Integrated cross-linkers and amine functional siloxane scavengers for RTV silicone rubber compositions

The present invention relates to an alkoxy-functional one-component RTV silicone rubber composition having therein novel scavenger compounds. The novel scavenger compounds comprise multi-amine functional silanes and amine functional siloxanes which can be either pure scavengers or integrated cross-linker, scavengers.

BACKGROUND OF THE INVENTION 
The present invention relates to a one-component RTV silicone rubber 
composition, and more particularly, the present invention relates to an 
alkoxy-functional one-component RTV silicone rubber composition having 
therein amine-functional scavengers. 
One-component room-temperature vulcanizable silicone rubber compositions 
are well known. Such compositions disclosed in BRUNER, U.S. Pat. No. 
3,035,016 and CEYZERIAT, U.S. Pat. No. 3,133,891. These patents disclose 
acyloxy-functional one-component RTV (RTV in this application refers to 
room-temperature vulcanizable) silicone rubber compositions. By 
acyloxy-functional, it is meant that the cross-linking agent in the 
composition was an acyloxy-functional silane and more particularly, an 
acetoxy-functional silane such as methyltriacetoxy-silane. The composition 
is prepared by mixing in an anhydrous manner, a silanol-terminated 
diorganopolysiloxane polymer with the acyloxy-functional cross-linking 
agent and a metal condensation catalyst. The resulting mixture was then 
compounded with fillers and various other ingredients in a substantially 
anhydrous manner. When it was desired to cure the composition, the 
composition was exposed to atmospheric moisture wherein the acyloxy groups 
hydrolyzed to cross-link the polymer to form a silicone elastomer. Since 
the early times of the BRUNER, U.S. Pat. No. 3,035,016 composition there 
have been devised various other types of functional RTV compositions such 
as ketoxime-functional RTV compositions, amine-functional RTV 
compositions, alkoxy-functional RTV compositions and so forth. An example 
of an amine-functional one-component RTV silicone rubber composition is to 
be found, for instance, in NITZSCHE, et al, U.S. Pat. No. 3,032,528. This 
patent utilizes an amine-functional silane as a cross-linking agent and 
has the advantages that it is fast-curing and non-corrosive. Nevertheless, 
it does give off an objectionable odor upon curing and sometimes toxic 
by-products. 
One of the most advantageous types of one-component RTV compositions was 
the alkoxy-functional RTV composition. An example of such a composition is 
to be found in BEERS, U.S. Pat. No. 4,100,129. Such a composition gives 
off an alcohol by-product upon curing and as a result is substantially 
non-corrosive. Further, it does not give off objectionable odors upon 
curing and has many other advantageous properties. However, one of the 
disadvantages of the BEERS, U.S. Pat. No. 4,100,129 composition was the 
fact that it was not as shelf-stable as would be desired. That is, after 
prolonged storage of 6 months or more, it was found that the cure rate of 
the composition would be unnecessarily retarded. Various means were 
devised to preserve the shelf-stability of such a composition. However, 
all such means were not as successful as would be desired and necessitated 
additional steps in the preparation of the composition which increased the 
cost thereof. Another disadvantage of the BEERS, U.S. Pat. No. 4,100,129 
composition is it did not have as rapid a cure rate as would be desired. 
This was true even with the titanium chelate catalysts of the BEERS 
patent. Accordingly, it was highly desirable to develop an 
alkoxy-functional RTV composition; that is, a composition that would cure 
through the hydrolysis and cross-linking of alkoxy-groups in the base 
polymer and which composition would be shelf-stable and have a rapid cure 
rate. It is hypothesized and has been hypothesized that the reason the 
BEERS, U.S. Pat. No. 4,100,129 composition does not have a sufficiently 
rapid cure rate and is not shelf-stable, was the fact that even though the 
composition was prepared anhydrously or in a substantially anhydrous 
manner, there became incorporated in the composition various unbonded 
hydroxy groups. Such unbonded hydroxy groups entered the composition as a 
result of their presence in the base silanol-terminated 
diorganopolysiloxane polymer or in the filler or in the various 
ingredients that were added to the composition. It was postulated that as 
a result of the unbonded hydroxy groups in such compositions, such hydroxy 
groups hydrolyzed the alkoxy groups to convert them to hydroxy groups. As 
a result, when the composition was exposed to atmospheric moisture it 
would cure slowly sometimes and other times it might not even cure at all; 
as a result of the converted hydroxy groups not being able to react and 
cross-link with each other. It has been postulated that the longer the 
polymer was packaged and maintained prior to exposure to atmospheric 
moisture for the purpose of curing it, the more alkoxy-groups would be 
hydrolyzed by the unbonded hydroxy groups and the more the shelf-stability 
and the cure rate of the composition would degrade. A recent development 
in rectifying this phenomenon is to be found in the disclosure of WHITE, 
et al, Ser. No. 277,524, filed on June 16, 1981, now U.S. Pat. No. 
4,395,526 which discloses the use of scavengers and integrated 
cross-linker, scavengers for the purpose of reacting with unbonded hydroxy 
groups in the uncured RTV composition so as to preserve the 
shelf-stability and the cure rate of the RTV composition. Thus, it is 
disclosed in the foregoing WHITE, et al case, that there can be utilized 
in the composition a compound having a scavenging leaving group which is 
capable of readily and rapidly reacting with all unbonded hydroxy groups 
in the composition so as to render them useless or inactive for reacting 
with the alkoxy-groups in the base diorganopolysiloxane polymer. It is 
indicated in the WHITE, et al, case that such scavenging leaving groups 
can be either a pure scavenging compound or they can be present an 
integrated cross-linker, scavenger; that is, an integrated cross-linker, 
scavenger being one which has scavenging groups in it and also has alkoxy 
groups in it. Such a compound can react with the base silanol-terminated 
polymer to result in a polymer system or base polymer system having 
scavenging groups as well as having alkoxy-groups on the terminal silicon 
atoms of the base diorganopolysiloxane polymer. Accordingly, such 
end-cappers or integrated cross-linker, scavengers could be utilized to 
both end-cap the silanol-terminated polymer so as to produce a base 
polymer capable of cross-linking to form an RTV silicone rubber 
composition and also could be utilized to react with unbonded hydroxy 
groups in the composition so as to prevent such unbonded hydroxy groups 
from attacking and hydrolyzing the alkoxy groups in the system. It is 
indicated in the WHITE, et al, case that the scavenging leaving group can 
be an amine-functional group, both in the pure scavenger or in the 
integrated cross-linker, scavenger compound. Examples of such 
amine-functional scavengers and integrated cross-linker scavengers are 
given on page 21 of WHITE, et al, U.S. Pat. No. 4,395,526; such as, for 
instance, methyldimethoxymethylaminosilane, etc. It is disclosed in that 
patent, basically, that the integrated cross-linker, scavenger or pure 
scavenging compound has in the amine-functional group a single amine 
functionality, which can be utilized for the purposes of the WHITE, et al 
case. It has now been found unexpectedly that compounds having additional 
amine functionalities, siloxane amine compounds, can be utilized as 
scavenging compounds and as integrated cross-linker, scavengers. Such 
compounds react with unbonded hydroxy groups in the composition so as to 
preserve the shelf-stability and the cure rate of the alkoxy-functional 
RTV silicone rubber compositions. Such amine-functional compounds as 
disclosed by the instant case can be used as both pure scavengers or as 
integrated cross-linker, scavengers for the purpose of end-capping silanol 
terminated polymers to form the base polymer of an alkoxy-functional 
one-component RTV system having a rapid cure rate and good 
shelf-stability. 
It is one object of the present invention to provide for an 
alkoxy-functional RTV composition having good shelf-stability in which 
there is present an amine-functional scavenging compound. 
It is an additional object of the present invention to provide an 
alkoxy-functional one-component RTV silicone rubber composition having a 
rapid cure rate in which there is present a scavenging compound having an 
amine functionality for reacting with unbonded hydroxy groups. 
It is yet an additional object of the present invention to provide for 
scavenging compounds and integrated cross-linker, scavenging compounds for 
reacting and bonding with unbonded hydroxy groups in alkoxy-functional 
one-component RTV compositions in which in each hydrolyzable leaving group 
in the scavenging compound, there is more than one amine functionality. 
It is yet still an additional object of the present invention to provide a 
process for producing a shelf-stable, rapid-cure-rate one-component 
alkoxy-functional RTV composition in which there is present a scavenging 
compound or integrated cross-linker, scavenger compound having as a 
scavenging group an amine-functional group with more than one amine 
functionality in each such leaving group. These and other objects 
accomplished by means of the disclosure set forth herein below. 
SUMMARY OF THE INVENTION 
In accordance with the objects there is provided by the present invention a 
shelf-stable, fast-curing one-component RTV silicone rubber composition 
comprising, 
(A) an organopolysiloxane base polymer having a viscosity varying in the 
range of 100 to 1,000,000 centipoise at 25.degree. C. where the organo 
group is a monovalent hydrocarbon radical wherein in said base polymer the 
terminal silicon atoms in the polymer chain have bonded to them at lease 
one alkoxy group; 
(B) an effective amount of a condensation catalyst; and 
(C) an effective amount of a scavenging compound selected from the class 
consisting of 
(i) scavenging silanes of the formula, 
##STR1## 
wherein R.sup.1, R.sup.2 are individually selected from C.sub.1-13 
monovalent hydrocarbon radicals, R.sup.5 and R.sup.6 are individually 
selected from the class consisting of hydrogen and C.sub.1-8 monovalent 
hydrocarbon radicals, R.sup.4 is a C.sub.2-8 divalent hydrocarbon radical; 
z is a whole number, 0 or 1; a is a whole number that can vary from 1 to 
4; and the sum of a+z can vary from 1 to 4; and R.sup.3 is selected from 
the class consisting of hydrogen, C.sub.1-8 monovalent hydrocarbon 
radicals, and a radical of the formula, 
##STR2## 
wherein R.sup.8, R.sup.9 are individually selected from the class 
consisting of hydrogen and C.sub.1-8 monovalent hydrocarbon radivals and 
R.sup.7 is a C.sub.2-8 divalent hydrocarbon radical; and 
(ii) scavenger siloxanes of the formula, 
##STR3## 
where R.sup.1, R.sup.2 are as previously defined and A is a radical 
selected from the class consisting of simple amine radicals of the 
formula, 
##STR4## 
where R.sup.10, R.sup.11 are individually selected from hydrogen, 
C.sub.1-8 monovalent hydrocarbon radicals and multi-amine functional 
radicals of the formula, 
##STR5## 
where R.sup.3, R.sup.5, R.sup.6 and R.sup.4 are as previously defined; x 
varies in the range of 0.00 to 2.50; y varies in the range of 0.00 to 
2.50; w varies in the range of 0.05 to 1.5; and the sum of x+y+w varies in 
the range of 2.10 to 3.00. 
It should be noted that for the simple amine-functional groups such as the 
ones disclosed in WHITE, et al, U.S. Pat. No. 4,395,526 and in the instant 
case, the by-product given off for most of those leaving groups is a gas. 
Accordingly, such simple amine-functional scavenging compounds and 
integrated cross-linkers are highly desirable in the production of the 
alkoxy-functional one-component RTV systems of the WHITE, et al, case. 
Since, if the by-product of such scavenging leaving groups is a gas, then 
the gas can be easily removed when the compound reacts with unbonded 
hydroxy groups in the composition to bind them and render them inert to 
the alkoxy groups. Accordingly, it is desirable that the by-product of the 
scavenging leaving group be the gas or liquid at room temperature so that 
the by-product can be removed easily in the production of the RTV 
composition and particularly in the continuous production of the RTV 
composition as disclosed in CHUNG, et al, Ser. No. 427,895. 
The foregoing CHUNG, et al, Ser. No. 437,895, discloses the production of 
the WHITE, et al compositions in a substantially continuous manner in a 
devolatilizing extruder. 
The silanes of Formulas (1) and (2) can be either pure scavenging compounds 
or integrated cross-linkers. Preferably the siloxanes of Formula (2) are 
just integrated cross-linker, scavengers. 
It is desirable in many cases to remove the by-products since they may 
affect the desired properties of the cured RTV silicone rubber 
composition. Thus, a scavenging, leaving group by-product may affect the 
adhesion properties or the ultimate shelf-stability. However, it should be 
noted if such scavenging, leaving group by-products, whether gas, liquid 
or solid, do not affect the physical properties of the cured and uncured 
RTV silicone rubber composition or if they do affect such properties and 
it is not of importance to the desired end-use of the composition, then 
the particular amine-functional scavenger can be used to produce the 
composition. It is the purpose of the instant application to disclose 
scavengers and integrated cross-linker scavenging compounds having amine 
scavenging leaving groups whose by-products are gases, liquids or solids 
and which can be used in the compositions of WHITE, et al, U.S. Pat. No. 
4,395,526 and particularly when such compositions are produced in a 
devolatilizing extruder as disclosed in CHUNG, et al, Ser. No. 437,895. 
Thus, if the desired end-properties are affected by the by-product of the 
scavenging leaving group, then it may be desirable to use one of the 
amine-scavenging compounds which gives off a gas or liquid by-product, 
which gas or liquid by-products can be easily removed in a devolatilizing 
extruder. On the other hand, if the by-product of the scavenging leaving 
group does affect certain physical properties of the uncured and cured 
composition and such is not of importance to the use of the RTV silicone 
rubber composition, then any of the scavenging compounds or integrated 
cross-linker scavenging compounds of the instant case can be utilized to 
react with unbonded hydroxy groups in the composition. This is true of 
whether the by-product of the scavenging group is a liquid or a solid and 
irrespective of whether the composition is prepared continuously in a 
devolatilizing extruder or by some other means. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the compounds of Formulas (1) and (2), R.sup.1 and R.sup.2 are each 
individually selected from C.sub.1-13 monovalent hydrocarbon radicals. 
Thus, R.sup.1 and R.sup.2 can be selected from alkyl radicals of 1 to 8 
carbon atoms such as methyl, ehtyl, propyl, etc.; cycloalkyl radicals such 
as cyclohexyl, cycloheptyl, etc.; mononuclear radicals such as phenyl, 
methylphenyl, ethylphenyl, etc.; alkenyl radicals such as vinyl, allyl, 
etc.; and halogen substituted monovalent hydrocarbon radicals such as 
3,3,3,-trifluoropropyl. In addition, R.sup.1 and R.sup.2 can be selected 
from monovalent ketone radicals such as pent-4-onyl radicals, monovalent 
ester radicals such as acetoxy ethyl-radicals; and monovalent ether 
radicals such as methoxy ethyl-, methoxy ethoxyethyl, and so forth. 
Before proceeding to a definition of the other radicals in the compound of 
Formula (1), it is necessary to say something about the difference between 
the compounds of Formula (1) and the compounds of Formula (2). The 
compounds of Formula (1) are silane scavenging compounds. The compounds of 
Formula (2) are siloxane scavenging compounds. It is also necessary to 
point out that the scavenging leaving group in the compounds and silanes 
of Formula (1) is of a more limiting nature than the amino-scavenging 
leaving group of the compounds of Formula (2). 
Now proceeding to the definition of the other radicals, R.sup.5 and R.sup.6 
are all individually selected from hydrogen and C.sub.1-8 monovalent 
hydrocarbon radicals. The R.sup.3 group can be selected from the same 
groups as R.sup.5 and R.sup.6, and in addition, a radical of the formula, 
##STR6## 
where R.sup.8 and R.sup.9 are individually selected from the class 
consisting of hydrogen and C.sub.1-8 monovalent hydrocarbon radicals and 
R.sup.7 is defined as indicated below. Examples of the radicals, that the 
R.sup.8, R.sup.9, R.sup.5, R.sup.6 and R.sup.3 groups can be selected from 
are, for instance, hydrogen, and all C.sub.1-8 monovalent hydrocarbon 
radicals such as, alkyl radicals, for instance, methyl, ethyl, propyl, 
etc.; alkenyl of 2 to 8 carbon atoms such as vinyl, allyl, etc.; 
cycloalkyl radicals such as cyclohexyl, cycloheptyl, etc.; mononuclear 
radicals such as phenyl, phenylethyl, etc.; and halogen substituted 
monovalent hydrocarbon radicals of 1 to 8 carbon atoms, such as 
3,3,3-trifluoropropyl. In addition, any of those radicals can be selected 
from ether hydrocarbon radicals, such as methoxyethyl, etc. The R.sup.4 
and the R.sup.7 radicals are, on the other hand, selected from divalent 
hydrocarbon radicals of 2 to 8 carbon atoms and halogen substituted 
divalent hydrocarbon radicals of 2 to 8 carbon atoms including ether 
radicals; examples of such radicals are, for instance, alkylene radicals 
of 2 to 8 carbon atoms; cycloalkylene radicals of 2 to 8 carbon atoms; 
arylene radicals of 2 to 8 carbon atoms, such as for instance, phenylene; 
and divalent ether radicals of 2 to 8 carbon atoms such as, for instance, 
ethylene, oxyethylene, etc. 
In the compounds of Formula (2) the radicals R.sup.1, R.sup.2, R.sup.3, 
R.sup.5, R.sup.6, R.sup.4, R.sup.7, R.sup.8, R.sup.9 are defined in the 
same manner. That is, the radicals in the groups represented by A have the 
same definition as given above for these radicals in the compounds of 
Formula (1). As stated in the above compounds of Formula (2), the R.sup.1 
and R.sup.2 groups are defined the same as the same groups in the 
compounds of Formula (1). It should be noted that for the compounds of 
Formula (2), that the formula is an average unit formula and represents 
the different groups on an average SiO unit in the siloxane chain. Such 
compounds of Formula (2) may vary from disiloxanes to polysiloxanes of up 
to 20 silicone atoms. The basic difference between the compounds of 
Formula (1) and Formula (2) is that the compounds of Formula (2) are 
siloxanes, that is, they have a backbone or polymer chain of silicone and 
oxygen atoms and are polymers while the compounds of Formula (1) are 
monomers of silicon atoms and are referred to as silanes. Further, the 
amines of the A group in the compounds of Formula (2) are more broadly 
defined than the monomers of Formula (1); that is, the amine-functionality 
in the compounds of Formula (2) is broader and encompasses more types of 
amine functionality than the amine functionality of the compounds of 
Formula (1). The amine functionality of the A group in the compounds of 
Formula (2) encompasses an amine functionality where there is a single 
nitrogen atom as well as the case where there are 2 nitrogen atoms in the 
amine functionality similar to that of the silanes of the compounds of 
Formula (1). 
The compounds of Formula (2) can be used as integrated cross-linking agents 
within the scope of the instant case in the formations of the RTV 
compositions of the instant case. 
The reaction by-products formed from the compounds of Formula (2) may be 
gaseous, liquid, or solid, depending on the A group functionality; while 
the reaction by-products of the compounds of Formula (1) when they react 
with unbonded hydroxy groups in the composition may be liquids or solids. 
In this respect the scavenging and integrated cross-linking compounds of 
Formula (2) are more versatile than the scavenging and integrated 
cross-linker scavenging compounds of Formula (1). In the foregoing 
formulas given above and particularly, Formula (1), z is a whole number of 
0 to 1; a is a whole number that varies from 1 to 4; and the sum of a+z 
can vary from 1 to 4. Accordingly, in order for the compound of Formula 
(1) to be an integrated cross-linker, scavenger, it has to have at least 
one alkoxy group and preferably two such groups. If it has less than one 
or two alkoxy groups, it will be solely a scavenging compound. If it has 
one, two or more alkoxy groups, then it will be an integrated 
cross-linker, scavenger; that is, a compound that can end-cap a silanol 
end-stopped base polymer as was explained above to produce a base 
alkoxy-terminated diorganopolysiloxane compound. 
In the compounds of Formula (2), the values of x, y and w are given so that 
the compound is an integrated cross-linker, scavenger compound or pure 
scavenging compound. 
Further, with respect to the compounds of Formula (2) and (7) they have to 
have at least one alkoxy group in the polymers and preferably two, as well 
as preferably one A group. Further, while A groups as well as alkoxy 
groups can be tolerated in the polymer chain, they should not be present 
to too great an extent since too extensive cross-linking will take place. 
Although this is not as important in the case of disiloxanes and 
trisiloxanes, it becomes more important with the higher molecular weight 
siloxanes of the compounds of Formula (2). 
Accordingly, the compounds of Formula (1) and (2) for which the above 
definitions have been given, can be scavenging compounds, that is, pure 
scavenging compounds, or can be integrated cross-linker, scavenging 
compounds which can function as end-cappers or as pure scavenging 
compounds depending on the way they are used and the quantities that are 
used. As set forth in LUCAS, Ser. No. 449,105, the composition can 
function as an all alkoxy one-component RTV composition with the desired 
properties if it has up to 50% by weight of diorganopolysiloxane polymer 
in it terminated solely by one alkoxy group. The remaining base polymer 
has to be terminated by at least two alkoxy groups on each end of the 
polymer chain. Preferably the total base polymer is terminated by at least 
two alkoxy groups on the terminal silicon atom of the polymer chain. 
Further, preferably the diorganopolysiloxane polymers can be blends of 
diorganopolysiloxane polymers having a viscosity in the ranges indicated 
above, that is, of 100 to 1,000,000 centipoise at 25.degree. C. More will 
be said about the makeup of the base polymer other than the terminal 
groups when reference is made to the silanol terminated 
diorganopolysiloxane polymer from which it is formed as will be explained 
below. 
Proceeding now to the preparation of the composition; in addition to the 
alkoxy-terminated base polymer and the scavenging compound for absorbing 
or reacting with free hydroxy groups or unbonded hydroxy groups, the 
composition has to have a condensation catalyst in order for the 
composition to cure as an RTV composition. 
Effective amounts of the condensation catalysts which can be used in the 
practice of the present invention to facilitate the cure of the RTV 
compositions are, for example, 0.001 to 1 part based on the weight of 100 
parts of the silanol-terminated polydiorganosiloxane of Formula (8). These 
are included tin compounds, for example, dibutyltindilaurate; 
dibutyltindiacetate; dibutyltindimethoxide; carbomethoxyphenyl tin 
tris-uberate; tin octoate; isobutyl tin triceroate; dimethyl tin 
dibutyrate; dimethyl tin dineodeconoate; triethyl tin tartrate; dibutyl 
tin dibenzoate; tin oleate; tin naphthenate; butyltintri-2-ethylhexoate; 
tinbutyrate. The preferred condensation catalysts are tin compounds; and 
dibutyltindiacetate is particularly preferred. 
Titanium compounds which can be used are, for example, 
1,3-propanedioxytitanium bis(ethylacetoacetate); 1,3-propanedioxytitanium 
bis(acetylacetonate); diisopropoxytitanium bis(acetylacetonate); titanium 
naphthenate; tetrabutyltitanate; tetra-2-ethylhexyltitanate; 
tetraphenyltitanate; tetraoctadecyltitanate; ethyltriethanolaminetitanate. 
In addition beta-dicarbonyltitanium compounds as shown by WEYENBERG, U.S. 
Pat. No. 3,334,067 can be used as condensation catalysts in the present 
invention. 
Zirconium compounds, for example, zirconium octoate, also can be used. 
Further examples of metal condensation catalysts are, for example, lead 
2-ethyloctoate; iron 2-ethylhexoate; cobalt 2-ethylhexoate; manganese 
2-ethylhexoate; zinc 2-ethylhexoate; antimony octoate; bismuth 
naphthenate; zinc naphthenate; zinc stearate;. 
Examples of nonmetal condensation catalysts are hexylammonium acetate and 
benzyltrimethylammonium acetate. 
Various fillers and pigments can be incorporated in the silanol or 
alkoxy-terminated organopolysiloxane, such as for example, titanium 
dioxide, zirconium silicate, silica aerogel, iron oxide, diatomaceous 
earth, fumed silica, carbon black, precipitated silica. glass fibers, 
polyvinyl chloride, ground quartz, calcium carbonate etc. The amounts of 
filler used can obviously be varied within wide limits in accordance with 
the intended use. For example, in some sealant applications, the curable 
compositions of the present invention can be used free of filler. In other 
applications, such as the employment of the curable compositions for 
making binding material on a weight basis, as much as 700 parts or more of 
filler, per 100 parts of organopolysiloxane can be employed. In such 
applications, the filler can consist of a major amount of extending 
materials, such as ground quartz, polyvinylchloride, or mixtures thereof, 
preferably having an average particle size in the range of from about 1 to 
10 microns. 
The compositions of the present invention also can be employed as 
construction sealants and caulking compounds. The exact amount of filler, 
therefore, will depend upon such factors as the application for which the 
organopolysiloxane composition is intended, the type of filler utilized 
(that is, the density of the filler and its particle size). Preferably, a 
proportion of about 10 to 300 parts of filler which can include up to 
about 35 parts of a reinforcing filler, such as fumed silica filler, per 
100 parts of silanol-terminated organopolysiloxane is utilized. 
In addition to the filler, other various ingredients can be added to the 
composition, such as adhesion promoters, plasticizers of one type or 
another, heat age additives and sag control additives as disclosed in the 
patent application of BEERS, Ser. No. 349,537, and as disclosed in LUCAS, 
Ser. No. 349,538. All the patents and patent applications in the present 
case are incorporated by reference. In addition, the point that has been 
made above is that a metal condensation catalyst has to be present in the 
composition in order for the alkoxy-terminated diorganopolysiloxane 
polymer to cure in a manner that is well-known or identified with a 
silicone elastomer. If a metal condensation catalyst is not present, then 
the composition will cure very slowly, and will most probably have the 
consistency of a cheesy mass. In addition to the condensation catalyst, 
there may be further present in the composition an affective amount of 
cross-linking silane of the formula, 
##STR7## 
where R.sup.1 and R.sup.2 are individually selected from C.sub.1-13 
monovalent hydrocarbon radicals as identified previously and b is a whole 
number equal to 0 or 1. 
A mechanistic study of the RTV of the present invention supports the theory 
that the use of the scavenging silane of Formula (1) or (2) below or in 
combinations thereof with the cross-linking silane of Formula (3), in 
accordance with the practice of the invention, minimize the likelihood 
that detrimental amounts of R.sup.1 OH will be generated during the shelf 
storage period. Preferably there is utilized from 0.5 to 10 parts by 
weight of the excess cross-linking agent silane of Formula (3) per 100 
parts by weight of the base alkoxy-terminated diorganopolysiloxane 
polymer. 
In addition to the cross-linking silane there is preferably present an 
effective amount of a cure accelerator selected from a group consisting of 
substituted guanidines, amines and mixtures thereof. Among the curing 
accelerators which can be used in the practice of the invention are silyl 
substituted guanidines having the formula, 
EQU (Z).sub.g Si(OR.sup.1).sub.4-g, (4) 
where R.sup.1 is as previously defined, Z is a guanidine radical of the 
formula, 
##STR8## 
R.sup.22 is divalent C.sub.2-8 alkylene radical, R.sup.20 and R.sup.21 are 
selected from hydrogen and C.sub.1-8 alkyl radicals and g is an integer 
equal to 1 to 3 inclusive. In addition, alkyl substituted guanidines 
having the formula, 
##STR9## 
where R.sup.20 and R.sup.21 are as previously defined and R.sup.24 is a 
C.sub.1-8 alkyl radical, also can be employed. Some of the silyl 
substituted guanidines included with Formula (4) are shown by Takago, U.S. 
Pat. Nos. 4,180,642 and 4,248,993. 
Preferably there is utilized from 0.1 to 10 parts of the cure accelerator 
per 100 parts of the base alkoxy-terminated diorganopolysiloxane polymer. 
For more information as to such cure accelerators in compositions of the 
instant case, one is referred to the disclosure of WHITE, et al, U.S. Pat. 
No. 4,395,526. 
In addition to the foregoing base alkoxy-terminated diorganopolysiloxane 
polymer and the scavenging compounds of Formula (1) and (2) there may be 
present a polyalkoxy-terminated diorganopolysiloxane polymer of the 
formula, 
##STR10## 
where R, R.sup.1 and R.sup.2 are individually selected from C.sub.1-13 
monovalent hydrocarbon radicals as defined previously, e is a whole number 
which is equal to 0 or 1, inclusive, b is a whole number which is equal to 
0 or 1, inclusive, and the sum of b+e is equal to 0 or 1, inclusive, n is 
an integer having a value of from 50 to 2500 inclusive, and X is a 
hydrolyzable leaving group selected from the group consisting of amido, 
cyclic amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, 
thioisocyanato and ureido radicals. Further, X can be the same as A in 
Formula (2). 
It should be noted that the cure accelerator is preferably selected from 
di-n-hexylamine and di-n-butylamine, and that the condensation catalyst is 
preferably selected from dibutyltindiacetate and dibutyltindilaurate. 
The compound of Formula (5) is a polymer that is produced by reacting a 
silanol-terminated diorganopolysiloxane polymer with generally the 
integrated cross-linker, scavenging compounds of WHITE, et al, U.S. Pat. 
NO. 4,395,526, or more preferably, by reacting the silanol-terminated 
diorganopolysiloxane polymer with an integrated cross-linker, scavenging 
compound of Formula (1) or Formula (2) in which the integrated 
cross-linker, scavenger has at least two alkoxy groups on the terminal 
silicone atoms. Although the compounds of Formula (5) need not be present 
in the composition, they may be present in varying quantities and will not 
detract from the end properties of the desired composition. It is 
disclosed in the compounds of Formula (5) that X can be all of the 
foregoing hydrolyzable leaving groups since that does not detract from the 
properties of the composition. Preferably, X is an amino-functional 
hydrolyzable leaving group in accordance with the instant invention or an 
amino hydrolyzable leaving group in accordance with the invention of 
WHITE, et al, U.S. Pat. No. 4,395,526. 
In the preferred embodiment of the instant invention, it is preferred that 
R, R.sup.1 and R.sup.2 be methyl; R.sup.6 and R.sup.3 be hydrogen; and 
R.sup.5 be methyl. It is also preferred that the tin condensation catalyst 
be selected from dibutyltindiacetate and dibutyltindilaurate. In the 
instant invention a cure accelerator is not strictly necessary because the 
amine functionality of the scavenger compound acts as an accelerator. The 
compounds of Formula (1) and (2) are both scavenging compounds and within 
the scope of the formulas can be both pure scavenging compounds and 
integrated crosslinker, scavenging compounds. In a more preferred 
embodiment of the instant invention there is disclosed a shelf-stable, 
fast-curing one-component RTV composition comprising a silanol-terminated 
diorganopolysiloxane polymer having a viscosity in the range of 100 to 
1,000,000 centipoise at 25.degree. C. where the organo group is a 
monovalent hydrocarbon radical and preferably a C.sub.1-13 monovalent 
hydrocarbon radical and an integrated cross-linker, scavenger selected 
from (i) silanes of the formula, 
##STR11## 
and (ii) a preferred integrated cross-linker, siloxane compound of the 
formula, 
##STR12## 
where R.sup.1 and R.sup.2 are individually selected from C.sub.1-13 
monovalent hydrocarbon radicals; R.sup.5 and R.sup.6 are individually 
selected from the class consisting of hydrogen and C.sub.1-8 monovalent 
hydrocarbon radicals; R.sup.4 is a C.sub.2-8 divalent hydrocarbon radical; 
and R.sup.3 is selected from the class consisting of hydrogen, C.sub.1-8 
monovalent hydrocarbon radicals and a radical of the formula, 
##STR13## 
wherein R.sup.8 and R.sup.9 are independently selected from the class 
consisting of hydrogen and C.sub.1-8 monovalent hydrocarbon radicals and 
R.sup.7 is a C.sub.2-8 divalent hydrocarbon radical. In the above Formulas 
(6) and (7), R.sup.1, R.sup.2, R.sup.5, R.sup.6, R.sup.4, R.sup.3, 
R.sup.7, R.sup.8, and R.sup.9 all have the same definitions as given 
previously for the compounds of Formula (1) and (2). The only difference 
from the compounds of Formula (1) is that z is a whole number equal to 0 
or 1; q is a whole number equal to 1, 2 or 3; and the sum of q+z can vary 
from 1 to 3. That is, in the compounds of Formula (6) there must always be 
one alkoxy group and preferably two or more alkoxy groups if the compound 
is to function as an integrated cross-linker, scavenger. With respect to 
the compounds of Formula (7), R.sup.1, R.sup.2 and A have the same 
definitions as given previously for the compounds of Formula (2). The only 
difference in the definition of the compounds of Formula (7) is that m 
varies from 0.15 to 2.50; n varies in the range from 0.1 to 1.9; and o 
varies in the range from 0.05 to 2.00 and the sum of m, n and o varies in 
the range of 2.10 to 3.00. In the compounds of Formulas (2) and (7) there 
must be present at least one alkoxy group on the silicon atoms in the 
polymer and preferably one alkoxy group on the terminal silicon atoms. 
Further, in an all alkoxy system, the base polymers do not have any 
hydrolyzable leaving group other than alkoxy; for such systems there can 
be present a polymer species in which 50% by weight of the polymer species 
are polymers with only a single alkoxy-group on the terminal silicon atom, 
and the other 50% of the polymer species are diorganopolysiloxane base 
polymers with at least two alkoxy groups on the terminal silicon atom. 
However, for polymer systems having polymers such as that of Formula (5) 
where there is at least one hydrolyzable leaving group such as an amine 
functional group on the terminal silicon atoms and there is one or more 
alkoxy groups on the terminal silicon atoms, then the total base polymer 
system can be made up of such a polymer. There does not have to be mixed 
in such a base polymer system another base polymer having at least two 
alkoxy groups in the terminal silicon atom of the polymer chain. 
Further, there will not be attempted to be shown all the polymers that can 
arise from the situation when the integrated cross-linker, scavenger is a 
compound of Formula (7). It can be envisioned that various branch chains 
can be formed on the terminal silicon atom when the integrated 
cross-linker is a compound of Formula (7). Only the formulas of the 
preferred polymer systems formed from the compounds of integrated 
cross-linker, scavengers of Formula (6) and (7) will be shown below. 
Again, in such a composition, along with the silanol polymer and 
integrated cross-linker, scavenger there has to be present a condensation 
catalyst or the composition will not cure to a silicone elastomer or to 
the consistency and physical properties associated with silicone 
elastomers. 
The silanol-terminated diorganopolysiloxane polymer preferably has the 
formula, 
##STR14## 
where R is individually selected from C.sub.1-13 monovalent hydrocarbon 
radicals and n is a whole number that varies from 50 to 2500 and more 
preferably varies from 500 to 2000. Preferably the polymer has a viscosity 
that varies from 100 to 1,000,000 centipoise at 25.degree. C. and more 
preferably varies from 1,000 to 250,000 centipoise at 25.degree. C. The 
definition of the R radical in Formula (8) is the same as given for the 
group R in Formula (5) and (9) and can be the same as given previously for 
R.sup.1 and R.sup.2 in the foregoing definitions. Preferably, R is 
individually selected from methyl or a mixture of a major amount of methyl 
and a minor amount of phenyl, cyanoethyl, trifluoropropyl, vinyl and 
mixtures thereof. The silanol-terminated polymer of Formula (8) may have 
silanol groups in the polymer chain which can be converted to alkoxy 
groups or siloxy groups having hydrolyzable leaving groups thereon when 
the silanol diorganopolysiloxane polymer of Formula (8) is reacted with 
the integrated cross-linker, scavenger of Formulas (6) and (7). Too many 
of such groups are undesirable, since they cause undue cross-linking and 
undesirable properties in the final products. Preferably, the 
silanol-terminated diorganopolysiloxane polymer of Formula (8) has as few 
silanol groups in the polymer chain as possible so that there will not be 
undue cross-linking in the polymer chain. Further, the silanol-terminated 
diorganopolysiloxane can be a polymer specie of a single viscosity or it 
can be a blend of various polymer species of different viscosities. It is 
only necessary that the blend of viscosity of the polymer have a viscosity 
in the ranges indicated above. Utilizing the integrated cross-linker, 
scavengers of Formulas (6) and (7) which are reacted with a 
silanol-terminated polymer of Formula (8) there can be produced an 
alkoxy-terminated polymer that has the formula, 
##STR15## 
where R, R.sup.1, R.sup.2, R.sup.5, R.sup.6, R.sup.4, R.sup.7, R.sup.8, 
R.sup.9 are as defined previously; s is a whole number that is 0 or 1; t 
is a whole number that is is equal to 1 or 2 and the sum of s+t is equal 
to 1 to 2 and A is defined as given for Formulas (2) and (7). The 
compounds of Formula (9) are the preferred polymers that are formed by the 
reaction of the compounds of Formula (8) and the integrated cross-linker, 
scavengers of Formulas (6) and (7). No end-coupling catalyst is needed for 
such a reaction since the amine groups in the integrated cross-linker, 
scavengers of Formulas (6) and (7) function as catalysts to rapidly 
end-cap the silanol-terminated diorganopolysiloxane polymer of Formula 
(8). 
Again there may be utilized excess amounts of cross-linking silane of 
Formula (3) in the same amounts as given previously with such a polymer as 
well as the same condensation catalysts as mentioned previously. Also, 
there may be used the same cure accelerators discussed previously with the 
previous embodiment. There may also be present the same additives, same 
fillers, adhesion promoters and other additives in the same quantities as 
discussed previously and as disclosed in WHITE, et al, U.S. Pat. No. 
4,395,526. As noted previously, the compounds of Formula (9) are the 
preferred compounds that are formed or alkoxy-terminated polymers that are 
formed when the integrated cross-linker, scavengers of Formula (6) and (7) 
are reacted with a silanol-terminated diorganopolysiloxane polymer. There 
will not be attempted to be shown in this application all the different 
and various types of polymers, that is, alkoxy-terminated polymers, that 
can be prepared or formed by the reaction of such compounds. 
The compounds or polymer species of Formula (9) are the polymer species 
that are present in major amounts when the integrated scavengers, 
cross-linkers of Formula (6) and (7) are are reacted with a 
silanol-terminated diorganopolysiloxane polymer of Formula (8). In the 
reaction mixture, all polymer species will not be of Formula (9). There 
will be some polymer species which will cross-link with each other and 
have slightly different configurations than that of FIG. (9). However, the 
majority of the polymer species in the polymer mixture if prepared in a 
substantially anhydrous manner will be the alkoxy-terminated polymers of 
Formula (9). These polymer species whether having just one alkoxy-group on 
the terminal silicon atoms or having more than one alkoxy group on the 
terminal silicon atoms can be utilized as 100% of such in the base polymer 
material. 
With the polymer of Formula (9) there may be mixed in any proportions the 
polymers of Formula (5) as well as any of the other ingredients necessary 
or desirable or common with such alkoxy-functional one-component RTV 
compositions as disclosed in the foregoing patents and patent 
applications. The polyalkoxyterminated polymers of Formula (5) can be 
mixed in any proportions with the polymers of Formula (9) irrespective of 
whether the polymers of Formula (9) have just one or more alkoxy groups in 
the terminal silicon atom, since both will cure to a silicone elastomer 
with the traditional properties of silicone elastomer along with a 
condensation catalyst. Examples of these scavenging silanes and siloxanes 
of Formulas (1) and (2) are as follows: 
##STR16## 
In the formulas above and below, Me is methyl, Et is ethyl and .phi. is 
phenyl. Examples of integrated cross-linker, scavenging comounds which 
come within the scope of compounds of Formulas (6) and (7) and, of course, 
(1) and (2) are as follows: 
##STR17## 
The composition is prepared by simply first producing the end-capped 
polymer either by reacting the polyalkoxy, cross-linking agent with a 
silanol-terminated diorganopolysiloxane polymer of Formula (8) with an 
end-capping catalyst, and then adding to it the scavenging compound and 
the other ingredients as necessary. Where an integrated cross-linker, 
scavenger compound of the instant case is utilized, then the integrated 
cross-linker, scavenger compound is added to the silanol-terminated 
polymer without a catalyst so as to produce the end-capped polymer. Then 
the other ingredients are added as desired. This can be done continuously 
or semicontinuously in a devolatilizing extruder as disclosed in CHUNG, 
Ser. No. 437,895. It must be, of course, obvious that the foregoing mixing 
is carried out in an anhydrous manner and that the RTV composition is 
prepared and stored in a substantially anhydrous manner if it is desired 
to preserve the curing properties of the composition. When it is desired 
to cure the composition, it is exposed to atmospheric moisture whereupon 
it will fully cure to a silicone elastomer with full cure taking place in 
24 hours. In any case, it is necessary to form the alkoxy-terminated 
polymer first before the other ingredients are added, and preferably 
adding the scavenging compound to the composition before the other 
ingredients. When an integrated cross-linker, scavenging compound is 
utilized, such as that of Formula (2), (6) and (7) then it is not 
necessary to add an end-coupling catalyst since these amine functional 
compounds function themselves as catalysts. The reaction is 
auto-catalytic. With respect to the amount of scavenging silane that is 
utilized when an integrated cross-linker, scavenger compound is utilized, 
it is, of course, necessary that there be utilized excess scavenging 
compound or integrated cross-linker, scavenging compound to bond with the 
unbonded hydroxy groups in the composition. Generally from 0.5 to 10 parts 
by weight of the scavenging compound is utilized when it is utilized as a 
scavenger for unbonded hydroxy groups in the composition per 100 parts of 
the base alkoxy-terminated diorganopolysiloxane polymer or per 100 parts 
of the base silanol-terminated diorganopolysiloxane polymer base polymer. 
The composition is substantially acid free. 
The expression "substantially acid-free" with respect to defining the 
elastomer made from the RTV composition of the present invention upon 
exposure to atmospheric moisture means yielding byproducts having a pKa of 
5.5 or greater with 6 or greater preferred and 10 or greater being 
particularly preferred. 
Minor amounts of amines, substituted guanidines, or mixtures thereof, can 
be utilized as curing accelerators in the polyalkoxy compositions of the 
present invention. There can be used from 0.1 to 5 parts, and preferably 
about 0.3 to 1 part of curing accelerator, per 100 parts of the 
silanol-terminated polymer of Formula (9) to substantially reduce the 
tack-free time (TFT) of the RTV composition of the present invention. This 
enhanced cure rate is maintained after it has been aged for an extended 
shelf period, for example 6 months or more at ambient temperatures, or a 
comparable period under accelerated aging conditions. Its cure properties 
after the extended shelf period will be substantially similar to its 
initial cure properties, for example, tack-free time (TFT), shown by the 
RTV composition upon being freshly mixed and immediately exposed to 
atmospheric moisture. 
With respect to the silane scavenger of Formulas (1), (2), (6), and (7) in 
determining what levels to use in the practice of the instant invention, 
the total hydroxy-functionality of RTV compositions can be estimated. The 
total hydroxy functionality of the polymer can be determined by infrared 
analysis. In order to insure that an effective or stabilizing amount of 
scavenger is used to maintain the stability of the composition over an 
extended shelf period of six months or more at ambient temperature while 
in a sealed container, there can be used an additional amount of scavenger 
over that amount required to endstop the polymer. This excess of scavenger 
can be up to about 3% by weight, based on the weight of the polymer. The 
aforementioned 3% of savenger by weight exceeds that amount required to 
substantially eliminate available hydroxy functionality in the polymer as 
a result of reaction between OH functionality and X radicals. In 
compositions which also contain filler and other additives, the additional 
amount of scavenger of Formulas (1), (2) or (6), (7) which is required is 
estimated by running a 48-hour stability check at 100.degree. C. to 
determine whether the tack-free time remains substantially unchanged as 
compared to the tack-free time of the composition before aging, measured 
under substantially the same conditions. The latter procedure is a more 
imperical method of determining the amount of scavenger necessary to 
scavenge the unbonded hydroxy groups in the manufacture of a particular 
composition and is given above as a guide in the manufacture of such 
compositions. The foregoing compounds of Formula (1), (2), (6) and (7) can 
be produced by methods known in the art. Thus, in such a procedure the 
appropriate chlorosilane is taken and dissolved in any of the inert 
organic solvents such as, for instance, hydrocarbon solvents such as 
cyclohexane, cycloheptane, etc.; and aromatic solvents such as xylene, 
toluene, etc. To this solution there is added the appropriate amine and 
the composition is heated at anywhere from room temperature to the reflux 
temperature of the solvent which can be up to 110.degree. to 120.degree. 
C. or more. A necessary aspect of the invention is there should be used a 
slight excess of the amine over the amount of the chlorosilane or 
siloxane. Thus, preferably there is utilized from 5 to 20% excess of the 
amine over the stoichiometric amount needed to react with the chlorosilane 
or siloxane. Stoichiometrically there is needed two moles of the amine per 
mole of chlorine to be replaced in the chlorosilane or siloxane. Twice the 
amount of amine is needed so that the amine halogen salt can be formed and 
precipitate out of solution, so that it can be removed. Further, by using 
a slight excess of 5 to 20% of amine as indicated above under preferred 
conditions, it is possible to obtain the maximum yield of desired product 
and minimize the formation of by-products. Such a reaction usually takes 
place in the foregoing temperature range in a period of time varying 
anywhere from 1/2 hour to 5 hours or more, preferably taking place in a 
period of time occuring from 1/2 hour to 2 hours. Preferably, the reaction 
takes place under pressure; especially when the amine is a gas, thus 
increasing the rate of reaction. The pressure that can be utilized can be 
anywhere from 1 to 10 pounds above absolute. Excessive pressure is not 
necessary. After the reaction has proceeded to completion, the amine 
halogen salt that is formed is filtered out and the solvent is stripped 
off to give the desired product. The desired product is kept in an 
anhydrous manner since it will hydrolyze very easily with moisture. The 
resulting product of Formulas (1), (2) or coming within the scope of (6) 
and (7) can then be utilized to prepare the compositions of the instant 
case. 
The examples below are given for the purpose of illistrating the present 
invention. They are not given for any purpose for setting limits and 
boundaries to the instant invention.

EXAMPLE I 
Synthesis of Methyldimethoxychlorosilane, 3 
To a 3,000 ml, round bottom, three-necked flask was attached a mechanical 
stirrer, a thermometer, a dropping funnel equipped for adding methanol 
below the surface of the liquid, and a reflux condenser. To the flask was 
added 1423 parts (9.5 moles) of methyltrichlorosilane while to the 
dropping funnel was added 609 parts (19.0 moles) of anhydrous methanol. 
While stirring, the methanol was added at a rate of 1.7 ml/min and samples 
were withdrawn periodically for analysis by gas chromatography. At the end 
of methanol addition, the reaction mixture was heated to 50.degree. C. and 
then cooled and bottled. During the addition of methanol, the reaction 
temperature was maintained between 21.degree.-29.degree. C. The final 
product yield was 1132.5 parts (88.3%). Analysis by titration for % Cl was 
21.5 (Theory=25.3). 
Synthesis of Methyldimethoxy-N-methylaminosilane, 2 
To a 3,000 mL, flask equipped with a mechanical stirrer, a thermometer, a 
dropping funnel, a reflux condenser and a tube dipping below the liquid 
layer for feeding in methylamine, was added 1500 parts of hexane to which 
methylamine was bubbled through at a rapid rate. A sample of the hexane 
when analyzed by gas chromatography showed less than 500 ppm methylamine 
after bubbling in the gas for 30 minutes. Titration for % amine revealed 
0.82% amine in the hexane solution. To the dropping funnel was added 572 
parts (4.07)moles) of methyldimethoxychlorosilane which was added to the 
hexane while bubbling in methylamine. The rate of addition of methylamine 
was controlled so that its concentration was always in excess of the 
chlorosilane in the solution. This was monitored by detecting excess 
methylamine at the condenser exit. At the end of the addition of the 
chlorosilane, the liquid was separated from the solid by filtration and 
the solid was washed with fresh hexane. The filtrate obtained was 
distilled through a 75 cm, glass helices packed column with a 2:1 reflux 
ratio. A total of 1625 parts of hexane was recovered from the 
distillation. The residue remaining was collected and weighed. The yield 
of product was 467 parts (85%). Analysis by gas chromatography showed 79% 
methyldimethoxy-N-methylaminosilane, 15% methyltrimethoxysilane and no 
detectable dimer. Titration of the product for amine content showed 18.6% 
MeNH (Theory=22.1%). 
A sample of crude methyldimethoxy-N-methylaminosilane was distilled to get 
pure material (b.p. 122.degree.-123.degree. C.) so that the pure 
endcapping/crosslinking agent could be effectively compared with the crude 
material. Both of these materials were reacted with silanol-stopped 
polydimethylsiloxane. 
Additionally, the bis compound was isolated as a mixture. It was 68% pure. 
EXAMPLE II 
Evaluation of Endcapping/Cross-linking Reaction of Pure, Distilled 
Methyldimethoxy-N-Methylaminosilane with Silanol Polymer 
Into a 1000 mL polymer flask was weighed 1000 parts of a silanol-endstopped 
polydimethylsiloxane (0.1274% Si-OH) which had a viscosity of 2,550 
centipoises at 25.degree. C. To this was added 40.5 parts of 
methyldimethoxy-N-methylaminosilane (92% pure) rapidly while stirring. 
Samples were withdrawn periodically from the reaction mixture and analyzed 
by titration for % amine and by near infrared spectroscopy for % silanol. 
Table I shows the results of these analyses and the data show the 
endcapping reaction to be very fast. 
TABLE I 
______________________________________ 
Analysis of In-Process Samples from Endcapping Reaction 
Sample No. 
Reaction Time 
% RNH.sub.2 
ppm Si--OH 
______________________________________ 
1 0 -- 1274 
2 7 min. 0.91 143 
3 1 hour 0.88 80 
4 2.5 hours 0.68 -- 
5 17 hours 0.14 -- 
6 20 hours 0.11 22.4 
______________________________________ 
The final product had a viscosity of 2,240 centipoises. When a sample of 
the endcapped polymer was mixed with dibutyltindilaurate and exposed to 
atmospheric moisture, it cured to an elastomer upon setting overnight. 
Material mixed with the tin catalyst and kept in a closed container away 
from moisture did not cure. Thus, the amine functions as a cure 
accelerator and no curing takes place in the absence of moisture. 
EXAMPLE III 
Evaluation of Endcapping/Cross-linking Reaction of Crude, Undistilled 
Methyldimethoxy-N-Methylaminosilane with Silanol Polymer 
To a polymer reaction flask was added 1000 parts of a silanol-stopped, 
polydimethylsiloxane containing 0.1274% silanol which had a viscosity of 
2,550 centipoises. To this was added 36.1 parts (0.27 mole) of 
methyldimethoxy-N-methylaminosilane. An initial sample was taken after 
stirring at room temperature for one hour. It showed 0.67% amine as 
CH.sub.3 NH.sub.2 and 33 ppm silanol. The reaction mixture was further 
treated in order to reduce the amine content. It was heated at 70.degree. 
C. and 60 mm for 30 min. (% CH.sub.3 NH.sub.2 =0.44), followed by purging 
overnight at room temperature with nitrogen (% CH.sub.3 NH.sub.2 =0.073) 
and then heated at 75.degree. C./25 mm for 2 hours (% CH.sub.3 NH.sub.2 
=0.046). The endcapped polymer had virtually no amine odor. 
EXAMPLE IV 
Evaluation of Endcapping/Cross-linking Reaction of 
1,3-Di-Methyl-1,1,3,3-Tetramethoxy-N-Methyldisilazane, 5, with Silanol 
Polymer 
To a 1000 mL polymer reaction flask was added 1000 parts of a 
silanol-stopped polydimethylsiloxane (0.1274% silanol) and 35.8 parts of a 
68:3 mixture of the silazane and methyldimethoxy-N-methylaminosilane. The 
reaction misture was stirred and then sampled after one hour. Analysis for 
% silanol by near infrared spectroscopy and % amine by titration showed 
values of 852 ppm and 0.51% respectively. These results show the silazane 
derivative, to be significantly slower reacting with silanol than the 
aminosilane. The reaction mixture was purged overnight with nitrogen 
whereupon it showed 407 ppm silanol and 0.44% amine. Upon continued 
purging, a sample after 48 hours showed 285 ppm silanol and 0.42% amine. 
The final viscosity was 2.280 centipoises. The yield was 1,002 parts. 
A portion of this material was mixed with dibutyltindilaurate and placed in 
a bottle free of contact with atmospheric moisture. When a part of this 
mixture was exposed to atmospheric moisture, it cured overnight to an 
elastomer. However, the material in the bottle increased in viscosity 
which indicated that coupling was occurring because of the presence of 
unreacted silanol due to the incomplete endcapping reaction. 
EXAMPLE V 
Synthesis of 1,3 bis(N-methylamino)-1,1,3,3-tetramethyldisiloxane 
This is a fictitious example. 
To a 3,000 mL flask there is added 1,500 parts of hexane through which 
methylamine is bubbled at a rapid rate. From a dropping funnel is added 
406 parts (2.0 moles) of 1,3 dichloro-1,1,3,3 tetramethyldisiloxane. The 
rate of addition of methylamine is controlled so that its concentration is 
always in excess of the chlorosilane in the solution. At the end of the 
addition, the solids are separated by filtration and distillation of the 
liquid phase gives 350 parts of a liquid identified as 
1,3-bis(N-methylamino)-1,1,3,3-tetramethyl-disiloxane. 
Evaluation of 1,3-bis(N-methylamino)-1,1,3,3-tetramethyldisiloxane as a 
scavenging compound for RTV compositions. 
When a mixture of a dimethoxy endstopped polydimethylsiloxane is mixed with 
the above mentioned compound, methyltrimethoxysilane and a tin soap, 
curing of the material to an elastomer occurred when exposed to 
atmospheric moisture. When moisture was excluded, no curing occurred even 
when stored at 100.degree. C. for 48 hours. After storage for 48 hours at 
100.degree. C. the material is then exposed to atmospheric moisture 
whereupon it cures to an elastomer. When the same composition is mixed 
except that the title scavenging compound is replaced by d-n-hexylamine, 
curing of the compound to an elastomer occurs. However, after storage of 
the same composition at 100.degree. C. for 48 hours, the material did not 
cure upon exposure to atmospheric moisture. Thus, this demonstrates the 
effectiveness of 1,3 bis(N-methylamino) 1,1,3,3 tetramethyldisiloxane to 
function as a scavenging compound. 
EXAMPLE VI 
Synthesis of methyldimethoxy-N,N-diethylaminosilane 
This is a fictitious example. 
To a 3,000 mL flask is added 1,500 parts of hexane to which 161 parts of 
diethylamine is added (2.2 moles). To this solution is added dropwise 240 
parts (2.0 moles) of methyldimethoxychlorosilane. At the end of the 
addition, the reaction mixture is filtered and the filtrate is distilled 
to remove hexane. The residue obtained, 320 parts, is the desired 
compound, methyldimethoxy N,N-diethylaminosilane. The yield is 90%. 
Evaluation of methyldimethoxy N,N-diethylaminosilane as 
cross-linker/scavenging compound for RTV compositions 
To a silanol end-stopped polydimethylsiloxane is added an appropriate 
amount of the above compound to react with all of the silanol and replace 
the end of the polymer chain with methyldimethoxysilyl groups. A slight 
excess of the compound is used so that it can function as a scavenger in 
addition to being used to endcap the silanol polymer. The resulting 
mixture is mixed with the appropriate amount of methyltrimethoxysilane and 
a tin soap. A sample of this mixture cures to an elastomer when exposed to 
atmospheric moisture. When moisture is excluded the sample did not cure 
even when stored for 48 hours at 100.degree. C. After 48 hours at 
100.degree. C., the compound cured to an elastomer when exposed to 
atmospheric moisture. This demonstrates the effectiveness of 
methyldimethoxy N,N-diethylaminosilane to function as a 
cross-linker/scavenger in RTV systems.