U.S. patent application number 08/930403 was filed with the patent office on 2001-11-01 for polydiorganosiloxane oligourea segmented copolymers and a process for making same.
Invention is credited to EVERAERTS, ALBERT I., LEIR, CHARLES M., MAZUREK, MIECZYSLAW H., NELSON, CONSTANCE J., ROMANKO, WALTER R., SHERMAN, AUDREY A.
Application Number | 20010037008 08/930403 |
Document ID | / |
Family ID | 25459297 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010037008 |
Kind Code |
A1 |
SHERMAN, AUDREY A ; et
al. |
November 1, 2001 |
POLYDIORGANOSILOXANE OLIGOUREA SEGMENTED COPOLYMERS AND A PROCESS
FOR MAKING SAME
Abstract
The present invention provides polydiorganosiloxane oligourea
segmented copolymers. The copolymers contain soft
polydiorganosiloxane units, hard segments that are diisocyanate
residues, the polydiorganosiloxane units and diisocyanate residues
being connected by urea linkages, and terminal groups that are
nonreactive, reactive under free radical or moisture cure
conditions, or amines. The invention also provides methods of
preparing the copolymers.
Inventors: |
SHERMAN, AUDREY A; (ST.
PAUL, MN) ; ROMANKO, WALTER R.; (AUSTIN, TX) ;
EVERAERTS, ALBERT I.; (OAKDALE, MN) ; LEIR, CHARLES
M.; (FALCON HEIGHTS, MN) ; MAZUREK, MIECZYSLAW
H.; (ROSEVILLE, MN) ; NELSON, CONSTANCE J.;
(WOODBURY, MN) |
Correspondence
Address: |
MICHEAL SHERRIL LAW OFFICES
4756 BANNING AVENUE
SUITE 200
WITE BEAR LAKE
MN
55110
|
Family ID: |
25459297 |
Appl. No.: |
08/930403 |
Filed: |
September 26, 1997 |
PCT Filed: |
April 25, 1996 |
PCT NO: |
PCT/US96/05870 |
Current U.S.
Class: |
528/28 |
Current CPC
Class: |
C08G 77/452
20130101 |
Class at
Publication: |
528/28 |
International
Class: |
C08G 077/04 |
Claims
What is claimed is:
1. Polydiorganosiloxane oligourea segmented copolymers comprising
soft polydiorganosiloxane units, hard polyisocyanate residue units,
wherein the polyisocyanate residue is the polyisocyanate minus the
--NCO groups, optionally, soft and/or hard organic polyamine units,
wherein residues of the isocyanates amine units are connected by
urea linkages, and terminal groups, wherein the terminals groups
are non-functional endcapping groups or functional endcapping
groups.
2. Polydiorganosiloxane oligourea segmented copolymers according to
claim 1 represented by the repeating unit: 9wherein each Z is a
polyvalent radical selected from arylene radicals and aralkylene
radicals having from about 6 to 20 carbon atoms, alkylene and
cycloalkylene radicals having from about 6 to 20 carbon atoms; each
R is a moiety independently selected from alkyl moieties preferably
having about 1 to 12 carbon atoms and may be substituted with, for
example, trifluoroalkyl or vinyl groups, a vinyl radical or higher
alkenyl radical preferably represented by the formula
-R.sup.2(CH.sub.2).sub.aCH.dbd.CH.sub.2 wherein R.sup.2 is
--(CH.sub.2).sub.b--or --(CH.sub.2).sub.cCH.dbd.CH-- and a is 1, 2
or 3; b is 0, 3 or 6; and c is 3, 4 or 5; a cycloalkyl moiety
having about 6 to 12 carbon atoms and may be substituted with
alkyl, fluoroalkyl, and vinyl groups, or an aryl moiety preferably
having about 6 to 20 carbon atoms and that may be substituted with
alkyl, cycloalkyl, fluoroalkyl and vinyl groups or R is a
perfluoroalkyl group, a fluorine-containing group, or a
perfluoroether-containing group; each Y is a polyvalent moiety
independently selected from an alkylene radical having 1 to 10
carbon atoms, aralkylene radical and arylene radical, having 6 to
20 carbon atoms; each D is independently selected from hydrogen,
alkyl radicals having 1 to 10 carbon atoms, phenyl, and a radical
that completes a ring structure including B or Y to form a
heterocycle having about 6 to 20 carbon atoms; each A is
independently --B--, or --YSi(R).sub.2(OSi(R).sub- .2).sub.pY-- or
mixtures thereof; B is a polyvalent radical selected from the group
consisting of alkylene, aralkylene, cycloalkylene, phenylene,
polyalkylene oxide and copolymers thereof, and mixtures thereof; m
is a number that is 0 to about 8; b, c, d and n are 0 or 1, with
the provisos that, b+d=1 and e+n=1; p is about 10 or larger; q is
about 10 or larger; t is a number which is 0 to about 8; s is 0 or
1; and each X is independently: (a) a moiety represented by 10
wherein D is defined as above; (b) a moiety represented by 11 where
each of D, and Z are defined as above, (c) a monovalent moiety that
is not reactive under moisture curing or free radical curing
conditions and that can be the same or different and that are alkyl
moieties preferably having about 1 to 20 carbon atoms and that can
be substituted with, for example, trifluoroalkyl groups, or aryl
moieties preferably having about 6 to 20 carbon atoms and that may
be substituted with alkyl, aryl, and substituted aryl groups; (d) a
moiety represented by 12 where each of Z, and D are defined as
above, K is independently (i) a moiety that is not reactive under
moisture curing or free radical curing conditions and that can be
the same or different selected from the group consisting of alkyl,
substituted alkyl, aryl, and substituted aryl; (ii) a free
radically curable end group, such as, acrylate, methacrylate,
acrylamido, methacrylamido and vinyl groups; (iii) a moisture
curable group such as, alkoxysilane and oxime silane groups; and
(e) a moiety represented by 13 wherein D, Y and K are defined as
above.
3. The polydiorganosiloxane oligourea copolymer of claim 2 wherein
at least 50% of the R moieties are methyl radicals with the balance
being monovalent alkyl or substituted alkyl radicals, alkenylene
radicals, phenyl radicals, or substituted phenyl radicals.
4. The polydiorganosiloxane oligourea segmented copolymer.
according to claim 2, wherein Z is 2,6-tolylene,
4,4'-methylenediphenylene, 3,3'-dimethoxy-4,4'-biphenylene,
tetramethyl-m-xylylene, 4,4'-methylenedicyclohexylene,
3,5,5-trimethyl-3-methylenecyclohexylene, 2,2,4-trimethylhexylene,
1,6-hexamethylene, 1,4-cyclohexylene, and mixtures thereof.
5. The polydiorganosiloxane oligourea segmented copolymer according
to claim 4, wherein Z is tetramethyl-m-xylylene.
6. A polydiorganosiloxane oligourea segmented copolymer comprising
the reaction product of: (a) at least one polyisocyanate; (b) an
endcapping agent having a terminal selected from
polydiorganosiloxane monoamines and non-siloxane containing
endcapping agents having a terminal portion reactive with an amine
or isocyanate and a terminal portion that is non-functional or that
can react under moisture-cure or free-radical conditions, with the
provisos (1) that if no polydiorganosiloxane monoamine is present,
then at least one polyamine is present, wherein polyamine comprises
at least one polydiorganosiloxane diamine or a mixture of at least
one polydiorganosiloxane diamine and at least one organic
polyamine, (2) if only polyisocyanate and polyamine are present,
the molar ratio of isocyanate to amine is <0.9:1 or >1.1:1,
and (3) when polydiorganosiloxane monoamine and diamine are
present, the ratio of total isocyanate available in the
polyisocyanate to the total amine available in the monoamine and
diamine less any amine end groups in the copolymer is about
1:1.
7. A process for preparing the copolymer according to claim 1
comprising the steps of: providing reactants, wherein the reactants
comprise (a) a polyisocyanate; (b) an endcapping agent selected
from polydiorganosiloxane monoamines and non-siloxane containing
endcapping agents having a terminal portion reactive with an amine
or isocyanate and a terminal portion that is non-functional or that
can react under moisture-cure or free-radical conditions; with the
provisos (1) that if no polydioganosiloxane monoamine is present,
then at least one polyamine is present, wherein polyamine comprises
at least one polydiorganosiloxane diamine or mixtures of at least
one polydiorganosilxane diamine and at least one organic polyamine,
(2) if only polyisocyanate and polyamine are present, the molar
ratio of isocyanate to amine is <0.9:1 or >1.1:1, and (3)
when polydiorganosiloxane monoamine and diamine are present, the
ratio of total isocyanate available in the polyisocyanate to the
total amine available in the monoamine and diamine less any amine
end groups in the copolymer is about 1:1; and (c) solvent to a
reactor; mixing the reactants in the reactor; allowing the
reactants to react to form a polydiorganosiloxane oligourea
segmented copolymer with an average degree of oligomerization of 2
to 12; and conveying the oligomer from the reactor.
8. An essentially solventless process for preparing the copolymer
of claim 1 comprising the steps of: continuously providing (a) a
polyisocyanate; (b) an endcapping agent selected from
polydiorganosiloxane monoamines and non-siloxane containing
endcapping agents having a terminal portion reactive with an amine
or isocyanate and a terminal portion that is non-functional or that
can react under moisture-cure or free-radical conditions; with the
provisos (1) that if no polydiorganosiloxane monoamine is present,
then at least one polyamine is present, wherein polyamine comprises
at least one polydiorganosiloxane diamine or a mixture of at least
one polydiorganosiloxane diamine and at least one organic
polyamine, (2) if only polyisocyanate and polyamine are present,
the molar ratio of isocyanate to amine is <0.9:1 or >1.1:1,
and (3) when polydioganosiloxane monoamine and diamine are present,
the ratio of total isocyanate available in the polyisocyanate to
the total amine available in the monoamine and diamine less any
amine end groups in the copolymer is about 1:1, to a reactor under
substantially solventless conditions; mixing the reactants in the
reactor under the substantially solventless conditions; allowing
the reactants to react to form a polydiorganosiloxane oligourea
segmented copolymer with a average degree of oligomerization of 2
to 12; and conveying the oligomer from the reactor.
Description
FIELD OF THE INVENTION
[0001] This invention relates to polydiorganosiloxane oligourea
segmented copolymers and a process for making same.
BACKGROUND OF THE INVENTION
[0002] Polydiorganosiloxane polymers have unique properties derived
mainly from the physical and chemical characteristics of the
siloxane bond. Typically, the outstanding properties of
polydiorganosiloxane polymers include resistance to ultraviolet
light, extremely low glass transition temperature, good thermal and
oxidative stability, good permeability to many gases, very low
surface energy, low index of refraction, good hydrophobicity, and
good dielectric properties. They also have very good
biocompatability and are of great interest as biomaterials that can
be used in the body in the presence of blood. Polydiorganosiloxane
elastomers have been widely used because of these many excellent
properties. But, their limited tear resistance and poor resistance
to low polarity solvents have made them unsuitable in many other
applications.
[0003] Elastomers possess the ability to recover their initial
shape from deformation produced by an imposed force. Traditional
polydiorganosiloxanes show elastomeric behavior only when they are
chemically or physically crosslinked. Even extremely high molecular
weight polydiorganosiloxane gums (greater than 500,000 grams per
mole) exhibit cold flow when uncrosslinked. However, chemical
crosslinking results in polymers with poor mechanical properties
relative to other organic materials. Thus, to be useful in most
commercial applications, traditional polydiorganosiloxanes must be
further filled with up to 50 weight percent fillers such as finely
divided high surface area silica, fumed silica, titanium dioxide,
alumina, zirconia, pigment-grade oxides, carbon blacks, graphite,
metal powders, clays, calcium carbonates, silicates, aluminates,
fibrous fillers, and hollow glass or plastic microspheres,
depending on the desired properties, for example, to maintain their
mechanical strength and reduce swelling in solvents. Since
polydiorganosiloxanes do not lose their mechanical strength as
abruptly as other organic materials at elevated temperatures, they
find particular use in high temperature applications.
[0004] For many uses such as in insulated wire, rods, channels,
tubing, and similar products, polydiorganosiloxane compounds are
extruded in standard rubber extrusion equipment. The extruded
material must immediately be heated to set the form. Usually,
hot-air vulcanization at 300-450.degree. C. or steam at 0.28-0.70
MPa (40-100 psi) for several minutes is needed. Final properties
can be developed by oven curing or by continuous steam
vulcanization.
[0005] For many other uses such as in elastomers, caulking,
gaskets, sealants, and release coatings, polydiorganosiloxane
compounds are applied as liquids or deformable semi-solids at room
temperature and require intimate mixing if two part systems are
used. Final properties are developed after lengthy cure times and
are generally inferior. Often a delay occurs before the next
sequence in manufacture or repair can proceed.
[0006] In recent years, free radically cured and moisture cured
liquid polydiorganosiloxane compositions have been disclosed that
cure rapidly and completely under exposure to radiation or
mnoderately elevated temperatures with excellent properties. Thus,
subsequent manufacturing or repair steps are often delayed until
some degree of curing occurs. Also, thick constructions cannot be
made without temporary support until curing is accomplished and
irregularly shaped surfaces can be difficult to coat adequately.
Therefore, there is still a need for polydiorganosiloxane
compositions with green strength, i.e., strength in the uncured
state, and controlled flow properties.
[0007] Silicone-based release coatings have been used commercially
for some time, predominantly in such applications as release liners
for adhesives. Generally, these materials are coated from solvent
or a carrier and thermally crosslinked at high temperatures.
Recently, silicone release technologies have been disclosed that
include addition cure, cationic cure, radiation cure, and moisture
cure of monomer, oligomer or polymer systems as well as
silicone-containing block copolymers that do not require curing.
Some of these systems can be coated without solvent, e.g., by roll
coating. Others can be coated from organic solvents or water. There
is still a need for a silicone-based coating with controlled flow
properties and good green strength while retaining the desirable
release performance features of the previously mentioned
materials.
[0008] Physically crosslinked polydiorganosiloxane polyurea
segmented copolymers, that may contain blocks other than
polydiorganosiloxane or urea, are elastomers that are synthesized
in and coated out of solvent. These copolymers have some potential
process economy advantages because their synthesis reaction is
rapid, requires no catalyst, and produces no by-products.
[0009] In producing polydiorganosiloxane polyurea segmented
copolymers, monofunctional reaction impurities in the
polydiorganosiloxane diamine precursor can inhibit the chain
extension reaction and limit the attainment of optimum molecular
weight and tensile strength of the polymer. Because the early
processes for making the polydiorganosiloxane diamines resulted in
increasing levels of monofunctional impurities with increasing
molecular weight, it was not possible to achieve elastomers having
satisfactory mechanical properties for most elastomer or adhesive
applications. More recently, processes have been developed that
produce low levels of impurities over a wide range of
polydiorganosiloxane diamine molecular weights. With these
processes polydiorganosiloxane polyurea segmented copolymers have
been obtained that have good mechanical properties through the use
of chain extenders to increase the non-silicone content. However,
these systems, with or without chain extender, do not flow at room
temperature.
[0010] Continuous melt polymerization processes have been used to
produce polyurethane elastomers and acrylate pressure-sensitive
adhesives. Polyetherimides, which can contain polydiorganosiloxane
segments, have also been produced in a continuous melt
polymerization process. Recently polyurethane resins have been
described that use polydiorganosiloxane urea segments to prevent
blocking of films formed from the resin. However, levels of
reactive polydiorganosiloxane in the compositions were small, for
example, less than 15 weight percent, and incomplete incorporation
of the polydiorganosiloxane into the backbone was not detrimental
since easy release was the intent. Unincorporated
polydiorganosiloxane oil can, however, act as a plasticizing agent
in elastomers to reduce tensile strength or detackify and reduce
shear properties of pressure-sensitive adhesives. This
unincorporated oil can also bloom to the surface of an elastomer or
adhesive and contaminate other surfaces with which it is in
contact.
SUMMARY OF THE INVENTION
[0011] Briefly, in one aspect of the present invention,
polydiorganosiloxane oligourea segmented copolymers are provided
wherein such copolymers comprise soft polydiorganosiloxane diamine
units, hard polyisocyanate residue units, wherein the
polyisocyanate residue is the polyisocyanate minus the --NCO
groups, optionally, soft and/or hard organic polyamine units,
wherein residues of the isocyanates amine units are connected by
urea linkages, and terminal groups, wherein the terminals groups
are non-functional endcapping groups or functional endcapping
groups.
[0012] The present invention further provides polydiorganosiloxane
oligourea segmented copolymer compositions comprising the reaction
product of
[0013] (a) at least one polyisocyanate;
[0014] (b) an endcapping agent having a terminal selected from
polydiorganosiloxane monoamines and non-siloxane containing
endcapping agents having a terminal portion reactive with an amine
or isocyanate and a terminal portion that is non-functional or that
can react under moisture-cure or free-radical conditions,
[0015] with the provisos (1) that if no polydiorganosiloxane
monoamine is present, then at least one polyamine is present,
wherein polyamine comprises at least one polydiorganosiloxane
diamine or a mixture of at least one polydiorganosiloxane diamine
and at least one organic polyamine, (2) if only polyisocyanate and
polyamine are present, the molar ratio of isocyanate to amine is
<0.9:1 or >1.1:1, and (3) when polydiorganosiloxane monoamine
and diamine are present, the ratio of total isocyanate available in
the polyisocyanate to the total amine available in the monoamine
and diamine less any amine end groups in the copolymer is about
1:1.
[0016] The polydiorganosiloxane oligourea segmented copolymer
compositions of the present invention can be represented by Formula
I. Anyone knowledgeable in the art would know that the
oligomerization process leads to randomization of the
polydiorganosiloxane diamine and organic polyamines along the back
one. This could lead to the organic polyamine reacting with the
endcapper. 1
[0017] wherein
[0018] each Z is a polyvalent radical selected from arylene
radicals and aralkylene radicals preferably having from about 6, to
20 carbon atoms, alkylene and cycloalkylene radicals preferably
having from about 6 to 20 carbon atoms, preferably Z is
2,6-tolylene, 4,4'-melthylenediphenylene,
3,3'-dimethoxy-4,4'-biphenylene, tetramethyl-m-xylylene,
4,4'-methylenedicyclohexylene,
3,5,5-trimethyl-3-methylenecyclohexylene, 2,2,4-trimethylhexylene,
1,6-hexamethylene, 1,4-cyclohexylene, and mixtures thereof;
[0019] each R is a moiety independently selected from alkyl
moieties preferably having about 1 to 12 carbon atoms and may be
substituted with, for example, trifluoroalkyl or vinyl groups, a
vinyl radical or higher alkenyl radical preferably represented by
the formula -R.sup.2(CH.sub.2).sub.aCH.dbd.CH.sub.2 wherein R.sup.2
is --(CH.sub.2).sub.b-- or --(CH.sub.2).sub.cCH.dbd.CH-- and a is
1, 2 or 3, b is 0, 3 or 6; and c is 3, 4 or 5; a cycloalkyl moiety
having about 6 to 12 carbon atoms and may be substituted with
alkyl, fluoroalkyl, and vinyl groups, or an aryl moiety preferably
having about 6 to 20 carbon atoms and that may be substituted with,
for example, alkyl, cycloalkyl, fluoroalkyl and vinyl groups or R
is a perfluoroalkyl group as described in U.S. Pat. No. 5,028,679,
wherein such description is incorporated herein by reference, a
fluorine-containing group as described in U.S. Pat. No. 5,236,997,
wherein such description is incorporated herein by reference or a
perfluoroether-containing group, as described in U.S. Pat. Nos.
4,900,474 and 5,118,775, wherein such descriptions are incorporated
herein by reference, preferably at least 50% of the R moieties are
methyl radicals with the balance being monovalent alkyl or
substituted alkyl radicals having 1 to 12 carbon atoms, vinylene
radicals, phenyl radicals, or substituted phenyl radicals;
[0020] each Y is a polyvalent moiety independently selected from an
alkylene radical preferably having 1 to 10 carbon atoms, aralkylene
radical and arylene radical, preferably having 6 to 20 carbon
atoms;
[0021] each D is independently selected from hydrogen, alkyl
radicals preferably having 1 to 10 carbon atoms, phenyl, and a
radical that completes a ring structure including B or Y to form a
heterocycle, preferably having about 6 to 20 carbon atoms;
[0022] each A is independently --B--, or
--YSi(R).sub.2(OSi(R).sub.2).sub.- pY-- or mixtures thereof;
[0023] B is a polyvalent radical selected from the group consisting
of alkylene, aralkylene, cycloalkylene, phenylene, polyalkylene
oxide, such as, polyethylene oxide, polypropylene oxide,
polytetramethylene oxide, and copolymers thereof, and mixtures
thereof;
[0024] m is a number that is 0 to about 8;
[0025] b, e, d and n are 0 or 1, with the provisos that, b+d=1 and
e+n=1;
[0026] p is about 10 or larger, preferably about 15 to 2000, more
preferably about 30 to 1500;
[0027] q is about 10 or larger, preferably about 15 to 2000, more
preferably about 30 to 1500; and
[0028] t is a number which is 0 to about 8;
[0029] s is 0 or 1; and
[0030] each X is independently:
[0031] (a) a moiety represented by 2
[0032] wherein D is defined as above;
[0033] (b) a moiety represented by 3
[0034] where each of D, and Z are defined as above,
[0035] (c) a monovalent moiety that is not reactive under moisture
curing or free radical curing conditions and that can be the same
or different and that are alkyl moieties preferably having about 1
to 20 carbon atoms and that can be substituted with, for example,
trifluoroalkyl groups, or aryl moieties preferably having about 6
to 20 carbon atoms and that may be substituted with, for example
alkyl, aryl, and substituted aryl groups and a particularly useful
embodiment when X is C, is when t=0 and m=0;
[0036] (d) a moiety represented by 4
[0037] where each of Z, and D are defined as above,
[0038] K is independently (i) a moiety that is not reactive under
moisture curing or free radical curing conditions and that can be
the same or different selected from the group consisting of alkyl,
substituted alkyl, aryl, and substituted aryl; (ii) a free
radically curable end group such as, for example acrylate,
methacrylate, acrylamido, methacrylamido and vinyl groups; (iii) a
moisture curable group such as, for example, alkoxysilane and oxime
silane groups, and
[0039] (e) a moiety represented by 5
[0040] wherein D, Y and K are defined as above.
[0041] In the use of polyisocyanates (Z is a radical having a
functionality greater than 2) and polyamines (B is a radical having
a functionality greater than 2), the structure of Formula I will be
modified to reflect branching at the polymer backbone.
[0042] The average degree of oligomerization refers to the size of
the resultant oligomer molecule and is determined from the number
average of the residue of amine-containing reactant molecules in
the oligomer. There are two ways of obtaining the desired degree of
oligomerization: (1) control the isocyanate to amine ratio to
obtain either isocyanate or amine endcapped oligomer (X=a or b),
and (2) judiciously select the amount of monoamine or
monoisocyanate endcapper with stoichiometric amounts of isocyanate
and amine (X=c, d, or e). The following table displays the mol
ratios of the various molecules necessary for building a molecule
with the desired endcapper X. For the use of polyamines and
polyisocyanates, the ratios may be adjusted accordingly.
1 X(a) X(b) X(c) X(d) X(e) Degree of t + m + 2 t + m + 2 t + m + 2
t + m + 4 t + m + 2 oligomeri- zation Polydi- t + m + 2 t + m + 2 t
+ m + 2 t + m + 2 t + m + 2 organo- siloxane diamine Diisocyanate t
+ m + 1 t + m + 3 t + m + 1 t + m + 3 t + m + 1 Polydi- -- -- 2 --
-- organo- siloxane monoamine Organic -- -- -- 2 -- monoamine
Monoiso- -- -- -- -- 2 cyanate
[0043] The polydiorganosiloxane oligourea segmented copolymers of
the present invention can be prepared to exhibit desired controlled
flow properties in the uncured state, being liquid or semi-solid at
ambient temperatures. The controlled flow properties of the
copolymer can be optimized by appropriate selection of the
polyisocyanate, the molecular weight of the polydiorganosiloxane
amine, the average degree of oligomerization, the organic polyamine
selected, and the nature of Z. Generally, the green strength of the
resultant polydiorganosiloxane polyurea segmented oligomer
increases with decreasing polydiorganosiloxane amine molecular
weight. The compositions of the present invention have an average
degree of oligomerization of between 2 and 12.
[0044] The polydiorganosiloxane oligourea segmented copolymers of
the present invention have diverse utility. The copolymers possess
the conventional excellent physical properties associated with
polysiloxanes of low glass transition temperature, high thermal and
oxidative stabilities, UV resistance, low surface energy and
hydrophobicity, good electrical properties and high permeability to
many gases.
[0045] When the polydiorganosiloxane oligourea segmented copolymers
are terminated with non-functional end groups, the resulting
copolymers possess the thermally reversible properties of a gel,
semisolid, or solid at room temperature and of a fluid at elevated
temperatures. Selected polydiorganosiloxane oligourea segmented
copolymers of the present invention have a surprisingly low melt
flow viscosity and abrupt solidification at a temperature below the
melt flow conditions. Additionally, these selected copolymers
exhibit ease of reprocessing without additional stabilizers that
make them suitable as thermally reversible encapsulants and potting
compounds or as caulking compounds where sharp or reversible
liquid/solid transitions are desired, for example, such as in
assembly line operations.
[0046] Advantageously, the selection of the terminal group used to
prepare the copolymers of the present invention can provide a
variety of materials having various properties. The terminal groups
of the copolymer can either be non-functional or functional. If the
terminal group is a functional end-capping group, the resultant
copolymers have a latent reactivity, such that these functional
end-capped copolymers can serve as prepolymer units, can be
crosslinked, can be cured, and the like.
[0047] When the polydiorganosiloxane oligourea segmented copolymers
of the present invention are terminated with reactive amine end
groups, they can be further reacted with multifunctional
isocyanates, multifunctional acrylates, multifunctional anhydrides,
or mixtures thereof to obtain various crosslinked branched, or
chain-extended materials.
[0048] When the polydiorganosiloxane oligourea segmented copolymers
of the present invention are terminated wvitlh reactive isocyanate
end groups, they can be further reacted with water, multifunctional
amines, multifunctional alcohols, multifunctional mercaptans, or
mixtures thereof to obtain various crosslinked branched, or
chain-extended materials.
[0049] Additionally, when the polydiorganosiloxane oligourea
segmented copolymers of the invention are terminated with a
chemically curable end group, the resulting green strength, that
is, strength prior to curing, is generally greater than that for
chemically crosslinkable silicone compositions known in the
art.
[0050] The polydiorganosiloxane oligourea segmented copolymers of
the present invention having free radically curable end groups can
be solution coated or hot melt coated easily without placirg
adverse stresses into the coating and can be formed into irregular
shapes that will hold their shape until they are thermally or
radiation cured. Such a feature makes them useful, for example, in
applications such as gaskets, sealants, and replicated surfaces and
coatings on easily deformable substrates.
[0051] The polydiorganosiloxane oligourea segmented copolymers of
the present invention having moisture curable end groups can be
solution coated or hot melt coated in a manner similar to the free
radically cured forms, or applied to a variety of irregular
substrates in situations that do not allow subsequent thermal or
radiation curing treatments or in which free radical reactions are
inhibited by the presence of oxygen. Such characteristics make them
useful, for example, in applications in the building construction
industry, such as caulking and sealants, and in areas where oxygen
inhibited radiation or thermal treatments are not preferred.
[0052] The polydiorganosiloxane oligourea segmented copolymers of
the present invention with both free radically curable end groups
and moisture curable end groups are useful, for example, in
situations where partial cure by one mechanism is desirable
followed by complete cure by another method. Areas where this
feature is useful include situations where a subsequent
manufacturing operation is desired and superior green strength is
beneficial, such as in assembly line operations.
[0053] The present invention further provides a solvent process and
a solventless process for producing the polydiorganosiloxane
oligourea segmented copolymers of the present invention.
[0054] The solvent process comprises the steps of
[0055] providing reactants, wherein the reactants comprise (a) a
polyisocyanate; (b) an endcapping agent selected from
polydiorganosiloxane monoamines and non-siloxane containing
endcapping agents having a terminal portion reactive with an amine
or isocyanate and a terminal portion that is non-functional or that
can react under moisture-cure or free-radical conditions; with the
provisos (1) that if no polydiorganosiloxane monoamine is present,
then at least one polyamine is present, wherein polyamine comprises
at least one polydiorganosiloxane diamine or mixtures of at least
one polydiorganosilxane diamine and at least one organic polyamine,
(2) if only polyisocyanate and polyamine are present, the molar
ratio of isocyanate to amine is <0.9:1 or >1.1:1, and (3)
when polydiorganosiloxane monoamine and diamine are present, the
ratio of total isocyanate available in the polyisocyanate to the
total amine available in the monoamine and diamine less any amine
end groups in the copolymer is about 1:1; and (c) solvent to a
reactor;
[0056] mixing the reactants in the reactor;
[0057] allowing the reactants to react to form a
polydiorganosiloxane oligourea segmented copolymer with an average
degree of oligomerization of 2 to 12; and
[0058] conveying the oligomer from the reactor.
[0059] The solventless process comprises the steps of:
[0060] continuously providing (a) a polyisocyanate; (b) an
endcapping agent selected from polydiorganosiloxane monoamines and
non-siloxane containing endcapping agents having a terminal portion
reactive with an amine or isocyanate and a terminal portion that is
non-functional or that can react under moisture-cure or
free-radical conditions;
[0061] with the provisos (1) that if no polydiorganosiloxane
monoamine is present, then at least one polyamine is present,
wherein polyamine comprises at least one polydiorganosiloxane
diamine or a mixture of at least one polydiorganosiloxane diamine
and at least one organic polyamine, (2) if only polyisocyanate and
polyamine are present, the molar ratio of isocyanate to amine is
<0.9:1 or >1.1:1, and (3) when polydiorganosiloxane monoamine
and diamine are present, the ratio of total isocyanate available in
the polyisocyanate to the total amine available in the monoamine
and diamine less any amine end groups in the copolymer is about
1:1, to a reactor under substantially solventless conditions;
[0062] mixing the reactants in the reactor under the substantially
solventless conditions;
[0063] allowing the reactants to react to form a
polydiorganosiloxane oligourea segmented copolymer with a average
degree of oligomerization of 2 to 12; and
[0064] conveying the oligomer from the reactor.
[0065] In the solventless process, generally, no solvent is needed
to carry out the reaction, making the process more environmentally
friendly than the solvent process for making polydiorganosiloxane
oligourea segmented copolymers. Small amounts of solvent may be
present, if necessary, to control the flow of solid
polyisocyanates, high viscosity polyisocyanates, low amounts of
polyisocyanates, or for controlled addition of adjuvants such as
tackifying resins, pigments, crosslinking agents, plasticizers,
fillers, and stabilizing agents, or to reduce their viscosity. An
additional benefit of the continuous, solventless process of the
present invention is the ability to extrude the
polydiorganosiloxane polyurea segmented oligomer into thick
constructions, into patterned shapes or onto irregularly-shaped
surfaces directly after polymerization.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0066] Different polyisocyanates in the reaction will modify the
properties of the polydiorganosiloxane oligourea segmented
copolymer. For example, if a polycarbodiimide-modified
diphenylmethane diisocyanate, such as ISONATE.TM. 143L, available
from Dow Chemical Co., is used, the resulting polydiorganosiloxane
oligourea segmented copolymer has superior solvent resistance when
compared with other polyisocyanates. If tetramethyl-m-xylylene
diisocyanate is used, the resulting segmented copolymer may be a
semisolid to solid gel that has a very low melt viscosity that
makes it particularly useful, in potting and sealant applications
where thermal reversibility is advantageous.
[0067] Any diisocyanate that can be represented by the formula
OCN-Z-NCO
[0068] wherein Z is as defined above, can be used in the present
invention. Examples of such diisocyanates include, but are not
limited to, aromatic diisocyanates, such as 2,6-toluene
diisocyanate, 2,5-toluene diisocyanate, 2,4-toluene diisocyanate,
m-phenylene diisocyanate, p-phenylene diisocyanate, methylene
bis(o-chlorophenyl diisocyanate),
methylenediphenylene-4,4'-diisocyanate, polycarbodiimide-modified
methylenediphenylene diisocyanate, (4,4'-diisocyanato-3,3', 5,
5'-tetraethyl) biphenylmethane,
4,4'-diisocyanato-3,3'-dimethoxybiphenyl (o-dianisidine
diisocyanate), 5-chloro-2,4-toluene diisocyanate,
1-chloromethyl-2,4-diisocyanato benzene, aromatic-aliphatic
diisocyanates such as m-xylylene diisocyanate,
tetramethyl-m-xylylene diisocyanate, aliphatic diisocyanates, such
as 1,4-diisocyanatobutane, 1,6-diisocyanatohexane,
2,2,4-trimethylhexyl diisocyanate, 1,12-diisocyanatododecane,
2-methyl-1,5-diisocyanatopentane, and cycloaliphatic diisocyanates
such as methylenedicyclohexylene-4,4'-diisoc- yanate, and
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate and
mixtures thereof.
[0069] Preferred diisocyanates include 2,6-toluene diisocyanate,
methylenediphenylene-4,4'-diisocyanate, polycarbodiimide-modified
methylenediphenyl diisocyanate, o-dianisidine diisocyanate,
tetramethyl-m-xylylene diisocyanate,
methylenedicyclohexylene-4,4'-diisoc- yanate,
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone
diisocyanate), 2,2,4-trimethylhexyl diisocyanate,
1,6-diisocyanatohexane, and cyclohexylene-1,4-diisocyanate.
Particularly preferred is tetramethyl-m-xylylene diisocyanate and
mixtures thereof.
[0070] Any triisocyanate that can react with a monoamine and
polyamine can be used in the present invention. Examples of such
triisocyanates include, but are not limited to, polyfunctional
isocyanates, such as those produced from biurets, isocyanurates,
adducts, and the like, may be used. Some commercially available
polyisocyanates include portions of the DESMODUR.TM. and MONDUR.TM.
series from Bayer and the PAPI series of Dow Plastics.
[0071] Preferred triisocyanates include DESMODUR.TM. N3300 and
MONDUR.TM. 489.
[0072] Terminal Groups
[0073] Polydiorganosiloxane monoamines useful in the present
invention as end capping agents can be represented by the formula
6
[0074] where D, R, X(c), Y and q are as described above, and
include those having number average molecular weights in the range
of about 700 to 150,000. Preferred are polydiorganosiloxane
monoamines prepared as deescribed in U.S. Pat. No. 5,091,483,
wherein such description is incorporated herein by reference. The
polydiorganosiloxane monoamines can be prepared, for example, from
the reaction of cyclic organotrisiloxanes with alkyl lithium
reagents in tetrahydrofuran to yield lithium
polydiorganosiloxanolates that are subsequently reacted with
aminoalkylfluorosilanes as terminating agents to provide the
polydiorganosiloxane monoamine product.
[0075] Examples of siloxane monoamines useful in the present
invention include polydimethylsiloxane monoamine,
polydiphenylsiloxane monoamine, polytrifluoropropylmethylsiloxane
monoamine, polyphenylmethylsiloxane monoamine, polydiethylsiloxane
monoamine, polydivinylsiloxane monoamine, polyvinylmethylsiloxane
monoamine, and copolymers thereof and mixtures thereof.
[0076] Suitable endcapping agents for polydiorganosiloxane
oligourea segmented copolymers that would be terminated with amine
groups, were no endcapping agent present, and that provide terminal
groups that are not reactive under moisture curing or free radical
curing conditions include but are not limited to monoisocyanates
such as alkyl isocyanates, such as benzyl isocyanate, cyclohexyl
isocyanate, n-dodecyl isocyanate, n-octadecyl isocyanate, octyl
isocyanate, 2-phenylethyl isocyanate, trimethylsilyl isocyanate,
undecyl isocyanate; and aryl isocyanates, such as 4-bromophenyl
isocyanate, 2-chlorophenyl isocyanate, 2,4-dimethylphenyl
isocyanate, 1-naphthyl isocyanate, phenyl isocyanate, 4-tolyl
isocyanate, 4-trifluoromethylphenyl isocyanate,
2,4,6-trimethylphenyl isocyanate.
[0077] Suitable endcapping agents for polydiorganosiloxane
oligourea segmented copolymers that would be terminated with
isocyanate groups, were no endcapping agent present, and provide
terminal groups that are not reactive under moisture curing or free
radical curing conditions include but are not limited to organic
monoamines such as propylamine, cyclohexylamine, aniline,
benzylamine, octadecylamine, phenylethylamine, and polyoxyalkylene
monoamine, such as those that can be obtained from Huntsman, Corp.
under the tradename of Jeffamine, polyethylene oxide, polypropylene
oxide, copolymers thereof and mixtures thereof.
[0078] Suitable endcapping agents for polydiorganosiloxane
oligourea segmented copolymers that would be terminated with amine
groups, were no endcapping agent present, and that provide terminal
groups that are reactive under free radical curing conditions,
include but are not limited to isocyanatoethyl methacrylate;
alkenyl azlactones such as vinyl dimethyl azlactone and isopropenyl
dimethyl azlactone, m-isopropenyl-.alpha.,.alpha.-dimethyl benzyl
isocyanate, and acryloyl ethyl carbonic anhydride. Some endcapping
agents that can react with amine groups, e.g., isocyanatoethyl
methacrylate, are commercially available, and others can be
prepared using known methods. Alkenyl azlactones and their
preparations are described, for example, in U.S. Pat. No.
4,777,276, wherein such description is incorporated herein by
reference. Acryloyl ethyl carbonic anhydride can be prepared from
ethyl chloroformate and acrylic acid as described in R. Hatada et
al., Bull. Chem. Soc, Japan, 41 (10), 2521 (1968). Preferred
endcapping agents for polydiorganosiloxane oligourea segmented
copolymers that would be amine terminated if no endcapping agent
were present include, for example, isocyanatoethyl methacrylate,
vinyl dimethyl azlactone, and acryloyl ethyl carbonic
anhydride.
[0079] Suitable endcapping agents for polydiorganosiloxane
oligourea segmented copolymers that would be amine terminated, if
no endcapping agent were present, to provide terminal groups that
are reactive under nmoisture curing conditions include but are not
limited to isocyanatopropyl trimethoxysilane, isocyanatopropyl
triethoxysilane, isocyanatopropyl dimethoxy
(methylethylketoximino)silane, isocyanatopropyl diethoxy
di(methylethylketoximino)silane, isocyanatopropyl monomethoxy
di(methylethylketoximino)silane, isocyanatopropyl monoethoxy
di(methylethylketoximino)silane, and isocyanatopropyl
tri(methylethylketoximino)silane. Polyisocyanates that serve to
form the copolymer, may also serve as the moisture curable terminal
portion of the copolymer when the number of isocyanate groups
provided by the polyisocyanates exceed the amine groups provided by
the polyamines. Polymers prepared with such endcapping agents can
be further reacted to provide higher molecular weight polymers or
copolymers.
[0080] Suitable endcappiug agents for polydiorganosiloxane
oligourea segmented copolymers that would be isocyanate terminated
if no endcapping agent were present to provide terminal groups that
are reactive under moisture curing conditions include but are not
limited by aminopropyl trimethoxysilane, aminopropyl
triethoxysilane, aminopropyl methyldimethoxysilane, aminopropyl
methyldiethoxysilane, aminopropyl
dimethoxy(methylethylketoximino)silane, aminopropyl
diethoxy(methylethylketoximino)silane, aminopropyl
monomethoxydi(methylethylketoximino)silane, aminopropyl
monoethoxydi(methylethylketoximino)silane, and aminopropyl
tri(methylethylketoximino)silane mixtures thereof and partial
hydrolyzates thereof. Preferred endcapping agents, for
isocyanate-terminated polydiorganosiloxane polyurea segmented
oligomers, if no erdcapping agents were present to provide terminal
groups that are reactive under various conditions, include those
selected from the group consisting of aminopropyl trimethoxysilane,
aminopropyl triethoxysilane and aminopropyl
methyldiethoxysilane.
[0081] Polydiorganosiloxane diamines useful in the present
invention can be represented by the formula 7
[0082] R, Y, D and p are defined as above and includes those having
number average molecular weights in the range of about 700 to
150,000.
[0083] Preferred diamines are substantially pure
polydiorganosiloxane diamines prepared as described in U.S. Pat.
No. 5,214,119, wherein such description is incorporated herein by
reference. High purity polydiorganosiloxane diamines are prepared
from the reaction of cyclic organosiloxanes and
bis(aminoalkyl)disiloxanes utilizing an anhydrous amino alkyl
functional silanolate catalyst such as tetramethylammonium
3-aminopropyldimethylsilanolate, preferably in an amount less than
0.15 weight percent based on the total weight of the cyclic
organosiloxanes with the reaction run in two stages.
[0084] Particularly preferred are polydiorganosiloxane diamines
prepared using cesium and rubidium catalysts.
[0085] Preparation includes combining under reaction conditions
[0086] (1) an amine functional endcapping agent represented by the
formula: 8
[0087] wherein each R, Y, D andp are defined as above and x is an
integer of about 0 to 150;
[0088] (2) sufficient cyclic siloxane to obtain a
polydiorganosiloxane diamine having a molecular weight greater than
the molecular weight of the end-capping agent and
[0089] (3) a catalytically effective amount of cesium hydroxide,
rubidium hydroxide, cesium silanolate, rubidium silanolate, cesium
polysiloxanolate, rubidium polysiloxanolate, and mixtures
thereof.
[0090] The reaction is continued until substantially all of the
amine functional end-capping agent is consumed. Then the reaction
is terminated by adding a volatile organic acid to form a mixture
of a polydiorganosiloxane diamine usually having greater than about
0.01 weight percent silanol impurities and one or more of the
following, a cesium salt of the organic acid, a rubidium salt of
the organic acid, or both such that there is a small molar excess
of organic acid in relation to catalyst. Then, the silanol groups
of the reaction product are condensed under reaction conditions to
form polydiorganosiloxane diamine having less than or equal to
about 0.01 weight percent silanol impurities while the unreacted
cyclic siloxane is stripped, and, optionally, the salt is removed
by subsequent filtration.
[0091] Examples of polydiorganosiloxane diamines useful in the
present invention include polydimethylsiloxane diamine,
polydiphenylsiloxane diamine, polytrifluoropropylmethylsiloxane
diamine, polyphenylmethylsiloxane diamine, polydiethylsiloxane
diamine, polydivinylsiloxane diamine, polyvinylmethylsiloxane
diamine, poly(5-hexenyl)methylsiloxane diamine, mixtures and
copolymers thereof.
[0092] Examples of organic polyamines useful in the present
invention include but are not limited to polyoxyalkylene diamine,
such as D-230, D-400, D-2000, D-4000, DU-700, ED-2001 and EDR-148,
all available from Huntsman, polyoxyalkylene triamine, such as
T-3000 and T-5000 available from Huntsman, polyalkylenes, such as
Dytek A and Dytek EP, available from DuPont.
[0093] The above polyamines, polyisocyanates, and endcapping agents
are used in the appropriate stoichiometric ratios to obtain curable
polydiorganosiloxane oligourea segmented copolymers with the
desired average degree of polymerization.
[0094] Silane agents may be used to crosslink the moisture curable
polysiloxane oligourea segmented copolymers of the present
invention. Suitable silane agents generally have the formula
R".sub.nSiW.sub.4-n where R" is a monovalent hydrocarbon group,
(for example, an alkyl, alkylenyl, aryl, or alkaryl group), n is 0,
1 or 2, and W is a monovalent hydrolyzable group such as a
dialkylketoximino group, (for example, methylethylketoximino,
dimethylketoximino, or diethylketoximino), alkoxy group (for
example, methoxy, ethoxy, or butoxy), alkenoxy group (for example,
isopropenoxy), acyloxy group) (for example, acetoxy), alkamido
group (for example, methylacetamido or ethylacetamido), or
acylamido group (for example, phthalimidoamido). Silane
crosslinking agents falling within this category are commercially
available, for example, from Silar Laboratories, Scotia, N.Y.
Particularly preferred silane crosslinking agents are
dialkylketoximinosilanes because they exhibit good shelf-stability
and do not form deleterious by-products upon cure. Examples include
methyltri(methylethylketoximino) silane and
vinyltri(methylethylketoximino) silane, both of which are
commercially available from Allied-Signal, Inc. Morristown, N.J.,
and alkoxysilanes available from OSi Chemicals, Lisle, Ill.
[0095] The free radically curable polydiorganosiloxane oligourea
segmented copolymer compositions of the invention can, depending
upon their viscosity, be coated, extruded, or poured, and rapidly,
completely, and reliably radiation cured to elastomers (even at
high molecular weight) by exposure to electron beam, visible or
ultraviolet radiation. Curing should be carried out in as
oxygen-free an environment as possible, e.g., in an inert
atmosphere such as nitrogen gas or by utilizing a barrier of
radiation-transparent material having low oxygen permeability.
Curing can also be carried out under an inerting fluid such as
water. When visible or ultraviolet radiation is used for curing,
the silicone compositions may also contain at least one
photoinitiator. Suitable photoinitiators include benzoin ethers,
benzophenone and derivatives thereof, acetophenone derivatives,
camphorquinone, and the like. Photoinitiator is generally used at a
concentration of from about 0.1% to about 5% by weight of the total
polymerizable composition, and, if curing is carried out under an
inerting fluid, the fluid is preferably saturated with the
photoinitiator or photoinitiators being utilized in order to avoid
the leaching of initiator from the silicone composition. The rapid
cure observed for these materials allows for the use of very low
levels of photoinitiator relative to what is known in the art,
hence uniform cure of thick sections can be achieved due to deeper
penetration of radiation. If desired, the silicone compositions of
this invention can also be cured thermally, requiring the use of
thermal initiator such as peroxides, azo compounds, or persulfates
generally at a concentration of from about 1% to about 5% by weight
of the total polymerizable composition. Preferably any thermal or
photoinitiator used is soluble in the silicone compositions
themselves, requiring little or no use of a solvent to dissolve the
initiator.
[0096] Examples of suitable curing catalysts for moisture curable
polydiorganosiloxane oligourea segmented copolymers include alkyl
tin derivatives (e.g., dibutyltindilaurate, dibutyltindiacetate,
and dibutyltindioctoate commercially available as "T-serics
Catalysts" from Air Products and Chemicals, Inc. of Allentown,
Pa.), and alkyl titanates (e.g., tetraisobutylorthotitanate,
titanium acetylacetonate, and acetoacetic ester titanate
commercially available from DuPont under the designation "TYZOR").
In general, however, it is preferred to select silane crosslinking
agents that do not require the use of curing catalysts to avoid
reducing shelf-life and adversely affecting the physical properties
of the composition.
[0097] Other catalysts useful for moisture curable
polydiorganosiloxane oligourea segmented copolymers include acids,
anhydrides, and lower alkyl ammonium salts thereof that include but
are not limited to those selected from the group consisting of
trichloroacetic acid, cyanoacetic acid, malonic acid, nitroacetic
acid, dichloroacetic acid, difluoroacetic acid, trichloroacetic
anhydride, dichloroacetic anhydride, difluoroacetic anhydride,
triethylammonium trichloroacetate, trimethylammonium
trichloroacetate, and mixtures thereof.
[0098] Also useful for curing compositions of this invention are
the well known two component room temperature free radical
curatives consisting of a polymerization catalyst and an
accelerator. Common polymerization catalysts useful in this two
component curative include organic peroxides and hydroperoxides
such as dibenzoyl peroxide, t-butyl hydroperoxide, and cumene
hydroperoxide, that are not active at room temperature in the
absence of an accelerator. The accelerator component of the
curative consists of the condensation reaction product of a primary
or secondary amine and an aldehyde. Common accelerators of this
type are butyraldehyde-aniline and butyraldehyde-butylamine
condensation products sold by E. I. duPont de Nemours & Co. as
Accelerator 808.TM. and Accelerator 833.TM.. This catalyst system
may be employed to prepare a two-part free radically curable
organosiloxane oligourea segmented copolymer where the curable
copolymrer is divided into two parts and to one part is added the
polymerization catalyst and to the other part is added the
accelerator. Upon mixing this two component system cures at room
temperature. Alternatively, the polymerization catalyst can be
incorporated in the free radically curable organosiloxane oligourea
segmented copolymer and the accelerator can be applied to a
substrate such that when the free radically curable organosiloxane
oligourea segmented copolymer containing polymerization catalyst
contacts the "primed" substrate surface, cure proceeds immediately
at room temperature. Those of ordinary skill in the art are
familiar with such cure systems and could readily adapt them to
various product constructions.
[0099] Fillers, tackifying resins, plasticizers, and other property
modifiers may be incorporated in the polydiorganosiloxane polyurea
segmented oligomers of the present invention. Generally, such
modifiers are used in amounts ranging up to about 80 weight
percent. Additives such as dyes, pigments, stabilizers,
antioxidants, compatibilizers, and the like can also be
incorporated into the polydiorganosiloxane polyurea segmented
copolymers of the invention. Generally, such additives are used in
amounts ranging up to about 20 weight percent.
[0100] Specific characteristics of the polydiorganosiloxane
oligourea segmented copolymers of the invention can be influenced
by a number of factors including 1) the nature of the "K" group,
when present, 2) the nature of the diisocyanate group used, 3) the
molecular weight of the polydiorganosiloxane monoamine and/or
polydiorganosiloxane diamine used, 4) the presence of an organic
polyamine, 5) the average degree of oligomerization, and 6) whether
significant excesses of polyisocyanate or polyamine exist. The
nature of the "K" group largely determines whether or not the
copolymer is curable, by what mechanism, and under what
conditions.
[0101] The nature of the isocyanate residue in the
polydiorganosiloxane oligourea segmented copolymer influences
stiffness and flow properties, and also affects the properties of
the cured copolymers. Isocyanate residues resulting from
diisocyanates that form crystallizable ureas, such as
tetramethyl-m-xylylene diisocyanate, 1,12-dodecane diisocyanate,
dianisidine diisocyanate, provide copolymers that are stiffer than
those prepared from methylenedicyclohexylene-4,4'-diisocyanate,
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, and
m-xylylene diisocyanate.
[0102] The molecular weight of the polydiorganosiloxane monoamine
or diamine, if present, affects the elasticity of the
polydiorganosiloxane oligourea segmented copolymers. Lower
molecular weight diamines result in polydiorganosiloxane oligourea
segmented copolymers having higher modulus and higher tensile
strength when cured. Higher molecular weight diamines provide
copolymers having lower modulus but higher strain at break. The
average degree of oligomerization affects the rheological
properties of the uncured oligomer and may affect the mechanical
properties of the cured oligomer. The average degree of
oligomerization affects the rheological properties with increasing
degrees of oligomerization. Excess polyisocyanate or polyamine may
affect the reactivity of the oligomer with other reactive
moieties.
[0103] The materials of the invention can be made by a solvent
process and by a solventless process. In both processes of the
present invention, the reactants and optional nonreactive additives
are mixed in a reactor and allowed to react to form the
polydiorganosiloxane polyurea segmented oligomers having an average
degree of oligomerization of from 2 to 12 and that can then be
removed from the reaction vessel. When isocyanate functional
endcapping agents are utilized, such agents can, for example, be
mixed with the other isocyanate reactants before they are
introduced into the reactor. Similarly, amine-functional endcapping
agents for example, may be mixed with polydiorganosiloxane diamine
reactants before they are introduced into the reactor.
[0104] In the following discussion of the two processes, an
isocyanate functional endcapping agent, different from the
diisocyanate reactant, is utilized.
[0105] For the solvent based process, the reaction solvents and
starting materials are usually purified and dried and the reaction
is carried out under an inert atmosphere such as dry nitrogen or
argon.
[0106] The preferred reaction solvents are those that are
unreactive with the isocyanate functional reactants, the amine
functional reactants and the endcapping agents and that maintain
the reactants and product completely in solution throughout the
polymerization reaction. Generally, chlorinated solvents, ethers,
and alcohols are preferred with aliphatic diisocyanates, with
methylene chloride, tetrahydrofuran, and isopropyl alcohol being
particularly preferred. When reactants include aromatic
diisocyanates such as methylenediphenylene-4,4'-diisocyanate (MDI),
a mixture of tetrahydrofuran with 10% to 25% by weight of dipolar
aprotic solvent such as dimethylformamide is preferred.
[0107] In the substantially solventless process, the flexibility of
the process leads to interesting materials. One skilled in the art
can expect the optimum material for a particular application to be
a function of the architecture and ratios of reactants, mixing
speed, temperature, reactor throughput, reactor configuration and
size, residence time, residence time distribution, optionai
initiator architecture, and whether any fillers, additives, or
property modifiers are added.
[0108] Any reactor that can provide intimate mixing of the
polyisocyanates and polyamines is suitable for use in substantially
solventless process of the present invention. The reaction may be
carried out as a batch process using, for example, a flask equipped
with a mechanical stirrer, provided the product of the reaction has
a sufficiently low viscosity at the processing temperature to
permit mixing, or as a continuous process using, for example a
single screw or twin screw extruder. Preferably, the reactor is a
wiped surface counter-rotating or co-rotating twin screw
extruder.
[0109] Temperatures in the reactor should be sufficient to permit
reaction between the polyisocyanate and the polyamine to occur. The
temperature should be sufficient to permit conveying of the
materials through the reactor, and any subsequent processing
equipment such as, for example, feedblocks and dies. For conveying
the reacted material, the temperature should preferably be in the
range of about 20 to 250.degree. C., more preferably in the range
of about 20 to 200.degree. C. Residence time in the reactor
typically varies from about 5 seconds to 8 minutes, more typically
from about 15 seconds to 3 minutes.
[0110] The residence time depends on several parameters, including,
for example, the length to diameter ratio of the reactor, mixing
rates, overall flowrates, reactants, and the need to blend in
additional materials. For materials involving reaction with minimal
or no blending of a nonreactive component, the reaction can easily
take place in as little as 5:1 length to diameter units of a twin
screw extruder.
[0111] When a wiped surface reactor is used, it preferably has
relatively close clearances between the screw flight lands and the
barrel, with this value typically lying between 0.1 to about 2 mm.
The screws utilized are preferably fully or partially intermeshing
or fully or partially wiped in the zones where a substantial
portion of the reaction takes place.
[0112] Because of the rapid reaction that occurs between the
polyisocyanates and polyamines, the materials are preferably fed
into an extuder at unvarying rates, particularly when using higher
molecular weight polydiorganosiloxane amines, i.e., with number
average molecular weights of about 50,000 and higher. Such feeding
generally reduces undesirable variability of the final product.
[0113] One method of ensuring the continuous feeding of very low
flow polyisocyanate quantities in an extruder is to first mix the
endcapping agent with the polyisocyanate and then to allow the
polyisocyanate and isocyanate-functional endcapping agent feed line
to touch or very nearly touch the passing threads of the screws.
Another method would be to utilize a continuous spray injection
device that produces a continuous stream of fine droplets of the
polyisocyanate and isocyanate-functional endcapping agent into the
reactor.
[0114] However, the various reactants and additives can be added in
any order provided the addition of an additive does not interfere
with the reaction of the reactants. An additive that is
particularly reactive with a polyisocyanate reactant typically
would not be added until after the reaction of the polyisocyanate
with a polyamine reactant. Further, the reactants can be added
simultaneously or sequentially into the reactor and in any
sequential order, for example, the polyisocyanate stream can be the
first component added into the reactor in a manner such as
mentioned above. Polyamine can then be added downstream in the
reactor. Alternately, the polyisocyanate stream can also be added
after the polyamine has been introduced into the reactor.
[0115] The process of the present invention has several advantages
over conventional solution polymerization processes for making
polydiorganosiloxane polyurea segmented copolymers such as (1) the
ability to vary the polyisocyanate-to-polyamine ratio to obtain
materials with properties superior to solution polymerized
materials, (2) the capabiility of polymerizing high molecular
weight compositions that cannot be easily produced using solution
polymerization, (3) the ability to directly produce shaped articles
with reduced heat histories, (4) the ability to directly blend in
fillers, tackifying resins, plasticizers, and other property
modifiers, and (5) the elimination of solvent.
[0116] The flexibility of altering the polyisocyanate-to-polyamine
ratio in the continuous process is a distinct advantage. This ratio
can be varied above and below the theoretical value of 1:1 quite
easily.
[0117] The polyisocyanate and isocyanate-functional endcapping
agent stream can be the first component added into the reactor in a
manner such as mentioned above. The polydiorganosiloxane amine can
then be added downstream in the reactor. Alternately, the
diisocyanate and isocyanate functional endcapping agent stream can
also be added after the polydiorganosiloxane amine stream has been
introduced into the reactor.
[0118] In formulating the polydiorganosiloxane oligourea segmented
copolymers with components such as tackifying resins, inorganic
fillers, plasticizers or other materials essentially non-reactive
with the polydiorganosiloxane polyurea segmented oligomer
reactants, the materials to be blended can be added further
downstream in the reactor after a substantial portion of the
reaction of the diisocyanate, the polydiorganosiloxane amine, and
the isocyanate functional endcapping agent has taken place. Another
suitable order of addition is addition of the polydiorganosiloxane
amine first, the additive second, and the diisocyanate and
isocyanate functional endcapping agent third, with the diisocyanate
and the endcapping agent fed in a continuous manner. If the
additive can be conveyed in the reactor, it can be added into the
reactor first with the polydiorganosiloxane amine, diisocyanate,
and isocyanate functional endcapping agent following separately at
later stages in the process.
[0119] The substantially solventless process of the present
invention has several advantages over conventional solution
polymerization processes for making polydiorganosiloxane oligourea
segmented copolymers such as the ability to directly produce shaped
articles with reduced heat histories, the ability to directly blend
in fillers, tackifying resins, and other property modifiers, and
the elimination of solvent. Because the polydiorganosiloxane
oligourea segmented copolymers of this invention typically have low
melt viscosities, they can be processed at lower temperature than
can fully chain extended analogs.
[0120] In general, long exposure to heat would be expected to
degrade polydiorganosiloxane oligourea segmented copolymoers and
leads to a degradation of physical properties. The degradation
experienced by certain solution polymerized polydiorganosiloxane
oligourea segmented copolymers upon drying and subsequent hot melt
extrusion is also overcome by the continuous process of the present
invention because reactively extruded polydiorganosiloxane
oligourea segmented copolymers can be extruded directly from the
polymerization zone through a die to form shaped articles such as
tubing and films without the additional heat history associated
with solvent removal and the subsequent oligomer reheating.
[0121] The ability to eliminate the presence of solvent during the
reaction of the diisocyanate, the endcapping agent and the optional
polydiorganosiloxane di or mono amine yields a much more efficient
reaction. The average residence time using the process of the
present invention is typically 10 to 1000 times shorter than that
required in solution polymerization. A small amount of solvent can
be added, if necessary, e.g., from about 0.5% up to about 5% of the
total composition, in this process either as a carrier for
injecting otherwise solid materials or in order to increase
stability of an otherwise low flowrate stream of material into the
reaction chamber.
[0122] While the continuous solventless process for making the
copolymers has many advantages over the solvent process, there may
be some situations where the solvent process is preferred or where
a combination of the two is preferred. In the later case,
polydiorganosiloxane oligourea segmented copolymer could be made by
the continuous process and subsequently mixed in solvent with
thermal initiators, photoinitiators, tackifying resins,
plasticizers and/or filler components.
[0123] The ability to eliminate the presence of solvent during the
reaction of polyamine and polyisocyanate yields a much more
efficient reaction. The average residence time using the process of
the present invention is typically 10 to 1000 times shorter than
that required in solution polymerization. A small amount of
non-reactive solvent can be added, if necessary, for example, from
about 0.5% up to about 5% of the total composition, in this process
either as a carrier for injecting otherwise solid materials or in
order to increase stability of an otherwise low flowrate stream of
material into the reaction chamber.
[0124] This invention is further illustrated by the following
examples that are not intended to limit the scope of the invention.
In the examples all parts and percentages are by weight unless
otherwise indicated. All molecular weights reported are number
average molecular weights in grams/mol.
[0125] Titration of Polydiorganosiloxane and Organic Diamines
[0126] Multiple lots of some of the diamines were synthesized for
various examples. The actual number average molecular weight of
polydiorganosiloxane or organic diamines were determined by the
following acid titration. Sufficient diamine to yield about 1
milliequivalent of amine is dissolved in 50/50
tetrahydrofuran/isopropyl alcohol to form a 10% solution. This
solution was titrated with 1.0N hydrochloric acid with bromophenyl
blue as an indicator to determine number average molecular weight
The molecular weights are dependent on the exact ratio of the
reactants used in the diamine synthesis and the extent of stripping
cyclic siloxanes. Remaining cyclics are diluents that increase the
apparent molecular weight of polydiorganosiloxane diamine.
Preparation of Polydiorganosiloxane Diamines
[0127] Polydimethylsiloxane Diamine A
[0128] A mixture of 4.32 parts bis(3-aminopropyl)tetramethyl
disiloxane and 95.68 parts octamethylcyclotetrasiloxane, was placed
in a batch reactor and purged with nitrogen for 20 minutes. The
mixture was then heated in the reactor to 150.degree. C. Catalyst,
100 ppm of 50% aqueous cesium hydroxide, was added and heating
continued for 6 hours until the bis(3-aminopropyl) tetramethyl
disiloxane had been consumed. The reaction mixture was cooled to
90.degree. C., neutralized with excess acetic acid in the presence
of some triethylamine, and heated under high vacuum to remove
cyclic siloxanes over a period of at least five hours. The material
was cooled to ambient temperature, filtered to remove any cesium
acetate that had formed, and titrated with 1.0M hydrochloric acid
to determine number average molecular weight. Two lots were
prepared and the molecular weights of Polydimethylsiloxane Diamine
A were Lot 1:5280 and Lot 2:5310.
[0129] Polydimethylsiloxane Diamine B
[0130] Polydimethylsiloxane diamine was prepared as described for
Polydimethylsiloxane Diamine A except 2.16 parts
bis(3-aminopropyl)tetram- ethyl disiloxane and 97.84 parts
octamethylcyclotetrasiloxane were used. Two lots were prepared. The
molecular weight of Polydimethylsiloxane Diamine B was 10,700.
[0131] Polydimethylsiloxane Diamine C
[0132] A mixture of 21.75 parts Polydimethylsiloxane Diamine A and
78.25 parts octamethylcyclotetrasiloxane was placed in a batch
reactor, purged with nitrogen for 20 minutes and then heated in the
reactor to 150.degree. C. Catalyst, 100 ppm of 50% aqueous cesium
hydroxide, was added and heating continued for 3 hours until
equilibrium concentration of cyclic siloxanes was observed by gas
chromatography. The reaction mixture was cooled to 90.degree. C.,
neutralized with excess acetic acid in the presence of some
triethylamine, and heated under high vacuum to remove cyclic
siloxanes over a period of at least 5 hours. The material was
cooled to ambient temperature, filtered, and titrated with 1.0N
hydrochloric acid to determine number average molecular weight. The
molecular weight of resulting Polydimethylsiloxane Diamine C was
22,300.
[0133] Polydimethylsiloxane Diamine D
[0134] Polydimethylsiloxane diamine was prepared as described for
Polydimethylsiloxane Diamine C except 12.43 parts
Polydiorganosiloxane Diamine A and 87.57 parts
octamethylcyclotetrasiloxane were used. Two lots were prepared. The
molecular weights of the resulting Polydimethylsiloxane Diamine D
were Lot 1-35,700 and Lot 2-37,800.
[0135] Polydimethylsiloxane Diamine E
[0136] Polydimethylsiloxane diamine was prepared as described for
Polydimethylsiloxane Diamine C except that 8.7 parts
Polydimethylsiloxane Diamine A and 91.3 parts
octamethylcyclotetrasiloxane were used. The molecular weight of the
thus-produced Polydimethylsiloxane Diamine E was 50,200.
[0137] Polydiphenyldimethylsiloxane Diamine F
[0138] To a 3-necked round bottom flask fit with mechanical
stirrer, static nitrogen atmosphere, oil heating bath, thermometer,
and reflux condenser, were added 75.1 parts
octamethylcyclotetrasiloxane, 22.43 parts
octaphenylcyclotetrasiloxane, and 2.48 parts
bis(3-aminopropyl)tetramethyl disiloxane. Under static nitrogen
atmosphere, the reactants were heated to 150.degree. C. and
degassed under aspirator vacuum for 30 seconds before restoring
static nitrogen atmosphere. A charge of 0.2 grams cesium hydroxide
solution (50% aqueous) was added to the flask and heating continued
for 16 hours at 150.degree. C. The flask was cooled to ambient
temperature and then 2 mL triethylamine and 0.38 mL acetic acid
were added. With good agitation flask was placed under a vacuum of
100 N/m.sup.2 (100 Pa), heated to 150.degree. C., and maintained at
150.degree. C. for 5 hours to remove volatile materials. After 5
hours heat was removed and contents cooled to ambient temperature.
The molecular weight of Polydiphenyldimethylsiloxane Diamine F was
9620.
Preparation of Polydimethylsiloxane Monoamines
[0139] The following polydimethylsiloxane monoamines were
synthesized for various examples according to the procedures of
U.S. Pat. No. 5,091,483 Example 6 (terminating agent) and Example
10 (silicone monoamine). The actual number average molecular weight
of the different lots are determined by acid titration.
[0140] Aminopropyldimethylfluorosilane Terminating Agent
[0141] To a 500 mL 3-necked round bottom flask was added 49.6
grains 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 29.6 grams
ammonium fluoride, and 300 mL cyclohexane. While heating under
reflux, water was removed by means of Dean-Stark trap. After 18
hours, 4.4 mL of water was collected, and the clear, colorless
solution was transferred while warm to a 500 mL 1-neck round bottom
flask. The solvent was removed on a rotary evaporator to provide
165 grams of white solid. The solid was dissolved in 200 ml
methylene chloride, 30 grams of hexamethyl disilazane was added,
and the mixture was stirred and heated under reflux for 5 hours.
The mixture was filtered and the solvent removed under aspirator
vacuum. The product was distilled (boiling point of 70.degree. C.)
under aspirator vacuum to provide 3aminopropyldimethylfluorosilane
as a clear, colorless oil. The yield was 54 grams (100%), that was
determined to be pure by vapor phase chromatography. The structure
was confirmed by NMR spectroscopy.
[0142] Polydimethylsiloxane Monoamine A
[0143] To 1.6 parts of 2.5 M n-butyl lithium were added 7.4 parts
of octamethylcyclotetrasiloxane that had been purged with argon and
the mixture was then stirred for 30 minutes; 500 parts of 50%
hexamethylcyclotrisiloxane in dry tetrahydrofuran was added and the
reaction mixture stirred at room temperature for 18 hours until the
polymerization was complete. To the resulting viscous syrup was
added 3.4 parts 3-aminopropyldimethylfluorosilane terminating
agent. The viscosity rapidly decreased. After stirring for 2 hours,
the solvent was distilled off on a rotary evaporator. The product
was filtered to remove lithium fluoride and provided
Polydimethylsiloxane Monoamine A as a clear, colorless oil. The
number average molecular weight of Polydimethylsiloxane Monoamine A
was 9800.
[0144] Polydimethylsiloxane Monoamine B
[0145] To 1.6 parts of 2.5 M n-butyl lithium were added 7.4 parts
of octamethylcyclotetrasiloxane that had been purged with argon and
the mixture was then stirred for 30 minutes; 1000 parts of 50%
hexamethylcyclotrisiloxane in dry tetrahydrofuran was added and the
reaction mixture stirred at room temperature for 18 hours until
polymerization was complete. To the resulting viscous syrup was
added 3.4 parts 3-aminopropyldimethylfluorosilane terminating
agent. The viscosity rapidly decreased. After stirring for 2 hours,
the solvent was distilled off on a rotary evaporator. The product
was filtered to remove lithium fluoride and provided 500
Polydimethylsiloxane Monoamine B as a clear, colorless oil. The
number average molecular weight was 20,600.
[0146] Polydimethylsiloxane Monoamine C
[0147] To 588 grams (2.64 mol) hexamethylcyclotrisiloxane which had
been degassed via boiling then cooled to room temperature was added
500 mL dry tetrahydrofuran. To this solution was added 19.3 mL
(0.05 mol) of 2.59 M n-butyl lithium and the reaction mixture
stirred at room temperature for 6.5 hours until the polymerization
was complete. To the resulting viscous syrup was added 23.2 mL
(0.06 mol) of 2.58M 3-aminopropyldimethyl fluorosilane terminating
agent. After stirring overnight the solvent and remaining
hexamethylcyclotrisiloxane were distilled off on a rotary
evaporator to afford thc Polydimethylsiloxane Monoamine C as a
clear, colorless oil. The number average molecular weight of
Polydimethylsiloxane Monoamine C was 12,12 l.
[0148] The following test methods were used to characterize the
polydiorganosiloxane oligourea segmented copolymers produced in the
following examples:
Sample Characterization
[0149] Characterization of Uncured Samples
[0150] Rheological properties of the uncured materials were
determined using Rheometrics, RDA II Rheometer using dynamic
temperature ramp mode (-30.degree. C.-175.degree. C.) at a ramp
rate of 5.degree. C., 25 mm parallel plates, a strain of 2.0% and a
frequency of 10.0 rad/s. Sample thickness was 1-2 mm.
[0151] The storage modulus, G', represents that portion of the
mechanical energy that is stored, i.e., completely recoverable,
when the viscoelastic material undergoes cyclic deformation. The
stored energy is analogous to that seen in a simple spring going
through cyclic deformation.
[0152] The loss modulus, G", represents that portion of the
mechanical energy dissipated, i.e., converted to heat, when the
viscoelastic material undergoes cyclic deformation. The dissipated
energy is analogous to that seen in a simple dashpot going through
cyclic deformation.
[0153] Stress Rheometer, Rheometrics, DSR, was used to characterize
shear creep viscosities of the uncured materials in step stress
(creep) mode with 25 mm parallel plates.
[0154] Characterization of Cured Samples
[0155] Free-radically curable materials were squeezed between two
polyester films to a thickness of approximately 1 mm and cured at
an intensity of 1.73 mW for a given length of time with low
intensity ultraviolet lights. Mechanical properties of the cured
samples were characterized as follows:
[0156] Mechanical testing was performed on an Instron Model 1122
tensile tester. Testing was performed according to a modification
of ASTM D412-83. Samples were prepared according to Method B (cut
ring specimens). Type 1 rings (5.1 cm circumference) were produced
with a specially-designed precision ring cutter. The Instron analog
output signal was routed to a digital voltmeter with accuracy
better than 0.5 percent and the digital readings were recorded by a
computer. Modifications to the ASTM were as follows:
[0157] 1. The crosshead speed was 12.7 cm/min rather than 50.8
cm/min.
[0158] 2. The test fixture shafts (upper and lower jaw) both
rotated at 30 RPM in the same direction in order to maintain
uniform strain throughout the entire ring.
[0159] 3. The thickness of the rings was 1 mm.
[0160] Molecular Weight
[0161] The weight average and number average molecular weights of
selected polydimethylsiloxane oligourea segmented copolymers were
determined via gel permeation chromatography with a HP 1090
Chromatograph equipped with a HP 1037A Refractive Index detector, a
Waters 590 pump, a Waters Wisp auto-injector, and a Kariba column
oven at R.T. The copolymer was dissolved in DMF w/v 0.05% LiBr at
15 mg/5 mL, filtered with a 0.2 micron nylon filter, and 100
microliters injected into a Jordi Mixed Bed column. The elution
rate was 0.5 mL/min in DMF+0.05% w/v LiBr. Calibration was based on
Polystyrene standards from Pressure Chemical Company, Pittsburgh,
Pa. thus reported molecular weights are the Polystyrene
equivalents.
EXAMPLES
[0162] In the following Examples, all diisocyanates were used as
received and the diisocyanate:diamine ratios were calculated using
the diisocyanate molecular weight reported by the diisocyanate
supplier and the diamine molecular weight as determined by acid
titration. In the Examples all parts and percentages are by weight
unless otherwise indicated. All molecular weights reported are
number average molecular weights in grams/mole.
Examples 1-5
[0163] In Example 1, 40.0 parts (4.0 mmoles) of
Polydimethylsiloxane Monoamine A, molecular weight 9,800, was
degassed under vacuum at 100.degree. C. and 0.49 parts (2.0 mmoles)
tetramethyl-m-xylylene diisocyanate in 5.0 parts toluene was added
dropwise while stirring. Then 5 mL of 2-propanol was added to
reduce the viscosity, and the resulting polydimethylsiloxane
oligourea segmented copolymer was poured into a Petri dish and air
dried.
[0164] In Example 2, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 1, except 80.0 parts (3.90
mmoles) of Polydimethylsiloxane Monoamine X, molecular weight
20,600 was substituted for Monoamine A.
[0165] In Example 3, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 1, except 0.46 parts (2.0
mmoles) of 1,12-diisocyanatododecane was substituted for the
tetramethyl-m-xylylene diisocyanate.
[0166] In Example 4, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 1, except 0.59 parts (2.0
mmoles) 4,4'-diisocyanato-3,3'-dimethoxybiphenyl was substituted
for the tetramethyl-m-xylylene diisocyanate.
[0167] In Example 5, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 1, except 0.52 parts (2.0
mmoles) of methylenedicyclohexylene-4,4'-diisocyanate was
substituted for the tetramethyl-m-xylylene diisocyanate and
2-propanol was not added.
[0168] The storage modulus, G', the loss modulus, G", the crossover
modulus and crossover temperature were determined for the
polydimethylsiloxane oligourea segmented copolymers of Examples
1-4, each being gel-like and having an average degree of
oligomerization of 2 and being nonfunctional. The copolymer of
Example 5 flowed at room temperature and, thus, had a shear creep
viscosity too low to characterize by the method used. The results
are set forth in Table 1.
2TABLE 1 G' at G" at Crossover Crossover 25.degree. C. 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 1 8.0 .times.
10.sup.4 0.8 .times. 10.sup.4 -- .about.140 2 10.0 .times. 10.sup.4
0.28 .times. 10.sup.4 -- 100 3 0.3 .times. 10.sup.4 0.2 .times.
10.sup.4 0.13 .times. 10.sup.4 28 4 3.8 .times. 10.sup.4 0.08
.times. 10.sup.4 0.4 .times. 10.sup.4 127
[0169] The data in Table 1 demonstrates that the
polydimethylsiloxane oligourea segmented copolymer prepared using
aromatic or aromatic-aliphatic diisocyanates, Examples 1 and 4, had
higher storage moduli and crossover temperature than the copolymer
prepared using an aliphatic diisocyanate, Example 3. Further, the
copolymers vary in storage modulus from 10.times.10.sup.4,
indicating a firmer gel, to 0.3.times.10.sup.4, indicating a very
soft gel, to a viscous liquid (Example 5).
Examples 6-10
[0170] In Example 6, a mixture of 79 parts (8.0 mmoles) of
Polydimethylsiloxane Monoamine A, molecular weight 9,800, and 21
parts (4.0 mmoles) of Polydimethylsiloxane Diamine A, molecular
weight 5280, was dissolved in 69 parts toluene and 1.96 parts (8.0
mmoles) of tetramethyl-m-xylylene diisocyanate in 40 parts toluene
was added dropwise under agitation at room temperature. The
resulting polydimethylsiloxane oligourea segmented copolymer was
air dried.
[0171] In Example 7, a mixture of 57.9 parts (5.9 mmoles) of
Polydimethylsiloxane Monoamine A, molecular weight 9,800, and 15.6
parts (2.95 mmoles) of Polydimethylsiloxane Diamine A, molecular
weight 5280, was dissolved in 75 parts toluene and 1.54 parts (5.9
mmoles) of methylenedicyclohexylene-4,4'-diisocyanate in 25 parts
toluene was added dropwise under agitation at room temperature The
resulting polydimethylsiloxane oligourea segmented copolymer was
air dried.
[0172] In Example 8, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 6, except 1.98 parts (7.9
mmoles) of 1,12-diisocyanatododecane was substituted for the
tetramethyl-m-xylylene diisocyanate.
[0173] In Example 9, a mixture of 87.8 parts (4.25 mmoles) of
Polydimethylsiloxane Monoamine B, molecular weight 20,600 and 11.2
parts (2.12 mmoles) of Polydimethylsiloxane Diamine A, molecular
weight 5280, was dissolved in 52 parts toluene and 1.04 parts (4.25
mmoles) of tetramethyl-m-xylylene diisocyanate in 34 parts toluene
was added dropwise under agitation at room temperature. The
resulting polydimethylsiloxane oligourea segmented copolymer was
air dried.
[0174] In Example 10, a mixture of 65.8 parts (3.19 mmoles) of
Polydimethylsiloxane Monoamine B, molecular weight 20,800, and 8.4
parts (1.59 mmoles) of Polydimethylsiloxane Diamine A molecular
weight 5280, was dissolved in 96 parts toluene and 0.80 parts (3.18
mmoles) of 1,12-diisocyanatododecane diisocyanate in 22 parts
toluene was added dropwise under agitation at room temperature. The
resulting polydimethylsiloxane oligourea segmented copolymer was
air dried.
[0175] The polydimethylsiloxane oligourea segmented copolymers of
each of Examples 6-10 had an average degree of oligomerization of
3. The copolymers of Examples 6, 8, 9 and 10 exhibited no cold
flow, that is, did not change shape at ambient conditions, while
the copolymer of Example 7 did exhibit cold flow. The storage
modulus, G', loss modulus, 6", crossover modulus and crossover
temperature were determined for the polydimethylsiloxane oligourea
segmented copolymers of Examples 6-10. The results are set forth in
Table 2.
3TABLE 2 G' at G" at Crossover Crossover 25.degree. C. 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 6 20 .times.
10.sup.4 3.0 .times. 10.sup.4 5 .times. 10.sup.4 141 7 6.0 .times.
10.sup.4 2.0 .times. 10.sup.4 2.7 .times. 10.sup.4 45 8 13 .times.
10.sup.4 1.7 .times. 10.sup.4 0.5 .times. 10.sup.4 53 9 10 .times.
10.sup.4 2.0 .times. 10.sup.4 nd* >150 10 29 .times. 10.sup.4
3.0 .times. 10.sup.4 1.2 .times. 10.sup.4 47 *not determinable
Examples 11-15
[0176] In Example 11, a mixture of 3.25 parts (13.3 mmoles) of
tetramethyl-m-xylylene diisocyanate, 3.93 parts (13.3 mmoles) of
n-octadecyl isocyanate dissolved in 17 parts toluene was added
dropwise under agitation at room temperature to a solution of 105.5
parts (20 mmoles) of Polydimethylsiloxane Diamine A molecular
weight 5,280 in 50 parts of toluene. The resulting
polydimethylsiloxane oligourea segmented copolymer was air
dried.
[0177] In Example 12, a mixture of 3.35 parts (13.3 mmoles) of
1,12-diisocyanatododecane and 3.93 parts (13.3 mmoles) of
n-octadecyl isocyanate dissolved in 29 parts toluene was added
dropwise under agitation at room temperature to a solution of 105.5
parts (20 mmoles) of Polydimethylsiloxane Diamine A molecular
weight 5,280 in 46 parts of toluene. The resulting
polydimethylsiloxane oligourea segmented copolymer was air
dried.
[0178] In Example 13, a mixture of3.41 parts (13.3 mmoles) of
methylenedicyclohexylene-4,4'-diisocyanate and 3.93 parts (13.3
mmoles) of n-octadecyl isocyanate dissolved in 29 parts toluene was
added dropwise under agitation at room temperature to a solution of
105.5 parts (20 mmoles) of Polydimethylsiloxane Diamine A molecular
weight 5,280 in 46 parts of toluene. The resulting
polydimethylsiloxane oligourea segmented copolymer was air
dried.
[0179] In Example 14, a mixture of 3.25 parts (13.3 mmoles) of
tetramethyl-m-xylylene diisocyanate and 1.58 parts (13.3 mmoles) of
phenyl isocyanate dissolved in 11.5 parts toluene was added
dropwise under agitation at room temperature to a solution of 105.5
parts (20 mmoles) of Polydimethylsiloxane Diamine A molecular
weight 5,280 in 95 parts of toluene. The resulting
polydimethylsiloxane oligourea segmented copolymer was air
dried.
[0180] In Example 15, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 14, except a mixture of 3.35
parts (13.3 mmoles) of 1,12-diisocyanatododecane was substituted
for the tetramethyl-m-xylylene diisocyanate.
[0181] The polydimethylsiloxane oligourea segmented copolymers of
Examples 11-15 had an average degree of oligomerization of 3, with
Examples 11-12 and 14-15 exhibiting no cold flow, while Example 13
did exhibit cold flow. The storage modulus, G', the loss modulus,
G", the crossover modulus and crossover temperature were determined
for Examples 11-15. The results are set forth in Table 3.
4TABLE 3 G' at G" at Crossover Crossover 25.degree. C. 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 11 100
.times. 10.sup.4 34 .times. 10.sup.4 1.5 .times. 10.sup.4 116 12
200 .times. 10.sup.4 18 .times. 10.sup.4 .about.1 .times. 10.sup.4
42 13 14 .times. 10.sup.4 10 .times. 10.sup.4 6 .times. 10.sup.4 34
14 190 .times. 10.sup.4 17 .times. 10.sup.4 0.2 .times. 10.sup.4
145 15 50 .times. 10.sup.4 7 .times. 10.sup.4 2 .times. 10.sup.4
48
[0182] The polydimethylsiloxane oligourea segmented copolymers
prepared using n-octadecylisocyanate exhibited higher loss modulus
and lower crossover temperatures than copolymers prepared using
phenyl isocyanate as the end-capper.
[0183] Copolymers prepared with tetramethyl-m-xylylene diisocyanate
possess higher loss modulus and higher crossover temperature than
copolymers prepared with 1,12-diisocyanatododecane.
Example 16
[0184] In Example 16, 60.3 parts (2.71 mmoles) of
Polydimethylsiloxane Diamine C, molecular weight 22,300, was
dissolved in 202 parts methylene chloride, and added dropwise to a
solution of 0.9 parts (3.62 mmoles) of
methylenediphenylene-4,4'-diisocyanate in 25 parts methylene
chloride under agitation at room temperature. The resulting
solution was dried in a vacuum oven at room temperature. The
resulting isocyanate-terminated polydimethylsiloxane oligourea
segmented copolymer having an average degree of oligomerization of
3, was an insoluble, elastomeric material.
Examples 17-28
Example 17
[0185] In Example 17, 52.76 parts (10.00 mmoles)
Polydimethylsiloxane Diamine A molecular weight 5280, was dissolved
in 50 parts toluene, and a mixture of 1.62 parts (6.67 mmoles)
1,12-diisocyanatododecane and 1.03 parts (6.67 mmoles)
isocyanatoethyl methacrylate (available as MOI from Showa Rhodia
Chemicals, Tokyo, Japan) was dissolved in 48 parts toluene and
slowly added at room temperature to the solution with vigorous
stirring. 1.0 part DAROCUR.TM. 1173 (a photoinitiator available
from Ciba-Geigy, Hawthorne, N.Y.) was added per 100 parts copolymer
solution. This solution was then divided into two portions.
[0186] The first portion of the resulting polydimethylsiloxane
oligourea segmented copolymer solution was poured into a Petri dish
and stood at room temperature until the solvent was evaporated. The
storage modulus, G', loss modulus, G", crossover modulus, crossover
temperature and shear creep viscosity at 25.degree. C. and 300
seconds shear time were determined. The results are set forth in
Table 4.
Examples 18-22
[0187] In Examples 18-22, polydimethylsiloxane oligourea segmented
copolymers were prepared as in Example 17, except the
1,12-diisocyanatododecane, was substituted with:
[0188] 1.97 parts (6.67 mmoles)
4,4'-diisocyanato-3,3'-dimethoxybiphenyl (Example 18)
[0189] 1.67 parts (6.67 mmoles) of
methylenediphenylene-4,4'-diisocyanate (Example 19)
[0190] 1.75 parts (6.67 mmoles) of
methylenedicyclohexylene-4,4'-diisocyan- ate (Example 20)
[0191] 1.25 parts (6.67 mmoles) of m-xylylene diisocyanate (Example
21)
[0192] 1.47 parts (6.67 mmoles) of
3-isocyanatomethyl-3,5,5-trimethylcyclo- hexyl isocyanate (Example
22).
[0193] As described in Example 17, each of the copolymer solutions
were separated into two portions. The first portion examples were
dried at room temperature and tested as described above. The
results are set forth in Table 4.
5TABLE 4 Shear creep G' at G" at Crossover Crossover viscosity
25.degree. C. 25.degree. C. Modulus Temp. at 25.degree. C. Example
(Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)* 17 .alpha. .times.
10.sup.4 7.0 .times. 10.sup.4 0.35 .times. 10.sup.4 43 >1
.times. 10.sup.9 (6 kPa) 18 1.9 .times. 10.sup.4 0.9 .times.
10.sup.4 0.5 .times. 10.sup.4 117 7.2 .times. 10.sup.8 (6 kPa) 19
1.0 .times. 10.sup.4 2.0 .times. 10.sup.4 4.9 .times. 10.sup.4 2
5.0 .times. 10.sup.5 (1 Pa) 20 1.7 .times. 10.sup.4 3.0 .times.
10.sup.4 5.0 .times. 10.sup.4 6 5.7 .times. 10.sup.3 (1 Pa) 21 0.06
.times. 10.sup.4 0.3 .times. 10.sup.4 6.0 .times. 10.sup.4 -15 9.0
.times. 10.sup.2 (1 Pa) 22 0.12 .times. 10.sup.4 0.7 .times.
10.sup.4 5.0 .times. 10.sup.4 -15 7.5 .times. 10.sup.2 (1 Pa) *300
seconds shear time; shear stress as indicated in parenthesis
[0194] The polydimethylsiloxane polyurea segmented oligomers of
Examples 17 to 22 had an average degree of oligomerization of 3.
The copolymers of Examples 17-19 exhibited no cold flow while the
copolymers of Examples 20-22 exhibited cold flow.
[0195] The shear creep viscosities of Examples 17-22 varied over a
broad range depending on the diisocyanate used, ranging from
7.5.times.10.sup.2 to >1.times.10.sup.9 Pa.multidot.s, some of
these relatively low molecular weight polymers were semisolid at
room temperature, while others behaved like viscous liquids.
Polydimethylsiloxane oligourea segmented copolymers with
drastically different rheological properties can be made by
selection of the diisocyanate used to prepare the copolymers.
Examples 23-28
[0196] Using the second portion provided in Examples 17-22, the
solvent of these second portions of the resulting
polydimethylsiloxane oligurea segmented copolymer solutions was
evaporated. Separately, each copolymer was squeezed between two
release-coated polyester films, with the release coating facing the
copolymer, to a thickness of about 40 mils. Each sample was
subjected to 1.73 mW of low intensity radiation for 20 minutes to
effect cure. The UV radiation was provided by GE F40BL ultraviolet
bulbs. Each film was removed from the release films and the
mechanical properties, modulus, stress at break, and strain at
break, swelling after being submerged in tetrahydrofuran (THF) for
24 hours calculated by weight, and extractables in the THF for the
cured copolymers were determined. The results are set forth in
Table 5.
6TABLE 5 Stress at Strain at Swelling in Modulus break break THF
Extractables Example (MPa) (MPa) (%) (%) (%) 23 3.74 2.16 150 250
8.6 24 3.61 1.57 70 269 14.8 25 2.10 2.26 180 260 8.2 26 1.51 2.12
180 250 8.4 27 0.68 2.14 204 260 8.5 28 0.86 2.75 210 260 8.5
[0197] When cured, the polydimethylsiloxane oligourea segmented
copolymers possessed similar stress at break and elongation at
break. Tensile moduli of the cured materials that showed less
tendency to flow when uncured, Examples 23-25, were higher than for
those with low shear viscosities, Examples 26-28.
Examples 29-30
Example 29
[0198] In Example 29, Polydimethylsiloxane Diamine A molecular
weight 5280, was fed at a rate of 6.22 g/min (0.00236 equivalents
amine/min) into the first zone of an 18 mm co-rotating twin screw
extruder (available from Leistritz Corporation, Allendale, N.J.)
and a mixture of 50.8 parts by weight tetramethyl-m-xylyene
diisocyanate, 32.2 parts isocyanatoethyl methacrylate, and 17.0
parts DAROCUR.TM. 1173 was fed at a rate of 0.378 g/min. (0.00236
equivalents isocyanate/min) into zone 6. The extruder had a 40:1
length:diameter ratio and double-start fully intermeshing screws
throughout the entire length of the barrel, rotating at 200
revolutions per minute. The temperature profile for each of the 90
mm zones was: zone 1 to 4--25.degree. C.; zone 5--40.degree. C.;
zone 6--60.degree. C.; zone 7--90.degree. C.; zone 8--100.degree.
C.; and endcap--120.degree. C. The resultant polymer was extruded,
cooled in air, and collected. The storage modulus, G', crossover
temperature and shear creep viscosity at 25.degree. C. were
determined. The loss modulus, G", at 25.degree. C. and crossover
modulus were not determinable. The results were as follows:
7 Storage modulus >20 .times. 10.sup.4 Pa Crossover temperature
>170 Shear creep viscosity 3.0 .times. 10.sup.8 Pa .multidot. s
at 6 kPa
Example 30
[0199] In Example 30, a portion of the copolymer of Example 29 was
pressed between polyester films, subjected to ultraviolet
irradiation and tested as in Examples 23-28. The results were as
follows:
8 Modulus 3.59 MPa Stress at break 1.83 MPa Strain at break 140%
Swelling in THF 285% Extractables in THF 11.9
Examples 31-36
Example 31
[0200] In Example 31, 100.0 parts (10.00 mmoles)
Polydimethylsiloxane Diamine B, molecular weight10,700, was
dissolved in 50.0 parts toluene, and a mixture of 1.68 parts (6.67
mmoles) of 1,12-diisocyanatododecane, 1.03 parts (6.67 mmoles) of
isocyanatoethyl methacrylate, and 15.0 parts toluene was slowly
added at room temperature to the solution with vigorous stirring
for 2 hours. Then, about 10 parts of 2-propanol was added and
stirring was continued for 5 hours. 0.50 part DAROCUR.TM. 1173 per
100 parts of polydimethylsiloxane oligourea segmented copolymer was
then to the copolymer solution. The polydimethylsiloxane oligourea
segmented copolymer solution was separated into two portions. The
first portion was poured into a Petri dish and let stand at room
temperature until the solvent was evaporated. The sample was tested
as described in Example 17 and the results are set forth in Table
6.
Examples 32-33
[0201] In Example 32, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 31, except 100.0 parts (4.48
mmoles) Polydimethylsiloxane Diamine C, molecular weight 22,300 was
substituted for Diamine B, and a mixture of 0.75 parts (2.99
mmoles) of 1,12-diisocyanatododecane, 0.46 parts (2.99 mmoles) of
isocyanatoethyl methacrylate, and 15.0 parts of 2-propanol was
used.
[0202] In Example 33, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 31, except 100.0 parts (2.64
mmoles) Polydimethylsiloxane Diamine D (Lot 2), molecular weight
37,800, were substituted for Diamine B and a mixture of 0.43 parts
(1.73 mmoles) of 1,12-diisocyanatododecane, 0.27 parts (1.73
mmoles) of isocyanatoethyl methacrylate, and 15.0 parts of
2-propanol was used.
[0203] The storage modulus, G', the loss modulus, G", the crossover
modulus, the crossover temperature and the shear creep viscosity at
25.degree. C. were determined for the polydimethylsiloxane
oligourea segmented copolymers of Examples 32-33, each having an
average degree of oligomerization of 3. The results, together with
those for Examples 17 and 31, are set forth in Table 6.
9TABLE 6 Shear creep G' at G" at Crossover Crossover viscosity
25.degree. C. 25.degree. C. Modulus Temp. at 25.degree. C. Example
(Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)* 17 .alpha. .times.
10.sup.4 7.0 .times. 10.sup.4 0.35 .times. 10.sup.4 43 >1
.times. 10.sup.9 (6 kPa) 31 10 .times. 10.sup.4 5.0 .times.
10.sup.4 0.5 .times. 10.sup.4 44 8.4 .times. 10.sup.7 (50 Pa) 32
0.9 .times. 10.sup.4 1.2 .times. 10.sup.4 1.3 .times. 10.sup.4 18
7.5 .times. 10.sup.3 (1 Pa) 33 1.3 .times. 10.sup.4 1.3 .times.
10.sup.4 13 .times. 10.sup.4 25 7.4 .times. 10.sup.3 (1 Pa) *300
seconds shear time; shear stress as indicated
[0204] The results in Tables 6 indicate that two opposite factors
affected the rheology of the copolymers of Examples 17 and 31-33.
As the molecular weight of silicone diamine increased, the overall
molecular weight of the polymer increased, while the concentration
of the urea linkages decreased. In the examples, the latter factor
predominated, as shear creep viscosity decreased with increasing
molecular weight of the polydimethylsiloxane diamine.
Examples 34-36
[0205] In Examples 34-36, using the second portion samples of
Examples 31-33, the copolymer solution for each copolymer prepared
was air dried on polyester release liner. These Examples were
prepared and cured as described in Example 23.
[0206] Once cured, the films were removed, the mechanical
properties, modulus and stress at break and strain at break,
swelling after being submerged in tetrahydrofuran (THF) for 24
hours calculated by weight, and extractables in the THF for each
cured copolymer were determined. The results, together with those
for Example 23 are set forth in Table 7.
10TABLE 7 Stress at Strain at Swelling in Modulus break break THF
Extractables Example (MPa) (MPa) (%) (%) (%) 23 3.74 2.16 150 250
8.6 34 0.86 1.17 230 370 19.7 35 0.38 0.59 380 500 9.8 36 0.23 0.67
660 700 14.8
[0207] As can be seen from the data in Table 7, the tensile modulus
of the copolymer prepared using lower molecular weight
polydimethylsiloxane diamine (Example 23) was much higher than for
the copolymers in that higher molecular weight polydimethylsiloxane
diamines were used.
Examples 37-42
Example 37
[0208] In Example 37, 60 parts (6.00 mmoles) Polydimethylsiloxane
Diamine B, molecular weight 10,700, was dissolved in a mixture of
100 parts toluene, 20 parts 2-propanol and a mixture of 0.98 parts
(4.00 mmoles) of tetramethyl-m-xylylene diisocyanate, and 0.62
parts (4.00 mmoles) of isocyanatoethyl methacrylate, and 15.0 parts
toluene was slowly added at room temperature to the solution with
vigorous stirring for 2 hours. Then, about 10 parts of 2-propanol
was added and stirring was continued for 5 hours. 0.50 part
DAROCUR.TM. 1173 per 10 parts of polydimethylsiloxane oligourea
segmented copolymer was then added to the copolymer. This solution
was separated into two portions. One of the portions of the
polydimethylsiloxane oligourea segmented copolymer solution was
poured into a Petri dish and was allowed to stand at room
temperature until the solvent was evaporated. The sample was tested
as descritbed in Example 17 and the results are set forth in Table
8.
Examples 38-39
[0209] In Example 38, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 37, except a mixture of 15.84
parts (3.00 mmoles) Polydimethylsiloxane Diamine A molecular weight
5280, and 66.97 parts (3.00 mmoles) Polydimethylsiloxane Diamine C,
molecular weight 22,300, dissolved in 69.00 parts toluene was
substituted for Diamine B, and a mixture of 0.98 parts (4.00
mmoles) of tetramethyl-m-xylylene diisocyanate and 0.62 parts (4.00
mmoles) of isocyanatoethyl methacrylate was used.
[0210] In Example 39, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 37, except 107.1 parts (3.00
mmoles) Polydimethylsiloxane Diamine D, molecular weight 35,700,
were substituted for Diamine B and dissolved in a mixture of 100
parts toluene, and 10 parts 2-propanol, and a mixture of 0.49 parts
(2.00 mmoles) of tetramethyl-m-xylylene diisocyanate and 0.31 parts
(2.00 mmoles) of isocyanatoethyl methacrylate was used.
[0211] The storage modulus, G', the loss modulus, G", the crossover
modulus,, the crossover temperature, and the shear creep viscosity
at 25.degree. C. were determined for the polydimethylsiloxane
oligourea segmented copolymers of Examples 38-39, each having an
average degree of oligomerization of 3. The results are set forth
in Table 8.
11TABLE 8 Shear creep Ex- G' at G" at Crossover Crossover viscosity
at am- 25.degree. C. 25.degree. C. Modulus Temp. 25.degree. C. ple
(Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)* 37 1.2 .times.
10.sup.4 2.0 .times. 10.sup.4 0.01 .times. 10.sup.4 135 5.0 .times.
10.sup.6 (20 Pa) 38 7.0 .times. 10.sup.4 4.1 .times. 10.sup.4 0.3
.times. 10.sup.4 139 1.2 .times. 10.sup.6 (10 Pa) 39 4.0 .times.
10.sup.4 2.3 .times. 10.sup.4 1.9 .times. 10.sup.4 50 1.5 .times.
10.sup.5 (1 Pa) *300 seconds shear time; shear stress as marked
[0212] The data in Table 8 demonstrate that by using blends of
diamines, improved properties can be obtained. The copolymer of
Example 38, prepared using a polydimethylsiloxane diamine having a
number average molecular weight of 13,800 and prepared from a blend
of polydimethylsiloxane diamines having molecular weights of 5,280
and 22,300, possessed a storage modulus, loss modulus and a
crossover temperature above what would be predicted based on the
data for the copolymers of Examples 37 and 39.
Examples 40-42
[0213] In Examples 40-42, using the second portion samples of
Examples 37-39, the copolymer solution for each copolymer prepared,
was air dried on polyester release liner. These Examples were
prepared and cured as described in Example 23.
[0214] Once cured, the films were removed and the mechanical
properties, modulus, stress at break, strain at break, swelling
after being submerged in tetrahydrofuran (THF) for 24 hours
calculated by weight, and extractables in the THF for each cured
copolymers were determined. The results are set forth in Table
9.
12TABLE 9 Stress at Strain at Swelling Modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 40 1.06 1.14 230 360
19.7 41 1.03 1.87 380 460 9.7 42 0.33 0.70 620 670 13.0
[0215] The data in Table 9 shows that as the molecular weight of
the polydiorganosiloxane diamine increased stress at break
decreased and elongation at break increased. Example 41 shows that
copolymers with high stress at break and high elongation at break
can be obtained using a blend of polydimethylsiloxanes, that is,
52.80 and 22,300 molecular weights.
Examples 43-48
Example 43
[0216] In Example 43, 500 parts (43.0 mmoles) Polydimethylsiloxane
Diamine B, molecular weight 10,700, was dissolved in a mixture of
300 parts toluene and a mixture of 7.51 parts (28.7 mmoles) of
methylenedicyclohexylene-4,4'-diisocyanate, and 4.44 parts (28.7
mmoles) of isocyanatoethyl methacrylate, and 200 parts toluene was
slowly added at room temperature to the solution with vigorous
stirring for 2 hours. Then, about 50 parts of 2-propanol was added
and stirring was continued for 5 hours. 0.50 part DAROCUR.TM. 1173
per 100 parts of polydimethylsiloxane oligourea segmented copolymer
was then added to the copolymer. This solution was separated into
two portions. One of the portions of the polydimethylsiloxane
oligourea segmented copolymer solution was poured into a Petri dish
and was allowed to stand at room temperature until the solvent was
evaporated. The sample was tested as described in Example 17 and
the results, including those of Example 20 are set forth in Table
10.
Examples 44-45
[0217] In Example 44, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 43, except 600 parts (27.0
mmoles) Polydimethylsiloxane Diamine C, molecular weight 22,300,
were substituted for Diamine B and dissolved in 404 parts toluene,
and a mixture of 4.71 parts (19.0 mmoles) of methylene
dicyclohexylene-4,4'-diisocyanate and 2.79 parts (18.0 mmoles) of
isocyanatoethyl methacrylate dissolved in 195 parts toluene were
used.
[0218] In Example 45, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 43, except 100 parts (2.01
mmoles) Polydimethylsiloxane Diamine E, molecular weight 50,200,
dissolved in 123 parts toluene were substituted for Diamine B, and
a mixture of 0.35 parts (1.34 mmoles) or
methylenedicyclohexylene-4,4'-diisocyanate and 0.21 parts (1.34
mmoles) of isocyanatoethyl methacrylate dissolved in 56 parts
toluene was used.
[0219] The storage modulus, G', the loss modulus, G", the crossover
modulus, the crossover temperature and the shear creep viscosity at
25.degree. C. were determined for the polydimethylsiloxane
oligourea segmented copolymers of Examples 44-45, each having an
average degree of oligomerization of 3. The results are set forth,
together with those for Example 20 in Table 10.
13TABLE 10 Shear creep Ex- G' at G" at Crossover Crossover
viscosity at am- 25.degree. C. 25.degree. C. Modulus Temp.
25.degree. C. ple (Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)*
20 1.7 .times. 10.sup.4 3.0 .times. 10.sup.4 5.0 .times. 10.sup.4 6
5.7 .times. 10.sup.3 (1 Pa) 43 4.0 .times. 10.sup.4 3.0 .times.
10.sup.4 2.8 .times. 10.sup.4 35 1.7 .times. 10.sup.4 (1 Pa) 44 4.0
.times. 10.sup.4 2.2 .times. 10.sup.4 1.8 .times. 10.sup.4 68 2.7
.times. 10.sup.4 (1 Pa) 45 3.8 .times. 10.sup.4 1.8 .times.
10.sup.4 1.4 .times. 10.sup.4 65 -- *300 seconds shear time; shear
stress as marked
[0220] The data in Table 10 demonstrates that with increasing
molecular weight of the polydimethylsiloxane diamine used, the
crossover modulus decreased while the crossover temperature
generally increased.
Examples 46-48
[0221] In Examples 46-48, using the second portion samples of
Examples 43-45, respectively the copolymer solution for each
copolymer prepared was air dried on polyester release liner. These
Examples were prepared and cured as described in Example 23.
[0222] Once cured, the films were removed and the mechanical
properties, that is, modulus and stress at break and strain at
break; swelling after being submerged in tetrahydrofuran (THF) for
24 hours calculated by weight, and extractables in the THF for each
cured copolymer were determined. The results, together with those
for Example 23 are set forth in Table 11.
14TABLE 11 Stress at Strain at Swelling Modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 26 1.51 2.12 180 250
8.4 46 0.68 1.54 294 418 10.5 47 0.54 0.81 343 540 6.8 48 0.22 0.62
882 1260 21
[0223] The data in Table 11 demonstrates that as molecular weight
of the polydimethylsiloxane increased, the modulus and stress at
break decreased while the strain at break increased. Increasing
molecular weight of the diamine also inhibited cure somewhat with
26% extractables when the diamine having a number average molecular
weight of 49,700 was used.
Examples 49-50
Example 49
[0224] In Example 49, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 29, except a mixture of 27.5
parts of methylenedicyclohexylene-4,4'-diisocyanate, 16.3 parts of
isocyanatoethyl methacrylate, and 56.3 parts of DAROCUR.TM. 1173
was fed at a rate of 0.105 g/min (0.000330 equivalents
isocyanate/min) into the first zone and Polydimethylsiloxane
Diamine D, Lot 1, molecular weight 35,700, was fed at a rate of 6.2
g/min (0.000164 mol/min) in to the sixth zone. The rheological
properties were as follows:
15 Storage modulus 3.1 .times. 10.sup.4 Pa Loss modulus 2.0 .times.
10.sup.4 Pa Crossover modulus 1.6 .times. 10.sup.4 Pa Crossover
temperature 65.degree. C. Shear creep viscosity 3.8 .times.
10.sup.4 Pa
Example 50
[0225] In Example 50, the polydimethylsiloxane oligourea segmented
copolymer prepared in Example 49 was exposed to 1.73 mW for 20
minutes low intensity ultraviolet irradiation as in Example 30. The
mechanical properties and the swelling, calculated by weight, and
extractables after immersion in tetrahydrofuran (THF) were as
follows:
16 Modulus 0.25 MPa Stress at break 0.46 MPa Strain at break 621%
Swelling 1050% Extractables 26%
Examples 51-54
Examples 51-52
[0226] In Example 51, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 31, except 105.52 parts (20.00
mmoles) Polydimethylsiloxane Diamine A molecular weight 5280, in
100.00 parts toluene, a mixture of 3.84 parts (15.74 mmoles) of
tetramethyl-m-xylylene diisocyanate and 1.24 parts (7.99 mmoles) of
isocyanatoethyl methacrylate in 15 parts toluene, and 20.00 parts
2-propanol were used.
[0227] In Example 52, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 51, except a mixture of 4.40
parts (18.00 mmoles) of tetramethyl-m-xylylene diisocyanate and
0.62 parts (3.99 mmoles) of isocyanatoethyl methacrylate in 15
parts toluene was used.
[0228] The polydimethylsiloxane oligourea segmented copolymers of
Examples 51 and 52 had degrees of polymerization of 5 and 10,
respectively.
[0229] The storage modulus, G', loss modulus, G", crossover
modulus, and crossover temperature were determined for Examples 51
and 52. The shear creep viscosity could not be measured for these
copolymers as they were above the limit of the test instrument. The
results are set forth in Table 12.
17TABLE 12 Crossover Crossover G' at 25.degree. C. G" at 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 51 33 .times.
10.sup.4 7 .times. 10.sup.4 30 .times. 10.sup.4 115 52 100 .times.
10.sup.4 20 .times. 10.sup.4 .about.0.1 .times. 10.sup.4 163
[0230] The data in Table 12 demonstrates that as the average degree
of oligomerization increased from 5 to 10, the loss modulus
increased and the crossover modulus decreased.
Examples 53-54
[0231] In Examples 53-54, using the second portion samples of
Examples 51-52, respectively, and the copolymers were subjected to
1.73 mW for 20 minutes low intensity ultraviolet radiation to
effect cure. The rheological characteristics were as set forth in
Table 13.
18TABLE 13 Stress at Strain at Swelling Modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 53 4.70 1.69 160 390
20.2 54 4.97 1.38 190 .about.600 45
[0232] The copolymers were curable, but as the average degree of
oligomerization increased the cure was less efficient, as indicated
by the high content of extractables.
Examples 55-56
[0233] In Example 55 a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 51, except a mixture of 4.19
parts (16.00 mmoles) of methylenedicyclohexylene-4,4'-diisocyanate
and 1.24 parts (8.00 mmoles) of isocyanatoethyl methacrylate in 15
parts toluene was used.
[0234] In Example 56, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 31, except a mixture of 4.72
parts (18.00 mmoles) of methylenedicyclohexylene-4,4'-diisocyanate
and 0.62 parts (4.00 mmoles) of isocyanatoethyl methacrylate in 15
parts toluene was used.
[0235] The copolymers of Examples 55-56 had average degrees of
polymerization of 5 and 10, respectively. The storage modulus, G',
the loss modulus, G", the crossover temperature, and the shear
creep viscosity of the copolymers of Examples 55 and 56, together
with those of Example 20 that was prepared using the same reactants
but in proportions such that the degree of oligomerization was 3,
are set forth in Table 14.
19TABLE 14 Shear creep Ex- G' at G" at Crossover Crossover
viscosity at am- 25.degree. C. 25.degree. C. Modulus Temp.
25.degree. C. ple (Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)*
20 1.7 .times. 10.sup.4 3.0 .times. 10.sup.4 5.0 .times. 10.sup.4 6
5.7 .times. 10.sup.3 (1 Pa) 55 12.0 .times. 10.sup.4 8.0 .times.
10.sup.4 7.0 .times. 10.sup.4 36 2.8 .times. 10.sup.3 (1 Pa) 56
27.0 .times. 10.sup.4 9.0 .times. 10.sup.4 5.0 .times. 10.sup.4 83
7.3 .times. 10.sup.6 (6 kPa) *300 seconds shear time; shear stress
as indicated in parenthesis
[0236] The data in Table 14 demonstrate that as the average degree
of oligomerization increased, G', G", and the crossover,
temperature increased, and the shear creep viscosity dramatically
increased.
Examples 57-58
[0237] In Examples 57-58, using the second portion samples of
Examples 55-56, respectively, and each of the copolymers was
subjected to 1.73 mW of low intensity ultraviolet radiation for 20
minutes to effect cure. The rheological characteristics of the
copolymers of Examples 57-58 together with those of Example 26 that
was prepared using the same reactants but achieving an average
degree of oligomerization of 3, are set forth in Table 15.
20TABLE 15 Stress at Strain at Swelling Modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 26 1.51 2.12 180 250
8.4 57 0.77 1.81 310 407 22.3 58 0.50 0.31 870 dissolved
dissolved
[0238] The data in Table 15 demonstrate the average degree of
oligomerization increased, the copolymer was more difficult to cure
as indicated by the increased percent swelling in THF and percent
extractables from the copolymer of Example 26 to the copolymer of
Example 57 and the fact that the copolymer of Example 58 dissolved
in the THF.
Examples 59-64
Examples 59-61
[0239] In Example 59, 99.6 parts Polydimethylsiloxane Diamine D,
Lot 2, molecular weight 37,800, and 0.4 parts ESACURE.TM. KB1, a
photoinitiator, available from Sartomer Company, Exton, Pa., were
fed at a rate of 3.58 g/min (0.000189 equivalents amine/min) into
the first zone of an 18 mm counter-rotating twin screw extruder
available from Leistritz Corporation, Allendale, N.J.). A mixture
of 45.8 parts by weight methylene dicyclohexylene-4,4'-diisocyanate
and 54.2 parts by weight isocyanatoethyl methacrylate was fed at a
rate of 0.0266 g/min (0.000186 equivalents isocyanate/min) into the
fourth zone. The extruder had a 40:1 length:diameter ratio and
double-start fully intermeshing screws throughout the entire length
of the barrel, rotating at 100 revolutions per minute. The
temperature profile of the each of the 90 mm long zones was: zone 1
to 4--50.degree. C.; zone 5--90.degree. C.; zone 6--170.degree. C.,
zone 7--180.degree. C.; zone 8-100.degree. C.; and
endcap--90.degree. C. Zone seven was vacuun vented. The resultant
extrudate was cooled in air and collected.
[0240] In Example 60, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 59, except a mixture of 77.2
parts by weight methylene dicyclohexylene-4,4'-diisocyanate and
22.8 parts by weight isocyanatoethyl methacrylate was fed at a rate
of 0.0252 g/min (0.000185 equivalents isocyanate/min) into zone
4.
[0241] In Example 61, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 59, except a mixture of 83.5
parts by weight methylene dicyclohexylene-4,4'-diisocyanate and
16.5 parts by weight isocyanatoethyl methacrylate was fed at a rate
of 0.0249 g/min (0.000185 equivalents isocyanate/min) into zone 4,
zone 6 was at 180.degree. C., and zone 8 and endcap were at
150.degree. C.
[0242] The copolymers of Examples 59-61 had degrees of
polymerization of 2, 5 and 7, respectively. The storage modulus,
G", loss modulus, G", crossover modulus, crossover temperature, and
shear creep viscosity at 25.degree. C. were determined for Examples
59-61 and, together with those of Example 49 that was prepared from
the same reactants but had an average degree of oligomerization of
3, are set forth in Table 16.
21TABLE 16 Shear creep Ex- G' at G" at Crossover Crossover
viscosity at am- 25.degree. C. 25.degree. C. Modulus Temp.
25.degree. C. ple (Pa) (Pa) (Pa) (.degree. C.) (Pa .multidot. s)*
59 0.8 .times. 10.sup.4 0.9 .times. 10.sup.4 1.0 .times. 10.sup.4
18 4.6 .times. 10.sup.4 (1 Pa) 49 3.1 .times. 10.sup.4 2.0 .times.
10.sup.4 1.6 .times. 10.sup.4 65 3.8 .times. 10.sup.4 (1 Pa) 60 6.0
.times. 10.sup.4 1.8 .times. 10.sup.4 1.8 .times. 10.sup.4 104 2.2
.times. 10.sup.6 (20 Pa) 61 7.2 .times. 10.sup.4 1.8 .times.
10.sup.4 1.9 .times. 10.sup.4 133 1.8 .times. 10.sup.7 (20 Pa) *300
seconds shear time; shear stress as marked
[0243] The data in Table 16 demonstrate that as the average degree
of oligomerization increased, the shear creep viscosity, storage
modulus, crossover modulus and temperature increased.
Examples 62-64
[0244] In Examples 62-64, 0.5 parts DAROCUR.TM. 1173 was added to
100 parts the polydimethylsiloxane oligourea segmented copolymers
of Examples 59-61, respectively, and the copolymers were subjected
to 1.73 mW for 20 minutes low intensity radiation to cure the
copolymers. The copolymer of Example 64 did not cure. The modulus,
stress at break, strain at break, THF swelling calculated by
weight, and THF extractables for Examples 62-63 and Example 50 are
set forth in Table 17.
22TABLE 17 Stress at Strain at Swelling modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 62 0.27 0.71 572 800
16 50 0.25 0.46 621 1050 26 63 0.2 0.22 868 2200 45
[0245] The data in Table 17 demonstrates that as the average degree
of oligomerization increased, the stress at break decreased and the
strain at break increased. Also as the average degree of
oligomerization increased for these high molecular weight
polydimethylsiloxane diamines, the percent extractables also
increased, indicating diminished curewith no cure occurring at an
average degree of oligomerization of 7.
Examples 65-69
Examples 65-67
[0246] In Example 65, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 17, except a mixture of 3.25
parts (13.33 mmoles) of tetramethyl-m-xylylene diisocyanate and
1.85 parts (13.33 mmoles) of vinyl dimethyl azlactone available
from S.N.P.E. Chemicals, Princeton, N.J., in 15 parts toluene was
added dropwise to a solution of 105.52 parts (20.00 mmoles)
Polydimethylsiloxane Diamine A molecular weight 5280 in 112 parts
toluene, and then 15 parts 2-propanol was added.
[0247] In Example 66, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 17, except a mixture of 3.25
parts (6.67 mmoles) of tetramethyl-m-xylylene diisocyanate, and
2.68 parts (6.67 mmoles) of
m-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate in 15 parts
toluene was added dropwise to a solution of 105.52 parts (10.00
mmoles) of Polydimethylsiloxane Diamine A molecular weight 5280 in
112 parts toluene, and then 15 parts 2-propanol was added.
[0248] In Example 67, 50 parts of the polydimethylsiloxane
oligourea segmented copolymer of Example 29 was blended with 50
parts of the polydimethylsiloxane oligourea segmented copolymer of
Example 66.
[0249] The average degree of oligomerization of each of the
copolymers of Examples 65-67 was 3. The storage modulus, G', loss
modulus, G", crossover modulus and crossover temperature were
determined for these Examples. The shear creep viscosity was beyond
the limits of the test equipment. The results are set forth in
Table 18.
23TABLE 18 Crossover Crossover G' at 25.degree. C. G" at 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 65 100
.times. 10.sup.4 10 .times. 10.sup.4 20 .times. 10.sup.4 132 66 70
.times. 10.sup.4 30 .times. 10.sup.4 20 .times. 10.sup.4 127 67 70
.times. 10.sup.4 20 .times. 10.sup.4 8 .times. 10.sup.4 125
[0250] The data in Table 18 shows little difference in the
copolymers of Examples 65-67, the differences in the copolymers
being only in the terminal groups.
Examples 68 and 69
[0251] In Examples 68 and 69, 0.5 part DAROCUR.TM. 1173 was added
to the copolymers of Examples 65 and 67, respectively, and the
copolymer of Example 68 was subjected to 1.73 mW for 20 minutes
ultraviolet irradiation while the copolymer of Example 69 was
subjected to 1.73 mW for 60 minutes ultraviolet irradiation to
effect free-radical polymerization. The copolymner of Example 66,
compounded with 0.5 parts DAROCUR.TM. 1173, did not homopolymerize
when irradiated as in Example 69 possibly due to steric hindrance.
The mechanical properties are set forth in Table 19:
24TABLE 19 Stress at Strain at Swelling Modulus break break in THF
Extractables Example (MPa) (MPa) (%) (%) (%) 68 6.31 1.75 111 285
9.5 69 4.03 1.35 120 317 12.7
[0252] The data in Table 19 shows that a polydimethylsiloxane
oligourea segmented copolymer incapable of homopolymerization was
copolymerized with other free radically polymerizable
polydimethylsiloxane oligoureas and formed a mixed copolymer.
Examples 70-71
Example 70
[0253] In Example 70, a polydiorganosiloxane oligourea segmented
polymer was prepared as in Example 17, except that 100.27 parts
(10.4 mmoles) Polydiphenyldimethsiloxane Diamine F, molecular
weight 9,620 dissolved in 94 parts toluene was substituted for
Diamine A, and a mixture of 1.82 parts (6.95 mmoles) of
methylenecyclohexylene-4,4'-diisocyanate and 1.08 parts (6.95
mmoles) of isocyanatoethyl methacrylate was used. The copolymer of
this Example had a degree of oligomerization of 3. The rheological
properties were as follows:
25 Storage modulus 2.8 .times. 10.sup.4 Pa Loss modulus 2.8 .times.
10.sup.4 Pa Crossover modulus 2.8 .times. 10.sup.4 Pa Crossover
temperature 25.degree. C.
Example 71
[0254] In Example 71, 0.5 parts DAROCUR.TM. 1173 was added to the
copolymer of Example 70 and the copolymer was subjected to 1.73 mW
for 20 minutes low intensity radiation to effect curing. The
mnechanical properties, swelling in tetrahydrofuran (THF) and THF
extractables were as follows:
26 Modulus 0.87 MPa Stress at break 1.37 MPa Strain at break 203%
Swelling in THF 330% THF extractables 13%
Example 72
[0255] In Example 72, a mixture of 99 parts by weight
Polydimethylsiloxane Diamine C, Lot 2, molecular weight 22,300, and
1 part by weight VAZO.TM. 64, a thermal initiator available from
DuPont Co., was fed into the sixth zone of an 18 mm co-rotating
twin screw extruder having a 40:1 length:diameter ratio (available
from Leistritz Corporation, Allendale, N.J.) at a rate of 6.24
g/min (0.000560 equivalents amine/min). A mixture of 62 parts by
weight tetramethyl-m-xylyene diisocyanate and 38 parts by weight
isocyanatoethyl methacrylate was fed into the sixth zone at a rate
of 0.0645 g/min (0.000486 equivalents isocyanate/min). The feed
line of this stream was placed close to the screw threads. The
extruder had double-start fully intermeshing screws throughout the
entire length of the barrel, rotating at 75 revolutions per minute.
The temperature for the entire extruder and endcap was set at a
40.degree. C. The material sat at room temperature for 197 days
without curing; consequently the VAZO.TM. 64 initiator became
ineffective. More initiator was added to the copolymer by kneading
in 1 part by weight VAZO.TM. 64 to 100 parts by weight copolymer.
The copolymer was cured for 20 minutes in water at 100.degree. C.
The cured copolymer was submerged in tetrahydrofuran for 24 hours
and swelled 930% by volume.
Examples 73-77
Examples 73-75
[0256] In Example 73, 50 parts (9.47 mmoles) Polydimethylsiloxane
Diamine A molecular weight 5280, was degassed in a 250 mL round
bottom flask and 150 parts dichloromethane was added and mixed
well. Next, 1.38 parts (6.24 mmoles) aminopropyl triethoxysilane
(APS) was added with stirring. Finally, 3.08 parts (12.62 mmoles)
tetramethyl-m-xylylene diisocyanate was added and the solution was
mixed for 20 minutes. The polydimethylsiloxane oligourea segmented
copolymer solution was poured into an aluminum tray and stood at
room temperature until the solvent evaporated.
[0257] In Example 74, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 73, except 1.19 parts (6.23
mmoles) of aminopropyl methyl diethoxysilane (APMS) was substituted
for the aminopropyl triethoxysilane.
[0258] In Example 75, a polydimethylsiloxane oligourea segmented
copolymer was prepared as in Example 73, except 1.54 parts (6.23
mmoles) of isocyanatopropyl triethoxysilane (IPS) was substituted
for the aminopropyl triethoxysilane, and 1.53 parts (6.27 mmoles)
of tetramethyl-m-xylylene diisocyanate was used.
[0259] The storage modulus, G', the loss modulus, G", and crossover
temperature were determined for Examples 73-75. The crossover
modulus was determined for Examples 73 and 75, but was not
determinable for Example 74. The results are set forth in Table
20.
27TABLE 20 Crossover Crossover Capping G' at 25.degree. C. G" at
25.degree. C. Modulus Temp. Example agent (Pa) (Pa) (Pa) (.degree.
C.) 73 APS 300 .times. 10.sup.4 12 .times. 10.sup.4 25 .times.
10.sup.4 165 74 APMS 300 .times. 10.sup.4 80 .times. 10.sup.4 --
>170 75 IPS 50 .times. 10.sup.4 20 .times. 10.sup.4 0.4 .times.
10.sup.4 150
Examples 76-77
[0260] In Examples 76-77, to 100 parts of each of the copolymers of
Examples 74-75, respectively, was added 1.25 parts trichloroacetic
anhydride, and the solution was subsequently air dried on polyester
release liner. These samples were cured for 14 days at 22.degree.
C. The cured copolymers of Examples 76 and 77 were submerged in THF
for 24 hours and swelled 340 and 290 percent by volume,
respectively.
Examples 78-83
Examples 78-80
[0261] In Example 78, a mixture of 32.9 parts by weight
tetramethyl-m-xylylene diisocyanate, 32.2 parts by weight
isocyanatopropyl triethoxysilane, 33.8 pairs by weight octyl
triethoxy silane, and 1.0 parts by weight dibutyl tin dilaurate was
fed into the fifth zone of an 18 mm counter-rotating twin screw
extruder having a 40:1 length:diameter ratio (available from
Leistritz Corporation, Allendale, N.J.) at a rate of 0.823 g/min
(0.00331 equivalents isocyanate/min). The feed line of this stream
was placed close to the screw threads. Polydimethylsiloxane Diamine
A molecular weight 5,280, was added the fifth zone at a rate of
8.61 g/min (0.00326 equivalents amine/min). The extruder had
double-start fully intermeshing screws throughout the entire length
of the barrel, rotating at 50 revolutions per minute. The
temperature profile for each of the 90 mm long zones was: zones 1
through 4--30.degree. C.; zone 5--40.degree. C.; zone 6--80.degree.
C.; zone 7--90.degree. C.; zone 8--130.degree. C.; and
endcap--140.degree. C. Zone seven was vacuum vented to remove
entrained air. The resultant polydimethylsiloxane oligourea
segmented copolymer was extruded and samples were immediately
pressed and cured for one week at 22.degree. C., 50% relative
humidity.
[0262] In Example 79, a mixture of 32.9 parts by weight
tetramethyl-m-xylylene diisocyanate, 32.2 parts by weight
isocyanatopropyl triethoxysilane, 33.8 parts by weight
octyltriethoxy silane, and 1.0 parts by weight dibutyl tin
dilaurate was fed into the fifth zone of an 18 mm counter-rotating
twin screw extruder having a 40:1 length:diameter ratio (available
from Leistritz Corporation, Allendale, N.J.) at a rate of 0.387
g/min (0.00155 equivalents isocyanate/min). The feed line of this
stream was placed close to the screw threads. Polydimethylsiloxane
Diamine B, molecular weight 10,700, was added the fifth zone at a
rate of 8.65 g/min (0.00162 equivalents amine/min). The extruder
had double-start fully intermeshing screws throughout the entire
length of the barrel, rotating at 50 revolutions per minute. The
temperature profile for each of the 90 mm long zones was: zones 1
through 4--30.degree. C.; zone 5--40.degree. C.; zone 6--80.degree.
C.; zone 7--90.degree. C.; zone 8 and endcap--120.degree. C. Zone
seven was vacuum vented to remove entrained air. The resultant
polydimethylsiloxane oligourea segmented copolymer was extruded and
collected.
[0263] In Example 80, a mixture of 32.9 parts by weight
tetramethyl-m-xylylene diisocyanate, 32.2 parts by weight
isocyanatopropyl triethloxysilane, 33.8 parts by weight
octyltriethoxy silane, and 1.0 parts by weight dibutyl tin
dilaurate was fed into the fifth zone of an 18 mm counter-rotating
twin screw extruder having a 40:1 length:diameter ratio (available
friom Leistritz Corporation, Allendale, N.J.) at a rate of 0.2171
g/min (0.000872 equivalents isocyanate/min). Tlhe feed line of this
stream was placed close to the screw threads. Polydimethylsiloxane
Diamine C, molecular weight 22,300, was added the fifth zone at a
rate of 8.62 g/min (0.000773 equivalents amine/min). The extruder
had double-start fully intermeshing screws throughout the entire
length of the barrel, rotating at 50 revolutions per minute. The
temperature profile for each of the 90 mm long zones was: zones 1
through 4--30.degree. C.; zone 5--40.degree. C.; zone 6--80.degree.
C.; zone 7--90.degree. C.; zone 8 and endcap--120.degree. C. Zone
seven was vacuum vented to remove entrained air. The resultant
polymer was extruded and collected.
[0264] Each of the copolymers of Examples 78-80 was tested for the
storage modulus, G', the loss modulus, G", and crossover
temperature within three hours of extrusion. The crossover modulus
was determined for Examples 79 and 80, but was not determinable for
Example 78. The results are set forth in Table 22.
28TABLE 22 Crossover Crossover G' at 25.degree. C. G" at 25.degree.
C. Modulus Temp. Example (Pa) (Pa) (Pa) (.degree. C.) 78 24 .times.
10.sup.4 5.0 .times. 10.sup.4 -- >180 79 10 .times. 10.sup.4 5.0
.times. 10.sup.4 0.03 .times. 10.sup.4 145 80 10 .times. 10.sup.4
3.0 .times. 10.sup.4 0.2 .times. 10.sup.4 130
Examples 81-83
[0265] In Examples 81-83, copolymers prepared in Examples 78-80,
respectively, were pressed immediately after extrusion and cured
for one week at 22.degree. C., 50% relative humidity. The
copolymers were tested for mechanical properties and swelling in
THF, calculated by volume. The results of mechanical testing are
set forth in Table 23.
29TABLE 23 Stress at Strain at Modulus break break Swelling in
Example (MPa) (MPa) (%) THF (%) 81 4.82 1.39 110 430 82 1.90 0.81
180 680 83 1.17 0.89 370 900
[0266] As can be seen from the data in Table 23, as the molecular
weight of the polydimethylsiloxane diamine increased, the modulus
and stress at break decreased and the strain at break increased.
Also as the diamine molecular weight increased, swelling increased
indicating lower crosslink density.
Examples 84-85
Example 84
[0267] In Example 84, a mixture of 32.9 parts by weight
tetramethyl-m-xylylene diisocyanate, 32.2 parts by weight
isocyanatopropyl triethoxysilane, 33.8 parts by weight octyl
triethoxysilane, and 1.0 parts by weight dibutyl tin dilaurate was
fed into the fifth zone of an 18 mm counter-rotating twin screw
extruder having a 40:1 length:diameter ratio (available fron
Leistritz Corporation, Allendale, N.J.) at a rate of 0.398 g/min
(0.00160 equivalents isocyanate/min). The feed line of this stream
was placed close to the screw threads. 75 parts by weight
Polydimethylsiloxane Diamine B, molecular weight 10,700, was mixed
with 25 parts by weight Polydiphenyldimethylsiloxane Diamine F,
molecular weight 9,620; the number average molecular weight of this
mixture was 10,400. This diamine mixture was fed into the fifth
zone of the extruder at a rate of 8.72 g/min (0.00169 equivalents
amine/min). The extruder had double-start fully intermeshing screws
throughout the entire length of the barrel, rotating at 50
revolutions per minute. The temperature profile for each of the 90
mm zones was: zones 1 through 4--30.degree. C.; zone 5--35.degree.
C.; zone 6--80.degree. C.; zone 7--90.degree. C.; zones 8 and
endcap--120.degree. C. Zone seven was vacuum vented to remove
entrained air. The resultant polymer was extruded, collected and
tested within three hours for rheological properties. The results
were as follows:
30 Storage modulus 10 .times. 10.sup.4 Pa Loss modulus 2.4 .times.
10.sup.4 Pa Crossover modulus none Crossover temperature
>180.degree. C.
Example 85
[0268] In Example 85, the copolymer prepared in Example 84 was
pressed immediately after extrusion and cured for one week at
22.degree. C., 50% relative humidity. The copolymers were tested
for mechanical properties and swelling in THF, calculated by
volume. The properties were as follows:
31 Modulus 1.6 MPa Stress at break 0.77 MPa Strain at break 740
Swelling 103%
Examples 86-88
[0269] In Example 86, Polydimethylsiloxane Diamine A, Lot 1,
molecular weight 5280, was injected at a rate of 147 g.min (0.0279
mol/min) into zone 8 of a Berstorff 40 mm diameter, 1600 mm length
co-rotating extruder. Tetramethyl-m-xylylene diisocyanate was
injected into zone 9 at a rate of 7.11 g/min (0.0291 mol/min). The
screws rotated at 100 revolutions per minute. The temperatures of
the individual zones were: zones 1 through 7 (not used); zone
8--60.degree. C., zone -9--120.degree. C., zone 10 and
encap--180.degree. C. The material was extruded into a strand,
cooled in a liquid bath, and pelletized.
[0270] 20 grams of the UV-curable composition of Example 20, 20
grams of polydimethylsiloxane polyurea segmented copolymer (as
prepared above) and 20 grams toluene/isopropanol 50/50 mixture were
agitated until a homogeneous solution was made. The sample was air
dried.
[0271] In Example 87, Polydimethylsiloxane Diamine A, Lot 1,
molecular weight 5280, was injected at a rate of 169 g.min (0.0318
mol/min) into zone 8 of a Berstorff 40 mm diameter, 1600 mm length
co-rotating extruder. Methylenedicyclohexylene-4,4'-diisocyanate
was injected into zone 9 at a rate of 8.33 g/min (0.0318 mol/min).
The screws rotated at 100 revolutions per minute. The temperatures
of the individual zones were: zones 1 through 7 (not used); zone
8--60.degree. C., zone 9--120.degree. C., zone 10 and
encap--180.degree. C. The material was extruded into a strand,
cooled in a liquid bath, and pelletized.
[0272] 20 grams of the UV-curable composition of Example 20, 20
grams of polydimethylsiloxane polyurea segmented copolymer (as
prepared above) and 20 grams toluene/isopropanol 50/50 mixture were
agitated until a homogeneous solution was made. The sample was air
dried.
[0273] In Example 88, a blend UV-curable polydiorganosiloxane
oligourea segmented copolymer and non-curable polydiorganosiloxane
polyurea segmented copolymer was made analogously as in Example 86,
except 20 grams of UV-curable composition of Example 20 was
substituted with 20 grams polydiorganosiloxane oligourea segmented
copolymer of Example 29.
[0274] The storage modulus, G', loss modulus, G" (at 25.degree.
C.), crossover modulus, and crossover temperature were determined
for the uncured blends of UV curable polydiorganosiloxane oligourea
segmented copolymers with polydiorganosiloxane polyurea segmented
copolymers of Examples 86-88. The results are set forth in Table
24.
32 TABLE 24 Ex. 86 Ex 87 Ex. 88 G' 7.8 .times. 10.sup.5 Pa 1.4
.times. 10.sup.5Pa 3.0 .times. 10.sup.5 Pa G" 1.2 .times. 10.sup.5
Pa 5.8 .times. 10.sup.4 Pa 3.0 .times. 10.sup.4 Pa crossover
modulus 2.1 .times. 10.sup.5 Pa 8.9 .times. 10.sup.2 Pa
undeterminable crossover temperaturer 112.degree. C. 142.degree. C.
above 170.degree. C.
[0275] Dried portions of the samples of Examples 86, 87, and 88
were pressed, cured and tested for mechanical properties,
swellability in the THF, and extractability in the THF, as
described in Example 23. The results are set forth in Table 25
33 TABLE 25 Ex. 86 Ex. 87 Ex. 88 Modulus [MPa] 3.44 1.18 4.67
Stress at break [MPa] 1.71 1.50 1.69 Strain at break 230% 290% 200%
Swellability 1700% 1200% 1300% Extractables 54% 37% 42%
Example 89
[0276] In Example 89, a blend of equal parts of the compositions of
Example 20, Example 43, Example 44, and Example 59 was made in a
50/50 toluene/isopropanol mixture, and subsequently dried in
air.
[0277] The storage modulus, G', loss modulus, G" (at 25.degree.
C.), crossover modulus, and crossover temperature were determined
for the uncured portion of the sample. The results are set forth in
Table 24.
34 TABLE 26 G' 8.0 .times. 10.sup.3 Pa G" 1.0 .times. 10.sup.4 Pa
crossover modulus 1.7 .times. 10.sup.4 Pa crossover temperature
12.degree. C.
[0278] A portion of the sample was pressed, cured, and
characterized as in Example 86, and the results are presented
below.
35 Ex. 89 Modulus [MPa] 0.55 Stress at break [MPa] 1.38 Strain at
break 308% Swellability 800% Extractables 10%
Example 90
[0279] In Example 90, 0.30 grams , 1,12-diaminedodecane (Available
from Aldrich Chemical), and 100.0 grams Polydimethylsiloxane
Diamine D, Lot 2 was dissolved in 100 grams of a 50/50
toluene/isopropanol mixture. To the solution was added dropwise a
mixture of 0.46 grams isocyanatoethylmethacrylate and 0.72 grams
tetramethyl-m-xylylene diisocyanate in 20 grams toluene/isopropanol
(50/50) mixture. To the solution was added 1.0 gram DAROCUR.TM.
1173, and the resulting mixture was dried in air to form a white,
viscous fluid. One part of the uncured polymer was used to test
rheological properties as described in Example 86, and the results
are presented below.
36 Storage Modulus at 25.degree. C. 1.1 .times. 10.sup.1 Pa Loss
Modulus at 25.degree. C. 2.4 .times. 10.sup.2 Pa Crossover Modulus
undetermined Crossover Temperature below -30.degree. C.
[0280] A portion of the dried polymer was pressed, cured, and
tested as described in Example 86
37 Modulus [MPa] 0.13 Stress at break [MPa] 0.21 Strain at break
377% Swelling in THF 1210% Extractables 40.0%
Example 91
[0281] In Example 91, 1.9 grams 1,12-diaminedodecane, and 100.0
grams Polydimethylsiloxane Diamine A, lot 1 was dissolved in 100
grams of a 50/50 toluene/isopropanol mixture. To the solution was
added dropwise a mixture of 2.94 grams isocyanatoethylmethacrylate
and 4.62 grams tetramethyl-m-xylylene diisocyanate in 20 grams of a
toluene/isopropanol 50/50 mixture. To the solution was added 1.0
gram DAROCUR.TM. 1173, and the resulting mixture was dried in air
to form a hazy, semisolid. One part of the uncured polymer was used
to test rheological properties as described in Example 86.
38 Storage Modulus at 25.degree. C. 2.0 .times. 10.sup.5 Pa Loss
Modulus at 25.degree. C. 9.3 .times. 10.sup.4 Pa Crossover Modulus
8.3 .times. 10.sup.4 Pa Crossover Temperature 40.degree. C.
[0282] A portion of the dried polymer was pressed, cured, and
tested as described in Example 86.
39 Modulus [MPa] 6.26 Stress at break [MPa] 1.73 Strain at break
100% Swelling in THF 317% Extractables 13.3%
Example 92
[0283] In Example 92, 0.96 grams Polyamine IH1000 (available from
Air Products and Chemicals, Inc.), and 100.0 grams
Polydimethylsiloxane Diamine D, Lot 2 was dissolved in 100 grams of
a toluene/isopropanol 50/50 mixture. To the solution was added
dropwise a mixture of 0.46 grams isocyanatoethylmethacrylate and
0.72 grams tetramethyl-m-xylylene diisocyanate in 20 grams
toluene/isopropanol (50/50) mixture. To the solution was added 1.0
gram DAROCUR.TM. 1173, and the resulting mixture was dried in air
to form white, very viscous fluid. One part of the polymer was used
to test rheological properties as described in Example 86.
40 Storage Modulus at 25 C. 1.3 .times. 10.sup.2 Pa Loss Modulus at
25 C. 9.8 .times. 10.sup.2 Pa Crossover Modulus 1.0 .times.
10.sup.4 Pa Crossover Temperature -30.degree. C.
[0284] A portion of the dried polymer was pressed, cured, and
tested as described in Example 86.
41 Modulus [MPa] 0.21 Stress at break [MPa] 0.62 Strain at break
516% Swelling in THF 1027% Extractables 20.3%
Example 93
[0285] In Example 93, 5.24 grams tetramethyl-m-xylylene
diisocyanate was charged to a 500 ml flask in 10 milliliters of
dichloromethane. To this was added 31.7 grams of Jeffamine D-2000,
and the sample was well mixed. Next was added a solution of 61.4
grams of PDMS Diamine A, Lot 1 in 40 ml dichloromethane. Next, 1.66
grams isocyanatoethylmethacrylate was added and the solution was
mixed for 15 minutes, followed by the addition of 1.1 grams
DAROCUR.TM. 1173. The mixture was allowed to dry on a liner in the
dark to form blueish, somewhat inhomogeneous semisolid.
[0286] One part of the uncured polymer was used to test rheological
properties as described in Example 86.
42 Storage Modulus at 25.degree. C. 1.6 .times. 10.sup.5 Pa Loss
Modulus at 25.degree. C. 6.8 .times. 10.sup.4 Pa Crossover Modulus
5.5 .times. 10.sup.4 Pa Crossover Temperature 55.degree. C.
[0287] Dried polymer was pressed at 90.degree. C. into approx. 1
millimeter film between two liners and exposed to low intensity UV
lights for 20 minutes, and tested as described in Example 86.
43 Modulus [MPa] 4.38 Stress at break [MP] 1.04 Strain at break
218% Swelling in THF 430% Extractables 14.1%
Example 94
[0288] In Example 94, a Berstorff 25 mm diameter co-rotating twin
screw extruder having a 29.5:1 length diameter ratio was used with
a dual injection port at zone 1 and a single injection port at both
zones 3 and 4. Double start fully intermeshing screws, rotating at
125 revolutions per minute, were used throughout the entire length
of the barrel with 2 sets of 25 mm length kneading blocks located
at the end of zone 5. The temperature profile for each of the zones
was: zone 1--30.degree. C.; zone 2--75.degree. C.; zone
3--100.degree. C.; zone 4--125.degree. C.; zone 5--150.degree. C.;
zone 6--175.degree. C.; endcap--190.degree. C.;
meltpump--200.degree. C.; and necktube--230.degree. C. The
feedstock reagents were maintained under a nitrogen atmosphere. A
blend of 98 parts by weight Polydimethylsiloxane Diamine A, Lot 2,
molecular weight 5310, and 2 parts by weight Polydimethylsiloxane
Monoamine C, molecular weight 12,121 was injected at a rate of
15.13 g/min (0.00280 mol/min) into the first part of zone 1 and
methylenedicyclohexylene-4,4'-diisocyanate (DESMODUR W, obtained
from Miles Laboratory) was injected at a rate of 29.59 g/min (0.113
mol/min) into the second part of zone 1. Jeffamine.TM. D-400
polyoxypropylenediamine (obtained from Huntsman Corporation,
molecular weight 466 g/mol for Lot #5C710) was injected at a rate
of 21.19 g/min (0.0455 mol/min) into zone 3. Dytek A.TM.
(2-methyl-1,5-pentanediamine obtained from DuPont, molecular weight
of 116 g/mol for Lot #SC950419J01)) was injected at zone 4 at a
rate of 8.33 g/min (0.0718 mol/min). The resultant
polydimethylsiloxane oligourea segmented copolymer of NCO:NH.sub.2
ratio 0.94:1, was extruded as a 2.5 mm diameter strand into a
Fluorinert.TM. dryice bath and pelletized to afford a product with
a bimodal distribution by GPC with an overall
M.sub.n=1.1.times.10.sup.5.
Example 95
[0289] In Example 95, a Berstorff 25 mm diameter co-rotating twin
screw extruder was used as in Example 94 with the following
modifications. The screw, operating at 100 revolutions per minute,
was constructed with double start fully intermeshing screws used in
combination with partially intermeshing screws with one set of 25
mm length kneading blocks located at the start of zone 4 and three
sets located at the end of zone 5. The temperature profile for each
of the zones was: zone 1--30.degree. C.; zone 2--75.degree. C.;
zone 3--100.degree. C.; zone 4--125.degree. C.; zone 5--150.degree.
C.; zone 6--175.degree. C.; endcap and meltpump--175.degree. C. and
necklube--190.degree. C. The feedstock reagents were maintained
under a nitrogen atmosphere. Polydimethylsiloxane Diamine A, Lot 1,
5280 molecular weight was fed at a rate of 4.85 g/min (0.000919
mol/min) into the first part of zone 1. A blend of 20 parts by
weight phenyl isocyanate (obtained from Matheson Coleman and Bell)
and 80 parts by weight methylenedicyclohexylene-1,4'-di- isocyanate
(DESMODUR W, obtained from Miles Laboratory Lot #D233-4-0751) was
fed at a rate of 12.81 g/min (0.0499 mol/min) into the second part
of zone 1. Jeffamine.TM. D-400 polyoxypropylenediamine (obtained
from Huntsman Corporation, titrated molecular weight 452 g/mol for
Lot #CP5131) was injected at 19.45 g/min (0.0430 mol/min) into zone
3. And Dytek A.TM. (2-methyl-1,5-pentanediamine obtained from
DuPont, titrated molecular weight 117 g/mol for Lot #SC94030211)
was injected at zone 4 at a rate of 0.689 g/min (0.00589 mol/min).
The resultant polydimethylsiloxane oligourea segmented copolymer of
NCO:NH.sub.2 ratio 1.00:1, was extruded as a strand to yield a
product with M.sub.n=3.3.times.10.sup.4by GPC analysis.
[0290] The various modifications and alterations of this invention
will be apparent to those skilled in the art without departing from
the scope and spirit of this invention and this invention should
not be restricted to that set forth herein for illustrative
purposes.
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