Continuous production of aminofunctional siloxanes
Aminoalkyl-functional siloxanes are prepared efficiently by a continuous process in which a cyclic silazane and a hydroxyl-functional siloxane are fed continuously to a reaction zone, reacted in the reaction zone, and the aminoalkyl product and any unreacted starting materials are removed from the reaction zone. The process is effective even with hydroxyl-functional siloxanes having a very low weight percentage of hydroxyl groups.
1 - 11 . (canceled)
12 . A continuous process for the production of amino-functional organosiloxane of the formula III
(SiO 4/2 ) k (R 1 SiO 3/2 ) m (R 1 2 SiO 2/2 ) p (R 1 3 SiO 1/2 ) q [O 1/2 SiR 1 2 —R—NH 2 ] s [O 1/2 H] t (III),
comprising:
continuously feeding to a reaction zone, an organosiloxane of formula IV
(SiO 4/2 ) k (R 1 SiO 3/2 ) m (R 1 2 SiO 2/2 ) p (R 1 3 SiO 1/2 ) q [O 1/2 H] r (IV),
and continuously feeding to said reaction zone a cyclic silazane of the formula V
and reacting said organosiloxane of formula IV and cyclic silazane of formula V in said reaction zone,
R is a divalent Si—C— and Si—N-bonded, optionally cyano- or halogen-substituted C 3-15 hydrocarbon radical in which one or more non-neighboring methylene units may be replaced by —O—, —CO—, —COO—, —OCO— or —OCOO—, —S— or —NR x - groups and in which one or more non-neighboring methine units can be replaced by —N═, —N═N— or —P═ groups, at least 3 and not more than 6 atoms being arranged between the N-bonded silicon atom and the nitrogen atom of the ring;
R x is hydrogen or a C 1-10 hydrocarbon radical optionally substituted by —CN or halogen;
R 1 is a hydrogen atom or a monovalent Si—C-bonded C 1-20 hydrocarbon radical or C 1-15 hydrocarbonoxy radical optionally substituted by —CN, —NCO, —NR x 2 , —COOH, —COOR x , -halogen, -acryloyl, -epoxy, —SH, —OH or —CONR x 2 , wherein one or more non-neighboring methylene units may be replaced by —O—, —CO—, —COO—, —OCO— or —OCOO—, —S— or —NR x - groups, and wherein one or more non-neighboring methine units may be replaced by —N═, —N═N— or —P═ groups,
R 2 may be hydrogen or a C 1-10 hydrocarbon radical optionally substituted by a —CN or halogen or may be a radical of the formula VIII
in which
R 3 is hydrogen or a C 1 -C 10 -hydrocarbon radical optionally substituted by —CN, —NR x or halogen,
e is a whole number greater than or equal to 0,
s is a whole number of at least 1,
r is a whole number of at least 1,
s+t have the value of r and
k+m+p+q have values of at least 2,
and then continuously removing amino-functional organosiloxane of formula III and any unreacted organosiloxane IV and silazane V from the reaction zone.
13 . The process of claim 12 , wherein the reactor is selected from the group consisting of continuous kneaders, extruders, glass reactors, static mixers, and dynamic mixers.
14 . The process of claim 12 , in which R is a straight-chain C 3-6 alkylene radical optionally substituted by halogen atoms.
15 . The process of claim 12 , wherein R 1 is methyl, ethyl, phenyl, vinyl or trifluoropropyl.
16 . The process of claim 12 , wherein the sum of k, m, p, q, s and t is a number from 2 to 20,000.
17 . The process of claim 12 , wherein resins are prepared in which 5% <k+m <90%, based on the sum of k, m, p, q, r, s and t.
18 . The process of claim 12 , wherein a linear organosiloxane of the formula VI
[H] u [H 2 N—R—SiR 1 2 ] v O(SiR 1 2 O) n SiR 1 2 —R—NH 2 (VI)
is prepared by reacting an organosiloxane of the formula VII
HO(R 1 2 SiO) n R 1 2 SiOH (VII)
with a cyclic silazane of the formula V,
u having the values 0or 1,
v having the values 1-u and
n being a number from 1 to 20,000.
19 . The process of claim 12 , wherein the reaction zone is maintained at a temperature of from 0° C. to 100° C.
20 . The process of claim 12 , in which an amino-functional organosiloxane of the formula IX
(SiO 4/2 ) k (R 1 SiO 3/2 ) m (R 1 2 SiO 2/2 ) p (R l 3 SiO 1/2 ) q [O 1/2 SiR 1 2 —R—NH 2 ] s [O 1/2 H] t (O 1/2 SiR 1 3 ) w (IX)
is prepared by adding a silazane of the formula VI to an organosiloxane of the formula IV in less than a stoichiometric amount, and reacting unconverted Si—OH groups in the amino-functional organosiloxane of the formula III with a silazane of the formula VIII
in which
t is greater than or equal to 0,
w is greater than 0 and
s+t+w=r.
21 . The process of claim 20 , in which silazanes of the formula VIII are employed after reaction with a silazane of the formula V.
22 . The process of claim 12 , in which N-((3-aminopropyl)dimethylsilyl)-2,2-dimethyl-1-aza-2-silacyclopentane is used as at least one silazane of the formula (V).