DEFOAMING AGENT AND COMPOSITIONS CONTAINING THE DEFOAMING AGENT
A method of treatment of an aqueous foamable medium, such as a process stream of a pulp and paper mill, the method comprising contacting the aqueous process stream with a defoaming agent comprising: a) at least one C 12 to C 40 Guerbet alcohol; and/or, b) at least one polyol ester.
1 . A method of treatment of an aqueous foamable medium, the method comprising contacting the aqueous foamable medium with a defoaming agent comprising:
a) at least one C 12 to C 40 Guerbet alcohol; and/or,
b) at least one polyol ester.
2 . The method according to claim 1 , wherein the aqueous foamable medium is a process stream of a pulp and paper mill.
3 . The method according to claim 2 , wherein the contact time of the defoaming agent with the aqueous process stream is from 1 to 60 minutes.
4 . The method according to claim 2 , wherein the dosage of the defoaming agent contacting the aqueous process stream is from 0.1 to 1000 ppm by weight, based on the total weight of the aqueous process stream.
5 . The method according to claim 4 , wherein the dosage of the defoaming agent contacting the aqueous process stream is from 0.5 to 500 ppm by weight, based on the total weight of the aqueous process stream.
6 . An aqueous emulsion for the treatment of an aqueous foamable medium, the treatment emulsion comprising water and, based on the weight of the emulsion:
from 1 to 20 wt. % of a first defoaming agent consisting of:
a) at least one C 12 to C 40 Guerbet alcohol; and/or
b) at least one polyol ester;
from 1 to 30 to wt. % of c) at least one water-immiscible liquid polysiloxane; and,
from 0 to 5 wt. % of d) hydrophobic particles.
7 . The treatment emulsion according to claim 6 comprising water and, based on the weight of the emulsion:
from 1 to 15 wt. % of a first defoaming agent consisting of:
a) at least one C 12 to C 40 Guerbet alcohol; and/or
b) at least one polyol ester;
from 5 to 25 wt. % of c) at least one water-immiscible liquid polysiloxane; and,
from 1 to 5 wt. % of d) hydrophobic particles.
8 . The treatment emulsion according to claim 6 , wherein the first defoaming agent comprises or consists of at least one C 12 to C 40 Guerbet alcohol having the formula:
in which: R 8 and Rh are independently C 1 -C 20 alkyl; and,
the sum of the carbon atoms of R 8 and Rh is from 12 to 40.
9 . The treatment emulsion according to claim 8 , wherein the sum of the carbon atoms of R 8 and Rh is from 18 to 40.
10 . The treatment emulsion according to claim 8 , wherein the sum of the carbon atoms of R 8 and Rh is from 18 to 36.
11 . The treatment emulsion according to claim 8 , wherein the first defoaming agent comprises or consists of at least one C 12 to C 40 Guerbet alcohol chosen from: 2-hexyl-1-decanol; 2-octyl-1-decanol; 2-octyl-1-dodecanol; 2-hexyl-1-dodecanol; 2-decyl-1-tetradecanol; 2-dodecyl-1-hexadecanol; 2-tetradecyl-1-octadecanol; 2-hexadecyl-1-eicosanol; and, mixtures thereof.
12 . The treatment emulsion according to claim 6 , wherein the first defoaming agent comprises or consists of at least one partial or complete ester of a polyol possessing from 2 to 6 hydroxyl groups per molecule with a C 5 -C 30 saturated or unsaturated, linear fatty acid.
13 . The treatment emulsion according to claim 6 , wherein the first defoaming agent comprises or consists of at least one polyol ester chosen from: neopentyl glycol dioleate; trimethylolpropane dioleate; trimethylolpropane trioleate; trimethylolpropane triisostearate; trimethylolpropane tripelargonate (trimethylol trinonanoate); pentaerythritol tetraoleate; and, mixtures thereof.
14 . The treatment emulsion according to claim 6 , wherein the first defoaming agent comprises or consists of trimethylolpropane trioleate (TMPTO) and/or trimethylolpropane triisostearate.
15 . The treatment emulsion according to claim 6 , wherein the or each polysiloxane of part c) has a viscosity of from 100 to 100000 mPa·s, as measured at 25° C.
16 . The treatment emulsion according to claim 6 , wherein the or each polysiloxane of part c) has the following formula (C 1 ):
wherein: n is an integer of from 20 to 1000;
each R 1 is independently selected from C 1 -C 4 alkyl or C 6 -C 18 aryl; and,
each R 2 is independently selected from H, C 1 -C 4 alkyl or C 6 -C 18 aryl.
17 . The treatment emulsion according to claim 16 , wherein in Formula C 1 :
each R 1 is independently selected from C 1 -C 2 alkyl or C 6 aryl; and,
each R 2 is independently selected from H, C 1 -C 2 alkyl or C 6 aryl.
18 . The treatment emulsion according to claim 16 , wherein in Formula C 1 :
each R 1 is independently selected from methyl or phenyl; and,
each R 2 is independently selected from H, methyl or phenyl.
19 . The treatment emulsion according to claim 16 , wherein part c) comprises at least one polysiloxane chosen from poly(phenylmethylsiloxane), polydimethylsiloxane, polymethylhydrosiloxane and mixtures thereof.
20 . The treatment emulsion according to claim 6 , wherein part d) comprises or consists of hydrophobic particulate silica.