CA2085652A1 - Silicone rtv's exhibiting rapid adhesion development - Google Patents

Abstract

ABSTRACT OF THE INVENTION

There is disclosed a two component silicone adhesive exhibiting excellent rapid adhesion to substrates prepared by curing a chain stopped polydiorganosiloxane with a catalyst component comprising hexamethyldisilazane (HMDZ) or other suitable silylating.gamma.
agent.

Description

5~

SILICONE RltV' S E3~IBITI21G RP~PID AD~ESION DEVELOPMENT

The present invention relates to compositlons for enhancing the bonding of silicones to substrates.
More particularly, it relates to a self-bonding, two part, room temperature vulcani2able (RTV) silicone composition comprising a silylating agent.

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Room temperature two-part ~ulcanizing silicone compositions are presently widely known. For example, Hyde, United states Patent No. Z,571,039 di closcs preparing an organosiloxane by compounding a readily deformable acid pol~mer comprising a polysiloxane and an acidic compound with a filler, and then reacting the compounded material with a silane o~ the formula RnSi(OR' )~-n where R is a monovalent hydrocarbon radical free of aliphatic unsaturation, ~' is an al~yl radical of less than 9 carbon atom~ and n has a value of 0 to 1.
~erridge, United State~ Pate~t No. 2,843,555 disclo c~ an organopolysiloxan~ composition convertible at room temp~rature to the cured, solid, Pla~tic state comprising (a) a linear, fluid organopolysiloxane containing terminal silicon-~onded hydroxy groups and havin~ an average of about two oryanic group~ per silicon atom, (b) an alkyl silicate, and (c) a metallic salt of an organic car~ox~lic acld.
The compositlons are u~2ful as sealants, electrical insulation, coa~ing~, dental cementt caulking : - compounds, expansion joints, gaskets, shock absorbers, adhesive3 and in many o~her applications.

~ ¢ ~ 3~

Presently, two-part condensation cure RTV's are typically comprised of an "A" component consist~ng of (1) a dihydroxy or silanol terminated polydiorganosiloxane;
(2) a reinforcing filler such as CaC03~ fumed silica, or ground quartz; and (3) water; and a "B" component containing (1) an adhesion promoter; (2) a T or Q
functional crosslinker; and (3) a condensation cure catalyst. Combining the "A" an~ "B" components in a pred~ter~ined ratlo initiates the cure.
It i~ also known (e.g. from published Japanese Patent application No. 1-152532, filed June 15, 19~9) that high strength and high modulus water resistant silicone rubber compositions can be obtained by adding to a dealcoholization-type RTV silicone rubber composition, a colloidal calcium carbonate filler surface-treated with a rosin acid.
Despite the improved adhesion of the silicones of the prior art, silicone adhe~ives continue to be precluded from many indu~trial application~ due to their slower rate of adhesion. It would therefore represent a notable advance in the state of the art ~f a two-part silicone adhe~ive could be prepared having an increased rate at which the silicone adhesive develops 100%
cohe3ive fa~ lure to plastic substrates, such as polycarbonate, without adversely affecting other cure or physical properties.
It has now surprislngly been ~ound that the addition of a silylat1ng agent to the "B" component of a two part sillcone adhesive significantly reduces the time required for the sealant to develop 10~% cohesive failure to polycarbonate.

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Furthermore, the addition of a sllylatlng agent such a~ HMDZ does not inhibit the cure of the interior portions of a large volume of sealan (no "deep section"
cur~ inhibition). This is particularly surprising since it is well known to those skilled in the art that HMDZ is ~n active silylating agent which converts a reactive silanol polymer to a chemically iner~ M-~topped fluid as shown in (I).
SiOH + (cH3)3siNHsi(cH3)3 ~ iOSi(CH3)3 + H2NSl(CH3)3 (I) It is expected that the silylation reaction of (I) would favorably compe~e wi~h the condensation (~cure~3 reaction shown in (II).

SiOH + (RO)3SiOSi --~ SlOSi(O~2OSi + ROH (II) where R is methyl, ethyl, propyl, etcO
It has been found that polycarbonate samples sealed with prior art silicone sealants tend to lose their adhesion after either accelerated heat aging or extended periods o~ time a~ room temperature. This adhesion loss has been attributed, at least in part, to 2S "crazing" of the polycarbonate by exposure to NH3 formed by the reaction of HMDZ with the condensation cure by-product, methanol. Surprisingly, it has now been found that no obvious polycarbonate "crazing" appears in polycarbonate specimen~ sealed with two part RTVs of the pr0~e~t invention having the neces~ary component-~ for ammonia formation, HMDZ and an alcohol (methanol, ethanol or propanol).

~ ccording to the present invention there is provided a self bonding room temperature vulcanizing composition having improved adhesion to substrates comprlsing: A. a polymeric component comprlsing (1) a silanol chain stopped polydiorganosiloxane; and (ii) an effective amount of water; and B. a catalyst component comprising (i) an effective amount of a silylating agent having at lea~t one labile or leaving monovalent or divalent group attached to silicon by silicon-nitrog~n linkages and which silylating aq~nt is select~d from the group consisting of silane and organopolysiloxane; (ii) an eff~ctive curing amount of a condensation cure catalyst; and (iii) an effective amount of a crosslinking agent. Preferably th~ polymeric component A of the RTV
composi~ion furth~r comprise~ A(iii) an effec~ive amount of a filler. Al~o pre~erably th* ca~aly~t component B of the RT~ composition further compri~e~ B~iv) an effec ive amount of an adhe~ion promoter.
Also accord~ng to the presen~ invention there is provided a method for forming 2 sel~ bonding room temperature vulcanizing composition having improved adhesion to substrates comprising: A. preparing a polymeric component c~mprising (i) a silanol chain stopped polydiorganosiloxane, and (ii) an ef~ective amount of water; and B. preparing a catalyst component compri~ing (i) an effective amount of a silyla~ing agent having at lea~t one lablle or leaving monovalent or divalent sroup a tached to s~licon by silicon-nitrogen linkages and which silylating agent î~ selec~ed from the group consisting of silane and organopolysiloxane; (ii) an effective curlng amount of a condensation cure ca~alyst; and (iil~ an ef~ec~ive amount of a crosslinking agQnt; and C. combin~ng and mixing A. and B. to cure the ~r,~ t'r~2 ~5~ o~SI-1340 polydiorganosiloxane. Pr~ferably the polymeric component prepared in step A furth~r comprises A~iii) an effective amount of a filler. Also preferably th~ catalyst component prepared in step B further comprises (iv) an effective amount of an adhesion promoter.
In pref~rred embodiments, ~he silanol terminated polydiorganosiloxane comprises a silanol terminated dimethylpolysiloxane; the silylating agent comprises hexamethyldisilazane; th~ condensation cure catalyst comprises a tin compound; the crosslinking agent is selected from tetra(n-propyl)silica~e, tetraethylsilicate, partially condensed ethylsilicate and methyltrimethoxysilane; the filler comprises ground and/or precipitated calcium carbonate, fumed silica, ground quartz or mixture~ thereof; and th~ adhesion promo~er i5 selected from gamma-glycidoxypropyltri-m~thoxysilane, 3-aminopropyl-triethoxy~ilane, 1,3,5-tris(3-trimethoxysilylpropyl)-isocyanurate and mixtures thereof.

DETAILED D~SCRIP~GN OF ~HE PRES-NI : ~N710N

The silanol chain-stopped polydiorganosiloxanes A(i) for use in the present invention may be represented by the formula-~Rl ~
t 1 2 \R /n wherein R~ and R2 are each organic rad~cals o up to 20, and pre~erably up to 8 carbon atom~, selected from hydrocarbyl, halohydrocarbyl and cyano lower alkyl and n i~ a number that varie~ generally from about 10 to about 15,000, preferably from 100 to 3,000, and more preferably from 300 to 1,500.

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The silanol chain-stopped polydiorganosiloxanes are well known in the art and they may be prepared by known methods, such as describ~d in Be~rs, United States Patent No. 3,382,205 and include composition containing different Rl an~ ~2 groupsO For example, in formula (1) the Rl groups can be methyl, while the R groups can be phenyl and/or beta-cyano-ethyl and/or trifluoropropyl.
Furthermore, within the scope of the definition of polydiorganosiloxane~ useful in thi~ invention are copolymers of various types of diorgansiloxane units, such as silanol chain-stopped copolymers of dimethyl-siloxane unit~, diphenylsiloxane units, and methylphenyl siloxane units,, or, for example, copolymers of dimethylsiloxane units, methylphenyl-siloxane units and methylvinyl siloxane units. Pre~erably, at lea~t 50% of the R1 and R2 groups of the silanol chain-stopped polydiorganosiloxane~ are alkyl, e.g. me~hyl group~.
In the above formula (1), Rl and ~2 can b~, for example, mononuclear aryl, ~uch as phenylt benzyl, tolyl, xylyl and ethylphenyl; halogen-sub~tltuted mononuclear aryl such as 2,5-dichlorophenyl, 4-bromophenyl, 2,5-difluorophenyl, 2,4,~-trichlorophenyl and 2,5-dibromo-phenyl; alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tertbutyl, amyl, hexyl, heptyl~ octyl; alkenyl such a~ vinyl, allyl, n-butenyl-l, n-butenyl-2, n-pentenyl-2, n-hexenyl-2, 2,3-dimethyl-butenyl-2, n-heptenyl; alkynyl such as propargyl, 2-butynyl; haloalkyl such a3 chloromethyl, iodomethyl, bromomethyl, fluoromethyl, chloroethyl, iodo~thyl, bromoethyl, fluoro~thyl, trichloromethyl, diiodoethyl, tribromomethyl, trifluoromethyl, dichloroethyl, chloro-n-propyl, bromo-n-propyl, 3,3,3-trifluoropropyl, iodoisopropyl, bro~o-n-butyl, bromo-tert-bu~yl, 1,3,3-trtchlorobutyl, 1,3,3-tribromobutyl~ chloropentyl, bromophenyl, 2,3-dichloropsntyl, 3,3-dibromophenyl, chlorohexyl, 1,4-dichlorohexyl, 3,3-dibromohexyl, r~

bromooctyl; haloalkenyl such as chlorovinyl~ bromovinyl, chloroallyl, bromoallyl, 3-chloro-n-butenyl-1, 3-chloro-n-pentenyl-l, 3-fluoro-n-heptenyl-1, 1,3,3-trichloro-n-heptenyl-5, 1,3,5-trichloro-n-octenyl-6, 2,3,3-trichloromethylpentenyl-4; haloalkynyl such as chloropropsrgyl, bromopropargyl; cy~loalkyl, cycloalkenyl and alkyl and halogen substituted cycloalkyl and cycloalkenyl such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 6-methyl-cyclohexyl, 3,3-dichlorocyclohexyl, 2,6-dibromocy~loheptyl, 1-cyclopentenyl, 3-methyl-1-cyclopentenyl, 3,4-dime~hyl-1-cyclopentenyl, 5-methyl-5-cyclopentenyl, 3,4-dichloro-5-cyclopentenyl, 5-(tert-butyl)-1-cyclopentenyl, 1-cyclohexenyl, 3-methyl-1-cyclohexenyl, 3,4-dimethyl-1-cyclohex0nyl; and cyano lower alkyl such as cyanomethyl, beta-cyanoethyl, gamma-cyanopropyl, delta-cyanobutyl and gamma cyanoisobutyl.
Further, i~ is contempla~ed that a mix~ure of various silanol chain-stopped polydiorganosiloxanes may also be employed as the silanol chain stopped polydiorganosiloxane component A(i).
The silanol chain-stopped polydiorganosiloxanes employed in the practice of the present invention may vary from low vi~co~ity thln fluids to viscous gums, depending on the value of n and the nature of the particular organic groups represented by Rl and R2 of formula (1).
The viscosity of the silanol chain stopped polydiorganosiloxanes thus varies broadly, e.g., in the range of 20 to 1,000,000 cps at 25C. Preferably it will be in the range o~ 1,000 to 200,000 cps, and especially pre~era~ly from about 2,000 to about 60,000 cps at 25C.

In preferred features of the present invention, the polymeric component comprise~ from about 30 to about 99 weight percent and more preferably from about 50 to about 90 weight percent of silanol chain stopped polydiorganosiloxane A(i).
Polymeric component A also comprises component A(ii), an effective amount of water. Preferably, ~he polym~rlc component A(ii) comprises from about 0.01 to about 0.5 weight percent water based on the weight of said silanol chain stopped polydiorgano siloxane A(i).
Further, in preferr~d embodiments, where a filler A(iii) is employed, the necessary water can be present adsorbed on the filler.
The silylating agents ~(i) of the present invention are known to those skllled in the art. The preferred silylating agents for use in the practice of the pre~ent invention are those having at least one labile or leaving monovalent or divalent group attached to silicon by silicon-nitrogen linkages and selected from silane and organopolysiloxane.
Preferred silyating agents are those having a boiling point of at least 25C, and are included wi~hin the formula (R3)~SiX~ (2) where X is an organic leaving group, pre~erably carbamato, amido, amino, ureido, or imido, R3 is selected from Cl13 monovalent or divalent hydrocarbon radicals and substituted C1l3 monovalent or divalent hydrocarbon radicals, and a has a value of 0 to 3 inclusive. These silanes include, for example, but are not limited to: -N,O-bis(trimethylsilyl)car~amate;
N,O-bis(trimethyl~ilyl)tri1uoroacetamide;
N,N-bis(trimethylsLlyl)ure~; and - N-methyl-N-dimethylsilyltrifluoroacetamide.

In the fonl~ulas of the silicon-nitrogen compound and ~he silico~.e nitrogen polymer that follow, the R" and R"' radicals may be selected from hydxogen and any monovalen~ hydrocarbon radicals including fluoroalkyl radicals. Examples of the xadicals from which the R" and R"' can be selected are, for instance, alkyl radicals such as methyl, ethyl, propyL, etc., cycloalkyl radicals such as cyclohexyl, cycloheptyl, etc., mononuclear aryl radicals such as phenyl, methylphenyl, ethylphenyl, etc., alkenyl radlcals such as vinyl, allyl, etc., fluoroalkyl radical~ such as 3,3,3-trifluoropropyl, and R"' may also be alkoxy such as methoxy, ethoxy, propoxy and butoxy.
Generally, the R" and R"' radicals may have from 1 to 12 car~on atoms and more preferably tha radicals may have from 1 to 8 carbon atoms.
In addition to the above described ilicon-nitrogen materials, th~re are al80 included in the pre~ent invention, silicon-nitrogen materials having divalent hydrocarbon radicals attached to silicon atsms through sllicon-carbon linkages. For example, also included among the ~ilicon-nitrogen materials that can be employed in the practlce of the invention, are arylenesilazanes, such as phenylene silazanes, and alkylenesilazanes such a~ methylenesilazanes. In addition, variou~ other silicon-n~trogen materials, containing divalent hydrocar~on radicals are alco contemplated including copolymers and terpolymers such as silicon-nitrogen materials containing intercondensed silox~ne unit~ and silarylenesilazane units, intercondens~d silazane units, silarylene~iloxane units, and siloxane units, etc. The silicon-nitrogen polymer~
that can ~e employed in the practlce of the present invention can include silicon-nitrogen polymers in the form of silazane/siloxane copolymers having a~ least 3 mole percent of chemically combined ~ila7.y unit~ and up to 97 mole percent of combined siloxy unit ~r~ q ?~
-lO- 60SI-1340 Accordingly, the sllazane polymers can include cyclics consi~ting of chemically combined R"' / R"
--SiI~
R"' uni~s where R" and R"' are as previously defined to provide for a ratio of 1.5 to 3.0 of the sum of the R"' and R2"N radical for silicon atoms in the silazane polymer.
The definition of a silazane polymer includes linear polymers having at least one unit of the class consisting of R"
(R"2N)~R"')2 SiN -units and R~
(~" ' )3 Si~l--units where R" and R"' are a~ previously defined to provide for a ratio of 1.5 to 3 o the ~um o~ the R"' and R2"N radicals per silicon atoms in the silazane polymer.
Further silazane polymers, which are included within the definition of the above poly~ers comprise linear polymers con~isting essentially of R"' R"
-- SiN --~

units where R" and R"' are defined to provide for a ratio of 1.5 to 3.0 of the sum of the R"' and R2"N radicals per silicon atom in the silazane polymer.
In addition, the silazane polymers include polymers ha~ing at lea~t one unit selected from the class con~isting of R"' ~ R"
(R")2N _ SiN -unit~ and '~

~ 60SI-1340 (R"'~2Si - N

units where R" and R"' are as previously defined to provide a ratio of 1.5 to 3 of the sum of the R"' and R2"N
radicals per silicon atom in the silazane polymerO
In addition the ~ilazane polymers can comprise also polymers having a sufficient amsunt of units selected from R"' R" R"'~ R" I ~
- SiN - SiN - SiN
R"' l I
where R" and R"' are as previously defined to provide for a ratio of 1.5 to 3 o~ the sum of the R" ' and R2"N
radicals per silicon atom in the silazan~ polymer.
The silazane/siloxane copolymer can also be in the form of cyclics and con~ist of chemically comblned ~2"'5iO units and R"'~ R"
- SlN -~
R""
units where R" and R"' are a~ previously defined Linear slloxane copolymers are also included where the mole p~rcent of (R"')~S~ 2 unit~ can be a~ high as 97 mole percent with the balance of the units being selec~ed from R" R"l R" R"
(R"')c S~N - (R~ iO- (R")2N~ N -R"' R"' where R" and R"~ are as previously defined to provide for a ratio of the sum o~ R~ R2"N rad~cal~ per sillcon of the siloxane copolymer from 1.5 to 3.
Other linear sila~anes that are included wLthin th~ scope of the above formula~ are ones having the formula J ~ ' 2 R"~ / R~ ' R"
( R ) 3tSiN ~ Si--N t ( Si ( R ) R ~n wh~re R" and R"' are as previously defined, n is 0 or an integer and is preferably from 0 to 20 inclusive, and d is a whole number aqual to 0 to 1 inclu~ive and where d i~ equal to 0 and n is prPferably equal to 3 to 7, in~lusive.
Illustrating the silazan2s that can be employed in the practice of the present invention within the scope of the above formulas are hexamethylcyclotrisilazane, octamethyltetrasilazane, trimethyltrlphenylcyclotri-silazane, trivinyltrimethylcyclotrisilazane, etc. Other silazanes within the scope of the above formulas are as follows:
CH H CH H CH
~ 3 1 ~ 3 ~ ~ 3 CH3 - Si - N - Si - N - Si - CH3 ~H3 CH3 CH3 CH3 C~3 CH3 ICH3 CH3 CH3- Si - N - Si - N - Si - ~H3 C~3 CH3 CH3 There can be phenyl, vinyl, 3,3,3-tri-fluoropropyl and variou~ alkyl groups on the middle Si atoms (ethyl, propyl, hutyl) C~3~ C~3 CH3 C~3 ~ CH3 N - Si - N -Si - N
C~3~ CH3 C~3 ~C~3 , , CH3~ Si - O - Si - CH, CH3~ Si O ~ Si - C~3 C~3 C~3 -Si - N
N~
- Si - N
H / x ln addition to the silazanes o~ the above formulas, there is also included polysiloxanes having terminal silylamine units or silazane units as shown by the formula R" / R"'\ R"' R"
l l l l ZN - - SlO- - SiN - 2 R~/ R"' where R" and R"' are as defined previously, Z is a me~ber ~ :
selected from R" and SiR3"' where R'! And R"' and n are a~
defined previously. The polysiloxane compounds of the above formula may be prepared by ~aking ammonia or an amine and reacting it at a temperature wi~hin the range of betwe~n about 0 to 60 C. with a halogenated polysiloxane having the formula ~ R"' \ R"' xtsio t si~
\ R~ / R"' where R"' and n are as de~lned abeve and ~ is a halogen radical such a~ chloro or bromo. If a terminal silazane radical is desired, for example, a molar amount of (R"'13SiX can be reacted along wi~h th~ halogenat~d poly~iloxane, at lea~t equi~alent ~o the mole~ of halogen radical~ contained th~rein. It will, of course, be appreciated that amines of the formula . , , .

H2NR ~l are utilized for forming the silazy chain-stopped polysiloxanes of the invention where R" is as defined above, whlle in th~ case when materials are de~ired having terminal silyl amine radicals, amlnes, including amine~ of the above for~ula, can be employed having at leas~ one hydrogen available for reactlon to produce the desired polysiloxane.
The halogen chain-stopped polyd~organosiloxanes of the above formula can be made by conventional procedures such as by the controlled hydrolysis of a diorg~nodihalo~ilane, for example, dimethyldiehloro~ilane as taught in Patnode, U.S. Pa~. No. 2, 381, 3fi 6 and Hyde U.S. Pat~ Nos. 2,629,726 and 2,902,507. Another procedure that ca~ be employed involves eguilibrating a mixture of a dlorganodlchlorosilane and a cyclic ~0 polydiorganosiloxane in the presence of a metal catalyst such a3 ferric chlorlde as shown in Sauer U.S. Pat. No.
2,421,653. Although variou~ procedures utilized in forming the above poly~iloxanes are not critical, generally it ha~ been found de~irable to maintain the halogen con ent o~ the re~ulting chain-stopped polysiloxane in the range of about 0.4 to about 35 percent, by weight, and preferably from about 5 to about percent by weight. The halogen chain-stopped poly~iloxane is preferably in the ~orm of a chlorinated chain-stopped polydimethylsiloxane.
Included among the amine~ which can be employed with the h logenated polysiloxane~ are ammonia, methyl amine, aniline, dimethyl amine, ethylphenyl amine, methylethyl amine, et~.

-15~ 60SI-1340 The proce~ for producing the re~t of the sllazane compounds and silazane polymers is well known to a worker skilled in the art.
The silicon nitrogen materials can be volatile liquids, or gu~my, resinous or crystalline sollds, depending upon such factors as ~he molecular weight and the nature and average func~ionality of their respective chemically combined units. Thsse silicon-nitrogen materials include for example, silyl amlnes, silazanes and fluid polymerY consisting e3~entially of intercondensed siloxane unit~ and silazane units terminated by trioganosiloxane units, polymers consisting e~sentially of intercondensed siloxane units with or lS without silazane units terminated by silyl amine units, etc. Typical of the methods, th~t can be employed to make the materials that can be used in the present invention include tha method shown by R.O. Sauer, et al.
J.A.C.S., Vol. 68, 1~46, p. 241-44, and in U.S. Pat. Nos.
2,462,635 - Haber, 2,885,370 ~ Grozos et al., 2,573,417, and 2,579,418 - Cheronis. Examples of the polymers containing intercondensed siloxane and silazane units, and poly~iloxane3 terminated by silyl am$ne units ~hat are operable in the present in~ention are chown in U.S.
Pa~. Nos. 2,503,919-Patnode, and 2,865,91~-Hurwitz et al.
Some of the silyl amine~ that can be employed in the practice of the invention are shown in U.S. Pat. Nos.
2,429,983-Johannson, 2,807,635-Breedervelt et al. and 2,758,127-Gold~chmidt e~ al., etc.
Accordingly, the proce3s for producing such polymers and compounds is well known.

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As an example, there is given here a process for preparing hexamethylcyclotrisilazane. This is prepared by taking dimethyldichlorosilane, adding it to a satura~ed solution of ammonia in benzene while agitating the mixture. During the subse~uent addition of the dimethyldichloro~ilane ammonia can be bubbled through the mixture while the temperature i5 maintained below 50. Additional ammonia wa~ bubbled through the mixture until no further ammonium chloride is prec~pitated. The product can be recovered by stripping off the benzene under vacuum. Utilizing such a method, there can be obtained hexamethylchlorotrisilazane as well as trisilazane. Similar methods can be employed to produce any of the above compounds for wh~ch formulas were given above.
Fluoroalkyl- ubstitu~ed silazane compounds can also be prepared by a similar method a~ disclosed in the patent application of Matsumotot Ser. No. 195~579 filed on Oct. 8, 1990.
The existence oP such silyl-nitrogen compounds and silyl nitrogen polymers a~ well a~ their me~hods of preparation is disclosed in U.S. Pat. No. 3,243,404 to which a worker skilled in the art can refer to for more information.
In addition to the foregoing silyl-nitrogen compounds and silyl-nitrog~n polymers disclosed above, there can also be utllized in the in~ant invention silyl amines of the formula H - Si - (N(R )2)~-g-h wh~re R20 i8 a radical selected from the class consisting of C(1a) monovalent hydrocarbon radicals and Cl,~) alkoxy radicals and fluoroalkyl radicals, and R~ i5 selected from hydrogen and a C(~o monovalent hydrocarbon radical, and g is a whole number that varies from 1 to 3, h i~ a ."
, ;~ ' whole number that varies from 0 ko 2 and the sum of h +
g does not ~xc~cd 3. Compounds coming within the scope of the above formula are for in tance methyl di(methylamino)silane, tris(methylamlno)sllane, methyl bis(diethylamino)silane as well as the following, tris(diethylamino)silane methylbis(dimethylamino)silane tri(ethylamino~silane ethyl di (methylamino)silane ethyl di (ethylamino)silane ethyl bis(dimethylamino)~ilane Such amines are disclosed in U.S. Pat. No.
3,243,404 and can be produced by the methods disclosed in that patent. The only difficulty with the hydride amines is that they do tend to liberate hydrogen upon standing and also they tend to impart the undesirable odor of amines to the compo~ition. However, if this is not a problem, then they can be tolerated in the in~tant composition. Preferably, the silyl-nitrogen compounds such as hexamethyldisilazane and the re~t, are utilized in a concentration of 0.5 to 10 parts by weight per 100 parts of the base organopolysiloxane polym~x.
Examples of fluorosilicone silazane compounds within the scope of the above formulas are, for instance, compounds su~h as one~ having the formulas (c~3cH2cH2(~H3)si)2NH
(CF3CH2CH2~CH3)SiNH) (CH3)3Si - N - Si - N Si(CH3)3 ~ 2 ;~!r,r~

(CF3C~2C~2(~H3)2Si)2N CH3 ~CF3CH2C~2(CH3) SiN ~

rCF3C~2CH2(~H3) SiN
L CH3 ~
Preferably, the silyating agen~s are organosilazane~ and/or cycloorganosilazane~ such as hexamethyldisilazane, 1,3-divinyl-1,1,3,3-t~tramethyldi-silazane, hexamethylcyclotxisilazane, octamethylcy~lo-tetrasilazane and mixtures of any of ~he foreyoing. Most preferred i~ hexamethyldlsilazane.
The silylating agents are employed in the present composition in amount~ ran~iny from about 0.1 to about 10, more preferably from about ~.5 to about 5 percent by weight based on the total weight of the B
component. ~09t pr~ferred is whers th~ silylating agent is pre~ent in an amount ranging from 0.1 to 1 part by weight bas~d on 100 parts by weight of silanol chain stopped polydiorganosiloxane A(i)o ~ he condensation cure cataly~t B(i$) may be any known to be useful for promoting the reaction between the silanol chain stopped diorganopolyslloxane and the crossllnking ag~nt. The con~ensation catalysts are generally selected from tin compounds, ~ircsnium compounds and titanium compounds, or mix~ures thereof, although other metal and nonm~tal catalysts are useful in the prac~ice of the present inven~ion.
Effective amounts of the condensa~ion ca~alysts which can be u3ed in the pract~ce of the present inventlon to facilitate the cure of the RTV compos tlons aret for example, 0.001 to 205 part based on the weight of 100 part3 of the silanol chain stopped polydiorgano-siloxane component. More particularly a~d by way o~
illustration, the conden~ation catalyst may be a tin compound, for example, di~utyltlndilaurate;
dibutyltindiacetate; dibutyltinmethoxide, .
. ~. . ,~.
~: . ., . , ~ .

..

-l9- 60SI-1340 dibutyltinbis(ace~ylacetona~e), carbomethoxyphenyltin-tris-suberate; tin octoate; isobutyltin triceroate;
dimethyltindibutyrate; dimethyltindineodecanoate;
triethyltintartrate; d~butyltin di~enzoa~e; dibutyltin oxide; tin oleate; tin naphthena~e; butyltintri-2-ethylhexoate; tinbutyrate; and mixtures of any of the foregoing. The preferred condensation catalysts are tin compounds and dibutyltinph~halate, dibutyltindiacetate 1~ and dibutyltindilaurate are par~icularly preferred.
Titanium compounds which can be used in the practice of ~he pr~ent invention are, for example, 1,3-dioxypropanetitanium bis(acatylacetonate); diisopropoxy-titanium bis~acetylacetonate); titanium naphthenate;
tetrabutyltitanate; tetra-2-e~-hylhexyltltanate; tetra-phenyltitanate; tetraoctadecyltitanate; ethyltriethano-aminotltanate. In addition bsta-dicarbonyltltan1um compounds as shown by Weyenberg, United 5tates Patent No.
3,334,067 can be used a~ condensation catalysts in the present invention.
Zirconium compounds, for example, zirconium octoa~e, also can be used.
Further examples of metal condensation catalysts are, for example, lead 2-ethyloctoate; iron 2-ethylh~xoate; cobalt 2-ethylhexoate; mangane~e 2-ethylhexoate; zinc 2-ethylhexoate; antimony octoate, bismuth naphthenate; zinc naph~henate; zinc stearate and mixtures of any of the foregoing.
Exampls~ of nonmetal condensation catalysts are hexylammonium acetate and benzyltrimethylammonium ace~ate and mixtures thereof.
The compositions of the presen~ invention also preferably comprise a cros~linking a~ent B(iii), e~pecially a trifunctional ("T") or tetrafunctional ("Q"3 hydroxy re~ctive silane. These are generally of the formula ~r,,~ t~,~

R~Si(oR5)5~ (4) wherein R4 is an organic radical of up to 8 carbon atoms selec~ed from hydrocarbyl, halohydrocarbyl and cyano lower alkyl and R5 is an organic radical of 1 to 30 carbon atoms selected from hydrocarbyl and halohydrocarbyl, and m ha~ a value of 0 to 3 and pr~ferably 0 to 1.
Illu~trative organotrialkoxy silanes useful as crosslinkers in th~ present invention include CH3Si(OcH3)3 CH3Si(OcH2c~3) 3 CH3Si(Oc~zcH2c~3)3 CH3C~2Si(O~3)3 CH3CH2si(OcH2cH3)3 CH2=CHzSi(OCH3)~

~ Si(ocH3) 3 C~3~H2~H2cH2c~2cH2~2cH2si(O~H3) 3 CF3cH2~i(OcH3)3 ; (CH3)Si(OCH2CH2CH2CH3) 3 NCCH2CH25i(OCH3)3 2S These organotrialkoxysilanes are ~ui~ably dascribed by Barridge in United States Patent No. 2,184,555l assigned to the same a~ignee a~ the present invention.
Illus rative of useful organotriacyloxysilane cros~linking agent~ for u~e in the pre~ent invention are tha following:
c~3si(oC()c~3)3 CH3CH2Si(Oc(O)~H3)3 CH2=C~2si(O~(o)cH3~3 ~ Si(OC(O)CH3)3 CH3Si(OC(~)(cHz)5cH3)3 i .
, .

~ Si(OC(O)(CHz)~CH3)3 CH3(CH2)6CH2si(~c(~)(cH2)4cH3)3 CF3(CH2)2Si(OC(O) (CH2)4CH3)3 NCC~2CH2Si(OC(O)(CH2)4CH3)3 CH3si(oc(o)cH(c2Hs) (CH2)CH3)3 CH35i(OC(O) ~ ) 3 These silanes are also w211 known in the art and can ~e made by techniques disclosed, for example, in Beers, United States Patent ~o. 3,382,205, assigned to the same assignee a~ the present invention.
Preferably, in the crosslinking agent, m has a value of 0 and the Rreferred silanes for use in the invention are tetra(n-propyl)silicate, tetraethyl-silicate, "partially condensed" ethylsilicate -available commercially from Union Carbide, AXZO or HULS as ES-40 or Silbond 40.
Th~ crosslinking agents B(ii) are used in effective amounts to ensure a substantially cured composition. Preferably from about 0.25 to about S parts by weight of crosslinking agent B(ii) based on 100 parts by weight of the silanol chaln stopped polydiorgano-siloxane A(i) is employed.
The compositions of the present invention may also comprise as part of polymeric compon~nt A a Piller or an extender A(iii~. Illustrative of the many fillers whlch can be employed with the compositions of the present invention are titanium dioxide, li~hophone, zinc oxide, zirconium silicate, silica aerogel, iron dioxide, diatomaceous earth, calc~um carbonat~, ~um~d silica, linear or cycllc polysiloxane treated sillca, silazane treated sillca, precipltated silica, glas3 flbers, magnesium oxide, chromic oxide, zirconium oxide, aluminum . . , :
.

~.r J.~ ~r~ r~
J ~ ,`,t ~

oxide, crushed quartz, calcined clay, a~bestos, carbon, graphite, cork, cot~on, synthetic fibers, etc. Among the most use~ul fillers are calcium carbonat2 alone, or mixed with fumed silica. Also preferred is a mixture of ground and precipitated or colloidal calcium carbona~e.
Organosilicone- or silazane-treated silica fillers, such as those described in Lucas, Unlted States Patent No.
2,938,009; Lichtenwalner, United States Patent No.
3,004,859; and Smith, United States Pstent No. 3,635,743, are also particularly suitable for use in the R~V
compositions of th~ present invention~ The fillers are generally employed in any effective amount. Preferably they are employed in amounts ranging from about 5 to about 200 parts, and more preferably, from about 10 to about 150 parts by weight per 100 parts of the silanol chain-s~opped polydiorganosiloxane component.
The cataly t ~omponent B of the compositions of the present invention can also comprise B(iv) a wide variety of adhesion promoters a~ is known to those skilled in the art. Preferred adhesion promo~ers are ~ilyl maleates, silyl fumarates, silyl succinates, silyl i~ocyanurate~ and mlxture-~ ~hereof. Generally, such adhesion promoters may be utilized anywhere up to an effective amount in the composltion which can vary somewhat from adh~slon promoter to adhesion promoter.
Too much of the adhesion promoter will not yield any further desirable results and in soma instances may detract from the physical properties of th~ cured RTV
composition. Accordingly, generally the adhesion promoter is utilized at a conc~ntration of anywhere from 0.1 to 10 parts and more preferably from 0.1 to 5 parts by weight per 100 parts by weight of the silanol chain stopped polydiorganosiloxane A(i).

, A suitable adhesion promoter is one of the following general formula:

Rt (R )3 t Si ` Z ~5) where R6 and R' are Cl 8 monovalent hydrocarbon radicals, t varies from 0 to 3 and Z is a saturated, unsaturated or aromatic hydrocarbon residue which may be fur~her functionalized by a member selected from the class consi~ting of amino, ether, epoxy, iscyanato, cyano, acryloxy and acyloxy and combinations thereof.
In one instance, the ~dhe~ion promoter is an amine adhesion promoter of ~he for~ula:

Rt R9 (R6O) ~ SL - R3 N - R10 (6) where R5 and R7 ar~ Cl9 monovalent hydrocarbon radicals, t varies from Q to 3, and R8 i~ a C2 12 divalent hydrocarbon radical, and R9 and Rl are selec ed from the clas~ consisting of hydrogen, amine radicals, and Cl~ :
hydrocarbon substituted amine radicals and Cl 8 monovalent hydrocarbon groups and mixtures thereof.
Specifically, R~ is selected fro~ alkylene and arylene substituted or unsubstituted divalent hydrocarbon radicals of 2-12 carbon atoms and more pref~rably from 2-8 carbon atom~. The xadical~ R9 a~d Rl can be hydrogen or any of the Cl~ monovalent hydrocarbon radicals dlsclosed for the R5 and R7 radicals. However, preferably, they can be selected from amine radical~ a~d substituted amine radical8, such a~ for in~ance, aminoethyl. Tt i8 po8tulated that mo~t of the s$rictly amine or nitrogen func~ionalized adh~ion promoter~ of Unit~d States Pa~ent No. 3,888,815 which are disclo~ed ln that patent can bo utLlized a~ adhe31On promoters in the , .
, ~r ~

instant case. For a full~r d~scription of such compounds, one is referred to the disclosure of the foregoing Bess~mer et al. patent, United States Patent No. 3,888,815. Such compounds can be made, for instance, as set forth in the discloqures of United States Patent Nos. 2,930,809 and 2~971,864, bo~h of which are incorporated herein by reference. Preferred compounds within the formula above are for instance, 3-(2-- 10 aminoethylamino)propyltrimethoxy silane. Other compounds are gamma-aminopropyltriethoxysilane and gamma-aminopropyltrimethoxysilane. other preferred amine adhesion promoters that can be utilized in the instant invention are as follows:
gamma-aminopropylmethyldiethoxysilane;
gamma-aminopropylmethyldim2thoxys ilane;
bis(3-(triethoxysilyl)propyl)amlne;
bis(3-(triethoxy~ilyl)propyl)ethylenediamine;
3- ( 2-aminoethylamino) -propyldimethoxy-t-butoxysilane;
methacryloxyethylaminopropyltrim~thoxysilane;
methylaminopropyltrimethoxysilane;
methylamlnopropyltriethoxysilane;
(N,N-dimethyl-3-amino)propyltrimethoxysilane;
N,N~dimethylaminophenyltriethoxy~ilane; and N,N-dimethylaminoe~hyldimethoxysilane.
Accordingly, although most silanes functionalized by amine~ were not experimen~ed with, it is envisloned that most silanes functionalized by amines should operate in the instant invention as adhesion promoters.
Another adhesion promoter that can be utilized in the instant inven~ion are ths isocyanurate adhesion promoters of the formula -.5.~

( ~120 ) _ Rl1 N ~ ~N/ (7) /~ C ~
o N o G

where G is s~lected from R1l or tR12)3 b - Si - Rl3 radicals, styryl, vinyl, allyl, chloroallyl, cyclohexenyl, R13 i8 a C2 12 divalent hydrocarbon radical selected from alkylenearylene, alkylene, cycloalkylene and halo-substituted divalent hydrocarbon radicals, and R11 and R12 are selected ~rom the same radicals a~ Rs and R~ and also cyano alkyl, and b varie~ from 0 to 3.
For more information as to such compound~, one i~ referred to the di clo~ure o~ Be~rs, United States Patent No. 4,100,129 and Berger, United States Patent No.
3,8210218 which are hereby incorporated by reference.
The most preferred of thece adhe~ion promoters are 1,3,5-tristrimethoxysilylpropylisocyanurat~ and bis-1,3-trimethoxysilylpropylisocyanurate. Again, much detail will not be given a~ ~o the preparation of such compounds. The radical R12 can be selecte~ from any divalent hydrocarbon radical sub3tituted or unsub~tituted so long as it doe~ not interfere with the adhesion promoter activitie~ of the compound. It should be noted that highly complicated compounds are not de~red as they are far more difficul to prepare and thus more expensive to obtain. Oth~r specific compounds are:
1,3,5-tristrimethoxysilyIpropyli~ocyanurate;
1,3,5-tristrimethoxysilylethyll~ocyanura~e;
: 1,3,5-trisms~hyldimethoxysilylpropylisocyanurate;
and 1,3,5 trl~methyldiethoxy~Llylypropylisocyanurate.

I . . ~ . .

.
.

Another adhesion promoter compound which may be utilized in the instant invention is, for instance, an eth~r adhe~ion promoter having the general formula:

(R )3-t Si - RaO - Rl4 - CH ~CH (8~

wherein R6 and R' and t are a~ previou~ly defined, R3 is a C212 divalent hydrocarbon radical, R~4 is a C212 divalent hydrocarbon radical and R~5 is selected from the cla~
consisting of hydrogen and a Cl 8 monovalent hydrocarbon radical. The radicaL R8 and Rl~ can be any divalent hydrocarbon radlcal~ such as alkylene radicals, arylene radicals, alkylenearylene radicals, both saturated and un~aturated a3 disclo~ed previously for the other compounds, and can be substituted or un~ubstituted with various group~ such as halogen group~, ether group~, e~ter groups, and other hydrocarbsn group~. The radical R1~ can be hydrogen or a monovalent hydrocarbon group as previously defined for ~6 and R' and i3 most pr~ferably hydrog~n. The mo~t pre~erred of the~e compounds is gamma-glycidoxy propyltrim~thoxysilane. Other specific compounds which are pre~erred as adhe~ion promoters in the in~tant invention are for instance;
gamma-glycidoxypropylmethyldimethoxysilane;
gam~a-glycidoxypropyltriethoxysilane;
gamma-glycidoxypropylmethyldiethoxysilane; and beta-glycidoxyethyltrimethoxysilane.
The~e compounds can be made by silicone producer~ as d~cribed in the literature or obtained from specialty chemical supply houses.
Another ~roup of compound~ which are u~eful a~
adhesion promoter~ within the ~cope of the present invention are epoxy functlonalized and have the formula:

(R )3 t Si R3 Q (9) where R6, R7 and t are as previously defined, Ra is a C2 l2 divalent hydrocarbon radical and Q is an epoxy func~ional radical having a saturated hydrocarbon ring appended thereto. The radical Ra can be any divalent hydrocarbon radical substitu~ed or un~ubstitu~ed, saturated or unsaturated with substituent groups being selected from monoralent hydrocarbon groups, halogen groups, ether groups, ester groups, etcO It should he understood that in all foregoing formulas of adhesion promoters in this application, the R8 can be any divalent radical of 2 to 12 carbon atoms having monovalent hydrocarbon radicals, halogen radicals, e~ter radlcals, and other radicals sub~tituent there~o and Ra rad~cals can be satura~ed or un~aturated and sub~tltuted or unsu~3tituted. Specific examples of such radicals are alkylene and arylene radicals and alkylenearylene combination radicals. A
specific adhesion promoter of this t~pe is beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Other compounds of this type are as follows:
gamma-~3,4 epoxycyclohexyl~propyltrimethoxysilane;
beta-(3,4-epoxycyclohexyl)ethyltriethoxysilane;
beta-(3~ 4-epoxycyclohexyl) ethylmethyldi-methoxysilane;
beta-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane;
gamma-(3~4-epoxycyclohexyl)propylmethyldimethoxy-silane;
beta-(3~4-epoxycyclohexyl)ethyltris(methoxye~h silane.

' ~ :' ' I ~ , , . . .
., . , ~ , -It should be noted that the Z radical in formula (5) al50 can be an unsaturated radical such as vinyl or allyl radical of 2-12 carbon atoms and can be substituted, unsubstituted, with groups such as monovalent hydrocarbon radicals, halogen groups, ester groups and ether groups. Preferably, Z is a Cz 12 olefinic hydrocarbon group such as vinyl allyl. The prefer:red compound coming within the scope of the above definition is vinyltrimethoxysilane. Other compounds coming within the scope of formula ( 5 ) above are as follows:
virlyltriethoxy~ilarl~;
allyltrimethoxysilane;
allyltriethoxysilane;
~inylmethyldiethoxysilane;
vlnyltrimethoxysilane; and vinyltris(2-methoxyethoxy)silane.
~no~her group of adhesion promoters coming within the scope o~ formula (5) above are the cyano functionalized compounds of the formula:

(R O)3~ Si - R C ~-~ (10) - 25 where R6, R7 and t are as previously defined and R3 is a C2 12 divalent hydrocarbon radical and may be any of the R8 radicals previously defined in this application; that is saturated or unsaturated, substituted or un~ubstituted.
A preferred speciflc compound with the scope of formula (10) above i~ gamma-cyanopropyltrimethoxy~ilane. Other specific compounds are as follow~:
3-(cyanoethoxy)-3-methylbutenyltrimethoxysilane;
beta-cyanoethylmethyldimethoxysilane;
beta-cyanoethyltriethoxysilane;
beta-cyanoethyltrimethoxysilane;
2-cyanoethylmethyldiethoxysilane;
3-cyanopropyltriethoxy~ilane;

-29- 60~I-1340 3-cyanopropylmethyldlmethoxysilane and anoethyltris~methoxyethoxy)silane~
Another group of compounds coming within the scope of formula (5) above and whlch may ~e utilized as adhesion promoters are the ac~yloxy functionalized compounds of the formula Rl7 o Rt7 Rl8CH =- C --C--O -- Ra _ S i ( oR6 ~ 3 ,~ ( 11 ) where R6, R7 and t are as previously defined. In formulas (S) - (10), t can vary from 0 to 3 and R3 is a C2~2 divalent hydrocarbon radical a~ previously defined.
Further, Rl6 and Rl7 are selected from the class consisting of hydrogen, Cl a monovalen~ hydrocarbon radicals, and mixtures thereof. It should be noted ~hat R16 and Rl7 can be sub~tituted or unsubstituted. A pre ~rred compound comins within the s~ope of formula (ll) above is gamma-methacryloxypropyltrimethoxysilane. Other preferred compounds of formula (11) which can be utllized in the practice of the present inventlon are: -gamma-acryloxypropyltrimethoxysilane;
gamma-acryloxypropyltriethoxysilane;
gamma-methacryloxypropyltri~thoxysilane;
ga~ma-me~hacr~loxypropyltris(methoxyethoxy)cilane;
gamma-methacryloxypropylmethyldlmethoxysilane; and beta-methacryloxyethyltrimethoxysilane.
Furthermore, mo t of the above chemicals can be obtained from specialty chemical houses such as HULS
America, Levittown PA; Union Carbide, CT; Dow-Corning, MI; and Silar Laboratorles, NY.
The composlt~ons o~ the present inv~ntion are generally prepared by flrst preparing a polymeric component A comprising (1) a silanol stopped polydiorganosiloxane; (Li) an effective amount of water;

. , ' ' ' ::

and optionally (iii) an effective amount of a filler.
Next a catalyst componen~. ~ is prepared comprising (i) an ef~ective amoun~ of a silylating agen~ having at least one labile monovalen~ or divalent group attached to silicon by silicon-nitrogen linkages and selected from silane and organopolysiloxane, (ii) an ef~ec~iYe amoun~
o a condensat$on cure catalyst, and (iii) an effective amount of a crosslinking age~t; and optionally (iv) an effective amount of an adhesion promoter.
~ h~ two components A and B are then admixed in an admixing device as is known to tho~e skilled in the art, at conditions to e~fect the curing of the polydiorganosiloxane. Preferably, the components A and B are admixed in a ratio of from about 80 to about 120 parts by weight of polymeric component A to from about 5 to ahout 20 parts by weight of cataly~t component B.
More preferred is a we~ght ratio o~ from about 90 to about 110 parts by weight A to from about 5 to about 15 parts by weight ~.
It is also contemplated that other additives such as pigment~, stabilizers, plastlcizer~ and the like can be added to the compo~itions of the present inventlon.
The novel two part room tempexature vulcanizable silicone compositions o~ the subject invention are partlcularly suitable for ga~eting, adhesive and sealing applicatlons where excellent adhesion to a variety of substrate~ i~ important. For example, the compo~itions are useful in OEM assembly and indu~tr~al caulking and seal~ng in building, fac~ories, transportation vehicl~s, and the like and w1th substrates such as ma~onry, gla~s, plastics such a~ polyearbonate, metal, wood, and the like. The compositions are also advantageous in having excellent rate~ o~ application, ~ r?~r ~2 making them readily suitable for application in automatic dispen~ing equipment under standard conditions.

DESC~IPTION OF THE PREFE~RED EMBODIMENTS

The following example~ illustrate the present invention. They ar~ not to be con~trued ~o limit the scope of the appended claims in any manner whatsoever.
E~MPLES 1 2 A 30 mm Werner Pfleiderer Twin Screw Extruder wa~ u~ed to compound an RTV base ("A" component) comprised of 30 weight percen of 5000 eps polydimethylsiloxanediol, 23.7 weight percent of 25,000 cp~ polydimethylsiloxanediol, and 47.3 weight percent of a fatty acid tr~ated preclpitated CaCO3 (BET ~pecific surface area of 16-20 m2~g, average particle size of 0.05 - 0~1 microns). Thls ba~e exhlbited a ~oeing flow of 0.50 inches, viscosity (Brook~ield RVF vi~cometer, No. 7 spindle at 2 rpm) of 590 Kcps, and specific gravity of 1.369 g/c~.
The same extruder was u~ed to compound a paste catalyst ("B" component) co~prised of 64.5 weight percent of 10,000 cps trimethylsilyl endstopped polydimethylsiloxana, 10 weight percent of octamethylcyclotetra~iloxane (D~, trea~ed fumed silica (average BET surface area = 200 m2/g), 2 weigh~ percent of "Black Masterbatch" (50 weight pQrcent carbon black in 300 cp~ dimethylvinyl terminated polydlmethylsiloxane), 15 weight percent of 3-aminopropyltriethoxysilane, 2.5 weigh~ percent of 1,3,5-tris(3-trimethy~ilylpropyl)-isocyanurate, 5 weight percent tetra(n-propyl)silicate, and 1 weight percent "solubilized" dlbutyltin oxide.

. ~ , .

The ~A~ and ~B~ components are combined and mixed (via a 5emco Catalyzer) at a weight ratio of 100 part~ by weight base to ~ par~s by weight catalyst. This 5 RTV is deqignated A* in ~able 1.
A second RTV, Example 1, was prepared from 100 parts by weight of the same base "A" component as described above and catlayzed with 8 parts by weight of the same paste ca~alyst "B" as described above to which 1.0 weight percent of hexamethyldisilazane ( D Z) had been added.
A third RTY, Example 2, was prepared from 100 parts by weight of the same base "A" componen~ as described above and catalyzed wi h 8 parts by weight of the same paste catalyst "B" to which 2.0 weight percent of HMD~ and 0.3 weight percent "solubilized" dibutyltin oxide had been added.
~ he R~Y composition is then applied to a polycarbonate substrate from the air actuat2d Semco tube via a 1/8 inch orifice.
The cure and physical properties of the three RTVs is set forth below in Ta~le 1.

1 0 ~ ~` U'i ~D ~ O~ O Ll'~ O I O o O ~ ~ O ~ ~ U~ 'i O I O O
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r~ r~

As can b~ seen from Table 1 above, the addition of HMD2 to the sealant reduces the time required to develop adhesion to polycarbona~e. After 24 hours, the tensile strength of a polycarbonate lap shear specimen sealed with the R~V of Example 1, containing 0.07 weight percent of HMDZ, i~ approximately 43% greater than an identical example sealed wlth the sealant of Example A*
which does not contain ~he HMDZ. Furthermore, ~he sealant of Example 2 displays a full 100% cohesive failure to polycarbonate af~er 24 hours.
It is importan~ to note that the ultimate polycarbonate adhesive tensile strength of all 3 RTVs (7 day cuxe) is nearly identical. In all cases, 1 day after the R~Vs were prepared the in~erior of a 1.5 inch diameter cylinder of R~V (2 inches from the end) were completely cured.
No "crazing" of polycarbona~e or loss of tensile value wa ob~erved for polycarbonate lap shears sealed with the RTV sealant of Example 2 and sub~ect~d to arcelerated heat aglng (7 day cure and 7 days at 100C).

XAMP~ES 3-10 A 30 mm Werner Pfleiderer Twin Screw Extruder wa~ used to compound an RTV ba~e ("A" component) comprised of 50 weigh~ percent of a 10,000 cps blend of an ~ 3,000 cps polydlmethylsiloxanediol and an ~ 30,000 cps polydimethyl~iloxanediol, 25 weigh~ percent of a rosin acid coated precip~tated CaCo3 (BET specfic surface area of 14-18 m2/g and average particle size of 0.05-0.1 micron) and 25 weight percent of a s~earic acid coated ground Ca~o3 (~pecific surface area of 6 m2/g and mean particle size of z 2 mlcrons).

r;; r ~

Elght liquid catalyst solution~ ("B" component) were prepared by combining the concentrations of 10,000 cps trimethylsilyl endstopped polydlmethylsiloxane, 3-aminopropyltriethoxysilane, tetra(n-propyl)silicate, ~olubiliz~d dibutyltinoxide and hexamethyldisilazane as set forth in Table 2 below.
Twenty four RTVs were prepared. Each of ~hese were comprised of 100 parts by weigh~ of the ba~e "A"
component de~cribed above and 8 parts by weight of liquid cataly~t aged for either 2 day~ at ambient conditions (RTVs 3A-lOA, Seri~ A), 7 days at ambient conditions plus 7 days at 70C (RTVs 3B-lOB, Series B), or 14 days a~ 70C (~TVs 3C-lOC, Series Cl. The resul~s tabulated in Table 2 demonstra e that additlon of HMDZ to the liquid catalyst causes no furkher deleterious impact on shelf life, a~ mea~ured by cure rat~ before and after accelerated aging, than th2 "control" catalyst formula~ed without ~MDZ.
rhe Shore A values displayed in Table 2 were obtained for RTVs which were cataly~ed, cured and stored in relatively imperm~able polypropylene Semco tubes prior to measurement. In this configuration, cure by-products and volatile components could not escape from the R~V, thu~ si~ulating the "worst ca~e scenario" for an adhesive application. A cxo~-section, ~ ~" height x l~" diameter cylinders of cured RTV silicone sliced and remove~ from the center o~ the Semco tube~ was u~ad for the hardness measurement. The nearly equivalent values obtainded for RTVs containing equal 3-aminopropyltrlmethoxysilane concen~rations regardle~ of HMDZ level, (RTV 3A vs. 4A, SA or 6A and RTVs 7A vs. 8A, 9A or lOA) demonstra~es that the silazane doe~ not effectlvely compete with silanol polymer to inhibit cure in deep section~ or confined geometrie~.

, ' .

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The above patents, patent applicatlons and tes~ methods are hereby incorpora~ed by reference.
Many variations of the pres~nt invention will suggest themselves to those skilled in this art in light of the above detailed de~cription. All such obvious modifications are within the full intended scope of the appended claim~.

.

Claims (30)

1. A self bonding, two component, room temperature vulcanizing composition having improved adhesion to substrates comprising:
A. a polymeric component comprising:
(i) a silanol chain stopped polydiorganosiloxane; and (ii) an effective amount of water; and B. a catalyst component comprising:
(i) an effective amount of a silylating agent having at least one labile monovalent or divalent group attached to silicon by silicon-nitrogen linkages and which silylating agent is selected from the group consisting of silane and organopolysiloxane;
(ii) an effective amount of a condensation cure catalyst;
and (iii) an effective amount of a crosslinking agent.

2. A composition as defined in Claim 1 wherein said silanol terminated polydiorganosiloxane A(i) comprises a silanol terminated dimethylpolysiloxane.

3. A composition as defined in Claim 1 wherein said silylating agent B(i) is selected from the group consisting of organosilazanes and cycloorganosilazanes.

4. A composition as defined in Claim 3 wherein said silylating agent B(i) is selected from the group consisting of hexamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, octamethylcyclo-tetrasilazane, hexamethylcyclotrisilazane and mixtures of any of the foregoing.

5. A composition as defined in Claim 4 wherein said silylating agent B(i) comprises hexamethyldisilazane.

6. A composition as defined in Claim 1 wherein said silylating agent B(i) has at least one labile monovalent group.

7. A composition as defined in Claim 1 wherein said silylating agent B(i) has at least one labile divalent group.

8. A composition as defined in Claim 1 wherein said silylating agent B(i) is selected from those of the formula (R3)aSiX4-a where X is an organic leaving group selected from the group consisting of carbamato, amido, amino, ureido and imido, R3 is selected from the group consisting of C1-13 monovalent or divalent hydrocarbon radicals and subustituted C1-13 monovalent or divalent hydrocarbon radicals, and a has a value of 0 to 3 inclusive.

9. A composition as defined in Claim 10 wherein said silylating agent is selected from the group consisting of N,O-bis(trimethylsilyl) carbamate, N,O-bis(trimethylsilyl)trifluoroacetamide, N,N-bis(trimethylsilyl)urea, and N-methyl-N-dimethylsilyltrifluoroacetamide.

10. A composition as defined in Claim 1 wherein said silylating agent comprises a silazane polymer having a sufficient amount of units selected from where R" and R"' are independently selected from hydrogent and monovalent hydrocarbun radicals to provide for a ratio of l.5 to 3 of the sum of the R"'and R2"N
radicals per silicon atom in the silazane polymer.

11. A composition as defined in Claim 1 wherein said silylating agent comprises a linear siloxane copolymer having a mole percent of (R"')cSiO(4-c)/2 units can be as high as 97 mole percent with the balance of the units being selected from where R" and R"' are independently selected from hydrogen and monovalent hydrocarbon radicals to provide for a ratio of the sum of R"' + R2"N radicals per silicon of the siloxane copolymer from 1.5 to 3.

12. A composition as defined in Claim 1 wherein said silylating agent comprises a polysiloxane having terminal silylamine units or silazane units as shown by the formula where R" and R"' are independently selected from hydrogen and monovalent hydrocarbon radicals, Z is a member selected from R" and SiR3"' where R" and R"' and n is from 0 to 3 inclusive.

13. A composition as deiined in Claim 1 wherein said silyating agent B(i) is present in an amount ranging from about 0.1 to about 10 parts by weight based on 100 parts by weight of said silanol chain stopped polydiorgano~iloxane A(i).

14. A composition as defined in Claim 1 wherein said condensation cure catalyst B(ii) comprises a tin compound.

15. A composition as defined in Claim 1 wherein said condensation cure catalyst B(ii) comprises a titanium compound.

16. A composition as defined in Claim 1 wherein said cure condensation catalyst B(ii) comprises a nonmetal cure condensation catalyst selected from the group consisting of hexylammonium acetate, benzyltrimethylammonium acetate and mixtures thereof.

17. A composition as defined in Claim 1 wherein said crosslinking agent B(iii) comprises a trifunctional or tetrafunctional hydroxy reactive silane.

18. A composition as defined in Claim 1 wherein said crosslinking agent B(iii) is present in an amount ranging from about 0.25 to about 5 parts by weight based on 100 parts by weight of said silanol chain stopped polydiorganosiloxane A(i).

19. A composition as defined in Claim 1 wherein said resin component A further comprises (iii) an effective amount of a filler.

20. A composition as defined in Claim 19 wherein said component A (ii) water is present adsorbed on said component A (iii) filler.

21. A composition as defined in Claim 1 wherein said catalyst component B further comprises (iv) an effective amount of an adhesion promoter.

22. A composition as defined in Claim 21 wherein said adhesion promoter B(iv) is present in an amount ranging from about 0.01 to about 10 parts by weight based on 100 parts by weight of said silanol or polyalkoxy chain stopped polydiorganosiloxane A(i).

23. A method for forming a two component, self bonding, room temperature vu1canizing composition having improved adhesion to substrates comprising:
A. preparing 2 polymeric component comprising (i) a silanol chain stopped polydiorganosiloxane; and (ii) an effective amount of water; and B. preparing a catalyst component comprising (i) an effective amount of a silylating agent having at least one labile monovalent or divalent group attached to sillcon by silicon-nitrogen linkages and which silylating agent is selected from the group consisting of silane and organopolysiloxane;
(ii) an effective curing amount of a condensation cure catalyst; and liii) an effective amount of a crosslinking agent;
C. comblning and mixing A. and B. to cuxe the polydiorganosiloxane.

24. A two component, self bonding, room temperature vulcanizing composition having improved adhesion to substrate prepared by the method as defined in Claim 23.

25. An adhesive composition comprising a composition as deflned in Claim 1.

26. An adhesive composition comprising a composition as defined in Claim 24.

27. An adhesive composition as defined in Claim 25 which is an adhesive, a caulk or a sealant.

28. An adhesive composition as defined in Claim 26 which is an adhesive, a caulk or a sealant.

29. An article of manufacture comprising a polycarbonate substrate having a surface laminate as defined in Claim 27.

30. The invention as defined in any of the preceding claims including any further features of novelty disclosed.