Note: Descriptions are shown in the official language in which they were submitted.
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1TIZE
FLUORINATED POLYISOCYANATES
BACKGROUND OF THE INVENTION
s 1. Field of the Invention
This invention is directed to fluorinated polyisocyanates that
are useful in forming coating compositions, sealants and adhesives.
2. Description of the Prior Art
Fluorinated polyurethanes that are used as soil release agents
i o are shown in Graham US Patent 3,759,874 issued September 18, 1973.
Polyurethanes of fluorinated isocyanates that are used as adhesives are
shown in Mitsch et al US Patent 3,972,856 issued August 3, 1976.
Protective coatings of fluorinated polyurethanes of fluorinated diols or
triols
are shown in Re et al US Patent 4,782,130 issued November 1, 1988.
15 There is a need for fluorinated polyisocyanates that can be
used with acrylic polymers, polyesters, alkylds, polyols to form coatings,
adhesives, sealants and the like that can be applied with conventional
equipment and cures to tough durable compositions without baking at
elevated temperatures.
SUlVflVIARY OF THE INVENTION
A fluorinated polyisocyanate of an organic polyisocyanate
reacted with a fluorinated monofunctional alcohol represented by the
formula
R3
I
Rf-(X)ri (CHZCH-O)m H
where Rf is a fluoroalkyl containing group having at least 4 carbon atoms,
X is a divalent radical, R3 is H or an alkyl group having 1-4 carbon atoms,
n is 0-l and m is 0-30 provided that when n is 0 then m must be equal to or
greater than 1 and when m is 0 then n is 1; wherein about 0.1-33 mole
so percent of active isocyanate groups are reacted with the fluorinated
monofunctional alcohol.
Compositions containing the fluorinated polyisocyanate and
articles coated with such composition also are part of this invention.
DETAILED DESCRIPTION OF THE INVENTION
The fluorinated organic polyisocyanate is an adduct of a
fluorinated monofunctional alcohol and a conventional organic
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polyisocyanate. Any of the conventional aromatic, aliphatic, cycloaliphatic
di and trifunctional polyisocyanates can be used. Typically useful
diisocyanates are 1,6-hexamethylene diisocyanate, isophorone diisocyanate,
4,4'-biphenylene daisocyanate, toluene diisocyanate, bis cyclohexyl
diisocyanate, tetramethylene xylene diisocyanate, ethyl ethylene
diisocyanate, 2,3-dimethyl ethylene diisocyanate, 1-methyltrimethylene
diisocyanate, 1,3-cyclopentylene diisocyanate, 1,4-cyclohexylene
diisocyanate, 1,3-phenylene diisocyanate, 1,5-naphthalene diisocyanate,
bis-(4-isocyanatocyclohexyl)-methane, 4,4'-diisocyanatodiphenyl ether and
i o the like.
Typical trifunctional isocyanates that can be used are
triphenylmethane triisocyanate, 1,3,5-benzene triisocyanate, 2,4,5-toluene
triisocyanate and the like. Oligomers of diisocyanates also can be used
such as the trimer of hexamethylene diisocyanate which is sold under the
tradename "Desmodur" N. One particularly preferred oligomer is
"Desmodur" N-3390.
Typical fluorinated monofunctionat alcohols used to form the
isocyanate functional adducts are represented by the formula
R3
i
Rf-(X)ri (CH2CH-O)m H
z o where R f is as defined above, a fluoroalkyl containing group
having at least 4 carbon atoms and preferably a straight chain or branched
chain fluoroalkyl group having 4-20 carbon atoms which optionally can
contain oxygen atoms as ether groups or can contain 1-5 chlorine atoms or
1-5 hydrogen atoms. Preferably, R f is a perfluoroalkyl group having 4-20
as carbon atoms and most preferably, Rfis a perfluoroalkyl group containing
6-12 carbon atoms. X is a divalent radical, preferably -CH2CH20-,
-S02N(R4)CH2CH20-, -CH2-, -O-, -CH20- where R4 is an alkyl group
preferably having 1-4 carbon atoms. R3 is H or an alkyl group having 1-4
carbon atoms, H and methyl being preferred, n is 0-1 and m is 0-30,
3 o provided that if n is 0, then m must be greater than or equal to 1, if m
is 0,
then n is 1, if X is -O-, m must be greater than or equal to 1; m preferably
is
1-20.
The following are preferred fluorinated monofianctional
alcohols:
Rf-( CHZ-CH2 O~H
2
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where R f is a perfluoroalkyl group having 6-12 carbon atoms
and n is S-15;
H-(~CF2CF2)n-CH20H
where n is 1-6;
Rs
i
C8F~~-S02 N-(CH2-CH2-C~H
where RS is an alkyl group having 1-4 carbon atoms and n is
1-30;
CF3
CF3-EO-C-CF2 nO-(-CHZ-CHZ O mH
F
where n is 0-10 and m is 1-20; and
to
R~-CH2---CH2--OH where R f is described above.
The fluorinated organic polyisocyanate is prepared by
conventional techniques in which the fluorinated nonfunctional alcohol and
ss organic polyisocyanate are charged into a reaction vessel optionally with
solvents and a catalyst for about 0.1-4 hours and heated to about 50-
120°C
preferably, 60-85°C.
About 0.1-33 mole percent of active isocyanate groups of the
organic polyisocyanate are reacted with the fluorinated monofunctional
a o alcohol which leaves sufficient amount of unreacted isocyanate groups to
react with functional groups of other components of a composition to form
a crosslinked composition on curing. Preferably, about 0.1-10 mole percent
of active isocyanate groups are reacted with the fluorinated monofunctional
alcohol to provide a less costly fluorinated organic polyisocyanate which
25 call be used with other film forming polymeric components having groups
that are reactive with isocyanates to form crosslinked compositions.
Typical solvents that are used are alkyl acetates such as ethyl
acetate, butyl acetate and the like, alkylene glycol alkyl ether acetates such
as ethylene glycol, mono butyl ether acetate and the like.
s o Typical catalysts that are used are organo tin containing
catalysts like alkyl tin laurates such as di-n-butyl tin dilaurate, dibutyl
tin
di-2-ethylhexoate, stannous octoate, stannous oleate and the like.
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The fluorinated polyisocyanate when blended with another
film forming binder is useful for forming coating compositions, adhesives,
sealants, caulks and the like. Typical film forming binders are polymeric
components having groups such as hydroxyl, carboxyl, epoxy amine, amide
and the like that are reactive with an isocyanate such as acrylic polymers,
polyesters, alkyd resins, polyetlaers, hydroxy or carboxyl containing
polyurethanes and the like.
The fluorinated polyisocyanates are particularly useful in
forming high quality coating compositions. These coating compositions can
s o be clear coat compositions used over a pigmented base coat containing
solid
color pigments or metallic flake pigments or mixtures thereof and can be
used as a conventional pigmented composition. The coating composition
can be applied with conventional spray equipment and cured at ambient
temperatures or slightly elevated temperatures which decrease drying time.
i5 The resulting finish whether clear or pigmented has excellent dirt, water
and
oil repellence, is easily cleaned by washing with water or a water surfactant
mixture or can readily be wiped clean and has good stain resistance and
good weatherability.
One useful coating composition is a clear coating
~o composition, i.e. containing no pigments or a small amount of transparent
pigment. The composition has a relatively high solids content of about 45-
80% by weight of binder and about 20-55% by weight of an organic Garner
which can be a solvent for the binder or a mixture of solvents and non
solvent which would form a non aqueous dispersion. The composition has
z5 a low VOC (volatile organic content) and meets current pollution
regulations.
Typically useful acrylic polymers that can be used to form the
aforementioned coating compositions are formed by conventional
polymerization procedures using conventional solvents and catalysts.
so Typical polymerizable monomers that are used to form these acrylic
polymers are alkyl (meth)acrylates, meaning alkyl acrylates and alkyl
methacrylates, having 1-18 carbon atoms in the alkyl group such as methyl
methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl
methacrylate, isopropyl methacrylate, butyl acrylate, isobutyl methacrylate,
35 butyl methacrylate, t-butyl methacrylate, pentyl acrylate, pentyl
methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl
methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl
methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl
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methacrylate; other useful monomers are styrene, alpha methyl styrene,
acrylamide, methacrylamide, acrylonitrile, hydroxy methacrylamide and the
like or any mixtures of these monomers, and hydroxy alkyl (meth)acrylates
meaning hydroxy alkyl acrylates and hydroxy allcyl methacrylates having 1-
4 carbon atoms in the alkyl groups such as hydroxy methyl acrylate,
hydroxy methyl methacrylate, hydroxy ethyl acrylate, hydroxy ethyl
methacrylate, hydroxy propyl methacrylate, hydroxy propyl acrylate,
hydroxy butyl acrylate, hydroxy butyl methacrylate and the like.
To improve weatherability of the coating composition,
1 o ultraviolet light stabilizers, screeners, quenchers and antioxidants can
be
added. Generally, the coating composition contains a catalyst such as an
alkyl tin laurate to cure at ambient temperatures and often contains a flow
control agent.
Coating compositions formulated with the fluorinated
i5 polyisocyanate can be used as a clear coating on a vehicle such as a car,
truck, bus, train, or on construction equipment, industrial equipment,
structures such as tanks, bridges, exterior or interior of buildings, a
basecoating which may be either a solvent based or waterbased composition
is first applied and then the clear coating is applied usually by conventional
a o means such as spraying or electrostatic spraying. The clear coating is
dried
and cures at ambient temperatures but moderately high temperatures of up
to about 90°C can be used to shorten drying time.
V~hen the fluorinated polyisocyanate is used as a crosslinking
agent in a clear coat that is used over a pigmented base coat, it is highly
25 desirable to use at least some fluorinated polyisocyanate in the base coat
to
significantly reduce cratering in the base coat. Usually, about 10-40% by
weight, based on the weight of the binder, of the fluorinated polyisocyanate
is used in the base coat.
The following examples illustrate the invention. All parts and
s o percentages are on a weight basis unless otherwise specified. Molecular
weight was determined by gel permeation chromatography using
polystyrene as the standard.
EXAMPLE 1
35 Fluorinated polyisocyanate solution I was prepared by mixing
the following constituents in a reaction vessel equipped with a mechanical
stirrer, condenser, nitrogen inlet and a thermocouple:
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Portion 1 Parts by Weight
Aliphatic isocyanate resin - trimer of hexamethylene 3000.00
diisocyanate (98.9% solids)
Butyl acetate 275.00
Ethyl acetate 550.00
Ethylene glycol monobutyl ether acetate 175.00
Portion 2
Fluoroalkyl alcohol 27.20
F(CF2~CH2CH20(CH2CH20)mH where n is an
average of 6 and m is an average of 7.5
Di-n-butyl tin dilaurate solution (2% solids in ethyl 0.50
acetate)
Total 4027.70
Portions 1 and 2 were each added to the reaction vessel under
a positive pressure of nitrogen and heated to about 75-80°C and held at
this
temperature for about 2 hours and allowed to cool overnight. The resulting
fluorinated polyisocyanate solution I contained about 1% of the fluorinated
s component.
Fluorinated polyisocyanate solution II was prepared as above
except the amount of the fluorinating component was reduced by 50%
which resulted in a fluorinated polyisocyanate that contained 0.5% of the
fluorinated component.
to An acrylic polymer I solution was prepared in which the
acrylic polymer has fluoro alkyl groups by charging the following
constituents into a reactor equipped with a heat source, a thermometer and a
stirrer:
Portion 1 ~ Parts By Wei,.~ht
Methyl amyl ketone 699.20
Portion 2
Butyl methacrylate monomer (BMA) 583.80
Styrene monomer (S) 307.28
Butyl acrylate monomer (BA) 343.20
Hydroxy propyl acrylate monomer (II~PA) 783.60
Methyl amyl ketone 4.72
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Portion 3
Fluoroalkyl ethyl methacrylate monomer (FAMA) - 30.73
(fluoroalkyl group containing C-4 about 4%, C-6 about
30%, C-8 about 30%, C-10 about 20%, C-12 about
10% C-14 and above about 5%)
Methyl amyl ketone 30.00
Portion 4
T-butyl peroxy acetate 69.01
Methyl amyl ketone 114.59
Portion 5
Methyl amyl ketone 33.28
Total 2999.99
Portion 1 was charged into the reaction vessel and blanketed
with nitrogen and Portion 2 was premixed and added over a 360 minute
period while holding the resulting mixture at its reflex temperature of about
150°C. Portion 3 was premixed and then added at one time to the
reaction
mixture 350 minutes after the start of the addition of Portion 2. Portion 4
was premixed and added at the same time as Portion 2 to the reaction
mixture over a 375 minute period and then Portion 5 was added and the
reaction mixture was held at its reflex temperature for an additional 60
minutes. The resulting polymer solution was cooled to room temperature.
to The resulting acrylic polymer solution I had a weight solids
content of about 70%, a polymer of BMA/SBA/HPA/FAMA in the
following percentages 28.5%/15.0%/16.75%/38.25%/1.5% and the polymer
had a weight average molecular weight of about 7,000.
A clear acrylic composition I was prepared as follows:
Parts by Wei _ t
Portion 1
Methyl ethyl ketone 2.54
Toluene 2.67
Dibasic acid ester (ester mixture of adipic 1.79
acid, glutaric
acid and succinic acid)
Butyl Cellosolve Acetate 4.96
Portion 2
Acrylic polymer I solution (prepared above) 72.79
Portion 3
Resiflow S (Acrylic polymer flow additive) 0.35
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"Tinuvin" 328 - 2-(2-hydroxy-3,5-ditertiary amyl phenol) 5.58
-2H-benzotriazole)
"Tinuvin" 292 - (1,2,2,6,6-pentamethyl-4-piperidinyl) 0.87
sebacate
Dibutyl tin dilaurate 0.92
PM acetate 7.38
Total 100.00
The constituents of Portion 1 were charged into a mixing
vessel in the order shown with continuous mixing. Portion 2 was added and
mixed for 15 minutes. The constituents of Portion 3 were charged into the
mixing vessel in the order shown with constant mixing. The resulting
s composition had a solids content of about 53.5%.
A clear coating composition I was prepared by mixing the
above clear acrylic composition I with a the above prepared fluorinated
polyisocyanate solution I in a 3/1 volume ratio. Clear coating composition
II was prepared by mixing the above clear acrylic composition I with the
to above prepared fluorinated polyisocyanate solution II in a 3/1 volume
ratio.
Two phosphated cold rolled steel panels that had been coated
with a cured electrocoating composition of a polyepoxy hydroxy ether resin
crosslinked with a polyisocyanate were spray coated with a white basecoat
coating composition of an acrylic polymer containing an organic
15 polyisocyanate crosslinking agent to a dry film thickness of about 18-23
microns. The basecoat was allowed to stand for about 10 minutes to allow
solvent to evaporate and then the above prepared clear coating composition
I was spray applied. Two coats were applied with a solvent evaporation
time of 2 minutes between the application of each coat. The resulting film
2o was dried at about 83°C for about 30 minutes. The dry flm_ thickness
of
the clear coat was about 44-56 microns. The resulting clear coat was
smooth and essentially free of craters and had an excellent appearance.
A second set of two panels was prepared. Phosphated cold
rolled steel panel electrocoated with the same above described
z s electrocoating composition were coated with a black basecoat coating
composition identical to the white basecoat coating composition except
black pigmentation was used instead of white pigment and coated with the
clear coating composition I as above and dried and cured as above. The
resulting clear coat was smooth and essentially free of craters and had an
s o excellent appearance. The following properties of the clear coated panel
8
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were measured and the results are shown in Table I: 20° Gloss and
Distinctness of Image (DOI).
Acrylic polymer II solution was prepared which is identical to
the above acrylic polymer I solution except that fluoroalkyl ethyl
s methacrylate monomer was not added. The molecular weight of the
polymer and the solids of the solution were about the same. A clear coating
composition III was prepared as above using fluorinated polyisocyanate
solution I (prepared above) and acrylic polymer II solution was used in
place of acrylic polymer I solution. Two panels of phosphatized cold rolled
s o steel coated with the same electrocoating composition and with the same
white base coat were sprayed with the clear acrylic coating composition III
and cured as above. Also, two panels of phosphatized cold rolled steel
coated with the same electrocoating composition and with the same black
base coat were sprayed with the clear coating composition III and cured as
is above. The same properties were measured for both sets of panels as above
and the results are shown in Table 1.
A clear coating composition IV was prepared as above using
fluorinated polyisocyanate solution II (prepared above) and acrylic polymer
II solution was used in place of acrylic polymer I solution. Two panels of
a o phosphatized cold rolled steel coated with the same electrocoating
composition and with the same white base coat were sprayed with the clear
coating composition IV and cured as above. Also, two panels of
phosphatized cold rolled steel coated with the same electrocoating
composition and with the same black base coat were sprayed with the clear
as coating composition IV and cured as above. The same properties were
measured for both sets of panels as above and the results are shown in
Table 1.
TABLE 1
Calculated
Clear Base 20 DOI PPM
Coat Coat oss Fluorine in
Com osition
I black 80.2 81.3 6500
I black 86.6 89.2 6500
I white 77.2 60.2 6500
I white 83.2 67.4 6500
II black 77.5 90. 5600
7
II black 85.3 _ ~ 5600
91.3
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II white 85.8 96.8 5600
II white 86.1 89.2 5600
III black 80.1 95.6 1700
III black 81.7 95.7 1700
III white 78.2 94.5 1700
c
III white 76.9 90.0 1700
IV black 76.5 97.1 900
IV black 78.7 86.6 900
IV white 80.0 96.3 900
IIV white 79.6 96.6 900
~ 1
Each of the Clear Coats I-IV has excellent gloss and
distinctness of image (DOI)
s EXAMPLE 2
Fluorinated polyisocyanate solution III was prepared by
mixing the following constituents in a reaction vessel equipped with a
mechanical stirrer, condenser, nitrogen inlet and a thermocouple:
Portion 1 Parts By Wei . t
Aliphatic isocyanate resin (described in Example 1) 3,626.0
Butyl acetate 332.0
Ethyl acetate 665.0
Ethylene glycol monobutyl ether acetate 212.0
Portion 2
Fluoroalkyl alcohol 116.0
[F(CF2CF2}nCH2CH20H which is a blend of
homologuous series where 1-2% n =2, 27-34% n = 3,
29-34% n = 4, I7-21% n = 5, 6-9% n = 6, 2-5% n = 7
and 1-2% n = 8]
Di-n-butyl tin dilaurate (2% solids in ethyl acetate) 0.5
Total 4951.5
Portions 1 and 2 were each added to the reaction vessel under
zo a positive pressure of nitrogen and heated to about 75-85°C and held
at this
temperature for about 2 hours and allowed to cool overnight. The resulting
fluorinated polyisocyanate solution III contained about 2.5% of the
fluorinated component.
A clear coating composition V was prepared by mixing the
15 clear acrylic composition I, described in Example 1, with the above
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fluorinated polyisocyanate solution III in a 3/1 volume ratio. Two
phosphated cold rolled steel panels electrocoated as described in Example 1
were spray coated with a white base coat described in Example 1 and
coated with the clear coating composition V and cured following the
procedure of Example 1. The resulting clear coat was smooth and
essentially free of craters and had an excellent appearance and had excellent
soil resistance and was easily washed or wiped clean.
EXAMPLE 3
1 o Fluorinated polyisocyanate solution IV was prepared by
mixing the following constituents in a reaction vessel equipped with a
mechanical stirrer, condenser, nitrogen inlet and a thermocouple:
Portion 1 Parts By Wei t
Aliphatic isocyanate resin (described in Example 1) 3,064.0
Butyl acetate 281.0
Ethyl acetate 562.0
Ethylene glycol monobutyl ether acetate 179.0
Portion 2
Fluoroallcyl alcohol 27.8
[Rf CH2CH2-O-(CH2CH20~-H where Rf is
approximately 1% CF9, 50-60% C6F13, 20-40%
C8F17, 5-15% C10F21, 1-5% C12F25, n is 15-20]
Di-n-butyl tin dilaurate (2% solids in ethyl acetate) 0.5
Total 4114.3
Portions 1 and 2 were each added to the reaction vessel under
a positive pressure of nitrogen and heated to about 75-85°C and held at
this
temperature for about 2 hours and allowed to cool overnight.
A clear coating composition VI was prepared by mixing the
clear acrylic composition I, described in Example 1, with the above
fluorinated polyisocyanate solution IV in a 3/1 volume ratio. Two
phosphated cold rolled steel panels electrocoated as described in Example 1
2 o were spray coated with a white base coat described in Example 1 and
coated with the clear coating composition VI and cured following the
_ procedure of Example 1. The resulting clear coat was smooth and
essentially free of craters and had an excellent appearance and had excellent
soil resistance and was easily washed or wiped clean.
J
11
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