including thio ethers; polyester polyols, including polyhydroxy
polyesteramides; and hydroxyl-containing polycaprolactones and
hydroxy-containing acrylic copolymers. Also useful are polyether
polyols formed from the oxyalkylation of various polyols, for
example, glycols such as ethylene glycol, 1,6-hexanediol, Bisphenol
A and the like, or higher polyols such as trimethylolpropane,
pentaerythritol, and the like. Polyester polyols also can be used.
These and other suitable polyol curing agents are described in U.S.
Pat. No. 4,046,729 at column 7, line 52 to column 8, line 9; column
8, line 29 to column 9, line 66; and U.S. Pat. No. 3,919,315 at
column 2, line 64 to column 3, line 33, both of which are
incorporated herein by reference.
[0081] Polyamines also can be used as curing agents for isocyanate
functional group-containing materials. Nonlimiting examples of
suitable polyamine curing agents include primary or secondary
diamines or polyamines in which the radicals attached to the
nitrogen atoms can be saturated or unsaturated, aliphatic,
alicyclic, aromatic, aromatic-substituted-aliphatic,
aliphatic-substituted-aromatic, and heterocyclic. Nonlimiting
examples of suitable aliphatic and alicyclic diamines include
1,2-ethylene diamine, 1,2-porphylene diamine, 1,8-octane diamine,
isophorone diamine, propane-2,2-cyclohexyl amine, and the like.
Nonlimiting examples of suitable aromatic diamines include
phenylene diamines and the toluene diamines, for example,
o-phenylene diamine and p-tolylene diamine. These and other
suitable polyamines described in detail in U.S. Pat. No. 4,046,729
at column 6, line 61 to column 7, line 26, which is incorporated
herein by reference.
[0082] When desired, appropriate mixtures of curing agents may be
used. It should be mentioned that the compositions can be
formulated as a one-component composition where a curing agent such
as an aminoplast resin and/or a blocked isocyanate compound such as
those described above is admixed with other composition components.
The one-component composition can be storage stable as formulated.
Alternatively, compositions can be formulated as a two-component
composition where a polyisocyanate curing agent such as those
described above can be added to a pre-formed admixture of the other
composition components just prior to application. The pre-formed
admixture can comprise curing agents such as aminoplast resins
and/or blocked isocyanate compounds such as those described
above.
[0083] The curable coating compositions of the present invention
can be water-based compositions, solvent-based compositions, or
compositions in solid particulate form, e.g., a powder coating
composition. Typically, the curable coating composition is a
water-based composition.
[0084] In one particular embodiment of the present invention, the
reactive functional group-containing polymer (1) is dispersed in an
aqueous medium and comprises an aqueous dispersion of polymeric
microparticles. The microparticles can be crosslinked. A wide range
of crosslinked polymeric microparticle dispersions are suitable for
use herein including those described in U.S. Pat. No. 4,403,003 and
references cited therein. In a particular embodiment, the
microparticles contain greater than 30 percent by weight based on
the microparticles of a substantially hydrophobic polymer having a
molecular weight of greater than 300. Usually, the microparticles
contain greater than 40 percent by weight of the substantially
hydrophobic polymer, more preferably greater than 50 percent.
[0085] By "substantially hydrophobic" is meant that upon mixing a
sample of polymer with an organic component and water, a majority
of the polymer is in the organic phase and a separate aqueous phase
is observed. Examples of suitable substantially hydrophobic
polymers include polyester, polyurethane, polyether and alkyd
polymers such as those discussed in detail above (provided, of
course, that such polymers are substantially hydrophobic), which
are substantially free of repeating acrylic or vinyl units in the
backbone.
[0086] Also, it should be understood that the substantially
hydrophobic polymer is adapted to be chemically bound into the
cured coating composition. That is, the polymer is reactive in the
sense that it contains functional groups such as hydroxyl groups
which are capable of co-reacting, for example, with a crosslinking
agent, such as a melamine formaldehyde resin, which may be present
in the coating composition or, alternatively, with other film
forming resins which also may be utilized. The hydrophobic polymer
can have a molecular weight greater than 300, often greater than
500, and typically greater than 800. Usually, the number average
molecular weight ranges from 300 to 10,000, more often from 300 to
5,000.
[0087] As was mentioned above, the polyester, polyurethane, alkyd
and polyether polymers described above are examples of suitable
substantially hydrophobic polymers. The polyester resins contain
essentially no oil or fatty acid modification. That is, while alkyd
resins are in the broadest sense polyester type resins, they are
oil-modified and thus not generally referred to as polyester
resins. The polyesters are of two kinds. One type are the
unsaturated polyesters derived from unsaturated polyfunctional
acids and polyhydric alcohols. Maleic acid and fumaric acid are the
usual unsaturated acid components although methacrylic acid
unsaturated alcohols such as trimethylolpropane mono- or diallyl
esters can also be used. Commonly used polyhydric alcohols are
1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol,
propylene glycol, diethylene glycol, dipropylene glycol, butylene
glycol, glycerol, trimethylolpropane, pentaerythritol and sorbitol.
Often times a saturated acid will be included in the reaction to
provide desirable properties. Examples of saturated acids include
phthalic acid, isophthalic acid, adipic acid, azeleic acid, sebacic
acid, and the anhydrides thereof. The saturated polyesters are
derived from saturated or aromatic polyfunctional acids, preferably
dicarboxylic acids, and mixtures of polyhydric alcohols having an
average hydroxyl functionality of at least 2. Other components of
polyesters can include hydroxy acid and lactones such as ricinoleic
acids, 12-hydroxystearic acid, caprolactone, butyrolactone and
dimethylolopropionic acid.
[0088] The alkyds are polyesters of polyhydroxyl alcohols and
polycarboxylic acids chemically combined with various drying,
semi-drying and non-drying oils in different proportions. Thus, for
example, the alkyd resins are made from polycarboxylic acids such
as phthalic acid, maleic acid, fumaric acid, isophthalic acid,
succinic acid, adipic acid, azeleic acid, sebacic acid as well as
from anhydrides of such acids, where they exist. The polyhydric
alcohols which can be reacted with the polycarboxylic acid include
1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol,
diethylene glycol and 2,3-butylene glycol, glycerol,
trimethylolpropane, trimethylolpropane, pentaerythritol, sorbitol
and mannitol.
[0089] The alkyd resins are produced by reacting the polycarboxylic
acid and the polyhydric alcohols together with a drying,
semi-drying or non-drying oil in proportions depending upon the
properties desired. The oils are coupled into the resin molecule by
esterification during the manufacturing and become an integral part
of the polymer. The oil is fully saturated or predominately
unsaturated. When cast into films, the fully saturated oils tend to
crosslink and dry rapidly with oxidation to give more tough and
solvent resistant films. Suitable oils include coconut oil, fish
oil, linseed oil, tung oil, castor oil, cottonseed oil, safflower
oil, soybean oil, and tall oil. Various proportions of the
polycarboxylic acid, polyhydric alcohol and oil are used to obtain
alkyd resins of various properties as is well known in the art.
[0090] Examples of polyether polyols are polyalkylene ether polyols
such as those described above. With polyether polyols, it is
preferred that the carbon to oxygen weight ratio be high for better
hydrophobic properties. This it is preferred that the carbon to
oxygen ratio be greater than 3/1 and more preferably greater than
4/1.
[0091] The polyurethane polymers can be any of those described
above provided they are sufficiently substantially hydrophobic.
Examples of suitable polyurethane polymers also are described in
detail in U.S. Pat. No. 5,071,904 at column 4, lines 30 to 62
incorporated by reference herein.
[0092] The balance of the microparticle typically comprises an
ethylenically unsaturated monomer or a mixture of ethylenically
unsaturated monomers. These monomers hereinafter are referred to as
"polymerizable species". Examples of suitable materials include
acrylic monomers, for example alkyl esters of (meth)acrylic acid,
as well as vinyl aromatic monomers, for example styrene. Examples
of suitable ethylenically unsaturated monomers for this purpose can
be found in U.S. Pat. No. 5,071,904 at column 4, line 63 to column
5, line 11 incorporated by reference herein. The hydrophobic
polymer is substantially insoluble in the aqueous medium and is
also capable of being dissolved in the monomer or monomer mixture
which is utilized to prepare the polymer which comprises the
balance of the microparticle.
[0093] The dispersion of polymeric microparticles in an aqueous
medium is typically prepared by a high stress technique which is
described more fully below. First, the acrylic monomer or mixture
of such monomers utilized to prepare the polymer which comprises
the balance of the microparticle is thoroughly mixed with the
aqueous medium and the substantially hydrophobic polymer. For the
present application, the ethylenically unsaturated monomer or
mixture of such monomers together with the substantially
hydrophobic polymer is referred to as the "organic component". The
organic components generally also comprise other organic species
and usually is substantially free of organic solvent. That is, no
more than 20 percent of organic solvent is present. The mixture is
then subjected to stress in order to particulate it into
microparticles which are uniformly of a fine particle size. The
mixture is submitted to stress sufficient to result in a dispersion
such that after polymerization less than 20 percent of the polymer
microparticles have a mean diameter greater than 5 microns.
[0094] The aqueous medium provides the continuous phase of
dispersion in which the microparticles are suspended. The aqueous
medium is generally exclusively water. However, for some polymer
systems, it may be desirable to also include a minor amount of
inert organic solvent which can assist in lowering the viscosity of
the polymer to be dispersed. For example, if the organic phase has
a Brookfield viscosity greater than 1000 centipoise at 25.degree.
C. or a Gardner-Holdt bubble viscosity of "W", the use of some
solvent may be desirable. For some applications of the aqueous
microparticle dispersion, for example, in its present use as a
resinous binder for coating compositions, it may be desirable to
include a coalescing solvent in the coating composition. One can
conveniently include this coalescing solvent during the synthesis
of the polymer or in the latex as part of the organic component.
Examples of suitable water insoluble solvents which can be
incorporated in the organic component are benzyl alcohol, xylene,
methyl isobutyl ketone, mineral spirits, butanol, butyl acetate,
tributyl phosphate and dibutyl phthalate.
[0095] As was mentioned above, the mixture typically is subjected
to the appropriate stress by use of a MICROFLUIDIZER.RTM.
emulsifier which is available from Microfluidics Corporation in
Newton, Mass. The MICROFLUIDIZER high pressure impingement
emulsifier is described in detail in U.S. Pat. No. 4,533,254. The
device consists of a high pressure (up to 20,000 psi) pump and an
interaction chamber where the emulsification takes place. The pump
forces the mixture of reactants in aqueous medium into the chamber
where it is split into at least two streams which pass at very high
velocity through at least two slits and collide resulting in the
particulation of the mixture into small particles. Generally, the
reaction mixture passed through the emulsifier once at a pressure
between 5,000 and 15,000 psi. Multiple passes can result in smaller
average particle size and a narrower range for the particle size
distribution. When using the aforesaid MICROFLUIDIZER emulsifier,
stress is applied by liquid-liquid impingement as has been
described. However, it should be understood that if desired, other
modes of applying stress to the pre-emulsification mixture can be
utilized so long as sufficient stress is applied to achieve the
requisite particle size distribution, that is, such that after
polymerization less than 20 percent of the polymer microparticles
have a mean diameter greater than 5 microns. For example, one
alternative manner of applying stress would be the use of
ultrasonic energy.
[0096] Stress is described as force per unit area. Although the
precise mechanism by which the MICROFLUIDIZER emulsifier stresses
the pre-emulsification mixture to particulate it is not thoroughly
understood. It is theorized that stress is exerted in more than one
manner. It is believed that one manner in which stress is exerted
is by shear. Shear means that the force is such that one layer or
plane moves parallel to an adjacent, parallel plane. Stress can
also be exerted from all sides as a bulk, compression stress. In
this instance stress could be exerted without any shear. A further
manner of producing intense stress is by cavitation. Cavitation
occurs when the pressure within a liquid is reduced enough to cause
vaporization. The formation and collapse of the vapor bubbles
occurs violently over a short time period and produces intense
stress. Although not intending to be bound by theory, it is
believed that both shear and cavitation contribute to producing the
stress which particulates the preemulsification mixture.
[0097] Once the mixture has been particulated into microparticles,
the polymerizable species within each particle are polymerized
under conditions sufficient to produce polymer microparticles which
are stably dispersed in the aqueous medium. It should be understood
that one of the requisite conditions sufficient to achieve the
stably dispersed microparticles is the presence in the reaction
mixture of a surfactant which is also termed a dispersant. The
surfactant is preferably present when the organic component
referred to above is mixed into the aqueous medium, prior to
particularion. Alternatively, the surfactant can be introduced into
the medium at a point just after the particularion within the
MICROFLUIDIZER emulsifier. The surfactant, however, can be an
important part of the particle forming process and can be necessary
to achieve the requisite dispersion stability. The surfactant can
be a material that serves to prevent the emulsified particles from
agglomerating to form larger particles.
[0098] The same surfactants or dispersants which can be utilized
during conventional emulsion polymerization are also suitable for
this high stress technique. Examples of suitable surfactants
include the dimethylethanolamine salt of dodecylbenzenesulfonic
acid, sodium dioctylsulfosuccinate, ethoxylated nonylphenol and
sodium dodecyl benzene sulfonate. Other materials well known to
those skilled in the art are also suitable herein. Generally, both
ionic and nonionic surfactants are used together and the amount of
surfactant ranges from about 1 percent to about 10 percent,
preferably from about 2 percent to about 4 percent, the percentage
based on the total solids. One particularly preferred surfactant
for the preparation of aminoplast curable dispersions is the
dimethylethanolamine salt of dodecylbenzenesulfonic acid.
[0099] In order to conduct the free radical polymerization of the
polymerizable species, a free radical initiator typically is also
required. Both water soluble and oil soluble initiators can be
used. Since the addition of certain initiators, such as redox
initiators, can result in a strong exothermic reaction, it is
generally desirable to add the initiator to the other ingredients
immediately before the reaction is to be conducted. Examples of
water soluble initiators include ammonium peroxydisulfate,
potassium peroxydisulfate and hydrogen peroxide. Examples of oil
soluble initiators include t-butyl perbenzoate and
2,2'-azobis(isobutyronitrile). Preferably redox initiators such as
ammonium peroxydisulfate/sodium metabisulfite or
t-butylhydroperoxide/iso- ascorbic acid are utilized herein.
[0100] It should be understood that in some instances it may be
desirable for some of the reactant species to be added after
particulation of the remaining reactants and the aqueous medium
(for example, water soluble acrylic monomers such as hydroxypropyl
methacrylate). The particulated mixture is then subjected to
conditions sufficient to induce polymerization of the polymerizable
species, within the microparticles. The particular conditions will
vary depending upon the actual materials being polymerized. The
length of time required to complete polymerization typically varies
from about 10 minutes to about 6 hours. The progress of the
polymerization reaction can be followed by techniques
conventionally known to those skilled in the art of polymer
chemistry. For example, heat generation, monomer concentration and
percent of total solids are all methods of monitoring the progress
of the polymerization.
[0101] The aqueous microparticle dispersions can be prepared by a
batch process or a continuous process. In one batch process the
unreacted microdispersion is fed over a period of about 1 to 4
hours into a heated reactor initially charged with water. The
initiator can be fed in simultaneously, it can be part of the
microdispersion or it can be charged to the reactor before feeding
in the microdispersion. The optimum temperature depends upon the
specific initiator being used. The length of time typically ranges
from about 2 hours to about 6 hours.
[0102] In an alternative batch process, a reactor vessel is charged
with the entire amount of microdispersion to be polymerized.
Polymerization commences when an appropriate initiator such as a
redox initiator is added. An appropriate initial temperature is
chosen such that the heat of polymerization does not increase the
batch temperature beyond the boiling point of the ingredients. Thus
for large scale production, it is preferred that the
microdispersion have sufficient heat capacity to absorb the total
amount of heat being generated.
[0103] In a continuous process the pre-emulsion or mixture of raw
materials is passed through the homogenizer to make a
microdispersion which is immediately passed through a heated tube,
e.g., stainless steel, or a heat exchanger in which polymerization
takes place. The initiator is added to the microdispersion just
before it enters the tubing.
[0104] It is preferred to use redox type initiators in the
continuous process since other initiators can produce gases such as
nitrogen or carbon dioxide which can cause the latex to spurt out
of the reaction tubing prematurely. The temperature of reaction can
range from about 25.degree. C. to about 80.degree. C., preferably
about 35.degree. C. to about 45.degree. C. The residence time
typically ranges from about 5 minutes to about 30 minutes.
[0105] The tubing in which the reaction occurs is not required to
heat the microdispersion but rather to remove the heat being
generated. Once the initiator has been added, the reaction begins
spontaneously after a short induction period and the reaction
exotherm resulting from the polymerization will rapidly raise the
temperature.
[0106] If there is still free or unreacted monomer remaining after
all of the initiator is consumed, an additional amount of initiator
can be added to scavenge the remaining monomer.
[0107] Once the polymerization is complete, the resultant product
is a stable dispersion of polymer microparticles in an aqueous
medium, wherein both the polymer formed from the polymerizable
species and the substantially hydrophobic polymer are contained
within each microparticle. The aqueous medium, therefore, is
substantially free of water soluble polymer. The resultant polymer
microparticles are of course insoluble in the aqueous medium. In
saying that the aqueous medium is substantially free of water
soluble polymer, it is intended that the term "substantially free"
means that the aqueous medium contains no more than 30 percent,
often no more than 15 percent and typically no more than 10 percent
by weight of dissolved polymer.
[0108] By "stably dispersed" is meant that the polymer
microparticles do not hard settle upon standing and do not
coagulate or flocculate upon standing. Typically, when diluted to
50 percent total solids the microparticle dispersions do not settle
even when aged for one month at room temperature.
[0109] As was stated above, a very important aspect of the polymer
microparticle dispersions is that the particle size is uniformly
small, i.e., after polymerization less than 20 percent of the
polymer microparticies have a mean diameter which is greater than 5
microns, more preferably greater than 1 micron. Generally, the
microparticles have a mean diameter from about 0.01 microns to
about 10 microns. Preferably the mean diameter of the particles
after polymerization ranges from about 0.05 microns to about 0.5
microns. The particle size can be measured with a particle size
analyzer such as the Coulter N4 instrument commercially available
from Coulter. The instrument comes with detailed instructions for
making the particle size measurement. However, briefly, a sample of
the aqueous dispersion is diluted with water until the sample
concentration falls within specified limits required by the
instrument. The measurement time is 10 minutes.
[0110] The microparticle dispersions are high solids materials of
low viscosity. Dispersions can be prepared directly with a total
solids content of from about 45 percent to about 60 percent. They
can also be prepared at a lower solids lever of about 30 to about
40 percent total solids and concentrated to a higher level of
solids of about 55 to about 65 percent by stripping. The molecular
weight of the polymer and viscosity of the aqueous dispersions are
independent of each other. The weight average molecular weight can
range from few hundred to greater than 100,000. The Brookfield
viscosity can also vary widely from about 0.01 poise to about 100
poise, depending on the solids and composition, preferably from
about 0.2 to about 5 poise when measured at 25.degree. C. using an
appropriate spindle at 50 RPM.
[0111] The microparticle dispersion can be either crosslinked or
uncrosslinked. When uncrosslinked the polymer within the
microparticle can be either linear or branched.
[0112] The curable coating compositions of the present invention
can contain, in addition to the components described above, a
variety of other optional materials. As was mentioned above, if
desired, other resinous materials can be utilized in conjunction
with the dispersion of polymeric microparticles so long as the
resultant coating composition is not detrimentally affected in
terms of physical performance and properties. In addition, material
such as rheology control agents, ultraviolet light stabilizers,
catalysts, fillers and the like can be present.
[0113] In one embodiment, the present invention is directed to a
curable coating composition such as any of the previously described
curable coating compositions, wherein the reaction product (3) is
present in an amount sufficient to provide viscosity stability of
the composition such that the viscosity of the composition,
typically as determined in accordance with ASTM D1200-99, increases
not more than 50%, usually not more than 35%, and typically not
more than 20%, upon storage for 16 hours at a temperature ranging
from 49.degree. C. to 71.degree. C.
[0114] The curable composition of the present invention can be a
substantially pigment-free composition, for example, a clear coat
in a color-plus-clear system, or, alternatively, a
pigment-containing composition, for example a monocoat or a
basecoat in a color-plus-clear system. The pigments which can be
utilized are of various types, depending upon whether a metallic
pigment is desired. When a metallic coating is desired preferably
aluminum flake is utilized. A variety of grades of aluminum flake
are available such as Silberline Sparkle Silver 5000 AR, Toyo 8260
and Obron OBT 8167 STAPA M. Also chrome treated aluminum flake such
as Hydrolux 400 and Ekkert 47700 can be used. Other metallic
pigments include bronze flakes, coated mica, nickel flakes, tin
flakes, silver flakes, copper flakes, or combination of these.
Other examples of suitable pigments include mica, iron oxides, lead
oxides, carbon black, titanium dioxide, talc, as well as a variety
of color pigments. The specific pigment to binder ratio can vary
widely so long as it provides the requisite hiding at the desired
film thickness and application solids.
[0115] The curable coating compositions can be applied by
conventional means including brushing, dipping, flow coating,
spraying and the like, but they are most often applied by spraying.
Conventionally known spray techniques and equipment for air
spraying and electrostatic spraying and either manual or automatic
methods can be used.
[0116] In one embodiment, the present invention is directed to an
improved multilayer composite coating comprising a first coating
layer deposited over at least a portion of a substrate from a first
curable coating composition, and a second coating layer deposited
over at least a portion of the first coating layer, the second
coating layer formed from a second curable coating composition. The
first coating layer, for example, a base coat in a color-plus-clear
system, can be formed from any of the previously described curable
coating compositions of the present invention.
[0117] During application of the first curable coating composition
to the substrate, a first coating layer is formed over at least a
portion of the substrate. Typically, the first coating layer dry
film thickness will range from 0.01 to 5 mils (0.25 to 127
micrometers), and typically 0.1 to 2 mils (2.5 to 51 micrometers)
in thickness.
[0118] As mentioned above, after application of the first curable
coating composition, a film is formed on at least a portion of the
surface of the substrate. This is achieved by driving solvent,
i.e., organic solvent and/or water, out of the film by heating or
simply by an air-drying period. Preferably, the heating step will
be for a period sufficient to ensure that the second curable
coating composition can be applied to the first coating layer
without dissolving the first coating layer i.e., "striking in".
[0119] Suitable drying conditions will depend on the particular
first coating composition, on the ambient humidity with certain
waterbased compositions, but in general, a drying time of from 1 to
5 minutes at a temperature of 1000 to 250.degree. F. (39.degree. to
121.degree. C.) will be adequate to ensure that mixing of the two
coats is minimized. At the same time, the first coating layer is
adequately wetted by the second coating composition so that
satisfactory intercoat adhesion is obtained.
[0120] The multilayer composite coating is characterized in that
the reaction product (3) is present in the first coating
composition in an amount sufficient to provide at least 50%,
usually at least 75%, and typically at least 80% adhesion between
the coating and the substrate as determined by ASTM-D3359-97. Also,
it should be understood that as used herein, a coating layer or
composition formed "over" at least a portion of a "substrate"
refers to a coating layer or composition formed directly on at
least a portion of the substrate surface, as well as to a coating
layer or composition formed over any coating or adhesion promoter
material which was previously applied to at least a portion of the
substrate.
[0121] That is, the "substrate" upon which the first coating layer
is formed can comprise a metallic or elastomeric substrate to which
one or more coating layers have been previously applied. For
example, the "substrate" can comprise a metallic substrate and a
weldable primer coating over at least a portion of the substrate
surface, and the first polymeric layer can comprise an
electrodepositable primer coating. Likewise, the "substrate" can
comprise a metallic substrate having an electrodepositable primer
formed over at least a portion thereof, and a primer-surfacer
coating over at least a portion of the electrodepositable primer.
The first coating layer of the multilayer composite coating of the
present invention can comprise, for example, a pigmented base coat
over at least a portion of this multli-layer "substrate", and the
second coating layer can comprise a pigment-free top coat formed
over at least a portion of the pigmented base coat.
[0122] Also, more than one first coating and multiple second
coating compositions may be applied to develop the optimum
appearance. Usually between coats, the previously applied coating
is flashed, that is, exposed to ambient conditions for about 1 to
20 minutes. The second coating composition can be applied to the
coated substrate by any of the conventional coating techniques
described above in connection with the first coating, however spray
applications tend to give the best appearance properties.
[0123] After application of the second coating composition to the
first coating layer, the coated substrate is heated to cure the
coating layers. The heating or curing operation is usually carried
out at a temperature in the range of from 1600 to 350.degree. F.
(710 to 177.degree. C.), but if needed lower or higher temperatures
may be used depending upon whether it is sufficient to activate any
necessary crosslinking mechanisms. It should be understood that for
the purposes of the present invention the term "curing" also
includes drying.
[0124] The dry film thickness of the second coating layer can range
from 0.5 to 5 mils (12.7 to 127.0 micrometers), and typically from
1.2 to 3 mils (30.5 to 76.2 micrometers).
[0125] As mentioned above, the present invention is also directed
to a coated substrate comprising a substrate, such as any of the
"substrates" described above, and a cured coating layer over at
least a portion of the substrate. The cured coating layer can be
formed from any of the curable coating compositions described
above.
[0126] The invention will be further described by reference to the
following examples. Unless otherwise indicated, all parts are by
weight.
EXAMPLES
[0127] Example A below describes preparation of the polyether
carbamate additive of the invention. Examples B through F describe
the preparation of polymers used in the preparation of the tints
and base coats. Examples 1 through 8 describe white base coat
formulations. Example 1 is a comparative example. Examples 9
through 11 describe black base coat formulations. Example 9 is a
comparative example. Examples 12 through 16 describe silver base
coat formulations. Example 12 is a comparative example. Examples 13
and 14 describe silver base coats with addition of the polyether
carbamate of Example A. Examples 15 and 16 are comparative
examples, which are the same as Examples 13 and 14 except for the
replacement of the polyether carbamate of Example A with a
competitive urethane diol additive.
Example A
Preparation of the Polyether Carbamate Additive
[0128] A hydroxy functional polyether carbamate was prepared from
the following ingredients:
1 Ingredients Amount (grams) Equivalents JEFFAMINE D 400.sup.1 2000
10 Ethylenecarbonate 968 11 .sup.1Polypropyleneoxide amine from
Huntsman Corporation, Texas.
[0129] PROCEDURE: Both the ingredients were added to the reaction
vessel and heated to 130.degree. C. The reaction mixture was held
at this temperature till greater than 90% of the amine was reacted
as measured by potentiometric titration of the mixture, in which
the mixture was solubilized in acetic acid and titrated with 0.1 N
(normal) perchloric acid in glacial acetic acid. The product was
slightly yellowish, had a theoretical % weight solids of 100%, and
weight averaged molecular weight of 800 as measured by gel
permeation chromatography using polystyrene as internal
standard.
Example B
Preparation of Acrylic Latex Used in Basecoats of Examples 1-16
[0130] Preparation of Isostearic acid polyester. A polyester was
prepared in a four-neck round bottom flask equipped with a
thermometer, mechanical stirrer, condenser, dry nitrogen sparge,
and a heating mantle. The following ingredients were used:
2 Component Amount (grams) Isostearic acid 1103.0 Pentaerythritol
800.0 Crotonic acid 470.0 Phthalic anhydride 688.0 Dibutyltin oxide
6.1 Triphenyl phosphite 6.1 Butyl acrylate 1170.0 NAUGARD .RTM.
BHT.sup.1 4.0 .sup.1Butylated hydroxytoluene antioxidant available
from Merisol Antioxidants, L.L.C.
[0131] The first six ingredients were stirred in the flask at a
temperature of 210.degree. C. until 245 ml of distillate was
collected and the acid value dropped to 4.6. The material was
cooled to 77.degree. C. and the last two ingredients were stirred
in. The final product was a viscous yellow liquid with a hydroxyl
value of 54.0, a Gardner-Holdt viscosity of Z+, a weight average
molecular weight of 45,600, and a non-volatile content of
70.2%.
[0132] Preparation of Latex: A pre-emulsion was prepared by
stirring together the following ingredients:
3 Component Amount (grams) Isostearic acid polyester described
above 286.0 butyl acrylate 664.0 Ethylene glycol dimethacrylate
30.0 acrylic acid 20.0 Dodecylbenzenesulfonic acid (70% in
isopropanol) 46.4 Dimethylethanolamine 14.3 Water 1000.0
[0133] The pre-emulsion was passed once through a
Microfluidizer.RTM..RTM. M110T at 8000 psi and transferred to a
four-neck round bottom flask equipped with an overhead stirrer,
condenser, thermometer, and a nitrogen atmosphere. One hundred
fifty grams (150.0 g) of water used to rinse the
Microfluidizer.RTM. was added to the flask. The polymerization was
initiated by adding 3.0 g of isoascorbic acid and 0.02 g of ferrous
ammonium sulfate dissolved in 120.0 g water followed by a ten
minute addition of 5.0 g of 70% t-butyl hydroperoxide dissolved in
115.0 g of water. The temperature of the reaction increased from
23.degree. C. to 80.degree. C. The temperature was reduced to
<30.degree. C. and 1.0 g of isoascorbic acid dissolved in 8.0 g
water was added. Ten minutes later 17 g of 33.3% aqueous
dimethylethanolamine was added followed by 2.0 g of PROXEL GXL
(Biocide available from ICI Americas, Inc.) in 8.0 g of water.
[0134] The final pH of the latex was 6.1, the nonvolatile content
was 42.4%, the particle size was 105 nm, and the Brookfield
viscosity was 14 cps (spindle #1, 50 rpm).
Example C
Preparation of Acrylic Grind Vehicle used in Examples G, H, and
12-16
[0135] The acrylic grind vehicle was prepared from the following
ingredients:
4 Ingredients Weight in grams Feed A: butyl ether of diethylene
glycol 200.0 Water 32.0 Feed B: Styrene 255.0 butyl acrylate 297.5
butyl methacrylate 153.0 hydroxyethyl methacrylate 72.3 acrylic
acid 72.3 Feed C: tertiary butyl peracetate 14.5 butyl ether of
diethylene glycol 140.0 Feed D: 50% aqueous dimethylethanol amine
59.0 Feed E: Water 1971.0
[0136] A suitable reactor was charged with feed A and heated to
reflux. Feeds B and C were then added simultaneously over 3 hours,
followed by a one hour hold. The reaction product was then cooled
below 100.degree. C. and feed D was added. Finally, Feed E,
preheated to 70.degree. C., was added slowly. The final product had
solid content of about 25%.
Example D
Preparation of Acid Functional Polyester Used in Examples 12-16
[0137] A polyacid half-ester of
1-(3-hydroxy-2,2-dimethylpropyl)-3-hydroxy- -2,2-dimethylpropionate
(ESTER DIOL 204) and methylhexahydrophthalic anhydride was prepared
from the following mixture of ingredients:
5 Parts by Weight (in Component grams) ESTER DIOL 204.sup.1 2550.0
Methylhexahydrophthalic anhydride 4116.0 Methyl isobutyl ketone
1466.5 Ethanol 666.6 .sup.1Available from Union Carbide.
[0138] The ESTER DIOL 204 and 1466.5 grams of the methyl isobutyl
ketone were charged to a reaction vessel and heated under a
nitrogen atmosphere to 115.degree. C. The methylhexahydrophthalic
anhydride was added over a 90-minute period. The reaction mixture
was then held at 115.degree. C. for four hours. The reaction
mixture was then cooled to 100.degree. C. followed by the addition
of ethanol (to react with residual anhydride) and heating the
reaction mixture to reflux and holding for two hours. The reaction
mixture was stripped under vacuum to a pot temperature of
125.degree. C. The reaction mixture was then adjusted to 80 percent
solids with methyl isobutyl ketone.
Example E
Preparation of Polyester Polymer Used in Examples 9 through 11
[0139]
6 Parts by Weight (in Component grams) 1,4-Cyclohexane Dicarboxylic
Acid 344.0 Isostearic Acid 568.0 Trimethylol propane 540.0
Triphenyl phosphite 3.60 Dibutyltin Oxide 2.60
[0140] The above components were charged into a three-liter,
four-necked round bottom flask equipped with a motor driven
stainless steel paddle agitator, a thermocouple to record batch
temperature, a Dean-Stark water trap connected with a condenser to
collect distillate evolved, and a nitrogen sparge tube.
[0141] The synthesis was performed using azeotropic conditions with
xylene (3% on solids). Heat was applied to a Glas-Col heating
mantle and the temperature was gradually increased to about
220.degree. C. and held until an acid value of less than four was
obtained.
Example F
Preparation of Acrylic Grind Vehicle Used in Example G
[0142] A polyurethane acrylate was prepared from the following
ingredients:
7 Materials Amount (grams) Polyester polyol.sup.1 934.0
hydroxyethyl acrylate (HEA) 108.0 dibutyltin dilaurate 1.2 IONOL
1.2 Hexamethylenediisocyanate (HDI) 157.2 butyl acrylate (BA) 262.2
.sup.1Polyester polyol having a hydroxyl value of 120 prepared from
trimethylolpropane (15.2 weight %), neopentyl glycol (35.3 weight
%), and adipic acid (49.5 weight %).
[0143] The first four ingredients were stirred in a flask as the
HDI was added over a one hour period at a temperature of
70.degree.-80.degree. C. 39 g of the butyl acrylate was used to
rinse the addition funnel containing the HDI and the temperature of
the mixture was then held at 70.degree. C. for an additional 2
hours as all the isocyanate reacted. The remainder of the butyl
acrylate was added to produce an 80% solution with a Gardner-Holdt
viscosity of X.
[0144] A pre-emulsion was made by stirring together the
following:
8 Material Amount (grams) Polyurethane acrylate described above
1003.8 butyl acrylate 98.8 Methyl methacrylate 147.0 Acrylic acid
20.6 Dimethylethanolammonium dodecylbenzene sulfonate, 13.52 50% in
water (DDBSA/DMEA) Alipal Co 436.sup.1, 46.16 AEROSOL OT-75.sup.2
17.92 Water 1246.0 .sup.1Anionic surfactant, available from Rhodia
Chemicals. .sup.2Sodium dioctylsulfosuccinate commercially
available from Cytec Industries, Inc.
[0145] The pre-emulsion was passed once through a M110
Microfluidizer.RTM. emulsifier at 7000 is to produce a
microdispersion. The microdispersion was stirred at 22.degree. C.
under nitrogen in a round bottom flask and the following solutions
were added.
9 Material Amount (grams) deionized water 429.9 isoascorbic acid
2.0 1% aqueous ferrous ammonium sulfate 2.86 30% aqueous hydogen
peroxide 2.94 dimethylethanol amine 21.5
[0146] The temperature rose spontaneously to 56.degree. C. within
15 minutes. The final product had the following characteristics:
total solids was 42%; pH was 8.3; Brookfield viscosity (50 rpm,
spindle #1) was 14 centistokes per second; and average particles
size was 201 nm.
Example G
Preparation of White Tint Used in Examples 1 through 8
[0147] The following were added to a vessel in order.
10 Amount (parts by Component weight) Deionized Water 125.933 Add
under agitation Acrylic Grind Vehicle of Example C 235.476 Acrylic
Grind Vehicle of Example F 145.753 DOWANOL PM.sup.1 10.603 ARCOL
PPG-425.sup.2 20.506 DOWANOL PNB.sup.3 30.724 DOWANOL DPM.sup.4
33.024 Shell Odorless Mineral Spirits.sup.5 25.347 Dimethyl
ethanolamine 50% in water 11.509 Mix 5 minutes at low rpm then add
R-900-39 E.D. TiO.sub.2 1109.754 .sup.1Propylene glycol monomethyl
ether available from Dow Chemical Company. .sup.2Polypropylene
glycol available from Dow Chemical Company. .sup.3Propylene glycol
n-butyl ether available from Dow Chemical Company.
.sup.4Dipropylene glycol monomethyl ether available from Dow
Chemical Company. .sup.5Available from Shell Oil and Chemical
Company.
[0148] The mixture was mixed by cowles blade for 60 minutes at high
speed. Then the following ingredients were added under
agitation:
11 Amount (parts by Component weight) Deionized Water 52.997
DOWANOL PM 20.194 ARCOL PPG-425 20.194 Dimethyl ethanolamine 50% in
water 11.509
Example H
Preparation of Black Tint Used in Examples 9 through 11
[0149] The following components were premixed under agitation for
five minutes:
12 Amount (parts by Component weight) DOWANOL PM 52.885 DOWANOL
PNP.sup.1 52.885 Deionized Water 97.886 Acrylic Grind Vehicle of
Example C. 587.250 50% Dimethyl ethanolamine solution in water
11.509 .sup.1Propylene glycol n-propyl ether available from Dow
Chemical Company.
[0150] 54.173 parts by weight of Monarch 1300 Black Pigment
(available from Cabot Specialty Chemicals) was then added over a
period of no more than 15 minutes and predispersed with a cowles
blade. The predispersion was milled for 11 hours with 1.6 mm steel
media at 80 gallons per hour in a dual chamber Premier mill. In the
dual chamber Premier mill configuration, the material is
recirculated through two Premier mill chambers which are connected
in series.
[0151] The pH was adjusted after the first pass to 7.85 to 8.20
with a 50% solution of dimethyl ethanolamine in water.
Comparative Example 1
Preparation of White Aqueous Basecoat
[0152]
13 Parts by Weight Component (grams) AQUEOUS PORTION Deionized
Water 35.0 Shell Odorless Mineral Spirits.sup.1 15.0 Acrylic Latex
of Example B 158.0 White Tint of Example G 225.0 ORGANIC PORTION
DOWANOL PNB 37.0 CYMEL 303LF.sup.2 37.0 Propylene Glycol 13.0
.sup.1Available from Shell Oil and Chemical Company. .sup.2Melamine
crosslinker available from Cytec Industries, Inc.
[0153] The aqueous portion of the white basecoat was assembled by
adding each component under agitation in the order shown and mixing
the mixture for 10 minutes. In a separate vessel, the three
components of the organic portion were combined and mixed until
uniform. The organic portion was added to the aqueous portion
slowly under agitation. The mixture of the aqueous and organic
portions was agitated for 20 minutes.
[0154] The pH was adjusted to 8.5 to 8.7 with a 50% solution of
dimethylethanol amine and deionized water. The paint was allowed to
equilibrate for 24 hours and, if necessary, a final pH adjustment
was made as described above. The paint was reduced with deionized
water to a viscosity of 28 to 30 seconds using a #4 Ford Cup
accordance with ASTM D 1200-99 before spraying.
Example 2
Addition of 2% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0155] To 1021 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
5 parts by weight of the polyether carbamate additive of Example A.
The additive of Example A was added under agitation and agitation
was continued until the mixture was uniform. The resulting white
aqueous basecoat contained 2% of the resin solids of Example A
based on the weight of the resin solids of the mixture of Example A
and Comparative Example 1.
Example 3
Addition of 5% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0156] To 1004 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
12 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 5% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Example 4
Addition of 10% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0157] To 520 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
12.5 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 10% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Example 5
Addition of 15% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0158] To 944 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
37 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 15% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Example 6
Addition of 20% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0159] To 496 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
25 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 20% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Example 7
Addition of 30% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0160] To 857 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
74 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 30% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Example 8
Addition of 54% on Resin Solids of the Additive of Example A to the
White Aqueous Basecoat of Comparative Example 1
[0161] To 721 parts by weight of the white aqueous basecoat of
Comparative Example 1, before letdown to spray viscosity, was added
131 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting white aqueous basecoat contained 54% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 1.
Comparative Example 9
Preparation of Black Aqueous Basecoat
[0162]
14 Parts by Weight (in COMPONENT grams) AQUEOUS PORTION Shell
Odorless Mineral Spirits.sup.1 13.5 Acrylic Latex of Example B
132.0 Deionized Water 88.5 Urethane Resin.sup.2 13.0 Black Tint of
Example H 57.0 50% Dimethylethanolamine in Water 1.0 ORGANIC
PORTION N-butoxypropanol 40.0 N-methyl-2-pyrrolidone 6.0 CYMEL 327
42.0 TINUVIN 1130.sup.3 3.4 Polyester Resin of Example E 6.3
Phosphatized Epoxy Resin.sup.4 1.0 .sup.1Available from Shell Oil
and Chemical Company. .sup.2Daotan VTW6462/36WA available from
Solutia, Inc. .sup.3Available from Ciba Specialty Chemicals, Inc.
.sup.4Phosphatized epoxy prepared from EPON 828 (a polyglycidyl
ether of Bisphenol A, available from Shell Oil and Chemical Co.);
reacted with phosphoric acid at a weight ratio of 83:17.
[0163] The aqueous portion of the black basecoat was assembled from
the components listed above. Each component was added under
agitation and the mixture was mixed for 10 minutes. In a separate
vessel, the components of the organic portion listed above were
combined in the order shown and agitated until well dispersed. The
Organic Portion was then were added to the Aqueous Portion by slow
addition under agitation. The mixture of the Aqueous Portion and
the Organic Portion was agitated for 20 minutes. The pH was
adjusted to 8.5 to 8.7 with a 50% solution of dimethylethanol amine
and deionized water. The paint was allowed to equilibrate for 24
hours and, if necessary, a final pH adjustment was made as
described above. The paint was reduced with deionized water to a
viscosity of 28 to 30 seconds using a #4 Ford Cup in accordance
with ASTM D 1200-99 before spraying.
Example 10
Addition of 10% on Resin Solids of the Additive of Example A to the
Black Aqueous Basecoat of Comparative Example 9
[0164] To 380 parts by weight of the black aqueous basecoat of
Comparative Example 9, before letdown to spray viscosity, was added
12 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting black aqueous basecoat contained 10% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 9.
Example 11
Addition of 20% on Resin Solids of the Additive of Example A to the
Black Aqueous Basecoat of Comparative Example 9
[0165] To 356 parts by weight of the black aqueous basecoat of
Comparative Example 9, before letdown to spray viscosity, was added
24 parts by weight of the polyether carbamate additive of Example
A. The additive of Example A was added under agitation and
agitation was continued until the mixture was uniform. The
resulting black aqueous basecoat contained 20% of the resin solids
of Example A based on the weight of the resin solids of the mixture
of Example A and Comparative Example 9.
Comparative Basecoat Examples in Silver Color Comparative Example
12
Preparation of Silver Basecoat with No Polyether Carbamate
Additive
[0166]
15 Parts by Weight (in Component grams) Aqueous Portion Shell
Odorless Mineral Spirits.sup.1 6.0 Acrylic Latex of Example B 140.0
Deionized water 50.0 Acrylic Grind Vehicle of Example C 23.1 50%
solution of Dimethylethanol amine in Water 2.2 Organic Portion
N-Butoxypropanol 45.04 CYMEL 303LF 25.00 CYMEL 385.sup.2 6.25
TINUVIN 1130 1.40 AQUA PASTE 3620-D23.sup.3 23.50 AQUA PASTE
3700-A23.sup.4 6.50 Phosphatized Epoxy.sup.5 0.39 Thickener Portion
Deionized water 10.0 50% solution of Dimethylethanol amine in Water
2.5 Acid Functional Polyester of Example D 5.0 .sup.1Available from
Shell Oil and Chemical Company. .sup.2Melamine crosslinker
available from Cytec Industries, Inc. .sup.3Available from
Silberline Mfg. .sup.4Available from Silberline Mfg.
.sup.5Phosphatized epoxy prepared from EPON 828 (a polyglycidyl
ether of Bisphenol A, available from Shell Oil and Chemical Co.);
reacted with phosphoric acid at a weight ratio of 83:17.
[0167] The aqueous portion of the silver basecoat was assembled
from the components listed above. Each component was added under
agitation in the order shown and the mixture was mixed for 10
minutes.
[0168] In a separate vessel the first four components of the
organic portion listed above were combined and then agitated until
well dispersed. The next two materials were then added under
agitation and mixed for 20 minutes or until well dispersed. The
last material was added under agitation until dispersed. The
organic portion was added slowly to the aqueous portion and
agitated for 20 minutes. The pH was adjusted to 8.5-8.7 with a 50%
solution of dimethylethanol amine and deionized water.
[0169] In a separate container, the thickener portion of the
basecoat was prepared by combining the three materials listed above
under agitation and mixing for 20 minutes.
[0170] The thickener portion was then added and again the pH was
adjusted Is to 8.5-8.7. The paint was allowed to equilibrate for 24
hours before the final pH adjustment was made. The paint was then
reduced with deionized water before spraying to a viscosity of
25-27 seconds using a 4 Ford Cup accordance with ASTM D
1200-99.
Example 13
Preparation of Silver Basecoat with 7% on Resin Solids of the
Polyether Carbamate Additive of Example A
[0171]
16 Parts by Weight (in Component grams) Aqueous Portion Shell
Odorless Mineral Spirits.sup.1 6.00 Acrylic Latex of Example B
123.13 Deionized water 50.00 Acrylic Grind Vehicle of Example C
23.10 50% solution of Dimethylethanol amine in Water 2.20 Organic
Portion N-Butoxypropanol 45.04 CYMEL 303LF 25.00 CYMEL 385 6.25
TINUVIN 1130 1.40 AQUA PASTE 3620-D23 23.50 AQUA PASTE 3700-A23
6.50 Phosphatized Epoxy.sup.2 0.39 Thickener Portion Deionized
water 10.00 50% solution of Dimethylethanol amine in Water 2.50
Acid Functional Polyester of Example D 5.00 Polyoxyalkylene
Carbamate Addition Additive of Example A 7.00 .sup.1Available from
Shell Oil and Chemical Company. .sup.2Phosphatized epoxy prepared
from EPON 828 (a polyglycidyl ether of Bisphenol A, available from
Shell Oil and Chemical Co.); reacted with phosphoric acid at a
weight ratio of 83:17.
[0172] An addition of 7% based on total resin solids of the
additive of Example A was made to the silver basecoat by reducing
the Acrylic Latex of Example B by 7% on resin solids. The additive
of Example A was post-added to the coating as described below.
[0173] The aqueous portion of a silver basecoat was assembled from
the components listed above. Each component was added under
agitation in the order shown and the mixture was mixed for 10
minutes.
[0174] In a separate vessel the first four components of the
organic portion listed above were combined and then agitated until
well dispersed. The next two materials were then added under
agitation and mixed until well dispersed. The last material was
added under agitation until dispersed.
[0175] In a separate container, the thickener portion of the
basecoat was prepared by combining under agitation the three
materials listed above and mixing for 20 minutes.
[0176] The organic portion was added slowly to the aqueous portion
and agitated for 20 minutes. The pH was adjusted to 8.5-8.7 with a
50% solution of dimethylethanol amine and deionized water. The
thickener portion was then added and again the pH was adjusted to
8.5-8.7.
[0177] The additive of Example A was added before the reduction of
the basecoat to spray viscosity.
[0178] The paint was allowed to equilibrate for 24 hours before the
final pH adjustment was made. The paint was then reduced with
deionized water before spraying to a viscosity of 25-27 seconds
using a 4 Ford Cup accordance with ASTM D 1200-99.
Example 14
Preparation of Silver Basecoat with 15% on Resin Solids of the
Polyether Carbamate Additive of Example A
[0179]
17 Parts by Weight (in Component grams) Aqueous Portion Shell
Odorless Mineral Spirits.sup.1 6.00 Acrylic Latex of Example B
103.85 Deionized water 50.00 Acrylic Grind Vehicle of Example C
23.10 50% solution of Dimethylethanol amine in Water 2.20 Organic
Portion N-Butoxypropanol 45.04 CYMEL 303LF 25.00 CYMEL 385 6.25
TINUVIN 1130 1.40 AQUA PASTE 3620-D23 23.50 AQUA PASTE 3700-A23
6.50 Phosphatized Epoxy.sup.2 0.39 Thickener Portion Deionized
water 10.00 50% solution of Dimethylethanol amine in Water 2.50
Acid Functional Polyester of Example D 5.0 Polyoxyalkylene
Carbamate Addition Additive of Example A 15.0 .sup.1Available from
Shell Oil and Chemical Company. .sup.2Phosphatized epoxy prepared
from EPON 828 (a polyglycidyl ether of Bisphenol A, available from
Shell Oil and Chemical Co.); reacted with phosphoric acid at a
weight ratio of 83:17.
[0180] An addition of 15% based on total resin solids of the
additive of Example A was made to the silver basecoat by reducing
the Acrylic Latex of Example B by 15% on resin solids. The additive
of Example A was post-added to the coating as described below.
[0181] The aqueous portion of a silver basecoat was assembled from
the components listed above. Each component was added under
agitation in the order shown and the mixture was mixed for 10
minutes.
[0182] In a separate vessel the first four components of the
organic portion listed above were combined and then agitated until
well dispersed. The next two materials were then added under
agitation and mixed until well dispersed. The last material was
added under agitation until dispersed.
[0183] In a separate container, the thickener portion of the
basecoat was prepared by combining under agitation the three
materials listed above and mixing for 20 minutes.
[0184] The organic portion was added slowly to the aqueous portion
and agitated for 20 minutes. The pH was adjusted to 8.5-8.7 with a
50% solution of dimethylethanol amine and deionized water. The
thickener portion was then added and again the pH was adjusted to
8.5-8.7.
[0185] The additive of Example A was added before the reduction of
the basecoat to spray viscosity.
[0186] The paint was allowed to equilibrate for 24 hours before the
final pH adjustment was made. The paint was then reduced with
deionized water before spraying to a viscosity of 25-27 seconds
using a 4 Ford Cup accordance with ASTM D 1200-99.
Comparative Example 15
Preparation of Silver Basecoat with 7% on Resin Solids of
Competitive Additive
[0187]
18 Parts by Weight (in Component grams) Aqueous Portion Shell
Odorless Mineral Spirits.sup.1 6.00 Acrylic Latex of Example B
123.13 Deionized water 50.00 Acrylic Grind Vehicle of Example C
23.10 50% solution of Dimethylethanol amine in Water 2.20 Organic
Portion N-Butoxypropanol 45.04 CYMEL 303LF 25.00 CYMEL 385 6.25
TINUVIN 1130 1.40 AQUA PASTE 3620-D23 23.50 AQUA PASTE 3700-A23
6.50 Phosphatized Epoxy.sup.2 0.39 Thickener Portion Deionized
water 10.00 50% solution of Dimethylethanol amine in Water 2.50
Acid Functional Polyester of Example D 5.00 Competitive Additive
Addition K-FLEX XM4306.sup.3 7.0 .sup.1Available from Shell Oil and
Chemical Company. .sup.2Phosphatized epoxy prepared from EPON 828
(a polyglycidyl ether of Bisphenol A, available from Shell Oil and
Chemical Co.); reacted with phosphoric acid at a weight ratio of
83:17. .sup.3Available from King Industries
[0188] An addition of 7% based on total resin solids of the
additive of Example A was made to the silver basecoat by reducing
the Acrylic Latex of Example B by 7% on resin solids. The additive
of Example A was post-added to the coating as described below.
[0189] The aqueous portion of a silver basecoat was assembled from
the components listed above. Each component was added under
agitation in the order shown and the mixture was mixed for 10
minutes.
[0190] In a separate vessel the first four components of the
organic portion listed above were combined and then agitated until
well dispersed. The next two materials were then added under
agitation and mixed until well dispersed. The last material was
added under agitation until dispersed.
[0191] In a separate container, the thickener portion of the
basecoat was prepared by combining under agitation the three
materials listed above and mixing for 20 minutes.
[0192] The organic portion was added slowly to the aqueous portion
and agitated for 20 minutes. The pH was adjusted to 8.5-8.7 with a
50% solution 5 of dimethylethanol amine and deionized water. The
thickener portion was then added and again the pH was adjusted to
8.5-8.7.
[0193] The additive of Example A was added before the reduction of
the basecoat to spray viscosity.
[0194] The paint was allowed to equilibrate for 24 hours before the
final pH adjustment was made. The paint was then reduced with
deionized water before spraying to a viscosity of 25-27 seconds
using a 4 Ford Cup accordance with ASTM D 1200-99.
Comparative Example 16
Preparation of Silver Basecoat with 15% on Resin Solids of
Competitive Additive
[0195]
19 Parts by Weight (in Component grams) Aqueous Portion Shell
Odorless Mineral Spirits.sup.1 6.00 Acrylic Latex of Example B
103.85 Deionized water 50.00 Acrylic Grind Vehicle of Example C
23.10 50% solution of Dimethylethanol amine in Water 2.20 Organic
Portion N-Butoxypropanol 46.04 CYMEL 303LF 25.00 CYMEL 385 6.25
TINUVIN 1130 1.40 AQUA PASTE 3620-D23 23.50 AQUA PASTE 3700-A23
6.50 Phosphatized Epoxy.sup.2 0.39 Thickener Portion Deionized
water 10.00 50% solution of Dimethylethanol amine in Water 2.50
Acid Functional Polyester of Example D 5.0 Competetive Additive
Addition K-FLEX XM4306 15.0 .sup.1Available from Shell Oil and
Chemical Company. .sup.2Phosphatized epoxy prepared from EPON 828
(a polyglycidyl ether of Bisphenol A, available from Shell Oil and
Chemical Co.); reacted with phosphoric acid at a weight ratio of
83:17.
[0196] An addition of 15% based on total resin solids of the
additive of Example A was made to the silver basecoat by reducing
the Acrylic Latex of Example B by 15% on resin solids. The additive
of Example A was post-added to the coating as described below.
[0197] The aqueous portion of a silver basecoat was assembled from
the components listed above. Each component was added under
agitation in the order shown and the mixture was mixed for 10
minutes.
[0198] In a separate vessel the first four components of the
organic portion listed above were combined and then agitated until
well dispersed. The next two materials were then added under
agitation and mixed until well dispersed. The last material was
added under agitation until dispersed.
[0199] In a separate container, the thickener portion of the
basecoat was prepared by combining under agitation the three
materials listed above and mixing for 20 minutes.
[0200] The organic portion was added slowly to the aqueous portion
and agitated for 20 minutes. The pH was adjusted to 8.5-8.7 with a
50% solution of dimethylethanol amine and deionized water. The
thickener portion was then added and again the pH was adjusted to
8.5-8.7.
[0201] The additive K-FLEX XM4306 was added before the reduction of
the basecoat to spray viscosity.
[0202] The paint was allowed to equilibrate for 24 hours before the
final pH adjustment was made. The paint was then reduced with
deionized water before spraying to a viscosity of 25-27 seconds
using a 4 Ford Cup accordance with ASTM D 1200-99.
Preparation of Test Panels Coated with Basecoats of Examples 1 to
16
[0203] The basecoats were applied on unpolished B952 P60 pretreated
cold rolled steel panels (available from ACT Laboratories Inc.)
which had been electrocoated with ED5000 electrodeposition primer
(available from PPG Industries, Inc.) and then coated in one coat
with 1177224ER (a primer-surfacer available from PPG Industries,
Inc.) using the Sames 402 gun mounted on the Kohne machine. The
resulting basecoat had a dry film build of 0.5-0.7 mils. The
basecoats were given a five minute ambient flash and then prebaked
under the following various conditions:
[0204] The white and black basecoats of Examples 1 to 11 were baked
10 minutes at 250.degree. F. in order to simulate an overbake
condition on a commercial paint line.
[0205] The silver basecoats of Examples 12 to 16 each were baked
under the following conditions:
[0206] 1. 10 minutes at 250.degree. F. (121.degree. C.) prebake;
and
[0207] 2. 30 minutes at 250.degree. F. (121.degree. C.) followed by
application of repair base coat, and subsequent curing for 5 minute
at 200.degree. F. (93.degree. C.) prebake.
[0208] A two component clearcoat, TKU-1050AR (available from PPG
Industries, Inc.) was applied to the basecoated panels prepared as
described above. The clearcoat was applied in a two-coat
application using the same parameters as was the basecoat. The
coated panels were given a ten minute ambient flash period before
baking at 30 minutes at 250.degree. F. (121.degree. C.). The
clearcoat film build was 1.8-2.0 mils.
Testing of the White and Black Basecoats (Examples 1 to 11)
[0209] Adhesion was tested 24 hours after clearcoating using a
razor knife to cut a 6.times.6 two-millimeter grid through the
total paint coating and then taping with black TESA tape. The
adhesion was rated using ASTM D 3359-97 which assigns a whole
number percentage from 100 (no adhesion loss) to 0 (total adhesion
loss). In this case an acceptable adhesion rating was a value
ranging from 80-100. For the 10 minutes at250.degree. F.
(121.degree. C.) prebake scenario, the adhesion loss was between
clearcoat and basecoat.
20TABLE 1 Basecoat-Clearcoat Intercoat Adhesion Tests % (on resin
solids) polyether % Clearcoat Basecoat carbamate of Adhesion after
24 Basecoat Color Example A hours.sup.1 Comparative White 0 53
Example 1 Example 4 White 10 100 Example 6 White 20 85 Comparative
Black 0 0 Example 9 Example 10 Black 10 82 Example 11 Black 20
98
[0210] Table 1 shows the results of the adhesion testing of the
white and black basecoats with varying levels of the polyether
carbamate additive of Example A.
[0211] Comparative Example 1, which contains no polyether carbamate
additive,does not exhibit acceptable clearcoat to basecoat adhesion
when the basecoat undergoes an extended dehydration (10 minutes at
250.degree. F. (121.degree. C.) prebake). The addition of the
polyether carbamate additive of Example A at the 10% and 20% level
improves the adhesion to an acceptable level.
[0212] Comparative Example 9, which contains no polyether carbamate
additive, had very poor clearcoat to basecoat adhesion, the
addition of the polyether carbamate of the present invention
greatly improved the adhesion at 10% level, at 20% level it
improved even further.
Table 2--White Aqueous Basecoat Viscosity Stability
[0213]
21TABLE 2 White Aqueous Basecoat Viscosity Stability % (on resin
solids) polyether carbamate Viscosity Change Basecoat of Example A
(seconds) Comparative Example 1 0 27 Example 2 2 18 Example 3 5 16
Example 5 15 6 Example 7 30 6 Example 8 54 -4
[0214] The data presented in Table 2 shows the effect of increasing
levels of the polyether carbamate of Example A on the viscosity
stability of the white basecoat of Example 1. The #4 Ford viscosity
of the basecoat compositions was measured in accordance with ASTM
D1200-99 after which they were placed in a 140.degree. F.
(60.degree. C.) hotroom for a period of 16 hours. The basecoats
were allowed to cool and #4 Ford viscosity was remeasured. At the
15% of additive level of polyether carbamate, the viscosity
increased only 6 seconds, where the viscosity of the comparative
composition, with no polyether carbamate additive, increased 27
seconds. For the purposes of this evaluation, a viscosity increase
of greater than 15 seconds was considered to be unacceptable.
Comparative Testing of the Additive of Example A with a Commercial
Urethane Diol in the Silver Basecoat
[0215] The adhesion properties of the silver basecoats (Examples 12
through 16) was tested at 1 hour and again at 24 hours after
clearcoating. The adhesion test used a razor knife to cut a
6.times.6 two-millimeter grid through the total paint coating and
then taped with black TESA tape. The adhesion was rated using ASTM
D 3359-97, which assigns a whole number from 5 (no adhesion loss)
to 0 (total adhesion loss). In this case an acceptable adhesion
rating was a 5 or a 4. For the 10 minutes at 250.degree. F. prebake
scenario the adhesion loss was between clearcoat and basecoat. For
the 30 minutes at 250.degree. F. (121.degree. C.)/5 minutes at
250.degree. F. (121.degree. C.) prebake the adhesion loss was
between the basecoat layers.
[0216] Panels were placed into a 100% relative humidity/100.degree.
F. (38.degree. C.) environment for 240 hours, and tested within 15
minutes of removal for adhesion using the X-scribe method and
cellophane tape, according to ASTM D 3359-97. A delamination of
less than 2 mm from the scribe line passed the test, and a
delamination of greater than 2 mm was considered to be a
failure.
Table 3--Comparative Testing of the Additive of Example A and
K-FLEX XM4306 in Silver Basecoat
[0217]
22TABLE 3 Comparative Testing of the Additive of Example A and
K-FLEX XM4306 in Silver Basecoat Bake Condition A.sup.1 Bake
Condition B.sup.2 Crosshatch Crosshatch Crosshatch Crosshatch
Adhesion Adhesion Adhesion Adhesion Base 1 hr 24 hours 1 hr 24
hours GM AUTO Humidity Coat after after after after SPEC.sup.3
X-scribe Example Additive clearcoat clearcoat clearcoat clearcoat
Appearance adhesion 12* None 0 0 0 0 65.2 Pass 13 7% rs Additive of
5 5 0 5 70.0 Pass Example A 14 15% rs 5 5 5 5 63.6 Pass Additive of
Example A 15* 7% rs 0 0 0 0 62.5 Fail K-FLEX XM4306 Competitive
Additive 16* 15% rs 5 5 0 5 58.7 Fail K-FLEX XM4306 Competitive
Additive *Examples 12, 15, and 16 are Comparative Examples
.sup.1Basecoat baked 10 minutes at 250 .degree. F. (121.degree.
C.). Then clearcoat applied. .sup.2Basecoat baked 30 minutes at 250
.degree. F. (121.degree. C.). Then additional coat of basecoat
applied and panel baked 5 minutes at 200.degree. F. (93.degree.
C.). Then clearcoat applied. .sup.3Higher numbers indicate better
appearance.
[0218] As is shown in Table 3, Comparative Example 12, the silver
basecoat with no additive, does not exhibit acceptable crosshatch
adhesion under either basecoat bake condition. Addition of 7% on
resin solids of the polyether carbamate additive of the present
invention, Example A, gives excellent crosshatch adhesion under
both bake conditions when tested 24 hours after clearcoat
application, and under Bake Condition A when tested both 1 hour and
24 hours after clearcoat application. By contrast, a 7% on resin
solids addition of the competitive urethanediol additive, K-FLEX
XM4306, fails to show any crosshatch adhesion improvement under
either bake condition.
[0219] When the additive level of the polyether carbamate additive
of the present invention is increased to 15% on resin solids, the
crosshatch adhesion is excellent under both basecoat and both
clearcoat conditions. At level of the competitive urethanediol
additive, however, the basecoat fails crosshatch adhesion under
Bake Condition B when tested one hour after clearcoat
application.
[0220] A further advantage of the polyether carbamate additive of
the present IS invention over the competitive urethanediol additive
is that addition of the competitive urethanediol additive
negatively impacts humidity resistance of the basecoat. As can be
seen in Table 3, addition of the competitive urethanediol additive
at either the 7% on resin solids or 15% on resin solids levels
causes the basecoat to fail X-scribe adhesion after humidity. By
contrast, the polyether carbamate additive of the present invention
does not adversely affect the humidity resistance of the basecoat
at either the 7% or the 15% on resin solids level, Also, as can be
seen in Table 3 the appearance of the basecoats with the additive
of the present invention was better than that of the basecoats with
the competitive urethanediol additive.
[0221] It will be appreciated by those in the art that changes
could be made to the embodiments described above without departing
from the broad inventive concept thereof. It is understood,
therefore, that this invention is not limited to the particular
embodiments disclosed, but it is intended to cover modifications
which are within the spirit and scope of the invention, as defined
by the appended claims.
* * * * *