U.S. patent application number 13/976305 was filed with the patent office on 2013-11-14 for oil-in-water emulsions.
This patent application is currently assigned to BASF SE. The applicant listed for this patent is Wolfgang Gaschler. Invention is credited to Wolfgang Gaschler.
Application Number | 20130303635 13/976305 |
Document ID | / |
Family ID | 45478320 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130303635 |
Kind Code |
A1 |
Gaschler; Wolfgang |
November 14, 2013 |
OIL-IN-WATER EMULSIONS
Abstract
The invention relates to oil-in-water emulsions based on fatty
alcohols and the use thereof as antifoams or deaerators for aqueous
compositions. Such oil-in-water emulsions consist to at least 95%
by weight of the following constituents: a) 50 to 80% by weight, in
particular 55 to 75% by weight and specifically 60 to 70% by
weight, based on the total weight of the oil phase, of at least one
alkanol having at least 16 carbon atoms, in particular having 16 to
20 carbon atoms, where the fraction of alcohols having 16 to 18
carbon atoms constitutes at least 80% by weight, in particular 90%
by weight, specifically 95% by weight or at least 99%, based on the
total amount of component A, b) 1 to 10% by weight, in particular
to 2 to 8% by weight, specifically 3 to 6% by weight, based on the
total weight of the oil phase, of at least one further component B,
which is selected from esters of C.sub.12-C.sub.36-alkanecarboxylic
acids with polyglycerol and esters of
C.sub.12-C.sub.36-alkanecarboxylic acids with
C.sub.12-C.sub.36-alkanols, and mixtures thereof, c) 10 to 49% by
weight, in particular 20 to 40% by weight, specifically 25 to 35%
by weight, based on the total weight of the oil phase, of at least
one further component C, which is selected from organic substances
which are liquid at 50.degree. C. and 1013 mbar, at atmospheric
pressure have a boiling point above 200.degree. C., and at
25.degree. C. and 1013 mbar have a solubility in water of less than
0.1 g/l.
Inventors: |
Gaschler; Wolfgang;
(Niederwinkling, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gaschler; Wolfgang |
Niederwinkling |
|
DE |
|
|
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
45478320 |
Appl. No.: |
13/976305 |
Filed: |
January 9, 2012 |
PCT Filed: |
January 9, 2012 |
PCT NO: |
PCT/EP2012/050252 |
371 Date: |
June 26, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61431086 |
Jan 10, 2011 |
|
|
|
Current U.S.
Class: |
516/29 ;
516/133 |
Current CPC
Class: |
D21H 21/12 20130101;
D21H 21/14 20130101; B01D 19/0404 20130101 |
Class at
Publication: |
516/29 ;
516/133 |
International
Class: |
D21H 21/14 20060101
D21H021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 10, 2011 |
EP |
11150500.4 |
Claims
1: An oil-in-water emulsion, comprising: an oil phase, wherein the
oil phase comprises at least 95% by weight of from 50 to 80% by
weight, based on a total weight of the oil phase, of an alkanol
having at least 16 carbon atoms, wherein a fraction of the alkanol
having 16 to 18 carbon atoms comprises at least 80% by weight,
based on a total amount of the alkanol; from 1 to 10% by weight,
based on the total weight of the oil phase, of at least one ester
selected from the group consisting of a
C.sub.12-C.sub.36-alkanecarboxylic acid with polyglycerol and of a
C.sub.12-C.sub.36-alkanecarboxylic acid with a
C.sub.12-C.sub.36-alkanol; and from 10 to 49% by weight, based on
the total weight of the oil phase, of an organic substance, wherein
the organic substance is liquid at 50.degree. C. and 1013 mbar, at
atmospheric pressure the organic substance has a boiling point
above 200.degree. C., and at 25.degree. C. and 1013 mbar the
organic substance has a solubility in water of less than 0.1
g/l.
2: The oil-in-water emulsion according to claim 1, wherein the
alkanol consists essentially of unbranched alkanols.
3: The oil-in-water emulsion according to claim 1, wherein the
alkanol comprises at least 80% by weight of at least one alkanol is
selected from the group consisting of palmityl alcohol and stearyl
alcohol.
4: The oil-in-water emulsion according to claim 1, wherein the at
least one ester is at least 80% by weight from the ester comprising
a C.sub.18-C.sub.24-alkanecarboxylic acid with polyglycerol.
5: The oil-in-water emulsion according to claim 4, wherein
polyglycerol-comprising ester is obtained by esterification of
polyglycerol with behenic acid.
6: The oil-in-water emulsion according to claim 1, wherein the
organic substance comprises at least 80% by weight of an aliphatic
hydrocarbon oil.
7: The oil-in-water emulsion according to claim 1, wherein a solid
content of the oil-in-water emulsion is of from 10 to 50%.
8: The oil-in-water emulsion according to claim 1, wherein a
weight-average particle size of the oil-in-water emulsion is of
from 0.5 to 10 .mu.m.
9: A method for producing an antifoam or deaerator in an aqueous
composition, comprising: producing the antifoam or deaerator with
the oil-in-water emulsion according to claim 1.
10: A method for producing a deaerator for an aqueous paper stock
suspension, comprising: producing the deaerator for the aqueous
paper stock suspension with the oil-in-water emulsion according to
claim 1.
11: A method for producing a deaerator in a headbox of papermaking
comprising: producing the deaerator in the headbox of papermaking
with the oil-in-water emulsion according to claim 1.
12: A method of employing the oil-in-water emulsion according to
claim 8, comprising: employing the oil-in-water emulsion at a
temperature of from 20 to 50.degree. C.
13: The method according to claim 9, wherein the producing is
producing at a temperature of from 20 to 50.degree. C.
14: The method according to claim 10, wherein the producing is
producing at a temperature of from 20 to 50.degree. C.
15: The method according to claim 11, wherein the producing is
producing at a temperature of from 20 to 50.degree. C.
Description
[0001] The invention relates to oil-in-water emulsions based on
fatty alcohols and to the use thereof as antifoams or deaerators
for aqueous compositions.
[0002] In numerous industrial processes, it is necessary to handle
aqueous solutions and suspensions which have a tendency toward foam
formation on account of their ingredients. This foam formation
makes the process difficult to carry out and therefore has to be
kept as low as possible or avoided altogether. Examples of
foam-forming aqueous compositions are detergent-comprising
compositions, saponin-comprising compositions, wastewater in water
treatment plants, protein-comprising compositions such as soybean
extracts and in particular paper stock suspensions, e.g.
groundwood-and/or cellulose-comprising suspensions, as are used in
particular in the paper industry for producing paper, board or
cardboard.
[0003] Besides the formation of foam, which is permanently
after-formed from coalescing air bubbles, the air incorporated in
these systems, which is in a finely dispersed, stable form, also
proves to be problematical. The reduction in the air content of
these systems is therefore likewise of particular importance.
[0004] For these reasons, so-called antifoams and/or deaerators are
added to the film-forming aqueous compositions during their
processing and sometimes even during their production; these
antifoams and/or deaerators, even at low use concentrations,
suppress the undesired formation of foam, reduce the content of
incorporated air or destroy foam which has already been
produced.
[0005] The antifoams known from the prior art are often aqueous
compositions based on oil-in-water dispersions or emulsions, the
oil phase of which comprises at least one hydrophobic substance,
for example mineral oils, silicone oils, polyalkylene oxides,
esters thereof with fatty acids and ethers thereof with long-chain
alcohols, native fats and/or oils, waxes, ester waxes or long-chain
alcohols. Occasionally, the use of distillation residues which are
formed during the production of long-chain alcohols in accordance
with the Ziegler process or during oxo synthesis has also been
reported (see e.g. EP-A 149812).
[0006] U.S. Pat. No. 4,950,420 discloses antifoams for the paper
industry which comprise 10 to 90% by weight of a surface-active
polyether, such as polyalkoxylated glycerol or polyalkoxylated
sorbitol, and 10 to 90% by weight of a fatty acid ester of
polyhydric alcohols, such as mono- and diesters of polyethylene
glycol or polypropylene glycol.
[0007] EP-A 531713 and WO 94/08091 describe antifoams for the paper
industry based on oil-in-water emulsions, the oil phases of which
comprise alcohols, fatty acid esters, distillation residues,
hydrocarbons in combination with polyglycerol esters.
[0008] DE 2157033 describes antifoams based on aqueous emulsions
which comprise C.sub.12-C.sub.22-alkanols and/or
C.sub.12-C.sub.22-fatty acid esters of di- to trihydric alcohols
and paraffin oil or C.sub.12-C.sub.22-fatty acids.
[0009] Joshi et al. established in Colloids and Surfaces A:
Physicochem. Eng. Aspects 263 (2005) 239-249 that the effectiveness
of an antifoam based on fatty alcohol depends on its aggregate
state. The effectiveness is highest if it is partly molten. This
gives rise in the specialist field to the requirement to use
mixtures of fatty acid alcohols which, being mixtures, have a
broader melting range than pure substances.
[0010] In the prior art, the effectiveness of an antifoam is often
measured by its ability to suppress foam formation at a liquid
surface. Particularly in papermaking, however, it is also of
importance to reduce the air content in the aqueous liquids
produced during papermaking, particularly in the paper stock
suspensions. Antifoams which are likewise able to act as deaerators
are not often described in the prior art. The known antifoams often
leave something to be desired with regard to the deaerating effect,
particularly at temperatures below 50.degree. C., e.g. in the range
from 20 to <50.degree. C.
[0011] The object of the present invention is to provide
compositions which have high effectiveness both as antifoam and
also as deaerator for aqueous compositions, in particular for
aqueous paper stock suspensions.
[0012] These and other objects are achieved by oil-in-water
emulsions, the oil phase of which consists to at least 95% by
weight of the following constituents: [0013] a) 50 to 80% by
weight, in particular 55 to 75% by weight and specifically 60 to
70% by weight, based on the total weight of the oil phase, of at
least one alkanol having at least 16 carbon atoms, in particular
having 16 to 20 carbon atoms, where the fraction of alkanols having
16 to 18 carbon atoms constitutes at least 80% by weight, in
particular at least 90% by weight, specifically at least 95% by
weight or at least 99%, based on the total amount of component A,
[0014] b) 1 to 10% by weight, in particular 2 to 8% by weight,
specifically 3 to 6% by weight, based on the total weight of the
oil phase, of at least one further component B, which is selected
from esters of C.sub.12-C.sub.36-alkanecarboxylic acids with
polyglycerol and esters of C.sub.12-C.sub.36-alkanecarboxylic acids
with C.sub.12-C.sub.36-alkanols, and mixtures thereof, [0015] c) 10
to 49% by weight, in particular 20 to 40% by weight, specifically
25 to 35% by weight, based on the total weight of the oil phase, of
at least one further component C, which is selected from organic
substances which are liquid at 50.degree. C. and 1013 mbar, at
atmospheric pressure have a boiling point above 200.degree. C., and
at 25.degree. C. and 1013 mbar have a solubility in water of less
than 0.1 g/l.
[0016] Component A consists in particular of essentially unbranched
alkanols having at least 16, in particular 16 to 20, carbon atoms,
i.e. saturated alcohols having at least 16, in particular 16 to 20,
carbon atoms, in which the fraction of alcohols having 16 to 18
carbon atoms constitutes at least 80% by weight, in particular at
least 90% by weight, specifically at least 95% by weight or at
least 99%, based on the total amount of component A, and which are
linear to at least 80%, in particular at least 90% and specifically
at least 95%. Such linear alkanols can be described by the
following formula:
H--(CH.sub.2).sub.n--OH
in which n is an integer of at least 16 and in particular is in the
range from 16 to 20. The fraction of alkanols, in particular linear
alkanols having 16 to 18 carbon atoms, in particular having 16 or
18 carbon atoms, is according to the invention at least 80% by
weight, in particular at least 90% by weight, specifically at least
95% by weight or at least 99% by weight, based on the total weight
of component A. Examples of alcohols suitable as component A are
palmityl alcohol (cetyl alcohol), 1-heptadecanol, stearyl alcohol,
arachyl alcohol (n-eicosanol), behenyl alcohol and mixtures
thereof. Preferably, component A consists to at least 80%, in
particular at least 90% and specifically at least 95%, of palmityl
alcohol, stearyl alcohol or mixtures thereof.
[0017] According to the invention, component A comprises less than
20% by weight, based on component A, of alcohols having more than
18 carbon atoms. Preferably, component A comprises less than 10% by
weight, in particular less than 5% by weight, specifically less
than 1% by weight or less than 0.5% by weight, based on component
A, of alcohols having more than 18 carbon atoms.
[0018] In a likewise preferred embodiment, palmityl alcohol or
stearyl alcohol or a mixture of these alcohols is used as component
A whereas component A is free (less than 0.5% by weight, based on
component A) from alcohols having more than 18 carbon atoms.
[0019] According to the invention, the fraction of component A in
the oil phase is 50 to 80% by weight, preferably 55 to 75% by
weight, in particular 60 to 70% by weight, based on the total
weight of the oil phase.
[0020] Component B is selected from esters of alkanecarboxylic
acids with polyglycerol, esters of alkanecarboxylic acids with
alkanols and mixtures thereof.
[0021] Esters of alkanecarboxylic acids with polyglycerol are
understood as meaning a polyglycerol esterified with at least one
fatty acid which has 12 to 36, in particular 16 to 30, specifically
18 to 24, carbon atoms. The fatty acids contemplated for the
esterification of the polyglycerol may either be saturated fatty
acids or unsaturated fatty acids and mixtures thereof. Fatty acids
suitable for the esterification of the polyglycerol mixtures are
preferably selected from saturated fatty acids having 12 to 36, in
particular 16 to 30, specifically 18 to 24, carbon atoms. Examples
of suitable saturated fatty acids are lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, behenic acid and montan
wax acid. Examples of suitable unsaturated fatty acids are oleic
acid, hexadecanoic acids, elaidic acid, eicosenoic acids and
docosenoic acids such as erucic acid or brassidic acid, and also
polyunsaturated acids, such as octadecenedienoic acids and
octatrienoic acids, such as linoleic acid and linolenic acid, and
mixtures of the specified saturated and unsaturated carboxylic
acids. Preferably, the polyglycerol is esterified with saturated
carboxylic acids having 18 to 24 carbon atoms, which are selected
in particular from palmitic acid, stearic acid and behenic acid and
mixtures thereof. In a specific embodiment, the polyglycerol ester
is a polyglycerol esterified with behenic acid.
[0022] The degree of esterification of the polyglycerol esters is
generally 20 to 100%, preferably 60 to 100%, based on the number of
hydroxyl functions in the polyglycerol.
[0023] Preferred polyglycerol esters are in particular those which
are obtainable by esterifying polyglycerol mixtures which comprise
15 to 40% by weight of diglycerol, 30 to 55% by weight of
triglycerol and 10 to 25% by weight of tetraglycerol, in each case
based on the total amount of the polyglycerol, where the total
amount of di-, tri- and tetraglycerol constitutes at least 60% by
weight, in particular at least 80% by weight. In particular,
mixtures with the following composition are used for the
esterification:
0 to 10% by weight of glycerol, 15 to 40% by weight of diglycerol,
30 to 55% by weight of triglycerol, 10 to 25% by weight of
tetraglycerol, 0 to 15% by weight of pentaglycerol, 0 to 10% by
weight of hexaglycerol and 0 to 5% by weight of more highly
condensed polyglycerols.
[0024] In particular, the polyglycerol esters are those which are
obtainable by esterifying one of the polyglycerol mixtures
described above with at least one saturated carboxylic acid having
18 to 24 carbon atoms, the carboxylic acid being selected in
particular from palmitic acid, stearic acid and behenic acid and
mixtures thereof.
[0025] In the compositions according to the invention, particular
preference is given to those polyglycerol esters which are
obtainable by esterifying behenic acid with a polyglycerol mixture
which consists of 0 to 10% by weight of glycerol, 15 to 40% by
weight of diglycerol, 30 to 55% by weight of triglycerol, 10 to 25%
by weight of tetraglycerol, 0 to 15% by weight of pentaglycerol, 0
to 10% by weight of hexaglycerol and 0 to 5% by weight of more
highly condensed polyglycerols.
[0026] The polyglycerol mixtures used for the esterification are
accessible for example by alkaline catalyzed condensation of
glycerol at elevated temperatures (cf. e.g. Fette, Seifen,
Anstrichmittel, 88th volume, No. 3, pages 101 to 106 (1986)) or as
in DE-A 3842692 by reaction of glycerol with epichlorohydrin in the
presence of acidic catalysts at elevated temperatures. However, the
mixtures are also obtainable by mixing together the pure
polyglycerol components, e.g. diglycerol, triglycerol and
tetraglycerol.
[0027] The polyglycerols esterified with alkanecarboxylic acids are
known, e.g. from EP 531713 and WO 94/08091. They are typically
prepared by esterification of polyglycerol, in particular by
esterification of the polyglycerol mixtures described above, with
the desired fatty acid or mixture of fatty acids or ester-forming
derivatives thereof, e.g. C.sub.1-C.sub.4-alkyl esters thereof, by
methods known per se. As a rule, the procedure is carried out in
the presence of an acidic esterification catalyst such as sulfuric
acid, p-toluenesulfonic acid, citric acid, phosphorous acid,
phosphoric acid, hypophosphorous acid or basic catalysts, such as
sodium methylate or potassium tert-butylate.
[0028] Further suitable as component B are esters of
C.sub.12-C.sub.36-alkanecarboxylic acids with
C.sub.12-C.sub.36-alkanols. They are understood to include
substances which are obtainable by esterification of at least one,
preferably saturated, mono- to dibasic, preferably monobasic,
alkanecarboxylic acid having 12 to 36, in particular 16 to 30,
specifically 18 to 24, carbon atoms with a
C.sub.12-C.sub.36-alkanol. The alkanols suitable for the
esterification are preferably saturated, linear and mono- to
dihydric, in particular monohydric. They have 12 to 36, in
particular 16 to 30, specifically 18 to 24, carbon atoms. It is
also possible to use mixtures of alkyl esters of alkanoic acids.
Suitable examples of alkyl esters of alkanoic acids are palmityl
palmitate, stearyl stearate, arachyl arachate, behenyl behenate and
lignoceryl lignocerate. Preferred esters of
C.sub.12-C.sub.36-alkanecarboxylic acids with
C.sub.12-C.sub.36-alkanols are behenyl behenate and stearyl
stearate and mixtures thereof.
[0029] In one preferred embodiment, component B comprises at least
one of the above-described esters of alkanecarboxylic acids with
polyglycerol (also referred to below as polyglycerol esters), in
particular at least one of the polyglycerol esters stated as being
preferred or particularly preferred. In one preferred embodiment,
component B comprises at least one of the above-described
polyglycerol esters which is obtainable by esterification of the
above-described polyglycerol with at least one saturated carboxylic
acid having 18 to 24 carbon atoms, where the carboxylic acid is
selected in particular from palmitic acid, stearic acid and behenic
acid and mixtures thereof. In one particularly preferred
embodiment, component B comprises at least one of the
above-described polyglycerol esters which is obtainable by
esterification of behenic acid with a polyglycerol mixture
consisting of 0 to 10% by weight of glycerol, 15 to 40% by weight
of diglycerol, 30 to 55% by weight of triglycerol, 10 to 25% by
weight of tetraglycerol, 0 to 15% by weight of pentaglycerol, 0 to
10% by weight of hexaglycerol and 0 to 5% by weight of more highly
condensed polyglycerols.
[0030] In one preferred embodiment, component B consists to at
least 80% by weight, in particular to at least 90% by weight,
specifically to at least 95% by weight, based on the total weight
of component B, or exclusively of at least one of the
above-described polyglycerol esters, in particular at least one of
the polyglycerol esters stated as being preferred or particularly
preferred. In one particularly preferred embodiment, component B
consists to at least 80% by weight, in particular to at least 90%
by weight, specifically to at least 95% by weight, based on the
total weight of component B, or exclusively of at least one of the
above-described polyglycerol esters which is obtainable by
esterification of the above-described polyglycerol with at least
one saturated carboxylic acid having 18 to 24 carbon atoms, where
the carboxylic acid is selected in particular from palmitic acid,
stearic acid and behenic acid and mixtures thereof. In one
particularly preferred embodiment, component B consists to at least
80% by weight, in particular to at least 90% by weight,
specifically to at least 95% by weight, based on the total weight
of component B, or exclusively of at least one of the
above-described polyglycerol esters which is obtainable by
esterification of behenic acid with a polyglycerol mixture
consisting of 0 to 10% by weight of glycerol, 15 to 40% by weight
of diglycerol, 30 to 55% by weight of triglycerol, 10 to 25% by
weight of tetraglycerol, 0 to 15% by weight of pentaglycerol, 0 to
10% by weight of hexaglycerol and 0 to 5% by weight of more highly
condensed polyglycerols.
[0031] According to the invention, the fraction of component B in
the oil phase is 1 to 10% by weight, preferably 2 to 8% by weight,
in particular 3 to 6% by weight, based on the total weight of the
oil phase.
[0032] Component C present in the oil-in-water emulsions according
to the invention is one or more organic substances which are liquid
at 50.degree. C. and 1013 mbar, at atmospheric pressure have a
boiling point above 200.degree. C., e.g. in the range from 200 to
400.degree. C., in particular of at least 250.degree. C., and which
at 25.degree. C. and 1013 mbar are essentially insoluble in water,
i.e. have a solubility in water of less than 0.1 g/l. Suitable
substances are hydrocarbons and triglycerides of fatty acids, in
particular those having 12 to 22 carbon atoms. Component C
preferably consists to at least 80% by weight, in particular 90% by
weight, specifically 95% by weight, based on the total weight of
component C, of one or more hydrocarbons, which are in particular
nonaromatic, i.e. aliphatic or cycloaliphatic, and have a boiling
point of at least 200.degree. C., preferably at least 250.degree.
C., e.g. in the range from 200 to 400.degree. C. or 250 to
400.degree. C. at 1.013 bar, such as, for example, liquid
paraffins, white oils, soft paraffins or other standard commercial
mineral oils.
[0033] According to the invention, the fraction of component C in
the oil phase is 10 to 49% by weight, preferably 20 to 40, in
particular 25 to 35% by weight, based on the total weight of the
oil phase.
[0034] To stabilize the oil phase in the aqueous emulsion, the
emulsions according to the invention advantageously comprise at
least one surface-active substance. The emulsions according to the
invention comprise the at least one surface-active substance
generally in an amount from 0.1 to 10% by weight, in particular in
an amount from 0.5 to 5% by weight, based on the oil phase.
[0035] Suitable surface-active substances are, in principle, all
substances known for the stabilization of hydrophobic particles or
droplets in aqueous systems, e.g. anionic, cationic, amphoteric
and/or nonionic emulsifiers, and also water-soluble ionic and
nonionic polymers, preferably ionically amphiphilic copolymers
which have cationic or anionic groups and whose molecular weight,
in contrast to the emulsifiers, is usually above 1000 daltons.
Surface-active substances are sufficiently known to the person
skilled in the art, e.g. from Ullmann's Encyclopedia of Industrial
Chemistry, 5th ed. vol. A9, pp. 297-339.
Examples of Suitable Anionic Emulsifiers are
[0036] salts, in particular sodium and ammonium salts, of higher
fatty acids, salts, in particular the sodium and ammonium salts, of
sulfated ethoxylation products of C.sub.6-C.sub.22-alkylphenols,
such as nonylphenol or octylphenol, salts, in particular the sodium
and ammonium salts, of C.sub.4-C.sub.22-alkylarylsulfonates, salts,
in particular the sodium and ammonium salts, of sulfonates of
naphthalene, salts, in particular the sodium and ammonium salts, of
sulfonated C.sub.8-C.sub.22-alkyldiphenyl oxides, in particular of
bis-sulfonated C.sub.8-C.sub.22-alkyldiphenyl oxides, such as
bis-sulfonated dodecyldiphenyl oxide, salts, in particular the
sodium and ammonium salts, of naphthalenesulfonic acid-formaldehyde
condensates or naphthalenesulfonic acid-formaldehyde-urea
condensates, and also salts, in particular the sodium and ammonium
salts, of di-C.sub.4-C.sub.20-alkyl sulfosuccinates.
Examples of Suitable Nonionic Emulsifiers are:
[0037] alkoxylated C.sub.6-C.sub.22-alkylphenols with a degree of
ethoxylation of preferably in the range from 5 to 50, ethoxylated
unsaturated oils such as reaction products of castor oil with 30 to
40 mol equivalents of ethylene oxide, and adduct formation products
of ethylene oxide and/or propylene oxide with aliphatic alcohols
having as a rule 12 to 20 carbon atoms, e.g. with fatty alcohols,
with polyhydric alcohols, with amines, and also with carboxylic
acids.
[0038] The emulsions according to the invention preferably comprise
at least one emulsifier, in particular at least one anionic
emulsifier in an amount of from 0.1 to 10% by weight, in particular
in an amount of from 0.5 to 5% by weight, based on the oil phase.
In one specific embodiment, the emulsions according to the
invention comprise at least one anionic emulsifier selected from
the salts, in particular the sodium and ammonium salts, of sulfated
ethoxylation products of C.sub.6-C.sub.22-alkylphenols.
[0039] Examples of surface-active anionic polymers are homopolymers
of acrylic acid, homopolymers of methacrylic acid, copolymers of
acrylic acid and methacrylic acid in any desired molar ratio,
copolymers of acrylic acid and maleic acid in any desired molar
ratio, copolymers of methacrylic acid and maleic acid,
polyvinylsulfonic acid, polyacrylamido-2-methylpropanesulfonic
acid, styrenesulfonic acid, copolymers of acrylic acid and
acrylamide or methacrylamide, copolymers of methacrylic acid and
acrylamide or methacrylamide, or the alkali metal and ammonium
salts of the specified polymers with molar masses of, for example,
1500 to 300 000.
[0040] Preferred anionic surface-active polymers are amphiphilic
copolymers comprising acid groups and comprising, in copolymerized
form, [0041] (a) hydrophobic monoethylenically unsaturated monomers
and [0042] (b) monoethylenically unsaturated carboxylic acids,
monoethylenically unsaturated sulfonic acids, monoethylenically
unsaturated phosphonic acids or mixtures thereof, and optionally
monomers (c) different therefrom, and also the salts, in particular
the sodium and the ammonium salts, of such copolymers.
[0043] Examples of hydrophobic monoethylenically unsaturated
monomers are: styrene, methylstyrene, ethylstyrene, acrylonitrile,
methacrylonitrile, C.sub.2- to C.sub.18-olefins, esters of
monoethylenically unsaturated C.sub.3- to C.sub.5-carboxylic acids
and monohydric alcohols, vinyl alkyl ethers, vinyl esters or
mixtures thereof. From this group of monomers, preference is given
to using isobutene, diisobutene, styrene and acrylic acid esters
such as ethyl acrylate, isopropyl acrylate, n-butyl acrylate and
sec-butyl acrylate.
[0044] Examples of monomers (b) are: acrylic acid, methacrylic
acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid,
vinylsulfonic acid, 2-acrylamidomethylpropane-sulfonic acid,
acrylamidopropane-3-sulfonic acid, 3-sulfopropyl acrylate,
3-sulfopropyl methacrylate, styrenesulfonic acid, vinylphosphonic
acid or mixtures thereof, with preference being given to acrylic
acid, methacrylic acid and maleic acid and also their
anhydride.
[0045] The molar mass of the amphiphilic copolymers is generally
1000 to 100 000 and is preferably in the range from 1500 to 10 000.
The acid numbers of the anionic amphiphilic copolymers are
generally 50 to 500, preferably 150 to 350 mg of KOH/g of
polymer.
[0046] Suitable surface-active polymers for stabilizing the
compositions according to the invention are also: [0047] graft
polymers of 5 to 40 parts by weight of N-vinylformamide per 100
parts by weight of a polyalkylene glycol with a molar mass of from
500 to 10 000, [0048] zwitterionic polyalkylenepolyamines, [0049]
zwitterionic polyethyleneimines, [0050] zwitterionic
polyetherpolyamines or [0051] zwitterionic crosslinked
polyalkylenepolyamines.
[0052] Graft polymers of N-vinylformamide on polyalkylene glycols
are described, for example, in WO-A-96/34903. The grafted-on
vinylformamide units may optionally be up to 10% hydrolyzed. The
fraction of grafted-on vinylformamide units is preferably 20 to 40%
by weight, based on polyalkylene glycol. Preference is given to
using polyethylene glycols with molar masses of from 2000 to 10
000.
[0053] Zwitterionic polyalkylenepolyamines and zwitterionic
polyethyleneimines are known, for example, from EP-B 112592. Such
compounds are obtainable, for example, by firstly alkoxylating a
polyalkylenepolyamine or polyethyleneimine, e.g. with ethylene
oxide, propylene oxide, and/or butylene oxide, and then
quaternizing the alkoxylation products, e.g. with methyl bromide or
dimethyl sulfate, and then sulfating the quaternized alkoxylated
products with chlorosulfonic acid or sulfur trioxide. The molar
mass of the zwitterionic polyalkylenepolyamines is, for example,
1000 to 9000, preferably 1500 to 7500. The zwitterionic
polyethyleneimines preferably have molar masses in the range from
2000 to 1700 daltons.
[0054] The compositions according to the invention preferably
comprise at least one anionic surface-active substance. This is
preferably selected from the aforementioned anionic emulsifiers,
the aforementioned acid-carrying, water-soluble polymers and
mixtures thereof.
[0055] For the stability of the emulsions according to the
invention, it has proven advantageous if they comprise 0.05 to 8%
by weight, in particular 0.1 to 5% by weight, based on the oil
phase, of at least one acid-having water-soluble homo- or
copolymer, preferably of a salt thereof and optionally at least one
anionic emulsifier. The emulsifiers are preferably likewise used in
an amount of from 0.05 to 5% by weight, based on the total weight
of the oil phase. In particular, those emulsions which comprise at
least one anionic emulsifier and at least one of the aforementioned
acid-carrying water-soluble polymers are advantageous.
[0056] Besides the oil phase, the emulsions according to the
invention can comprise, as further disperse constituent, finely
divided, virtually water-insoluble, inert solids with particle
sizes (weight-average particle diameter) below 20 .mu.m, preferably
in the range from 0.1 to 10 .mu.m. If desired, the emulsion
according to the invention comprises these further inert solids in
an amount of, for example, 0.1 to 50% by weight, preferably 1 to
35% by weight, based on the weight of the oil phase of the
oil-in-water emulsions. Suitable inert solids are in particular
inorganic solids such as e.g. kaolin, chalk, bentonite, talc,
barium sulfate, silicon dioxide, zeolites, but also organic solids
such as urea-formaldehyde pigments, melamine-formaldehyde pigments
and microcrystalline cellulose, where the inert inorganic solids
may also be hydrophobized, e.g. by treatment with trialkylsilyl
halides. In contrast to the oil phase, these inert solids are solid
at a temperature of 100.degree. C. In one preferred embodiment of
the invention, the emulsions comprise no finely divided, virtually
water-insoluble, inert solids different from components A, B and
C.
[0057] As a rule, the solids content of the oil-in-water emulsion
according to the invention is in a range from 10 to 50% by weight,
in particular 15 to 45% by weight, specifically 20 to 40% by
weight, based on the total weight of the oil-in-water emulsion.
[0058] The emulsions according to the invention frequently comprise
one or more thickeners for setting the viscosity required for the
respective application. In principle, it is possible to use all
thickeners known for thickening oil-in-water systems. These include
natural thickeners such as polysaccharides, carrageenates,
Tragacanth, alginates, starch, caseinates, modified organic
polymers such as carboxymethylcellulose, synthetic thickeners such
as polyacrylic acids, polyvinyl alcohol, polyethylene glycols,
polyacrylamides, and, in particular, copolymers of acrylamide with
ethylenically unsaturated carboxylic acids, in particular with
acrylic acid, and optionally with comonomers. These thickeners are
described in EP-A 149 812, the disclosure of which is hereby
referred to. Further suitable thickeners are mentioned in the
overview article by Warren. B. Shapiro, Oil-in Water-Emulsions,
Cosmetics & Toiletries, vol. 97, 1982, 27-33. Particular
preference is also given to so-called associative thickeners, e.g.
hydrophobically modified polyurethanes, hydrophobically modified
cellulose ethers, which build up high molecular weight network
structures in accordance with the principle of hydrophobic
interaction in aqueous phase. Associative thickeners are known to
the person skilled in the art, e.g. J. Bielemann, Additives for
Coatings, Wiley-VCH Weinheim 2000 and are commercially available,
e.g. under the names RHOPLEX.RTM. and PRIMAL.RTM. TT 935 from Rohm
& Haas, USA. In one preferred embodiment of the invention, the
emulsions comprise no thickener.
[0059] In addition, the emulsions according to the invention also
frequently comprise commercially available biocides for
preservation, e.g. formaldehyde, isothiazolinone compounds such as
the products sold by Arch Chemicals under the name PROXEL.RTM. and
the products sold by Thor Chemie GmbH under the name
ACTICIDE.RTM..
[0060] To prepare the emulsion according to the invention, as a
rule the oil phase is emulsified in the aqueous phase. For this, a
melt of components A, B and C of the oil phase will usually be
incorporated, i.e. emulsified, into an aqueous phase which
optionally comprises one or more surface-active substances. The
incorporation and/or emulsification generally takes place at
temperatures above the melting point of the oil phase, e.g. at
temperatures in the range from 55 to 100.degree. C. The
incorporation takes place in a manner known per se for producing
emulsions by using apparatuses such as e.g. dispersing devices, in
which the components of the emulsion are subjected to a
considerable shear gradient. In order to obtain particularly stable
oil-in-water emulsions, the emulsification of the oil phase in the
aqueous phase is preferably carried out in the presence of
surface-active substances.
[0061] Emulsifying the oil phase in the aqueous phase gives
oil-in-water emulsions. Immediately after preparation, these
generally have a viscosity in the range from 300 to 3000 mPas
(determined in accordance with Brookfield at 25.degree. C., e.g.
with spindle 4 at 20 revolutions per minute).
[0062] The average particle size (weight average of the droplet
diameter) of the oil-in-water emulsion is generally below 25 .mu.m,
preferably in the range from 0.1 to 15 .mu.m, in particular 0.5 to
10 .mu.m, determined by means of light scattering at 20.degree.
C.
[0063] The oil-in-water emulsions according to the invention can be
used as antifoams and/or deaerators for controlling foam and/or
deaeration of aqueous media, for example in the food industry, the
starch industry, in waste treatment plants or in the paper
industry. Preference is given to their use as borehole solution and
in the paper industry, in particular during pulp cooking, pulp
washing, the grinding of paper stock, papermaking and the
dispersion of pigments for papermaking. Specifically, the
oil-in-water emulsions according to the invention are used in the
paper industry as deaerators of paper stock suspensions. Particular
preference is given here to the use as deaerators of the headbox in
papermaking.
[0064] As antifoams or deaerators, the oil-in-water emulsions are
generally used in amounts of from 0.01 to 2 parts by weight per 100
parts by weight of the foam-forming aqueous liquid, preferably in
amounts of from 0.02 to 1 part by weight per 100 parts by weight of
the foam-forming liquid, in particular in amounts of from 0.05 to
0.5 parts by weight per 100 parts by weight of the foam-forming
liquid.
[0065] The advantages of the emulsions according to the invention
are evident particularly at temperatures in the range from 20 to
50.degree. C.
[0066] The examples below are intended to illustrate the invention
in more detail and are not to be understood as being limiting.
Physicochemical Test Methods
[0067] The average particle size (weight-average particle diameter
d.sub.50) of the particles of the oil phase emulsified in water was
determined with the help of a Coulter counter from Beckmann.
[0068] The viscosity was determined using a Brookfield rotary
viscometer model RVT, spindle 4 at 20 revolutions per minute at
25.degree. C.
[0069] The solids content was determined by back-weighing the
samples following storage in a drying cabinet at 110.degree. C. to
constant weight.
[0070] The average air content was determined by pumping in each
case 101 of a foam-developing paper stock suspension 0.1%
(groundwood) in a container made of a transparent plastic for 5
minutes. The amount of air formed in the stock suspension was then
ascertained using an air measuring device (e.g. based on impedance
methods as in the case of the Sonica device from Conrex or based on
sonic speed measurements as in the case of Sonatrac from Cidra). To
assess the effectiveness of a deaerator, the average air content
was stated 5 minutes after adding the deaerator.
[0071] If the paper suspension is pumped round in the absence of an
antifoam for 5 minutes, then an average air content of 4% by volume
is obtained. By adding in each case 5 mg/l of an effective
deaerator to the paper stock suspension, this value is
significantly reduced, meaning that it is a measure of the
effectiveness of a deaerator.
[0072] After testing, the temperature of the paper stock suspension
in each case was 30 or 40.degree. C., the temperature being kept
constant to +/-1.degree. C. during the 5 minute test. In this
terminology, the more effective the antifoam, the lower the average
air content in the paper stock suspension.
[0073] The parts stated in the examples are parts by weight.
[0074] The C.sub.16/18-fatty alcohol used below as component A
consists to 32% by weight of a linear C.sub.16-alcohol, to 67% by
weight of a linear C.sub.18-alcohol and to 1% by weight of a linear
C.sub.20-alcohol. The melting range of this mixture is 51 to
52.degree. C.
[0075] The C.sub.20+-alcohol used in the comparative examples as
component A consisted of 3% by weight of a linear C.sub.18-alcohol,
45% by weight of a linear C.sub.20-alcohol, 25% by weight of a
linear C.sub.22-alcohol, 15% by weight of a linear C.sub.24-alcohol
and 12% by weight of higher alcohols. The melting range of this
mixture was 45.degree. C. to 54.degree. C.
[0076] The polyglycerol ester used as component B was prepared by
esterifying a polyglycerol mixture consisting of 27% diglycerol,
44% triglycerol, 19% tetraglycerol and 10% more highly condensed
polyglycerols with behenic acid. The degree of esterification was
60%.
[0077] The hydrocarbon (paraffin) used as component C has a melting
point of 38.degree. C.
[0078] The surface-active substances used were:
sodium salt of the sulfuric acid half-ester of isooctylphenol
ethoxylated with 25 mol/mol of ethylene oxide as anionic
emulsifier; anionic copolymer of 70% by weight of acrylamide and
30% by weight of acrylic acid with a K value of 270.
EXAMPLE 1
[0079] The components of the oil phase were firstly heated to a
temperature of 110.degree. C. and then incorporated into the
aqueous phase heated to 80.degree. C. by means of a dispersing
device.
[0080] The oil phase had the following composition, based on the
total weight of the emulsion: [0081] 20 parts of the
C.sub.16/18-fatty alcohol, [0082] 9 parts of paraffin and [0083] 1
part of polyglycerol ester.
[0084] The water phase consisted, based on the total weight of the
emulsion, of: [0085] 68.3 parts of water, [0086] 1 part of the
anionic emulsifier, [0087] 0.5 part of the anionic copolymer and
[0088] 0.2 part of sodium hydroxide solution.
[0089] The physical properties and the deaerating effect of this
emulsion are given in table 2.
[0090] The examples and comparative examples given in table 1 were
prepared in an analogous manner. The quantitative data are % by
weight, based on the total weight of the emulsion. The composition
of the water phase corresponded in all examples to the water phase
of example 1. The physical properties and the deaerating effect of
this emulsion are given in table 2.
TABLE-US-00001 TABLE 1 Example Component 1 2 3 4 5 C1 C2 C3 C4
C.sub.16/18-fatty 20 20 20 20 17.5 20 20 10 10 alcohol
C.sub.20+-alcohol -- -- -- -- 2.5 -- -- 10 5 Polyglycerol 1 -- 1 --
1 -- -- 1 1 ester Behenyl -- 3 -- 3 -- -- -- -- -- behenate
Paraffin 9 7 -- -- 9 -- 10 9 9 Palm oil -- -- 9 7 -- 10 -- --
--
TABLE-US-00002 TABLE 2 Physical properties and deaerating effect of
the antifoams Average particle Viscosity Solids content Air content
[%] size [.mu.m] [mPa s] [%] 30.degree. C. 40.degree. C. 1 2.1 420
29.8 0.1 0.1 2 2.2 470 29.9 0.1 0.1 3 2.1 450 29.7 0.2 0.2 4 2.0
490 29.8 0.2 0.2 5 2.3 440 29.9 0.3 0.2 C1 2.2 390 29.7 0.8 1.0 C2
2.2 420 29.8 1.0 1.2 C3 2.6 360 29.8 0.5 0.4 C4 2.3 390 29.9 0.4
0.4
* * * * *