U.S. patent application number 10/545828 was filed with the patent office on 2006-06-29 for polytrimethylene ether diol containing coating compositions.
Invention is credited to Joseph V. Kurian, James William Oneil, Patricia Mary Ellen Sormani, Hari Babu Sunkara.
Application Number | 20060142473 10/545828 |
Document ID | / |
Family ID | 33098152 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060142473 |
Kind Code |
A1 |
Sunkara; Hari Babu ; et
al. |
June 29, 2006 |
Polytrimethylene ether diol containing coating compositions
Abstract
A coating composition comprising a film forming binder of a. at
least one polymer that has pendant groups, such as, hydroxyl,
carboxyl, glycidyl, amine, amide, silane and mixtures thereof that
are reactive with a crosslinking component and the polymer has a
glass transition temperature (Tg) of 10 to 80.degree. C.; b. a
polytrimethylene ether diol having a Mn (number average molecular
weight) of 500 to 5,000; and c. a crosslinking component, such as,
organic polyisocyanates, melamine formaldehydes, alkylated melamine
formaldehydes, benzoquanamine formaldehyde, urea formaldehyde,
polyepoxides, silane resin and any mixtures thereof; wherein the
coating composition can be used as a clear coating composition and
can contain pigments and may be used as a pigmented top coating, a
pigmented base coating, a primer or primer surfacer coating and is
useful for coating automobile and truck bodies and parts,
industrial equipment, appliances and exterior structures.
Inventors: |
Sunkara; Hari Babu;
(Hockessin, DE) ; Sormani; Patricia Mary Ellen;
(Newark, DE) ; Oneil; James William; (Chadds Ford,
PA) ; Kurian; Joseph V.; (Hockessin, DE) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
33098152 |
Appl. No.: |
10/545828 |
Filed: |
March 19, 2004 |
PCT Filed: |
March 19, 2004 |
PCT NO: |
PCT/US04/08644 |
371 Date: |
August 17, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60456756 |
Mar 21, 2003 |
|
|
|
Current U.S.
Class: |
524/589 ;
428/422.8 |
Current CPC
Class: |
Y10T 428/31605 20150401;
C09D 169/00 20130101; C08G 18/792 20130101; C08L 33/14 20130101;
Y10T 428/20 20150115; C09D 175/04 20130101; Y10T 428/31873
20150401; Y10T 428/31547 20150401; C08G 18/4063 20130101; Y10T
428/31663 20150401; Y10T 428/31551 20150401; C08L 33/24 20130101;
C08L 33/06 20130101; C09D 133/066 20130101; C08L 33/14 20130101;
Y10T 428/31692 20150401; C08L 2666/14 20130101; C08L 2666/14
20130101; C08L 2666/14 20130101; C08L 2666/16 20130101; C08L
2666/14 20130101; C09D 133/066 20130101; C08L 2666/14 20130101;
C09D 167/00 20130101; C08G 18/4825 20130101; C08L 33/24 20130101;
Y10T 428/31504 20150401; C09D 167/00 20130101; C08L 33/06 20130101;
C08K 5/0025 20130101; C08L 71/02 20130101; C09D 169/00
20130101 |
Class at
Publication: |
524/589 ;
428/422.8 |
International
Class: |
C08G 18/08 20060101
C08G018/08; B32B 27/00 20060101 B32B027/00 |
Claims
1. A coating composition comprising a film forming binder
comprising a. at least one polymer having pendant groups selected
from the group consisting of hydroxyl, carboxyl, glycidyl, amine,
amide, silane and mixtures thereof and having a glass transition
temperature (Tg) of 10 to -80.degree. C. and wherein the pendant
groups are reactive with the crosslinking agent c.; b. a
polytrimethylene ether diol having a Mn (number average molecular
weight) of 500 to 5,000; and c. a crosslinking component selected
from the group consisting of organic polyisocyanates, melamine
formaldehydes, alkylated melamine formaldehydes, benzoquanamine
formaldehyde, urea formaldehyde, polyepoxides, silane resins and
any mixtures thereof.
2. The coating composition of claim 1 wherein the polytrimethylene
ether diol has a Mn 1,000 to 3,000, a Tg of approximately
-75.degree. C. and a hydroxyl number of 20 to 200.
3. The coating composition of claim 1 wherein the binder comprises;
a. 10 to 80% by weight of at least on polymer having pendant
reactive groups, b. 1 to 50% by weight of polytrimethylene ether
diol, c. 10 to 50% by weight of the crosslinking agent; wherein the
percentages are based on the weight of the binder and the sum of
the percentages of a., b. and c. is 100%.
4. The coating composition of claim 3 wherein the polymer having
reactive groups is an acrylic polymer wherein the reactive groups
are selected from the group consisting of hydroxyl groups, carboxyl
groups, glycidyl groups, amino groups, silane groups and any
mixtures thereof.
5. The coating composition of claim 4 wherein the acrylic polymer
has a weight average molecular weight of 5,000-50,000 and a Tg of
10.degree. C. to 80.degree. C. and consists essentially of
polymerized monomers selected from the group consisting of linear
alkyl (meth)acrylates having 1-12 carbon atoms in the alkyl group,
cyclic or branched alkyl (meth)acrylates having 3-12 carbon atoms
in the alkyl group, isobornyl (meth)acrylate, styrene, alpha methyl
styrene, (meth)acrylonitrile, (meth)acryl amides, and polymerized
monomers that provide groups reactive with isocyanate selected from
the group consisting of hydroxy alkyl (meth)acrylates having 1 to 4
carbon atoms in the alkyl group, glycidyl (meth)acrylates, hydroxy
amino alkyl(meth)acrylates having 1 to 4 carbon atoms in the alkyl
group, alkoxy silyl alkyl (meth)acrylates and (meth)acrylic
acid.
6. The coating composition of claim 5 wherein the acrylic polymer
has a hydroxyl equivalent weight of 300 to 800 and consists
essentially of polymerized monomers selected from the group
consisting of alkyl (meth)acrylates having 1 to 12 carbon atoms in
the alkyl group, isobomyl methacrylate styrene, alpha methyl
styrene, (meth)acrylonitrile, (meth)acryl am ides and mixtures
thereof, and polymerized monomers consisting essentially of hydroxy
alkyl (meth)acrylates having 1 to 4 carbon atoms in the alkyl
group.
7. The coating composition of claim 6 wherein the acrylic polymer
consists essentially of styrene, ethylhexyl methacrylate, isobornyl
methacrylate and hydroxyethyl (meth)acrylate.
8. The coating composition of claim 3 wherein the crosslinking
agent is an organic polyisocyanate selected from the group
consisting of aliphatic polyisocyanates, cycloaliphatic
polyisocyanates, aromatic polyisocyanates, trifunctional
isocyanates and isocyanate adducts.
9. The coating composition of claim 3 in which the polyisocyanate
is selected from the group consisting of isophorone diisocyanate,
toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane
diisocyanate, triphenyl triisocyanate, benzene triisocyanate,
toluene triisocyanate and the trimer of hexamethylene
diisocyanate.
10. The coating composition of claim 1 in which the polymer having
pendant groups is a polyester having pendant groups selected from
the group consisting of hydroxyl groups, carboxyl groups and
mixtures thereof.
11. The coating composition of claim 1 in which the polymer having
pendant groups is a polyesterurethane having pendant groups
selected from the group consisting of hydroxyl groups, carboxyl
groups and mixtures thereof.
12. The coating composition of claim 1 in which the polymer having
pendant groups is a polyepoxy resin having pendant hydroxyl groups
and epoxide groups.
13. The coating composition of claim 1 in which the polymer having
pendant groups is polyetherurethane having pendant groups selected
from the group consisting of hydroxyl groups, carboxyl groups and
mixtures thereof.
14. The coating composition of claim 1 in which the polymer having
pendant groups is a poly(meth)acrylamide.
15. The coating composition of claim 1 in which the polymer having
pendant groups is a polyacrylourethane having pendant groups
selected from the group consisting of hydroxyl groups, carboxyl
groups and mixtures thereof.
16. The coating composition of claim 1 in which the polymer having
pendant groups is a polycarbonate.
17. The coating composition of claim 3 containing an
aminofunctional silane crosslinking agent having the formula
(X.sub.nR).sub.aSi--(--OSi).sub.y(OR.sup.3).sub.b wherein X is
selected from the group consisting of --NH.sub.2, --NHR.sup.4, and
SH, n is an integer from 1 to 5, R is a hydrocarbon group contain 1
to 22 carbon atoms, R.sup.3is an alkyl group containing 1 to 8
carbon atoms, a is at least 1, y is from 0 to 20, b is at least 2
and R.sup.4 is an alkyl group having 1 to 4 carbon atoms.
18. The coating composition of claim 17 containing an at least one
additional amino functional compound selected from the group
consisting of primary amines, secondary amines and tertiary
amines.
19. The coating composition of claim 17 wherein the aminofunctional
silane is selected from the group consisting of
N-beta-(aminoethyl)-gamma-aminopropyl trimethoxy silane and
diethylene triamino propylaminotrimethoxy silane.
20. The coating composition of claim 3 in which the crosslinking
agent comprises melamine formaldehyde.
21. The coating composition of claim 3 in which the crosslinking
agent comprise an alkylated melamine formaldehyde.
22. The coating composition of claim 3 in which the crosslinking
agent comprise a benzoquanamine formaldehyde.
23. The coating composition of claim 3 in which the crosslinking
agent comprise an urea formaldehyde.
24. The coating composition of claim 3 in which the crosslinking
agent comprises a polyepoxide.
25. The coating composition of claim 3 in which the crosslinking
agent comprises a silane resin.
26. The coating composition of claim 1 containing pigments in a
pigment to binder weight ratio of 1/100 to 350/100.
27. The coating composition of claim 1 comprising in addition to
the polytrimethylene ether diol, a branched or linear oligomer.
28. The coating composition of claim 1 wherein the polytrimethylene
ether diol is formed via a bio conversion process.
29. A two component coating composition comprising Component A of a
polymer having pendant groups that are reactive with isocyanate
moieties and having a glass transition temperature (Tg) of 10 to
80.degree. C.; and a polytrimethylene ether diol having a Mn
(number average molecular weight) of 500 to 5,000; and Component B
an organic polyisocyanate crosslinking agent; wherein Components A
and B are thoroughly mixed together before application to a
substrate.
30. A coating composition comprising a film forming binder of a. at
least one polymer having pendant groups selected from the group
consisting of hydroxyl, carboxyl, glycidyl, amine, amide, silane
and mixtures thereof and having a glass transition temperature (Tg)
of 10 to 80.degree. C. and wherein the pendant groups are reactive
with the crosslinking agent c.; b. a copolymer of polytrimethylene
ether diol having a Mn (number average molecular weight) of 500 to
5,000 comprising at least 50% by weight, based on the weight of the
diol of polymerized 1,3-propanediol and up to 50% by weight, based
on the weight of the diol of another polymerized alkane diol; and
c. a crosslinking component selected from the group consisting of
organic polyisocyanates, melamine formaldehydes, alkylated melamine
formaldehydes, benzoquanamine formaldehyde, urea formaldehyde,
polyepoxides, silane resins and any mixtures thereof.
31. The coating composition of claim 30 containing up to 60% by
weight of solvent.
32. The coating composition of claim 30 wherein the copolymer of
polytrimethylene ether diol has a Mn 1,000 to 3,000, a Tg of
approximately -75.degree. C. and a hydroxyl number of 20 to
200.
33. The coating composition of claim 30 wherein the copolymer of
polytrimethylene ether diol is a blend of high and low molecular
weight ether diols wherein the high molecular weight diol has an Mn
of 1,000 to 4,000 and the low molecular weight diol has an Mn of
150 to 500 and the average Mn of the blend is 1,000 to 3,000.
34. The coating composition of claim 30 wherein the polymer having
pendant groups has a weight average molecular weight of 5,000 to
50,000 and a Tg of 30.degree. C. to 80.degree. C. and consists of
an acrylic polymer consisting essentially of polymerized monomers
selected from the group consisting of linear alkyl (meth)acrylates
having 1 to 12 carbon atoms in the alkyl group, cyclic or branched
alkyl (meth)acrylates having 3 to 12 carbon atoms in the alkyl
group, isobomyl (meth)acrylate, styrene, alpha methyl styrene,
(meth)acrylonitrile, (meth)acryl amides, and polymerized monomers
that provide groups reactive with isocyanate selected from the
group consisting of hydroxy alkyl (meth)acrylates having 1 to 4
carbon atoms in the alkyl group, glycidyl (meth)acrylates, hydroxy
amino alkyl(meth)acrylates having 1 to 4 carbon atoms in the alkyl
group, alkoxy silyl alkyl (meth)acrylate and (meth)acrylic
acid.
35. The coating composition of claim 34 wherein the acrylic polymer
has a hydroxyl equivalent weight of 300 to 800 and consists
essentially of polymerized monomers selected from the group
consisting of alkyl (meth)acrylates having 1 to 12 carbon atoms in
the alkyl group, isobornyl methacrylate styrene, alpha methyl
styrene, (meth)acrylonitrile, (meth)acryl amides, and polymerized
monomers consisting of hydroxy alkyl (meth)acrylates having 1 to 4
carbon atoms in the alkyl group.
36. The coating composition of claim 35 wherein the acrylic polymer
consists essentially of styrene, ethylhexyl methacrylate, isobornyl
methacrylate and hydroxyethyl (meth)acrylate.
37. The coating composition of claim 30 wherein the crosslinking
component comprises a polyisocyanate selected from the group
consisting of aliphatic polyisocyanates, cycloaliphatic
polyisocyanates, aromatic polyisocyanates, trifunctional
isocyanates and isocyanate adducts.
38. The coating composition of claim 30 containing pigmen's in a
pigment to binder weight ratio of 1/100 to 300/100.
39. A coating composition comprising a binder comprising about 40
to 90% by weight, based on the weight of the binder, of
polytrimethylene ether diol having a Mn (number average molecular
weight) of 500 to 5,000 and 10 to 60% by weight, based on the
weight of the binder, of an organic polyisocyanate crosslinking
agent.
40. A coated substrate which comprises a substrate coated with a
layer of the coating composition of claim 1.
41. The coated substrate of claim 40 wherein the substrate is
selected from the group consisting of steel and aluminum.
42. The coated substrate of claim 40 comprising a top coating
selected from the group consisting of a clear coat/pigmented base
coat and a pigmented topcoat.
43. A process which comprises applying a first layer of the
composition of claim 1 to a substrate and drying said layer and
applying at least on additional layer of a coating composition to
the first layer and curing the layers.
44. The process of claim 43 wherein the at least one additional
layer comprises a pigmented color coat and a clear coat.
45. A process which comprises applying a first layer of the
composition of claim 30 to a substrate and drying said layer and
applying at least on additional layer of a coating composition to
the first layer and curing the layers.
46. The process of claim 45 wherein the at least one additional
layer comprises a pigmented color coat and a clear coat.
47. A process for refinishing a damaged coating on a motor vehicle
body which comprises applying a layer of the pigmented coating
composition of claim 2 to damaged coating and at least partially
curing the layer and then applying a second layer of a pigmented
top coat or a layer of a pigmented base coat and a layer of a clear
coat and curing all of the layers to form a finish.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention is directed to coating compositions, in
particular, to coating composition useful as interior and exterior
top coats, base coats, primers, primer surfacers and primer fillers
having excellent physical properties, such as, flexibility,
hardness, chip resistance and when used as a primer, a primer
surfacer or a primer filler also has a combination of excellent
sandability and chip resistance.
[0003] 2. Description of the Prior Art
[0004] Finishes used in the manufacture, repair and refinish of
automobile and truck bodies and parts, industrial equipment,
appliances and the like must provide a high quality appearance and
have excellent physical properties to withstand long term use,
particularly when exposed to weathering. Many finishes now in use
are multi-layered finishes and each layer has different
requirements. For example, the multi-layer finishes on automobile
and truck bodies and parts typically utilize the following: (1) an
electrocoat layer applied over a substrate, typically, a
phosphatized cold rolled steel, (2) a primer layer, (3) a colored
layer, typically pigmented, and (4) a clear layer. A colored top
coat layer may be used in place of the colored layer and clear
layer. On repairing or refinishing such multi-layer finishes, a
suitable primer, primer surfacer or primer filler coating is
applied over the multi-layer finish that usually is sanded thereby
exposing one or more layers or is applied over a filler material
that has been used to fill in surface imperfections.
[0005] This primer, primer surfacer or primer filler, herein after,
"prime", has many requirements. It must have adhesion to the
substrate and provide a surface to which the colored layer or top
coat will adhere. It must be readily sandable in a reasonably short
period of time after application, for example, about three hours
after application. It must provide the resulting multi-layer finish
with good impact resistance, in particular, stone chip
resistance.
[0006] Coatings used to form finishes on appliances, flexible and
rigid thermoset or thermoplastic substrates, industrial equipment,
exterior structures, and the like may be applied directly to the
substrate which may be untreated, primed or surface treated. The
resulting finish must have the required properties for its intended
use.
[0007] It would be desirable to have a basic coating composition
that can be formulated to meet the physical demands of these wide
varieties of end uses. The novel composition of this invention can
be readily formulated using conventional techniques to form
finishes that have the required physical properties that meet
typical end use requirements for the above applications. Also, it
would be desirable that such a composition contains components that
are derived from renewable resources. The novel composition of this
invention meets these aforementioned requirements.
SUMMARY OF THE INVENTION
[0008] A coating composition comprising a film forming binder of
[0009] a. at least one polymer that has pendant groups, such as,
hydroxyl, carboxyl, glycidyl, amine, amide, silane and mixtures
thereof that are reactive with a crosslinking component and the
polymer has a glass transition temperature (Tg) of 10 to 80.degree.
C.; [0010] b. a polytrimethylene ether diol having a Mn (number
average molecular weight) of 500 to 5,000; and [0011] c. a
crosslinking component, such as, organic polyisocyanates, melamine
formaldehydes, alkylated melamine formaldehydes, benzoquanamine
formaldehyde, urea formaldehyde, polyepoxides, silane resins and
any mixtures thereof;
[0012] wherein the coating composition can be used as a clear
coating composition, can contain pigments and be used as a
pigmented top coating, a pigmented base coating, a primer, primer
filler, or primer surfacer coating and is useful for coating, for
example, automobile and truck bodies and parts, industrial
equipment, appliances, and interior and exterior structures.
[0013] DETAILED DESCRIPTION OF THE INVENTION
[0014] The novel coating composition of this invention preferably
is a solvent-borne coating composition containing a film forming
binder of at least one polymer that has pendant groups, such as,
hydroxyl, carboxyl glycidyl, amine, amide, silane or mixtures of
these groups that are reactive with a crosslinking component
utilized in the composition and the polymer has a glass transition
temperature (Tg) of 10 to 80.degree. C. The binder contains a
polytrimethylene ether diol having a Mn (number average molecular
weight) of 500 to 5,000; and also, a crosslinking component and
optionally, the composition can contain pigment(s).
[0015] The coating composition can be used as a clear coating
composition in combination with a pigmented base coat or color
coat, which optionally, also may be the novel composition or
another composition. The composition can be pigmented and used as a
top coating, primer coating, primer surfacer, primer filler coating
and the like. The coating composition is particularly useful for
coating automobile and truck bodies and parts but can also be used
for appliances, industrial equipment, home use items, such as,
shelves, cabinets and various furniture items and can be used on a
variety of rigid and flexible thermoset and thermoplastic
substrates and composite substrates and can be used as an
architectural paint for the interior and exterior of homes, office
buildings, industrial buildings and the like.
[0016] These substrates, over-which the coating composition, may be
applied may be untreated, treated, primed and the like to improve
adhesion. Typical substrates include aluminum, magnesium, copper,
tin, zinc, galvanized steel, stainless steel, alloys of steel, cold
rolled steel, phosphatized cold rolled steel, phosphatized cold
rolled steel having an electrodeposited primer thereon, plastics,
such as, polypropylene and copolymers thereof, polyurethanes,
polycarbonate, ABS, plastic fiber reinforced substrates, such as
RIM, SMC (sheet molding compound) and the like.
[0017] One particularly useful coating composition is a primer that
is used for refinishing or repairing automobile and truck bodies or
parts. This primer has a particular advantage that after a
relatively short time after application, it is sufficiently cured
and can be sanded. This primer in combination with a topcoat of a
color coat and clear coat or a pigmented mono-coat provides a
finish that has improved chip resistance.
[0018] The term "binder" as used herein refers to the film forming
constituents of the composition that include the polymer having
reactive groups, polytrimethylene ether diol, and the crosslinking
component and any other polymers, reactive oligomers and/or
reactive diluents. Solvents, pigments, catalysts, rheology
modifiers, antioxidants, UV stabilizers, leveling agents,
antifoaming agents, anti-cratering agents, adhesion promoting
agents are not included in the term.
[0019] The binder of the novel coating composition typically
contains (a) 10 to 80% by weight, preferably, 20 to 70% by weight,
of the polymer(s) having pendant reactive groups, (b) 1 to 50% by
weight, preferably 5 to 40% by weight of polytrimethylene ether
diol, and (c) 10 to 50% by weight, preferably 15 to 45% by weight
of the crosslinking component. All weight percentages are based on
the total weight of the binder of the coating composition and the
sum of the percentages of (a), (b) and (c) is 100%
[0020] The polymer used in the composition has a weight average
molecular weight of about 1,000 to 100,000, a Tg of 10 to
80.degree. C. and contains reactive moieties, such as, hydroxyl,
carboxyl, glycidyl, amine, amide, silane or mixtures of such
groups. The Tg of the binder when cured is greater than 30.degree.
C. Theses polymers.can be straight chain polymers, branched
polymers, graft copolymers, graft terpolymers and core shell
polymers. Typical of these polymers are acrylic polymers,
acrylourethane polymers, polyesters, polyesterurethanes,
polyetherurethanes, poly(meth)acrylamides, polyepoxides and
polycarbonates.
[0021] Preferably, acrylic polymers are used having a weight
average molecular weight of 5,000 to 50,000 and more preferably, of
10,000 to 25,000 and a Tg preferably, of 30.degree. C. to
80.degree. C. In general, typically useful acrylic polymers are
those known in the art and are polymers of the following: linear
alkyl (meth)acrylates having 1 to 12 carbon atoms in the alkyl
group, cyclic or branched alkyl (meth)acrylates having 3 to 12
carbon atoms in the alkyl group, including isobomyl (meth)acrylate,
and the polymer can contain styrene, alpha methyl styrene, vinyl
toluene, and (meth)acrylonitrile, (meth)acryl amides and monomers
that provide pendant reactive groups like, hydroxy alkyl
(meth)acrylates having 1 to 6 carbon atoms in the alkyl group,
glycidyl (meth)acrylate, hydroxy amino alkyl (meth)acrylate having
1 to 4 carbon atoms in the alkyl group, alpha beta ethylenically
unsaturated carboxylic acids like, (meth)acrylic acid, silane
monomers, like alkoxy silyl alkyl (meth)acrylates, such as,
trimethoxysilylpropyl (meth)acrylate, silane (meth)acrylate, vinyl
trimethoxy silane and the like.
[0022] Preferred are hydroxy functional acrylic polymers having a
hydroxy equivalent weight (on a solids basis) of 300 to 800,
preferably, 380 to 750 and more preferably, 450 to 580 and are
polymers of hydroxy alkyl (meth)acrylates and one or more of the
aforementioned monomers. The hydroxyl equivalent weight is the
grams of resin per equivalent of hydroxyl groups. One preferred
hydroxy containing acrylic polymer contains 35 to 40% by weight
styrene, 15 to 25% by weight ethylhexyl methacrylate and 15 to 20%
by weight isobornyl methacrylate and 20 to 30% by weight
hydroxyethyl methacrylate. A particularly preferred acrylic polymer
contains 37% styrene, 20% by weight 2-ethylhexyl methacrylate and
17.5% by weight isobornyl methacrylate and 25.5% by weight
hydroxyethyl methacrylate
[0023] Suitable hydroxyl-functional unsaturated monomers that are
used to introduce hydroxyl groups into the acrylic polymer are, for
example, hydroxyalkyl esters of alpha,beta-olefinically unsaturated
monocarboxylic acids with primary or secondary hydroxyl groups.
These may, for example, comprise the hydroxyalkyl esters of acrylic
acid, methacrylic acid, crotonic acid and/or isocrotonic acid. The
hydroxyalkyl esters of (meth)acrylic acid are preferred. Examples
of suitable hydroxyalkyl esters of alpha, beta-olefinically
unsaturated monocarboxylic acids with primary hydroxyl groups are
hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate,
hydroxybutyl (meth)acrylate, hydroxyamyl (meth)acrylate,
hydroxyhexyl (meth)acrylate. Examples of suitable hydroxyalkyl
esters with secondary hydroxyl groups are 2-hydroxypropyl
(meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl
(meth)acrylate.
[0024] Additional useful hydroxy-functional unsaturated monomers
are reaction products of alpha,beta-unsaturated monocarboxylic
acids with glycidyl esters of saturated monocarboxylic acids
branched in alpha position, for example with glycidyl esters of
saturated alpha-alkylalkanemonocarboxylic acids or
alpha,alpha'-dialkylalkanemonocarboxylic acids. These preferably
comprise the reaction products of (meth)acrylic acid with glycidyl
esters of saturated alpha,alpha-dialkylalkanemonocarboxylic acids
with 7 to 13 carbon atoms per molecule, particularly preferably
with 9 to 11 carbon atoms per molecule. These reaction products may
be formed before, during or after the copolymerization
reaction.
[0025] Further usable hydroxy-functional unsaturated monomers are
reaction products of hydroxyalkyl (meth)acrylates with lactones.
Hydroxyalkyl (meth)acrylates which may be used are, for example,
those stated above. Suitable lactones are, for example, those that
have 3 to 15 carbon atoms in the ring, wherein the rings may also
comprise different substituents. Preferred lactones are
gamma-butyrolactone, delta-valerolactone, epsilon-caprolactone,
beta-hydroxy-beta-methyl-delta-valerolactone, lambda-laurolactone
or mixtures thereof. Epsilon-caprolactone is particularly
preferred. The reaction products preferably comprise those prepared
from 1 mole of a hydroxyalkyl ester of an alpha,beta-unsaturated
monocarboxylic acid and 1 to 5 moles, preferably on average 2
moles, of a lactone. The hydroxyl groups of the hydroxyalkyl esters
may be modified with the lactone before, during or after the
copolymerization reaction.
[0026] Suitable unsaturated monomers that can be used to provide
the acrylic polymer with carboxyl groups are, for example,
olefinically unsaturated monocarboxylic acids, such as, for
example, acrylic acid, methacrylic acid, crotonic acid, isocrotonic
acid, itaconic acid. Acrylic acid and methacrylic acid are
preferably used.
[0027] Suitable unsaturated monomers that can be used to provide
the acrylic polymer with glycidyl groups are, for example, allyl
glycidyl ether, 3,4-epoxy-1-vinylcyclohexane, epoxycyclohexyl
(meth)acrylate, vinyl glycidyl ether and glycidyl (meth)acrylate.
Glycidyl (meth)acrylate is preferably used.
[0028] Free-radically polymerizable, olefinically unsaturated
monomers which, apart from at least one olefinic double bond, do
not contain additional functional groups that can be used to form
the acrylic polymer are, for example, esters of unsaturated
carboxylic acids with aliphatic monohydric branched or unbranched
as well as cyclic alcohols with 1 to 20 carbon atoms. The
unsaturated carboxylic acids, which may be considered, are acrylic
acid, methacrylic acid, crotonic acid and isocrotonic acid. Esters
of (meth)acrylic acid are preferred. Examples of (meth)acrylic acid
esters are methyl acrylate, ethyl acrylate, isopropyl acrylate,
tert.-butyl acrylate, n-butyl acrylate, isobutyl acrylate,
2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate and the
corresponding methacrylates. Examples of (meth)acrylic acid esters
with cyclic alcohols are cyclohexyl acrylate, trimethylcyclohexyl
acrylate, 4-tert.-butylcyclohexyl acrylate, isobomyl acrylate and
the corresponding methacrylates.
[0029] Further useful unsaturated monomers that do not contain
additional functional groups are, for example, vinyl ethers, such
as, isobutyl vinyl ether and vinyl esters, such as, vinyl acetate,
vinyl propionate, vinyl aromatic hydrocarbons, preferably those
with 8 to 9 carbon atoms per molecule. Examples of such monomers
are styrene, alpha-methylstyrene, chlorostyrenes,
2,5-dimethylstyrene, p-methoxystyrene, vinyl toluene. Styrene is
preferably used.
[0030] Small proportions of olefinically polyunsaturated monomers
may also be used. These are monomers having at least 2
free-radically polymerizable double bonds per molecule. Examples of
these are divinylbenzene, 1,4-butanediol diacrylate, 1,6-hexanediol
diacrylate, neopentyl glycol dimethacrylate, glycerol
dimethacrylate.
[0031] The hydroxy-functional (meth)acrylic polymers generally are
formed by free-radical copolymerization using conventional
processes well known to those skilled in the art, for example,
bulk, solution or bead polymerization, in particular by
free-radical solution polymerization using free-radical
initiators.
[0032] Acrylourethanes also can be used to form the novel coating
composition of this invention. Typical useful acrylourethanes are
formed by reacting the aforementioned acrylic polymers with an
organic polyisocyanate. Generally, an excess of the acrylic polymer
is used so that the resulting acrylourethane has terminal acrylic
segments having reactive groups as described above. These
acrylourethanes can have reactive end groups and/or pendant groups
such as hydroxyl, carboxyl, amine, glycidyl, amide, silane or
mixtures of such groups. Useful organic polyisocyanates are
described hereinafter as the crosslinking component but also can be
used to form acrylourethanes useful in this invention. Typically
useful acrylourethanes are disclosed in Stamegna et al. U.S. Pat.
No. 4,659,780, which is hereby incorporated by reference.
[0033] Hydroxy containing polyesters can be used to form the novel
coating composition of this invention. Typical polyesters that can
be used have an acid value of 15 to 60, a hydroxyl value of not
more than 95 and have a number average molecular weight from 1500
to 10,000. The polyesters may be saturated or unsaturated and
optionally, may be modified with fatty acids. These polyesters are
the esterification product of one or more polyhydric alcohols, such
as, alkylene diols and glycols; monocarboxylic acids and a
polycarboxylic acids or anhydrides thereof, such as, dicarboxylic
and/or tricarboxylic acids or tricarboxylic acid anhydrides.
[0034] Examples of polyhydric alcohols used to form the polyester
include triols and tetraols, such as, trimethylol propane,
triethylol propane, trimethylol ethane, glycerine, and dihydric
alcohols and diols that include ethylene glycol, propylene glycol,
1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, diethylene glycol,
dipropylene glycol, 1,4-cyclohexane dimethanol, hydrogenated
bisphenols A and F, Esterdiol 204 (Trademark of Union Carbide) and
highly functional polyols, such as, trimethylolethane,
trimethylolpropane, and pentaerythritol. Polyhydric alcohols having
carboxyl groups may be used, such as, dimethylol propionic acid
(DMPA).
[0035] Typical acids and anhydrides that can be used to form the
polyester are aliphatic or aromatic carboxylic acids and anhydrides
thereof, such as, adipic acid, azelaic acid, sebacic acid,
dimerized fatty acids, maleic acid, maleic anhydride, succinic
acid, succinic anhydride, isophthalic acid, terephthalic acid,
phthalic acid, phthalic anhydride, dimethyl terephthalic acid,
naphthalene dicarboxylic acid, tetrahydro- and hexahydrophthalic
anhydride, tetrachlorophthalic acid, terephthalic acid bisglycol
ester, benzophenone dicarboxylic acid, trimellitic acid and
trimellitic anhydride.
[0036] One useful polyester is the estrification product of
neopentyl glycol, trimethylol propane, 1,6 hexane diol, adipic
acid, isophthalic acid and trimellitic anhydride.
[0037] Polyesterurethanes also can be used to form the novel
coating composition of this invention. Typically useful
polyesterurethanes are formed by reacting the aforementioned
polyesters with an organic polyisocyanate. Generally, an excess of
the polyester is used so that the resulting polyesterurethane has
terminal polyester segments having reactive hydroxyl groups.
Carboxy functional polyesterurethanes can also be used. Useful
organic polyisocyanates are described hereinafter as the
crosslinking component but can be used to form polyesterurethanes
useful in this invention. Typically useful coating compositions
that utilize polyesterurethanes are disclosed in Johnson U.S. Pat.
No. 5,122,522, which is hereby incorporated by reference.
[0038] Polycarbonate polyols can be used as to form the novel
coating composition and are the esters of carbonic acid which are
obtained by the reaction of carbonic acid derivatives, e.g.,
diphenyl carbonate or phosgene with polyols, preferably diols.
Suitable diols are any of those mentioned above.
[0039] Polyetherurethanes can be used to form the novel coating
composition and are the reaction product of a polyetherpolyol
and/or polylactonepolyol and an organic polyisocyanate. Suitable
polyetherpolyols are, for example, polyetherpolyols of the
following general formula: H[--O--(CHR.sup.1).sub.n].sub.mOH in
which R.sup.1 represent hydrogen or a lower alkyl group, for
example, having 1-6 carbon atoms, and n=2 to 6 and m=10 to 50. The
R.sup.1 groups may be identical or different. Examples of
polyetherpolyols are poly(oxypropylene) glycols, poly(oxymethylene)
glycols, poly(oxyethylene) glycols, or mixtures thereof, block
copolymers that contain different glycols or mixed block copolymers
that contain different oxytetramethylene, oxyethylene and/or
oxypropylene units.
[0040] Polylactone polyols that can be used to form a useful
polyetherurethane are polyols that are derived from lactones,
preferably caprolactones and can be obtained, for example, by
reacting epsilon caprolactone with a diol. Diols that can be used
to react with lactones are, for example, ethylene glycol,
1,3-propanediol, 1,4-butanediol and dimethylolcyclohexane.
[0041] Typically useful polyepoxides that can be used to form the
novel coating composition are poly epoxy hydroxy ether resins
having 1,2-epoxy equivalency of about two or more, that is,
polyepoxides that have on an average basis two or more epoxy groups
per molecule. Preferred polyepoxides are polyglycidyl ethers of
cyclic polyols. Particularly preferred are polyglycidyl ethers of
ployhydric phenols, such as, bisphenol A or bisphenol F. Such
polyepoxides can be produced by the etherification of polyhydric
phenols with epihalohydrin or dihalohydrin, such as,
epichlorohydrin or dichlorohydrin in the presence of alkali.
Examples of useful polyhydric phenols are
2,bis-(4-hydroxyphenyl)ethane,
2-methyl-1,1-bis-(4-hydroxyphenyl)propane and the like. Besides
polyhydric phenols, other cyclic polyols can be used to prepare the
polyglycidyl ethers, such as, alicyclic phenols, particularly,
cycloaliphatic polyols, and hydrogenated bisphenol A.
[0042] Polyepoxides can be chain extended with polyether or
polyester polyols, such as, polycaprolactone diols and with
ethoxylated bisphenol A.
[0043] Poly(meth)acrylamides can be used to form the novel coating
composition, such as, polymers of (meth)acrylamide and alkyl
(meth)acrylates, hydroxy alkyl (meth)acrylates, (meth)acrylic acid
and or one of the aforementioned ethylenically unsaturated
polymerizable monomers.
[0044] The polytrimethylene ether diol used in the coating
composition has a number average molecular weight (Mn) in the range
of 500 to 5,000, preferably 1,000 to 3,000. The polytrimethylene
ether diol has a Tg of about -75.degree. C., a polydispersity in
the range of 1.1 to 2.1 and a hydroxyl number in the range of 20 to
200.
[0045] The polytrimethylene ether diol is prepared by an
acid-catalyzed polycondensation of 1,3-propanediol, preferably, as
described in US. Published Patent Application Numbers 2002/7043 A1
and 2002/10374 A1, both of which are hereby incorporated by
reference. The polytrimethylene ether diol also can be prepared by
a ring opening polymerization of a cyclic ether, oxetane, as
described in J. Polymer Sci., Polymer Chemistry Ed. 28, 449 to 444
(1985) which is also incorporated by reference. The
polycondensation of 1,3-propanediol is preferred over the use of
oxetane since it is a less hazardous, very stable, low cost,
commercially available material and can be prepared by use of petro
chemical feed-stocks or renewable resources.
[0046] Preferably, a bio-route via fermentation of a renewable
resource is used to obtain the 1,3-propanediol. One particularly
preferred renewable resource is corn since it is readily available
and has a high rate of conversion to 1,3-propanediol and can be
genetically modified to improve yields to diol. Typical
bio-conversion processes are shown in U.S. Pat. No. 5,686,276, U.S.
Pat. No. 5,633,362 and U.S. Pat. No. 5,821,092. U.S. Pat. No. '276
teaches a bio-conversion process of a fermentable carbon source to
1,3-propanediol by a single microorganism. U.S. Pat. No. '362 and
U.S. Pat. No. '092 show the bio-conversion of glycerol to
1,3-propanediol by recombinant bacteria harboring a foreign gene
encoding a diol dehydratase. The aforementioned patents are
incorporated herein by reference Copolymers of polytrimethylene
ether diol also can be used. For example, such copolymers are
prepared by copolymerizing 1,3-propanediol with another diol, such
as, ethane diol, hexane diol, 2-methyl 1,3-propanediol,
2,2-dimethyl-1,3-propanediol. At least 50% of the copolymer must be
from 1,3-propanediol.
[0047] A blend of a high and low molecular weight polytrimethylene
ether diol can be used wherein the high molecular weight diol has
an Mn of 1,000 to 4,000 and the low molecular weight diol has an Mn
of 150 to 500. The average Mn of the diol should be in the range of
1,000 to 4,000. Also, the diol can contain polytrimethylene ether
triols and other higher functionality polytrimethylene ether
polyols in an amount of 1 to 20% based on the weight of the
polytrimethylene ether diol.
[0048] Blends of the polytrimethylene ether diol and other
cycloaliphatic hydroxyl containing either branched or linear
oligomers can be used. Such oligomers are disclosed in Barsotti, et
al. U.S. Pat. No. 6,221,494, which is hereby incorporated by
reference. Up to 30% by weight, based on the weight of the diol, of
such oligomers can be used.
[0049] Coatings formed from compositions of this invention
containing polytrimethylene ether diols in particular have better
chip resistance properties in comparison to coating prepared from
conventional diols, for example, polytetramethylene ether diols and
polyoxypropylene diols.
[0050] A variety of crosslinking agents can be used in the novel
composition of this invention, such as, organic polyisocyanates,
melamine formaldehydes, alkylated melamine formaldehydes,
benzoquanamine formaldehyde, urea formaldehyde, polyepoxides,
silane resins and any mixtures thereof.
[0051] Typically useful organic polyisocyanates crosslinking agents
that can be used include aliphatic polyisocyanates, cycloaliphatic
polyisocyanates, aromatic polyisocyanates and isocyanate
adducts.
[0052] Examples of suitable aliphatic, cycloaliphatic and aromatic
polyisocyanates that can be used include the following: 2,4-toluene
diisocyanate, 2,6-toluene diisocyanate ("TDI"), 4,4-diphenylmethane
diisocyanate ("MDI"), 4,4'-dicyclohexyl methane diisocyanate,
("H.sub.12MDI"), 3,3'-dimethyl-4,4'-biphenyl diisocyanate ("TODI"),
1,4-benzene diisocyanate, trans-cyclohexane-1,4-diisocyanate,
1,5-naphthalene diisocyanate ("NDI"), 1,6-hexamethylene
diisocyanate ("HDI"), 4,6-xylene diisocyanate, isophorone
diisocyanate, ("IPDI"), other aliphatic or cycloaliphatic di-, tri-
or tetra-isocyanates, such as, 1,2-propylene diisocyanate,
tetramethylene diisocyanate, 2,3-butylene diisocyanate,
octamethylene diisocyanate, 2,2,4-trimethyl hexamethylene
diisocyanate, dodecamethylene diisocyanate, omega-dipropyl ether
diisocyanate, 1,3-cyclopentane diisocyanate, 1,2-cyclohexane
diisocyanate, 1,4-cyclohexane diisocyanate,
4-methyl-1,3-diisocyanatocyclohexane,
dicyclohexylmethane-4,4'-diisocyanate,
3,3'-dimethyl-dicyclohexylmethane 4,4'-diisocyanate,
polyisocyanates having isocyanurate structural units, such as, the
isocyanurate of hexamethylene diisocyanate and the isocyanurate of
isophorone diisocyanate, the adduct of 2 molecules of a
diisocyanate, such as, hexamethylene diisocyanate, uretidiones of
hexamethylene diisocyanate, uretidiones of isophorone diisocyanate
and a diol, such as, ethylene glycol, the adduct of 3 molecules of
hexamethylene dilsocyanate and 1 molecule of water, allophanates,
trimers and biurets, for example, of hexamethylene diisocyanate,
allophanates, trimers and biurets, for example, of isophorone
diisocyanate and the isocyanurate of hexane diisocyanate. MDI, HDI,
TDI and isophorone diisocyanate are preferred because of their
commercial availability.
[0053] Tri-functional isocyanates also can be used, such as,
triphenyl methane triisocyanate, 1,3,5-benzene triisocyanate,
2,4,6-toluene triisocyanate. Trimers of diisocyanates, such as, the
trimer of hexamethylene diisocyanate sold as Tolonate.RTM. HDT from
Rhodia Corporation and the trimer of isophorone diisocyanate are
also suitable.
[0054] An isocyanate functional adduct can be used, such as, an
adduct of an aliphatic polyisocyanate and a polyol or an adduct of
an aliphatic polyisocyanate and an amine. Also, any of the
aforementioned polyisocyanates can be used with a polyol to form an
adduct. Polyols, such as, trimethylol alkanes, particularly,
trimethylol propane or ethane can be used to form an adduct.
[0055] A particularly useful coating composition useful for the
interior of automobiles and truck that forms a finish with a soft
leather like touch or feel comprises the polytrimethylene ether
diol and an organic polyisocyanate crosslinking agent. Typically,
such compositions comprise a binder of about 40 to 90% by weight of
the polytrimethylene ether diol and 10 to 60% by weight of an
organic polyisocyanate crosslinking agent. O'Neil U.S. Pat. No.
6,207,224 and O'Neil U.S. Pat. No. 6,436,478 disclose such
compositions and are hereby incorporated by reference. The
polytrimethylene ether glycol can be the polyol component of the
coating compositions disclosed in these patents. Such compositions
have excellent appearance, good adhesion to thermoplastic
substrates, have a soft feel but still have sufficient hardness to
avoid scratching and marring and are comparable to commercially
available compositions of this type.
[0056] Typical alkylated melamines that can be used as the cross
linking component are monomeric or polymeric and have a relatively
low molecular weight. Alkoxy monomeric melamines that can be used
are low molecular weight melamines that contain on an average three
or more methylol groups reacted with a monohydric alcohol having 1
to 5 carbon atoms, such as, methanol, propanol, n-butanol and
isobutanol and have an average degree of polymerization of less
than 2 and preferably, in the range of about 1.1 to 1.8.
[0057] Suitable monomeric melamines include highly alkylated
melamines, such as, methylated melamines, methylated and butylated
melamines, butylated melamines, isobutylated melamines and mixtures
thereof. More particularly, hexamethoxymethylol melamine, butylated
melamines and mixed methylated and butylated melamines are
preferred. Particularly preferred alkylated melamines include
hexamethoxymethylol melamines, such as, Cymel.RTM. 301 and 303 and
Resimene.RTM. 747, Cymel.RTM. 1156 which is reported to be a 100%
butylated melamine having a degree of polymerization of 2.9. A
particularly preferred mixture of melamines is Cymel.RTM. 1156 and
Resimene.RTM. CE-4514 which is reported to be a 50/50
methylated/butylated melamine.
[0058] A typically useful polymeric melamine is Cymel.RTM. 327
which is a highly methylated melamine having a degree of
polymerization of 1.8. Other polymeric melamines, such as,
Cymel.RTM. 328 can also be used.
[0059] These melamines are supplied commercially; for example, by
Cytec Industries Inc., Stamford, Conn., and by Solutia Inc.,
Springfield, Mass.
[0060] Polyepoxide resins also can be used as the crosslinking
component. Any of the aforementioned polyepoxide resins can be used
as the crosslinking agent. Generally, if a polyepoxide is used as
the crosslinking agent, it is not used as component a. of the novel
composition.
[0061] Other useful crosslinking components are melamine
formaldehyde, benzoguanamine formaldehyde, and urea
formaldehyde.
[0062] A silane crosslinking component also can be used. One useful
silane crosslinking component is an aminofunctional silane
crosslinking agent usually in an amount of 0.1 to 50% by weight,
based on the weight of the binder; preferably, 0.5 to 10.0% by
weight of silane is used. Typically useful aminofunctional silanes
have the formula
(X.sub.nR).sub.aSi--(--OSi).sub.y--(OR.sup.3).sub.b wherein X is
selected from the group of --NH.sub.2, --NHR.sup.4, and SH, n is an
integer from 1-5, R is a hydrocarbon group contain 1 to 22 carbon
atoms, R.sup.3 is an alkyl group containing 1 to 8 carbon atoms, a
is at least 1, y is from 0 to 20, b is at least 2 and R.sup.4 is an
alkyl group having 1 to 4 carbon atoms.
[0063] Typically useful aminofunctional silanes are
aminomethyltriethoxysilane, gamma-aminopropyltrimethoxysilane,
gamma-aminopropyltriethoxysilane,
gamma-aminopropylmethyidiethoxysilane,
gamma-aminopropylethyldiethoxysilane,
gamma-aminopropylphenyldiethoxyysilane,
N-beta(aminoethyl)gamma-aminopropyltrimethoxysilane,
delta-aminobutyltriethoxysilane,
delta-aminobutylethyldiethoxysilane and diethylene triamino
propylaminotrimethoxysilane. Preferred are
N-beta(aminoethyl)gamma-aminopropyltrimethoxysilane commercially
sold as Silquest.RTM. A 1120 and diethylene triamino
propylaminotrimethoxysilane that is commercially sold as
Silquest.RTM. A 1130. Both of theses silanes are sold by OSi
Specialties, Inc. Danbury, Conn.
[0064] When an amino silane crosslinking agent is used, additional
amino functional curing agents, such as, primary, secondary and
tertiary amines, that are well known in the art are usually added.
Typically, aliphatic amines containing a primary amine group, such
as, diethylene triamine, and triethylene tetramine can be added.
Tertiary amines, such as, tris-(dimethyl aminomethyl)-phenol can
also be used.
[0065] The novel composition can contain 1 to 50% by weight,
preferably, 20 to 40% by weight, based on the weight of the binder
of acrylic NAD (non-aqueous dispersed) resins. These NAD resins
typically are high molecular weight resins having a crosslinked
acrylic core with a Tg between 20 to 100.degree. C. and attached to
the core are low Tg stabilizer segments. A description of such NAD
resins is in Antonelli et al. U.S. Pat. No. 4,591,533, Antonelli et
al. U.S. Pat. No. 5,010,140 and in Barsofti et al. U.S. Pat. No.
5,763,528. These patents are hereby incorporated by reference.
[0066] Typically, a catalyst is used in the novel composition to
reduce curing time and temperature and allow curing of the coating
at ambient temperatures. Typical catalysts include dibutyl tin
dilaurate, dibutyl tin diacetate, dibutyl tin dichloride, dibutyl
tin dibromide, triphenyl boron, tetraisopropyl titanate,
triethanolamine titanate chelate, dibutyl tin dioxide, dibutyl tin
dioctoate, tin octoate, aluminum titanate, aluminum chelates,
zirconium chelate, hydrocarbon phosphonium halides, such as, ethyl
triphenyl phosphonium iodide and other such phosphonium salts, and
other catalysts or mixtures thereof known to those skilled in the
art.
[0067] The novel composition typically is solvent based and has a
solids content of 30 to 90% by weight, preferably, 50 to 80% by
weight and more preferably, 60 to 80% by weight, of binder of a
ready to spray composition. The novel composition may be formulated
at 100% solids by using reactive diluents of low molecular weight
resin(s), such as, an acrylic resin.
[0068] Any of the known organic solvents may be used to form the
coating composition. Typical solvents include aromatic
hydrocarbons, such as, toluene, xylene; ketones, such as, acetone,
methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and
diisobutyl ketone; esters, such as, ethyl acetate, n-butyl acetate
and isobutyl acetate. Typical alcohols that can be used are
ethanol, propanol, isopropanol, butanol, isobutanol, tertiary
butanol, and diacetone alcohol and mixtures of any of the above.
Alcohols are not used in the presence of isocyanate crosslinking
agents.
[0069] An advantage of the novel coating composition of this
invention is that it has a low VOC (volatile organic content) and
can readily be formulated to have a VOC of less than 334 g/l (2.8
pounds per gallon) and in particular can be formulated to a VOC
less than 240 g/l (2 pound per gallon) that meets current
governmental air pollution regulations.
[0070] The composition can contain pigments in a pigment to binder
weight ratio of 1/100 to 350/100. When the composition is used as a
primer, conventional primer pigments are used in a pigment to
binder weight ratio of 50/100 to 350/100. Typical of such pigments
that are useful in primers are titanium dioxide, zinc phosphate,
iron oxide, carbon black, amorphous silica, high surface area
silica, barium sulfate, talc, chromate pigments for corrosion
resistance, such as, calcium chromate, strontium chromate, zinc
chromate, magnesium chromate, barium chromate and hollow glass
spheres. If the coating composition is used as a base coat or
topcoat coating composition, metallic flakes and powders, such as,
aluminum flake and aluminum powders; special effects pigments, such
as, coated mica flakes, coated aluminum flake, colored pigments and
inorganic or organic colored pigments may be used usually in
combination with one of the aforementioned pigments.
[0071] Suitable pigments and extenders that can be used are, for
example, inorganic or organic coloring pigments like titanium
dioxide, micronised titanium dioxide, iron oxide pigments, carbon
black, azo pigments, phthalocyanine pigments, quinacridone or
pyrrolopyrrole pigments. Examples of special effect pigments are
metal pigments, for example made from aluminium or copper,
interference pigments, such as, titanium dioxide coated aluminium,
coated mica; graphite special effect pigments and iron oxide in
flake form. Examples of extenders are silicon dioxide, barium
sulfate, talcum, aluminium silicate and magnesium silicate.
[0072] If the novel coating composition is to be used as an
exterior coating or as a coating that is subject to weathering
and/or exposure to UV light, weatherability and UV durability of
the coating can be improved by the addition of an ultraviolet light
stabilizer or a combination of ultraviolet light stabilizers in the
amount of 0.1% to 10% by weight, based on the weight of the binder.
Such stabilizers include ultraviolet,light absorbers, screeners,
quenchers, and specified hindered amine light stabilizers. An
antioxidant also can be added, in the amount of 0.1% to 5% by
weight, based on the weight of the binder.
[0073] Typical ultraviolet light stabilizers that are useful
include benzophenones, triazoles, triazines, benzoates, hindered
amines and mixtures thereof. Specific examples of ultraviolet
stabilizers are disclosed in Antonelli et al. U.S. Pat. No.
4,591,533, the entire disclosure of which is incorporated herein by
reference. For good durability, a blend of Tinuvin.RTM. 928 and
Tinuvin.RTM. 123 (hindered amine light stabilizers), all
commercially available from Ciba Specialty Chemicals, Tarrytown,
N.Y. is preferred.
[0074] The coating compositions may contain conventional coating
additives. The additives comprise the conventional additives usable
in the coatings. Examples of such additives are leveling agents
based on (meth)acrylic homopolymers, Theological agents, such as
highly disperse silica or polymeric urea compounds, thickeners,
such as partially cross-linked polycarboxylic acid or
polyurethanes, antifoaming agents, wetting agents, catalysts for
the cross-linking reaction of the OH-functional binders, for
example organic metal salts, such as, dibutyltin dilaurate, zinc
naphthenate and compounds containing tertiary amino groups, such
as, triethylamine, for the cross-linking reaction with
polyisocyanates. The additives are used in conventional amounts
familiar to the person skilled in the art.
[0075] The novel coating composition may also contain other
conventional formulation additives, such as, wetting agents,
leveling and flow control agents, for example, Resiflow.RTM.S
(polybutylacrylate), BYK.RTM. 320 and 325 (high molecular weight
polyacrylates), BYK.RTM. 347 (polyether-modified siloxane) and
rheology control agents, such as, fumed silica.
[0076] In addition to component a., the coating compositions
according to the invention may contain further reactive low
molecular weight compounds as reactive diluents that are capable of
reacting with the cross-linking component c. For example, low
molecular weight polyhydroxyl compounds, such as, ethylene glycol,
propylene glycol, trimethylolpropane and 1,6-dihydroxyhexane may be
used.
[0077] The coating compositions according to the invention may be
transparent or pigmented coating compositions. Pigmented coating
compositions are produced by mixing the individual constituents
with one another and homogenizing or grinding them in conventional
manner. It is, for example, possible to proceed by initially mixing
a proportion of component a. and/or component b. with the pigments
and/or extenders and the additives and solvents conventional in
coatings and grinding the mixture in grinding units.
[0078] Depending upon the type of cross-linking agent (component
c.), the novel composition may be formulated as a single-component
or two-component coating compositions. If polyisocyanates with free
isocyanate groups are used as the cross-linking agent, the coating
compositions are two-component systems, i.e. components a. and b.
may be mixed with the polyisocyanate component only shortly before
application. If blocked polyisocyanates and/or amino resins are,
for example, used as the cross-linking agent, the coating
compositions may be formulated as a single component composition.
The coating compositions may, in principle, additionally be
adjusted to spraying viscosity with organic solvents before being
applied.
[0079] In a typical two component composition, the two components
are mixed together shortly before application. The first component
contains the polymer having pendant reactive groups, such as, an
acrylic polymer having reactive hydroxyl groups, and the
polytrimethylene ether diol and pigments. The pigments can be
dispersed in the first component using conventional dispersing
techniques, such as, ball milling, sand milling attritor grinding,
and the like. The second component contains the crosslinking agent,
such as, a polyisocyanate crosslinking agent, and an optional amino
functional silane crosslinking agent and an optional additional
amine curing agents and solvents.
[0080] The coating compositions according to the invention are
suitable for vehicle and industrial coating and may be applied by
using known processes, in particular spray application. In the
context of vehicle coating, the coating compositions may be used
both for vehicle original coating and for repair or refinish
coating of vehicles and vehicle parts. Curing temperatures depend
on the crosslinking agent used. For example, if the crosslinking
agent is a polyisocyanate, cure can be accomplished at ambient
temperatures but the composition also can be force dried at
elevated temperature of 50 to 150.degree. C. Typical baking
temperatures used for heat crosslinkable agents, such as, alkylated
melamines, are 60 to 160.degree. C., preferably of 100 to
140.degree. C. and are generally used for original vehicle
coatings. Curing temperatures of 20.degree. C. to 80.degree. C., in
particular of 20 to 60.degree. C., are used for vehicle repair or
refinish coating in which the crosslinking agent typically is a
polyisocyanate.
[0081] The coating compositions according to the invention may be
formulated as pigmented or transparent coatings. They may be used
for the production of the outer pigmented top coat layer of a
multi-layer coating and for the production of the filler and/or
primer coat of a multi-layer coating. The present invention also
relates to the use of the coating compositions according to the
invention as top coat coating compositions and as filler and primer
coating compositions and to a process for the production of
multi-layer coatings, wherein, in particular, the pigmented top
coat and the filler and primer coats of multi-layer coatings are
produced by the coating compositions according to the
invention.
[0082] Heat activated crosslinking agents, such as, alkylated
melamine formaldehydes, can be added directly to the coating
composition containing the polymer having pendant reactive groups
and the polytrimethylene ether diol at any time prior to
application since there is no reaction between the crosslinking
agent and the other components until after the coating is applied
and baked at an elevated temperature.
[0083] The coating composition can be applied by conventional
techniques, such as, spraying, electrostatic spraying, dipping,
brushing, and flow coating. Typically, the coating is applied to a
dry film thickness of 50 to 300 microns and preferably, 75 to 200
microns.
[0084] Cured clear films (non-pigment containing films) of the
novel coating composition formulated with a polymer, for example,
an acrylic polymer, have excellent elastic and hardness properties
and the Tg of the cured film is greater than 50.degree. C. which is
surprising since the diol used in the composition has a Tg of
-75.degree. C. While not wishing to be bound by a theory, it is
believed the polymer provides the hardness to the coating while the
polytrimethylene ether diol segment provides improved flexibility
and thus provides a coating with improved chip resistance and
desired hardness.
[0085] When pigmented and formulated into a primer and cured, the
composition of this invention forms finishes having a high
excellent flexibility, good adhesion to metal substrates, provides
good filling of surface imperfections, can easily be sanded in a
short time after application and curing and provides excellent
stone chip resistance. In particular, the coating composition has a
good cure response at ambient temperatures and excellent cure
response at elevated temperature curing conditions.
Testing Procedures Used in the Examples
[0086] Dry Film Thickness--test method ASTM D4138
[0087] Gravelometer--similar to test method ASTM D3170. A 90 degree
panel angle is used, with panels and stones conditioned in a
freezer held at -26.degree. C. to -36.degree. C. for a minimum of 2
hours prior to testing. One pint of such frozen stones is used in
the test. Additionally, 3 pints of room-temperature stones are used
on panels stored at room temperature to provide additional
information. Panels are rated from 1 to 9 with 1 being the worst
(very severe chipping) and 9 being the best (almost no chipping).
Optionally, the area (in square millimeters) of the largest chip is
also considered in assessing the performance of the coating.
[0088] Persoz Hardness Test--the change in film hardness of the
coating was measured with respect to time after application by
using a Persoz Hardness Tester Model No. 5854 [ASTM D4366] supplied
by Byk-Mallinckrodt, Wallingford, Conn. The number of Oscillations
[referred as Persoz No.] are recorded.
[0089] Hardness--was measured using a Fischerscope.RTM. Hardness
Tester. [The measurement is in Newtons per square millimeter.]
[0090] Tg (glass transition temperature) of a polymer is determined
according to ASTM D-3418 (1988).
[0091] Molecular weight and hydroxyl number of the polytrimethylene
ether diol are determined according to ASTM E222.
[0092] Molecular weights Mw and Mn and the polydispersity (Mw/Mn)
of the acrylic polymer and other polymers are determined by GPC
(Gel Permeation Chromatography) using polystyrene standards and
tetrahydrofuran as the solvent.
[0093] Percent strain to break and energy to break were obtained on
a Model 1122 Instron electromechanical test machine modified for
computer control and data reduction and maintained according the
standards of ISO 9001. Test sample width was 12.7 mm and thickness
was approximately 0.1 mm; the exact thickness was determined with a
calibrated micrometer. The gage length was 12.7 mm and test speed
was 5.0 mm/min. All results were obtained under ambient laboratory
conditions.
[0094] The following examples illustrate the invention. All parts
and percentages are on a weight basis unless otherwise indicated.
Abbreviation "PBW" means parts by weight.
EXAMPLES
Example 1
Preparation of (polytrimethylene ether diols A and B)
[0095] 1,3-Propanediol (3.4 kg) and concentrated sulfuric acid
(30.4 g) were placed in a 5 L three neck round bottom flask fitted
with a nitrogen inlet, mechanical stirrer and a distillation head.
Nitrogen gas was bubbled through the reaction mixture for 15
minutes. The polymerization was carried out at 160.degree. C. with
stirring under a nitrogen atmosphere. After collecting 525 g of
water distillate in a receiving flask, the flask was connected to a
vacuum pump and the pressure was slowly reduced to 1-5 mm Hg. The
molecular weight of the resulting reaction product was monitored by
analyzing the samples at different time intervals using an NMR end
group analysis method. The polymerization was stopped after
obtaining the desired molecular weight (approximately 2,000) and
the polymer was purified as described below.
[0096] An equal volume of water was added to the crude polymer and
the reaction mixture was refluxed at 100.degree. C. for about 6
hours and a stirring speed of 180 rpm was used under a nitrogen
atmosphere. After approximately 6 hours, the heater and the stirrer
were turned off and the mixture was allowed to separate into two
phases. The top aqueous phase was decanted and the polytrimethylene
ether diol phase was washed further with distilled water three more
times to extract out most of the acid and the oligomers that were
formed. The residual acid left in the polytrimethylene ether diol
was neutralized with excess lime. The polytrimethylene ether diol
was dried at about 100.degree. C. under reduced pressure for 2-3
hours and then the dried diol was filtered while hot through a
Whatman filter paper pre-coated with a Celite.RTM. filter aid. The
polytrimethylene ether diol was analyzed and the properties are
listed in Table 1 below. A second polytrimethylene ether diol B was
prepared as above and the properties are shown in Table 1.
TABLE-US-00001 TABLE 1 Properties of polytrimethylene ether diols A
and B Polytrimethylene ether diol A B Number Average Molecular
Weight (Mn) 1850 2738 Hydroxyl Number 60.6 41.0
Preparation of Primer Millbase Compositions A-C
[0097] Primer millbase compositions A, B, and C were prepared by
charging the following ingredients into a mixing vessel:
TABLE-US-00002 Primer Millbase Compositions A B C Description of
Material PBW PBW PBW Portion 1 Butyl acetate 130.90 84.38 52.17
Xylene 21.30 21.81 22.21 Methyl amyl ketone 23.20 23.81 24.25
Methyl isobutyl ketone 75.30 77.09 78.50 Polytrimethylene ether
diol B Mn 2738 75.70 38.75 -- (prepared above) Ethylene oxide
oligomer.sup.(1) 0.0 48.44 98.64 Hydroxy acrylic polymer.sup.(2)
295.20 305.97 -- Hydroxy acrylic polymer.sup.(3) -- -- 307.9
BYK-320 dispersion (Polysiloxane resin 3.80 3.88 3.95 available
from Byk Chemie) Anti-Terra U (salt of a long chain 2.80 2.82 2.87
polyamine-amide and high molecular weight ester) Dibutyl tin
diacetate (10% solution in 1.70 1.89 2.07 xylene) Bentone .RTM.-34
(dispersion of Bentone .RTM. 76.60 78.44 79.87 34 from Elementis
Specialties) Portion 2 Talc N 503 (talc pigment) 91.60 93.79 95.50
Talc D30E (talc pigment) 134.90 138.21 140.73 ZEEOS G 200 (hollow
glass beads 337.40 345.57 351.88 from Eastech Chemical) Portion 3
Blanc Fixe (barium sulfate pigment) 119.90 122.75 124.99 Titanium
dioxide pigment 106.10 108.70 110.69 Carbon black pigment 2.30 2.34
2.38 Portion 4 Acetic acid 1.30 1.38 1.40 Total 1500.00 1500.00
1500.00 Ethylene oxide oligomer.sup.(1) - reaction product of 1
mole of pentaerythritol, 4 moles of methyl hexahydrophthalic
anhydride and 4 moles of ethylene oxide. Hydroxy acrylic
polymer.sup.(2) - acrylic polymer of 37 parts styrene, 17.5 parts
isobornyl methacrylate, 25.5 parts hydroxyethyl methacrylate, 20
parts 2-ethylhexyl methacrylate having a Mw of 15,000 and a Tg of
68.degree. C. Hydroxy acrylic polymer.sup.(3) - acrylic polymer of
37 parts styrene, 23 parts hydroxyethyl acrylate, 40 parts
2-ethylhexyl methacrylate having a Mw of 15,000 and a Tg of
20.degree. C.
[0098] In the preparation of each of the Primer Millbase
Compositions A, B and C, Portion 1 was charged into the mixing
vessel and stirred for 15 minutes. Portion 2 was premixed and
slowly added to the mixing vessel with stirring and stirred for 30
minutes. Portion 3 was premixed and slowly added to the mixing
vessel with stirring and stirred for 60 minutes. Portion 4 was
added and stirred for 15 minutes and the resulting mixture was
ground 3 passes in a top feed sand mill using glass media for 3
passes. Since Primer Millbase Composition C does not contain
polytrimethylene ether diol, it is considered to be a comparative
composition.
[0099] The resulting Primer Millbases A to C have the following
properties: TABLE-US-00003 Primer Millbase A B C Weight % solids
70.2 72.0 73.4 Volume % solids 49.8 51.6 53.3 Pigment/Binder ratio
312.85/100 309.71/100 309.7/100 Pigment Vol. Concentration (%) 53.7
54.2 54.0 Gallon Weight (#/gal) 12.09 12.36 12.49
[0100] Activated Primer Compositions A to C were prepared by
blending the following ingredients together shortly before spray
application: TABLE-US-00004 Activated Primer Comp. A B C Primer
Mill Base 166.40 161.95 157.69 Reducer.sup.(3) 18.80 18.32 17.84
Activator.sup.(4) 14.80 19.73 24.46 Total 200.00 200.00 200.00
Reducer.sup.(3) - 12375S - blend of hydrocarbon solvents
commercially available from E.I. DuPont de Nemours and Company,
Wilmington, Delaware. Activator.sup.(4) - 12305S - Tolonate .RTM.
HDT trimer of hexamethylene diisocyanate (Rhodia Inc.) activator is
commercially available from E.I. DuPont de Nemours and Company,
Wilmington, Delaware.
[0101] The resulting Activated Primer Compositions A to C have the
following properties: TABLE-US-00005 Activated Primer Comp. A B C
NCO:OH ratio 1.1:1.0 1.1:1.0 1.1:1.0 Weight % solids 62.92 64.46
65.50 Volume % solids 43.21 44.95 46.46 Gallon Weight (#/gal) 11.02
11.11 11.10 VOC* (calculated #/gal) 4.09 3.94 3.82 VOC volatile
organic content.
[0102] The above prepared Activated Primer Compositions A to C were
each applied by spraying onto separate cold rolled steel panels
coated with about 0.3 to 0.6 mils (7.5 to 15 microns) of a
commercial refinish wash primer (described below) and the Activated
Primer Composition was cured at ambient temperature. After curing,
the resulting dry film thickness of the primer composition was in
the range of 4 to 7 mils (100 to 178 microns). The Persoz Hardness
and the Fischer Hardness were measured for each of the panels and
shown in Tables 2 and 3 below. Primer C panels were retested
(Primer C did not contain the polytrimethylene ether diol).
TABLE-US-00006 TABLE 2 Persoz Hardness of Activated Primer
Compositions A to C Primer 3 Hours 1 Day A 30 66 B 30 51 C 34 36 C
(retest) 34 36
[0103] TABLE-US-00007 TABLE 3 Fischer Hardness of Activated Primer
Compositions A to C Primer 1 day 7 days 18 days 21 days A 48 84 110
133 B 27 84 110 133 C 21 51 59 60 C (retest) 23 46 64 64
[0104] The above data in Tables 2 and 3 shows that Primer
Compositions A and B that contained the polytrimethylene ether diol
increased in hardness on curing whereas Primer Composition C, which
did not contain the polytrimethylene ether diol, did not increase
significantly in hardness on curing. Table 2 containing the Persoz
Hardness data, shows that the Persoz Hardness approximately doubled
from 3 hours to 24 hours after application for Primer Compositions
A and B whereas the Persoz Hardness for Primer C only increased
slightly. Table 3 containing Fischer Hardness data, shows that the
hardness of Primer Compositions A and B is approximately double
that of Primer Composition C after 18 and 21 days. Due to the
similar hardness values at short times, sandability is expected to
be similar for Primer Compositions A to C.
[0105] The commercial refinish wash primer utilized to prime the
above steel panels is formulated by mixing Variprime.RTM. 615S
(pigmented component) and Variprime.RTM. 616S (reducer component)
in a 1/1 volume ratio (weight ratio of 120 g of 615S/80 g of 616S)
to form a composition having a total solids content of 28.43%,
binder solids of 8.39%, pigment to binder weight ratio of 239/100,
VOC (#/gal) 5.891 and a gallon weight (#/gal) of 5.42. The binder
of the primer is a combination of phenolic/polyvinyl
butyral/nitrocellulose resin. The pigment portion of 615S contains
zinc chromate pigment in the amount of 5.3% on the total formula
composition by weight. The reducer (616S) contains phosphoric acid
in the amount of 2.2% by weight based the total formula weight.
615S and 616S are commercial products available from E.I. DuPont de
Nemours and Company, Wilmington, Del.
[0106] A set of panels primed with Primer Compositions A to C was
prepared as above. The panels were allowed to cure overnight at
about 24.degree. C. and 50% relative humidity, and were then sanded
with 400 grit sandpaper to give a film build of about 4.0 to 4.5
mils (102 to 114 microns). Each of the panels was coated with an
un-activated blue metallic base coat--ChromaBase.RTM. Blue Metallic
basecoat N 8112K (hydroxy functional acrylic polymer dispersion
containing dispersed aluminum flake pigments, phthalocyanine blue
pigment and carbon black pigment) and Chromasystems Basemaker 7175S
(acrylic resin in organic solvents--available from E.I. DuPont de
Nemours and Company, Wilmington, Delaware). One part of N8112K is
mixed with one part 7175S to form an unactivated base coat. Each
panel was top coated with a clear top coat (DuPont ChromaClear.RTM.
V-7500S two component urethane clear coat commercially available
from E.I. DuPont de Nemours and Company, Wilmington, Del.).
[0107] Another panel was prepared as above with Primer Composition
C and the blue metallic base coat was activated with
ChromaPremier.RTM. 12305S isocyanate activator.
[0108] A second set of panels coated with Primer Composition A to C
and prepared as described above was coated with an unactivated red
base coat--ChromaBase.RTM. Red Basecoat B8713K (hydroxyfunctional
acrylic polymer dispersion containing Monastral.RTM. Magenta
pigment dispersion and Perrindo.RTM. red dispersion) and
Chromasystems Basemaker 7175S (acrylic resin in organic solvents).
One part of B8731K was mixed with one part of 7175S. Each of the
panel was coated with a clear top-coat (described above).
[0109] Another panel was prepared as above with Primer Composition
C except the base coat was activated with the ChromaPremier.RTM.
12305S isocyanate activator.
[0110] Each of the above prepared sets of panels was tested for
chip resistance using the Gravelometer test as described above. The
results are shown in Table 4 below. TABLE-US-00008 TABLE 4
Gravelometer Test Results 3 Pints Stones Room Gravelometer Test
Temp. 1 Pint Stones Frozen Blue Metallic Base Coat Primer A 5 7
Primer B 3 5 Primer C 3 4 Primer C with Activated 5 7 Base Coat Red
Base Coat Primer A 5 6 Primer B 3 4 Primer C 1 2 Primer C with
Activated 6 6 Base Coat
[0111] The above data shows that for both the panels of the Blue
Metallic Base Coat and the Red Base Coat, Primers A and B that
contained polytrimethylene ether diol have a higher Gravelometer
chip rating at room temperature and at a low temperature in
comparison to Primer C that did not contain polytrimethylene ether
diol. In both cases, the blue metallic and the red activated base
coats in combination with Primer C did not significantly increase
the chip resistance in comparison to Primer A that contained the
polytrimethylene ether diol. Normally, an activated base coat
increases chip resistance. Primer B shows some improvement as
compared to Primer C used with an un-activated basecoat. This shows
that the addition of polytrimethylene ether diol in combination
with an ethylene oxide oligomer improves chip performance in
comparison to the use of only ethylene oxide oligomer in Primer
C.
Example 2
[0112] The following clear coating compositions D, E, and F were
prepared by charging the following ingredients into a mixing vessel
and thoroughly mixing the ingredients: TABLE-US-00009 Clear Coating
Compositions D E F Description of Material PBW PBW PBW Hydroxy
acrylic polymer.sup.(3) -- -- 90.0 Hydroxy acrylic polymer.sup.(2)
90 90 -- Polytrimethylene ether diol Mn 1810 23 -- -- Ethylene
oxide oligomer.sup.(1) -- 28.8 29.2 Dibutyl tin dilaurate (10%
solution in 0.21 0.24 0.24 xylene) Butyl acetate 30.5 34.8 35.7
Xylene 23.5 24.0 24.7 Methyl amyl ketone 30.5 34.8 35.7 Byk-333
from Byk-Chemie 0.06 0.07 0.07 Activator.sup.(4) 34.9 53.9 54.9
Total 232.67 266.61 270.5 Hydroxy acrylic polymer.sup.(2) -
described in Example 1. Hydroxy acrylic polymer.sup.(3) - described
in Example 1. Ethylene oxide oligomer.sup.(1) - described in
Example 1. Activator.sup.(4) - described in Example 1.
[0113] The above prepared Clear Coating Compositions D to F were
each applied with a draw-down bar over electrocoated steel panels
to give a dry film thickness of 2 mils (51 microns) and the
resulting clear coating compositions were cured at an ambient
temperature of about 24.degree. C. The Persoz Hardness and the
Fischer Hardness were measured for each of the panels at different
times and the data is shown in Tables 5 and 6 below. The Tg, %
Strain to Break, and Energy to Break were measured for each of the
clear coating compositions after curing for 30 days at about
24.degree. C. and 50% relative humidity and the results are shown
in Table 7 below. TABLE-US-00010 TABLE 5 Persoz Hardness of Clear
Coating Compositions D to F Clear Coating 3 Hours 1 Day D 10 78 E
17 175 F 4 60
[0114] TABLE-US-00011 TABLE 6 Fischer Hardness Clear Coating
Compositions D to F Clear Coating 1 day 7 days 14 days 21 days D
24.5 102 104 109 E 55 145 151 156 F 8.6 124 135 136
[0115] TABLE-US-00012 TABLE 7 Tg, % Strain at Break and Energy to
Break Clear Coatings D to F Clear % Strain to Energy to Break
Coating Tg Break (mi/sq.mm) D 60.3 52.6 112.4 E 63.7 7.0 32.8 F
58.0 6.6 31.2
[0116] Clear Coating Composition F is a comparative composition
that was formulated with a low Tg acrylic polymer (Tg 20.degree.
C.). Clear Coating Composition E is a comparative composition that
was formulated with a high Tg acrylic polymer (Tg 68.degree. C.).
Clear Coating Composition D is a preferred composition of the
invention and was also formulated with the same high Tg acrylic
polymer. Clear Coating Composition D has acceptable hardness values
(Persoz and Fischer) but significantly higher % Strain to Break and
Energy to Break which typically translates into a more durable
clear coating composition that is useful on automobiles and truck
in comparison to Clear Coating Compositions E and F. Clear Coating
Composition E that used the same high Tg acrylic polymer as Clear
Coating Composition D but did not use the polytrimethylene ether
diol but rather a ethylene oxide oligomer had high hardness but
significantly lower % Strain to Break and Energy to Break in
comparison to Clear Coating Composition D which represents the
invention. Similarly, Clear Coating Composition F that used the low
Tg acrylic polymer and the ethylene oxide oligomer had
significantly lower % Strain to Break and Energy to Break in
comparison to Clear Coating Composition D which represents the
invention.
Example 3
[0117] The following clear coating compositions G through K were
prepared by charging the following ingredients into a mixing vessel
and thoroughly mixing the ingredients: TABLE-US-00013 Clear Coating
Compositions G H I J K Description of Material PBW PBW PBW PBW PBW
Hydroxy acrylic polymer.sup.(2) 58.7 58.6 58.0 50.5 68.7
Polytrimethylene ether diol 15.1 -- -- -- -- Mn 2753 PPG
2000.sup.(5) -- 15.0 -- Terathane .RTM. 2000.sup.(6) -- -- 14.9 S
Diol.sup.(7) -- -- -- 12.9 2.2 Dibutyl tin diacetate (10% 0.3 0.3
0.3 .03 .03 solution in xylene) Activator.sup.(4) 25.9 26.1 26.9
36.3 28.8 Total 100.0 100.0 100.0 100.0 100.0 Hydroxy acrylic
polymer.sup.(2) - described in Example 1. PPG 2000.sup.(5) -
Polypropylene glycol having a molecular weight of 2000 from Aldrich
Chemical Company (product no. 81380). Terathane .RTM. 2000.sup.(6)
polyether glycol having a molecular weight of 2023 from E.I. DuPont
de Nemours and Company. S Diol.sup.(7) - hydroxy oligomer (reaction
product of 3 moles of caprolactone and 1 mole of 1,4-cyclohexane
dimethanol). Activator.sup.(4) - described in Example 1.
[0118] The above prepared Clear Coating Compositions G to K were
each applied with a draw-down bar on electrocoated steel panels.
The clear coating compositions were cured at an ambient temperature
of about 24.degree. C. The resulting dry film thickness of each of
the clear coating compositions was in the range of 1.8 to 2.2 mils
(46 to 56 microns).
[0119] The Gel Fraction and Tg of each of the clear films after 30
days curing at about 24.degree. C. and 50% relative humidity were
measured and the results shown in Table 8 following. TABLE-US-00014
TABLE 8 Gel Fraction and Tg (Glass Transition Temperature) Clear
Coating Films G to K Clear Coating Gel Fraction Tg G 97.80% 64.2 H
89.90% 61.4 I 98.10% 58.5 J 93.40% 33.1 K 93.00% 59.8
[0120] The Glass Transition Temperatures (Tg) of the Clear Coating
Films G-I and K were very similar. Clear Coating J had a relatively
low Tg in comparison to the other Clear Coatings. The relatively
large amount of soluble material in Clear Coating Film H indicates
that this film should have poorer long term outdoor durability in
comparison Clear Coatings G and I. Clear Coatings J and K have more
soluble material than Clear Coatings G and I and are also expected
not to have as good long term outdoor durability as Clear Coatings
G and I.
Example 4
Preparation of Primer Millbase Compositions L to P
[0121] Primer millbase compositions L to P were prepared by
charging the following ingredients into a mixing vessel:
TABLE-US-00015 Primer Millbase Compositions L M N O P Description
of Material PBW PBW PBW PBW PBW Portion 1 Butyl acetate 131.0 131.0
131.0 130.9 127.3 Xylene 21.3 21.3 21.3 21.3 20.7 Methyl amyl
ketone 23.3 23.3 23.3 23.2 22.5 Methyl isobutyl ketone 75.3 75.3
75.3 75.2 73.2 Polytrimethylene ether diol Mn 2753 75.7 -- -- -- --
PPG 2000.sup.(5) described in -- 75.7 -- -- -- Example 3 Terathane
.RTM. 2000.sup.(6) -- -- 75.7 -- -- described in Example 3 S
Diol.sup.(7) described in Ex. 3 -- -- -- 75.7 12.3 Hydroxy acrylic
polymer.sup.(2) 295.3 295.3 295.3 295.2 389.6 described in Ex. 1
BYK-320 dispersion (Polysiloxane resin 3.8 3.8 3.8 3.7 3.7
available from Byk Chemie) Anti-Terra U (salt of a long 2.8 2.8 2.8
2.8 2.7 chain polyamine-amide and high molecular weight ester)
Dibutyl tin diacetate (10% 1.7 1.7 1.7 1.9 1.7 solution in xylene)
Bentone .RTM.-34 (dispersion of 76.6 76.6 76.6 76.6 74.5 Bentone
.RTM. 34 from Elementis Specialties) Portion 2 Talc N 503 (talc
pigment) 91.6 91.6 91.6 91.6 89.0 Talc D30E (talc pigment) 134.9
134.9 134.9 134.9 131.3 ZEEOS G 200 (hollow glass 337.4 337.4 337.4
337.4 328.1 beads from Eastech Chemical) Portion 3 Blanc Fixe
(barium sulfate 119.9 119.9 119.9 119.8 116.6 pigment) Titanium
dioxide pigment 106.1 106.1 106.1 106.1 103.2 Carbon black pigment
2.3 2.3 2.3 2.2 2.3 Portion 4 Acetic acid 1.4 1.4 1.4 1.3 1.3 Total
1500 1500 1500 1500 1500
[0122] In the preparation of each of the Primer Millbase
Compositions L to P, Portion 1 was charged into the mixing vessel
and stirred for 15 minutes. Portion 2 was premixed and slowly added
to the mixing vessel with stirring and stirred for 30 minutes.
Portion 3 was premixed and slowly added to the mixing vessel with
stirring and stirred for 60 minutes. Portion 4 was added and
stirred for 15 minutes and the resulting mixture was ground 3
passes in a top feed sand mill using glass media for 3 passes.
Since Primer Millbase Compositions M to P do not contain
polytrimethylene ether diol, they are considered to be comparative
compositions.
[0123] The resulting Primer Millbases L to P have the following
properties: TABLE-US-00016 Primer Millbase L M N O P Weight %
solids 69.9 69.9 69.9 69.9 67.8 Volume % solids 49.1 49.1 52.7 48.9
46.3 Pigment/Binder 318.5/100 318.5/100 318.5/100 318.5/ 321.7/
ratio 100 100 Pigment Vol. 54.61 54.47 47.2 55.01 55.58
Concentration (%) Gallon Weight 12.13 12.13 11.26 12.17 11.98
(#/gal)
[0124] Activated Primer Compositions L to P were prepared by
blending the following ingredients together shortly before spray
application: TABLE-US-00017 Activated Primer Comp. L M N O P Primer
Mill Base 250 249.8 249.1 159.4 163.3 Reducer.sup.(3) 28.3 28.3
28.2 18.0 18.5 Activator.sup.(4) 21.7 21.9 22.7 22.5 17.9 Total
300.0 300.0 300.0 199.9 199.7 Reducer.sup.(3) - described in
Example 1. Activator.sup.(4) - described in Example 1
[0125] The resulting Activated Primer Compositions L to P have the
following properties: TABLE-US-00018 Activated Primer Composition L
M N O P NCO:OH ratio 1.12:1.0 1.12:1.0 1.12:1.0 1.12:1.0 1.12:1.0
Weight % solids 62.6 62.6 62.6 62.7 61.0 Volume % solids 42.6 42.7
41.7 43.3 41.0 Gallon Weight 11.0 11.1 10.4 10.9 10.9 (#/gal) VOC*
(calculated 4.1 4.09 3.9 4.06 4.04 #/gal) VOC volatile organic
content.
[0126] The above prepared Activated Primer Compositions L to P were
each applied by spraying onto separate cold rolled steel panels
coated with about 0.3 to 0.6 mils (7.5 to 15 microns) of a
commercial refinish wash primer (described in Example 1) and the
Activated Primer Composition was cured at ambient temperature. The
resulting dry film thickness of the primer composition was in the
range of 4 to 7 mils (100 to 178 microns). The Persoz Hardness and
the Fischer Hardness were measured for each of the panels and shown
in Tables 9 and 10 below. TABLE-US-00019 TABLE 9 Persoz Hardness of
Activated Primer Compositions L to P Primer 3 Hours 1 Day L 34 86 M
39 93 N 41 85 O 35 46 P 30 61
[0127] TABLE-US-00020 TABLE 10 Fischer Hardness of Activated Primer
Compositions L to P Primer 1 day 7 days L 74 105 M 100 117 N 68 123
O 30.4 61 P 47 157
[0128] The above data in Table 9 shows that Primer Compositions L
to P have about the same Persoz Hardness after 3 hours but after
one day Primers L to N have a significant higher level of hardness
in comparison to Primers O and P that contained S Diol and did not
contain the polytrimethylene ether diol. The above data in Table 10
shows that Primer Compositions L to N have relatively high hardness
values after 1 day in comparison to Primer Compositions O and P
that contained S Diol and did not contain the polytrimethylene
ether diol. After 7 days, Primer Composition O that contained S
Diol had significantly lower hardness value comparison to the
Primer Compositions L, M, N, and P.
[0129] A set of panels primed with Primer Compositions L to P was
prepared as above. The panels were allowed to cure overnight at
about 24.degree. C. and 50% relative humidity and were then sanded
with 400 grit sandpaper and the resulting film build was about 4.0
to 4.5 mils (102 to 114 microns). Each of the panels was coated
with an un-activated red metallic base coat (described in Example
1). Each panel was top coated with a clear top coat (DuPont
ChromaClear.RTM. V-7500S described in Example 1) and cured.
[0130] Each of the above prepared panels was tested for chip
resistance using the Gravelometer test as described above. The
results are shown in Table 11 below. TABLE-US-00021 TABLE 11
Gravelometer Test Results 3 Pints Stones 1 Pint Stones Size of
Gravelometer Test Room Temp. Frozen Largest Chip Red Metallic Base
Coat Primer L 5 6 7.5 sq. mm Primer M 5 6 10 sq. mm Primer N 5 6 15
sq. mm Primer O 2 2 Not rated Primer P 2 2 Not rated
Primer L, the invention, Primer M and Primer N have similar
Gravelometer Chip ratings whereas Primers O and P have very low and
unacceptable Gravelometer Chip ratings. The size of the largest
chip is also a consideration. Primer L, the invention, has the
smallest size chips and is considered to have the best performance
in comparison to Primers M and N that had noticeably larger chip
sizes. Primers O and P were not rated for chip size since the
Gravelometer Chip ratings were poor.
* * * * *