Note: Descriptions are shown in the official language in which they were submitted.
212~2?,~.3
Mo3966
MD-91-84-CT
RAPID CURING POLYURETHANE COMPOSITION
USEFUL AS A COATING OR SEALANT
BACKGROUND OF THE INVENTION
The present invention relates to a system, particularly a
one-component system, wh;ch cures at ambient temperature to
form a polyurethane composition useful as a coating or sealant.
Coating and sealant compositions based upon polyurethanes
and polyureas are known. Such compositions are typically
available as either one-component or two-component systems.
lo U.S. Patent 5,126,421, for example, discloses a
two-component system in which an isocyanate prepolymer is cured
with a system composed of an oxazolidine moisture scavenger and
a hydroxyl curing agent. The hydroxyl curing agent is
preferably a polyhydric polyol such as ethylene glycol,
butanediol, a polyether polyol, or a polyester polyol. The
curing system is added to the isocyanate prepolymer shortly
before it is to be applied to a substrate and allowed to cure
at ambient temperature. -
Two-component systems, such as that disclosed in U.S. -
Patent 5,126,421, avoid the storage stability problems
encountered with one-component systems. However, two-component
systems are not as easy to use as one-component systems.
One-component coating systems are disadvantageous in that
they employ aromatic polyisocyanate prepolymers. After such
systems are applied to a substrate, the skin which forms
reduces the amount of atmospheric moisture available to
complete the curing reaction and thus slows the curing process.
Taub et al reported in their paper, "Polyfunctional
Isocyanate-Oxazolidine Resins" which was presented at the
Water-Borne & Higher Solids Coatings Symposium in February 1989
that storage-stable one-component urethane coatings could be
prepared by reacting aliphatic diisocyanate prepolymers with
N-2-hydroxyethyl oxazolidines. Taub et al also reported that
aromatic isocyanate prepolymers did not produce storage stable
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one-component urethane coatings. Aliphatic isocyanate-based
systems such as those disclosed by Taub et al are, however,
disadvantageous in that they have extremely slow cure times and
"; are too expensive for most automated wood coatings production
, 5 lines.
A one-component system which is easy to use, cures within
, short per;ods of time and is storage stable would therefore be
~ particularly advantageous.
1 SUMMARY OF THE INVENTION
It is an object of the present invention to provide a
storage-stable, one-component system which cures within a short
`ZZ period of time.
It is another object of the present invention to provide a
coating material which is moisture resistant.
¦ 15 It is a further object of the present invention to provide
a process for coating a substrate in which the coating material -
dries within minutes of its application.
It also an object of the present invention to provide
coated materials~particularly coated wood materials,which are
sufficiently moisture resistant to be useful in construction ; - -~applications.
These and other objects which will be apparent to those
skilled in the art are accomplished by a system composed of a
toluene diisocyanate prepolymer having a molecular weight of
from about 1400 to about 2100 and an isocyanate group content
of from about 4 to about 6% and an oxazolidine. It is
preferred that an acid anhydride also be included in this
system.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph illustrating the results of the
stability studies done at room temperature on the formulations
of the present invention described in Examples 1-5.
Figure 2 is a graph illustrating the results of stability
studies done at 60C on the formulations of the present
invention described in Examples 1-5.
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Figure 3 is a graph illustrating the results of stability
studies done on the formulations described ;n Examples 6-10.
Figure 4 is a graph illustrating the results of the
stability studies done at room temperature on the formulations
described in Examples 11 and 12.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention relates to a one-component, fast
curing, storage-stable system which is made up of a prepolymer
of toluene diisocyanate and an oxazolidine having a molecular
lo weight of from about 1400 to about 2100 and an isocyanate group
content of from about 4 to about 6%. An acid anhydride
catalyst is also preferably included in the system. The
present invention also relates to a process for producing
coatings and sealants from this system and to substrates coated n
with this system. The systems of the present invention are
useful for coating and sealing porous substrates such as wood, ~ ~
wood composites and flake board. ~ - -
Isocyanate prepolymers are known. The toluene
diisocyanate prepolymers of the present invention may be formed
in accordance with any of the procedures known to those in the
art. These prepolymers are preferably formed by reacting
toluene diisocyanate with relatively high molecular weight
polyhydroxyl compounds, particularly polyether polyols, and a
low molecular weight glycols in amounts such that the resultant
prepolymer will have an isocyanate group content of from about
4.0 to about 6.0 at 100% solids. Isocyanate to hydro~yl group ~-
ratios of from about 1.5 to about 2.0 are generally
appropriate. The most preferred high molecular weight
polyether polyols for use in the production of the prepolymers
of the present invention are the polytetramethylene ether
glycols haYing molecular weights of from about 500 to about
1500, preferably about 1000. These polyether polyols are
commercially available under names such as Polymeg and
Terathane.
Mo3966
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The low molecular weight hydroxyl group containing
compounds included in the materials used to produce the toluene
diisocyanate prepolymers useful in the present invention
generally have a molecular weight of from about 50 to about
200. Low molecular weight diols such as ethylene glycol and
1,3-butanediol are particularly preferred. These hydroxyl
compounds are generally used in amounts of from about 1.0% to
about 5.0%, based on the weight of high molecular weight polyol
in the prepolymer forming reaction mixture. The low molecular
lo weight diols have been found to be particularly advantageous
because they reduce the amount of residual monomeric toluene
diisocyanate in the product prepolymer.
Any of the known oxazolidines may be used in the
compositions of the present invention. These oxazolidines may
contain one or more oxazolidine structures. Appropriate
oxazolid;nes are described, for example, in U.S. Patents
5,189,176 and 4,00~601. The oxzol;d;ne may also be obta;ned
from polymers or oligomers having inherent oxazolidine
functionalit;es. Suitable monocyclic oxazolidines are
represented by the formula
CH2 CIH2 '`~
0 N-R
C
Rl R2 ;.:
in which
R represents an oligomeric or polymeric chain containing at
least one carbon atom which chain may be substituted,
R1 represents hydrogen, an aliphatic or aromatic group, and
R2 represents hydrogen, an aliphatic or aromatic group.
Su;table bis-oxazolidines are represented by the formula
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C C
S ~
Io in which
R represents an oligomeric or polymeric chain,
R1 represents H, aliphatic or aromatic group, and
R2 represents H, aliphatic or aromatic group.
The monocyclic oxazolidine in which
R represents an ethoxy group,
R1 represents a methyl group, and
R2 represents a methyl group
is preferred.
The bis-oxazolidine which is a blend of the reaction
products of oxazolidinylethanol and hexamethylene diisocyanate
and oxazolidinylethanol and isophorone diisocyanate is most
preferred.
The oxazolidine is generally included in the systems of -~
the present invention in an amount of from about 1% to about
30% by weight, preferably, frnm about 11.5% to about 26.6% by
weight, based on the total weight of the system.
Curing of the systems of the present invention is promoted
by including an acid anhydride catalyst in the system. Use of
such catalyst is therefore preferred. Any of the known acid
3o anhydrides may be used. It has been found, however, that acid
anhydrides of dicarboxylic acids are particularly useful. An
example of a preferred acid anhydride suitable for use in the
systems of the present invention is methylhexahydrophthalic
Mo3966
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anhydrid~ such as that which is commercially available under
the name Lekutherm Hardener M.
The acid anhydride is generally present in the systems of
the present invention in an amount of from about 0.1% to about
1.2% by weight, preferably from about 0.01 to about 0.1% by
weight, based on the total weight of the system.
Materials which may optionally be included in the systems
of the present invention include any of the known fillers,
organic solvents, drying agents, surface-active additives,
lo anti-foaming agents, pigments, dyes, UV stabilizers,
plasticizers, bacteriostatic and fungistatic substances. Known
catalysts for the polyurethane forming reaction may also
optionally be included. It has been found, however, that the
tin catalysts which are commonly used in urethane-forming
reactions, significantly reduce the storage stability of the
one component systems of the present invention. Tin catalysts
should not therefore generally be included in the systems of
the present invention.
These optional materials preferably have a low water
content (i.e., a water content of less than 0.0~% by weightJ or -~
be treated to remove as much of the water present as is
possible prior to use in the systems of the present invention.
Fillers which are useful in the systems of the present
invention include: silicate-containing minerals such as
antigorite, serpentine, hornblends, amphibiles, chrysotile,
talc, mica, and kieselguhr; metal oxides such as kaolin,
aluminum oxides, titanium oxides, and iron oxides; metal salts
such as chalk and barium sulfate; inorganic pigments such as
cadmium sulfide and zinc sulfide; glass; asbestos powder; and
carbon fibers. The filler which is commercially available
under the name Nytal 400 is particularly preferred.
Organic solvents useful in the systems of the present
invention are those having water content of no more than 0.05%
by weight.
Mo3966
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In preparing the systems of the present invent;on, it is
preferred that the polyol, particularly where that polyol is a
polyether polyol, be treated to remove water present therein.
Such water may, for example, be removed by adding a water
scavenger to the polyether prior to use of the polyol in
preparing the toluene diisocyanate prepolymer. The
oxazolidines useful in the present invention are examples of
suitable moisture scavengers. Where an oxazolidine is added to
a polyol having a high initial water content, it may be
necessary to increase the total amount of oxazolidine used in
the production of the one-component systems of the present
invention.
It is also preferred that any additives to be used in the
system of the present invention which contain more than a trace
amount of wa$er, be treated to remove as much of that moisture
as possible prior to use in the one-component system. `~
The systems of the present invention are generally storage
stable at ambient temperature for at least 3 months.
The systems of the present invention may be used as
coatings or sealants on virtually any porous substrate. These
systems are particularly advantageous as coatings for composite
wood substrates such as lateral strand lumber products, wood
flake board products and wood flooring materials. These
coatings are typically from 3 to 30 mils thick, preferably from
2~ about 8 to about 20 mils.
The systems of the present invention may be applied to a
substrate by any of the techniques known to those in the art.
For example, by brushing it on the substrate or by roll
coating. The length of time necessary to completely cure,
will, of course, depend upon the thickness of the coating and
the temperature and amount of moisture present in the
atmosphere surrounding the coated substrate. For example, a
coated substrate which is exposed to steam would be expected to
cure at a much faster rate than a coated substrate exposed to
average atmospheric conditions.
Mo3966
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Having thus described our invention, the following
Examples are given as being illustrative thereof. All parts
and percentages given in these Examples are parts by weight and
percentages by weight, unless otherwise indicated.
EXAMPLES
In the Examples which follow, the storage stability of the
one-component system was determined by measuring the viscosity
increase in samples over time. Each material for which the
storage stability was to be determined was placed in 15
two-ounce glass jars, each of which was tightly sealed. At
pre-determined intervals, the viscosity of the contents of an
unopened jar was determined using a Haake Rotoviscometer.
Storage stability determinations were made for samples stored
at 25C+ 4C and 60C + 2C.
The following materials were used in making the systems
and coatings described in the Examples which follow:
PREPOLYMER A: Formed by reacting toluene diisocyanate which is
commercially available from Miles Inc. under the name
Mondur TDS, benzoyl chloride, the polytetramethylene
glycol which is commercially available under the name
Polymeg 1000 and 1,3-butanediol. This prepolymer had an
NCO content of 5.1% and a viscosity of 19,500 mPa.s at
25C.
PREPOLYMER B: aliphatic polyisocyanate based on isophorone
diisocyanate and dissolved in the organic solvent which is
commercially available under the name Aromatic 100.
PREPOLYMER C: an aliphatic/aromatic polyisocyanate copolymer
based on toluene diisocyanate and hexamethylene
diisocyanate and dissolved in n-butyl acetate.
OXAZOLIDINE: ~he bis-oxazolidine which is a blend of the
reaction products of oxazolidinylethanol and hexamethylene
diisocyanate and oxazolidinylethanol and isophorone
diisocyanate.
Mo3966
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SOLVENT A: Aromatic organic solvent having a flash point
above 150F which is commercially available under the name
Aromatic 150.
SOLVENT B: Aromatic organic solvent which is commercially
ava;iable under the name Aromatic 100. -
FILLER: The material which is commercially available Nytal
having a water content of no more than 0.02%.
STABILIZER: Benzoyl Chloride. -
ANHYDRIDE: The fatty acid anhydride which is commercially
lo available under the name Hardener M from Bayer AG,
Germany.
DHCD: Dicyclohexylcarbodiimide.
TIN CATALYST: The tin catalyst which is commercially available
under the designation T-12 from Air Products.
EXAMPLE 1
40 grams of PREPOLYMER A were combined with 6.87 grams of
OXAZOLIDINE. The resultant system had an initial viscosity at
room temperature of 1401 mPa.s. After storage for seven days
this system had a viscosity at room temperature of 1558 mPa.s.
After 25 days at room temperature the viscosity of the system
had increased to 1794 mPa.s. These results at room temperature
are presented graphically in Figure 1.
This system was also stored at 60~C and the viscosity
measured at this temperature over a period of 14 days. After 1
2~ day the viscosity had increased from 1401 to 1721 mPa.s. After
6 days the viscosity was measured at 2193 mPa.s. At day 14,
the system gelled. These results at 60C are presented -
graphically in Figure 2.
~XAMPLE 2
40 grams of PREPOLYMER A were combined with 6.87 grams ;~
OXAZOLIDINE and 0.05 grams of ANHYDRIDE (0.1% of the total
system). The resultant system had an initial viscosity of 1454
mPa.s at room temperature. After storage for seven days at -~
room temperature, the viscosity had increased to 1595 mPa.s.
After 25 days, the viscosity was 1903 mPa.s at room ; - -~
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temperature. These results are presented graphically in Fiyure
1.
The viscosity increase of this system after storage at
60C was also studied. The viscosity of these samples
increased from 1454 mPa.s (initial viscosity) to 1740 mPa.s (1
day) to 235~ mPa.s (6 days) to 4186 mPa.s (14 days). After 21
days~ the system gelled. These results are graphically
presented in Figure 2.
EXAMPLE 3
lo 40 grams of PREPOLYMER A were combined with 6.87 grams
OXAZOLIDINE and 0.14 grams of ANHYDRIDE (0.3% total system).
The viscosity of this system at room temperature and at 60C
was then studied.
At 25C, the viscosity increased from 1419 mPa.s (initial)
to 1613 mPa.s (7 days) to 1957 mPa.s (25 days). These results
are graphically presented in Figure 1.
After storage at 60C, the viscosity increased from 1419
mPa.s (initial) to 1758 mPa.s (1 day) to 2643 mPa.s (6 days) to
5400 mPa.s (14 days) to 11635 mPa.s (21 days). The sys~em
gelled after 42 days. These results are graphically presented
in Figure 2.
EXAMPLE 4 -~
40 grams of PREPOLYMER A were combined with 6.87 grams of -~
OXAZOLIDINE and 0.28 grams of ANHYDRIDE (0.6% of total system).
The viscosity increase of th;s system after storage at room
temperature and at 60C was studied.
At 25C, the viscosity increased from 1450 mPa.s (initial)
to 1631 mPa.s (7 days) to 2084 mPa.s (25 days). These results
are graphically presented in Figure 1.
After storage at 60~C, the viscosity of the system
increased from 1450 mPa.s (initial) to 1703 mPa.s (1 day) to
2944 mPa.s (6 days) to 8192 mPa.s (14 days) to 16583 mPa.s (21
days). The system gelled after 42 days. These results are
graphically presented in Figure 2.
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EXAMPLE 5
40.0 grams of PREPOLYMER A were combined with 6.87 grams
of OXAZOLIDINE and 0.56 grams of ANHYDRIDE ~1.2% total system).
The viscosity increase of this system after storage at room
temperature and at 60C was studied.
After storage at room temperature, the viscosity increased
from 1468 mPa.s (initial) to 1685 mPa.s (7 days) to 2820 mPa.s
(25 days). These results are graphically presented in Figure
1.
After storage at 60C, the viscosity of the system
increased from 1468 mPa.s (initial) to 1757 mPa.s (1 day) to
4530 mPa.s (6 days) to 18470 mPa.s (14 days). The system
gelled after 42 days. These results are presented graphically
in Figure 2.
EXAMPLE 6
640.1 grams of PREPOLYMER A were combined with 110 grams
of OXAZOLIDINE and 2.25 grams of DHCD. The viscosity increase
during storage at room temperature and at 60C was studied.
After storage at room temperature, the viscosity of the
system increased from 1558 mPa.s (initial) to 1631 mPa.s (3
days). The viscosity remained constant 1631 mPa.s up to day 7
when measurement was discontinued.
After storage at 60C, the viscosity of this system
increased from 1558 mPa.s (initial) to 1738 mPa.s (1 day) to
2110 mPa.s (3 days) to 2936 mPa.s (7 days). These results are
graphically presented in Figure 3.
EXAMPLE 7 -~
640.1 grams of PREPOLYMER A were combined with 110 grams
of OXAZOLIDINE, 2.25 grams DHCD, and 1.13 grams of ANHYDRIDE. ~ -
The viscosity increase of this system during storage over a
period of 7 days at room temperature and 15 days at 60C was -~
studied.
After storage at room temperature, the viscosity increased
from 1540 mPa.s (initial) to 1685 mPa.s (3 days) to 1812 mPa.s
(7 days)-
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After storage at 60C, the viscosity of the system
increased from 1540 mPa.s (initial) to 1921 mPa.s (1 day) to
2556 mPa.s (3 days) to 2972 mPa.s (7 days) to 6800 mPa.s (15
days). These results are graphically presented in Figure 3.
EXAMPLE 8
640 grams of PREPOLYMER A were combined with 110 grams of
OXAZOLIDINE, 2.25 grams DHCD, and 2.26 grams of ANHYDRIDE. The
viscosity increase of this system during storage over a period
of 7 days at room temperature and 15 days at 60C was studied.
Io After storage at room temperature, the viscosity of the
system increased from 1596 mPa.s (initial) to 1776 mPa.s ~3
days) to 1862 mPa.s (7 days).
After storage at 60C, the viscosity of the system
increased from 1596 mPa.s (initial) to 2120 mPa.s (1 day) to
2430 mPa.s (3 days) to 2972 mPa.s (7 days) tp 5900 mPa.s (15
days). These results are graphically presented in Figure 3.
EXAMPLE 9 -
640.1 grams of PREPOLYMER A were comb;ned with 110 grams
of OXAZOLIDINE, 2.25 grams DHCD and 1.13 grams of TIN CATALYST.
The viscosity increase of this system during storage over a
period of 7 days at room temperature and at 60C was studied.
After storage at room temperature, the viscosity of the
system increased from 1649 mPa.s (initial) to 1685 mPa.s (3
days). The viscosity remained at 1685 mPa.s until measurement
was discontinued after 7 days.
After storage at 60C, the viscosity of the system
increased from 1649 mPa.s (initial) to 3026 mPa.s (1 day). The
system was very nearly gelled after 3 days and had completely
gelled after 7 days. These results are graphically presented
in Figure 3.
EXAMPLE 10
640.1 grams of PREPOLYMER A were combined with 110 grams
of OXAZOLIDINE, 2.25 grams of DHCD, and 2.26 grams of TIN
CATALYST. The viscosity increase of this system during storage
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over a period of 7 days at room temperature and at 60C was
studied.
After storage at room temperature, the viscosity of the
system increased from 1669 mPa.s (initial) to 1827 mPa.s ~3
days). A decreased viscosity of 1776 mPa.s was measured after
7 days.
After storage at 60C, the viscosity of the system
increased from 1669 mPa.s (initial) to 3407 mPa.s (1 day). The
system had very nearly gelled after 3 days and was completely
gelled after 7 days. These results are graphically presented
in Figure 3.
EXAMPLE~
469.2 yrams of PREPOLYMER A, 80.6 grams of OXAZOLIDINE,
0.6 grams of ANHYDRIDE, and 77.0 grams of the rutile anatase
pigment which is commercially available from Dupont under the
designation R-960 were combined. The increase in viscosity of
this composition over a period of 60 days at room temperature --~
was studied. The increase in viscosity of the system over a
period of 35 days when stored at 60~C was also studied.
After storage at room temperature, the viscosity of the
system remained 2936 mPa.s through the first day, The
viscosity increased from 3583 mPa.s (3 days) to 3969 mPa.s (7
days) to 4225 mPa.s (28 days) to 5350 mPa.s (60 days). These
results are shown graphically in Figure 4.
After storage at 60C, the viscosity of the system
increased from 2936 mPa.s (initial) to 5057 mPa.s (1 day) to
5534 mPa.s (3 days) to 7231 mPa.s (7 days) to 20219 mPa.s (14
days) to 152,630 mPa.s (28 days). The system had very nearly
gelled after 35 days.
EXAMPLE 12
469.2 grams of PREPOLYMER A, 80.6 grams of OXA70LIDINE,
0.6 grams of ANHYDRIDE, and 77.0 grams of the rutile anatase
pigment which is commercially available from Bayer AG under the
designation R-FK-2 were combined. The increase in viscosity of
Mo3966
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-14-
the system when stored at room temperature and at 60C was
measured.
After storage at room temperature, the viscosity of the
system increased from 2954 mPa.s (initial) to 2972 mPa.s (1
day) to 3045 mPa.s (7 days~ to 3306 mPa.s (28 days). These
results are presented graphically in Figure 4.
After storage at 60C, the viscosity of the system
increased from 2954 mPa.s (initial) to 3353 mPa.s (1 day) to
4204 mPa.s (3 days) to 4929 mPa.s (7 days) to 14,24~ mPa.s ~14
days) to 23,946 mPa.s (21 days) to 49,440 mPa.s (28 days) to
90,740 mPa.s (35 days).
EXAMPLE 13
A one-component elastomeric topcoat was prepared from a
mixture of 1000 grams of PREPOLYMER A, 199.56 grams of SOLVENT
B and 360.64 grams of titanium dioxide which mixture was let
down with 199.56 grams of SOLVENT B, 24.31 grams of light
stabilizers specifically, those which are commercially
ava;lable under the names Tinuvin 292 and 1130, 6.01 grams of
the stabilizer which is commercially available under the name
Irganox 1010 in 10% xylene, 3.61 grams ANHYDRIDE and 202.14
OXAZOLIDINE. The resultant system had a solids content of
79.7% by weight. The tensile strength and elongation
(determined in accordance with ASTM D-412) were 3060 psi
(failure) and 380% (ultimate), respectively.
EXAMPLE 14
A one-component elastomeric coating composition useful for
roofing applications was made by grinding 1000 9 of PREPOLYMER
A, 211.2 grams of SOLYENT B, 240.42 grams pure titanium dioxide
[R-902], 180.32 grams decabromo diphenyl oxide (fine rehydrant
3o available from Great Lakes under the designation DE-83R and
60.11 grams antimony tr;ox;de and then lett;ng down th;s
mixture with 211.20 grams of SOLVENT B, 24.21 grams of light
stabilizers, specifically, those which are commercially
available under the names Tinuvin 292 and 1130, 6.01 grams of
the stabilizer which is commercially available under the name
Mo3966
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-15-
Irganox 1010, 3.61 grams of ANHYDRIDE and 202.11 grams of
OXAZOLIDINE. The resultant composition had a solids content of
80% by weight.
EXAMPLE 15
A one-component coating composition was prepared by -
combining 56.9 grams of PREPOLYMER A, 2~.7 grams of SOLVENT A,
8.7 grams FILLER~ 0.2 grams ANHYDRIDE and 11.5 grams of
OXAZOLIDINE.
This coating was then applied by brush to the edges of
lo panels of wood composite panel which had been preconditioned at
160F/100% for 10 minutes and placed in an oven/humidity
chamber for 5 minutes. This material effectively coated and
protected the treated edges.
EXAMPLE 16 ~ -
A one-component coating composition was prepared by ;~
combining 55.5 grams of PREPOLYMER A, 2.7 grams of PREPOLYMER
B, 8.5 grams of FILLER~ 11.2 grams of OXAZOLIDINE and 22.1
grams of SOLVENT A. -
This composition was then applied by brush to the edges of -~
panels of wood composite panel which had been preconditioned at
160~F/100% for 10 minutes at thicknesses of 30 mils and 3 mils
and placed in an oven/humidity chamber for 5 minutes to cure.
At either thickness, this coating effectively protected the
treated edges and resisted swelling.
Mo3966
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-16-
EXAMPLE 17
Three different formulations were prepared by combining
the listed materials in the amounts indicated in the following
Table 1:
TABLE 1
MATERIAL/SA~PLE A B C
PREPOLYMER A (grams) 56.9 55.4
PREPOLYMER B (grams) 2.7
PREPOLYMER C (grams) 63.4
ORGANIC SOLVENT A (grams) 22.722.1
FILLER (grams) 8.7 8.5 9.7
OXAZOLIDINE (grams) 11.5 11.2 26.6
ANHYDRIDE (grams) 0.2 0.19 0.2
Each of these formulations was applied by brush to
preconditioned panels of flake board (160F/100% for lO
minutes) in an amount to seal and fill the flake board. The
coated panels were then placed in an oven/humidity chamber for
5 minutes.
Moisture penetration and edge swell of the coated panels
were determined in accordance with ANSI (American National
Institute)/KCMA (Kitchen Cabinet Manufacturers Association)
A 161.1-1990 Test Method No. 10 for detergent and water
resistance with the exception that weight gain and swell were
determined after 48 hours rather than 24 hours.
The panels coated with Sample C had an 83% weight gain
(Edge Soak Test) and a 16% edge swell. The panels coated with
Samples A and B had weight gains of from about 5 to 7% (Edge
Soak Test) and from about 1-2% edge swell.
Mo3966
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-17-
EXAMPLE 18
Three different formulations were made with the materials
listed in Table 2 below in the amounts indicated.
TABLE 2
MATERIAL/SAMPLE A B C
PREPOLYMER A (grams) 56.9 55.48
PREPOLYMER B (grams) 2.7
PREPOLYMER C (grams) 63.4
ORGANIC SOLVENT A (grams) 22.7 22.1
FILLER (grams) 8.7 8.5 9.7
OXAZOLIDINE (grams) 11.5 11.2 26.6
ANHYDRIDE (grams) 0.2 0.19 0.2
Each of these formulations was applied by brush to -~
preconditioned panels of flake board (160Ft100% for 10
minutes) in an amount sufficient to seal and fill the flake
board. The coated panels were then placed in an oven/humidity
chamber for 5 minutes.
The degree of swelling and weight gain were determined
using the same method as was used in Example 17 for one side
overlaid oriented strandboard (Table 3) and for two side
overlaid oriented strandboard (Tables 4 and 5) treated with
formulations A and B. Panels coated with Formulation C
exhibited undesirably high swelling and weight gains.
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-18-
Table 3 Sponge Test Results of Moisture Penetration and Edge
Swell of One Side Overlaid Oriented Strandboard.
Sample A B
Property Sealed Not Seal Sealed Not Seal
Edge Swell 0.0108 0.1982 0.0093 0.1859
After 75
hours
(inches)
Percent 1.59 29.18 1.38 27.92
Edge Swell
After 75
hours
Weight 2.81 41.97 2.57 41.81
Gain After
75 hours
(grams)
Percent 1.91 17.63 1.15 18.56
Weight
Gain After
75 hours
_
0 Note: percent swell and weight gain based on original
thickness and weight of the sample.
0 .
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Table 4: Sponge Test Results of Moisture Penetration and Edge
Swell of Two Side Overlaid Oriented Strandboard.
Sample A B
Propertv Sealed Not Sealed Sealed Not Sealed
Edge Swell 0.0133 0.1092 0.0095 0.1215
After 75
hours
(inches)
Percent 1.81 14.94 1.29 16.55 -
Edge Swell
lo After 75
hours
Weight 3.16 22.89 2.32 24.54
Gain After
75 hours
(grams)
Percent 1.31 9.39 0.9631 10.09
Weight
Gain After
75 hours
: :.
Note: percent swell and weight gain based on original
thickness and weight of the sample.
Table 5: Modified ASTM Water Absorption and Thickness Swell
Test Results for Two Side Overlaid Oriented Strandboard
With Edges Sealed.
Propertv Sam~le A SamPle B
Edge Swell After 1000.0570 0.0418
hours (inches)
Percent Edge Swell of 7.80 5.59
original th;ckness
after 100 hours
Weight 6ain After 46.35 25.27
100 hours (grams)
Percent Weight Gain20.09 9.66
of the original weight
after 100 hours
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-20-
Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be
understood that such detail is solely for that purpose and that
variations can be made therein by those skilled in the art
without departing from the spirit and scope of the invention
except as it may be limited by the claims.
20.
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