Equilibration of siloxanes
View Patent ↗The invention relates to a process for the preparation of equilibration products of organosiloxanes by rearrangement of the siloxane bond to a cation exchange resin, the organopolysiloxanes thus obtainable and the use thereof.
1. An equilibrated organopolysiloxane obtained by a process comprising reacting at least two organosiloxanes in the presence of a macrocrosslinked polystyrene divinylbenzene based cation exchange resin containing sulfonic acid groups at temperature of about 10° C. to about 120° C., optionally in the presence of a solvent, and isolating the equilibrated organosiloxanes, wherein the said macrocrosslinked cation exchange resin has
(a) a maximum uniformity coefficient of 1.6;
(b) a bead size of 16-40 U.S. mesh;
(c) an effective bead size of 0.50-0.62 mm;
(d) a fines content of 0.5% based on the weight of the resin;
(e) a density of 1.15 g/mL;
(f) a water retention of 57-63%;
(g) a surface area of about 33 m 2 /g;
(h) a pore volume of about 0.45 cm 3 /g;
(i) a pore diameter of 41 nm;
(j) stability over a temperature range of 34-284° F.;
(k) a maximum storability of 2 years; and
(l) a storability temperature range of 34-104° F.
2. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the at least one of the organosiloxanes has at least one Si—H group.
3. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the organosiloxanes are low molecular weight organopolysiloxanes.
4. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the low molecular weight organopolysiloxanes have between 2 and 200 silicon atoms.
5. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the solvent is an aliphatic hydrocarbon.
6. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the isolated equilibrated organosiloxane is an organopolysiloxane.
7. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the temperature is about 35 to about 100° C.
8. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the organosiloxanes have viscosity of up to about 10,000 cP at room temperature.
9. The equilibrated organopolysiloxane as claimed in claim 1 , wherein the process carried out continuously.
10. The equilibrated organopolysiloxane according to claim 9 , wherein the equilibrated organosiloxanes are isolated by fractional distillation and the fraction having the desired boiling range is separated from the fraction(s) having equilibrated organopolysiloxanes having the undesired boiling range(s) and removed and the fraction(s) having the undesired boiling range(s) are recycled back into the feed of the continuous process.
11. The equilibrated organopolysiloxane as claimed in claim 1 , wherein at least one of the organosiloxanes is hexamethyldisiloxane, poly(methyl)hydrogensiloxane or a cyclic siloxane.
12. The equilibrated organopolysiloxane according to claim 1 wherein the equilibrated organosiloxanes are further reacted with at least one allylpolyethylene in the presence of a platinum metal complex.
13. A method for stabilizing a flexible polyurethane foam which comprises adding the equilibrated polysiloxane of claim 1 to a mixture comprising a polyetherpolyol and an isocyanate.