Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02381872 2002-04-17
FOAMABLE COMPOSI'CION EXHIBITING INSTANT THIXOTROPIC
GELLING
Cross Reference to the Related Application
This application is a continuation-in-part of Application No. 09/148,434,
filed
September 4, 1998, now pending, which claims the benefit of U.S. Provisional
Application No. 60/058981, filed September 10, 1997.
Field of the Invention
The invention relates to a foamable composition comprising at least two parts.
More specifically, the first part comprises at least one polyol, at least one
thixotropic
gelling agent, and at least one blowing agent wherein the first part comprises
an effective
amount of hydrophobic ingredients and a second part comprising at least one
isocyanate.
A foam mass can be prepared by a method of combining the polyol component with
the
isocyanate component substantially free of urethane prepolymer and applying
the mixture
to a void or substrate. The invention also relates to methods of using the
foamable
composition in the repair of surface defects or for the reinforcement of
structural
members such as spike holes left: after spike removal from railroad ties
during road bed
maintenance or repair. The invention further relates to a method of foaming
the
composition in the presence of water.
Background of the Invention
:~5 Materials used to repair defects in structural members should have certain
characteristics. The material should be easily applied and should form high
strength
bonds to structural members made of varying materials. Particularly for
outdoor repairs,
the repair materials should be usable in many environments including
environments
having extremes of heat and cold and having the presence of substantial
quantities of
:30 environmental water.
One particularly important end use for such repair compositions is in the
recycle
or reuse of railroad ties. Typically in the maintenance of the railroad right
of way, the
rails along with the tie plates and spikes, are removed from railroad ties
which remain in
CA 02381872 2002-04-17
the roadbed. If a new rail is to be spiked to the old tie, it is critical that
the railroad tie
spike holes be repaired prior to laying the new rail. The presence of spike
holes in an old
tie can cause problems since if a spike is driven into a portion of the tie
near an old spike
hole, the driving force of the spike can displace the spike from its intended
location into
an old hole, displacing the rail, tie plate and spike. In the instance that
the spike is driven
into an incorrect location substantial economic loss can result in repairing
the misaligned
rail. If a misaligned rail is not repaired, the defect can cause derailment or
other
problems. Further, the spike holes can be the source of structural weakness in
the tie,
allowing water to enter the core of the tie accelerating the degradation.
Mechanical spike hole repair means have been suggested in the art. For
example,
Moses, U.S. Pat. No. 3,191,864, issued June 29, 1965 teaches a mechanical
spike hole
insert used by first boring out an old spike hole, installing an insert and
driving a new
spike into the insert. Newman U.S. Pat. No. 3,716,608, issued Feb. 13, 1973
teaches
metallic inserts that can be placed in bored out spike holes with a filling of
a synthetic
resin into which the spikes can be driven. In another area of repair,
Tessenski, U.S. Pat.
Nos. 4,070,201 and 4,152,185, issued Jan. 24, 1978 and May 1, 1979
respectively, teach
a railroad tie spike hole plugging material and method using a substantial
uniform
mixture of a granular abrasive material and a granular plastic material which
is poured
into the hole left after spike removal. The driving force of a spike into the
abrasive
material generates heat which plasticizes the material resulting in a firm
bond of the
spike to the material. Mechanical and resin-based hole filling methods tend to
be time
consuming, expensive and adapted to manual, not automatic application or
installation.
Rhodes et al., U.S. Pat. No. 4,295,259, issued Oct. 20, 1981, teaches a method
of
reusing wooden railroad ties in which the old spike holes are filled with a
high-density
rigid polyurethane foam injected into the holes. At col. 4, lines 14-20, this
reference
states that "Manufacturers of polyurethane chemicals caution that both
components not
be allowed to drop below 55°F ( 13°C) at any time, including
shipping and storage.
Temperatures below 55°F (13 "C) apparently have a deleterious effect on
the properties
of the final product. Temperature control during operation is used to regulate
viscosity."
Other polyurethane foam compositions have been suggested for other uses. For
example, Maruyama et al., U.S. Pat. No. 4,264,743, issued April 29, 1981,
teaches a
polyurethane foam sealing material prepared from a polyisocyanate and a polyol
2
CA 02381872 2002-04-17
component, a major portion of'said polyol component consisting of polyol
derived from a
dimer acid or castor oil, or a mixture thereof in the presence of a blowing
agent, a foam
stabilizer, a catalyst, and optionally, a lipophilic filler. As the catalyst,
tertiary amines
and organotin compounds are preferably used. The sealing materials are
suitable for use
in fender, ventilator, air conditioning joints and other parts in automobiles,
as well as in
ships, refrigerators and other assembly products.
Barker et al., U.S. Pat. No. 5,124,367, issued June 23, 1992 teaches a fire
retardant composition comprising a dispersion of solid fire retardant additive
in a liquid
isocyanate-reactive compound having a functionality of from 2 to 8 and an
average
equivalent weight of from about 31 to about 5000 and, as an anti-settling
agent, an
effective amount of a fatty acid ester and/'or amide such as castor oil. The
anti-settling
agent is disclosed in an amount of 0.05 to 5%. The composition is useful in
the
manufacture of fire resistant flexible and rigid foams.
Grimm et al., U.S. Pat. No. 5,470,515, issued Nov. 28, 1995, teaches
insulating
pipes by application of at least one insulating layer and at least one outer
surface layer by
rotational molding. A rigid polyurethane foam is used as the insulating layer
while a
solid polyurethane is used as the surface layer. The rigid polyurethane foam
is obtained
by the reaction of a) an aromatic isocyanate with b) a polyol component
bearing on
average at least 3 isocyanate-reactive hydrogen atoms containing 1. a
polyether
containing at least two hydroxyl groups and having a molecular weight of 300
to 700, 2.
an aliphatic, cycloaliphatic or aromatic polyamine having a molecular weight
of 32 to
1,000 as a crosslinking agent and a blowing agent, and optional ingredients.
The solid
polyurethane is obtained by the reaction of a) an NCO-terminated prepolymer
having an
NCO content of 5 to 20% obtained by the reaction of 1 ) 4,4'-diphenyl methane
. diisocyanate, optionally admixed with 2,4' and 2,2'-isomers and 0 to 30% by
weight .
components of high functionality with; 2) polyethers containing 2 to 4 OH
groups having
a molecular weight of 1,000 to 6,000 to which up to 30% by weight of a
hydrophobicizing agent, preferably castor oil, has optionally been added with
b) a polyol
component containing 1 ) a polye;ther containing 2 to 4 isocyanate-reactive
hydrogen
:30 atoms and having a molecular weight of 1,000 to 6,000; 2) 5 to 35% by
weight of an
aromatic diamine having a molecular weight of 122 to 400; 3) 0 to 5% by weight
of an
CA 02381872 2002-04-17
aliphatic or cycloaliphatic diamine having a molecular weight of 60 to 4000;
4) 0 to 30%
of a hydrophobicizing agent and 5) optionally auxiliaries and additives.
Doyle et al., U.S. Pat. No. 4,248,811, issued Feb. 3, 1981, teaches equipment
and
formulations for the filling of ordinary pneumatic tires with a polyurethane
foam.
Exemplified is a composition wherein component A contains 4,4'-diphenylmethane
diisocyanate (MDI) 5 equivalents 665 lbs. and hydroxy-terminated polybutadiene
1
equivalent 1250 lbs. and component B contains hydroxy-terminated polybutadiene
1.1
equivalents 1375 lbs., castor oil 1 equivalent 340 Ibs, 1,4-butanediol 1
equivalents 80.1
lbs, silicone surfactant 35 lbs, tertiary amine catalyst 4.5 lbs., lead
octoate catalyst 4.5
lbs, and tall oil fatty acid 30.0 lbs. The castor oil is added to
compatibilize the
polybutadiene.
The use of polyurethane foam in filling spike holes in used railroad ties can
present significant problems. 'The polyurethane foam compositions do not
appear to
adhere to a spike hole with sufficient adhesion to prevent the accidental
removal of the
foam repair mass during the repair and subsequent mechanical rail
installation. Further,
the urethane foams of the prior art tended to foam uncontrollably in the
presence of
substantial environment moisture. Since moisture tends to accelerate the
foaming
properties of the urethane composition, the presence of water can cause too
rapid of cell
expansion resulting in a foam mass of low strength and low density which can
result in
:Z0 the formation of an incomplete or unreliable repair of structural members.
Morin, U.S. Pat. No. 4,661,532, issued April 18, 1987, teaches coal tar
containing
foaming urethane compositions and a method of repairing defects in structural
components. A two package hydrophobic urethane foaming composition is
disclosed in
which the first package comprises a polyol made hydrophobic by the presence of
an
:?5 effective amount of a coal tar or coal tar pitch composition. Although the
use of coal tar
significantly improved the problems associated with adhesion and uncontrolled
foaming
of the polyurethane composition in the presence of substantial moisture, this
approach
has had limited commercial success due to worker safety hazards since coal tar
has been
identified as a carcinogen. Hence, products were developed in which the coal
tar was
:30 replaced with a mixture of hydrophobic polyols comprising about 20 wt-%
castor oil
present in the polyol component. The viscosity of each part of such products
is about
2,000 cPs at 77°F (25 °C), but increases to about 50,000 cPs at
50°F ( 10 °C), and in the
4
CA 02381872 2002-04-17
excess of 100,000 cPs at 40°F (4 °C). Hence, the coal tar
containing compositions as
well as the non-carcinogenic modifications were found to be difficult to apply
by
conventional application equipment without the addition of heat. The
recommended
application temperature for such products ranged from about I 30°F (54
°C) to about
I40°F (60 °C). As railroad repair becomes a year-round task,
rather than seasonal during
warmer months of the year, the difficulty in application became quite
problematic.
Accordingly, a substantial need exists in the art for foamable compositions
employing non-carcinogenic ingredients that can be used to repair surface
defects on
structural components such as railroad ties to provide a repair mass having
strong
adhesion to the substrate structural member, which can be used in the presence
of
substantial quantities of environmental water and can be used in automatic
application
equipment in all temperatures.
Summary of the Invention
l 5 The invention features a foamable composition that can be foamed in the
presence of high concentrations of water. The foamable composition builds
viscosity and
forms a thixotropic gel sufficieni:ly fast enough that it can be foamed in the
presence of
environmental water, or even underwater, while still maintaining excellent
foam quality
such as consistent foam structure, high strength and high foam density. The
foamable
;?0 composition exhibits excellent adhesion to a variety of substrates
including plastic, metal
and wood, even when such substrates are wet or under water.
In one aspect, the present invention is a foamable composition having at least
two
parts comprising:
a) a part A comprising at least one polyol, at least one gelling agent, and at
25 . least one blowing agent; wherein the part A comprises an effective
amount of hydrophobic ingredients; and
b) a part B comprising at least one isocyanate.
Preferably, the polyol is castor oil and the gelling agent is a polyamine.
Further,
the polyurethane composition preferably further comprises at least one
plasticizer in part
30 A and/or part B to reduce the viscosity as well as certain catalysts to
attain the proper
reaction rates after mixing and application. Advantageously, each part
exhibits a low
5
CA 02381872 2002-04-17
viscosity over a wide temperature range, having a Brookfield viscosity of less
than about
10,000 cPs at temperature ranging from about 20°F (-7 °C) to
40°F (4 °C).
In another aspect, the invention further relates to a foam mass prepared by a
method of:
a) forming a mixture comprising a polyol component comprising at least one
polyol, at least one gelling agent, and at least one blowing agent and an
isocyanate component substantially free of prepolymer;
b) applying the mixture to a void or substrate.
In this embodiment, the isocyanate component is preferably substantially free
of
l 0 isocyanate reactants to avoid the formation of a prepolymer which tends to
substantially
increase the viscosity of the isocyanate component.
In a preferred embodiment the present invention further relates to a foamable
composition comprising:
a) a part A comprising an amount of 30 wt% or greater of at least one
l5 hydrophobic polyol, at least one gelling agent, and at least one blowing
agent; and
b) a part B comprising at least one isocyanate.
Another aspect of the present invention is to provide a polyurethane foam
composition that is substantially unaffected by variations in the
concentration of blowing
20 agent such as water. It is surmised that the hydrophobic agent and moisture
form an
equilibrium at the exterior surface of the foam limiting the further take-up
of moisture.
In yet another aspect, the invention features a foamable composition
comprising
at least two parts:
a) a first part comprising at least one polyol; at least one thixotropic
gelling
:?5 . agent; at least one blowing agent; at least one urethane reaction
catalyst;
and at least one isocyanurate reaction catalyst, and
b) a second part comprising at least one isocyanate.
The composition can be formulated such that the polyol, preferably, does not
contain any
ester linkage, such as the ester linkage in castor oil or its derivatives. The
composition
30 can also be formulated such that there is no hydrophobic ingredient
included. Further, the
composition can be formulated to exhibit, upon machine mixing the first part
and the
second part, instant thixotropic gelling so that it is controllably foamable
in the presence
6
CA 02381872 2002-04-17
of a large amount of environmental water, and even under water. The
composition can
also be formulated to exhibit, upon foaming under water, very high wet foam
density that
is substantially the same as dry foam density
In yet another aspect, the invention relates to a method oPrepair or
reinforcement
of a structural member comprising the steps o~
a) providing a structural member having a void;
b) providing a foamable composition comprising a mixture of
t) a first part comprising at least one polyol, at least one gelling
agent, and at least one blowing agent; wherein the first part
comprises an effective amount of hydrophobic ingredients and
ii) a second part comprising at least one isocyanate;
c) applying the mixture to the void.
The composition initially has a relatively low viscosity upon mixing. However,
the applicant surmises that the thixotropic nature of the polyamine causes the
composition to attain the proper consistency for good repair or reinforcement
almost
immediately upon application. Since the consistency of the foam relies on a
chemical
reaction, the thixotropic nature of the composition, rather than merely the
initial viscosity
of the blended parts, the composition may be easily applied at temperatures
ranging from
about -20°F (-29 °C) to about I ~0°F (49 °C).
In yet another aspect, the invention further relates to a method of foaming a
polyurethane composition underwater comprising the steps of
a) providing a substrate submerged in an aqueous environment;
b) providing a polyurethane composition in an applicator having an exit port,
said composition comprising:
. t) a first part: comprising at least one.polyol, at least one gelling
agent, and at least one blowing agent; wherein the first part
comprises an effective amount of hydrophobic ingredients, and
ii) a second part comprising at least one isocyanate;
c) blending the first and second part to form a mixture;
d) submerging the exit port in said aqueous environment;
e) applying the mixture to said substrate.
7
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Description of the Drawings
Figure 1, titled "Ball Mill Demolition Test" depicts the resistance to erosion
and
impact and abrasion of Example 5 foamed at a density of about 18 -22 lb/ft3
(0.29 - 0.35
kg/dm3) an embodiment in accordance with the present invention and Comparative
Example A. The foamable compositions of the present invention exhibit a
percent loss
20% lower than Comparative A over the course of time tested representative of
a 50%
improvement in percent loss at ~)6 hours and about a 30% improvement at 288
hours.
Figure 2 depicts the storage modulus (G' ), loss modulus (G"), and tan delta
of
Example 5 foamed at a density of about 18 -22 lb/ft3 (0.29 - 0.35 kg/dm3). The
G' is
related to the strength of the foam. The foamable compositions of the present
invention
are rigid, having a G' greater than 1 X 106 dynes/cm2 over a temperature
ranging from
20°C to 100°C.
Detailed Description of the Invention
The term polyurethane fi~am as described herein is defined as a polymer
containing at least two urethane groups including ureas, isocyanurates and
biurets. More
specifically, the foam of the present invention is a polyurethane-urea-
isocyanurate foam.
In other words, the foam formed from the foamable composition of the invention
is
considered as an isocyanurate-modified polyurethane foam. "Hydrophobic" refers
to
those ingredients having a concentration of water at ambient temperature of
less than 1%
after being conditioned for 14 days at 100°F (38 "C) and 95% relative
humidity in a
cylindrical container about 4 cm in height having an inside diameter of about
3 cm.
The foamable composition of the present invention comprises at least two
parts.
Upon mixing the two parts and exposing the mixture to environmental pressures
and
temperatures, the. composition foams. Generally, each part is provided
separately and
mixed immediately prior to application. However, the invention also
contemplates
encapsulated ingredients, particularly encapsulated catalysts and/or
isocyanates and/or
gelling agents. In these embodiments, the composition may be provided as a
single
mixture.
The first part, part A, or polyol component comprises at least one polyol, at
least
one thixotropic gelling agent, and at least one blowing agent. The polyol
component may
comprise an effective amount of~hydrophobic ingredients such that the density
of the
CA 02381872 2002-04-17
foam differs by no more than 10 lb/ft3 (0.16 kg/dm3), preferably by no more
than 5 lb/ft3
(0.08 kg/dm3) when foamed in the presence of water in comparison with being
foamed
dry. The amount of hydrophobic ingredients in the polyol component, if
present, is
typically at least about 20 wt%, preferably about 30 wt% or greater, more
preferably
about 40 wt% or greater, even more preferably about 50 wt% or greater and most
preferably greater than about 60 wt%. It is surmised that the relatively high
concentration of hydrophobic ingredients in combination with the fast
formation of a
thixotropic gel is what contributes to the characteristic that the foamable
composition is
essentially unaffected by high concentrations of water.
Preferably, the polyol component may not comprise hydrophobic ingredients such
that the density of the foam differs by no more than 5 lb/ft3 (0.08 kg/dm3),
preferably by
no more than 3 lb/ft3 (0.05 kg/dm3) when foamed in the presence of
environmental water
in comparison with being foamed dry. More preferably, the. wet foam density of
the foam
is so high that it is substantially the same as dry foam density.
For the preparation of rigid foams the useful polyol(s), in general, have a
weight
average molecular weight of from about 50 to about 4000, a functionality of
from about 2
to about 8 and a hydroxyl number, as determined by ASTM designation E-222-67
(Method B), in a range from about 14 to about 1800, preferably from about 50
to about
500, and more preferably from about 100 to about 200.
:Z0 Polyols and methods for their preparation are known. For the purpose of
the
present invention, a "polyol" is an ingredient having at least two active
hydrogen atoms.
The term "active hydrogen atom" refers to hydrogens which display activity
according to
the Zerewitnoff test as described by Kohlerin, Journal of American Chemical
Society,
Vol. 49, pp 31-81 (1927). Useful polyols include polyethers, polyesteramides,
:?5 polyesters, polythioethers, polycarbonates, polyacetals, polyolefins, and
polysiloxanes.
In some embodiments, the preferred polyols are hydrophobic including various
grades of castor oil, ricinoleate polyols (highly refined castor oil) and
derivatives thereof.
Castor oil, also known as ricinus oil, is a triglyceride (ester) of fatty
acids derived from
the seed of the castor plant. Approximately about 90% of the fatty acid
content is
:30 ricinoleic acid, an 18 carbon acid having a double bond in the 9-10
position and a
hydroxyl group on the 12'h carbon. The remainder of castor oil is made up of
dihydroxystearic acid (0.7%), palmitic acid ( 1 %), stearic acid ( 1'%), oleic
acid (3%),
9
CA 02381872 2002-04-17
linoleic acid (4.2%), linolenic acid (0.3%) and eicosanoic acid (0.3%). Castor
oil is
available in a variety of grades from several suppliers.
In some embodiments, the preferred polyols do not contain any ester linkages
in
the polyol molecule. These polyols include polyethers, polythioethers, hydroxy-
terminated polybutadienes, dimer diols, high molecular weight amine terminated
polyols
such as Jeffamine D-2000 and T-5000. More preferably, the polyols are not
hydrophobic.
Other suitable polyols include ethylene glycol, propylene glycol,diethylene
glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol and mixtures
thereof. The
polyol is present in the first part or part A at a concentration ranging from
about S% by
l0 weight to about 95% by weight, ;preferably from about 10% by weight to
about 80% by
weight, more preferably from about 20% to about 80% by weight, even more
preferably
from about 40% to about 80%, and most preferably from about 50% to about 80%
based
on the total weight of the first part (part A). It is surmised that low
molecular weight
polyol(s) act as hard segments within the polyurethane foam to increase
rigidity.
l S Alternatively or in addition to the low molecular weight polyol(s), higher
molecular
weight polyols may also be employed. Preferably, thepolyol component comprises
at
least one short chain extender to increase toughness. Short chain extenders
are known in
the art and include polyols such as ethylene glycol, dipropylene glycol, and
glycerin.
In addition to or in the alternative, higher functional polyols having more
than
:?0 two hydroxyl groups per molecule may be employed in the part A component.
Examples
include glycerol, trimethylolpropane, 1,2,4-butanetriol, 1,2,6-hexanetriol and
mixtures
thereof. The higher functional polyol may be present in the part A component
in a range
of from about 5% by weight to about 20% by weight, and preferably from about
10% by
weight to about I 5% by weight based on total weight. Such materials react to
provide
25 rigid polyurethane foams having increased crosslinked densities.
The first part (part A) of the composition of the present invention comprises
at
least one thixotropic gelling agent. Any material which will thicken the
mixture,
particularly at the interface which contacts the substrate or water, to the
extent that the
isocyanate component is substantially prevented from reacting with excess
environmental
30 water is suitable for use as the thixotropic gelling agent. Preferably, any
material that
could provide fast or instant thixotropic gelling reaction with the isocyanate
in, such as,
preferably no greater than about 5 seconds, and more preferably no greater
than about 3
CA 02381872 2002-04-17
or 2 seconds is more suitable in the application of the invention. Useful
thixotropic
gelling agents include peroxides., polya~mides, and preferably polyamines. The
polyamine
is typically a primary or secondary amine and present in the first part (part
A) component,
in some embodiments, in an amount of from about 0.1 % by weight to about 10%
by
weight, preferably from about 0.1 % by weight to about 5 % by weight, more
preferably
from about 0.5% by weight to about 2°,~0 or about 3% by weight, based
on the total weight
of the polyol component.
Surprisingly, in some preferred embodiments, when relatively large amount,
such
as, an amount of from greater than about 10 wt% to about 25 wt%, preferably
from about
12 wt% to about 15 wt%, based on the total weight of the first part, of a
thixotropic
gelling agent such as a polyamine, is used together with polyols that,
preferably, do not
contain an ester linkage or are not hydrophobic, the resultant foams show such
a high wet
foam density that it is substantially the same as dry foam density.
Upon mixing the part A and part B components, the composition typically
I5 thixotropically gels fast within 1 minui:e, preferably in about 15 seconds
or less, more
preferably in about 10 seconds or less, even more preferably in about 5 second
or less,
and most preferably, in about 3 to about 2 seconds or less, when mixed and
applied by
meter-mix application equipment, i.e., by automated application machine. The
composition also crosslinkingly gels fast, preferably, from about 10 seconds
to about 60
seconds and more preferably in no greater than about 30 seconds once it is
thixotropically
gelled.
It is surmised that in the absence of a thixotropic gelling agent, there tends
to be a
substantial difference in the foam density achieved at dry conditions in
contrast to wet
conditions. Since water is a corrunon blowing agent, the rate of expansion of
foamable
compositions typically directly relates to the concentration of water present.
Hence, as
the concentration of water increases, polyurethane compositions in the absence
of the
thixotropic gelling agent tend to froth, rather than produce a consistent
foam. It is also
surmised that the polyamine acts as a chemical thixotrope to provide an
instant
thixotropic gel once the two parts are ~~lended together. It is further
surmised that the
instant formation of a thixotropic gel, c;.g., within a few seconds, enhances
the sealing
characteristics of the resultant foam. For example, vacant spike holes often
create voids
within a railway tie that can pass completely through the tie. As the two
parts of the
I1
CA 02381872 2002-04-17
foamable composition are mixing and simultaneously injecting into the hole,
the fast or
instant thixotropic gelling action provided by the thixotropic gelling agent
such as
polyamines, preferably, polyamines which could provide the desired thixotropic
gelling,
allows the composition to more rapidly adhere to the inner surface of the
hole, as well as
more adequately seal the hole upon foaming within the void. In the absence of
the
appropriate thixtropic gelling agent, the composition is more likely to flow
through the
hole and/or cracks and provide an inadequate seal once foamed. Alternatively,
in the
absence of a thixotropic gelling agent, the ingredients for each part may be
selected such
that the composition is sufficiently high enough in viscosity upon mixing the
part A with
the part B. However, this is much less desirable since the initial high
viscosity causes the
composition to be more difficult to apply consistently, particularly at low
application
temperatures.
'The structure or type of polyamine is selected on the basis of the desired
thixotropic gel rate. In general, the polyamine may be monomeric or polymeric,
having a
functionality of 2 or greater. Linear aliphatic polyamines result in the
fastest rate of
thixotropic gelation, thus, are the most preferred, whereas cycloaliphatic
polyamines
produces a slightly slower thixotropic gel rate and aromatic polyamines even
slightly
slower. However, even the relatively "slow" aromatic polyamine results in the
formation
of a thixotropic gel in less than about 15 seconds when applied by meter-mix
equipment.
For automated application means, aliphatic and cycloaliphatic polyamines are
preferred
whereas the aromatic polyamines are preferred for hand applied application
equipment.
Preferably, the molecular weight of the polyamine ranges of from about 100
grams/mole
to about 400 grams/mole. Examples of useful polyamines include ethylene
diamine,
toluene diamine, diaminodiphenylmethane and polymethylene polyphenylene
polyamines; polyamides and aminoalcohols, for example, ethanolamine and
diethanolamine. Preferred aromatic amines include 4,4'-diamino-diphenyl
methane, 3,5-
diethyl-2,4-toluene diamine (Df,TDA), and Hardener HY-450, a 4,4'-methylene
bis (2-
ethyl-benzamine) available from Vantico. For faster thixotropic gel rates
cycloaliphatic
amines such as Amicure PACM, a bis-(p-aminocyclohexyl) methane, available from
Air
Products and Chemicals & Inc. are preferred, whereas linear aliphatic amines
such as
JeffamineD-230, D-400, and T-403 available from Huntsman Chemical Corp
(Houston,
TX) are surmised to thixotropically gel the fastest, thus, the most preferred.
12
CA 02381872 2002-04-17
In some embodiments, the foamable composition as a whole necessarily
comprises at least about 20% by weight of hydrophobic ingredients to be
foamable in the
presence of environmental water. In these instances, the amount of hydrophobic
ingredients is preferably greater than about 30%, more preferably greater than
about 40%,
even more preferably greater than about 50% and most preferably about 60 % by
weight
or greater. In the embodiments 'wherein the hydrophobic ingredients) are
primarily
contributed by the polyol portion, the first part (part A) comprises at least
about 50% by
weight, preferably at least about 60% by weight, and more preferably from
about 70% to
about 95% by weight hydrophobic ingredients, based on the total weight of part
A. The
polyol itself may be the sole hydrophobic component, as in the case wherein
relatively
high concentrations of castor oil are employed and/or additional hydrophobic
ingredients
may be employed. Examples of additives that have hydrophobic nature include
end use
performance modifiers such as monofunctional alcohol e.g. dinonyl phenol and
monofunctional long chain aliphatic hydrocarbon e.g. Alfol 1214 from Condea
Vista
Company. Additional hydrophobic agents include fuel oils such as diesel fuel,
paraffin
waxes, animal or vegetable oils, and the like.
In these embodiments, the high concentration of hydrophobic ingredients in
combination with the thixotropic gelling agent allows the foamable composition
to be
injected into an aqueous environment. For example, vacant spike holes often
contain
pooled water. Since water can act as a blowing agent, any excess amount of
water in the
environment would increase the uncontrollable foaming, thereby, decreasing the
wet
foam density of the resultant foam, especially when foaming is earned out in
the
presence of large amount of environmental water such as pooled water. As a
result, the
foam density difference between wet foam density and dry foam density could
become so
big that it can be detrimental. Foamable compositions having increased
hydrophobicity
are less likely to emulsify and/or entrap water that can also result in
reducing the foam
rigidity and adhesion characteristics.
In some preferred embodiments, the foamable composition as a whole does not
necessarily comprise a substantial amount of, or any amount of hydrophobic
ingredient
that is used solely for the purpose of foaming in the presence of
environmental water, i.e.,
any hydrophobic ingredient that., in combination with the thixotropic gelling
agent, could
substantially help the composition foam in the presence of environmental water
in the
13
CA 02381872 2002-04-17
manner as the invention does. In another word, the hydrophobic ingredients are
not
required to present in the composition so that the composition is foamable in
the
presence of a large amount of environmental water, even under water, while
still
possesses the required foam properties. In the absence of the hydrophobic
ingredient(s),
the composition can still be injected into an aqueous environment, and
exhibits excellent
foam density properties. In these instances, the composition is formulated to
still exhibit,
upon foaming under water, reduced foam density difference between wet foam
density
and dry foam density. More preferably, the composition is formulated to
exhibit very
high wet foam density that it is substantially the same as dry foam density.
Hydrophobic ingredients that are used solely for the purpose of foaming in the
presence of environmental water are different from some optional additives
which may
be in hydrophobic nature. One example of such additives is dinonyl phenol as
end use
performance modifier. Optional additives, if present, are used in small
amounts and for
the purposes) other than solely providing, in combination with the thixotropic
gelling
l5 agent, the composition the ability to foam in the presence of environmental
water in the
manner as the invention does. For example, a small amount of optional dinonyl
phenol
may be used in some preferred embodiments to improve the end use performance
of the
foam, such as the long term stability of the foam under use, e.g., when used
for repairing
the rail road spike holes under the natural environmental conditions including
very wet
:?0 environment years around.
The foamable composition of the present invention comprises at least one
blowing agent typically present in the first part (part A) component. The
preferred
blowing agent is water which is added at an amount ranging from about 0.15% by
weight
to about 1 % by weight, and preferably from about 0. l 5% by weight to about
0.5% by
:?5. weight, based on the total. weight of Part A. In many instances, the
polyol component
and/or hydrophobic ingredients contain a small concentration of residual
moisture or
water at a sufficient concentration to act as a blowing agent. Accordingly,
the blowing
agent may be inherently present and thus need not be separately added.
The foamable composition of the present invention comprises at least one
30 isocyanate, employed in the second part or part B component. Any of a wide
variety of
organic polyisocyanates compositions may be employed in the isocyanate
component,
including monomeric and/or polymeric polyisocyanates which may be linear,
branched,
14
CA 02381872 2002-04-17
cyclic aliphatic polyisocyanates, cycloaliphatic polyisocyanates, aromatic
polyisocyanates, isocyanate-terminated prepolymers, and mixtures thereof.
Representative examples include 2, 4-toluene diisocyanate (TDI), diphenyl
methane
diisocyanate (MDI), m-phenylene diisocyanate, 4-chlor-1,3-phenylene
diisocyanate, 4,4'-
S biphenyl diisocyanate, 1,5-naphthalene diisocyanate, 1,4-tetramethylene
diisocyanate, 6-
hexamethylene diisocyanate, 1,10- decamethylene diisocyanate, 1,10-
decamethylene
diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-methylene-bis(cyclohexyl
isocyanate)
and others. Further, the isocyanate compound may contain other substituents
which do
not substantially detract from the reactive natures of the isocyanate groups.
It is preferred
to use a blend of two or more isocyanates wherein at least one of the
isocyanates is
aromatic. Aromatic diisocyanates, those which have at least two isocyanate
groups
directly attached to an aromatic ring, react in the urethane reaction more
rapidly with
polyols than the aliphatic isocyanates. The preferred isocyanates are
polymeric MDIs
including polymethylene polyphenyl isocyanates such as 4,4'-methylene
bisphenyl
isocyanate, commercially available as PAPI 27, PAPI 20, PAPI 901 and PAPI94
from
The Dow Chemical Company, Midland, MI; as Rubinate M, Rubinate 9257, and
Rubinate 9258 from ICI; and as Modus MR, MR-2, and MRS-10 from Bayer.
Preferably, the isocyanate component is substantially free of isocyanate
reactants to avoid
the formation of a prepolymer that tends to substantially increase the
viscosity of the
:20 isocyanate component.
The isocyanate may be present alone in the second part (part B) component,
i.e.,
in the amount of as high as about 100% by weight. Preferably, the isocyanate
is
employed in combination with at least one plasticizes and/or other optional
additives.
Hence, the isocyanate is employed, preferably, at a concentration from about
85% by
weight to about 99% by weight, and more preferably from about 94% by weight to
about
97% by weight based on total weight of the part B.
At least one plasticizes is preferably used in the polyol component (part A)
and/or
isocyanate component (part B) to enhance the flow characteristics by reducing
the
viscosity. Suitable plasticizers include polymeric resins, elastomers, waxes,
oils and
:30 mixtures thereof. Specific examples include phthalate esters, alkyl
phosphates,
polyphenyls, di- and triphenyl compounds as well as partially hydrogenated
versions,
aromatic oils, chlorinated waxes or paraftins, adipate esters, synthetic
rubber polymer,
IS
CA 02381872 2002-04-17
natural oils, rosin and rosin derivatives, and polysulfide rubber. Preferred
plasticizers
include Eastman TXIB Plasticizer (Eastman Chemical Company, Kingsport, TN), a
2,2,4-trimethyl-1,3-pentanediol diisobutyrate plasticizer. The plasticizer may
be present
in either part in a range of from about 1 % by weight to about 25% by weight,
and
preferably from about 5% by weight to about 10% by weight, with respect to the
total
weight of each part. The addition of a plasticizer to the part A and/or part B
components
is preferred to improve the flow characteristics during the railroad tie
repair operation.
Preferably the ingredients are selected to lower the crystallization
temperature of
each component to improve the freeze-thaw stability. For example, the railroad
industry
repairs tracks year round, and fluctuations in temperature, especially during
low
temperatures, prefer that each part flow without additional heat at reduced
temperatures.
Additionally, the isocyanate used in the part B component may tend to
crystallize under
cooler temperatures so the addition of a plasticizer allows enhanced
processing
characteristics.
The viscosity of each part of the foamable composition of the present
invention is
preferably as low as possible at as low of a temperature as possible.
Accordingly, each
part of the foamable composition of the present invention has a (24 hours)
viscosity of
less than about 10,000 cPs, prefevrably less than about 5,000 cPs. more
preferably less
than about 2,000 cPs, and most preferably less than about 1,000 cPs at a
temperature of
about 50°F ( 10°C) or less. Preferably, each part of the
foamable composition exhibits the
desired viscosity at a temperature of less than about 40°F
(4°C), more preferably at less
than about 30°F (-1°C) and most preferably at about 20°F
(-7°C) or less. The foamable
composition of the invention is Imeferably applied at a temperature at which
the viscosity
is about 1,000 cPs or less. Due t:o the relatively flat viscosity curve, the
composition of
the invention is more user friendly, being able to be applied over a
relatively wide
temperature range. For the best results, the composition is applied at a
temperature from
about 70°F (21°C) to about 100°F (38°C), with
about 90°F (32°(:) being most preferred.
In order to be applied over a wide temperature range and not require any
special
handling, it is preferred that each part of the foamable composition exhibits
freeze-thaw
stability, i.e., freezing and re-thawing of each part has no substantial
detrimental effect on
the processability and/or the properties of the resulting foam. Preferably,
each part is a
stable liquid at temperatures below 30°F {-1°C), more preferably
below 10°F (-12°C),
16
CA 02381872 2002-04-17
even more preferably below 0°F (-18°C), even more preferably at
about -10°F (-23°C) or
less, and most preferably at about -20°F (-29°C) or less.
'The foamable composition of the invention also includes catalysts. The rate
of
reaction of the composition of the invention after mixing the polyol component
with the
isocyanate component can be accelerated by the incorporation of effective
amounts of
catalysts to promote the desired reactions such as active hydrogen
ato~socyanate
reaction, and isocyanurate trimerization reaction. Suitable catalysts include
those that are
known to enhance the polyol/isocyanate reaction, water/isocyanate reaction,
urethane/isocyanate reaction, urea/isocyanate reaction, and isocyanurate
trimerization
reaction. Preferably, a combination of catalysts is employed to accelerate
formation of
urethane linkages as well as the i socyanurate linkages. It is surmised that
the resultant
foam is comprised of a variety of linkages including isocyanurate, biuret and
urea
linkages rather than predominantly urethane linkages.
Catalysts are typically employed in an amount of from about 0.1 % by weight to
about 5% by weight, and preferably from about 0.3°/~ by weight to about
3% by weight,
based on the total weight of part A. Catalysts include organic amine
compounds, organo
metallic compounds, and mixtures thereof, which are typically present in the
polyol
component (Part A) for stability purposes. Further, catalysts may be employed
in
combination with various accelerators and/or curing agents such as Lewis Base
catalysts
:Z0 including ANCAMINE K.54, a tris-(dimethylaminomethyl) phenol from Air
Products
and Chemical, Inc.
Organic amine compounds based catalysts differ from the polyamine thixotropic
gelling agents with respect to the number of reactive sites present in the
molecule as well
as the concentration employed. Whereas amine based catalysts are typically
tertiary
:ZS amines, the polyamine thixotropic gelling agent is typically a primary or
secondary
amine. Hence, the polyamine thixotropic gelling agent acts as a reactant that
reacts with
the isocyanate to form the foam while amine based catalysts are added to
accelerate the
reactions of the polyol with isocyanate.
Specific examples of useful catalysts to promote the urethane reaction include
:30 dibutyltindilaurate, stannous octoate, tertiary aliphatic, and tertiary
alicyclic amines such
as triethylamine, triethanolamine, tri-n-butylamine, triethylenediamine,
alkylmorpholene.
Complex mixtures of such catalysts and modified forms may also be employed.
17
CA 02381872 2002-04-17
Commercially available examples include DABCO 33 LV (triethylene diamine in
DPG
(33/67)), and DABCO T-120 (organo tin catalyst (17.5% tin)) from Air Products
&
Chemicals, Inc. (Allentown, PA;1.
For the promotion of the isocyanurate reaction, preferred catalysts include
Polycat
41 (N, N, N', N', N", N"- hexarnethyl-1,3,5-triazine 1,3,5 (2H, 4H, 6H
tripropanamine)),
Polycat 43 (a proprietary tertiary amine), and various catalysts based on
potassium salts
of organic acids such as DABCO T-45 (potassium octonate in dipropylene glycol
(DPB)
(60/40)), DABCO K-15 (potassium octonate in DPG (70/30)), and Polycat 46
(potassium
acetate in ethylene glycol). The Polycat and DABCO catalysts are supplied by
Air
Products & Chemicals, Inc. More preferred are combinations of isocyanurate
reaction
catalysts. For example, a slower reacting trimer catalyst, i.e., isocyanurate
reaction
catalyst, such as DABCO TMR-2, DABCO TMR-3 (quaternary ammonium salts), or
DABCO TMR-30 (2,4,6-tris(dimethylaminomethyl) phenol) may be employed,
preferably, in combination with a stronger trimer catalyst. More preferably, a
combination of isocyanurate reaction catalysts such as a strong trimer
catalyst and a small
amount of urethane reaction catalyst, such as DABCO 33 LV (triethylene diamine
in
DPG (33/67)) and/or a metal based catalyst like DABCO T-120 may also be
employed.
These catalyst systems are described in more detail in U.S. Patent No.
5,556,934 issued
Sept. 17, 1996, incorporated herein by reference.
Other characteristics of the polyurethane foam can be modified with additives
commonly used in polyurethane foam compositions including fillers and
extenders as
well as ultraviolet (UV) stabilizers, antioxidants, fungicides, bactericides,
surfactants,
dyes and mixtures thereof.
The foamable composition can be made in accordance with known manufacturing
methods. The polyol component and isocyanate component are individually
prepared
using commonly available blending and mixing techniques. The two-part foamable
composition is most effectively used by mixing and applying the composition
using
automated impingement equipment that blends the two parts, or two packages at
an
appropriate blend ratio. For example, the two components can be meter mixed
together
:30 at a blend ratio based on a schoichemitric ratio of isocyanate groups
(NCO) in part B to
active hydrogen atoms (OH) in I>art A is from about 1 to about 4, preferably,
from about
1.5 to about 4, and more preferably from about 2 to about 4. Hence, excess
isocyanate is
18
CA 02381872 2002-04-17
preferred. Practically, two parts or packages are more conveniently blended at
a blend
ratio of preferably about 1: I by volume. It is an advantage that the foamable
composition
can be formulated to have a wide tolerance for the deviation of the blend
ratio due to
accidental machine malfunction., i.e., the blend ratio can be inadvertently
off the ratio
during the operation up to about 50% from the setting blend ratio, without
losing its
physical performance properties or adhesion to the substrates.
In the repair of a railroad tie, the composition of the invention is
preferably
preheated to a temperature ranging from about 80°F (27°C) to
about 120°F (49°C) and
applied into the spike hole using an automatic mixing and application unit
that is part of
a track repair process that can remove the spike and spike plate, lift or
replace the
railroad tie, and repair the spike holes using the polyurethane composition of
the
invention, followed by replacement of the spike plate and rail and respiking
the assembly
together.
The foamable composition of the present invention is also useful for
reinforcement of composite structural members including building materials
such as
doors, windows, furniture and c<~binets and for well and concrete repair. The
composition can be used to fill any unintended gaps, particularly to increase
the strength.
Structural components are formed from a variety of materials such as wood,
plastic,
concrete and others, whereas the defect to be repaired or reinforced can
appear as cuts,
gaps, deep holes, cracks, etc. The foamable composition of the present
invention is also
surmised to be useful for other applications where forming foam in an aqueous
environment is of importance as for example in the repair of cushioning for
docks.
A foam mass can be prepared by combining the polyol component, being
substantially free of urethane prepolymer, with an isocyanate component. The
foam may
be open or closed cell exhibiting a uniform cell structure which may collapse
on the
surface forming a skin. Further, the resulting foam, particularly for use in
railroad repair,
can be characterized as follows:
Useful Preferred More Preferred
Foam Density >S Ib/ft3 > 10 Ib/ft3 1 S - 30 + lb/ft3
Strength (G') > 1 X L0~' dynes/cxn2 > I X 10' dynes/cm2 > 1 X 10g dynes/cm2
Demolition Test < 40% loss < 30% loss < 20% loss
(96 hours)
19
CA 02381872 2002-04-17
Even more preferably, the foam density is from about 25 lb/ft~ to about 35
lb/ft3,
and most preferably, from about 30 lb/ft3 to about 50 lb/ft3. In preferred
embodiments,
the wet foam density does not change substantially, or remains substantially
the same
when foamed in wet environment, e.g., in the presence of environmental water
or even
under water in comparison to foaming in dry conditions. In some other
embodiments, the
difference in foam density is preferably no greater than about 10 lb/ft (0.16
kg/dm3),
more preferably no greater than about S lb/ft3 (0.08 kg/dm3), and most
preferably no
greater than about 3 lb/ft3 (0.05 kg/dm3).
Test Methods
Melt Viscosity
Melt viscosity is determined in accordance with the following procedure using
a
Brookfield Laboratories DVII-+- Viscometer. The spindle used is a RV Spindle
Set,
suitable for measuring viscosities in the range of from 10 to 100,000
centipoise. The
viscometer apparatus is lowered and the spindle submerged in the sample
tested.
Lowering is continued until the spindle line is atop the sample. The
viscometer is
turned on, and set to a shear rate that leads to a torque reading in the range
of 30 to 60
percent. Readings are taken every half minute for about 2 minutes, or until
the values
stabilize, which final reading is recorded.
The initial viscosity is tested immediately after preparation of the polyol or
isocyanate component and is often considerably higher than the viscosity after
24 hours.
The viscosity after 24 hours is representative of the viscosity during usage.
Hence
reference to viscosity refers to the 24 hour viscosity unless stated
otherwise.
Density or Dry Density is determined either by a water displacement method or
by
foaming the composition directly into an empty container of a known mass and
volume.
Wet Density is determined by the same method as the dry density except that
the
composition is foamed directly into a water bath or a water-filled container.
CA 02381872 2002-04-17
Dynamic Mechanical Analysis A temperature sweep was conducted in accordance
with
ASTM-D4440-93 on the foam employing torsion rectangular geometry and a
frequency
of 10 radians/second and a temperature ramp of 2°C/minute. The storage
modulus (G' ),
loss modulus (G " ) and tan delta were plotted over the desired temperature
range.
Ball Mill Demolition Test
The test is used to determine the resistance to erosion by impact and
abrasion.
The results are expressed as a percent loss after a period of time, typically
after 100
hours. A ball mill of the type commonly used to grind pigments is employed
having an
external dimension of approximately 5.5 " t 2 " in height having a 5.5 " ~ 1 "
diameter.
The ball mill contains thirty-three rounded cylindrical balls approximately
3/4" ~ '/4" in
height and 3/4 " ~ %4 " in diameter. Ten plugs of the sample to be tested are
prepared
which are similar in size to balls in the ball mill. The total weight of the
sample plugs is
recorded to the nearest 0.1 gram. Predust the clean ball mills balls with
small pieces of
the sample to be tested for at least 2 hours. Empty the ball mill of all dust
that can easily
be shaken out. Place the sample plugs along with dusted balls into the ball
mill. Seal
and roll the ball mill on a paint roller or similar device at 50 rpm ~ 5 rpm.
Every 12-24
hours, stop the ball mill, remove the plugs, blow off any dust that can be
removed with
compressed air and weight the samples to the nearest 0.1 gram. Determine the
percent
loss by subtracting the eroded weight from the initial weight and dividing the
difference
by the initial weight X 100%.
Examples
All the examples were prepared in accordance with the following general
~! 5 procedure:
The "polyol" as part A or first part component is prepared by adding all the
ingredients to a Cowles dissolver at room temperature and agitating until the
mixture is
completely homogeneous. For examples that include small concentrations of
catalysts or
other ingredients, it is also advantageous to make a preblend of the polyamine
and the
;SO ingredient employed in small concentrations.
If a single isocyanate is employed without any other ingredient no additional
preparation is required. In the instances when the "Iso", i.e., part B, or
second part also
21
CA 02381872 2002-04-17
comprises a plasticizer mixed or reacted with the isocyanate, the ingredients
are added to
a Cowles dissolver and agitated until the mixture is completely homogeneous.
Each part is packaged separately in an appropriate manner.
Tables I-IV represent various "polyol" or part A components whereas Table V
represents several "Iso" or part B components. The castor oil, hydroxyl
terminated
polybutadiene resin, and dinonylphenol (a monofunctional alcohol) are
hydrophobic
ingredients, whereas the polyether polyols, short chain extenders, isocyanates
and
Eastman TXIB plasticizer are not hydrophobic. The present invention
encompasses all
possible combinations of polyol components and isocyanate components in
accordance
0 with the claims.
The following observations and or physical properties were obtained upon
combining the polyol component and isocyanate component at a mix ratio of 1:1
by
volume.
All parts, percentages, amounts, ratios are by weight unless otherwise
specified.
Example 1
Polyol 1 was reacted with Iso B resulting in a foam having a wet density at
120°F
(49°C) of 16 lb/ft3 (0.26 kg/dm3) and a dry density of 27 lb/fl (0.43
kgldm3).
:?0 Example 2
Polyol 6 was reacted with uncompounded PAPI 27 isocyanate producing a foam.
Example 3
Polyol 8 was reacted with Iso H resulting in a gel time of 15 seconds and a
foam
:25 density of 23 Ib/ft3 (0.37 kg/dm3)
Example 4
Polyol 9 was reacted with Iso K and placed in a mold. The samples were put in
an oven for 2 hours at 158°F (70°C). The sample was then Azod
impact tested resulting
30 in an average strength of 0.228 ft Ib. (- blank 0.045) = 0.183 ft 1b.
22
CA 02381872 2002-04-17
Example 5
Polyol 11 was modified decreasing the castor oil content by 1 wt%, increasing
the
Dabco T-120 catalyst to 1.2 wt°/«, increasing the Ancamine K-54 to 0.4
wt%, and
replacing the HY-450 aromatic amine with Amicure PACM. The polyol had an
initial
viscosity of 1200 cPs, and a 24 hour viscosity of 250 cPs. The polyol was
reacted with
Iso K to produce a foam.
The viscosity profile for the polyol component and Iso component was as
follows:
Part A/Polyol Part B/Iso
20F (-7C) 6000 cPs 10,000 cPs
30F (-1C) 3500 cPs 5000 cPs
40F (4C) 2000 cPs 2500 cPs
50F ( 10C) 1000 cPs 1250 cPs
60F (16C) 500 cPs 500 cPs
Example 6
Polyol 14 was reacted with Iso A to produce a foam having an initial wet
density
of 24.1 lb/ft3 (0.386 kg/dm3) and a dry density of 28.1 Ib/ft3 (0.450 kg/dm3).
The next
day another foam sample was made in which the wet density was 21.1 lb/ft
(0.338
kg/dm3) and the dry density was 24.4 lb/ft~ (0.390 kg/dm3). The viscosity of
the polyol
component was 310 cPs initially and stable at 260 cPs after 1 and 2 days. The
moisture
content of the polyol component was measured to be 0.4319% initially, 0.4012%
after 1
day and 0.3649% after 2 days.
Example 7 .
Polyol 14 was modified by replacing 3 wt% of the castar oil with 3 wt%
ethylene
glycol and reacted with Iso A to produce a foam having an initial wet density
of 14.5 1b/
ft3 (0.232 kg/dm3) and a dry density of 21.9 lb/ft3 (0.350 kg/dm3). The next
day another
foam sample was made having a wet density of 20.3 Ib/ft3 (0.325 kg/dm3) and a
dry
density was 24.6 Ib/ft3 (0.394 kg/dm3). The viscosity of the Iso component was
140 cPs
initially and stable at 120 cPs after 1 and 2 days.
23
CA 02381872 2002-04-17
Example 8
The modified Polyol 14 of Example 7 was also reacted with Iso K producing a
foam having an initial wet density of 16.0 1b/ ft3 (0.256 kg/dm~) and a dry
density of 21.5
1b/ ft3 (0.344 kg/dm3). The next day another foam sample was made having a wet
density
of 16.7 1b/ ft3 (0.267 kg/dm3) and a dry density was 22.5 1b/ ft3 (0.360
kg/dm3). The
viscosity of the polyol component was consistent with Example 5 in that the
viscosity
decreased slightly within the first 24 hours and then stabilized accompanied
by a
decreasing moisture content trend. Surprisingly the change and moisture
content had
essentially no effect on the foam density.
Example 9
Polyol 16, having an initial viscosity of 270 cPs was reacted with Iso K
producing
a foam.
Example 10
Polyol 22 was reacted with Iso K producing a foam.
Example 1 I
Polyol 23 was reacted with Iso J resulting in a foam having a wet density of
18.2
1b/ ft3 (0.291 kg/dm3) and a dry density of 29.0 1b/ ft~ (0.464 kg/dm3).
Examples 12-17
Polyol 25, having a initial viscosity of 2000 cPs was reacted with
uncompounded
PAPI 27 isocyanate resulting in a 20 second gel rate. The composition was used
to
produce .foam under dry conditions with railroad tie test equipment available
from
Tamper at temperatures ranging from ambient temperature (77°F
(25°C)) to 125°F
(52°C) under a variety of test conditions as follows.
Pressure Nozzle Tem . F Density (1b/ ft31
:30 standard #20 115 (46C) 24.9 (0.398 kg/dm3)
standard #40 120 (49 C) 24.4 (0.390 kg/dm3)
standard #20 125 (52 C) 26.6 (0.426 kg/dm3)
24
CA 02381872 2002-04-17
40 lbs. #30 t 20 (49 C) 25.6 (0.410 kg/dm3)
standard #40 77 (25 "C) 31.5 (0.504 kg/dm3)
50 lbs. #30 125 (52 C) 26.7 (0.427 kg/dm3)
;?6.7 (0.427 kg/dm3)
standard #30 125 (52 C)
standard #30 125 (52 C) 25.5 (0.408 kg/dm3)
standard #20 77 (25 C) 29.2 (0.467 kg/dm3)
standard # 15 77 (25 C) 32.4 (0.518 kg/dm3)
The foam density was found to be very consistent throughout this temperature
range, particularly when the same size nozzle was employed.
Jeffamine D-400 and T'-403 were added individually to Polyol 25 and reacted
with uncompounded Papi 2027 isocyanate to decrease the crosslinking gel rate
as
follows:
Jeffamine D-400 Jeffamine T-403
1 wt-% - 14 seconds 1 wt % - 13 seconds
2% - 13 seconds 2% - 12 seconds
3% - 11 seconds 3% - 11 seconds.
Example 18
Polyol 29, having an initial viscosity of 490 cPs, was reacted with Iso F,
having
an initial viscosity of 470 cPs resulting in a foam having a density of 13.5
1b/ ft3 (0.216
kg/dm3) at 120°F (49°C) and a density of 12.7 1b/ ft3 (0.203
kg/dm3) at a higher
temperature.
Example 19-21
Polyol 31 was reacted with Iso A resulting in a foam having a wet density of
18.7
Ib/ ft3 (0.299 kg/dm3) and a dry density of 23.3 Ib/ ft3 (0.373 kg/dm3). The
viscosity of
each component was measured as follows:
25
CA 02381872 2002-04-17
Tem . F Polyol ViscosityIso Viscosity
0 ( 18C) 5600 --
(-12C) 3400 2800
(-9C) 2650 --
5 20 (-7C) -- 1200
30 (-1 C) 1700 990
40 (4C) 1230 840
60 ( 16C) 530 290
77 (25C) 285 170
10 90 (32C) 190 105
Polyol 31 was combined with 1 wt% zinc stearate and reacted with Iso A to
produce a foam having a dry density of 19.9 1b/ ft3 (0.318 kg/dm3) and a wet
density of
15 10.2 1b/ ft3 (0.163 kg/dm3).
Polyol 31 was also reacted with Iso A at ambient temperature with 60 1b of
pressure resulting in a wet density of 16.5 1b/ ft3 (0.264 kg/dm3) and a dry
density of 19.2
1b/ ft3 (0.307 kg/dm3).
Example 22
Polyol 33, having an initial viscosity of 1325 cPs was reacted with Iso K
resulting
in a gel time of 20 seconds and a density of about 25 1b/ ft3 (0.40 kg/dm3).
Example 23
. 25 Polyol 36 was reacted with Iso H resulting in a gel time of 20 second and
a foam
having an initial density of 15.6 1b/ ft3 (0.250 kg/dm3).
E~le 24
:30 Polyol 37 was reacted with uncompounded PAPI 27 to produce a foam.
26
CA 02381872 2002-04-17
Example 25
Polyol 38, having an initial viscosity of 460 cPs at ambient temperature and a
viscosity of 6400 cPs at 0°C, was reacted with Iso F, having an initial
viscosity at
ambient temperature of 440 cPs and a viscosity of 5600 cPs at 0°C. The
composition had
a gel time of 20 seconds at ambient temperature and _50 seconds at 0°C.
Example 26
Polyol 40 was reacted with Iso C resulting in a foam having a dry density at
130°F (54°C) of 20.8 1b/ ft3 (0.333 kg/dm~)
l~ 0
Example 27
Polyol 40 was reacted with Iso F resulting in a foam having a dry density at
130°F
(54°C) of 28.7 1b/ ft3 (0.459 kg/dm3) and a wet density of 21.9 1b/ ft3
(0.350 kg/dm3).
Example 28
Polyol 43 was modified with the addition of 6.2 wt% Voranol 230-660 and 2.0
wt% Amicure PACM gelling agent. The polyol component, having an initial
viscosity of
240 cPs, was reacted with Iso K to produce a less rigid foam. The dry density
was 19.3
lb/ft3 (0.309 kg/dm3) whereas the wet density was 29.3 lb/ft3 (0.469 kg/dm3).
Although
:?0 this material is surmised not to have sufficient strength to be suitable
for repair of
railroad ties, it would be suitable for other applications such as cushioning
for docks.
27
CA 02381872 2002-04-17
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CA 02381872 2002-04-17
Table V Isocyanate C:omponent
No. Ingredients
Poly BD East XIB PAPI 27 PAPI 20
605
A 5 95
B 12.5 87.5
C 10 90
D 10 90
E 5 95
F 15 85
G 16 84
H 3 97
I 5 95
J 20 80
K 5 70 25
Example 29
Polyol 44 was reacted with Iso K at 110 ° F (42 ° C) resulting
in a foam having a
wet density of 32.3 1b/ ft3 (0.518 kg/dm3) and a dry density of 32.4 1b/ ft3
(0.519 kg/dm3).
'The crosslinking gel time was about 10 to about I 5 seconds.
l0 Example 30
Polyol 45 was reacted with Iso K at 1 I 0 ° F (42 ° C) resulting
in a foam having a
wet density of 27.5 1b/ ft3 (0.441 kg/dm3) and a dry density of 27.8 1b/ ft3
(0.446 kg/dm3).
The crosslinking gel time was about 15 to about 20 seconds for a dry foam and
about 30
seconds for a wet foam, as water absorbed heat from exothermic reaction,
thereby
l5 slowing down the crosslinking gel time.
32
CA 02381872 2002-04-17
Example 31
Polyol 46 was reacted with Iso K resulting in a foam having a wet density of
30.4
lbl ft3 (0.487 kgldm3) and a dry density of 29.7 1b/ ft3 (0.476 kg/dm3). The
crosslinking
gel time for a dry foam was about 12 to about 15 seconds.
Example 32
Polyol 47 was reacted with Iso K resulting in a foam having a wet density of
22.4
1b/ ft3 (0.359 kg/dm3) and a dry density of 26.3 1b/ ft3 (0.421 kg/dm3). The
crosslinking
gel time of a dry foam was about 20 to about 25 seconds.
l0
Example 33
Polyol 48 was reacted with Iso K resulting in a foam having a wet density of
33.9
1b/ ft3 (0.543 kg/dm3) and a dry density of 34. l 1b/ ft3 (0.546 kg/dm3).
:l5 Example 34
Polyol 49 was reacted with Iso K resulting in a foam having a dry density of
37.6
1b/ ft3 (0.603 kg/dm3). The foam was then subject to heat aging at 158
° F (70 ° C) for
three weeks. The foam density measured after aging test was 37.8 1b/ ft3
(0.606 kg/dm3)
showing the very high storage stability of the foam.
Example 35
Polyol 50 was reacted with Iso K resulting in a foam having a dry density of
37.4
1b/ ft3 (0.600 kg/dm3). The foam was then subject to heat aging at 158
° F (70 ° C) for
three weeks. The foam density measured after aging test was 37.9 1b/ ft3
(0.607 kg/dm3).
Example 36
Polyol S 1 was reacted with Iso K resulting in a foam having a dry density of
37.6
1b/ ft3 (0.603 kg/dm3). The foam was then subject to heat aging at 158
° F (70 ° C) for
three weeks. The foam density measured after aging test was 39.'~ 1b/ ft3
(0.628 kg/dm3).
3~0
33
CA 02381872 2002-04-17
Example 37
Polyol 52 was reacted with Iso K resulting in a foam having a dry density of
37.6
Ib/ ft; (0.603 kg/dm3). The foam was then subject to heat aging at 158
° F (70 ° C) for
three weeks. The foam density measured after aging test was 37.9 Ib/ ft3
(0.607 kgldm3).
Example 38
Polyol 53 was reacted with Iso K resulting in a foam having a wet density of
27.8
1b/ ft3 (0.446 kg/dm3) and a dry density of 32.2 1b/ ft3 (0.5 I 6 kg/dm3).
Example 39
Polyol 54 was reacted with Iso K resulting in a foam having a wet density of
28.5
1b/ ft3 (0.457 kg/dm3) and a dry density of 26.9 1b/ ft3 (0.431 kg/dm3).
Example 40
l 5 Polyol 55 was reacted with Iso K resulting in a foam having a wet density
of 29.7
1b/ ft3 (0.476 kg/dm3) and a dry density of 26.9 1b/ ft3 (0.431 kg/dm3).
34
