Polyurea gel compositions and articles therefrom

Crosslinkable gel compositions cure rapidly to provide gel compositions which possess superior combinations of chemical and physical properties and aging resistance. These compositions are particularly useful for environmentally protecting substrates, especially electrical conductors, connectors, and splices and for sealing around jacketed cables, for example where they enter splice cases.

FIELD OF THE INVENTION 
This invention relates to cured gels and curable compositions for providing 
gels. 
BACKGROUND OF THE INVENTION 
Cured gels including polyurethane gels have long been used to seal 
electrical components and to protect metallic structures from corrosion, 
for example, by sea-water. For example, polyurethane gels have been cast 
in place around multiconductor cable joints by mixing the gel forming 
components (di- or polyisocyanates and hydroxy-terminated polybutadienes 
or polyesters) and a diluent and then pouring the mixture quickly around 
the joint and allowing it to cure in place. The curing of 
polyisocyanate/diol mixtures is relatively slow (for example, several days 
even with catalyst added) at room temperature. In recent years, as 
disclosed inter alia in U.S. Pat. Nos. 4,600,261 and 4,634,207 (Debbaut), 
the disclosures of which are incorporated herein by reference for all 
purposes, articles comprising precured gels have been used to protect 
electrical contacts and other substrates. 
Other known uses for gels include the insulation of busbars and other 
electrical components using silicone gels and non-silicone gels, 
especially butyl gels as described by Chang and Toy in EP 0174165 (1986) 
and by Toy in EP 0229102 (1987), which describes, inter alia, the use of 
such gels as insulating and stress grading compositions in high voltage 
terminations and connectors. The disclosure of each of these applications 
is incorporated herein by reference. 
The polyurethane gels used by the prior art have excellent short term 
physical properties but have poor aging resistance, i.e. they are poor in 
such long term chemical and physical properties as hydrolytic and thermal 
stability, resistance to moisture and resistance to compression set 
especially at higher temperatures within the anticipated service range. In 
addition, polyurethane gels can under certain circumstances extract 
plasticizer from, or otherwise impair the functionality of, poly(vinyl 
chloride) insulation. 
SUMMARY OF THE INVENTION 
We have discovered novel gel compositions which are useful for sealing and 
environmentally protecting substrates, especially electrical connections. 
The novel compositions exhibit unexpectedly superior and useful 
combinations of tensile strength, elongation, toughness and compatibility 
with substrates including those comprising poly(vinyl chloride), accepting 
high levels of diluent without significant syneresis, while maintaining 
beneficial tack properties which are valuable for gel sealant 
compositions. 
In one aspect this invention provides a composition comprising a 
crosslinked polyurea. The crosslinked polyurea is preferably present as a 
gel. The composition and, preferably, also the polyurea gel, has a Voland 
hardness of from 1 to 500 g. and an ultimate elongation of at least 50%. 
Preferably the polyurea gel comprises from at least 25% by weight to 95% 
by weight of a diluent (based on the combined weights of the polyurea and 
the diluent). More preferably the polyurea gel comprising from at least 
25% by weight to 95% by weight of a diluent has a gel fraction of 5% by 
weight to 75% by weight of the combined weights of the polyurea and 
diluent. Preferably, the diluent comprises a liquid which is compatible 
with (e.g. swells) the crosslinked polyurea and which is preferably 
unaffected chemically by the conditions used to prepare the crosslinked 
polyurea. 
In another aspect of this invention the average molecular weight between 
urea groups in the polyurea is less than 500 g per mole of polymer, for 
example, less than 250 g per mole of polymer. Gels having such densities 
of urea groups are particularly useful where a high dielectric constant is 
needed. In some applications, an average molecular weight between urea 
groups greater than 500 may be preferred, for example, at least 1000 g per 
mole of polymer, or even at least 2000 g per mole of polymer may be 
desirable, for instance where a lower dielectric constant gel is needed. 
The term "crosslink" in this specification means a covalent bond formed by 
chemical reaction between two crosslinkable sites from which sites depend 
a total of three or more molecular segments; or at least two covalent 
bonds, each formed by chemical reaction between a crosslinkable site and 
an intermediate molecule, so that the residue of the molecule has at least 
three molecular segments depending therefrom. Typically the intermediate 
compound is a low molecular weight compound or a low molecular weight 
oligomeric material containing at least three crosslinkable sites. A 
crosslink can be trifunctional (a T-link, i.e. a crosslink having three 
molecular segments depending therefrom), or tetrafunctional (an H-link, 
i.e. a crosslink having four molecular segments depending therefrom) or 
can have yet higher functionality. 
In another aspect, this invention provides a crosslinkable composition 
which when fully cured has a Voland hardness of from 1 to 500 g. and an 
ultimate elongation of at least 50%, the curable composition comprising a 
first organic compound containing amine groups, a second organic compound 
containing isocyanate groups or isocyanate precursor groups and a diluent 
in an amount from 25% by weight to 95% by weight of the combined weights 
of the first organic compound, the second organic compound and the 
diluent. In a preferred embodiment the first organic compound is a 
polyamine containing an average of n amine groups per molecule and the 
second organic compound is a polyisocyanate or polyisocyanate precursor 
containing an average of m isocyanate or isocyanate precursor groups per 
molecule, where each of n and m are at least 2 and the sum of n and m is 
at least 4.1, the composition having a gel time (as defined hereunder) in 
the absence of added catalyst of less than 600 seconds at 25.degree. C. 
In another aspect this invention provides a kit comprising at least two 
containers, each of said containers comprising at least one material 
selected from the group consisting of: 
(1) a first organic compound containing amine groups; 
(2) an second organic compound containing isocyanate groups or isocyanate 
precursor groups; and 
(3) a diluent which is inert to reaction with the first organic compound 
and inert to reaction with the second organic compound, the total amount 
of the diluent in the containers being from 25% by weight to 95% by weight 
of the combined weights of the first and second organic compounds and the 
diluent in the containers; 
the division of materials between the containers being such that the first 
organic compound and the second organic compound are stable when the 
containers are maintained at room temperature (25.degree. C.) under dry 
conditions for 6 months; 
The contents of the containers when mixed and fully cured providing a 
crosslinked polyurea gel which has a Voland hardness of from 1 to 500 g. 
and an ultimate elongation of at least 50%. 
Preferably in this aspect of the invention the first organic compound is a 
polyamine containing an average of n amine groups per molecule and the 
second organic compound is a polyisocyanate or polyisocyanate precursor 
containing an average of m isocyanate or isocyanate precursor groups per 
molecule, where each of n and m are at least 2 and the sum of n and m is 
at least 4.1. 
Another aspect of the invention provides a method of forming a polyurea gel 
having a Voland hardness of from 1 to 500 g and an ultimate elongation of 
at least 50% which method comprises reacting together 
(1) a first organic compound containing amine groups; and 
(2) a second organic compound containing isocyanate groups or isocyanate 
precursor groups; 
in the presence of a diluent, which is inert to reaction with the first 
organic compound and inert to reaction with the second organic compound, 
in an amount of from at least 25% by weight to 95% by weight of the 
combined weights of the first organic compound, the second organic 
compound and the diluent. Preferably in this aspect of the invention the 
first organic compound is a polyamine containing an average of n amine 
groups per molecule and the second organic compound is a polyisocyanate or 
polyisocyanate precursor containing an average of m isocyanate or 
isocyanate precursor groups per molecule, where each of n and m are at 
least 2 and the sum of n and m is at least 4.1. 
In another aspect this invention provides an article, for protecting a 
substrate, comprising a composition which comprises a polyurea gel and 
which has a Voland hardness of from 1 to 500 g. and an ultimate elongation 
of at least 50%. Preferably the article also comprises means for deforming 
the cured gel into contact with the substrate, more preferably means for 
deforming the cured gel into close and conforming contact with the 
substrate. 
In another aspect, this invention provides a substrate protectively 
encapsulated at least in part by a composition which comprises a cured 
polyurea gel and which has a Voland hardness of from 1 to 500 g. and an 
ultimate elongation of at least 50%. 
In another aspect, this invention provides a method of encapsulating a 
substrate which comprises surrounding the substrate with a mixture 
comprising: 
(1) a first organic compound containing amine groups; 
(2) a second organic compound containing isocyanate groups or isocyanate 
precursor groups; and 
(3) a diluent, which is unaffected chemically by the reaction between the 
first organic compound and the second organic compound, said diluent being 
present in an amount of from at least 25% by weight to 95% by weight of 
the combined weights of the first organic compound, the second organic 
compound and the diluent; and 
curing the mixture in contact with the substrate. Preferably in this aspect 
of the invention the first organic compound is a polyamine containing an 
average of n amine groups per molecule and the second organic compound is 
a polyisocyanate or polyisocyanate precursor containing an average of m 
isocyanate or isocyanate precursor groups per molecule, where each of n 
and m are at least 2 and the sum of n and m is at least 4.1. 
A still further aspect of this invention provides a method for protecting a 
substrate comprising: 
(1) providing a cured polyurea gel; 
(2) applying said cured polyurea gel to said substrate such that said 
composition substantially encapsulates at least a portion of said 
substrate. 
Another aspect of this invention provides a method for protecting a 
substrate comprising: 
(1) providing a composition which comprises a crosslinked polyurea, the 
composition having a Voland hardness of from 1 to 500 g and an ultimate 
elongation of at least 50%; 
(2) applying the composition to the substrate such that the composition 
substantially surrounds at least a portion of the substrate. 
Another aspect of this invention provides a method for preparing a 
composition of predetermined dielectric constant comprising: 
(A) selecting a blend of diluents each of which exhibits a dielectric 
constant different from any other of the diluents selected, the weight 
ratios of the diluents being chosen such that the blend has a desired 
dielectric constant; and 
(B) incorporating the blend into a composition comprising a first organic 
compound containing amine groups; a second organic compound containing 
isocyanate groups or isocyanate precursor groups; and 
curing the composition to form a crosslinked polyurea gel; the relative 
proportions and amount of the blend being such that the composition 
exhibits the predetermined dielectric constant. 
In many of these aspects of the invention it is advantageous for the 
diluent to comprise a mixture of components, at least one of which is a 
liquid at room temperature and exhibits a dielectric constant that differs 
from at least one of the other components.

DETAILED DESCRIPTION OF THE INVENTION 
In the present invention the average molecular weight between crosslinks 
(M.sub.c) of the cured polyurea gel is preferably at least 2,000, for 
example at least 4,000, more preferably at least 7,500, for example at 
least 10,000 and, in some embodiments, at least 20,000. The Voland 
hardness of the composition is preferably 2 to 375 g, particularly 2 to 
125 g, especially 2 to 40 g. The ultimate elongation of the composition is 
preferably at least 250% and particularly at least 650%, for example, at 
least 700%, especially at least 800%. 
The first (amine containing) compound used in preparing these novel gels 
can be a single compound or a mixture of compounds, for example, one or 
more compounds each having at least three amine groups per molecule and/or 
one or more compounds each having at least two amine groups per molecule. 
The second (isocyanate- or isocyanate precursor-containing) compound can 
likewise be a single compound or a mixture of compounds, for example, one 
or more compounds each having at least three reactive groups per molecule 
and/or one or more compounds each having at least two reactive groups per 
molecule. The molar equivalent ratio of the first compound or combination 
of compounds to the second compound or compounds is preferably such that a 
majority of the molecules of reactants are joined to one or more other 
molecules by at least two crosslinks (that is form closed loops which 
comprise at least part of a three dimensional network). More preferably at 
least 50%, for example at least 65%, preferably at least 75% of the 
crosslinks form such closed loops. For this purpose the molar equivalent 
ratio of the first compound or compounds to the second compound or 
compounds is preferably from 0.67 to 1 to 1.5 to 1, for example, 0.8 to 1 
to 1.25 to 1, more preferably 0.9 to 1 to 1.11 to 1. 
The polyurea gel may be pre-cured (that is, cured before being brought into 
contact with the substrate), or it can be cured after coming into contact 
with the substrate. If the gel is pre-cured, it is preferably associated 
with means for deforming the cured polyurea gel into contact with the 
substrate and/or means for maintaining the cured polyurea gel in contact 
with the substrate, preferably by compression. 
Preferably cured polyurea gels and gel compositions of the present 
invention have a cohesive strength greater than the adhesive strength of 
the gel or gel composition. 
The compositions of the invention preferably contain at least 25%, for 
example at least 30%, more preferably at least 45%, for example, at least 
60% of a diluent, the percentages being by weight of the combined weights 
of the crosslinked polyurea and the diluent. Amounts of diluent 
corresponding to these ranges are preferably used in preparing the gels 
and/or gel compositions. 
Preferably the first organic compound has the formula 
EQU Q--{[--A--].sub.h --D}.sub.i-1 --A--Q 
and the second organic compound has the formula: 
EQU P--{[--A--].sub.j --E}.sub.k-1 --A--P 
where each of h, j, i and k, which may be the same or different, is an 
integer having a value of at least 1 such that the sum of h, j, i and k is 
at least 20 and less than 200; 
each of the Q radicals, which may be the same or different is linked 
directly to a carbon atom of an A radical and is a primary or secondary 
amine group; 
each of the P radicals, which may be the same or different is linked 
directly to a carbon atom of an A radical and is an isocyanate or 
isocyanate precursor group; 
each of the A radicals, which may be the same or different, 
EQU --R--, --R--O--R--, --R--CO.sub.2 --R--, -R--NH--CO--R--, --R--NH--CO.sub.2 
--R--, --R--S--R--, --O--Si(R').sub.2 --or --O--Si(R').sub.2 --R-- 
where each of the R radicals, which may be the same or different, is an 
alkylene, substituted alkylene, alkenylene, substituted alkenylene, 
arylene or substituted arylene radical, and each of the R' radicals, which 
may be the same or different is an alkyl, substituted alkyl, aryl or 
substituted aryl radical; 
each of the D radicals, which may be the same or different, is a valence 
bond or a secondary amine group or an alkylene, substituted alkylene, 
alkenylene, substituted alkenylene, arylene or substituted arylene 
radical; and 
each of the E radicals, which may be the same or different, is a valence 
bond or an alkylene, substituted alkylene, alkenylene, substituted 
alkenylene, arylene or substituted arylene radical. 
The term valence bond means a single covalent bond directly linking two 
atoms of the main chain of the first compound or the second compound 
together. 
An isocyanate precursor group is a group that is capable of forming an 
isocyanate group under the reaction conditions used to prepare polyurea 
gels, for example, a blocked isocyanate group, that is, an isocyanate 
group that has been treated (reacted) with a compound containing an active 
hydrogen atom (such as substituted or unsubstituted phenols, oximes or 
alkyl substituted malonates) to produce a relatively non-reactive compound 
from which the isocyanate may be regenerated by heating, for example to 
150.degree. C. Examples of such relatively unreactive compounds include 
the carbamates produced by the reaction of an isocyanate with an alkyl 
substituted phenol or an aromatic oxime. The blocking group may be 
released by heat alone or by reacting the blocked isocyanate with a 
monomeric or polymeric compound also containing active hydrogen atoms such 
as aliphatic or aromatic amines or alcohols. 
Suitable amines include but are not limited to alpha-amino-propyl, 
omega-amino terminated polypropylene oxides with molecular weights of from 
200 to 20,000, alpha-amino-ethyl, omega-amino terminated polyethylene 
oxides with molecular weights of from 200 to 20,000, alpha-amino-ethyl, 
omega-amino terminated polytetramethylene oxides with molecular weights of 
from 250 to 25,000 and the like; dimer diamine which has the approximate 
structure: 
##STR1## 
and amine rich polyamide resins such as the reaction product of dimer 
diacid, which has the approximate structure: 
##STR2## 
or other dicarboxylic acids with an excess of a substituted or 
unsubstituted alkylene or arylene diamine; amine terminated amine-epoxy 
adducts such as the reaction product of a bisphenol A epoxy resin with 
diamines such as diethylene triamine; 
4,4'-diamino-3,3'-dimethyldicyclohexylmethane; aromatic amines such as 
diaminodiphenyl sulfone, ethylenebisaniline, methylenedianiline, 
diethyltoluenediamine, 3,5-dimethylthio-2,4-toluenediamine and the like; 
amine terminated polybutadienes, amine terminated butadiene-acrylonitrile 
copolymers and amine terminated polyorganosiloxanes such as 
aminopropyldimethyl terminated polydimethylsiloxanes, aminobutyldimethyl 
terminated polydimethylsiloxanes and the like. Amongst the suitable amine 
rich polyamides may be mentioned those available from Henkel Corporation 
under the tradenames Versamid 100, Versamid 115, Versamid 125 and Versamid 
140. Among the suitable epoxy amine adducts may be mentioned those 
available from Henkel Corporation under the tradename Versamine, such as 
Versamine C30. 
Suitable polyisocyanates or precursors thereof include organic isocyanates 
having at least two isocyanate groups per molecule. The polyisocyanates 
can be of low, high or intermediate molecular weight and can be any of a 
wide variety of organic polyisocyanates including ethylene di-isocyanate, 
trimethylene di-isocyanate, dodecamethylene di-isocyanate, hexamethylene 
di-isocyanate, hexamethylene di-isocyanate trimer, tetraethylene 
di-isocyanate, pentamethylene di-isocyanate, propylene-1,2-diisocyanate, 
2,3-dimethyltetramethylene di-isocyanate, 1,4-diisocyanato cyclohexane, 
methyl-hexamethylene di-isocyanate, 
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 
cyclopentene-1,3-diisocyanate, p-phenylene di-isocyanate, naphthalene 
di-isocyanate, 4,4'-diphenylene methane di-isocyanate, 4,4'-diphenylene 
propane di-isocyanate, tetramethylxylylene di-isocyanate (TMXDl), 
1,2,3,4-tetraisocyanato butane, butane-1,2,3-triisocyanate, and 
isocyanate-containing linear and branched aromatic, polyisocyanates which 
may be polymeric in nature such as polyether and polyester prepolymers 
polyisocyanates. Representative examples of such prepolymers are sold, for 
example, by Mobay Corporation under the tradenames Desmocap llA and 
Desmocap 12. 
The diluent may be any organic liquid having the desired degree of 
compatibility with the polyurea. Thus crosslinked gels of the invention 
can be prepared having a wide range of solubility parameters. In 
particular, this invention can provide gel compositions of higher 
solubility parameter than has been contemplated hitherto for uses such as 
those described hereinabove. Accordingly, in some applications, preferred 
diluents exhibit solubility parameters of at least 7.6 Hildebrands, more 
preferably at least 8.0 Hildebrands and most preferably at least 9.0 
Hildebrands. Suitable diluents include mineral oils, aliphatic hydrocarbon 
oils such as those sold under the trademark "Permethyl" and having the 
general structure H[--C(CH.sub.3).sub.2 ].sub.n --H where n is greater 
than 10 and having viscosities of about 35 to about 50 cps; at least 
partially aromatic, preferably polynuclear, hydrocarbon oils, such as 
partially hydrogenated terphenyl; esters of aliphatic, aromatic and 
inorganic acids, such esters including diethyl hexyl phthalate, 
ditridecylphthalate, triethylhexyl trimellitate, dibutyl phthalate, butyl 
benzyl phthalate, diethyl phthalate, ethylhexyldiphenyl phosphate, 
tricresyl phosphate, and t-butylphenyl diphenyl phosphate; and 
sulphonamides, such as N-ethyl-o,p-toluene sulphonamide; silicone fluids 
such as dimethylsilicones with viscosities of from about 1 to about 
10.sup.6 centipoises (cp) (as described by Dubrow in published 
international patent application WO 90/10035 (1990), the disclosure of 
which is hereby incorporated for all purposes within); and the like and 
mixtures of any two or more of the above. Preferably the solubility 
parameters of the gel and the solubility parameter of the diluent (or 
average solubility parameter of the diluents, if there is more than one 
liquid diluent) differ by less than 2 Hildebrands, more preferably by less 
than 1 Hildebrands most preferably by less than 0.5 Hildebrands. 
If desired, the reactants may also include one or more hydroxy compounds as 
diluents. We have found that the amines react so much more rapidly than do 
hydroxy compounds with the isocyanate or isocyanate precursor compounds 
that the latter act essentially as inert diluents. 
The curable compositions of this invention and the compositions made 
according to this invention may contain various additional ingredients 
such as flame retardants, corrosion inhibitors, antioxidants, UV light 
stabilizers, fungicides and other biocides, pigments and fillers to 
enhance or decrease thermal or electrical conductivity and fillers to 
adjust density or other physical properties. Such additives or fillers 
also may be used to regulate or affect the rate of extent of cure and 
crosslinking and affect the overall cost of the final composition. 
Particularly useful ingredients for incorporation in gels of the present 
invention are described by Dittmer and Dubrow in U.S. Pat. No. 4,852,646 
(1989) and by Holland and Rost in published European patent application EP 
0,324,255 (1989), the disclosures of which are incorporated by reference 
herein for all purposes. 
Advantageously, the polyurea gels of the invention contain stabilizers and 
antioxidants, for example, one or more of 1,6-hexamethylene 
bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), tetrakis[methylene 
3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, octadecyl 
3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, 
N,N'-bis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate] hydrazine, 
thiodiethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), triethylene 
glycol bis(3-(3'-tert-butyl-4'-hydroxy-5'-methylphenyl)propionate, 
octadecyl-3(3',5'-di-tert-4'-hydroxyphenyl)propionate, N,N'-hexamethylene 
bis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 
2-methyl-4,6-bis[(octylthio)methyl]phenol, 
4,4'-thiobis-6-tert-butyl-m-cresol), 2,2'-methylene 
bis(4-methyl-6-tert-butyl phenol), 4,4'-methylene bis(2,6-di-tert-butyl 
phenol), di-tert-butyl phenol, 
2,2'-methylene-bis(4-ethyl-6-tert-butyl)phenol, the reaction product of 
dicyclopentadiene and ortho-tert-butylhydroxytoluene, 
2(2'-hydroxy-5'-methylphenyl)benzotriazole, 
2(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 
2(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 
bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, the condensation product 
of dimethyl succinate with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine 
ethanol, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 
{[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butyl-bis(1,2,2,6,6-pe 
ntamethyl-4-piperidinyl) ester, nickel 
bis[O-ethyl(3,5-di-tert-butyl-4-hydroxybenzyl]phosphinate, 4,4'-bis 
(.alpha.,.alpha.-dimethylbenzyl) diphenylamine, products of the 
condensation reaction of diphenylamine with acetone, arylated 
diphenylamine, octylated diphenylamine, 
poly((6-((1,1,3,3-tetramethylbutyl)amino)-s-triazine-2,4-diyl)((2,2,6,6-te 
tramethyl-4-piperidyl)imino)hexamethylene((2,2,6,6-tetramethyl-4-piperidyl) 
imino)), zinc dialkyl dithiocarbamates, zinc dialkyldithiophosphates, 
dialkyl thiodipropionates, distearylpentaerythritol diphosphite, 
trisnonylphenylphosphite, dilauryl hydrogen phosphinate, 
tris(3,5-di-tert-butylphenyl) phosphite, 
tetra(3,5-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, 
polycarbodiimide and the like. 
For greater oxidative stability it is preferred that the polyurea gels of 
the invention be "amine rich", that is that the ratio of amine to 
isocyanate in the starting materials used to prepare the polyurea be 
greater than 1, for example, greater than 1.02 to 1 more preferably 
greater than 1.05 to 1, for example greater than 1.1 to 1. 
The term "gel time" as used in this specification means the time which 
elapses between that time at which the isocyanate, amine and other 
ingredients are first mixed together and that time at which the mixture 
ceases to flow under its own weight. This moment may be ascertained quite 
simply by tipping the container in which the reacting ingredients are 
contained and observing if any flow occurs. Reproducibilities of +25% can 
be obtained. For some applications the gel time at 25.degree. C. is 
preferably less than 900 seconds, preferably less than 600 seconds, more 
preferably less than 600 seconds, for example less than 200 seconds, most 
preferably less than 100 seconds and especially less than 50 seconds. For 
other applications, where a longer open time is desirable so that the 
uncured gel can be worked with, such as transferring from one container to 
the other, longer gel times, in the tens of minutes or even in hours, is 
preferable. Those skilled in the art will determine readily which gel time 
is most desirable for their particular application. An advantage of this 
invention is that, by selecting the appropriate combination of isocyanate 
and amine components, compositions with different cure times can be 
formulated. 
Where a longer cure time is desired, the gel time can be made longer by 
blocking the amine groups with a ketone or aldehyde, such as has been done 
with epoxy resin coatings. The carbonyl groups in ketones and aldehydes 
react with amine groups to form imine groups, which are unreactive with 
isocyanate groups. In the presence of water (for example atmospheric 
moisture), imine groups are hydrolyzed to regenerate the amine groups, 
which are reactive. By mixing an isocyanate component with an amine 
component having blocked amine groups, the gel time can be increased, for 
example from about two minutes to over 24 hours. 
FIG. 4 shows the effect of when different amounts of acetone were allowed 
to react with the amine component (Jeffamine T5000) of a gel formulation 
for different amounts of time, before mixing with the isocyanate component 
(dimer di-isocyanate). Increasing the amount of acetone increased the gel 
time from about 2 min to over 60 min, indicating deactivation of the 
amine. A greater effect was observed after a 40-50 min reaction time 
compared to a 30-40 min reaction time, indicating that the deactivation 
process (reaction of amine with the ketone) is still incomplete after 
30-40 min. 
FIG. 5 compares the effectiveness of three different ketones, acetone, 
2-butanone, and methyl isobutyl ketone (MIBK) in increasing the gel time 
of a gel based on dimer di-isocyanate, Jeffamine T-5000, and Therminol 66. 
Methyl isobutyl ketone is seen to be the more effective of the three. 
FIG. 6 shows the effect of increasing the stoichiometric ratio of MIBK on 
the gel time of a dimer di-isocyanate/Jeffamine T-5000 gel, after allowing 
the MIBK to react with the amine for 3 hr at 60.degree. C. and then 21 hr 
at room temperature. There is a plateau at higher MIBK levels, indicating 
complete reaction with the amine groups. 
FIG. 7 shows that although the gel time is affected by the addition of a 
ketone (in this instance 2-decanone), physical properties (as measured by 
the hardness) is little affected. FIG. 8 shows a similar effect is 
obtained with an aldehyde (dodecanal) on a gel made from Desmodur N-3300 
and Jeffamine D-4000 after a reaction time of 16 hr at 60.degree. C. plus 
one hr at room temperature. 
Numerous ketones and aldehydes can be used as blocking agents for amines. 
Suitable ketones and aldehydes include but are not limited to acetone, 
2-butanone (methyl ethyl ketone), methyl isobutyl ketone, 2-decanone, 
2-undecanone, 3-tridecanone, 3-decanone, 10-nonadecanone, 
4-hydroxy-4-methylpentanone, acetophenone, decanal, undecanal, dodecanal, 
benzaldehyde, and ethoxy-benzaldehyde. For applications where a volatile 
blocking agent is undesirable for one reason or another, higher molecular 
weight, less volatile blocking agents such as 2-decanone and 2-undecanone 
are preferred. 
The equilibrium between imine on the one hand and ketone (or aldehyde) and 
amine on the other hand is affected by the amount of ambient moisture 
present. Increasing the amount of ambient water pushes the equilibrium 
towards ketone (or aldehyde) and amine, and consequently decreases the gel 
time. This effect is illustrated graphically in FIG. 9 for a gel from 
dimer di-isocyanate and Jeffamine T-5000 blocked with 2-undecanone (19.5 
hr at 60.degree. C. plus 2.5 hr at room temperature). "One-part" gels with 
very long shelf lives can be made from dried blocked amine, isocyanate, 
and extender fluid. To get the gel to cure, one can simply expose the 
uncured gel to atmospheric moisture, or, preferably, add water to it. 
The invention is illustrated in the following Examples. 
EXAMPLE 1 
Preparation of Polyureas Using Isocyanates 
This procedure describes in general terms the method used to make 
formulations 1-1 to 1-15 listed below. Each gel is prepared using three 
basic ingredients, namely 
1) A mixture of tetramethylxylylenediisocyanate (TMXDI, available from 
American Cyanamid Co.) which has the following structure: 
##STR3## 
and dimer di-isocyanate (DDl 1410, available from Henkel Corporation) 
which has the approximate structure: 
##STR4## 
in the amounts specified in Table 2. 
2) An amine terminated polypropylene ether (either Jeffamine D-4000 which 
has a molecular weight of 4,000 and contains about two amine groups per 
molecule or the similar Jeffamine T-5000 which has a molecular weight of 
5,000 and contains about three amine groups per molecule. 
3) An inert diluent as identified in Table 1 below. 
TABLE 1 
______________________________________ 
Commerical or 
Abbreviated 
Name Chemical Name Supplied by 
______________________________________ 
DBP Dibutyl phthalate Eastman 
Kodak 
DTDP Ditridecyl phthalate Eastman 
Kodak 
Phosflex 362 
Diphenyl octyl/triphenylphosphate 
AKZO 
mixture 
DOP Dioctyl phthalate Ashland 
Chemicals 
Jayflex DTDP 
Ditridecyl phthalate Exxon 
Chemicals 
Therminol 60 
Ethyl benzene, benzylated 
Monsanto 
Chemicals 
Therminol 66 
Partially hydrogenated terphenyls 
Monsanto 
Chemicals 
Shellflex 371 
Hydrocarbon oil Shell 
Chemicals 
Santicizer 154 
t-Butylphenyl diphenyl phosphate 
Monsanto 
Chemicals 
Santicizer 141 
2-Ethylhexyl diphenyl 
Monsanto 
Chemicals 
Santicizer 160 
Butyl benzyl phthalate 
Monsanto 
Chemicals 
DEP Diethyl phthalate Eastman 
Kodak 
HB40 Partially hydrogenated terphenyls 
Monsanto 
Chemicals 
PPG-10225 Propylene glycol Union 
Carbide 
Ketjenflex 8 
N-Ethyl-o/p-toluene sulfonamide 
AKZO 
TOTM Tri-2-ethylhexyl trimellitate 
C. P. Hall 
______________________________________ 
We have found that the reaction of the isocyanate with an amine, even when 
highly diluted with an extender, is so rapid that two masterbatches, one 
for the isocyanate (Part A) and one for the amine (Part B), are highly 
desirable. These masterbatches generally contain equal volumes or equal 
weights of materials and are very rapidly mixed together to start the 
reaction. Part A contains the isocyanate, with part of the diluent(s), 
stabilizers and any fillers, etc. Part B contains the amine(s), the rest 
of the diluent(s) and stabilizers etc. 
In preparing gels in all of the following examples, the correct amounts of 
the ingredients were weighed on an analytical balance (accuracy 0.01 g) 
and blended to form Parts A and B. Part A and Part B were then mixed 
rapidly together (gel times as short as 10 seconds have been observed) and 
cast into beakers or onto flat sheets. Typically the gel was cast rapidly 
into a 6".times.6".times.0.125" (15.24.times.15.24.times.0.3175 cm) mold 
and cured at room temperature. Gel properties were measured after the gel 
had cured for 24 hours at room temperature. Elongation was determined 
using tensile bars die cut from the molded slabs using procedures 
described in ASTM D419. For hardness measurements 60 g mixed formulation 
were placed in 100 mL beakers and cured. The hardness was measured using a 
Voland-Stevens Texture Analyser Model LFRA-1000 with a 5 g trigger on a 
1/4 in (0.635 cm) ball probe. The probe was advanced down into the gel to 
a depth of 4 mm at a rate of 0.2 mm per second. Stress relaxation was 
measured as the % decrease in hardness when the hardness was measured 
again 1 minute after the initial hardness was measured with the probe 
being held at constant depth therebetween. Tack values were measured as 
the maximum force observed on withdrawing the probe from the gel after the 
hardness has been measured. Results obtained for gels prepared using DBP 
as diluent are given in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Exam- 
Weight 
Weight 
Weight 
Weight 
Hardness 
Tack 
Stress Relax- 
Gel Time 
ple No. 
DBP (g) 
DDI (g) 
D4000 (g) 
T5000 (g) 
(g) (g) 
ation (%) 
(sec) 
__________________________________________________________________________ 
2-1 20.00 
2.75 12.06 5.18 5 13 -- 60 
2-2 20.00 
2.79 10.32 6.89 13 33 36 35 
2-3 20.00 
2.90 8.60 8.60 40 34 18 30 
2-4 20.00 
2.82 6.88 10.33 
60 33 13 25 
2-5 26.00 
1.95 7.23 4.84 14 28 15 70 
2-6 26.00 
1.96 6.02 6.02 30 27 6.5 45 
2-7 26.00 
1.99 4.00 8.00 71 14 3.5 25 
2-8 26.00 
2.01 2.39 9.00 119 10 4.0 20 
2-9 29.62 
1.38 5.11 3.41 4 15 10 240 
2-10 
29.72 
1.39 4.26 4.26 17 12 13 100 
2-11 
29.80 
1.42 2.84 5.68 40 7 4.0 50 
2-12 
29.96 
1.42 1.70 6.02 73 2 4.5 40 
2-13 
32.00 
1.12 3.44 3.44 8 10 6.0 180 
2-14 
32.00 
1.13 2.29 4.58 25 6 1.2 70 
2-15 
32.00 
1.15 1.37 5.48 47 4 2.0 55 
__________________________________________________________________________ 
EXAMPLE 2 
Table 3 shows selected physical properties of gels prepared, using the 
procedure of Example 1, from various mixtures of a polyetheramine 
(Jeffamine D-2000 available from Texaco Chemical Co., which is an amine 
terminated polypropylene oxide and which has a molecular weight of 2,000 
and an average of two terminal amine groups per molecule) and T-5000 in 
the presence of various concentrations of dibutyl phthalate (DBP) or 
Phosflex 362 (diphenyloctyl/triphenyl phosphate mixture) as diluent. 
TABLE 3 
__________________________________________________________________________ 
Weight 
Weight Dielectric 
Sam- 
Diluent Isocyanate 
D2000 
T5000 
Hard- 
Gel constant of 
ple No. 
Type 
Wt. (g) 
Type Wt. (g) 
(g) (g) ness (g) 
time (sec) 
diluent 
__________________________________________________________________________ 
3-1 DBP 74.54 
DDI 3.85 
4.93 
14.79 
25 75 6.45 
3-2 362 74.54 
DDI 3.85 
4.93 
14.79 
25 75 7.52 
3-3 DBP 72.67 
TMXDI 
1.49 
-- 24.22 
110 240 6.45 
3-4 DBP 63.74 
DDI 4.61 
-- 29.75 
110 25 6.45 
3-5 DTDP 
44.86 
TMXDI 
0.80 
-- 14.15 
37 &gt;300 4.06 
3-6 DBP 30.00 
TMXDI 
0.61 
-- 10.00 
108 240 6.45 
__________________________________________________________________________ 
EXAMPLES 3 
Preparation of Polyureas Using Blocked Isocyanates 
This procedure describes in general terms the method used to make 
formulations of examples 4-1 to 4-19 listed below, which comprise gels of 
the invention. Each gel is prepared from four basic ingredients: 
1) The blocked isocyanate: Desmocap IIA and Desmocap 12 (both available 
from Mobay). Desmocap IIA (equivalent weight about 1750) is a 
trifunctional and Desmocap 12 (equivalent weight about 2470) a 
difunctional blocked isocyanate oligomer prepared from polypropylene 
glycol, toluene di-isocyanate and an alkyl phenol. 
2) The curative: an amine terminated polypropylene oxide (Jeffamine D-400 
or Jeffamine D-2000 available from Texaco Corporation) or 
4,4'-diamino-3,3'-dimethyldicyclohexylmethane (DDD, available from BASF). 
Jeffamine D-400 (molecular weight about 400) and D-2000 (molecular weight 
about 2,000) are difunctional amine terminated polypropylene ether 
oligomers. 
3) An antioxidant: Irganox 1035 available from Ciba Geigy. 
4) The diluent: a phthalate ester, ether dioctyl phthalate (DOP, obtained 
from Aldrich Chemical) or ditridecyl phthalate (DTDP, obtained from Exxon 
Chemical). 
Ingredient 3 is used at a concentration of 1% of the mixture for all the 
formulations. Ingredients were weighed on an analytical balance (accuracy 
0.01 g) then mixed with an overhead stirrer equipped with a propeller 
blade. The blended mixture was cast into a 6".times.6".times.0.125 
(15.24.times.15.24.times.0.3175 cm) mold and cured at 120.degree. C. for 
17 hours in an air circulating oven. Elongation was determined using 
tensile bars die cut from the molded slabs using procedures described in 
ASTM D419. Three 20 mL scintillation vials were filled with 12 g each of 
the mixture and cured at 120.degree. C. for 17 hours in an air circulating 
oven. For hardness measurements three 20 mL scintillation vials were 
filled with 12 g each of a mixed formulation and cured at 120.degree. C. 
for 17 hours in an air circulating oven. The hardness was determined for 
each formulation sample using a Voland Texture Analyzer as above. The 
results are shown on Table 4. 
TABLE 4 
__________________________________________________________________________ 
Exam- 
Wt. DOP 
Wt. DTDP Wt. Cura- 
Wt. D11A 
Wt. D12 
Hard- 
Elonga- 
ple No. 
(g) (g) Curative 
tive (g) 
(g) (g) ness (g) 
tion (%) 
__________________________________________________________________________ 
4-1 150.0 
-- D400 3.36 24.00 6.00 45 400 
4-2 150.0 
-- D400 3.24 21.00 9.00 31 550 
4-3 150.0 
-- D400 3.12 15.00 12.00 
15 700 
4-4 150.0 
-- D400 3.10 15.00 15.00 
7 1000 
4-5 45.0 -- D400 3.00 12.00 18.00 
55 1050 
4-6 45.0 -- D400 2.85 9.00 21.00 
14 1550 
4-7 22.5 -- D2000 
4.07 7.50 7.50 200 -- 
4-8 22.5 -- D2000 
4.28 7.50 7.50 257 -- 
4-9 22.5 -- D2000 
4.50 7.50 7.50 236 -- 
4-10 
90.0 -- DDD 1.84 6.00 24.00 
136 -- 
4-11 
90.0 -- DDD 1.74 6.00 24.00 
156 -- 
4-12 
90.0 -- DDD 1.65 6.00 24.00 
200 -- 
4-13 
-- 65.0 D2000 
10.01 15.81 6.67 7 -- 
4-14 
-- 65.0 D2000 
10.41 15.53 6.66 19 -- 
4-15 
-- 65.0 D2000 
10.80 15.26 6.54 35 -- 
4-16 
-- 65.0 D2000 
11.17 15.00 6.43 40 -- 
4-17 
-- 65.0 D2000 
11.53 14.75 6.32 36 -- 
4-18 
-- 65.0 D2000 
11.88 14.50 6.21 25 -- 
4-19 
-- 81.7 D2000 
11.17 15.00 6.43 22 1250 
__________________________________________________________________________ 
EXAMPLE 4 
Using the procedure of Example 3, gels were prepared from a difunctional 
amine, 4,4'-diamino-3,3'-dimethyldicyclohexyl methane (DDD, equivalent 
weight 119) and various mixtures of a branched isocyanate terminated 
urethane polymer (Desmocap 11A, available from Mobay Corporation) which 
contains about 2.4% blocked isocyanate group and has an equivalent weight 
of about 1750 and a linear aromatic urethane polymer with ether groups 
(Desmocap 12 available from Mobay Corporation) which contains about 1.7% 
blocked isocyanate and has an equivalent weight of about 2470. These gels 
were prepared in the presence of various concentrations of dioctyl 
phthalate. The results are shown in Table 5. 
TABLE 5 
__________________________________________________________________________ 
Sample 
Ratio of 11A to 
Diluent concentration 
Approximate molecular 
Voland hardness 
No. 12 (Wt./Wt.) 
(%) weight between crosslinks 
(g) 
__________________________________________________________________________ 
5-1 1:1 75 7,000 456 
5-2 1:1 85 7,000 137 
5-3 1:1 90 7,000 34 
5-4 1:1 95 7,000 .about.2 
5-5 1:4 75 20,000 201 
5-6 1:4 85 20,000 71 
5-6 1:4 90 20,000 18 
5-8 1:4 95 20,000 &lt;5 
__________________________________________________________________________ 
EXAMPLE 5 
Using the general procedure of Example 1, gels were prepared from a variety 
of diamines and or triamines. The formulations used and the evaluation 
results are illustrated in Tables 6, 7 and 8. In Table 6, gel samples 6-1 
to 6-12 illustrate the gel properties obtained using Therminol 66 as the 
diluent and varying the polyurea concentration. Gel sample 6-13 omits the 
Jeffamine D2000 but is otherwise similar. In Table 7 gel samples 7-1 and 
7-2 show gels made using mixtures of Shellflex 371 and Santicizer 141 or 
DEP as diluent. Gel samples 7-3 to 7-7 show how gel properties vary with 
the concentration of the polyurea. In Table 8, a variety of diluents have 
been used to prepare the gels. Gel samples 8-5 to 8-8 show how the gel 
properties at 20% polymer loading vary using HB-40 as diluent and 
various-triamine ratios. Gel samples 8-9 uses a polyol (PPG-1025) as well 
as an amine to obtain a polyurea gel in a polyol diluent. In sample 8-14 a 
stabilizer (Irganox 1090 from Ciba Geigy) is added to the composition used 
to prepare the gel. Gel samples 8-20 to 8-23 show how the diluent mixture 
may be varied to alter the solubility parameter of the gel. 
TABLE 6 
__________________________________________________________________________ 
Exam- 
Isocya- 
Amine 
Amine 
Diluent Ther- 
Gel Time 
Hard- 
Stress Relax- 
Tack 
ple No. 
nate DDI 
T5000 
D2000 
minol 66 
(sec) 
ness (g) 
ation (%) 
(g) 
__________________________________________________________________________ 
6-1 2.22 6.00 
4.00 
48.88 240 6 53.3 17.0 
6-2 2.06 7.00 
3.00 
28.24 205 19 81.0 14.0 
6-3 1.91 8.00 
2.00 
47.64 175 37 91.4 13.0 
6-4 2.22 6.00 
4.00 
36.66 105 14 64.8 25.2 
6-5 2.06 7.00 
3.00 
36.18 85 22 73.1 27.8 
6-6 1.91 8.00 
2.00 
35.72 70 54 91.4 14.0 
6-7 2.30 5.50 
4.50 
28.70 65 7 32.9 28.5 
6-8 2.14 6.50 
3.50 
28.32 55 26 67.2 38.5 
6-9 1.99 7.50 
2.50 
27.98 45 46 80.1 37.6 
6-10 
2.38 5.00 
5.00 
22.98 55 13 31.6 32.5 
6-11 
2.22 6.00 
4.00 
22.70 50 21 47.2 36.0 
6-12 
2.06 7.00 
3.00 
22.40 40 36 61.6 34.5 
6-13 
1.60 10.00 
-- 46.40 90 82 -- -- 
__________________________________________________________________________ 
TABLE 7 
__________________________________________________________________________ 
Isocyanate 
Amine Gel Time 
Hardness 
Sample 
DDI T5000 
Diluent 
Other (sec) 
(g) Tack (g) 
__________________________________________________________________________ 
7-1 1.45 10.00 
22.90.sup.b 
22.90.sup.d 
25 25 -- 
7-2 1.45 10.00 
22.90.sup.b 
22.90.sup.e 
120 21 -- 
DBP Concn.* (%) 
7-3 2.01 11.74 
41.24 
25.00 25 130 0.0 
7-4 1.61 9.39 
44.00 
20.00 30 92 0.0 
7-5 1.20 7.04 
46.75 
15.00 75 46 0.0 
7-6 1.01 5.87 
48.12 
12.50 95 21 0.0 
7-7 0.81 4.70 
49.50 
10.00 180 14 1.0 
__________________________________________________________________________ 
Notes on Table 7: 
.sup.b Shellflex 371; 
.sup.d Santicizer 141; 
.sup.e DEP; 
*concentration of polyurea in gel composition. 
TABLE 8 
__________________________________________________________________________ 
Isocya- Diluent Gel Hard- 
Stress 
Sample 
nate 
Amine 
Amine 
as Other 
Time 
ness 
Relaxa- 
Tack 
No. DDI T3000 
D2000 
indicated 
Material 
(sec) 
(g) tion (%) 
(g) 
__________________________________________________________________________ 
8-1 1.90 
7.50 
-- 35.70.sup.h 
-- 50 23 17.5 7.5 
8-2 1.45 
10.00 
-- 46.00.sup.d 
-- 35 58 2.0 1.0 
8-3 1.45 
10.00 
-- 46.00.sup.c 
-- 45 49 5.0 3.0 
8-4 1.45 
10.00 
-- 46.00.sup.f 
-- 110 39 3.0 0.0 
8-5 1.96 
7.00 
3.00 
47.84.sup.f 
-- 240 7 37.8 11.0 
8-6 1.79 
8.00 
2.00 
47.16.sup.f 
-- 240 19 12.5 9.2 
8-7 1.61 
9.00 
1.00 
46.44.sup.f 
-- 200 17 10.0 16.0 
8-8 1.45 
10.00 
0.00 
45.80.sup.f 
-- 115 50 2.0 5.0 
8-9 1.56 
10.00 
-- 46.24.sup.j 
-- 30 36 9.0 4.5 
8-10 
1.45 
10.00 
-- 45.76.sup.f 
-- 45 50 4.5 3.5 
8-11 
1.46 
10.00 
-- 45.76.sup.k 
-- 35 63 1.3 1.2 
8-12 
1.52 
7.5 2.5.sup.i 
34.65.sup.h 
-- 50 24 18.5 6.5 
8-13 
0.83 
6.78 
-- 20.04.sup.l 
-- 90 34 5.9 4.0 
8-14 
1.76 
7.1 3.55.sup.i 
37.24.sup.g 
0.80.sup.m 
43 -- 1.0 4.0 
8-15 
1.53 
5.00 
-- 36.97.sup.g 
-- 25 88 7.0 0.0 
8-16 
2.37 
3.75 
3.75 
48.60.sup.e 
0.55.sup.m 
40 80* 
-- -- 
8-17 
2.37 
3.75 
3.75 
24.30.sup.e 
24.30.sup.n 
100 32* 
-- -- 
8-18 
2.37 
3.75 
3.75 
24.30.sup.e 
24.30.sup.j 
40 60* 
-- -- 
8-19 
2.37 
3.75 
3.75 
48.60.sup.e 
-- 35 94* 
-- -- 
8-20 
2.37 
3.75 
3.75 
48.60.sup.n 
-- &gt;15 2 -- -- 
8-21 
2.25 
3.75 
3.75 
24.00.sup.g 
24.00.sup.p 
90 23 -- -- 
8-22 
2.25 
3.75 
3.75 
12.00.sup.g 
36.00.sup.p 
80 21 -- -- 
8-23 
2.25 
3.75 
3.75 
0.00 48.00.sup.p 
75 36 2.8 -- 
__________________________________________________________________________ 
Notes on Table 8: 
.sup.c Santicizer 154; 
.sup.d Santicizer 141; 
.sup.e DEP; 
.sup.f HB40; 
.sup.g DBP; 
.sup.h Santicizer 160; 
.sup.i D4000; 
.sup.j PPG1025; 
.sup.k Phosphlex 362; 
.sup.l Jayflex DTDP; 
.sup.m Antioxidant; 
.sup.n Ketjenflex 8; 
.sup.p TOTM; 
*at 6 mm indentation. 
EXAMPLE 6 
Using the procedure of Example 1 gels were prepared using HB-40, Santicizer 
154 and mixtures thereof as diluent. The formulations used 1.5 g of DDI 
and 10 g of Jeffamine T-5000 and the diluents were used at the 
concentrations shown in Table 9. The electrical properties of the gels 
produced thereby are also shown in Table 9. 
TABLE 9 
__________________________________________________________________________ 
Ratio of HB-40 to 
Dielectric constant 
Dielectric constant 
Volume resistivity of 
Sample No. 
S-154 of diluent 
of gel gel (ohm-cm) 
__________________________________________________________________________ 
9-1 100 to 0 2.54 3.87 2.7 .times. 10.sup.11 
9-2 95 to 5 2.78 3.75 3.0 .times. 10.sup.11 
9-3 75 to 25 3.73 4.51 4.9 .times. 10.sup.10 
9-4 50 to 50 4.93 4.49 1.1 .times. 10.sup.10 
9-5 0 to 100 
7.33 8.59 8.3 .times. 10.sup.8 
__________________________________________________________________________ 
EXAMPLE 7 
Using the procedure of Example 1 gels were prepared from a multifunctional 
polyisocyanate (Desmodur N-3300 supplied by Mobay Chemicals). This 
polyisocyanate is understood to be prepared by the reaction of excess 
hexamethylene di-isocyanate with a mixture of di-and triamines. The gels 
were prepared using the ingredients listed in Table 10. Properties of 
these gels are shown in Table 11. 
TABLE 10 
__________________________________________________________________________ 
Polymer con- 
Sample No. 
Amine used 
Chemical name or type 
Supplier 
Diluent 
centration (%) 
__________________________________________________________________________ 
10-1 Poly BD AT-C 
Amine terminated poly- 
Arco a, b 15 
butadiene 
10-2 Hycar ATBN 
Amine terminated poly- 
Goodrich 
c 7 
1300 .times. 42 
butadiene/acrylonitrile 
liquid rubber 
10-3 HC1101 Polyetherdiamine 
3M a, 5 
10-4 PTHF-2100 
Bis(3-aminopropyl)poly- 
BASF a 12.5 
tetrahydrofuran (MW .about. 
2100) 
10-5 Jeffamine D-2000 Texaco 
a, r 15 
10-6 Jeffamine T-5000 Texaco 
a, r 25 
__________________________________________________________________________ 
Notes on Table 10: 
a Therminol 60; 
b Shellflex 371; 
c Santicizer 154; 
r Therminol 66. 
TABLE 11 
______________________________________ 
Sample Gelling Hardness Stress Re- 
Tack 
No. Time (sec) (g) laxation (%) 
(g) 
______________________________________ 
11-1 75 71 1 1.5 
11-2 5 68 -- -- 
11-3 45 38 -- -- 
11-4 15 176 -- -- 
11-5 18 152 -- -- 
11-6 &lt;10 400 -- -- 
______________________________________ 
EXAMPLE 8 
In an experiment to demonstrate the improved heat aging performance of 
certain polyurea gels when compared with similar polyurethane gels, gel 
formulations were prepared, using the same diluent, to have similar 
polymer networks and crosslink densities. Two polyurea gels which are 
examples of this invention were compared with two polyurethane gels which 
are not examples of this invention. The formulations used and the Voland 
hardness of samples of each formulation as cured and after 7 days in an 
oven maintained at 100.degree. C. are shown in Table 12. Table 12 shows 
that the polyurethane gels had decreased in hardness after 7 days at 
100.degree. C. by over 75 and 85% respectively but the polyurea gels had 
decreased in hardness by only 39 and 11% after the same aging. 
In a separate experiment, stabilized gels of the invention which were 
isocyanate rich, on stoichiometry and amine rich but which were otherwise 
identical were prepared. The gels were exposed to oxygen at 225.degree. C. 
in a DSC and the time which elapsed before rapid absorption of oxygen was 
measured to be &lt;14.5, 16.1 and 19.6 minutes respectively. Thus the amine 
rich gels show much greater oxidative stability than do the other gels. 
TABLE 12 
__________________________________________________________________________ 
Dimer di- 
Trifunctional amine 
Difunctional amine or 
Ditridecyl 
isocyanate 
or glycol glycol phthalate 
Voland hardness 
(g) Name (g) Name (g) (g) As cured (g) 
Aged (g) 
__________________________________________________________________________ 
0.93 T-5000 
6.57 
-- -- 17.5 115 70 
1.05 T-5000 
5.16 
D-2000 1.29 
17.5 18 16 
1.67 PPG-4000 
5.85 
-- -- 17.5 125 30* 
1.85 PPG-4000 
4.52 
PPG-2000 
1.11 
17.5 29 4* 
__________________________________________________________________________ 
Notes to Table 12: 
*These are not examples of the invention. 
EXAMPLE 9 
Kits for preparing polyurea gels were prepared from the ingredients listed 
in Table 13 (all amount are parts by weight). For each application Parts A 
and B were placed in disposable cartridges and dispensed through a static 
mixer/dispenser into an end of a telephone cable or high voltage cable 
where, for example a splice has been made and cured to form a water block. 
The gel time for the first formulation was about three minutes and the gel 
had a hardness of 35 g and a tack of 4 to 5 g with a stress relaxation of 
1.5%. The gel time for the second formulation was also about three minutes 
and the gel had a hardness of 29 g, a tack of 7.5 g and a stress 
relaxation of 8.5%. The third formulation had a gel time of about 2.5 
minutes, a hardness of 28 g, a tack of 25 g and exhibited a stress 
relaxation of 7.0%. This last formulation is particularly suited for use 
as a filling in, for example, protective articles such as are disclosed in 
U.S. Pat. Nos. 4,600,261; 4,634,207; 4,864,725; 4,865,905; 4,610,738 and 
4,622,692; and in telephone terminal blocks and wire and cable splice 
enclosures such as are described in U.S. Pat. Nos. 4,846,721; 4,859,809; 
and 4,880,676 and in published patent applications EP 0,298,713 and WO 
89/08338. The entire disclosures of all of the above patents and patent 
applications are incorporated by reference herein for all purposes. 
TABLE 13 
______________________________________ 
Tele- High 
phone voltage For use in sealing 
Application: 
cable gel 
cable gel caps and covers 
______________________________________ 
Part A 
Dimer di-isocyanate: 
1.91 1.99 1.99 
Therminol 66: 
27.87 27.84 27.98 
Irganox 1010 : 
0.30 0.60 0.60 
Part B 
Jeffamine T-5000: 
8.00 7.50 7.50 
Jeffamine D-2000: 
2.00 2.50 2.50 
Therminol 66: 
19.78 20.13 19.97 
Naugard 445*: 
0.30 -- -- 
Tinuvin 765**: 
-- 0.30 0.30 
______________________________________ 
: tetrakis[methylene 3(3',5ditert-butyl-4hydroxyphenyl)propionate]methan 
*: 4,4bis(.alpha.,.alpha. dimethylbenzyl) diphenylamine 
**: bis(1,2,2,6,6pentamethyl-4-piperidinyl) sebacate 
EXAMPLE 10 
This example shows that soft gels of the invention can be prepared using 
diluent contents less than 40%. Gels were prepared using the procedure of 
Example 1. The formulations used and properties of the resultant gels are 
shown in Table 14. These gels have particularly high tack values. 
TABLE 14 
__________________________________________________________________________ 
Polymer 
Isocya- Diluent 
Gel Hard- 
Stress 
Sam- 
content % 
nate Amine 
Amine 
Thermi- 
Time 
ness 
Relaxa- 
ple No. 
w/w TXMDI 
T5000 
D2000 
nol 60 
(sec) 
(g) tion (%) 
Tack (g) 
__________________________________________________________________________ 
10-1 
50 2.19 11.40 
11.41 
25.00 
.about.75 
9/56 
36 50 
10-2 
60 2.62 13.69 
13.69 
20.00 
30 8/96 
40 120 
10-3 
70 3.06 15.96 
15.96 
15.00 
20 20/167 
43 135 
__________________________________________________________________________ 
*2 hr cure at room temperature/after 87 hr at 60.degree. C. 
EXAMPLE 11 
Polyurea gels of the invention were compared with polyurethane gels, not of 
the invention, to assess their compatibility with plasticized polyvinyl 
chloride containing about 22% dioctyl phthalate as plasticizer. The 
formulations (in parts by weight) of the polyurea and polyurethane are 
given below in Table 15. 
Flat PVC sheets 25-30 mils (0.63-0.76 mm) thick were placed between 0.25 in 
(6.3 mm) thick sheets of the gels and the assemblies maintained at 
80.degree. C. for 7 days. The changes in weight and the changes in tensile 
strength and rupture elongation of the PVC sheet were then measured. The 
PVC sheet placed in contact with polyurea gel gained weight by 3% while 
its tensile strength was almost unchanged (increased 1.5%) and its rupture 
elongation decreased by 20%. The PVC sheet placed in contact with 
polyurethane gel decreased in weight by 13.6% while its tensile strength 
increased by 18.8% and its rupture elongation decreased by 46%. 
TABLE 15 
______________________________________ 
Polyurea gel 
Polyurethane gel* 
______________________________________ 
Part A 
DDI 1.96 7.31 
Diluent: 
Therminol 66 27.94 -- 
Shellflex 371 -- 42 
Stabilizer 0.3 1.3 
Part B 
Jeffamine T-5000 
8.00 -- 
Jeffamine D2000 2.00 -- 
Polybutadiene -- 26.96 
Therminol 66 19.9 -- 
Shellflex 371 -- 22.57 
Stabilizer 0.3 0.04 
n-Octyl-n-decyl trimellitate 
-- 50 
______________________________________ 
EXAMPLE 12 
A polyurea gel was prepared using the procedure of Example 1 from the 
following ingredients: 
______________________________________ 
Part A: Parts by weight 
Part B: Parts by weight 
______________________________________ 
DDI 2.90 Sylvamide 125 
2.00 
Therminol 60 
11.25 Therminol 60 
11.25 
Ketjenflex 8 
11.25 Ketjenflex 8 
11.25 
______________________________________ 
Silvamide 125 is an amide rich polyamide available from Sylvachem 
Corporation. The gel had a hardness of 34 g, a stress relaxation of 14.5% 
and a tack of 1 g. 
FIG. 1 illustrates how the hardness of the cured polyurea gels of Example 1 
varies with polymer concentration and diluent level. FIG. 2 illustrates 
how the hardness of these cured gels varies with the ratio of diamine to 
triamine and FIG. 3 illustrates how the gel time varies with polymer 
concentration and diamine to triamine ratio. 
EXAMPLE 13 
This example illustrates the preparation of high-polymer content gels of 
this invention made from a ketone-blocked amine. 
The part (B) (amine) polyurea gel masterbatches containing Jeffamine 
T-5000, 2-decanone, and Therminol 66 extender fluid were prepared by 
weighing the materials into plastic beakers. These solutions were mixed, 
covered with aluminum foil, and placed in a 60.degree. C. oven for 16 hr 
to allow the ketimine to form. After removal from the oven the solutions 
were allowed to cool to room temperature for two hours. A part (A) 
masterbatch (dimer di-isocyanate) was prepared (the same part (A) 
masterbatch was used for all formulations) by weighting out the 
components, mixing, and pouring into separate beakers. The part (A)'s were 
then mixed with the part (B)'s. The mixtures were allowed to stand at room 
temperature and checked periodically for gelation. Hardness of the gels 
was measured using a Voland Texture Analyzer with a 1/4" ball probe 
inserted 4 mm at 0.2 mm/sec. The results are provided in Table 16: 
TABLE 16 
______________________________________ 
Per Cent Polymer 
20 30 45 60 
______________________________________ 
Part A 
DDI 1410 1.50 1.50 1.50 1.50 
Therminol 60 4.00 4.00 4.00 4.00 
TOTAL WEIGHT 5.50 5.50 5.50 5.50 
Part B 
Jeffamine T-5000 
10.00 10.00 10.00 10.00 
Therminol 66 40.90 21.73 7.96 2.57 
2-Decanone 1.10 1.10 1.10 1.10 
TOTAL WEIGHT 52.00 32.83 19.06 13.67 
Gel time (min) 
.about.60 
.about.60 
.about.60 
.about.60 
Hardness (g) 
6 hr cure time 
41 78 136 243 
24 hr cure time 
69 152 325 589 
7 day cure time 
76 175 427 N.D. 
______________________________________ 
N.D. -- not determined 
EXAMPLE 14 
This example illustrates the blocking of amines with an aldehyde, in gels 
of this invention. 
Part (B) (amine) masterbatches and a part (A) (isocyanate) masterbatch were 
prepared from Desmodur N-3300, Jeffamine D-4000, dodecyl aldehyde, and 
Therminol 60 extender fluid generally by the procedure of the immediately 
previously example. A series of gels containing 20% polymer was prepared 
and analyzed as before. The results are provided in Table 17: 
TABLE 17 
______________________________________ 
Sample Number 
1 2 3 4 5 6 
______________________________________ 
Part A 
Desmodur 1.00 1.00 1.00 1.00 1.00 1.00 
N-3300 
Therminol 60 
29.56 29.56 29.56 29.56 29.56 29.56 
TOTAL 30.56 30.56 30.56 30.56 30.56 30.56 
WEIGHT 
Part B 
Jeffamine 
10.00 10.00 10.00 10.00 10.00 10.00 
D-4000 
Therminol 60 
20.56 20.56 20.56 20.56 20.56 20.56 
Dodecyl 0.15 0.30 0.45 0.60 0.75 0.85 
aldehyde 
TOTAL 30.71 30.86 31.01 31.16 31.31 31.41 
WEIGHT 
Gel time 1 6 70 150 300 420 
(min) 
Hardness (g) 
24 hr cure 
140 102 69 35 16 11 
time 
10 day cure 
158 135 112 87 64 48 
time 
______________________________________