Organosilicon compounds as additives for curable organopolysiloxane compositions

Organosilicon compounds having at least one hydrocarbon radical linked to at least 75 percent of the silicon atoms via an oxygen atom in which the hydrocarbon radical has at least one hydroxyl group and may be linked again to the same silicon atom or to another silicon atom via an oxygen atom are added to room temperature curable organopolysiloxane compositions to form compositions which are resistant to flow on vertical surfaces. When these compositions are exposed to atmospheric moisture at room temperature, they form elastomers having decreased Shore hardness and modulus on the surface in contact with the substrate as compared to the surface exposed to atmospheric moisture.

This invention relates to improved organopolysiloxane compositions, 
particularly to organopolysiloxane compositions which are stable in the 
absence of atmospheric moisture, but when exposed to atmospheric moisture 
cure at room temperature to form elastomers having improved properties. 
Organopolysiloxane compositions which are stable in the absence of moisture 
but cure to elastomeric solids when exposed to atmospheric moisture are 
well known in the art. For example, French Pat. No. 2,080,523 discloses an 
organopolysiloxane composition containing diorganopolysiloxanes having 
condensable terminal groups and cross-linking agents containing at least 
three amino groups and/or acylated amino groups and/or oximo groups. 
Compared to other compositions, containing for example acyloxy groups 
instead of amino and/or acylated amino groups and/or oximo groups, these 
compositions can be cured in the presence of atmospheric moisture without 
forming corrosive compounds. Likewise, organopolysiloxane compositions 
containing diorganopolysiloxanes having acyloxy or amino groups in each of 
the terminal units and aluminum alkoxy compounds such as described in 
French Pat. No. 1,537,643 can also be cured in the presence of atmospheric 
moisture without forming corrosive compounds. In contrast to the 
organopolysiloxanes which contain the additives of this invention, the 
organopolysiloxane compositions known heretofore which may also be 
resistant to flow and which consist of organopolysiloxanes having 
condensible groups and, for example, organosilicon cross-linking agents 
which have at least three amino groups and/or acylated amino groups and/or 
oxime groups are not stable towards hydrolysis. 
Furthermore, the organopolysiloxane compositions known heretofore which can 
be stored in the absence of atmospheric moisture and cure in the presence 
of atmospheric moisture to form elastomers, have a Shore hardness, modulus 
and ratio of elasticity to plasticity which remains the same throughout 
all the cross section between the surfaces which are in contact with the 
applied substrate and the atmosphere. In many applications however, 
particularly in the sealing of joints or fissures between moving parts 
and/or parts whose dimensions vary under changing temperature conditions 
or when it is desired to coat surfaces with slits whose dimensions change 
with the temperature or when fissures do in time develop subsequent to 
coating, it is advantageous to employ elastomers whose Shore hardness and 
modulus decreases at the substrate surface as long as the elastomers 
remain in contact with the surfaces on which they have been applied. 
Elastomers having decreasing Shore hardness and modulus are especially 
advantageous because these elastomers exhibit increased plasticity when 
subjected to dynamic stress. For example, when these elastomers are used 
for sealing gaps, the increased values of plasticity within the elastomers 
result in a smaller tensile stress exerted on the joint sides when the 
gaps widen, whereas the surfaces of the elastomers which are directly 
exposed to the atmosphere are protected from mechanical damage due to 
their high elasticity. When such elastomers are used as coatings, they can 
be torn near the surface on which they are applied without any adverse 
results or they can detach from their base in a sliding movement without 
the entire cross section of the coating being torn throughout the 
coating's thickness in the event that fissures which existed prior to 
application of the coating or which have formed in the substrate 
subsequent to coating should widen and become longer. Thus, the 
compositions of this invention are not only highly resistant to flow, but 
also produce elastomers whose Shore hardness, modulus and ratio of 
elasticity to plasticity decreases when subjected to dynamic stresses 
while the elastomers are in contact with the substrates on which they have 
been applied. These compositions thus provide certain advantages which are 
not available in previously known organopolysiloxane compositions. 
Therefore, it is an object of this invention to provide organopolysiloxane 
compositions which are resistant to flow when applied to vertical 
surfaces. Another object of this invention is to provide 
organopolysiloxane compositions which are stable in the absence of 
moisture, but cure to an elastomeric solid when exposed to atmospheric 
moisture. Another object of this invention is to provide 
organopolysiloxane compositions which upon "cross-linking" or 
"vulcanization" do not release corrosive compounds. Still another object 
of this invention is to provide elastomers which are resistant to 
hydrolysis. A further object of this invention is to provide elastomers 
whose Shore hardness and modulus are lower on the surface of the substrate 
on which they are applied than on the surface exposed to atmospheric 
moisture.

The foregoing objects and others which will become apparent from the 
following description are accomplished in accordance with this invention, 
generally speaking, by providing organosilicon compounds which can be 
added to room temperature curable organopolysiloxane compositions to form 
elastomeric solids. In the organosilicon compounds, which are employed as 
additives in curable organopolysiloxane compositions, at least 75 percent 
of the silicon atoms are linked via an oxygen atom to a hydrocarbon 
radical containing one or two hydroxyl groups and/or the hydrocarbon 
radical may be linked again via an oxygen atom to the same silicon atom or 
to a different silicon atom. The organosilicon compounds or additives are 
added to organopolysiloxane compositions containing diorganopolysiloxanes 
having condensable terminal groups and cross-linking agents having at 
least 3 amino groups and/or acylated amino groups which are linked to the 
silicon atom via a nitrogen atom and/or oximo groups which are linked to a 
silicon atom via an oxygen atom per molecule. 
In the silicon compounds, at least 75 percent of the silicon atoms are 
linked via an oxygen atom to a hydrocarbon radical containing one or two 
hydroxyl groups and/or the hydrocarbon radical may be further linked via 
an oxygen atom to the same and/or different silicon atom. Moreover, it is 
preferred that the lowest possible number of hydrocarbon radicals be 
linked a second time to the same and/or at least one other silicon atom so 
that each of the hydrocarbon radicals which are not linked to a silicon 
atom via oxygen contains one or two hydroxyl groups. The silicon valences 
which are not linked to a hydrocarbon radical which is substituted with at 
least one hydroxyl group, are preferably all saturated with monovalent 
hydrocarbon radicals or substituted monovalent hydrocarbon radicals having 
from 1 to 18 carbon atoms. These monovalent hydrocarbon radicals or 
substituted monovalent hydrocarbon radicals are linked to the silicon atom 
via SiC-linkages. 
Examples of hydrocarbon radicals with which the silicon valences in the 
organosilicon compounds can be saturated through SiC-bonding are alkyl 
radicals such as the methyl, ethyl, n-propyl and isopropyl radical as well 
as the octadecyl radicals; alkenyl radicals such as the vinyl and allyl 
radicals; alkinyl radicals; cycloaliphatic hydrocarbon radicals such as 
the cyclopentyl and the cyclohexyl radicals as well as methylcyclohexyl 
and cyclohexenyl radicals; aryl radicals such as the phenyl radical and 
xenyl radical; aralkyl radicals such as the benzyl, beta-phenylethyl and 
the beta-phenylpropyl radical, as well as alkaryl radicals such as the 
tolyl radical. 
The substituted hydrocarbon radicals with which the silicon valences in the 
silicon compounds can be saturated through an SiC-bond are haloaryl 
radicals such as chlorophenyl and bromophenyl radicals; perfluoralkylethyl 
radicals such as the perfluoromethylethyl radical and cyanoalkyl radicals 
such as the beta-cyanoethyl radical. 
It is preferred that 1, 2 or 3 SiC-linked hydrocarbon radicals be present 
per Si atom in the organosilicon compounds which are employed as additives 
in this invention. 
The hydrocarbon radicals which are linked to silicon via oxygen and which 
is substituted with one or more hydroxyl groups ar preferably those which 
correspond to the general formula 
EQU --OCR'H [C(OH).sub.b R'.sub.2-b ].sub.c CHR'OH 
wherein R', which may be the same or different, represents hydrogen, 
monovalent hydrocarbon radicals or substituted monovalent hydrocarbon 
radicals having from 1 to 18 carbon atoms, b is equal to 0 or 1 and c is a 
number of from 0 to 6, with the provision that in no more than one of the 
units C(OH).sub.b R'.sub.2-b can b have a value of 1. 
The monovalent and substituted monovalent hydrocarbon radicals represented 
by R' are the same as those described above for SiC-linked monovalent 
substituted and unsubstituted hydrocarbon radicals except for the vinyl 
radical. If in the above formula one unit of the formula C(OH).sub.b 
R'.sub.2-b is present, i.e., where b equals 1, then R' may be the same as 
described above for SiC-linked monovalent substituted or unsubstituted 
hydrocarbon radicals except for the vinyl radical. Futhermore, it is 
preferred that c be a number with a value of from 0 to 4. 
The hydrocarbon radicals which are linked to a silicon atom via oxygen and 
which may be linked again to the same or to at least another silicon atom 
via an oxygen atom are preferably those corresponding to the above formula 
in which at least one hydrogen atom of a hydroxyl group is substituted 
with a silicon atom such as illustrated by the following formula 
EQU --SiOCH.sub.2 CH(OH)CH.sub.2 OSi-- 
In accordance with this invention, the organosilicon additives may consist 
of mixtures of various organosilicon compounds in which at least 75 
percent of the silicon atoms are linked via an oxygen atom to at least one 
hydrocarbon radical which is substituted with one or two hydroxyl groups 
and may be linked to the same silicon atom or to another silicon atom via 
an oxygen atom. 
These organosilicon compounds having at least 75 percent of the silicon 
atoms linked via an oxygen atom to at least one hydrocarbon radical which 
is substituted with one or more hydroxyl groups and may be linked via an 
oxygen atom to the same silicon atom or to another silicon atom can be 
prepared by any process known in the art for preparing such compounds. 
It is preferred that the organosilicon compounds which are used as 
additives in this invention be prepared by reacting bivalent or trivalent 
alcohols especially those corresponding to the general formula 
EQU HOCR'H [C(OH).sub.b R'.sub.2-b ].sub.c CHR'OH 
where R', b and c are the same as above with silanes corresponding to the 
general formula 
EQU R.sub.a SiX.sub.4-a 
wherein R is the same or different and represent substituted and 
unsubstituted hydrocarbon radicals and X represents halogen such as 
chlorine, bromine or iodine, preferably chlorine, and a represents 0, 1, 2 
or 3, preferably 1, 2 or 3. 
Examples of suitable bivalent and trivalent alcohols are ethylene glycol, 
1, 2-propylene glycol, trimethylene glycol, 1,2-butylene glycol, 
1,3-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol, pinacon, 
neopentyldiol, glycerine, trimethylolpropane, 2-methyl-1,4-butanediol, 
2,5-dimethyl-3-hexene-2,5-diol and 1,6-hexanediol. 
Examples of suitable silanes which correspond to the general formula 
R.sub.a SiX.sub.4-a are methyltrichlorosilane, dimethyldichlorosilane, 
trimethylchlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, 
n-octadecyltrichlorosilane, phenylmethyldichlorosilane, 
bromophenyltrichlorosilane, cyclohexyltrichlorosilane, 
n-propyltrichlorosilane, diphenyldichlorosilane and silicon tetrachloride, 
as well as bromophenyltribromosilane and cyclohexyltriiodosilane. 
The reaction of bivalent or trivalent alcohols with halosilanes is 
generally known and described, for example, in U.S. Pat. No. 2,906,768 to 
Haluska. 
The organosilicon compounds which are used as additives in accordance with 
this invention may also be prepared by other processes known in the art. 
For example, the bivalent or trivalent alcohols can be reacted with 
silanes corresponding to the general formula R.sub.a Si(OR.sup.1).sub.4-a, 
where R and a are the same as above and R.sup.1 represents an alkyl 
radical having from 1 to 6 carbon atoms or an aryl radical. Also, the 
bivalent or trivalent alcohols can be reacted with silanes corresponding 
to the general formulae R.sub.a Si(OOCR.sup.1).sub.4-a, R.sub.a 
SiH.sub.4-a, R.sub.a Si(NR.sub.2.sup.3).sub.4-a, where R, R.sup.1 and a 
are the same as above and R.sup.3 is the same as R or hydrogen. In 
addition, these organosilicon compounds can be prepared by reacting 
bivalent or trivalent alcohols with silanols of the general formula 
R.sub.a Si(OH).sub.4-a, in which R and a are the same as above. The 
bivalent or trivalent alcohols can be reacted with other silylating agents 
such as, for example, N,N-bis-(trimethylsilyl)formamide or with a mixture 
of hexamethyldisilazane and trimethylchlorosilane to form the 
organosilicon compounds. 
In all the processes described above for preparing the organosilicon 
compounds, generally from about 1.0 to 1.13 mols of bivalent or trivalent 
alcohols are used for each equivalent of reactive group or for each 
reactive atom on the silane or silylating agent. 
The reaction products obtained from the reaction of the bivalent or 
trivalent alcohols with halosilanes are illustrated by the general 
formulae 
##STR1## 
and the like. 
Since the exact nature of the reaction products formed as a result of the 
reaction of the bivalent or trivalent alcohols with the haolsilanes is not 
known with certainty, the present invention is not intended to be limited 
to any particular formula. Analytical data indicates that at least during 
the reaction of bivalent or trivalent alcohols with halogen silanes, the 
silicon valences of the resulting products which are not completely 
saturated via oxygen with hydrocarbon radicals which are substituted with 
one or two hydroxyl groups and/or are linked a second time via an oxygen 
atom to the same or different silicon atom, are satisfied with SiC-linked 
hydrocarbon radicals. In the products thus obtained at least 75 percent of 
the silicon atoms are linked via oxygen to at least one hydrocarbon 
radical containing one or two hydroxyl groups or the hydrocarbon radical 
may be further linked via an oxygen atom to the same or a different 
silicon atom. 
The organosilicon compounds which are used as additives in this invention 
may be further described as being products obtained from the reaction of 
one mol of n-propyltrichlorosilane and 3.5 mols of propylene glycol; 1 mol 
of diphenyldichlorosilane and 2.2 mols of ethylene glycol; 1 mol of 
trimethylchlorosilane and 1.1 mols of glycerine; 1 mol of 
trimethylchlorosilane and 1.1 mols of 1,4-butandiol; 1 mol 
trimethylchlorosilane and 1.1 mols 1,2-propylene glycol. 
It is preferred that the organosilicon compounds of this invention be 
employed in amounts of from 0.05 to 5 percent by weight and more 
preferably in amounts of from 0.2 to 2 percent by weight based on the 
total weight of the composition, i.e., the diorganopolysiloxanes, 
cross-linking agents and the organosilicon compounds which are capable of 
cross-linking to form elastomers. The term "organosilicon compounds" or 
organosilicon additives as used herein refers to the total amount of 
reactants employed in the preparation of the organosilicon compounds used 
as additives in this invention, i.e., the bivalent or trivalent alcohols 
and the halosilanes. Thus, it is not essential that the organosilicon 
compounds used as additives in this invention be separated from the other 
products obtained as a result of the reaction between the bivalent or 
trivalent alcohols and the halosilanes. 
It is also possible within the scope of this invention to use the same 
diorganopolysiloxanes containing terminal condensable groups as have been 
used heretofore in the preparation of organopolysiloxane compositions 
which can be stored in the absence of moisture but when exposed to 
moisture cross-link to form elastomers. These organopolysiloxane 
compositions also contain cross-linking agents having a total of at least 
3 amino groups or acylated amino groups which are linked to a silicon atom 
via nitrogen atom and/or oxime groups which are linked to a silicon atom 
via an oxygen atom for each molecule. The diorganopolysiloxanes having 
condensible terminal groups which are mostly used in the preparation of 
such compositions and which are preferred within the scope of this 
invention correspond to the following general formula 
EQU HO [SiY.sub.2 O].sub.x SiY.sub.2 OH 
wherein Y, which is the same or different, represent monovalent hydrocarbon 
radicals or substituted monovalent hydrocarbon radicals and/or polymeric 
hydrocarbon radicals and x represents a whole number having a value of at 
least 10. 
These siloxane chains may have other siloxane units in addition to the 
diorganosiloxane units (SiY.sub.2 O) along the siloxane chain. These units 
are generally present as impurities and usually correspond to the formulae 
YSiO.sub.3/2, Y.sub.3 SiO.sub.1/2 and SiO.sub.4/2, where Y is the same as 
above. The amount of such other siloxane units should not, however, exceed 
more than about 10 percent and preferably the amount should not exceed 
about 1 mol percent. Other siloxane units such as those corresponding to 
the general formula 
EQU --OSiY.sub.2 R"SiY.sub.2 O--, 
where Y is the same as above and R" represents a divalent hydrocarbon 
radical such as, for example, a phenylene radical can be present in 
substantial amounts. If desired, the hydroxyl groups in the above 
indicated formula can be partially or entirely substituted with 
condensable groups other than Si-linked hydroxyl groups. Examples of such 
other condensable groups are amino groups which are linked to a silicon 
atom via a nitrogen atom, oxime groups which are linked to silicon atom 
via an oxygen atom, alkoxy groups having from 1 to 5 carbon atoms and 
alkoxyalkylenoxy groups having from 1 to 5 carbon atoms such as the 
radical of the formula 
EQU CH.sub.3 OCH.sub.2 CH.sub.2 O--. 
the above indicated examples of Si-linked hydrocarbon radicals and 
substituted SiC-linked hydrocarbon radicals represented by R are equally 
applicable for the hydrocarbon radicals represented by Y and unsubstituted 
polymeric hydrocarbon radicals including the so-called "modified" 
hydrocarbon radicals such as those derived from a graft polymerization of 
polymerizable compounds with diorganopolysiloxanes corresponding to the 
general formula 
EQU HO [SiR.sub.2 O].sub.x SiR.sub.2 OH 
where R and x are the same as above. Examples of polymerizable compounds 
are vinyl acetate, acrylic and/or methacrylic acids, acrylic and/or 
methacrylic acid esters and/or methacrylonitrile. 
Although it is preferred that at least 50 percent of the Y radicals be 
methyl radicals, they may also be phenyl and/or vinyl radicals. 
The diorganopolysiloxanes having condensable terminal groups can be either 
homo or copolymers as well as mixtures of various diorganopolysiloxanes. 
The viscosity of the diorganopolysiloxanes having condensable terminal 
groups should be between 100 and 500,000 cSt at 25.degree. C. 
It is possible to use organosilicon cross-linking agents which have been 
employed heretofore to form organopolysiloxanes which are stable in the 
absence of moisture but are curable to elastomeric solids when exposed to 
atmospheric moisture. These silicon cross-linking agents have at least 3 
amino groups and/or acylated amino groups and/or oximo groups per 
molecule. 
Organosilicon cross-linking agents which have at least 3 amino groups that 
are linked to a silicon atom via a nitrogen atom per molecule are 
preferred. Examples of such preferred compounds and silanes corresponding 
to the general formula 
EQU R.sub.b Si(NH.sub.m R.sub.2--m.sup.3).sub.4--b' 
where R, R.sup.3 and b are the same as above and m is 0, 1 or 2 or 
oligomers resulting from the partial hydrolysis of above aminosilanes. 
Except for the vinyl radical, the previously indicated examples of 
SiC-linked hydrocarbon radicals are equally applicable for the hydrocarbon 
radicals represented by R.sup.3. Additional examples of hydrocarbon 
radicals represented by R.sup.3 are the n-butyl, sec.-butyl and the 
tert.-butyl radicals. The preferred radicals are sec.-butyl and the 
cyclohexyl radicals. 
Examples of organosilicon cross-linking agents which contain at least 3 
oxime groups per molecule which are linked to a silicon atom via an oxygen 
atom are silanes corresponding to the general formula R.sub.b 
Si(ON.dbd.X).sub.4-b, where R and b are the same as above and X is an RR'C 
group where R and R' are the same as above or an R.sup.2 C group where 
R.sup.2 represents a bivalent or substituted bivalent hydrocarbon radical 
or partial hydrolysates thereof. 
Examples of organosilicon cross-linking agents which have a total of at 
least 3 groups per molecule consisting of amino and oxime groups are 
silanes corresponding to the general formula 
EQU R.sub.b Si(ON.dbd.X).sub.d (NH.sub.m R.sub.2-m.sup.3).sub.4-b-d, 
where R, R.sup.3 and b are the same as above and d is a number of at least 
0.5 and not more than 2.9. 
Examples of suitable organosilicon cross-linking agents having a total of 
at least 3 amino groups and/or oximo groups per molecule are 
methyltris-(n-butylamino)-silane, methyltris-(sec.-butylamino)-silane, 
methyltris-(cyclohexyl-amino)-silane, 
methyltris-(methylethylketoximo)-silane, 
methylbis-)methylethylketoximo)-cyclohexylaminosilane, methyltris 
(acetonoximo)-silane, a mixture consisting of one part by weight 
methyltris-(cyclohexylamino)-silane and two parts by weight of 
methyltris-(acetonoximo)-silane, as well as a mixture consisting of 2 
parts by weight of methyltris-(cyclohexylamino)-silane and 3 parts by 
weight of methyl(methylethylketoximo)-silane. 
An example of an organosilicon cross-linking agent having a total of at 
least 3 acylated amino groups per molecule linked to a silicon atom via a 
nitrogen atom is methyltris-(benzoylmethylamino)-silane. 
Organosilicon cross-linking agents which have for each molecule at least 3 
amino groups and/or acylated amino groups linked to a silicon atom via a 
nitrogen atom and/or 3 oximo groups linked to a silicon atom via an oxygen 
atom are preferably employed in amounts such that at least 1 mol of said 
organosilicon cross-linking agent is present for each gram equivalent of 
the terminal condensable groups present on the diorganopolysiloxanes. 
Generally from 0.2 to 15 percent by weight and more preferably from 1 to 8 
percent by weight based on the total weight of the composition are 
employed. 
Materials other than the diorganopolysiloxanes having terminal condensable 
groups, the organosilicon cross-linking agents which have at least 3 amino 
groups and/or acylated amino groups and/or oximo groups linked to a 
silicon per molecule and the organosilicon additives may be incorporated 
in the organopolysiloxane compositions of this invention. 
Suitable examples of materials which may be incorporated in these 
compositions are reinforcing as well as non-reinforcing fillers, pigments, 
soluble dyes, organopolysiloxane resins, organic resins, as well as 
polyvinyl chloride powders. Other materials which may be added to these 
compositions are those that tend to improve the adhesion of the finished 
elastomers to the substrates on which they are applied such as those 
corresponding to the formula 
EQU CH.sub.3 Si [O(CH.sub.2).sub.2 NH.sub.2 ].sub.2 (CH.sub.2).sub.3 
O(CH.sub.2).sub.2 NH.sub.2. 
materials which enhance the elastomers' electrical properties such as 
conductive carbon black, corrosion inhibitors, oxidation inhibitors, heat 
stabilizers, flame repellents, light protective agents, condensation 
catalysts such as 3-ethoxypropylamino-1, and softeners such as 
dimethylpolysiloxanes which are end-blocked with trimethylsiloxy groups 
and which are liquid at room temperature may also be incorporated in the 
organopolysiloxane compositions of this invention. 
When some of the SiC-linked radicals on the diorganopolysiloxanes are 
alkenyl radicals such as vinyl radicals, it may be advantageous to employ 
organic peroxides in the organopolysiloxane compositions. These may be 
employed in amounts of from 0.01 to 5 percent by weight based on the 
weight of the diorganopolysiloxanes. 
Examples of suitable reinforcing fillers, i.e., fillers having a surface 
area of at least 50 m.sup.2 /g are pyrogenically produced silicon dioxide 
(fume silica), silicic acid hydrogels that have been dehydrated while 
maintaining their structure, as well as pyrogenically produced aluminum 
oxide and titanium dioxide. It is preferred that such fillers be used in 
an amount of from 1 to 15 percent by weight based on the total weight of 
all the organosilicon compounds, i.e., the organosilicon compound employed 
as the additive and the organopolysiloxanes, present in the composition. 
Examples of non-reinforcing fillers, i.e., fillers which have a surface 
area of less than 50 m.sup.2 /g, are crushed quartz, diatomaceous earth, 
siliceous chalk such as Neuburg Chalk, calcium silicate, zirconium 
silicate and calcium carbonate, for example, in the form of ground chalk 
and calcinated aluminum silicate. The reinforcing and/or non-reinforcing 
fillers can be treated with trimethylethoxysilane by any technique known 
in the art to render them hydrophobic. 
Fibrous fillers such as asbestos, glass fibers and/or organic fibers also 
can be employed in this composition. Likewise, mixtures of various fillers 
may also be employed. 
The various ingredients of the composition can be mixed in any sequence. 
However, it is preferred that the organosilicon cross-linking agents which 
have at least 3 amino groups and/or acylated amino groups and/or oxime 
groups and condensation catalysts if employed, be the last components 
mixed into the composition. Mixing should be carried out at room 
temperature in the absence of moisture. 
The organopolysiloxane composition can be cured by exposing the composition 
to atmospheric moisture at room temperature. If desired, curing can be 
carried out at temperatures higher than room temperature or at 
temperatures below room temperature, for example, at temperatures of from 
5.degree. to 10.degree. C. and/or by increasing the water concentration 
above that of the atmosphere. 
The improved organopolysiloxane compositions of this invention may be used 
as sealants on horizontal as well as on vertical surfaces. These sealants 
may be applied to substrates which have gaps of from 10 mm to 50 mm such 
as occur, for example, in buildings which are constructed of light 
materials and prefabricated construction components. The improved 
compositions are also suitable for the preventive and restorative coating 
of substrates when it is desired to bridge existing or future fissures 
which occur due to thermal stress, settling and/or shrinkage. 
Such substrates may, for example, be parts of hydraulic installations such 
as sewer pipes, swimming pools and settling basins as well as silos. The 
compositions can be applied to such substrates by any suitable means such 
as, for instance, via spraying and/or brush coating. Coats up to several 
millimeters thick can be applied in a single application. While the 
preventive and/or restorative coatings known heretofore for such 
substrates required several applications, the compositions of this 
invention have the advantage that they can be applied in just one 
application. It is preferable that the improved compositions of this 
invention be applied as a coat of from 0.3 to 2 mm in thickness. 
Various embodiments of the invention are illustrated in the following 
examples in which all parts are by weight unless otherwise specified. 
EXAMPLE 1 
A mixture consisting of 120 parts of a dimethylpolysiloxane having in each 
of its terminal units an Si-bonded hydroxyl group and having a viscosity 
of 80,000 cP at 25.degree. C., 80 parts of a trimethylsiloxy endblocked 
dimethylpolysiloxane which has a viscosity of 35 cP at 25.degree. C., 180 
parts of chalk (calcium carbonate) and 20 parts of pyrogenically produced 
silicon dioxide which has a surface area of 130 m.sup.2 /g is mixed with 
3.0 parts of a product obtained from the reaction of 1 mol 
trimethylchlorosilane and 1.1 mols of 1,2-propylene glycol. The resultant 
composition is then mixed with a mixture consisting of 24 parts of 
methyltris-(sec.-butylamino)-silane and 0.4 part of 3-ethoxypropylamine. 
The composition thus obtained is stored for 24 hours in tightly sealed 
tubes. Subsequently samples are removed from the tubes and the flow 
resistance determined. Also a 5 mm thick coat is applied to a polyvinyl 
chloride foil and cured in the presence of atmospheric moisture. 
EXAMPLE 2 
The process described in Example 1 is repeated except that 3.0 parts of the 
product obtained from the reaction of 1 mol of diphenyldichlorosilane and 
2.2 mols of ethylene glycol are substituted for the product obtained from 
the reaction of trimethylchlorosilane with propylene glycol. 
EXAMPLE 3 
The process of Example 1 is repeated except that 3.0 parts of the reaction 
product of 1 mol dimethyldichlorosilane and 2.2 mols of ethylene glycol 
are substituted for the product obtained from the reaction of 
trimethylchlorosilane with propylene glycol. 
COMISON EXAMPLE 1 
The process of Example 1 is repeated except that the reaction product from 
a halosilane and a bivalent or trivalent alcohol is omitted. 
COMISON EXAMPLE 2 
The process of Example 1 is repeated except that 3.0 parts of 
organo-siloxane-oxyalkylene-block-copolymers corresponding to the 
following average formula 
EQU C.sub.2 H.sub.5 OSi(CH.sub.3).sub.2 O(CH.sub.2 CH.sub.2 O).sub.6 CH.sub.2 
CH.sub.2 CH.sub.2 Si(CH.sub.3).sub.2 [OSi(CH.sub.3).sub.2 ] .sub.11 
-CH.sub.2 CH.sub.2 CH.sub.2 (OCH.sub.2 CH.sub.2).sub.6 O(CH.sub.3).sub.2 
SiO.sub.2 H.sub.5 
are substituted for the product obtained from the reaction of 
trimethylchlorosilane with propylene glycol. The following Table 
illustrates the properties of the compositions and the resultant 
elastomers. 
TABLE 
__________________________________________________________________________ 
Properties - measured 7 days after 
Stability 
applied to the foil 
(flow Elonga- 
Modulus at 
resistance) tion at 
100% elon- 
of com- 
Shore-hardness 
fracture, 
gation, 
pounds as 
Side Side adja- 
DIN 53504 
DIN 53504, 
per DIN 
exposed 
cent to 
Spec. III 
Spec. III 
52454 to air the foil 
percent 
kp/cm.sup.2 
__________________________________________________________________________ 
Example 1 
stable 27 21 not not 
determined 
determined 
Example 2 
stable 29 15 " " 
Example 3 
stable 25 11 410 3.5 
Compari- 
son Exam- 
unstable 
31 26 290 5.4 
ple 1 
Compari- 
son Exam- 
stable 29 26 340 4.5 
ple 2 
__________________________________________________________________________ 
EXAMPLE 4 
A mixture consisting of 60 parts of dimethylpolysiloxane having in each of 
its terminal units an Si-bonded hydroxyl group and having a viscosity of 
80,000 cP at 25.degree. C., 30 parts of a trimethylsiloxy end-blocked 
dimethylpolysiloxane having a viscosity of 35 cP at 25.degree. C., 75 
parts of crushed quartz and 6 parts of pyrogenically produced silicon 
dioxide having a surface area of 130 m.sup.2 /g, is mixed with 2.0 parts 
of the product obtained from the reaction of 1 mol dimethyldichlorosilane 
and 2.2 mols ethylene glycol. The resultant composition is then mixed with 
8 parts of methyltris-(cyclohexylamino)-silane. The thus obtained 
composition is stored in tightly sealed tubes for 24 hours. Thereafter, 
samples are removed from the tubes and the flow resistance is determined. 
A coating 2 mm in thickness is applied to a glazed tile and then cured in 
the presence of atmospheric moisture. 
After 7 days hammer blows are very carefully applied to the back side of 
the tile so as to fracture the tile without scattering the pieces which 
remain in contact with the elastomer. The pieces can then be moved away 
from each other by severl millimeters without tearing the coating. When 
the stress applied to separate the tile pieces is relaxed, the elastomeric 
coating contracts, thereby bringing the tile pieces back into close 
contact. 
COMISON EXAMPLE 3 
The process described in Example 4 is repeated except that the product 
obtained from the reaction of a halosilane and a bivalent alcohol is 
omitted. The compound thus obtained is not resistant to flow and when the 
tile pieces are separated by a few millimeters the coating tears. 
COMISON EXAMPLE 4 
The process described in Example 4 is repeated except that 2.0 parts of the 
organosiloxane-oxyalkylene-block-copolymer employed in Comparison Example 
2 is substituted for the product obtained from the reaction of 
dimethyldichlorosilane with ethylene glycol. The product thus obtained is 
stable, i.e., it resists flow. However, the coating tears when the tile 
fragments are separated by a few millimeters. 
The reaction products obtained from the halosilanes and bivalent or 
trivalent alcohols employed in Examples 1 through 4 are prepared in the 
following manner: 
a. Reaction Product from Dimethyldichlorosilane and Ethylene Glycol 
1. About 903 parts of dimethyldichlorosilane are added below the surface 
and over a period of about 1.5 hours to about 952 parts of ethylene glycol 
with constant agitation and under a pressure of 250 mm Hg (abs.) at room 
temperature while controlling the pressure in the reaction vessel so that 
it is at least 20 mm Hg below that of the surrounding pressure. The 
mixture is then heated to approximately 100.degree. C. for 1.5 hours at a 
pressure which is approximately 20 mm Hg below environmental pressure and 
then allowed to cool to room temperature. 
2. To a mixture containing 372 parts of ethylene glycol, 650 parts 
triethylamine and 1000 parts by volume of anhydrous toluene are added at 
room temperature and with constant agitation 387 parts of 
dimethyldichlorosilane over a period of 1.5 hours. Thereafter, the mixture 
is refluxed for 1 hour. The triethylaminohydrochloride is separated from 
the reaction mixture by filtration and washed with additional toluene. The 
toluene is then distilled from the combined filtrates at 12 mm Hg (abs.) 
and at 50.degree. C. The resultant distillation residue is then filtered. 
b. Reaction Product from Trimethylchlorosilane and 1,2-Propylene Glycol 
The procedure described under (a)1 above is repeated except that 83.6 parts 
of 1,2-propylene glycol and 1085 parts of trimethylchlorosilane are 
substituted for the ethylene glycol and dimethyldichlorosilane. 
c. Reaction Product from Diphenyldichlorosilane and Ethylene Glycol 
About 1,265 parts of diphenyldichlorosilane are added below the surface of 
680 parts of ethylene glycol over a period of 3.5 hours and at a pressure 
of 250 mm Hg (abs.) at 70.degree. C. with constant agitation. The pressure 
in the reaction vessel is controlled so that it does not rise above about 
20 mm Hg below the environmental pressure. Heat is then applied to 
increase the temperature up to about 150.degree. C. at approximately 20 mm 
Hg below environmental pressure over a period of 3 hours and finally the 
mixture is allowed to cool to room temperature. 
Although specific examples of the invention have been described herein, it 
is not intended to limit the invention solely thereto, but to include all 
the variations and modifications falling within the scope of the appended 
claims.