U.S. patent number RE43,432 [Application Number 12/581,976] was granted by the patent office on 2012-05-29 for polyurethane foam composition.
This patent grant is currently assigned to Dow Global Technologies LLC. Invention is credited to Robert G. Braun, Jess M. Garcia, Deborah A. Schutter.
United States Patent |
RE43,432 |
Braun , et al. |
May 29, 2012 |
Polyurethane foam composition
Abstract
Single component compositions for making a moisture-cured
polyurethane foam are disclosed. Foam produced from the
compositions of the present invention produce very low foaming
pressure due to their 60-95 percent open-cell content. After these
compositions are applied and cure, they form a permanent seal
around the perimeter of installed fenestration products.
Inventors: |
Braun; Robert G. (Melbourne
Beach, FL), Garcia; Jess M. (New Lenox, IL), Schutter;
Deborah A. (Minooka, IL) |
Assignee: |
Dow Global Technologies LLC
(Midland, MI)
|
Family
ID: |
22838085 |
Appl.
No.: |
12/581,976 |
Filed: |
August 8, 2001 |
PCT
Filed: |
August 08, 2001 |
PCT No.: |
PCT/US01/24903 |
371(c)(1),(2),(4) Date: |
March 19, 2003 |
PCT
Pub. No.: |
WO02/12367 |
PCT
Pub. Date: |
February 14, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60223817 |
Aug 8, 2000 |
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Reissue of: |
10344073 |
Aug 8, 2001 |
6894083 |
May 17, 2005 |
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Current U.S.
Class: |
521/159; 521/170;
521/174; 521/172 |
Current CPC
Class: |
B65D
83/207 (20130101); C08G 18/2081 (20130101); C08G
18/4812 (20130101); C08G 18/4018 (20130101); C08G
18/4816 (20130101); C08G 18/12 (20130101); C09K
3/1021 (20130101); C08G 18/12 (20130101); C08G
18/307 (20130101); C08G 2110/0008 (20210101); C08G
2101/00 (20130101); C08G 2350/00 (20130101); C08L
83/00 (20130101) |
Current International
Class: |
C08G
18/00 (20060101) |
Field of
Search: |
;521/159,170,172,174 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2221015 |
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Jun 1998 |
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CA |
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0 850 964 |
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Jul 1998 |
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EP |
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Other References
International Search Report (PCT/US01/24903), 2002. cited by other
.
Jorgenson, M.W., et al., Silicone Surfactant Structural Requirments
in Rigid Polyurethane Foams, Proceedings of the Society of the
Plastic Technology, 1983, pp. 474-478. cited by other .
Snow, S.A., et al., The Science of Silicone Surfactant Application
in the Formation of Polyurethane Foam, Surfactant Science, 1999,
pp. 137-158. cited by other.
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Primary Examiner: Heincer; Liam
Parent Case Text
This application claims the benefit of Domestic Application No.
60/223,817 filed Aug. 8, 2000.
Claims
What is claimed is:
1. A single component .Iadd.polyurethane .Iaddend.foam forming
composition comprising a mixture of (a) prepolymers containing free
isocyanate groups in the range of 12 to 17 percent by weight, based
on the .Iadd.weight of the .Iaddend.prepolymer, which is produced
by reacting a polyisocyanate with a polyol blend comprising a first
polyol that is a triol having a molecular weight .Iadd.of in the
range of .Iaddend.from .[.500 to 3000.]. .Iadd.600 to 2,500
.Iaddend.and a second polyol .Iadd.that .Iaddend.is a diol, triol
or .[.a mixture.]. .Iadd.mixtures .Iaddend.thereof having a
molecular weight .Iadd.in the range .Iaddend.of from .[.4,000 to
12,000.]. .Iadd.6,000 to 10,000, .Iaddend.wherein the first
.[.to.]. .Iadd.polyol and the .Iaddend.second polyol are present in
a parts by weight ratio .Iadd.in the range .Iaddend.of .[.form.].
.Iadd.from .Iaddend.1.6 to 1:2; (b) a blowing agent.Iadd.; and (c)
from 0.5 to 4 percent by weight a surfactant comprising the
reaction product of a poly(alkyl siloxane) and a poly(alkylene
oxide) copolymer, where the alkylene oxide are ethylene oxide,
propylene oxide or butylene oxide, based on the total weight of the
single component polyurethane foam forming composition, wherein
said polyurethane foam forming composition forms an open-cell
structure foam having open cells in the range of from 60% to
95%.Iaddend..
.[.2. The composition of claim 1 further comprising from 0.5 to 4
percent by weight, based on the total weight of the composition, of
a polydimethyl siloxane polyoxyalkylene copolymer
surfactant..].
3. The composition of claim .[.2.]. .Iadd.1 .Iaddend.wherein the
surfactant comprises 1 to 3 percent by weight of the
composition.
4. The composition of claim .[.2.]. .Iadd.1 .Iaddend.wherein the
surfactant has a molecular weight of less than 30,000.
5. The composition according to claim 1, wherein the polyisocyanate
is selected from the group consisting of aliphatic, cycloaliphatic,
aryliphatic, and aromatic polyisocyanates.
6. The composition according to claim 5, wherein the polyisocyanate
is an aromatic polyisocyanate selected from a diphenylmethane
diisocyanate, polyphenyl polymethylene isocyanate or a combination
thereof.
7. The composition of claim 1 wherein the blowing agent is a
hydrocarbon, a fluorocarbon, a chlorocarbon, a chlorofluorocarbon
or a mixture thereof.
8. The composition of claim 7 wherein the blowing agent is a
hydrocarbon selected from isobutane, propane, dimethylether or a
mixture thereof.
9. The composition of claim 1 wherein the composition contains
additional auxiliary agent selected from amine .[.catalysis.].
.Iadd.catalysts.Iaddend., tin .[.catalyst.]. .Iadd.catalysts
.Iaddend.or flame retardants.
.[.10. The composition of claim 1, wherein the triols and diols
together comprise a secondary hydroxyl functionality of at least
about 50 percent..].
11. The composition of claim 4 wherein the second polyol is a
diol.
12. The composition of claim 4 wherein the second polyol is a
triol.
13. A moisture-cured polyurethane foam prepared from a composition
of .[.any one of claims.]. .Iadd.claim .Iaddend.1.
14. .[.A.]. .Iadd.The .Iaddend.foam of claim 13 wherein the foam
has an open cell structure of from 60 to 95 percent open cells.
.[.15. A method for the production of a polyurethane foam
comprising supplying to a valved vessel a mixture comprising an
isocyanate-terminated prepolymer and a blowing agent wherein the
prepolymer is obtained by reacting a polyisocyanate with a polyol
mixture comprising a first polyol that is a triol having a
molecular weight from 500 to 3,000, and a second polyol that is a
diol, triol or mixture thereof having a molecular weight from 4000
to 12,000, wherein the first and second polyols are present in a
parts by weight ratio of from 1:6 to 1:2, allowing the mixture to
reach equilibrium, adding pressure if needed, maintaining the
pressure during storage and releasing the mixture outside the
vessel to produce a foam which as a cell structure of from 60 to 95
percent open cells..].
.[.16. The method of claim 15 wherein the mixture is dispensed from
the vessel using a gun-like dispenser with or without a straw
extender tip or with a trigger-straw dispenser..].
17. A fenestration assembly comprising the polyurethane foam of
claim 13 applied and cured around the perimeter of an installed
fenestration product.
18. Building materials comprising the polyurethane foam of claim
14.
19. A transportation craft comprising the foam of claim .[.13.].
.Iadd.14.Iaddend..
Description
The present invention relates generally to the field of foamable
polyurethanes. More specifically, the invention relates to single
component composition for producing a moisture cured polyurethane
foam where the foam has from 60 percent to 95 percent open-cell
content.
Polyurethane foams have been known for many years. These foams are
useful and have found their way into many industries. Most
polyurethane foams are inherently hydrophobic and therefore are
useful as insulation in moist or wet environs. In addition,
polyurethane foams are known to provide excellent air barriers and
are often used as both sealants and adhesives.
One particularly useful application of polyurethane foams is in the
door and window installation industry. The improper installation of
fenestrations (for example, windows, doors, skylights, etc.) in
homes and office buildings can result in extreme and quantifiable
energy losses. It was discovered that foamable polyurethane
systems, particularly single-component systems, could easily be
directed into the rough opening gap (void space between the wall
and the inserted fenestration) to insulate and create airtight
seals. Generally such single-component systems are storage stable
foamable mixtures, under pressure, of a polyurethane prepolymer,
blowing agents and auxiliary components for producing a
polyurethane foam.
As the polyurethane composition is dispensed from containers, it
immediately expands to fill cavities, such as the gap formed
between the window and the rough opening. The expansion of the
composition exerts a force against the adjacent construction
materials as it further expands and cures. So long as the
construction materials are strong enough, the foaming pressures
have virtually no perceptible effect. However, problems have been
reported when expandable polyurethane foams have been used to
install fenestrations, particularly window assemblies made from
aluminum and vinyl components. In these fenestration constructions,
the foams have been known to exert enough foaming pressure (outward
force) to cause extensive distortion of, for example, the window
frames along their perimeters. Such distortion can also be called
deflection. The greater the foaming pressure, the greater the
deflection that will occur along the length of the window frame.
Many window manufacturers recommend that 1.59 mm ( 1/16'' or 0.0625
inches) is the maximum allowable deflection per side for window
framing materials. Any greater deflection will impact the window
performance in terms of ease of opening. Deflection in excess of
this value will make opening difficult and in severe cases will
prevent the window from opening and may adversely affect the air
seal and energy efficiency of the window.
Prior art foams have been shown to have foaming pressures in the
range of from 11 to 23 kPa (1.6 to 3.4 psi) when measured in a
simulated rough opening cavity, which can result in the deflection
of a typical vinyl window beyond the manufacturer's
recommendations.
Within an hour or so of dispensing the foam, the foam will expand
an additional amount. It has been commonly believed that this "post
dispensing expansion" is a type of foam expansion that produces
enough force to cause fenestration frame deflection. Thus, the
fenestration manufacturers have tended to prefer, and in some
instances specify that only "minimally expanding" foam sealants are
to be used to install windows and doors.
In many cases, frame deflection is due to human error, as too much
foam is applied to the cavity space between the wall and the frame
interior. Properly applied, the foams should not cause excessive
deflection. However, there is a tendency to overfill or completely
fill cavities, which results in fenestration frame deflection.
Single component polyurethane foam sealants still offer the best
option in terms of a cost-effective, easily applied insulation
material that is moisture resistant and provides an excellent air
barrier. Therefore a dispensable, polyurethane foam sealant that
can exert a predictable, and relatively low force on adjacent
surfaces regardless of how it is applied, and that also will not
deform window frames, is highly desirable.
The invention is the use of a single component foam composition to
produce open cell polyurethane foam wherein the foaming pressure is
less than 11 kPa (1.6 psi) when measured in a simulated
rough-opening cavity. In another aspect, the invention is to a
polyurethane foam produced from such a composition wherein the foam
has an open cell content of from 60 to 90 percent.
The present invention is a single component foam forming
composition comprising a mixture of
(a) prepolymers containing free isocyanate groups in the range of
12 to 17 percent by weight, based on reactive components in the
foamable composition, which is produced by reacting a
polyisocyanate with a polyol blend comprising a first polyol that
has functionality from 2 to 4 and having a molecular weight from
500 to 3000 and a second polyol that has a functionality of from 2
to 4 and a molecular weight of from 500 to 12,000 wherein the first
to second polyol are present in a parts by weight ratio of form 1:6
to 1:2;
(b) usual adjuvants for polyurethane foams; and
(c) a blowing agent.
An additional embodiment of the present invention is the above
composition wherein the composition further contains from 0.5 to 4
percent by weight of a poly siloxane polyoxyalkylene
surfactant.
In a further embodiment, the present invention is to a single
component polyurethane foam composition comprising a
polyisocyanate, and a first and a second polyol (triols and/or
diols) provided in a ratio of from 1:6 to 1:2, preferably from 1:5
to 1:2, and more preferably from 1:4 to 1:2. An excess of
isocyanate is reacted with the polyol blend (which also contains
additional components, such as catalysts, surfactants, and fire
retardants) in the presence of a blowing agent to form a
polyurethane prepolymer. When dispensed from the container, the
frothed prepolymer reacts with atmospheric moisture to form an open
cell foam having 60 percent to 95 percent open cells.
In accordance with a further embodiment, the present invention
relates to a single component polyurethane foam composition
comprising an aromatic polyisocyanate, preferably based on
diphenylmethane diisocyanate (MDI) and most preferably a
polymethylene polyphenyl isocyanate (PMDI), and a first and a
second polyol provided in a ratio of from 1:6 to 1:2. The first
polyol preferably has a molecular weight range of from 500 to 3000.
The second polyol preferably has a molecular weight (MW) range of
from 4000 to 12,000. The composition makes an open cell foam having
from 60 percent to 95 percent open cells.
In an embodiment the first polyol is a triol and the second polyol
is a diol. In another embodiment, the first and second polyols are
triols. In yet another embodiment, the first polyol is a triol and
the second polyol is a blend of diol and triol.
In yet a further embodiment, the present invention relates to a
system and device for dispensing a composition for a moisture-cured
single component polyurethane foam comprising a container
containing a polyurethane prepolymer composition wherein the
dispensed polyurethane prepolymer reacts with atmospheric moisture
to form a polyurethane foam having from 60 percent to 95 percent
open-cells.
In a another embodiment, the device of the present invention
further comprises a dispenser of the straw-trigger/valve, or
dispensing gun/valve type where the dispensing gun may include the
addition of a straw tip extender.
The present invention also relates to a method for applying around
a fenestration installation a polyurethane foam that expands, yet
generates low forces on the fenestration assembly during foam
application and curing. A polyurethane prepolymer composition is
provided comprising a polyisocyanate and a polyol composition
wherein the polyol has a functionality of from 2 to 4 and a
molecular weight of 500 to 12,000 where the ratio of isocyanate to
polyol is from 1:1.2 to 1:0.8 parts by weight based on reactive
components in the foamable composition. A polyurethane prepolymer
composition is provided comprising a polyisocyanate, a first polyol
which is a 500 to 3000 MW triol; a second polyol which is a 4000 to
12000 MW diol or triol, said first and second polyol provided in a
ratio of isocyanate to polyol blend of from 1:1.3 to 1:0.8,
preferably from 1:1.2 to 1:0.7 parts by weight.
The isocyanate and polyol blends are introduced into a container
that is then sealed with a valve in place. The container is then
charged with a blowing agent that dissolves into the mixture and
acts to pressurize the container and form the cell structure of the
moisture-cured foam. An excess amount of isocyanate of the
stoichiometric ratio of isocyanate-to-polyol (NCO:OH) is reacted to
form a polyurethane prepolymer with from 12 percent to 17 percent
free NCO, and preferably from 13 percent to 15 percent free NCO.
Once the reaction is complete (usually about 24 hours), a dispenser
is then attached to a valve on the container. Upon activating the
valve the composition is released from the container and delivered
through the dispenser. The prepolymer reacts with atmospheric
moisture to form an open-cell polyurethane foam structure of 60
percent to 95 percent open-cells.
FIG. 1 shows the foam of the present invention dispensed into a
rough opening gap between a window frame and a wall via a container
and trigger-straw/valve dispenser representing one preferred
embodiment.
FIG. 2 is an enlarged view of one type of trigger-straw/valve
dispenser of FIG. 1.
FIG. 3 shows the foam of the present invention dispensed into a
rough opening between a window frame and a wall via a container and
dispenser representing another preferred embodiment.
FIG. 4 shows the foam of the present invention dispensed into a
rough opening between a window frame and a wall via a container and
dispenser representing a further preferred embodiment.
FIG. 5 shows a cut away view of the wall showing the foam of the
present invention being applied to the rough opening gap between a
window frame and a wall.
According to the present invention, it has now been discovered that
a moisture-cured single component polyurethane foam sealant,
independent of the dispensing mechanism, can be employed usefully
as a window sealant, having all of the desirable characteristics
normally associated with such foams. In addition, the polyurethane
foam of the present invention does not exert an excessive foaming
force as it expands and cures. It has now been discovered that foam
expansion in polyurethane foams does not necessarily directly
relate to the foam's foaming force during cure. So long as the foam
maintains an open-cell structure of from 60 percent to 95 percent
open-cell, the foam performs equivalently to, or better than, known
single component polyurethane foam sealants, with respect to foam
expansion and air barrier characteristics, while exerting a much
lower foaming force. This desirable combination of polyurethane
foam properties results in greatly reduced fenestration frame
deflection.
The high percentage open-cell character, along with the greater
flexibility and resilience of the aerosol sealant foams of the
present invention, are achieved by using surfactants normally
associated with rigid form, high resilience molded foam or high
resilience slab foam production and specifically structured polyols
in specific proportions in combination with other components. In
general, it has been recognized in the art that manufacturing any
type of foam with high open cells is difficult. Processing
variables can often lead to too high or too low an open cell
content. This leads either to foam shrinkage (open cell content too
low) or foam collapse or coarse cells (open cell content too high).
According to one aspect of the present invention, the proper
formulation ratio and polyol type to produce a 60 percent to 95
percent open-celled foam has been conclusively determined, and
results in a foam that has an exceedingly low foaming pressure
regardless of the selected dispensing method. In another aspect,
the selection of the proper surfactant in the formulation will
produce the 60 to 95 percent open cell content required.
Traditionally, expandable polyurethane sealant foams have been
produced by dispensing single component foam compositions using
straw/trigger assemblies and gunlike attachments with trigger
mechanisms. The advantage of the gun mechanism is improved control
of flow, greatly improved product "reuse", and instant shut off
effected at the tip. This instant shut off eliminates post foam
dripping after shut off that occurs with both the straw/trigger
dispenser and the gun dispenser with an attached straw tip
extender. Each of these dispensers is designed to attach to the
aerosol valve of the container. Straw extenders are often used with
the gun-like attachments to reach into areas that are difficult to
access with the regular dispenser tip. Such extenders for the gun
mimic the ability of the trigger straw assemblies to reach more
difficult areas, and can extend the tip by about 5 cm. (2 in.) or
more. The present inventors have appreciated that the use of
extenders directly impacts the properties of the dispensed foam.
For example, it has been appreciated that known single component
compositions, when released through an extender, result in a
dispensed foam having a greater wet density, as compared to the
same foam being dispensed without an extender. It is known that the
flow dynamics within the straw extender leads to a denser dispensed
product. Therefore, the use of extenders causes more product to be
dispensed into the same volume cavity. In addition, known foams
dispensed via straw extenders display significantly greater forces,
resulting in fenestration frame deflection compared to the same
foam dispensed directly from the gun tip.
By contrast, the foams of the present invention exhibit foaming
forces that remain relatively constant regardless of how they are
dispensed; that is with or without straw tip extenders. This
constancy is evidenced by the lack of resulting fenestration frame
deflection. This predictable, low foaming force insures against the
adverse effects of over filling cavities, for example, in the
window/door industry, which avoids the fenestration distortion and
deflection problems described above. Therefore, the ability to use
dispensing extenders allows the user to reach into cavities and
installation spaces as desired without worrying about fenestration
frame deflection.
The open-cell content of foams can be determined according to ASTM
D2856-94, Vol. 08.02. The preferred foams of the present invention
have an open-cell content of from 60 percent to 95 percent, more
preferably from 75 percent to 95 percent, and most preferably from
85 percent to 95 percent.
In general, the process of the present invention uses variations of
single component polyurethane chemistry. However, for the first
time, the applicants recognized the relationship between the use of
surfactants, and the molecular weights of polyols along with the
required polyisocyanates, suitable catalysts, diluents, fire
retardants and other additives, in controlling open cell formation
to predictably achieve a foam useful for air barrier and sealant
uses. In addition, the foams of the present invention do not
generate potentially damaging forces to a fenestration
assembly.
The polyols are caused to react with an excess polyisocyanate such
that the prepolymers contain free isocyanate groups. Generally the
prepolymers have an isocyanate content of 12 to 17 percent by
weight, based on reactive components in the foamable composition.
Preferably the prepolymers have an isocyanate content of 13 to 15
percent by weight of the prepolymer. The reaction between the
polyol and isocyanate is normally effected in the temperature range
up to 100.degree. C., preferably at normal temperature to only
moderately elevated temperatures.
Suitable organic polyisocyanates are the aliphatic, cycloaliphatic,
aryliphatic and preferably aromatic polyisocyanates including, but
not limited to alkylene diisocyanates having from 4 to 12 carbon
atoms in the alkylene moiety, such as 1,12 dodecane diisocyanate,
2-methylpentamethylene 1,5-diisocyanate, tetramethylene
1,4-diisocyanate, hexamethylene 1,6-diisocyanate; cycloaliphatic
diisocyanates such as cyclohexane 1,3- and 1,4-diisocyanate,
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane
(isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene
diisocyanate and the corresponding isomer mixtures 4,4'-, 2,2'- and
2,4'-dicyclohexylmethane diisocyanate and the corresponding isomer
mixtures, and preferably aromatic diisocyanates and polyisocyanates
such as 2,4- and 2,6-toluene diisocyanate and the corresponding
isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane
diisocyanates, polymethylene polyphenyl isocyanates, mixtures of
4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and
polymethylene polyphenyl isocyanates (PMDI), and mixtures of the
PMDI and toluene diisocyanates. Particularly preferred for
inclusion with the triol and diol polyols mixture is polymethylene
polyphenyl isocyanate.
The isocyanates may be modified as would be readily understood by
those skilled in the field of polyurethane foam chemistry, so long
as the selected isocyanates react with the polyol mix
(approximatelyl 1:4 ratio of triols to diols parts by weight) to
create a final foam product that has 60 percent to 95 percent open
cells. Preferably, the isocyanate is present in the final
composition of the present invention in an amount of from 30 to 40
weight percent. Further, the isocyanate is present in a comparative
ratio to the polyols in the range of from 7:1 to 14:1 NCO to OH
equivalents, and preferably from 9:1 NCO to OH equivalents.
To achieve the open cell content of the present invention, it has
been surprisingly found that surfactants generally used for making
rigid closed cell foam in a two-component system will give the
desired open cell content produced from the single component
system. Useful surfactants include silicone type compounds commonly
used in high resilience molded foam, high resilience slab stock
foam and rigid type polyurethane foam formulations. In general such
surfactant are the reaction product of a poly(alkyl siloxane),
preferably a poly(dimethyl siloxane) compound and a poly(alkylene
oxide) copolymer, where the alkylene oxides are ethylene oxide,
propylene oxide or butylene oxide. Such surfactants are well known
in the art, see for example Surfactant Science Ser. 86 (Silicone
Surfactants), 137-158 (1999). For the present invention, the useful
surfactants have a molecular weight of less than 30,000. Preferably
the molecular weight is less than 20,000 and more preferably 15,000
or less.
An example of preferred surfactants are poly(dimethyl siloxane)
polyoxyalkylene block copolymers of the general formula
##STR00001## In this general formula n, m, x and y are integers
which can assume a wide numeric range to give the desired molecular
weight as described above. Preferably the surfactant has less than
50 siloxane units [(Si(CH2)--O] and the polyether chains are less
than 1500 g/mol. The percent silicone oxide, copolymer content,
etc. can be varied to affect the properties of the surfactant, see
for example Silicone Surfactant Structural Requirements in Rigid
Polyurethane Foams, Proceedings of The Society of the Plastics
Industry, 474-478, 1983.
When added at the appropriate level in either the polyol blend or
the reaction mixture, these surfactants will produce open cell foam
instead of closed cell foams in combination with the polyol blend
of the present invention. The surfactants provide stability to the
foam's cell structure during dispensing, curing and the
post-expansion processes, which occurs as a result of CO.sub.2
generated by the reaction of the free isocyanate with atmospheric
moisture. The surfactants further assist in the control of the open
cell to closed cell ratio that, in turn, provides dimensional
stability and affects the foaming pressure of the final cured foam.
Examples of commercially available surfactants suitable for use in
the present invention include, those typically used in closed cell
rigid foam applications such as DC 197, DC 193, B 8853, B 8462, B
8407, B 8404, L-5340, L-5420, L-6900; surfactants used for high
resilience molded foam such as, DC 5164, DC 5169, B 8638, B 8681;
and surfactants used for high resilience slab foam such as DC 5043,
B 8707, and B 6881. The DC series of surfactants is available from
Air Products, the B series is available from Goldschmidt and the
L-series is available from OSI Specialties. Most preferred are the
commercially available rigid type silicone surfactants. Most
preferred are surfactants such as L-5340, L-5420, DC-197 and
DC-193. The surfactants are present in the composition mixture of
the present invention in an amount of from 0.5 to 4.0 parts by
weight, preferably 1 to 3; and more preferably about 2 parts by
weight.
The polyol composition is a polyether and/or polyester known for
the production polyurethane elastomeric adhesives and sealants,
rigid, semi-rigid and froth foams. The polyether/polyester polyols
may also contain amine groups. The molecular weight of the polyol
is between 500 and 12,000 number average molecular weight and a
functionality of from 2 to 4, preferably from 2 to 3.
The polyols are produced by techniques known in the art. For
example, suitable polyesters are produced from polycarboxylic acids
and polyfunctional alcohols having from 2 to 12 carbons atoms.
Examples of polycarboxylic acids include glutaric acid, succinic
acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid or
terephtalic acid. Examples of polyfinctional alcohols include
ethylene glycol, propanediol, butane, and hexane diol.
Polyether polyols can be obtained in conventional manners by
reacting alkylene oxides, such as ethylene, propylene or butylene
oxide, with an initiator having two active hydrogen atoms for a
diol and with an initiator having three active hydrogen atoms for a
triol. Examples of suitable initiators include ethylene glycol,
diethylene glycol, propylene glycol, dipropylene glycol,
tripropylene glycol, 1,4-butanediol, 1,6-hexane diol;
cycloaliphatic diols such as 1,4-cyclohexane diol, glycerine,
timethanoyl propane and triethanolamine. Catalysts for the
polymerization can be either anionic or cationic with catalysts
such as KOH, CsOH, boron trifluoride, or a double cyanide complex
(DMC) catalysts such as zinc hexacyanocobaltate. Preferred polyols
are those obtained using propylene oxide or a combination of
propylene and ethylene oxide.
Preferably the polyol is a blend of a first and second polyether
polyol. In one embodiment, the first polyol is one or more triols
and second polyol is one or more diols that, combined, preferably
have a secondary hydroxy functionality of at least about 50
percent. The triols preferably have molecular weight (MW) range of
from 500 to 3000 MW, more preferably from 600 to 2500 MW, and most
preferably from 800 to 1500 MW. The diols preferably have a
molecular weight range of from 4000 to 12,000 MW, preferably from
5000 to 10,000 MW, and most preferably from 6000 to 10,000 MW. Most
preferably the triol is about a 1000 MW molecule and the diol is
about an 8000 MW molecule.
In a second preferred embodiment, the second polyol is one or more
triols having a secondary hydroxy functionality of at least about
50 percent and a molecular weight range from 4,000 to 12,000 MW,
preferably from 5000 to 10,000 MW, and most preferably 6000 to
10,000 MW. More preferably, when the second polyol is a triol, such
triol has a MW of about 9300.
In still another embodiment, the second polyol is combination of
diol and triol as within the MW described above.
Preferably, the polyols are selected such that they are in a ratio
of approximately 1:4 first polyol:second polyol. Most preferably,
the first polyol is an hydroxy terminated poly(oxyalkylene) triol
and the second polyol is an hydroxy terminated poly(oxyalkylene)
diol or triol. In combination, the polyols preferably are present
in the composition of the present invention in an amount of from 35
to 40 parts by weight.
The mixture further comprises a catalyst, such as an amine
catalyst, to accelerate the reaction of the compounds in the
mixture containing reactive hydrogen atoms and hydroxy groups. The
preferred amine catalyst may comprise a primary, secondary or
tertiary amine, with tertiary amine catalysts being particularly
preferred. In addition to initiating the reaction between hydroxyl
or active hydrogen and the isocyanate it is essential to accelerate
the post moisture cure of the formulation to finished foam once the
product is dispensed and used. Therefore many amine catalysts will
be suitable, although tertiary amines are preferred including, but
not limited to dimethylethanol amine (DMEA),
tetramethyliminobispropyl amine (Polycat 15),
N,N-dimethylcyclohexyl amine (DMCHA), tetraethylenediamine
(Dabco/TEDA), etc. Other suitable compounds include organometallic
compounds such as tin mercaptide, dibuyltin dilaurate (DBTDL),
etc.
Most preferably, the amine catalyst is a dimorpholine compound such
as dimorpholinopolyethylene glycol (PC Cat 1 KSC),
2,2'-dimorpholinodiethylether (DMDEE), with
2,2'-dimoipholinodiethylether being particularly preferred. The
dimorpholine catalysts are preferably present in the compound of
the present invention in an amount of from 0.45 to 0.90 parts by
weight, and most preferably 0.55 to 0.7 parts by weight.
To make the polyurethane foam mixture of the present invention
acceptable from a regulatory standpoint, for example, to be used as
insulation with electronics, appliances or in conjunction with
building materials, flame retardants are incorporated. Useful flame
retardants include, without limitation, any compound with flame
suppression properties that can be dissolved or dispersed in the
polyurethane foam. These include compounds such as chlorinated or
brominated phosphates, phosphonates, inorganic oxides and
chlorides. Preferably, the flame retardant is a soluble liquid such
as triethyl phosphonate, pentabromodiphenyl oxide, and most
preferably is tri(1-methyl-2-chloroethyl) phospohate. The flame
retardants are preferably present in an amount of from 5 to 15
parts by weight.
The composition mixture may be formulated such that the foamed
product may be made to cure to any useful color or shade as would
be readily apparent to one skilled in the field of polyurethane
foam formulations. For example, to create foam with color,
colorants may be used.
Additional reactive components can be added to the composition such
as silyl-terminated substances, which are compatible yet do not
react in the can with the prepolymer polyurethane product. These,
however, will also moisture cure independently once dispensed from
the container thus producing an interpenetrating polymeric network.
Such formulations have also been found to exhibit exceptional
properties and suitable open cell contents.
A crosslinking agent or chain extender may be added, up to 5
percent by weight of the composition if necessary. The crosslinking
agent or the chain extender includes low-molecular polyhydric
alcohols such as ethylene glycol, diethylene glycol,
1,4-butanediol, and glycerin; low-molecular weight amine polyol
such as diethanolamine and triethanolamine; polyamines such as
ethylene diamine, xylenediamine and methylene-bis(o-chloroaniline).
Also small quantities (less than 5 percent by weight) of any
convention rigid foam polyol can be added to the composition to
increase crosslinking and to modify the foam modulus.
Once the polyisocyanate and polyol blend are combined in the
receptacle, usually a pressurizable container such as a metal
aerosol can, the can is sealed with an aerosol valve prior to
introducing a blowing agent. Useful blowing agents preferably
include physical blowing agents. Such physical blowing agents are
preferably gases that are inert toward the organic, modified or
unmodified polyisocyanates. Such blowing agents preferably have
high vapor pressures and boiling points typically below about 1
00.degree. C., and most preferably from -50.degree. C. to
30.degree. C. at atmospheric pressure, so that they evaporate and
form the cell structure after the foam is dispensed. Examples of
suitable blowing agents includes alkanes, such as heptane, hexane
and n-and isopentane, preferably technical grade mixtures of n- and
isopentanes and n- and iso butane and propane, cyclohexane,
cyclopentane; ethers, such as furan, dimethyl ether and diethyl
ether; ketones, such as acetone and methyl ethyl ketone; alkyl
carboxylates, such as methyl formate, dimethyl oxalate and ethyl
acetate; and halogenated hydrocarbons, such as methylene chloride,
dichloromonofluoromethane, difluoromethane, chlorodifluoromethanes,
difluoroethane, tetrafluoroethane, chlorofluoroethanes, 1,1
-dichloro-2,2,2-trifluoromethane, 2,2-dichloro2-fluoroethane and
hepafluoropropane, and mixtures thereof. Most preferred for the
compositions of the present invention is an
isobutane/propane/dimethyl ether mixture in combined amounts of
from 11 to 16 parts by weight, and preferably about 13.2 parts by
weight. The most preferred formulation is 67 to 70 parts by weight
isobutane, 10 to 12 parts by weight propane, and 19 to 21 parts by
weight dimethylether (DME).
The composition of the present invention is made by combining the
polyols and additional compounds including an amine catalyst, a
flame retardant, surfactants, and optional colorants into a premix.
This polyol blend is added to the isocyanate. Finally an acceptable
blowing agent is introduced to the mixture to aid in forming the
cell structure of the foam
The composition may be dispensed via any useful dispensing systern.
In one preferred embodiment of the present invention, the preferred
polyurethane prepolymer is under pressure, such as, for example in
a valved aerosol can. In a further preferred embodiment, the
present invention relates to a preferred polyurethane prepolymer
formulation in a valved aerosol can with a dispenser attached to
the can for dispensing the polyurethane composition into a foamed
state. According to the present invention, one preferred dispenser
is of the type that is the subject of U.S. Pat. Nos. 6,032,830;
5,887,756; 5,615,804 and 5,549,228.
In a still further embodiment, the present invention contemplates
adapting the dispenser with an extender. The extender is preferably
an elongated cylindrical, strawlike attachment temporarily or
permanently affixed to the end of the dispenser. The straw may be
any useful length, preferably from 8 to 25 cm (3 to 10 inches)
long.
The present invention now will be described more fully hereinafter
with reference to the accompanying drawings. Like numbers refer to
like elements throughout.
Referring now to the drawings in greater detail, FIG. 1 shows the
single component polyurethane formulation of the present invention
contained within container 10, toggle valve-type trigger 12 is
fixedly attached to container 10. Trigger 12 comprises flanges 14,
16 which allows finger pressure to actuate the trigger mechanism.
The finger pressure causes the toggle valve (not pictured) to open
and release the pressurized polyurethane foam. The foam exits the
container and proceeds through the dispenser 12, through the
extender straw 20, and finally exits from the tip 22 of extender 20
as an expanding foam 24. The foam is shown directed into the
fenestration rough opening gap 30 between window frame 32 and wall
34. FIG. 2 shows an enlarged view of one type of trigger/straw
assembly that is used with a toggle valve.
FIG. 3 shows the single component polyurethane formulation of the
present invention contained within container 10 attached to a
gun-type dispenser 40 of the type that is the subject of U.S. Pat.
No. 5,615,804. Pressure exerted by the operator's trigger finger
(not shown) dislodges an internal mechanism from a rest position
and allows the polyurethane composition to release from the
container 10, through a channel (not shown) in dispenser 40,
through the dispenser shaft 42, finally exiting the tip 44 as an
expanding foam 24. The foam is shown directed into the fenestration
rough opening gap 30 between window frame 32 and wall 34.
FIG. 4 shows the single component polyurethane formulation of the
present invention contained within container 10 attached to a
gun-type dispenser 50 of the type that is the subject of U.S. Pat.
Nos. 5,549,228 and 5,887,756. Pressure exerted by the operator's
trigger finger (shown as being the thumb) 52 dislodges an internal
mechanism (not shown) from a rest position and allows the
polyurethane composition to release from the container 10, through
a channel (not shown) in dispenser 50, through the dispenser shaft
54, finally exiting the tip 56 as an expanding foam 24. The foam is
shown directed into the fenestration rough opening gap 30 between
window frame 32 and wall 34. FIG. 5 shows a cut away view of the
expanding foam 24 being directed into rough opening gap 30. It is
this rough opening gap 30 that must be filled during home
construction with a sealant to keep air from passing through the
assembly leading to drafts and a loss of energy in the form of
heating and cooling. The polyurethane foam of the present invention
is applied within this gap.
While the foams of the present invention find immediate and
important utility, and in fact were developed with the building
construction industry in mind, these foams display properties for
the first time in a single component polyurethane open-celled foam
of this type, and therefore find utility beyond the construction
industry. For example, the foams of the present invention may be
used wherever vibration or sound damping are desired, such as in
the automotive industry (roof, door, engine compartment panels,
etc.) or in the acoustic industry (for example, acoustic tiles and
ceilings or walls, etc.). Indeed, the foams of the present
invention may be used in the transportation industry to soundproof
passenger or engine compartments of transportation craft, for
example, of trains, cars, buses, planes, ships, etc. Further, the
excellent air barrier characteristics coupled with the foams
hydrophobicity, makes the foams excellent candidates to be used
wherever insulation is required in a moist or wet environment (for
example, appliances, wherever condensation or exposure to
environmental moisture could occur, marine engine and boat
manufacturing industries, etc.). The lack of attending foaming
force in light of excellent expandability also makes the foams
useful as insulation in the electronics industry. For the purposes
of this application, the term electrical devices encompasses
mechanical devices that, strictly speaking may not require
electricity to run. Still further, the foams would be useful as
resilient joints in the building industry with the foams interposed
between joints in wood, metal, stone facings, concrete or mixtures
thereof and expansion joints contained in these materials. Since
the foam of the present invention has a greater resilience as
compared with conventional moisture-cured single component foam
sealants, the present foam exhibits a greater ability to expand and
contract during joint movement without fracture or loss of
adhesion. Thus, the foams of the present invention made by the
compositions of the present invention tolerate greater flexing and
movement due to forces such as, for example, wind load cycling.
Recent testing has demonstrated that certain window perimeter
joints had to be redesigned due to this type of failure when a
conventional foam sealant was used.
The following examples serve to give specific illustrations of the
present invention, but are not intended in any way to limit the
scope of this invention. All percentages are given by weight unless
otherwise noted.
EXAMPLE 1
A vessel was charged with a premix comprising 15.9 percent hydroxy
terminated poly(oxyalkylene) polyol (1000 MW triol), 63.5 percent
hydroxy terminated poly (oxyalkylene) polyol (8000 MW diol), 1.4
percent 2,2'-dimorpholinodiethylether (DMDEE) (amine catalyst), 15
percent tri(1-methyl-2-chloroethyl) phosphate (PCF) (fire
retardant), 4.0 percent polyalkyleneoxidemethaylsiloxane copolymer
(silicone surfactant), and 0.23 percent colorant. The premix was
provided in an amount of 49.6 percent to an aerosol can along with
37.2 percent polymethylene polyphenyl isocyanate (PMDI). A glass
agitation ball was placed into the mixture in the can. An aerosol
type valve was crimped onto the can. Isobutane/propane/dimethyl
ether (IPDE) hydrocarbon blowing agent in an amount of 13.2 percent
was charged to the can through the valve. The can was then
thoroughly shaken and set into a box.
The polyurethane prepolymer prepared as described above had the
following weight percentages:
TABLE-US-00001 Formulation A Percent Component 37.8 PMDI (Dow
Chemical) 7.8 1000 mw triol polyol 31.3 8000 mw diol polyol 0.69
DMDEE (Huntsman) 7.4 PCF (Akzo Nobel) 0.12 Colorant 2.2 Silicone
surfactant (L-5340, Witco) 12.69 Isobutane/Propane/DME
The observed vinyl window frame deformation was approximately 0.04
cm ( 1/64 or 0.016 inch) for foam dispensed from the gun dispenser
without the straw extension tip, approximately 0.08 cm ( 1/32 or
0.031 inch) for foam dispensed using the gun dispenser with the
straw tip extender and approximately 0.05 cm (0.02 inch) for foam
dispensed through a trigger/straw dispenser. (This test is
explained in Example 3). The open cell content was about 88 percent
for foam dispensed through a plastic dispensing gun without the
straw tip extension, about 90 percent for foam dispensed through
plastic dispensing gun with the straw tip, and about 72 percent
open cells for foam dispensed through a trigger/straw dispenser.
Finally the amount of air passing through the foam was determined
to be about 0.01 L/s (0.02 cfm), for foam dispensed from the gun
dispenser with or without the straw extension tip or from a
trigger/straw dispenser using the method that is the subject of
Example 2.
By comparison, the observed vinyl window frame deformation for a
conventional one component foam (OCF) sealant, (Comparative 1)
dispensed through a plastic dispensing gun without a straw
extension tip was approximately 0.4 cm (0.16 inches) and
approximately 0.54 cm (0.21 inch) using the plastic gun dispenser
with a straw tip extension. The open cell content was about 23
percent without the straw tip and 14 percent with the straw tip.
The amount of air passing through the foam was determined to be
about 0.01 L/s (0.03 cfm). Other conventional OCF sealant,
comparatives 2 and 3, dispensed through a trigger/straw applicator
had an observed vinyl window frame deformation of approximately
0.59 cm (0.23 inch). The open cell content was about 15 percent.
The amount of air passing through the foam was determined to be
about 0.01 L/s (0.02 cfm). Table 1 below lists the tabulated
characteristics of various formulations listed as comparative
examples.
TABLE-US-00002 TABLE 1 Max. Deflection Percent Air Flow Formulation
Cm (inches) Open Cell L/s (cfm) **Formulation A 0.04 (0.02) 88
percent 0.01 (0.02) through plastic gun w/o straw tip **Formulation
A 0.08 (0.03) 90 percent 0.01 (0.01) through plastic gun w/straw
tip *Form. 1 through 0.05 (0.02) 72 percent 0.01 (0.02)
trigger/straw **OCF gun foam 0.40 (0.16) 23 percent 0.01 (0.03)
through plastic gun without straw tip (comparative 1) **OCF gun
foam 0.54 (0.21) 14 percent 0.01 (0.03) through plastic gun with
straw tip (comparative 1) *OCF straw foam, 0.58 13 percent 0.01
(0.02) comparative 2 *OCF straw foam, 0.61 31 percent 0.01 (0.03)
comparative 3 Note: *= 72'' .times. 36'' vinyl replacement window
**= 72'' .times. 21'' vinyl new construction window
EXAMPLE 2
Determination of Rate of Air Leak
This test consisted of sealing a test sample into or against one
face of an air chamber, supplying air to or exhausting air from the
chamber at the rate required to maintain the specified test
pressure across the sample, and then measuring the resultant
airflow through the specimen. Test jigs were cut into dimensions of
39''.times.3.5'' with a 0.5'' gap in between two pieces of wood.
The test jigs were bonded together to produce a wood frame and
provide a positive seal against the air barrier apparatus. The
samples were prepared by placing an extender on a dispenser that is
positioned to a point approximately halfway into the gap formed by
the wood frame. The polyurethane foam was dispensed under pressure
in a long, steady 36'' continuous bead. The polyurethane foam bead
prepared in the wood frame was dispensed in one to two passes. The
filled wooden frame with the foam sample contained therein was set
into the test chamber. The sample foam was tested in an untrimmed
state. A controllable blower designed to provide the required
airflow at the specified test pressure differences was provided.
The differential test pressures were determined by an on-line
manometer, and an airflow metering system measured the airflow into
the test chamber, and through the sample. The sample was
conditioned and allowed to cure at 73.degree. F.+/3.degree. F. and
50 percent +/5 percent relative humidity for 24 hours prior to
testing. The smooth face (side) of the sample was placed against
the chamber opening. The sample jig was clamped down to secure the
sample in place. The air flow meter was opened to the lowest range
and the pressure was dialed down to 75 Pa on the manometer. Once
the test conditions stabilized, the airflow through the sample was
recorded in terms of cubic feet per minute (cfm). The tested
samples of the present invention recorded air leak values of from
0.01 to 0.10 cfm at room temperature. The airflow was calculated
directly from the meter, and yielded the results shown in Table 2.
Values for convention OCF's as well as a conventional latex foam
sealant and a fiberglass chinking sealant are given by way of
comparison.
TABLE-US-00003 TABLE 2 Formulation Air Permeability L/s (cfm)
Formulation A through plastic gun w/no tip 0.01 (0.02) Formulation
A through trigger/straw 0.01 (0.02) OCF Gun through plastic gun
w/no tip 0.01 (0.03) (comparative 1) OCF straw foam sealant
(comparative 2) 0.01 (0.2) Latex foam sealant (comparative) 0.37
(0.78) Fiberglass chinking, med. fill (comparative) 0.8 (1.7)
Fiberglass chinking, dense fill (comparative) 0.35 (0.74)
EXAMPLE 3
Method of Determining Deflection of Window Frame Along
Perimeter
This test consisted of measuring the extent of window frame
deflection by measuring the force required to open the window. A
structure (buck) was created to support the window and simulate the
rough opening. The window was then installed per manufacturer
instructions. The buck was marked at three levels of the window.
The buck width was measured at three levels for initial outer buck
width values. At the same mark, but within the window jamb, the
distance between the inner window jambs is marked and measured to
the nearest 0.158 cm ( 1/16''). To measure the bottom distance, the
window was opened to a set height and the distance was measured. A
total of six (6) rough opening gap measurements were made (three
each on the two longest sides of the window) at the three
established levels. The three levels are set at one-third,
one-half, and two-thirds the length of the longest window side.
Measurements were made to 0.01'' (0.0254 cm); three along the right
side and three along the left. With the window sash in the down
(closed) position, five (5) force measurements were made by pulling
the window up to determine "breaking force" and the range of low
and high "operating force". With the window up, the sash was pushed
down five times with the breaking and operating forces recorded
before and after the other test measurements to insure the buck is
dimensionally stable throughout the test. Prior to foaming the
window, the product, lab book or batch, dispenser type, product,
temperature and relative humidity are recorded. The foam was
dispensed in the following manner: up the left side and across the
top, across the bottom and up the right side. After 24 hours, the
buck width, inner window jamb, and operating force, both up and
down, are re-measured to determine the deflection and operating
force caused by the foam. The percent difference from "initial" and
"final" values were determined. Note: differences greater than
0.1587 cm (0.0625''), and force measurements greater than 133N (30
lbf) represent values considered to be minimum values above which
determine failure. See Table 3.
TABLE-US-00004 TABLE 3 Formulation Max. Deflection Max. Operating
Force and dispenser Cm(inch) Before/After Foaming *Formulation A
through 0.01 cm (0.04'') 89N (20 lbf) 89N (20 lbf) plastic gun
*Formulation A through 0.05 cm (0.02'') 85N (19 lbf)/85N (19 lbf)
trigger/straw *OCF Straw foam 0.58 cm (0.23'') 75N (17 lbf)/156N
(35 lbf) sealant (comparative 2) *OCF Straw foam 0.61 cm (0.24'')
75N (17 lbf)/182N (41 lbf) sealant (comparative 3) Note: *= 72''
.times. 36'' vinyl replacement window **= 72'' .times. 21'' vinyl
new construction window
EXAMPLE 4
A vessel was charged with a premix comprising 16 7 percent hydroxy
terminated poly(oxyalkylene) polyol (1000 MW triol; 30-168 from
Arch), 66.9 percent hydroxy terminated poly(oxyalkylene) polyol
(9300 MW triol; from Arch), 1.2 percent
2,2'-dimorpholinodiethylether (DMDEE) (amine catalyst from
Huntsman), 13.0 percent tri(1-methyl-2-chloroethyl) phosphate (PCF)
(fire retardant from Akzo Nobel)), 2.0 percent silicone surfactant
(L-5340 from Witco), and 0.2 percent colorant from Millikin.
The premix was provided in an amount of 48.2 percent by wt. (of the
final formulation) to an aerosol can along with 38.6 percent
polymethylene polyphenyl isocyanate (PMDI). A glass agitation ball
was placed into the mixture in the can. An aerosol type valve was
crimped onto the can. Isobutane/propane/dimethyl ether (IPDE)
hydrocarbon blowing agent in an amount of 13.2 percent by wt. was
charged to the can through the valve. The can was then thoroughly
shaken and set into a box.
The open cell content was about 83 percent for foam dispensed
through a trigger/straw applicator.
Many modifications and other embodiments of the invention will come
to mind to one skilled in the art to which this invention pertains
having the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the invention is not to be limited to the specific
embodiments disclosed and that modifications and other embodiments
are intended to be included within the scope of the appended
claims. Although specific terms are employed herein, they are used
in a generic and descriptive sense only and not for purposes of
limitation.
* * * * *