Note: Descriptions are shown in the official language in which they were submitted.
~0 40/11309 Pcr/~lsso/ol477
~0~767~
--1--
LINEAR POLYIJRETHANE ELAST02~1ER COMPOSITIONS AND
USE OF MODIFIED DIISOCYANATES FOR PREPARING SAME
Technical Field
The present invention relates to the preparation of
linear ~hermoplastic polyurethane elastomers of a polyol
component, at least one extenlder component, and a
diisocyanate compound by initially reartiny the diisocyanate
compound with the extendex to form a modified diisocyanate
component prior to reac~ing this component with ~he polyol
component and other extenders, if any.
Backqround Art
In today's market, polyurethane elastomers are utilized
in a wide array of products and applications, including
producing industrial coated fabrics. For the latter, these
polyurethanes are generally linear polymers exhibiting
elastomeric characteristics of high tensile strength and
elongation.
These linear polyurethanes are quite varied in their
final properties as a result of the large number of
permutations that can be applied to the three main
components that are used in their manufacture. These
components are polyols, polyisocyanates, and one or more
extenders (generally diols). Some examples of these
compounds are: polyether, polyester, polycaprolactone,
polycarbonate, and polybutadiene polyols; toluene
diisocyanate, 4,4'-diphenylmethane diisocyanate, cyclohexane
diisocyanate, isophorone diisocyanate, naphthalene
diisocyanate: xylene diisocyanate, hexane diisocyanate, and
hydrogenated 4,4'-diphenylmethane diisocyanate; and 1,4-
butanediol, 1,6-hexanediol~ and 1,3-butanediol extenders.
Typically, polyurethane elastomers which are considered
top of the line with respect to performance, include, for
example, polytetramethylene glycol (polyether) polyurethanes
and poly(butane adipates or hexane adipates) ester
w090/ll309 2 ~ ~ 7 6 7 ~ PCT~usgo/ol~7
polyurethanes. of these polymer~, the polyether
polyurethanes exhibit good hydrolytic stability and low
temperature properties but are generally poor for fuel
resistance and oxidation resistance, while the polyester
polyurethanes are tough with good abrasion resistance,
oxidation resistance ~nd fuel resistance, but not
particularly resistant to hydrolysis. Still, at the present
time the polyesters are generally considered to represent
the best compromise of physical properties and chemical
resistance of the various polyurethanes.
There are also a few polyurethanes based on
polycarbonate polyols in the market. It is well known ~hat
these polycarbonate polyurethanes have very good hydrolytic
stability and generally have good to very good resistance to
other de~radation forces; however, th~y ars ùsually too
hard, rigid and brittle for use in industrial coated
fzbrics.
Currently, high performance coated fabrics are based on
polyester polyurethanes in order to meet the specifications
currently in effect, but resistance to hydrolysis remains
their weak point and represents a problem for these
products. Thus, there is a desire ~or improved hydrolytic
stability in a number of applications. A polyurethane
having improved hydrolytic properties and sufficient
elastomeric character to be useful in the manufacturing of
industrial coated fabrics is also desirable and needed.
It is known from Japanesa Patent Specification
Sho(61)-76275 that polyurethane elastomers can be produced
from a diol mixture of a polycarbonate diol and a
polyoxytetramethylene glycol, and/or a polydimethyl siloxane
glycol: an organic diisocyanate and a chain extension
compound. Practical Example 4 of Table I lists a porous
polyurethane fil~ formed from an 80/20 mixture of
polycarbon~te diol and polyoxytetra methylene glycol; 4,4'-
diphenyl methane diisocyanate and 1,4-butylene glycol, while
Practical Example 1 illustrates a film formed from a
WO ~/11309 2 0 ~ 4~ 6 7 8 Pcr/~s~/ol4~7
--3--
50/25/25 mixture of polycarbonate diol/polyoxytetra
methylene glycol/polydimethylsiloxane glycol; 4,4'-diphenyl
methane diisocyanate and ethylene glycol. ~hes~ porous
films can be used in the manufacture of arti~ioial leather
or suede articles.
Also, Japanese Patent Specification Sho(61)-151235
discloses the preparation of aliphatic polycar~onate polyols
from various mixtures of dialkyl carbonates and glycols.
These polyols are described as ha~ing low color adhesion and
smooth reactivity with isocyanates. Neither reference
suggests that these ~aterials can be used as or in the
production of polyurethane elastomers for industrial coated
fabrics.
A wide variety of organic isocyanate and polyisocyanate
compounds are available for use in the preparation of
polyurethane elastomers. The particular isocyanate is
selected to facilitate preparation of the polyurethane for
the intended application. Generally, isocyanates which are
liquid at room temperature are prepared for ease of
handling.
Diphenyl methane diisocyanate ("MDI") is a solid
diisocyanate which is available on a commercial scale and
consists primarily of the 4,4' isomer with a small amount of
the 2,4' isomer. These isomers are both solids at room
temperature, having melting points of 42 and 36 C,
respectively. Other isomers, such as the 2,2' isomer, are
also solid at room temperature.
~ o convert solid MDI into a form which is more
desirable for use in thP preparation of polyurethanes, the
prior art teaches that a liquid MDI cs~position can be
prepared, for example, by partially reacting solid MDI with
a glycol, diol or other polyol. Generally, about 10 to 35%
of the isocyanate groups are reacted with the polyol. A
number of U.S. patents illustrate this concept, including
U.S. Patents 3,883,571, 4,115,429~ 4,118,411, 4,22g,347,
WO90/11309 2 0 ~ 7 6 7 8 PCT/l~S~/01477
4,490,300, 4,490,301, 4,539,156, 4,539,157 and 4,539,158.
Such liquid diisocyanates are stated as beiny useful for
forming polyurethanes for a wide variety of applications.
None of these modified diisocy~nate compositions have,
however, been utilized to prepare linear thermopla~tic
polyurethane elas~omPr~ whic~h have lower temperature
processing characteristics clD~pared to similar compositions
prepared from solid MDI.
Summary o~ the Invantion
The invention relates t~ improvements in the
preparation of a linear the~moplastic polyurethane elastomer
composition prepared from a polyol component, a diisocyanate
compound, and first and second extender components. The
processing temperature of the polyurethane is lowered by
initially reacting the diisocyanate compound with the ~irst
extender in a molar ratio of above 2:1 to form a modified
diisocyanate component having a functionality of about 2
prior to reacting the modified diisocyanate component with
the polyol and second sxtender components. Thus, a linear
thermoplastic polyurethane elastomer composition is formed
which has lower temperature processing characteristics
compared to similar compositions wherein the diisocyanate
compound is not modified.
The pslyol component may be a polyether polyol,
polycarbonate polyol, polycaprolactone polyol, polyester
polyol, polybutadiene polyol or mixturas thereof, and the
first extender component is generally a polyol or amine
compound having a molecular weight of less than about 500.
Preferably the first extender component comprises a diol.
Also, the second extender component is included for optimum
results.
Generally, between about 10 to 30% by weight of the
diisocyanate compound is modified so that the modified
diisocyanate component has an NCO content of between about
w~ ~/ll~9 2 0 ~ 7 6 7 8 PCT~S90~01477
14 and 33%, and preferably between about 20 and 26~. The
most advantageous diisocyanate compound is one that
primarily oomprises 4,4'-diphenyl methane diisocyanate, with
the first extender component being ~ polyol or amine
compound having a molecular weight between about 60 and 250,
6uch a~ 1,4-butane dlol, tripropylene glycol, dipropylene
glycol, propylene glycol, ethylen~ glycol, 1,6-hexane diol,
1,3-butane diol, neopentyl glycol, ethylene diamine or
mixtures thereoP.
The present invention also relates to a l$near
thermoplastic polyurethane elastomer compositions comprising
a mixture of a polycarbonate polyol and a polyether polyol;
a diisocyanate compound; and first and second extenders.
The diisocyanate compound is initially reacted with one of
the extenders in a molar ratio of above 2:1 60 as to form a
modified diisocyanate component having a functionality of
about 2 prior to reaction with the other components. This
modified diisocyanate component provides relatively low
tamperature processing properties to the composition,
whereas the polyol mixture provides superior hydrolytic
stability and low temperature flexibility to the
composition.
Preferably, the first extender component is a polyol or
amine compound having a molecular weight of lass than about
500, such as a diol, while the diisocyanate compound
primarily comprises 4,4'-diphenyl methane diisocyanate.
Advantageously, the first ex~ender component is a polyol or
amine compound having a molecular weight between about 60
and 250, such as 1,4-butane diol, tripropylene glycol,
dipropylene glycol, propylene glycol, ethylenQ glycol, 1,6-
hexane diol, 1,3-butane diol, neopentyl glycol, ethylene
dia~ine or mixtures thereof.
Generally, the polyether polyol and polycarbonate
polyol are present in a relative amount of between 2:1 to
1:8. When the first extender is 1,4-butanediol and the
WO ~/ll309 2 ~ ~ 7 ~ PCT/~S~/~1477
--6--
second extender i5 tripropylene glycol, and when between
about lo to 30% by weight o~ the dii.~ocyanate compound is
modified~ the modified diisocyanate compo~ent has an NCo
content of between about 14 and 33~, preferably between
about 20 and 26~. A~ter ~odifying the dii~ocyanate, the
modified ~at~ri~l is reacted with the o~her compon~nts. The
overall NCO/OH ratio of th~ entire composi~ion is between
about 0.95 and 1.05/l.
Detailed Description _~ the_I~vention
One preferred embodiment of this invention relates to a
polyurethane elastomer based on a mixture of polycarbonate
and polyether polyols, a modified diisocyanate component
formed by reacting a diisocyanate compound with a low
molecular waight extender such as tripropylene glycol, and a
second extender of 1,4-butanediol. The modified
diisocyanate and the second extender ena~le the polymer to
have low temperature processing properties compared to those
wherein the diisocyanate is not modified. This polymer also
has hydrolytic stability which is vastly superior to
conventional polyester polyurethanes. This polymer also has
elastomeric characteristics and other physical properties
which render it suitable for use in coated fabric
manufacturing processes and resultant products produced
therefrom.
In this embodiment, the polyether polyol and
polycarbonate polyol can be used in any relative amounts
provided that each are present in the co~position. It has
been found convenient to use a polyether polyol:
polycarbonate polyol ratio in the range o~ between 2.1 to
1:8.
Instead of tripropylene glycol and 1,4-butanediol,
other low molecular weight extender~ ca~ be used.
Generally, polyols having a ~olecular weight o~ between
about 60 and 500 (and preferably less than 250) have been
WO ~/1l~n PCT/US~J01477
2~767~
--7--
found to be advantageous, although amines ~uch as ethylene
diamine can also be used. Specific polyols include diols
such as 1,3-butanediol, ethylene glycol, tripropylene
glycol, dipropylene glycoI, propylene glycol, and neopentyl
glycol, triols ~uch as trimethyol propane, as well as
mixtures of these component~, can ~ u~ed.
Any dii~ocyanate co~pouncl i8 ~uitable with those based
on 4,4'-diphenyl methane diisocyanate being preferred.
Toulene diisocyanate, naphthalene diisocyanate, isophorone
diisocyanate, xylene diisocyanate and cyclohexane
diisocyanate can also be used, if desirsd, but these
compounds are generally more expensive or slower reacting.
Such diisocyanate compounds are converted to a modified
diisocyanate component as previously described.
The relative amount of modified diisocyanate to polyol
ranges from above 2:1 to 20:1, and preferably between about
2.5:1 and 8:1. The second extender compound is included in
an amount to achieve a final NCO:OH ratio of between about
0.95 to 1.05/1. The Examples illustrate preferred ratios of
componen~s for use in the preparation of linear
polyurethanes in accordance with this invention.
Another preferred embodiment of the invention relates
to the manufacture of any type of polyurethane elastomer
prepared from the modified diisocyanate component to
significantly lower the temperature re~uirements for
processing the polyurethane on heat processing equipment,
i.e., calenders, extruders, injection molding apparatus,
etc. This modification includes reacting diisocyanate
compound with 2 low molecular weight extender (i.e., polyol
or amine compound, to form a ~odi~ied diisocyanate
component, prior to preparing the polyurethane with the
other components.
The term "MDI" will be used throughout this application
to designate diisocyanate compounds primarily based on
4,4'-diphenyl methane diisocyanate which are preferred for
use in this invention. Also, the term "liquid MDI" will be
.
.,
WO90/11309 2 0 4 7 6 7 ~ P~T/US~/01~77
used to designate an e~sentially difunctional m~dified MDI
component prepared ~rom tha reaction of a low ~olecular
weight polyol with an ~DI compound to ~orm a modified
diisocyanate composition which i5 liquid at room
temperature.
The low molecular weight extender used to ~odi~y the
diisocyanate compound generally includes diols, triols or
amines having 2 mol~cular w~ight b~low about 500, but any
polyol which enables the diiEocyanate compound to possess a
functionality of about 2 and an NC0 content of between about
14 and 33%, preferably between 20 and 26S, after
modi~ication, would be acceptable.
In this e~bodiment, Pssentially any polyol component
can be used for reaction with the liquid MDI component,
including polyether, polyester, polycaprolactone,
polycarbonate or polybutadiane polyols or mixtures thereof.
As noted above, a preferred polyol component is mixture of a
polyether polyol and ~olycarbonate polyol.
It is also possible to add additional extenders to such
compositions, these extenders also beins a polyol or amine
compound, preferably one of relatively low molecular weight
(i.e., less than about 500). It is also possible to utilize
unsaturated polyols as extenders, such as low molecular
weight diols which include one or more double bonds.
However, any conventional ~xtender known to those skilled in
the art can be used, depending upon the results desired.
Thus, the present invention demonstrates how various
polycarbonate and polyether polyols, modified diisocyanate
components and extenders may be blended over a wide range to
allow the design of polyurethane poly~ers having different
physical characteristics and properties. This ma~es it
possible to custom design a polymer for a particular
application.
There are several different types of modified ~DIs
presently on the market, but the types suitable for use in
this invent:ion are essentially difunctional. The preferred
WO ~/ll309 PCT/~'S~/0147,
~7~i78
g
liquid MDI components are made by rea~ting an MDI compound
with a small amount of a diol such as tripropylene glycol or
a mixture of diols. The material resulting from this slight
extension of the MDI compound is a liguid at room
temperature while, as noted above, the original MDI compound
is a solid at ~uch te~peratures. Thi~ makss the liquid MDI
substantially easier to handle and process, while retaining
generally equivalent performallce to the unmodified M~I
compound.
Representative modified liquid MDI components which are
suitable and preferred or use in ~he present invention are
disclosed in U.S. Patents 3,883,571, ~,115,429, 4,118,411,
4,229,347, 4,490,300, 4,490,301, 4,539,156, 4,539,157, and
4,539,158: all these components are essentially
difunctional and are obtained as the reaction product of
MDI. With a diol or polyol having a molecular weight below
about 500. To the extent necessary to understand this
component of the inventive compositions, these patents are
expressly incorporated herein by reference thereto. Those
isocya~ates having a functionality which is much greater
than two are not particularly suitable for use in this
invention, since they promote crosslinking rather than
linearity in the resultant polyurethane polymer. The
functionality of these compounds should be above 1.9 but
below 2.2, with the preferred modified diisocyanate
components being those having a ~unctionally of
approximately 2 so as to ~acilitate the preparation of
linear polyurethanes.
In the production of polyurethanes, it is generally
known to utilize one of two different manufacturing
processes. In one ~ethod, known as the i'one-shot" approach,
all hydroxyl bearing components (i.e., polyols and extender
diols) are combined as a mixture, to which is added an
isocyanate component in essentially stoichiometric
quantities to form the final product. The second method
contemplates the formation of a prepolymer by reacting
WO90/11309 2 ~ 4 ~ ~ ~ 8 PCT/US~/01477
--10--
excess isocyanate with one or more high molecul~r wei~ht
hydroxyl bearing components, followed by th~ reaction of
this prepolymer with the extender to form he final product.
As noted abova, the use of th~ modified diisocyanate
components of this inventiDn enables a polyur~than~ having
lower temperature proce~sing characteristics to be achieved.
The temperature difference can be as great ~s 30 to 40F
below that of a correspondin~ formulation wherein the
diisocyanata compound is not modified. However, greater
temperature reductions are achieved when the polyurethane is
manufactured in a specific manner.
For example, if the polyurethanes o the invention are
made by the conventional "one shot" technique, a slight
reductio~ on the order of about 3-4 degrees is obtained:
this representing only about 10% of the maximum reduction
which could be achieved. Similarly, if solid MDI is used to
prepare an isocyanate prepolymer with the high ~olecular
weiyht polyol prior to reacting this prepolymer with the
mixed extenders, a temperature reduction of about 4-5
degrees (i.e., about 15% of the maximum) is achieved.
Substantial reductions in the temperature
processability of the resulting polyurethane can be achieved
by following one of the following methods Qf manufacture.
In one version, the isocyanate is pre~reacted with one of
the extenders to form a ~odified isocyanat~ component prior
to reaction with a mixture of the high molecular weight
polyol and other extenders. This enables a temperature
reduction of about 20 to 25 degrees to be achieved (i.e.,
about 60% of the optimum~. Finally, tha optimum temperature
reduction is achieved by sequentially reacting the modified
isocyanate compon~nt first with ths hi~h ~olecular wei~ht
polyol followed by reaction with th~ second extender. As
noted above, ~ temperature reduction o~ 30 to 40 degrees is
possible, with the formation of a clear polyurethane
polymer.
WO go~1 t309 P~T/l,IS90/01'177
~7678
Again, MDI, modified as di5clo~ed herein, is the most
advantageous diisocyanate for US2 in preparing the
polyurethanes of this invention, although the othar
isocyanates mentioned above c:an instead b~ used, if desired.
When light stability in a cl~!ar product i~ desirsd, an
isophorone diisocyanate can be used to achieve better
results than MDI. For a lower co~t isocyanate component,
toluene diisocyanat~ (nTDIn) can be used, but it i8 less
re~ctive than MDI. Thu~, when TDI i8 u~ed, ~ine extenders,
rather than polyol or di~l extenders, 6hould bæ used. One
skilled in the art can select the best co~bination of
ingredients for any particular formulation.
These linear polyureth~ne elastomers are preferably
made using a two step solution polymerization techniqueO
Predried toluene, dimethyl formamide and the isocyanate are
charged to a 3000 ml reactor (in some cases a 15,000 ml
reactor was u-~ed). A given weight of polyol(s), the amount
needed to achieve the desired prepolymer NCO/OH value, is
dissolved in additional dry toluene. The reactor is then
prepurged with dry nitrogen and maintained under a posi~ive
low pressure of dry nitrogen for the ~ull reaction time.
The isocyanate containing solution is preheated to 65-
75DC (depending on anticipated exotherm~, and the solution
of polyols is slowly added by a continuous stream (over
one-half hour) to the reactor. The temperature is allowed
to rise to 80-~O~C (depending on system) and is maintained
at this temperature for an additional two hours.
The desired extender diol is preweighed and dissolved
in dry dimethyl formamide. The rea¢tor is coolad to 60-65C
and two 7-lO gram samples of ~he reac~ion ~ixture are
removed and analyzed ~or NCO conte~t. The diDl is then
charged to the reactor, and the te~perature raised (partly
by the exotherm of extension) to 85-90-C and maintained at
this temperature ~or two hours. A sample o~ the polymer is
dried and an IR spectrum was run. If free NCO is detected
in the spectrum, the reaction is continued for another hour.
wo ~J11309 2 ~ ~ ~ 6 7 ~ P~T/US90/01~7~
-12-
~ e reaction solution is then allowed to cool to room
tempera~ure overnight and stored in a container until it can
be tested. All mixtures were designed to yield a solution
of 30S by weight of polymer dissolved in a 60/40 mixture of
toluene~DMF.
This solution cooking te~chnique provides an easy way of
making this polymer, but it is difficult to evaluate the
physical properties of such ~,olutions. Thus, the solution
collected from an individual cook is ~pread coated onto
rele~se paper and dried at 300~F to remove the solvent.
This film c~n then be strippe!d from the paper and used to
conduct various physical property tests.
A. Modulus, Tensile Strenqth, and Elongation
One gram of cadmium stearate was added to 200 grams of
dried polymer and intimately mixad on a two roll rubber
mill. A 0.040 inch slab of polymer was removed from tha
mill and was u~ed to make tensile specimens. This was done
by pressing the slab between two polished plates in a heated
Wabash press for 15 minutes at sufficient temperature and
pressure to yield a 0.010 - 0.014 inch film. Temperatures
and pr~ssures varied depending upon the particular
formulation. The press was cooled to roo~ temperature and
the film was removad ~rom between the plates. From this
film, five samples wer~ cut in the size of one inch by six
inches. These were then tested on an Instron and averages
sf 100% modulus, 200% moduius, tensile strength, and
elongation were calculated from the test results. The
temperature for the milling and pressing operations were
observed and found to be related to formulation ch~nges.
B. Toluene Swell
~ wo pieces, one inch by two inches, of the pressed film
wera immersed in toluene for 24 hours. Measure~ents of
volume by displacement of alcohol before and after toluene
immersion were used to calculate volume swell.
WO ~11~9 2 ~ ~ 7 ~ 7 8 PCT/~'~90/~l477
-13-
C. Flow TemPerature and Flow Rate
A three to five gram sample of polymer wa~ finely
chopped and used to determine the ~emperature at which the
polymer would flow at a measurable rate and to determine the
rate itself on a Kayness, Inc. extrusion plastometer ~odel
D-0051. A measurable rate wa~ defined a greater than 0.15
grams per 10 ~inutes. Thu3 at t2mperatures below ~he flow
temperature, neither fusion of the polymer nor flow greater
than 0.15 grams i5 achieved. The ~low rate i5 defined as
the number of grams extruded from the barrel of the
plastometer in a period of ten minutes.
D. Brookfield Viscosity
Fifteen grams of polymer were dissolved in 85 grams of
dry dimethyl formamide and warmed to 30 d~grees C~ntigrade
in a constant temperature bath overnight in a closed
waterproof container. The viscosity was then measured on a
Brookfield viscometer as quickly as possible after removing
from the bath. Viscosity data is reported in cps.
E. Glass Transition Temperature (Tq)
Several polymer slabs, including a known control, were
measured for Tg. This work was done by two techniques,
mechanical spectroscopy which measures the change in
physical properties due to passing through the glass
transition temperature and DSC (differential scanning
calorimetry) which measures the second order transition
defined as glass transition te~perature.
The improvements and advantages associated with the
lin~ar polyurethane polymers developed in this invention are
illustrated below in the Examples.
Examples
The scope o~ the invention is further described in
connection with the ~ollowing examples which are set forth
for the sole purpose of illustrating the preferred
W090/ll309 2 0 ~ 7 ~; 7 ~ PCT/US~/01~77
-14-
smbodiments of the invention and which are not to be
construed as limiting the scope of the invention in any
manner. In these examples, all parts given are by weight
unless otherwise specified.
The specific preferred chemicals utilized in the examples
are listed below as follows:
W090/11309 ~ 7 ~ PCTI~SgO/Ot477
-15-
POLYOLS
0ll Equiv,
Supplier Identity TYpe Nu~ber Wt.
~G Industries Duracarb 120aliphatic carbonate 131.0 423.
PPG Industries Duracarb 122alipl~atic carbonate 95.0 590.0
PPG Industries Duracarb 124aliphatic carbonate 58.0 967.2
QC Chemicals Polymeg 1000 PTMEG ether 111.9 50103
QC Chemicals Polymeg 2000 P1'MEG ether 55.7 1007.2
Whitco Chemical Form-re~ 44-112 ester 113.3 495.1
ISOCY~NATES
Equiv.
Supplier Identity Type % NCO Wt.
.
ICI Rubinate 4~ MDI 33.5 125.0
ICI Rubinate LF-179 liquid MDI 23.0 1~2.5
Mobay Corp. Mondur PF liquid MDI 22.9 183.4
B~SF Lupranate MP-102 liquid MDI 23.0 182.5
Dow Chemical Isonate 181 liquid MDI 23.0 182.5
EXTE~DER DIOLS
Supplier Identity Equivalent Weiqht
B~SF 1,4-butanediol 45
Dow Chemical tripropylene glycol 96
.
WO90/11309 2 0 4 7 6 7 8 PCT/US~/01~77
-16-
Examples l-l2
Table I (A&B) illustrates the erfect that modified
liquid MDI components have on flow ~emperature o~ various
polyurethanes compared to those made from the corresponding
unmodified MDI compound. The talble li~ts six polyurethanes
mada with various polyols, including ~ome mixtures of polyols.
Each two examples represent a polyurethane made from liquid MDI
and its analog made fro~ th~ corr~sponding MDI unmodified,
solid component. As shown in ~e table, the percent hard
segment is equivalent in each cc~mparison. Examples l, 3, 5, 7,
9 and ll are in accordance with the present invention, while
Examples 2, 4, 6, 8, lO and 12 are included for comparison. In
all cases, the liquid MDI polymer has a lower flow temperature
than its solid MDI analog. Flow temperature is that
temperature at which a measurable flow is first observed when
tested on an extrusion plastometer.
Since flow temperature is a measure of the
temperature at which the polymer may be processed on
calendering and extrusion equipment, the use of the liquid MDI
components allows the making of polymers which process at lower
temperatures, and therefore are easier to process and
manufacture into articles such as calendered sheets for coated
fabrics. The results demonstrate that all experimental
polymers made with liquid MDI components exhibited lower
milling temperatures than those of their solid MDI analogs.
Although Table I illustrates polyurethanes made with
polyether, polyester, and polycarbonate polyols, it would be
expected that this improvement would be present regardless of
the specific type o~ polyol used.
Examples 13-16
The section on chemicals lists four commercially
available liquid ~DI components and describes how they are
produced. Table II (A&B) demonstrates that these four
isocyanates are essentially equivalent in their ability to
~0 ~/ll309 2 0 4 7 6 7 8 PCT/~S~/01~77
~16-
Examplas 1-12
Table I (A&B) illustrates the effect that modified
liquid MDI components have on f]ow temperature of various
polyurethanes compared to those made from the corresponding
unmodified MDI compound. The table list~ six polyurethanes
made with variou~ polyols, including ~ome ~ixtures of polyols.
Each two examples represent a polyurethane made from liquid ~DI
and i~s analog made from the corresponding MDI unmodified,
solid componen~. As shown in ~l¢ table, the percent hard
segment is eguivalent in each comparison. Examples 1, 3, 5, 7,
9 and 11 are in accordance with the present invention, while
Examples 2, 4, 6, 8, 10 and 12 are included for co~parison. In
all cases, the liquid MDI polymer has a lower flow temperature
than its solid MDI analog. Flow temperature is that
temperature at which a measurable flow is first observed when
tested on an extrusion plastometer.
Since flow temp~rature is a measure of the
temperature at which the polymer may be processed on
calendering and extrusion equipment, the use of the liquid MDI
components allows the making of polymers which process at lower
temperatures, and therefore are easier to process and
manufacture into articles such as calendered sheets ~or coated
fabrics. ~he results demonstrate that all experimental
polymers made with liquid MDI components exhibited lower
milling temperatures than those of their solid MDI analogs.
Although Table I illustrates polyurethanes made with
polyether, polyester, and polycarbonate polyols, it would be
expected that this improve~ent would be present regardless of
the specific type of polyol used.
Examples 13-16
The section on chemicals lists four commercially
available liquid MDI components and describes how they are
produced. Table II (A~B) demonstrates that these four
isocyanates are essentially equivalent in their ability to
W~ gO/I 1309 2 0 ~ 7 ~i 7 ~ PCr/~S90~0147~
~odify the flow temperatures and therefore the p~oc~ssing
temperatures of polyurethanes made from them. Any one of these
four preferred isocyanates may be employed in the development
of low temperature processable ,polyurethanes~ As noted above,
a wide variety of difunctional i~ocyanates which are ~odified
by reaction with low molecular lweight polyols would ~lso be
suitable for use in this invention.
Examples 17-22
Table III (A&B~ compares ~polycarbonate polyurethanes made
from liquid MDI components against those made with solid MDI
components. Examples 17-19 are in accordance with the
invention, while Ex~mples 20-22 are comparative. It can be
seen from the data that polyurethane polymers made using liquid
MDI exhibit better physical properties, particularly tensile
strength, compared to those made with solid MDI. Flow
temperatures were not specifically measured on the liquid MDI
polymers, but processing on the mill was found to be
significantly better than for polymers made with the comparable
unmodified, solid MDI compounds.
It should al o be noted that the use of liguid MDI allows
the production of polyurethane elastomers having a higher
percent hard segment. This is advantageous because in general
the urethane linkages are much more stable to various
degradation forces (i.e. hydrolysis, oxidation, etc.) than are
ether, ester or other bonds in the polyol ~ackbone.
Examples 23-38
Polyurethane elastomers made from an aliphatic
polycarbonate polyol, liquid MDI and 1,4-butanediol were
prepared as shown in Table III, ~xamples 17-19. A mixture of
polycarbonate polyols was used in Example 38 of table IV.
Excellent physical properties, particularly tensile strength
and elongation, were achieved in these formulations. Upon
further analysis of the tensile curves, it was observed that
these polymers were more plastic than elastomeric in character.
wO ~/11309 2 0 ~ 7 ~ 7 ~ PCT/US~/01~77
-18-
Thus, these polymers could be described as hard and tough with
a high yield val~e as illustrated by the lO0~ modulus values.
However, evaluation of ~ilms of the polycarbonate based
polyurethane polymers exhibited poor cold crack properties.
To improve low temperature~ properties without sacrificing
the properti~s of the polycarbonate backbone, a copolyol was
introduced into the system, ~s ~hown in ~xa~ples 23-37 of
Tables IV (A & B). ~ polytetramethylene glycol ("PTMGI') polyol
was found to have ~h~ compatibility with the specific
polycarbonate polyols used, with the ~olecular weight of lO00
and 2000 each found to be suitable.
From Table IV (B), it i5 observed that physical
properties, i.e. modulus, elongation, tensile strength, and
toluene swell are affected by percent weight secondary and by
percent hard sPgment. Thus, as the percent of secondary polyol
(PTMG polyether~ is increased, (or the polycarbonate is
decreased), modulus decreases and the polymer becomes more
elastomeric than plaetic. Also as the percent hard segment
decreases, the modulus decreases but toluene swell (a measure
of solvent resistance) increases. From this information, one
skilled in the art can select the optimum combinations for the
desired final product.
Two different molecular weight polyethers were
evaluated. The results tend to indicate that change in
properties is mainly related to the percent (by weight) of
secondary polyol rather than to the molecular weight of the
PTMG polyol. It is also observed that there is some lowering
of tensile strength at higher percent secondary polyol, but at
a weight ratio of primary/secondary polyol of greater than or
equal to one, this is not significant. Increased ~olecular
weight of these polymers can also be used to counteract this
effect.
w~ 1309 2 0 ~ 7 6 ~ ~ PCT/~'S~/0147~
--19-
Examples 39 and 40
The ability to custom design a polymer to ~eet various
physical requirements is suggested by the results of Table V.
It is al~o possible to improve low temperature properties.
Table V (A&B) compares two ~ormulations which are similar with
the exception of the introduction of 20S PTMG polyether polyol
into the polymer (Example 40)~ Again the change~ in physical
properties can be observed.
The Tg of the formulations of these ex~mples was
determined by mechanical spectrometry ~M.S.) and differential
scanning calorimetry (DSC) to be as follows~
Polymer M.S. DSC
of Example Tq ( C) Tg ( C)
39 50.9-56.0 21
30.9 11
Thus the mixture of the PTNG polyether polyol with
the polycar~onate polyol resulted in a significant lowering of
the Tg (in degrees Centigrade). Thus, this polyol mixture
increases the cold cracking and low temperature impact
properties of the resulting linear polyurethane polymer.
Examples 41-45: Table VI (A~B) illustrates the reproducibility
of the invention by listing several formulations which were
made at different times on different days.
Examples 46-48
As described above, most o~ the elastomers of the
Examples were made using a solution polymerization technique
and then dried for testing and experimental use. This
technique is not a 6uitable process for use in commercial
manufacturing, and other methods of polymerization can be used.
One is to mix together the polyol(s) and diol(s) and then feed
this stream with a stream of isocyanate to an intensive mixer.
The two streams when mixed are heat2d to initiate
wo ~/11309 2 0 4 7 ~ 7 8 PCT/~'S90/01477
-20-
polymerization and extruded as a polymer (one ~hot). Another
approach is to first make prepolymers from the polyol(s) using
an excess of isocyanate and then to extend this material with
the diol(s) in the presence of hQat. Two experiments were
conducted in an attempt to simu]Late and evaluate these two
approaches. In both cases, the formula o~ Example 40 was used.
The one-shot experiment was conducted by weighing the polyols
and diol into a plastic container and mixing w811 under
nitrogen. The appropriate ~mount o~ LF-179 was then added,
mixed well, capped under nitrogen and placed in an oven at 9OC
overnight. The prepolymer approach was conducted by mixing the
polyols thoroughly with an excess of isocyanate (per formula),
followed by capping and heating for two hours at 85C. After
removing the sample from the oven, an appropriate amount of
diol was added, quickly mixed, capped and returned to a 9OC
oven overnight.
Table VII (A&B) gives a comparison of a solution cook
to a one-shot and a prepolymer cook. In all cases, flow
temperature is still lower than a comparable unmodified MDI
polymer and physical properties are very similar. Working
these polymers on a rubber mill indicates that the prepolymer
approach may actually yield a lower temperature processing
polymer than the one-sho~ approach. Also, the prepolymer
approach provides a much clearer polymer which is a sign of
better uniformity and compatibility. Therefore the prepolymer
approach is preferred although the one-shot approach will
indeed yield acceptable polymer~ and, it is seen that a new
linear polyurethane elastomers useful for a wide variety of
application can be prepared.
While it i5 apparent that the invention herein
disclosed is well calculated to fulfill the objects above
stated, it will be appreciated that numerous modifications and
embodiments may be devised by those skilled in the art, and it
is intended that the appended claims cover all such
modifications and embodiments as fall within the true spirit
and scope of the present invention.
2 0 ~ 7 6 7 8
TABLE l(A) FQRMULATIONS
ISOCYA- PRlMARY SECONDARY EQUIV WEIG~IT PREPOL FINAE
EXAMPLE NATE _POLYOL POLYOL RATIO RATIO_ NCO/OH _ NCO~Oli
1 LF-179 DU~ACARB 120 POLYMEC 2000 2.410 1.0~5 2,503 0.981
2 HDI DURACARB 120 POLYMEG 2000 2.410 1.025 3.340 0.980
3 LF-179 DVRACARB 120 POLYMEC 2000 3.565 1.516 2.600 0.950
4 MDI DVRACARB 120 POLYMEG 2000 3.565 1.516 1.478 0.950
LF-179 POLYMEG 1000 _ _ 2.377 0.950
6 MDI POLYMEG 1000 _ _ 3.171 0.950
7 LF-179 DURACARB 122 POLYMEG 2000 3.546 2.079 3.163 0.950
8 MDI DURACARB 122 POLYMEG 2000 3.546 2.079 4.220 0.951
9 LF-179 DURACARB 124 POLYMEG 2000 1.575 1.512 4.471 0.950
MDI DURACARB 124 POLYMEG 2000 1.575 1.513 1.517 0.950
11 LF-179 FORM-REZ 1.970 0.980
44-112
12 MDI FORM REZ _ 2 S33 0 980
44-112
oess: 1. Equivalene ~nd wei~ht ratio refer to ehe ratlo of prlmary ~o
secondnry polysl by equivalents or ~elght, respectively.
2. Each formulat~on coneains 1,4-butane diol as an ~xtender ln nn
amount necessary to ~chleve the final NCO/O}I ratlo.
~ 90/1~309 2 0 ~ 7 ~ 7 8 PCI/U~90/U14~7 ~
--22 -
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2~7~78
-23-
TABLE II(A) - FORMULATIONS
ISOCYA- PRIMARY SECONDARY EQUIV UEIGHT PREPOL FI~AL
EXAMPLE NATE POLYOL POLYOL RATIO _ RATIO NCO/OH NCO~OII
13 LF-179 DURACARB 120 POLYMEG ZOOO 3.681 1.565 2.618 0.952
14 ISO.181 DURACARB 120 POLYMEG 2000 3.558 1.512 2.606 0.951
15 MP-102 DURACARB 120 POLYMEG 2000 3.558 1.512 2.606 0.951
16 MON PF DURACARB 120 POLYMEG 2000 3.558 1.512 2.606 0.950
otes: 1. Equlvalent snd welght ratlo refer to the ratlo of prlmary to
secondary polyol by equivalents or welght, respectively.
2. Esch formulation cont~ins 1,4-butane dlol as an extender in an
amount necessary to achleve the final NCO/OH ratlo.
WO 90/1 1309 2 0 ~ 7 ~ 7 8 PCr/VS90/0~477
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-25-
TABLE~ A) - FO~MULATIONS
ISOCYA- PREPOL FINAL
EXAMPLE NATE POLYOL NCO/OH NCO/OH
17LF-179 DURACARB 120 2.477 0.992
18LF-179 DURACA~B 120 2.477 0.992
19LF-179 DURACARB 120 2.477 0.992
20 MDI DUi~ACARB 120 2~475 0.990
21 MDI DUR~C~RB 120 2.700 0.990
22 MDI DURACARB 120 2.901 0.990
Noce: Each formulstLon contalns ].,4-bueane dlol as an
extender as necessary to achleve the flnal NCO/Oil
ratlo~
WO ~0/ 1 1 30~
2 ~ ~ 7 6 7 ~ PCI/US90~014,7
--26--
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-27-
TABLE_IV(A) - FORMULAIIONS
ISOCYA- PRIMARY SECONDARY EQUIV WEICHT PREPOL FINAL
EXAMPLE NATE POLYOLPOLYOL RATIO RATIO NCO/OH NCO/OH
23 LF-179 DURACARB 120 POLYMEG 1000 B.9~8 7.677 2.480 0.977
24 LF-179 DURACARB 120 POLYMEG 2000 8.996 3.949 2.480 0.977
LF-179 DURACARB 120 POLYMEG 1000 3.995 3.412 2.479 0 977
26 LF-179 DURACARB 120 POLYMEG lOOO 2.999 2.562 2.475 0.980
27 LF-179 DURACARB 120 POLYMEG 1000 2.999 2.562 2.475 0.980
28 LF-179 DURACARB 120 POLYMEG 1000 2.327 1.988 2.481 0.977
29 LF-179 DURACARB 120 POLYMEG lOOO 2.334 1.993 2.099 0.980
LF-179 DURACARB 120 POLYMEG 1000 1.498 1.280 2.478 0.977
31 LF-179 DURACARB 120 POLYMEG 2000 2.410 1;025 2.826 0.983
32 LF-179 DURACARB 120 POLYMEG 1000 0.999 0.853 2.478 0.977
33 LF-179 DURACARB 120 POLYMEG 2000 2.333 1.025 2.481 0.977
36 LF-179 DURACARB 120 POLYMEG 2000 2.333 1.025 2.481 0.977
LF-179 DURACARB 120 POLYMEG 2000 2.410 1.025 2.503 0.981
36 LF-179 DURACARB 120 POLYMEG 2000 2.410 1.025 2.120 0.984
37 LF-179 DURAC~RB 120 POLYMEG 2000 1.032 0.439 2.520 0.9~3
38 LF-179 DURACARB 120 DURACARB 122 1.000 0.725 2.475 0.990
Notes: 1. Equivalent and weight ratio refer to the ratio of primary to
secondary polyol by equivalents or wel~ht, rcspectively.
2. Esch formulation contains 1,4-bueane diol as an extender in an
amount necessary to achieve the final NCO/OH ratio.
WO 90/1 1309
2 0 ~ 7 6 7 ~ Pcr/~tstgoto~77 -
3~ -28-
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-30-
TABLE V(A~ - FORMVLATIONS
ISOCYA- PRIMARY SECONDARY EQUIV UEI~HT PREPOL FIN~L
EXAMPLE NATE POLYOL POLYOL RATIO RATIO NCO/OH NCO/Oii
39 LF-179 DURACARB.120 _ 2.477 0.992
40 LF-179 DURACARB 120 POLYMEG 2000 3.565 1.516 2.600 0.950
Noees: 1. Equivalent and weight ratio refer to the ratio of primary to
secondary polyol by equivnlents or ~eight, respectively.
2. Each formulation contains 1,4 butane diol as an extender in an
amount necessary to achleve the final NCO/OH ratio. - `,
-
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W O 90/11309 2 0 ~ ~ 6 7 8 PCTfUS9U/01~77
-32-
TABLE VI(A) - FORMULATIONS
ISOCYA- PRIHARY SECONDM Y EQUIV WElGHT PREPOL FIN~L
XAMPLE NATE _ POLYOLPOLYOL RATIO RATIO NCO/OH NCO/OII
41 LF-179 DURACARB 120 PoLyMFG 2000 2.333 1.025 2.481 0.977
42 L~-179 DURACARB 120 POLYMEG 2000 2.333 1.025 2.481 0.977
43 LF-179 DURACARB 120 POLYMEG 2000 2.410 1.025 2.503 0.981
44 LF-179 DURACARB 120 POLYMG 2000 3.565 1.516 2.60Q 0.950
LF-179 DURACARB 120 POLYMEG 2000 3.565 1.516 2.600 0.950
__ !oces: 1. Equlvalent and weight ratio refer to the r~tio of primary to
secondary polyol by equivalents or weighe, respsctively.
2. Each formulstlon contsins 1,4-butane diol as an extender in an
amount necessary to achieve the final NCO/OH ratio.
WO 9~1 130~ 2 ~) ~ 7 6 7 ~ PCT~,'S~0/01477
--33--
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--3~--
TABLE VII(A) - FORMULATIONS
ISOCYA- PRIMARY SECONDARY EQUIV WEICHT PREPOL FINAL
XAMPLE NATE POLYOL POLYOL RATIO RATIO NCO~OH NCO/O
46 LF-179 DURACARB 120 POLYHEG 2t)00 3.565 1.516 2.600 0.950
47 LF-179 DURACARB 120 POLYMEG 2000 3.565 2.079 2.600 0.950
48 LF-179 DURACARB 120 POLYMEG 2000 3.565 2.079 2.600 0.950
otss: 1. Equivalent and waight raelo refer to the ratio of primary to
secondary polyol by equi~alents or weight, respecti~ely.
2. Each formulaeion contains 1,4-bueane diol as an extender in an
amount necessary to achieve the final NCO/OH ratio.
W9~/11309 2 ~ 4 ~ ~ 7 ~ PCr/US~0/01-~77
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