SUBSTANCES A BASE DE SILICONE RTV RESISTANT AUX MOISISSURES

MILDEW RESISTANT RTV SILICONE COMPOSITIONS

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
A mildew-resistant one component room temperature
vulcanizable silicone composition comprising a silanol
end-stopped diorganopolysiloxane polymer with a cross-
linking agent, a curing catalyst, and an effective amount
of a fungicide of the formula
<IMG>
where R is selected from the class consisting of hydrogen,
halogen, and alkyl radicals of 1 to 4 carbon atoms, and
R1 is selected from the class consisting of hydrogen,
iodine, and alkyl radicals of 1 to 4 carbon atoms. Such
compositions are useful as molds, as potting compounds, as
encapsulants and as sealants.

Revendications

- 26 - 60SI-348
The embodiments of the invention in which an
exclusive property or privilege is claimed are defined
as follows:
1. A mildew-resistant one-component room
temperature vulcanizable silicone composition comprising:
(A) 100 parts by weight of a silanol end-stopped diorgano-
polysiloxane of a viscosity varying from 100 to 500,000
centipoise at 25°C where the organo group is a monovalent
hydrocarbon radical; (B) from 0.01 to 15 parts by weight
of a cross-linking agent; (C) from 0.01 to 10 parts by
weight of a curing catalyst; and (D) an effective amount
of a fungicide of the formula
<IMG>
where R is selected from the class consisting of hydrogen,
halogen, and alkyl radicals of 1 to 4 carbon atoms, and
R1 is selected from the class consisting of hydrogen,
iodine, and alkyl radicals of 1 to 4 carbon atoms.
2. The composition of claim 1, wherein there are
present from 0.01 to 2 parts by weight of the fungicide.
3. The composition of claim 2, wherein the
fungicide has the formula
<IMG>
4. The composition of claim 2, wherein the
fungicide has the formula
<IMG>
5. The composition of claim 2, wherein the
fungicide is present in the composition as a dispersion
of the fungicide in butylated hydroxy toluene.
6. The composition of claim 2, wherein the

- 27 - 60SI-348
cross-linking agent has the formula
R2 Si (OCO R3)3
wherein R2 is an alkyl radical of 1 to 8 carbon atoms, and
R3 is an alkyl radical of 1 to 30 carbon atoms.
7. The composition of claim 6, wherein the
curing catalyst is a metal salt of a carboxylic acid with
the metal varying from lead to manganese in the Periodic
Table.
8. The composition of claim 7, wherein there
are present from 5 to 200 parts by weight of a filler.
9. The composition of claim 8, wherein the
cross-linking agent is methyltriacetoxy silane, and the
curing catalyst is a tin salt of a carboxylic acid.
10. The composition of claim 8, wherein the
cross-linking agent is methyl tris-(2-ethyl hexanoxy)silane .
11. The composition of claim 10, wherein the
curing catalyst is dibutyl tin oxide.
12. The composition of claim 10, wherein the
curing catalyst is dimethyl tin dineodecanoate.
13. The composition of claim 10, having further
from 2 to 20 parts by weight of a fluid polysiloxane
containing a high degree of trifunctionality, tetra-
functionality, or a mixture of tri- and tetrafunctionality
and comprising:
(i) from 25 to 60 mole percent of monoalkyl
siloxy units, siloxy units or a mixture of such units;
(ii) from 1 to 6 mole percent of trialkylsiloxy
units, and
(iii) from 37 to 74 mole percent of dialkylsiloxy
units, said polysiloxane containing from about 0.1 to 2
parts by weight of silicone-bonded hydroxyl groups.
14. The composition of claim 13, wherein there
are present from 0.03 to 2 parts by weight of a polyether
surfactant as a sag control additive.
15. The composition of claim 14, wherein there
are present from 5 to 30 parts by weight of silica filler
and from 5 to 170 parts by weight of calcium carbonate.

- 28 - 60S-I-348
16. The composition of claim 15, wherein there
are further present from 0.1 to 3 parts by weight of an
adhesion promoter selected from the class consisting of
silyl maleates, silyl fumarates and silyl succinates.
17. The composition of claim 2, wherein the
cross-linking agent is an alkyl trialkoxy silane, and
the curing catalyst is a titanium chelate.
18. The composition of claim 17, wherein there
are present from 5 to 20 parts by weight of silica filler
and from 5 to 180 parts by weight of an extending filler.
19. The composition of claim 18, wherein the
extending filler is calcium carbonate.
20. The composition of claim 18, wherein there
are further present from 1 to 50 parts by weight of a
plasticizer which is a triorgano silyl end-stopped
diorganopolysiloxane of a viscosity varying from 10 to
10,000 centipoise at 25°C and where the organo group is
a monovalent hydrocarbon radical.
21. The composition of claim 18, wherein there
are further present from 0.1 to 2 parts by weight of silyl
isocyanurate as an adhesion promoter.
22. A process for forming a mildew-resistant
one-component room temperature vulcanizable silicone com-
position comprising mixing: (A) 100 parts by weight of
a silanol end-stopped diorganopolysiloxane of a viscosity
varying from 100 to 500,000 centipoise at 25°C where the
organo group is a monovalent hydrocarbon radical; (B) from
0.01 to 15 parts by weight of a cross-linking agent;
(C) from 0.01 to 10 parts by weight of a curing catalyst;
and (D) an effective amount of a fungicide of the formula
<IMG>
where R is selected from the class consisting of hydrogen,
halogen, and alkyl radicals of 1 to 4 carbon atoms, and R1
is selected from the class consisting of hydrogen, iodine,
and alkyl radicals of 1 to 4 carbon atoms.

- 29 - 60SI-348
23. The process of claim 22, wherein there are
present from 0.01 to 2 parts by weight of the fungicide.
24. The process of claim 23, wherein the
fungicide has the formula
<IMG> .
25. The process of claim 23, wherein the
fungicide has the formula
<IMG> .
26. The process of claim 23, wherein the
fungicide is added to the mixture as a dispersion of the
fungicide in butylated hydroxy toluene.
27. The process of claim 23, wherein the cross-
linking agent has the formula
R2 Si (OCO R3)3
where R2 is an alkyl radical of 1 to 8 carbon atoms, and
R3 is an alkyl radical of 1 to 30 carbon atoms.
28. The process of claim 27, wherein the curing
catalyst is a metal salt of a carboxylic acid with the
metal ranging from lead to manganese in the Periodic Table.
29. The process of claim 28, wherein there are
present in the mixture from 5 to 200 parts by weight of a
filler.
30. The process of claim 29, wherein the
cross-linking agent is methyltriacetoxy silane, and the
curing catalyst is a tin salt of a carboxylic acid.
31. The process of claim 29, wherein the
cross-linking agent is methyl tris-(2-ethyl hexanoxy)silane .
32. The process of claim 31, wherein the curing
catalyst is dibutyl tin oxide.
33. The process of claim 31, wherein the curing
catalyst is dimethyl tin dineodecanoate.

- 30 - 60SI-348
34. The process of claim 31, further including
in the mixture from 2 to 20 parts by weight of a fluid
polysiloxane containing a high degree of trifunctionality,
tetrafunctionality, or a mixture of tri- and tetrafunction-
ality and comprising:
(i) from 25 to 60 mole percent of monoalkyl
siloxy units, siloxy units or a mixture of such units;
(ii) from 1 to 6 mole percent of trialkylsiloxy
units; and
(iii) from 37 to 74 mole percent of dialkylsiloxy
units, said polysiloxane containing from about 0.1 to 2
parts by weight of silicone-bonded hydroxyl groups.
35. The process of claim 34, wherein there are
present in the mixture from 0.03 to 2 parts by weight of a
polyether surfactant as a sag control additive.
36. The process of claim 35, wherein there are
present in the mixture from 5 to 30 parts by weight of silica
filler and from 5 to 170 parts by weight of calcium carbonate.
37. The process of claim 36, wherein there are
further present in the mixture from 0.1 to 3 parts by
weight of an adhesion promoter selected from the class
consisting of silyl maleates, silyl fumarates and silyl
succinates.
38. The process of claim 23, wherein there
cross-linking agent is an alkyl trialkoxy silane, and the
curing catalyst is a titanium chelate.
39. The process of claim 38, wherein there are
present in the mixture from 5 to 20 parts by weight of silica
filler and from 5 to 180 parts by weight of an extending
filler.
40. The process of claim 39, wherein the
extending filler is calcium carbonate.
41. The process of claim 39, wherein there are
further present in the mixture from 1 to 50 parts by
weight of a plasticizer which is a triorgano silyl end-
stopped diorganopolysiloxane of a viscosity varying from

- 31 - 60SI-348
10 to 10,000 centipoise at 25°C and where the organo group
is a monovalent hydrocarbon radical.
42. The process of claim 39; wherein there are
further present in the mixture from 0.1 to 2 parts by
weight of silyl isocyanurate as an adhesion promoter.

Description

7~1
- 1 Case 60SI-348
MILDEW RE~ISTANT RTV SILICONE COMPOSITIONS
Background Of The Invention
The present invention relates to room
temperature vulcani2able rubber compositions and
more particularly the present invention relates
to room temperature vulcanizable silicone rubber
compositions which are mildew resistant.
Room temperature vulcanizalbe silicone
rubber compositions are well known. One type of
room temperature vulcanizable silicone rubber
compositions comprises the reactio;n product of a
silanol end-stopper diorganopolysiloxane polymer
in combination with methyl triacetoxy silane
disclosed in Bruner, U.S. Patent No. 3,035,016 -
issued May 15, 1962, and Ceyzeriat, U~S. Patent No.
3,133,891 - issued May 19, 1964. Preferably these
compositions have a metal salt of a carboxylic acid
as a curing catalyst. The ingredients of the
composition are packaged in a substantially anhydrous
state and left as such. When it is desired to cure
~he composition, the package is broken and the
composition applied and in the presence of atmospheric
moisture the cross-linking agent hydroyizes to cross-
link and form a silicone elastomer; total cure taking
place in about 24 hours. Such compositions are
disclosed with various additives in them such as
adhesion promoters, flame retardant additives, oil

~ 17279:~
60SI-3~8
-- 2 --
resistant additives, heat aging additives, and
various other types of additives. These compositions
are known as one-component room temperature vulcanizable
compositions of the acetoxy type.
There is also another type of one component
room temperature vulcanizable silicone rubber
composition such as that disclosed in U.S. Patent No.
4,100,129 - M.D. Beers, which issued July 11, 1978.
This patent discloses a composition where the basic
ingredients are silanol end-stopped diorganopolysiloxane
polymer, a cross-linking agent which is methyltrimeth
methyltrimethoxysilane and a curing cataly~t which is
a titanium chelate. Such composition may also contain
plasticizers, adhesion promoters, flame retardant
additives, sag control additives and various types
of fillers as disclosed in the foregoing patent.
This composition is produced in the uncured state by
mixing the ingredients then packaging the composition
in a substantially anhydrous state. When it is desired
to cure the composition, the seal on the package
is broken, the composition is applied and when exposed
to atmospheric moisture, results in composition curing
to a silicone elastomer.
Such a composition may also be produced as
a two component system where the cross-linking agent
is kept separate from the silanol end-stopped
diorganopolysiloxane polymer where the catalyst is
a metal salt of a carboxylic acid and where the
cross-linking agent may either be methyl trimethoxysilane
or an orthosilicate such as tetraethylorthosilicate.
In the two component system, it is irrelevent
whether moisture is present in either of the two
packages and in some cases it is preferred that
moisture be present so as to increase the cure rate.
In such a two package system when it is desired to cure
.:

~ 172791L
- 3 - 60SI-348
the system, the two packages are mixed and the composition
applied which then cures to a silicone elastomer. As
can be appreciated, the one-component sys*em is preferred
over the two-component system, as the two-component
system requires additional application steps which
increase the cost of using it.
Recently there has been developed a new RTV
(short for room temperature vulcanizable) system such
as that disclosed in Beers Canadian Patent Application
10 Serial No. 330,424 filed June 22, 1979, entitled
"Curable Compositions and Processes". This RTV system
comprises a silanol end-stopped polymer, methyl
tris-(2-ethyl hexanoxy) silane as a cross-linking agent
and a metal salt of a carboxylic acid as the catalyst.
Such a composition has good oil resistance and high
temperature resistance, and is especially suited for
forming silicone gaskets. The composition may have
various additives, as disclosed in the foregoing Beers
patent application.
These different types of room temperature
vulcanizable silicone rubber composition have various
properties which can make one type suited for a particular
application over the others. The acetoxy system, while
inexpensive to make, may be undesirable because while
curing it releases acetic acid which is corrosive and
has a somewhat pungent odor. On the other hand,
the alkoxy systems are substantially noncorrosive
and do not have objectionable odors. There are
other one-component systems which utilize aminoxy
silanes as cross-linking agents, ketoxime silanes
as cross-linking agents, amide silanes as cross-
linking agents, and amine silanes as cross-linking
agents. However, these other room temperature
vulcanizable silicone rubber compositions which have
,,
. .

1 172791
60SI-348
~ 4
nitrogen functional silanes as cross-linking agents
have not found wide applicability at this point for
one reason or another. However, this is not to say
that such systems will not find wide applicability and
utilization in the future. The one-component systems
as well as the two component systems are well-known in
the field and are referred to as room-temperature
vulcanizable silicone rubber compositions or RTV
compositions testifying to the fact they cure or form
silicone elastomers upon standing at room temperature
and upon exposure to atmospheric moisture and have
- found wide applicability for various purposes.
They can be used to form molds, they are utilized as
potting compounds and as encapsulants. But more
particularly they have found wide utility as sealants.
Such compositions have found wide applicability for
use as sealants in bathrooms, in the home or in other
buildings. Thus, one such type of composition, and
specifically the acetoxy compositionl has long been
advertised as a bath tub caulk and sealant. However,
it was that there was one disadvantage in such RTV
sealants when they were utilized in bathrooms, and
specifically near the bath tub, or shower, or other
places where moisture was prevelant,-and that was that
fungi would grow on the sealant. Accordingly, since
silicone elastomers naturally allow the growth of
fungus, the growth of fungus would prevade and the
silicone sealant in the cured state would become
unsightly. Accordin~ly, it became evident that there
had to be utilized a fungicide in such RTV silicone
sealants so as to prevent the growth of fungus on such
sealants especially when such sealants were to be
utilized in the bathroom. An e~ample~of a fungicide
that was early utilized with acetoxy one-component RTV
sealants was 10,10'-Oxybisphenoxarsine. While this
v

' 1727gl
60SI-348
-- 5 --
fungicide was a very effective fungicide and prevented
the growth of fungus on RTV sealants, it had the
disadvantage that it turned yellow after a time when
the sealant was exposed to ultraviolet light, such as
sunlight. Ac ordingly, it was desired to find a more
suitable fungicide for RTV sealants which would make
the sealant in the cured state mildew resistant. In
such a search for various types of fungicides, there
were tested some of the fungicides disclosed in the
article entitled "Non Mercurial Fungicides" by Post,
et al., found on page ~ 1 ~ rough 38 of the September
1976 issue of Modern Pa~n and Coatings. In addition
to these fungicides, many other fungicides were looked
at. However, with the exception of the compounds
disclosed below, such fungicides do not perform properly.
Accordingly, most fungicides when they were tested
would degrade the shelf lifeiof the composition, that
is, the uncured composition after it has been heated
at 50C for three months, which was equivalent to
storage for 2 years at room temperature, would cure in
a very soft state or not cure at all and they physical
properties of the compositions that cured would be
very poor.
In another aspect, some fungicides cause the
adhesion or self-bounding properties of the RTV
sealant to suffer. AccordinglyJ it was highly
unexpected among the many fungicides that were tried
that the fungicides disclosed below would function very
effectively as a mildew resistant additive which would
prevent the composition from growing fungus and which
would not effect the curing properties of the uncured
composition and the physical properties of cured
composition.
Accordingly, it is one object of the present
invention to provide for room temperature vulcanizable
.

1 11 7279 1
60SI-348
silicone rubber composition which is mildew resistant.
It is another object of the present inventlon
to provide a process Eor forming a room temperature
vulcanizable silicone composition that is mildew
resistant.
It is yet an additional object of the present
invention to provide an effective fungicide for the
room temperature vulcanizable silicone rubber
compositions which does not effect the physical
properties of the cured composition.
It is still another object of the present
invention to provide for a fungicide for room-
temperature vulcanizable silicone rubber compositions
which does not effect the shelf life of the silicone
composition.
It is yet a further object of the present
invention to provide for a fungicide for a room
temperature vulcanizable silicone rubber composition
which does not effect the tack free time of the uncured
silicone composition.
It is yet another object: of the present
invention to provide for a fungicide for a room
temperature vulcanizable silicone rubber composition
that does not effect cure time of the uncured composition
~5 and wherein the cured composition does not yellow upon
exposure to ultraviolet light.
These and other object of the present invention
are accomplished by means of the disclosure set forth
herein and below.
Summary Of The Invention
In accordance with the above objects there
is provided by the present invention a mildew resistant
room temperature vulcanizable silicone rubber
composition comprising tA) 100 parts by weight of a
silanol end-stopped diorganopolysiloxane of a viscosity

1 1 72'~9 1
60SI-348
varying from lO0 to 500,000 centipoise at 25C where
the organo group is a monovalent hydrocarbon radical;
(B) from 0.01 to 15 parts by weight of a cross-linking
agent, (C) from 0.01 to lO parts by weight of a curing
catalyst; and, (D) an effective amount of a fungicide
of the formula,
O R
(1) R - ~ S C
"
O Rl
; where R is selected from the class~ con~isting of
hydrogen, halogen, and alkyl ~ ~a~rof l to 4 carbon
atoms and Rl is selected from the class consisting of
hydrogen, iodine, and alkyl radicals of l to 4 carbon
atoms. Preferably there is utilized from 0.01 to 2 parts
by weight of a fungicide where the fungicide is an
organic sulfone compound. While this fungicide may be
utilized both with one component and two component
compositions, it is most preferably utilized with one
component room temperature ~ulcanizable silicone rubber
compositions wherein the cross-linking agent either an
acetoxy functional silane or an alkoxy functional
silane, or 2-ethyl hexanoxy functional silane.
Description Of The Preferred Embodiment
_
There must be present in the composition an
effective amount of the fungicide of Formula (1). In
the formula, R is selected from the class consisting
of hydrogen and any monovalent hydrocarbon radical and
also halogen. Most preferably R is selected from the
class consisting of hydrogen, halogen and alkyl radicals
of l to 4 carbon atoms, such as methyl ethyl propyl,
butyl. With respect to the halogen groups, preferably
the halogen is either chlorine, bromine, or iodine and
more preferably chlorine. In the most preferred

1 1 7~7g 1 60SI 348
-- 8 --
embodiment, R is selected from the hydrogen, chlorine
and methyl groups. In the same respect R can be
selected from the class consisting of hydrogen, iodine,
and alkyl radicals of 1 to 4 carbon atoms such as
methyl, ethyl, propyl, and butyl. Most preferably, Rl
is selected from the class consisting of hydrogen, iodine,
and alkyl radicals of from 1 to 4 carbon atoms. Most
preferably Rl is selected from the class consisting of
hydrogen and iodine radicals. There are two preferred
fungicides within the scope of Formula (l). First
preferably the fungicide within the scope of Formula (1)
has the formula,
O H
(2) 3 ~ S C
O
Diiodomethyl-p-tolyl sulfone is the-most preferred
compound within the scope of the present invention.
~ less preferred but still desirable compound
within the scope of the present invention is a fungicide
having the formula,
O H
(3) Cl ~ S - C _ I
O E~
The above two compounds are the most preferred
compounds within the scope of the present invention; however,
as pointed out previously, any compound within the scope
of Formula (1) will be suitable as a fungicide in the
composition of the instant case, the most preferable
compound being the compounds of Formulas (2) and (3).
These compounds are well known compounds which
are available from Abbott Laboratories, Inc. of Chicago,
Illinois. One preferred process for making such fungicides
,.,

1 17~'~gl
60SI-348
is disclosed in UOS. Patent No. 3,657,353, A.J. Crovetti,
issued April 11, 1972. This is not the only method for
making the compounds in the instant case. There are
other processes for producing such compounds. It should
be noted that in the compositions of the instant case
there only need be an effective amount of the fungicide
in order for the composition to be mildew resistantO The
effective amount varies somewhat from composition to
composition. ~lore specifically, it is preferred that
there be present from 0.001 to 2 parts by weight of
fungicides per hundreds by weight of a base silanol
end-stopped polymer in the RTV composition. Most
preferably, there may be utilized anywhere from .05 to
0.6 parts per 100 parts of the base silanol polymer of
the fungicide in accordance with the instant invention.
It should be noted that on the upper limit there is no
limitation except the additional amounts of fungicide
do not serve any useful purpose and increase the cost
of the composition. Further, in some cases an increase
in the amount of fungicide over the above two part limit
may effect the shelf life of the composition.
~, Such fungicides are sold by Abbott Laboratories,
Inc., Chicago, Illinois, under the trade ~a~e of Amical.
Preferably when such fungicides axe added to RTV
compositions, they are added to form a dispersion of the
fungicide in butylated hydroxy toluene. The butylated
hydroxy toluene acts as a color stabilizer for the
fungicide. It has been noted that without such a color
stabilizer, in some-cases the fungicide will cause the
composition to turn yellow upon being heat aged at
50C for 3 months which is equivalent to a shelf storage
period of 2 years at room temperature. Preferably, -the
dispersion is anywhere from 5 to 95% by weight concentration
of the fungicide in 95 to 5% by weight of the butylated
hydroxy toluene color stabilizer.

`~ t72791
60SI-348
-- 10 --
The fungicide of the instant case may be
utilized with any room temperature vulcanizable silicone
rubber composition. In such condensatio~ curing room
temperature vulcanizable silicone rubber compositions,
the base polymer is the silanol end-stopped
diorganopolysiloxane polymer having a viscosity varying
from 100 to 500,000 centipoise at 25C with the organo
group as selected from any monovalent hydrocarbon
radical. More preferably, such a compound has the
formula, R7
I
(4) HO - SiO - - H
R8 t
where R7 ancl R8 are select~ ~d from monovalent hydrocarbon
radicals and t is such that the viscosity of the polymer
varies from 100 to 500,000 centipo:ise at 25C and more
preferably varies from 100 to 200,000 centipoise at
25C. The radicals R7 and R8 are independently selected
from monovalent hydrocarbon radica:Ls and may be selected
from alkyl radicals of 1 to 8 carbon atoms such as methyl,
ehtyl, etc., cyclo alkyl radicals such as cyclohexyl,
cycloheptyl, etc; mononuclear aryl radicals such as phenyl,
methylphenyl, etc.; alkenyl radicals selected from the
class of vinyl, allyl, etG,; and fluoro alkyl radicals
such as 3,3,3-trifluoropropyl. Most preferably, R7 and
R8 as well as the organic group in the definition of the
diorganopolysiloxane polymer are selected from the alkyl
radicals, phenyl radicalsl vinyl radicals, and fluoralkyl
radicals.
In one type of RTV composition per 100 parts by
weight of the silanol end-stopped diorganopolysiloxane
base polymer, there is utilized from 0.01 to 15 parts
by weight of a cross-linking agent and from 0.01 to 10

1 172791
60SI-348
parts by weight of a curing catalyst. The type of cross-
linking agent will vary depending on the type of
composition it is. Accordingly, in certain types of
composition, the cross-linking agent has the formula,
(5) R Si (O C O R )3
where R2 is an alkyl radicals of 1 to 8 carbon atoms and
R3 is a monovalent hydrocarbon. In one type or common
RTV composition, the compound within the scope of the
formula is methyl triacetoxy silane. Triacetoxy silane
is the cross-linking agent. Preferably, there is
utilized as a curing catalyst a metal salt of a
carboxylic acid with a metal varying from lead to
magnesium in the Periodic Table. Most preferably,
the metal salt is a tin salt of a carboxylic acid such
as a dibutyl tin dilaurate. However, for more
information as to such compounds, one is referred to
the patent literature for the different types of curing
catalyst that may be utilized with methyl triacetoxysilane
as the cross-linking agent. In such a composition per
100 parts by weight of the silano] base polymer there
may be utilized from 5 to 200 parts by weight of a
filler. The filler may be selected from reinforcing or
extending fillers. Examples of reinforcing fillers are
fumed silica and precipitated silica which can be
treated or untreated but are preferably treated with
cyclopolysiloxane polymers silazanes and the like.
Extending fillers are titanium dioxide, lithopane,
zinc oxide, zirconium silicate, silica aerogel, iron
oxide, diatmaceous earth, calcium carbonate, glass
fibers, magnesium oxide, chormic oxide, zirconium
oxide, aluminum oxide, crushed quartz, calcined clay,
asbestos, carbon, graphite, cork, cotton, synthetic
fibers, and so forth~ Silicone or silazane treated
fillers such as those`described in Lucas UOS. Patent No.

~ 1~2791 60SI-348
2,938,009 - issued May 24, 1960, Lichtenwalner U.S.
Patent No. 3,004,859 - issued October 17, 1961 and
Smith U.S. Patent No. 3,635,743 - issued January 18,
1972 are particularly suitable for use in the RTV
composition of the present invention. These are generally
employed in amounts from about 5 to about 200 parts and
preferably from about 10 to 100 parts by weight per 100
parts of a silanol chain stopped diorganopolysiloxane
polymer. The only limitation on the use of such fillers
is the viscosity limitation on the uncured composition
that it is necessary to meet. In particular, reinforcing
fillers such as fumed silica and precipitated silica even
though treated will increase the viscosity of the
uncured composition considerably if high loadings of
such filler is used. In such compositions, there may be
utilized other additives such as adhesion promoters, flame
retardant additives, and so on which are evident in the
RTV silicone patent art. Such adclitives may be present
in the composition of the present case as long as it
does not interfere with fungicidal activity. It should
be noted that in such acetoxy curi.ng RTV composition, it
has not been found the fungicide activity is not
effected by any of the traditional additives.
I~ the cross-linking agents of Formula (5),
R3 may also be an alkyl radical of 6 to 30 carbon atoms.
Specifically novel compositions have recently been
discovered in which the cross-linking agent is ~th~l
meth~-tris-(2-ethyl, hexanoxy) silane as disclosed in
the patent application of ~.D. Beers, Serial No.
330,424, filed on June 22, 1979. It has been found that
these compositions are not as corrosive as the acetoxy
curing composition and also do not give off pungent
odors. A curing catalyst with such a composition or
cross-linking agent and again with a silanol base
polymer is preferably a tin salt of carboxlyic acid
.

~ l 727~1
- 13 - 60SI-348
in which two preferred embodiments are dibutyl tin
dioxide and dim~thyl tin dineodeca~oate as disclosed
in the foregoing Canadian Application Serial No. 330,424.
A desirable ingredient in this composition per 100 parts
by weight of base polymer is from 2 to 20 parts by weight
of a fluid polysiloxane containing a high degree of tri-
functionality, tetrafunctionality, or a mixture of tri-
and tetrafunctionality and comprising:
(i) from 25 to 60 mole percent of monoalkyl
siloxy units, siloxy units or a mixture of such units;
(ii) from 1 to 6 mole percent of trialkylsiloxy
units; and
(iii) from 37 to 74 mole percent of dialkylsiloxy
units, the polysiloxane containing from about 0.1 to 2 parts
by weight of silicone-bonded hydroxyl groups.
These compositions have high temperature
stability and oil resistance, and are admirably suited
for making silicone rubber gasketing. In the composition
there is preferably utilized from 5 to 30 parts by weight
of silica fillers such as fumed silica and precipitated
silica, and from 5 to 170 parts by we~ight of extending
filler. There is preferably used from 5 to 170 parts by
weight of reinforcing filler such as calcium carbonate.
Too much of ~he reinforcing filler is not utilized since
the composition would have unduly increasing viscosity in
the uncured state. It should be noted that the fumed
silica is utilized in the composition to some extent as
a sag control additive rather than as a reinfoxcing
additive. In addition, as a sag control additive
there may be added from 0.03 to 2 parts by weight of a
polyether as a surfactant per 100 parts by weight of a
silanol end-stopped polymer. For more complete
disclosure as to the use of such polyether sag control
additives one is referred to the disclosure of
35 Weight et al Canadian application Serial No. 348,740 entitled

~ 1 7279 ~L 60SI-348
- 14 -
"Room Temperature Vulcanizable Silicone Rubber Compositions
with Sag Control" filed on March 28, 1980. With such
compositions as well as the acetoxy composition, there
may be utilized anywhere from 0.1 to 3 parts by weight
of an adhesion promoter se~ected f,rom the class consisting
Y~0~S
3~` ' of silyl maleates, silyl umcratc3, and silyl succinates.
The formula of the particular embodiment of such
materials will not be disclosed herein since they are
the subject of Smith et al, Canadian patent application,
Serial No. 359,263 filed on August 29, 1980 entitled
"Self-Bonding Room Temperature Vulcanizable Silicone
Rubber Compositions'i. As disclosed in that patent
application, there can be utilized as a self-bonding
additive per 100 parts of a base silanol polymer from
0.1 to 3 parts by weight of a self-bonding additive
selected from the group consisting of:
R6 C - Z - R - Si Rn (M)3-n
R6 _ C - Z - G
R - C - Z - Si Rn (M)3 n
G - Z C R6 and
R6 CH - Z - R - Si Rn (M)3-n
R CH - Z - G
where Z is selected from O , phenylene, O, COHN and
ll ll
C - O C
CONR2 & ~s selected from the class consisting of hydrogenr
R', R SiRn (M)3 n where R' is selected from monovalent
hydrocarbon radicals and halogenated monovalent
hydrocarbon radicals, R and R4 is a divalent.hydrocarbon
radical, R is selected from monovalent hydrocarbon
radicals and halogenated monovalent.hydrocarbon radicals,
M is selected from R O and R3 C-O ~ radicals R is selected

~ 1 7 27g 1 60SI-3~8
~ 15 -
from monovalent hydrocarbon radicals and halogenated
monovalent hydrocarbon radicals, R6 is selected from
hydrogen, and alkyl radicals of up to 10 carbon atoms
and n is a whole number that varies from 1 to 3, and
self-bonding polysiloxane additives seIected from the
group consisting of the formulas,
~ R6 _ C - Z - R ~ Rb SiO4-a-b,
~ R - C - Z - G' ~ a
R6 _ C - Z - R ~ Rb SiO~ a-b'
G' - Z - C - R6
~/
,~ a
~ R6 _ CH - Z - R ~ b 4-a-b
~ R6 _ CH - Z - G ~
where G' is selected from the class consisting of
hydrogen, R' add R HcRd Si(3-c-d/2)
R and R and R are as previously defined, a varies
from 0.005 to 2.0, b' varies from 1.0 to 2.5, the sum
of a+b varies from 1.005 to 3.0, c varies from 0 to
1.0, d varies from 1.0 to 2.5 and the sum of c+d varies
from 1.0 to 2Ø
There may be utilized other additives in such
compositions such as iron oxide, various plastizers. It
should be noted that none of these additives affect the
fungicidal activity of the fungicides or that the fungicide
of the instant case be utilized in such compositions to
produce an effective mildew resistant RTV sealant. In
another aspect and in another preferred embodiment
.

1 172791
60SI-348
- 16 -
within the scope of the instant case, the cxoss-linking
agent can be alkyl trialkoxysilane and the curing
catalyst can be a titanium chelate. Preferably, the
alkyl trialkoxy silane is methyl trimethoxy silane and
the titamium chelate catalyst is one of those disclosed
in Beers U.S. Patent 4,100,129.
Especailly important are partially chelated
organometalic esters and particularly titanium compounds
of the formula:
o~
R80
wherein R is hydrogen, or an organic radical of up to 8
carbon atoms selected from hydrocarbyl, halohydrocarbyl, or
carboxyalkyl; R5 is a radical of up to 8 carbon atoms
selected from hydrocarbyl, halohydrocarbyl and cyano-lower
alkyl; R6 is selected from same group as R4 and in
addition, from halo, cyano, nitrol carboxy ester, or acyl
and hydrocarbyl substituted by halo, cyano, nitro,
carboxy ester and acyl, the total number of carbon atoms
in the R4 and in the R6 substituted alkanedioxy radical
being not more than about 18; R7 is selected from hydrogen
or an organic radical of up to 8 carbon atoms selected
from hydrocarbyl, halohydrocarbyl, or acyl and, when taken
together with R5 forms together with the carbon atoms to

~ 172791
- 17 - 60SI-348
which they are attached a cyclic hydrocarbon substituent
of up to about 12 carbon atoms or such a substituent
substituted with one or more of a chIoro, ni-tro, acyl cyano
or carboxy ester substituents; X is a radical of up to 20
carbon atoms selected from hydrocarbyl, halohydrocarbyl,
cyanoalkyl, alkoxy, haloalkoxy, cyanoalkoxy, amino or
ether and polyether groups of the formula -(CqH2qO)VR
where q is from 2 to 4, v is from O to 20 and R is
as defined above, a is 0 or an integer of up to 8 and,
when a is 0, the ,~C - R2 ~roups are bonded to each other
in a cyclic fashion, and R8 is a radical of up to 8
carbon atoms selected from hydrocarbyl, halohydrocarbyl or
cyano-lower alkyl. In the composition preferably there is
utilized either extending or reinforcing fillers, but most
preferably there is utilized from 5 to 20 parts by weight
of a reinforcing silica filler and from 5 to 180 parts by
weight of an extending filler such as calcium carbonate.
Accordingly, in such an alkoxy curing composition there
may be plas-ticizers such as from 1 to 50 parts by weight
of a plasticizer which is a triorganosilyl end-stopped
diorganopolysiloxane of a viscosity varying from 10 to
10,000 centipoise at 25C and where the organo group is
a monovalent hydrocarbon radical and preferably selected
from alkyl radicals, mononuclear aryl radicals, alkenyl
radicals, cyclo alkyl radicals, and fluoroalkyl radicals.
More preferably the organo group in such plasticizers is
an alkyl radical of 1 to 8 carbon atoms, such as methyl or
phenyl, more preferably being methyl. Most preferably,
the plasticizer has a viscosity varying from 10 to 1,000
centipoise and is dimethylpolysiloxane which is trimethyl-
siloxy end-stopped. Such alkoxy curing RTV compositions may
be an adhesion promoter generally from 0.2 to 2 parts by
weight of an adhesion promoter of nitrogen containing
compounds such as acetonitrile. The preferred adhesion
promoters for the alkoxy curing one-part systems have
the formula

1 172791
60SI-348
- 18 -
(R )3 b~b - Si - R9 - N / \ N~
~ \ N ~ ~
G
wherein G is the same as R10, hereinafter defined,
a (R 10)3 b - Rb - Si - R radical, styryl, vinyl,
allyl, chloroallyl or cyclohexenyl; R9 is a divalent
radical selected from alkylenearylene, alkylene,
cycloalkenyl and halosubstituted such divalent radicals;
R10 is a radical oE up to 8 carbon atoms selected from
hydrocarbyl or halohydrocarbyl and Rll is a radical of
the type defined for R10 and also cyano lower alkyl,
and b is 0 to 3.
The most preferred such adhesion promoters
: are 1,3,5-tris-trimethoxysilylpropylisocyanate and
bis-1,3-trimethoxysilylpropylisocyanurate.
In addition to fillers and adhesion promoters,
the present compositions can also include a thixotrope
or viscosity depressant in the form of from 0.3 to 20
parts by weight of a low molecular weight linear
polydiorganosiIoxane. A preferred class of such
viscosity depressants is th~ose of the formula,
f R13 ~
R n I i ` 15
J
~ R13 ~
,~ ~ ~ x
: .. -:: . :
, . -. . , :
: ~ :
'

! 172791
60SI-348
-- 19 --
wherein R12 and R13 are each organic radicals of up to
8 carbon atoms selected from hydrocarbyl, halohydrocarbyl
and cyano lower alkyl, R14 and R15 are, independently,
hydrogen or radicals as defined for R12 and R13, and x
has a value of from 2 to 46.
The most preferred such thixotropes are those
of the above formula wherein, in the viscosity depressant,
R14 and R15 are methyl, R12 and R13 are methyl or methyl
and phenyl in a ratio of about 70:30, and x is an integer
of from 3 to 50.
There may also be included in such compositions
additional conventional ingredients as flame retardant
stabilizing agents, pigments, reinforcing agents as
with the case with the prior art RTV compositions. As
long as the additive does not effect the mildew resistant
activity of the fungicide it can be utilized in the
composition of the instant case. It has been found
that most traditional additives that have been tested
in such compositions have not affected the mildew
resistant activity of the fungicides of the instant case.
The compositions of the instant case have been disclosed
as fungicides in the above for one component RTV
compositions. However, they can be utilized if desired
as fungicides for two component condensation curing RTV
compositions. Such compositions such as two component
RTV compositions comprise a base silanol end-stopped
polymer as disclosed above for -the one-component
systems and an alkyl silicate as a cross-linking agent,
such as, ortho silicates such as tetra, ethyl orthosilicate
and a partial hydrolysis product of such silicate. The
curing catalysts with such alkyl silicates are usually
utilized in the concentration of 0.01 to 10 parts by
weight per 100 of a silanol based polymer and the metal
salt of a carboxylic acid such as preferably a tin salt
of a carboxylic acid. One type o-f such catalyst that is

~ ~ ~2791 60SI-348
- 20 -
preferred for such compositions is, for instance,
dibutyl tin dilaurate. This composition has various
additives in them, such as, self-bonding promoters, deep
section cure additives, such as, water and various other
types of additives. An example of such composition is
to be found in Lampe and Bessemer, U.S. Patent 3,888,815
which issued June 10, 1975. It should be noted that
normally two component systems are not utilized in
applications where it is necessary that it be mildew
resistant but if it was necessary it may be made mildew
resistant. Accordingly, the mildew resistant fungicide
of the instant case may be utilized to render compositions
mildew resistant in the concentrations disclosed above,
that is, compositions other than the above one-component
systems. Accordingly, the fungicide of the instant case
can be utilized to render mildew resistant one-component
RTV systems in which the cross-linking agent is other
than the cross-linking agents disclosed above such as,
for instance, nitrogen functional cross-linking agents.
One component RTV systems utilizing a nitrogen functional
silane as cross-linking agent are ketoxime, and aminoxy
systems.
Accordingly, it is not the intent of the inventor
of the instant case to limit the use of this fungicide
with systems having only the cross-linking agents
disclosed above. The fungicide may be utilized as a
fungicide to render one component systems mildew
resistant where the cross-linking agent is other than the
cross-linking agents disclosed above.
The composition is prepared by first dispersing
or mixing the fungicide of the instant case in the butylated
hydroxy toluene and then making a master batch of such
dispersion with a portion of the silanol base polymer
and preferably with some fillers as to give the composition
consistency. When the composition is prepared, the base
.,

~ 1 ~2791 60SI-348
- 21 -
silanol and polymer with a filler in it such as a base
composition is mixed with fungicide dispersion or a
portion of the master batch of fungicide dispersion and
when the catalyst and other ingredients are added
the mixing is carried out in a substantially anhydrous
state so when the final mixture is obtained, a one-
component RTV system in a substantially anhydrous state.
When it is desired to apply the composition, the seal of
the package is broken, the composition is applied,
and the composition will cure to a silicone elastomer
upon the hydroylsis of the cross-linking agent by
atmospheric moisture. Cure to a tack-free state is
obtained in about 10 to 30 minutes in such ~omposition
normally and the final cure takes place in about 1 to 3
days.
The two component composition is prepared in
the same way that is to obtain a master batch of the
silanol polymer, filler and the fungicide with a color
stabilizer and then this master batch is added to a
base silanol polymer as a single c:omponent which is
packaged separately from the cata]yst c mponent when
it is desired to cure the composit:ion, the two components
are mixed and applied whereupon the mixture will cure to
a silicone elastomer. With respect to the one component
system, irrespective of how the fungicide is added to
the composition, it should be noted that it is preferably
first dispersed in the color stabilizer before it is
added to the composition and that the one-component
composition be packaged in a substantially anhydrous
state. The addition of the ingredients is not normally
critical in the formulation of such compositions.
The examples below are given for the purposes
of illustrating the present invention and are not given
for any purpose of setting limits and boundaries to the
instant invention. All parts in the examples are by weight.

1 ~72~91
- 22 - 60SI-348
Ex~ample 1
There was prepared a base formulation comprising
1100 parts by weight of a silanol end-stopped dimethyl-
polysiloxane polymer of 4200 centipoise viscosity at 25C.
With this was mixed 2200 parts by weight of fumed silica
treated with octomethyl cyclo tetrasiloxane. To this was
added 154 parts by weight of mono/di/tri-functional (M/D/T)
silicone oil containing approximately 5 mole percent
trimethyl siloxy units, 20 mole pèrcent monomethyl
siloxy units, 75 mole percent dimethyl siloxy units and
approximately 0.5 weight percent hydroxy units. This above
base composition, after it was mixed, was then dried for
1 hour at 100C at 5 millimeter vacuum to remove water.
Then there was prepared a dispersion by adding 10 parts
of the fungicide to 185 parts silanol end-stopped dimethyl
polysiloxane polymer of 600 centipoise viscosity at 25C,
and then was added 5 parts o~ the octamethyl cyclotetra-
siloxane treated fumed silica and 10 parts by weight of
diiodomethyl-p-tolyl sulfone. The mixture was mixed
on a high speed Eppenbach mixer for 30 minutes to achieve
the actual dispersion. There were added 25 parts of the
sulfone dispersion to 500 parts o~ the base composition.
This mixture of ingredients was catalyzed at 24.5 parts
of a catalyst mixture consisting of 79.1% of methyl
triacetoxy silane, 19.8% of ditertiary butoxy diacetoxy
silane, and 1.1% of dibutyltindiacetate. The mixture
was catalyzed at 100 strokes on a Semco catalyzer.
Samples of catalyzed sealant were tested at GE Elect~nics
Lab, Electronics Park for fungicidal activity. The
sealant showed excellent fungus resistance to Aspergillus
niger, Aspergillus flavus, Aspergillus teneus, Myrotecium
verrucaria and MemmieIla eschinata.
Example 2
~ . ._
There was prepared a base composition comprising
600 parts of a silanol terminated dimethylpolysiloxane

! 172791 60SI-348
- 23 -
polymer of 105,000 centipoise viscosity at 25C, to
which was added 30 parts by weight of methyl phenyl
trimethylsiloxy end-stopped oil of 10 centipoise
viscosity at 25C, 72 parts by weight of fumed silica
treated with octoamethyl cyclo tetrasiloxane, 720 parts
of stearic acid treated calcium carbonate, 230 parts
of a trimethylsiloxy end-stopped dimethyl polysiloxane
fluid at 100 centipoise viscosity at 25Cr 36 parts of
titanium oxide and 11.8 parts of the sulfone fungicidal
dispersion of Example 1. The base was co-mixed at
room temperature with 6mm vacuum on a change can mixer
for 6 hours to achieve maximum dispersion. One thousand
parts of the base was catalyzed by 100 strokes in a
pressure Semco catalyzer with a mixture comprising 8.0
parts of 1,3-propane dioxytitanium bis(acetyl aeetonate),
15.0 parts of methyltrimethoxysilane and 7.5 parts of
1,3,5 tris (Trimethoxy silyl popyl) iscoeyanurate. This
composition was then tested for fungicidal activity and
showed exeellent resistanee to the mixed fungieide
eulture deseribed in Example 1.
Example 3
There was mixed 1000 parts of a silanol
end stopped dimethyl polysiloxane polymer of 3100
centipoise viscosity of 25C. To this there was added
2.0 parts of ethylene oxide/propylene oxide polyether
surfactan~ as a sag control additive. To this there was
added 100 parts by weight 45 eentipoise viseosity at
25C silanol terminated polydimethyl siloxane M/D/T
silicone oil eontaining approximately 5 mole pereent
trimethylsiloxy, 20 mole percent monomethylsiloxy,
75 mole percent dimethyl siloxy units and approximately
0.5 weight pereent hydroxy eontent. To this mixture
there was added 500 parts of stearie aeid treated
calcium carbonate, 200 parts of oetamethyl
eyclotetrasiloxane treated fumed silica and 40 parts of

~ ~ 7~791 60SI 348
- 2~ -
of a masterbatch containing 90 percent by weight of
titanium oxide and 10 percent by weight of a dispersion
of diiodmethyl-p-tolyl sulrone which was dispersed
with butylated hydroxy toluene as a color stabilizer
(there was 80 percent by weight of the sulfone per 20
percent of butylated hydroxy toluene). 1400 parts of
the base mixture of above was catalyzed with 100 strokes
on a Semco catalyzer with 104 parts of a mixture
comprising 70.89 parts of methyl tris (2-ethyl-hexanoxy~
silane, 31.52 parts of bis(tri-methoxysilypopyl) fumerate,
and 1.58 parts of dimethyl tin dineodecanoate. Again,
the fungicidal activity of the cured composition to the
fungus culture of Example 1 was excellent.
Example 4
There was mixed 1000 parts of a silanol
end-stopped dimethyl polysiloxane polymer o~ 13,000
centipoise viscosity at 25C. To this there was added
2.0 parts of ethylene oxide/propylene oxide polyether
surfactant as a sag control additive. To this there was
added 100 parts by weight 45 centipoise viscosity at
25C of a silanol terminated polydimethyl siloxane
M/D/T silicone oil containing approximately 5 mole
percent trimethylsiloxy, 20 mole percent monomethylsiloxy,
75 mole percent dimethyl siloxy units and approximately
0.5 wei~ht percent hydroxy content, 200 parts of a
trimethylsiloxy end-stopped dimethyl polysiloxane fluid
of 100 centipoise viscosity at 25C, 200 parts of
octomethyl cyclotetrasiloxane treated fumed silica
and 40 parts of a masterbatch containing 90 percent
by weight of titanium oxide and 10 percent by weight
of a dispersion of diiodomethyl-p-tolyl sulfone which
was dispersed with butylated hydroxy toluene as a color
stabilizer to which there was 80 percent by weight of
the sulfone per 20 percent of butylated hydroxy toluene
in a color stabilizer. 1400 parts of the base mixture
. .

~ 1 727~1 60SI-348
- 25 -
of above was catalyzed with 100 strokes on a Semco
catalyzer with 104 parts of a mixture comprising 70.89
parts of methyl tris (2-ethyl-hexanoxy) silane, 31.52
parts of bis(tri methoxysilylpropyl) fumerate, and
1.58 parts of dimethyl tin dineodecanoate. Again, the
fungicidal activity of the cured composition to the
fungus culture of Example 1 was excellent.
Example 5
There was mixed 1000 parts of a silanol
end-stopped dimethyl polysiloxane polymer of 4100
centipoise viscosity at 25C. To this there was added
2.0 parts of ethylene oxide/propylene oxide polyether
surfactant as a sag control additive. To this there
was added 100 parts by weight of a 45 centipoise viscosity
at 25C silanol terminated polydimethyl siloxane M/D/T
silicone oil containing approximately 5 mole percent
trimethylsiloxy, 20 mole percent monomethylsiloxy, 75
mole percent dimethyl siloxy units and approximately
0.5 weight percent hydroxy content. To this mixture
there was added 500 parts of stearic acid treated
calcium carbonate, 200 parts of octomethyl
cyclotetrasiloxane treated fumed silica and 40 parts
of a masterbatch containing 90 percent by weight
of titanium oxide and 10 percent by weight of a dispersion
of diiodomethyl-p-tolyl sulfone which was dispersed
with butylated hydroxy toluene as a color stabilizer
to which there was 80 percent by weight of the sulfone
per 20 percent of butylated hydroxy toluene in a color
~; stabilizer. 1000 parts of the base mixture of above
was catalyzed with 100 strokes on a Semco ~7atalyzer with
60 parts of acetoxy ethyltris (methyl ethyl imino-oxy)
silane and .66 parts of dibutyltindilaurate. Again
the fungicidal activity to the fungus culture described
in Example 1 was excellent.