Title: Coating compositions containing polyurethane dispersions and highly crosslinked polymer particles
Abstract: An aqueous polyurethane dispersion and thermosetting compositions containing them. The aqueous polyurethane dispersion includes an aqueous medium with dispersed polyurethane-acrylate particles, which include the reaction product obtained by polymerizing a pre-emulsion formed from hydrophobic polymerizable ethylenically unsaturated monomers, a crosslinking monomer, and an active hydrogen-containing polyurethane acrylate prepolymer, which is a reaction product obtained by reacting a polyol, a polymerizable, ethylenically unsaturated monomer containing at least one hydroxyl group, a compound that includes an alkyl group having at least one hydroxyl group and optionally a carboxylic acid group, and a polyisocyanate. The prepolymer includes at least 30 percent by weight of polyurethane acrylate prepolymers with at least one terminal ethylenic unsaturation at one end of the molecule, and at least one active hydrogen-containing group at the opposite end; and at least 10 percent by weight of prepolymers having at least one terminal ethylenic unsaturation at each end of the molecule.
Patent Number: 7,001,952 Issued on 02/21/2006 to Faler, et al.
| Inventors:
|
Faler; Dennis L. (Glenshaw, PA);
Barkac; Karen A. (North Huntingdon, PA);
Haley; M. Frank (Glenshaw, PA);
McHenry; Deena M. (Cranberry Township, PA);
Pagac; Edward S. (Portersville, PA);
Swarup; Shanti (Allison Park, PA);
Taylor; Cathy A. (Allison Park, PA);
Zezinka; Elizabeth A. (Cranberry Township, PA)
|
| Assignee:
|
PPG Industries Ohio, Inc. (Cleveland, OH)
|
| Appl. No.:
|
126903 |
| Filed:
|
April 19, 2002 |
| Current U.S. Class: |
525/185; 428/423.3; 428/425.8; 428/423.1; 525/123 |
| Current Intern'l Class: |
C08F 12/34 (20060101) |
| Field of Search: |
525/185,123
428/423.3,425.8,423.1
|
References Cited [Referenced By]
U.S. Patent Documents
| 3479328 | Nov., 1969 | Nordstrom.
| |
| 3799854 | Mar., 1974 | Jerabek.
| |
| 4001156 | Jan., 1977 | Bosso et al.
| |
| 4046729 | Sep., 1977 | Scriven et al.
| |
| 4147679 | Apr., 1979 | Scriven et al.
| |
| 4220679 | Sep., 1980 | Backhouse.
| |
| 4403003 | Sep., 1983 | Backhouse.
| |
| 4681811 | Jul., 1987 | Simpson et al.
| |
| 4705821 | Nov., 1987 | Ito et al.
| |
| 4728545 | Mar., 1988 | Kurauchi et al.
| |
| 4732790 | Mar., 1988 | Blackburn et al.
| |
| 4777213 | Oct., 1988 | Kanda et al.
| |
| 4798746 | Jan., 1989 | Claar et al.
| |
| 4880867 | Nov., 1989 | Gobel et al.
| |
| 5071904 | Dec., 1991 | Martin et al.
| |
| 5084541 | Jan., 1992 | Jacobs, III et al.
| |
| 5098947 | Mar., 1992 | Metzger et al.
| |
| 5102925 | Apr., 1992 | Suzuki et al.
| |
| 5196485 | Mar., 1993 | McMonigal et al.
| |
| 5212273 | May., 1993 | Das et al.
| |
| 5569715 | Oct., 1996 | Grandhee.
| |
| 5593733 | Jan., 1997 | Mayo.
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| 5663240 | Sep., 1997 | Simeone et al.
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| 5786420 | Jul., 1998 | Grandhee.
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| 5969030 | Oct., 1999 | Grandhee.
| |
| 6025031 | Feb., 2000 | Lettmann et al.
| |
| 6281272 | Aug., 2001 | Baldy et al.
| |
| 6291564 | Sep., 2001 | Faler et al.
| |
| 6329020 | Dec., 2001 | Patzschke et al.
| |
| Foreign Patent Documents |
| 0 216 479 | Apr., 1987 | EP.
| |
| 0 358 221 | Mar., 1990 | EP.
| |
| 95/09890 | Apr., 1995 | WO.
| |
Other References
Grant, R., Grant, C., eds., Grant & Hackh's Chemical Dictionary, 5th ed.,
McGraw-Hill Book Company, New York, 1987, p. 25.
Hong et al., "Core/Shell Acrylic Microgel as the Main Binder of Waterborne Metallic
Basecoats," Korea Polymer Journal, vol. 7, No. 4, pp. 213-222, 1999.
Odian, George, Principles of Polymerization, Second Edition, John Wiley
& Sons, New York, NY, pp. 319-331, 1983.
|
Primary Examiner: Bissett; Melanie
Attorney, Agent or Firm: Altman; Deborah M.
Claims
We claim:
1. A thermosetting composition comprising:
(I) a first reactant comprising reactive functional groups;
(II) a curing agent having functional groups reactive with the functional groups
of the first reactant in (I);
(III) a latex emulsion comprising crosslinked polymeric microparticles dispersed
in an aqueous continuous phase, the polymeric microparticles prepared from a monomer
mix comprised of:
(a) at least 20 weight percent of a crosslinking monomer having two or more groups
of reactive unsaturation and/or monomers having one or more functional groups capable
of reacting to form crosslinks after polymerization;
(b) at least 2 weight percent of one or more polymerizable ethylenically unsaturated
monomers having hydrophilic functional groups having the following structures (I)
and/or (II):
##STR8##
wherein A is selected from H and C
1-C
3 alkyl; B is selected
from —NR
1R
2, —OR
3 and —SR
4,
where R
1 and R
2 are independently selected from H, C
1-C
18
alkyl, C
1-C
18 alkylol and C
1-C
18 alkylamino,
R
3 and R
4 are independently selected from C
1-C
18
alkylol, C
1-C
18 alkylamino, —CH
2CH
2—(OCH
2CH
2)
n—OH
where n is 0 to 30, and, —CH
2CH
2—(OC(CH
3)HCH
2)
m—OH
where m is 0 to 30, D is selected from H and C
1-C
3 alkyl;
and E is selected from —CH
2CHOHCH
2OH, C
1-C
18
alkylol, —CH
2CH
2—(OCH
2CH
2)
n—OH
where n is 0 to 30, and —CH
2CH
2—(OC(CH
3)
HCH
2)
m—OH where m is 0 to 30; and
(c) optionally, the balance comprised of one or more polymerizable ethylenically
unsaturated monomers, wherein (a), (b) and (c) are different from each other; and
(IV) an aqueous polyurethane dispersion, comprising polyurethane-acrylate particles
dispersed in an aqueous medium, said particles comprising the reaction product
obtained by polymerizing the components of a pre-emulsion formed from:
(A) an active hydrogen-containing polyurethane acrylate prepolymer, comprising
a reaction product obtained by reacting:
(i) a polyol;
(ii) a polymerizable, ethylenically unsaturated monomer containing at least one
hydroxyl group;
(iii) a compound comprising a C
1-C
30 alkyl group having
at least two active hydrogen groups selected from carboxylic acid groups and hydroxyl
groups, wherein at least one active hydrogen group is a hydroxyl group; and
(iv) a polyisocyanate;
(B) one or more hydrophobic polymerizable ethylenically unsaturated monomers; and
(C) a crosslinking monomer;
wherein the active hydrogen functional polyurethane acrylate prepolymer of (A)
includes at least 30 percent by weight of polyurethane acrylate prepolymer comprising
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation, at one end of the molecule and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
the polyurethane acrylate prepolymer comprising one or more prepolymers having
at least one terminal polymerizable site of ethylenic unsaturation at each end
of the molecule.
2. The thermosetting composition of claim 1, wherein the polyol is one or more
polyols selected from the group consisting of polyetherpolyols, polyesterpolyols
and acrylic polyols.
3. The thermosetting composition of claim 2, wherein the polyol is one or more
polyetherpolyols comprising the following formula (I):
##STR9##
wherein R
1 is H or C
1-C
5 alkyl including mixed
substituents, n is from 1 to 200 and m is from 1 to 5.
4. The thermosetting composition of claim 2, wherein the polyol is one or more
polyetherpolyol selected from the group consisting of poly(oxytetramethylene) glycols,
poly(oxyethylene) glycols, poly(oxy-1,2-propylene) glycols, the reaction products
of ethylene glycol with a mixture of 1,2-propylene oxide and ethylene oxide, poly(tetrahydrofuran),
the reaction products obtained by the polymerization of ethylene oxide, propylene
oxide and tetrahydrofuran, 1,6-hexanediol, trimethylolpropane, sorbitol and pentaerythritol.
5. The thermosetting composition of claim 1, wherein the polymerizable ethylenically
unsaturated monomer containing at least one hydroxyl group is one or more monomers
comprising the formula
##STR10##
where R
2 is H or C
1-C
4 alkyl and R
3 is
selected from —(CHR
4)
p—OH, —CH
2CH
2—(O—CH
2—CHR
4)
p—OH,
—CH
2—CHOH—CH
2—O—CO—CR
5R
6R
7,
and —CH
2—CHR
4—O—CH
2—CHOH—CH
2—O—CO—CR
5R
6R
7
where R
4 is H or C
1-C
4 alkyl, R
5,
R
6, and R
7 are H or C
1-C
20 linear or
branched alkyl and p is an integer from 0 to 20.
6. The thermosetting composition of claim 1, wherein the polymerizable ethylenically
unsaturated monomer containing at least one hydroxyl group (ii) comprises one or
more monomers selected from the group consisting of hydroxyethyl(meth)acrylate,
hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, polyethyleneglycol ester
of (meth)acrylic acid, polypropyleneglycol ester of (meth)acrylic acid, the reaction
product of (meth)acrylic acid and the glycidyl ester of versatic acid, the reaction
product of hydroxyethyl(meth)acrylate and the glycidyl ester of versatic acid,
and the reaction product of hydroxypropyl(meth)acrylate and the glycidyl ester
of versatic acid.
7. The thermosetting composition of claim 1, wherein the compound (iii) comprises
a compound selected from the group consisting of dimethylol proprionic acid and
12-hydroxystearic acid 12-hydroxystearic acid.
8. The thermosetting composition of claim 1, wherein the polyisocyanate (iv)
comprises one or more of an aliphatic and an aromatic polyisocyanate.
9. The thermosetting composition of claim 1, wherein the polyisocyanate (iv)
comprises one or more selected from the group consisting of isophorone diisocyanate,
4,4′-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene
diisocyanate, tolylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene
diisocyanate, 1,4-cyclohexyl diisocyanate, alpha, alpha-xylylene diisocyanate,
4,4′-methylene-bis(cyclohexyl isocyanate), 1,2,4-benzene triisocyanate,
and polymethylene polyphenyl isocyanate.
10. The thermosetting composition of claim 1, wherein the polyurethane-acrylate
dispersed particles of the polyurethane dispersion has an ordered structure wherein
greater than 50 percent by weight of an outer portion of the dispersed particle
near the aqueous medium comprises residues from the active hydrogen functional
polyurethane acrylate prepolymer comprising prepolymers with a polymerizable double
bond at one end of the prepolymer and an active hydrogen containing group at the
other end of the prepolymer and an interior portion of the particle comprises greater
than 50 percent by weight of the reaction product of the one or more hydrophobic
polymerizable ethylenically unsaturated monomers (B); and crosslinking monomer (C).
11. The thermosetting composition of claim 1, wherein each of the crosslinking
monomer (a) and the crosslinking monomer (C) have two or more sites of polymerizable
ethylenic unsaturation.
12. The thermosetting composition of claim 1, wherein each of the crosslinking
monomer (a) and the crosslinking monomer (C) comprises one or more monomers selected
from the group consisting of ethylene glycol di(meth)acrylate, triethylene glycol
di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl
glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol
di(meth)acrylate, glycerol allyloxy di(meth)acrylate, 1,1,1-tris(hydroxymethyl)ethane
di(meth)acrylate, 1,1,1-tris(hydroxymethyl)ethane tri(meth)acrylate, 1,1,1-tris(hydroxymethyl)propane
di(meth)acrylate, 1,1,1-tris(hydroxymethyl)propane tri(meth)acrylate, triallyl
cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl phthalate, diallyl
terephthalate, divinyl benzene, methylol (meth)acrylamide, triallylamine, and methylenebis
(meth) acrylamide.
13. The thermosetting composition of claim 1, wherein each of the polymerizable
ethylenically unsaturated monomer (c) and the one or more hydrophobic polymerizable
ethylenically unsaturated monomers (B) comprises one or more monomers selected
from the group consisting of methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,
N-butyl(meth)acrylate, t-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isobornyl
(meth)acrylate, glycidyl (meth)acrylate, N-butoxy methyl (meth)acrylamide, styrene,
(meth)acrylonitrile, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and 3,3,5-trimethylcyclohexyl (meth)acrylate.
14. The thermosetting composition of claim 1, wherein the ethylenically unsaturated
monomer having hydrophilic functional groups (b) comprises one or more monomers
selected from the group consisting of (meth)acrylamide, hydroxyethyl (meth)acrylate,
hydroxypropyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate.
15. The thermosetting composition of claim 1, wherein the average particle size
of the polymeric microparticles of (III) ranges from 0.01 to 1 microns.
16. The thermosetting composition of claim 1, wherein the average particle size
of the polyurethane-acrylate particles of (IV) ranges from 50 nm to 500 nanometers.
17. The thermosetting composition of claim 1, wherein said thermosetting composition
is a coating composition.
18. The thermosetting composition of claim 1, wherein the thermosetting composition
is substantially free of polymeric emulsifiers and/or protective colloids.
19. The thermosetting composition of claim 1, wherein the functional groups of
the first reactant (I) are selected from the group consisting of epoxy, carboxylic
acid, hydroxy, amide, oxazoline, aceto acetate, isocyanate, methylol, amino, methylol
ether, carbamate, and mixtures thereof.
20. The thermosetting composition of claim 1, wherein the functional groups of
curing agent (II) are selected from the group consisting of epoxy, carboxylic acid,
hydroxy, isocyanate, capped isocyanate, amine, methylol, methylol ether, beta-hydroxyalkylamide,
and mixtures thereof.
21. The thermosetting composition of claim 1, wherein the functional groups of
crosslinking agent (II) are different from and reactive with those of the first
reactant (I).
22. The thermosetting composition of claim 1, wherein the first reactant (I)
is a polymer containing hydroxyl functional groups, and the curing agent (II) comprises
one or more materials selected from polyamines, aminoplast resins and polyisocyanates.
23. A coated substrate comprising:
(a) a substrate; and
(b) the thermosetting composition of claim 1 over at least a portion of the substrate (a).
24. The coated substrate of claim 23, wherein the thermosetting composition further
comprises one or more effect pigments.
25. The coated substrate of claim 24, wherein the thermosetting composition when
cured has a Flop Index of at least 10 and shortwave values of no more than 14.
26. A substrate coated by a method comprising:
(A) applying a thermosetting composition over at least a portion of the substrate;
(B) coalescing said thermosetting composition to form a substantially continuous
film on the substrate; and
(D) curing the thermosetting composition, wherein the thermosetting composition comprises:
(I) a first reactant comprising reactive functional groups;
(II) a curing agent having functional groups reactive with the functional groups
of the first reactant in (I);
(III) a latex emulsion comprising crosslinked polymeric microparticles dispersed
in an aqueous continuous phase, the polymeric microparticles prepared from a monomer
mix comprised of:
(a) at least 20 weight percent of a crosslinking monomer having two or more sites
of reactive unsaturation and/or monomers having one or more functional groups capable
of reacting to form crosslinks after polymerization;
(b) at least 2 weight percent of one or more polymerizable ethylenically unsaturated
monomers having hydrophilic functional groups; and
(c) optionally, the balance comprised of one or more polymerizable ethylenically
unsaturated monomers, wherein (a), (b) and (c) are different from each other; and
(IV) an aqueous polyurethane dispersion, comprising polyurethane-acrylate particles
dispersed in an aqueous medium, said particles comprising the reaction product
obtained by polymerizing the components of a pre-emulsion formed from:
(A) an active hydrogen-containing functional polyurethane acrylate prepolymer,
comprising a reaction product obtained by reacting:
(i) a polyol;
(ii) a polymerizable ethylenically unsaturated monomer containing at least one
hydroxyl group;
(iii) a compound comprising a C
1-C
30 alkyl group comprising
at least two active hydrogen groups selected from carboxylic acid groups and hydroxyl
groups, wherein at least one active hydrogen group is a hydroxyl group; and
(iv) a polyisocyanate;
(B) one or more hydrophobic polymerizable ethylenically unsaturated monomers; and
(C) a crosslinking monomer;
wherein the active hydrogen functional polyurethane acrylate prepolymer of (A)
includes at least 30 percent by weight of polyurethane acrylate prepolymer comprising
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation, at one end of the molecule and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
the polyurethane acrylate prepolymer comprising one or more prepolymers having
at least one terminal polymerizable site of ethylenic unsaturation at each end
of the molecule.
27. The coated substrate of claim 26, wherein the thermosetting composition further
comprises one or more effect pigments.
28. The coated substrate of claim 27, wherein the thermosetting composition when
cured has a Flop index of at least 10 and shortwave values of no more than 14.
29. A multi-layer composite coating comprising:
(A) a base coat layer deposited from an effect pigment-containing base coat composition,
wherein said base coat composition comprises:
(I) a first reactant comprising reactive functional groups;
(II) a curing agent having functional groups reactive with the functional groups
of the first reactant in (I);
(III) a latex emulsion comprising crosslinked polymeric microparticles dispersed
in an aqueous continuous phase, the polymeric microparticles prepared from a monomer
mix comprised of:
(a) at least 20 weight percent of a crosslinking monomer having two or more groups
of reactive unsaturation and/or monomers having one or more functional groups capable
of reacting to form crosslinks after polymerization;
(b) at least 2 weight percent of one or more polymerizable ethylenically unsaturated
monomers having hydrophilic functional groups having the following structures (I)
and/or (II):
##STR11##
wherein A is selected from H and C
1-C
3 alkyl; B is
selected from —NR
1R
2, —OR
3 and —SR
4,
where R
1 and R
2 are independently selected from H, C
1-C
18
alkyl, C
1-C
18 alkylol and C
1-C
18 alkylamino,
R
3 and R
4 are independently selected from C
1-C
18
alkylol, C
1-C
18 alkylamino, —CH
2CH
2—(OCH
2CH
2)
n—OH
where n is 0 to 30, and, —CH
2CH
2—(OC(CH
3)HCH
2)
m—OH
where m is 0 to 30, D is selected from H and C
1-C
3 alkyl;
and E is selected from —CH
2CHOHCH
2OH, C
1-C
18
alkylol, —CH
2CH
2—(OCH
2CH
2)
m—OH
where n is 0 to 30, and —CH
2CH
2—(OC(CH
3)HCH
2)
n—OH
where m is 0 to 30; and
(c) optionally, the balance comprised of one or more polymerizable ethylenically
unsaturated monomers, wherein (a), (b) and (c) are different from each other; and
(IV) an aqueous polyurethane dispersion, comprising polyurethane-acrylate particles
dispersed in an aqueous medium, said particles comprising the reaction product
obtained by polymerizing the components of a pre-emulsion formed from:
(A) an active hydrogen-containing polyurethane acrylate prepolymer, comprising
a reaction product obtained by reacting:
(i) a polyol;
(ii) a polymerizable ethylenically unsaturated monomer containing at least one
hydroxyl group;
(iii) a compound comprising a C
1-C
30 alkyl group comprising
at least two active hydrogen groups selected from carboxylic acid groups and hydroxyl
groups, wherein at least one active hydrogen group is a hydroxyl group; and
(iv) a polyisocyanate;
(B) one or more hydrophobic polymerizable ethylenically unsaturated monomers; and
(C) a crosslinking monomer;
wherein the active hydrogen functional polyurethane acrylate prepolymer of (A)
includes at least 30 percent by weight of polyurethane acrylate prepolymer comprising
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation at one end of the molecule and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
the polyurethane acrylate prepolymer comprising one or more prepolymers having
at least one terminal polymerizable site of ethylenic unsaturation at each end
of the molecule; and
(B) a substantially pigment free top coat layer deposited over at least a portion
of said base coat layer from a substantially pigment free top coat composition.
30. The multi-layer composite coating of claim 29, wherein the polyol is one
or more polyols selected from the group consisting of polyetherpolyols, polyesterpolyols
and acrylic polyols.
31. The multi-layer composite coating of claim 30, wherein the polyol is one
or more polyetherpolyols comprising the following formula (I):
##STR12##
wherein R
1 is H or C
1-C
5 alkyl including mixed
substituents, n is from 0 to 200 and m is from 1 to 5.
32. The multi-layer composite coating of claim 29, wherein the polyol is one
or more polyetherpolyols selected from the group consisting of poly(oxytetramethylene)
glycols, poly(oxyethylene) glycols, poly(oxy-1,2-propylene) glycols, the reaction
products of ethylene glycol with a mixture of 1,2-propylene oxide and ethylene
oxide, poly(tetrahydrofuran), the reaction products obtained by the polymerization
of ethylene oxide, propylene oxide and tetrahydrofuran, 1,6-hexanediol, trimethylolpropane,
sorbitol and pentaerythritol.
33. The multi-layer composite coating of claim 29, wherein the polymerizable
ethylenically unsaturated monomer containing at least one hydroxyl group is one
or more monomers comprising the formula
##STR13##
where R
2 is H or C
1-C
4 alkyl and R
3 is
selected from —(CHR
4)
p—OH, —CH
2CH
2—(O—CH
2—CHR
4)
p—OH,
—CH
2—CHOH—CH
2—O—CO—CR
5R
6R
7,
and —CH
2—CHR
4—O—CH
2—CHOH—CH
2—O—CO—CR
5R
6R
7
where R
4 is H or C
1-C
4 alkyl, R
5,
R
6, and R
7 are H or C
1-C
20 linear or
branched alkyl and p is an integer from 0 to 20.
34. The multi-layer composite coating of claim 29, wherein the polymerizable
ethylenically unsaturated monomer containing at least one hydroxyl group (ii) comprises
one or more monomers selected from the group consisting of hydroxyethyl(meth)acrylate,
hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, polyethyleneglycol ester
of (meth)acrylic acid, polypropyleneglycol ester of (meth)acrylic acid, the reaction
product of (meth)acrylic acid and the glycidyl ester of versatic acid, the reaction
product of hydroxyethyl(meth)acrylate and the glycidyl ester of versatic acid,
and the reaction product of hydroxypropyl(meth)acrylate and the glycidyl ester
of versatic acid.
35. The multi-layer composite coating of claim 29, wherein the compound (iii)
comprises a compound selected from the group consisting of dimethylol proprionic
acid and 12-hydroxystearic acid.
36. The multi-layer composite coating of claim 29, wherein the polyisocyanate
(iv) comprises one or more of an aliphatic and an aromatic polyisocyanate.
37. The multi-layer composite coating of claim 29, wherein the polyisocyanate
(iv) comprises one or more selected from the group consisting of isophorone diisocyanate,
4,4′-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene
diisocyanate, tolylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene
diisocyanate, 1,4-cyclohexyl diisocyanate, alpha, alpha-xylylene diisocyanate,
4,4′-methylene-bis(cyclohexyl isocyanate), 1,2,4-benzene triisocyanate,
and polymethylene polyphenyl isocyanate.
38. The multi-layer composite coating of claim 29, wherein the polyurethane-acrylate
dispersed particles of the polyurethane dispersion have an ordered structure wherein
greater than 50 percent by weight of an outer portion of the dispersed particle
near the aqueous medium comprises residues from the active hydrogen functional
polyurethane acrylate prepolymer comprising prepolymers with a polymerizable double
bond at one end of the prepolymer and an active hydrogen containing group at the
other end of the prepolymer and an interior portion of the particle comprises greater
than 50 percent by weight of the reaction product of the one or more hydrophobic
polymerizable ethylenically unsaturated monomers (B); and crosslinking monomer (C).
39. The multi-layer composite coating of claim 29, wherein each of the crosslinking
monomer (a) and the crosslinking monomer (C) each have two or more sites of polymerizable
ethylenic unsaturation.
40. The multi-layer composite coating of claim 29, wherein each of the crosslinking
monomer (a) and the crosslinking monomer (C) comprises one or more monomers selected
from the group consisting of ethylene glycol di(meth)acrylate, triethylene glycol
d i(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl
glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol
di(meth)acrylate, glycerol allyloxy di(meth)acrylate, 1,1,1 -tris(hydroxymethyl)ethane
di(meth)acrylate, 1,1,1-tris(hydroxymethyl)ethane tri(meth)acrylate, 1,1,1-tris(hydroxymethyl)propane
di(meth)acrylate, 1,1,1-tris(hydroxymethyl)propane tri(meth)acrylate, triallyl
cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl phthalate, diallyl
terephthalate, divinyl benzene, methylol (meth)acrylamide, triallylamine, and methylenebis
(meth) acrylamide.
41. The multi-layer composite coating of claim 29, wherein each of the polymerizable
ethylenically unsaturated monomer (c) and the one or more hydrophobic polymerizable
ethylenically unsaturated monomers (B) comprises one or more monomers selected
from the group consisting of methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,
N-butyl(meth)acrylate, t-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isobornyl
(meth)acrylate, glycidyl (meth)acrylate, N-butoxy methyl (meth)acrylamide, styrene,
(meth)acrylonitrile, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and 3,3,5-trimethylcyclohexyl (meth)acrylate.
42. The multi-layer composite coating of claim 29, wherein the ethylenically
unsaturated monomer having hydrophilic functional groups (b) comprises one or more
monomers selected from the group consisting of (meth)acrylamide, hydroxyethyl (meth)acrylate,
hydroxypropyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate.
43. The multi-layer composite coating of claim 29, wherein the average particle
size of the polymeric microparticles of (III) ranges from 0.01 to 1 microns.
44. The multi-layer composite coating of claim 29, wherein the average particle
size of the polyurethane-acrylate particles of (IV) ranges from 50 nm to 500 nanometers.
45. The multi-layer composite coating of claim 29, wherein said thermosetting
composition is a coating composition.
46. The multi-layer composite coating of claim 29, wherein the thermosetting
composition is substantially free of polymeric emulsifiers and/or protective colloids.
47. The multi-layer composite coating of claim 29, wherein the functional groups
of the first reactant (I) are selected from the group consisting of epoxy, carboxylic
acid, hydroxy, amide, oxazoline, aceto acetate, isocyanate, methylol, amino, methylol
ether, carbamate, and mixtures thereof.
48. The multi-layer composite coating of claim 29, wherein the functional groups
of curing agent (II) are selected from the group consisting of epoxy, carboxylic
acid, hydroxy, isocyanate, capped isocyanate, amine, methylol, methylol ether,
beta-hydroxyalkylamide, and mixtures thereof.
49. The multi-layer composite coating of claim 29, wherein the functional groups
of crosslinking agent (II) are different from and reactive with those of the first
reactant (I).
50. The multi-layer composite coating of claim 29, wherein the first reactant
(I) is a polymer containing hydroxyl functional groups, and the curing agent (II)
comprises one or more materials selected from polyamines, aminoplast resins and polyisocyanates.
51. A coated substrate comprising:
(A) a substrate, and
(B) the multi-layer composite coating composition of claim 29 over at least a
portion of the substrate (A).
52. The coated substrate of claim 51, wherein the thermosetting composition further
comprises one or more effect pigments.
53. The coated substrate of claim 51, wherein the substrate is selected from
a metallic substrate, an elastomeric substrate, and combinations thereof.
54. The coated substrate of claim 52, wherein the thermosetting composition when
cured has a Flop index of at least 10 and shortwave values of no more than 14.
55. A multi-layer composite coating comprising:
(A) a base coat layer deposited from a base coat composition, wherein said base
coat composition comprises:
(I) a first reactant comprising reactive functional groups;
(II) a curing agent having functional groups reactive with the functional groups
of the first reactant in (I);
(III) a latex emulsion comprising crosslinked polymeric microparticles dispersed
in an aqueous continuous phase, the polymeric microparticles prepared from a monomer
mix comprised of:
(a) at least 20 weight percent of a crosslinking monomer having two or more groups
of reactive unsaturation and/or monomers having one or more functional groups capable
of reacting to form crosslinks after polymerization;
(b) at least 2 weight percent of one or more polymerizable ethylenically unsaturated
monomers having hydrophilic functional groups having the following structures (I)
and/or (II):
##STR14##
wherein A is selected from H and C
1-C
3 alkyl; B is
selected from —NR
1R
2, —OR
3 and —SR
4,
where R
1 and R
2 are independently selected from H, C
1-C
18
alkyl, C
1-C
18 alkylol and C
1-C
18 alkylamino,
R
3 and R
4 are independently selected from C
1-C
18
alkylol, C
1-C
18 alkylamino, —CH
2CH
2—(OCH
2CH
2)
n—OH
where n is 0 to 30, and, —CH
2CH
2—(OC(CH
3)HCH
2)
m—OH
where m is 0 to 30, D is selected from H and C
1-C
3 alkyl;
and E is selected from —CH
2CHOHCH
2OH, C
1-C
18
alkylol, —CH
2CH
2—(OCH
2CH
2)
m—OH
where n is 0 to 30, and —CH
2CH
2—(OC(CH
3)HCH
2)
n—OH
where m is 0 to 30; and
(c) optionally, the balance comprised of one or more polymerizable ethylenically
unsaturated monomers, wherein (a), (b) and (c) are different from each other; and
(IV) an aqueous polyurethane dispersion, comprising polyurethane-acrylate particles
dispersed in an aqueous medium, said particles comprising the reaction product
obtained by polymerizing the components of a pre-emulsion formed from:
(A) an active hydrogen-containing polyurethane acrylate prepolymer, comprising
a reaction product obtained by reacting:
(i) a polyol;
(ii) a polymerizable ethylenically unsaturated monomer containing at least one
hydroxyl group;
(iii) a compound comprising a C
1-C
30 alkyl group comprising
at least two active hydrogen groups selected from carboxylic acid groups and hydroxyl
groups, wherein at least one active hydrogen group is a hydroxyl group; and
(iv) a polyisocyanate;
(B) one or more hydrophobic polymerizable ethylenically unsaturated monomers; and
(C) a crosslinking monomer;
wherein the active hydrogen functional polyurethane acrylate prepolymer of (A)
includes at least 30 percent by weight of polyurethane acrylate prepolymer comprising
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation at one end of the molecule and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
the polyurethane acrylate prepolymer comprising one or more prepolymers having
at least one terminal polymerizable site of ethylenic unsaturation at each end
of the molecule; and
(B) a substantially pigment free top coat layer wherein said top coat layer comprises
a substantially pigment free powder coating composition deposited over at least
a portion of said base coat layer from the powder coating composition.
56. The multi-layer composite coating of claim 55, wherein the aqueous polyurethane
dispersion (iv) is present in the base coat composition of (A) in an amount sufficient
to provide a multi-layer composite coating having a b value, as measured according
to the L*a*b color space theory, which is at least 0.2 less than the b value of
a multi-layer composite coating in which the base coat composition does not contain
the aqueous polyurethane dispersion (iv).
57. A thermosetting composition comprising:
(I) a first reactant comprising reactive functional groups;
(II) a curing agent having functional groups reactive with the functional groups
of the first reactant in (I);
(III) a latex emulsion comprising crosslinked polymeric microparticles dispersed
in an aqueous continuous phase, the polymeric microparticles prepared from a monomer
mix comprised of:
(a) at least 20 weight percent of a crosslinking monomer having two or more groups
of reactive unsaturation and/or monomers having one or more functional groups capable
of reacting to form crosslinks after polymerization;
(b) at least 2 weight percent of one or more polymerizable ethylenically unsaturated
monomers having hydrophilic functional groups selected from the group consisting
of(meth)acrylamide, hydroxyethy(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl
(meth)acrylate, allyl glycerol ether, methallyl glycerol ether and polyethyleneoxide
allyl ether; and
(c) optionally, the balance comprised of one or more polymerizable ethylenically
unsaturated monomers, wherein (a), (b) and (c) are different from each other; and
(IV) an aqueous polyurethane dispersion, comprising polyurethane-acrylate particles
dispersed in an aqueous medium, said particles comprising the reaction product
obtained by polymerizing the components of a pre-emulsion formed from:
(A) an active hydrogen-containing polyurethane acrylate prepolymer, comprising
a reaction product obtained by reacting:
(i) a polyol;
(ii) a polymerizable, ethylenically unsaturated monomer containing at least one
hydroxyl group;
(iii) a compound comprising a C
1-C
30 alkyl group having
at least two active hydrogen groups selected from carboxylic acid groups and hydroxyl
groups, wherein at least one active hydrogen group is a hydroxyl group; and
(iv) a polyisocyanate;
(B) one or more hydrophobic polymerizable ethylenically unsaturated monomers; and
(C) a crosslinking monomer;
wherein the active hydrogen functional polyurethane acrylate prepolymer of (A)
includes at least 30 percent by weight of polyurethane acrylate prepolymer comprising
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation, at one end of the molecule and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
the polyurethane acrylate prepolymer comprising one or more prepolymers having
at least one terminal polymerizable site of ethylenic unsaturation at each end
of the molecule.
Description
This application is related to copending U.S. patent application Ser. No. 10/126,137
entitled "Highly Crosslinked Polymer Particles and Coating Compositions Containing
the Same" of Shanti Swarup et al., also filed Apr, 19, 2002.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aqueous polyurethane dispersions and thermosetting
compositions containing polyurethane dispersions and dispersions of crosslinked
polymeric microparticles. More particularly, the present invention is directed
to coating compositions containing aqueous polyurethane dispersions and crosslinked
polymeric microparticles used in multi-component composite coating compositions
such as primers, pigmented or colored basecoats, and/or transparent topcoats which
provide good smoothness and appearance.
2. Background of the Invention
Over the past decade, there has been a concerted effort to reduce atmospheric
pollution caused by volatile solvents which are emitted during painting processes.
However, it is often difficult to achieve high quality, smooth coating finishes,
such as are required in the automotive industry, without the inclusion of organic
solvents which contribute greatly to flow and leveling of a coating.
Due to environmental concerns, volatile organic compounds ("VOCs") and/or hazardous
air pollutants ("HAPs") have come under strict regulation by the government. Therefore,
one of the major goals of the coatings industry is to minimize the use of organic
solvents by formulating waterborne coating compositions which provide a smooth,
high gloss appearance, as well as good physical properties including resistance
to acid rain. Unfortunately, many waterborne coating compositions, particularly
those containing metallic flake pigments, do not provide acceptable appearance
properties because, inter alia, they can deposit as a rough film under conditions
of low humidity. Although smooth films can be obtained if the humidity is controlled
within narrow limits, this often is not possible in industrial applications without
incurring considerable expense.
The paint application process in an automotive industrial paint shop consists
of four steps: storage in a tank; circulation in pipelines; spraying via a bell
and/or a spray gun nozzle; and film formation on the surface of the substrate.
The shear rates active on the paint in each of the steps are quite different and
require varying paint rheological properties for each step. To design proper paint
viscosity in waterborne automotive coatings, a distinct rheology profile is needed
to provide good sprayability, sag resistance and levelling properties simultaneously.
In basecoat compositions, shear thinning flow behavior is usually preferred. In
many cases, special rheology control agents are used in coating formulations to
provide the desired flow behavior.
Microgels or crosslinked microparticles have been used in the paint industry
to improve the rheological properties of coating compositions as well as the physical
properties of the coating, such as tensile strength, solvent resistance, and gas
permeability. A particular goal has been to provide good sprayability, sag resistance
and leveling properties simultaneously. In basecoat paints, proper shear thinning
flow behavior is required to achieve this goal.
Basecoat coating compositions containing "effect" or reflective pigments,
such as metallic flake pigments e.g., aluminum flake and micaceous pigments have
increased in popularity in recent years because of the "glamorous" and distinctive
chromic effects they provide. In such coatings, orientation of the aluminum flakes
parallel to the surface of the substrate produces a unique metallic effect often
referred to as "flip-flop" or "flop". A higher flop effect provides a more desired,
brighter metallic appearance having a high level of color transition or "travel"
with changes in viewing angle. The rheological properties of the coating composition,
especially as affected by microgels, can greatly impact the flop property by promoting
proper metallic flake orientation.
U.S. Pat. No. 6,291,564 to Faler, et al. discloses an aqueous coating composition
that includes a crosslinkable film-forming resin and polymeric microparticles.
However, under certain application conditions, the coating compositions can provide
less than optimal appearance properties when metallic flake pigments are included
in the coating composition. For example, the coatings can be prone to mottling
(that is, an uneven distribution of metal flakes in the cured film) and sometimes
do not have a smooth appearance. Furthermore, the resulting aqueous coating may
include an unacceptable level of HAPs in the form of organic solvents.
Hong et al., "Core/Shell Acrylic Microgel as the Main Binder of Waterborne Metalic
Basecoats",
Korea Polymer Journal, Vol. 7, No. 4, pp 213-222 (1999) discloses
an alkali swellable core/shell acrylic microgel emulsions having a hydrophobic
core and a shell that included low levels of 2-hydroxyethyl acrylate and/or methacrylic
acid as well as up to 8% crosslinking monomer content. The microgels provide pseudoplastic
or shear thinning behavior in aqueous metallic basecoats. Addition of an alkali
is required to promote swelling of the microgel, which can be problematic in achieving
reproducible rheological properties.
Polymeric microparticles may be prepared by latex emulsion polymerization,
where a suitable crosslinking monomer is included in the dispersed, water insoluble
monomer phase. The macroscopic interactions and kinetics of latex emulsion polymerizations
are generally described by the Smith-Ewart model. In the latex emulsion polymerization
technique, water-insoluble or slightly water-soluble monomers are added to an aqueous
continuous phase and form dispersed monomer droplets. A very small fraction of
the monomers go into solution and form monomer micelles. A free radical source
is added to the emulsion and polymerization is initiated within the micelles, to
which additional monomer is fed from the monomer droplets. The end result is polymer
particles dispersed in an aqueous continuous phase. See
Principles of Polymerization,
Second Edition, Odian, Wiley-Interscience, pp. 319-331 (1983).
When water-soluble monomers are incorporated into the monomer mix in a latex
emulsion polymerization process, initiation of polymerization in the aqueous continuous
phase can result. When water-soluble monomers are polymerized in the aqueous continuous
phase of a latex emulsion polymerization, the resulting polymer typically ranges
from grit or coagulum to a thick solution or gel, rather than a dispersed polymer
particle. The risk of such adverse results has limited the use of water-soluble
monomers in latex emulsion polymerization processes.
U.S. Pat. No. 5,102,925 to Suzuki, et al. discloses an air-drying paint composition
that includes internally cross-linked polymer microparticles, a film-forming resin
and a volatile organic solvent. The use of thermosetting resins in the paint composition
is not disclosed. The microparticles are produced by emulsion polymerization of
ethylenically unsaturated monomers and at least one crosslinking monomer in the
presence of an emulsifier.
U.S. Pat. No. 4,705,821 to Ito, et al. discloses an anticorrosive metal surface
pretreating composition that includes an aqueous emulsion of hard polymer microparticles
and a water soluble chromium compound. The polymer microparticles are prepared
by emulsion polymerization of mono-unsaturated monomers and polyfunctional monomers.
European Patent Application No. 0 358 221 to Grutter et al. discloses electrodeposition
coatings that include an aqueous dispersion of a cathodic or anodic deposition
resin and polymer microparticles. The polymer microparticles include 0.1 to 5%,
less than 2% by example, of monomers containing hydrophilic groups.
Generally, the known microgel thickeners used in aqueous basecoat coating
compositions are deficient in that the resultant basecoatings can be susceptible
to penetration by a solvent-based clear topcoat into the cured basecoat (commonly
referred to as "soak in" or "strike in") and typically are only effective with
certain limited clearcoats. Further, additional rheology modifiers or thickeners
are often required to ensure a desired rheological profile for the cured coating
composition, which also typically include HAPs solvents. Even with the additional
rheology modifiers, these coating compositions can exhibit poor flow properties
resulting in spray application difficulties and/or sagging upon application; moreover,
these coatings can exhibit mottling, and/or a rough appearance.
In order to overcome the surface roughness of the coating, dispersions of hydrophobic
polyurethanes have been added to coating compositions containing microgel thickeners
in order to provide a smoother appearance. Polyurethane dispersions have been used
in aqueous coating compositions as for example in U.S. Pat. No. 5,071,904 to Martin
et al., which discloses a waterborne coating composition that includes a dispersion
of polymeric microparticles of a hydrophobic polyurethane and is adapted to be
chemically bound into the cured coating composition. The aqueous medium of the
microparticle dispersion is substantially free of water-soluble polymer.
U.S. Pat. No. 4,880,867 to Gobel et al. discloses an aqueous coating composition
that includes a film-forming material based on water dilutable binders which are
a mixture of a hydroxyl group-containing polymer resin; a chain extended polyurethane
dispersion and pigments.
U.S. Pat. No. 5,569,715 to Grandhee and U.S. Pat. No. 6,025,031 to Lettman et
al. disclose coating compositions that include an aqueous dispersion, prepared
in a single- or multi-stage method, of a hydrophilicized polymer resin based on
a hydrophobic polyurethane resin. The coating composition is useful for the finishing
of automobile bodies and plastics parts and for automotive refinishing.
U.S. Pat. No. 6,281,272 to Baldy et al. and U.S. Pat. No. 6,291,564 to Faler
et al. disclose waterborne coating compositions that include a dispersion of polymeric
microparticles. The microparticles are prepared by mixing monomer(s) and a chain-extended
hydrophobic polyurethane together to form a pre-emulsion and particularized into
microparticles by subjecting the pre-emulsion to high-shear stress using a homogenizer.
The ethylenically unsaturated monomer(s) are then polymerized to form polymeric
microparticles which are stably dispersed in the aqueous medium.
The polyurethane dispersions are useful for providing smoothness to the cured
coating composition. However, the brightness of the coating is typically degraded,
i.e., a coating containing the hydrophilic polyurethane dispersion will not be
as bright as a coating that does not contain the hydrophilic polyurethane dispersion.
This is especially true when effect pigments, such as those based on metal flakes,
are used in the coating composition.
It would be desirable to provide a thermosetting waterborne coating composition
that contains metallic flake pigments, which is useful as an original finish, contains
low or no VOC or HAP materials, and has an optimal shear thinning flow profile
while providing desirable appearance properties, to yield a smooth appearance,
with high flip-flop, and no mottling.
SUMMARY OF THE INVENTION
The present invention is directed to an aqueous polyurethane dispersion that
includes polyurethane-acrylate particles dispersed in an aqueous medium. The particles
include the reaction product obtained by polymerizing the components of a pre-emulsion
formed from:
- (A) an active hydrogen-containing polyurethane acrylate prepolymer,
comprising a reaction product obtained by reacting:
- (i) a polyol;
- (ii) a polymerizable, ethylenically unsaturated monomer containing
at least one hydroxyl group;
- (iii) a compound comprising a C1-C30 alkyl
group having at least two active hydrogen groups selected from carboxylic acid
groups and hydroxyl groups, wherein at least one active hydrogen group is a hydroxyl
group; and
- (iv) a polyisocyanate;
- (B) one or more hydrophobic polymerizable ethylenically unsaturated
monomers; and
- (C) a crosslinking monomer.
The active hydrogen functional polyurethane acrylate prepolymer of (A) includes
at least 30 percent by weight of polyurethane acrylate prepolymer that includes
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation at one end of the molecule, and at least one active hydrogen-containing
group at the opposite end of the molecule; and at least 10 percent by weight of
one or more prepolymers having at least one terminal polymerizable site of ethylenic
unsaturation at each end of the molecule.
The present invention is also directed to a thermosetting composition that includes:
- (I) a first reactant comprising reactive functional groups;
- (II) a curing agent having functional groups reactive with the functional
groups of the first reactant in (I);
- (III) a latex emulsion comprising crosslinked polymeric microparticles
dispersed in an aqueous continuous phase, the polymeric microparticles prepared
from a monomer mix comprised of:
- (a) at least 20 weight percent of a crosslinking monomer having
two or more groups of reactive unsaturation and/or monomers having one or more
functional groups capable of reacting to form crosslinks after polymerization;
- (b) at least 2 weight percent of one or more polymerizable ethylenically
unsaturated monomers having hydrophilic functional groups having the following
structures (I) and/or (II):
##STR1##
- wherein A is selected from H and C1-C3
alkyl; B is selected from —NR1R2, —OR3 and
—SR4, where R1 and R2 are independently
selected from H, C1-C18 alkyl, C1-C18 alkylol
and C1-C18 alkylamino, R3 and R4 are
