CA1172791A - Mildew resistant rtv silicone compositions - Google Patents
Mildew resistant rtv silicone compositionsInfo
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- CA1172791A CA1172791A CA000375696A CA375696A CA1172791A CA 1172791 A CA1172791 A CA 1172791A CA 000375696 A CA000375696 A CA 000375696A CA 375696 A CA375696 A CA 375696A CA 1172791 A CA1172791 A CA 1172791A
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Abstract
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
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
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 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
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 ,, . .
~ 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 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 .
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 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 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
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 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
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 ,, . .
~ 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 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 .
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 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 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
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 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 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
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 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 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 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,
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 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 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 "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 .
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~
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 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 (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 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 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 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 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 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 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.
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 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 "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 .
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~
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 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 (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 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 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 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 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 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 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.
Claims (42)
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 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.
(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 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
4. The composition of claim 2, wherein the fungicide has the formula
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 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.
(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.
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 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.
(C) from 0.01 to 10 parts by weight of a curing catalyst;
and (D) an effective amount of a fungicide of the formula 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.
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 .
25. The process of claim 23, wherein the fungicide has the formula .
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.
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.
(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 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000375696A CA1172791A (en) | 1981-04-16 | 1981-04-16 | Mildew resistant rtv silicone compositions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000375696A CA1172791A (en) | 1981-04-16 | 1981-04-16 | Mildew resistant rtv silicone compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1172791A true CA1172791A (en) | 1984-08-14 |
Family
ID=4119761
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000375696A Expired CA1172791A (en) | 1981-04-16 | 1981-04-16 | Mildew resistant rtv silicone compositions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1172791A (en) |
-
1981
- 1981-04-16 CA CA000375696A patent/CA1172791A/en not_active Expired
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