Polysiloxane surfactants useful for foaming polyurethane foams

A polysiloxane surfactant useful in controlling the foaming of a polyurethane foam having the formula, ##STR1## where y is a whole number varying from 15 to 150 and z is a whole number varying from 3 to 16 where R and R' are monovalent hydrocarbon radicals of less than 8 carbon atoms, R.sup.2 is selected from alkylene and arylene radicals of from 11 to 20 carbon atoms, n is an integer that varies from 2 to 4, x varies from 5 to 30 for the case n is equal to 2, x varies from 1 to 40 for the case n is equal to 3 and 4 where there may be ether units with n equal to 2,3, and 4 in the same molecule.

The present invention relates to polysiloxane-oxyalkylene block copolymers 
and, in particular, the present invention relates to 
polysiloxane-oxyalkylene block copolymers which are useful in controlling 
the cell size and density of a polyurethane foam during the foaming 
procedure. 
Polyurethane foams are formed by reacting a polyisocyanate with a polyol 
which may be a polyether containing hydroxyl groups or a polyester 
containing hydroxyl groups in the presence of a blowing agent, a catalyst 
such as tin catalyst, and a surfactant. When the polyisocyanate reacts 
with the polyol, heat is generated which evaporates the blowing agent so 
it passes through the liquid mixture forming bubbles therein. In addition, 
water may be added to the mixture to react with excess polyisocyanate to 
generate carbon dioxide which passes through the mixture forming bubbles. 
If a surfactant is not used in the foaming composition, then the bubbles 
simply pass through the liquid mixture without forming a foam. 
In the past, many surfactants were used to form a foam from the liquid 
mixture, as well as to control the size of the bubbles in the foam so that 
a foam of a desired density was obtained. Preferably, a foam with small 
bubbles or cells therein of uniform size was desired in that it was the 
most desirable foam, that is, a foam having a lower density. As the result 
of research, it was discovered that polysiloxanes having oxyalkylene units 
in the polymer chain were useful as surfactants in foaming polyurethane 
foam. In fact, it was discovered that these polysiloxane-oxyalkylene block 
copolymers were much more efficient surfactants in foaming polyurethane 
foam, that is, a smaller quantity of these surfactants was used to produce 
foams of lower density than was possible with other surfactants. 
One difficulty with these polysiloxane surfactants was that the oxyalkylene 
group was attached by a silicon to oxygen to carbon linkage. This linkage 
proved to be hydrolytically unstable in that as soon as as any water came 
into contact with the surfactant, the silicon to oxygen to carbon linkage 
would be hydrolyzed in a polysiloxane polymer which had an unacceptable 
foaming efficiency for forming polyurethane foams. 
It is to be noted that in forming polyurethane foams rigid foams are formed 
with closed cells, while in flexible foam most of the cells are desirably 
open celled. This is desirable in flexible foams in that a large number of 
closed cells in the foam will impair the breatheability of the foam 
structure and its ability to return to its original shape after it has 
been crushed. Thus, it has been found that polysiloxane polymers which do 
not have oxypropylene moieties attached thereto are unsuitable as foaming 
agents for flexible foam in one aspect in that most of the cells that are 
formed are closed cells. 
Another disadvantage with the present polysiloxane-oxyalkylene block 
copolymers that are used as surfactants for polyurethane foams is that 
they may only be used for flexible or rigid foams and that a common 
formulation that can be used for both flexible and rigid foams with minor 
variation of molecular structure has not been as yet discovered. 
In order to improve the hydrolytic stability of the available 
polysiloxane-oxyalkylene block copolymers, there have been proposed 
polysiloxane-oxyalkylene block compolymers in which there are SiC linkages 
connecting the silicon to the polyether moiety. The polyether moiety has 
an unsaturated olefin group attached to it, which group is reacted with a 
polysiloxane having free hydrogen atoms through an Si-H olefin addition 
reaction to form the desired compound. However, the disadvantage of this 
process for producing polysiloxane-oxyalkylene block copolymers with an 
Si-C linkage is that it is necessary to produce polyethers with an 
unsaturated moiety attached thereto. This involves reacting an unsaturated 
acid, such as an alkenoic acid or unsaturated alcohol, with alkylene 
oxides to produce the unsaturated polyether. Such compounds are only 
commercially available to companies and firms that produce and manufacture 
polyether, for their own particular use. 
Another disadvantage of this process for forming polyethers with an 
unsaturated moiety therein is that it is very difficult to control the 
number and type of oxyalkylene groups in the polyether chain. There is a 
much more simple and efficient way to control the type and amount of 
oxyalkylene groups in the polyether moiety by blending in different types 
of polyethers. However, this is not possible by the process of the prior 
art. 
Accordingly, it is one object of the present invention to provide a 
polysiloxane-oxyalkylene block copolymer in which the oxyalkylene moiety 
is connected to the silicon atom through a silicon-carbon linkage. 
It is another object of the present invention to provide a process for 
producing a polysiloxane-oxyalkylene block copolymer with a silicon-carbon 
linkage connecting the polysiloxane moiety to the oxyalkylene moiety, 
which process is more economical and efficient than prior processes. 
It is still another object of the present invention to provide a 
polysiloxane-oxyalkylene block copolymer surfactant for polyurethane foams 
having silicon-carbon linkages connecting the oxyalkylene moiety to the 
polysiloxane moiety, which surfactant is much more efficient in producing 
both flexible and rigid foams that are the prior art surfactants. 
It is yet another aim of the present invention to provide an alkenoic acid 
polyether condensation product which can be used to add polyether groups 
to a polysiloxane by the use of an SiH-olefin addition reaction. 
These and other objects of the present invention are accomplished by means 
of the invention set forth below. 
Summary of the Invention 
In accordance with the present invention, there is provided a polyurethane 
foam composition formed from a mixture of polyether or polyester, a 
polyisocyanate, a catalyst for catalyzing the reaction between the 
polyether and polyisocyanate, and a polysiloxane surfactant for 
controlling the foam comprising a compound of the formula: 
##STR2## 
where R and R' are monovalent hydrocarbon radicals of less than 8 carbon 
atoms, R.sup.2 is selected from alkylene and arylene radicals of from 11 
to 20 carbon atoms, n is an integer that varies from 2 to 4, x varies from 
5 to 30, for the case n is equal to 2, x varies from 1 to 40 for the case 
n is equal to 3 to 4 where there may be either units with n equal to 2, 3 
and 4 in the same molecule, a is a number varying from 1.51 to 1.99 and b 
varies from 0.019 to 0.45 where the sum of a + b varies from 2.012 to 2.1. 
There is also provided by the present invention a process for producing the 
above surfactant which comprises reacting an alkenoic acid having the 
formula, 
EQU CH.sub.2 =CHR.sup.3 COOH, 
(2) 
with a polyether in the presence of an acid catalyst with the polyether 
selected from the group having the formulas R'(OC.sub.2 H.sub.4).sub.c OH, 
R'(OC.sub.2 H.sub.4).sub.c (OC.sub.3 H.sub.6).sub.d OH, R'(OC.sub.2 
H.sub.4).sub.c (OC.sub.4 H.sub.8).sub.e OH, and R'(OC.sub.2 H.sub.4).sub.c 
(OC.sub.3 H.sub.4).sub.d (OC.sub.4 H.sub.8).sub.e OH to form an 
unsaturated intermediate which is in turn reacted in the presence of a 
platinum catalyst with a hydropolysiloxane having the formula, 
EQU R.sub.a H.sub.b SiO.sub.(4-a-b/2) ( 3) 
where R is a monovalent hydrocarbon radical of less than 8 carbon atoms, 
R.sup.3 is a divalent hydrocarbon radical of from 9 to 18 carbon atoms 
selected from alkylene radicals and arylene radicals, c is a whole number 
varying from 5 to 30, d, e are whole number varying from 0 to 40, a is a 
number varying from 1.51 to 1.99, b varies from 0.019 to 0.45 and the sum 
of a + b varies from 2.012 to 2.1. 
Preferably, the catalyst used in the condensation reaction is toluene 
sulfonic acid and the condensation reaction is carried out at 70.degree. 
to 200.degree. C. Further, preferably, the alkenoic acid is vinyl acetic 
acid, and R in formulas (1) and (3) is preferably methyl. In the compound 
of formula (1), n is preferably equal to 2 throughout the polyether moiety 
with c varying from 5 to 30 in the case where the surfactant is to be used 
for forming rigid foams. In the case of flexible foams, the polyether 
moiety contains both ethylene oxide units and propylene oxide units and 
may contain butylene oxide units where the amount of ethylene oxide units 
varies from 5 to 30, the amount of propylene oxide units and butylene 
oxide units varies from 1 to 40.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The radicals represented by the various symbols appearing in formulas (1), 
(2) and (3) are well known in the art and are typified by the radicals 
usually associated with silicon-bonded organic groups in the case of R and 
are generally associated with monoalkyl ethers or polyalkyl ether glycols 
in the case of R' and the use of a divalent hydrocarbon radical in the 
case of R.sup.2. The organic radicals represented by R include monovalent 
hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and 
cyanoalkyl radicals. Thus, the radicals R and R' may be alkyl, such as 
methyl, ethyl, propyl, butyl, octyl radicals; aryl radicals, such as 
phenyl, tolyl, xylyl, naphthyl, radicals; aralkyl radicals, such as 
benzyl, phenylethyl radicals; olefinically unsaturated monovalent 
hydrocarbon radicals such as vinyl, allyl, cyclohexyl radicals; cycloalkyl 
radicals such as cyclohexyl, cycloheptyl radicals; halogenated monovalent 
hydrocarbon radicals such as chloromethyl, dichlorophropyl, 
1,1,1-trifluoropropyl, chlorophenyl, dibromophenyl and other such 
radicals; cyanoalkyl radicals such as cyanoethyl, cyancpropyl, etc. 
Preferably, the radicals represented by R have less than 8 carbon atoms 
and, in particular, it is preferred that R be methyl, ethyl or phenyl. In 
addition, it is preferred that the radicals represented by R' be lower 
monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon 
radicals and cyanoalkyl radicals of less than 8 carbon atoms. Thus, R' may 
be selected from alkyl radicals containing from 1 to 7 carbon atoms, both 
straight chain and branched chain; aryl radicals such as phenyl, tolyl, 
xylyl, naphthyl, etc. Preferably, R' is a lower alkyl radical with 1 to 4 
carbon atoms, such as methyl, ethyl, propyl and butyl. The divalent 
radical represented by R.sup.2 may be any divalent hydrocarbon radical of 
from 11 to 20 carbon atoms or may be a halogenated divalent hydrocarbon 
radical of less than 20 carbon atoms. The radicals represented by R.sup.2 
may be any alkylene or arylene radicals of from 11 to 20 carbon atoms. 
As pointed out above previously, the method of preparing the 
polysiloxane-oxyalkylene block copolymers is to react the alkenoic acid of 
formula (2) with any monoalkyl or monoaryl ether of polyalkylene glycol 
having the general formula, 
EQU R'(OC.sub.n H.sub.2n).sub.x OH, 
(4) 
where n and x and R' are defined above so as to obtain a monoalkyl glycol 
having the formula, 
##STR3## 
where R' is defined above, R.sup.3 is a divalent hydrocarbon radical 
selected from arylene and alkylene radicals of from 9 to 18 carbon atoms, 
c is a whole number varying from 5 to 30 and d and e are whole numbers 
varying from 0 to 40. This polyalkylene glycol can then be reacted with 
the compound of formula (3) to form the block copolymer of the present 
invention. 
This alkenoic acid, as well as the longer carbon chained alkenoic acids of 
11 or more carbon atoms, are prepared by reacting allyl chloride or the 
longer chain unsaturated olefin chlorides with cuprous cyanide to form the 
allyl cyanide and the longer chain olefin cyanides, as the case may be. 
The polyalkylene glycols within the scope of formula (4) are also well 
known in the art. These materials are formed by reacting a monomeric 
alcohol of the formula R'OH with an alkylene oxide or mixtures of alkylene 
oxides. By controlling the reaction conditions during the reaction between 
the aforementioned monohydric alcohol and the polyalkylene oxide the 
molecular weight of the polyalkylene glycol monoether can be controlled. 
There are only certain polyalkylene glycol monethers which can be employed 
to produce the surfactants of the present case. In any case, there must be 
at least 5 oxyalkylene units in the monoether that is used in the present 
case. In other words, x of formula (4) must be equal to at least 5. As 
indicated by formulas (1) and (4), the polyalkylene glycol monoethers 
contain oxyalkylene groups of from 2 to 4 carbon atoms which include 
within these oxyalkylene groups, for example, oxyethylene, 
oxypropylene-1,2, oxypropylene-1,3 oxybutylene-1,2, etc. The monoethers of 
formula (4) may contain only one type of oxyalkylene groups or a mixture 
of oxyalkylene groups. To produce rigid foams, the polyalkylene glycol 
monoether should contain just ethylene oxide groups. In that case, x 
varies from 5 to 30. It has been found that when the polyalkylene glycol 
monoether contains 5 to 30 oxyethylene groups, that a good surfactant is 
produced for rigid foams. For flexible foams or for semi-rigid foams, 
there should be a mixture of oxyethylene and oxypropylene groups in the 
polyalkylene glycol monoether. For such flexible foams there may be also 
utilized mixtures of oxyethylene and oxybutylene or there may be utilized 
mixtures of oxyethylene, oxypropylene and oxybutylene units in the 
polyalkylene glycol monoether polymer chain. To produce a good surfactant 
for flexible foams or for semi-rigid foams, the number of oxyethylene 
units may vary from 5 to 30 while the number of oxypropylene and 
oxybutylene units may vary from 1 to 40. More preferably, to produce good 
surfactants for flexible foam, there should be 5 to 30 oxyethylene and 10 
to 40 oxypropylene units in the polyalkylene glycol monoether polymer 
chain. For the rigid foams, the surfactant may have a small amount of 
oxypropylene and oxybutylene units in the polymer chain but, in any case, 
no more than 3 of such units should be in the polyalkylene glycol 
monoether chain. Both in the case of the flexible foams and rigid foams, 
the silicon units in the polysiloxane surfactant should comprise 15 to 40% 
by weight of the total molecular weight of the block copolymer. With 
respect to flexible foams, it has been found that it is most advantageous 
to have the silicon units constitute 30 to 33% by weight of the molecular 
weight of the oxyalkylene polysiloxane block copolymer. With low molecular 
weight oxyalkylene polysiloxane copolymers, there can be a little as 15% 
by weight of siloxy units in the polymer chain to obtain an acceptable 
surfactant. By a low molecular weight polymer, it is preferred that the 
oxyalkylene polysiloxane polymer having a molecular weight of 300 to 
3,000. Where the molecular weight of the oxyalkylene polysiloxane block 
copolymer is from 3,000 and above, the siloxy units in the polymer chain 
should constitute more than 15% by weight of the molecular weight of the 
polymer. Preferably, however, the siloxy units should constitute 30 to 33% 
by weight of the molecular weight of the polymer. For further information 
as to the production of the polyalkylene glycol monoethers useful in the 
practice of the present invention, the reader is referred to U.S. Pat. 
Nos. 2,425,755 and 2,448,644. 
The organohydrogenpolysiloxanes within the scope of formula (3) are also 
well known in the art and as indicated by formula (1), the 
organohydrogenpolysiloxane contains an average of 0.019 to 0.45 
silicon-bonded hydrogen atoms per silicon atom. If there is more than 2.00 
total hydrogen atoms and R groups per silicon atom in the 
organohydrogenpolysiloxane of formula (3), it is apparent that the 
polysiloxane is actually a copolymer of two or more different types of 
siloxane units. Thus, the organohydrogenpolysiloxane of formula (3) can be 
described as a copolymer of one or more types of siloxane units having the 
formula, 
EQU (H).sub.f (R).sub.g SiO.sub.(4-f-g/2) (6) 
where R is as previously defined and f is a whole number equal to from 1 to 
2, inclusive, preferably 1, g is a whole number equal to from 0 to 2, 
inclusive, and the sum of f and g is equal to 1 to 3, inclusive, together 
with one or more types of siloxane units having the formula, 
EQU (7) (R).sub.h SiO.sub.(4-h/2) (7) 
where R is as previously defined and h is a whole number equal to from 0 to 
3, inclusive. The proportions and types of siloxanes used in formula (6) 
and the siloxane units of formula (7) are selected so as to produce the 
copolymer containing from 0.019 to 0.45 hydrogen atoms per silicon atom 
and from 1.51 to 1.99 R groups per silicon atom with the sum of the 
numbers of hydrogen atoms and R groups to be equal to from 2.012 to 2.1 
per silicon atom. 
The organopolysiloxanes within the scope of formula (3) can be prepared by 
the cohydrolysis of one or more hydrogen-containing chlorosilanes such as 
trichlorosilane, dichlorosilane and methylhydrogendichlorosilane, 
phenylhydrogendichlorosilane, dimethylhydrogenchlorosilane, 
methylphenylhydrogenchlorosilane, etc., with one or more other 
organochlorosilanes, such as methyltrichlorosilane, dimethylchlorosilane, 
trimethylchlorosilane, methylphenyldichlorosilane, to produce the desired 
siloxanes. 
Another method which is more preferred is to form cyclics from the 
chlorinated siloxanes and then to react the cyclics to produce the desired 
hydropolysiloxanes. Thus, methylhydrogentetracyclosiloxane may be reacted 
or equilibrated with dimethyltetracyclosiloxane to produce the desired 
polysiloxanes. Hexamethyldisiloxane is also added to the reaction mixture 
to produce the chain-stopped units for the polymer chains. By this method 
they can produce the preferred type of organohydrogensiloxanes within the 
scope of formula (3) used in preparing the polysiloxane-oxyalkylene 
copolymers of the present invention. The preferred polymer produced in 
accordance with the above method which is within the scope of formula (3) 
are the triorganosilyl chain-stopped copolymers of diorganosiloxane units 
and organohydrogensiloxy units having the formula, 
##STR4## 
where R is as previously defined and preferably methyl, y is a whole 
number which may vary from 15 to 150 and z is a whole number varying from 
3 to 16, where the sum of y plus z may vary from 18 to 166. In the 
formula, z must have a value of at least 3 in order to produce the 
preferred polysiloxane-oxyalkylene block copolymers of the present case, 
in that there must be at least 3 hydrogen groups in the polymer chain to 
which can be added at least 3 polyalkylene glycol monoether units. With 
less than 3 polyalkylene glycol monoether units in the polymer chain, a 
good surfactant is not formed either for flexible foams or rigid foams. 
The reaction for producing the polyalkylene glycol monoether of formula (4) 
is fairly straight-forward. Depending upon the use for which the 
surfactant is intended, whether for rigid foams or for flexible foams, a 
blend of the desired polyalkylene glycol monoethers is first prepared. A 
blend of polyalkylene glycol monoethers is not necessary when the 
surfactant is to be used for rigid foams, since only ethylene oxide units 
are desired in the polyalkylene glycol monoether. However, in preparing a 
surfactant for flexible foams, it is preferable to blend a number of 
commercially available polyalkylene glycol monoethers so that the final 
product will have the desired ethylene oxide and propylene oxide and/or 
butylene oxide units in the monoether polymer chain. 
The polyalkylene glycol monoether blend is then reacted with the alkenoic 
acid in approximately molar amounts. An excess of the alkenoic acid may be 
used to insure all the polyalkylene glycol monoethers will react in a 
condensation reaction with an alkenoic acid. The two reactants are 
preferably present in a solvent which may be selected from any inert 
organic solvent such as benzene, toluene, xylene, cyclohexane, and mineral 
spirits. The solution of the reactants is then heated to the reflux 
temperature of the solvent which may vary anywhere from 70.degree. to 
200.degree. C and the water of esterification can then be preferably 
removed by any appropriate azeotropic procedure. The reaction is allowed 
to proceed to completion in about 5 to 15 hours. In order for the reaction 
to be completed in 5 to 10 hours, there is preferably used a catalyst in 
the reaction mixture. Such a catalyst may be, for example toluene sulfonic 
acid, which is not a particularly strong acid. A stronger acid, such as 
sulfuric or hydrochloric acid, is not desirable as a catalyst since it 
will cleave the oxyalkylene linkages. 
Another suitable catalyst is sodium hydrogen sulfate and other similar 
types of acids. After the 5 to 10 hour period the solution is cooled to 
below 70.degree. C and sodium carbonate and water are added to neutralize 
the acid catalyst, and the excess alkenoic acid. The water is then 
azeotroped out at a temperature of 70.degree. to 100.degree. C and the 
mixture cooled to 30.degree. C so that the salt that is precipitated out 
can be filtered from the solution. The toluene, xylene or other type of 
solvent used in the reaction mixture can then be stripped off under vacuum 
at a pot temperature of 50.degree. to 100.degree. C to leave behind the 
alkenyl glycol monoether. A small amount of solvent can be left behind 
with the alkenyl monoether since it does not have any effect whatsoever on 
the SiH-olefin addition reaction to which the alkenyl polyether is 
subjected. In fact, the inert solvent is removed solely for the purpose of 
determining whether the alkenyl polyether is obtained from the reaction. 
In any event, the reaction product from the condensation reaction is a 
polyether with terminal vinyl groups. To this alkenyl polyether there is 
added the organohydrogenpolysiloxane of formula (3) in the presence of a 
catalyst which promotes the addition of the SiH group on the 
organohydrogenpolysiloxane across the double bonds of the vinyl-terminated 
polyether. When there is only one hydrogen group in the 
hydrogenpolysiloxane of formula (3), there is added equivalent molar 
amounts of the alkenyl polyether to the hydrogenpolysiloxane. Preferably, 
there is added 5 to 10 mole percent excess of the alkenyl polyether based 
on the number of silicon-bonded hydrogen groups in the 
hydrogenpolysiloxane. The purpose of the excess of the unsaturated groups 
is to insure that the reaction removed all of the silicon-bonded hydrogen 
groups so that none is present in the final product. Preferably, also, the 
reaction is carried out in an inert solvent which may be selected friom 
benzene, toluene, xylene, cyclohexane and mineral spirits. If the reaction 
is not carried out in solvent, then the reaction mixture gels as the 
reaction proceeds. The reaction mixture is heated to 50.degree. to 
100.degree. C and the reactants are allowed to react for a period varying 
from 1 to 10 hours and, preferably from 2 to 5 hours. 
Suitable catalysts for addition of the organohydrogenpolysiloxane to the 
alkenyl polyether are the various platinum and platinum compound catalysts 
known in the art. These catalysts include elemental platinum in a finely 
divided state which can be deposited on charcoal or alumina, as well as 
various platinum compounds such as chloroplatinic acid, the platinum 
hydrocarbon complex of the type shown in U.S. Pat. Nos. 3,159,601 and 
3,159,662, as well as the platinum alcoholic complexes prepared from 
chloroplatinic acids which are described and claimed in Lamoreaux U.S. 
Pat. No. 3,220,972. Preferably, the platinum catalyst is added to the 
organohydrogenpolysiloxane located in the reaction chamber to which is 
also added a solvent and then the alkenyl polyether is slowly added to the 
reaction mixture at the reaction temperatures described above. 
A preferred hydrogenpolysiloxane coming within the scope of formula (3) is 
one having a hydrogen group at a terminal position of the polymer chain as 
well as a hydrogen group in the center position of the polymer chain. Such 
a hydrogenpolysiloxane has generally the formula 
##STR5## 
where y is a whole number varying from 15 to 150, z is a whole number 
varying from 3 to 16, and the sum of y plus z varies from 18 to 166. This 
compound may easily be prepared by reacting the proper moles of 
dihydrotetramethyldisiloxane as the terminal chain-stopper, with 
tetramethylhydrogencyclosiloxane and tetradimethylcyclosiloxane. The 
equilibration reaction products obtained when the above reactants are 
equilibrated in the presence of potassium hydroxide at a temperature about 
100.degree. C is the compound whose structure is set forth above in 
formula (9). When the compound within the scope of formula (9) is used in 
the SiH-olefin addition reaction, one mole of the compound is reacted with 
3 moles or more of the alkenyl polyether of formula (5). The resulting 
compound obtained by the SiH-olefin addition reaction has polyether groups 
in the terminal position of the polysiloxane chain, as well as polyether 
units in the center of the polysiloxane chain. Whether elemental platinum 
or one of the platinum compound catalysts or a platinum complex catalyst 
is used, the catalyst is generally used in an amount sufficient to provide 
about 10.sup.-4 to 10.sup.-6 moles of platinum per mole of the alkenyl 
polyether of formula (5). As mentioned previously, the reaction is 
effected by adding the hydrogenpolysiloxane to the group of solvents 
discussed previously and then the mixture is heated to 70.degree. to 
130.degree. C. At this temperature there is added the platinum catalyst 
such that the catalyst is dispersed throughout the hydrogenpolysiloxane. 
The alkenyl polyether may then be added dropwise over a 2 to 3 hour period 
or added in a bulk amount and the reaction allowed to proceed to 
completion for a period of time varying from 4 to 10 hours. Throughout the 
reaction period, the reaction temperature is maintained at the temperature 
range of 70.degree. to 130.degree. C and preferably at a temperature range 
of 70.degree. to 100.degree. C. After the reaction period is over, a 
sample of the reaction mixture may be checked by infrared analysis of SiH 
bonds to determine how far the reaction has proceeded to completion. When 
at least 95% of the SiH polysiloxane has been converted to the copolymers, 
then the reaction mixture may be cooled and the reaction may be considered 
to have proceeded to a sufficient extent for the conversion of the 
oxyalkylene polysiloxane copolymer. A buffer is then added to the reaction 
mixture. The resulting copolymer with the buffer therein may then be 
cooled to room temperature and filtered to remove the platinum catalyst 
therefrom. 
The buffer which is added to the copolymer improves the shelf life of the 
copolymer since it raises its pH in the range of 7 to 9. This level of pH 
eliminates acid radicals from the copolymer product. Strong acids may 
attack and break the carboxyl group linkage connecting the polyether 
groups with the siloxy groups. By raising the pH of the copolymer product 
to a level of 7 to 9, there is assured that there is no free acid mixed in 
with the product, and thus the product which is thus neutralized can be 
stored for extended periods of time without any degradation of the polymer 
taking place. The copolymer surfactant as produced can then be mixed with 
polyurethane foam mixtures prior to their foaming so as to allow the 
polyisocyanate and polyol which form the polyurethane initial foaming 
mixture to foam in a desirable manner so as to produce a low density foam 
with cells therein of small, uniform cell size. 
The polyisocyanates which are useful in the practice of the present 
invention are those well known polyisocyanates which are conventionally 
used in the manufacture of polyurethane foams. Generally speaking, the 
polyisocyanates contain at least two isocyanate groups per molecule with 
the isocyanate groups being separated from each other by at least three 
carbon atoms, i.e., the isocyanate groups are not on adjacent carbon atoms 
in the polyisocyanate. These polyisocyanates can be aromatic or aliphatic, 
and can be characterized by the formula, 
EQU Y(N=C=O).sub.f 
where Y represents a polyvalent organic radical having a valence f, where f 
has a value of at least 2, and preferably from 2 to 3, inclusive. The 
number of isocyanate groups is, of course, equal to the number of free 
valences in the radical Y. In general, the radical Y consists preferably 
of carbon and hydrogen atoms on ly, but can also include oxygen atoms, 
Preferably also, the radical Y is a mononuclear aromatic radical. 
Illustrative of the various polyisocyanates which can be employed in the 
practice of the present invention can be mentioned, for example 
2,4,-toluene diisocyanate; m-phenylene diisocyanate; 
methylene-bis-(4-phenylisocyanate); 4-methoxy-m-phenylene diisocyanate; 
1,6-hexamethylene diisocyanate; 2,4,6-toluene triisocyanate; 
2,4,4'-diphenylether triisocyanate; 2,6-toluene diisocyanate; 
3,3'-bitolyene-4,4'-diisocyanate; diphenylmethane-4,4'-diisocyanate; 
3,3'-dimethyldiphenylmethane-4,4'-diisocyanate; triphenylmethane 
triisocyanate; diansidine diisocyanate; etc. In addition to using only a 
single isocyanate in the production of polyurethane foams, it is also 
contemplated that mixtures of various isocyanates can be employed. 
The polyols employed in the practice of the present invention are those 
polyols conventionally used in the manufacture of polyurethan foam 
products. Chemically, these materials fall into one of two general 
categories. The first is the hydroxyl-containing polyester and the second 
is the hydroxyl-containing polyether. The polyesters are conventionally 
formed by the reaction of a polyhydric alcohol with a dibasic acid. The 
polyhydric alcohol is employed in excess so that the resulting material 
contains free hydroxyl groups. Illustrative to the types of 
polyester-polyol materials employed in the production of polyurethane 
foams are polyesters formed by the reaction between dibasic acids, such as 
adipic acid, with polyhydric alcohols, such as ethylene glycol, glycerine, 
pentaerithritol, sorbitol, and the like. In general, these polyester 
polyols are prepared so as to contain from about 2 to about 8 hydroxyl 
groups per molecule. 
The polyether polyols employed in the practice of the present invention for 
the manufacture of polyurethane foams can be subdivided into two groups, 
the first of which is a polyalkylene glycol, such as polyethylene glycol 
or polypropylene glycol, or mixed polyethylene-polypropylene glycol. The 
second type is polyoxyalkylene derivative of a polyhydric alcohol, such as 
a polyoxyalkylene derivative of glycerine, trimethylol ethane, trimethylol 
propane, neopentaglycol, sorbitol, sucrose, etc. These materials are well 
known in the art and are prepared by effecting reaction between an 
alkylene oxide or a mixture of alkylene oxides and the polyhydric alcohol. 
One common type of material is prepared by reacting 1,2-propylene oxide 
with glycerine to form a triol containing three polyoxypropylene segments 
attached to the glycerine nucleus. 
These polyester polyols and polyether polyols are characterized by 
molecular weights of the order of 350 to 10,000. The type of 
polyurethanefoam desired -- flexible, semi-rigid, or rigid -- will 
determine the functionality and molecular weight of the polyol used. In 
general, either the polyester polyol or the polyether polyol can be used 
interchangeable in the manufacture of either rigid polyurethane foams, 
semi-rigid polyurethane foams or flexible polyurethane foams. In general, 
the polyols used in the formation of rigid foams have molecular weights in 
the range of from about 350 to 1,000. Generally, these polyols are triols 
or higher polyols. For the manufacture of semi-rigid foams, the polyol has 
a molecular weight in the range of about 1,000 to 2,500 and is generally a 
triol or a mixture of a triol with polyols of higher functionality. For 
the manufacture of flexible foams, the polyol has a molecular weight of 
the range of from about 2,500, up to 10,000 and is a triol or a mixture of 
triol and a diol. 
Along with the polyisocyanate and the polyol, a blowing agent is found in 
the polyurethane foam reaction mixture. The foams are usually blown with 
carbon dioxide, halocarbon or a mixture of each. Water included in the 
foam formulation reacts with the isocyanate groups and results in the 
liberation of carbon dioxide which serves as a blowing agent. However, it 
is often not desirable to form the low density foams using the carbon 
dioxide generated in situ as the only blowing agent, since the generation 
of carbon dioxide also results in cross-linking of the foam through 
di-substituted urea linkages. A high level of such linkages results in 
stiffer foams than would be obtained otherwise. 
Accordingly, in those cases where soft foams are desired, the reaction 
mixture often includes a separate blowing agent, such as a low boiling, 
inert liquid. The ideal liquid is one which has a boiling point slightly 
above room temperature, i.e., a temperature of about 20.degree. to 
25.degree. C so that the heat generated by the exothermic reaction between 
the hydroxyl groups and the isocyanate will warm the reaction mixture to a 
temperature above the boiling point of the liquid blowing agent and 
vaporize it. Suitable blowing agents include alkanes having appropriate 
boiling points but the most desirable blowing agents have been found to be 
trichlorofluoromethane or methylene chloride. 
In rigid foams intended for thermal insulation, halocarbons are often used 
exclusively as blowing agents because of the low thermal caonductivity of 
halocarbons as opposed to carbon dioxide or air. Trichlorofluoromethane is 
the preferred blowing agent for conventional systems, while a mixture of 
trichlorofluoromethane and dichlorodifluoromethane is used in the well 
known frothing processes. 
Other ingredients often found in the polyurethane foam reaction mixture are 
various catalyst. For example, it is often desirable to add a catalyst to 
facilitate the reaction between water present in the reaction mixture and 
isocyanate groups. A typical type of catalyst for this reaction is a 
tertiary amine catalyst. These amine catalysts and their use are well 
known in the art and include materials such as N-methylmorpholine, 
dimethylethanol amine, triethyl amine, N,N'-diethylcyclohexyl amine, 
dimethylhexadecyl amine, dimethyloctadecyl amine, dimethylcocoamine, 
dimethylsilyl amine, N-cocomorpholine, triethylene diamine, etc. 
To catalyze the reaction between the hydroxyl groups of the polyol and the 
polyisocyanate, polyurethane foam reaction mixtures often contain a 
catalyst comprising a metal salt of an organic carboxylic acid. Most 
often, this curing agent is a tin salt, such as tin stearate, dibutyl tin 
dilaurate, tin oleate, tin octoate, etc. 
The proportions of the various components of the polyurethane foam reaction 
mixture may vary within wide limits as is well known in the art. When 
water is added to the reaction mixture, it is present in an amount 
sufficient to generate the amount of carbon dioxide desired. Generally, 
when water is employed, it is present in an amount up to about 5 parts per 
100 parts by weight of the polyol. The polyisocyanate is generally present 
in an excess over the amount theoretically required to react with both the 
hydroxyl groups of the polyol and any water present in the reaction 
mixture. Generally, the polyisocyanate is present in an excess equal to 
about 1 to 15% by weight. When a tertiary amine catalyst is present in the 
reaction mixture, it is generally employed in an amount equal to from 
about 0.001 to 3.0 parts per 100 parts by weight of the polyol. When a 
metal salt curing agent is present, it is generally employed in an amount 
equal to from about 0.1 to 1.0 part per 100 parts by weight of the polyol. 
When a separate blowing agent is employed, it is generally employed in an 
amount equal to from about 1 to 50 parts per 100 parts by weight of the 
polyol. 
When employing the siloxane-oxyalkylene copolymer of formula (1) as an aid 
in the formation of polyurethane foams, the copolymer is generally present 
in an amount equal to from about 0.25 to 4.0 parts by weight per 100 parts 
by weight of the polyol or mixture of polyols in the reaction mixture. 
While satisfactory results are obtained using amounts of the copolymer in 
excess of about 4.0 parts per 100 parts by weight of the polyol, e.g., up 
to about 7.5 parts, no particular advantage is obtained in employing more 
than the 4.0 parts by weight. 
Polyurethane foams can be prepared by one of two general methods employing 
the siloxane-oxyalkylene copolymer of formula (1). In the first and 
preferred process, all of the reactants are rapidly mixed together and the 
reaction mixture is allowed to foam. After foaming has been completed, the 
resulting foam can be cured if desired by heating at elevated 
temperatures, e.g., a temperature of from about 75.degree. to 125.degree. 
C for several hours. Alternatively, the foam can be stored at room 
temperature until complete cure has been effected in times of from 24 
hours to 48 hours or more. 
In the second process, a prepolymer is formed from the polyol and the 
polyisocyanate to give a prepolymer containing excess polyisocyanate. This 
prepolymer is then mixed with the other reactants, such as water, tertiary 
amine catalyst, blowing agent, curing catalyst, and siloxane-oxyalkylene 
copolymer of formula (1) and allowed to foam. In a modification of the 
second process, the polyisocyanate and a portion of the polyol are reacted 
together to form a base resin. When foaming is desired, the remainder of 
the polyol, as well as the other ingredients of the reaction mixture, are 
added to the base resin and the mixture is stirred and allowed to foam. 
Again, curing can be effected at room temperature or at an elevated 
temperature. 
Regardless of the foaming process in which the polysiloxane-oxyalkylene 
copolymer of formula (1) is employed, and regardless of whether the 
components of the reaction mixture are such as to produce rigid foams, 
semi-rigid foams or flexible foams, the use of these copolymers results in 
foams having small, uniform cells and desirably low densities. 
Because of the complexity of the well known technology surrounding the 
manufacture of polyurethane foam of all types, no attempt will be made 
hereto discuss the many variations in technique and formulations which can 
be employed. For further details on the technology of polyurethane foams, 
reference is made to the voluminous patent and technical literature on the 
subject, especially "Chemistry and Technology," volumes I and II, J. 
Saunders and K. Frisch, Interscience, New York (1964). 
The following examples are illustrative of the practice of the invention 
and are not intended for purposes of limitation. All weights are given in 
parts unless otherwise specified. 
EXAMPLE 1 
To a three-neck, two-liter glass flask equipped with an agitator, 
thermometer, heating mantle and Dean Stark trap condenser is added 200 
parts of a polyether which has a formula of C.sub.4 H.sub.9 (OC.sub.2 
H.sub.4).sub.18 (OC.sub.3 H.sub.6).sub.25 OH to 100 parts of a polyether 
which has a formula of C.sub.4 H.sub.9 (OC.sub.2 H.sub.4).sub.28 (OC.sub.3 
H.sub.6).sub.24 OH and 100 parts of a polyether which has a formula of 
C.sub.4 H.sub.9 (OC.sub.2 H.sub.4).sub.14 (OC.sub.3 H.sub.6).sub.22 OH. 
The use of these polyethers in the weight ratio of 50, 25 to 25, resulted 
in a polyether blend with the average composition C.sub.4 H.sub.9 
(OC.sub.3 H.sub.6).sub.22 (OC.sub.2 H.sub.4).sub.20 OH. To this polyether 
blend there is added 350 parts of toluene, 24.2 parts vinyl acetic acid 
and 8.0 parts of Witco TX acid, which is a commercial grade toluene 
sulfonic acid. The solution is heated to reflux at a temperature of 
approximately 118.degree. C and the water of esterification is removed 
from the system by azeotroping with the Dean Stark trap. By checking the 
reaction periodically as it proceeds by weak acid titration, it is 
determined that the reaction is completed in 5.5 hours. 
The solution is then cooled to 55.degree. to 60.degree. C, sodium carbonate 
and water are added to neutralize the toluene sulfonic acid and the excess 
vinyl acetic acid so as to terminate further reaction or effect on the 
product by the remaining acid. The reaction mixture is neutralized to a 
total acid number of less than 0.10 milligrams KOH per gram of sample. The 
water is then azeotroped out, the mixture cooled to 30.degree. C and the 
salts are filtered out. The filtered polyether toluene solution is 
stripped of toluene at 5 mm of mercury under nitrogen to a pot temperature 
of 70.degree. C. The resulting material contained approximately 5% 
toluene, had a viscosity of 350 centistokes at 25.degree. C and an average 
structure as that set forth in the following formula: 
##STR6## 
EXAMPLE 2 
To a 500 ml three-neck glass flask equipped with agitator, thermometer, 
dropping funnel and condenser there is added 80 mg. of previously dried 
toluene and 25.0 parts of SiH-containing silicone fluid of an average 
composition, 
##STR7## 
This mixture is heated to 70.degree. C and at that time 0.3 ml of 
Lamoreaux's platinum catalyst is added. Then there is commenced the 
dropwise addition of 83 parts of vinyl-stopped polyether which is the 
product of Example 1 which dropwise addition is continued for 2.5 hours. 
The amount of vinyl-stopped polyether is 10% in excess of the amount 
necessary to react with the SiH-containing silicone fluid. An hour after 
the end of this dropwise addition, an additional amount of 0.10 ml of 
catalyst is added and the reaction continued for another hour. Turning the 
reaction procedure, the pot temperature is held at 70.degree. .+-. 
3.degree. C throughout the reaction. The reaction is allowed to proceed 
for a total time of 4.5 hours. The reaction mixture is then cooled to 
25.degree. C and sampled for percent conversion. Based on the infrared 
peak for SiH 4.6 m, the reaction is 96.1% complete. 
To the reaction mixture there is added 0.5 g of triethanol amine which is 
used to raise the pH of the product to between 7 and 9 so as to eliminate 
free acid groups from the reaction product, which free acid groups would 
attack the carboxyl linkage and degrade the polymer. The toluene solvent 
is then stripped off the reaction product at 5 mm mercury under nitrogen 
with a pot temperature of 80.degree. C. The copolymer product is cooled to 
25.degree. C and filtered. The resulting copolymer has no SiH peak at 4.6 
m, a viscosity of 13,147 centistokes at 25.degree. C and has the following 
structure: 
##STR8## 
EXAMPLE 3 
There is prepared by the method of Examples 1 and 2 samples of the 
following three surfactants: 
##STR9## 
These surfactants were used in the standard polyurethane foam test to 
produce samples of foams. The surfactants were used at different 
concentrations of parts surfactant per 100 parts of polyol to obtain the 
different foam samples. There are also subjected to the same test control 
A and control B which are two of the best polyurethane surfactants for 
flexible foams presently available on the market. The densities of the 
foams obtained by the use of the different surfactants and at different 
concentrations are shown in Table 1 below in pounds per cubic foot. There 
is also listed the bun foam height in inches obtained at the different 
concentrations of surfactant. Since the same amount of the ingredients is 
used in each sample that was run, with the exception that the surfactant 
concentration is varied, there is indicated by the bun height results the 
amount of foam that is produced by a particular surfactant at a particular 
concentration of surfactant in the foam. 
TABLE I 
______________________________________ 
Concen- 
tration of 
Surfactant 
Foam Densities lbs/ft.sup.3 
Bun Height, in. 
phr 0.5 0.6 0.8 1.0 0.5 0.6 0.8 1.0 
______________________________________ 
Control A 
1.35 1.36 1.32 1.31 10 9 3/4 
10 1/2 
10 3/4 
Surfactant A 
1.32 1.30 1.27 1.28 10 1/2 
11 11 3/4 
11 1/2 
Surfactant B 
1.35 1.32 1.31 1.29 10 10 1/2 
10 3/4 
11 1/4 
Control B 
1.34 1.34 1.34 1.31 10 1/4 
10 1/4 
10 1/4 
10 3/4 
Surfactant C 
1.31 1.32 1.30 1.31 10 3/4 
10 1/2 
11 10 3/4 
______________________________________ 
It can be seen from this table that at the same surfactant concentration, 
the foam densities using the surfactants of the present case are at least 
the same and, in most cases, are better than the foam densities obtained 
using surfactants Control A and Control B which are the surfactants 
presently on the market. The lower the foam density that is obtained, the 
more efficient is the surfactant at a particular concentration. As a 
result, it can be concluded from this table that the surfactants of the 
present case are at most concentrations more efficient than the 
surfactants of the prior art. 
Further, the data in the bun height columns indicates that at least the 
same amount of foam and in most cases more foam is produced at a 
particular surfactant concentration by the surfactants of the present case 
than is produced by the surfactants of the prior art. 
EXAMPLE 4 
There is separated out four samples of Surfactant A of Example 1. Two of 
the samples are set aside and aged for 25 days and 90 days, respectively, 
and then are used at a concentration of 0.6 phr to produce foams in 
accordance with the standard polyurethane foam test. Five parts of one of 
the remaining two samples is taken and mixed with 44 parts of water and 
aged for 25 days at 25.degree. C. Then 4.9 parts of this blended sample is 
taken and used per 100 parts of polyol to prepare a foam in accordance 
with the standard polyurethane foam test. From the fourth sample there was 
taken 5 parts of the surfactant and mixed with 44 parts of water. This 
fourth sample, a water-surfactant blend, is aged to 90 days at 25.degree. 
C. At the end of this period, 4.9 parts of the water-surfactant blend, 
aged for 90 days, is used to prepare a foam in accordance with standard 
polyurethane foam tests. The results of these tests in density of foam and 
foam height are shown in Table II below. 
TABLE II 
______________________________________ 
Foam Density 
Foam Height 
Days of Aging 0 25 90 0 25 90 
______________________________________ 
Surfactant A 1.37 1.37 1.38 9" 9" 8 3/4" 
Surfactant -- 1.38 1.39 -- 8 3/4" 
8 1/2" 
A/H.sub.2 O Blend 
______________________________________ 
It can thus be seen from these results that there is no appreciable 
difference in the change in foam density between the sample of Surfactant 
A that was blended with the water and the portion of Surfactant A that was 
not blended with the water. 
It can be seen from these results that there is only a small change in 
density in the foams produced by the use of Surfactant A blended with 
water and aged 25 days and the surfactant not blended with water and aged 
25 days. After the blended and unblended samples of Surfactant A have been 
aged for 90 days, there is still only a one-hundredth difference in foam 
density in the foam produced. It can also be seen from the above data that 
the aging of the unblended surfactant for 25 days has no variation at all 
on the density of the foam produced. It can also be seen from this data 
that the aging of the unblended and blended surfactant for 90 days only 
produces a change in foam density in the one-hundredth decimal point.